224 research outputs found

    BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models

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    Background: Quantitative models of biochemical and cellular systems are used to answer a variety of questions in the biological sciences. The number of published quantitative models is growing steadily thanks to increasing interest in the use of models as well as the development of improved software systems and the availability of better, cheaper computer hardware. To maximise the benefits of this growing body of models, the field needs centralised model repositories that will encourage, facilitate and promote model dissemination and reuse. Ideally, the models stored in these repositories should be extensively tested and encoded in community-supported and standardised formats. In addition, the models and their components should be cross-referenced with other resources in order to allow their unambiguous identification. Description: BioModels Database http://www.ebi.ac.uk/biomodels/ is aimed at addressing exactly these needs. It is a freely-accessible online resource for storing, viewing, retrieving, and analysing published, peer-reviewed quantitative models of biochemical and cellular systems. The structure and behaviour of each simulation model distributed by BioModels Database are thoroughly checked; in addition, model elements are annotated with terms from controlled vocabularies as well as linked to relevant data resources. Models can be examined online or downloaded in various formats. Reaction network diagrams generated from the models are also available in several formats. BioModels Database also provides features such as online simulation and the extraction of components from large scale models into smaller submodels. Finally, the system provides a range of web services that external software systems can use to access up-to-date data from the database. Conclusions: BioModels Database has become a recognised reference resource for systems biology. It is being used by the community in a variety of ways; for example, it is used to benchmark different simulation systems, and to study the clustering of models based upon their annotations. Model deposition to the database today is advised by several publishers of scientific journals. The models in BioModels Database are freely distributed and reusable; the underlying software infrastructure is also available from SourceForge https://sourceforge.net/projects/biomodels/ under the GNU General Public License

    Studium, Berufswahl und Berufstätigkeit: Nürnberger Sozialwirte zwischen 1981 und 1994

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    In dem Beitrag wird der berufliche Verbleib der Nürnberger Sozialwirte anhand einer Befragung der Absolventen von 1991 bis 1994 untersucht. Studiumsgestaltung, Berufssuche und Bewerbungsverhalten sowie Aspekte der ausgeübten Berufstätigkeit und Studiengangsevaluation werden erfaßt. Es wird festgestellt, daß die Übergangsphase zwischen Studiumsende und Aufnahme eines Berufs durch verschiedene kulturelle, institutionale, situationale und personale Faktoren beeinflußt ist. Mehr als die Hälfte der Befragten konnte trotz der Probleme auf dem Stellenmarkt für Akademiker ihre Arbeitsmarktchancen nutzen und geht einer geregelten Tätigkeit nach. Zufriedenheit wird sowohl hinsichtlich des Studiums als auch hinsichtlich der Beschäftigungssituation festgestellt. Insgesamt deutet die Studie auf die Vorteile der Kombination mit wirtschaftswissenschaftlichen Inhalten hin und unterstreicht die positive Wirkung von Berufspraktika für die Berufseinmündung. (ICA

    Treatment of Highland Frogs from the Two- Legged Stage with Homeopathically Prepared Thyroxin (10 -11 -10 -21 )

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    The influence of moderately diluted, agitated, i.e., homeopathically prepared, thyroxin solutions (10 -11 -10 -21 , final concentration in the basin water 0.6 × 10 -15 -0.6 × 10 -25 parts by weight after the first application) on metamorphosis in highland Rana temporaria from the two-legged stage was studied. In accordance with the homeopathic idea of effects of specially prepared dilutions being inverse to those of their mother substances, animals were treated either with thyroxin 10 -11 -10 -21 or analogously prepared blank solution (water). Development was monitored by documenting the number of animals that had entered the four-legged stage. It has been found that animals treated with the thyroxin solutions metamorphosed more slowly than the control animals, i.e., the effect of the homeopathically prepared thyroxin was opposed to the usual effect of molecular thyroxin. The number of test animals that reached the four-legged stage at defined points in time was smaller (2-13.5%) in the group treated with homeopathically prepared thyroxin at the points in time, compared to control. The results in this study sustain the previous multiresearcher findings that show that diluted homeopathically prepared thyroxin is able to slow down metamorphosis of R. temporaria

    Supplementary material from "Why are biting flies attracted to blue objects?"

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    Diurnal biting flies are strongly attracted to blue objects. This behaviour is widely exploited for fly control, but its functional significance is debated. It is hypothesized that blue objects resemble animal hosts; blue surfaces resemble shaded resting places and blue attraction is a by-product of attraction to polarized light. We computed the fly photoreceptor signals elicited by a large sample of leaf and animal integument reflectance spectra, viewed under open/cloudy illumination and under woodland shade. We then trained artificial neural networks (ANNs) to distinguish animals from leaf backgrounds, and shaded from unshaded surfaces, in order to find the optimal means of doing so based upon the sensory information available to a fly. After training, we challenged ANNs to classify blue objects used in fly control. Trained ANNs could make both discriminations with high accuracy. They discriminated animals from leaves based upon blue-green photoreceptor opponency and commonly misclassified blue objects as animals. Meanwhile, they discriminated shaded from unshaded stimuli using achromatic cues and never misclassified blue objects as shaded. We conclude that blue-green opponency is the most effective means of discriminating animals from leaf backgrounds using a fly's sensory information, and that blue objects resemble animal hosts through such mechanisms

