Zuletzt publiziert

  • Working Paper

    Zur symbolischen Kastration von traditionellen Männlichkeiten 

    Schwanke, Julia
    Göttinger Centrum für Geschlechterforschung: Göttingen, 2017
    Die österreichische Schriftstellerin Elfriede Jelinek (*1946) gilt als Autorin, die durch die überspitzte Darstellung der männlichen Herrschaft patriarchale Herrschaftsformen kritisiert. Der vorliegende Beitrag analysiert zwei Romane Jelineks der 1980er Jahre aus gendertheoretischer Sicht: Die Ausgesperr-ten und Die Klavierspielerin. Es wird gezeigt, dass Jelinek über eine einfache Patriarchatskritik hinaus-geht, indem sie die männliche Herrschaft ad absurdum führt – sie führt symbolisch kastrierte Männ-lichkeiten als Persiflage einer traditionellen Männlichkeit vor. Für die Analyse werden soziologische geschlechts- und klassentheoretische Ansätze mit einer Methode zur Figurenanalyse verbunden. Mi-chael Meusers Ansatz, welcher Raewyn Connells Konzept der hegemonialen Männlichkeit mit Pierre Bourdieus Habitus-Konzept verbindet, wird in die Figurenanalyse Jens Eders integriert. Dadurch wird die Performanz von Männlichkeit in Jelineks Prosa sichtbar(er) gemacht und in den Kontext ei-ner doppelten Distinktions- und Dominanzlogik eingeordnet. Im Zuge der Analyse wird deutlich, dass die männlichen Figuren, welche sich bei der Konstruktion ihrer Männlichkeit am Ideal der he-gemonialen Männlichkeit orientieren, zum Scheitern verurteilt sind. Sie können den Anforderungen, die das Patriarchat mit der Verkörperung einer hegemonialen Männlichkeit an sie stellt, nicht gerecht werden. Jelinek kastriert sie symbolisch.
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  • Zeitschriftenartikel

    Levels and trends of childhood undernutrition by wealth and education according to a Composite Index of Anthropometric Failure: evidence from 146 Demographic and Health Surveys from 39 countries 

    Vollmer, Sebastian; Harttgen, Kenneth; Kupka, Roland; Subramanian, S. V.
    BMJ Global Health 2017; 2(2): Art. e000206
    Background Governments have endorsed global targets to reduce childhood undernutrition as part of the Sustainable Development Goals. Understanding the socioeconomic differences in childhood undernutrition has the potential to be helpful for targeting policy to reach these goals. Methods We specify a logistic regression model with the Composite Index of Anthropometric Failure (CIAF) as the outcome and indicator variables for wealth quartiles, maternal education categories and a set of covariates as explanatory variables. Wealth and education variables are interacted with a period indicator for 1990–2000 compared with 2001–2014 to observe differences over time. Based on these regressions we calculate predicted CIAF prevalence by wealth and education categories and over time. Results The sample included 146 surveys from 39 low-income and lower-middle-income countries with an overall sample size of 533 217 children. CIAF prevalence was 47.5% in 1990–2000, and it declined to 42.6% in 2001–2014. In 1990–2000 the CIAF prevalence of children with mothers with less than primary education was 31 percentage points higher than for mothers with secondary or higher education. This difference slightly decreased to 27 percentage points in 2001–2014. The difference in predicted CIAF prevalence of children from the highest and lowest wealth quartiles was 21 percentage points and did not change over time. Conclusions We find evidence for persistent and even increasing socioeconomic inequalities in childhood undernutrition, which underlines the importance of previous calls for equity-driven approaches targeting the most vulnerable to reduce childhood malnutrition.
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  • Zeitschriftenartikel

    Breakdown of local information processing may underlie isoflurane anesthesia effects. 

