Van Den Boomen C.,University Utrecht |
Van Den Boomen C.,Helmholtz Institute |
Peters J.C.,Maastricht University |
Peters J.C.,Institute of the Royal Netherlands Academy of Arts and science KNAW
PLoS ONE | Year: 2017
Social interaction starts with perception of the world around you. This study investigated two fundamental issues regarding the development of discrimination of higher spatial frequencies, which are important building blocks of perception. Firstly, it mapped the typical developmental trajectory of higher spatial frequency discrimination. Secondly, it developed and validated a novel design that could be applied to improve atypically developed vision. Specifically, this study examined the effect of age and reward on task performance, practice effects, and motivation (i.e., number of trials completed) in a higher spatial frequency (reference frequency: 6 cycles per degree) discrimination task. We measured discrimination thresholds in children aged between 7 to 12 years and adults (N = 135). Reward was manipulated by presenting either positive reinforcement or punishment. Results showed a decrease in discrimination thresholds with age, thus revealing that higher spatial frequency discrimination continues to develop after 12 years of age. This development continues longer than previously shown for discrimination of lower spatial frequencies. Moreover, thresholds decreased during the run, indicating that discrimination abilities improved. Reward did not affect performance or improvement. However, in an additional group of 5-6 year-olds (N = 28) punishments resulted in the completion of fewer trials compared to reinforcements. In both reward conditions children aged 5-6 years completed only a fourth or half of the run (64 to 128 out of 254 trials) and were not motivated to continue. The design thus needs further adaptation before it can be applied to this age group. Children aged 7-12 years and adults completed the run, suggesting that the design is successful and motivating for children aged 7-12 years. This study thus presents developmental differences in higher spatial frequency discrimination thresholds. Furthermore, it presents a design that can be used in future developmental studies that require multiple stimulus presentations such as visual perceptual learning. Copyright: © 2017 van den Boomen, Peters. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Peters J.C.,Maastricht University |
Peters J.C.,Institute of the Royal Netherlands Academy of Arts and science KNAW |
van den Boomen C.,Helmholtz Institute |
van den Boomen C.,University Utrecht |
And 2 more authors.
Frontiers in Human Neuroscience | Year: 2017
Perception of visual stimuli improves with training, but improvements are specific for trained stimuli rendering the development of generic training programs challenging. It remains unknown to which extent training of low-level visual features transfers to high-level visual perception, and whether this is accompanied by neuroplastic changes. The current event-related potential (ERP) study showed that training-induced increased sensitivity to a low-level feature, namely low spatial frequency (LSF), alters neural processing of this feature in high-level visual stimuli. Specifically, neural activity related to face processing (N170), was decreased for low (trained) but not high (untrained) SF content in faces following LSF training. These novel results suggest that: (1) SF discrimination learning transfers from simple stimuli to complex objects; and that (2) training the use of specific SF information affects neural processing of facial information. These findings may open up a new avenue to improve face recognition skills in individuals with atypical SF processing, such as in cataract or Autism Spectrum Disorder (ASD). © 2017 Peters, van den Boomen and Kemner.
