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Antwerp, Belgium

The University of Antwerp is one of the major Belgian universities located in the city of Antwerp. The name is abbreviated as UAntwerp, but sometimes as UA.As of 2014, the University of Antwerp ranks as 170th globally according to Times Higher Education, 205th according to QS World University Rankings and between the 301 and 400th place according to the Academic Ranking of World Universities. Wikipedia.

Pina J.C.,Federal University of Pernambuco | De Souza Silva C.C.,Federal University of Pernambuco | Miloevic M.V.,Federal University of Ceara | Miloevic M.V.,University of Antwerp
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

We investigate the stability of noncomposite fractional vortex states in a mesoscopic two-band superconductor within the two-component Ginzburg-Landau model. Our analysis explicitly takes into account the relationship between the model parameters and microscopic material parameters, such as partial density of states, Fermi velocities and elements of the electron-phonon coupling matrix. We have found that states with different phase winding number in each band (L 1L 2) and fractional flux can exist in many different configurations, including rather unconventional ones where the dominating band carries larger winding number and states where |L 1-L 2|1. We present a detailed analysis of the stability of the observed vortex structures with respect to changing the microscopic parameters, showing that, in the weak coupling case, fractional vortex states can be assessed in essentially the whole range of temperatures and applied magnetic fields in which both bands are active. Finally, we propose an efficient way of increasing the range of parameters for which these fractional vortex states can be stabilized. In particular, our proposal allows for observation of fractional vortex structures in materials with stronger coupling, where those states are forbidden at a homogeneous field. This is accomplished with the help of the stray fields of a suitably prepared magnetic dot placed nearby the superconducting disk. © 2012 American Physical Society.

De Florio V.,University of Antwerp
ASAS'11 - Proceedings of the 8th Workshop on Assurances for Self-Adaptive Systems | Year: 2011

How to build robust-and-evolvable resilient software systems? On the one hand, evolvability implies a system's ability to reach autonomously new, possibly unprecedented conditions and states; on the other hand, resilience and robustness refer to feature persistence in the face of perturbations and changes such as the ones brought about by system evolution. How to address such problem? How to make sure that a software system shall exhibit emerging properties such as reliability or safety irrespective of its environmental conditions and whatever its new configuration may be? In this paper we discuss these problems leveraging from three cases of adaptive software and systems designs. Our conclusions are that the complexity and characteristics of the system components in control of evolution as well as the forms of interaction of the systems with their environments play a key role in the ultimate emergence of sought properties and behaviours. Moreover we highlight how social eco-systems in heterarchical organisation appear to have a stronger resilience and robustness throughout their evolutions. © 2011 ACM.

An electrochemical matairesinol biosensor was fabricated by immobilizing tyrosinase on a poly(thionine)/nafion/multi-walled carbon nanotube composite film. A polymeric film of the redox dye thionine enables the stable immobilization of tyrosinase while acting as a mediator for the enzymatic process has been incorporated into the carbon nanotube/nafion composite film. The immobilization method is based on crosslinking of the tyrosinase layer with an electropolymerized film of poly(thionine). The good homogenization of the electron conductor CNTs in the integrated films provides the possibility of a three-dimensional electron conductive network. The biosensor was characterized by electrochemical impedance spectroscopy and electrochemical characterization. The composite electrode exhibits catalytic activity, high sensitivity, stability and is applicable over a wide range of concentrations from 180 nM to 4.33 μM with a detection limit (LOD) of 37 nM. The obtained results suggest that the developed sensor can be successfully used for the determination of phenolic endocrine disruptors over a concentration range covering their environmental levels.

Bouhy D.,University of Antwerp
Annals of neurology | Year: 2013

Charcot-Marie-Tooth (CMT) neuropathies are inherited neuromuscular disorders caused by a length-dependent neurodegeneration of peripheral nerves. More than 900 mutations in 60 different genes are causative of the neuropathy. Despite significant progress in therapeutic strategies, the disease remains incurable. The increasing number of genes linked to the disease, and their considerable clinical and genetic heterogeneity render the development of these strategies particularly challenging. In this context, cellular and animals models provide powerful tools. Efficient motor and sensory tests have been developed to assess the behavioral phenotype in transgenic animal models (rodent and fly). When these models reproduce a phenotype comparable to CMT, they allow therapeutic approaches and the discovery of modifiers and biomarkers. In this review, we describe the most convincing transgenic rodent and fly models of CMT and how they can lead to clinical trial. We also discuss the challenges that the research, the clinic, and the pharmaceutical industry will face in developing efficient and accessible treatment for CMT patients. Copyright © 2013 American Neurological Association.

Peeters M.,University of Antwerp
Acta gastro-enterologica Belgica | Year: 2010

This paper reviews the research that has been conducted into the use of Sandostatin to control the debilitating symptoms of diarrhea in a number of different etiologies. These are cancer-related diarrheas, including diarrhea related to chemotherapy, radiotherapy, neuroendocrine tumor carcinoid syndrome, vasoactive intestinal peptide-secreting tumors and also non-cancer related diarrhea, including short bowel syndrome, ileo- and jejunostomy, dumping syndrome, graft versus host disease and AIDS-related diarrhea. There is an increasing recognition of the need to balance the cost of care with patient outcome. It is becoming clear that although the cost of a therapeutic regimen with Sandostatin is substantially greater than the current non-specific therapy, the overall cost is potentially greater without the use of Sandostatin for patients with refractory diarrhea due to the inevitable need for further treatment and/or hospitalization with intravenous fluid supplementation. Initial trials and reports from preclinical testing and clinical practice have shown promising results and, although in the majority of cases they strengthen the view taken in the published consensus guidelines for the use of Sandostatin for refractory diarrhea, further, larger scale, comparative clinical trials are required for any evidence-based definition of dosage and efficacy as a treatment or prophylactic agent to combat and control diarrhea.

Loeys B.L.,University of Antwerp
Pediatric endocrinology reviews : PER | Year: 2013

The extracellular matrix (ECM) is a complex entity with structural proteins (such as fibrillins, collagen, elastin), ground substance (proteoglycans), modifying enzymes (ADAMTS, PLOD, lysyloxidases (LOX)) and cytokines that regulate morphogenesis, growth, homeostasis and repair (transforming growth factor-beta [TGF-beta], bone morphogenic protein [BMP]). Over the last decade, the intimate relationship between structural proteins and these growth factors has emerged. The study of the extracellular matrix in human conditions and relevant mouse models is gradually unmasking the key role of these structural molecules in the regulation of the bio-availability of these growth factors. Major progress has been made in the study of the cardiovascular system (1) and the first clues in the skeletal system have emerged. (2) In this review, we will discuss the clinical, molecular, and pathogenic aspects of Marfan syndrome, Loeys-Dietz syndrome and related disorders with emphasis on the role of fibrillins and TGF-beta.

Ieven M.,University of Antwerp | Finch R.,University of Nottingham | Van Belkum A.,bioMerieux
Clinical Microbiology and Infection | Year: 2013

Laboratory-based diagnosis of infectious diseases is evolving quickly. New technologies and new tests are frequently commercialized, and although guidelines for their proper clinical validation do exist, these are often at the national or regional level. Therefore, the guidelines remain open to interpretation, and are not always applied properly. One of the main questions is how a high level of test quality can be maintained by European legislation. How can product quality be reliably and independently assessed and how can the penetration of sub-standard assays in the European market be managed and hopefully prevented? We here propose that local initiatives, including external quality assessment, public health initiatives, and close multidisciplinary collaborations between manufacturers and academic research institutes, may accelerate decision-making. Vigilance in test quality assessment and legal simplification are important key concepts warranting selective use of those diagnostic tests that comply with the highest quality standards. © 2012 The Authors. Clinical Microbiology and Infection © 2012 European Society of Clinical Microbiology and Infectious Diseases.

Baron R.,Universitaetsklinikum Schleswig Holstein | Hans G.,University of Antwerp | Dickenson A.H.,University College London
Annals of Neurology | Year: 2013

Many pain states begin with damage to tissue and/or nerves in the periphery, leading to enhanced transmitter release within the spinal cord and central sensitization. Manifestations of this central sensitization are windup and long-term potentiation. Hyperexcitable spinal neurons show reduced thresholds, greater evoked responses, increased receptive field sizes, and ongoing stimulus-independent activity; these changes probably underlie the allodynia, hyperalgesia, and spontaneous pain seen in patients. Central sensitization is maintained by continuing input from the periphery, but also modulated by descending controls, both inhibitory and facilitatory, from the midbrain and brainstem. The projections of sensitized spinal neurons to the brain, in turn, alter the processing of painful messages by higher centers. Several mechanisms contribute to central sensitization. Repetitive activation of primary afferent C fibers leads to a synaptic strengthening of nociceptive transmission. It may also induce facilitation of non-nociceptive Aβ fibers and nociceptive Aδ fibers, giving rise to dynamic mechanical allodynia and mechanical hyperalgesia. In postherpetic neuralgia and complex regional pain syndrome, for example, these symptoms are maintained and modulated by peripheral nociceptive input. Diagnosing central sensitization can be particularly difficult. In addition to the medical history, quantitative sensory testing and functional magnetic resonance imaging may be useful, but diagnostic criteria that include both subjective and objective measures of central augmentation are needed. Mounting evidence indicates that treatment strategies that desensitize the peripheral and central nervous systems are required. These should generally involve a multimodal approach, so that therapies may target the peripheral drivers of central sensitization and/or the central consequences. © 2013 American Neurological Association.

Verbruggen A.,University of Antwerp
Energy Policy | Year: 2013

Nuclear decision-making is embedded in slowly evolving political, economic and financial institutions. Belgium houses extended nuclear activities, mostly under French control, for example: SUEZ-GDF and EDF own all Belgian nuclear power plants. But a 2003 law mandates the closure of Belgium's nuclear power plants at a service age of 40 years; only force majeure could lift the strict obligation. Opposition to the law argued with climate change danger, financial losses, and loss-of-load risks. The financial issue got interwoven with a fuzzy debate on the definition, height and appropriation of "nuclear rents". As plausible hypothesis is adopted: the prospected transfer of hundreds millions of euro from power companies to the public interest will create public support for life extension. But the nuclear rents discussion had faded in July 2012 when the Belgian government admitted a 10-year life extension for TIHANGE I (962. MW) and imposed the closure of the 2×433. MW DOEL I and II. Loss-of-load risk was the government's only public argument. The opacity of the decision process and its "fifty-fifty" outcome do not allow proper testing of the hypothesis. The case illustrates that politicians cannot bind their followers except through the deployment of alternative power sources. © 2013 Elsevier Ltd.

Reader A.J.,Kings College London | Reader A.J.,Montreal Neurological Institute | Verhaeghe J.,University of Antwerp
Physics in Medicine and Biology | Year: 2014

An overview of the theory of 4D image reconstruction for emission tomography is given along with a review of the current state of the art, covering both positron emission tomography and single photon emission computed tomography (SPECT). By viewing 4D image reconstruction as a matter of either linear or non-linear parameter estimation for a set of spatiotemporal functions chosen to approximately represent the radiotracer distribution, the areas of so-called 'fully 4D' image reconstruction and 'direct kinetic parameter estimation' are unified within a common framework. Many choices of linear and non-linear parameterization of these functions are considered (including the important case where the parameters have direct biological meaning), along with a review of the algorithms which are able to estimate these often non-linear parameters from emission tomography data. The other crucial components to image reconstruction (the objective function, the system model and the raw data format) are also covered, but in less detail due to the relatively straightforward extension from their corresponding components in conventional 3D image reconstruction. The key unifying concept is that maximum likelihood or maximum a posteriori (MAP) estimation of either linear or non-linear model parameters can be achieved in image space after carrying out a conventional expectation maximization (EM) update of the dynamic image series, using a Kullback-Leibler distance metric (comparing the modeled image values with the EM image values), to optimize the desired parameters. For MAP, an image-space penalty for regularization purposes is required. The benefits of 4D and direct reconstruction reported in the literature are reviewed, and furthermore demonstrated with simple simulation examples. It is clear that the future of reconstructing dynamic or functional emission tomography images, which often exhibit high levels of spatially correlated noise, should ideally exploit these 4D approaches. © 2014 Institute of Physics and Engineering in Medicine.

Schattschneider P.,Vienna University of Technology | Schattschneider P.,Ecole Centrale Paris | Stoger-Pollach M.,Vienna University of Technology | Verbeeck J.,University of Antwerp
Physical Review Letters | Year: 2012

A mode converter for electron vortex beams is described. Numerical simulations, confirmed by experiment, show that the converter transforms a vortex beam with a topological charge m=±1 into beams closely resembling Hermite-Gaussian HG 10 and HG 01 modes. The converter can be used as a mode discriminator or filter for electron vortex beams. Combining the converter with a phase plate turns a plane wave into modes with topological charge m=±1. This combination serves as a generator of electron vortex beams of high brilliance. © 2012 American Physical Society.

This article describes a client-centered and experiential psychotherapy approach in which interpersonal issues as well as intrapsychic self-related disturbances of clients with interpersonal trauma are processed through the interaction with an emotionally engaged and empathically attuned therapist. With the helping presence of the therapist, these seriously injured clients start exploring and processing their maladaptive, blocking or overwhelming anxiety and the underlying experiences; and they start experimenting with seeking closeness and intimacy in order to get comfort and reassurance. In doing so, their self becomes stronger, their capacity for self-soothing grows and they begin feeling safer within themselves and in their interpersonal relationships. © 2013 World Association for Person-Centered & Experiential Psychotherapy & Counseling.

Neytsa E.C.,University of Antwerp
Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures | Year: 2012

Nanostructured carbon materials show a tremendous variety in atomic structure, morphology, properties, and applications. As all properties are ultimately determined by the structure of the material, a thorough understanding of the growth mechanisms that give rise to the particular structure is critical. On many occasions, it has been shown that plasma enhanced growth can be strongly beneficial. This review will describe the authors' current understanding of plasma enhanced growth of carbon nanotubes, the prototypical example of nanostructured carbon materials, as obtained from experiments, simulations, and modeling. Specific emphasis is put on where experiments and computational approaches correspond, and where they differ. Also, the current status on simulating PECVD growth of some other carbon nanomaterials is reviewed, including amorphous carbon, graphene, and metallofullerenes. Finally, computational challenges with respect to the simulation of PECVD growth are identified. © 2012 American Vacuum Society.

Schattschneider P.,Vienna University of Technology | Loffler S.,Vienna University of Technology | Stoger-Pollach M.,Vienna University of Technology | Verbeeck J.,University of Antwerp
Ultramicroscopy | Year: 2014

We discuss the feasibility of detecting magnetic transitions with focused electron vortex probes, suggested by selection rules for the magnetic quantum number. We theoretically estimate the dichroic signal strength in the L2,3 edge of ferromagnetic d metals. It is shown that under realistic conditions, the dichroic signal is undetectable for nanoparticles larger than ~1 nm. This is confirmed by a key experiment with nanometer-sized vortices. © 2013 The Authors.

Adams F.,University of Antwerp | Barbante C.,CNR Institute of Neuroscience | Barbante C.,University of Venice
Talanta | Year: 2012

In this tutorial review we give a concise and general overview of the development of imaging analytical techniques from its early stages in the late 1950s up to the present. Analytical techniques that are available for the characterization of the atomic and molecular composition as well as the structure at the bulk level often fail for the analysis of heterogeneous materials. Over the last 50 years a number of specialized analytical techniques were developed - or adapted from existing techniques - that, with time, matured into powerful tools for visualizing structural and compositional heterogeneity in nanotechnology and for the study of natural objects. These techniques evolved first at the microscopic and then the mesoscopic level (the range 100-1,000 nm), and later onto the nanoscopic scale between a few nm and 100 nm, where quantum effects start affecting the properties of materials. © 2012 Elsevier B.V. All rights reserved.

Verbraecken J.,University of Antwerp
Breathe | Year: 2013

Nocturnal polysomnography (PSG) is the most important laboratory technique in the management of sleep-wake disturbances and is considered the "gold standard" [1]. New sensor technologies are entering the field, and rapid development in telecommunications and mobile technology has accelerated the introduction of telemedicine as a viable and reliable option [2]. The present broad review is an amalgam of the current knowledge with proposed new sensors and remote control. The reader should note that not all of the techniques discussed here have strong clinical validation, and this should be considered when purchasing equipment.

Dixon E.,University of Oxford | Hadermann J.,University of Antwerp | Hayward M.A.,University of Oxford
Chemistry of Materials | Year: 2012

Topotactic reduction of La 1-xSr xMnO 3 (0.67 ≤ x ≤1) phases with sodium hydride yields a series of isoelectronic materials of composition La 1-xSr xMnO 3-(0.5+x)/2. Lanthanum rich members of the series (0.67 ≤x ≤0.83) adopt anion deficient perovskite structures with a 6-layer -OTOOT'O- stacking sequence of sheets of octahedra/square-based pyramids (O) and sheets of tetrahedra (T). The strontium rich members of the series (0.83 ≤x ≤1) incorporate "step defects" into this 6-layer structure in which the OTOOT'O stacking sequence is converted into either OOTOOT' or TOOT'OO at a defect plane which runs perpendicular to the [201] lattice plane. The step defects appear to provide a mechanism to relieve lattice strain and accommodate additional anion deficiency in phases with x > 0.83. Magnetization and neutron diffraction data indicate La 1-xSr xMnO 3-(0.5+x)/2 phases adopt antiferromagnetically ordered states at low-temperature in which the ordered arrangement of magnetic spins is incommensurate with the crystallographic lattice. © 2012 American Chemical Society.

Neek-Amal M.,Shahid Rajaee Teacher Training University | Peeters F.M.,University of Antwerp
Journal of Physics Condensed Matter | Year: 2011

We investigate the stability of circular monolayer graphene subjected to a radial load using non-equilibrium molecular dynamics simulations. When monolayer graphene is radially stressed, after some small circular strain (∼0.4%) it buckles and bends into a new bowl-like shape. Young's modulus is calculated from the linear relation between stress and strain before the buckling threshold, which is in agreement with experimental results. The prediction of elasticity theory for the buckling threshold of a radially stressed plate is presented and its results are compared to the one of our atomistic simulation. The Jarzynski equality is used to estimate the difference between the free energy of the non-compressed states and the buckled states. From a calculation of the free energy we obtain the optimum radius for which the system feels the minimum boundary stress. © 2011 IOP Publishing Ltd.

Neek-Amal M.,Shahid Rajaee Teacher Training University | Peeters F.M.,University of Antwerp
Physical Review B - Condensed Matter and Materials Physics | Year: 2011

Using atomistic simulations, we determine the roughness and the thermal properties of a suspended graphane sheet. As compared to graphene, we found that (i) hydrogenated graphene has a larger thermal contraction, (ii) the roughness exponent at room temperature is smaller, i.e., 1.0 versus 1.2 for graphene, (iii) the wavelengths of the induced ripples in graphane cover a wide range corresponding to length scales in the range 30-125 Å at room temperature, and (iv) the heat capacity of graphane is estimated to be 29.32±0.23 J/mol K, which is 14.8% larger than that for graphene, i.e., 24.98±0.14 J/mol K. Above 1500 K, we found that graphane buckles when its edges are supported in the x-y plane. © 2011 American Physical Society.

Peeraer J.,Flemish Association for Development Cooperation and Technical Assistance | Van Petegem P.,University of Antwerp
Evaluation and Program Planning | Year: 2015

Over the last two decades, crucial factors for Information and Communication Technology (ICT) in education have improved significantly in Vietnam. Nevertheless, it is clear that, as in other countries, no educational revolution is taking place. We argue that there is a need for a broad dialogue on the future of ICT in education in Vietnam as discussion of ideas about future possibilities can be instrumental in rationalizing and generating educational change. We explore how a group of key players representing the public and private sector as well as development partners in the field look at the future of ICT in education in the country. Following the Delphi method, these key players assessed in different survey rounds the current situation of ICT in education, identified a series of targets and were asked to assess these targets in respect of their importance. The key players reached a consensus that the purpose of technology integration is to achieve learning goals and enhance learning. However, there is more controversy on targets that could potentially transform education practice in Vietnam. We discuss the value of the Delphi technique and argue for increased participation of all involved stakeholders in policy development on ICT in education. © 2014 Elsevier Ltd.

Moreels T.G.,University of Antwerp
Best Practice and Research: Clinical Gastroenterology | Year: 2012

Roux-en-Y entero-enteric anastomosis of the small bowel is a commonly used surgical technique. However, it excludes the afferent limb and the biliopancreatic system from conventional endoscopic access. Recent data have shown that device-assisted enteroscopy (DAE) allows endoscopic retrograde cholangiopancreatography (ERCP) in these patients with high success rates. Both Double-balloon, short Double-balloon, Single-balloon and Spiral enteroscopy can be used for DAE-ERCP with comparable success. This review highlights the currently available literature data on DAE-ERCP in patients with Roux-en-Y anastomosis, and discusses the clinical aspects and technical difficulties. Although DAE does increase ERCP efficacy in patients with Roux-en-Y anastomosis, it remains a challenging procedure which is open to further improvement. © 2012 Elsevier Ltd. All rights reserved.

Rosenfeld J.V.,Monash University | Maas A.I.,University of Antwerp | Bragge P.,Monash University | Morganti-Kossmann M.C.,Monash University | And 2 more authors.
The Lancet | Year: 2012

Severe traumatic brain injury remains a major health-care problem worldwide. Although major progress has been made in understanding of the pathophysiology of this injury, this has not yet led to substantial improvements in outcome. In this report, we address present knowledge and its limitations, research innovations, and clinical implications. Improved outcomes for patients with severe traumatic brain injury could result from progress in pharmacological and other treatments, neural repair and regeneration, optimisation of surgical indications and techniques, and combination and individually targeted treatments. Expanded classification of traumatic brain injury and innovations in research design will underpin these advances. We are optimistic that further gains in outcome for patients with severe traumatic brain injury will be achieved in the next decade.

The tandem of infrastructure and landscape ecology is increasingly presented as the design strategy par excellence to address the risk society. Staged in explicit contrast to engineering as discipline disrupting natural balance, discourses endorsed by landscape and ecological urbanism propagate a new and improved ‘post-carbon’ and ‘post-Euclidian’ infrastructure. The broad objective of the article is to examine the accuracy of this claim of moving infrastructure from the realm of engineering to urbanism, and appraise the proclaimed methodological shift from determining top-down logics to bottom-up argumentation. In the first part, the recent design culture and techniques are analysed in relation to historical sociotechnical concepts and methods that deal with infrastructure, programmatic uncertainty and environmental control. More specifically, current design approaches are studied against the background of early nineteenth-century urban interventions that aspired to curb impending epidemics and social crises in the emerging metropolis. In the second part of the paper, historical analysis is exchanged for a theoretical reflection about the relation between analysis – basically the measuring of the land (topography) – and project – or the organization and control of the terrain (territory). The article concludes with an active projection, in order to explore new perspectives for recent developments in urban design and call for a fundamental reappraisal of how our design attitudes and techniques should be integrated with the political and social context. © 2015, © The Author(s) 2015.

Kumar V.,University of Hohenheim | Sinha A.K.,University of Antwerp | Makkar H.P.S.,University of Hohenheim | Becker K.,University of Hohenheim
Food Chemistry | Year: 2010

Phytate is the primary storage form of both phosphate and inositol in plant seeds. It forms complexes with dietary minerals, especially iron and zinc, and causes mineral-related deficiency in humans. It also negatively impacts protein and lipid utilisation. It is of major concern for individuals who depend mainly on plant derivative foods. Processing techniques, such as soaking, germination, malting and fermentation, reduce phytate content by increasing activity of naturally present phytase. Supplementation of phytase in diets results in increase in mineral absorption. Apart from negative effects, its consumption provides protection against a variety of cancers mediated through antioxidation properties, interruption of cellular signal transduction, cell cycle inhibition and enhancement of natural killer (NK) cells activity. It has therapeutic use against diabetes mellitus, atherosclerosis and coronary heart disease and reduces kidney stone formation, HIV-1 and heavy metal toxicity; however, information on the dosage for humans for eliciting beneficial effects is limited. © 2009 Elsevier Ltd. All rights reserved.

Slabbekoorn H.,Leiden University | Bouton N.,University of Antwerp | van Opzeeland I.,Alfred Wegener Institute for Polar and Marine Research | Coers A.,Pelagic Regional Advisory Council | And 2 more authors.
Trends in Ecology and Evolution | Year: 2010

The underwater environment is filled with biotic and abiotic sounds, many of which can be important for the survival and reproduction of fish. Over the last century, human activities in and near the water have increasingly added artificial sounds to this environment. Very loud sounds of relatively short exposure, such as those produced during pile driving, can harm nearby fish. However, more moderate underwater noises of longer duration, such as those produced by vessels, could potentially impact much larger areas, and involve much larger numbers of fish. Here we call attention to the urgent need to study the role of sound in the lives of fish and to develop a better understanding of the ecological impact of anthropogenic noise. © 2010 Elsevier Ltd.

Lu G.,CAS Changchun Institute of Applied Chemistry | Lu G.,University of Massachusetts Amherst | Bu L.,University of Massachusetts Amherst | Li S.,CAS Changchun Institute of Applied Chemistry | And 2 more authors.
Advanced Materials | Year: 2014

Thermoelectric properties of conjugated polymers are found to improve upon homogeneously distributing conjugated polymer into an insulating supporting matrix. The local one-dimensional charge transport along the interpenetration conductive network simultaneously leads to lower thermal conductivity, higher electrical conductivity without sacrifice of Seebeck coefficient, and thus a higher figure of merit ZT, as compared with neat conjugated polymer. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Van de Voort F.,Leiden University | Schaye J.,Leiden University | Altay G.,Durham University | Theuns T.,Durham University | Theuns T.,University of Antwerp
Monthly Notices of the Royal Astronomical Society | Year: 2012

Simulations predict that galaxies grow primarily through the accretion of gas that has not gone through an accretion shock near the virial radius and that this cold gas flows towards the central galaxy along dense filaments and streams. There is, however, little observational evidence for the existence of these cold flows. We use a large, cosmological, hydrodynamical simulation that has been post-processed with radiative transfer to study the contribution of cold flows to the observed z= 3 column density distribution of neutral hydrogen, which our simulation reproduces. We find that nearly all of the Hi absorption arises in gas that has remained colder than 10 5.5K, at least while it was extragalactic. In addition, the majority of the Hi is falling rapidly towards a nearby galaxy, with non-negligible contributions from outflowing and static gas. Above a column density of cm -2, most of the absorbers reside inside haloes, but the interstellar medium only dominates for cm -2. Haloes with total mass below 10 10 M ⊙ dominate the absorption for cm -2, but the average halo mass increases sharply for higher column densities. Although very little of the Hi in absorbers with cm -2 resides inside galaxies, systems with cm -2 are closely related to star formation: most of their Hi either will become part of the interstellar medium before z= 2 or has been ejected from a galaxy at z > 3. Cold accretion flows are critical for the success of our simulation in reproducing the observed rate of incidence of damped Lyman-α and particularly that of Lyman limit systems. We therefore conclude that cold accretion flows exist and have already been detected in the form of high column density Hi absorbers. © 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS.

Novais S.C.,University of Aveiro | de Coen W.,University of Antwerp | Amorim M.J.B.,University of Aveiro
PLoS ONE | Year: 2012

Background: Molecular mechanisms of response to pesticides are scarce and information on such responses from soil invertebrates is almost inexistent. Enchytraeus albidus (Oligochaeta) is a standard soil ecotoxicology model species for which effects of many pesticides are known on survival, reproduction and avoidance behaviour. With the recent microarray development additional information can be retrieved on the molecular effects. Methodology/Principal Findings: Experiments were performed to investigate the transcription responses of E. albidus when exposed to three pesticides - dimethoate (insecticide), atrazine (herbicide) and carbendazim (fungicide) - in a range of concentrations that inhibited reproduction by 10%, 20%, 50% and 90% (EC10, EC20, EC50 and EC90, respectively). The goal of this study was to further identify key biological processes affected by each compound and if dose-related. All three pesticides significantly affected biological processes like translation, regulation of the cell cycle or general response to stress. Intracellular signalling and microtubule-based movement were affected by dimethoate and carbendazim whereas atrazine affected lipid and steroid metabolism (also by dimethoate) or carbohydrate metabolism (also by carbendazim). Response to DNA damage/DNA repair was exclusively affected by carbendazim. Conclusions: Changes in gene expression were significantly altered after 2 days of exposure in a dose-related manner. The mechanisms of response were comparable with the ones for mammals, suggesting across species conserved modes of action. The present results indicate the potential of using gene expression in risk assessment and the advantage as early markers. © 2012 Novais et al.

Most manipulation experiments simulating global change in tundra were short-term or did not measure plant growth directly. Here, we assessed the growth of three shrubs (Cassiope tetragona, Empetrum hermaphroditum and Betula nana) at a subarctic heath in Abisko (Northern Sweden) after 22 years of warming (passive greenhouses), fertilisation (nutrients addition) and shading (hessian fabric), and compare this to observations from the first decade of treatment. We assessed the growth rate of current-year leaves and apical stem (primary growth) and cambial growth (secondary growth), and integrated growth rates with morphological measurements and species coverage. Primary- and total growth of Cassiope and Empetrum were unaffected by manipulations, whereas growth was substantially reduced under fertilisation and shading (but not warming) for Betula. Overall, shrub height and length tended to increase under fertilisation and warming, whereas branching increased mostly in shaded Cassiope. Morphological changes were coupled to increased secondary growth under fertilisation. The species coverage showed a remarkable increase in graminoids in fertilised plots. Shrub response to fertilisation was positive in the short-term but changed over time, likely because of an increased competition with graminoids. More erected postures and large, canopies (requiring enhanced secondary growth for stem reinforcement) likely compensated for the increased light competition in Empetrum and Cassiope but did not avoid growth reduction in the shade intolerant Betula. The impact of warming and shading on shrub growth was more conservative. The lack of growth enhancement under warming suggests the absence of long-term acclimation for processes limiting biomass production. The lack of negative effects of shading on Cassiope was linked to morphological changes increasing the photosynthetic surface. Overall, tundra shrubs showed developmental plasticity over the longer term. However, such plasticity was associated clearly with growth rate trends only in fertilised plots.