    Wollstadt, Patricia; Sellers, Kristin K; Rudelt, Lucas; Priesemann, Viola; Hutt, Axel; Fröhlich, Flavio; Wibral, Michael
    PLoS computational biology 2017-06; 13(6): Art. e1005511
    The disruption of coupling between brain areas has been suggested as the mechanism underlying loss of consciousness in anesthesia. This hypothesis has been tested previously by measuring the information transfer between brain areas, and by taking reduced information transfer as a proxy for decoupling. Yet, information transfer is a function of the amount of information available in the information source-such that transfer decreases even for unchanged coupling when less source information is available. Therefore, we reconsidered past interpretations of reduced information transfer as a sign of decoupling, and asked whether impaired local information processing leads to a loss of information transfer. An important prediction of this alternative hypothesis is that changes in locally available information (signal entropy) should be at least as pronounced as changes in information transfer. We tested this prediction by recording local field potentials in two ferrets after administration of isoflurane in concentrations of 0.0%, 0.5%, and 1.0%. We found strong decreases in the source entropy under isoflurane in area V1 and the prefrontal cortex (PFC)-as predicted by our alternative hypothesis. The decrease in source entropy was stronger in PFC compared to V1. Information transfer between V1 and PFC was reduced bidirectionally, but with a stronger decrease from PFC to V1. This links the stronger decrease in information transfer to the stronger decrease in source entropy-suggesting reduced source entropy reduces information transfer. This conclusion fits the observation that the synaptic targets of isoflurane are located in local cortical circuits rather than on the synapses formed by interareal axonal projections. Thus, changes in information transfer under isoflurane seem to be a consequence of changes in local processing more than of decoupling between brain areas. We suggest that source entropy changes must be considered whenever interpreting changes in information transfer as decoupling.
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  • Zeitschriftenartikel

    What makes a reach movement effortful? Physical effort discounting supports common minimization principles in decision making and motor control. 

    Morel, Pierre; Ulbrich, Philipp; Gail, Alexander
    PLoS biology 2017-06; 15(6): Art. e2001323
    When deciding between alternative options, a rational agent chooses on the basis of the desirability of each outcome, including associated costs. As different options typically result in different actions, the effort associated with each action is an essential cost parameter. How do humans discount physical effort when deciding between movements? We used an action-selection task to characterize how subjective effort depends on the parameters of arm transport movements and controlled for potential confounding factors such as delay discounting and performance. First, by repeatedly asking subjects to choose between 2 arm movements of different amplitudes or durations, performed against different levels of force, we identified parameter combinations that subjects experienced as identical in effort (isoeffort curves). Movements with a long duration were judged more effortful than short-duration movements against the same force, while movement amplitudes did not influence effort. Biomechanics of the movements also affected effort, as movements towards the body midline were preferred to movements away from it. Second, by introducing movement repetitions, we further determined that the cost function for choosing between effortful movements had a quadratic relationship with force, while choices were made on the basis of the logarithm of these costs. Our results show that effort-based action selection during reaching cannot easily be explained by metabolic costs. Instead, force-loaded reaches, a widely occurring natural behavior, imposed an effort cost for decision making similar to cost functions in motor control. Our results thereby support the idea that motor control and economic choice are governed by partly overlapping optimization principles.
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  • Zeitschriftenartikel

    Working Memory Requires a Combination of Transient and Attractor-Dominated Dynamics to Process Unreliably Timed Inputs. 

    Nachstedt, Timo; Tetzlaff, Christian
    Scientific reports 2017-05-30; 7(1): Art. 2473
    Working memory stores and processes information received as a stream of continuously incoming stimuli. This requires accurate sequencing and it remains puzzling how this can be reliably achieved by the neuronal system as our perceptual inputs show a high degree of temporal variability. One hypothesis is that accurate timing is achieved by purely transient neuronal dynamics; by contrast a second hypothesis states that the underlying network dynamics are dominated by attractor states. In this study, we resolve this contradiction by theoretically investigating the performance of the system using stimuli with differently accurate timing. Interestingly, only the combination of attractor and transient dynamics enables the network to perform with a low error rate. Further analysis reveals that the transient dynamics of the system are used to process information, while the attractor states store it. The interaction between both types of dynamics yields experimentally testable predictions and we show that this way the system can reliably interact with a timing-unreliable Hebbian-network representing long-term memory. Thus, this study provides a potential solution to the long-standing problem of the basic neuronal dynamics underlying working memory.
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  • Zeitschriftenartikel

    Panya: Economies of Deception and the Discontinuities of Indentured Labour Recruitment and the Slave Trade, Nigeria and Fernando Pó, 1890s–1940s 