News Article | December 12, 2016
The news caught him by surprise: Jörg Vogel was busy preparing an urgent grant proposal he wants to submit with Deutsche Forschungsgemeinschaft (DFG). Just at this moment, an e-mail from the DFG arrived in his inbox, informing him that he would receive one of the Gottfried Wilhelm Leibniz Prizes 2017 worth 2.5 million euros. "I was flabbergasted," recalls the Würzburg professor for infection biology who was in Greifswald when he learned about the good news. On Thursday afternoon he held two lectures there: one at the university and the other at the Alfried Krupp Wissenschaftskolleg. So there where probably enough people present to congratulate him after the news of his top-notch recognition had made the rounds. Since 2009, Professor Vogel has been the director of the Institute for Molecular Infection Biology (IMIB) of the Julius-Maximilians-Universität (JMU) Würzburg in Bavaria, Germany, and spokesman of the Research Center for Infectious Diseases (ZINF). Moreover, he is the founding director of the Helmholtz Institute for RNA-based Infection Research (HIRI) which the Helmholtz Association will establish at the JMU. The Leibniz laureate studies small regulatory RNA molecules of bacterial pathogens such as salmonella. He and his team are determined to get to the bottom of how these molecules work and act. His work could show new ways to fight pathogens. "With Jörg Vogel, the award recognizes one of the world's leading researchers in the field of RNA biology," as a DFG press release puts it, stating further that he is given the prize for his seminal contribution to understanding regulatory RNA molecules in infection biology. According to the DFG, Vogel detected the importance of RNA biochemistry very early on. Moreover, he has done pioneering work in the field of RNA analysis with the application and development of high-throughput sequencing methods. Jörg Vogel was born in Cottbus in 1967. He studied biochemistry at the Humboldt University in Berlin and at the Imperial College in London where he received his PhD in 1999. Following time in Sweden and Israel as a postdoc, he returned to Berlin in 2004 to lead a research group at the Max Planck Institute for Infection Biology. In 2009, he relocated to the University of Würzburg to become a Professor for Molecular Infection Biology. Vogel has already received numerous awards for his research activities. Among others, he is an elected member of the European Molecular Biology Organization EMBO, the National Academy of Sciences (Leopoldina) and both the American and European Academy of Microbiology. The Leibniz Prize will be handed to Vogel during a festive ceremony in Berlin on 15 March 2017. He can use the prize money for his research as he sees fit. In the 2017 awarding process, the DFG picked 10 scientists out of 134 proposed candidates. Vogel is one of two winners from Bavaria. Since 1986, the DFG has awarded the Leibniz Prize to scientists who, at an early stage of their careers, have demonstrated superior achievements in their research areas and who show exceptional promise for future top-level accomplishments that will have a sustainable impact on the German research landscape. The Würzburg winners of the Leibniz Prize So far, eleven scientists from the University of Würzburg have won one of the coveted Leibniz Prizes: Otto Ludwig Lange and Ulrich Heber (ecology/biochemistry/1986), Hans-Peter Zenner (ear, nose and throat medicine and cell biology/1987), Ingrid Grummt and Bert Hölldobler (molecular biology/zoology/1990), Martin Lohse (pharmacology/1999), Ulrich Konrad (musical sciences/2001), Thomas Mussweiler (psychology/2006), Holger Braunschweig (chemistry/2009), Laurens Molenkamp (physics/2014) and Dag Nikolaus Hasse (Philosophy/2016).
Klinge U.,RWTH Aachen |
Klinge U.,Helmholtz Institute |
Klink C.D.,RWTH Aachen |
Klosterhalfen B.,Institute For Pathologie
Zentralblatt fur Chirurgie - Zeitschrift fur Allgemeine, Viszeral- und Gefasschirurgie | Year: 2010
Modern meshes permit a radical treatment of hernias, an expectation that Billroth articulated already more than 100years ago. Because clinicaltrials are insufficient to evaluate the distinct effects of modified mesh materials in regard to tissue biocompatibility and functionality, a basic understanding of the physico-chemical properties is essential for a rational selection of the most appropriate device. Experimental data indicate that particularly the meshs porosity is of outstanding importance, resulting from the demanded tensile strength as well as the employed fibre material. Considering that different operation techniques require different mesh materials, specific requirements are discussed using the example of intraabdominal meshes, of parastomal meshes, of meshes in areas with bacterial contamination and of meshes in the hiatus region. Considering the late manifestation of some complications even after many years, any thorough quality control should include an assessment of explanted implant failures in addition to clinical experience. © Georg Thieme Verlag KG Stuttgart.