Dhondt A.A.,Cornell University | Dhondt A.A.,French National Center for Scientific Research | Dhondt A.A.,University of Antwerp
Journal of Animal Ecology | Year: 2010

1. In studies on the effect of competition in plant communities two terms are used to describe its effects: the absolute reduction in growth of an individual as a consequence of the presence of another one is called intensity, while the relative impact of competition on an individual as a proportion of the impact of the whole environment is called importance. One school of thought is that the role of competition remains constant across productivity gradients, while the other is that it decreases with increasing severity. J.B. Grace (1991. A clarification of the debate between grime and tilman. Functional Ecology, 5, 583-587.) suggested that the apparent contradiction might be solved if we acknowledge that the two schools are discussing different aspects of competition: the intensity of competition might remain constant while its importance declines with increasing severity. 2. There are no studies that compare intensity and importance of competition in bird populations between areas that differ in quality or productivity and hence it is not possible to make predictions how intensity or importance of competition would vary between them. 3. I compared variation in intensity and importance of competition of three demographic variables between five plots that differ strongly in quality for great Parus major L. and blue tit Cyanistes caeruleus (L.). 4. Both intensity and importance of competition are larger in great than in blue tit populations meaning that the effect of competition on demographic variables is stronger in great than in blue tits and that the contribution of competition to variation in these variables is relatively higher in great than in blue tits. 5. Intensity of competition is higher in low quality than in high quality plots for both species, a result not expected from studies in plant communities. 6. Importance of competition varies strongly between plots. It is larger in oak-dominated plots than in mixed deciduous plots. 7. In birds breeding density increases with habitat quality but is limited by territorial behaviour. As a result competition for food is reduced in high quality habitats resulting in a reduction of competition intensity in high quality sites in which birds breed at high densities. 8. It can be predicted that in studies of territorial species density dependent effects on reproduction are more likely to be detected in low quality sites explaining in part differences in results between studies. © 2009 British Ecological Society.

Krstajic P.M.,University of Belgrade | Peeters F.M.,University of Antwerp
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

The many-body correction to the band structure of a quasi-free-standing graphene layer is obtained within the Overhauser approach, where the electron-plasmon interaction is described as a field theoretical problem. We find that the Dirac-like spectrum is shifted by ΔE(k=0), which is on the order of 50-150 meV, depending on the electron concentration n e, and is in semiquantitative agreement with experimental data. The value of the Fermi velocity is renormalized by several percents and decreases with increasing electron concentration as found experimentally. © 2012 American Physical Society.

Runhaar J.,Erasmus Medical Center | Koes B.W.,Erasmus Medical Center | Clockaerts S.,Erasmus Medical Center | Clockaerts S.,University of Antwerp | Bierma-Zeinstra S.M.A.,Erasmus Medical Center
Obesity Reviews | Year: 2011

Summary: Obesity has been identified as a risk factor for osteoarthritis. For the weight-bearing joints, the combination of increased load and changed joint biomechanics could be regarded as underlying principle for this relation. This systematic review of the literature focused on the differences between obese and normal-weight subjects in biomechanics of the hip, knee and ankle joint during every day movements to summarize differences in joint load due to both higher body weight and differences in movement patterns. A systematic search, up to November 2010, was performed in the Pubmed and Embase databases. This review showed that obese individuals adjust their movement strategy of every day movements. At self-selected speed, obese individuals walked slower, with shorter and wider steps, had longer stance duration and had a greater toe-out angle compared with normal-weight individuals. Obese sit-to-stand movement was characterized by less hip flexion and greater foot displacement. Obese individuals showed altered biomechanics during every day movements. These altered biomechanics could be related to the initiation of osteoarthritis by a change in the load-bearing regions of the articular cartilage in the weight-bearing joints. © 2011 The Authors. obesity reviews © 2011 International Association for the Study of Obesity.

Vandewoude M.,University of Antwerp | Van Gossum A.,Free University of Colombia
Journal of Nutrition, Health and Aging | Year: 2013

Objectives: To identify older subjects at risk of malnutrition using the most appropriate tool available for the specific setting and to evaluate the Mini Nutritional Assessment short form (MNA-SF) in a sample of nonagenarians. Design: Questionnaire based national screening week for the risk and prevalence of malnutrition in older people (NutriAction). Setting: Older people in the community (CD) and in nursing homes (NH). Participants: General practices (n=70) and Nursing Homes (n=70). Measurements: Questionnaire based on items from validated screening instruments: the MNA-SF, the Short Nutritional Assessment Questionnaire (SNAQ) and additional clinically relevant parameters (mobility, independence, social isolation and co-morbidities). Results: In total 5,334 people were screened of which 16% were aged over 90 years. In this age group, 66% of the screened individuals were at risk of malnutrition (MNA ≤ 11), and women were affected significantly more than men (p<0.001). Actual malnutrition was present in 22% (BMI <20), 20% (SNAQ) and 25% (clinical evaluation). The MNA appeared to be very sensitive but had a low specificity as well in the nonagenarians (98% and 44%) as in the younger old (97% and 52%). The SNAQ was not a sensitive tool for detecting malnutrition in this study population (25%). Although clinical impression had a low sensitivity (60-61%) it has a good specificity (86% in 90+ and 91% below 90yr). Conclusion: The overall risk of and the prevalence of malnutrition is common in older people. The prevalence is higher in women, in nursing homes and in older age groups. The MNA-SF followed by a clinical subjective evaluation seems to be the preferred strategy for detecting malnutrition in nonagenarians. © 2013 Serdi and Springer-Verlag France.

Verbruggen A.,University of Antwerp
Ecological Economics | Year: 2013

Reversibility and irreversibility are poorly defined in the decision-making literature. Defining reversibility as "the ability to maintain and to restore the functional performance of a system" is consistent with thermodynamics; specification of its crucial terms is case dependent. Reversibility is coming in degrees from flexibility, over rigidity to preclusion, with irreversibility as an absolute end. Further substantiating reversibility considers three variables: duration of impacts, revoking costs, and substitutability. Substitutability depends on weights assigned to the strict identity or to the functional performance of something valued. For given degrees of substitutability, revocability of an action is measurable in time-dependent revoking costs. Together with future time and doubt, reversibility sets a three-dimensional context for societal decision-making, revealing domes of expanding complexity. Cost-benefit analysis is a useful decision tool at lower complexity but falters at high complexity because there prevail non-monetary trade-offs. A revival and proper use of the concept reversibility are recommended for improved dialog on major societal issues, with climate change outstanding as the case where reversibility could turn into absolute irreversibility. Also shown is the correspondence between reversibility and ecological concepts like resilience, lock-in, tipping points, and others. © 2012 Elsevier B.V.

Tjalma W.A.A.,University of Antwerp | Depuydt C.E.,Sonic Healthcare Benelux
European Journal of Obstetrics Gynecology and Reproductive Biology | Year: 2013

Cervical cancer can and should be a historical disease. The reality, however, is that every year more than half a million women are diagnosed with cervical cancer and a quarter of a million die of this disease. The causal factor for cervical cancer is a persistent HPV infection and therefore a vaccine was developed: prophylactic HPV vaccination will reduce cervical cancer by 70%. Screening based on cytology will miss more than 40% of the abnormalities. The introduction of vaccination should lead to the reintroduction of cervical cancer screening based on HPV detection. Primary HPV screening followed by cytology will detect almost all abnormalities. Not all HPV tests, however, are the same! Clinicians are generally not aware that there is a huge difference among HPV tests. If a low grade lesion progresses to a high grade or invasive cancer, their HPV is likely to integrate. During integration L1 expression can be lost, but E6/E7 expression will always remain present. If the viral HPV is completely integrated then a L1 test looking for only L1 expression will miss this (pre)cancer, while the E6/E7 test will not miss it. HPV tests used in cervical cancer screening should be based on the early (E) and the late (L) genes in order not to miss the abnormality. © 2013 Elsevier Ireland Ltd. All rights reserved.

Aims: To give a review of some basic research recording and clinical evaluations of bladder afferent nerves and the sensory information related to them. Methods: Literature survey. Results: Direct investigation of the afferent nerve pathways of the lower urinary tract (LUT) can be done in animal studies where potentials can be recorded and measured directly in the dorsal roots after laminectomy. Differentiation between A delta and C fibers is possible when conduction speed is determined. In humans afferent innervation can be studied clinically with determination of the sensation on sensation-related bladder diary, during cystometrical bladder filling, with local electrical stimulation. All need further study. Electrodiagnostic tests are further explored. Conclusions: Both basic research and clinical evaluation of afferent nerves and sensory function in the LUT are possible. To find out how both relate to each other, and how this function can be evaluated, is the task to be done now. © 2009 Wiley-Liss, Inc.

Verbraecken J.,University of Antwerp
Breathe | Year: 2013

Complex sleep apnoea syndrome (CompSAS) is a type of central apnoea characterised by the development or persistence of central apnoeas or hypopnoeas during application of continuous positive airway pressure (CPAP; central apnoea index ≥5 events·h-1). These patients present with predominantly obstructive apnoeas during diagnostic sleep studies. No clinical characteristics have been identified which can distinguish them from patients with a normal response during CPAP titration. Probably, this pattern is provoked by the application of high CPAP pressures in obstructive sleep apnoea syndrome patients with enhanced chemoreceptor sensitivity, or in patients with pronounced sleep fragmentation. Negative feedback is sent to the respiratory centre, via the Hering-Breuer reflex, which can lead to central apnoea. However, these explanations remain hypothetical at present. In a broader perspective, any occurrence of significant central apnoea activity during attempts to restore airway patency could be classified as CompSAS. Treatment modalities consist of prevention on the one hand (avoidance of high pressures and permissive flow limitation), and advanced ventilation techniques (adaptive servo ventilation) on the other hand.

Tatti N.,University of Antwerp
Proceedings of the ACM SIGKDD International Conference on Knowledge Discovery and Data Mining | Year: 2010

One of the main current challenges in itemset mining is to discover a small set of high-quality itemsets. In this paper we propose a new and general approach for measuring the quality of itemsets. The method is solidly founded in Bayesian statistics and decreases monotonically, allowing for efficient discovery of all interesting itemsets. The measure is defined by connecting statistical models and collections of itemsets. This allows us to score individual itemsets with the probability of them occuring in random models built on the data. As a concrete example of this framework we use exponential models. This class of models possesses many desirable properties. Most importantly, Occam's razor in Bayesian model selection provides a defence for the pattern explosion. As general exponential models are infeasible in practice, we use decomposable models; a large sub-class for which the measure is solvable. For the actual computation of the score we sample models from the posterior distribution using an MCMC approach. Experimentation on our method demonstrates the measure works in practice and results in interpretable and insightful itemsets for both synthetic and real-world data. © 2010 ACM.

Verdoolaege G.,Ghent University | Scheunders P.,University of Antwerp
Journal of Mathematical Imaging and Vision | Year: 2012

This paper concerns the geometry of the zero-mean multivariate generalized Gaussian distribution (MGGD) and the calculation of geodesic distances on the MGGD manifold. The MGGD is a suitable distribution for the modeling of multivariate (color, multispectral, vector and tensor images, etc.) image wavelet statistics. Expressions are derived for the Fisher-Rao metric for the zero-mean MGGD model. A closed-form expression is obtained for the geodesic distance on the submanifolds characterized by a fixed MGGD shape parameter. Suitable approximate solutions to the geodesic equations are presented in the case of MGGDs with varying shape parameters. An application to image texture similarity measurement in the wavelet domain is briefly discussed, comparing the performance of the geodesic distance and the Kullback-Leibler divergence. © 2011 Springer Science+Business Media, LLC.

Van geertruyden J.-P.,University of Antwerp
Clinical Microbiology and Infection | Year: 2014

Possible pathophysiological, clinical and epidemiological interactions between human immunodeficiency virus (HIV) and tropical pathogens, especially malaria parasites, constitute a concern in tropical areas. Two decades of research have shown that HIV-related immunosuppression is correlated with increased malaria infection, burden, and treatment failure, and with complicated malaria, irrespective of immune status. The recent role out of antiretroviral therapies and new antimalarials, such as artemisinin combination therapies, raise additional concerns regarding possible synergistic and antagonistic effects on efficacy and toxicity. Co-trimoxazole, which is used to prevent opportunistic infections, has been shown to have strong antimalarial prophylactic properties, despite its long-term use and increasing antifolate resistance. The administration of efavirenz, a non-nucleoside reverse transcriptase inhibitor, with amodiaquine-artesunate has been associated with increased toxicity. Recent in vivo observations have confirmed that protease inhibitors have strong antimalarial properties. Ritonavir-boosted lopinavir and artemether-lumefantrine have a synergistic effect in terms of improved malaria treatment outcomes, with no apparent increase in the risk of toxicity. Overall, for the prevention and treatment of malaria in HIV-infected populations, the current standard of care is similar to that in non-HIV-infected populations. The available data show that the wider use of insecticide-treated bed-nets, co-trimoxazole prophylaxis and antiretroviral therapy might substantially reduce the morbidity of malaria in HIV-infected patients. These observations show that those accessing care for HIV infection are now, paradoxically, well protected from malaria. These findings therefore highlight the need for confirmatory diagnosis of malaria in HIV-infected individuals receiving these interventions, and the provision of different artemisinin-based combination therapies to treat malaria only when the diagnosis is confirmed. © 2014 The Authors.

This exploratory study focuses on interactions containing jocular FTAs in Australian English in relation to cultural attitudes that are valued in an Anglo-Australian cultural context. 'Not taking yourself too seriously' is considered a preference in the English-speaking world, but what seems to make it even more prominent in Australia is not its humorous potential, but rather a strong link with 'mateship', i.e. projecting equality. The results of this study show not only a difference between public and personal offence taken at FTAs, but also a clear connection that can be observed between the category of 'mateship' and public offence. Furthermore, a distinction between laughter (an omnipresent reaction in the analysed data), funniness and 'mateship' in relation to public offence is made. The findings are based on interactions from the television gameshow Big Brother Australia 2012. © 2013 Elsevier B.V.

Vanacker P.,University of Antwerp
European Journal of Emergency Medicine | Year: 2016

BACKGROUND: Endovascular treatment for acute ischemic stroke with a large intracranial occlusion was recently shown to be effective. Timely knowledge of the presence, site, and extent of arterial occlusions in the ischemic territory has the potential to influence patient selection for endovascular treatment. We aimed to find predictors of large vessel occlusive strokes, on the basis of available demographic, clinical, radiological, and laboratory data in the emergency setting. METHODS: Patients enrolled in ASTRAL registry with acute ischemic stroke and computed tomography (CT)-angiography within 12 h of stroke onset were selected and categorized according to occlusion site. Easily accessible variables were used in a multivariate analysis. RESULTS: Of 1645 patients enrolled, a significant proportion (46.2%) had a large vessel occlusion in the ischemic territory. The main clinical predictors of any arterial occlusion were in-hospital stroke [odd ratios (OR) 2.1, 95% confidence interval 1.4–3.1], higher initial National Institute of Health Stroke Scale (OR 1.1, 1.1–1.2), presence of visual field defects (OR 1.9, 1.3–2.6), dysarthria (OR 1.4, 1.0–1.9), or hemineglect (OR 2.0, 1.4–2.8) at admission and atrial fibrillation (OR 1.7, 1.2–2.3). Further, the following radiological predictors were identified: time-to-imaging (OR 0.9, 0.9–1.0), early ischemic changes (OR 2.3, 1.7–3.2), and silent lesions on CT (OR 0.7, 0.5–1.0). The area under curve for this analysis was 0.85. Looking at different occlusion sites, National Institute of Health Stroke Scale and early ischemic changes on CT were independent predictors in all subgroups. CONCLUSION: Neurological deficits, stroke risk factors, and CT findings accurately identify acute ischemic stroke patients at risk of symptomatic vessel occlusion. Predicting the presence of these occlusions may impact emergency stroke care in regions with limited access to noninvasive vascular imaging. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.

Lam J.S.L.,Nanyang Technological University | Lam J.S.L.,University of Antwerp
Journal of Transport Geography | Year: 2011

This paper offers a tool for analysing patterns of maritime supply chains. The study uses empirical data on slot capacity deployed by container shipping lines for analysing ports (as nodes) and routes and shipping lines (as links) that are embedded within the maritime supply chain. The ports of Singapore and Hong Kong are chosen to illustrate the respective transhipment and gateway perspectives. Findings reveal that geographical location and changes in the constitution of players can have reverberations on the maritime supply chain dynamics that traverse the port. Furthermore, evidence from trade route data also shows that maritime supply chain dynamics associated with transhipment and gateway ports could be governed by different levels of scope economies, demand complementarity and market power. The paper illustrates the abundant potential of slot capacity analysis for academic and industry/market research. Thus, future research can be pursued in various contexts and for different applications. © 2010 Elsevier Ltd.

Megnigbeto E.,Bureau dEtudes et de Recherches en Science de linformation BERSI | Megnigbeto E.,University of Antwerp
Scientometrics | Year: 2013

Bibliographic data of publications indexed in Web of Science with at least one (co-)author affiliated to any of the 15 West African countries and published from 2001 to 2010 included are downloaded. Analyses focused one collaboration indicators especially intra regional collaboration, intra African collaboration and collaboration with the world. Results showed that the rate of papers with only one author is diminishing whereas the rate of papers with six and more authors is increasing. Nigeria is responsible for more than half the region's total scientific output. The main African partner countries are South Africa (in the Southern Africa, Cameroon (in the Central Africa), Kenya and Tanzania (in the Eastern Africa). The main non African partner countries are France, USA and United Kingdom, which on their own contributed to over 63 % of the papers with a non West African address. Individual countries have higher international collaboration rate, except Nigeria. West African countries cooperated less with each other and less with African and developing countries than they did with developed ones. The study suggests national authorities to express in actions their commitment to allot at least 1 % of their GDP to science and technology funding. It also suggests regional integration institutions to encourage and fund research activities that involve several institutions from different West African countries in order to increase intra regional scientific cooperation. © 2013 Akadémiai Kiadó, Budapest, Hungary.

Brouns I.,University of Antwerp
Advances in anatomy, embryology, and cell biology | Year: 2012

Afferent nerves in the airways and lungs contribute to optimisation of the breathing pattern, by providing local pulmonary information to the central nervous system. Airway sensory nerve terminals are consequently tailored to detect changes readily in the physical and chemical environment, thereby leading to a variety of respiratory sensations and reflex responses. Most intrapulmonary nerve terminals arise from fibres travelling in the vagal nerve, allowing a classification of "sensory airway receptors", based on their electrophysiologically registered action potential characteristics. Nowadays, at least six subtypes of electrophysiologically characterised vagal sensory airway receptors have been described, including the classical slowly and rapidly adapting (stretch) receptors and C-fibre receptors. The architecture of airways and lungs makes it, however, almost impossible to locate functionally the exact nerve terminals that are responsible for transduction of a particular intrapulmonary stimulus. With the advances in immunohistochemistry in combination with confocal microscopy, airway sensory receptor end organs can now be examined and evaluated objectively. Based on their "neurochemical coding", morphology, location and origin, three sensory receptor end organs are currently morphologically well characterised: smooth muscle-associated airway receptors (SMARs), neuroepithelial bodies (NEBs) and visceral pleura receptors (VPRs). The present information on the functional, morphological and neurochemical characteristics of these sensory receptors leads to important conclusions about their (possible) function. Currently, ex vivo lung models are developed that allow the selective visualisation of SMARs, NEBs and VPRs by vital staining. The described ex vivo models will certainly facilitate direct physiological studies of the morphologically and neurochemically identified airway receptors, thereby linking morphology to physiology by identifying in situ functional properties of a given receptor end organ.

Mortelmans T.,University of Antwerp
Journal of Pragmatics | Year: 2012

This paper investigates the uses of epistemic must and its Dutch and German cognates moeten and müssen. Starting point is the observation that epistemic must occurs remarkably more often in English than its immediate counterparts in the two other languages. By means of a detailed comparison on the basis of a self-compiled English-Dutch-German translation corpus of fictional texts, this paper identifies the factors determining these frequency differences. First, it appears that English must covers a wider inferential ground than its Dutch and German counterparts, as it can also code highly subjective 'conjectural' inferences apart from the typical must-inferences based on observable evidence and general knowledge. Second, epistemic must is often used to appeal to the addressee, to invoke the addressee's sympathy among other things. Such intersubjective uses of epistemic must seem to be rare with the German and Dutch cognates. Third, general communicative preferences in English promote the use of hedging devices (like epistemic modal verbs), as they contribute to an indirect and addressee-oriented way of interaction that is more valued in English than in German. © 2012 Elsevier B.V.

De Knop K.J.,University of Antwerp
Advances in clinical chemistry | Year: 2010

Diagnosis of IgE-mediated allergies is not always straightforward, as traditional tests can yield equivocal or negative results and provocation tests are hampered by several practical and ethical limitations. During the last decades two new in vitro techniques have entered the field of allergy diagnosis, that is, flow-assisted analysis of allergen-specific activated basophils and component-resolved diagnosis (CRD). This review focuses on component-resolved allergy diagnosis by microarray that has evolved from recent advances in molecular allergology and biochip technology. The technique allows a comprehensive analysis of individual sensitization profiles with multiplexed purified and recombinant allergens within a single run using only a minute amount of serum, providing information that largely exceeds the output from current sIgE capturing tools. Actually, multiplexing allows identification of diagnostic patterns that may facilitate the formulation of diagnostic algorithms. Although CRD by microarray sounds promising, the diagnostic performance requires further intensive assessment before it can enter mainstream application. In our opinion, the technique should currently be considered a complementary diagnostic tool rather than a first-line choice.

Peeraer J.,Flemish Association for Development Cooperation and Technical Assistance | Van Petegem P.,University of Antwerp
Computers and Education | Year: 2012

This research describes the development and validation of an instrument to measure integration of Information and Communication Technology (ICT) in education. After literature research on definitions of integration of ICT in education, a comparison is made between the classical test theory and the item response modeling approach for the development and validation of a questionnaire. Following the last approach, a construct on integration of ICT is developed, items are generated and an outcome space of Likert type answering categories is defined. The resulting questionnaire has been administered to 933 teacher educators. In this study the collected data are tested for fit to the Rasch model of measurement. It is concluded that the instrument can be used for fundamental measurement of perceived use of ICT for teaching and support of student learning of the reference population, allowing for identification of stages of innovation of ICT integration. We reflect on the critical value of the item response modeling approach and the Rasch measurement model for measurement of integration of ICT in education and discuss some limitations of the study. © 2012 Elsevier Ltd. All rights reserved.

Buyle M.,Artesis University College of Antwerp | Braet J.,University of Antwerp | Audenaert A.,Artesis University College of Antwerp
Renewable and Sustainable Energy Reviews | Year: 2013

The last decades, lowering the ecological impact of buildings is receiving increased attention by researchers, policy-makers and companies. Mostly the focus is on reducing energy consumption and the use of eco-friendly materials, but the concept of life-cycle thinking is growing in importance. This paper tries to give an overview of the current situation of Life cycle assessment (LCA) in the construction industry, both of regulatory developments and academic case studies. After a short history of LCA, the focus is on LCA methodology, new standards and frameworks and an extensive selection of recent case studies. Despite some inherent limitations of LCA as an analytic tool and fundamental differences between the individual cases, still some common trends can be indicated. In standard buildings, the use phase contributes up to 90% of the total environmental burdens, mainly due to heating and/or cooling. Due to regulations, new buildings become more energy efficient, and thereby other phases of the life cycle gain in importance e.g., choice of materials, construction, end-of-life and water use. These research topics deserve more attention, together with economic issues, the improvement of data quality and implementation of probability density distributions. © 2013 Elsevier Ltd.

Claes K.J.,University Hospitals Leuven | Viaene L.,University Hospitals Leuven | Heye S.,University Hospitals Leuven | Meijers B.,University Hospitals Leuven | And 2 more authors.
Journal of Clinical Endocrinology and Metabolism | Year: 2013

Context: Sclerostin, a Wnt antagonist produced by osteocytes, regulates osteoblast activity and is a well-established key player inboneturnover. Recent data indicate that theWntpathwaymayalso be involved in vascular calcification. Objective: The present study tests the hypothesis that serum sclerostin levels are associated with vascular calcification in patients with chronic kidney disease (CKD) not yet receiving dialysis. Design, Setting, Participants, and Measurements: We performed a cross-sectional analysis in 154 patients with CKD. Aortic calcification (AC) was assessed by lumbar X-ray and scored with a maximum score of 24. In addition to traditional and nontraditional cardiovascular (CV) risk factors, serum sclerostin levels were assessed (ELISA). Regression analysis was performed to identify determinants of serum sclerostin and AC. Results: AC was present in 59% of patients. Older age (P < .0001), male sex (P = .006), lower estimated glomerular rate (eGFR) (P = .0008), lower bone-specific alkaline phosphatase (P = .03), and the absence of AC (P = .006) were identified as independent determinants of higher serum sclerostin levels. In univariate logistic regression, higher age, diabetes,CVhistory, higher body mass index, higher serum C-reactive protein and sclerostin levels and lower estimated glomerular rate were all associated with the presence of AC. In multivariate analysis, lower, not higher, sclerostin levels (P = .04, odds ratio [OR] per ng/mL of 0.24), higher age (P < .0001, OR per year of 1.17) and CV history (P = .02, OR for a positive CV history of 3.83) were identified as independent determinants of AC. Conclusions: In this cohort of patients with CKD, we found that patients with aortic calcifications (ACs) had higher sclerostin levels. However, in multivariate analysis, the association became inverse. Additional clinical and experimental studies are urgently required to clarify whether or not sclerostin protects against progression of vascular calcification. Copyright © 2013 by The Endocrine Society.

Neek-Amal M.,University of Tehran | Peeters F.M.,University of Antwerp
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

Atomistic simulations are used to study the bending of rectangular graphene nanoribbons subjected to axial stress both for free boundary and supported boundary conditions. The shapes of the deformations of the buckled graphene nanoribbons, for small values of the stress, are sine waves where the number of nodal lines depend on the longitudinal size of the system and the applied boundary condition. The buckling strain for the supported boundary condition is found to be independent of the longitudinal size and estimated to be 0.86%. From a calculation of the free energy at finite temperature we find that the equilibrium projected two-dimensional area of the graphene nanoribbon is less than the area of a flat sheet. At the optimum length the boundary strain for the supported boundary condition is 0.48%. © 2010 The American Physical Society.

Neek-Amal M.,University of Tehran | Peeters F.M.,University of Antwerp
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

Nanoindentation of bilayer graphene is studied using molecular-dynamics simulations. We compared our simulation results with those from elasticity theory as based on the nonlinear Föppl-Hencky equations with rigid boundary condition. The force-deflection values of bilayer graphene are compared to those of monolayer graphene. Young's modulus of bilayer graphene is estimated to be 0.8 TPa which is close to the value for graphite. Moreover, an almost flat bilayer membrane at low temperature under central load has a 14% smaller Young's modulus as compared to the one at room temperature. © 2010 The American Physical Society.

Grasner J.-T.,University of Kiel | Bossaert L.,University of Antwerp | Bossaert L.,Universiteitsplein 1
Best Practice and Research: Clinical Anaesthesiology | Year: 2013

Major European institutions report cardiovascular disease (CVD) as the first cause of death in adults, with cardiac arrest and sudden death due to coronary ischaemia as the primary single cause. Global incidence of CVD is decreasing in most European countries, due to prevention, lifestyle and treatment. Mortality of acute coronary events inside the hospital decreases more rapidly than outside the hospital. To improve the mortality of cardiac arrest outside the hospital, reliable epidemiological and process figures are essential: "we can only manage what we can measure". Europe is a patchwork of 47 countries (total population of 830 million), with a 10-fold difference in incidence of coronary heart disease between North and South, East and West, and a 5-fold difference in number of EMS-treated cardiac arrest (range 17-53/1000,000/year). Epidemiology of cardiac arrest should not be calculated as a European average, but it is appropriate to describe the incidence of cardiac arrest, the resuscitation process, and the outcome in each of the European regions, for benchmarking and quality management. Epidemiological reports of cardiac arrest should specify definitions, nominator (number of cases) and denominator (study population). Recently some regional registries in North America, Japan and Europe fulfilled these conditions. The European Registry of Cardiac Arrest (EuReCa) has the potential to achieve these objectives on a pan-European scale. For operational applications, the Utstein definition of "Cardiac arrest" is used which includes the potential of survival. For application in community health, the WHO definition of "sudden death" is frequently used, describing the mode of death. There is considerable overlap between both definitions. But this explains that no single method can provide all information. Integrating data from multiple sources (local, national, multinational registries and surveys, death certificates, post-mortem reports, community statistics, medical records) may create a holistic picture of cardiac arrest in the community. © 2013 Elsevier Ltd. All rights reserved.

Macharia H.,University of Antwerp | Goos P.,Erasmus University Rotterdam
Journal of Quality Technology | Year: 2010

Industrial experiments often involve factors that are hard to change or costly to manipulate and thus make it undesirable to use a complete randomization. In such cases, the split-plot design structure is a cost-efficient alternative that reduces the number of independent settings of the hard-to-change factors. In general, model estimation for split-plot designs requires the use of generalized least squares (GLS). However, for some split-plot designs (including not only classical agricultural split-plot designs, but also some secondorder split-plot response surface designs), ordinary least squares (OLS) estimates are equivalent to GLS estimates. These designs are called equivalent-estimation designs and offer the advantage that estimation of the factor effects does not require estimation of the variance components in the split-plot model. As an alternative to these equivalent-estimation designs, one can use D-optimal designs that guarantee efficient estimation of the fixed effects of the statistical model that is appropriate given the split-plot structure. We explore the relationship between equivalent-estimation and D-optimal split-plot designs for a second-order response surface model and propose an algorithm for generating D-efficient equivalent-estimation split-plot designs. This approach allows for a flexible choice of the number of hard-to-change factors, the number of easy-to-change factors, the number of whole plots, and the total sample size.