    Martino, Enrique
    African Economic History 2016; 44(1) p.91-129
    In the first half of the twentieth century, most of Fernando Pó’s contract workers came from societies in southeastern Nigeria which had been heavily impacted by the transatlantic and internal slave trades. These contract workers were recruited by a new generation of labor recruiters, dispatched covertly by Spanish imperial employers, through a form of kidnapping known as panya. Panya was the largest labor smuggling and trafficking network in colonial West Africa, bringing tens of thousands of migrants to long and obligatory contracts on Fernando Pó. In contrast to scholars who have interpreted this history as a holdover from the pre-colonial period, this article argues that panya arose from the contractual order of Spanish imperial rule. Extensive archival research reveals the voices of those caught in the warp of post-abolition colonial labor regimes, in order to rethink the passage from the pre-colonial slave trade to imperialism within West African history. Using a series of vivid and precise petitions submitted by those who found themselves on the island of Fernando Pó, the article shows how these sources contain the potential to reconceptualize the disjunctures between enslavement in the slave trade and the recruitment of contract labor.
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  • Zeitschriftenartikel

    Dash-peonage: the contradictions of debt bondage in the colonial plantations of Fernando Pó 

    Martino, Enrique
    Africa 2017; 87(1) p.53-78
    Dash in pidgin English means an ancillary gift to an exchange. What happened when the dash became attached to the indentured labour contracts that the Spanish Empire brought from Cuba to their last colony, Spanish Guinea? On the island of Fernando Pó, which came to be almost wholly populated by Nigerian labour migrants, the conditional gift in the form of a large wage advance produced a particularly intense contradiction. In the historiography of unfree labour, the excess wage advance is thought to create conditions for the perpetuation of bondage through debt. However, in imperial contexts, the wage advance did not generate compliance and immobility; exactly the opposite – it produced unprecedented waves of further escalation and dispersed flight. The dash was pushed up by workers themselves and relayed by informal recruiters. Together they turned this lynchpin of indentured labour and debt peonage into a counter-practice that almost led to the collapse of the plantations in the 1950s. The trajectories of the dash led to a more pointed version of the foundational thesis of global labour history: namely, that it was actually free labour, not unfree labour, that was incompatible with labour scarcity-ridden imperial capitalism.
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  • Zeitschriftenartikel

    Analysis of the lipid body proteome of the oleaginous alga Lobosphaera incisa 

    Siegler, Heike; Valerius, Oliver; Ischebeck, Till; Popko, Jennifer; Tourasse, Nicolas J; Vallon, Olivier; Khozin-Goldberg, Inna; Braus, Gerhard H; Feussner, Ivo
    BMC Plant Biology 2017; 17(1): Art. 98
    Abstract Background Lobosphaera incisa (L. incisa) is an oleaginous microalga that stores triacylglycerol (TAG) rich in arachidonic acid in lipid bodies (LBs). This organelle is gaining attention in algal research, since evidence is accumulating that proteins attached to its surface fulfill important functions in TAG storage and metabolism. Results Here, the composition of the LB proteome in L incisa was investigated by comparing different cell fractions in a semiquantitative proteomics approach. After applying stringent filters to the proteomics data in order to remove contaminating proteins from the list of possible LB proteins (LBPs), heterologous expression of candidate proteins in tobacco pollen tubes, allowed us to confirm 3 true LBPs: A member of the algal Major Lipid Droplet Protein family, a small protein of unknown function and a putative lipase. In addition, a TAG lipase that belongs to the SUGAR DEPENDENT 1 family of TAG lipases known from oilseed plants was identified. Its activity was verified by functional complementation of an Arabidopsis thaliana mutant lacking the major seed TAG lipases. Conclusions Here we describe 3 LBPs as well as a TAG lipase from the oleaginous microalga L. incisa and discuss their possible involvement in LB metabolism. This study highlights the importance of filtering LB proteome datasets and verifying the subcellular localization one by one, so that contaminating proteins can be recognized as such. Our dataset can serve as a valuable resource in the identification of additional LBPs, shedding more light on the intriguing roles of LBs in microalgae.
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  • Monografie