    Coarse‐Grained Refractory Composite Castables Based on Alumina and Niobium

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    Niobium-alumina composite aggregates with 60 vol% metal content and with particle sizes up to 3150 μm are produced using castable technology followed by sintering, and a crushing and sieving process. X-Ray diffraction (XRD) analysis reveals phase separation during crushing as the niobium:corundum volume ratios is between 37:57 and 64:31 among the 4 produced aggregate classes 0–45, 45–500, 500–1000, and 1000–3150 μm. The synthesized aggregates are used to produce coarse-grained refractory composites in a second casting and sintering step. The fine- and coarse-grained material shows porosities between 32% and 36% with a determined cold modulus of rupture of 20 and 12 MPa, and E-moduli of 37 and 46 GPa, respectively. The synthesized fine-grained composites reached true strain values between 0.08 at 1100 °C and 0.18 at 1500 °C and the coarse-grained ones values between 0.02 and 0.09. The electrical conductivity for the fine-grained and the coarse-grained material is 448±66 and 111±25  S cm1^{−1}, respectively

    The Langmuir probe system in the Wendelstein 7-X test divertor

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    The design and evaluation of the Langmuir probe system used in the first divertor operation phase of Wendelstein 7-X is described. The probes are integrated into the target plates and have individually facetted surfaces to keep the angle of incidence of the magnetic field within an appropriate range for different magnetic configurations. Multiple models for the derivation of plasma parameters from current-voltage characteristics are introduced. These are analyzed with regard to their assumptions and limitations, generalized, and adapted to our use case. A detailed comparison is made to determine the most suitable model. It is found that the choice of model has a large impact, for example, resulting in a change in the inferred temperatures of up to a factor two. This evaluation is implemented in a Bayesian modeling framework and automated to allow for joint analysis with other diagnostics and a replacement of ad hoc assumptions. We rigorously treat parameter uncertainties, revealing strong correlations between them. General and flexible model formulations permit an expansion to additional effects

    Treatment of Lowland Frogs From the Spawn Stage with Homeopathically Prepared Thyroxin (10 -30

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    The influence of a highly diluted agitated, i.e. homeopathically prepared thyroxin solution (10-30, final concentration in the basin water 10-35 parts by weight after the first application) on metamorphosis in lowland Rana temporaria from the spawn stage on was studied. The treatment with homeopathically prepared thyroxin solution (10-30) starts at the frogspawn stage. It represents a tool to learn more about the previously standardized amphibian model, where the thyroxin solution was applied from the two- legged stage on only. Lowland frogs were pretreated by immersing spawn in an aqueous molecular thyroxin dilution (10-8 parts by weight). In later stages of development (2 to 4 legged), this has been found to speed up metamorphosis by around 15%. In accordance with the homeopathic idea of detoxication or cure, hyperstimulated animals (spawn or, in subsequence, larvae) were treated either with thyroxin that had been highly diluted and agitated in successive steps, i.e. homeopathically prepared (10-30), or analogously prepared blank solution (water). Development was monitored by documenting the number of animals that had entered the four-legged stage. It has been found that animals treated with the test solution metamorphosed more slowly than the control animals, i.e. the effect of the homeopathically prepared thyroxin was opposed to the usual effect of molecular thyroxin. The number of test animals that reached the 4- legged stage at defined points in time was slightly smaller in the group treated with homeopathically prepared thyroxin at some, but not at all points in time, compared to control. The results in this study sustain the previous multi researcher findings that highly diluted homeopathically prepared thyroxin is able to slow down metamorphosis of Rana temporaria

    Color change for Thermoregulation versus camouflage in free-ranging lizards

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    Animal coloration has multiple functions including thermoregulation,camouflage, and social signaling, and the requirementsof each function may sometimes conflict. Many terrestrial ectothermsaccommodate the multiple functions of color through color change.However, the relative importance of these functions and how colorchangingspecies accommodate themwhen they do conflict are poorlyunderstood because we lack data on color change in the wild. Here, weshow that the color of individual radio-tracked bearded dragon lizards,Pogona vitticeps, correlates strongly with background color andless strongly, but significantly, with temperature. We found no evidencethat individuals simultaneously optimize camouflage and thermoregulationby choosing light backgrounds when hot or dark backgroundswhen cold. In laboratory experiments, lizards showed both UV-visible(300–700 nm) and near-infrared (700–2,100 nm) reflectance changesin response to different background and temperature treatments, consistentwith camouflage and thermoregulatory functions, respectively,but with no interaction between the two. Overall, our results suggestthat wild bearded dragons change color to improve both thermoregulationand camouflage but predominantly adjust for camouflage, suggestingthat compromising camouflage may entail a greater potentialimmediate survival cost
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