Engelborghs S.,University of Antwerp
Revue Neurologique | Year: 2013

The cerebrospinal fluid (CSF) biomarkers β-amyloid1-42 (Aβ1-42), total tau protein (T-tau) and hyperphosphorylated tau (P-tau181P) are well-validated and are increasingly used in clinical practice as an affirmative diagnostic tool for Alzheimer's disease (AD). These biomarkers have also been implemented in the revised diagnostic criteria of AD. The combination of the CSF biomarkers Aβ1-42, T-tau and P-tau181P results in high levels of sensitivity, specificity and diagnostic accuracy for discriminating AD from controls (including psychiatric disorders like depression). These biomarkers can be applied for diagnosing AD in the prodromal phase of the disease (mild cognitive impairment). In case of doubt between vascular dementia (VaD) or mixed AD-VaD pathology in dementia patients, the determination of CSF Aβ1-42, T-tau and P-tau 181P levels is of help to confirm or exclude the AD component in the pathophysiology of the dementia syndrome. However, their discriminatory power for the differential diagnosis of dementia is suboptimal. Other CSF biomarkers like Aβ1-40, and those that are reflective of the pathology of non-AD dementias, could improve the accuracy of differential dementia diagnosis. The added differential diagnostic value of the CSF biomarkers Aβ1-42, T-tau and P-tau181P could lie within those cases in which the routine clinical diagnostic work-up is not able to discriminate between AD or non-AD dementias. In summary, the CSF biomarkers Aβ1-42, T-tau and P-tau181P can be used in clinical practice to discriminate AD from healthy aging (including psychiatric disorders like depression), to diagnose AD in its prodromal phase or in atypical forms with prominent non-memory impairment, to identify AD in patients with mixed pathologies and in case of an ambiguous (AD versus non-AD) dementia diagnosis. © 2013 Elsevier Masson SAS.

Zakaria N.,University of Antwerp
PloS one | Year: 2012

Corneal neovascularization results from the encroachment of blood vessels from the surrounding conjunctiva onto the normally avascular cornea. The aim of this study is to identify factors in human tears that are involved in development and/or maintenance of corneal neovascularization in humans. This could allow development of diagnostic tools for monitoring corneal neovascularization and combination monoclonal antibody therapies for its treatment. In an observational case-control study we enrolled a total of 12 patients with corneal neovascularization and 10 healthy volunteers. Basal tears along with reflex tears from the inferior fornix, superior fornix and using a corneal bath were collected along with blood serum samples. From all patients, ocular surface photographs were taken. Concentrations of the pro-angiogenic cytokines interleukin (IL)-6, IL-8, Vascular Endothelial Growth Factor (VEGF), Monocyte Chemoattractant Protein 1 (MCP-1) and Fas Ligand (FasL) were determined in blood and tear samples using a flow cytometric multiplex assay. Our results show that the concentration of pro-angiogenic cytokines in human tears are significantly higher compared to their concentrations in serum, with highest levels found in basal tears. Interestingly, we could detect a significantly higher concentration of IL- 6, IL-8 and VEGF in localized corneal tears of patients with neovascularized corneas when compared to the control group. This is the first study of its kind demonstrating a significant difference of defined factors in tears from patients with neovascularized corneas as compared to healthy controls. These results provide the basis for future research using animal models to further substantiate the role of these cytokines in the establishment and maintenance of corneal neovascularization.

Birder L.,University of Pittsburgh | Wyndaele J.-J.,University of Antwerp
Acta Physiologica | Year: 2013

The mechanisms underlying bladder sensation and the way we experience sensations during normal voiding and in pathology is complex and not well understood. During storage and emptying, mechanical changes occurring in number of cell types within the bladder wall (i.e. the uroepithelium and bladder afferents) can have a major influence on our sensory systems. In this review, we discuss bladder sensation with a focus on coding events in the periphery. © 2012 The Authors Acta Physiologica © 2012 Scandinavian Physiological Society.

Guns R.,University of Antwerp
Journal of Documentation | Year: 2013

Purpose: The aim of this paper is to propose a conceptual model of the field of informetrics. Specifically, the paper argues that informetrics comprises the study of entities in three dimensions: the social, documentary and epistemic dimensions containing respectively agents, documents, and concepts or cognitions. Design/methodology/approach: The paper outlines a conceptual model, drawing on earlier work by Kochen, Leydesdorff, Borgman and others. Subsequently, each dimension and interdimensional relation is analyzed and discussed. Findings: It is shown that not every study necessarily involves each of the three dimensions, but that the field as a whole cannot be reduced to one or two of them. Moreover, the dimensions should be kept separate but they are not completely independent. The paper discusses what kinds of relations exist between the dimensions. Special attention is given to the nature of the citation relation within this framework. The paper also considers the place of concepts like mapping, proximity and influence in the model. Research limitations/implications: This conceptual paper is a first step. Multi-relational networks may be a key instrument to further the study of the interplay between the three dimensions. Originality/value: The paper provides a framework to characterise informetric studies and makes the characteristics of the field explicit. © Emerald Group Publishing Limited.

Teixeira R.F.M.,University of Antwerp
Chemical Engineering Transactions | Year: 2014

The importance of Life Cycle Assessment (LCA) as an impact assessment tool has been growing in recent years. There are important mandates in place that provide incentives for companies to use this method to quantify the environmental impacts of their activities, and more are expected to follow. There are, however, some significant challenges that must still be addressed before the method becomes established practice. One of the most important barriers remaining is finding a widely accepted and accurate impact assessment method for biodiversity. This review article presents a reflection on the concept of species richness as it is currently used in Life Cycle Impact Assessment methodologies. It applies to calculations of biodiversity impacts from land use exclusively. Power law models such as the Species-Area Relationship are useful macroecological tools to predict potential extinctions from land use due to their apparent simplicity and broad applicability. The main assumptions of the SAR models are laid out and their limitations critically assessed when used in the context of LCA. Alternatives models are proposed for future evaluation by Industrial Ecologists and Biologists. The article also proposes a rationale under which a model can be considered to fit LCA's purpose, and finally conclude with a shortlist of topics for future research. Copyright © 2014, AIDIC Servizi S.r.l.

Kerckhove K.V.,Hasselt University | Hens N.,Hasselt University | Hens N.,University of Antwerp | Edmunds W.J.,London School of Hygiene and Tropical Medicine | Eames K.T.D.,London School of Hygiene and Tropical Medicine
American Journal of Epidemiology | Year: 2013

We expect social networks to change as a result of illness, but social contact data are generally collected from healthy persons. Here we quantified the impact of influenza-like illness on social mixing patterns.We analyzed the contact patterns of persons from England measured when they were symptomatic with influenza-like illness during the 2009 A/H1N1pdm influenza epidemic (2009-2010) and again 2 weeks later when they had recovered. Illness was associated with a reduction in the number of social contacts, particularly in settings outside the home, reducing the reproduction number to about one-quarter of the value it would otherwise have taken. We also observed a change in the age distribution of contacts. By comparing the expected age distribution of cases resulting from transmission by (a)symptomatic persons with incidence data, we estimated the contribution of both groups to transmission. Using this, we calculated the fraction of transmission resulting from (a)symptomatic persons, assuming equal duration of infectiousness. We estimated that 66% of transmission was attributable to persons with symptomatic disease (95% confidence interval: 0.23, 1.00). This has important implications for control: Treating symptomatic persons with antiviral agents or encouraging home isolation would be expected to have a major impact on transmission, particularly since the reproduction number for this strain was low. © 2013 The Author. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved.

Dixon E.,University of Oxford | Hadermann J.,University of Antwerp | Ramos S.,Diamond Light Source | Goodwin A.L.,University of Oxford | Hayward M.A.,University of Oxford
Journal of the American Chemical Society | Year: 2011

Reduction of La1-xCaxMnO3 (0.6 ≤ x ≤ 1) perovskite phases with sodium hydride yields materials of composition La1-xCaxMnO2+δ. The calcium-rich phases (x = 0.9, 1) adopt (La0.9Ca0.1)0.5Mn 0.5O disordered rocksalt structures. However local structure analysis using reverse Monte Carlo refinement of models against pair distribution functions obtained from neutron total scattering data reveals lanthanum-rich La1-xCaxMnO2+δ (x = 0.6, 0.67, 0.7) phases adopt disordered structures consisting of an intergrowth of sheets of MnO6 octahedra and sheets of MnO4 tetrahedra. X-ray absorption data confirm the presence of Mn(I) centers in La1-xCa xMnO2+δ phases with x < 1. Low-temperature neutron diffraction data reveal La1-xCaxMnO 2+δ (x = 0.6, 0.67, 0.7) phases become antiferromagnetically ordered at low temperature. © 2011 American Chemical Society.

Efimov K.,Leibniz University of Hanover | Xu Q.,Technical University of Delft | Xu Q.,University of Antwerp | Feldhoff A.,Leibniz University of Hanover
Chemistry of Materials | Year: 2010

The cubic perovskite Ba0.5Sr0.5Co 0.8Fe0.2O3-δ (denoted BSCF) is the state-of-the-art ceramic membrane material used for oxygen separation technologies above 1150 K. BSCF is a mixed oxygen-ion and electron conductor (MIEC) and exhibits one of the highest oxygen permeabilities reported so far for dense oxides. Additionally, it has excellent phase stability above 1150 K. In the intermediate temperature range (750-1100 K), however, BSCF suffers from a slow decomposition of the cubic perovskite into variants with hexagonal stacking that are barriers to oxygen transport. To elucidate details of the decomposition process, both sintered BSCF ceramic and powder were annealed for 180-240 h in ambient air at temperatures below 1123 K and analyzed by different transmission electron microscopy techniques. Aside from hexagonal perovskite Ba0.6Sr0.4CoO3-δ, the formation of lamellar noncubic phases was observed in the quenched samples. The structure of the lamellae with the previously unknown composition Ba1-xSr xCo2-yFeyO5-δ was found to be related to the 15R hexagonal perovskite polytype. The valence and spin-state transition of cobalt leading to a considerable diminution of its ionic radius can be considered a reason for BSCF's inherent phase instability at intermediate temperatures. © 2010 American Chemical Society.

Keune H.,Research Institute for Nature and Forest INBO | Keune H.,University of Antwerp
Environmental Health: A Global Access Science Source | Year: 2012

The magic word complexity has been buzzing around in science, policy and society for quite some time now. There seems to be a common feel for a new way of doing things, for overcoming the limits of tradition. From the combined perspective of critical complexity thinking and environment and health practice we want to contribute to the development of alternative routines that may help overcome the limitations of traditional environment and health science. On the one hand traditional environment and health science is too self-confident with respect to potential scientific insight in environment and health problems: complexity condemns us to limited and ambiguous knowledge and the need for simplification. A more modest attitude would be more realistic from that point of view. On the other hand from a problem solving perspective more boldness is required. Waiting for Godot (perfect undisputed knowledge) will not help us with respect to the challenges posed to society by environment and health problems. A sense of urgency is legitimate: the paralysis by traditional analysis should be resolved. Nevertheless this sense of urgency should not withhold us from investing in the problem solving quality of our endeavour; quality takes time, fastness from a quality perspective often leads us to a standstill. We propose the concept of critical complexification of environment and health practice that will enable the integration of relevant actors and factors in a pragmatic manner. We will illustrate this with practical examples and especially draw attention to the practical complexities involved, confronting us not only with fundamental questions, but also with fundamental challenges. © 2012 Keune; licensee BioMed Central Ltd.

Veenstra A.,Erasmus University Rotterdam | Notteboom T.,University of Antwerp
Journal of Transport Geography | Year: 2011

This paper sheds an empirical light on port development patterns by discussing the structure and the development of the Yangtze River ports system. We argue that the Yangtze River system is going through a regionalization phase, mainly in relation to the port of Shanghai. This process started on the lower Yangtze but is now also moving upstream. The transition towards the port regionalization phase is typically a gradual and market-driven process that mirrors the increased focus of market players on logistics integration. This paper builds on the existing literature on port systems and adapts port development models to river ports. Furthermore, we employ some statistical techniques that are common to the analysis of port systems, and introduce some techniques that have not been used much by transport geographers in ports. This paper will address the dynamics in the Yangtze River ports system by analyzing the level of cargo concentration and the degree of inequality in operations of the container ports. The paper also assesses observed differences in development of ports in different areas along the river (upstream/downstream) and reflects on the role of ownership structures in shaping regional load centre networks. © 2010 Elsevier Ltd.

Latre S.,University of Antwerp | Famaey J.,Ghent University | De Turck F.,Ghent University | Demeester P.,Ghent University
IEEE Communications Magazine | Year: 2014

The Internet was originally designed as a best effort packet forwarding substrate. However, since its inception, its purpose has shifted toward a rich service-centric delivery platform. Its underlying infrastructure as well as the number of connected devices have taken on immense proportions, and sharing of capabilities has come into widespread use. Moreover, the Internet's services are becoming increasingly interactive, context-aware, and content-oriented. This has led to stringent delivery requirements being imposed on the underlying infrastructure. Despite these evolutions, management of the Internet has not evolved significantly. It remains largely static and is unable to provide dynamic end-to-end service delivery guarantees in a costeffective manner. In this article, we propose the Fluid Internet, a novel paradigm aimed at tackling these management challenges. The Fluid Internet seamlessly provisions virtualized infrastructure capabilities, adapting the delivery substrate to the dynamic requirements of services and users, much like a fluid adapting to fit its surroundings. As such, the Fluid Internet gives a service provider the ability to manage its services end to end and elastically. Our vision is achieved through a unification of concepts from network virtualization, cloud computing, and service-centric networking. The relevant stakeholders, as well as their functions and interactions, are described. Additionally, we identify the major technical challenges that remain to be tackled for the Fluid Internet vision to become a reality. © 1979-2012 IEEE.

Robles H.,University of Antwerp | Robles H.,University of La Coruna | Ciudad C.,University of Leon
Conservation Biology | Year: 2012

Despite extensive research on the effects of habitat fragmentation, the ecological mechanisms underlying colonization and extinction processes are poorly known, but knowledge of these mechanisms is essential to understanding the distribution and persistence of populations in fragmented habitats. We examined these mechanisms through multiseason occupancy models that elucidated patch-occupancy dynamics of Middle Spotted Woodpeckers (Dendrocopos medius) in northwestern Spain. The number of occupied patches was relatively stable from 2000 to 2010 (15-24% of 101 patches occupied every year) because extinction was balanced by recolonization. Larger and higher quality patches (i.e., higher density of oaks >37 cm dbh [diameter at breast height]) were more likely to be occupied. Habitat quality (i.e., density of large oaks) explained more variation in patch colonization and extinction than did patch size and connectivity, which were both weakly associated with probabilities of turnover. Patches of higher quality were more likely to be colonized than patches of lower quality. Populations in high-quality patches were less likely to become extinct. In addition, extinction in a patch was strongly associated with local population size but not with patch size, which means the latter may not be a good surrogate of population size in assessments of extinction probability. Our results suggest that habitat quality may be a primary driver of patch-occupancy dynamics and may increase the accuracy of models of population survival. We encourage comparisons of competing models that assess occupancy, colonization, and extinction probabilities in a single analytical framework (e.g., dynamic occupancy models) so as to shed light on the association of habitat quality and patch geometry with colonization and extinction processes in different settings and species. © 2012 Society for Conservation Biology.

Hughes N.K.,University of New South Wales | Hughes N.K.,University of Antwerp | Kelley J.L.,University of New South Wales | Kelley J.L.,University of Western Australia | And 2 more authors.
Ecology Letters | Year: 2012

Individuals are at risk when communicating because conspicuous signals attract both conspecifics and eavesdropping predators. This predation cost of communicating has typically been attributed to signalling individuals because of their conspicuous role, and is a core concept within sexual selection and communication ecology. But, if predators are attracted to signals, then receivers, both intended or otherwise, may also find themselves at risk of predation. Here, we review the theoretical basis and empirical evidence that receiving also carries a risk of predation. We distinguish between the risks of receiving and responding to signals, and we argue that receivers of signals that are long lived, are highly predictable in time or place and/or cannot be received quickly are likely to be at greater risk of predation compared to receivers of signals without these properties. We review recent empirical evidence from a variety of taxa that supports the hypothesis that receivers (including heterospecific prey) are aware of these risks and that they modify their behaviour to balance the risks against the benefits of receiving under predation threat. We also discuss the wider implications of risky receiving for receiving and signalling behaviour in prey, as well as for the prey's predators. © 2012 Blackwell Publishing Ltd/CNRS.

Teixeira R.F.M.,University of Antwerp
Chemical Engineering Transactions | Year: 2014

Life Cycle Assessment (LCA) is a method used to quantify potential environmental impacts in the entire life cycle of a product or service, starting at raw material acquisition, production, use, and eventually its disposal. It is the leading methodology for environmental metrics today - the French government recently ran a pilot for a labelling program for consumer goods where indicators displayed in labels should be calculated using LCA. The European Commission did the same for their Product Footprint Guidelines. However, LCA features many methodological shortcomings when dealing with biophysical indicators. Land use, biodiversity and ecosystem services are relevant aspects to policy-makers and consumers, but their characterization factors are not yet accurately calculated. LCA has a hard time grasping effects that are dynamic, scale-dependent, non-linear and/or hard to quantify unambiguously. In fact, out of the four conventional types of ecosystem services (provisioning services, regulating services, cultural services and supporting services) only the first and the last are partially captured in LCA results. Similarly, out of the five drivers of change to biodiversity identified by the Millennium Ecosystem Assessment (habitat change, climate change, pollution, invasive alien species and overexploitation) only the first three are included in standard LCA calculations. This review article presents a brief assessment of how biodiversity and ecosystem services are incorporated in LCA today. The standard Life Cycle Impact Assessment models are described according to the most recent developments. Ground-breaking work is undergoing, making the field very active and constantly innovating. For example, regionalized characterization factors for the impacts of biodiversity are now available using species richness as a proxy for the overall state of biodiversity. Tools for ecosystem services have also been proposed. Finally, a compilation of some challenges ahead is listed to present several ideas for the improvement of current impact assessment methods. Copyright © 2014, AIDIC Servizi S.r.l.

Roditchev D.,CNRS Nanosciences Institute of Paris | Roditchev D.,CNRS Physics and Materials Study Laboratory | Brun C.,CNRS Nanosciences Institute of Paris | Serrier-Garcia L.,CNRS Nanosciences Institute of Paris | And 7 more authors.
Nature Physics | Year: 2015

Superconducting correlations may propagate between two superconductors separated by a tiny insulating or metallic barrier, allowing a dissipationless electric current to flow. In the presence of a magnetic field, the maximum supercurrent oscillates and each oscillation corresponding to the entry of one Josephson vortex into the barrier. Josephson vortices are conceptual blocks of advanced quantum devices such as coherent terahertz generators or qubits for quantum computing, in which on-demand generation and control is crucial. Here, we map superconducting correlations inside proximity Josephson junctions using scanning tunnelling microscopy. Unexpectedly, we find that such Josephson vortices have real cores, in which the proximity gap is locally suppressed and the normal state recovered. By following the Josephson vortex formation and evolution we demonstrate that they originate from quantum interference of Andreev quasiparticles, and that the phase portraits of the two superconducting quantum condensates at edges of the junction decide their generation, shape, spatial extent and arrangement. Our observation opens a pathway towards the generation and control of Josephson vortices by applying supercurrents through the superconducting leads of the junctions, that is, by purely electrical means without any need for a magnetic field, which is a crucial step towards high-density on-chip integration of superconducting quantum devices. © 2015 Macmillan Publishers Limited. All rights reserved.

Vandenbussche F.,Ghent University | Vaseva I.,Ghent University | Vissenberg K.,University of Antwerp | Van Der Straeten D.,Ghent University
New Phytologist | Year: 2012

The vegetative development of plants is strongly dependent on the action of phytohormones. For over a century, the effects of ethylene on plants have been studied, illustrating the profound impact of this gaseous hormone on plant growth, development and stress responses. Ethylene signaling is under tight self-control at various levels. Feedback regulation occurs on both biosynthesis and signaling. For its role in developmental processes, ethylene has a close and reciprocal relation with auxin, another major determinant of plant architecture. Here, we discuss, in view of novel findings mainly in the reference plant Arabidopsis, how ethylene is distributed and perceived throughout the plant at the organ, tissue and cellular levels, and reflect on how plants benefit from the complex interaction of ethylene and auxin, determining their shape. Furthermore, we elaborate on the implications of recent discoveries on the control of ethylene signaling. © 2012 The Authors New Phytologist. © 2012 New Phytologist Trust.

Struyf E.,University of Antwerp | Conley D.J.,Lund University
Biogeochemistry | Year: 2012

The annual fixation of dissolved Si (DSi) into terrestrial vegetation has been estimated to range from 60 to 200 Tmole, or 10-40 times more than the yearly export of DSi and biogenic Si (BSi) from the terrestrial geobiosphere to the coastal zone. Ecosystems form a large filter between primary mobilization of DSi from silicate weathering and its eventual export to the oceans, and a large reservoir of BSi accumulates in aquatic and terrestrial ecosystems. Although a number of synthesis activities within the last decade have discussed biological transformations in the terrestrial Si cycle, the timescales at which BSi is stored and recycled within ecosystems, BSi persistence and reactivity throughout soil profiles, the dependence of the BSi storage and recycling on ecological processes, the feedbacks to hydrology, the interaction with man's activities and ultimately the global relevance in Si budgets are poorly constrained. Here we discuss 5 key controls on the ability of ecosystems to filter and control the export of DSi: ecosystem biodiversity, BSi dissolution rates and reactivity, hydrology, interaction with the geosphere and anthropogenic impacts. These controls need to be further studied to better quantify the global and local importance of the terrestrial biogeochemical Si cycle and specifically the BSi reservoir in ecosystems. © 2011 Springer Science+Business Media B.V.

Wouters M.,University of Antwerp
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2014

We introduce a technique to simulate the dynamics of a thermal dilute Bose gas. With the method of the nonequilibrium statistical operator, a correction to the Gross-Pitaevskii equation (GPE) is derived. This modification of the GPE describes spontaneous scattering processes. It regularizes the ultraviolet catastrophe and captures the dynamics of the particles at all energies, including the tail of the momentum distribution. We apply our model to the simulation of an evaporative cooling quench of a two-dimensional Bose gas. © 2014 American Physical Society.

Simbo D.J.,University of Antwerp
Journal of Ethnobiology and Ethnomedicine | Year: 2010

Background: An ethnobotanical survey was undertaken to record information on medicinal plants from traditional medical practitioners in Babungo and to identify the medicinal plants used for treating diseases.Methods: Traditional Medical Practitioners (TMP's) who were the main informants were interviewed using semi-structured questionnaires and open-ended conversations. Field trips were made to the sites where TMP's harvest plants.Results: The survey identified and recorded 107 plants species from 54 plant families, 98 genera used for treating diseases in Babungo. The Asteraceae was the most represented plant family while herbs made up 57% of the total medicinal plants used. The leaf was the most commonly used plant part while concoction and decoction were the most common method of traditional drug preparation. Most medicinal plants (72%) are harvested from the wild and 45% of these have other non medicinal uses. Knowledge of the use of plants as medicines remains mostly with the older generation with few youth showing an interest.Conclusions: A divers number of plants species are used for treating different diseases in Babungo. In addition to their use as medicines, a large number of plants have other non medicinal uses. The youth should be encouraged to learn the traditional medicinal knowledge to preserve it from being lost with the older generation. © 2010 Simbo; licensee BioMed Central Ltd.

Among policy-makers and governments, there is a broad consensus that artisanal and small-scale mining (ASM) needs to be 'formalized' - embodied in a standardized legal framework that is registered in and governed by a central state system-, the basic condition being that artisanal miners are given formal property rights. This article aims to contribute to this discussion, drawing on a case study from the Eastern Democratic Republic of Congo (DRC), where it is estimated that up to 90 percent of mineral production and export is 'informal'. After having pointed out some of the theoretical assumptions behind the formalization canon, we study the challenges of formalizing the mining sector in the DRC. Next, we provide an in-depth analysis of one concrete policy measure of the Congolese government, the temporary ban on all artisanal activities. We argue that the mining ban was not only a radical example of a top-down formalization policy, but also an illustration of a bureaucratic and technical measure that compounds but does not address different problems associated with ASM: conflict, informality, poverty, illegality, state control. Looking at the empirical evidence from the DRC, we argue that these kinds of technical solutions can never address the broader socio-economic and political issues at stake. © 2012 Elsevier Ltd.

Van Dyck D.,University of Antwerp
Ultramicroscopy | Year: 2011

Incoherence in electron microscopic imaging occurs when during the observation the microscope and the object are subject to fluctuations. In order to speed up the computer simulation of the images, approximations are used that are considered as valid. In this paper we will question the validity of these approximations and show that in specific cases they can lead to erroneous results. It is shown in particular in the case of one single vibrating atom that the thermal diffuse scattering that causes the signal in HAADF STEM is not only dependent on Z but also on the mean square displacement of the atom so that it can even be large for light atoms in soft matter, provided the right HAADF aperture is used. In HREM imaging the diffuse scattering leaks out of the coherent (elastic) wave and is redistributed in the background. This might explain the mismatch in elastic contrast (Stobbs factor) especially for crystals with a thickness beyond the extinction distance, where also the HAADF signal saturates and the elastic (coherent) component vanishes. © 2011 Elsevier B.V.

Economic globalization has created the possibility that human rights can be infringed abroad. The WTO, an engine of economic globalization, has remained surprisingly immune from human rights-related complaints. I argue that its non-violation or situation complaint, by invoking impediments to the attainment of treaty objectives, could provide for redress when WTO members interfere with the right to an adequate standard of living and the continuous improvement of living conditions abroad through trade in goods. The non-violation and situation complaints reflect the shared but differentiated responsibility of WTO members for the human right to an adequate standard of living. © 2012 London School of Economics and Political Science and John Wiley & Sons Ltd.

Schuerch M.,University of Kiel | Vafeidis A.,University of Kiel | Slawig T.,University of Kiel | Temmerman S.,University of Antwerp
Journal of Geophysical Research: Earth Surface | Year: 2013

Previous predictions on the ability of coastal salt marshes to adapt to future sea level rise (SLR) neglect the influence of changing storm activity that is expected in many regions of the world due to climate change. We present a new modeling approach to quantify this influence on the ability of salt marshes to survive projected SLR, namely, we investigate the separate influence of storm frequency and storm intensity. The model is applied to a salt marsh on the German island of Sylt and is run for a simulation period from 2010 to 2100 for a total of 13 storm scenarios and 48 SLR scenarios. The critical SLR rate for marsh survival, being the maximum rate at which the salt marsh survives until 2100, lies between 19 and 22 mm yr-1. Model results indicate that an increase in storminess can increase the ability of the salt marsh to accrete with sea level rise by up to 3 mm yr-1, if the increase in storminess is triggered by an increase in the number of storm events (storm frequency). Meanwhile, increasing storminess, triggered by an increase in the mean storm strength (storm intensity), is shown to increase the critical SLR rate for which the marsh survives until 2100 by up to 1 mm yr-1 only. On the basis of our results, we suggest that the relative importance of storm intensity and storm frequency for marsh survival strongly depends on the availability of erodible fine-grained material in the tidal area adjacent to the salt marsh. © 2013. American Geophysical Union. All Rights Reserved.

Weckhuysen S.,Neurogenetics Group | Weckhuysen S.,University of Antwerp | Korff C.M.,University of Geneva
Current Neurology and Neuroscience Reports | Year: 2014

Next-generation sequencing technologies have tremendously increased the speed of gene discovery in monogenic epilepsies, enabling us to identify a genetic cause in an increasing proportion of patients, and to better understand the underlying pathophysiology of their disease. The rapid speed with which new genes are being described lately, confronts clinicians with the difficult task of keeping up to date with the continuous supply of new publications. This article aims to discuss some of the genes that were recently discovered in monogenic familial epilepsy syndromes or epileptic encephalopathies for which an underlying cause remained unknown for a long time. © 2014 Springer Science+Business Media.

Schattschneider P.,Vienna University of Technology | Verbeeck J.,University of Antwerp
Ultramicroscopy | Year: 2011

The recent creation of electron vortex beams and their first practical application motivates a better understanding of their properties. Here, we develop the theory of free electron vortices with quantized angular momentum, based on solutions of the Schrödinger equation for cylindrical boundary conditions. The principle of transformation of a plane wave into vortices with quantized angular momentum, their paraxial propagation through round magnetic lenses, and the effect of partial coherence are discussed. © 2011 Elsevier B.V.

Stas S.,Free University of Colombia | Sergeyev S.,University of Antwerp | Geerts Y.,Free University of Colombia
Tetrahedron | Year: 2010

Herein we disclose an easily applicable method for the synthesis of diketopyrrolopyrrole (DPP) derivatives comprising bithiophene moieties, with different substituents on the nitrogen atoms (Me, n-octyl, 3,5-di-tert-butylbenzyl, Boc) and on the thiophene rings (C6H13, C12H25), in good yields and purities. A comparison is made between the previously described method from literature and our more efficient approach regarding number of steps, overall yields and ease of synthesis and purification. © 2010 Elsevier Ltd. All rights reserved.

BACKGROUND: The genome of the nematode Caenorhabditis elegans contains more than 30 putative globin genes that all are transcribed. Although their translated amino acid sequences fit the globin fold, a variety of amino-acid substitutions and extensions generate a wide structural diversity among the putative globins. No information is available on the physicochemical properties and the in vivo expression. RESULTS: We expressed the globins in a bacterial system, characterized the purified proteins by optical and resonance Raman spectroscopy, measured the kinetics and equilibria of O2 binding and determined the crystal structure of GLB-1* (CysGH2 --> Ser mutant). Furthermore, we studied the expression patterns of glb-1 (ZK637.13) and glb-26 (T22C1.2) in the worms using green fluorescent protein technology and measured alterations of their transcript abundances under hypoxic conditions.GLB-1* displays the classical three-over-three alpha-helical sandwich of vertebrate globins, assembled in a homodimer associated through facing E- and F-helices. Within the heme pocket the dioxygen molecule is stabilized by a hydrogen bonded network including TyrB10 and GlnE7.GLB-1 exhibits high ligand affinity, which is, however, lower than in other globins with the same distal TyrB10-GlnE7 amino-acid pair. In the absence of external ligands, the heme ferrous iron of GLB-26 is strongly hexacoordinated with HisE7, which could explain its extremely low affinity for CO. This globin oxidizes instantly to the ferric form in the presence of oxygen and is therefore incapable of reversible oxygen binding. CONCLUSION: The presented data indicate that GLB-1 and GLB-26 belong to two functionally-different globin classes.