    Energieeffizienz in Klein- und Kleinstunternehmen des Handwerks 

    Runst, Petrik; Bettendorf, Axel
    Volkswirtschaftliches Institut für Mittelstand und Handwerk an der Universität Göttingen: Göttingen, 2017
    Die vorliegende Kurzstudie zur betrieblichen Energieeffizienz greift auf Daten zurück, welche in einer gemeinsamen Umfrage der Handwerkskammern Trier, Düsseldorf, Saarbrücken, Koblenz, Hamburg und Münster erhoben worden sind. Sie basiert auf Antworten von 203 Handwerksunternehmen. Es wurde gezeigt, dass für das Thema Energieeffizienz vorrangig der/die Inhaber/in verantwortlich ist. Über die Hälfte der Befragten kennen ihre Energiekosten; bei größeren Unternehmen steigt der Anteil auf über 75 %. Die Verantwortlichen informieren sich hauptsächlich über niedrigschwellige Angebote, wie Energieversorger, Herstellerangaben oder das Internet. Gebäudesanierungen stellen die häufigste Energieeffizienzmaßnahme (EEM) dar. Das Wissen über die eigenen Energiekosten hat einen Einfluss darauf, ob das Unternehmen überhaupt im EEM-Bereich aktiv wird. Es gibt außerdem einen Zusammenhang zwischen Immobilienbesitz und der Durchführung von EEMs, welcher auf die Existenz eines Mieter- Vermieter-Dilemmas hindeutet. Die Gründe für eine Nicht-Durchführung von EEMs sind hauptsächlich wirtschaftlicher Natur (mangelnde Rentabilität bzw. lange Amortisationszeiten). Es scheint hier auch ein Zusammenhang mit dem demografischen Wandel zu bestehen; Betriebsnachfolgeprobleme werden häufig als Grund für die Nicht-Umsetzung von EEMs angegeben. Außerdem geben die Unternehmen an, dass das Thema Energieeffizienz für sie wenig relevant ist, was sich durch den geringen Energiekostenanteil an den Gesamtkosten erklären könnte. Wenn EEMs durchgeführt werden, geschieht dies häufig im Zusammenhang mit Ersatz-Investitionen oder durch den Wunsch nach Werterhalt, selten aber durch betriebswirtschaftliches Kalkül oder eine ökologische Ausrichtung des Unternehmens. Die Nutzung von Fördermitteln, Energieberatern und Energiemanagement-Systemen sind stark von der Unternehmensgröße abhängig. Für die beiden erstgenannten Themen kann vermutet werden, dass der bürokratische Aufwand den Nutzen oft übersteigt.
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  • Zeitschriftenartikel

    Subsampling scaling 

    Levina, A.; Priesemann, V.
    Nature Communications 2017; 8: Art. 15140
    In real-world applications, observations are often constrained to a small fraction of a system. Such spatial subsampling can be caused by the inaccessibility or the sheer size of the system, and cannot be overcome by longer sampling. Spatial subsampling can strongly bias inferences about a system’s aggregated properties. To overcome the bias, we derive analytically a subsampling scaling framework that is applicable to different observables, including distributions of neuronal avalanches, of number of people infected during an epidemic outbreak, and of node degrees. We demonstrate how to infer the correct distributions of the underlying full system, how to apply it to distinguish critical from subcritical systems, and how to disentangle subsampling and finite size effects. Lastly, we apply subsampling scaling to neuronal avalanche models and to recordings from developing neural networks. We show that only mature, but not young networks follow power-law scaling, indicating self-organization to criticality during development.
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  • Zeitschriftenartikel

