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Hamburg, Germany

The University of Hamburg is a comprehensive university in Hamburg, Germany. It was founded on 28 March 1919, having grown out of the previous General lecture system and the Colonial Institute of Hamburg as well as the Akademic Gymnasium. In spite of its relatively short history, six Nobel Prize Winners and serials of scholars are affiliated to the university. University of Hamburg is the biggest research and education institution in Northern Germany and one of the most extensive universities in Germany. The main campus is located in the central district of Rotherbaum, with affiliated institutes and research centres spread around the city state. Wikipedia.

Jansen F.,University of Greifswald | Dengler J.,University of Hamburg
Journal of Vegetation Science | Year: 2010

Problem: The increasing availability of large vegetation databases holds great potential in ecological research and biodiversity informatics, However, inconsistent application of plant names compromises the usefulness of these databases. This problem has been acknowledged in recent years, and solutions have been proposed, such as the concept of "potential taxa" or "taxon views". Unfortunately, awareness of the problem remains low among vegetation scientists.Methods: We demonstrate how misleading interpretations caused by inconsistent use of plant names might occur through the course of vegetation analysis, from relevés upward through databases, and then to the final analyses. We discuss how these problems might be minimized.Results: We highlight the importance of taxonomic reference lists for standardizing plant names and outline standards they should fulfill to be useful for vegetation databases. Additionally, we present the R package vegdata, which is designed to solve name-related problems that arise when analysing vegetation databases.Conclusions: We conclude that by giving more consideration to the appropriate application of plant names, vegetation scientists might enhance the reliability of analyses obtained from large vegetation databases. © 2010 International Association for Vegetation Science.

Hack T.-P.,University of Hamburg | Schenkel A.,University of Wuppertal
General Relativity and Gravitation | Year: 2013

We develop a general setting for the quantization of linear bosonic and fermionic field theories subject to local gauge invariance and show how standard examples such as linearised Yang-Mills theory and linearised general relativity fit into this framework. Our construction always leads to a well-defined and gauge-invariant quantum field algebra, the centre and representations of this algebra, however, have to be analysed on a case-by-case basis. We discuss an example of a fermionic gauge field theory where the necessary conditions for the existence of Hilbert space representations are not met on any spacetime. On the other hand, we prove that these conditions are met for the Rarita-Schwinger gauge field in linearised pure N = 1 supergravity on certain spacetimes, including asymptotically flat spacetimes and classes of spacetimes with compact Cauchy surfaces. We also present an explicit example of a supergravity background on which the Rarita-Schwinger gauge field can not be consistently quantized. © 2013 Springer Science+Business Media New York.

Kursula P.,University of Oulu | Kursula P.,University of Hamburg
Amino Acids | Year: 2014

Calmodulin (CaM) is a highly conserved protein and a crucial calcium sensor in eukaryotes. CaM is a regulator of hundreds of diverse target proteins. A wealth of studies has been carried out on the structure of CaM, both in the unliganded form and in complexes with target proteins and peptides. The outcome of these studies points toward a high propensity to attain various conformational states, depending on the binding partner. The purpose of this review is to provide examples of different conformations of CaM trapped in the crystal state. In addition, comparisons are made to corresponding studies in solution. The different CaM conformations in crystal structures are also compared based on the positions of the metal ions bound to their EF hands, in terms of distances, angles, and pseudo-torsion angles. Possible caveats and artifacts in CaM crystal structures are discussed, as well as the possibilities of trapping biologically relevant CaM conformations in the crystal state. © 2014 Springer-Verlag Wien.

Schulte-Hengesbach F.,University of Hamburg
Journal of Geometry and Physics | Year: 2010

We classify six-dimensional Lie groups which admit a left-invariant half-flat SU(3)-structure and which split in a direct product of three-dimensional factors. Moreover, a complete list of those direct products is obtained which admit a left-invariant half-flat SU(3)-structure such that the three-dimensional factors are orthogonal. Similar classification results are proved for left-invariant half-flat SL(3,R)-structures on direct products with either definite and orthogonal or isotropic factors. © 2010 Elsevier B.V.

Reidegeld F.,University of Hamburg
Journal of Geometry and Physics | Year: 2010

We classify all cohomogeneity-one manifolds with principal orbit Q1,1,1=SU(2)3/U(1)2 or M1,1,0=(SU(3)SU(2))/(SU(2)U(1)) whose holonomy is contained in Spin(7). Various metrics with different kinds of singular orbits can be constructed by our methods. It turns out that the holonomy of our metrics is automatically SU(4) and that they are asymptotically conical. Moreover, we investigate the smoothness of the metrics at the singular orbit. © 2010 Elsevier B.V.

Schwarzenbach H.,University of Hamburg
Expert Opinion on Biological Therapy | Year: 2012

Introduction: Carcinogenesis is accompanied by deregulated tumor cell death and changes in proliferative processes. Apoptotic cells release different components, such as nucleosomes and caspases, into the blood circulation that can be detected by minimally invasive assays. Caspases belong to a large family of proteases, which are frequently overexpressed in various cancer entities and involved in metastases. One critical event of tumor invasion that signals the initiation of the metastatic cascade is the degradation of basement membrane components by protease supporting invasive cell migration and the dissemination of tumor cells. Areas covered: In consideration of PubMed publications, the current review article specifically focuses on the clinical utility of circulating nucleosomes along with protease and caspase activities and discusses the quantification of these parameters as potential, minimally invasive assay. Expert opinion: The quantification of these circulating cell death products is a promising marker for the pathogenesis of malignant diseases and monitoring of anticancer therapies. The measurement of circulating protease activities and tumor cells in the blood may provide additional information on tumor progression and metastases. © 2012 Informa UK, Ltd.

Di Mauro M.,University of Turin | Calore F.,University of Hamburg | Donato F.,University of Turin | Ajello M.,University of California at Berkeley | Latronico L.,National Institute of Nuclear Physics, Italy
Astrophysical Journal | Year: 2014

Active galactic nuclei (AGNs) with jets seen at small viewing angles are the most luminous and abundant objects in the γ-ray sky. AGNs with jets misaligned along the line of sight appear fainter in the sky but are more numerous than the brighter blazars. We calculate the diffuse γ-ray emission due to the population of misaligned AGNs (MAGNs) unresolved by the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope (Fermi). A correlation between the γ-ray luminosity and the radio-core luminosity is established and demonstrated to be physical by statistical tests, as well as compatible with upper limits based on Fermi-LAT data for a large sample of radio-loud MAGNs. We constrain the derived γ-ray luminosity function by means of the source-count distribution of the radio galaxies detected by the Fermi-LAT. We finally calculate the diffuse γ-ray flux due to the whole MAGN population. Our results demonstrate that MAGNs can contribute from 10% up to nearly the entire measured isotropic gamma-ray background. We evaluate a theoretical uncertainty on the flux of almost an order of magnitude. © 2014. The American Astronomical Society. All rights reserved.

Rehder D.,University of Hamburg
Future Medicinal Chemistry | Year: 2012

In the early treatment of diabetes with vanadium, inorganic vanadium compounds have been the focus of attention; organic vanadium compounds are nowadays increasingly attracting attention. A key compound is bis(maltolato)oxidovanadium, which became introduced into clinical tests Phase IIa. Organic ligands help modulate the bioavailability, transport and targeting mechanism of a vanadium compound. Commonly, however, the active onsite species is vanadyl (VO2+) or vanadate (H2VO4 -), generated by biospeciation. The mode of operation can be ascribed to interaction of vanadate with phosphatases and kinases, and to modulation of the level of reactive oxygen species interfering with phosphatases and/or DNA. This operating mode has also been inferred for most cancerostatic vanadium compounds, although some, for example vanadocenes, may directly intercalate with DNA. Novel medicinal potentiality of vanadium compounds is geared towards endemic diseases in tropical countries, in particular leishmaniasis, Chagas disease and amoebiasis, and viral infections such as Dengue fever, SARS and HIV. © 2012 Future Science Ltd.

Jackson C.R.,Global Ocean Associates | Alpers W.,University of Hamburg
Journal of Geophysical Research: Oceans | Year: 2010

A wide variety of oceanic and atmospheric phenomena are often observed in and around the sunglint region on optical images of the sea surface. The appearance of these phenomena depends strongly on the viewing geometry with areas on the sea surface that are rougher (or smoother) than the background appearing as either brighter or darker than the background depending on their position relative to the specular point. To understand these sea surface signature variations, this paper introduces the concept of a critical sensor viewing angle, defined as the sensor zenith angle at which different sea surface roughness variances produce identical sunglint radiance. It is when the imaging geometry transitions through the critical angle that a surface feature goes through a brightness reversal. Knowledge of where this transition takes place is important for properly interpreting the characteristics of the sea surface signature of these phenomena. The theory behind the concept of the critical angle is presented and then applied to sunglint imagery acquired over the ocean from space by the Moderate Resolution Imaging Spectroradiometer onboard NASA's Aqua and Terra satellites. © 2010 by the American Geophysical Union.

Augustin M.,University of Hamburg | Ogilvie A.,University Clinics of Erlangen
Dermatology | Year: 2010

Background: Nail involvement is a common feature of psoriasis, predicting higher disease severity and greater impairment in quality of life. Valid assessment of nail psoriasis is relevant for research and routine clinical use. However, no measurement standards have currently been developed. Objective: To identify state-of-the-art outcomes measurements in nail psoriasis by literature analysis. Methods: Systematic Web-based literature search, followed by structured critical appraisal and consecutive descriptive report. The search focused on methodological and epidemiological publications and papers describing outcomes of clinical trials on nail psoriasis. Results: Initially, 646 publications met the primary criteria. After non-relevant or replicate publications were excluded, 66 papers were analysed, including clinical trials or case reports (n = 41), reviews (n = 11) and methodological or epidemiological studies (n = 14). In total, 23 clinical outcomes measures and 15 patient-reported outcomes (PRO) tools were used. None had been validated according to recent standards. In the studies with clinical interventions (n = 41), NAPSI (Nail Psoriasis Severity Index; n = 4) or target NAPSI (n = 2) were the most often used single tools, followed by Physician's Global Assessment (n = 3). However, in 16 studies, no specifically described outcomes measures were used. Conclusion: Valid clinical outcomes measures in nail psoriasis are rare. Existing tools lack validation and standardisation. A need exists for accurate and scientifically sound evaluation of nail psoriasis severity in trials and clinical practice. To cover all elements of nail psoriasis, the optimal nail psoriasis assessment tool would include both PRO and physician-assessed outcomes measures. © 2010 S. Karger AG, Basel.

Hense I.,University of Hamburg
Journal of Marine Systems | Year: 2010

Models of harmful algal blooms (HABs) need to include autecological characteristics of the HAB species because the bloom dynamics can only be successfully described if relevant life cycle aspects (in particular en- and excystment) are included in some way. This study presents an overview on how the life cycle is considered in current Lagrangian and Eulerian models. Examples of the latter are given, which range from crude parameterizations in one-compartment models, to stage-resolving twelve-compartment models. Advantages and disadvantages of the different approaches are highlighted. A generalized model classification is presented which may be used as a framework for further phytoplankton life cycle modeling studies. © 2010 Elsevier B.V.

Kohl A.,University of Hamburg
Tellus, Series A: Dynamic Meteorology and Oceanography | Year: 2010

The pathways of the water that overflows the Greenland-Scotland Ridge and their source regions are studied with an ocean circulation model. Depending on the size of wind stress curl around Iceland, different water mass properties are found in the less dense fraction of the overflows on both sides of Iceland. Although in both cases, this fraction contributes to only a small part of the overflow, their pathways and associated source regions characterize also changes in the pathways of the denser fractions which is confirmed by backward float experiments. In detail, large Denmark Strait overflow during high wind stress curl conditions is associated with a primary pathway along the East Greenland Current with one branch encircling the Greenland Sea that is supplied by regions further southward while the other branch enters through Fram Strait. During low forcing conditions, the source region shifts into the Iceland Sea associated with a reversal of a current north of Iceland. The Faroe Bank Channel overflow is primarily fed by sources in the Norwegian Sea with water flowing southward along the Norwegian shelf. A smaller contribution that is enhanced during high forcing follows along the Jan Mayen Ridge and provides water from the Iceland Sea and the Greenland Sea. © 2010 The Author Journal compilation © 2010 Blackwell Munksgaard.

Buse J.,TU Dresden | Schoenefeld K.,TU Dresden | Munchau A.,University of Hamburg | Roessner V.,TU Dresden
Neuroscience and Biobehavioral Reviews | Year: 2013

Almost since the beginning of research on Tourette syndrome (TS), tics have been linked to a dysfunction of the dopamine (DA) system. At first, this assumption was mainly based on clinical findings of DA antagonists being the most effective drug in treating tics, but in recent years nuclear imaging has enabled a much deeper understanding of DA neurotransmission in TS. Based on the findings of various PET and SPECT studies the first part of the review discusses four hypotheses on DA dysfunctions in TS: (i) DA hyperinnervation, (ii) supersensitive DA receptors, (iii) pre-synaptic DA abnormality and (iv) DA tonic-phasic dysfunction. According to the latter hypothesis, reduced levels of tonic DA in the extracellular space lead to higher concentrations of DA in the axon terminal and an increase of stimulus-dependent DA release. The second part of the review addresses the modulating role of DA in some major clinical features of TS, like the exacerbation with stress or infection and the association with deficient sensorimotor gating. © 2012 Elsevier Ltd. All rights reserved.

Hausdorf B.,University of Hamburg | Hennig C.,University College London
Systematic Biology | Year: 2010

We propose a method for delimiting species based on dominant or codominant multilocus data using Gaussian clustering with a noise component for outliers. Case studies show that provisional species delimited using Gaussian clustering based on dominant multilocus data correspond well with provisional species delimited based on other data. However, the performance of Gaussian clustering in delimiting species based on few codominant markers was only moderate. Species represented by few individuals are usually included in the noise component because clusters are difficult to recognize with limited data. As alternative methods, we evaluated two model-based clustering methods originally proposed to infer population structure and assign individuals to populations based on the assumption of Hardy-Weinberg equilibrium within populations, namely STRUCTURE and STRUCTURAMA, as well as the "fields for recombination" approach. The latter resulted in lumping all individuals of each data set with codominant markers together, and whereas STRUCTURE often provides no decision about the number of clusters, STRUCTURAMA usually yields correct or almost correct numbers of clusters. The classification success of STRUCTURAMA analyses based on codominant markers was very good, but its performance with dominant markers was less consistent. Based on the classification success of the different methods for delimiting species with dominant and codominant multilocus markers in the case studies, we recommend using Gaussian clustering for data sets with dominant markers and STRUCTURAMA for data sets with codominant markers. © 2010 The Author(s).

Lehmberg K.,University of Hamburg | Ehl S.,University Hospital Freiburg
British Journal of Haematology | Year: 2013

Haemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory syndrome characterized by severely disturbed immune homeostasis. It can affect all age groups. Diagnostic evaluation of the patient with suspected HLH has to address three main questions: (i) does the patient have HLH? There is no simple diagnostic test, but a number of clinical and laboratory criteria define this clinical syndrome. (ii) Can a trigger be identified? A variety of infections, malignant or autoimmune diseases can contribute to the disturbed immune homeostasis with important consequences for treatment. (iii) Does the patient suffer from a genetic disease predisposing to HLH? Recent advances in the understanding of the genetic and pathophysiological basis of HLH have enabled a better and more rapid answer to this question, which is relevant for prognosis and the decision to perform haematopoietic stem cell transplantation. This review summarizes the current diagnostic approach to the patient with HLH. © 2012 Blackwell Publishing Ltd.

Zurawski N.,University of Hamburg
Sociological Quarterly | Year: 2011

Monitoring of consumers has become the most widespread mode of surveillance today. Being a multi-billion dollar business, the collected data are traded globally without much concern by the consumers themselves. Loyalty cards are an element with which such data are collected. Analyzing the role of loyalty cards in everyday practices such as shopping, I discuss how new modes of surveillance evolve and work and why they eventually make communication about data protection a difficult matter. Further, I will propose an alternative approach to the study of surveillance. This approach is concerned with local practices, focusing on subjective narratives in order to view surveillance as an integral part of culturally or socially manifested contexts and actions and not to view surveillance as something alien to society and human interaction. This will open up other possibilities to study modes of subjectivity or how individuals situate themselves within society. © 2011 Midwest Sociological Society.

Humbert A.,University of Hamburg
Annals of Glaciology | Year: 2010

Numerical simulations of the temperature regime of the ice shelf Fimbulisen, Antarctica, are presented. A vertical temperature profile (S1) of Fimbulisen has been measured at the extension of Jutulstraumen, in which the temperature decreases with depth. The three-dimensional steady-state temperature field was computed by a finite-element technique. Horizontal flow velocities and surface accumulation rates were derived from observations. The basal melt rate distribution arose from an assumption of balance in the mass continuity equation. The computed basal melt rate distribution (a b) indicates that the highest basal melt rates, up to 15 m a -1 occur at the inflow gate of Jutulstraumen, and low basal melt rates (<0.6 m a -1) occur in the slower moving parts. Where the ice shelf overhangs the continental shelf, a b ∼1.2 ma -1. The resulting temperature field indicates that Fimbulisen consists of a cold middle part, built up by the extension of Jutulstraumen, and warmer ice masses in slow-moving areas to the west and east. Furthermore, model runs were set up in which the atmospheric temperatures increased in +1 K steps. The results suggest that the warming effectively increases the temperatures throughout the ice column in the slower-moving parts, therefore enhancing shear at the margins of the extension of Jutulstraumen.

Boels R.H.,University of Hamburg
Nuclear Physics B | Year: 2013

A simple recursive expansion algorithm for the integrals of tree level superstring five point amplitudes in a flat background is given which reduces the expansion to simple symbol(ic) manipulations. This approach can be used for instance to prove the expansion is maximally transcendental to all orders and to verify several conjectures made in recent literature to high order. Closed string amplitudes follow from these open string results by the KLT relations. To obtain insight into these results in particular the maximal R-symmetry violating amplitudes (MRV) in type IIB superstring theory are studied. The obtained expansion of the open string amplitudes reduces the analysis for MRV amplitudes to the classification of completely symmetric polynomials of the external legs, up to momentum conservation. Using Molien's theorem as a counting tool this problem is solved by constructing an explicit nine element basis for this class. This theorem may be of wider interest: as is illustrated at higher points it can be used to calculate dimensions of polynomials of external momenta invariant under any finite group for in principle any number of legs, up to momentum conservation. © 2013 Elsevier B.V.

Heed T.,University of Hamburg
Current Biology | Year: 2010

The brain localizes touch not only on the skin, but also in three-dimensional space. A new study links behavioral findings in humans with neurophysiological findings in monkeys and suggests a model of how recoding from skin to space may be accomplished. © 2010 Elsevier Ltd..

Haag R.,University of Hamburg
Foundations of Physics | Year: 2013

The concept of event provides the essential bridge from the realm of virtuality of the quantum state to real phenomena in space and time. We ask how much we can gather from existing theory about the localization of an event and point out that decoherence and coarse graining-though important-do not suffice for a consistent interpretation without the additional principle of random realization. © 2013 Springer Science+Business Media New York.

Schafer I.,University of Hamburg | Fisher H.L.,Kings College London
Dialogues in Clinical Neuroscience | Year: 2011

In the last decade, a substantial number of population-based studies have suggested that childhood trauma is a risk factor for psychosis. In several studies, the effects held after adjusting for a wide range of potentially confounding variables, including genetic liability for psychosis. Less is known about the mechanisms underlying the association between childhood trauma and psychosis. Possible pathways include relationships between negative perceptions of the self, negative affect, and psychotic symptoms, as well as biological mechanisms such as dysregulated cortisol and increased sensitivity to stress. Psychotic patients with a history of childhood trauma tend to present with a variety of additional problems, including post-traumatic stress disorder, greater substance abuse, higher levels of depression and anxiety, and more frequent suicide attempts. Initial studies suggest that trauma-specific treatments are as beneficial for these patients as for other diagnostic groups.

Schneider J.M.,University of Hamburg
Cold Spring Harbor Perspectives in Biology | Year: 2014

Sexual cannibalism is a well-known example for sexual conflict and has many facets that determine the costs and benefits for the cannibal and the victim. Here, I focus on species in which sexual cannibalism is a general component of a mating system in which males invest maximally in mating with a single (monogyny) or two (bigyny) females. Sexual cannibalism can be a male strategy to maximize paternity and a female strategy to prevent paternity monopolization by any or a particular male. Considerable variation exists between species (1) in the potential of males to monopolize females, and (2) in the success of females in preventing monopolization by males. This opens up exciting future possibilities to investigate sexually antagonistic coevolution in a largely unstudied mating system. © 2014 Cold Spring Harbor Laboratory Press. All rights reserved.

During on-site inspections to verify the comprehensive nuclear-test-ban treaty (CTBT), soil gas samples may be taken and analysed for their content of the xenon isotopes 131mXe, 133Xe, 133mXe and 135Xe in order to identify a suspected underground nuclear test. These samples might contain natural radioxenon which is present as a trace gas in the ground. This work analyses the different production mechanisms of natural lithospheric radioxenon to assess theoretically the background concentration under different sampling conditions. The results imply that the equilibrium concentrations of the examined xenon isotopes can be measured in certain rock types using actual CTBTO on-site inspection equipment. Radioxenon production is dominated by spontaneous fission of 238U, resulting in a reactor-like xenon isotopic signature rather than an explosion-like signature. © 2010 Birkhäuser Verlag Basel/Switzerland.

Augustin M.,University of Hamburg
Current Problems in Dermatology (Switzerland) | Year: 2013

Cumulative life course impairment (CLCI) is a multidimensional construct, which reflects the overall increasing burden posed on patients by chronic (dermatological) disease. As such, CLCI can, to date, neither be directly measured nor can the patients' risk for CLCI be assessed by univocally defined screening scales. Presently, patients at risk for CLCI need to be identified by clinical, personal and psychosocial indicators and predictors of CLCI which need to be individually applied. Among those factors, the following are to be considered: (1) clinical disease severity; (2) chronic course of disease; (3) early onset of psoriasis; (4) perception of stigmatization; (5) lack of social support; (6) negative impact on profession; (7) 'negative' mood/personality trait; (8) coping strategy; (9) quality of life; (10) behaviors putting the patient at risk, and (11) comorbidities. Each of these factors requires accurate assessment either by clinical considerations or by specific tools. In particular, apart from other any single objectifiable risk factors, personality and social support of the patient can markedly affect the extent of CLCI and thus modulate the risks. Copyright © 2013 S. Karger AG, Base.

Use of induction therapy with mTOR inhibitor maintenance immunosuppression to facilitate reduced calcineurin inhibitor (CNI) exposure in de novo kidney transplant patients has been explored in a series of randomized trials. These studies have typically employed interleukin-2 receptor antagonist (IL-2RA) induction, in low or standard immunological risk recipients. Although no study has directly compared mTOR inhibition plus reduced CNI exposure with or without induction, inclusion of IL-2RA induction appears to permit a substantial reduction in CNI exposure without the need for high mTOR inhibitor dosing. IL-2RA induction with an mTOR inhibitor and steroids has consistently shown similar efficacy to standard-exposure CNI with mycophenolic acid and steroids and may improve renal function among patients who remain on the mTOR inhibitor-based regimen. With modern mTOR inhibitor dosing, wound healing complications are of less concern and may be no more frequent than in mycophenolic acid-based regimens. The incidence of cytomegalovirus infection appears lower in patients receiving de novo mTOR inhibition. The available evidence demonstrates that IL-2RA induction with an mTOR inhibitor can successfully reduce CNI exposure by at least half without a penalty in terms of rejection in low- or moderate-risk de novo transplant recipients and may offer renal and antiviral benefits. © 2013 John Wiley & Sons A/S.

Mirizzi A.,University of Hamburg
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

The flavor evolution of neutrinos emitted by a supernova (SN) core is strongly affected by the refractive effects associated with the neutrino-neutrino interactions in the deepest stellar regions. Till now, all numerical studies have assumed the axial symmetry for the "multi-angle effects" associated with the neutrino-neutrino interactions. Recently, it has been pointed out in Raffelt, Sarikas, and Seixas that if this assumption is removed, a new multi-azimuthal-angle (MAA) instability emerges in the flavor evolution of the dense SN neutrino gas, in addition to the one caused by multi-zenith-angle effects. Inspired by this result, for the first time we numerically solve the nonlinear neutrino propagation equations in SN, introducing the azimuthal angle as an angular variable in addition to the usual zenith angle. We consider simple energy spectra with an excess of νe over ν̄e. We find that even starting with a complete axial symmetric neutrino emission, the MAA effects would lead to significant flavor conversions in normal mass hierarchy, in cases otherwise stable under the only multi-zenith-angle effects. The final outcome of the flavor conversions, triggered by the MAA instability, depends on the initial asymmetry between νe and ν̄e spectra. If it is sufficiently large, final spectra would show an ordered behavior with spectral swaps and splits. Conversely, for small flavor asymmetries flavor decoherence among angular modes develops, also affecting the flavor evolution in the inverted mass hierarchy. © 2013 American Physical Society.

Wiesendanger R.,University of Hamburg
Current Opinion in Solid State and Materials Science | Year: 2011

Recent progress in atomic-resolution spin-polarized scanning tunneling microscopy (SP-STM) and spectroscopy (SP-STS) performed in external magnetic fields has led to a novel method of magnetometry at the single-atom level. Based on measurements of single-atom magnetization curves, magnetic interactions between individual atoms on surfaces can now be revealed in real space. Moreover, spin-selective imaging of orbital states of individual atoms has recently been achieved by SP-STM. The combination of STM-based single-atom manipulation techniques and single-atom magnetometry by SP-STM allows unprecedented insight into the magnetic properties of artificially created nanostructures. © 2010 Elsevier Ltd. All rights reserved.

Wilkens H.,University of Hamburg
Biological Journal of the Linnean Society | Year: 2016

Change in ecological conditions, as seen in surface and cave populations of Astyanax (Teleostei), has caused the divergent evolution of a large number of traits like eyes, coloration, taste, lateral line, and different kinds of behaviour like schooling, sleep or feeding posture. Because of the interfertility of surface and cave forms these fish are an exceptional object to study the morphological and genetic basis of the evolution of such complex regressive and constructive traits. Classical crossing analyses and genomic studies are contributing to growing understanding. Both kinds of traits mostly rely on multiple genetic bases and the phenotypic manifestation in the various crosses is similar. The gene effect underlying the phenotypic manifestation may exhibit an exponential increase at differing amounts in the various traits and crosses. Missing or presence of such genetic interaction helps determine whether the variability of eyes or pigmentation exhibited by Astyanax cave fish populations like Micos, is due to a more recent origin or to secondary hybridization with the surface fish. Neither crossing analysis nor QTL mapping revealed that eye reduction is pleiotropically antagonistically related to the increase of taste buds or lateral line sense. Independent inheritance of traits suggests that Astyanax cave fish are subjected to mosaic evolution. © 2016 The Linnean Society of London.

Eckstein M.,University of Hamburg | Werner P.,University of Fribourg
Physical Review Letters | Year: 2013

We investigate the properties of the metallic state obtained by photodoping carriers into a Mott insulator. In a strongly interacting system, these carriers have a long lifetime, so that they can dissipate their kinetic energy to a phonon bath. In the relaxed state, the scattering rate saturates at a nonzero temperature-independent value, and the momentum-resolved spectral function features broad bands which differ from the well-defined quasiparticle bands of a chemically doped system. Our results indicate that a photodoped Mott insulator behaves as a bad metal, in which strong scattering between doublons and holes inhibits Fermi-liquid behavior down to low temperature. © 2013 American Physical Society.

Pabst S.,German Electron Synchrotron | Santra R.,German Electron Synchrotron | Santra R.,University of Hamburg
Physical Review Letters | Year: 2013

We resolve an open question about the origin of the giant enhancement in the high-harmonic generation spectrum of atomic xenon around 100 eV. By solving the many-body time-dependent Schrödinger equation with all 4d, 5s, and 5p orbitals active, we truly demonstrate the enhancement results from the collective many-body excitation induced by the returning photoelectron via two-body interchannel interactions. Without the many-body interactions, which promote a 4d electron into the 5p vacancy created by strong-field ionization, no collective excitation and no enhancement in the high-harmonic generation spectrum exist. © 2013 American Physical Society.

Schuler M.,University of Bremen | Rosner M.,University of Bremen | Wehling T.O.,University of Bremen | Lichtenstein A.I.,University of Hamburg | Katsnelson M.I.,Radboud University Nijmegen
Physical Review Letters | Year: 2013

To understand how nonlocal Coulomb interactions affect the phase diagram of correlated electron materials, we report on a method to approximate a correlated lattice model with nonlocal interactions by an effective Hubbard model with on-site interactions U* only. The effective model is defined by the Peierls-Feynman-Bogoliubov variational principle. We find that the local part of the interaction U is reduced according to U *=U-V̄, where V̄ is a weighted average of nonlocal interactions. For graphene, silicene, and benzene we show that the nonlocal Coulomb interaction can decrease the effective local interaction by more than a factor of 2 in a wide doping range. © 2013 American Physical Society.

Rehder D.,University of Hamburg
Future Medicinal Chemistry | Year: 2016

Vanadium is omnipresent in trace amounts in the environment, in food and also in the human body, where it might serve as a regulator for phosphate-dependent proteins. Potential vanadium-based formulations-inorganic and coordination compounds with organic ligands-commonly underlie speciation in the body, that is, they are converted to vanadate(V), oxidovanadium(IV) and to complexes with the body's own ligand systems. Vanadium compounds have been shown to be potentially effective against diabetes Type 2, malign tumors including cancer, endemic tropical diseases (such as trypanosomiasis, leishmaniasis and amoebiasis), bacterial infections (tuberculosis and pneumonia) and HIV infections. Furthermore, vanadium drugs can be operative in cardio-and neuro-protection. So far, vanadium compounds have not yet been approved as pharmaceuticals for clinical use. © 2016 Future Science Ltd.

