Carbon and nitrogen assimilation in the Bering Sea clams Nuculana radiata and Macoma moesta

We analyzed bulk carbon and nitrogen stable isotope values (delta C-13 and delta N-15) of the benthic clams Nuculana radiata and Macoma moesta from the Bering Sea during controlled feeding experiments (spring of 2009 and 2010) using isotopically labeled sea ice algae. The aim was to determine the ability of these clam species to assimilate carbon and nitrogen from sea ice algae. Specimens were collected in the Bering Sea and placed into jars without sediment (2009, N. radiata only) or into natural sediment cores (2010, both species). The clams were offered isotopically enriched (both C and N) or non-enriched algal feeds for time periods of 42 (2009) and 18 d (2010). Isotopic assimilation rates for carbon and nitrogen were calculated using the change in the isotope ratios of the clams over the experimental time. N. radiata in the jar experiments had slow isotopic assimilation rates (0.01 to 0.23 parts per thousand d(-1)), with solvent-extractable organic matter/lipids taking up both of the isotope markers fastest and muscle tissue the slowest. Lipids may thus be particularly suitable to track the immediate ingestion of sea ice algal production in benthic consumers. M. moesta showed 30% higher isotopic assimilation compared to N. radiata in sediment cores, likely reflecting the different feeding behaviors of these two species. Based on our results, N. radiata is likely better able to utilize food sources buried in the sediment and may be more competitive over the sediment surface feeding M. moesta under conditions of reduced ice algal production in the northern Bering Sea. (C) 2012 Elsevier B.V. All rights reserved.This project was undertaken as a part of the National Science Foundation funded Bering Sea Ecosystem Study (BEST Project) #0732767awarded to R. Gradinger, K. Iken, and B. Bluhm at the University of Alaska Fairbanks. Additional research funding to J. Weems was provided by the UAF Center for Global Change Student Research Grant with funds from the Cooperative Institute for Alaska Research and the Harland and Genevieve Emerson Foundation of Adel, Iowa. Bering Sea field support and operations in 2009 and 2010 were provided by chief scientists L. Cooper, J. Grebmeier, and C. Ashjian, and the vessels and crews of the United States Coast Guard Cutters Healy and Polar Sea. Additionally, field and laboratory aid was provided by B. Bluhm, M. Kaufman, B. McConnell, M. Schuster, and J. von Meltzer. Services rendered by the Alaska Stable Isotope Facility and its staff, N. Haubenstock and T. Howe, were very much appreciated. Academic support for J. Weems was provided by the School of Fisheries and Ocean Sciences at the University of Alaska Fairbanks. We thank M. Castellini and two anonymous reviewers for comments on earlier versions of this manuscript. Support for the fatty acid analyses and partial support forWooller came from NSF grant ARC 0902177 awarded to (Gradinger, Iken and Wooller). [ST]Ye

Timing of Ice Algal Grazing by the Arctic Nearshore Benthic Amphipod Onisimus litoralis

Sea ice algae have been widely discussed as a potential food source for pelagic and benthic animals in ice-covered waters, specifically in the light of current substantial changes in the Arctic ice regime. Stomach and gut contents of the Arctic nearshore lysianassid amphipod Onisimus litoralissampled from February to May 2003 indicate that Arctic ice algae were dominant food no earlier than the onset of ice melt. Crustaceans, common prey in a previous study, were absent in stomachs and guts during the survey period. Our data support the concept that sea ice-derived organic carbon is of specific relevance for Arctic plankton and benthos during the period of ice melt.On a souvent discuté du fait que les algues de glace de mer pourraient être une source d'alimentation pour les animaux pélagiques et benthiques des eaux recouvertes de glace, surtout à la lumière des changements considérables qui caractérisent le régime de glaciation de l'Arctique. Le contenu de l'estomac et des intestins des amphipodes lysianassides Onisimus litoralisen proximité des rives de l'Arctique qui a été échantillonné de février à mai 2003 indique que les algues de glace de l'Arctique étaient dominantes pas plus tôt qu'au moment de la fonte des glaces. Les crustacés, qui étaient une proie courante dans le cadre d'une étude antérieure, ne se retrouvaient pas dans les estomacs et les intestins des animaux au cours de la période d'échantillonnage. Nos données viennent soutenir le concept selon lequel le carbone organique dérivé de la glace de mer revêt une importance particulière pour le plancton de l'Arctique et le benthos pendant la période de la fonte des glaces