    The effect of hypoxia on the lipidome of recombinant Pichia pastoris 

    Adelantado, Núria; Tarazona, Pablo; Grillitsch, Karlheinz; García-Ortega, Xavier; Monforte, Sergi; Valero, Francisco; Feussner, Ivo; Daum, Günther; Ferrer, Pau
    Microbial Cell Factories 2017; 16(1): Art. 86
    Abstract Background Cultivation of recombinant Pichia pastoris (Komagataella sp.) under hypoxic conditions has a strong positive effect on specific productivity when the glycolytic GAP promoter is used for recombinant protein expression, mainly due to upregulation of glycolytic conditions. In addition, transcriptomic analyses of hypoxic P. pastoris pointed out important regulation of lipid metabolism and unfolded protein response (UPR). Notably, UPR that plays a role in the regulation of lipid metabolism, amino acid metabolism and protein secretion, was found to be upregulated under hypoxia. Results To improve our understanding of the interplay between lipid metabolism, UPR and protein secretion, the lipidome of a P. pastoris strain producing an antibody fragment was studied under hypoxic conditions. Furthermore, lipid composition analyses were combined with previously available transcriptomic datasets to further understand the impact of hypoxia on lipid metabolism. Chemostat cultures operated under glucose-limiting conditions under normoxic and hypoxic conditions were analyzed in terms of intra/extracellular product distribution and lipid composition. Integrated analysis of lipidome and transcriptome datasets allowed us to demonstrate an important remodeling of the lipid metabolism under limited oxygen availability. Additionally, cells with reduced amounts of ergosterol through fluconazole treatment were also included in the study to observe the impact on protein secretion and its lipid composition. Conclusions Our results show that cells adjust their membrane composition in response to oxygen limitation mainly by changing their sterol and sphingolipid composition. Although fluconazole treatment results a different lipidome profile than hypoxia, both conditions result in higher recombinant protein secretion levels.
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  • Working Paper

    (Wie) Die O-Phase verändern? 

    Volpers, Simon; Brodersen, Folke
    Göttinger Centrum für Geschlechterforschung: Göttingen, 2017
    Basierend auf qualitativen Erhebungen (teilnehmende Beobachtung, themenzentriert-narratives Inter-view) in den‚ Orientierungsphasen der Studienfächer Physik, Wirtschaftswissenschaften und Sozialwissenschaften werden Göttinger Praxen studentischer Hochschuleinführung rekonstruiert. Diese erfahren in öffentlich-medialen wie hochschulinternen Diskursen eine zunehmende Kritik. Der Beitrag folgt den sich andeutenden Diskursbewegungen, die auf Basis der strukturellen Eigenlogiken der sog. O-Phase verortet und kontrastiert werden. Erörtert werden eine Grundstruktur des Exzesses, darin eingebettete, gewaltförmige vergeschlechtlichte und sexualisierte Praxen sowie die Funktionalität und Anschlussfähigkeit dieser Form des Studieneinstiegs innerhalb gegenwärtiger Transformationen der Hochschule. Der Beitrag entwickelt eine empirisch fundierte Perspektivierung, Zusammenführung und Reformulierung von Kritik.
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  • Zeitschriftenartikel

    Fast Dynamical Coupling Enhances Frequency Adaptation of Oscillators for Robotic Locomotion Control 

    Nachstedt, Timo; Tetzlaff, Christian; Manoonpong, Poramate
    Frontiers in Neurorobotics 2017; 11: Art. 14
    Rhythmic neural signals serve as basis of many brain processes, in particular of locomotion control and generation of rhythmic movements. It has been found that specific neural circuits, named central pattern generators (CPGs), are able to autonomously produce such rhythmic activities. In order to tune, shape and coordinate the produced rhythmic activity, CPGs require sensory feedback, i.e., external signals. Nonlinear oscillators are a standard model of CPGs and are used in various robotic applications. A special class of nonlinear oscillators are adaptive frequency oscillators (AFOs). AFOs are able to adapt their frequency toward the frequency of an external periodic signal and to keep this learned frequency once the external signal vanishes. AFOs have been successfully used, for instance, for resonant tuning of robotic locomotion control. However, the choice of parameters for a standard AFO is characterized by a trade-off between the speed of the adaptation and its precision and, additionally, is strongly dependent on the range of frequencies the AFO is confronted with. As a result, AFOs are typically tuned such that they require a comparably long time for their adaptation. To overcome the problem, here, we improve the standard AFO by introducing a novel adaptation mechanism based on dynamical coupling strengths. The dynamical adaptation mechanism enhances both the speed and precision of the frequency adaptation. In contrast to standard AFOs, in this system, the interplay of dynamics on short and long time scales enables fast as well as precise adaptation of the oscillator for a wide range of frequencies. Amongst others, a very natural implementation of this mechanism is in terms of neural networks. The proposed system enables robotic applications which require fast retuning of locomotion control in order to react to environmental changes or conditions.
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  • Zeitschriftenartikel