Hoffmann M.,University of Hamburg
Journal of Evaluation in Clinical Practice | Year: 2013

Population-based magnetic resonance imaging (MRI) generates many beneficial consequences for future generations of patients. But there are also some unintended implications for present patients and research subjects. The most important of these implications is the occurrence of incidental findings. In what follows, I will explicate two basic ethical problems concerning incidental findings. I will first argue that the main cause of these two problems lies in the conflicted nature of the medical researcher's role. I will then clarify the two problems, which involves appealing to two basic ethical requirements. The first problem originates from specific empirical conditions of epidemiological MRI research, which indicate shortcomings in the process of obtaining informed consent. The second problem is due to a conflict between obligations of beneficence for the research subjects and the researcher's duty to produce valid and generalizable study results. Finally, I will develop some preliminary perspectives for the solution of these problems. © 2013 John Wiley & Sons Ltd.

Wieser R.,University of Hamburg
Physical Review Letters | Year: 2013

The classical Landau-Lifshitz equation with a damping term has been derived from the time evolution of a quantum mechanical wave function under the assumption of a non-Hermitian Hamilton operator. Further, the trajectory of a classical spin (S) has been compared with the expectation value of the spin operator (S^). A good agreement between classical and quantum mechanical trajectories can be found for Hamiltonians linear in S^ or S, respectively. Quadratic or higher order terms in the Hamiltonian result in a disagreement. © 2013 American Physical Society.

Fulop J.A.,University of Pecs | Palfalvi L.,University of Pecs | Hoffmann M.C.,University of Hamburg | Hebling J.,University of Pecs
Optics Express | Year: 2011

Optical rectification of ultrashort laser pulses in LiNbO3 by tilted-pulse-front excitation is a powerful way to generate near single-cycle terahertz (THz) pulses. Calculations were carried out to optimize the output THz peak electric field strength. The results predict peak electric field strengths on the MV/cm level in the 0.3-1.5 THz frequency range by using optimal pump pulse duration of about 500 fs, optimal crystal length and cryogenic temperatures for reducing THz absorption in LiNbO3. The THz electric field strength can be increased further to tens of MV/cm by focusing. Using optimal conditions together with the contact grating technique THz pulses with 100 MV/cm focused electric field strength and energies on the tens-of-mJ scale are feasible. © 2011 Optical Society of America.

Tsuji N.,University of Fribourg | Eckstein M.,University of Hamburg | Werner P.,University of Fribourg
Physical Review Letters | Year: 2013

We study dynamical phase transitions from antiferromagnetic to paramagnetic states driven by an interaction quench in the fermionic Hubbard model using the nonequilibrium dynamical mean-field theory. We identify two dynamical transition points where the relaxation behavior qualitatively changes: one corresponds to the thermal phase transition at which the order parameter decays critically slowly in a power law â̂t-1/2, and the other is connected to the existence of nonthermal antiferromagnetic order in systems with effective temperature above the thermal critical temperature. The frequency of the amplitude mode extrapolates to zero as one approaches the nonthermal (quasi)critical point, and thermalization is significantly delayed by the trapping in the nonthermal state. A slow relaxation of the nonthermal order is followed by a faster thermalization process. © 2013 American Physical Society.

Baehr J.,Massachusetts Institute of Technology | Baehr J.,University of Hamburg
Journal of Physical Oceanography | Year: 2010

The incorporation of local temperature and salinity observations from the Rapid Climate Change-Meridional Overturning Circulation and Heatflux Array (RAPID-MOCHA), as well as the cable estimates of volume transport in the Florida Current (FC), is tested in the Estimating the Circulation and Climate of the Ocean-Global Ocean Data Assimilation Experiment (ECCO-GODAE) estimation system for their impact on the estimate of the meridional overturning circulation (MOC) and the meridional heat transport in the Atlantic. An experimental setup covering the first deployment period of RAPID-MOCHA from March 2004 to March 2005 is used to test different strategies for incorporating these datasets. Incorporating both monthly means of the FC data and monthly means of the RAPID-MOCHA temperature and salinity measurements at the eastern and western boundaries of the basin as an observational constraint in a 1-yr experiment results in an adjustment to the reference estimate, which does not include these datasets, of approximately 1 Sv (1 Sv ±106 m3 s-1) in the MOC at 26°N and the adjacent latitudes (approximately ±15°), with a larger northward branch of the MOC above 1000 m, compensated by a larger flow in the southward branch of the MOC between approximately 2000 and 3000 m. The meridional heat transport from 26°N to near 40°N is apsproximately 0.05 PW larger than in the reference experiment. © 2010 American Meteorological Society.

Boger R.H.,University of Hamburg
Alternative Therapies in Health and Medicine | Year: 2014

L-Arginine is a precursor for nitric oxide (NO) synthesis. NO is a ubiquitous mediator that is formed by a family of enzymes called NO synthases (NOSs). In the brain, NO acts as a neurotransmitter; in the immune system, it acts as a mediator of host defense; and in the cardiovascular system, it mediates the protective effects of the intact endothelium, acting as a vasodilator and endogenous, antiatherogenic molecule. About 5 g of L-arginine are ingested each day in a normal Western diet. Plasma levels of L-arginine are not significantly reduced in most diseases, except in end-stage renal failure during hemodialysis treatment. Nonetheless, intravenous or dietary (oral) administration of relatively large doses of L-arginine has been shown to result in enhanced NO formation in individuals with impaired endothelial function at baseline. In several controlled clinical trials, long-term administration of L-arginine has been shown to improve the symptoms of cardiovascular disease. However, in other trials, L-arginine was not beneficial, and in a recent study, the authors reported higher mortality for participants receiving L-arginine than for those receiving placebo. Recently, it became clear that endogenous levels of asymmetric dimethylarginine (ADMA), a competitive inhibitor of L-Arginine metabolism by NOS, may determine an individual’s response to L-arginine supplementation. L-Arginine appears to exert no effect in individuals with low ADMA levels, whereas in those with high levels, L-arginine restores the L-arginine/ADMA ratio to normal and, thereby, normalizes endothelial function. In conclusion, the effects of L-arginine supplementation on human physiology appear to be multicausal and dose-related. Doses of 3-8 g/d appear to be safe and not to cause acute pharmacologic effects in humans. © 2014, InnoVision Communications. All rights reserved.

Ondraczek J.,University of Hamburg | Ondraczek J.,International Institute For Applied Systems Analysis
Renewable and Sustainable Energy Reviews | Year: 2014

Despite the rapid decline in the cost of solar photovoltaic (PV) systems in the past five years., even recent academic research suggests that the cost of generating PV electricity remains too high for PV to make a meaningful contribution to the generation of grid electricity in developing countries. This assessment is reflected in the views of policymakers throughout Africa, who often consider PV as a technology suited only to remote locations and small-scale applications. This paper therefore analyzes whether, in contrast to conventional wisdom, PV is already competitive with other generation technologies. Analytically, the paper is based on a levelized cost of electricity (LCOE) model to calculate the cost of PV electricity in Kenya, which serves as a case study. Based on actual technology costs and Kenya's solar resource, the LCOE from PV is estimated at USD 0.21/kWh for the year 2011, with scenario results ranging from USD 0.17-0.30/kWh. This suggests that the LCOE of grid-connected PV systems may already be below that of the most expensive conventional power plants, i.e. medium-speed diesel generators and gas turbines, which account for a large share of Kenya's current power mix. This finding implies that researchers and policymakers may be mistaken in perceiving solar PV as a costly niche technology, rather than a feasible option for the expansion of power generation in developing countries. © 2013 Elsevier Ltd.

Vissing J.,Copenhagen University | Lukacs Z.,University of Hamburg | Straub V.,Northumbria University
JAMA Neurology | Year: 2013

The diagnosis of Pompe disease (acid maltase deficiency, glycogen storage disease type II) in children and adults can be challenging because of the heterogeneous clinical presentation and considerable overlap of signs and symptoms found in other neuromuscular diseases. This review evaluates some of the methods used in the diagnosis and differential diagnosis of late-onset Pompe disease. Muscle biopsy is commonly used as an early diagnostic tool in the evaluation of muscle disease. However, experience has shown that relying solely on visualizing a periodic acid-Schiff-positive vacuolar myopathy to identify late-onset Pompe disease often leads to false-negative results and subsequent delays in identification and treatment of the disorder. Serum creatine kinase level can be normal or only mildly elevated in late-onset Pompe disease and is not very helpful alone to suggest the diagnosis, but in combination with proximal and axial weakness it may raise the suspicion for Pompe disease. A simple blood-based assay to measure the level of α-glucosidase activity is the optimal initial test for confirming or excluding Pompe disease. A timely and accurate diagnosis of late-onset Pompe disease likely will improve patient outcomes as care standards including enzyme replacement therapy can be applied and complications can be anticipated. Increased awareness of the clinical phenotype of Pompe disease is therefore warranted to expedite diagnostic screening for this condition with blood-based enzymatic assays.

Brandao S.N.,University of Hamburg
Zoological Journal of the Linnean Society | Year: 2010

Animal communities inhabiting shallow marine benthic environments around Antarctica are quite well known, however, only a few studies deal with the deep-water faunas in the Southern Ocean. In the present study 19 deep-water samples and 14 shallow and mid-water samples containing macrocypridids were studied. The first important finding of the present study is the fivefold increase in the diversity of Macrocyprididae in the Southern Ocean: the species count increased from six to 30. Additionally, statistical analyses showed that depth is the main factor influencing macrocypridid assemblages and that geography does not play an important role. Two faunal bathymetric boundaries were observed, one around 1250 m and the other around 2500 m depth. Furthermore, species previously believed to be widely distributed (i.e. Macroscapha opaca, Macroscapha turbida, and Macroscapha inaequata) are shown to be groups of sometimes conspicuously distinct species. Over 30 Macrocyprididae species were identified from over 1200 specimens studied. After the study of the soft part morphology and chaetotaxy of Mh. opaca under the electron microscope, the following has been observed: (1) The exopodite of antenna II is clearly inserted on the distal margin of podomere II; (2) several setae previously considered aesthetascs (i.e. the long, proximal setae of podomere IV of the antenna II; the two sexually dimorphic setae of the podomere IV of antenna II; the modified setae of the podomeres II and III of the male appendage V) lack any pore, and should therefore not be chemoreceptors. Sixteen new species are described (Macromckenziea giambonini sp. nov., Macropyxis alanlordi sp. nov., Macropyxis cronini sp. nov., Macropyxis ghartmanni sp. nov., Macropyxis hornei sp. nov., Macropyxis jeans sp. nov., Macropyxis parajeans sp. nov., Macrosarisa andeep sp. nov., Macrosarisa fahrbachi sp. nov., Macroscapha cactus sp. nov., Macroscapha falcis sp. nov., Macroscapha rehmi sp. nov., Macroscapha scotia sp. nov., Macroscapha solecavai sp. nov., Macroscapha subhemispherica sp. nov., Macroscapha walterae sp. nov.). Five previously described species are recorded: Macromckenziea glacierae Maddocks 1990, Macroscapha inaequalis (G. W. Müller, 1908), Mh. inaequata Maddocks 1990, Mh. opaca Maddocks, 1990 species complex, Mh. turbida (G. W. Müller, 1908). At least nine species are left in open nomenclature. Moreover, Yemanja gen. nov. is described from shallow tropical waters of the Western Atlantic; Macrosarisa procera (Jellinek & Swanson, 2003) comb. nov. is proposed; and Macroscapha tensa (Müller, 1908) is herein considered a nomen dubium. © 2010 The Linnean Society of London.

Prygarin A.,University of Hamburg
Physical Review C - Nuclear Physics | Year: 2011

It is shown that the duality symmetry of the Balitsky-Fadin-Kuraev-Lipatov (BFKL) equation can be interpreted as a symmetry under rotation of the BFKL kernel in the transverse space from s channel (color-dipole model) to t channel (Reggeized gluon formulation). It is argued that the duality symmetry also holds in the nonforward case due to a very special structure of the nonforward BFKL kernel, which can be written as a sum of three forward BFKL kernels. The duality symmetry is established by identifying the dual coordinates with the transverse coordinates of a nondiagonal dipole scattered off the target. © 2011 American Physical Society.

Radjabian M.,Helmholtz Center Geesthacht | Abetz V.,Helmholtz Center Geesthacht | Abetz V.,University of Hamburg
Advanced Materials | Year: 2015

(Graph Presented). A simple way to generate isoporous membranes with tailored pore sizes is shown. Block copolymers of different compositions are blended in solution, and membranes are obtained by solution casting followed by nonsolvent-induced phase separation. This enables the preparation of integral asymmetric membranes with a defined pore size for given sets of block copolymers just by choosing the right blend composition. © 2014 Wiley-VCH Verlag GmbH & Co. KGaA.

Luhmann D.-S.,University of Hamburg
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2013

A versatile and numerically inexpensive method is presented allowing the accurate calculation of phase diagrams for bosonic lattice models. By treating clusters within the Gutzwiller theory, a surprisingly good description of quantum fluctuations beyond the mean-field theory is achieved approaching quantum Monte Carlo predictions for large clusters. Applying this powerful method to the Bose-Hubbard model, we demonstrate that it yields precise results for the superfluid to Mott-insulator transition in square, honeycomb, and cubic lattices. Due to the exact treatment within a cluster, the method can be effortlessly adapted to more complicated Hamiltonians in the fast progressing field of optical lattice experiments. This includes state- and site-dependent superlattices, large confined atomic systems, and disordered potentials, as well as various types of extended Hubbard models. Furthermore, the approach allows an excellent treatment of systems with arbitrary filling factors. We discuss the perspectives that allow for the computation of large, spatially varying lattices, low-lying excitations, and time evolution. © 2013 American Physical Society.

One still or again open problem of regional geoscientific importance is the existence or nonexistence of the so-called Bramscher Massif. This massif became a problem for hydrocarbon exploration in the past due to high maturities in the southern area of the Lower Saxony Basin, CO2-risks and lacking reservoir qualities related to it. The massif should have ascended as mafic intrusion during the Upper Cretaceous up to depths of 6 km (today). The existence of a massif of similar nature, the so-called Eastelbian Massif, reaching from Schleswig-Holstein to Brandenburg, which had also been identified by its gravimetric and magnetic anomalies, is disputed credibly meanwhile. The anomalies are located in the area of the eastern centre of the Southern Permian Basin (North German Basin) and are especially distinctive in Northwest Brandenburg through the local maxima of Pritzwalk. The origin of the observed anomalies in the area of Pritzwalk is suspected no more in depths of 6-10 km but after newer geophysical investigations probably in the deeper crust between 15 and 30 km of depth. Further, the analysis of the thermal development of the Lower Saxony Basin led to the assumption that the maturities within analysed wells can be much better explained by deep subsidence than by the effect of an intrusion. An alternative and comparative interpretation of further coexisting geophysical and geological anomalies also points to a justified questioning of the presently dominating interpretation and leads alternatively to an anomaly mass of eclogitic fancies below the magnetotelluricly imaged depth of about 15 km and above the depth of the magnetically significant Curie temperature (~25 km). If it is supposed that the intrusion does not exist at all with the suspected form, the structural and thermal development at the southern fringe of the Lower Saxony Basin has to be judged differently and the existence of present and possible Mesozoic and Palaeozoic gas fields in the area has to be to assessed again, as well as the distribution of minerals and ores in the Osna-brücker Bergland. © 2013 E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Germany.

Kalisch R.,Johannes Gutenberg University Mainz | Kalisch R.,University of Hamburg | Gerlicher A.M.V.,Johannes Gutenberg University Mainz
Neuroscience and Biobehavioral Reviews | Year: 2014

According to appraisal theories fear and anxiety are elicited by the subjective evaluation of a situation or internal state as threatening. From this perspective anxiety disorders result from maladaptive, exaggerated threat appraisals that over-estimate the threatening consequences of often innocuous stimuli and situations. When these threat over-estimations occur at the level of conscious processing, they are referred to as catastrophizing and worrying. Both are major pathogenic processes in many clinical theories of anxiety. Until recently, little has been known about the neurobiological basis of normal and pathological conscious threat appraisal. Here, we review functional neuroimaging studies which draw a consistent picture of the rostral part of the dorsal anterior cingulate (dACC) and the adjacent dorsomedial prefrontal cortex (dmPFC) as the likely key neural substrate of conscious threat appraisal. Moreover, findings of hyper-activation of the rostral dACC/dmPFC during catastrophizing and worrying emphasize its relevance to aberrant neural processing in anxiety disorders. These insights open a new avenue for improving the prevention and treatment of mental disorders that involve pathological appraisal. © 2014 Elsevier Ltd.

Kohl A.,University of Hamburg
Quarterly Journal of the Royal Meteorological Society | Year: 2015

We present results from a new synthesis (GECCO2) which covers the years 1948 to 2011 employing a similar configuration of the Massachusetts Institute of Technology general circulation model as the previous 50-year (1952 to 2001) GECCO synthesis. In GECCO2, the resolution was increased; it now includes the Arctic Ocean and a dynamic/thermodynamic sea ice model. The synthesis uses the adjoint method to bring the model into consistency with available hydrographic and satellite data as well as prior estimates of surface fluxes. In comparison to GECCO, GECCO2 provides a better agreement with the assimilated data, however the estimated flux adjustments remain similar to GECCO. Global heat content changes are in agreement with recent observational estimates and the estimate of the global heat flux is close to a radiative forcing estimate. Both show a clear effect of the radiative forcing from volcanic eruptions and a weak relation to ENSO events. In contrast to GECCO, the importance of the Denmark Strait overflow for the variability of the Atlantic Meridional Overturning Circulation (AMOC) is replaced in GECCO2 by water mass transformation in the subpolar gyre, which is shown to be part of the thermohaline circulation if the overturning is defined as a function of density. Heat and freshwater transport estimates in the Atlantic are more consistent with previous estimates than the unconstrained run. Decomposing heat and freshwater transports into overturning and gyre components by averaging on density coordinates demonstrates that in these coordinates the contribution from the gyre circulation largely disappears for heat transport and is reduced for the freshwater transport. © 2014 Royal Meteorological Society.

The 15N/14N isotopic ratio of marine particulate organic matter usually increases as a consequence of preferential 14N-remineralization (ammonification) during decay in the oxic water-column and at the oxic seafloor. However, a fractionation factor 15ε of sediment ammonification in natural environments has not been determined yet. Here, the 15ε of sedimentary ammonification is calculated in a set of seven sapropel containing sediment cores, two subrecent sediment cores and four sediment trap deployments from the Eastern Mediterranean Sea. Data clearly reveal Rayleigh type isotope fractionation and a fractionation factor 15ε between -1.43‰ and -2.3‰. Hence, sediments - and probably sinking particulate organic matter as well - can be important sources of isotopically depleted reactive nitrogen. The knowledge of 15ε further enables to reconstruct paleo export fluxes from sediment cores if original and actual δ15N as well as N accumulation rates are known. © 2012 Elsevier Ltd.

Portner H.O.,Alfred Wegener Institute for Polar and Marine Research | Peck M.A.,University of Hamburg
Journal of Fish Biology | Year: 2010

Ongoing climate change is predicted to affect individual organisms during all life stages, thereby affecting populations of a species, communities and the functioning of ecosystems. These effects of climate change can be direct, through changing water temperatures and associated phenologies, the lengths and frequency of hypoxia events, through ongoing ocean acidification trends or through shifts in hydrodynamics and in sea level. In some cases, climate interactions with a species will also, or mostly, be indirect and mediated through direct effects on key prey species which change the composition and dynamic coupling of food webs. Thus, the implications of climate change for marine fish populations can be seen to result from phenomena at four interlinked levels of biological organization: (1) organismal-level physiological changes will occur in response to changing environmental variables such as temperature, dissolved oxygen and ocean carbon dioxide levels. An integrated view of relevant effects, adaptation processes and tolerance limits is provided by the concept of oxygen and capacity-limited thermal tolerance (OCLT). (2) Individual-level behavioural changes may occur such as the avoidance of unfavourable conditions and, if possible, movement into suitable areas. (3) Population-level changes may be observed via changes in the balance between rates of mortality, growth and reproduction. This includes changes in the retention or dispersion of early life stages by ocean currents, which lead to the establishment of new populations in new areas or abandonment of traditional habitats. (4) Ecosystem-level changes in productivity and food web interactions will result from differing physiological responses by organisms at different levels of the food web. The shifts in biogeography and warming-induced biodiversity will affect species productivity and may, thus, explain changes in fisheries economies. This paper tries to establish links between various levels of biological organization by means of addressing the effective physiological principles at the cellular, tissue and whole organism levels. © 2010 The Authors. Journal of Fish Biology © 2010 The Fisheries Society of the British Isles.

Fittschen U.E.A.,University of Hamburg | Falkenberg G.,German Electron Synchrotron
Spectrochimica Acta - Part B Atomic Spectroscopy | Year: 2011

Microscopic X-ray fluorescence (micro-XRF) is a versatile tool in environmental analysis. We review work done in this field from 2008 to 2010 and highlight new aspects. Overall, there is a strong trend to combine fluorescence data with other data like diffraction or absorption spectroscopy. Also, the use of laboratory based instrumentation has become wide spread as more commercial instruments are available. At laboratories and synchrotron sites the trend towards higher spatial resolution is still persistent hitting sub micrometer values in case of synchrotron set ups. © 2011 Elsevier B.V. All Rights Reserved.

Rosch T.,University of Hamburg
Endoscopy | Year: 2012

The past few years have seen a shift in focus for endoscopy research. For example, there has been a halt in the apparent revolution of natural orifice transluminal surgery (NOTES), which was long considered the most important innovation in flexible endoscopy. Other trends such as endoscopic histology are slowing down and not progressing into clinical practice. In general, the quality of endoscopic research needs to be improved, particularly in the field of diagnostics and imaging 1. Nevertheless, progress in some areas continues, albeit at a slower pace than we might like. In this review the areas of current interest are reviewed with reference to the most relevant areas of progress in recent years. © Georg Thieme Verlag KG Stuttgart New York.

Caecilians have a unique dual jaw-closing system in that jaw closure is driven by the ancestral jaw-closing muscles (mm. levatores mandibulae) plus a secondarily recruited hyobranchial muscle (m. interhyoideus posterior). There is a variety of feeding habits (suction feeding, skin feeding, intrauterine scraping, and biting) during ontogeny that relate to reproductive modes in different caecilian species. This study examines the cranial biomechanics of caecilians in the suction-feeding larva of Ichthyophis cf. kohtaoensis, in the embryo and juvenile of the skin-feeding Boulengerula taitana, and in a newborn of the intrauterine feeder Typhlonectes natans. A lever arm model was applied to calculate effective mechanical advantages of jaw-closing muscles over gape angles and to predict total bite force in developing caecilians. In I. cf. kohtaoensis, Notable differences were found in the larval jaw-closing system compared to that of the adult. The suction-feeding larva of I. cf. kohtaoensis has comparatively large mm. levatores mandibulae that insert with an acute muscle fiber angle to the lower jaw and a m. interhyoideus posterior that has its optimal leverage at small gape angles. Conversely, the skin-feeding juvenile of B. taitana and the neonate T. natans are very similar in the feeding parameters considered herein compared to adult caecilians. Some ontogenetic variation in the feeding system of B. taitana before the onset of feeding was present. This study contributes to our understanding of the functional demands that feeding habits put on the development of cranial structures. © 2010 Elsevier GmbH.

Plochl M.,University of Osnabruck | Ossandon J.P.,University of Osnabruck | Konig P.,University of Osnabruck | Konig P.,University of Hamburg
Frontiers in Human Neuroscience | Year: 2012

Eye movements introduce large artifacts to electroencephalographic recordings (EEG) and thus render data analysis difficult or even impossible. Trials contaminated by eye movement and blink artifacts have to be discarded, hence in standard EEG-paradigms subjects are required to fixate on the screen. To overcome this restriction, several correction methods including regression and blind source separation have been proposed. Yet, there is no automated standard procedure established. By simultaneously recording eye movements and 64-channel-EEG during a guided eye movement paradigm, we investigate and review the properties of eye movement artifacts, including corneo-retinal dipole changes, saccadic spike potentials and eyelid artifacts, and study their interrelations during different types of eye- and eyelid movements. In concordance with earlier studies our results confirm that these artifacts arise from different independent sources and that depending on electrode site, gaze direction, and choice of reference these sources contribute differently to the measured signal. We assess the respective implications for artifact correction methods and therefore compare the performance of two prominent approaches, namely linear regression and independent component analysis (ICA). We show and discuss that due to the independence of eye artifact sources, regression-based correction methods inevitably over- or under-correct individual artifact components, while ICA is in principle suited to address such mixtures of different types of artifacts. Finally, we propose an algorithm, which uses eye tracker information to objectively identify eye-artifact related ICA-components (ICs) in an automated manner. In the data presented here, the algorithm performed very similar to human experts when those were given both, the topographies of the ICs and their respective activations in a large amount of trials. Moreover it performed more reliable and almost twice as effective than human experts when those had to base their decision on IC topographies only. Furthermore, a receiver operating characteristic (ROC) analysis demonstrated an optimal balance of false positive and false negative at an area under curve (AUC) of more than 0.99. Removing the automatically detected ICs from the data resulted in removal or substantial suppression of ocular artifacts including microsaccadic spike potentials, while the relevant neural signal remained unaffected. In conclusion the present work aims at a better understanding of individual eye movement artifacts, their interrelations and the respective implications for eye artifact correction. Additionally, the proposed ICA-procedure provides a tool for optimized detection and correction of eye movement-related artifact components. © 2012 Plöchl,Ossandón and K̈nig.

Miranda P.M.A.,University of Lisbon | Alves J.M.R.,University of Lisbon | Serra N.,University of Hamburg
Climate Dynamics | Year: 2013

The regional ocean modeling system is used, at a resolution of 1/12°, to explicitly simulate the ocean circulation near the Iberian coast during two 30-year simulations forced by atmospheric fields produced by the RACMO regional climate model. The first simulation is a control run for the present climate (1961-1990) and the second is a scenario run from the IPCC A2 scenario (2071-2100). In the control run, the model reproduces some important features of the regional climate but with an overestimation of upwelling intensity, mainly attributable to inaccuracies in the coastal wind distributions when compared against reanalysis data. A comparison between the scenario and control simulations indicates a significant increase in coastal upwelling, with more frequent events with higher intensity, leading to an overall enhancement of SST variability on both the intra- and inter-annual timescales. The increase in upwelling intensity is more prominent in the northern limit of the region, near cape Finisterre, where its mean effect extends offshore for a few hundred kms, and is able to locally cancel the effect of global warming. If these results are confirmed, climate change will have a profound impact on the regional marine ecosystem. © 2012 Springer-Verlag.

Malyutina M.V.,RAS A.V. Zhirmunsky Institute of Marine Biology | Golovan O.A.,RAS A.V. Zhirmunsky Institute of Marine Biology | Elsner N.O.,University of Hamburg
Deep-Sea Research Part II: Topical Studies in Oceanography | Year: 2013

A small collection of isopods of the family Munnopsidae Lilljeborg, 1864, including four species from the slope and the deep-sea basin of the Sea of Japan (Northwest Pacific), was studied. The new species Baeonectes brandtae sp. nov. which occurs at depths of 455-1525. m is described. It is the second species of Baeonectes Wilson, 1982 described from the Sea of Japan and the deepest recorded species of the genus. Eurycope spinifrons Gurjanova, 1933, the only Eurycope species known from the Sea of Japan is redescribed. It is the most abundant species in the studied deep-sea macrobenthic communities in all samples. © 2012 Elsevier Ltd.

Mitropoulos D.,National and Kapodistrian University of Athens | Artibani W.,University of Verona | Graefen M.,University of Hamburg | Remzi M.,Landesklinikum Korneuburg | And 2 more authors.
European Urology | Year: 2012

Context: The incidence of postoperative complications is still the most frequently used surrogate marker of quality in surgery, but no standard guidelines or criteria exist for reporting surgical complications in the area of urology. Objective: To review the available reporting systems used for urologic surgical complications, to establish a possible change in attitude towards reporting of complications using standardised systems, to assess systematically the Clavien-Dindo system when used for the reporting of complications related to urologic surgical procedures, to identify shortcomings in reporting complications, and to propose recommendations for the development and implementation of future reporting systems that are focused on patient-centred outcomes. Evidence acquisition: Standardised systems for reporting and classification of surgical complications were identified through a systematic review of the literature. To establish a possible change in attitude towards reporting of complications related to urologic procedures, we performed a systematic literature search of all papers reporting complications after urologic surgery published in European Urology, Journal of Urology, Urology, BJU International, and World Journal of Urology in 1999-2000 and 2009-2010. Data identification for the systematic assessment of the Clavien-Dindo system currently used for the reporting of complications related to urologic surgical interventions involved a Medline/Embase search and the search engines of individual urologic journals and publishers using Clavien, urology, and complications as keywords. All selected papers were full-text retrieved and assessed; analysis was done based on structured forms. Evidence synthesis: The systematic review of the literature for standardised systems used for reporting and classification of surgical complications revealed five such systems. As far as the attitude of urologists towards reporting of complications, a shift could be seen in the number of studies using most of the Martin criteria, as well as in the number of studies using either standardised criteria or the Clavien-Dindo system. The latter system was not properly used in 72 papers (35.3%). Conclusions: Uniformed reporting of complications after urologic procedures will aid all those involved in patient care and scientific publishing (authors, reviewers, and editors). It will also contribute to the improvement of the scientific quality of papers published in the field of urologic surgery. When reporting the outcomes of urologic procedures, the committee proposes a series of quality criteria. © 2011 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Voskuhl R.R.,University of California at Los Angeles | Gold S.M.,University of Hamburg
Nature Reviews Neurology | Year: 2012

The pathogenesis of multiple sclerosis (MS) involves complex interactions between genetic susceptibility and environmental triggers. Clinical observations suggest that the study of sex differences might provide important insight into mechanisms of pathogenesis and progression of the disease in patients. MS occurs more frequently in women than in men, indicating that sex-related factors have an effect on an individual's susceptibility to developing the condition. These factors include hormonal, genetic and environmental influences, as well as gene-environment interactions and epigenetic mechanisms. Interestingly, women do not have a poorer prognosis than men with MS despite a higher incidence of the disease and more-robust immune responses, which suggests a mechanism of resilience. Furthermore, the state of pregnancy has a substantial effect on disease activity, characterized by a reduction in relapse rates during the third trimester but an increased relapse rate in the postpartum period. However, pregnancy has little effect on long-term disability in women with MS. The unravelling of the mechanisms underlying these clinical observations in the laboratory and application of the results to the clinical setting is a unique and potentially fruitful strategy to develop novel therapeutic approaches for MS © 2012 Macmillan Publishers Limited. All rights reserved.

