211 research outputs found

    First indications that northern bottlenose whales are sensitive to behavioural disturbance from anthropogenic noise

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    -Although northern bottlenose whales were the most heavily hunted beaked whale, we have little information about this species in its remote habitat of the North Atlantic Ocean. Underwater anthropogenic noise and disruption of their natural habitat may be major threats, given the sensitivity of other beaked whales to such noise disturbance. We attached dataloggers to 13 northern bottlenose whales and compared their natural sounds and movements to those of one individual exposed to escalating levels of 1–2 kHz upsweep naval sonar signals. At a received sound pressure level (SPL) of 98 dB re 1 μPa, the whale turned to approach the sound source, but at a received SPL of 107 dB re 1 μPa, the whale began moving in an unusually straight course and then made a near 180° turn away from the source, and performed the longest and deepest dive (94 min, 2339 m) recorded for this species. Animal movement parameters differed significantly from baseline for more than 7 h until the tag fell off 33–36 km away. No clicks were emitted during the response period, indicating cessation of normal echolocation-based foraging. A sharp decline in both acoustic and visual detections of conspecifics after exposure suggests other whales in the area responded similarly. Though more data are needed, our results indicate high sensitivity of this species to acoustic disturbance, with consequent risk from marine industrialization and naval activity

    Pro-Apoptotic Protein Noxa Regulates Memory T Cell Population Size and Protects against Lethal Immunopathology

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    Memory T cells form a highly specific defense layer against reinfection with previously encountered pathogens. In addition, memory T cells provide protection against pathogens that are similar, but not identical to the original infectious agent. This is because each T cell response harbors multiple clones with slightly different affinities, thereby creating T cell memory with a certain degree of diversity. Currently, the mechanisms that control size, diversity, and cross-reactivity of the memory T cell pool are incompletely defined. Previously, we established a role for apoptosis, mediated by the BH3-only protein Noxa, in controlling diversity of the effector T cell population. This function might positively or negatively impact T cell memory in terms of function, pool size, and cross-reactivity during recall responses. Therefore, we investigated the role of Noxa in T cell memory during acute and chronic infections. Upon influenza infection, Noxa−/− mice generate a memory compartment of increased size and clonal diversity. Reinfection resulted in an increased recall response, whereas cross-reactive responses were impaired. Chronic infection of Noxa−/− mice with mouse CMV resulted in enhanced memory cell inflation, but no obvious pathology. In contrast, in a model of continuous, high-level T cell activation, reduced apoptosis of activated T cells rapidly led to severe organ pathology and premature death in Noxa-deficient mice. These results establish Noxa as an important regulator of the number of memory cells formed during infection. Chronic immune activation in the absence of Noxa leads to excessive accumulation of primed cells, which may result in severe pathology

    De verdeelde samenleving

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    Tijdens het voorlopige hoogtepunt van de corona-uitbraak, in april, bleek dat een groot deel van de Nederlandse bevolking angstig en onzeker was. Bij de heropening van de samenleving begin juli was de angst en onzekerheid afgenomen, maar dat heeft zich niet doorgezet. Dit blijkt uit de bevindingen van het vervolgonderzoek De verdeelde samenleving. Er is weer sprake van een toename van angst- en stressgevoelens en een verdere afname in het vertrouwen in de overheid, het RIVM en de GGD. Jongeren en mensen met kwetsbare maatschappelijke posities, zoals een laag inkomen, een lage opleiding, geringe werkzekerheid, en een beperkt ondersteunend netwerk, hebben relatief meer onvrede over het overheidsbeleid dan groepen met een sterkere maatschappelijke positie en een sterker ondersteunend netwerk

    Performance of the CMS Cathode Strip Chambers with Cosmic Rays

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    The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

    Performance and Operation of the CMS Electromagnetic Calorimeter

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    The operation and general performance of the CMS electromagnetic calorimeter using cosmic-ray muons are described. These muons were recorded after the closure of the CMS detector in late 2008. The calorimeter is made of lead tungstate crystals and the overall status of the 75848 channels corresponding to the barrel and endcap detectors is reported. The stability of crucial operational parameters, such as high voltage, temperature and electronic noise, is summarised and the performance of the light monitoring system is presented

    CMS physics technical design report : Addendum on high density QCD with heavy ions

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    Peer reviewe

    Calibration of the CMS Drift Tube Chambers and Measurement of the Drift Velocity with Cosmic Rays

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    Peer reviewe

    Aligning the CMS Muon Chambers with the Muon Alignment System during an Extended Cosmic Ray Run

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    Peer reviewe
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