    Gender bias in scholarly peer review 

    Helmer, Markus; Schottdorf, Manuel; Neef, Andreas; Battaglia, Demian
    eLife 2017; 6: Art. 21718
    Peer review is the cornerstone of scholarly publishing and it is essential that peer reviewers are appointed on the basis of their expertise alone. However, it is difficult to check for any bias in the peer-review process because the identity of peer reviewers generally remains confidential. Here, using public information about the identities of 9000 editors and 43000 reviewers from the Frontiers series of journals, we show that women are underrepresented in the peer-review process, that editors of both genders operate with substantial same-gender preference (homophily), and that the mechanisms of this homophily are gender-dependent. We also show that homophily will persist even if numerical parity between genders is reached, highlighting the need for increased efforts to combat subtler forms of gender bias in scholarly publishing.
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  • Zeitschriftenartikel

    Structural insights into the mechanism of the DEAH-box RNA helicase Prp43 

    Tauchert, Marcel J.; Fourmann, Jean-Baptiste; Lührmann, Reinhard; Ficner, Ralf
    eLife 2017; 6: Art. e21510
    The DEAH-box helicase Prp43 is a key player in pre-mRNA splicing as well as the maturation of rRNAs. The exact modus operandi of Prp43 and of all other spliceosomal DEAH-box RNA helicases is still elusive. Here, we report crystal structures of Prp43 complexes in different functional states and the analysis of structure-based mutants providing insights into the unwinding and loading mechanism of RNAs. The Prp43.ATP-analog.RNA complex shows the localization of the RNA inside a tunnel formed by the two RecA-like and C-terminal domains. In the ATP-bound state this tunnel can be transformed into a groove prone for RNA binding by large rearrangements of the C-terminal domains. Several conformational changes between the ATP- and ADP-bound states explain the coupling of ATP hydrolysis to RNA translocation, mainly mediated by a b-turn of the RecA1 domain containing the newly identified RF motif. This mechanism is clearly different to those of other RNA helicases.
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  • Zeitschriftenartikel

    Bulk isolation of basidiospores from wild mushrooms by electrostatic attraction with low risk of microbial contaminations 

    Lakkireddy, Kiran; Kües, Ursula
    AMB Express 2017; 7(1): Art. 28
    The basidiospores of most Agaricomycetes are ballistospores. They are propelled off from their basidia at maturity when Buller’s drop develops at high humidity at the hilar spore appendix and fuses with a liquid film formed on the adaxial side of the spore. Spores are catapulted into the free air space between hymenia and fall then out of the mushroom’s cap by gravity. Here we show for 66 different species that ballistospores from mushrooms can be attracted against gravity to electrostatic charged plastic surfaces. Charges on basidiospores can influence this effect. We used this feature to selectively collect basidiospores in sterile plastic Petri-dish lids from mushrooms which were positioned upside-down onto wet paper tissues for spore release into the air. Bulks of 104 to >107 spores were obtained overnight in the plastic lids above the reversed fruiting bodies, between 104 and 106 spores already after 2–4 h incubation. In plating tests on agar medium, we rarely observed in the harvested spore solutions contaminations by other fungi (mostly none to up to in 10% of samples in different test series) and infrequently by bacteria (in between 0 and 22% of samples of test series) which could mostly be suppressed by bactericides. We thus show that it is possible to obtain clean basidiospore samples from wild mushrooms. The technique of spore collection through electrostatic attraction in plastic lids is applicable to fresh lamellate and poroid fruiting bodies from the wild, to shortlived deliquescent mushrooms, to older and dehydrating fleshy fruiting bodies, even to animal-infested mushrooms and also to dry specimens of long-lasting tough species such as Schizophyllum commune.
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  • Monografie

    Vor- und Nachteile des Meisterbriefs im Vergleich zu freiwilligen Qualifikationszertifikaten 