Nadjmi N.,University of Antwerp
Cleft Palate-Craniofacial Journal | Year: 2016

Objective: This study aimed to assess the safety and feasibility of transoral robotic surgery for the reconstruction of soft palatal clefts. Design: The application of transoral robotic surgery for soft palate muscle reconstruction was investigated. The da Vinci Surgical Robot was first used on a cadaver to assess the optimal positioning of the patient and the robot. The robot was then used for the dissection and reconstruction of palatal muscles in 10 consecutive patients with palatal clefts. The procedures were documented using video and still photography. A group of 30 control patients were subjected to surgery with manual instruments. Surgical and clinical outcomes were evaluated with at least 6 months of follow-up (8± 1 months). Results: The use of the surgical robot on a cadaver provided great dexterity and excellent 3D depth perception. The transoral access was efficient and safe for the precise dissection, reorientation, and suturing of palatal muscles. In our series, the surgical duration was longer for the robotic approach than for the manual approach (87 ± 6 minutes versus 122 ± 8 minutes, P <.0001). No intraoperative or postoperative complications occurred in either group. Conclusions: A robotic surgical approach can be used safely for palatal surgery. We believe that the precise dissection of the palatal muscles provided by the robotic system might reduce damage to the vascularization and innervation of these muscles, as well as damage to the mucosal surfaces that could cause fistula formation. In addition, this technique might improve palatal function and Eustachian tube function in cleft palate patients. © Copyright 2016 American Cleft Palate-Craniofacial Association.

Lacroix J.J.,University of Chicago | Labro A.J.,University of Antwerp | Bezanilla F.,University of Chicago
Biophysical Journal | Year: 2011

The charge versus voltage relation of voltage-sensor domains shifts in the voltage axis depending on the initial voltage. Here we show that in nonconducting W434F Shaker K + channels, a large portion of this charge-voltage shift is apparent due to a dramatic slowing of the deactivation gating currents, IgD (with τ up to 80 ms), which develops with a time course of ∼1.8 s. This slowing in Ig D adds up to the slowing due to pore opening and is absent in the presence of 4-aminopyridine, a compound that prevents the last gating step that leads to pore opening. A remaining 10-15 mV negative shift in the voltage dependence of both the kinetics and the charge movement persists independently of the depolarizing prepulse duration and remains in the presence of 4-aminopyridine, suggesting the existence of an intrinsic offset in the local electric field seen by activated channels. We propose a new (to our knowledge) kinetic model that accounts for these observations. © 2011 by the Biophysical Society.

Chinese herbs nephropathy (CHN) and Balkan endemic nephropathy (BEN) are chronic tubulointerstitial renal diseases associated with urothelial carcinoma. The clinical expression and pathological lesions observed at different stages of CHN and BEN are strikingly similar. Both have been linked to exposure to aristolochic acid (AA), a powerful nephrotoxin and human carcinogen. Jelakovi et al. present molecular epidemiological evidence relating urothelial carcinoma in patients with BEN to dietary exposure to AA. It is time to abandon the terms CHN and BEN and introduce aristolochic acid nephropathy to cover both clinical conditions. © 2012 International Society of Nephrology.

Rougny R.,University of Antwerp
Nuclear Physics B - Proceedings Supplements | Year: 2010

The CMS measurement of the charged hadron pseudorapidity and transverse momentum distributions in minimum bias pp collisions at √s=0.9, 2.36 and 7 TeV, is presented. The charged hadron yield results were obtained using the inner silicon tracker, by means of 3 different methods: counting the number of reconstructed hits, the number of hit pairs (tracklet-based algorithm), and the number of fully reconstructed particle tracks. The obtained data is compared with other experiment results, several Monte-Carlo models and tunes, as well as some current theoretical models. © 2010 Elsevier B.V.

Evenepoel P.,University Hospitals Leuven | D'Haese P.,University of Antwerp | Brandenburg V.,RWTH Aachen
Kidney International | Year: 2015

For more than a decade, the Wnt-β-catenin pathway has been the focus of intense basic and clinical research in the bone field because of its importance in skeletal development and maintenance of bone mass. Wnt activation increases bone formation and decreases bone resorption. The Wnt-β-catenin signaling pathway is tightly regulated by several inhibitors, among which Dickkopf-related protein 1 (DKK1) and sclerostin have been most comprehensively studied. Mounting evidence indicates that a disturbed Wnt-β-catenin signaling is also implicated in the pathogenesis of the chronic kidney disease-associated bone and mineral disorder (CKD-MBD) and affects its various components. DKK1 and sclerostin, more specifically, may be involved in the intense cross-talk between the kidneys, vasculature, and bone. Studies exploring clinical correlates of circulating sclerostin and DKK1 levels so far yielded conflicting results. Biological variability and analytical issues account at least partly for this inconsistency. Antibodies neutralizing Wnt inhibitors may be an appealing strategy to prevent or treat CKD-MBD. Caution is however warranted as sclerostin not only opposes mineralization in the bone but possibly also in the vasculature. Additional studies are required to define determinants of Wnt inhibitors in CKD and to evaluate the efficacy and safety of recently introduced pharmaceuticals targeting these inhibitors. © 2015 International Society of Nephrology.

Giannantoni A.,University of Perugia | Bini V.,University of Perugia | Dmochowski R.,Vanderbilt University | Hanno P.,University of Pennsylvania | And 3 more authors.
European Urology | Year: 2012

Context: Different types of behavioural, dietary, interventional, pharmacologic, and surgical therapies have been used to treat painful bladder syndrome/interstitial cystitis (PBS/IC). Because of the paucity of randomised placebo-controlled studies on different treatments, an evidence-based management approach has not yet been developed. Objective: To critically review and synthesize data from a wide range of current therapeutic approaches to PBS/IC, to quantify the effect size from randomised controlled trials (RCTs), and to reach clinical agreement on the efficacy of treatments for PBS/IC. Evidence acquisition: We performed a systematic review of the literature to identify articles published between 1990 and September 2010 on the management of PBS/IC. We included articles restricted to the English language published since 1990 to date that reported on oral and intravesical treatment, multimodal or combined treatment, and surgical treatment. For all RCTs, standardised mean differences (SMDs) were extracted and combined in a meta-analysis applying a random-effect model that incorporated the heterogeneity of effects. The four outcomes assessed in all studies were a change in the Interstitial Cystitis Symptom Index (ICSI), pain, urgency, and frequency. Non-RCTs (nRCTs) were analysed with a narrative synthesis of the evidence from all research designs. Evidence synthesis: We included 7709 adult patients from 29 RCTs and 57 nRCTs. Meta-analysis of RCTs showed that only cyclosporine A provided a simultaneous great effect size of SMD on ICSI, pain, and frequency. Amitriptyline at different dosages showed a great effect size of SMD on pain and urgency or on ICSI and frequency. The remaining RCTs showed sporadic significant changes in only one of the four considered parameters. The attributed levels of evidence for treatments reported in RCTs were 1b; grades of recommendations ranged from A to C. According to the Jadad score, 11 RCTs were high-quality studies. Meta-analysis of RCTs showed a great heterogeneity in the applied methodologies, clinical outcomes assessed, and the obtained results in different studies. The results from the nRCTs showed that the most frequently adopted treatment is oral pentosan polysulfate and that the use of botulinum A toxin intradetrusorial injections in PBS/IC is increasing. A high heterogeneity in drugs and treatment modalities, clinical outcomes, and obtained results was also found for nRCTs. Conclusions: Limited evidence exists for the few treatments for PBS/IC. The lack of definitive conclusions is due to the great heterogeneity in methodology, symptoms assessment, duration of treatment, and follow-up in both RCTs and nRCTs. © 2011 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Marklund M.,Umea University | Verbraecken J.,University of Antwerp | Randerath W.,Witten/Herdecke University
European Respiratory Journal | Year: 2012

Mandibular advancement devices (MADs) represent the main non-continuous positive airway pressure (non-CPAP) therapy for patients with obstructive sleep apnoea (OSA). The aim of the European Respiratory Society Task Force was to review the evidence in favour of MAD therapy. Effects of tongue-retaining devices are not included in this report. Custom-made MADs reduce apnoea/hypopnoea index (AHI) and daytime sleepiness compared with placebo devices. CPAP more effectively diminishes AHI, while increasing data suggest fairly similar outcomes in relation to symptoms and cardiovascular health from these treatments. Patients often prefer MADs to CPAP. Milder cases and patients with a proven increase in upper airway size as a result of mandibular advancement are most likely to experience treatment success with MADs. A custom-made device titrated from an initial 50% of maximum mandibular advancement has been recommended. More research is needed to define the patients who will benefit from MAD treatment compared with CPAP, in terms of the effects on sleep-disordered breathing and on other diseases related to OSA. In conclusion, MADs are recommended for patients with mild to moderate OSA (Recommendation Level A) and for those who do not tolerate CPAP. The treatment must be followed up and the device adjusted or exchanged in relation to the outcome. Copyright©ERS 2012.

Lebeer J.,University of Antwerp
NeuroRehabilitation | Year: 2016

BACKGROUND: The theory of Structural Cognitive Modifiability and Mediated Learning Experience of Reuven Feuerstein states that individuals with brain impairment, because of congenital or acquired origin, may substantially and structurally improve their cognitive functioning, by a systematic intervention based on a specific, criteria-based type of interaction ("mediated learning"). Three application systems are based on it: a dynamic-interactive assessment of learning capacity and processes of learning, the LPAD (Learning Propensity Assessment Device); a cognitive intervention program called "Instrumental Enrichment Program", which trains cognitive, metacognitive and executive functions; and a program, which is oriented at working in context, Shaping Modifying Environments. These programs have been applied in widely different target groups: from children and young adults with learning and developmental disabilities, at risk of school failure, or having failed at school, because of socio-economic disadvantage or congenital neurological impairment; disadvantaged youngsters and adults in vocational training, to elderly people at the beginning of a dementia process. Experience with cognitive rehabilitation of children and adults with acquired brain damage, has been relatively recent, first in the Feuerstein Institute's Brain Injury Unit in Jerusalem, later in other centers in different parts of the world; therefore scientific data are scarce. OBJECTIVES: The purpose of this paper is to examine how the Feuerstein-approach fits into the goals and proposed approaches of cognitive rehabilitation, and to explore its relevance for assessment and intervention in individuals with congenital or acquired brain damage. METHODS: The methodology of the Feuerstein approach consists of four pillars: dynamic assessment, cognitive activation, mediated learning and shaping a modifying environment. The criteria of mediated learning experience are explained with specific reference to people with acquired brain injury. The procedure of learning propensity assessment device uses visuo-spatial and verbal tasks known from neuropsychological assessment (such as Rey's complex figure drawing), as well as a in a pre-test - brief intervention - post-test format. Cognitive activation is done in various ways: a paper-and-pencil relatively content-free program called "instrumental enrichment", with transfer of learned principles into daily life situations, followed by metacognitive feedback. Four case histories of acquired brain damage are analyzed: a 19 year old man with extensive post-astrocytoma frontotemporal brain lesions; a 19 year old man with bilateral frontal and right temporal and parieto-occipital parenchymatous destruction after a traumatic brain injury; a 24 year old man with hemispherectomy for intractable epilepsy because of Sturge-Weber syndrome; and a 30-year old man with left porencephalic cyst after cerebral hemorrhage. RESULTS: Structural cognitive improvement could be demonstrated in positive change scores in visuo-spatial memory, associative and verbal memory, abstract thinking, and organizing tasks, even more than 10 years post-TBI. In some cases a rise in IQ has been documented. Improvement in daily life functioning and academic skills (re)learning has also been seen. CONCLUSIONS: Though impossible to claim scientific evidence, the case histories nevertheless suggest the importance of interactive assessment in designing intervention programs which have sufficient intensity, frequency, duration and consistency of mediation; furthermore, an essential ingredient is the ecological approach which requires working with the patient and the whole network around; a firm "belief system" or that modifiability is possible even with severe brain damage and many years after the injury; a cognitive, metacognitive and executive approach, and a quality of interaction according to criteria of mediated learning. They suggest that Feuerstein approach may offer interesting perspectives to cognitive rehabilitation. More extensive research is needed to provide a broader scientific evidence base. © 2016 - IOS Press and the authors.

Objective: The aim of this study was to investigate the influence of the type of current and the frequency of impulses of electrical stimulation on the contraction of pelvic muscles with different fibre content. Materials and methods: Electrical stimulation of complete muscles from Wistar rats was performed in vitro with a biphasic square wave current and with a bipolar mid-frequency current at frequencies between 2 and 100Hz. The parameters of the resulting isometric contraction were determined. Results: The iliococcygeus and pubococcygeus, both with mainly fast-twitch muscle fibres, showed maximal contraction with a biphasic current with square wave pulses at 50 Hz and 60Hz. The best result in the soleus, with mainly slow-twitch fibres, was with 33Hz. The mid-frequency current needed a higher intensity to reach lower contraction values but was more effective at the very low frequencies. Conclusions: Current type and frequency of electrical impulses change the electrically induced contraction in pelvic muscles substantially. This should be taken into account when designing and evaluating specific electrical stimulation of pelvic floor muscles aiming at improving either fast contraction or support, or both. From these data, optimal stimulation programmes may be proposed for mainly slow and mainly fast pelvic floor muscles, which need to be evaluated in a clinical setting. © 2016 Informa UK Limited, trading as Taylor & Francis Group.

Broeckx N.,University of Antwerp
European Journal of Health Law | Year: 2013

In this article, the case of living organ donation by minors is discussed. A distinction can be made between minors who are in fact already competent and those who are not. Minors who are in fact competent, should be able to decide on organ donation under the same conditions as competent adults. Incompetent minors could be allowed to act as living organ donors under exceptional circumstances on the basis of a best interest test. Decisions on living organ donation by incompetent minors should be embedded into a procedural framework in which parental consent, the approval of an independent body of health professionals, and the minor's wishes play a substantial role. © Koninklijke Brill NV, Leiden, 2013.

Rousseau R.,k-Technology | Rousseau R.,Catholic University of Leuven | Rousseau R.,University of Antwerp
Journal of the American Society for Information Science and Technology | Year: 2012

We introduce the notions of congruous indicator of relative performance and congruous indicator of absolute performance. These notions are very similar to the notions of independence and consistency,yet slightly different. It is shown that percentile rank scores, as recently introduced by Leydesdorff, Bornmann, Mutz, and Opthof (2011), are strictly congruous indicators of relative performance, and similarly, that the Integrated Impact Indicator (I3), introduced by Leydesdorff and Bornmann (2011), is a strictly congruous indicator of absolute performance. Our analysis highlights the challenge of finding adequate axioms for ranking and for research evaluation. © 2011 ASIS&T.

Egghe L.,Hasselt University | Egghe L.,University of Antwerp
Journal of the American Society for Information Science and Technology | Year: 2012

The author presents a different view on properties of impact measures than given in the paper of De Visscher (2011). He argues that a good impact measure works better when citations are concentrated rather than spread out over articles. The author also presents theoretical evidence that the g-index and the R-index can be close to the square root of the total number of citations, whereas this is not the case for the A-index. Here the author confirms an assertion of De Visscher. © 2012 ASIS & T.

Pappin M.,University of the Free State | Wouters E.,University of Antwerp | Booysen F.L.R.,University of the Free State
BMC Public Health | Year: 2012

Background: HIV/AIDS and depression are projected to be the two leading causes of disability by 2030. HIV/AIDS and anxiety/depression are interlinked. People suffering from depression may be more likely to engage in risky sexual behaviour, and therefore at greater risk of contracting HIV. An HIV + diagnosis may trigger symptoms of anxiety and depression, which may in turn result in risky sexual behaviour and the spread of HIV. This study explores correlates of anxiety and depression in patients enrolled in a public sector ART programme in South Africa. Methods. Interviews were conducted with 716 patients initiating ART at twelve public health care facilities in the Free State. Symptoms of anxiety and depression were measured using the Hospital Anxiety and Depression Scale (HADS). An 8+ cut-off was used to identify possible cases of anxiety and depression. Multivariate logistic regression analysis, using STATA Version 11, was performed to identify correlates of anxiety and depression. Results: The prevalence of symptoms of respectively anxiety and depression amongst this study population in the Free State was 30.6% and 25.4%. The multivariate logistic regression analyses identified five correlates of symptoms of anxiety and depression. Disruptive side effects (OR = 3.62, CI 1.95-6.74) and avoidant coping (OR = 1.42, CI 1.22-1.65) were associated with a greater number of symptoms of anxiety. Stigma was associated with an increase in symptoms of anxiety (OR = 1.14, CI 1.07-1.21) and of depression (OR = 1.13, CI 1.06-1.20), while being a widow (OR = 0.30, CI 0.13-0.69) and participating in a support group (OR = 0.21, CI 0.05-0.99) were associated with decreased symptoms of depression. Conclusions: The findings from the study provide valuable insights into the psychosocial aspects of the Free State public-sector ART programme. Combined with the literature on the intricate link between mental health problems and treatment outcomes our results emphasise firstly, the necessity that resources be allocated for both screening and treating mental health problems and, secondly, the need for interventions that will encourage support-group participation, address ART side effects, reduce maladaptive coping styles, and minimise the stigma associated with symptoms of anxiety and/or depression. © 2012 Pappin et al; licensee BioMed Central Ltd.

Egghe L.,Hasselt University | Guns R.,University of Antwerp
Journal of the American Society for Information Science and Technology | Year: 2012

In a previous work (Egghe, 2011), the first author showed that Benford's law (describing the logarithmic distribution of the numbers 1, 2, ..., 9 as first digits of data in decimal form) is related to the classical law of Zipf with exponent 1. The work of Campanario and Coslado (2011), however, shows that Benford's law does not always fit practical data in a statistical sense. In this article, we use a generalization of Benford's law related to the general law of Zipf with exponent β > 0. Using data from Campanario and Coslado, we apply nonlinear least squares to determine the optimal β and show that this generalized law of Benford fits the data better than the classical law of Benford. © 2012 ASIS&T.

Egghe L.,Hasselt University | Egghe L.,University of Antwerp
Scientometrics | Year: 2010

This paper proves two regularities that where found in the paper (Larivière et al. (2007). Long-term patterns in the aging of the scientific literature, 1900-2004. In Proceedings of ISSI 2007. CSIC, Madrid, Spain, pp. 449-456.). The first is that the mean as well as the median reference age increases in time. The second is that the Price Index decreases in time. Using an exponential literature growth model we prove both regularities. Hence we show that the two results do not have a special informetric reason but that they are just a mathematical consequence of a widely accepted simple literature growth model. © 2009 Akadémiai Kiadó, Budapest, Hungary.

Egghe L.,Hasselt University | Egghe L.,University of Antwerp
Journal of the American Society for Information Science and Technology | Year: 2010

Similarity measures, such as the ones of Jaccard, Dice, or Cosine, measure the similarity between two vectors. A good property for similarity measureswould be that, if we add a constant vector to both vectors, then the similarity must increase.We show that Dice and Jaccard satisfy this property while Cosine and both overlap measures do not. Adding a constant vector is called, in Lorenz concentration theory, "nominal increase" and we show that the stronger "transfer principle" is not a required good property for similarity measures. Another good property is that, when we have two vectors and if we add one of these vectors to both vectors, then the similarity must increase. Now Dice, Jaccard, Cosine, and one of the overlap measures satisfy this property, while the other overlap measure does not. Also a variant of this latter property is studied. © 2010 ASIS&T.

Herrebout W.,University of Antwerp
Topics in Current Chemistry | Year: 2014

Because they create a weakly interacting environment which, combined with the low temperatures used, leads to small bandwidths and thus facilitates the detection of complex bands only slightly shifted from the monomer modes, solutions in liquefied inert gases have proven to be an ideal medium to study molecular complexes held together by weak and medium-strong C—X...Y (with X=I, Br, Cl and Y=O, N, S, F, Cl, π,...) halogen bonds. In this chapter, experimental setups for infrared and Raman study of cryosolutions are described, and general methodologies used to examine weakly bound molecular complexes are discussed. The methods are illustrated using data obtained for a variety of halogen-bonded complexes involving, amongst others, the trifluorohalomethanes CF3Cl, CF3Br, and CF3I, and a variety of Lewis bases. The results are compared with theoretical data obtained from ab initio calculations, and with experimental and theoretical data obtained for complexes involving weak C–H proton donors such as CHF3. Preliminary data for mixed proton donor/halogen donors such as CHClF2, CHBrF2 are also discussed. © Springer-Verlag Berlin Heidelberg 2014.

Sahin H.,University of Antwerp
Physical Review B - Condensed Matter and Materials Physics | Year: 2015

Recent experimental studies showed that formation of a two-dimensional crystal structure of nitrogenated holey graphene (NHG) is possible. Similar to graphene, NHGs have an atomically thin and strong crystal structure. Using first-principles calculations, we investigate the structural, phononic, and thermal properties of monolayer NHG crystal. Our charge analysis reveals that the charged holey sites of NHG provide a reactive ground for further functionalization by adatoms or molecules. We also found that similar to graphene, the NHG structure has quite high-frequency phonon modes and the presence of nitrogen atoms leads to the emergence of additional vibrational modes. Our phonon analysis reveals the presence of three characteristic Raman-active modes of NHG. Furthermore, the analysis of constant-volume heat capacity showed that the NHG structure has a linear temperature dependence in the low-temperature region. The strong lattice structure and unique thermal properties of the NHG crystal structure are desirable in nanoscale device applications. © 2015 American Physical Society. ©2015 American Physical Society.

Engbarth M.A.,University of Bath | Bending S.J.,University of Bath | Milosevic M.V.,University of Antwerp
Physical Review B - Condensed Matter and Materials Physics | Year: 2011

Hall probe magnetometry has been used to investigate the magnetization of individual cylindrically shaped Pb nanowires grown by electrocrystallization on a highly oriented pyrolytic graphite electrode. These measurements have been interpreted by comparison with three-dimensional Ginzburg-Landau (GL) calculations for nanowires with our sample parameters. We find that the measured superheating field and the critical field for surface superconductivity are strongly influenced by the temperature-dependent coherence length, ξ(T) and penetration depth λ(T) and their relationship to the nanowire diameter. As the temperature is increased toward Tc this drives a change in the superconductor-normal transition from first order irreversible to first order reversible and finally second order reversible. We find that the geometrical flux confinement in our type-I nanowires leads to the formation of a one-dimensional row of single-quantum vortices. While GL calculations show a quite uniform distribution of vortices in thin nanowires, clear vortex bunching is found as the diameter increases, suggesting a transition to a more classical type-I behavior. Subtle changes in minor magnetization loops also indicate that slightly different flux configurations can form with the same vorticity, which depend on the sample history. © 2011 American Physical Society.

Jaspers J.,University of Antwerp
Journal of Pragmatics | Year: 2011

The purpose of this article is to show how subordinate groups such as minority language users can enjoy and employ the linguistic possibilities afforded by the unequal structures they live in. On the basis of ethnographically collected data on linguistic practices at a secondary school in Antwerp, Belgium, I will indicate how a group of ethnic minority students engaged in making ambiguous linguistic caricatures by stylizing incompetent or broken Dutch - what they called talking Illegal ('. Illegaal spreken', in Dutch). This appeared to be a contradictory practice: students talked Illegal as a way of faking incompetence and playfully but critically highlighting the contours of the unequal social frame surrounding them; at the same time such stylizations could also involve harsh stigmatization of classmates and help construct dominant positions on the classroom floor, and in this way they were reproducing and benefiting from the very structures they were critically highlighting on other occasions. © 2010 Elsevier B.V.

Boisdenghien Z.,Vrije Universiteit Brussel | Van Alsenoy C.,University of Antwerp | De Proft F.,Vrije Universiteit Brussel | Geerlings P.,Vrije Universiteit Brussel
Journal of Chemical Theory and Computation | Year: 2013

Although a lot of work has been done on the chemical relevance of the atom-condensed linear response kernel χAB regarding inductive, mesomeric, and hyperconjugative effects as well as (anti)aromaticity of molecules, the same cannot be said about its not condensed form χ(r,r′). Using a single Slater determinant KS type ansatz involving second order perturbation theory, we set out to investigate the linear response kernel for a number of judiciously chosen closed (sub)shell atoms throughout the periodic table and its relevance, e.g., in relation to the shell structure and polarizability. The numerical results are to the best of our knowledge the first systematic study on this noncondensed linear response function, the results for He and Be being in line with earlier work by Savin. Different graphical representations of the kernel are presented and discussed. Moreover, a frontier orbital approach has been tested illustrating the sensitivity of the nonintegrated kernel to the nodal structure of the orbitals. As a test of our method, a numerical integration of the linear response kernel was performed, yielding an accuracy of 10-4. We also compare calculated values of the polarizability tensor and their evolution throughout the periodic table to high-level values found in the literature. © 2013 American Chemical Society.

Egghe L.,Hasselt University | Egghe L.,University of Antwerp
Scientometrics | Year: 2013

The central area indices and the central interval indices, as introduced in Dorta-González and Dorta-González (Scientometrics 88(3):729-745, 2011), are studied from a theoretical point of view. They are defined in order to yield higher impact values of "selective" authors (i. e., authors with concentrated number of citations over their publications). We show that this property is not valid for every citation distribution. However, if Zipf's law is adopted for the citation distribution, we can show that the central area indices and the central interval indices have indeed higher values for more selective authors. © 2012 Akadémiai Kiadó, Budapest, Hungary.

van der Werf I.M.,University of Antwerp
European Journal of Human Genetics | Year: 2016

In approximately 20% of individuals with Kagami-Ogata syndrome (KOS14, MIM 608149), characterized by a bell-shaped thorax with coat-hanger configuration of the ribs, joint contractures, abdominal wall defects and polyhydramnios during the pregnancy, the syndrome is caused by a maternal deletion of the imprinted gene cluster in chromosome 14q32.2. Most deletions reported so far included one or both of the differentially methylated regions (DMRs) – DLK1/MEG3 IG-DMR and MEG3-DMR. We present two unrelated families with two affected siblings each, presenting with classical KOS14 due to maternally inherited microdeletions. Interestingly, all four patients have lived through to adulthood, even though mortality rates for patients with KOS14 due to a microdeletion are relatively high. In the first family, none of the DMRs is included in the deletion and the methylation status is identical to that of controls. Deletions that do not encompass the DMRs in this region are thus sufficient to elicit the full KOS14 phenotype. In the second family, a partially overlapping deletion including both DMRs and MEG3 was detected. In summary, we show that patients with KOS14 can live into adulthood, that causal deletions do not have to include the DMRs and that consequently a normal methylation pattern does not exclude KOS14.European Journal of Human Genetics advance online publication, 13 July 2016; doi:10.1038/ejhg.2016.82. © 2016 Macmillan Publishers Limited

Gilsing V.,University of Antwerp
Journal of Product Innovation Management | Year: 2016

This article considers the evolution of interfirm networks within a context of technological change. More specifically, it studies the evolution of structural and positional embeddedness in a network of technology-based alliances when it moves from an early period of invention creation to a subsequent period of new product development and commercialization. Empirically, we study the evolution of technology-based alliance networks in the biopharmaceutical industry over a period of about 25 years, from 1975 until 1999. Examining interorganizational networks over such an extended time period allows us to move beyond more static approaches that have characterized most network studies until now, and consider network evolution along its various phases of birth, growth, and early maturation instead. Our findings indicate that the evolution of both structural and positional embeddedness does not follow the common idea of a path of linear progression, but instead strongly exhibits nonlinearity by resembling a sigmoid pattern. These findings have a number of implications. First, the break in the process of linear progression contrasts with the standing literature that (implicitly) assumes the informational and resource value of a network structure to remain constant over time or to evolve linearly from carrying low value to progressively higher value. Instead, our finding that the evolution of structural and positional embeddedness is nonlinear echoes the speculative idea, as expressed by Gulati and Garguilo, that network change may possibly be nonlinear when seen over the long run. A second implication concerns the validity of standing insights from the social network literature such as Coleman's theory of social capital and Burt's theory of structural holes. These theories may not apply to the extent that there are strong changes in environmental conditions like environmental uncertainty and/or munificence, such as during a transition phase as considered in this study. © 2015 Product Development & Management Association.

Loeys B.L.,University of Antwerp
Drug Discovery Today | Year: 2015

The study of mouse models for Marfan syndrome, an autosomal dominant connective tissue disorder caused by mutations in fibrillin-1 (FBN1), has shifted our understanding of the pathogenesis of thoracic aortic aneurysm significantly. Multiple lines of evidence support the notion that dysregulation of canonical and noncanonical transforming growth factor (TGF)β signaling is the responsible pathway in this and related thoracic aortic aneurysm conditions. This exciting knowledge has opened numerous new treatment options, including antagonism of the angiotensin II receptor blocker type 1 (AT1R). In this review, we summarize the current knowledge, the first human losartan Marfan trial results and future therapeutic perspectives for aortic disease in Marfan patients. © 2014 Elsevier B.V. All rights reserved.