Kocalevent R.-D.,University of Hamburg | Hinz A.,University of Leipzig | Brahler E.,University of Leipzig
BMC Psychiatry | Year: 2013

Background: The PHQ-15 is widely used as an open access screening instrument for somatization syndromes in different health care settings, thus far, normative data from the general population are not available. The objectives of the study were to generate normative data and to further investigate the construct validity of the PHQ-15 in the general population.Methods: Nationally representative face-to face household surveys were conducted in Germany between 2003 and 2008 (n=5,031). The survey questionnaires included, the 15-item somatization module from the Patient Health Questionnaire (PHQ-15), the 9-item depression module (PHQ-9), the Satisfaction With Life Scale (SWLS), the SF-12 for the measurement of health related quality of life, and demographic characteristics.Results: Normative data for the PHQ-15 were generated for both genders and different age levels including 5031 subjects (53.6% female) with a mean age (SD) of 48.9 (18.1) years. Somatization syndromes occured in 9.3% of the general population. Women had significantly higher mean (SD) scores compared with men [4.3 (4.1) vs. 3.4 (4.0)]. Intercorrelations with somatization were highest with depression, followed by the physical component summary scale of health related quality of life.Conclusions: The normative data provide a framework for the interpretation and comparisons of somatization syndromes with other populations. Evidence supports reliability and validity of the PHQ-15 as a measure of somatization syndromes in the general population. © 2013 Kocalevent et al.; licensee BioMed Central Ltd.

Hack T.-P.,University of Hamburg | Makedonski M.,Copenhagen University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2013

It is well known that coupling a spin-3/2 field to a gravitational or electromagnetic background leads to potential problems both in the classical and in the quantum theory. Various solutions to these problems have been proposed so far, which are all restricted to a limited class of backgrounds. On the other hand, negative results for general gravitational backgrounds have been reported only for a limited set of couplings to the background to date. Hence, to our knowledge, a comprehensive analysis of all possible couplings to the gravitational field and general gravitational backgrounds including off-shell ones has not been performed so far. In this work we analyse whether it is possible to couple a spin- 32 field to a gravitational field in such a way that the resulting quantum theory is consistent on arbitrary gravitational backgrounds. We find that this is impossible as all couplings require the background to be an Einstein spacetime for consistency. This enforces the widespread belief that supergravity theories are the only meaningful models which contain spin- 32 fields as in these models such restrictions of the gravitational background appear naturally as on-shell conditions. © 2012 Elsevier B.V.

Kesting M.-L.,University of Marburg | Lincoln T.M.,University of Hamburg
Comprehensive Psychiatry | Year: 2013

Background Self-esteem is frequently targeted in psychological approaches to persecutory delusions (PD). However, its precise role in the formation and maintenance of PD is unclear and has been subject to a number of theories: It has been hypothesized that PD function to enhance self-esteem, that they directly reflect negative conceptualizations of the self, that self-esteem follows from the perceived deservedness of the persecution (poor-me versus bad-me-paranoia) and that the temporal instability of self-esteem is relevant to PD. In order to increase our understanding of the relevance of self-esteem to PD, this article systematically reviews the existing research on self-esteem in PD in the light of the existing theories. Methods We performed a literature search on studies that investigated self-esteem in PD. We included studies that either investigated self-esteem a) within patients with PD or compared to controls or b) along the continuum of subclinical paranoia in the general population. We used a broad concept of self-esteem and included paradigms that assessed implicit self-esteem, specific self-schemas and dynamic aspects of self-esteem. Results The literature search identified 317 studies of which 52 met the inclusion criteria. The reviewed studies consistently found low global explicit self-esteem and negative self-schemas in persons with PD. The studies therefore do not support the theory that PD serve to enhance self-esteem but underline the theory that they directly reflect specific negative self-schemas. There is evidence that low self-esteem is associated with higher perceived deservedness of the persecution and that PD are associated with instable self-esteem. Only few studies investigated implicit self-esteem and the results of these studies were inconsistent. Conclusions We conclude by proposing an explanatory model of how self-esteem and PD interact from which we derive clinical implications. © 2013 Elsevier Inc. All rights reserved.

Rehder D.,University of Hamburg
Coordination Chemistry Reviews | Year: 2011

Extraterrestrial vanadium compounds typically contain vanadium in low oxidation states (VII, VIII), reflecting anoxic environments (low oxygen fugacities) during genesis. In meteorites, most of which are fragments from asteroids and thus represent samples from the very beginning of our solar system, are found the pyroxenes which are typical VII bearing minerals. In calcium- and aluminium-rich inclusions of dust particles collected from the coma of comet Wild 2, osbornite (TiN) with titanium replaced by up to 63% vanadium has been found. The atmospheres of " hot Jupiter" type exoplanets, as well as the atmospheres of early M type stars (red dwarfs) contain vanadium(II)oxide, which is also likely a constituent in interstellar clouds. The relevance of these vanadium occurrences for the generation of complex molecules out of simple ones under primordial conditions is briefly discussed in light of the catalytic potential of vanadium nitrides and -oxides. At higher oxygen fugacities, oxidic VIV and VV species are available. In this context, the ability of higher valent vanadium oxides to form nano-structured webs of protocells, and the potential of decavanadate and VO2+ to interfere with chemical processes in micellar structures and lipid vesicles is addressed. © 2011 Elsevier B.V.

Fittschen U.E.A.,University of Hamburg | Falkenberg G.,German Electron Synchrotron
Analytical and Bioanalytical Chemistry | Year: 2011

In this review we highlight the performance of confocal micro X-ray fluorescence (CMXRF) for application in environmental science, citing contributions from recent studies (2008-2010). In CMXRF the use of focusing and collecting optics enables discrimination of the origin of fluorescence photons in three dimensions. It thereby enables simple and direct three dimensional imaging, and also the removal of unwanted signal contribution either from the depth of the sample or from its surface. By limiting the area of origin of fluorescence signal CMXRF can simplify quantitative approaches. © 2011 Springer-Verlag.

Gao Z.,CAS Institute of Theoretical Physics | Yang G.,University of Hamburg
Journal of High Energy Physics | Year: 2013

We study form factors in N=4 SYM at strong coupling in general kinematics and with multi-operator insertions by using gauge/string duality and integrability techniques. This generalizes the AdS3 results of Maldacena and Zhiboedov in two non-trivial aspects. The first generalization to AdS5 space was motivated by its potential connection to strong coupling Higgs-to-three-gluons amplitudes in QCD which was observed recently at weak coupling. The second generalization to multi-operator insertions was motivated as a step towards applying on-shell techniques to compute correlation functions at strong coupling. In this picture, each operator is associated to a monodromy condition on the cusp solutions. We construct Y-systems for both cases. The Y -functions are related to the spacetime (cross) ratios. Their WKB approximations based on a rational function P (z) are also studied. We focus on the short operators, while the prescription is hopefully also applicable for more general operators. © 2013 SISSA, Trieste, Italy.

Saad F.,University of Montreal | Saad F.,Institute Du Cancer Of Montreal | Pantel K.,University of Hamburg
Future Oncology | Year: 2012

Prostate-specific antigen (PSA) has been used for over two decades as a serum marker for adenocarcinoma of the prostate. Although PSA screening remains an important part of disease screening and monitoring in early prostate cancer (PC), its utility in monitoring disease progression in advanced PC is undetermined. Furthermore, the role of PSA monitoring in the management of patients with PC and bone metastases appears limited. The purpose of this review is to evaluate the role of circulating tumor cells (CTCs) as potential novel biomarkers in advanced PC. We present a review of CTC testing and the clinical data supporting the prognostic potential of CTCs in this setting. We propose that combination of CTCs and PSA velocity or doubling-time assessments may offer insights into the prognosis and management of advanced PC. © 2012 Future Medicine Ltd.

Franzke C.L.E.,University of Hamburg
Geophysical Research Letters | Year: 2015

Ecosystems and societies are highly vulnerable to extreme temperatures and to changes in the range of temperatures at local scales. Here I will show how trends in warm and cold extremes have evolved over the last six decades in Europe on local scales. Comparing the slopes of two extreme quantiles demonstrates that there are significant disparities in trends of cold and warm temperature extremes at many locations in Europe. At some locations the range of extreme cold and hot temperatures increases, while at other locations it decreases. These results suggest that at some locations both warm and cold extremes intensify which seems to be contradictory to the prevailing view of global warming in which both cold and warm temperatures are expected to increase. ©2015. American Geophysical Union. All Rights Reserved.

Pieger S.,University of Hamburg | Salman A.,Bharath University | Bidra A.S.,University of Connecticut Health Center
Journal of Prosthetic Dentistry | Year: 2014

Statement of problem Lithium disilicate is a relatively new and popular restorative material for esthetic and functional rehabilitations, but the evidence for clinical outcomes is not clear. Purpose The purpose of this systematic review was to analyze the short-term (1- to 5-year) and medium-term (5- to 10-year) survival rates of lithium disilicate single crowns and partial fixed dental prostheses. Material and methods An electronic search for articles in the English-language literature published between January 1998 and June 2013 was performed with the PubMed search engine. The specific search terms used were lithium disilicate, lithium silicate, IPS e max, IPS Empress, CAD CAM, pressed ceramic, monolithic, and bilayer. After applying predetermined inclusion and exclusion criteria, the definitive list of selected articles was suitable only for calculating the interval survival rate and cumulative survival rate. Results The electronic search resulted in 2033 titles. The systematic application of inclusion and exclusion criteria resulted in 12 clinical studies that addressed the clinical outcomes of lithium disilicate restorations. Of these, 2 were randomized controlled trials, 5 were prospective studies, 1 was a retrospective study, and 4 studies were descriptive in nature. All 12 studies reported on tooth-retained lithium disilicate restorations. The 2-year cumulative survival rate for single crowns was 100%, and the 5-year cumulative survival rate was 97.8%. The 2-year cumulative survival rate for fixed dental prostheses was 83.3%, and the 5-year cumulative survival rate was 78.1%. The cumulative survival rate over a 10-year period, primarily owing to data from 1 study, was 96.7% for single crowns and 70.9% for fixed dental prostheses. Conclusions For lithium disilicate single crowns, the existing evidence indicates excellent short-term survival rates, but the evidence for medium-term survival is limited. For lithium disilicate fixed dental prostheses, the evidence for short-term survival is fair, although limited, but the evidence for medium-term survival is not promising. The majority of failures in both types of restorations were reported in the posterior region. © 2014 by the Editorial Council for The Journal of Prosthetic Dentistry.

Jurgens T.P.,University of Hamburg | Leone M.,Headache Center
Cephalalgia | Year: 2013

Context: A variety of neuromodulatory approaches available today has broadened our therapeutic options significantly especially in drug refractory patients with chronic cluster headache and chronic migraine. Overview: It is a dynamic field with a current trend to non-invasive transcutaneous stimulation approaches. However, sound studies providing evidence for the widespread use of these novel approaches are sparse. For invasive approaches, occipital nerve stimulation is now widely considered the treatment of first choice in chronic trigeminal autonomic cephalgias and - with limitations - chronic migraine. Although equally effective, deep brain stimulation is considered second-line treatment in cluster headache because of its potentially life-threatening side effects. Most recently, stimulation of the sphenopalatine ganglion has also been shown to effectively abort acute cluster headache attacks. Interesting other upcoming approaches include transcutaneous supraorbital nerve stimulation and transcutaneous vagal nerve stimulation. Conclusion: Pearls and pitfalls of common invasive and non-invasive neuromodulatory approaches and open questions are summarised in this review along with recommendations for future studies. © 2013 International Headache Society.

Eibich P.,German Institute for Economic Research | Eibich P.,University of Oxford | Eibich P.,University of Hamburg
Journal of Health Economics | Year: 2015

This paper investigates the mechanisms behind the health effects of retirement. Using a Regression Discontinuity Design to exploit financial incentives in the German pension system for identification, I find that retirement improves subjective health status and mental health, while also reducing outpatient care utilization. I explore a wide range of health behaviors, time use, and effect heterogeneity as potential mechanisms. Relief from work-related stress and strain, increased sleep duration as well as more frequent physical exercise seem to be key mechanisms through which retirement affects health. © 2015 Elsevier B.V.

Eschenhagen T.,University of Hamburg | Eschenhagen T.,German Center for Cardiovascular Research | Mummery C.,Leiden University | Knollmann B.C.,Vanderbilt University
Cardiovascular Research | Year: 2015

One of the obstacles to a better understanding of the pathogenesis of human cardiomyopathies has been poor availability of heart-tissue samples at early stages of disease development. This has possibly changed by the advent of patient-derived induced pluripotent stem cell (hiPSC) from which cardiomyocytes can be derived in vitro. The main promise of hiPSC technology is that by capturing the effects of thousands of individual gene variants, the phenotype of differentiated derivatives of these cells will provide more information on a particular disease than simple genotyping. This article summarizes what is known about the 'human cardiomyopathy or heart failure phenotype in vitro', which constitutes the reference for modelling sarcomeric cardiomyopathies in hiPSC-derived cardiomyocytes. The current techniques for hiPSC generation and cardiac myocyte differentiation are briefly reviewed and the few published reports of hiPSC models of sarcomeric cardiomyopathies described. A discussion of promises and challenges of hiPSC-modelling of sarcomeric cardiomyopathies and individualized approaches is followed by a number of questions that, in the view of the authors, need to be answered before the true potential of this technology can be evaluated. © 2015 © The Author 2015. Published by Oxford University Press on behalf of the European Society of Cardiology.

Nalbach P.,Albert Ludwigs University of Freiburg | Eckel J.,Albert Ludwigs University of Freiburg | Thorwart M.,Albert Ludwigs University of Freiburg | Thorwart M.,University of Hamburg
New Journal of Physics | Year: 2010

We show that the quantum coherent transfer of excitations between biomolecular chromophores is strongly influenced by spatial correlations of environmental fluctuations. The latter are due either to propagating environmental modes or to local fluctuations with a finite localization length. A simple toy model of a single donor-acceptor pair with spatially separated chromophore sites allows one to investigate the influence of these spatial correlations on quantum coherent excitation transfer. The sound velocity of the solvent determines the wavelength of the environmental modes, which, in turn, has to be compared to the spatial distance of the chromophore sites. When the wavelength exceeds the distance between donor and acceptor sites, we find a strong suppression of decoherence. In addition, we consider two spatially separated donor-acceptor pairs under the influence of propagating environmental modes. Depending on their wavelengths fixed by the sound velocity of the solvent material, the spatial range of correlations may extend over typical interpair distances, which can lead to an increase in the decohering influence of the solvent. Surprisingly, this effect is counteracted by increasing temperature. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

Kuhn S.,Max Planck Institute for Human Development | Gallinat J.,Charite - Medical University of Berlin | Gallinat J.,University of Hamburg
Addiction Biology | Year: 2015

In the past decades, the Internet has become one of the most important tools to gather information and communicate with other people. Excessive use is a growing concern of health practitioners. Based on the assumption that excessive Internet use bears resemblance with addictive behaviour, we hypothesized alterations of the fronto-striatal network in frequent users. On magnetic resonance imaging scans of 62 healthy male adults, we computed voxel-based morphometry to identify grey matter (GM) correlates of excessive Internet use, assessed by means of the Internet Addiction Test (IAT) and functional connectivity analysis and amplitude of low-frequency fluctuation (ALFF) measures on resting state data to explore the functional networks associated with structural alterations. We found a significant negative association between the IAT score and right frontal pole GM volume (P-<-0.001, family wise error corrected). Functional connectivity of right frontal pole to left ventral striatum was positively associated with higher IAT scores. Furthermore, the IAT score was positively correlated to ALFF in bilateral ventral striatum. The alterations in the fronto-striatal circuitry associated with growing IAT scores could reflect a reduction of top-down modulation of prefrontal areas, in particular, the ability to maintain long-term goals in face of distraction. The higher activation of ventral striatum at rest may indicate a constant activation in the context of a diminished prefrontal control. The results demonstrate that excessive Internet use may be driven by neuronal circuits relevant for addictive behaviour. The Internet has become one of the most important tools to gather information and communicate with other people. Excessive use is a growing concern of health practitioners. We examined its neural correlates and found a negative association between the internet addiction test (IAT) score and right frontal pole grey matter volume. Functional connectivity of right frontal pole to left ventral striatum was positively associated with higher IAT scores and IAT score was positively correlated to ALFF in bilateral ventral striatum. © 2014 Society for the Study of Addiction.

Scannapieco E.,Arizona State University | Bruggen M.,University of Hamburg
Astrophysical Journal | Year: 2015

To better understand the nature of the multiphase material found in outflowing galaxies, we study the evolution of cold clouds embedded in flows of hot and fast material. Using a suite of adaptive mesh refinement simulations that include radiative cooling, we investigate both cloud mass loss and cloud acceleration under the full range of conditions observed in galaxy outflows. The simulations are designed to track the cloud center of mass, enabling us to study the cloud evolution at long disruption times. For supersonic flows, a Mach cone forms around the cloud, which damps the Kelvin-Helmholtz instability but also establishes a streamwise pressure gradient that stretches the cloud apart. If time is expressed in units of the cloud crushing time, both the cloud lifetime and the cloud acceleration rate are independent of cloud radius, and we find simple scalings for these quantities as a function of the Mach number of the external medium. A resolution study suggests that our simulations accurately describe the evolution of cold clouds in the absence of thermal conduction and magnetic fields, physical processes whose roles will be studied in forthcoming papers. © 2015. The American Astronomical Society. All rights reserved.

Dandri M.,University of Hamburg | Locarnini S.,Research and Molecular Development
Gut | Year: 2012

Chronic hepatitis B virus (HBV) infection remains a major health burden and the main risk factor for the development of hepatocellular carcinoma worldwide. However, HBV is not directly cytopathic and liver injury appears to be mostly caused by repeated attempts of the host's immune responses to control the infection. Recent studies have shown that the unique replication strategy adopted by HBV enables it to survive within the infected hepatocyte while complex virus-host interplays ensure the virus is able to fulfil its replication requirements yet is still able to evade important host antiviral innate immune responses. Clearer understanding of the host and viral mechanisms affecting HBV replication and persistence is necessary to design more effective therapeutic strategies aimed at improving the management of patients with chronic HBV infection to eventually achieve viral eradication. This article focuses on summarising the current knowledge of factors influencing the course of HBV infection, giving emphasis on the use of novel assays and quantitative serological and intrahepatic biomarkers as tools for predicting treatment response and disease progression.

Wilson J.B.,University of Otago | Peet R.K.,University of North Carolina at Chapel Hill | Dengler J.,University of Hamburg | Partel M.,University of Tartu
Journal of Vegetation Science | Year: 2012

Questions: The co-existence of high numbers of species has always fascinated ecologists, but what and where are the communities with the world records for plant species richness? The species-area relationship is among the best-known patterns in community ecology, but does it give a consistent global pattern for the most saturated communities, the global maxima? Location: The world. Methods: We assembled the maximum values recorded for vascular plant species richness for contiguous areas from 1 mm 2 up to 1 ha. We applied the power function to relate maximal richness to area and to make extrapolations to the whole Earth. Results: Only two community types contain global plant species maxima. The maxima at smaller spatial grain were from oligo- to meso-trophic, managed, semi-natural, temperate grasslands (e.g. 89 species on 1 m 2), those at larger grains were from tropical rain forests (e.g. 942 species on 1 ha). The maximum richness values closely followed a power function with z = 0.250: close to Preston's 'canonical' value of 0.262. There was no discernable difference between maxima using rooted presence (i.e. including only plants rooted in the plot) vs shoot presence (i.e. including any plant with physical cover over the plot). However, shoot presence values must logically be greater, with the curves flattening out at very small grain, and there is evidence of this from point quadrats. Extrapolating the curve to the terrestrial surface of the Earth gave a prediction of 219 204 vascular plant species, surprisingly close to a recent estimate of 275 000 actual species. Conclusions: Very high richness at any spatial grain is found only in two particular habitat/community types. Nevertheless, these high richness values form a very strong, consistent pattern, not greatly affected by the method of sampling, and this pattern extrapolates amazingly well. The records challenge ecologists to consider mechanisms of species co-existence, answers to the 'Paradox of the Plankton'. © 2012 International Association for Vegetation Science.

Grun A.-L.,University of Koblenz-Landau | Stemplewitz B.,University of Hamburg | Scheid P.,Central Institute of the Bundeswehr Medical Service Koblenz
Parasitology Research | Year: 2014

Several strains of free-living amoebae (FLA) belonging to the genus Acanthamoeba are able to cause a painful sight-threatening disease of the cornea designated as Acanthamoeba keratitis (AK). In this case report, a 22-year-old woman, wearer of soft contact lenses, was treated after the initial examination, and follow-up laboratory results led to the diagnosis of Acanthamoeba keratitis. The patient recovered under the targeted therapy, demonstrating that the acanthamoebae were the etiological agents of the keratitis in this case. The acanthamoebae belonged morphologically to group II. Genotyping of the causative Acanthamoeba strain based on sequences of the PCR amplimer ASA.S1 amplified from 18S ribosomal DNA by using the genus-specific primers JDP1 and JDP2 followed. The phylogenetic comparison of ASA.S1 confirmed that the isolated Acanthamoeba strain is closely related to genotype T13 supported by pairwise sequence identities of 97.1-98.0 % and bootstrap support of 980 replicates with reference sequences of genotype T13. These results regarding the Acanthamoeba keratitis-causing isolate KaBo expands the number of known pathogenic genotypes to 12. To our knowledge, this is the first report of a T13 Acanthamoeba genotype being associated with keratitis in humans. © 2014 Springer-Verlag.

The first and essential step in the process that generates the contents of awareness is the establishment of representational brain features-according to the NETofANs-model, this occurs through a process of multi-level self-organization and emergence in a "network of attractor-dominated networks of neurons" or NETofANs. We analyze how processes involving representational brain features can result in intelligent behaviors, including categorization of reality-features, conceptualization of percepts, existential-problem solving, imagination, and thought. The NETofANs-model explains representation and intentionality in terms of dynamical systems and thereby establishes a theoretical basis for the naturalization of semantics and the construction of semantic agents. © 2010 Elsevier B.V.

Dausmann K.H.,University of Hamburg
Journal of Zoology | Year: 2014

Heterothermy is an energy-saving strategy usually employed in response to environmental bottlenecks, which is common in almost all mammalian orders. Within the order primates, heterothermy has been physiologically confirmed only in the family Cheirogaleidae (Cheirogaleus, Microcebus, Allocebus, Mirza) of the Malagasy lemurs, and the southern lesser bushbaby (Galago moholi) of the family Galagonidae. These closely related species employ a spectrum of daily torpor, prolonged torpor and obligate hibernation under tropical, but nevertheless seasonal and energetically demanding conditions. There is a remarkable physiological flexibility in regard to their thermoregulatory adaptations not only between species of the same genera within one habitat, but also between populations of the same species, within populations and even within the same individual, permitting immediate responses in seasonal and unpredictable environments, and possibly aiding these species to master challenges of globally changing climatic conditions. Whereas heterothermy is a flexible, but regular seasonal response in the Cheirogaleidae, it is only used as a last emergency strategy in G. moholi. In the other primate species, there is either no or only anecdotal evidence of only minor reductions in metabolic rate, presumably rather reflecting pronounced circadian cycles in body temperature, or local heterothermy. Maybe because of their relatively high degree of sociality and larger body sizes, behavioural and ecological adaptations to seasonality are selected for in other primates. © 2014 The Zoological Society of London.

Kralj-Fiser S.,Slovenian Academy of science and Arts | Schuett W.,University of Hamburg
Animal Behaviour | Year: 2014

Research on animal personality variation has been burgeoning in the last 20 years but surprisingly few studies have investigated personalities in invertebrate species although they make up 98% of all animal species. Such lack of invertebrate studies might be due to a traditional belief that invertebrates are just 'minirobots'. Lately, studies highlighting personality differences in a range of invertebrate species have challenged this idea. However, the number of invertebrate species investigated still contrasts markedly with the effort that has been made studying vertebrates, which represent only a single subphylum. We describe how investigating proximate, evolutionary and ecological correlates of personality variation in invertebrates may broaden our understanding of personality variation in general. In our opinion, personality studies on invertebrates are much needed, because invertebrates exhibit a range of aspects in their life histories, social and sexual behaviours that are extremely rare or absent in most studied vertebrates, but that offer new avenues for personality research. Examples are complete metamorphosis, male emasculation during copulation, asexual reproduction, eusociality and parasitism. Further invertebrate personality studies could enable a comparative approach to unravel how past selective forces have driven the evolution of personality differences. Finally, we point out the advantages of studying personality variation in many invertebrate species, such as easier access to relevant data on proximate and ultimate factors, arising from easy maintenance, fast life cycles and short generation times. © 2014 The Association for the Study of Animal Behaviour.

Danshita I.,RIKEN | Mathey L.,University of Hamburg
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2013

We study the quantum phases of one-dimensional Bose-Fermi mixtures in optical lattices. Assuming repulsive interparticle interactions, equal mass, and unit total filling, we calculate the ground-state phase diagram by means of both the Tomonaga-Luttinger liquid theory and time-evolving block decimation method. We demonstrate the existence of a counterflow superfluid phase of polaron pairs, which are composite particles consisting of two fermions and two bosonic holes, in a broad range of the parameter space. We find that this phase naturally emerges in 174Yb-173Yb mixtures, realized in recent experiments, at low temperatures. © 2013 American Physical Society.

Bechtel B.,University of Hamburg
Remote Sensing | Year: 2015

Land surface temperature (LST) is an important parameter in various fields including hydrology, climatology, and geophysics. Its derivation by thermal infrared remote sensing has long tradition but despite substantial progress there remain limited data availability and challenges like emissivity estimation, atmospheric correction, and cloud contamination. The annual temperature cycle (ATC) is a promising approach to ease some of them. The basic idea to fit a model to the ATC and derive annual cycle parameters (ACP) has been proposed before but so far not been tested on larger scale. In this study, a new global climatology of annual LST based on daily 1 km MODIS/Terra observations was processed and evaluated. The derived global parameters were robust and free of missing data due to clouds. They allow estimating LST patterns under largely cloud-free conditions at different scales for every day of year and further deliver a measure for its accuracy respectively variability. The parameters generally showed low redundancy and mostly reflected real surface conditions. Important influencing factors included climate, land cover, vegetation phenology, anthropogenic effects, and geology which enable numerous potential applications. The datasets will be available at the CliSAP Integrated Climate Data Center pending additional processing. © 2015 by the authors.

Pantel K.,University of Hamburg | Speicher M.R.,Medical University of Graz
Oncogene | Year: 2016

Metastasis is a biologically complex process consisting of numerous stochastic events which may tremendously differ across various cancer types. Circulating tumor cells (CTCs) are cells that are shed from primary tumors and metastatic deposits into the blood stream. CTCs bear a tremendous potential to improve our understanding of steps involved in the metastatic cascade, starting from intravasation of tumor cells into the circulation until the formation of clinically detectable metastasis. These efforts were propelled by novel high-resolution approaches to dissect the genomes and transcriptomes of CTCs. Furthermore, capturing of viable CTCs has paved the way for innovative culturing technologies to study fundamental characteristics of CTCs such as invasiveness, their kinetics and responses to selection barriers, such as given therapies. Hence the study of CTCs is not only instrumental as a basic research tool, but also allows the serial monitoring of tumor genotypes and may therefore provide predictive and prognostic biomarkers for clinicians. Here, we review how CTCs have contributed to significant insights into the metastatic process and how they may be utilized in clinical practice. © 2016 Macmillan Publishers Limited All rights reserved.

Eden C.,University of Hamburg
Journal of Physical Oceanography | Year: 2015

Following a suggestion by Tailleux, a consistent formulation of internal energy, the first law of thermodynamics, and the thermodynamic potentials for an ocean in Boussinesq approximation with a nonlinear equation of state is given. A modification of the pressure work in the first law is the only necessary modification from which all thermodynamic potentials and thermodynamic relations follow in a consistent way. This treatment of thermodynamics allows for a closed and explicit formulation of conservation equations for dynamic and potential reservoirs of both enthalpy and internal energy, which differentiate approximately reversible from irreversible effects on internal energy, and allows for a formulation of a closed energy cycle on which energetically consistent ocean models can be based on. © 2015 American Meteorological Society.

Walker B.J.,Massachusetts Institute of Technology | Dorn A.,Massachusetts Institute of Technology | Dorn A.,University of Hamburg | Bulovic V.,Massachusetts Institute of Technology | Bawendi M.G.,Massachusetts Institute of Technology
Nano Letters | Year: 2011

J-aggregates are ordered clusters of coherently coupled molecular dyes,(1)and they have been used as light sensitizers in film photography due to their intense absorptions. Hybrid structures containing J-aggregates may also have applications in devices that require spectral specificity, such as color imaging or optical signaling.(2)However the use of J-aggregates in optoelectronic devices has posed a long-standing challenge(3, 4)due to the difficulty of controlling aggregate formation and the low charge carrier mobility of many J-aggregates in solid state. In this paper, we demonstrate a modular method to assemble three different cyanine J-aggregates onto CdSe nanowires, resulting in a photodetector that is color-sensitized in three specific, narrow absorption bands. Both the J-aggregate and nanowire device components are fabricated from solution and the sensitizing wavelength is switched from blue to red to green, using only solution-phase exchange of the J-aggregates on the same underlying device. © 2011 American Chemical Society.

Guse A.H.,University of Hamburg
Biochimica et Biophysica Acta - Proteins and Proteomics | Year: 2015

Abstract Nicotinamide adenine dinucleotide (NAD) has been known since a long period of time as co-factor of oxidoreductases. However, in the past couple of decades further roles have been assigned to NAD. Here, metabolism of NAD to the Ca2 + mobilizing second messengers cyclic adenosine diphosphoribose, nicotinic acid adenine dinucleotide phosphate and adenosine diphosphoribose is reviewed. Moreover, the mechanisms of Ca2 + mobilization by these adenine nucleotides and their putative target Ca2 + channels, ryanodine receptors and transient receptor potential channels are discussed. This article is part of a Special Issue entitled: Cofactor-dependent proteins: evolution, chemical diversity and bio-applications. © 2014 Elsevier B.V.