    Lankau, Matthias; Müller, Klaus
    Volkswirtschaftliches Institut für Mittelstand und Handwerk an der Universität Göttingen: Göttingen, 2017
    Im Falle handwerklicher Produkte und Dienstleistungen des Baugewerbes handelt es sich um sogenannte Vertrauensgüter, da ein (Laien-)Kunde ihre Qualität auch nach dem Kauf meist nur schwer beurteilen kann. Ohne ein geeignetes Regulierungsinstrument birgt diese Asymmetrie in der Verteilung der Qualitätsinformation zu Lasten des Kunden die Gefahr des Versagens des Markts für hohe Qualität und damit die Gefährdung von Konsumenten. Das Ziel dieser Kurzstudie ist es, zu erörtern, ob die derzeitige Regulierung des A-Handwerks im Baugewerbe in Form des Meistervorbehalts durch ein Alternativinstrument ersetzt werden könnte, ohne dass der Markt für hohe Qualität versagt und Konsumenten gefährdet werden. Zurzeit muss jeder Leiter eines Betriebs des A-Handwerks über die Qualifikation eines Meisters oder einem als gleichwertig betrachteten Äquivalent verfügen. Durch die hohe Qualifikation der Handwerker erhöht sich tendenziell auch die Qualität der Produkte und Dienstleistungen im gesamten Markt der A-Handwerke. Demzufolge verringert sich das Problem des Marktversagens aufgrund asymmetrisch verteilter Qualitätsinformationen, da jeder Kunde auf ein Mindestmaß an Qualifikation und demzufolge Qualität vertrauen kann. Darüber hinaus wird ein Mindestmaß an Verbraucherschutz durch die Abwehr potenzieller Gefahren von den Konsumenten erreicht. Ein Nachteil, den der Meistervorbehalt in den A-Handwerken mit sich bringt, ist, dass hierdurch Anbieter mit niedrigen Qualifikationen keinen Zugang zum Markt der A-Handwerke haben. Hierdurch fehlt es strukturell an Angeboten im Niederpreissegment, wodurch jene Konsumentenschicht benachteiligt wird, die niedrige Qualität zu günstigen Preisen nachfragt. Durch freiwillige Qualifikationszertifikate könnte sich der Handwerksmarkt unter bestimmten Umständen, die diese Studie näher erläutert, in Hochpreissegmente für höhere Qualität sowie in Niederpreissegmente teilen. Die Analyse zeigt jedoch, dass dies Konsumentengefährdungen nicht ausschließt. Gerade im Niederpreissegment haben Handwerker nur geringe Anreize, in ihre Qualifikation zu investieren. Somit steigen hier die Wahrscheinlichkeit schlechter Dienstleistungsqualität sowie das Potenzial der Gefährdung der Konsumenten. Alles in allem lässt sich hieraus folgern, dass freiwillige Zertifizierungen nur in den Branchen des Handwerks eine Alternative zum Meisterbrief sein könnten, in denen Konsumentengefährdungen auszuschließen sind. Darüber hinaus gilt es hier jedoch genau zu überprüfen, ob die Abschaffung des Meistervorbehalts nicht weitere Regulierungsziele, wie die Sicherstellung der hohen Ausbildungsleistung des Handwerks, kompromittieren würde.
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  • Zeitschriftenartikel

    Enhanced Locomotion Efficiency of a Bio-inspired Walking Robot using Contact Surfaces with Frictional Anisotropy 

    Manoonpong, Poramate; Petersen, Dennis; Kovalev, Alexander; Wörgötter, Florentin; Gorb, Stanislav N.; Spinner, Marlene; Heepe, Lars
    Scientific Reports 2016; 6: Art. 39455
    Based on the principles of morphological computation, we propose a novel approach that exploits the interaction between a passive anisotropic scale-like material (e.g., shark skin) and a non-smooth substrate to enhance locomotion efficiency of a robot walking on inclines. Real robot experiments show that passive tribologically-enhanced surfaces of the robot belly or foot allow the robot to grip on specific surfaces and move effectively with reduced energy consumption. Supplementing the robot experiments, we investigated tribological properties of the shark skin as well as its mechanical stability. It shows high frictional anisotropy due to an array of sloped denticles. The orientation of the denticles to the underlying collagenous material also strongly influences their mechanical interlocking with the substrate. This study not only opens up a new way of achieving energy-efficient legged robot locomotion but also provides a better understanding of the functionalities and mechanical properties of anisotropic surfaces. That understanding will assist developing new types of material for other realworld applications.
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  • Monografie