Arsoski V.V.,University of Belgrade | Tadic M.Z.,University of Belgrade | Peeters F.M.,University of Antwerp
Physical Review B - Condensed Matter and Materials Physics | Year: 2013

Neutral excitons in strained axially symmetric In(Ga)As/GaAs quantum dots with a ringlike shape are investigated. Similar to experimental self-assembled quantum rings, the analyzed quantum dots have volcano-like shapes. The continuum mechanical model is employed to determine the strain distribution, and the single-band envelope function approach is adopted to compute the electron states. The hole states are determined by the axially symmetric multiband Luttinger-Kohn Hamiltonian, and the exciton states are obtained from an exact diagonalization. We found that the presence of the inner layer covering the ring opening enhances the excitonic Aharonov-Bohm (AB) oscillations. The reason is that the hole becomes mainly localized in the inner part of the quantum dot due to strain, whereas the electron resides mainly inside the ring-shaped rim. Interestingly, larger AB oscillations are found in the analyzed quantum dot than in a fully opened quantum ring of the same width. Comparison with the unstrained ringlike quantum dot shows that the amplitude of the excitonic Aharonov-Bohm oscillations are almost doubled in the presence of strain. The computed oscillations of the exciton energy levels are comparable in magnitude to the oscillations measured in recent experiments. © 2013 American Physical Society.

Grujic M.,University of Belgrade | Tadic M.,University of Belgrade | Peeters F.M.,University of Antwerp
Physical Review B - Condensed Matter and Materials Physics | Year: 2013

The mean-field Hubbard model is used to investigate the formation of the antiferromagnetic phase in hexagonal graphene rings with inner zigzag edges. The outer edge of the ring was taken to be either zigzag or armchair, and we found that both types of structures can have a larger antiferromagnetic interaction as compared with hexagonal dots. This difference could be partially ascribed to the larger number of zigzag edges per unit area in rings than in dots. Furthermore, edge states localized on the inner ring edge are found to hybridize differently than the edge states of dots, which results in important differences in the magnetism of graphene rings and dots. The largest staggered magnetization is found when the outer edge has a zigzag shape. However, narrow rings with armchair outer edge are found to have larger staggered magnetization than zigzag hexagons. The edge defects are shown to have the least effect on magnetization when the outer ring edge is armchair shaped. © 2013 American Physical Society.

Schaller J.,TU Dresden | Struyf E.,University of Antwerp
Hydrobiologia | Year: 2013

The decomposition rate of plant litter is important for the carbon cycle. Element stoichiometry and hardly degradable carbon compounds are main factors controlling the decomposition rate of plant litter. Recent research has linked these factors to silicon availability during plant growth, but no research focused on the effect of silicon on litter decomposition. We therefore conducted a batch experiment to assess the effect of silicon availability to plants on litter degradation, nutrient release and multi elemental stoichiometry. Experiments were conducted in the presence or absence of invertebrate shredders (Gammaruspulex). We show that nutrient content (affected by silicon availability during plant growth) has a strong impact on nutrient turnover, while DOC, N, and Mn were mainly controlled by invertebrate feeding. The carbon turnover during microbial litter decay was strongly influenced by the silicon availability during plant growth, with quicker potential C turnover of litter with higher silicon content. In both Si-rich and Si-poor litter, feeding by invertebrate shredders positively impacted turnover rates, but effects were less pronounced in Si-rich litter. It can be concluded that silicon availability in wetlands dominated by reed plays an important role in carbon sequestration, nutrient cycling, and remobilization during aquatic litter decay. © 2013 Springer Science+Business Media Dordrecht.

Bocksteins E.,University of Antwerp
Journal of General Physiology | Year: 2016

Members of the electrically silent voltage-gated K+ (Kv) subfamilies (Kv5, Kv6, Kv8, and Kv9, collectively identified as electrically silent voltage-gated K+ channel [KvS] subunits) do not form functional homotetrameric channels but assemble with Kv2 subunits into heterotetrameric Kv2/KvS channels with unique biophysical properties. Unlike the ubiquitously expressed Kv2 subunits, KvS subunits show a more restricted expression. This raises the possibility that Kv2/KvS heterotetramers have tissue-specific functions, making them potential targets for the development of novel therapeutic strategies. Here, I provide an overview of the expression of KvS subunits in different tissues and discuss their proposed role in various physiological and pathophysiological processes. This overview demonstrates the importance of KvS subunits and Kv2/KvS heterotetramers in vivo and the importance of considering KvS subunits and Kv2/KvS heterotetramers in the development of novel treatments. © 2016 Bocksteins.

Adams F.C.,University of Antwerp | Barbante C.,CNR Institute of Neuroscience | Barbante C.,University of Venice
Spectrochimica Acta - Part B Atomic Spectroscopy | Year: 2013

Nanoscience has outgrown its infancy, and nanotechnology has found important applications in our daily life - with many more to come. Although the central concepts of the nano world, namely the changes of particular physical properties on the length scale of individual atoms and molecules, have been known and developed for quite some time already, experimental advances since the 1980s and recognition of the potential of nanomaterials led to a genuine breakthrough of the inherently multidisciplinary nanoscience field. Analytical nanoscience and nanotechnology and especially the use of micro and nano electro mechanical systems, of the quantum dots and of mass spectrometry, currently provide one of the most promising avenues for developments in analytical science, derived from their two main fields of action, namely (a) the analysis of nano-structured materials and (b) their use as new tools for analysis. An overview is given of recent developments and trends in the field, highlighting the importance and point out future directions, while also touching drawbacks, such as emerging concerns about health and environmental issues. © 2013 Elsevier B.V.

De Backer C.J.S.,University of Antwerp | Hudders L.,Ghent University
Meat Science | Year: 2015

The aim of this work is to explore the relation between morality and diet choice by investigating how animal and human welfare attitudes and donation behaviors can predict a meat eating versus flexitarian versus vegetarian diet. The results of a survey study (N=299) show that animal health concerns (measured by the Animal Attitude Scale) can predict diet choice. Vegetarians are most concerned, while full-time meat eaters are least concerned, and the contrast between flexitarians and vegetarians is greater than the contrast between flexitarians and full-time meat eaters. With regards to human welfare (measured by the Moral Foundations Questionnaire), results show that attitudes towards human suffering set flexitarians apart from vegetarians and attitudes towards authority and respect distinguish between flexitarians and meat eaters. To conclude, results show that vegetarians donate more often to animal oriented charities than flexitarians and meat eaters, while no differences between the three diet groups occur for donations to human oriented charities. © 2014 Elsevier Ltd.

Niermann T.,TU Berlin | Verbeeck J.,University of Antwerp | Lehmann M.,TU Berlin
Ultramicroscopy | Year: 2014

We demonstrate the production of an ordered array of electron vortices making use of an electron optical setup consisting of two electrostatic biprisms. The biprism filaments are oriented nearly orthogonal with respect to each other in a transmission electron microscope. Matching the position of the filaments, we can choose to form different topological features in the electron wave. We outline the working principle of the setup and demonstrate first experimental results. This setup partially bridges the gap between angular momentum carried by electron spin, which is intrinsic and therefore present in any position of the wave, and angular momentum carried by the vortex character of the wave, which can be extrinsic depending on the axis around which it is measured. © 2013 Elsevier B.V.

Krstajic P.M.,University of Belgrade | Peeters F.M.,University of Antwerp
Physical Review B - Condensed Matter and Materials Physics | Year: 2013

The relation between the energy and momentum of plasmarons in bilayer graphene is investigated within the Overhauser approach, where the electron-plasmon interaction is described as a field theoretical problem. We find that the Dirac-like spectrum is shifted by ΔE(k) ∼100÷150meV depending on the electron concentration ne and electron momentum. The shift increases with electron concentration as the energy of plasmons becomes larger. The dispersion of plasmarons is more pronounced than in the case of single layer graphene, which is explained by the fact that the energy dispersion of electrons is quadratic and not linear. We expect that these predictions can be verified using angle-resolved photoemission spectroscopy (ARPES). © 2013 American Physical Society.

Rossell M.D.,Empa - Swiss Federal Laboratories for Materials Science and Technology | Abakumov A.M.,University of Antwerp | Ramasse Q.M.,Daresbury Laboratory | Erni R.,Empa - Swiss Federal Laboratories for Materials Science and Technology
ACS Nano | Year: 2013

Determining the structure-to-property relationship of materials becomes particularly challenging when the material under investigation is dominated by defects and structural disorder. Knowledge on the exact atomic arrangement at the defective structure is required to understand its influence on the functional properties. However, standard diffraction techniques deliver structural information that is averaged over many unit cells. In particular, information about defects and order-disorder phenomena is contained in the coherent diffuse scattering intensity which often is difficult to uniquely interpret. Thus, the examination of the local disorder in materials requires a direct method to study their structure on the atomic level with chemical sensitivity. Using aberration-corrected scanning transmission electron microscopy in combination with atomic-resolution electron energy-loss spectroscopy, we show that the controversial structural arrangement of the Fe2O2+δ layers in the mixed ionic-electronic conducting Sr4Fe6O12+δ perovskite can be unambiguously resolved. Our results provide direct experimental evidence for the presence of a nanomixture of "ordered" and "disordered" domains in an epitaxial Sr4Fe6O12+δ thin film. The most favorable arrangement is the disordered structure and is interpreted as a randomly occurring but well-defined local shift of the Fe-O chains in the Fe2O2+δ layers. By analyzing the electron energy-loss near-edge structure of the different building blocks in the Sr4Fe6O12+δ unit cell we find that the mobile holes in this mixed ionic-electronic conducting oxide are highly localized in the Fe2O2+δ layers, which are responsible for the oxide-ion conductivity. A possible link between disorder and oxygen-ion transport along the Fe2O2+δ layers is proposed by arguing that the disorder can effectively break the oxygen diffusion pathways. © 2013 American Chemical Society.

Beche A.,CEA Grenoble | Beche A.,University of Antwerp | Rouviere J.L.,CEA Grenoble | Barnes J.P.,CEA Grenoble | Cooper D.,CEA Grenoble
Ultramicroscopy | Year: 2013

Convergent beam electron diffraction (CBED), nano-beam electron diffraction (NBED or NBD), high resolution imaging (HRTEM and HRSTEM) and dark field electron holography (DFEH or HoloDark) are five TEM based techniques able to quantitatively measure strain at the nanometer scale. In order to demonstrate the advantages and disadvantages of each technique, two samples composed of epitaxial silicon-germanium layers embedded in a silicon matrix have been investigated. The five techniques are then compared in terms of strain precision and accuracy, spatial resolution, field of view, mapping abilities and ease of performance and analysis. © 2013 Elsevier B.V.

Leprieur F.,Montpellier University | Leprieur F.,French Natural History Museum | Tedesco P.A.,French Natural History Museum | Hugueny B.,French Natural History Museum | And 4 more authors.
Ecology Letters | Year: 2011

Here, we employ an additive partitioning framework to disentangle the contribution of spatial turnover and nestedness to beta diversity patterns in the global freshwater fish fauna. We find that spatial turnover and nestedness differ geographically in their contribution to freshwater fish beta diversity, a pattern that results from contrasting influences of Quaternary climate changes. Differences in fish faunas characterized by nestedness are greater in drainage basins that experienced larger amplitudes of Quaternary climate oscillations. Conversely, higher levels of spatial turnover are found in historically unglaciated drainage basins with high topographic relief, these having experienced greater Quaternary climate stability. Such an historical climate signature is not clearly detected when considering the overall level of beta diversity. Quantifying the relative roles of historical and ecological factors in explaining present-day patterns of beta diversity hence requires considering the different processes generating these patterns and not solely the overall level of beta diversity. © 2011 Blackwell Publishing Ltd/CNRS.

Sahin H.,Bilkent University | Sahin H.,University of Antwerp | Ciraci S.,Bilkent University
Journal of Physical Chemistry C | Year: 2012

We perform first-principles structure optimization, phonon frequency, and finite temperature molecular dynamics calculations based on density functional theory to study the interaction of chlorine atoms with graphene predicting the existence of possible chlorinated graphene derivatives. The bonding of a single chlorine atom is ionic through the transfer of charge from graphene to chlorine adatom and induces negligible local distortion in the underlying planar graphene. Different from hydrogen and fluorine adatoms, the migration of a single chlorine adatom on the surface of perfect graphene takes place almost without barrier. However, the decoration of one surface of graphene with Cl adatoms leading to various conformations cannot be sustained due to strong Cl-Cl interaction resulting in the desorption through the formation of Cl2 molecules. On the contrary, the fully chlorinated graphene, chlorographene CCl, where single chlorine atoms are bonded alternatingly to each carbon atom from different sides of graphene with sp3-type covalent bonds, is buckled. We found that this structure is stable and is a direct band gap semiconductor, whose band gap can be tuned by applied uniform strain. Calculated phonon dispersion relation and four Raman-active modes of chlorographene are discussed. © 2012 American Chemical Society.

Heylen L.,University of Antwerp
Ageing and Society | Year: 2010

Loneliness is often associated with old age, but many studies have shown that the relationship is not straightforward. This paper seeks a better understanding of the impact of social isolation on feelings of loneliness among older people, by building on the theoretical and actual distinction between social and emotional loneliness. Social loneliness refers to a lack of feelings of social integration; emotional loneliness emerges in the absence of an attachment figure. This paper focuses on social loneliness and has two aims, first to disentangle the direct and intermediate effects of both the number and the quality of social relationships on social loneliness in old age, and second to detect the groups at risk of social loneliness by identifying which personal features correspond with which relational deficits and therefore indirectly increase the risk on social loneliness. Data are analysed for a sample of 1,414 respondents aged 55 or more years drawn from the Panel Study of Belgian Households conducted in 2000. The results confirm that improved understanding is gained by decomposing the interrelation between age and other background features, on the one hand, and the social relational features, on the other, as indirect and direct predictors of social loneliness. Generally, this approach promotes a correct identification of the groups at risk of social loneliness in old age. Copyright © Cambridge University Press 2010.

Coenen S.,University of Antwerp
European Journal of General Practice | Year: 2012

Respiratory infections are still among the most common new diagnoses in primary care. The most frequent reason for encounter is acute cough. General practitioners have to make antibiotic prescribing decisions in a context of diagnostic uncertainty, patient preferences and antimicrobial resistance. There is a causal link between antimicrobial resistance and antibiotic prescribing in primary care. GRACE observational studies (www.grace-lrti.org), show that variation in clinical presentation does not explain the considerable variation in antibiotic prescribing in Europe for adults presenting in primary care with acute cough and that recovery is similar between those treated with any antibiotic, a particular antibiotic class, or no antibiotic. A GRACE randomized controlled trial (RCT) of the effect of antibiotics for acute cough has recruited more patients than all RCTs combined in the current Cochrane Review and will have the power to identify subgroups of patients who will (not) benefit from amoxicillin. Another multi-country GRACE RCT assessing the effect on antibiotic prescribing of largely web-based versions of successful interventions including a C-reactive protein point-of-care test, a communication skill training and an interactive patient booklet is awaited. Given potential long-term cost-effectiveness, the GRACE suite of observational and interventional studies are enhancing the evidence base for reducing diagnostic uncertainty and managing patient expectations in a patient-centred way to achieve greater evidence-based antibiotic prescribing that is likely to help containing antimicrobial resistance. © 2011 Informa Healthcare.

Wyndaele J.J.,University of Antwerp
Annals of Physical and Rehabilitation Medicine | Year: 2014

Clean intermittent self-catheterization (CISC) is considered the method of choice for treating urinary retention as of neurologic origin. Also, in multiple sclerosis (MS) the method is widely applied. Proper application needs sufficient hand function, possibility for proper positioning, sufficient sensation, cognitive function and as always the choice of the optimal material. The overall results are good. Specifically for MS patients more than average attention has to be given to training and follow-up in case of cognitive function impairment. Complications are acceptable with urinary tract infection having the highest incidence. MS being a progressive disease treatment possibly needs to be changed during follow-up. © 2014 Elsevier Masson SAS.

Temmerman S.,University of Antwerp | De Vries M.B.,Deltares | Bouma T.J.,Netherlands Institute for Sea Research
Global and Planetary Change | Year: 2012

Global climate change is expected to increase the risks of coastal flood disasters due to accelerating sea level rise and increasing intensity and frequency of storm surges. Coastal marsh vegetation is considered, on the one hand, to increase resistance to a landward propagating flood wave, such as a storm surge, and hence to protect against flood disasters. On the other hand, coastal marsh vegetation is dying off at several places around the world due to accelerating sea level rise. Here we present hydrodynamic model simulations of flood attenuation by a tidal marsh, with particular focus on the effects of spatial patterns of vegetation die-off. It is shown that a same percentage of marsh die-off but occurring as different spatial patterns of marsh break-up has largely different effects on flood attenuation. Patches of die-off that are directly connected to tidal channels have a much greater effect on increased landward flood propagation, while a same percentage of marsh die-off, but occurring at inner marsh locations disconnected from tidal channels, has only a minor effect. This implies that a random pattern of up to 50% of marsh die-off still provides a considerable flood attenuating effect. However with increasing percentage of random marsh die-off the flood attenuating effect decreases exponentially, since the chance for vegetation die-off occurring directly adjacent to tidal channels increases. This study demonstrates that tidal marsh die-off, which may increase with ongoing global change, is expected to have non-linear effects on reduced coastal protection against flood waves. © 2012 Elsevier B.V.

Banks P.B.,University of Sydney | Hughes N.K.,University of New South Wales | Hughes N.K.,University of Antwerp
Wildlife Research | Year: 2012

The black rat (Rattus rattus) is among the world's worst invasive species, having spread across the globe in close association with the spread of human settlement. It is the source of some of the worst diseases affecting humans and is thought to have had a devastating impact on native wildlife, especially in island ecosystems. Black rat is likely to have arrived in Australia with the first European settlers, making it among the first of many alien species to invade the continent, and it is now widespread. Yet, its impacts on local wildlife have largely been overlooked. Here, we review the potential for black rat impacts in Australia in terms of its role as a source of disease and threats to wildlife and humans. We first summarise the global evidence for black rat impacts as background to the potential threats it poses and then focus specifically on emerging evidence available for Australian systems. We found a significant gap in our understanding of the ecology of black rats and the ecological role that it plays in Australia. This is despite its role as a source of a diverse range of diseases affecting humans and wildlife and its actions as a predator and competitor of native wildlife in Australia and elsewhere. © CSIRO 2012.

Verdoolaege G.,Ghent University | Scheunders P.,University of Antwerp
International Journal of Computer Vision | Year: 2011

We consider the Rao geodesic distance (GD) based on the Fisher information as a similarity measure on the manifold of zero-mean multivariate generalized Gaussian distributions (MGGD). The MGGD is shown to be an adequate model for the heavy-tailed wavelet statistics in multicomponent images, such as color or multispectral images. We discuss the estimation of MGGD parameters using various methods. We apply the GD between MGGDs to color texture discrimination in several classification experiments, taking into account the correlation structure between the spectral bands in the wavelet domain. We compare the performance, both in terms of texture discrimination capability and computational load, of the GD and the Kullback-Leibler divergence (KLD). Likewise, both uni- and multivariate generalized Gaussian models are evaluated, characterized by a fixed or a variable shape parameter. The modeling of the interband correlation significantly improves classification efficiency, while the GD is shown to consistently outperform the KLD as a similarity measure. © 2011 Springer Science+Business Media, LLC.

Vlaar T.,VU University Amsterdam | Ruijter E.,VU University Amsterdam | Maes B.U.W.,University of Antwerp | Orru R.V.A.,VU University Amsterdam
Angewandte Chemie - International Edition | Year: 2013

Isocyanides have been important building blocks in organic synthesis since the discovery of the Ugi reaction and related isocyanide-based multicomponent reactions. In the past decade isocyanides have found a new application as versatile C1 building blocks in palladium catalysis. Palladium-catalyzed reactions involving isocyanide insertion offer a vast potential for the synthesis of nitrogen-containing fine chemicals. This Minireview discusses all the achievements in this emerging field. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Notteboom T.E.,University of Antwerp | Notteboom T.E.,Antwerp Maritime Academy
Journal of Transport Geography | Year: 2012

The Suez Canal plays a pivotal role in today's global container shipping network, in particularly in accommodating vessels sailing on the important Asia-Europe trade lane. This paper analyses to what extent and for which trade lanes the Cape route could develop into a competitive alternative to the Suez route. The market potential of the Cape route is analysed using a distance analysis, a transit time analysis and a generalized cost analysis for a large set of O/D relations. We compare vessel interlining via the port of Algeciras with interlining via the new port of Ngqura in South Africa. The results show that the Cape route has the potential to serve as an alternative to the Suez route on 11 trade lanes. A scenario and sensitivity analysis reveals that interlining via a hub near the Cape is expected to become more competitive due to a combination of higher Suez Canal transit fees, better vessel economics, higher bunker costs, slow steaming practices and subject to a more competitive terminal pricing strategy of southern African transhipment facilities. The expected emergence of the Cape route should be seen as the embodiment of a promising development of south-south trade volumes between Asia, Sub-Saharan Africa and South America. © 2012 Elsevier Ltd.

Mahmud T.,Transparency International Bangladesh | Prowse M.,University of Antwerp
Global Environmental Change | Year: 2012

This article seeks to draw possible lessons for adaptation programmes in Bangladesh by examining whether cyclone preparedness and relief interventions are subject to corrupt practices. Based on a random sample survey of 278 households, three focus-group discussions and seven key-informant interviews, the article investigates the nature and extent of corruption in pre- and post-disaster interventions in Khulna before and after Cyclone Aila in May 2009. Ninety nine percent of households reported losses from corrupt practices. Post-disaster interventions (such as food aid and public works schemes) suffered from greater levels, and worse types, of corruption than pre-disaster interventions (such as cyclone warning systems and disaster-preparedness training). Using an asset index created using principal component analysis, the article assesses how corruption affected wealth quartiles. Ultra-poor households were affected more by corruption in pre-disaster interventions, the wealthiest quartile more in certain post-disaster interventions, in particular public works and non-governmental interventions. These findings may hold lessons for attempts to increase resilience as current adaptation measures mirror some cyclone preparedness and relief efforts. © 2012 Elsevier Ltd.

De Bruyn P.,University of Antwerp
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011

Contemporary organizations are operating in a hypercompetitive environment, in which they are faced with challenges such as increasing complexity and increasing change in many or all of their aspects. As such, current organizations need to be more agile to keep up with the swiftly changing business environment. However, current development practices for information systems supporting these organizations appear to be insufficient to deal with these levels of changing complexity. Normalized Systems theory therefore proposes a theoretical framework that explains why current modular structures in information systems are intrinsically limited in terms of evolvability, as well as how modular structures can be built without these limitations, thus exhibiting evolvable modularity. The goal of the proposed Ph.D. research project is to develop a contribution to how evolvable modularity as a theoretical framework can be further extended from the technological level to the business level and as such support business processes, enterprise architectures and their supporting IT systems. The ultimate purpose will be to make organizations as a whole more agile by developing so-called normalized design patterns (domain models) on the business level in order to allow a more deterministic approach enabling the 'expanding' of enterprises. © 2011 Springer-Verlag.

Myin E.,University of Antwerp
Journal of Consciousness Studies | Year: 2011

Smell 'sensations' are among the most mysterious of conscious experiences and have been cited in defence of the thesis that the character of perceptual experience is independent of the physical events that seem to give rise to it. Here we review the scientific literature on olfaction, and we argue that olfaction has a distinctive profile in relation to the other modalities on four counts: in the physical nature of the stimulus, in the sensorimotor interactions that characterize its use, in the structure of its intramodal distinctions, and in the functional role that it plays in people's behaviour. We present two thought experiments in which we detail what would be involved in transforming sounds into smells, and also smells into colours. Through these thought experiments, we argue that the experiential character of smell derives precisely from the structural features of olfaction, and that an embodied account of olfactory phenomenology is called for. © Imprint Academic 2011.

Van Dongen S.,University of Antwerp | Gangestad S.W.,University of New Mexico
Evolution and Human Behavior | Year: 2011

Developmental instability (DI) reflects the inability of a developing organism to buffer its development against random perturbations, due either to frequent, large perturbations or to a poor buffering system. The primary measure used to assess DI experienced by an individual organism is fluctuating asymmetry (FA), asymmetry of bilateral features that are, on average in a population, symmetrical. A large literature on FA in humans in relation to measures of health and quality (close to 100 studies and nearly 300 individual effect size estimates) has accumulated. This paper presents the first quantitative meta-analysis of this literature. The mean effect size (scaled as Pearson r) was about 0.2. Effect sizes covaried negatively with sample size, consistent with effects of publication bias, the tendency for significant effects to be published. Conservative correction for this bias reduced the mean effect to about 0.1. Associations with FA underestimate effects of underlying DI due to imprecise measurement of the latter. A model-based best estimate of the mean effect of DI on outcomes is about 0.3, a theoretically meaningful, relatively large effect, albeit of moderate absolute size. The data are consistent, however, with a range of true effect sizes between 0.08 and 0.67, partly due to large study effects. Study-specific effect sizes in DI ranged between -0.2 and 1.0. A humbling and perhaps sobering conclusion is that, in spite of a large body of literature involving nearly 50 000 participants, we can only confidently state that there is on average a robust positive average effect size. An accurate estimate of that effect size was not possible, and between-study variation remained largely unexplained. We detected no robust variation across six broad categories of outcomes (health and disease, fetal outcomes, psychological maladaptation, reproduction, attractiveness and hormonal effects), though examination of narrower domains reveal some corrected effects close to 0.2 and others near zero. The meta-analysis suggests fruitful directions for future research and theory. © 2011 Elsevier Inc.

Adams F.,University of Antwerp
Talanta | Year: 2011

The significant role of analytical science in the field of chemistry was examined on the occasion of the International Year of Chemistry of 2011. Analytical instrumentation based on spectroscopy and other physical principles and analytical techniques has led to the advancements in the analytical chemistry. Development was based on two distinct parameters that include microelectronics and integrated circuit (IC) technology and information technology. The evolution of IC technology has led to the advancements in the performance parameters such as detection limits and spatial analytical potential. Various analytical techniques become increasingly dependent on IT infrastructure for instrument operation and, with time, increasingly complex calculations, for data management, spectral data handling, and image processing and statistical analysis of increasingly large data sets. There are many highly sophisticated analytical tools available for the characterization of inorganic and organic materials with a high structural complexity and heterogeneity.

Kunze A.,Ecole Polytechnique Federale de Lausanne | Giugliano M.,Ecole Polytechnique Federale de Lausanne | Giugliano M.,University of Antwerp | Valero A.,Ecole Polytechnique Federale de Lausanne | Renaud P.,Ecole Polytechnique Federale de Lausanne
Biomaterials | Year: 2011

Cortical neurons, in their native state, are organized in six different cell layers; and the thickness of the cell layer ranges from 0.12 mm to 0.4 mm. The structure of cell layers plays an important role in neurodegenerative diseases or corticogenesis. We developed a 3D microfluidic device for creating physiologically realistic, micrometer scaled neural cell layers. Using this device, we demonstrated that (1) agarose-alginate mixture can be gelled thermally, thus an excellent candidate for forming multi-layered scaffolds for micropatterning embedded cells; (2) primary cortical neurons were cultured successfully for up to three weeks in the micropatterned multi-layered scaffold; (3) B27 concentration gradient enhanced neurite outgrowth. In addition, this device is compatible with optical microscopy, the dynamic process of neural growth can be imaged, and density and number of neurites can be quantified. This device can potentially be used for drug development, as well as research in basic neural biology. © 2010 Elsevier Ltd.

Botha M.H.,Stellenbosch University | Dochez C.,University of Antwerp
Vaccine | Year: 2012

South Africa has a high incidence of cervical cancer, with an age-standardised rate of approximately 27 per 100,000. In 2000, South Africa launched a national screening programme for cervical cancer prevention, offering three Papanicolaou smears per lifetime starting after the age of 30 with 10-year intervals. However, in the public sector, this national screening programme has not been implemented widely. Vaccination would offer the best primary prevention. Currently there are two HPV vaccines registered in South Africa: the bivalent vaccine Cervarix™, containing VLP antigens for oncogenic HPV types 16 and 18; and the quadrivalent vaccine Gardasil™, containing VLP antigens for HPV types 16 and 18, as well as non-oncogenic HPV types 6 and 11, which are the most common types causing genital warts. The vaccines are recommended for prophylactic use, and should ideally be given before exposure to HPV, which is before sexual debut, to girls aged 11-12 years. Possible routes for delivering the HPV vaccine could be either the routine EPI programme at the age of 12 years when dT is being administered, or through the school system, e.g. to girls attending grade 5 or 6. © 2012 Elsevier Ltd.

Vanham G.,Antwerp Institute of Tropical Medicine | Vanham G.,University of Antwerp | Van Gulck E.,Antwerp Institute of Tropical Medicine | Van Gulck E.,Present Address Community Of Research Excellence And Advanced Technology Create
Retrovirology | Year: 2012

Immunotherapy aims to assist the natural immune system in achieving control over viral infection. Various immunotherapy formats have been evaluated in either therapy-naive or therapy-experienced HIV-infected patients over the last 20 years. These formats included non-antigen specific strategies such as cytokines that stimulate immunity or suppress the viral replication, as well as antibodies that block negative regulatory pathways. A number of HIV-specific therapeutic vaccinations have also been proposed, using in vivo injection of inactivated virus, plasmid DNA encoding HIV antigens, or recombinant viral vectors containing HIV genes. A specific format of therapeutic vaccines consists of ex vivo loading of autologous dendritic cells with one of the above mentioned antigenic formats or mRNA encoding HIV antigens.This review provides an extensive overview of the background and rationale of these different therapeutic attempts and discusses the results of trials in the SIV macaque model and in patients. To date success has been limited, which could be explained by insufficient quality or strength of the induced immune responses, incomplete coverage of HIV variability and/or inappropriate immune activation, with ensuing increased susceptibility of target cells.Future attempts at therapeutic vaccination should ideally be performed under the protection of highly active antiretroviral drugs in patients with a recovered immune system. Risks for immune escape should be limited by a better coverage of the HIV variability, using either conserved or mosaic sequences. Appropriate molecular adjuvants should be included to enhance the quality and strength of the responses, without inducing inappropriate immune activation. Finally, to achieve a long-lasting effect on viral control (i.e. a " functional cure" ) it is likely that these immune interventions should be combined with anti-latency drugs and/or gene therapy. © 2012 Vanham and Van Gulck; licensee BioMed Central Ltd.