Liszkowski U.,University of Hamburg | Liszkowski U.,Max Planck Institute for Psycholinguistics
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2014

How do infants communicate before they have acquired a language? This paper supports the hypothesis that infants possess social- cognitive skills that run deeper than language alone, enabling them to understand others and make themselves understood. I suggested that infants, like adults, use two sources of extralinguistic information to communicate meaningfully and react to and express communicative intentions appropriately. In support, a review of relevant experiments demonstrates, first, that infants use information from preceding shared activities to tailor their comprehension and production of communication. Second, a series of novel findings from our laboratory shows that in the absence of distinguishing information from preceding routines or activities, infants use accompanying characteristics (such as prosody and posture) that mark communicative intentions to extract and transmit meaning. Findings reveal that before infants begin to speak they communicate in meaningful ways by binding preceding and simultaneous multisensory information to a communicative act. These skills are not only a precursor to language, but also an outcome of social-cognitive development and social experience in the first year of life. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Dorffling K.,University of Hamburg
Journal of Plant Growth Regulation | Year: 2015

Parallel to the discovery of auxin as a growth-promoting hormone in the first half of the last century, it became evident that inhibitors of auxin-induced cell elongation, seed germination and bud growth also existed in plants. Their activity was noticed first in more or less unspecific bioassays, and their natural function remained unknown for a long time. The introduction of paper chromatography in combination with bioassays enabled improved separation of plant extracts and identification of biologically active compounds. By means of these new techniques, a highly active growth inhibitory fraction named ‘inhibitor β’ was discovered in many plants. Evidence that this fraction seemed also to be involved in abscission processes resulted in the name ‘abscisin II’, whereas another research group that investigated the possible role of inhibitor β in bud dormancy proposed the name ‘dormin’. Great efforts were made to identify the chemical nature of the two compounds. In 1965, it was recognized that abscisin II and dormin possessed the same chemical structure, which received the name ‘abscisic acid’ (ABA). Soon afterwards the extraordinary role of ABA as a hormone involved in stress reactions and in seed maturation was discovered, whereas its suggested function in abscission and bud dormancy processes has not been well established until now. The name ABA is therefore not adequate with regard to the hormonal functions, but it is acceptable with regard to priority rules. © 2015, Springer Science+Business Media New York.

Stephenson U.M.,University of Hamburg
Acta Acustica united with Acustica | Year: 2010

Ray tracing (RT) and mirror image source methods (MISM), widely used in room acoustics and in computing noise propagation, fail naturally when diffraction becomes important, especially in 'free field' (cities). Therefore, the goal is to extend these methods by an edge diffraction module, also for higher orders. Known analytical approaches for the diffraction at a wedge may be combined with the MISM but are inefficient. A direct combination with RT is not possible as random emitted particles never pass edges exactly. In 1986, the author proposed a sound particle diffraction model based on Heisenbergs uncertainty relation (UR) introducing the concept of a 'deflection angle probability density function' (DAPDF) ('the closer the by-pass distance at an edge, the stronger the deflection effect'). This heuristic model had given very good agreements with the expected transfer functions of the half-infinite screen and the slit but has the deficit of a missing analytical derivation. To overcome this, the author tried to derive such a DAPDF from the known Fresnel-Kirchhoff theory of diffraction at the half-infinite screen. This succeeded by assuming that the energy flow around the edge is simply cut off by a vertical shift of the screen: the 'hypothesis of the shifted screen'. But this solution was published only very briefly and only in German 1993. It is the aim of this paper to present here for the first time the full derivation. The agreements at the screen are very good but the model fails at a slit (two edges), hence, cannot be modularized as desired. Meanwhile (in 2006 and 2007) the UR-based diffraction model performed some new promising results. The deficiencies and chances of the two models are discussed. © S. Hirzel Verlag.

The Na+-Mg2+-NO3 --SO4 2--H2O quaternary reciprocal system is an important subsystem of several natural brine types associated with nitrate deposits on earth (e.g. in the Atacama Desert), in atmospheric aerosols, in natural stone or building stones subjected to atmospheric pollution and in cave nitrates. We report on an ion interaction (Pitzer) model that is used to calculate activities and solubilities in this reciprocal system. Model parameterization is based on binary and ternary experimental data. New parameters are reported for Mg(NO3)2-H2O and the ternary systems Na+-Mg2+-NO3 --H2O and Mg2+-NO3 --SO4 2--H2O. We also report on the details of the model parameterization of the NaNO3-H2O binary. Calculated solubility diagrams of the full reciprocal system are compared to experimental data. In most cases the calculations are within the experimental uncertainty. Several important invariant points of the reciprocal system are calculated and the stability ranges of the various solids are discussed in detail. It is shown that both darapskite, Na3NO3SO4·H2O, and bloedite, Na2Mg(SO4)2·4H2O, have large stability fields in the reciprocal system at near ambient temperatures. This is in agreement with their common occurrence in nitrate deposits. © 2016 Elsevier B.V.

Boels R.,University of Hamburg
Journal of High Energy Physics | Year: 2010

In this article a first step is made towards the extension of Britto-Cachazo- Feng-Witten (BCFW) tree level on-shell recursion relations to integrands and integrals of scattering amplitudes to arbitrary loop order. Surprisingly, it is shown that the large BCFW shift limit of the integrands has the same structure as the corresponding tree level amplitude in any minimally coupled Yang-Mills theory in four or more dimensions. This implies that these integrands can be reconstructed from a subset of their 'single cuts'. The main tool is powercounting Feynman graphs in a special lightcone gauge choice employed earlier at tree level by Arkani-Hamed and Kaplan. The relation between shifts of integrands and shifts of its integrals is investigated explicitly at one loop. Two particular sources of discrepancy between the integral and integrand are identified related to UV and IR divergences. This is cross-checked with known results for helicity equal amplitudes at one loop. The nature of the on-shell residue at each of the single-cut singularities of the integrand is commented upon. Several natural conjectures and opportunities for further research present themselves. © 2010 SISSA.

Berger K.U.,University of Hamburg
Waste Management | Year: 2015

The Hydrologic Evaluation of Landfill Performance (HELP) model is the most widely applied model to calculate the water balance of cover and bottom liner systems for landfills. The paper summarizes the 30. year history of the model from HELP version 1 to HELP 3.95 D and includes references to the three current and simultaneously available versions (HELP 3.07, Visual HELP 2.2, and HELP 3.95 D). A sufficient validation is an essential precondition for the use of any model in planning. The paper summarizes validation approaches for HELP 3 focused on cover systems in the literature. Furthermore, measurement results are compared to simulation results of HELP 3.95 D for (1) a test field with a compacted clay liner in the final cover of the landfill Hamburg-Georgswerder from 1988 to 1995 and (2) a test field with a 2.3. m thick so-called water balance layer on the landfill Deetz near Berlin from 2004 to 2011. On the Georgswerder site actual evapotranspiration was well reproduced by HELP on the yearly average as well as in the seasonal course if precipitation data with 10% systematic measurement errors were used. However, the increase of liner leakage due to the deterioration of the clayey soil liner was not considered by the model. On the landfill Deetz HELP overestimated largely the percolation through the water balance layer resulting from an extremely wet summer due to an underestimation of the water storage in the layer and presumably also due to an underestimation of the actual evapotranspiration. Finally based on validation results and requests from the practice, plans for improving the model to a future version HELP 4 D are described. © 2015 Elsevier Ltd.

Horst A.K.,University of Hamburg
Blood | Year: 2014

In this issue of Blood, Alshahrani et al demonstrate that carcinoembryonic antigen-related cell adhesion molecule 2 (CEACAM2) is expressed on platelets and negatively regulates the collagen receptor glycoprotein (GP) VI-FcRγ chain and C-type lectin-like receptor 2 (CLEC-2)-mediated platelet activation.1 © 2014 by The American Society of Hematology.

Holig C.,University of Hamburg | Berti S.,Johannes Gutenberg University Mainz
Brain Research | Year: 2010

Attention is controlled by the interplay of sensory input and top-down processes. We compared attentional control processes during task switching and reorientation after distraction. The primary task was to discriminate laterally and centrally presented tones; these stimuli were composed of a frequent standard or an infrequent deviant pitch. In the distraction condition, pitch was irrelevant and could be ignored. In the switch condition, pitch changes were relevant: whenever a deviant tone was presented, participants had to discriminate its pitch and not its direction. The task in standard trials remained unchanged. In both conditions, deviants elicited mismatch negativity (MMN), P3a, P3b, and reorienting negativity (RON). We, therefore, suggest that distraction and switching are triggered by the same system of attentional control. In addition, remarkable differences were observable between the two conditions: In the switch condition the MMN was followed by a more pronounced N2b and P3a. The differences between these components support the idea that in the distraction condition, a switch of attention is only initiated but not completely performed. © 2010 Elsevier B.V.

Finsterbusch J.,University of Hamburg | Finsterbusch J.,University of Lubeck
Journal of Magnetic Resonance Imaging | Year: 2010

Purpose: To demonstrate the feasibility of two-dimensional selective radio frequency (2DRF) excitations for fast-spin-echo imaging of inner fields-of-view (FOVs) in order to shorten acquisitions times, decrease RF energy deposition, and reduce image blurring. Materials and Methods: Fast-spin-echo images (in-plane resolution 1.0 x 1.0 mm2 or 0.5 x 1.0 mm2) of inner FOVs (40 mm, 16 mm oversampling) were obtained in phantoms and healthy volunteers on a 3 T whole-body MR system using blipped-planar 2DRF excitations. Results: Positioning the unwanted side excitations in the blind spot between the image section and the slice stack to measure yields minimum 2DRF pulse durations (about 6 msec) that are compatible with typical echo spacings of fast-spin-echo acquisitions. For the inner FOVs, the number of echoes and refocusing RF pulses is considerably reduced which compared to a full FOV (182 mm) reduces the RF energy deposition by about a factor of three and shortens the acquisition time, e.g., from 39 seconds to 12 seconds for a turbo factor of 15 or from 900 msec to 280 msec for a single-shot acquisition, respectively. Furthermore, image blurring occurring for high turbo factors as in single-shot acquisitions is considerably reduced yielding effectively higher in-plane resolutions. Conclusion: Inner-FOV acquisitions using 2DRF excitations may help to shorten acquisitions times, ameliorate image blurring, and reduce specific absorption rate (SAR) limitations of fast-spin-echo (FSE) imaging, in particular at higher static magnetic fields. © 2010 Wiley-Liss, Inc.

Zahn M.,University of Reading | Zahn M.,Helmholtz Center Geesthacht | Von Storch H.,Helmholtz Center Geesthacht | Von Storch H.,University of Hamburg
Nature | Year: 2010

Every winter, the high-latitude oceans are struck by severe storms that are considerably smaller than the weather-dominating synoptic depressions. Accompanied by strong winds and heavy precipitation, these often explosively developing mesoscale cyclones-termed polar lows-constitute a threat to offshore activities such as shipping or oil and gas exploitation. Yet owing to their small scale, polar lows are poorly represented in the observational and global reanalysis data often used for climatological investigations of atmospheric features and cannot be assessed in coarse-resolution global simulations of possible future climates. Here we show that in a future anthropogenically warmed climate, the frequency of polar lows is projected to decline. We used a series of regional climate model simulations to downscale a set of global climate change scenarios from the Intergovernmental Panel of Climate Change. In this process, we first simulated the formation of polar low systems in the North Atlantic and then counted the individual cases. A previous study using NCEP/NCAR re-analysis data revealed that polar low frequency from 1948 to 2005 did not systematically change. Now, in projections for the end of the twenty-first century, we found a significantly lower number of polar lows and a northward shift of their mean genesis region in response to elevated atmospheric greenhouse gas concentration. This change can be related to changes in the North Atlantic sea surface temperature and mid-troposphere temperature; the latter is found to rise faster than the former so that the resulting stability is increased, hindering the formation or intensification of polar lows. Our results provide a rare example of a climate change effect in which a type of extreme weather is likely to decrease, rather than increase. © 2010 Macmillan Publishers Limited. All rights reserved.

Tellinghuisen J.,Vanderbilt University | Spiess A.-N.,University of Hamburg
Analytical Biochemistry | Year: 2014

New methods are used to compare seven qPCR analysis methods for their performance in estimating the quantification cycle (Cq) and amplification efficiency (E) for a large test data set (94 samples for each of 4 dilutions) from a recent study. Precision and linearity are assessed using chi-square (χ2), which is the minimized quantity in least-squares (LS) fitting, equivalent to the variance in unweighted LS, and commonly used to define statistical efficiency. All methods yield Cqs that vary strongly in precision with the starting concentration N0, requiring weighted LS for proper calibration fitting of Cq vs log(N 0). Then χ2 for cubic calibration fits compares the inherent precision of the Cqs, while increases in χ2 for quadratic and linear fits show the significance of nonlinearity. Nonlinearity is further manifested in unphysical estimates of E from the same Cq data, results which also challenge a tenet of all qPCR analysis methods - that E is constant throughout the baseline region. Constant-threshold (Ct) methods underperform the other methods when the data vary considerably in scale, as these data do. © 2013 Elsevier B.V. All rights reserved.

Grieger D.,International School for Advanced Studies | Lechermann F.,University of Hamburg
Physical Review B - Condensed Matter and Materials Physics | Year: 2014

The archetypical strongly correlated Mott-phenomena compound V2O3 is known to show a paramagnetic metal-insulator transition driven by doping with chromium atoms and/or (negative) pressure. Via charge self-consistent density-functional theory+dynamical mean-field theory calculations we demonstrate that these two routes cannot be understood as equivalent. An explicit description of Cr-doped V2O3 by means of supercell calculations and the virtual crystal approximation is performed. Introducing chromium's additional electron to the system is shown to modify the overall many-body electronic structure substantially. Chromium doping increases electronic correlations which in addition induce charge transfers between Cr and the remaining V ions. Thereby the transition-metal orbital polarization is increased by the electron doping, in close agreement with experimental findings. © 2014 American Physical Society.

Ide T.,University of Hamburg
Global Environmental Change | Year: 2015

This study addresses the question why intergroup conflicts over scarce, renewable resources in peripheral areas of the global South escalate into violence. In order to do so, twenty cases of such conflicts, seven of which turned violence, are analyzed. The method of fuzzy-set qualitative comparative analysis is used in order to bridge the gap between quantitative and qualitative accounts in the field and to detect patterns of conjunctural causation. In theoretical terms, structural conditions (negative othering and high power differences between the conflict parties) and triggering conditions (external resource appropriation and recent political change) of a violent escalation of renewable resource conflicts are distinguished. The empirical results as well as various robustness checks and comparisons with individual cases suggest that the simultaneous presence of negative othering, low power differences and recent political change is a sufficient condition for the violent escalation of conflicts over scarce renewable resources. I conclude that research on socio-environmental conflicts should pay more attention to conjunctural causation, local power differences and qualitatively different forms of conflict and political change. © 2015 The Authors. Published by Elsevier Ltd.

Sarkissian G.,University of Hamburg
International Journal of Modern Physics A | Year: 2010

We perform canonical quantization of the WZW model with defects and permutation branes. We establish symplectomorphism between phase space of WZW model with N defects on cylinder and phase space of ChernSimons theory on annulus times R with N Wilson lines, and between phase space of WZW model with N defects on strip and ChernSimons theory on disk times R with N + 2 Wilson lines. We obtained also symplectomorphism between phase space of the N-fold product of the WZW model on strip with boundary conditions specified by permutation branes, and phase space of ChernSimons theory on sphere times R with N holes and two Wilson lines. © 2010 World Scientific Publishing Company.

Marini C.,University of Hamburg | Frankignoul C.,University Pierre and Marie Curie
Climate Dynamics | Year: 2014

The link between the Atlantic Multidecadal Oscillation (AMO) and low-frequency changes of the Atlantic Meridional Overturning Circulation (AMOC) is investigated in three historical and five control simulations with different climate models. An AMOC intensification is followed by a positive AMO phase in each case, but the time lag and the strength of the AMO-AMOC link depend on the model and the type of simulation. In historical simulations, the link is sensitive to the method used to remove the influence of external and anthropogenic forcing from the sea surface temperature (SST) before defining the AMO. Subtracting the regression onto the global mean SST leads to better correlations between the AMO and the AMOC than linear or quadratic detrending, or removing the global mean SST, but a dynamical filter based on linear inverse modeling (LIM) yields even slightly higher correlations. The LIM filter, which decomposes the SST field into non-orthogonal normal modes that may have a physical interpretation, allows investigating whether removing Pacific links from SST improves the AMOC-AMO correlation. In several cases, there is a small improvement when removing the links to the El Niño Southern Oscillation, but the correlation becomes weaker in one historical simulation, so no firm conclusion can be drawn. Additionally removing the modes associated with the Pacific decadal variability strongly degrades the representation of AMOC changes by the AMO in one model, and it tends to reduce the AMOC-AMO correlation in most others, reflecting the strong relation between the Pacific and the Atlantic at decadal scales. The LIM-based filter is finally applied to observed SSTs, confirming that the AMO amplitude is smaller and its recent positive phase weaker than when the global effects are represented by a linear trend. When the global signal is removed, the observed AMO leads the Pacific Decadal Oscillation, but does not significantly lag it, as suggested earlier, stressing the need to carefully remove global changes when investigating low-frequency interbasin connections. © 2013 Springer-Verlag Berlin Heidelberg.

Bharucha A.,University of Hamburg | Heinemeyer S.,Institute Fisica Of Cantabria | von der Pahlen F.,Institute Fisica Of Cantabria
European Physical Journal C | Year: 2013

We re-assess the exclusion limits on the parameters describing the supersymmetric (SUSY) electroweak sector of the MSSM obtained from the search for direct chargino-neutralino production at the LHC. We start from the published limits obtained for simplified models, where for the case of heavy sleptons the relevant branching ratio, BR(χ̃2 0 → χ̃1 0), is set to one. We show how the decay mode χ̃2 0 → χ̃1 0, which cannot be neglected in any realistic model once kinematically allowed, substantially reduces the excluded parameter region. We analyze the dependence of the excluded regions on the phase of the gaugino soft SUSY-breaking mass parameter, M1, on the mass of the light scalar tau, mτ1, on tanβ as well as on the squark and slepton mass scales. Large reductions in the ranges of parameters excluded can be observed in all scenarios. The branching ratios of charginos and neutralinos are evaluated using a full NLO calculation for the complex MSSM. The size of the effects of the NLO calculation on the exclusion bounds is investigated. We furthermore assess the potential reach of the experimental analyses after collecting 100 fb-1 at the LHC running at 13 TeV. © 2013 Springer-Verlag Berlin Heidelberg and Società Italiana di Fisica.

Albino S.,University of Hamburg
Reviews of Modern Physics | Year: 2010

The description of inclusive production of single unpolarized light hadrons using fragmentation functions in the framework of the factorization theorem is reviewed. The factorization of observables into perturbatively calculable quantities and these universal fragmentation functions are summarized and some improvements beyond the standard fixed order approach are discussed. The extraction of fragmentation functions for light charged (π⊃±, K⊃±, and p.p̄) and neutral (KS0 and Λ/ Λ̄) hadrons using these theoretical tools is discussed through global fits to experimental data from reactions at various colliders, in particular from accurate e⊃+ e⊃- reactions at the Large Electron-Position Collider (LEP), and the subsequent successful predictions of other experimental data, such as data gathered at Hadron Electron Ring Accelerator (HERA), the Tevatron, and the Relativistic Heavy Ion Collider (RHIC), from these fitted fragmentation functions as allowed by factorization universality. These global fits also impose competitive constraints on αs (MZ). Emphasis is placed on the need for accurate data from pp (p̄) and ep reactions in which the hadron species is identified in order to constrain the separate fragmentation functions of the gluon and each quark flavor for each hadron species. © 2010 The American Physical Society.

Bader R.,University of Hamburg
Journal of the Acoustical Society of America | Year: 2010

A method for reconstructing a pressure field at the surface of a radiating body or source is presented using recording data of a microphone array. The radiation is assumed to consist of many spherical radiators, as microphone positions are present in the array. These monopoles are weighted using a parameter α, which broadens or narrows the overall radiation directivity as an effective and highly intuitive parameter of the radiation characteristics. A radiation matrix is built out of these weighted monopole radiators, and for different assumed values of α, a linear equation solver reconstructs the pressure field at the body's surface. It appears that from these many arbitrary reconstructions, the correct one minimizes the reconstruction energy. The method is tested, localizing the radiation points of a Balinese suling flute, reconstructing complex radiation from a duff frame drum, and determining the radiation directivity for the first seven modes of an Usbek tambourine. Stability in terms of measurement noise is demonstrated for the plain method, and additional highly effective algorithm is added for a noise level up to 0 dB. The stability of α in terms of minimal reconstruction energy is shown over the whole range of possible values for α. Additionally, the treatment of unwanted room reflections is discussed, still leading to satisfactory results in many cases. © 2010 Acoustical Society of America.

Boels R.H.,University of Hamburg | O'Connell D.,Niels Bohr Institute
Journal of High Energy Physics | Year: 2012

We provide simple superspaces based on a formulation of spinor helicity in general even dimensions. As a distinguishing feature these spaces admit a fermionic super-momentum conserving delta function solution to the on-shell supersymmetry Ward identities. Using these solutions, we present beautifully simple formulae for the complete three, four and five point superamplitudes in maximal super Yang-Mills theory in eight dimensions, and for the three and four point superamplitudes in ten dimensional type IIB super-gravity. In addition, we discuss the exceptional kinematics of the three point amplitude, and the supersymmetric spinorial BCFW recursion, in general dimensions. © 2012 SISSA.

Janka G.E.,University of Hamburg
Annual Review of Medicine | Year: 2012

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening syndrome in which an uncontrolled and ineffective immune response, triggered in most cases by infectious agents, leads to severe hyperinflammation. Familial forms of HLH (FHL), which are increasingly found also in adolescents and adults, are due to genetic defects leading to impaired function of natural killer cells and cytotoxic T cells. These mutations occur either in the perforin gene or in genes important for the exocytosis of cytotoxic granules. Cytotoxic granules contain perforin and granzymes, which induce apoptosis upon entering (infected) target cells. Additionally, perforin is important for the downregulation of the immune response. Acquired forms of HLH are encountered in association with (usually) viral infections, autoinflammatory/autoimmune diseases, malignant diseases, and acquired immune deficiency states (e.g., after organ transplantation). Treatment of HLH includes immune-suppressive and immune-modulatory agents, cytostatic drugs, and biological response modifiers. For patients with FHL, stem cell transplantation is indicated and can be curative. © 2012 by Annual Reviews. All rights reserved.

Stockfleth E.,TU Berlin | Meyer T.,University of Hamburg
Expert Opinion on Biological Therapy | Year: 2012

Introduction: Sinecatechins is a standardized extract of green tea leaves, containing a mixture of catechin compounds. The 15% ointment has been approved for the topical treatment of condylomata acuminata (CA), caused by particular human papillomaviruses (HPV), mainly HPV types 6 and 11. Objective: To update the use of sinecatechins for treatment of CA and to describe possible mechanisms involved in the mode of action. Areas covered: The clearance rate of wart lesions after treatment with sinecatechins is similar to other topically applied drugs, like imiquimod and podophyllotoxin, but recurrences are seen less frequently after treatment with sinecatechins. The molecular mode of action underlying the clinical efficacy has yet not been characterized, but the following properties are likely to be involved in the regression of genital warts: activation of cellular immune reactions, induction of cell cycle arrest and apoptosis, inhibition of HPV gene expression. Expert opinion: Sinecatechins is a safe and effective treatment option for CA. Due to the variety of molecular activities of catechins the product has great potential for application to other viral and tumor lesions in the future. © 2012 Informa UK, Ltd.

Menzel M.-P.,University of Hamburg
Regional Studies | Year: 2013

Menzel M.-P. Interrelating dynamic proximities by bridging, reducing and producing distances, Regional Studies. The proximity concept explains the spatiality of relations and innovations with various dimensions of proximity. The paper adapts this framework to the processes of change. It integrates the interrelations between different dynamics into the nomenclature of proximity and distance. Three dynamics are proposed that both interfere with and enable interaction: learning, connecting and moving. These dynamics cause changes in cognitive, network and spatial proximity. Using these dynamics, two arguments are introduced as the basis for a concept of dynamic proximity: (1) proximity in one dimension enables interaction despite distance in other dimensions; and (2) reducing distance at the dyadic level produces distance as externality. © 2013 © 2013 Regional Studies Association.

Yagi J.,University of Hamburg
Journal of High Energy Physics | Year: 2012

We argue that the six-dimensional (2, 0) superconformal theory defined on M × C, with M being a four-manifold and C a Riemann surface, can be twisted in a way that makes it topological on M and holomorphic on C. Assuming the existence of such a twisted theory, we show that its chiral algebra contains aW-algebra whenM = ℝ 4, possibly in the presence of a codimension-two defect operator supported on ℝ 2 × C ⊂ M × C. We expect this structure to survive the Ω-deformation. © 2012 SISSA.

Hasenkamp J.,University of Hamburg
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2012

Current observations of the cosmic microwave background could confirm an increase in the radiation energy density after primordial nucleosynthesis but before photon decoupling. We show that, if the gravitino problem is solved by a light axino, dark (decoupled) radiation emerges naturally in this period leading to a new upper bound on the reheating temperature T R≲10 11GeV. In turn, successful thermal leptogenesis might predict such an increase. The Large Hadron Collider could endorse this opportunity. At the same time, axion and axino can naturally form the observed dark matter. © 2011 Elsevier B.V.

Rummel M.,University of Hamburg | Westphal A.,German Electron Synchrotron
Journal of High Energy Physics | Year: 2012

We derive a suffcient condition for realizing meta-stable de Sitter vacua with small positive cosmological constant within type IIB string theory ux compactifications with spontaneously broken supersymmetry. There are a number of lamp post constructions of de Sitter vacua in type IIB string theory and supergravity. We show that one of them | the method of Kähler uplifting' by F-terms from an interplay between nonperturbative effects and the leading α′-correction | allows for a more general parametric understanding of the existence of de Sitter vacua. The result is a condition on the values of the ux induced superpotential and the topological data of the Calabi-Yau compacti fication, which guarantees the existence of a meta-stable de Sitter vacuum if met. Our analysis explicitly includes the stabilization of all moduli, i.e. the Kahler, dilaton and complex structure moduli, by the interplay of the leading perturbative and non-perturbative effects at parametrically large volume.

Talke K.,University of Hamburg | Salomo S.,Technical University of Denmark | Kock A.,TU Berlin
Journal of Product Innovation Management | Year: 2011

A firm's strategic innovation orientation, which is aimed at discovering and satisfying emerging customer needs with novel technological solutions, has repeatedly been shown to be crucial for firm innovativeness and firm performance. Despite its apparent importance, relatively little research has addressed antecedents of a firm's strategic orientation that help explain heterogeneity in innovation strategies across firms. Especially the influence of top management teams (TMT) should be critical, since innovation strategies are shaped at the top management level. Building on the theory of upper echelon, this study investigates how TMT characteristics affect a firm's strategic innovation orientation, and how this relates to innovation outcomes and firm performance. Hypotheses are tested on a sample of goods manufacturers using a combination of survey data, document analysis, and objective capital market data for firm performance. Results indicate that TMT diversity, measured as heterogeneity in educational, functional, industry, and organizational background, has a strong positive effect on a firm's innovation orientation. A strong proactive focus on emerging customer needs and on novel technologies then lead to a portfolio of new products with higher market newness and technology newness, which both increase firm performance. The results therefore emphasize the importance of TMT characteristics as antecedent for innovation strategy and innovation outcomes. © 2011 Product Development & Management Association.

Talke K.,University of Hamburg | O'Connor G.C.,Rensselaer Polytechnic Institute
Journal of Product Innovation Management | Year: 2011

This paper seeks to uncover the specific message content that facilitates the diffusion of industrial innovations. Diffusion theory specifies that innovation adoption is only likely to occur when a potential customer has positive perceptions of the new product's attributes. Hence, it seems intuitive that firms should use these attributes as message content when launching a new industrial product. But the question of which message content is actually used by firms, and how this impacts new product performance has not been addressed in the literature. Referring to this gap, the authors propose a model of three message content types: usability information, technical information, and financial information. Each of these information types is designed to mitigate a set of perceived risks that consumers may experience in the decision to adopt a new industrial product. Level of product innovativeness is considered as well, given its likely differential impact on the effectiveness of the specific message content used. The model is tested with 112 new industrial products using a multiple informant approach. Generally, the findings support the suggestion that using innovation attributes as message content can be effective when launching a new industrial product, but they behave differently from one another and differently in the moderated context. While usability information and financial information were found to be effective in impacting performance, technical information was found to be counter-effective. Concerning the moderating influence of product innovativeness, results indicate that usability information is of specific importance when launching a highly innovative product. Financial details, however, become less important. © 2011 Product Development & Management Association.

Bharucha A.,University of Hamburg
Journal of High Energy Physics | Year: 2012

We calculate the leading-twist O(α s 2β 0) corrections to the B → π transition form factor f+(0) in light-cone sum rules. We find that, as expected, there is a cancellation between the O(α s 2β 0) corrections to f Bf+(0) and the large corresponding corrections to f B, calculated in QCD sum rules. This suggests the insensitivity of the form factors calculated in the light-cone sum rules approach to this source of radiative corrections. We further obtain an improved determination of the CKM matrix element |V ub|, using latest results from BaBar and Belle for f+(0)|V ub|. © SISSA 2012.

Boels R.H.,University of Hamburg
Journal of High Energy Physics | Year: 2012

On-shell superspaces and associated spinor helicity techniques give an efficient formulation of the Ward identities of on-shell supersymmetry for scattering amplitudes and supply tools to construct their solutions. Based on these techniques in this paper the general solutions of the Ward identities are presented for three particle scattering amplitudes with one, two or three massive legs for simple supersymmetry in ten and eight dimensions. It is shown in examples how these solutions may be used to obtain concrete amplitudes for the closed (IIB) and open superstring in a flat background. Explicit results include all three point amplitudes with one massive leg whose functional form is shown to be dictated completely by super-Poincare symmetry. The resulting surprisingly simple series only involves massive superfields labelled by completely symmetric little group representations. The extension to more general explicit three and higher point amplitudes in string theory is initiated. In appendices the field content of the fundamental massive superfields of the open and closed superstring are listed in terms of the Dynkin labels of a variety of groups which may be of independent interest. © 2012 SISSA.

