38 research outputs found

    The role of moisture in the nest thermoregulation of social wasps

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    Paper nests of social wasps are intriguing constructions for both, biologists and engineers. We demonstrate that moisture and latent heat significantly influence the thermal performance of the nest construction. Two colonies of the hornet Vespa crabro were investigated in order to clarify the relation of the temperature and the moisture regime inside the nest. Next to fairly stable nest temperatures the hornets maintain a high relative humidity inside the nest. We found that in consequence a partial vapor-pressure gradient between nest and ambient drives a constant vapor flux through the envelope. The vapor flux is limited by the diffusion resistance of the envelope. The driving force of vapor flux is heat, which is consumed through evaporation inside the nest. The colony has to compensate this loss with metabolic heat production in order to maintain a stable nest temperature. However, humidity fluctuations inside the nest induce circadian adsorption and desorption cycles, which stabilize the nest temperature and thus contribute significantly to temperature homeostasis. Our study demonstrates that both mechanisms influence nest thermoregulation and need to be considered to understand the thermodynamic behavior of nests of wasps and social insects in genera

    Phagocytosis and digestion of pH-sensitive fluorescent dye (Eos-FP) transfected E. coli in whole blood assays from patients with severe sepsis and septic shock

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    The function of phagocytic and antigen presenting cells is of crucial importance to sustain immune competence against infectious agents as well as malignancies. We here describe a reproducible procedure for the quantification of phagocytosis by leukocytes in whole blood. For this, a pH-sensitive green-fluorescent protein- (GFP) like dye (Eos-FP) is transfected into infectious microroganisms. After UV-irradiation, the transfected bacteria emit green (≈5160 nm) and red (≈581 nm) fluorescent light at 490 nm excitation. Since the red fluorescent light is sensitive to acidic pH, the phagocytosed bacteria stop emitting red fluorescent light as soon as the phagosomes fuse with lysosomes. The green fluorescence is maintained in the phagolysosome until pathogen degradation is completed. Fluorescence emission can be followed by flow cytometry with filter settings documenting fluorescence 1 (FL 1, FITC) and fluorescence 2 (FL 2, phycoerythrin, PE). Eos-FP transfected bacteria can also be traced within phagocytes using microscopical techniques. A standardized assay has been developed which is suitable for clinical studies by providing clinicians with syringes pre-filled with fixed and appropriately UV-irradiated Eos-FP E. coli (TruCulture™). After adding blood or body fluids to these containers and starting the incubation at 37°C, phagocytosis by granulocytes proceeds over time. Cultures can be terminated at a given time by lysing red blood cells followed by flow cytometry. A pilot study demonstrated that Eos-FP E. coli phagocytosis and digestion was up-regulated in the majority of patients with either severe sepsis or septic shock as compared to healthy donors (p < 0.0001 after o/n incubation). Following treatment with recombinant human granulocyte colony-stimulating factor (rhG-CSF) in selected patients with sepsis, phagolysosome fusion appeared to be accelerated

    Measurement of Angular Coefficients of BˉDνˉ\bar{B} \to D^* \ell \bar{\nu}_\ell: Implications for Vcb|V_{cb}| and Tests of Lepton Flavor Universality

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    We measure the complete set of angular coefficients JiJ_i for exclusive BˉDνˉ\bar{B} \to D^* \ell \bar{\nu}_\ell decays (=e,μ\ell = e, \mu). Our analysis uses the full 711fb1711\,\mathrm{fb}^{-1} Belle data set with hadronic tag-side reconstruction. The results allow us to extract the form factors describing the BDB \to D^* transition and the Cabibbo-Kobayashi-Maskawa matrix element Vcb|V_{\rm cb}|. Using recent lattice QCD calculations for the hadronic form factors, we find Vcb=(41.0±0.7)×103|V_{\rm cb}| = (41.0 \pm 0.7) \times 10^3 using the BGL parameterization, compatible with determinations from inclusive semileptonic decays. We search for lepton flavor universality violation as a function of the hadronic recoil parameter ww, and investigate the differences of the electron and muon angular distributions. We find no deviation from Standard Model expectations