Torres P.A.U.,Service de Nephrologie et Dialyse | De Broe M.,University of Antwerp
Kidney International | Year: 2012

Renal function impairment goes along with a disturbed calcium, phosphate, and vitamin D metabolism, resulting in secondary hyperparathyroidism (sHPT). These mineral metabolism disturbances are associated with soft tissue calcifications, particularly arteries, cardiac valves, and myocardium, ultimately associated with increased risk of mortality in patients with chronic kidney disease (CKD). sHPT may lead to cardiovascular calcifications by other mechanisms including an impaired effect of parathyroid hormone (PTH), and a decreased calcium-sensing receptor (CaR) expression on cardiovascular structures. PTH may play a direct role on vascular calcifications through activation of a receptor, the type-1 PTH/PTHrP receptor, normally attributed to PTH-related peptide (PTHrP). The CaR in vascular cells may also play a role on vascular mineralization as suggested by its extremely reduced expression in atherosclerotic calcified human arteries. Calcimimetic compounds increasing the CaR sensitivity to extracellular calcium efficiently reduce serum PTH, calcium, and phosphate in dialysis patients with sHPT. They upregulate the CaR in vascular cells and attenuate vascular mineralization in uremic states. In this article, the pathophysiological mechanisms associated with cardiovascular calcifications in case of sHPT, the impact of medical and surgical correction of sHPT, the biology of the CaR in vascular structures and its function in CKD state, and finally the role played by the CaR and its modulation by the calcimimetics on uremic-related cardiovascular calcifications are reviewed. © 2012 International Society of Nephrology.

Boudiny K.,University of Antwerp
Ageing and Society | Year: 2013

'Active ageing' is a topic of increasing attention in scientific and policy discussions on ageing, yet there is no consensus on its actual meaning. The current paper proposes a detailed classification of various definitions that have been used since its introduction. These definitions are subjected to critical investigation, and subtle differences with regard to such terms as 'healthy ageing' and 'productive ageing' are clarified. Bearing the hazards of previous definitions in mind, a comprehensive strategy is initiated. Given that earlier definitions have tended to exclude frail older adults, this strategy pays particular attention to the translation of the active-ageing concept to situations of dependency by centring on three key principles: fostering adaptability, supporting the maintenance of emotionally close relationships and removing structural barriers related to age or dependency. Copyright © 2012 Cambridge University Press.

Brauers W.K.M.,University of Antwerp | Kracka M.,Vilnius Gediminas Technical University | Zavadskas E.K.,Vilnius Gediminas Technical University
Journal of Civil Engineering and Management | Year: 2012

This paper presents the process of effective selection of building elements for renovation important for energy saving in buildings. A large part of energy is lost in non-effective buildings. Therefore, in renovation of buildings, it is important to select effective structural improvements. Building insulation could not only save energy but also time, money and materials, which means that different objectives expressed in different units have to be fulfilled. Although different methods exist for the application of Multi Objective Optimisation, MULTIMOORA, which is composed of three sub-methods - Ratio System, Reference Point Method that uses ratios from the ratio system, and the Full Multiplicative Form - was preferred. Consequently, different solutions for building envelope renovation were ranked by MULTIMOORA as applied for masonry buildings from the Soviet period. © 2012 Copyright Vilnius Gediminas Technical University (VGTU) Press Technika.

Peeters T.,University of Antwerp
International Journal of Industrial Organization | Year: 2012

Because sports clubs jointly produce sports competitions, the quality of these competitions is determined by the talent investments of all clubs involved in them. Operating as legal cartels, sports leagues may try to coordinate talent investments in order to maximize profitability. In this paper I analyze the ways in which sharing mechanisms for collective media revenues may serve this goal when demand comes from differentiated consumers. Performance-based sharing turns out to be an inefficient sharing mechanism for the league. Such inefficient cartel behavior may be rationalized as the result of bargaining with asymmetric outside options. © 2011 Elsevier B.V.

Bodi M.B.,University of Antwerp | Bodi M.B.,University of Valencia | Martin D.A.,U.S. Geological Survey | Balfour V.N.,University of Montana | And 5 more authors.
Earth-Science Reviews | Year: 2014

Fire transforms fuels (i.e. biomass, necromass, soil organic matter) into materials with different chemical and physical properties. One of these materials is ash, which is the particulate residue remaining or deposited on the ground that consists of mineral materials and charred organic components. The quantity and characteristics of ash produced during a wildland fire depend mainly on (1) the total burned fuel (i.e. fuel load), (2) fuel type and (3) its combustion completeness. For a given fuel load and type, a higher combustion completeness will reduce the ash organic carbon content, increasing the relative mineral content, and hence reducing total mass of ash produced. The homogeneity and thickness of the ash layer can vary substantially in space and time and reported average thicknesses range from close to 0 to 50. mm. Ash is a highly mobile material that, after its deposition, may be incorporated into the soil profile, redistributed or removed from a burned site within days or weeks by wind and water erosion to surface depressions, footslopes, streams, lakes, reservoirs and, potentially, into marine deposits.Research on the composition, properties and effects of ash on the burned ecosystem has been conducted on material collected in the field after wildland and prescribed fires as well as on material produced in the laboratory. At low combustion completeness (typically T<450°C), ash is organic-rich, with organic carbon as the main component. At high combustion completeness (T>450°C), most organic carbon is volatized and the remaining mineral ash has elevated pH when in solution. It is composed mainly of calcium, magnesium, sodium, potassium, silicon and phosphorous in the form of inorganic carbonates, whereas at T>580°C the most common forms are oxides. Ash produced under lower combustion completeness is usually darker, coarser, and less dense and has a higher saturated hydraulic conductivity than ash with higher combustion completeness, although physical reactions with CO2 and when moistened produce further changes in ash characteristics.As a new material present after a wildland fire, ash can have profound effects on ecosystems. It affects biogeochemical cycles, including the C cycle, not only within the burned area, but also globally. Ash incorporated into the soil increases temporarily soil pH and nutrient pools and changes physical properties such as albedo, soil texture and hydraulic properties including water repellency. Ash modifies soil hydrologic behavior by creating a two-layer system: the soil and the ash layer, which can function in different ways depending on (1) ash depth and type, (2) soil type and (3) rainfall characteristics. Key parameters are the ash's water holding capacity, hydraulic conductivity and its potential to clog soil pores. Runoff from burned areas carries soluble nutrients contained in ash, which can lead to problems for potable water supplies. Ash deposition also stimulates soil microbial activity and vegetation growth.Further work is needed to (1) standardize methods for investigating ash and its effects on the ecosystem, (2) characterize ash properties for specific ecosystems and wildland fire types, (3) determine the effects of ash on human and ecosystem health, especially when transported by wind or water, (4) investigate ash's controls on water and soil losses at slope and catchment scales, (5) examine its role in the C cycle, and (6) study its redistribution and fate in the environment. © 2014 Elsevier B.V.

Dirtu A.C.,University of Antwerp | Covaci A.,University of Antwerp | Dirtu A.C.,Al. I. Cuza University | Abdallah M.,Assiut University
TrAC - Trends in Analytical Chemistry | Year: 2013

This review aims to highlight the recent advances and methodological improvements in sample-preparation techniques applied to the analysis of different brominated flame retardants (BFRs) and other brominated chemicals [e.g., naturally-occurring brominated compounds (BCs)]. The principal literature sources are research articles published since 2010. The main selection criteria involved the successful development and application of analytical methods for determination of the target BCs in various matrices. In particular, we discuss sample extraction and clean-up with emphasis on recent technical developments and new strategies for sample preparation.We give priority to extraction techniques using advanced instrumentation to achieve outstanding advantages over traditional extraction methods. We discuss clean-up and fractionation methods for various types of biotic and abiotic samples. We investigated a few new techniques (e.g., solid-phase micro-extraction or pressurized-liquid extraction) for their ability to combine extraction and clean-up steps. Finally, we identify current research gaps associated with extraction and clean-up methodology for BFRs and propose future research perspectives. © 2012 Elsevier Ltd.

Derycke S.,Ghent University | Backeljau T.,Royal Belgian Institute Of Natural Sciences | Backeljau T.,University of Antwerp | Moens T.,Ghent University
Frontiers in Zoology | Year: 2013

Dispersal and gene flow determine connectivity among populations, and can be studied through population genetics and phylogeography. We here review the results of such a framework for free-living marine nematodes. Although field experiments have illustrated substantial dispersal in nematodes at ecological time scales, analysis of the genetic diversity illustrated the importance of priority effects, founder effects and genetic bottlenecks for population structuring between patches <1 km apart. In contrast, only little genetic structuring was observed within an estuary (<50 km), indicating that these small scale fluctuations in genetic differentiation are stabilized over deeper time scales through extensive gene flow. Interestingly, nematode species with contrasting life histories (extreme colonizers vs persisters) or with different habitat preferences (algae vs sediment) show similar, low genetic structuring. Finally, historical events have shaped the genetic pattern of marine nematodes and show that gene flow is restricted at large geographical scales. We also discuss the presence of substantial cryptic diversity in marine nematodes, and end with highlighting future important steps to further unravel nematode evolution and diversity. © 2013 Derycke et al.; licensee BioMed Central Ltd.

Purpose: Increasing mobility demands and growing industrial tissue come with a burden for the environment. Inventive solutions are necessary to address this challenge. This paper compares the environmental impact of two alternative container transportation methods over a 25-year time period for a specific trajectory and transport volume in the Antwerp harbor. One is a pipeline concept; the other a road concept to link the Deurganck dock with the right bank in order to transport 2 million containers per year. Materials and methods: With a detailed bill of material and the use of the Ecolizer method, a Monte Carlo simulation was performed to calculate the environmental impact in terms of ECOPOINTS on a life cycle perspective. Results and discussion: The results remark that in 94% of the cases the pipeline concept has less than half of the environmental impact of the road concept. Furthermore, in both concepts the operational phase is the largest contributor to the total environmental impact. Conclusions: The pipeline concept results suggest a much lower total environmental impact over a road concept if a large enough volume of containers can effectively be transported. Some considerations have to be given to the used electricity mix, the applied impact assessment method and the case specificities. © Springer-Verlag 2011.

Adams F.,University of Antwerp
Journal of Analytical Atomic Spectrometry | Year: 2013

Spectroscopic analytical methodologies are reviewed from a personal perspective, with special emphasis on plasma analytical techniques and imaging analysis. Selected examples from the laboratory experience of the author over his career illustrate the constantly increasing sophistication (sensitivity, specificity, spatial discrimination...) of analytical techniques over the last 4-5 decades, with an unfaltering evolution with ongoing scientific and technological progress, and, at particular occasions, unexpected and abrupt swerves in this uninterrupted development process. This journal is © 2013 The Royal Society of Chemistry.

Penuelas J.,University of Barcelona | Sardans J.,University of Barcelona | Rivas-ubach A.,University of Barcelona | Janssens I.A.,University of Antwerp
Global Change Biology | Year: 2012

Human-induced carbon and nitrogen fertilization are generating a strong imbalance with P. This imbalance confers an increasingly important role to P availability and N: P ratio in the Earth's life system, affecting carbon sequestration potential and the structure, function and evolution of the Earth's ecosystems. © 2011 Blackwell Publishing Ltd.

De Keyzer T.H.,University of Antwerp
Bulletin de la Société belge d'ophtalmologie | Year: 2011

To report a family diagnosed with Stickler syndrome. To emphasize that early recognition of patients with Stickler syndrome could improve the visual outcome. Case report. A 14 year old girl of Mahgrebian origin presented with a longstanding subtotal RRD in the right eye. Subsequently 6 family members in 3 generations have been identified with the same COL2A1 mutation. 4 eyes lost perception of light and 1 eye was enucleated. Stickler syndrome is the commonest inherited cause of rhegmatogenous retinal detachment (RRD). These tend to be complex and to occur at young age, frequently affecting both eyes. Other ocular features consist of high myopia, optically empty vitreous cavity, posterior radial paravascular lattice-type degeneration, cataract and glaucoma. Non-ocular findings include midface hypoplasia, musculoskeletal changes and hearing loss. In severe cases the disorder will readily be suspected. In mildly affected patients, clinical diagnosis can be quite difficult. Therefore, all family members of a Stickler patient should be offered molecular genetic testing. Stickler patients benefit from a multidisciplinary approach, including audiologic examination. They should be informed about the symptoms associated with retinal tears and retinal detachment and have priviliged access to the ophthalmic care unit. In case of RRD, vitrectomy is the preferred surgery. Prophylaxis of RRD in Stickler syndrome patients consisting of a 360 degrees peripheral cryotherapy or photocoagulation has been proposed. Practical guidelines for follow up or thresholds for initiating treatment have not been formulated. Stickler syndrome remains under-diagnosed. Hightened awareness of Stickler syndrome could improve visual outcome in affected individuals and makes genetic counseling possible

Yan E.,Drexel University | Guns R.,University of Antwerp
Journal of Informetrics | Year: 2014

This study examines collaboration dynamics with the goal to predict and recommend collaborations starting from the current topology. Author-, institution-, and country-level collaboration networks are constructed using a ten-year data set on library and information science publications. Different statistical approaches are applied to these collaboration networks. The study shows that, for the employed data set in particular, higher-level collaboration networks (i.e., country-level collaboration networks) tend to yield more accurate prediction outcomes than lower-level ones (i.e., institution- and author-level collaboration networks). Based on the recommended collaborations of the data set, this study finds that neighbor-information-based approaches are more clustered on a 2-D multidimensional scaling map than topology-based ones. Limitations of the applied approaches on sparse collaboration networks are also discussed. © 2014 Elsevier Ltd.

Van Houdt B.,University of Antwerp | Van Leeuwaarden J.S.H.,TU Eindhoven
INFORMS Journal on Computing | Year: 2011

In applying matrix-analytic methods to M/G/1-type and tree-like quasi-birth-death (QBD) Markov chains, it is crucial to determine the solution to a (set of) nonlinear matrix equation(s). This is usually done via iterative methods. We consider the highly structured subclass of triangular M/G/1-type and tree-like QBD Markov chains that allows for an efficient direct solution of the matrix equation. © 2011 INFORMS.

Neek-Amal M.,University of Tehran | Peeters F.M.,University of Antwerp
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

Mechanical stiffness of monolayer graphene with randomly distributed vacancies is studied using molecular-dynamics simulation and elasticity theory. Nanoindentation is used to obtain Young's modulus and the effective spring constant which decrease linearly with the percentage of vacancies. The load and unload curves are the same and the breaking force and breaking points depend on the percentage of vacancies. Fracture may appear near the boundaries. We introduce a simple method to make the system vibrate by pulling up the atomic force microscopy tip from the center of the clamped circular monolayer graphene which then starts to vibrate. © 2010 The American Physical Society.

Djomo S.N.,University of Antwerp | Djomo S.N.,Riga Technical University | Blumberga D.,Riga Technical University
Bioresource Technology | Year: 2011

A life cycle assessment was performed to quantify and compare the energetic and environmental performances of hydrogen from wheat straw (WS-H2), sweet sorghum stalk (SSS-H2), and steam potato peels (SPP-H2). Inventory data were derived from a pilot plant. Impacts were assessed using the impact 2002+ method. When co-product was not considered, the greenhouse gas (GHG) emissions were 5.60kg CO2eq kg-1H2 for WS-H2, 5.32kg CO2eq kg-1H2 for SSS-H2, and 5.18kg CO2eq kg-1H2 for SPP-H2. BioH2 pathways reduced GHG emissions by 52-56% compared to diesel and by 54-57% compared to steam methane reforming production of H2. The energy ratios (ER) were also comparable: 1.08 for WS-H2, 1.14 for SSS-H2 and 1.17 for SPP-H2. A shift from SPP-H2 to WS-H2 would therefore not affect the ER and GHG emissions of these BioH2 pathways. When co-product was considered, a shift from SPP-H2 to WS-H2 or SSS-H2 decreased the ER, while increasing the GHG emissions significantly. Co-product yield should be considered when selecting BioH2 feedstocks. © 2010 Elsevier Ltd.

Bosmans J.,University of Antwerp | Bleiziffer S.,TU Munich | Gerckens U.,Gemeinschaftskrankenhaus | Wenaweser P.,University of Bern | And 3 more authors.
Journal of the American College of Cardiology | Year: 2015

Background Transcatheter aortic valve replacement (TAVR) enables treatment of high-risk patients with symptomatic aortic stenosis without open-heart surgery; however, the benefits are mitigated by the potential for neurological events. Objectives This study sought to determine the timing and causes of clinically relevant neurological events after self-expandable TAVR. Methods We enrolled 1,015 patients, of whom 996 underwent TAVR with a self-expandable system at 44 TAVR-experienced centers in Europe, Colombia, and Israel. Neurological events were evaluated for 3 distinct time periods: periprocedural (0 to 1 days post TAVR); early (2 to 30 days); and late (31 to 730 days). In this real-world study, neurological events were first referred to the site neurologist and then reviewed by an independent neurologist. Results The overall stroke rate was 1.4% through the first day post-procedure, 3.0% at 30 days, and 5.6% at 2 years. There were no significant predictors of periprocedural stroke or stroke/transient ischemic attack (TIA) combined. Significant predictors of early stroke were acute kidney injury (p = 0.03), major vascular complication (p = 0.04), and female sex (p = 0.04). For stroke/TIA combined, prior atrial fibrillation (p = 0.03) and major vascular complication (p = 0.009) were predictive. Coronary artery bypass graft surgery was the only significant predictor of late stroke (p = 0.007) or late stroke/TIA (p = 0.06). Conclusions Treatment of high-risk patients with aortic stenosis using a self-expandable system was associated with a low stroke rate at short- and long-term follow-up. Multivariable predictors of clinically relevant neurological events differed on the basis of the timing after TAVR. (CoreValve Advance International Post Market Study; NCT01074658) © 2015 American College of Cardiology Foundation.

Sadowska A.M.,University of Antwerp
Therapeutic Advances in Respiratory Disease | Year: 2012

To develop an efficient therapy for chronic obstructive pulmonary disease (COPD), N-acetylcysteine (NAC) has been tested as a medication that can suppress various pathogenic processes in this disease. NAC is a thiol compound, which provides sulfhydryl groups. NAC can act as a precursor of reduced glutathione and as a direct reactive oxygen species scavenger, hence regulating the redox status in the cells. In this way NAC can interfere with several signaling pathways that play a role in regulating apoptosis, angiogenesis, cell growth and inflammatory response. Mucus hypersecretion has been reported in COPD and in other respiratory conditions. Two pathological processes have been described to play an important role in COPD, namely oxidative stress and inflammation. Both of these processes can induce mucin gene expression leading to mucin production. NAC, therefore, may influence mucin expression by acting on oxidative stress and inflammation, and play a role as a mucolytic agent. In this review we focus on the mucolysis of NAC in the management of COPD. © The Author(s), 2012.

De Winter B.Y.,University of Antwerp
Biochimica et Biophysica Acta - Molecular Basis of Disease | Year: 2012

Mast cells may be regarded as prototypes of innate immune cells that can be controlled by neuronal mediators. Their activation has been implicated in many types of neuro-inflammatory responses, and related disturbances of gut motility, via direct or indirect mechanisms that involve several mechanisms relevant to disease pathogenesis such as changes in epithelial barrier function or activation of adaptive or innate immune responses. Here we review the evidence for the involvement of mast cells in the inflammation of the bowel wall caused by bowel manipulation that leads to motility disturbances such as postoperative gastroparesis and ileus. Also in IBD there is substantial evidence for the involvement of mast cells and a mast cell-mediated neuroimmune interaction showing an increased number and an increased degranulation of mast cells. We discuss the potential of mast cell inhibition as a bona fide drug target to relief postoperative ileus. Further research on mast cell-related therapy either by stabilizing the mast cells or by blocking specific mast cell mediators as adjunctive therapy in IBD is encouraged, bearing in mind that several drugs currently used in the treatment of IBD possess properties affecting mast cell activities. This article is part of a Special Issue entitled: Mast cells in inflammation. © 2011.

Up to 30% of the adult population experiences tinnitus at some point in life. The aim of the present study was to validate the Mini-Tinnitus Questionnaire (TQ) in a Dutch-speaking population for measuring tinnitus-related distress and compare it with the extended version normally used in clinical practice and research. We assessed 181 patients at the Tinnitus Research Initiative clinic of Antwerp University Hospital. Twelve items from the TQ chosen by Hiller and Goebel based on the optimal combination of high item correlation, reliability, and sensitivity were selected and correlated to the different subscale and global scores of the TQ. Internal consistency was evaluated using Cronbach's alpha coefficient, and the Guttman split-half coefficient was used to confirm reliability. Correlation to the global TQ score was .93, internal consistency was .87, and reliability was .89. This study further revealed that the Mini-TQ correlates better with the different subscales of the TQ in the Dutch-speaking population. The convergence validity was confirmed, ensuring that this new instrument measures distress. In addition, the norms suggested by Hiller and Goebel were verified and established. Based on these results, the Mini-TQ is recommended as a valid instrument for evaluating tinnitus-related distress in Dutch-speaking populations for a compact, quick, and economical assessment.

A previous study among Antwerp college and university students showed that more male (10.2%-11.1%) than female (1.8%-6.2%) students are at risk for problematic alcohol use. The current literature shows promising results in terms of feasibility and effectiveness for the use of brief electronic interventions to address this health problem in college and university students. We evaluated this type of intervention and cite existing literature on the topic. To develop a website, www.eentjeteveel.be, to motivate college and university students with problematic alcohol use to reduce alcohol consumption and increase their willingness to seek help. The website contained a questionnaire (Alcohol Use Disorders Identification Test [AUDIT]) for students to test their alcohol use. According to their answers, the students immediately received personalized feedback (personal AUDIT score and additional information on risks associated with alcohol use) and a suggestion for further action. Afterward, students could send an email to a student counselor for questions, guidance, or advice. To obtain in-depth qualitative information on the opinions and experiences of students, we held 5 focus group discussions. The topics were publicity, experiences, impressions, and effects of the website. We analyzed the quantitative results of the online test in SPSS 15.0. More than 3500 students visited www.eentjeteveel.be; over half were men (55.0%). A total of 34 students participated in the focus group discussions. The mixture of quantitative and qualitative methods to evaluate the intervention allowed a thorough analysis and provided complementary results. The intervention was well received by the student population. However, some minor aspects should be reconsidered, such as website publicity and providing students with options that were added after intermediate evaluation. The intervention increased the motivation of students to think about their alcohol use but could not stimulate them to change their behavior. The website attracted relatively more male than female students and more students in the high-risk group than in the low-risk group. The high-risk group was more inclined to seek advice or guidance (23/400, 6%; χ(2) (2 = 32.4), P < .001) than the low-risk group (34/1714, 2%; χ(2) (2 = 32.4), P < .001). We gained unique insight into students' experiences, opinions, and perceptions with regard to the intervention. The results show that the intervention was positively received in the population, and the willingness to seek help was increased. However, real behavior change needs further research. The results of this study can assist health providers and researchers in better understanding college and university students' perceptions of eHealth initiatives.

Notteboom T.,University of Antwerp | Notteboom T.,Antwerp Maritime Academy | De Langen P.,TU Eindhoven | Jacobs W.,University Utrecht
Journal of Transport Geography | Year: 2013

This paper deals with path dependence in seaport governance. A central notion in this respect is lock-in. Economic geographers have recently started to reconsider the deterministic perspective on lock-in and developed the concept of institutional plasticity. Such plasticity is the result of actions of actors to purposefully 'recombine and convert or reinterpret institutions for their new objectives or transfer institutions to different contexts' (Strambach, 2010). This concept is applied to seaports, where so far, path dependence and lock-in have not been studied in detail. Our main conclusion is that a process of institutional stretching takes place when port authorities see a need to develop new capabilities and activities. In this process new layers are added to existing arrangements, gradually leading to a formalised governance reform but without breaking out of the existing path of development. © 2012 Elsevier Ltd.

Soens T.,University of Antwerp
Environment and History | Year: 2013

Starting in the later Middle Ages, the coastal wetlands along the southern North Sea area were increasingly hit by a series of catastrophic storm surges. Deeply rooted in the collective memory of coastal society, these flood disasters are mostly discussed as products of meteorological disturbances, environmental vulnerability or technological failure. In this article, an alternative reading is proposed, drawing attention to massive distortions in the social allocation of flood protection in the later Middle Ages, which help to explain the increased frequency of storm disasters. Building on Amartya Sen's original entitlement approach, it is argued that the right of coastal peasants to flood security often witnessed severe setbacks preceding many flood disasters, caused by adverse economic conditions, but also by an increasing violation of their entitlement to flood protection mainly by non-peasant groups, backed by an expanding state power. © 2013 The White Horse Press.

In Europe, a comparable scope of training in GP can be observed especially in the field of knowledge. This feasibility study determines if a knowledge test is suitable in the context of a neighboring country. A Dutch knowledge multiple choice test was used after validation of its content in Flanders (Belgium) in the academic year 2010-2011. Satisfaction with the test format was assessed. The test was taken by general practice trainees and trainers. Group scores of trainees in year 1, 2 and 3 and their trainers were compared to Dutch participants as a control group. 80 percent of the items in the Dutch test were transferable to Flanders (Belgium). Flemish participants (Belgium) liked the test format. The scores of all Belgian participants groups were lower than the Dutch participants. The results among 1278 participants show that the use of the Dutch knowledge multiple-choice test is feasible in a neighboring country. At present, the individual scores can not be used for high stake decisions for trainees in Flanders (Belgium). If countries collaborate in the area of assessing GPs trainees, there would be an economical benefit due to increased efficiency. It would also lead to greater international integration of the discipline.

Langguth B.,University of Regensburg | De Ridder D.,University of Antwerp
Handbook of Clinical Neurology | Year: 2013

Tinnitus is a common disorder and traditional treatment approaches such as medication, active or passive sound enhancement, and cognitive behavioral therapy have limited efficacy. Thus, there is an urgent need for more effective treatment approaches. Functional imaging studies in patients with tinnitus have revealed alterations in neuronal activity of central auditory pathways, probably resulting as a consequence of sensory deafferentation. However, nonauditory brain areas are also involved. These nonauditory brain areas might represent both an "awareness" network involved in the conscious perception of the tinnitus signal as well as areas related to a nontinnitus-specific distress network consisting of the anterior cingulate cortex, anterior insula, and amygdala. Moreover, memory mechanisms involving the hippocampus and the parahippocampal region may play a role in the persistence of the awareness of the phantom percept, as well as in the reinforcement of the associated distress. All of these networks represent potential targets for treatment via pharmacological treatment or noninvasive and invasive brain stimulation. Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive method of applying electromagnetic fields to the brain that can induce alterations of neuronal activity that outlast the stimulation period. Single sessions of rTMS over the temporal or temporoparietal cortex have been successful in transiently reducing tinnitus perception. Repeated sessions of rTMS have resulted in tinnitus relief in a subgroup of patients, lasting from several days to several months. However, effect sizes of rTMS in the treatment of tinnitus are only moderate, and interindividual variability is high. Larger and longer lasting effects have been observed with direct electrical stimulation of the auditory cortex via implanted epidural electrodes. Transcranial direct current stimulation (tDCS) has also shown potential for the treatment of tinnitus. Both auditory and frontal tDCS have shown tinnitus reduction in a subgroup of patients. In spite of the promising results of the different brain stimulation approaches, further research is needed before these techniques can be recommended for routine clinical use. © 2013 Elsevier B.V.

Kirsanova M.A.,Moscow State University | Olenev A.V.,Moscow State University | Abakumov A.M.,University of Antwerp | Bykov M.A.,Moscow State University | Shevelkov A.V.,Moscow State University
Angewandte Chemie - International Edition | Year: 2011

Now they are 10! The title compound displays a new type of crystal structure and is labeled clathrate X according to the general classification of clathrate structures. In contrast to typical clathrates, this compound has three-coordinate atoms within the framework and combines distorted 24-vertex polyhedra (see picture, green) centered around tellurium guest atoms with very irregular 10-vertex polyhedra around sulfur atoms (yellow). (Figure Presented). © 2011 Wiley-VCH Verlag GmbH & Co. KGaA.

Kelly R.,Medical Research Council | Zoubiane G.,Medical Research Council | Walsh D.,Medical Research Council | Ward R.,Medical Research Council | Goossens H.,University of Antwerp
The Lancet Infectious Diseases | Year: 2016

Background: Antibacterial resistant infections are rising continuously, resulting in increased morbidity and mortality worldwide. With no new antibiotic classes entering the market and the possibility of returning to the pre-antibiotic era, the Joint Programming Initiative on Antimicrobial Resistance (JPIAMR) was established to address this problem. We aimed to quantify the scale and scope of publicly funded antibacterial resistance research across JPIAMR countries and at the European Union (EU) level to identify gaps and future opportunities. Methods: We did a systematic observational analysis examining antibacterial resistance research funding. Databases of funding organisations across 19 countries and at EU level were systematically searched for publicly funded antibacterial resistance research from Jan 1, 2007, to Dec 31, 2013. We categorised studies on the basis of the JPIAMR strategic research agenda's six priority topics (therapeutics, diagnostics, surveillance, transmission, environment, and interventions) and did an observational analysis. Only research funded by public funding bodies was collected and no private organisations were contacted for their investments. Projects in basic, applied, and clinical research, including epidemiological, public health, and veterinary research and trials were identified using keyword searches by organisations, and inclusion criteria were based on the JPIAMR strategic research agenda's six priority topics, using project titles and abstracts as filters. Findings: We identified 1243 antibacterial resistance research projects, with a total public investment of €1·3 billion across 19 countries and at EU level, including public investment in the Innovative Medicines Initiative. Of the total amount invested in antibacterial resistance research across the time period, €646·6 million (49·5%) was invested at the national level and €659·2 million (50·5%) at the EU level. When projects were classified under the six priority topics we found that 763 (63%) of 1208 projects funded at national level were within the area of therapeutics, versus 185 (15%) in transmission, 131 (11%) in diagnostics, 53 (4%) in interventions, and only 37 (3%) in environment and 39 (3%) in surveillance. Interpretation: This was the first systematic analysis of research funding of antibacterial resistance of this scale and scope, which relied on the availability and accuracy of data from organisations included. Large variation was seen between countries both in terms of number of projects and associated investment and across the six priority topics. To determine the future direction of JPIAMR countries a clear picture of the funding landscape across Europe and Canada is needed. Countries should work together to increase the effect of research funding by strengthening national and international coordination and collaborations, harmonising research activities, and collectively pooling resources to fund multidisciplinary projects. The JPIAMR have developed a publicly available database to document the antibacterial resistance research collected and can be used as a baseline to analyse funding from 2014 onwards. Funding: JPIAMR and the European Commission. © 2016 Kelly et al. Open Access article distributed under the terms of CC BY.