Walther Y.M.,Swedish University of Agricultural Sciences | Mollmann C.,University of Hamburg
ICES Journal of Marine Science | Year: 2014

An ecosystem approach to management (EAM) aims to secure a healthy ecosystem along with sustainable use of its goods and services. Although the main principles of EAM are agreed upon and desirable, wider implementation of EAM is still a challenge. The difficulties stem from unclear definition and communication of the EAM, lack of routines or protocols to develop ecosystem-based advice, inappropriate institutional structures, and communication issues between scientists, advisers, and managers. Integrated ecosystem assessment (IEA) is an instrument that has proven to help in the implementation of EAM. For successful implementation of EAM and IEA in the European regional seas context, an international forum is required that develops tailor-made EAM tools specific to the different regional ecosystems to overcome fragmented national strategies. We describe a multinational peer network of working groups developed within the International Council for the Exploration of the Sea (ICES) under the auspice of Science Steering Group on Regional Sea Programmes. Available is a wealth of data, expertise, scientific methods, and models for each regional sea. This network can be instrumental in advancing IEA for the implementation of EAM in the North Atlantic seas. © 2014 International Council for the Exploration of the Sea. All rights reserved.

Santer R.,University of Hamburg | Calado J.,New University of Lisbon
Clinical Journal of the American Society of Nephrology | Year: 2010

Four members of two glucose transporter families, SGLT1, SGLT2, GLUT1, and GLUT2, are differentially expressed in the kidney, and three of them have been shown to be necessary for normal glucose resorption from the glomerular filtrate. Mutations in SGLT1 are associated with glucose-galactose malabsorption, SGLT2 with familial renal glucosuria (FRG), and GLUT2 with Fanconi-Bickel syndrome. Patients with FRG have decreased renal tubular resorption of glucose from the urine in the absence of hyperglycemia and any other signs of tubular dysfunction. Glucosuria in these patients can range from <1 to >150 g/1.73 m2 per d. The majority of patients do not seem to develop significant clinical problems over time, and further description of specific disease sequelae in these individuals is reviewed. SGLT2, a critical transporter in tubular glucose resorption, is located in the S1 segment of the proximal tubule, and, as such, recent attention has been given to SGLT2 inhibitors and their utility in patients with type 2 diabetes, who might benefit from the glucose-lowering effect of such compounds. A natural analogy is made of SGLT2 inhibition to observations with inactivating mutations of SGLT2 in patients with FRG, the hereditary condition that results in benign glucosuria. This review provides an overview of renal glucose transport physiology, FRG and its clinical course, and the potential of SGLT2 inhibition as a therapeutic target in type 2 diabetes. Copyright © 2010 by the American Society of Nephrology.

Stephan B.,University of Hamburg
Environmental Politics | Year: 2012

Creating a mechanism for reducing emissions from deforestation and degradation (REDD+) in tropical developing countries has become, from 2005 onward, a central element in international climate protection discourse. The goal is to create financial incentives for forest protection by making avoided deforestation a tradable good that can be sold on the carbon market or to government funds. A discourse-analytical perspective on the process of commodification and market creation is developed in order to assess how avoided deforestation is being made tradable. Going beyond existing approaches, such a perspective enables us to highlight the contestedness and contingency of the commodification and market creation process. The extent to which on-going qualification and commensuration practices can result in a disentanglement of avoided deforestation as tradable good is discussed, and one of the consequences of a successful commodification of avoiding deforestation - the carbonification of forests - is highlighted. © 2012 Copyright Taylor and Francis Group, LLC.

Stephan B.,University of Hamburg | Paterson M.,University of Ottawa
Environmental Politics | Year: 2012

This overview of the existing political analysis of carbon markets identifies three broad strands in the literature. The first is concerned with the processes by which particular carbon market schemes are established. The second focuses on the role of particular actors in the creation of carbon markets. The third strand assesses carbon markets on efficiency, legitimacy or justice grounds. This existing literature is contrasted with the framework developed by the contributions to this volume. Broadly drawing on constructivist and poststructuralist approaches, the carbon economy is deconstructed, its history scrutinised and the practices and technologies that have been used to bring these markets into being are highlighted. Thus it is demonstrated that politics is not limited to the policy process leading up to the decision to implement an emissions trading scheme or offset mechanism, but is also present in the forms of knowledge claims that underpin these markets, as well as the various daily practices that constitute them. © 2012 Copyright Taylor and Francis Group, LLC.

Sensory systems processing information from the environment rely on precisely formed and refined neuronal networks that build maps of sensory receptor epithelia at different subcortical and cortical levels. These sensory maps share similar principles of function and emerge according to developmental processes common in visual, somatosensory and auditory systems. Whereas molecular cues set the coarse organization of cortico-subcortical topography, its refinement is known to succeed under the influence of experience-dependent electrical activity during critical periods. However, coordinated patterns of activity synchronize the cortico-subcortical networks long before the meaningful impact of environmental inputs on sensory maps. Recent studies elucidated the cellular and network mechanisms underlying the generation of these early patterns of activity and highlighted their similarities across species. Moreover, the experience-independent activity appears to act as a functional template for the maturation of sensory networks and cortico-subcortical maps. A major goal for future research will be to analyze how this early activity interacts with the molecular cues and to determine whether it is permissive or rather supporting for the establishment of sensory topography. © 2010 Elsevier B.V.

Kuhn S.,Max Planck Institute for Human Development | Gallinat J.,Charite - Medical University of Berlin | Gallinat J.,University of Hamburg
JAMA Psychiatry | Year: 2014

IMPORTANCE Since pornography appeared on the Internet, the accessibility, affordability, and anonymity of consuming visual sexual stimuli have increased and attracted millions of users. Based on the assumption that pornography consumption bears resemblance with reward-seeking behavior, novelty-seeking behavior, and addictive behavior, we hypothesized alterations of the frontostriatal network in frequent users. OBJECTIVE To determine whether frequent pornography consumption is associated with the frontostriatal network. DESIGN, SETTING, AND PARTICIPANTS In a study conducted at the Max Planck Institute for Human Development in Berlin, Germany, 64 healthy male adults covering a wide range of pornography consumption reported hours of pornography consumption per week. Pornography consumption was associated with neural structure, task-related activation, and functional resting-state connectivity. MAIN OUTCOMES AND MEASURES Gray matter volume of the brainwas measured by voxel-based morphometry and resting state functional connectivity was measured on 3-T magnetic resonance imaging scans. RESULTS We found a significant negative association between reported pornography hours per week and gray matter volume in the right caudate (P < .001, corrected for multiple comparisons) as well as with functional activity during a sexual cue-reactivity paradigm in the left putamen (P < .001). Functional connectivity of the right caudate to the left dorsolateral prefrontal cortex was negatively associated with hours of pornography consumption. CONCLUSIONS AND RELEVANCE The negative association of self-reported pornography consumption with the right striatum (caudate) volume, left striatum (putamen) activation during cue reactivity, and lower functional connectivity of the right caudate to the left dorsolateral prefrontal cortex could reflect change in neural plasticity as a consequence of an intense stimulation of the reward system, together with a lower top-down modulation of prefrontal cortical areas. Alternatively, it could be a precondition that makes pornography consumption more rewarding. © 2014 American Medical Association. All rights reserved.

Schwarzenbach H.,University of Hamburg
Drug Testing and Analysis | Year: 2011

To achieve success in sports, many athletes consume doping substances, such as anabolic androgenic steroids and growth hormones, and ignore the negative influence of these drugs on their health. Apart from the unethical aspect of doping in sports, it is essential to consider the tremendous risk it represents to their physical condition. The abuse of pharmaceuticals which improve athletic performance may alter the expression of specific genes involved in muscle and bone metabolism by epigenetic mechanisms, such as DNA methylation and histone modifications. Moreover, excessive and relentless training to increase the muscle mass, may also have an influence on the health of the athletes. This stress releases neurotransmitters and growth factors, and may affect the expression of endogenous genes by DNA methylation, too. This paper focuses on the relationship between epigenetic mechanisms and sports, highlights the potential consequences of abuse of doping drugs on gene expression, and describes methods to molecularly detect epigenetic changes of gene markers reflecting the physiological or metabolic effects of doping agents. © 2011 John Wiley & Sons, Ltd.

One core element of reflexive governance is the reflexive capacity-building of actors involved in governance networks. A wider range of actors have to be empowered to understand and improve governance arrangements in order to create second-order reflexivity. As a contribution to this challenge, a heuristic framework is developed from two complementary approaches to reflexive governance: the multi-level perspective (MLP) and the conflict-orientated understanding (COU) approach. The new framework is applied to two case studies - water management and long-term climate adaptation - where it has helped to develop a participatory process to analyse and reflect on local networks and multi-stakeholder arenas. The two contrasting processes are analysed and their contribution to reflexive capacity building is assessed. Building on the findings, further advancements of MLP, COU, and the concept of reflexive governance are recommended. © 2013 Taylor & Francis.

Fromhage L.,University of Hamburg
Evolution | Year: 2012

Mating plugs are male-derived structures that may impede female remating by physically obstructing the female genital tract. Although mating plugs exist in many taxa, the forces shaping their evolution are poorly understood. A male can clearly benefit if his mating plug secures his paternity. It is unclear, however, how plug efficacy can be maintained over evolutionary time in the face of counteracting selection on males' ability to remove any plugs placed by their rivals. Here, I present a game-theory model and a simulation model to address this problem. The models predict that evolutionarily stable levels of mating-plug efficacy should be high when (1) the number of mating attempts per female is low; (2) the sex ratio is male-biased, and (3) males are sperm-limited. I discuss these results in the light of empirical data. © 2011 The Author(s). Evolution © 2011 The Society for the Study of Evolution.

Talke K.,University of Hamburg | Hultink E.J.,Technical University of Delft
Journal of Product Innovation Management | Year: 2010

In the last decade, there has been an increasing interest in the link between new product launch strategy and market performance. So far, new product launch research has focused on this performance relationship without giving much attention to background factors that can facilitate or inhibit successful launch strategies. However, investigating such antecedents that set the framework in which different strategic launch decisions enable or prevent the market performance of new products is useful for enhancing the current state of knowledge. Drawing on the concept of a firm's orientation, the present study discusses the influence of the corporate mind-set on new product launch strategy and market performance. It is hypothesized that the capability to successfully launch new products is based on the interplay between a firm's mind-set (i.e., an analytical, risk-taking, and aggressive posture) and its strategic launch decisions on setting launch objectives, selecting target markets, and positioning the new product. A research model with mediating effects is proposed, where the corporate mind-set determines the launch strategy decisions, which in turn impact market performance. The model is tested with data on 113 industrial new products launched in business-to-business markets in Germany using a multiple informant approach. The results support the mediated model as the dimensions of the corporate mind-set have a significant impact on most strategic launch decisions, which in turn significantly contribute to market performance. It is found that while an analytical posture relates to all three strategic launch decisions, risk taking and an aggressive posture have a significant impact on two, respectively one, launch strategy elements. These findings confirm the importance of investigating antecedents for a successful new product launch, as the corporate mind-set serves as a background resource that sets the framework for successful new product launch decisions. In the final section implications for research and managerial practice as well as limitations of this research are provided. © 2010 Product Development & Management Association.

Son S.-K.,German Electron Synchrotron | Young L.,Argonne National Laboratory | Santra R.,German Electron Synchrotron | Santra R.,University of Hamburg
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2011

X-ray free-electron lasers (FELs) are promising tools for structural determination of macromolecules via coherent x-ray scattering. During ultrashort and ultraintense x-ray pulses with an atomic-scale wavelength, samples are subject to radiation damage and possibly become highly ionized, which may influence the quality of x-ray scattering patterns. We develop a toolkit to treat detailed ionization, relaxation, and scattering dynamics for an atom within a consistent theoretical framework. The coherent x-ray scattering problem including radiation damage is investigated as a function of x-ray FEL parameters such as pulse length, fluence, and photon energy. We find that the x-ray scattering intensity saturates at a fluence of ∼107 photon/Å2 per pulse but can be maximized by using a pulse duration much shorter than the time scales involved in the relaxation of the inner-shell vacancy states created. Under these conditions, both inner-shell electrons in a carbon atom are removed, and the resulting hollow atom gives rise to a scattering pattern with little loss of quality for a spatial resolution >1 Å. Our numerical results predict that in order to scatter from a carbon atom 0.1 photon per x-ray pulse, within a spatial resolution of 1.7 Å, a fluence of 1×107 photons/Å2 per pulse is required at a pulse length of 1 fs and a photon energy of 12 keV. By using a pulse length of a few hundred attoseconds, one can suppress even secondary ionization processes in extended systems. The present results suggest that high-brightness attosecond x-ray FELs would be ideal for single-shot imaging of individual macromolecules. © 2011 American Physical Society.

Kroger N.,University of Hamburg
Current Opinion in Oncology | Year: 2011

Purpose of review: Relapse has become the leading cause of death following allogeneic hematopoietic stem cell transplantation (HSCT). Despite improved understanding of the biology that underlies the graft-versus-leukemia/tumor effect the relapse rate did not decrease over the past 20 years. In general, prognosis is poor for patients who relapsed to an allograft since effective treatment options are limited. Here, we review the available and upcoming treatment approaches for relapse. Recent findings: Treatment of relapse after allogeneic HSCT has been rarely investigated systematically and results differ substantially from diseases. Withdrawal of immunosuppressive medication, donor lymphocyte infusions with or without chemotherapy and/or second allogeneic HSCT are the most used options. New specific cellular approaches such as disease-specific T-cells, alloreactive natural killer cells or vaccination strategies are under investigation. Novel agents such as tyrosine-kinase inhibitors, hypomethylating agents, monoclonal antibodies, immunomodulating drugs, or proteasome-inhibitors either alone or in combination with adoptive immunotherapy are upcoming promising options, but valid data are lacking so far. Summary: With some exceptions (chronic myeloid leukemia), treatment options for patients who relapse are limited. The results are poor and the majority of patients ultimately die of their disease. More effort and research is needed to prevent and treat relapse after allogeneic HSCT. © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Talke K.,University of Hamburg | Hultink E.J.,Technical University of Delft
Journal of Product Innovation Management | Year: 2010

In recent years there has been a growing interest in the link between new product launch activities and market success. So far, most empirical research has focused on launch activities that target customer adoption barriers. However, with such a focus the influence of other stakeholders on innovation diffusion is not taken into account. A review of diffusion research and stakeholder theory serves as a basis for discussing the influence of different stakeholder groups such as customers, dealers, suppliers, and competitors on innovation diffusion. Essentially, it is expected that addressing multiple diffusion barriers during new product launch will have a positive impact on market success. The new concept for launch activities addressing multiple diffusion barriers is tested with data on new product launches in industrial markets using a multiple-informant approach. The results lend support to the notion that a successful launch requires activities addressing diffusion barriers related to different stakeholder groups. Specifically, barriers related to customers, suppliers, and stakeholders of the further firm environment need to be lowered during market launch. For the group of competitors, a balanced launch approach including measures to both lowering and erecting entry and diffusion barriers will increase the market success of new products. The subsequent investigation of the influence of technological turbulence, market turbulence, and product complexity on the performance relationships shows that under high uncertainty managing multiple-diffusion barriers is of higher relevance than in more unambiguous, clear-cut contexts. Thus, the results demonstrate that a careful management of diffusion barriers related to multiple stakeholders is a relevant task when launching a new product. The paper concludes with implications for management practice and avenues for future academic research. © 2010 Product Development and Management Association.

Kolorenc J.,ASCR Institute of Physics Prague | Kolorenc J.,University of Hamburg | Mitas L.,North Carolina State University
Reports on Progress in Physics | Year: 2011

Quantum Monte Carlo methods represent a powerful and broadly applicable computational tool for finding very accurate solutions of the stationary Schrödinger equation for atoms, molecules, solids and a variety of model systems. The algorithms are intrinsically parallel and are able to take full advantage of present-day high-performance computing systems. This review paper concentrates on the fixed-node/fixed-phase diffusion Monte Carlo method with emphasis on its applications to the electronic structure of solids and other extended many-particle systems. © 2011 IOP Publishing Ltd.

Schroeder C.B.,Lawrence Berkeley National Laboratory | Benedetti C.,Lawrence Berkeley National Laboratory | Esarey E.,Lawrence Berkeley National Laboratory | Gruner F.J.,University of Hamburg | Leemans W.P.,Lawrence Berkeley National Laboratory
Physical Review Letters | Year: 2011

A long, relativistic particle beam propagating in an overdense plasma is subject to the self-modulation instability. This instability is analyzed and the growth rate is calculated, including the phase relation. The phase velocity of the wake is shown to be significantly less than the beam velocity. These results indicate that the energy gain of a plasma accelerator driven by a self-modulated beam will be severely limited by dephasing. In the long-beam, strongly coupled regime, dephasing is reached in a homogeneous plasma in less than four e foldings, independent of beam-plasma parameters. © 2011 American Physical Society.

Zurbig P.,Mosaiques Diagnostics GmbH | Jahn H.,University of Hamburg
Electrophoresis | Year: 2012

Proteomics is the study of the entire population of proteins and peptides in an organism or a part of it, such as a cell, tissue, or fluids like cerebrospinal fluid, plasma, serum, urine, or saliva. It is widely assumed that changes in the composition of the proteome may reflect disease states and provide clues to its origin, eventually leading to targets for new treatments. The ability to perform large-scale proteomic studies now is based jointly on recent advances in our analytical methods. Separation techniques like CE and 2DE have developed and matured. Detection methods like MS have also improved greatly in the last 5 years. These developments have also driven the fields of bioinformatics, needed to deal with the increased data production and systems biology. All these developing methods offer specific advantages but also come with certain limitations. This review describes the different proteomic methods used in the field, their limitations, and their possible pitfalls. Based on a literature search in PubMed, we identified 112 studies that applied proteomic techniques to identify biomarkers for Alzheimer disease. This review describes the results of these studies on proteome changes in human body fluids of Alzheimer patients reviewing the most important studies. We extracted a list of 366 proteins and peptides that were identified by these studies as potential targets in Alzheimer research. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Runkel I.,University of Hamburg
Journal of Physics A: Mathematical and Theoretical | Year: 2010

Perturbing a Virasoro minimal model by the (1,3) primary bulk field results in an integrable field theory. In this paper, an infinite set of commuting conserved charges is obtained by considering defects: a one-parameter family of perturbed defect operators is given, and it is shown that these operators mutually commute, they commute with the Hamiltonian of the perturbed conformal field theories and they satisfy a T-system functional relation. The formulation in terms of perturbed defects is a modification of the original prescription for such charges by Bazhanov, Lukyanov and Zamolodchikov. © 2010 IOP Publishing Ltd.

Yagi J.,University of Hamburg
Journal of High Energy Physics | Year: 2012

The six-dimensional (2, 0) theory formulated in the Ω-background gives rise to two-dimensional effective degrees of freedom. By compactifying the theory on the circle fibers of two cigar-like manifolds, we find that a natural candidate for the effective theory is a chiral gauged WZW model. The symmetry algebra of the model contains the W-algebra that appears on the two-dimensional side of the AGT correspondence. We show that the expectation values of its currents determine the Seiberg-Witten curve of the four-dimensional side. © SISSA 2012.

Johnsen S.A.,University of Hamburg | Johnsen S.A.,University of Gottingen
FEBS Letters | Year: 2012

The post-translational modification of histone proteins plays an important role in controlling cell fate by directing essentially all DNA-associated nuclear processes. Misregulation and mutation of histone modifying enzymes is a hallmark of tumorigenesis. However, how these different epigenetic modifications lead to tumor initiation and/or progression remains poorly understood. Recent studies have uncovered a potential tumor suppressor role for histone H2B monoubiquitination (H2Bub1). Like many other histone modifications, H2Bub1 has diverse functions and plays roles both in transcriptional activation and repression as well as in controlling mRNA processing and directing DNA repair processes. Notably, H2Bub1 has been linked to transcriptional elongation and is preferentially found in the transcribed region of active genes. Its activity is intimately connected to active transcription and the transcriptional elongation regulatory protein cyclin-dependent kinase-9 (CDK9) and the facilitates chromatin transcription (FACT) complex. This review provides an overview of the current understanding of H2Bub1 function in mammalian systems with a particular emphasis on its role in cancer and potential options for exploiting this knowledge for the treatment of cancer. © 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Guse A.H.,University of Hamburg
Science Signaling | Year: 2012

Nicotinic acid adenine dinucleotide phosphate (NAADP) is a potent Ca 2+-releasing second messenger that might regulate different ion channels, including the ryanodine receptor, two-pore channels, and TRP-ML1 (transient receptor potential channel, subtype mucolipin 1), a Ca2+ channel localized to lysosomes. New evidence suggests that a 22- and 23-kilodalton pair of proteins could be the receptor for NAADP. Labeling of NAADP binding proteins was independent of overexpression or knockout of two-pore channels, indicating that two-pore channels, although regulated by NAADP, are not the NAADP receptors. I propose that NAADP binding proteins could bind to different ion channels and thus may explain how NAADP regulates diverse ion channels.

Schnabel R.B.,University of Hamburg
Clinical Cardiology | Year: 2012

Atrial fibrillation (AF) is a complex disease with increasing prevalence in an aging population and longer survival with cardiovascular diseases. Whereas most clinical efforts have been aimed at predicting risk of AF sequelae such as stroke and heart failure, little is known on primary prevention. AF risk assessment is complicated by the existence of distinct subtypes of AF, such as lone AF or postoperative AF, in contrast to common AF in the elderly. Due to its often intermittent nature, diagnosing AF can be a challenge. Risk prediction becomes reasonable when specific interventions arise. Due to our limited understanding of AF pathophysiology and substantial lack of specific preventive strategies in the population, modification of the general cardiovascular risk profile has largely remained the only option. Initial attempts at combining established risk factors for AF such as age, sex, hypertension, body mass index, electrocardiographic characteristics, and cardiovascular disease in a risk-prediction instrument have produced a robust algorithm. However, known risk factors only explain a fraction of the population-attributable risk of AF, and the search for novel risk indicators is ongoing. More efficient monitoring for electrocardiographic precursors of AF and the field of genomics are evolving areas of AF risk factor research. A better understanding of the underlying substrate of AF will provide targets for prevention. In the future, clinical trials will be needed to establish risk categories, interventions, and their efficacy. Despite a relevant public-health impact, knowledge on risk prediction and primary prevention of AF is still limited today. © 2012 Wiley Periodicals, Inc.

Stammer D.,University of Hamburg | Cazenave A.,CNRS Geophysical Research and Oceanographic Laboratory | Ponte R.M.,Atmospheric and Environmental Research Inc. | Tamisiea M.E.,National Oceanographic Center
Annual Review of Marine Science | Year: 2013

Regional sea level changes can deviate substantially from those of the global mean, can vary on a broad range of timescales, and in some regions can even lead to a reversal of long-term global mean sea level trends. The underlying causes are associated with dynamic variations in the ocean circulation as part of climate modes of variability and with an isostatic adjustment of Earth's crust to past and ongoing changes in polar ice masses and continental water storage. Relative to the coastline, sea level is also affected by processes such as earthquakes and anthropogenically induced subsidence. Present-day regional sea level changes appear to be caused primarily by natural climate variability. However, the imprint of anthropogenic effects on regional sea level-whether due to changes in the atmospheric forcing or to mass variations in the system-will grow with time as climate change progresses, and toward the end of the twenty-first century, regional sea level patterns will be a superposition of climate variability modes and natural and anthropogenically induced static sea level patterns. Attribution and predictions of ongoing and future sea level changes require an expanded and sustained climate observing system. © 2013 by Annual Reviews. All rights reserved.

Ferulate dehydrodimers and the more recently discovered dehydrotrimers play an important role in the cell wall architecture of plant-based foods and forages. High-performance liquid chromatography methods to determine ferulate dimers often lack specificity; methods for trimers did not exist yet. A method for the determination of 11 cell wall-bound ferulate dehydrodimers and -trimers was developed, including the crucial separation of the di/trimers from the often dominating phenolic monomers. Validation parameters for the basic calibration of the dimers and trimers met our acceptance criteria. However, the matrix calibration revealed that lignin-rich matrices lead to problems with precision and accuracy that likely can be addressed by using a more specific detection, that is, mass spectrometric detection, next to improved sample preparation procedures. The method was used to analyze low-lignin fibers from corn, wheat, and rye grains, wild rice, asparagus, and sugar beet. With the exception of wild rice, the 5-5/8-O-4-, 8-O-4/8-O-4-, and 8-8(aryltetralin)/8-O-4-dehydrotrimers were detected in all analyzed samples, however, often in amounts below the limit of quantitation. © 2010 American Chemical Society.

Tremblay S.,McGill University | Tremblay S.,Montreal Neurological Institute | Pieper F.,University of Hamburg | Sachs A.,Ottawa Hospital Research Institute | And 2 more authors.
Neuron | Year: 2015

The activity of neurons in the primate lateral prefrontal cortex (LPFC) is strongly modulated by visual attention. Such a modulation has mostly been documented by averaging the activity of independently recorded neurons over repeated experimental trials. However, in realistic settings, ensembles of simultaneously active LPFC neurons must generate attentional signals on a single-trial basis, despite the individual and correlated variability of neuronal responses. Whether, under these circumstances, the LPFC can reliably generate attentional signals is unclear. Here, we show that the simultaneous activity of neuronal ensembles in the primate LPFC can be reliably decoded to predict the allocation of attention on a single-trial basis. Decoding was sensitive to the noise correlation structure of the ensembles. Additionally, it was resilient to distractors, predictive ofbehavior, and stable over weeks. Thus, LPFC neuronal ensemble activity can reliably encode attention within behavioral timeframes, despite the noisy and correlated nature of neuronal activity. © 2015 Elsevier Inc.

Cnossen I.,British Antarctic Survey | Franzke C.,University of Hamburg
Journal of Geophysical Research A: Space Physics | Year: 2014

We applied Ensemble Empirical Mode Decomposition (EEMD) for the first time to ionosonde data to study trends in the critical frequency of the F2 peak, foF2, and its height, hmF2, from 1959 to 2005. EEMD decomposes a time series into several quasi-cyclical components, called Intrinsic Mode Functions, and a residual, which can be interpreted as a long-term trend. In contrast to the more commonly used linear regression-based trend analysis, EEMD makes no assumptions on the functional form of the trend and no separate correction for the influence of solar activity variations is needed. We also adopted a more rigorous significance testing procedure with less restrictive underlying assumptions than the F test, which is normally used as part of a linear regression-based trend analysis. EEMD analysis shows that trends in hmF2 and foF2 between 1959 and 2005 are mostly highly linear, but the F test tends to overestimate the significance of trends in hmF2 and foF2 in 30% and 25% of cases, respectively. EEMD-based trends are consistently more negative than linear regression-based trends, by 30-35% for hmF2 and about 50% for foF2. This may be due to the different treatment of the influence of a long-term decrease in solar activity from 1959 to 2005. We estimate the effect of this decrease in solar activity with two different data-based methods as well as using numerical model simulations. While these estimates vary, all three methods demonstrate a larger relative influence of the Sun on trends in foF2 than on trends in hmF2. © 2014. American Geophysical Union. All Rights Reserved.

David N.,University of Hamburg | Fiori F.,University of Rome La Sapienza | Aglioti S.M.,University of Rome La Sapienza
Cognitive, Affective and Behavioral Neuroscience | Year: 2014

The rubber hand illusion (RHI) is an enigmatic illusion that creates a feeling of owning an artificial limb. Enthusiasts of this paradigm assert that it operationalizes bodily self-awareness, but there are reasons to doubt such a clear link. Because little is known about other functional contributions to the RHI, including effects of context-dependent visual processing and cognitive control or the ability to resolve intermodal conflict, we carried out two complementary experiments. In the first, we examined the relationships between the RHI and (1) body awareness, as assessed by the Body Perception Questionnaire (BPQ); (2) context-dependent visual processing, as assessed by the rod-and-frame test (RFT); and (3) conflict resolution, as assessed by the Stroop test. We found a significant positive correlation between the RHI-associated proprioceptive drift and context-dependent visual processing on the RFT, but not between the RHI and body awareness on the BPQ. In the second experiment, we examined the RHI in advanced yoga practitioners with an embodied lifestyle and a heightened sense of their own body in space. They succumbed to the illusion just as much as did yoga-naïve control participants, despite significantly greater body awareness on the BPQ. These findings suggest that susceptibility to the RHI and awareness of one's own body are at least partially independent processes. © 2013 Psychonomic Society, Inc.

Evoli C.,University of Hamburg | Yan H.,Peking University
Astrophysical Journal | Year: 2014

We revisit propagation of galactic cosmic rays (CRs) in light of recent advances in CR diffusion theory in realistic interstellar turbulence. We use a tested model of turbulence in which it has been shown that fast modes dominate scattering of CRs. As a result, propagation becomes inhomogeneous and environment dependent. By adopting the formalism of the nonlinear theory developed by Yan & Lazarian, we calculate the diffusion of CRs self-consistently from first principles. We assume a two-phase model for the Galaxy to account for different damping mechanisms of the fast modes, and we find that the energy dependence of the diffusion coefficient is mainly affected by medium properties. We show that it gives a correct framework to interpret some of the recent CR puzzles. © 2014. The American Astronomical Society. All rights reserved..

Fiori F.,University Rome | David N.,University of Hamburg | Aglioti S.M.,University Rome
Frontiers in Human Neuroscience | Year: 2014

In the rod and frame test (RFT), participants are asked to set a tilted visual linear marker (i.e., a rod), embedded in a square, to the subjective vertical, irrespective of the surrounding frame. People not influenced by the frame tilt are defined as field-independent, while people biased in their rod verticality perception are field-dependent. Performing RFT requires the integration of proprioceptive, vestibular and visual signals with the latter accounting for field-dependency. Studies indicate that motor experts in body-related, balance-improving disciplines tend to be field-independent, i.e., better at verticality perception, suggesting that proprioceptive and vestibular expertise acquired by such exercise may weaken the influence of irrelevant visual signals. What remains unknown is whether the effect of body-related expertise in weighting perceptual information might also be mediated by personality traits, in particular those indexing self-focusing abilities. To explore this issue, we tested field-dependency in a class of body experts, namely yoga practitioners and in non-expert participants. Moreover we explored any link between performance on RFT and self-transcendence (ST), a complex personality construct, which refers to tendency to experience spiritual feelings and ideas. As expected, yoga practitioners (i) were more accurate in assessing the rod’s verticality on the RFT, and (ii) expressed significantly higher ST. Interestingly, the performance in these two tests was negatively correlated. More specifically, when asked to provide verticality judgments, highly self-transcendent yoga practitioners were significantly less influenced by a misleading visual context. Our results suggest that being highly self-transcendent may enable yoga practitioners to optimize verticality judgment tasks by relying more on internal (vestibular and proprioceptive) signals coming from their own body, rather than on exteroceptive, visual cues. © 2014 Fiori, David and Aglioti.