    The role of moisture in the nest thermoregulation of social wasps

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    ISSN:1432-1904ISSN:0028-104

    INTERNAL FRICTION AND ELASTIC CONSTANT ANOMALIES OF ANTIFERROMAGNETIC Mn-Ni ALLOYS

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    Les variations du module élastique et du coefficient de frottement interne avec la température ont été mesurés sur des alliages poly- et mono-cristallins de Mn-Ni dans le domaine de concentration 14 à 30 %. Les alliages riches en Mn montrent de grandes anomalies à la température de Néel et au-dessous accompagnées d'un frottement interne élevé avec Q-1max ≈ 10-2. Ces anomalies sont dues aux transformations magnétiques et/ou structurales se produisant dans ces alliages.The temperature variation of the elastic module, as well as of the internal friction of poly- and single crystalline Mn-Ni alloys in the concentration range 14 - 30% Ni is reported. Mn-rich alloys exhibit large elastic anomalies at and below the Néel temperature and a high internal friction with Q-1max ≈ 10-2. These anomalies are due to the magnetic and/or structural transformations occurring in these alloys

    Zur Bedeutung der Listen bekannt gemachter Mittel und Verfahren für behördlich angeordnete Entseuchungen, Entwesungen und zur Bekämpfung von Wirbeltieren auf Grundlage des § 18 Infektionsschutzgesetz

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    Zum Schutz des Menschen vor übertragbaren Krankheiten dürfen bei behördlich angeordneten Entseuchungen (Desinfektion), Entwesungen (Bekämpfung von Gliedertieren) und Maßnahmen zur Bekämpfung von Wirbeltieren, durch die Krankheitserreger verbreitet werden können, nur Mittel und Verfahren verwendet werden, die von der zuständigen Bundesoberbehörde in einer Liste im Bundesgesundheitsblatt bekannt gemacht worden sind. Die Aufnahme in die Liste erfolgt nur, wenn die Mittel und Verfahren hinreichend wirksam sind und keine unvertretbaren Auswirkungen auf Gesundheit und Umwelt haben (§ 18 IFSG). Für Hersteller von Desinfektionsmitteln und Schädlingsbekämpfungsmitteln besteht keine Verpflichtung, ihre Präparate in die Listen nach § 18 IfSG eintragen zu lassen. Insbesondere ist die Eintragung in die Listen keine Voraussetzung für den Marktzugang in Deutschland. Dem Anwender steht die Wahl des Mittels grundsätzlich frei, soweit es sich nicht um behördlich angeordnete Maßnahmen, d. h. Entseuchungen, Entwesungen oder Maßnahmen gegen Wirbeltiere gemäß § 17 IfSG handelt. Es ist jedoch dringend zu empfehlen, auch bei routinemäßiger Anwendung die oben genannten Listen zu Rate zu ziehen, da bei den dort aufgeführten Mitteln und Verfahren die Wirksamkeit durch behördliche, teilweise im Rahmen von Akkreditierungen qualitätsgesicherten Prüfungen oder Sachverständigengutachten belegt und von unabhängigen Institutionen bestätigt wurde.In order to protect human health against communicable diseases, the German Protection against Infection Act (IfSG) requires the use of officially approved products and methods for officially ordered disinfection, disinfestation (control of arthropods) as well as measures for the management of vertebrate pests that spread pathogens. Official approval is granted by registration in lists published by the responsible federal health authorities and only for products and methods that have been tested and found to be sufficiently effective and do not have an unacceptable impact on health and the environment (§ 18 IfSG). It is not compulsory for manufacturers to have their products and methods listed in accordance with § 18 IfSG. In particular listing is not a prerequisite for access to the German market. Users are free to choose a product as long as no officially ordered measure, i.e. disinfection, disinfestation or measures against vertebrate pests, according to § 18 IfSG applies. However, it is highly recommended to use approved products included in the abovementioned lists even for routine application, as these registered products and methods have been tested, i.e. the efficacy has been proven by means of specific, recognized and quality assured testing procedures or by expert reports which have been confirmed by independent institutions
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