Scalise E.,Catholic University of Leuven | Houssa M.,Catholic University of Leuven | Pourtois G.,IMEC | Pourtois G.,University of Antwerp | And 3 more authors.
Nano Research | Year: 2013

The structural and vibrational properties of two-dimensional hexagonal silicon (silicene) and germanium (germanene) are investigated by means of first-principles calculations. It is predict that the silicene (germanene) structure with a small buckling of 0. 44 Å (0. 7 Å) and bond lengths of 2. 28 Å (2. 44 Å) is energetically the most favorable, and it does not exhibit imaginary phonon mode. The calculated non-resonance Raman spectra of silicene is characterized by a main peak at about 575 cm-1, namely the G-like peak. For germanene, the highest peak is at about 290 cm-1. Extensive calculations on armchair silicene nanoribbons and armchair germanene nanoribbons are also performed, with and without hydrogenation of the edges. The studies reveal other Raman peaks mainly distributed at lower frequencies than the G-like peak which could be attributed to the defects at the edges of the ribbons, thus not present in the Raman spectra of non-defective silicene and germanene. Particularly the Raman peak corresponding to the D mode is found to be located at around 515 cm-1 for silicene and 270 cm-1 for germanene. The calculated G-like and the D peaks are likely the fingerprints of the Raman spectra of the low-buckled structures of silicene and germanene.[Figure not available: see fulltext.] © 2013 Tsinghua University Press and Springer-Verlag Berlin Heidelberg.

Luttrell L.M.,Medical University of South Carolina | Luttrell L.M.,Ralph hnson Veterans Affairs Medical Center | Maudsley S.,University of Antwerp | Bohn L.M.,Scripps Research Institute
Molecular Pharmacology | Year: 2015

The fact that over 30% of current pharmaceuticals target heptahelical G protein-coupled receptors (GPCRs) attests to their tractability as drug targets. Although GPCR drug development has traditionally focused on conventional agonists and antagonists, the growing appreciation that GPCRs mediate physiologically relevant effects via both G protein and non-G protein effectors has prompted the search for ligands that can "bias" downstream signaling in favor of one or the other process. Biased ligands are novel entities with distinct signaling profiles dictated by ligand structure, and the potential prospect of biased ligands as better drugs has been pleonastically proclaimed. Indeed, preclinical proof-of-concept studies have demonstrated that both G protein and arrestin pathwayselective ligands can promote beneficial effects in vivo while simultaneously antagonizing deleterious ones. But along with opportunity comes added complexity and new challenges for drug discovery. If ligands can be biased, then ligand classification becomes assay dependent, and more nuanced screening approaches are needed to capture ligand efficacy across several dimensions of signaling. Moreover, because the signaling repertoire of biased ligands differs from that of the native agonist, unpredicted responses may arise in vivo as these unbalanced signals propagate. For any given GPCR target, establishing a framework relating in vitro efficacy to in vivo biologic response is crucial to biased drug discovery. This review discusses approaches to describing ligand efficacy in vitro, translating ligand bias into biologic response, and developing a systemslevel understanding of biased agonism in vivo, with the overall goal of overcoming current barriers to developing biased GPCR therapeutics. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

Ansoms A.,University of Antwerp | McKay A.,University of Sussex
Food Policy | Year: 2010

The paper applies a quantitative methodology to study poverty and livelihood profiles on the basis of a large set of variables. It takes the context of post-conflict rural Rwanda for a case study. By means of exploratory tools (i.e. principal component and cluster analysis), it combines variables that capture natural, physical, human, financial and social resources together with environmental factors to identify household groups with varying livelihoods. The paper further explores how these clusters differ with regards the incidence of poverty, livelihood strategies and their respective crop preferences. The paper concludes that Rwandan rural policies should adopt distinct and appropriate interventions for impoverished peasant groups, each having their own particular livelihood profiles. © 2010 Elsevier Ltd.

Ponnet K.,University of Antwerp | Ponnet K.,Higher Institute for Family science
Journal of Youth and Adolescence | Year: 2014

The family stress model proposes that financial stress experienced by parents is associated with problem behavior in adolescents. The present study applied an actor–partner interdependence approach to the family stress model and focused on low-, middle-, and high-income families to broaden our understanding of the pathways by which the financial stress of mothers and fathers are related to adolescent outcomes. The study uses dyadic data (N = 798 heterosexual couples) from the Relationship between Mothers, Fathers and Children study in which two-parent families with an adolescent between 11 and 17 years of age participated. Path-analytic results indicated that in each of the families the association between parents’ financial stress and problem behavior in adolescents is mediated through parents’ depressive symptoms, interparental conflict, and positive parenting. Family stress processes also appear to operate in different ways for low-, middle-, and high-income families. In addition to a higher absolute level of financial stress in low-income families, financial stress experienced by mothers and fathers in these families had significant direct and indirect effects on problem behavior in adolescents, while in middle- and high-income families only significant indirect effects were found. The financial stress of a low-income mother also had a more detrimental impact on her level of depressive feelings than it had on mothers in middle-income families. Furthermore, the study revealed gender differences in the pathways of mothers and fathers. Implications for research, clinical practice, and policy are also discussed. © 2014, Springer Science+Business Media New York.

Guns R.,University of Antwerp
Journal of the American Society for Information Science and Technology | Year: 2013

The Semantic Web has been criticized for not being semantic. This article examines the questions of why and how the Web of Data, expressed in the Resource Description Framework (RDF), has come to be known as the Semantic Web. Contrary to previous papers, we deliberately take a descriptive stance and do not start from preconceived ideas about the nature of semantics. Instead, we mainly base our analysis on early design documents of the (Semantic) Web. The main determining factor is shown to be link typing, coupled with the influence of online metadata. Both factors already were present in early web standards and drafts. Our findings indicate that the Semantic Web is directly linked to older artificial intelligence work, despite occasional claims to the contrary. Because of link typing, the Semantic Web can be considered an example of a semantic network. Originally network representations of the meaning of natural language utterances, semantic networks have eventually come to refer to any networks with typed (usually directed) links. We discuss possible causes for this shift and suggest that it may be due to confounding paradigmatic and syntagmatic semantic relations. © 2013 ASIS&T.

The potential of organic Rankine cycle (ORC) systems is acknowledged by both considerable research and development efforts and an increasing number of applications. Most research aims at improving ORC systems through technical performance optimization of various cycle architectures and working fluids. The assessment and optimization of technical feasibility is at the core of ORC development. Nonetheless, economic feasibility is often decisive when it comes down to considering practical instalments, and therefore an increasing number of publications include an estimate of the costs of the designed ORC system. Various methods are used to estimate ORC costs but the resulting values are rarely discussed with respect to accuracy and validity. The aim of this paper is to provide insight into the methods used to estimate these costs and open the discussion about the interpretation of these results. A review of cost engineering practices shows there has been a long tradition of industrial cost estimation. Several techniques have been developed, but the expected accuracy range of the best techniques used in research varies between 10% and 30%. The quality of the estimates could be improved by establishing up-to-date correlations for the ORC industry in particular. Secondly, the rapidly growing ORC cost literature is briefly reviewed. A graph summarizing the estimated ORC investment costs displays a pattern of decreasing costs for increasing power output. Knowledge on the actual costs of real ORC modules and projects remains scarce. Finally, the investment costs of a known heat recovery ORC system are discussed and the methodologies and accuracies of several approaches are demonstrated using this case as benchmark. The best results are obtained with factorial estimation techniques such as the module costing technique, but the accuracies may diverge by up to +30%. Development of correlations and multiplication factors for ORC technology in particular is likely to improve the quality of the estimates. © 2016 by the author; licensee MDPI.

Dubrovinsky L.,University of Bayreuth | Dubrovinskaia N.,University of Bayreuth | Prakapenka V.B.,University of Chicago | Abakumov A.M.,University of Antwerp
Nature Communications | Year: 2012

Since invention of the diamond anvil cell technique in the late 1950s for studying materials at extreme conditions, the maximum static pressure generated so far at room temperature was reported to be about 400 GPa. Here we show that use of micro-semi-balls made of nanodiamond as second-stage anvils in conventional diamond anvil cells drastically extends the achievable pressure range in static compression experiments to above 600 GPa. Micro-anvils (10-50 μm in diameter) of superhard nanodiamond (with a grain size below ∼50 nm) were synthesized in a large volume press using a newly developed technique. In our pilot experiments on rhenium and gold we have studied the equation of state of rhenium at pressures up to 640 GPa and demonstrated the feasibility and crucial necessity of the in situ ultra high-pressure measurements for accurate determination of material properties at extreme conditions. © 2012 Macmillan Publishers Limited. All rights reserved.

Haughton G.,University of Manchester | Allmendinger P.,University of Cambridge | Oosterlynck S.,University of Antwerp
Environment and Planning A | Year: 2013

This paper examines the proliferation of soft spaces of governance, focusing on planning. We move beyond more functional explanations to explore the politics of soft spaces, more specifically how soft space forms of governance operate as integral to processes of neoliberalisation, highlighting how such state for ms facilitate neoliberalisation through their flexibility and variability. Recent state restructuring of the planning sector and emerging trends for soft spaces in England under the Coalition government proposals are discussed.

De Boeck H.J.,University of Antwerp | Verbeeck H.,Ghent University
Biogeosciences | Year: 2011

Drought periods can have important impacts on plant productivity and ecosystem functioning, but climatic conditions other than the lack of precipitation during droughts have never been quantified and have therefore not been considered explicitly in both experimental and modeling studies. Here, we identify which climatic characteristics deviate from normal during droughts and how these deviations could affect plant responses. Analysis of 609 years of daily data from nine Western European meteorological stations reveals that droughts in the studied region are consistently associated with more sunshine (+45 %), increased mean (+1.6 °C) and maximum (+2.8 °C) air temperatures and vapour pressure deficits that were 51 % higher than under normal conditions. These deviations from normal increase significantly as droughts progress. Using the process-model ORCHIDEE, we simulated droughts consistent with the results of the dataset analysis and compared water and carbon exchange of three different vegetation types during such natural droughts and droughts in which only the precipitation was affected. The comparison revealed contrasting responses: carbon loss was higher under natural drought in grasslands, while increased carbon uptake was found especially in decidious forests. This difference was attributed to better access to water reserves in forest ecosystems which prevented drought stress. This demonstrates that the warmer and sunnier conditions naturally associated with droughts can either improve growth or aggravate drought-related stress, depending on water reserves. As the impacts of including or excluding climatic parameters that correlate with drought are substantial, we propose that both experimental and modeling efforts should take into account other environmental factors than merely precipitation. © 2011 Author(s).

Cotte M.,French National Center for Scientific Research | Cotte M.,European Synchrotron Radiation Facility | Susini J.,European Synchrotron Radiation Facility | Dik J.,Technical University of Delft | Janssens K.,University of Antwerp
Accounts of Chemical Research | Year: 2010

A variety of analytical techniques augmented by the use of synchrotron radiation (SR), such as X-ray fluorescence (SR-XRF) and X-ray diffraction (SR-XRD), are now readily available, and they differ little, conceptually, from their common laboratory counterparts. Because of numerous advantages afforded by SR-based techniques over benchtop versions, however, SR methods have become popular with archaeologists, art historians, curators, and other researchers in the field of cultural heritage (CH). Although the CH community now commonly uses both SR-XRF and SR-XRD, the use of synchrotron-based X-ray absorption spectroscopy (SR-XAS) techniques remains marginal, mostly because CH specialists rarely interact with SR physicists. In this Account, we examine the basic principles and capabilities of XAS techniques in art preservation. XAS techniques offer a combination of features particularly well-suited for the chemical analysis of works of art. The methods are noninvasive, have low detection limits, afford high lateral resolution, and provide exceptional chemical sensitivity. These characteristics are highly desirable for the chemical characterization of precious, heterogeneous, and complex materials. In particular, the chemical mapping capability, with high spatial resolution that provides information about local composition and chemical states, even for trace elements, is a unique asset. The chemistry involved in both the objects history (that is, during fabrication) and future (that is, during preservation and restoration treatments) can be addressed by XAS. On the one hand, many studies seek to explain optical effects occurring in historical glasses or ceramics by probing the molecular environment of relevant chromophores. Hence, XAS can provide insight into craft skills that were mastered years, decades, or centuries ago but were lost over the course of time. On the other hand, XAS can also be used to characterize unwanted reactions, which are then considered alteration phenomena and can dramatically alter the objects original visual properties. In such cases, the bulk elemental composition is usually unchanged. Hence, monitoring oxidation state (or, more generally, other chemical modifications) can be of great importance. Recent applications of XAS in art conservation are reviewed and new trends are discussed, highlighting the value (and future possibilities) of XAS, which remains, given its potential, underutilized in the CH community. © 2010 American Chemical Society.

Janssens K.,University of Antwerp | Dik J.,Technical University of Delft | Cotte M.,European Synchrotron Radiation Facility | Susini J.,European Synchrotron Radiation Facility
Accounts of Chemical Research | Year: 2010

Often, just micrometers below a paintings surface lies a wealth of information, both with Old Masters such as Peter Paul Rubens and Rembrandt van Rijn and with more recent artists of great renown such as Vincent Van Gogh and James Ensor. Subsurface layers may include underdrawing, underpainting, and alterations, and in a growing number of cases conservators have discovered abandoned compositions on paintings, illustrating artists practice of reusing a canvas or panel. The standard methods for studying the inner structure of cultural heritage (CH) artifacts are infrared reflectography and X-ray radiography, techniques that are optionally complemented with the microscopic analysis of cross-sectioned samples. These methods have limitations, but recently, a number of fundamentally new approaches for fully imaging the buildup of hidden paint layers and other complex three-dimensional (3D) substructures have been put into practice. In this Account, we discuss these developments and their recent practical application with CH artifacts. We begin with a tabular summary of 14 IR- and X-ray-based imaging methods and then continue with a discussion of each technique, illustrating CH applications with specific case studies. X-ray-based tomographic and laminographic techniques can be used to generate 3D renditions of artifacts of varying dimensions. These methods are proving invaluable for exploring inner structures, identifying the conservation state, and postulating the original manufacturing technology of metallic and other sculptures. In the analysis of paint layers, terahertz time-domain spectroscopy (THz-TDS) can highlight interfaces between layers in a stratigraphic buildup, whereas macrosopic scanning X-ray fluorescence (MA-XRF) has been employed to measure the distribution of pigments within these layers. This combination of innovative methods provides topographic and color information about the micrometer depth scale, allowing us to look "into" paintings in an entirely new manner. Over the past five years, several new variants of traditional IR- and X-ray-based imaging methods have been implemented by conservators and museums, and the first reports have begun to emerge in the primary research literature. Applying these state-of-the-art techniques in a complementary fashion affords a more comprehensive view of paintings and other artworks. © 2010 American Chemical Society.

Mistiaen W.P.,University of Antwerp
Future Cardiology | Year: 2013

Cardiovascular disease and cancer are leading causes of morbidity and mortality., and can both be present in one patient. In patients with simultaneous disease, the most threatening disease should be treated first. This is usually heart disease, but this can pose specific problems. If percutaneous coronary intervention is preferred, bleeding and thrombotic tendencies have to be taken into account in the subsequent treatment of the malignancy. With coronary artery bypass grafting, the advantages and disadvantages of one- or two-stage procedures, and the use of extracorporeal circulation have to be balanced. Development of heart disease after treatment of malignancy could be due to radiotherapy and chemotherapy. The effects of these cancer treatments have to be taken into account for the treatment options of the heart disease and the postoperative prognosis. © 2013 Future Medicine Ltd.

Bartholomeeusen E.,University of Antwerp
Bulletin de la Société belge d'ophtalmologie | Year: 2012

To evaluate the surgical outcome after intraocular lens exchange in patients implanted with a multifocal intraocular lens (MIOL) who presented impairing visual complaints Department of Ophthalmology, Antwerp University Hospital, Belgium. 25 eyes of 17 consecutive patients underwent IOL exchange. Pre- and postoperative evaluation consisted of: determining patient's complaints, type of IOL before and after IOL exchange, degree of glare and aberrometry (mainly preoperative data), pre and postoperative DCVA and NCVA. Diffractive MIOL were more frequently exchanged than refractive MIOLs and were exchanged when possible by a bag-in-lens IOL. DCVA, NCVA and postoperative subjective complaints improved significantly postoperatively. Eyes with prior Nd:YAG laser capsulotomy needed anterior vitrectomy during MIOL exchange procedure due to the presence of a ruptured anterior vitreous face by the laser treatment. MIOL exchange can be performed safely and with very good visual outcome in patients with severe postoperative visual complaints related to decentered MIOL. Although, patient's postoperative quality of vision remained poor in 7 eyes out of the 25 in this series.

Urban J.,Mendel University in Brno | Bequet R.,University of Antwerp | Mainiero R.,Institute for Applied Plant Biology
Journal of Experimental Botany | Year: 2011

Several electrical methods have been introduced as non-invasive techniques to overcome the limited accessibility to root systems. Among them, the earth impedance method (EIM) represents the most recent development. Applying an electrical field between a cormus and the rooted soil, the EIM measures the absorptive root surface area (ARSA) from grounding resistance patterns. Allometric relationships suggested that this method was a valuable tool. Crucial assumptions for the applicability of the EIM, however, have not been tested experimentally. Focusing on tree root systems, the present study assesses the applicability of the EIM. Six hypotheses, deduced from the EIM approach, were tested in several experiments and the results were compared with conventional methods. None of the hypotheses could be verified and the results allow two major conclusions. First, in terms of an analogue electrical circuit, a tree-root-soil continuum appears as a serial circuit with xylem and soil resistance being the dominant components. Allometric variation in contact resistance, with the latter being the proxy for root surface area, are thus overruled by the spatial and seasonal variation of soil and xylem resistances. Second, in a tree-root-soil continuum, distal roots conduct only a negligible portion of the electric charge. Most of charge carriers leave the root system in the proximal parts of the root-soil interface. © 2010 The Author(s).

Verhaeghe J.,University of Antwerp | Verhaeghe J.,Montreal Neurological Institute | Reader A.J.,Montreal Neurological Institute
Physics in Medicine and Biology | Year: 2013

A novel imaging and signal separation strategy is proposed to be able to separate [18F]FDG and multiple [15O]H2O signals from a simultaneously acquired dynamic PET acquisition of the two tracers. The technique is based on the fact that the dynamics of the two tracers are very distinct. By adopting an appropriate bolus injection strategy and by defining tailored sets of basis functions that model either the FDG or water component, it is possible to separate the FDG and water signal. The basis functions are inspired from the spectral analysis description of dynamic PET studies and are defined as the convolution of estimated generating functions (GFs) with a set of decaying exponential functions. The GFs are estimated from the overall measured head curve, while the decaying exponential functions are pre-determined. In this work, the time activity curves (TACs) are modelled post-reconstruction but the model can be incorporated in a global 4D reconstruction strategy. Extensive PET simulation studies are performed considering single [18F]FDG and 6 [15O]H2O bolus injections for a total acquisition time of 75 min. The proposed method is evaluated at multiple noise levels and different parameters were estimated such as [18F]FDG uptake and blood flow estimated from the [15O]H2O component, requiring a full dynamic analysis of the two components, static images of [ 18F]FDG and the water components as well as [15O]H 2O activation. It is shown that the resulting images and parametric values in ROIs are comparable to images obtained from separate imaging, illustrating the feasibility of simultaneous imaging of [18F]FDG and [15O]H2O components. © 2013 Institute of Physics and Engineering in Medicine.

Egghe L.,Hasselt University | Egghe L.,University of Antwerp
Journal of Informetrics | Year: 2012

The recently awakened discussion on the usability of averages of ratios (AoR) compared to ratios of averages (RoA) has led to the mathematical results in this paper. Based on the empirical results in Larivière and Gingras (2011) we prove, under reasonable conditions, the following relations between AoR and RoA for a set of points:. (i)The regression line of RoA in function of AoR is the first bisectrix.(ii)(AoR-RoA)/AoR in function of the number N of papers is a cloud of points comprised between a multiple of 1/N and -1/N.(iii)(AoR-RoA)/AoR versus RoA has a decreasing regression line. © 2012 Elsevier Ltd.

Pyeritz R.E.,University of Pennsylvania | Loeys B.,University of Antwerp
American Journal of Medical Genetics, Part A | Year: 2012

In the nearly quarter-century since the first international symposium on Marfan syndrome, enormous progress has been achieved in clinical, translational, and basic research. The 8th symposium, at the end of 2010, provides a useful summary of the current status of investigations, reveals why life-expectancy has improved so markedly during the past 30 years, and lays out a clear path for future endeavors, not only in Marfan syndrome, but in the expanding array of conditions related either through phenotype or pathogenesis. © 2011 Wiley Periodicals, Inc.

De Backer W.,University of Antwerp
Panminerva Medica | Year: 2013

Obstructive sleep apnea/hypopnea syndrome (OSAHS) is characterized by recurrent episodes of partial or complete upper airway collapse during sleep that is highlighted by a reduction in, or complete cessation of, airflow despite documented on going inspiratory efforts. Due to the lack of adequate alveolar ventilation that results from the upper airway narrowing, oxygen saturation may drop and partial pressure of COs may occasionally increase. The events are mostly terminated by arousals. Clinical consequences are excessive daytime sleepiness related to the sleep disruption. Minimal diagnostic criteria have been defined for OSAHS. Patients should have excessive daytime sleepiness that can not be better explained by other factors, or experience two or more of the following symptoms, again that are not better explained by other factors: choking or gasping during sleep; recurrent awakenings from sleep; un-refreshing sleep; daytime fatigue; and impaired concentration. All patients should have more than five obstructed breathing events per hour during sleep. An obstructive apnea or hypopnoea can be defined as an event that lasts for 510 s and is characterized by an absence or a decrease from baseline in the amplitude of a valid measure of breathing during sleep that either reaches >50% with an oxygen desaturation of 3% or an arousal (alternatively a 30% reduction with 4% desaturation). The American Academy of Sleep Medicine (AASM) recommends these definitions. The Task Force of the AASM also states that there are common pathogenic mechanisms for obstructive apnea syndrome, central apnea syndrome, sleep hypoventilation syndrome and Cheyne-Stokes breathing. It was more preferable to discuss each of these separately; although, they could be placed under the common denominator of "sleep-disordered breathing syndrome". The definition of OSAHS using two components, daytime symptoms and breathing pattern disturbances during sleep, may suggest that there is a tight correlation between the two. However, unfortunately this is not the case. The breathing pattern abnormalities, mostly described by an Apnea/Hj popnoea Index (AHI), only weakly correlate with quantified measures of sleepiness, such as the Epworth Sleepiness Scale (ESS). This probably means that interindividual sensitivity, with some individuals coping better with sleep fragmentation than others, does compromise the relationship between the AHI and daytime sleepiness scores. In addition, epidemiological studies show a broad range of sleepiness in the general population. Obviously, epidemiological studies investigating the prevalence of OSAHS are all biased by the lack of a uniform definition. The prevalence of an AHI of >5 events'h-1 in a general population (without taking into account symptoms of sleepiness) has previously been estimated to be 24% in a male population. When symptoms of sleepiness were also taken into account, the prevalence decreased to 4% in males and 2% in females.

Dooling S.,German Electron Synchrotron | Hautmann F.,University of Sussex | Hautmann F.,Rutherford Appleton Laboratory | Hautmann F.,University of Oxford | And 2 more authors.
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

If studies of electroweak gauge boson final states at the Large Hadron Collider, for Standard Model physics and beyond, are sensitive to effects of the initial state's transverse momentum distribution, appropriate generalizations of QCD shower evolution are required. We propose a method to do this based on QCD transverse momentum dependent (TMD) factorization at high energy. The method incorporates experimental information from the high-precision deep inelastic scattering (DIS) measurements, and includes experimental and theoretical uncertainties on TMD parton density functions. We illustrate the approach presenting results for production of W-boson + n jets at the LHC, including azimuthal correlations and subleading jet distributions. © 2014 The Authors. Published by Elsevier B.V.

Geerts F.,University of Antwerp | Mecca G.,University of Basilicata | Papotti P.,Qatar Computing Research Institute QCRI | Santoro D.,University of Basilicata | Santoro D.,Third University of Rome
Proceedings of the VLDB Endowment | Year: 2013

Data-cleaning (or data-repairing) is considered a crucial problem in many database-related tasks. It consists in making a database consistent with respect to a set of given constraints. In recent years, repairing methods have been proposed for several classes of constraints. However, these methods rely on ad hoc decisions and tend to hard-code the strategy to repair conflicting values. As a consequence, there is currently no general algorithm to solve database repairing problems that involve different kinds of constraints and different strategies to select preferred values. In this paper we develop a uniform framework to solve this problem. We propose a new semantics for repairs, and a chase-based algorithm to compute minimal solutions. We implemented the framework in a DBMSbased prototype, and we report experimental results that confirm its good scalability and superior quality in computing repairs.

Segers V.F.M.,University of Antwerp | Lee R.T.,Harvard University
Circulation Research | Year: 2011

Transplantation of stem cells into the heart can improve cardiac function after myocardial infarction and in chronic heart failure, but the extent of benefit and of reproducibility of this approach are insufficient. Survival of transplanted cells into myocardium is poor, and new strategies are needed to enhance stem cell differentiation and survival in vivo. In this review, we describe how biomaterials can enhance stem cell function in the heart. Biomaterials can mimic or include naturally occurring extracellular matrix and also instruct stem cell function in different ways. Biomaterials can promote angiogenesis, enhance engraftment and differentiation of stem cells, and accelerate electromechanical integration of transplanted stem cells. Biomaterials can also be used to deliver proteins, genes, or small RNAs together with stem cells. Furthermore, recent evidence indicates that the biophysical environment of stem cells is crucial for their proliferation and differentiation, as well as their electromechanical integration. Many approaches in regenerative medicine will likely ultimately require integration of molecularly designed biomaterials and stem cell biology to develop stable tissue regeneration. © 2011 American Heart Association, Inc.

Brauers W.K.M.,University of Antwerp | Zavadskas E.K.,Vilnius Gediminas Technical University
Informatica | Year: 2012

Multi-Objective Optimization takes care of different objectives with the objectives keeping their own units. The internal mechanical solution of a Ratio System, producing dimensionless numbers, is preferred. The ratio system creates the opportunity to use a second approach: a Reference Point Theory, which uses the ratios of the ratio system. This overall theory is called MOORA (Multi-Objective Optimization by Ratio Analysis). The results are still more convincing if a Full Multiplicative Form is added forming MULTIMOORA. The control by three different approaches forms a guaranty for a solution being as non-subjective as possible. MULTIMOORA, tested after robustness, showed positive results. © 2012 Vilnius University.

Sihoe A.D.L.,University of Hong Kong | Van Schil P.,University of Antwerp
Lung Cancer | Year: 2014

Sublobar resection for lung cancer - whether non-anatomic wedge resection or anatomic segmentectomy - has emerged as a credible alternative to lobectomy for the surgical treatment of selected patients with lung cancer. Sublobar resection promises to cause less pulmonary compromise in such patients. Emerging evidence suggests that sublobar resection may offer survival outcomes approaching that of lobectomy for lung cancer patients whose disease meets the following criteria: stage IA disease only; tumor up to 2-3. cm diameter; peripheral location of tumor in the lung; and predominantly ground-glass (non-solid) appearance on CT imaging. The best results are obtained with segmentectomy (as opposed to wedge resection) and complete lymph node dissection.Nevertheless, the evidence is currently still limited, and the above criteria are met only in a minority of patients. Large randomized trials are underway to define the clinical role of sublobar resections, and results are eagerly anticipated. Until that time, lobectomy should still be regarded as the mainstay of surgical therapy for patients with early stage lung cancer at present. © 2014 Elsevier Ireland Ltd.

Adams F.,University of Antwerp
Journal of Analytical Atomic Spectrometry | Year: 2014

Analytical methods were developed or refined to link the composition and structure of man-made and natural materials down to the nanoscale dimensions to their functional behaviour at the macroscopic scale. Most of the techniques now available are based the interaction of the sample with electromagnetic radiation or particles. In these techniques, the ability for observation and analysis expanded over the last 50 years from rather straightforward measurements in the narrow wavelength range in, or near to, the visible region, to large portions of the electromagnetic spectrum and complex higher-order interactions in multi-spectral and hyper-spectral imaging methods. With imaging analysis and other analytical methodologies that produce massive amounts of data, analytical chemistry is increasingly transformed into a discovery-driven, shotgun methodology, instead of a hypothesis-driven, targeted methodology. In such conditions, standard metrological concepts (uncertainty, validation, and/or traceability to fundamental standards⋯) lose their central guiding role. This journal is © 2014 the Partner Organisations.

Van Schil P.E.,University of Antwerp
European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery | Year: 2013

On 10 February 2012, a Strategic Conference was organized by the European Association for Cardio-Thoracic Surgery (EACTS) in Windsor during the inauguration of the newly acquired EACTS house. In this review, the present and future of thoracic surgery are discussed. With the creation of the Thoracic Domain, thoracic surgery has been strengthened and made clearly visible within the general EACTS structure. A clearly identified thoracic track is provided during the Annual Congress. Specific working groups have been created that deal with varying topics of thoracic surgery and diseases of the chest. The European School of Cardiothoracic Surgery has been restructured, providing not only theoretical but also practical education in thoracic surgery. At national and international levels, interdisciplinary cooperation is encouraged. Harmonization of thoracic training within Europe is necessary to allow better exchange between different countries. Guidelines dealing with specific thoracic procedures should be further developed. The Thoracic Domain of EACTS will remain a key player in promoting thoracic surgery in Europe and internationally, and in providing high-level scientific output, education and training in thoracic surgery and diseases of the chest, which requires continuous, close cooperation between thoracic and cardiothoracic surgeons.