Androutsopoulos J.,University of Hamburg
Journal of Pragmatics | Year: 2014

This paper reports findings of a case study of the networked language practices of two young users of the social networking site Facebook. Theoretically informed by sociolinguistics and computer-mediated discourse analysis, this paper contributes to the study of language and participation in social media by developing an empirical approach to sharing and by focusing on the relation between sharing practices and linguistic repertoires. The paper proposes an understanding of sharing as an interactional practice of entextualizing significant moments for a networked audience. Data collection and analysis follow a mixed-methods approach. The primary data consists of the participants' public Facebook timelines during a period of one year. It is complemented by qualitative interviews and systematic observation of the their digital literacy practices on Facebook. The analysis distinguishes three stages of sharing - selecting, styling, and negotiating - and then moves on to individual case studies, which illustrate how the two participants mobilise linguistic resources in order to share moments of transnational mobility with their audience. The findings show how subtle shifts in the selection, combination and negotiation of linguistic resources index participants' transnational trajectories and their orientation to particular subsets of their audience, and how the audience takes an active role in negotiating the modes and meanings of sharing in social networking. © 2014 Elsevier B.V..

Malcherek T.,University of Hamburg
Journal of Applied Crystallography | Year: 2011

The order-disorder contributions to the ferroelectric properties of Cd 2Nb2O7 (CNO) have been studied by Monte Carlo simulation of a 12-state modified Potts model on the pyrochlore lattice. Spin configurations obtained by these simulations are mapped to local Nb displacements. Secondary Cd displacements normal to the Nb displacement directions are considered as well. The model correctly reproduces diffuse scattering experimentally observed in CNO. A first-order phase transition is observed for kT p/J = 0.3891 (k is the Boltzmann constant, T p is the model phase transition temperature and J is the interaction energy). To further adapt the model to the properties of CNO, coupling of local Nb displacements to the T 2u soft mode is simulated via the addition of an appropriate field term in the model Hamiltonian. The critical temperature T c of the soft mode is scaled to kT c/J= 0.3704. Similarities to experimental observations, i.e. the occurrence of stable domains with {100} boundaries, as well as spontaneous polarization along the cubic 100 and 110 directions, indicate that T p can be associated with the transition temperature T 1 = 205 K in CNO. Frequency dispersion of the dielectric permittivity of CNO can be attributed to the low-frequency switching of correlated chains of Nb displacement that remain partially disordered in the temperature range between 195 and 100 K. © 2011 International Union of Crystallography Printed in Singapore - all rights reserved.

Peano V.,Albert Ludwigs University of Freiburg | Thorwart M.,University of Hamburg
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

We analyze the driven resonantly coupled Jaynes-Cummings model in terms of a quasienergy approach by switching to a frame rotating with the external modulation frequency and by using the dressed atom picture. A quasienergy surface in phase space emerges whose level spacing is governed by a rescaled effective Planck constant. Moreover, the well-known multiphoton transitions can be reinterpreted as resonant tunneling transitions from the local maximum of the quasienergy surface. Most importantly, the driving defines a quasienergy well which is nonperturbative in nature. The quantum-mechanical quasienergy state localized at its bottom is squeezed. In the Purcell-limited regime, the potential well is metastable and the effective local temperature close to its minimum is uniquely determined by the squeezing factor. The activation occurs in this case via dressed spin-flip transitions rather than via quantum activation as in other driven nonlinear quantum systems such as the quantum Duffing oscillator. The local maximum is, in general, stable. However, in presence of resonant coherent or dissipative tunneling transitions the system can escape from it and a stationary state arises as a statistical mixture of quasienergy states being localized in the two basins of attraction. This gives rise to a resonant or an antiresonant nonlinear response of the cavity at multiphoton transitions. The model finds direct application in recent experiments with a driven superconducting circuit quantum electrodynamics setup. © 2010 The American Physical Society.

Given the diffusion of the Social Web and increased disclosure of personal information online, the 'privacy paradox' suggests that while Internet users are concerned about privacy, their behaviors do not mirror those concerns. This study investigates the potential influence of privacy concerns, psychological traits, attitudes to the Social Web and age on self-disclosure. Using an online survey of a representative sample of German Internet users (n=2, 739), the variety and quality of self-disclosure as well as access were measured. The findings indicate that privacy concerns hardly impact self-disclosure, but different variables moderate this relation. Perceived social relevance and the number of applications used proved important. Users' general willingness to disclose is most important when providing sensitive information. © 2013 International Communication Association.

Li H.,University of Turku | Liu Y.,University of Hamburg
Information and Management | Year: 2014

We developed a model to investigate the factors influencing two different post-adoption behaviors of e-service users based on the Post-Acceptance Model of IS Continuance (IS continuance model): (1) continuance intention to use e-services; and (2) Word of Mouth (WOM) behavior. We tested the research model using a survey of 543 usable responses in China. Our findings show that satisfaction and perceived usefulness positively affect continuance intention, which, together with perceived usefulness, positively influences the WOM behavior. The two different post-adoption behaviors of e-service users, continuance intention and WOM, are closely related. Implications for theory and practice are also discussed. © 2014 Elsevier B.V. All rights reserved.

Fallahi A.,University of Hamburg | Perruisseau-Carrier J.,Ecole Polytechnique Federale de Lausanne
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

Periodic structures with subwavelength features are instrumental in the versatile and effective control of electromagnetic waves from radio frequencies up to optics. In this paper, we theoretically evaluate the potential applications and performance of electromagnetic metasurfaces made of periodically patterned graphene. Several graphene metasurfaces are presented, thereby demonstrating that such ultrathin surfaces can be used to dynamically control the electromagnetic wave reflection, absorption, or polarization. Indeed, owing to the graphene properties, the structure performance in terms of resonance frequencies and bandwidths changes with the variation of electrostatic bias fields. To demonstrate the applicability of the concept at different frequency ranges, the examples provided range from microwave to infrared, corresponding to graphene features with length scales of a few millimeters down to about a micrometer, respectively. The results are obtained using a full-vector semianalytical numerical technique developed to accurately model the graphene-based multilayer periodic structures under study. © 2012 American Physical Society.

Etkin A.,Stanford University | Etkin A.,Education and Clinical Center | Buchel C.,University of Hamburg | Gross J.J.,Stanford University
Nature Reviews Neuroscience | Year: 2015

Emotions are powerful determinants of behaviour, thought and experience, and they may be regulated in various ways. Neuroimaging studies have implicated several brain regions in emotion regulation, including the ventral anterior cingulate and ventromedial prefrontal cortices, as well as the lateral prefrontal and parietal cortices. Drawing on computational approaches to value-based decision-making and reinforcement learning, we propose a unifying conceptual framework for understanding the neural bases of diverse forms of emotion regulation. © 2015 Macmillan Publishers Limited.

Berger T.,University of Hamburg
Mathematics of Control, Signals, and Systems | Year: 2014

We study exponential stability and its robustness for time-varying linear index-1 differential-algebraic equations. The effect of perturbations on the leading coefficient matrix is investigated. An appropriate class of allowable perturbations is introduced. Robustness of exponential stability with respect to a certain class of perturbations is proved in terms of the Bohl exponent and perturbation operator. Finally, a stability radius involving these perturbations is introduced and investigated. In particular, a lower bound for the stability radius is derived. The results are presented by means of illustrative examples. © 2013 Springer-Verlag London.

Eden C.,University of Hamburg
Ocean Modelling | Year: 2011

Linear instability theory is used to predict the lateral diffusivity K for eddy buoyancy fluxes in an idealized channel model, following a suggestion by Killworth (1997). The vertical structure and magnitude of K agree approximately with the non-linear model results. The lateral structure of K from linear theory lacks minima within eddy-driven zonal jets, pointing towards a non-linear mechanism for mixing barriers in the channel model. This effect can be accounted for by a modification of K from linear theory by the kinematic effect of the background flow following a recent suggestion by Ferrari and Nikurashin (2010). Implementation of this closure for K in an eddy mixing framework based on potential vorticity mixing in a zonally averaged model version yields approximate agreement with the zonally resolved version over a certain range of external parameters, in particular with respect to the reproduction of eddy-driven zonal jets. © 2011 Elsevier Ltd.

Luthen H.,University of Hamburg
Journal of Plant Growth Regulation | Year: 2015

Auxin is the plant hormone with the longest history, harking back to the days of Charles Darwin. Modern research focuses on auxin signal transduction and auxin transport, and it has become more and more evident that auxin gradients shape the plant. Many of today’s successful concepts have early roots, which are easily forgotten. This review tries to highlight some of them, without striving for any completeness. © 2015, Springer Science+Business Media New York.

Stribeck N.,University of Hamburg
Polymer Reviews | Year: 2010

Synchrotron facilities with improved equipment will grant the execution of very advanced scattering experiments to every interested polymer scientist. The patterns recorded are two-dimensional, high-resolution, and low-noise images. They permit to monitor structure evolution during the processing of polymer materials with repeat rates of several Hertz. In a different class of novel experiments the structure gradient inside of graded polymer materials will be determined with a spatial resolution of less than 1 m. Scattering patterns must be complete. In order both to record complete patterns, and to evaluate them within tolerable time it appears reasonable to study parts with fiber symmetry. In the present paper a review of corresponding methodical work and the results of test experiments is presented that has recently been compiled in the group of the author.

Pisoiu D.,University of Hamburg
Terrorism and Political Violence | Year: 2015

This article assesses the applicability of subcultural theories to individual cases ofjihadi and Right-wing radicalization in Germany, with a focus on the individual initial situation and motivation for involvement. Within an overall qualitative research design, the article tests deviance/strain and Centre for Contemporary Cultural Studies (CCCS) subcultural theories against four jihadi and three Right-wing extremist cases. The findings show little support for the strain-based status frustration hypothesis, but confirm the illegitimate opportunity structure thesis; modified versions of the CCCS’ resistance, bricolage, and homology concepts; as well as some of the postmodern approaches to agency and cultural cross-fertilization. The jihadi and Right-wing radicals examined here are assertive and purposive agents, strategically using the rich cultural arsenal available in the mainstream and/or other subcultures, while at the same time being themselves influenced by contemporary mainstream preferences of style. The article discusses the implications of these findings for radicalization research and specific subcultural approaches. It argues for a greater focus on both individual agency and the (sub-)cultural context for an improved understanding of individual involvement in political violence. © Taylor & Francis Group, LLC.

Hancock P.E.,University of Surrey | Pascheke F.,University of Hamburg
Boundary-Layer Meteorology | Year: 2014

Measurements have been made in the wake of a model wind turbine in both a neutral and a stable atmospheric boundary layer, in the EnFlo stratified-flow wind tunnel, between 0.5 and 10 rotor diameters from the turbine, as part of an investigation of wakes in offshore winds. In the stable case the velocity deficit decreased more slowly than in the neutral case, partly because the boundary-layer turbulence levels are lower and the consequentially reduced level of mixing, an 'indirect' effect of stratification. A correlation for velocity deficit showed the effect of stratification to be the same over the whole of the measured extent, following a polynomial form from about five diameters. After about this distance (for the present stratification) the vertical growth of the wake became almost completely suppressed, though with an increased lateral growth; the wake in effect became 'squashed', with peaks of quantities occurring at a lower height, a 'direct' effect of stratification. Generally, the Reynolds stresses were lower in magnitude, though the effect of stratification was larger in the streamwise fluctuation than on the vertical fluctuations. The vertical heat flux did not change much from the undisturbed level in the first part of the wake, but became much larger in the later part, from about five diameters onwards, and exceeded the surface level at a point above hub height. © 2013 Springer Science+Business Media Dordrecht.

Moritz S.,University of Hamburg | Van Quaquebeke N.,University of Management and Economics
Cognitive Neuropsychiatry | Year: 2014

Introduction Paranoid beliefs strongly impact behaviour and emotion: Most people with paranoid delusions engage in safety behaviours and a relevant minority even commits violent acts under the influence of delusional thoughts. The present study examined whether different levels of belief conviction modulate subsequent behaviour and emotion. To be able to control for important confounds, we set up an analogue study using nonclinical participants. Methods Participants were recruited from the general population (N=1935) and asked to fill out the Paranoia Checklist. Individuals had to imagine being persecuted by a secret service, whereby the level of subjective conviction was set at 20%, 40%, 60%, 80%, 90%, or 100%. Subsequently, participants had to estimate for 37 behavioural and emotional items how they might respond to this threat. Results Three quarters of the sample affirmed the presence of at least one paranoid idea from the Paranoia Checklist over the duration of a month. The level of belief conviction and paranoia was positively associated with behavioural and emotional consequences. Conclusions Our investigation suggests that a higher degree of belief conviction aggravates the behavioural consequences of persecutory beliefs in a linear fashion. The study is limited by its "what if" character and should be replicated with clinical participants. The study suggests that treatment approaches that aim to reduce overconviction may positively impact behaviour in psychosis. © 2013 Taylor & Francis.

Kricheldorf H.R.,University of Hamburg | Weidner S.M.,BAM Federal Institute of Materials Research and Testing
European Polymer Journal | Year: 2013

Using SnCl2, ZnCl2, Zn-lactate or Zr-acetylacetonate as catalysts l-lactide was oligomerized in bulk with isosorbide as initiator. The ratio isosorbide/lactide was varied from 8/2 to 2/8. The resulting oligomers were in situ polycondensed with isophthaloyl chloride in various aromatic solvents. In chlorobenzene homogeneous reaction mixtures were obtained, whereas molten copolyesters precipitated from toluene and xylene. The obtained average molecular weights indicated high polydispersities. According to MALDI-TOF MS the low molar mass reaction products (<4 kDa) almost exclusively consisted of cyclics with a composition depending on the feed ratio. The glass-transition temperatures (Tg) varied between the values of poly(l-lactide (64 C) and poly(isosorbide isophthalate) (180 C). Four polyesters prepared from 5-tert-butyl isophthalic acid displayed higher Tg values. Differential thermoanalysis evidenced that the thermostability decreases with higher fractions of lactide, but processing from the melt seems to be feasible up to temperatures of 260 C without risking degradation.

Zhu X.,University of Hamburg | Wang W.,CAS South China Sea Institute of Oceanology | Fraedrich K.,Max Planck Institute for Meteorology
Journal of Climate | Year: 2013

The authors use a statistical regional climate model [Statistical Regional Model (STAR)] to project the Tibetan Plateau (TP) climate for the period 2015-50. Reanalysis datasets covering 1958-2001 are used as a substitute of observations and resampled by STAR to optimally fit prescribed linear temperature trends derived from the Max Planck Institute Earth System Model (MPI-ESM) simulations for phase 5 of the Coupled Model Intercomparison Project (CMIP5) under the representative concentration pathway 2.6 (RCP2.6) and RCP4.5 scenarios. To assess the related uncertainty, temperature trends from carefully selected best/worst ensemble members are considered. In addition, an extra projection is forced by observed temperature trends in 1958-2001. The following results are obtained: (i) Spatial average temperature will increase by 0.6°-0.9°C; the increase exceeds 18C in all months except in boreal summer, thus indicating a reduced annual cycle; and daily minimum temperature rises faster than daily maximum temperature, resulting in a narrowing of the diurnal range of near-surface temperature. (ii) Precipitation increase mainly occurs in early summer and autumn possibly because of an earlier onset and later withdrawal of the Asian summer monsoon. (iii) Both frost and ice days decrease by 1-2 days in spring, early summer, and autumn, and the decrease of frost days on the annual course is inversely related to the precipitation increase. (iv) Degree-days increase all over the TP with peak amplitude in the Qaidam Basin and the southern TP periphery, which will result in distinct melting of the local seasonal frozen ground, and the annual temperature range will decrease with stronger amplitude in south TP. © 2013 American Meteorological Society.

Seimetz D.,Fresenius Biotech GmbH | Lindhofer H.,TRION Pharma GmbH | Bokemeyer C.,University of Hamburg
Cancer Treatment Reviews | Year: 2010

Catumaxomab is a trifunctional antibody (trAb) characterized by its unique ability to bind three different cell types: tumor cells, T-cells, and accessory cells. It has two different antigen-binding specificities: one for epithelial cell adhesion molecule (EpCAM) on tumor cells and one for the CD3 antigen on T-cells. Catumaxomab also binds to type I, IIa, and III Fcγ receptors (FcγR) on accessory cells, e.g. macrophages, dendritic cells, and natural killer cells, via its intact Fc region. Its anti-tumor activity results from T-cell-mediated lysis, antibody-dependent cell-mediated cytotoxicity, and phagocytosis via activation of FcγR-positive accessory cells. Importantly, no additional activation of immune cells is necessary for effective tumor eradication by catumaxomab, which represents a self-supporting system. Catumaxomab's efficacy and safety have been demonstrated in a pivotal phase II/III study and supporting phase I/II studies. It is administered as four intraperitoneal (i.p.) infusions on days 0, 3, 7, and 10 at doses of 10, 20, 50, and 150μg, respectively. Catumaxomab has been approved in the European Union since April 2009 for the i.p. treatment of malignant ascites (MA) in patients with EpCAM-positive carcinomas where standard therapy is not available or no longer feasible. Catumaxomab is the first trAb and the first drug worldwide to be approved specifically for the treatment of MA. It is in clinical trials in a number of other indications including ovarian and gastric cancer. Alternative routes of administration are also under evaluation to further exploit the therapeutic potential of catumaxomab in EpCAM-positive carcinomas. © 2010 Elsevier Ltd.

Gabriel G.,Heinrich Pette Institute | Arck P.C.,University of Hamburg
Journal of Infectious Diseases | Year: 2014

Sex-specific endocrine and immune responses are widely recognized to account for differential disease outcomes between females and males. Surprisingly, sex-specific risk assessments for influenza, a viral pathogen that affects human populations worldwide through seasonal epidemics and irregular occurring pandemics, are sparse and - if available - ambiguous. To date, this precludes proposing an unequivocal sex-dependent susceptibility to influenza. However, one undisputable observation recurrently confirmed during influenza seasons of the last decades is the significantly increased risk for pregnant women. This increased risk is likely attributable to the contradictory demands for the maternal immune system to adapt to pregnancy and to simultaneously mount an immune response to clear the influenza virus infection. Here, we review published evidence on the potential association between sex on influenza risk and propose that future epidemiologic studies should carefully dissect surveillance data for sex-specific effects. Moreover, we propose potential mechanisms involved in enhanced risk for severe influenza during pregnancy that could be studied to identify causal pathways. © 2014 The Author.

Reidegeld F.,University of Hamburg
Differential Geometry and its Application | Year: 2010

We classify all seven-dimensional manifolds which admit a homogeneous cosymplectic G2-structure. The motivation for this classification is that each of these spaces is a possible principal orbit of a parallel Spin(7)-manifold of cohomogeneity one. © 2009 Elsevier B.V.

Lincoln T.M.,University of Hamburg | Mehl S.,University of Marburg | Kesting M.-L.,University of Marburg | Rief W.,University of Marburg
Schizophrenia Bulletin | Year: 2011

Background: How to improve treatment for negative symptoms is a continuing topic of debate. Suggestions have been made to advance psychological understanding of negative symptoms by focusing on the social cognitive processes involved in symptom formation and maintenance. Methods: Following the recommendations by the National Institute of Mental Health workshop on social cognition in schizophrenia, this study investigated associations between negative symptoms and various aspects of social cognition including Theory of Mind (ToM), attribution, empathy, self-esteem, and interpersonal self-concepts in 75 patients with schizophrenia spectrum disorders and 75 healthy controls. Results: Negative symptoms were significantly associated with difficulties in ToM, less readiness to be empathic, lower self-esteem, less self-serving bias, negative self-concepts related to interpersonal abilities, and dysfunctional acceptance beliefs. Different aspects of social cognition were mildly to moderately correlated and interacted in their impact on negative symptoms: Difficulties in ToM were associated with negative symptoms in persons with low but not in persons with medium or high levels of self-esteem. Taken together, the social cognition variables and their hypothesized interaction explained 39% of the variance in negative symptoms after controlling for neurocognition and depression. Conclusions: The results highlight the relevance of self-concepts related to social abilities, dysfunctional beliefs, and global self-worth alone and in interaction with ToM deficits for negative symptoms and thereby provide a helpful basis for advancing psychosocial interventions. © 2011 The Author.

Lucarini V.,University of Reading | Ragone F.,University of Hamburg
Reviews of Geophysics | Year: 2011

We analyze the publicly released outputs of the simulations performed by climate models (CMs) in preindustrial (PI) and Special Report on Emissions Scenarios A1B (SRESA1B) conditions. In the PI simulations, most CMs feature biases of the order of 1 W m-2 for the net global and the net atmospheric, oceanic, and land energy balances. This does not result from transient effects but depends on the imperfect closure of the energy cycle in the fluid components and on inconsistencies over land. Thus, the planetary emission temperature is underestimated, which may explain the CMs' cold bias. In the PI scenario, CMs agree on the meridional atmospheric enthalpy transport's peak location (around 40°N/S), while discrepancies of ∼20% exist on the intensity. Disagreements on the oceanic transport peaks' location and intensity amount to ∼10° and ∼50%, respectively. In the SRESA1B runs, the atmospheric transport's peak shifts poleward, and its intensity increases up to ∼10% in both hemispheres. In most CMs, the Northern Hemispheric oceanic transport decreases, and the peaks shift equatorward in both hemispheres. The Bjerknes compensation mechanism is active both on climatological and interannual time scales. The total meridional transport peaks around 35° in both hemispheres and scenarios, whereas disagreements on the intensity reach ∼20%. With increased CO2 concentration, the total transport increases up to ∼10%, thus contributing to polar amplification of global warming. Advances are needed for achieving a self-consistent representation of climate as a nonequilibrium thermodynamical system. This is crucial for improving the CMs' skill in representing past and future climate changes. © 2011 by the American Geophysical Union.

Schwarzenbach H.,University of Hamburg
Expert Review of Molecular Diagnostics | Year: 2015

An effective personalized medicine is associated with the ability of identifying cancer patients who respond to anticancer targeted therapies. Therefore, new companion biomarkers that facilitate drug development are urgently needed. Since clinically relevant genetic and epigenetic alterations can be detected in cell-free nucleic acids in the blood circulation of cancer patients, these molecules may be a new promising class of potential liquid biomarkers. They can be obtained in real-time from blood, and their analyses could, consequently, facilitate treatment decisions. Screening of these liquid biopsies may provide information on the aberrant signaling pathway that should be blocked by the chosen targeted therapy. This article will discuss the potential of circulating nucleic acids as therapeutics for overcoming chemotherapeutic resistance in anticancer strategies. © 2015 Informa UK, Ltd.

Ehinger B.V.,University of Osnabruck | Konig P.,University of Osnabruck | Konig P.,University of Hamburg | Ossandon J.P.,University of Osnabruck
Journal of Neuroscience | Year: 2015

The brain is proposed to operate through probabilistic inference, testing and refining predictions about the world. Here, we search for neural activity compatible with the violation of active predictions, learned from the contingencies between actions and the consequent changes in sensory input. We focused on vision, where eye movements produce stimuli shifts that could, in principle, be predicted. We compared, in humans, error signals to saccade-contingent changes of veridical and inferred inputs by contrasting the electroencephalographic activity after saccades to a stimulus presented inside or outside the blind spot. We observed early (<250 ms) and late (>250 ms) error signals after stimulus change, indicating the violation of sensory and associative predictions, respectively. Remarkably, the late response was diminished for blind-spot trials. These results indicate that predictive signals occur across multiple levels of the visual hierarchy, based on generative models that differentiate between signals that originate from the outside world and those that are inferred. © 2015 the authors.

Bringmann T.,University of Hamburg | Weniger C.,Max Planck Institute for Physics
Physics of the Dark Universe | Year: 2012

Weakly interacting massive particles (WIMPs) remain a prime candidate for the cosmological dark matter (DM), even in the absence of current collider signals that would unambiguously point to new physics below the TeV scale. The self-annihilation of these particles in astronomical targets may leave observable imprints in cosmic rays of various kinds. In this review, we focus on gamma rays which we argue to play a pronounced role among the various possible messengers. We discuss the most promising spectral and spatial signatures to look for, give an update on the current state of gamma-ray searches for DM and an outlook concerning future prospects. We also assess in some detail the implications of a potential signal identification for particle DM models as well as for our understanding of structure formation. Special emphasis is put on the possible evidence for a 130 GeV line-like signal that we recently identified in the data of the Fermi gamma-ray space telescope. © 2012 Elsevier B.V.

Frenzel C.,University of Hamburg
Annals of Hepatology | Year: 2014

For the pathologist, the diagnosis of drug induced liver injury (DILI) is challenging, because histopathological features mimic all primary hepatic and biliary diseases, lacking changes that are specific for DILI. Therefore, in any patient of suspected DILI who underwent liver biopsy, the pathologist will assure the clinician that the observed hepatic changes are compatible with DILI, but this information is less helpful due to lack of specificity. Rather, the pathologist should assess liver biopsies blindly, without knowledge of prior treatment by drugs. This will result in a detailed description of the histological findings, associated with suggestions for potential causes of these hepatic changes. Then, it is up to the physician to reassess carefully the differential diagnoses, if not done before. At present, liver histology is of little impact establishing the diagnosis of DILI with the required degree of certainty, and this shortcoming also applies to herb induced liver injury (HILI). To reach at the correct diagnoses of DILI and HILI, clinical and structured causality assessments are therefore better approaches than liver histology results obtained through liver biopsy, an invasive procedure with a low complication rate.

Improvement in therapy for malignant diseases in the oral and maxillofacial (OMF) region rests mainly upon diagnosis at an early stage of the disease. This study performed an analysis of the delays between symptom onset and time taken for patients to seek medical advice and then their subsequent specialist referral to the Department of OMF Surgery at Eppendorf University Hospital. Patients and Methods: The files of 646 patients (males: 451, females: 195) with malignancies of the OMF region who were treated during an interval of 19 years were analysed retrospectively. Results: Localized swelling, pain and alterations of the mucosa were the predominant first signs and symptoms of disease. Stage grouping according to the TNM system (UICC, 1992) revealed advanced stages in the majority of cases (IV: 30%, III: 15%). The majority of patients were referred by residents in OMF surgery (31.7%) and dentists (28.8%) and were hospitalized within 4 months after notification of the first symptoms (66.9%). Conclusion: Both outreach work of public health institutions and continuous education during studies in both medicine and dentistry, and in further education play a key role in reducing diagnostic delay in OMF cancer.

Werner P.,University of Fribourg | Tsuji N.,University of Fribourg | Eckstein M.,University of Hamburg
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

We study the time evolution of the antiferromagnetic order parameter after interaction quenches in the Hubbard model. Using the nonequilibrium dynamical mean-field formalism, we show that the system, after a quench from intermediate to strong interaction, is trapped in a nonthermal state which is reminiscent of a photodoped state and protected by the slow decay of doublons. If the effective doping of this state is low enough, it exhibits robust antiferromagnetic order, even if the system is highly excited and the thermal state is thus expected to be paramagnetic. We comment on the implication of our findings for the stability of nonthermal superconducting states. © 2012 American Physical Society.

Werner P.,University of Fribourg | Eckstein M.,University of Hamburg
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

We study the relaxation properties of the Kondo lattice model using the nonequilibrium dynamical mean-field formalism in combination with the noncrossing approximation. The system is driven out of equilibrium either by a magnetic field pulse, which perturbs the local singlets, or by a sudden quench of the Kondo coupling. For relaxation processes close to thermal equilibrium (after a weak perturbation), the relaxation time increases substantially as one crosses from the local moment regime into the heavy Fermi liquid. A strong perturbation, which injects a large amount of energy, can rapidly transform the heavy Fermi liquid into a local moment state. Upon cooling, the heavy Fermi liquid reappears in a two-stage relaxation, where the first step opens the Kondo gap and the second step corresponds to a slow approach of the equilibrium state via a nonthermal pathway. © 2012 American Physical Society.

Allogeneic hematopoietic stem cell transplantation (SCT) is well accepted as a curative treatment approach for younger patients with myelodysplastic syndrome (MDS) and has become one of the most frequent indications for allogeneic SCT as reported to the Center for International Blood and Marrow Transplant Research. However, MDS patients are usually elderly with a median age of approximately 75 years at diagnosis. Large register studies have confirmed the feasibility of the procedure in elderly MDS patients; and in the register of the European Group for Blood and Marrow Transplantation, one-third of the allogeneic transplant procedures for MDS were performed in 2010 in patients older than 60 years. Despite its curative potential, its role in the treatment of elderly MDS patients is less defined. Because of the inherent complications of the transplantation leading to treatment-related mortality and the risk of relapse, a careful calculation of the benefit for each patient is mandatory, taking into account comorbidities, disease status, donor selection, and effective nontransplant therapies. Prospective multicenter studies are needed to define optimal intensity of the conditioning regimen, timing of transplantation within a treatment algorithm, including drug-based therapies, and posttransplant strategies to reduce the risk of relapse. © 2012 by The American Society of Hematology.

Viebahn J.,Leibniz Institute of Marine Science | Eden C.,University of Hamburg
Ocean Modelling | Year: 2010

The sensitivity of the meridional overturning circulation (MOC) of the Southern Ocean (SO) to wind stress changes is discussed. Using an idealised SO model in both non- and eddy-permitting configurations, we assess the effects of both, coarsening the horizontal resolution and implementing different parameterisations for the lateral eddy diffusivity appropriate to the Gent and McWilliams (1990) parameterisation, K. We find that the MOC is characterised by an eddy-driven part ψ* which generally opposes the wind-driven part and that the increase of the MOC diminishes with amplifying winds, with the possibility that the MOC in the SO may become completely insensitive to wind stress changes. However, for moderate wind stress, the MOC is still significantly increasing in our configuration.The diagnosed lateral eddy diffusivity K in the eddy-permitting version shows strong spatial variability and is increasing with increasing wind stress. Similar to the MOC (but in contrast to ψ*) the increase of K diminishes with amplifying winds. It turns out that a small increase in the isopycnal slopes is also relevant in order to capture the correct sensitivity of ψ* on wind stress. This relation also holds in model configurations with coarser but still eddy-permitting horizontal resolution: decreasing the horizontal resolution decreases K, but increases the isopycnal slopes such that the strength of the MOC including its sensitivity to wind stress is almost unchanged. The parameterisations are able to reproduce the MOC for certain wind stresses, but all parameterisations underestimate the sensitivity of K and thus overestimate the sensitivity of the MOC on wind stress. Our results show that it is indispensable to incorporate the correct sensitivity of K into climate models in order to reproduce the correct sensitivity of the MOC to wind stress and that up-to-date parameterisations for K are only partially successful. © 2010 Elsevier Ltd.