A Multiscale Thermo-Fluid Computational Model for a Two-Phase Cooling System

In this paper, we describe a mathematical model and a numerical simulation method for the condenser component of a novel two-phase thermosyphon cooling system for power electronics applications. The condenser consists of a set of roll-bonded vertically mounted fins among which air flows by either natural or forced convection. In order to deepen the understanding of the mechanisms that determine the performance of the condenser and to facilitate the further optimization of its industrial design, a multiscale approach is developed to reduce as much as possible the complexity of the simulation code while maintaining reasonable predictive accuracy. To this end, heat diffusion in the fins and its convective transport in air are modeled as 2D processes while the flow of the two-phase coolant within the fins is modeled as a 1D network of pipes. For the numerical solution of the resulting equations, a Dual Mixed-Finite Volume scheme with Exponential Fitting stabilization is used for 2D heat diffusion and convection while a Primal Mixed Finite Element discretization method with upwind stabilization is used for the 1D coolant flow. The mathematical model and the numerical method are validated through extensive simulations of realistic device structures which prove to be in excellent agreement with available experimental data

Adolescents' digital career aspirations: Evidence for gendered pathways in a digital future

Introduction Computers and technology are still perceived as a male domain. As a result of this “digital gender gap” boys aspire careers in the information and communication technology (ICT) branches much more than girls. Guided by the situated expectancy-value theory of motivated behavioral choices, the present study aims to shed light on the predictors of digital career aspirations. Methods Self-report questionnaires were completed by 1018 Austrian adolescents (52.3% girls; 72% non-immigrants; Mage = 13.55, SDage = 0.88) attending 61 Grade 7 and 8 classes located in 17 vocational secondary schools between April and June 2019. Individual and class-level predictors of digital career aspirations were investigated with multilevel modeling. Results Hierarchical linear models revealed that boys, younger adolescents, and second-generation immigrant adolescents had higher levels of digital career aspirations compared to girls, older adolescents, and non-immigrants. Hours spend with the laptop per day, digital self-efficacy and media appraisal positively predicted digital career aspirations on the individual level, while a higher number of immigrants in the classes and higher levels of teacher discussions about media were significant positive predictors on the class level. The model explained 17% of the individual level and 52% of the class level variance. Cross-level interactions were nonsignificant. Conclusions These results have major implications for educational practice. Most importantly, educational interventions should enhance girls' digital self-efficacy believes and media appraisal. Furthermore, teachers should increase their discussion about digital media as they foster adolescents' digital career aspirations and might prevent future gender segregation in the ICT sector.publishedVersio

Die neue Grüne Revolution in Afrika.

Die Bekämpfung von weltweitem Hunger bildet ein wesentliches Ziel der internationalen Entwicklungspolitik. Zwei private US-amerikanische Stiftungen, die Rockefeller und die Bill-and-Melinda-Gates Stiftung, gründeten 2006 die „Alliance for a Green Revolution in Africa“(AGRA), welche in dieser Arbeit analysiert wird. Mithilfe diskursanalytischer Methoden wird die Organisation auf die dahinterstehenden Akteure, ihre Ziele, Programme und verwendeten Schlüsselbegriffe untersucht. Zudem werden die Ansätze AGRAs in einen entwicklungstheoretischen Diskurs eingeordnet. Die Rockefeller Stiftung war bereits während der ersten Grünen Revolution in Asien und Lateinamerika ab den 1950er Jahren ein wesentlicher Akteur. Ziel war es Ernteerträge zu erhöhen und so Ernährung zu sichern. Es wurden neue landwirtschaftliche Hochertragssorten eingeführt, sowie künstlicher Dünger und chemische Pestizide eingesetzt. Die Beurteilung dieses großangelegten Projekts ist ambivalent: Zwar konnten Erträge signifikant erhöht werden, allerdings wurden hohe soziale und ökologische Kosten verursacht. Die Organisation AGRA betont sich in einigen Punkten von der ersten Grünen Revolution zu unterscheiden, verfolgt aber im Wesentlichen den gleichen Ansatz: Ernteerträge durch den Einsatz von modernem Saatgut und Agrarinputs zu steigern. Kritik an AGRA gibt es bereits zahlreich und lässt sich in zwei große Bereiche einteilen: Einerseits wird AGRA als Fortsetzung der ersten Grünen Revolution ab den 1950er Jahren gesehen und befürchtet, dass sich soziale und ökologische Probleme in Afrika wiederholen werden. Andererseits wird die Einführung von gentechnisch verändertem Saatgut durch AGRA befürchtet. AGRAs Ansatz ist nur ein Weg, wie landwirtschaftliche Verbesserung in Afrika erreicht werden kann. Um zu zeigen, dass es auch alternative Projekte gibt, werden in der Arbeit einige agrarökologische Ansätze vorgestellt, die bereits erste Erfolge verzeichnen konnten. AGRA ist eine junge Organisation, der verschiedene Richtungen offen stehen. Die Analyse der Organisation in dieser Arbeit gibt Einblicke über die momentanen Standpunkte und ist als Teilergebnis in einem fortlaufenden Forschungsprozess zu sehe