Zimek A.,University of Alberta | Vreeken J.,University of Antwerp
Machine Learning | Year: 2013

In this position paper, we discuss how different branches of research on clustering and pattern mining, while rather different at first glance, in fact have a lot in common and can learn a lot from each other’s solutions and approaches. We give brief introductions to the fundamental problems of different sub-fields of clustering, especially focusing on subspace clustering, ensemble clustering, alternative (as a variant of constraint) clustering, and multiview clustering (as a variant of alternative clustering). Second, we relate a representative of these areas, subspace clustering, to pattern mining. We show that, while these areas use different vocabularies and intuitions, they share common roots and they are exposed to essentially the same fundamental problems; in particular, we detail how certain problems currently faced by the one field, have been solved by the other field, and vice versa.The purpose of our survey is to take first steps towards bridging the linguistic gap between different (sub-) communities and to make researchers from different fields aware of the existence of similar problems (and, partly, of similar solutions or of solutions that could be transferred) in the literature on the other research topic. © 2013, The Author(s).

Asard H.,University of Antwerp | Barbaro R.,University of Bologna | Trost P.,University of Bologna | Berczi A.,Institute of Biophysics
Antioxidants and Redox Signaling | Year: 2013

Significance: Cytochromes b561 (CYB561s) constitute a family of trans-membrane (TM), di-heme proteins, occurring in a variety of organs and cell types, in plants and animals, and using ascorbate (ASC) as an electron donor. CYB561s function as monodehydroascorbate reductase, regenerating ASC, and as Fe3+-reductases, providing reduced iron for TM transport. A CYB561-core domain is also associated with dopamine β-monooxygenase redox domains (DOMON) in ubiquitous CYBDOM proteins. In plants, CYBDOMs form large protein families. Physiological functions supported by CYB561s and CYBDOMs include stress defense, cell wall modifications, iron metabolism, tumor suppression, and various neurological processes, including memory retention. CYB561s, therefore, significantly broaden our view on the physiological roles of ASC. Recent Advances: The ubiquitous nature of CYB561s is only recently being recognized. Significant advances have been made through the study of recombinant CYB561s, revealing structural and functional properties of a unique "two-heme four-helix" protein configuration. In addition, the DOMON domains of CYBDOMs are suggested to contain another heme b. Critical Issues: New CYB561 proteins are still being identified, and there is a need to provide an insight and overview on the various roles of these proteins and their structural properties. Future Directions: Mutant studies will reveal in greater detail the mechanisms by which CYB561s and CYBDOMs participate in cell metabolism in plants and animals. Moreover, the availability of efficient heterologous expression systems should allow protein crystallization, more detailed (atomic-level) structural information, and insights into the intra-molecular mechanism of electron transport. © 2013, Mary Ann Liebert, Inc.

Eelbode D.,University of Antwerp | Smid D.,Charles University
Complex Analysis and Operator Theory | Year: 2012

This paper deals with the problem of factorizing integer powers of the Laplace operator acting on functions taking values in higher spin representations. This is a far-reaching generalization of the well-known fact that the square of the Dirac operator is equal to the Laplace operator. Using algebraic properties of projections of Stein-Weiss gradients, i. e. generalized Rarita-Schwinger and twistor operators, we give a sharp upper bound on the order of polyharmonicity for functions with values in a given representation with half-integral highest weight. © 2011 Springer Basel AG.

Goebel M.-O.,Leibniz University of Hanover | Bachmann J.,Leibniz University of Hanover | Reichstein M.,Max Planck Institute for Biogeochemistry | Janssens I.A.,University of Antwerp | Guggenberger G.,Leibniz University of Hanover
Global Change Biology | Year: 2011

Earth system models associate the ongoing global warming with increasing frequency and intensity of extreme events such as droughts and heat waves. The carbon balance of soils may be more sensitive to the impact of such extremes than to homogeneously distributed changes in soil temperature (Ts) or soil water content (θs). One parameter influenced by more pronounced drying/rewetting cycles or increases in Ts is the wettability of soils. Results from laboratory and field studies showed that low θs, particularly in combination with high Ts can increase soil water repellency (SWR). Recent studies have provided evidence that the stability of soil organic matter (SOM) against microbial decomposition is substantially enhanced in water repellent soils. This review hypothesizes that SWR is an important SOM stabilization mechanism that could become more important because of the increase in extreme events. We discuss wettability-induced changes in soil moisture distribution and in soil aggregate turnover as the main mechanisms explaining the reduced mineralization of SOM with increasing SWR. The creation of preferential flow paths and subsequent uneven penetration of rainwater may cause a long-term reduction of soil water availability, affecting both microorganisms and plants. We conclude that climate change-induced SWR may intensify the effects of climatic drought and thus affects ecosystem processes such as SOM decomposition and plant productivity, as well as changes in vegetation and microbial community structure. Future research on biosphere-climate interactions should consider the effects of increasing SWR on soil moisture and subsequently on both microbial activity and plant productivity, which ultimately determine the overall carbon balance. © 2011 Blackwell Publishing Ltd.

Daelemans W.,University of Antwerp
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2013

Computational stylometry, as in authorship attribution or profiling, has a large potential for applications in diverse areas: literary science, forensics, language psychology, sociolinguistics, even medical diagnosis. Yet, many of the basic research questions of this field are not studied systematically or even at all. In this paper we will go into these problems, and suggest that a reinterpretation of current and historical methods in the framework and methodology of machine learning of natural language processing would be helpful. We also argue for more attention in research for explanation in computational stylometry as opposed to purely quantitative evaluation measures and propose a strategy for data collection and analysis for achieving progress in computational stylometry. We also introduce a fairly new application of computational stylometry in internet security. © 2013 Springer-Verlag.

The aim of this study is to investigate if reported childhood food habits predict the food habits of students at present. Questions addressed are: does the memory of childhood family meals promote commensality among students? Does the memory of (grand)parents' cooking influence students' cooking? And, is there still a gender difference in passing on everyday cooking skills? Using a cross-sectional survey, 104 students were asked about their current eating and cooking habits, and their eating habits and the cooking behavior of their (grand)parents during their childhood. Results show that frequencies in reported childhood family meals predict frequencies of students' commensality at present. The effects appear for breakfast and dinner, and stay within the same meal: recalled childhood family breakfasts predict current breakfast commensality, recalled childhood family dinners predict current dinner commensality. In terms of recalled cookery of (grand)parents and the use of family recipes a matrilineal dominance can be observed. Mothers are most influential, and maternal grandmothers outscore paternal grandmothers. Yet, fathers' childhood cooking did not pass unnoticed either. They seem to influence male students' cookery. Overall, in a life-stage of transgression students appear to maintain recalled childhood food rituals. Suggestions are discussed to further validate these results. © 2013 Elsevier Ltd.

Hautmann F.,University of Sussex | Hautmann F.,Rutherford Appleton Laboratory | Hautmann F.,University of Oxford | Jung H.,German Electron Synchrotron | Jung H.,University of Antwerp
Nuclear Physics B | Year: 2014

The combined measurements of proton's structure functions in deeply inelastic scattering at the HERA collider provide high-precision data capable of constraining parton density functions over a wide range of the kinematic variables. We perform fits to these data using transverse momentum dependent QCD factorization and CCFM evolution. The results of the fits to precision measurements are used to make a determination of the nonperturbative transverse momentum dependent gluon density function, including experimental and theoretical uncertainties. We present an application of this density function to vector boson + jet production processes at the LHC. © 2014 The Authors.

Pena-Abaurrea M.,IQOG CSIC | Covaci A.,University of Antwerp | Ramos L.,IQOG CSIC
Journal of Chromatography A | Year: 2011

This study evaluates comprehensive two-dimensional gas chromatography (GC × GC) coupled to time-of-flight mass spectrometry (GC × GC-ToF MS) for the simultaneous analysis of several classes of organobromines (OBs), including polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs), methoxylated PBDEs (MeO-PBDEs), several halogenated naturally produced compounds (HNPs) and eight novel brominated flame retardants (NBFRs), polybrominated hexahydroxanthene derivates (PBHDs), 2,4,6-tribromoanisole and a mixed halogenated compound (MHC-1), in bluefin tuna muscles. The proposed methodology maximised separation of both within and among OB families, and among these and other halogenated micropollutants detected in these samples and co-extracted matrix components. Special attention has been paid to solve co-elution problems observed during the analysis of OBs with one-dimensional GC-based techniques. Satisfactory separation among several relevant PBDEs and MeO-PBDEs has been obtained allowing their unambiguous determination in a single run. Additional studies were conducted to identify selected NBFRs and HNPs. 2,4-Dibromoanisole, a dibromophenol isomer and hexabromobenzene were identified in the investigated samples. Several new tri- and tetra-BHD derivates were also identified, indicating that these compounds could apparently exist as structured families in nature. In addition, a tetrabrominated diMeO-biphenyl and two tetrabrominated diMeO-BDEs were also tentatively identified. © 2011 Elsevier B.V.

Nuyts J.,University of Antwerp
Journal of Pragmatics | Year: 2015

This brief 'conceptual' paper offers some reflections on the status of 'subjectivity' in language. Section 1 highlights the differences and correlations between a few of the major current concepts of subjectivity, notably the 'general' ones by Traugott (1989), Traugott and Dasher, 2002) and Langacker (1990, 1999, 2008), and the specific one(s) as postulated in the context of the analysis of modal expressions (Nuyts, 2001, 2012). Section 2 then zooms in on the 'functional' role in language use of the modality-related - or probably more accurately, attitude-related - dimension, focusing on its discursive status. Section 3, finally, returns to the issue of how the major notions of subjectivity discussed in Section 1 relate, and how this can only be understood with reference to both the conceptual and the discursive status of the phenomena at stake. © 2015 Elsevier B.V.

Vanderelst D.,University of Antwerp | Speybroeck N.,Catholic University of Louvain
Malaria Journal | Year: 2013

Background: Many studies have assessed the level of bed net coverage in populations at risk of malaria infection. These revealed large variations in bed net use across countries, regions and social strata. Such studies are often aimed at identifying populations with low access to bed nets that should be prioritized in future interventions. However, often spatial differences in malaria endemicity are not taken into account. By ignoring variability in malaria endemicity, these studies prioritize populations with little access to bed nets, even if these happen to live in low endemicity areas. Conversely, populations living in regions with high malaria endemicity will receive a lower priority once a seizable proportion is protected by bed nets. Adequately assigning priorities requires accounting for both the current level of bed net coverage and the local malaria endemicity. Indeed, as shown here for 23 African countries, there is no correlation between the level of bed net coverage and the level of malaria endemicity in a region. Therefore, the need for future interventions can not be assessed based on current bed net coverage alone. This paper proposes the Adjusted Bed net Coverage (ABC) statistic as a measure taking into account both local malaria endemicity and the level of bed net coverage. The measure allows setting priorities for future interventions taking into account both local malaria endemicity and bed net coverage. Methods. A mathematical formulation of the ABC as a weighted difference of bed net coverage and malaria endemicity is presented. The formulation is parameterized based on a model of malaria epidemiology (Smith et al. Trends Parasitol 25:511-516, 2009). By parameterizing the ABC based on this model, the ABC as used in this paper is proxy for the steady-state malaria burden given the current level of bed net coverage. Data on the bed net coverage in under five year olds and malaria endemicity in 23 Sub-Saharan countries is used to show that the ABC prioritizes different populations than the level of bed net coverage by itself. Data from the following countries was used: Angola, Burkina Faso, Burundi, Cameroon, Congo Democratic Republic, Ethiopia, Ghana, Guinea, Kenya, Liberia, Madagascar, Malawi, Mali, Mozambique, Namibia, Nigeria, Rwanda, Senegal, Sierra Leone, Tanzania, Uganda, Zambia and Zimbabwe. The priority order given by the ABC and the bed net coverage are compared at the countries' level, the first level administrative divisions and for five different wealth quintiles. Results: Both at national level and at the level of the administrative divisions the ABC suggests a different priority order for selecting countries and divisions for future interventions. When taking into account malaria endemicity, measures assessing equality in access to bed nets across wealth quintiles, such as slopes of inequality, are prone to change. This suggests that when assessing inequality in access to bed nets one should take into account the local malaria endemicity for populations from different wealth quintiles. Conclusion: Accounting for malaria endemicity highlights different countries, regions and socio-economic strata for future intervention than the bed net coverage by itself. Therefore, care should be taken to factor out any effects of local malaria endemicity in assessing bed net coverage and in prioritizing populations for further scale-up of bed net coverage. The ABC is proposed as a simple means to do this that is derived from an existing model of malaria epidemiology. © 2013 Vanderelst and Speybroeck; licensee BioMed Central Ltd.

Dylla M.,Max Planck Institute for Informatics | Miliaraki I.,Max Planck Institute for Informatics | Theobald M.,University of Antwerp
Proceedings - International Conference on Data Engineering | Year: 2013

We investigate a novel approach of computing confidence bounds for top-k ranking queries in probabilistic databases with non-materialized views. Unlike related approaches, we present an exact pruning algorithm for finding the top-ranked query answers according to their marginal probabilities without the need to first materialize all answer candidates via the views. Specifically, we consider conjunctive queries over multiple levels of select-project-join views, the latter of which are cast into Datalog rules which we ground in a top-down fashion directly at query processing time. To our knowledge, this work is the first to address integrated data and confidence computations for intensional query evaluations in the context of probabilistic databases by considering confidence bounds over first-order lineage formulas. We extend our query processing techniques by a tool-suite of scheduling strategies based on selectivity estimation and the expected impact on confidence bounds. Further extensions to our query processing strategies include improved top-k bounds in the case when sorted relations are available as input, as well as the consideration of recursive rules. Experiments with large datasets demonstrate significant runtime improvements of our approach compared to both exact and sampling-based top-k methods over probabilistic data. © 2013 IEEE.

Kuppens A.H.,University of Antwerp
Learning, Media and Technology | Year: 2010

A number of experimental studies have demonstrated the incidental acquisition of a foreign language by children and adolescents when watching foreign language television. While such experiments can only establish short-term effects, this article investigates the extent to which children's foreign language skills benefit from their long-term consumption of media. An empirical study conducted in the Flemish (Dutch-speaking) area of Belgium compared the self-reported use of three English language media by 374 pupils in the last year of primary education with their scores on two oral translation tests: one from Dutch to English and one vice versa. Two general linear model analyses of variance reveal that pupils who frequently watch subtitled English television programs and movies perform significantly better on both tests. Interestingly, the effect of watching subtitled television and movies is stronger with girls than with boys. Furthermore, playing English computer games positively influences the scores on the English-Dutch test. © 2010 Taylor & Francis.

Egghe L.,Hasselt University | Egghe L.,University of Antwerp
Journal of Informetrics | Year: 2011

We define the generalized Wu- and Kosmulski-indices, allowing for general parameters of multiplication or exponentiation. We then present formulae for these generalized indices in a Lotkaian framework.Next we characterise these indices in terms of their dependence on the quotient of the average number of items per source in the m-core divided by the overall average (m is any generalized Wu- or Kosmulski-index).As a consequence of these results we show that the fraction of used items (used in the definition of m) in the m-core is independent of the parameter and equals one divided by the overall average. © 2011 Elsevier Ltd.

Mathauer I.,World Health Organization | Carrin G.,University of Antwerp
Health Policy | Year: 2011

Many low- and middle income countries heavily rely on out-of-pocket health care expenditure. The challenge for these countries is how to modify their health financing system in order to achieve universal coverage. This paper proposes an analytical framework for undertaking a systematic review of a health financing system and its performance on the basis of which to identify adequate changes to enhance the move towards universal coverage.The distinctive characteristic of this framework is the focus on institutional design and organizational practice of health financing, on which health financing performance is contingent. Institutional design is understood as formal rules, namely legal and regulatory provisions relating to health financing; organizational practice refers to the way organizational actors implement and comply with these rules. Health financing performance is operationalized into nine generic health financing performance indicators.Inadequate performance can be caused by six types of bottlenecks in institutional design and organizational practice. Accordingly, six types of improvement measures are proposed to address these bottlenecks.The institutional design and organizational practice of a health financing system can be actively developed, modified or strengthened. By understanding the incentive environment within a health financing system, the potential impacts of the proposed changes can be anticipated. © 2010 Elsevier Ireland Ltd.

Van Gaal L.,University of Antwerp | Scheen A.,University of Liege
Diabetes Care | Year: 2015

Diabetes is a growing global health concern, as is obesity. Diabetes and obesity are intrinsically linked: obesity increases the risk of diabetes and also contributes to disease progression and cardiovascular disease. Although the benefits of weight loss in the prevention of diabetes and as a critical component of managing the condition are well established, weight reduction remains challenging for individuals with type 2 diabetes due to a host of metabolic and psychological factors. For many patients, lifestyle intervention is not enough to achieve weight loss, and alternative options, such as pharmacotherapy, need to be considered. However, many traditional glucose-loweringmedications may lead to weight gain. This article focuses on the potential of currently available pharmacological strategies and on emerging approaches in development to support the glycemic and weight-loss goals of individuals with type 2 diabetes. Two pharmacotherapy types are considered: Those developed primarily for blood glucose control that have a favorable effect on body weight and those developed primarily to induce weight loss that have a favorable effect on blood glucose control. Finally, the potential of combination therapies for the management of obese patients with type 2 diabetes is discussed. ©2015 by the American Diabetes Association.

De Florio V.,University of Antwerp
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2013

The variability in the conditions of deployment environments introduces new challenges for the resilience of our computer systems. As a response to said challenges, novel approaches must be devised so that identity robustness be guaranteed autonomously and with minimal overhead. This paper provides the elements of one such approach. First, building on top of previous results, we formulate a metric framework to compare specific aspects of the resilience of systems and environments. Such framework is then put to use by sketching the elements of a handshake mechanism between systems declaring their resilience figures and environments stating their minimal resilience requirements. Despite its simple formulation it is shown how said mechanism enables scenarios in which resilience can be autonomously enhanced, e.g., through forms of social collaboration. This paves the way to future "auto-resilient" systems, namely systems able to reason and revise their own architectures and organisations so as to optimally guarantee identity persistence. © 2013 Springer-Verlag.

van Hal G.,University of Antwerp
Psychology Research and Behavior Management | Year: 2015

The recent economic crisis has led to many negative consequences, not the least having to do with the mental health and well-being of the populations involved. Although some researchers say it is still too early to speak about a relationship between the economic crisis and a rise in mental health problems resulting in suicides, there is solid evidence for the existence of such a relationship. However, several moderating or mediating mechanisms can also play a role. The main reactions of most policy makers to the economic crisis are (severe) austerity measures. These measures seem to have, however, a detrimental effect on the mental health of the population: Just when people have the highest need for mental help, cost-cutting measures in the health care sector lead to a (substantial) drop in the supply of services for the prevention, early detection, and cure of mental health problems. Policy makers should support moderating mechanisms such as financial and psychological coping and acculturation and the role of primary health care workers in the early detection of suicidal thoughts, suicide attempts, and suicide in times of economic recession. Several examples show that the countries best off regarding the mental health of their populations during the economic crisis are those countries with the strongest social safety net. Therefore, instead of cutting back on health care and social welfare measures, policy makers should in the future invest even more in social protection measures during economic crises. © 2015 Van Hal.

Van Houdt B.,University of Antwerp
Performance Evaluation | Year: 2012

In this paper we study a broad class of semi-Markovian queues introduced by Sengupta. This class contains many classical queues such as the GI/M/1 queue, SM/MAP/1 queue and others, as well as queues with correlated inter-arrival and service times. Queues belonging to this class are characterized by a set of matrices of size m and Sengupta showed that its waiting time distribution can be represented as a phase-type distribution of order m. For the special case of the SM/MAP/1 queue without correlated service and inter-arrival times the queue length distribution was also shown to be phase-type of order m, but no derivation for the queue length was provided in the general case. This paper introduces an order m 2 phase-type representation (κ,K) for the queue length distribution in the general case and proves that the order m 2 of the distribution cannot be further reduced in general. A matrix geometric representation (κ,K,ν) is also established for the number of type τ⊆{1,⋯,m} customers in the system, where a customer is of type τ if the phase in which it completes service belongs to τ. We derive these results in both discrete and continuous time and also discuss the numerical procedure to compute (κ,K,ν). When the arrivals have a Markovian structure, the numerical procedure is reduced to solving a Quasi-Birth-Death (for the discrete time case) or fluid queue (for the continuous time case). Finally, by combining a result of Sengupta and Ozawa, we provide a simple formula to compute the order m phase-type representation of the waiting time in a MAP/MAP/1 queue without correlated service and inter-arrival times, using the R matrix of a Quasi-Birth-Death Markov chain. © 2012 Elsevier B.V. All rights reserved.

Novais S.C.,University of Aveiro | De Coen W.,University of Antwerp | Amorim M.J.,University of Aveiro
Environmental Toxicology and Chemistry | Year: 2012

Metal ecotoxicity to soil organisms (for example, in enchytraeids) has been addressed mainly by assessing effects on survival and reproduction, but very little is known about the underlying molecular mechanisms of responses. The main purpose of the present study was to assess and compare the transcriptional responses of Enchytraeus albidus to an essential (Zn) and a nonessential (Cd) metal. Exposure was performed with two concentrations with a known effect on reproduction (effective concentration for 50% [EC50] and 90% [EC90]) at three time points (2, 4, and 8 d). Results showed that transcriptional responses were influenced by exposure duration but, independently of that, the mechanisms of response to Cd and Zn were consistently different. Both metals affected pathways related to the regulation of gene expression, calcium homeostasis, and cellular respiration. Mechanisms of toxicity that were exclusively associated with Cd exposures were the inhibition of DNA repair and the impairment of ubiquitin-mediated proteolysis. The microarray for E. albidus was a useful tool for detecting molecular pathways affected by metal exposures. Transcriptional responses strongly correlated with known mechanisms of Cd and Zn responses in other organisms, suggesting cross-species conserved mechanisms of action. It should be highlighted not only that the authors could retrieve mechanistic information but also that genes responded within 2 to 8 d of exposure. This represents an additional advantage of using such molecular endpoints as a complement to the traditional, more time-consuming endpoints. © 2012 SETAC.

Miettinen P.,Max Planck Institute for Informatics | Vreeken J.,University of Antwerp
Proceedings of the ACM SIGKDD International Conference on Knowledge Discovery and Data Mining | Year: 2011

Matrix factorizations-where a given data matrix is approximated by a product of two or more factor matrices-are powerful data mining tools. Among other tasks, matrix factorizations are often used to separate global structure from noise. This, however, requires solving the'model order selection problem'of determining where fine-grained structure stops, and noise starts, i.e., what is the proper size of the factor matrices. Boolean matrix factorization (BMF)-where data, factors, and matrix product are Boolean-has received increased attention from the data mining community in recent years. The technique has desirable properties, such as high interpretability and natural sparsity. But so far no method for selecting the correct model order for BMF has been available. In this paper we propose to use the Minimum Description Length (MDL) principle for this task. Besides solving the problem, this well-founded approach has numerous benefits, e.g., it is automatic, does not require a likelihood function, is fast, and, as experiments show, is highly accurate. We formulate the description length function for BMF in general- making it applicable for any BMF algorithm. We extend an existing algorithm for BMF to use MDL to identify the best Boolean matrix factorization, analyze the complexity of the problem, and perform an extensive experimental evaluation to study its behavior. Copyright 2011 ACM.

Subbaiyan N.K.,Los Alamos National Laboratory | Cambre S.,Los Alamos National Laboratory | Cambre S.,University of Antwerp | Parra-Vasquez A.N.G.,Los Alamos National Laboratory | And 3 more authors.
ACS Nano | Year: 2014

Aqueous two-phase extraction has recently been demonstrated as a new method to separate single-wall carbon nanotubes (SWCNTs). In this work, we determined that the mechanism of separation is driven by the hydrophobicity of the surfactant, or combination of surfactants, at the SWCNT surface. This knowledge allowed us to develop a simple approach for obtaining highly enriched single-chirality suspensions in only 1 or 2 steps. These results were obtained by strategically combining multiple surfactants with different diameter-dependent binding affinities for SWCNTs and salts that readjust the surfactant structure within the mixed micelle surrounding the SWCNTs. The procedure is successfully applied to SWCNTs from different sources (CoMoCAT and HiPco) with various diameter distributions (from 0.53 to 1.2 nm). Each separation step is characterized by optical absorption, resonant Raman, and photoluminescence excitation spectroscopies. By determining the SWCNT sorting mechanism, we were able to develop a new set of parameters that separated another chirality. © 2014 American Chemical Society.

Verbruggen A.,University of Antwerp
Energy Efficiency | Year: 2012

This methodological paper has a didactic goal: improving our understanding of what "cost optimal energy performance of buildings" means and how financial appraisal of efficiency investments must be set up. Three items merit improvement. First, focus on the endowment character of energy performance of long-living assets like buildings. Second, defining cost optimal requires more than a comparative static trade-off scheme; cost optimal refers to dynamic efficiency, which results from technology dynamics induced by changes in society and policy. Third, financial appraisal is a more complex issue than simple net present value and life cycle cost calculations. It must reflect the time sequential dynamics of real-life processes including real-life decision making. Financial appraisal is embedded in a complex framework made up by three dimensions: future time, doubt and irrevocability. The latter dimension connects with issues like lock-in and path dependency that are generally overlooked in net present value calculations. This may lead to very erroneous recommendations regarding efficiency investments, in particular regarding the energy performance endowment of buildings. Mostly irrevocability is used as an argument to "wait and learn" what has, for example, blocked the pace of climate policy. But the opposite "choose or lose" is the logical outcome when the methodology is fed with evidenced expectations. The latter boosts energy efficiency to its boundaries, saving it from the middle-of-the-river quagmire where incomplete appraisals are dropping it too often (making the good the worst enemy of the best). © 2012 Springer Science+Business Media B.V.

Kooy R.F.,University of Antwerp
F1000 Biology Reports | Year: 2010

Over the last few years, large cohorts of patients with distinct brain disorders of neuropsychiatric and neurological origin have been analyzed for copy number variation. Surprisingly, the same genetic abnormalities were found in cohorts of patients affected with mental retardation, autism, or schizophrenia. © 2010 Faculty of 1000 Ltd.

Poletti A.,University of Antwerp
British Journal of Politics and International Relations | Year: 2010

The existing literature on the EU's participation in the agricultural negotiations of the Doha Round assumes that EU policy-makers develop autonomous preferences in favour of liberalising agricultural trade, thus going against the preferences of the agricultural sector. This article challenges this view and argues that WTO judicialisation-the strengthened enforcement of rules introduced with the creation of the WTO-affects the domestic politics of trade in WTO members. My key contention is that WTO judicialisation confronts societal interests and public authorities with legal vulnerability, and that this elicits a willingness to co-operate with other WTO members and thus pre-empt foreign challenges to domestic policies. Empirically, the article shows that negotiations centred on offsetting the potentially disruptive effects of foreign legal challenges to EU farm policies. © 2010 The Author. British Journal of Politics and International Relations © 2010 Political Studies Association.

Lam J.S.L.,Nanyang Technological University | van de voorde E.,University of Antwerp
Maritime Policy and Management | Year: 2011

Competition in the business world nowadays is largely between supply chains, rather than individual players only. The same situation exists in container shipping. The study looks into container shipping from an integrated perspective and investigates the nature and level of supply chain integration in container shipping. Based on empirical examinations of the world's top 30 container shipping lines, a scenario analysis is conducted. The paper aims to present the scenario analysis for examining supply chain integration in container shipping. It also aims to formulate strategic recommendations for liners to create and sustain competitive advantage. The scenario analysis is designed to allow more complete consideration of alternative possible outcomes and their implications on the research topic. It involves an evaluation of past and present events and provides a plausible discussion of what might occur in the future. It depicts four scenarios of supply chain integration in container shipping, namely, low integration, partner-focused integration, activity-focused integration and high integration. On the whole, research findings suggest that market situations favour those scenarios representing higher level of supply chain integration. Importantly, with reference to the scenario analysis, shipping lines should position themselves in an appropriate scenario and formulate strategic plans accordingly. © 2011 Copyright Taylor and Francis Group, LLC.

Bhandari V.,National Institute of Technology Tiruchirappalli | Sundar S.,Banaras Hindu University | Dujardin J.C.,Institute of Tropical Medicine | Dujardin J.C.,University of Antwerp | Salotra P.,National Institute of Technology Tiruchirappalli
Antimicrobial Agents and Chemotherapy | Year: 2014

Leishmania donoVani is the causative agent of the potentially fatal disease visceral leishmaniasis (VL). Chemotherapeutic options available to treat VL are limited and often face parasite resistance, inconsistent efficacy, and toxic side effects. Paromomycin (PMM) was recently introduced to treat VL as a monotherapy and in combination therapy. It is vital to unDerstand the mechanisms of PMM resistance to safeguard the drug. In the present study, we utilized experimentally generated PMM-resistant L. donoVani to elucidate the mechanisms of resistance and parasite biology. We found increased membrane fluidity accompanied by decreased intracellular drug accumulation in the PMM-resistant parasites. There were marked increases in gene expression of ATP-binding cassette (ABC) transporters (MDR1 and MRPA) and protein phosphatase 2A that evince increased drug efflux. Further, evaluation of parasite tolerance toward host leishmanicidal mechanisms revealed PMM-resistant parasites as being more tolerant to nitrosative stress at the promastigote and amastigote stages. The PMM-resistant parasites also predicted a better survival capacity, as indicated by resistance to complement-mediated lysis and increased stimulation of host interleukin-10 (IL-10) expression. The susceptibilities of PMM-resistant isolates to other antileishmanial agents (sodium antimony gluconate and miltefosine) remained unchanged. The data implicated the roles of altered membrane fluidity, decreased drug accumulation, increased expression of ABC transporters, and greater tolerance of parasites to host defense mechanisms in conferring PMM resistance in Leishmania. Copyright © 2014, American Society for Microbiology.