Hausdorf B.,University of Hamburg
Evolution | Year: 2011

New insights in the speciation process and the nature of "species" that accumulated in the past decade demand adjustments of the species concept. The standing of some of the most broadly accepted or most innovative species concepts in the light of the growing evidence that reproductive barriers are semipermeable to gene flow, that species can differentiate despite ongoing interbreeding, that a single species can originate polyphyletically by parallel evolution, and that uniparental organisms are organised in units that resemble species of biparental organisms is discussed. As a synthesis of ideas in existing concepts and the new insights, a generalization of the genic concept is proposed that defines species as groups of individuals that are reciprocally characterized by features that would have negative fitness effects in other groups and that cannot be regularly exchanged between groups upon contact. The benefits of this differential fitness species concept are that it classifies groups that keep differentiated and keep on differentiating despite interbreeding as species, that it is not restricted to specific mutations or mechanisms causing speciation, and that it can be applied to the whole spectrum of organisms from uni- to biparentals. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

Forster S.,University of Hamburg | Apostol L.,European Synchrotron Radiation Facility | Bras W.,European Synchrotron Radiation Facility
Journal of Applied Crystallography | Year: 2010

Scatter is a new software for analysis, modeling and fitting of one-and two-dimensional small-angle scattering data of non-ordered, partially ordered or fully ordered nano-and mesoscale structures. The calculations are based on closed analytical expressions for the scattering intensity, enabling efficient evaluation of form factors and structure factors. The software allows one to sequentially fit large series of scattering curves and scattering patterns automatically. It provides further tools for data loading, beam centering, calibration, zooming, binning, lattice identification, calculation of density profiles and size distributions, and visualization of real-space structures. Presentations of experimental and calculated data can be saved as is for presentations or exported for further graphical or mathematical treatment. © 2010 International Union of Crystallography Printed in Singapore - all rights reserved.

Luo H.,University of Hamburg | Wen C.,University of Rome Tor Vergata
Journal of High Energy Physics | Year: 2016

Abstract: We establish a set of new on-shell recursion relations for amplitudes satisfying soft theorems. The recursion relations can apply to those amplitudes whose additional physical inputs from soft theorems are enough to overcome the bad large-z behaviour. This work is a generalization of the recursion relations recently obtained by Cheung et al. for amplitudes in scalar effective field theories with enhanced vanishing soft behaviours, which can be regarded as a special case of those with non-vanishing soft limits. We apply the recursion relations to tree-level amplitudes in various theories, including amplitudes in the Akulov-Volkov theory and amplitudes containing dilatons of spontaneously-broken conformal symmetry. © 2016, The Author(s).

Yossepowitch O.,Rabin Medical Center | Briganti A.,Vita-Salute San Raffaele University | Eastham J.A.,Sloan Kettering Cancer Center | Epstein J.,Johns Hopkins Hospital | And 3 more authors.
European Urology | Year: 2014

Context The clinical significance of positive surgical margins (PSMs) in radical prostatectomy (RP) specimens and the management of affected patients remain unclear. Objective To address pitfalls in the pathologic interpretation of margin status; provide an update on the incidence, predictors, and long-term oncologic implications of PSMs in the era of robot-assisted laparoscopic RP (RALRP); and suggest a practical evidence-based approach to patient management. Evidence acquisition A systematic review of the literature was performed in April 2013 using Medline/PubMed, Web of Science, and Scopus databases and the Cochrane Database of Systematic Reviews. Studies focusing on PSMs in RP pertinent to the objectives of this review were included. Particular attention was paid to publications within the last 5 yr and those concerning RALRP. Evidence synthesis A total of 74 publications were retrieved. Standardized measures to overcome variability in the pathologic interpretation of surgical margins have recently been established by the International Society of Urological Pathology. The average rate of PSMs in contemporary RALRP series is 15% (range: 6.5-32%), which is higher in men with a more advanced pathologic stage and equivalent to the rate reported in prior open and laparoscopic prostatectomy series. The likelihood of PSMs is strongly influenced by the surgeon's experience irrespective of the surgical approach. Technical modifications using the robotic platform and the role of frozen-section analysis to reduce the margin positivity rate continue to evolve. Positive margins are associated with a twofold increased hazard of biochemical relapse, but their association with more robust clinical end points is controversial. Level 1 evidence suggests that adjuvant radiation therapy (RT) may favorably affect prostate-specific antigen recurrence rates, but whether the therapy also affects systemic progression, prostate cancer-specific mortality, and overall survival remains debatable. Conclusions Although positive margins in prostate cancer are considered an adverse oncologic outcome, their long-term impact on survival is highly variable and largely influenced by other risk modifiers. Adjuvant RT appears to be effective, but further study is required to determine whether early salvage RT is an equivalent alternative. © 2013 European Association of Urology.

Effertz T.,University of Hamburg | Mann K.,University of Heidelberg
European Neuropsychopharmacology | Year: 2013

Recent publications calculated an annual prevalence of 38% of the population within the European Union having a "disorder of the brain" including substance use disorders (SUD) (Wittchen et al., 2011). The overall economic burden was estimated at 789 billion € (Gustavsson et al., 2011). While these calculations included alcohol dependence, harmful use of alcohol, a common ICD-10 diagnosis, was not considered appropriately. Tobacco related figures were completely left out. We hence estimated burden and costs of these diagnoses for the European Union by extrapolating basic figures from Germany, which have average proportions of alcohol and tobacco related consumption and prevalence rates. Several German Data sets were used to estimate prevalence, disability adjusted life years (DALYs) and Cost-of-Illness for alcohol and tobacco use disorders in Germany. Results were obtained by focussing on the burden of SUD including well-known comorbidities. Results were then extrapolated to the European level. Compared with the earlier estimations DALYs increased from 2.8 million to over 6.6 million for SUDs. Costs augmented from 65.68 billion € PPP to about 350 billion € PPP. We discuss the robustness and validity of our findings under different assumptions and with regard to methodology. We further took into account that in the new DSM 5 alcohol abuse and alcohol dependence - and similar tobacco - will be collapsed into one category of "alcohol related disorder". If added to the burden and cost calculations the substance use disorders rank on top of all disorders of the brain in Europe. Regardless of the calculation procedure our figures represent lower estimates and have to be regarded as conservative approaches. © 2012 Elsevier B.V. and ECNP.

David N.,University of Hamburg
Frontiers in Human Neuroscience | Year: 2012

The sense that I am the author of my own actions, including the ability to distinguish my own from other people's actions, is a fundamental building block of our sense of self, on the one hand, and successful social interactions, on the other. Using cognitive neuroscience techniques, researchers have attempted to elucidate the functional basis of this intriguing phenomenon, also trying to explain pathological abnormalities of action awareness in certain psychiatric and neurological disturbances. Recent conceptual, technological, and methodological advances suggest several interesting and necessary new leads for future research on the neuroscience of agency. Here I will describe new frontiers for the field such as the need for novel and multifactorial paradigms, anatomically plausible network models for the sense of agency, investigations of the temporal dynamics during agentic processing and ecologically valid virtual reality (VR) applications. © 2012 David.

Eden C.,University of Hamburg
Journal of Physical Oceanography | Year: 2012

Three alternative methods of averaging the general conservation equation of a fluid property in a turbulent flow in the Boussinesq approximation are compared: Lagrangian, residual, and isopycnal (or semi-Lagrangian) mean. All methods differentiate consistently but in different ways between effects of advection and irreversible changes of the average property. Because the three average properties differ, the mean transport velocities and the mean irreversible changes in the mean conservation equation differ in general. The Lagrangian and the semi-Lagrangian (or isopycnal) mean frameworks are shown to be approximately equivalent only for weak irreversible changes, small amplitudes of the turbulent fluctuations, and particle excursion predominantly along the mean property gradient. In that case, the divergent Stokes velocity of the Lagrangian mean framework can be replaced in the Lagrangian mean conservation equation by a nondivergent, three-dimensional version of the quasi-Stokes velocity of T. J. McDougall and P. C. McIntosh, for which a closed analytical form for the streamfunction in terms of Eulerian mean quantities is given. © 2012 American Meteorological Society.

Kroenke K.,University of Indianapolis | Spitzer R.L.,Columbia University | Williams J.B.W.,Columbia University | Lowe B.,University of Hamburg
General Hospital Psychiatry | Year: 2010

Background: Depression, anxiety and somatization are the most common mental disorders in primary care as well as medical specialty populations; each is present in at least 5-10% of patients and frequently comorbid with one another. An efficient means for measuring and monitoring all three conditions would be desirable. Methods: Evidence regarding the psychometric and pragmatic characteristics of the Patient Health Questionnaire (PHQ)-9 depression, generalized anxiety disorder (GAD)-7 anxiety and PHQ-15 somatic symptom scales are synthesized from two sources: (1) four multisite cross-sectional studies (three conducted in primary care and one in obstetric-gynecology practices) comprising 9740 patients, and (2) key studies from the literature that have studied these scales. Results: The PHQ-9 and its abbreviated eight-item (PHQ-8) and two-item (PHQ-2) versions have good sensitivity and specificity for detecting depressive disorders. Likewise, the GAD-7 and its abbreviated two-item (GAD-2) version have good operating characteristics for detecting generalized anxiety, panic, social anxiety and post-traumatic stress disorder. The optimal cutpoint is ≥10 on the parent scales (PHQ-9 and GAD-7) and ≥3 on the ultra-brief versions (PHQ-2 and GAD-2). The PHQ-15 is equal or superior to other brief measures for assessing somatic symptoms and screening for somatoform disorders. Cutpoints of 5, 10 and 15 represent mild, moderate and severe symptom levels on all three scales. Sensitivity to change is well-established for the PHQ-9 and emerging albeit not yet definitive for the GAD-7 and PHQ-15. Conclusions: The PHQ-9, GAD-7 and PHQ-15 are brief well-validated measures for detecting and monitoring depression, anxiety and somatization. © 2010.

Zhu R.,University of Gottingen | Lubben J.,University of Gottingen | Dittrich B.,University of Hamburg | Clever G.H.,University of Gottingen
Angewandte Chemie - International Edition | Year: 2015

A simple self-assembled [Pd2L4] coordination cage consisting of four carbazole-based ligands was found to dimerize into the interpenetrated double cage [3X@Pd4L8] upon the addition of 1.5 equivalents of halide anions (X = Cl-, Br-). The halide anions serve as templates, as they are sandwiched by four PdII cations and occupy the three pockets of the entangled cage structure. The subsequent addition of larger amounts of the same halide triggers another structural conversion, now yielding a triply catenated link structure in which each PdII node is trans-coordinated by two pyridine donors and two halide ligands. This simple system demonstrates how molecular complexity can increase upon a gradual change of the relative concentrations of reaction partners that are able to serve different structural roles. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA.

Kniehl B.A.,University of Hamburg
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014

We consider a mixed system of unstable Majorana fermions in a general parity-nonconserving theory and renormalize its propagator matrix to all orders in the pole scheme, in which the squares of the renormalized masses are identified with the complex pole positions and the wave-function renormalization matrices are adjusted in compliance with the Lehmann-Symanzik-Zimmermann reduction formalism. In contrast to the case of unstable Dirac fermions, the wave-function renormalization matrices of the in and out states are uniquely fixed, while they again bifurcate in the sense that they are no longer related by pseudo-Hermitian conjugation. We present closed analytic expressions for the renormalization constants in terms of the scalar, pseudoscalar, vector, and pseudovector parts of the unrenormalized self-energy matrix, which is computable from the one-particle-irreducible Feynman diagrams of the flavor transitions, as well as their expansions through two loops. In the case of stable Majorana fermions, the well-known one-loop results are recovered. © 2014 American Physical Society.

Eckstein M.,University of Hamburg | Werner P.,University of Fribourg
Physical Review Letters | Year: 2014

We use inhomogeneous nonequilibrium dynamical mean-field theory to investigate the spreading of photoexcited carriers in Mott insulating heterostructures with strong internal fields. Antiferromagnetic correlations are found to affect the carrier dynamics in a crucial manner: An antiferromagnetic spin background can absorb energy from photoexcited carriers on an ultrafast time scale, thus enabling fast transport between different layers and the separation of electron and holelike carriers, whereas in the paramagnetic state, carriers become localized in strong fields. This interplay between charge and spin degrees of freedom can be exploited to control the functionality of devices based on Mott insulating heterostructures with polar layers, e.g., for photovoltaic applications. © 2014 American Physical Society.

Bringmann T.,University of Oslo | Vollmann M.,University of Hamburg | Weniger C.,University of Amsterdam
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014

The apparent gamma-ray excess in the Galactic center region and inner Galaxy has attracted considerable interest, notably because both its spectrum and its radial distribution are consistent with an interpretation in terms of annihilating dark matter particles with a mass of about 10-40 GeV. We confront such an interpretation with an updated compilation of various indirect dark matter detection bounds, which we adapt to the specific form required by the observed signal. We find that cosmic-ray positron data strongly rule out dark matter annihilating to light leptons, or "democratically" to all leptons, as an explanation of the signal. Cosmic-ray antiprotons, for which we present independent and significantly improved limits with respect to previous estimates, are already in considerable tension with dark matter (DM) annihilation to any combination of quark final states; the first set of AMS-02 data will thus be able to rule out or confirm the DM hypothesis with high confidence. For reasonable assumptions about the magnetic field in the Galactic center region, radio observations independently put very severe constraints on a DM interpretation of the excess, in particular for all leptonic annihilation channels. © 2014 American Physical Society.

Chakraborty S.,Max Planck Institute for Physics | Mirizzi A.,University of Hamburg
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014

It has been recently discovered that removing the axial symmetry in the "multiangle effects" associated with the neutrino-neutrino interactions for supernova (SN) neutrinos, a new multi-azimuthal-angle (MAA) instability will trigger flavor conversions in addition to the ones caused by the bimodal and multi-zenith-angle (MZA) instabilities. We investigate the dependence of the MAA instability on the original SN neutrino fluxes, performing a stability analysis of the linearized neutrino equations of motion. We compare these results with the numerical evolution of the SN neutrino nonlinear equations, looking at a local solution along a specific line of sight, under the assumption that the transverse variations of the global solution are small. We also assume that self-induced conversions are not suppressed by large matter effects. We show that the pattern of the spectral crossings (energies where Fνe=Fνx and Fν̄e=Fν̄x) is crucial in determining the impact of MAA effects on the flavor evolution. For neutrino spectra with a strong excess of νe over ν̄e, presenting only a single crossing, MAA instabilities will trigger new flavor conversions in normal mass hierarchy. In our simplified flavor evolution scheme, these will lead to spectral swaps and splits analogous to what is produced in inverted hierarchy by the bimodal instability. Conversely, in the presence of spectra with a moderate flavor hierarchy, having multiple crossing energies, MZA effects will produce a sizable delay in the onset of the flavor conversions, inhibiting the growth of the MAA instability. In this case, the splitting features for the oscillated spectra in both the mass hierarchies are the ones induced by the only bimodal and MZA effects. © 2014 American Physical Society.

White T.A.,German Electron Synchrotron | Barty A.,German Electron Synchrotron | Stellato F.,German Electron Synchrotron | Holton J.M.,University of California at San Francisco | And 6 more authors.
Acta Crystallographica Section D: Biological Crystallography | Year: 2013

A processing pipeline for diffraction data acquired using the 'serial crystallography' methodology with a free-electron laser source is described with reference to the crystallographic analysis suite CrystFEL and the pre-processing program Cheetah. A detailed analysis of the nature and impact of indexing ambiguities is presented. Simulations of the Monte Carlo integration scheme, which accounts for the partially recorded nature of the diffraction intensities, are presented and show that the integration of partial reflections could be made to converge more quickly if the bandwidth of the X-rays were to be increased by a small amount or if a slight convergence angle were introduced into the incident beam.

Alix-Panabieres C.,Montpellier University Hospital Center | Alix-Panabieres C.,Institut Universitaire de France | Pantel K.,University of Hamburg
Lab on a Chip - Miniaturisation for Chemistry and Biology | Year: 2014

Hematogeneous tumor cell dissemination is a key step in cancer progression. The detection of CTCs in the peripheral blood of patients with solid epithelial tumors (e.g., breast, prostate, lung and colon cancer) holds great promise, and many exciting technologies have been developed over the past years. However, the detection and molecular characterization of circulating tumor cells (CTCs) remain technically challenging. The identification and characterization of CTCs require extremely sensitive and specific analytical methods, which are usually a combination of complex enrichment and detection procedures. CTCs occur at very low concentrations of one tumor cell in the background of millions of normal blood cells and the epithelial-mesenchymal plasticity of CTCs can hamper their detection by the epithelial markers used in current CTC assays. In the present review, we summarize current methods for the enrichment and detection of CTCs and discuss the key challenges and perspectives of CTC analyses within the context of improved clinical management of cancer patients. This journal is © 2014 The Royal Society of Chemistry.

Shokr M.,Environment Canada | Kaleschke L.,University of Hamburg
Remote Sensing of Environment | Year: 2012

Ice concentration retrieved from spaceborne passive microwave observations is a prime input to operational sea ice monitoring programs, numerical weather prediction and global climate models. However, it is usually underestimated by existing algorithms due to surface conditions, especially in case of young ice types. Evaluation of those algorithms identifies errors in concentration estimates but does not necessarily link them to the adverse surface conditions. The present study is an attempt to establish those links for young ice (< 25 cm) thick. It uses measurements of microwave emission from artificially grown sea ice in an outdoor tank and calculates ice concentration using five established algorithms: NT, Bootstrap (BSA), NT2, ASI and ECICE. Since the actual concentration is known (100%), then any deviation from this value is considered an error and can be linked to the observed surface conditions, which are usually caused by weather events. Those conditions were acquired on hourly or daily basis. Results identify key conditions that lead to underestimation of ice concentration. They include surface refreezing, slush, snow settling following fresh snowfall, and falling precipitation in different forms. The study shows also that NT and NT2 are most affected by surface processes while BSA performs better. ASI is much less affected because it uses the high frequency channel (e.g. SSM/I 85. GHz), which is sensitive only to processes within the top snow layer. ECICE, with its probabilistic and ensemble approach shows also good results under most surface conditions. Dry or wet snow does not lead to significant difference in ice concentration estimate. The study also aims at validation of ECICE. © 2012 Elsevier Inc.

Besiou M.,University of Hamburg | Van Wassenhove L.N.,INSEAD
Production and Operations Management | Year: 2015

Companies seek sustainability by combining the quest for profitability with the pursuit of social responsibility. Since socially responsible operations are characterized by the presence of multiple stakeholders with conflicting goals, applying classical optimization models would seem premature; we first need to capture the behavior of the entire system before attempting to optimize sub-systems to ensure that we focus on the ones driving the behavior of interest. Alternative methodologies are required if we are to gain insight into the most important drivers of socially responsible operations in order to apply traditional operations research (OR)/management science (MS) models correctly. This study presents an umbrella approach which combines different methodologies to tackle the complexity, unfamiliar context, and counter-intuitive behavior of socially responsible operations at the overall system level. © 2015 Production and Operations Management Society.

Hack T.-P.,University of Hamburg | Moretti V.,University of Trento
Journal of Physics A: Mathematical and Theoretical | Year: 2012

We review a few rigorous and partly unpublished results on the regularization of the stress-energy in quantum field theory on curved spacetimes: (1) the symmetry of the Hadamard/Seeley-DeWitt coefficients in smooth Riemannian and Lorentzian spacetimes, (2) the equivalence of the local -function and the Hadamard-point-splitting procedure in smooth static spacetimes and (3) the equivalence of theDeWitt-Schwinger- and theHadamard-point-splitting procedure in smooth Riemannian and Lorentzian spacetimes. © 2012 IOP Publishing Ltd.

Han H.,Humboldt University of Berlin | Schacht M.,University of Hamburg
Journal of Combinatorial Theory. Series B | Year: 2010

A classic result of G.A. Dirac in graph theory asserts that for n ≥ 3 every n-vertex graph with minimum degree at least n / 2 contains a spanning (so-called Hamilton) cycle. G.Y. Katona and H.A. Kierstead suggested a possible extension of this result for k-uniform hypergraphs. There a Hamilton cycle of an n-vertex hypergraph corresponds to an ordering of the vertices such that every k consecutive (modulo n) vertices in the ordering form an edge. Moreover, the minimum degree is the minimum (k - 1)-degree, i.e. the minimum number of edges containing a fixed set of k - 1 vertices. V. Rödl, A. Ruciński, and E. Szemerédi verified (approximately) the conjecture of Katona and Kierstead and showed that every n-vertex, k-uniform hypergraph with minimum (k - 1)-degree (1 / 2 + o (1)) n contains such a tight Hamilton cycle. We study the similar question for Hamilton ℓ-cycles. A Hamilton ℓ-cycle in an n-vertex, k-uniform hypergraph (1 ≤ ℓ < k) is an ordering of the vertices and an ordered subset of the edges such that each such edge corresponds to k consecutive (modulo n) vertices and two consecutive edges intersect in precisely ℓ vertices. We prove sufficient minimum (k - 1)-degree conditions for Hamilton ℓ-cycles if ℓ < k / 2. In particular, we show that for every ℓ < k / 2 every n-vertex, k-uniform hypergraph with minimum (k - 1)-degree (1 / (2 (k - ℓ)) + o (1)) n contains such a loose Hamilton ℓ-cycle. This degree condition is approximately tight and was conjectured by D. Kühn and D. Osthus (for ℓ = 1), who verified it when k = 3. Our proof is based on the so-called weak regularity lemma for hypergraphs and follows the approach of V. Rödl, A. Ruciński, and E. Szemerédi. © 2009 Elsevier Inc. All rights reserved.

Panes B.,University of Hamburg
European Physical Journal C | Year: 2012

We study a framework where the hypothesis of a minimum length in space-time is complemented with the notion of reference frame invariance. It turns out natural to interpret the action of the obtained reference frame transformations in the context of doubly special relativity. As a consequence of this formalism we find interesting connections between the minimum length properties and the modified velocity-energy relation for ultra-relativistic particles. For example, we can predict the ratio between the minimum lengths in space and time using the results from OPERA on superluminal neutrinos. © 2012 Springer-Verlag / Società Italiana di Fisica.

Muhlhauser I.,University of Hamburg
Deutsche Zeitschrift fur Onkologie | Year: 2013

Mammography screening has been evaluated in large randomized-controlled trials. A Cochrane review has concluded that mammography screening achieves a relative reduction in breast cancer mortality of 15%. This translates to one prevented breast cancer death over 10 years among 2000 women invited to biannual mammography screening at age 50. However, mammography screening leads to the detection and treatment of cancers that would never have been found were it not for the screening (overdiagnosis and overtreatment). According to the Cochrane review screening thus increases the incidence of breast cancer, by about 30%, which in turn leads to more therapies (surgery, radiation and chemotherapy). Over ten years after starting mammography at age 50, 10 additional women out of 2000 will be diagnosed with breast cancer. Without screening, these women would not have had a diagnosis. Over the same ten years (5 screening rounds), about one in five women will have at least one mammography result which necessitates further diagnostic workup which may cause psychological distress. Furthermore, even when mammography screening is implemented, approx. 20 to 30% breast cancer patients will not be diagnosed by the screening but between screening rounds. Quality assurance measures may reduce the harms of mammography screening. The information and knowledge of the population about benefits and harms of mammography screening is inadequate in that the benefits are overestimated and the harms underestimated. Women have an ethical right to receive adequate evidence-based information in order to make an informed decision whether to attend mammography screening.

Diel R.,Hannover Medical School | Loddenkemper R.,German Central Committee Against Tuberculosis | Nienhaus A.,University of Hamburg
Chest | Year: 2012

Background: Given the current lack of effective vaccines against TB, the accuracy of screening tests for determining or excluding latent TB infection (LTBI) is decisive in effective TB control. This meta-analysis critically appraises studies investigating the positive and the negative predictive value (PPV and NPV, respectively) from a test-determined LTBI state for progression to active TB of interferon-γ release assays (IGRAs) and the tuberculin skin test (TST). Methods: We searched MEDLINE, EMBASE, and Cochrane bibliographies for relevant articles. After qualitative evaluation, the PPV and NPV for progression of commercial and "in-house"IGRAs and the TST for persons not receiving preventive treatment in the context of the respective IGRA studies were pooled using both a fixed and a random-effect model. Weighted rates were calculated for all study populations and for groups solely at high risk of TB development. Results: The pooled PPV for progression for all studies using commercial IGRAs was 2.7% (95% CI, 2.3%-3.2%) compared with 1.5% (95% CI, 1.2%-1.7%) for the TST (P<.0001). PPV increased to 6.8% (95% CI, 5.6%-8.3%) and 2.4% (95% CI, 1.9%-2.9%) for the IGRAs and the TST, respectively, when only high-risk groups were considered (P<.0001). Pooled values of NPV for progression for both IGRAs and the TST were very high, at 99.7% (95% CI, 99.5%-99.8%) and 99.4% (95% CI, 99.2%-99.5%), respectively, although they were significantly higher for IGRAs (P<.01). Conclusions: Commercial IGRAs have a higher PPV and NPV for progression to active TB compared with those of the TST, especially when performed in high-risk persons. © 2012 American College of Chest Physicians.

Cowie M.R.,Imperial College London | Woehrle H.,ResMed | Woehrle H.,Sleep and Ventilation Center Blaubeuren | Wegscheider K.,University of Hamburg | And 8 more authors.
New England Journal of Medicine | Year: 2015

BACKGROUND Central sleep apnea is associated with poor prognosis and death in patients with heart failure. Adaptive servo-ventilation is a therapy that uses a noninvasive ventilator to treat central sleep apnea by delivering servo-controlled inspiratory pressure support on top of expiratory positive airway pressure. We investigated the effects of adaptive servo-ventilation in patients who had heart failure with reduced ejection fraction and predominantly central sleep apnea. METHODS We randomly assigned 1325 patients with a left ventricular ejection fraction of 45% or less, an apnea-hypopnea index (AHI) of 15 or more events (occurrences of apnea or hypopnea) per hour, and a predominance of central events to receive guideline-based medical treatment with adaptive servo-ventilation or guidelinebased medical treatment alone (control). The primary end point in the time-toevent analysis was the first event of death from any cause, lifesaving cardiovascular intervention (cardiac transplantation, implantation of a ventricular assist device, resuscitation after sudden cardiac arrest, or appropriate lifesaving shock), or unplanned hospitalization for worsening heart failure. RESULTS In the adaptive servo-ventilation group, the mean AHI at 12 months was 6.6 events per hour. The incidence of the primary end point did not differ significantly between the adaptive servo-ventilation group and the control group (54.1% and 50.8%, respectively; hazard ratio, 1.13; 95% confidence interval [CI], 0.97 to 1.31; P = 0.10). All-cause mortality and cardiovascular mortality were significantly higher in the adaptive servo-ventilation group than in the control group (hazard ratio for death from any cause, 1.28; 95% CI, 1.06 to 1.55; P = 0.01; and hazard ratio for cardiovascular death, 1.34; 95% CI, 1.09 to 1.65; P = 0.006). CONCLUSIONS Adaptive servo-ventilation had no significant effect on the primary end point in patients who had heart failure with reduced ejection fraction and predominantly central sleep apnea, but all-cause and cardiovascular mortality were both increased with this therapy. (Funded by ResMed and others; SERVE-HF ClinicalTrials.gov number, NCT00733343.). © 2015 Massachusetts Medical Society. All rights reserved.

Rasche L.,University of Hamburg
International Journal of Biodiversity Science, Ecosystems Services and Management | Year: 2014

The climate is changing, yet to which degree and in what pattern remains uncertain in many areas. In forest science, mainly impacts of long-term mean changes in temperature and precipitation distributions are studied. This paper therefore presents a sensitivity analysis to determine the importance of accounting for variability changes. A 10*10 matrix of different mean annual temperatures and precipitation sums is set up, covering the temperate forest zone of Europe, and the current level of several ecosystem services (ES) is calculated. Subsequently, mean and variability of temperature and precipitation distributions are changed in different steps, and new ES levels calculated. The results show that for the study of climate change impacts on forest ES, climate parameter variability is of secondary importance. The trends are well represented with scenarios of mean climate parameter changes only; however, on moisture-limited and heat-stressed sites impacts of changes in variability gain in importance. Most of these impacts are negative, and can be observed not only in monocultures already at their physiological limit, but also in diverse stands. Different ES, however, show different sensitivities towards changes in mean and variability, underlining the need to develop adaptation measures tailored to the sites and ES of interest. © 2014 © 2014 Taylor & Francis.

Kehr J.,University of Hamburg
Frontiers in Plant Science | Year: 2013

Plants frequently have to cope with environments with sub-optimal mineral nutrient availability. Therefore they need to constantly sense changes of ion concentrations in their environment. Nutrient availabilities and needs have to be tightly coordinated between organs to ensure a balance between uptake and demand for metabolism, growth, reproduction, and defense reactions. To this end information about the nutrient status has to flow from cell-to-cell, but also between distant organs via the long-distance transport tubes to trigger adaptive responses. This systemic signaling between roots and shoots is required to maintain mineral nutrient homeostasis in the different organs under varying environmental conditions. Recent results begin to shed light on the molecular components of the complex long-distance signaling pathways and it has been proposed that systemic signals can be transported through the xylem as well as via the phloem. Several molecules, including nutrients, hormones, sugars, and small RNAs have been suggested to be involved in systemic communication over long distance (Liu et al., 2009). Recent research has shown that in the case of mineral nutrients, the nutrients themselves, but also macromolecules like micro RNAs (miRNAs) can act as important information transmitters. The following review will summarize the current knowledge about phloem-mediated systemic signaling by miRNAs during ion nutrient allocation and adaptation to mineral nutrient deprivation, concentrating on the well-analyzed responses to a lack of potassium, sulfur, and copper. © 2013 Kehr.