The Essence of Functioning in Sleep Disorders

This doctoral project seeks to answer the question about the essence of functioning, disability and health in the lived experience of persons with any kind of primary sleep disorder. Its overall objective is the development of a first version of Core Sets of categories of the International Classification of Functioning, Disability and Health (ICF) in an evidence- and consensus-based process. To this end, four separate studies exploring different perspectives (researcher, clinical, patient, health professional) have been conducted and their results provided the evidence basis for selecting the relevant categories for the ICF Core Sets for Sleep Disorders during an international consensus conference. The doctoral thesis first-authored by the doctoral candidate therefore consists of five separate publications (1 Systematic Review, 2 Patient Studies, 1 Expert Survey, 1 Conference Results) that describe the different steps in the development process

First trait-based characterization of Arctic ice meiofauna taxa

Trait-based approaches connect the traits of species to ecosystem functions to estimate the functional diversity of communities and how they may respond to environmental change. For the first time, we compiled a traits matrix across 11 traits for 28 species of Arctic ice meiofauna, including Copepoda (Subclass), Nematoda (Phylum), Acoela (Order), Rotifera (Phylum), and Cnidaria (Phylum). Over 50 years of pan-Arctic literature were manually reviewed, and trait categories were assigned to enable future trait–function connections within the threatened ice-associated ecosystem. Approximately two-thirds of the traits data were found at the genus or species level, ranging from 44% for Nematoda to 100% for Cnidaria. Ice meiofauna were shown to possess advantageous adaptations to the brine channel network within sea ice, including a majority with small body widths < 200 μm, high body flexibility, and high temperature and salinity tolerance. Diets were found to be diverse outside of the algal bloom season, with most organisms transitioning to ciliate-, omnivore-, or detritus-based diets. Eight species of the studied taxa have only been recorded within sea ice, while the rest are found in a mixture of sympagic–pelagic–benthic habitats. Twelve of the ice meiofauna species have been found with all life stages present in sea ice. Body width, temperature tolerance, and salinity tolerance were identified as traits with the largest research gaps and suffered from low-resolution taxonomic data. Overall, the compiled data show the degree to which ice meiofauna are adapted to spending all or portions of their lives within the ice

Selbsttätigkeit und Bildung im integrativen Kindergarten

Das Ziel vorliegende Arbeit ist es, herauszufinden wie Sonderkindergartenpädagoginnen das Konzept der Selbsttätigkeit in der integrativen Alltagspraxis wahrnehmen. Der Zusammenhang von Bildung und Selbsttätigkeit wird im theoretischen Abschnitt diskutiert, ebenso wird die Sonderkindergartenpädagogik näher erläutert und auf die schwierigen Rahmenbedingungen hingewiesen. Mit 5 Kindergartenpädagoginnen wurden auf Basis eines Leitfaden Interviews geführt und die Auswertung erfolgte mittels qualitativen Inhaltsanalyse nach Mayring. Die Ergebnisse der Untersuchung deuten darauf hin, dass Probleme der Theorie bezüglich der Selbsttätigkeit sich auch in der pädagogischen Handlungspraxis widerspiegeln. Unsicherheiten der Sonderkindergartenpädagoginnen hinsichtlich des Begriffs der Selbsttätigkeit, aber auch Rahmenbedingungen denen die Pädagoginnen ausgesetzt sind, sind ausschlaggebend für die mangelnde Umsetzung der Selbsttätigkeit in der pädagogischen Alltagpraxis. Die Art und der Grad der Behinderung sind ausschlaggebend für die Möglichkeit die Selbsttätigkeit in der Praxis pädagogischen Handelns zu unterstützen.The aim of this diploma thesis is to examine how nursery teachers in special needs education perceive the concept of self-direction within their integrative everyday practice. In the theoretical part the relation between education (Bildung) and the concept of self-direction is discussed as well as the principles of special needs education and the problem of surrounding conditions. Guided interviews were held with five nursery teachers and the transcripts were analyzed on the basis of qualitative content analysis. The results of the empirical research indicate that problems concerning the theory as well as the field of practice are perceptible. Crucial factors in the implementation of self-direction are the vagueness of the very concept in collaboration with the surrounding conditions faced by the nursery teachers within their everyday practice. The nature and degree of challenge are also relevant factors for the potential to encourage self-direction