News Article | November 14, 2016
Copper and other non-ferrous metals cannot be fully broken down in mines, and residues of the valuable metals remain even after the metallurgical processes that follow. Residues are stored on tailings. The new German-Polish research project NOMECOR has two aims, namely to reclaim the metals as well as to make the mineral components of the tailings usable for cement production. The Federal Ministry for Research and Education is funding the research project for three years with approximately 500,000 euros. This is coordinated by the Helmholtz Institute Freiberg for Resource Technology (HIF) at the Helmholtz-Zentrum Dresden-Rossendorf as well as the Polish Institute for Non-ferrous Metallurgy (IMN). "The project intends to improve access to copper, a socio-economically important bulk metal," says project coordinator Dr Stefan Dirlich from the Freiberg Helmholtz Institute. Copper is expensive and in great demand, as it is used for electric wiring and machines, as well as for alloys such as brass or bronze. However, mining it is becoming increasingly difficult as the metal content in the ores is very low nowadays. The project is targeting several aims simultaneously as far as sustainability is concerned: greater resource efficiency by recycling the metals from tailings, and regaining natural areas by reducing tailings. The Karlsruhe Institute of Technology, the G.E.O.S. Ingenieurgesellschaft mbH and the Polish enterprise Hydrogeometal PK are also involved in the project. Bio-technicians working at the Helmholtz Institute want to use microorganisms to remove copper and other valuable metals from tailings. The research partners at IMN and GEOS intend to test the chemical methods for this. Furthermore, they will investigate how pure metals separate from dissolved copper ores and how further residues can be minimised. In this project, scientists from the Karlsruhe Institute of Technology want to investigate whether mineral tailing deposits are suitable for the production of cement. With this project, the Helmholtz Institute in Freiberg is enhancing its research into recycling reusable materials from mining waste sites. Apart from natural mineral deposits, these may become important secondary sources of raw materials in future, especially as there are tailings everywhere in the world where mining was or is carried out. The project partners want to work with sample materials from a flotation tank which is currently being developed in a Polish mine. All residues which result during the enrichment (flotation) of copper and other valuable metals to a metal concentrate are deposited in such pools. The residues eventually pile up in tailings; their volumes are many times greater than the amount of metal extracted. About 2.4 million tons of copper still remain in tailings of non-ferrous mines in Poland, which also includes copper. Only coal mines have a greater number of tailings. The kick-off for the NOMECOR research project recently took place in the Polish town of Poznan as part of the status seminar on STAIR - the programme for German-Polish research on sustainability. All funded programmes to date were introduced at this event. NOMECOR is part of the second round of funding and the only research project in the field of resource efficiency. The Helmholtz-Zentrum Dresden-Rossendorf (HZDR) conducts research in the sectors energy, health, and matter. The HZDR has been a member of the Helmholtz Association, Germany's largest research organization, since 2011. It has four locations (Dresden, Leipzig, Freiberg, Grenoble) and employs about 1,100 people - approximately 500 of whom are scientists, including 150 doctoral candidates. The Helmholtz Institute Freiberg for Resource Technology (HIF) pursues the objective of developing innovative technologies for the economy so that mineral and metalliferous raw materials can be made available and used more efficiently and recycled in an environmentally friendly manner. The HIF was founded in 2011, belongs to Helmholtz-Zentrum Dresden-Rossendorf and is cooperating closely with TU Bergakademie Freiberg.
van den Boomen C.,Helmholtz Institute |
van den Boomen C.,University Utrecht |
Lamme V.A.F.,University of Amsterdam |
Kemner C.,Helmholtz Institute |
Kemner C.,University Utrecht
Developmental Science | Year: 2014
Visual segmentation, a process in which elements are integrated into a form and segregated from the background, is known to differ from adults at infancy. The further developmental trajectory of this process, and of the underlying brain mechanisms, during childhood and adolescence is unknown. The aim of the study was to investigate the developmental trajectory of ERP reflections of visual segmentation, and to relate this to behavioural performance. One hundred and eleven typically developing children from 7 to 18 years of age were divided into six age groups. Each child performed two visual tasks. In a texture segmentation task, the difference in event-related potential (ERP) response to homogeneous (no visual segmentation) and checkered stimuli (visual segmentation) was investigated. In addition, behavioural performance on integration of elements into contours was measured. Both behavioural and ERP measurements of visual segmentation differed from adults in 7-12 year-old children. Behaviourally, young children were less able to integrate elements into a contour than older children. In addition, a developmental change was present in the ERP pattern evoked by homogeneous versus checkered stimuli. The largest differences in behaviour and ERPs were found between 7-8- and 9-10-, and between 11-12- and 13-14-year-old children, indicating the strongest development between those age groups. Behavioural as well as ERP measurements at 13-14 years of age showed similar results to those of adults. These results reveal that visual segmentation continues to develop until early puberty. Only by 13-14 years of age, children do integrate and segregate visual information as adults do. These results can be interpreted in terms of functional connectivity within the visual cortex. © 2013 John Wiley & Sons Ltd.