    Integration von Flüchtlingen durch Ausbildung im Handwerk - Potenziale, Herausforderungen und Erfolgsfaktoren 

    Lahner, Jörg
    Volkswirtschaftliches Institut für Mittelstand und Handwerk an der Universität Göttingen: Göttingen, 2017
    Die Integration von Migrantinnen und Migranten, speziell von Flüchtlingen, stellt eine der großen gesellschaftlichen Herausforderungen in Deutschland dar. Parallel dazu fällt es dem deutschen Handwerk immer schwerer, seinen Fachkräftebedarf zu decken. Eine wachsende Zahl an Projekten von Bund und Ländern versucht deshalb, gezielt die Ausbildung von Flüchtlingen im Handwerk zu fördern. Dabei zeigt diese Untersuchung, dass es potenziell eine Vielzahl interessierter Betriebe und motivierter Flüchtlinge mit Affinität zu einem Handwerksberuf gibt. Zudem sind die Handwerkskammern mit ihren Bildungszentren und ihren vielfältigen Erfahrungen im Bereich zielgruppenspezifischer Angebote für eine effektive Unterstützung bestens aufgestellt. Allerdings ist der Ausbildungserfolg von zahlreichen Faktoren abhängig. Erstens gilt es, die Voraussetzungen der Flüchtlinge, vor allem die sprachlichen, gründlich zu prüfen. Die Integration in den Betrieb, der Besuch der Berufsschule, Herausforderungen der persönlichen Lebenssituation (Familienverantwortung, Unterbringung etc.) sind nicht nur für Flüchtlinge kritische Faktoren des Ausbildungserfolges, Flüchtlinge haben hier jedoch häufig besondere Hürden zu meistern. Deshalb ist eine intensive sozialpädagogische Betreuung vor und während der Ausbildung in der Regel unverzichtbar. Auch wenn der vorliegende Beitrag lediglich auf der gutachterlichen Prüfung eines einzelnen Pilotprojektes fußt, lassen sich durchaus vielfältige Erkenntnisse sowohl für die Praxis als auch für die Förderpolitik ableiten. Insgesamt zeigt sich, dass die spezifischen Hindernisse in vielen Fällen überwindbar sind und Ausbildung von Flüchtlingen im Handwerk gelingen kann. Damit eröffnet sich für geneigte und gut vorbereitete Flüchtlinge eine echte Perspektive gesellschaftlicher Integration. Für das Handwerk selbst ergibt sich eine neue Option der Nachwuchssicherung, sofern eine qualifizierte Unterstützung gesichert ist und alle Beteiligten über hinreichend Geduld und Motivation verfügen.
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    Neurons in Primate Visual Cortex Alternate between Responses to Multiple Stimuli in Their Receptive Field 

    Li, Kang; Kozyrev, Vladislav; Kyllingsbæk, Søren; Treue, Stefan; Ditlevsen, Susanne; Bundesen, Claus
    Frontiers in Computational Neuroscience 2016; 10: Art. 141
    A fundamental question concerning representation of the visual world in our brain is how a cortical cell responds when presented with more than a single stimulus. We find supportive evidence that most cells presented with a pair of stimuli respond predominantly to one stimulus at a time, rather than a weighted average response. Traditionally, the firing rate is assumed to be a weighted average of the firing rates to the individual stimuli (response-averaging model) (Bundesen et al., 2005). Here, we also evaluate a probability-mixing model (Bundesen et al., 2005), where neurons temporally multiplex the responses to the individual stimuli. This provides a mechanism by which the representational identity of multiple stimuli in complex visual scenes can be maintained despite the large receptive fields in higher extrastriate visual cortex in primates. We compare the two models through analysis of data from single cells in the middle temporal visual area (MT) of rhesus monkeys when presented with two separate stimuli inside their receptive field with attention directed to one of the two stimuli or outside the receptive field. The spike trains were modeled by stochastic point processes, including memory effects of past spikes and attentional effects, and statistical model selection between the two models was performed by information theoretic measures as well as the predictive accuracy of the models. As an auxiliary measure, we also tested for uni- or multimodality in interspike interval distributions, and performed a correlation analysis of simultaneously recorded pairs of neurons, to evaluate population behavior.
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