Arnold D.,Tumor Biology Center | Stein A.,University of Hamburg
Drugs | Year: 2013

In this review article we discuss the evolution of second-line treatment options for patients with metastatic colorectal cancer (mCRC). The benefits of second-line chemotherapy have been established for some time, but in the last decade a number of trials have evaluated combinations of irinotecan- and oxaliplatin-based chemotherapy with molecular-targeted agents; e.g., vascular endothelial growth factor (VEGF)-targeting agents (bevacizumab, aflibercept), epidermal growth factor receptor antibodies (cetuximab, panitumumab), and tyrosine kinase inhibitors (vatalanib). Recent developments include the availability of the new VEGF-targeted agent aflibercept and the new concept of continuing bevacizumab after failure of first-line bevacizumab, which is likely to become a new treatment option in the second-line setting. Choosing the most appropriate second-line treatment regimen for mCRC patients remains a complex issue. All of the currently available molecular-targeted agents seem to be active even after patients have received a bevacizumab-based first-line regimen. Overall, the selection of second-line treatment for mCRC depends on several variables and should be determined taking into account the patient's performance and disease status. © 2013 Springer International Publishing Switzerland.

Teschke R.,Goethe University Frankfurt | Wolff A.,Friedrich - Schiller University of Jena | Frenzel C.,University of Hamburg | Schulze J.,Goethe University Frankfurt
Alimentary Pharmacology and Therapeutics | Year: 2014

Background Although evidence for their therapeutic efficacy is limited, herbal traditional Chinese medicine (TCM) preparations increasingly gain popularity. In contrast to other herbal products, adverse effects by herbal TCM including liver toxicity were rarely reported. In recent years, more cases were published, providing new clinical challenges. Aim To summarise comprehensively the literature on herbal TCM hepatotoxicity since 2011. Methods PubMed was searched using key words related to TCM, the results were restricted to full English-language publications and abstracts published since 2011. In addition, the database of the National Institutes of Health (NIH) and LiverTox was accessed under the topic 'Drug record: Chinese and other Asian herbal medicines'. Results Since 2011, new case reports and case series provided evidence for herbal hepatotoxicity by TCM, focusing on nine TCM herbal mixtures and four individual TCM herbs with potential health hazards. These were the TCM products Ban Tu Wan, Chai Hu, Du Huo, Huang Qin, Jia Wei Xia Yao San, Jiguja, Kamishoyosan, Long Dan Xie Gan Tang, Lu Cha, Polygonum multiflorum products, Shan Chi, 'White flood' containing the herbal TCM Wu Zhu Yu and Qian Ceng Ta, and Xiao Chai Hu Tang. Other developments include the establishment of a new and early diagnostic serum marker for hepatotoxicity caused by pyrrolizidine alkaloids, assessed using ultra performance liquid chromatography-mass spectrometry analysis, and new regulatory details to improve herbal TCM product quality and safety. Conclusion Stringent evaluation of the risk/benefit ratio is essential to protect traditional Chinese medicines users from health hazards including liver injury. © 2014 John Wiley & Sons Ltd.

Kohlschutter A.,University of Hamburg | Eichler F.,Harvard University
Expert Review of Neurotherapeutics | Year: 2011

Leukodystrophies are white matter disorders that are genetic in nature. In the young, they represent an important cause of progressive neurological disability. They are frequently recognized on MRI, but their identification remains a challenge. Their diagnosis is important for prognostication, palliative and experimental treatment, as well as family screening. The diagnostic strategy rests upon clinical clues and MRI patterns, complemented by appropriately selected electrophysiological and laboratory testing. Considerable overlap exists between white and gray matter disease, as neuronal degeneration will result in myelin loss. An understanding of the pathophysiology and natural disease evolution is necessary to understand the risks and benefits of experimental and palliative treatments. © 2011 Alfried Kohlschütter.

Leichsenring F.,Justus Liebig University | Rabung S.,University of Hamburg
British Journal of Psychiatry | Year: 2011

Background: Dose-effect relationship data suggest that short-term psychotherapy is insufficient for many patients with chronic distress or personality disorders (complex mental disorders). Aims: To examine the comparative efficacy of long-term psychodynamic psychotherapy (LTPP) in complex mental disorders. Method: We conducted a meta-analysis of controlled trials of LTPP fulfilling the following inclusion criteria: therapy lasting for at least a year or 50 sessions; active comparison conditions; prospective design; reliable and valid outcome measures; treatments terminated. Ten studies with 971 patients were included. Results: Between-group effect sizes in favour of LTPP compared with less intensive (lower dose) forms of psychotherapy ranged between 0.44 and 0.68. Conclusions: Results suggest that LTPP is superior to less intensive forms of psychotherapy in complex mental disorders. Further research on long-term psychotherapy is needed, not only for psychodynamic psychotherapy, but also for other therapies.

Strasfeld D.B.,Massachusetts Institute of Technology | Dorn A.,University of Hamburg | Wanger D.D.,Massachusetts Institute of Technology | Bawendi M.G.,Massachusetts Institute of Technology
Nano Letters | Year: 2012

We fabricated planar PbS quantum dot devices with ohmic and Schottky type electrodes and characterized them using scanning photocurrent and photovoltage microscopies. The microscopy techniques used in this investigation allow for interrogation of the lateral depletion width and related photovoltaic properties in the planar Schottky type contacts. Titanium/QD contacts exhibited depletion widths that varied over a wide range as a function of bias voltage, while the gold/QD contacts showed ohmic behavior over the same voltage range. © 2012 American Chemical Society.

Lohse A.,University of Hamburg
Physica D: Nonlinear Phenomena | Year: 2015

Heteroclinic cycles and networks exist robustly in dynamical systems with symmetry. They can be asymptotically stable, and gradually lose this stability through a variety of bifurcations, displaying different forms of non-asymptotic stability along the way. We analyse the stability change in a transverse bifurcation for different types of simple cycles in ℝ4. This is done by first showing how stability of the cycle or network as a whole is related to stability indices along its connections - in particular, essential asymptotic stability is equivalent to all local stability indices being positive. Then we study the change of the stability indices. We find that all cycles of types B and C are generically essentially asymptotically stable after a transverse bifurcation, and that no type B cycle can be almost completely unstable (unlike type C cycles). © 2015 Elsevier B.V.

Hartin A.,University of Hamburg
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2015

The effect on particle physics processes by intense electromagnetic fields in the charge bunch collisions at future lepton colliders is considered. Since the charge bunch fields are tied to massive sources (the e+e- charges), a reference frame is chosen in which the fields appear to be co-propagating. Solutions of the Dirac equation minimally coupled to the electromagnetic fields reasonably associated with two intense overlapping charge bunches are obtained and found to be a Volkov solution with respect to a null 4-vector whose 3-vector part lies in the common propagation direction. These solutions are used within the Furry interaction picture to calculate the beamstrahlung transition rate for electron radiation due to interaction with the electromagnetic fields of two colliding charge bunches. New analytic expressions are obtained and compared numerically with the beamstrahlung in the electromagnetic field of one charge bunch. The techniques developed will be applied to other collider physics processes in due course. © 2015 The Author.

Andreou C.,University of Hamburg | Bozikas V.P.,Aristotle University of Thessaloniki
Current Opinion in Psychiatry | Year: 2013

Purpose of Review: Poor psychosocial functioning in bipolar disorder often persists even after affective symptom remission. Cognitive deficits, which have emerged as a core feature of bipolar disorder in the past few years, are among the factors implicated in adverse psychosocial outcomes of patients suffering from bipolar disorder. This review aims to overview recent literature on the association of neurocognition and psychosocial functioning in bipolar disorder. Recent Findings: Cognitive deficits (mainly general neurocognitive functioning, attention and verbal learning and memory) are important determinants of poor psychosocial functioning in bipolar disorder, although to a lesser extent than in schizophrenia. Although affective symptoms appear to be a more important predictor of functional outcome in symptomatic patients, cognitive deficits also play a significant role, more readily recognizable in euthymic or chronic patients. Summary: Given the importance of cognitive impairments for psychosocial outcomes in bipolar disorder, the development of interventions targeting cognitive impairments is imperative for improving recovery rates and quality of life in patients, even after adequate symptom control. © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins.

ICD patients with narrow QRS, CRT nonresponders, and functional MR patients all have one mechanistic failure mode that is left untreated - The scar left behind following an MI. ICDs, CRTs, and MitraClip implantation are all wellproven therapies, but the Parachute device may address the mechanistic void that remains after each of these therapies has been used and may further improve patients' outcomes. A pooled analysis of 134 subjects was conducted using the first three clinical trials which included subjects with symptomatic ischaemic HF with LV wall motion abnormalities secondary to MI, and an LV ejection fraction less than 40%. The twoyear cumulative mortality rate was 12.9%, with 8.7% in the first year and an increment of 4.2% in the second, which is a 53% reduction as compared to the first year. There is a significant proportion of patients with ischaemic heart failure being excluded from cardiac rhythm management (CRT, etc.), leaving a large treatment gap until mechanical support devices (LVAD) or heart transplantation in progressive heart failure are indicated. Along with other heart failure devices, Parachute may be a useful treatment modality, addressing a mechanistic void in the treatment of this disease. Current data support improvements in haemodynamics, functional capacity, sixminute walk distance, quality of life and a promising decline in mortality two years after Parachute implantation.

Hoppe A.,University of Hamburg
Journal of Occupational Health Psychology | Year: 2011

Despite a steady increase of immigrant workers in Germany in the past decades, occupational health research has only peripherally addressed psychosocial working conditions and immigrant worker well-being. This study has two aims: (1) to investigate differences in psychosocial stressors and resources between immigrant and German low-wage workers, and (2) to examine group differences in their association with well-being using a structural equation modeling multiple group analysis approach. Eighty-nine immigrant and 146 German postmen of a German mail service company were surveyed. Results reveal more stressors in the social work environment for the immigrant workers than for their German coworkers but similar levels of task-related stressors in both groups. Stressors are more strongly associated with psychological distress among the German workers. In terms of resources, job control serves as a resource only among German workers, whereas supervisor and coworker support are more important for immigrant workers. These differences suggest that cultural factors, previous work experiences, and expectations influence the worker's experience of psychosocial working conditions and have a direct impact on worker health. © 2011 American Psychological Association.

Gross J.B.,University of Cincinnati | Wilkens H.,University of Hamburg
Heredity | Year: 2013

The Mexican tetra, Astyanax mexicanus, comprises 29 populations of cave-adapted fish distributed across a vast karst region in northeastern Mexico. These populations have a complex evolutionary history, having descended from 'old' and 'young' ancestral surface-dwelling stocks that invaded the region ∼6.7 and ∼2.8 MYa, respectively. This study investigates a set of captive, pigmented Astyanax cavefish collected from the Micos cave locality in 1970, in which albinism appeared over the past two decades. We combined novel coloration analyses, coding sequence comparisons and mRNA expression level studies to investigate the origin of albinism in captive-bred Micos cavefish. We discovered that albino Micos cavefish harbor two copies of a loss-of-function ocular and cutaneous albinism type II (Oca2) allele previously identified in the geographically distant Pachón cave population. This result suggests that phylogenetically young Micos cavefish and phylogenetically old Pachón cave fish inherited this Oca2 allele from the ancestral surface-dwelling taxon. This likely resulted from the presence of the loss-of-function Oca2 haplotype in the 'young' ancestral surface-dwelling stock that colonized the Micos cave and also introgressed into the ancient Pachón cave population. The appearance of albinism in captive Micos cavefish, caused by the same loss-of-function allele present in Pachón cavefish, implies that geographically and phylogenetically distinct cave populations can evolve the same troglomorphic phenotype from standing genetic variation present in the ancestral taxon. © 2013 Macmillan Publishers Limited. All rights reserved.

In most mutualistic symbioses of insects and intracellular bacteria, the endosymbionts provide additional nutrients to a host that feeds on an unbalanced diet. A strictly vertical transmission leads to co-speciation between the two partners. We have investigated an insect-bacteria relationship with a non-nutritional basis. The reed beetles (Donaciinae) harbor bacteria that produce a secretion used by the larvae for building a cocoon for pupation in mud underwater. The 16S rRNA of the bacteria and the cytochrome c oxidase I and elongation factor 1alpha of the beetles have been partially sequenced. The bacterial and the host phylogeny were highly congruent. Larger taxonomic units (genera) and host species groups/pairs have been recovered in the bacterial phylogeny. The symbiont data still cannot clarify the hitherto unresolved deeper phylogeny of the hosts, which is interpreted as a sign of rapid adaptive radiation of the reed beetles soon after their origin. The rate of sequence evolution among/within host species is discussed. © 2009 Elsevier Inc. All rights reserved.

Baarnhielm S.,Karolinska Institutet | Mosko M.,University of Hamburg
European Psychiatry | Year: 2012

Globalization and cultural diversity challenge mental health care in Europe. Sensitivity to culture in mental health care benefits effective delivery of care to the individual patient and can be a contribution to the larger project of building a tolerant multicultural society. Pivotal for improving cultural sensitivity in mental health care is knowledge in cross-cultural psychiatry, psychology, nursing and related fields among professionals and accordingly training of students and mental health professionals. This paper will give an overview, and a critical examination, of current conceptualisation of cross-cultural mental health training. From German and Swedish experiences the need for crosscultural training and clinical research on evaluation will be presented. © 2012 Elsevier Masson SAS.

Madjet M.E.-A.,German Electron Synchrotron | Vendrell O.,German Electron Synchrotron | Santra R.,German Electron Synchrotron | Santra R.,University of Hamburg
Physical Review Letters | Year: 2011

Acetylene cations [HCCH] + produced in the A2Σg+ state by extreme ultraviolet (XUV) photoionization are investigated theoretically, based on a mixed quantum-classical approach. We show that the decay of the A2Σg+ state occurs via both ultrafast isomerization and nonradiative electronic relaxation. We find a time scale for hydrogen migration and electronic decay of about 60 fs, in good agreement with recent XUV-pump/XUV-probe time-resolved experiments on the same system. Moreover, we predict an efficient vibrational energy redistribution mechanism that quickly transfers excess energy from the isomerization coordinates to slower modes in a few hundred femtoseconds, leading to a partial regeneration of acetylenelike conformations. © 2011 American Physical Society.

Heed T.,University of Hamburg
Current Biology | Year: 2014

A new study takes a significant step towards uncovering the mechanisms that put tactile events on the brain's spatial map by establishing a causal link between attention-related parietal alpha oscillatory activity and the external spatial coding of touch. © 2014 Elsevier Ltd.

Mantau U.,University of Hamburg
Biomass and Bioenergy | Year: 2015

Raw materials assume different forms during their use and thereby develop a multiplicity of effects upon the political environment. This article demonstrates the method of sectoral mass flow analysis using the example of the raw material wood. Under conditions of limited resources, market analysis methods must change from single flow analysis in an open (unlimited) system to interactive flow analysis in a closed (limited) system. The method of the wood resource balance is introduced, with its basic elements of resource monitoring, bottom-up approach, data counterchecking and conversion factors. The method is applicable for manifold research topics. This is shown in three examples. The wood flow analysis represents a total resource assessment including all wood products in all process steps from forest to disposal. Based on the wood flow analysis, calculation schemes show how cascading factors can be calculated on a constant basis. Finally the CO2 effects of total wood use are calculated on a continuous basis.

Wagner F.M.,University of Hamburg
Applied Cardiopulmonary Pathophysiology | Year: 2011

Due to its technically simple and easily reproducible nature cold static preservation is still the current gold standard for myocardial protection in between donor explantation and recipient implantation. It allows "safe" overall ischemic periods of up to 4 hours with a primary graft failure rate less than 2%. Additional measures such as second rinsing or leucocyte depleted in-situ reperfusion allow to extend the ischemic tolerance in ideal donor hearts to 6 hours. Recent technological progress and research improved results of continuous warm, blood based in-vitro perfusion reducing the necessity of myocardial ischemia to the surgical procedures of ex- and implantation. First clinical experiences with this challenging but also very expensive technology indicate its safety and efficacy with at least similar results as cold static preservation even with extended transport times. Due to possible donor evaluation or even resuscitation strategies during ex-vivo perfusion, it offers furthermore promising potential to compensate the ever increasing donor risk profile and could also help to increase availability of trans-plantable donor hearts. As of December 2011 a German multicenter prospective registry study will start with the goal to evaluate efficacy and outcome of this method in 250 heart transplants using donor organs with extended criteria or expected transport times of >3 hours. Expected duration of this project is 2 years and final analyses of collected data will help to clarify if application of this complex and expensive technology is ultimately beneficial and justified.

Krueger N.,University of Hamburg | Sadick N.S.,New York Medical College
Cutis | Year: 2013

Radiofrequency (RF) technology has become a standard treatment in aesthetic medicine with many indications due to its versatility, efficacy, and safety. It is used worldwide for cellulite reduction; acne scar revision; and treatment of hypertrophic scars and keloids, rosacea, and inflammatory acne in all skin types. However, the most common indication for RF technology is the nonablative tightening of tissue to improve skin laxity and reduce wrinkles. Radiofrequency devices are classified as unipolar, bipolar, or multipolar depending on the number of electrodes used. Additional modalities include fractional RF; sublative RF; phase-controlled RF; and combination RF therapies that apply light, massage, or pulsed electromagnetic fields (PEMFs). This article reviews studies and case series on these devices. Radiofrequency technology for aesthetic medicine has seen rapid advancements since it was used for skin tightening in 2003. Future developments will continue to keep RF technology at the forefront of the dermatologist's armamentarium for skin tightening and rejuvenation. © Cutis 2013.

There is increasing evidence that hemodynamic optimization by fluid loading, particularly when performed in the early phase of surgery, is beneficial in high-risk surgery patients: it leads to a reduction in postoperative complications and even to improved long-term outcome. However, it is also true that goal- directed strategies of fluid optimization focusing on cardiac output optimization have not been applied in the clinical routine of many institutions. Reasons are manifold: disbelief in the level of evidence and on the accuracy and practicability of the required monitoring systems, and economics. The FOCCUS trial examined perioperative fluid optimization with a very basic approach: a standardized volume load with 25 ml/kg crystalloids over 6 hours immediately prior to scheduled surgery in high-risk patients. The hypothesis was that this intervention would lead to a compensation of preoperative fluid deficit caused by overnight fasting, and would result in improved perioperative fluid homeostasis with less postoperative complications and earlier hospital discharge. However, the primary study endpoints did not improve significantly. This observation points towards the facts that: firstly, the differentiation between interstitial fluid deficit caused by fasting and intravascular volume loss due to acute blood loss must be recognized in treatment strategies; secondly, the type of fluid replacement may play an important role; and thirdly, protocolized treatment strategies should also always be tailored to suit the patients' individual needs in every individual clinical situation. © 2012 BioMed Central Ltd.

Krom M.D.,University of Leeds | Emeis K.-C.,University of Hamburg | Van Cappellen P.,Georgia Institute of Technology
Progress in Oceanography | Year: 2010

The Eastern Mediterranean Sea (EMS) is a relatively small ocean basin with an unusually high nitrate to phosphate ratio in the deep waters (∼28:1). As a consequence, the typical winter phytoplankton bloom is P rather than N limited. Based on a critical review of the existing evidence, we conclude that the unusual nutrient ratio is due to high N:P values in all the external nutrient inputs to the EMS, coupled to low denitrification rates within the ultra-oligotrophic basin. Thus, we rule out the alternative hypothesis that P limitation in the EMS is due to regionally high rates of diazotrophic N2 fixation. The first line of evidence is a basin-wide nutrient budget, which demonstrates that N removal from the EMS is balanced by N inputs by rivers and atmospheric deposition without the need to invoke additional N2 fixation. The budget further indicates that riverine and atmospheric inputs all have N:P ratios that significantly exceed the Redfield ratio (16:1), and that atmospheric deposition is the major external source of bioavailable N to the EMS. The second line of evidence is a series of recent δ15N measurements showing depleted values in both wet and dry N deposition in the EMS. Hence, the depleted δ15N values of nitrate measured in deep waters of the EMS (2.4±0.1‰) do not reflect N2 fixation, but rather a signal inherited from the nitrate deposited from the atmosphere. The few direct rate determinations of N2 fixation provide the third line of evidence: they show very low activities in both pelagic and coastal areas (<3μmolm-2d-1). A single, extremely high N2 fixation rate (15mmolm-2d-1) reported for the Cyprus warm-core eddy is likely an artifact, as there is no evidence for unusually high numbers of diazotrophs at the time of the rate determination. A nutrient budget for the same warm-core eddy also implies the absence of significant N2 fixation. Overall, the extreme P limitation of the EMS seems to efficiently preclude N2 fixation. Thus, normal N and P cycling processes are operating in the EMS, albeit in a peculiar oceanographic setting that allows deep waters to build-up high N:P ratios, prior to export via the Straits of Sicily. The present-day situation is very different from that prevailing during times in the recent geological past when organic-rich sediments (sapropels) were being deposited. The inferred high rates of N2 fixation during sapropel episodes were probably the result of high rates of denitrification and enhanced P recycling as the oxic-anoxic boundary migrated up into the water column. © 2010 Elsevier Ltd.

Eckl J.,University of Hamburg
Global Social Policy | Year: 2014

This article investigates the rationale that informs the global engagement of private foundations and addresses the question of to what extent and in what way they have the power to (autonomously) shape global social and health policy in line with their convictions even when others disagree or could be expected to disagree. Following a conceptual discussion of power and taking malaria policy as the basis of a historical comparison between the Rockefeller Foundation and the Gates Foundation, the article shows that private foundations are impressively successful in promoting their vision of social and health problems while downplaying potential conflicts and passing over alternatives to their policy prescriptions. Moreover, the foundations can draw on their status as private actors in order to assert autonomy for their own actions even though their ultimate goal is to affect the policies of others - those of the public sector in particular. While the foundations' power is originally based on their monetary resources that often serve as leverage for the mobilization of external resources, their funding of research and interventions helps them in the long run to even develop authority in their field of engagement. With a view to malaria policy it is noteworthy that both foundations analysed were successful in shaping policy in line with their convictions but limited their take on the malaria problem to 'safe issues' and marginalized other perspectives. In particular, they promoted a biomedical rather than a social understanding of health problems, they preferred time-limited investments over sustained spending, and they favoured solutions that promised readily recognizable results. Both foundations brought this biomedical-managerial frame to its logical end when they developed a preoccupation with malaria eradication and shaped global policies accordingly while others pointed at the less obvious dangers and problems of this seemingly persuasive approach. © The Author(s) 2014.

Schafer I.,University of Hamburg | Fisher H.L.,Kings College London
Current Opinion in Psychiatry | Year: 2011

PURPOSE OF REVIEW: To review the current literature on childhood trauma and emerging treatments for posttraumatic stress disorder (PTSD), one of its most prevalent consequences, in patients with psychotic disorders. RECENT FINDINGS: Of patients with psychosis, 40-50% report either childhood sexual abuse or childhood physical abuse, and 11-46% fulfil a diagnosis of PTSD. About one-third of patients report childhood emotional abuse in the absence of other forms of childhood trauma. More robust evidence is mounting to support the role of childhood trauma in the aetiology of psychosis, but more research is needed to understand the underlying mechanisms. Patients with a history of childhood trauma and/or PTSD have a more severe clinical profile compared with those without these experiences, worse overall functioning, and lower remission rates. Research suggests that instruments assessing childhood trauma and PTSD developed for the general population are also appropriate for use among people with psychosis, and trauma-focussed treatments can be used safely and effectively in this group. SUMMARY: Childhood trauma and its consequences are highly prevalent among patients with psychosis and severely affect the course and outcome. Treatment approaches appropriate for this population need to be further evaluated and implemented into routine practice. © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Popp J.,University of Lausanne | Arlt S.,University of Hamburg
Current Opinion in Psychiatry | Year: 2011

PURPOSE OF REVIEW: To give an overview of recent developments in pharmacological treatment options of cognitive as well as behavioural and psychological symptoms of dementia (BPSD) associated with Alzheimer's disease (AD) dementia and mild cognitive impairment due to AD (MCI-AD). RECENT FINDINGS: Knowledge about the efficacy and limitations of the antidementive drugs memantine and cholinesterase inhibitors (ChEIs) in different stages of AD is further expanding. The prediction of treatment response to ChEI and assessment of treatment outcome in the individual patient remain unsolved issues. Commonly prescribed antidepressants have recently failed to be beneficial in depressed AD dementia patients. Clinical trials on new disease-modifying drugs have been disappointing so far. SUMMARY: There is an urgent need for more effective treatment options for cognitive symptoms and BPSD in AD dementia and MCI-AD and for disease-modifying drugs to stop the underlying neurodegenerative process. Recently published new research criteria for the diagnosis of AD enlarge the window for the detection of the disease to early, predementia stages and include biomarkers related to the underlying cerebral AD pathology. In future studies, these criteria will hopefully facilitate the identification of effective drugs in early AD stages. © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Schneider J.M.,University of Hamburg | Michalik P.,University of Greifswald
BMC Evolutionary Biology | Year: 2011

Background: Monogynous mating systems with extremely low male mating rates have several independent evolutionary origins and are associated with drastic adaptations involving self-sacrifice, one-shot genitalia, genital damage, and termination of spermatogenesis immediately after maturation. The combination of such extreme traits likely restricts evolutionary potential perhaps up to the point of making low male mating rates irreversible and hence may constitute an evolutionary dead end. Here, we explore the case of a reversion to multiple mating from monogynous ancestry in golden orb-web spiders, Nephila senegalensis. Results: Male multiple mating is regained by the loss of genital damage and sexual cannibalism but spermatogenesis is terminated with maturation, restricting males to a single loading of their secondary mating organs and a fixed supply of sperm. However, males re-use their mating organs and by experimentally mating males to many females, we show that the sperm supply is divided between copulations without reloading the pedipalps. Conclusion: By portioning their precious sperm supply, males achieve an average mating rate of four females which effectively doubles the maximal mating rate of their ancestors. A heritage of one-shot genitalia does not completely restrict the potential to increase mating rates in Nephila although an upper limit is defined by the available sperm load. Future studies should now investigate how males use this potential in the field and identify selection pressures responsible for a reversal from monogynous to polygynous mating strategies. © 2011 Schneider and Michalik; licensee BioMed Central Ltd.

Volkamer A.,Heidelberg Innovation | Rarey M.,University of Hamburg
Future Medicinal Chemistry | Year: 2014

The amount of known protein structures is continuously growing, exhibited in over 95,000 3D structures freely available via the PDB. Over the last decade, pharmaceutical research has sparked interest in computationally extracting information from this large data pool, resulting in a homology-driven knowledge transfer from annotated to new structures. Studying protein structures with respect to understanding and modulating their functional behavior means analyzing their centers of action. Therefore, the detection and description of potential binding sites on the protein surface is a major step towards protein classification and assessment. Subsequently, these representations can be incorporated to compare proteins, and to predict their druggability or function. Especially in the context of target identification and polypharmacology, automated tools for large-scale target comparisons are highly needed. In this article, developments for automated structure-based target assessment are reviewed and remaining challenges as well as future perspectives are discussed. © 2014 Future Science Ltd.

Boels R.H.,University of Hamburg | Schwinn C.,Albert Ludwigs University of Freiburg
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2011

The consequences of on-shell supersymmetry are studied for scattering amplitudes with massive particles in four dimensions. Using the massive version of the spinor-helicity formalism, the supersymmetry transformations relating products of on-shell states are derived directly from the on-shell supersymmetry algebra for any massive representation. Solutions to the resulting Ward identities can be constructed as functions on the on-shell superspaces that are obtained from the coherent-state method. In simple cases, it is shown that these superspaces allow one to construct explicitly supersymmetric scattering amplitudes. Supersymmetric on-shell recursion relations for tree-level superamplitudes with massive particles are introduced. As examples, simple supersymmetric amplitudes are constructed in Supersymmetric Quantum Chromodynamics (SQCD), the Abelian Higgs model, the Coulomb branch of N=4, QCD with an effective Higgs-gluon coupling and for massive vector-boson currents. © 2011 American Physical Society.

Jedamzik K.,Montpellier University | Sigl G.,University of Hamburg
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2011

Cosmic magnetic fields may be generated during early cosmic phase transition, such as the QCD or electroweak transitions. The magnitude of the remainder of such fields at the present epoch crucially depends on the exponent n of their (initially super-Hubble) large-scale tail, i.e., B λ∼λ-n. It has been claimed that causality requires n=5/2, contrary to much earlier claims of n=3/2. Here we analyze this question in detail. First, we note that contrary to current belief, the large-scale magnetic field tail is not established at the phase transition itself, but rather continuously evolves up to the present epoch. Neglecting turbulent flows we find n=7/2, i.e., very strongly suppressed large-scale fields. However, in the inevitable presence of turbulent flows we find that the large-scale magnetic field tail has sufficient time to evolve to that of the fluid turbulence. For white noise fluid turbulence this yields n=3/2 up to a certain scale and n=5/2 beyond for the magnetic field spectrum. This picture is also not changed when primordial viscosity and fluid flow dissipation is taken into account. Appreciable primordial magnetic fields originating from cosmic phase transitions thus seem possible. © 2011 American Physical Society.

Bergstrom L.,The Oskar Klein Center | Bringmann T.,University of Hamburg | Edsjo J.,The Oskar Klein Center
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2011

We show, by using an extensive sample of viable supersymmetric models as templates, that indirect detection of dark matter through gamma rays may have a large potential for identifying the nature of dark matter. This is, in particular, true also for models that give too weak dark matter-nucleon scattering cross sections to be probed by present and planned direct detection experiments. Also models with a mass scale too high to be accessible at CERN's LHC accelerator may show up in next-generation imaging Cherenkov telescope arrays. Based on our findings, we therefore suggest to view indirect searches as genuine particle physics experiments, complementing other strategies to probe so far unknown regions in the parameter space of e.g. supersymmetric models, and propose a new approach that would make use of telescopes dedicated for dark matter searches. As a concrete example for the potential of such an approach, we consider an array of imaging air Cherenkov telescopes, the Dark Matter Array (DMA), and show that such an experiment could extend present-day limits by several orders of magnitude, reaching a large class of models that would remain undetected in both direct detection experiments and searches at the LHC. In addition, in a sizable part of the parameter space, signals from more than one type of dark matter detection experiment would be possible, something that may eventually be necessary in order to identify the dark matter candidate. © 2011 American Physical Society.