Paffen C.L.E.,University Utrecht |
Van der Stigchel S.,Helmholtz Institute
Attention, Perception, and Psychophysics | Year: 2010
Although it has been argued that visual attention and the dynamics of binocular rivalry are closely linked, strong evidence for this proposition is still lacking. Here, we investigate how perceptual alternations during binocular rivalry are affected by spatial attention by employing a cuing paradigm. We show a tight link between the occurrence of perceptual alternations and the spatiotemporal properties of visual attention: Alternations occurred earlier and more frequently at locations where visual attention was summoned by an exogenous cue. We argue that cuing a location where rival images are presented leads to a transient increase in the effective contrast of these rival images. This transient increase in effective contrast increases the probability of an alternation at that location. Furthermore, we suggest that an occipito-fronto-parietal network known to be involved in selective attention and binocular rivalry mediates perceptual alternations by boosting the neural response at attended locations. © 2010 The Psychonomic Society, Inc.
Graefe R.,Helmholtz Institute |
Henseler A.,ReinVAD GmbH |
Steinseifer U.,Helmholtz Institute
Artificial Organs | Year: 2016
Pump gaps are the most critical regions in a rotary blood pump when it comes to blood trauma in the form of hemolysis, protein destruction, and platelet activation. This study investigated six pump design parameters affecting the flow in a radial pump gap. A multivariate approach was employed to determine individual and quantitative parameter effects on blood trauma as well as parameter interactions. To consider the effect of shear stress and blood cell residence time, a validated numerical Lagrangian particle tracking approach was used. Based on the results, small-diameter pumps can be as blood compatible, if not more blood compatible, as large-diameter pumps as long as identical circumferential velocities and clearance gaps are maintained. Furthermore, the results indicate that an eccentric rotor position in the casing is not harmful and that a pressure difference generating washout flow and thereby reducing the cell residence time is of significant importance. © 2016 Wiley Periodicals, Inc. and International Center for Artificial Organs and Transplantation.
Kumar V.J.,Indian Institute of Technology Madras |
Blazek V.,Helmholtz Institute
2013 IEEE International Conference on Smart Instrumentation, Measurement and Applications, ICSIMA 2013 | Year: 2013
Photo-plethysmo-graphy (PPG) is a noninvasive method of obtaining a signal proportional to blood volume changes using light. From the initial trials seven decades back, the PPG technique has grown leaps and bounds and today its application has become indispensible not only during surgical procedures but also in patient monitoring in critical care environment. This paper traces the path of advancement of this technique and highlights the research outcomes of an "Indo German" collaborative research between Indian Institute of Technology Madras, Chennai, India and Technical University (RWTH) Aachen, Germany funded by ministry of science (BMBF), Germany, Research projects funded by Department of Science and Technology and Department of Biotechnology, Government of India. © 2013 IEEE.
Kappers A.M.L.,Helmholtz Institute |
Liefers B.J.,Helmholtz Institute
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012
Parallel in the outside world is not necessarily perceived as parallel. Previous studies have shown that what is felt as parallel can deviate significantly from what is physically parallel. In a new set-up, the influence of hand/arm orientation is investigated in detail by systematically varying the angle between the two hands, while the participants have to make a test bar parallel to a reference bar. Large positive deviations were found of about 32 % of the angle between the hands. The deviations were always in the direction of the rotation of the right hand with respect to the left hand. These findings are consistent with the hypothesis that the haptic perception of spatial relations is biased in the direction of the egocentric reference frame connected to the hand. © 2012 Springer-Verlag.