225 research outputs found

    Modeling potential masking of echolocating sperm whales exposed to continuous 1–2 kHz naval sonar

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    This study was sponsored by the U.S. Living Marine Resources program, Office of Naval Research (ONR) Grant Nos. N00014-18-1-2062 and N00014-20-1-2709, UK Defence Science and Technology Laboratory (DSTL), French Direction générale de l'armement (DGA), and the Netherlands Ministry of Defence.Modern active sonar systems can (almost) continuously transmit and receive sound, which can lead to more masking of important sounds for marine mammals than conventional pulsed sonar systems transmitting at a much lower duty cycle. This study investigated the potential of 1–2 kHz active sonar to mask echolocation-based foraging of sperm whales by modeling their echolocation detection process. Continuous masking for an echolocating sperm whale facing a sonar was predicted for sonar sound pressure levels of 160 dB re 1 μPa2, with intermittent masking at levels of 120 dB re 1 μPa2, but model predictions strongly depended on the animal orientation, harmonic content of the sonar, click source level, and target strength of the prey. The masking model predicted lower masking potential of buzz clicks compared to regular clicks, even though the energy source level is much lower. For buzz clicks, the lower source level is compensated for by the reduced two-way propagation loss to nearby prey during buzzes. These results help to predict what types of behavioral changes could indicate masking in the wild. Several key knowledge gaps related to masking potential of sonar in echolocating odontocetes were identified that require further investigation to assess the significance of masking.Publisher PDFPeer reviewe

    A rapid assessment framework for food system shocks: lessons learned from COVID-19 in the Indo-Pacific region

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    The frequency and severity of shocks to food systems is accelerating globally, exemplified by the current COVID-19 outbreak. In low- and middle-income countries, the impacts have exacerbated existing food system vulnerabilities and poverty. Governments and donors must respond quickly, but few tools are available that identify interventions to build food system resilience, or emerging opportunities for transformation. In this paper we reflect on the application of a systems-based rapid assessment which we applied across 11 Indo-Pacific countries in May-July 2020. Our approach was shaped by three design parameters: the integration of key informants’ perspectives engaged remotely within the countries, applicability to diverse food systems and COVID-19 experiences across the region, and the consideration of food systems as complex systems. For the rapid assessment we adopted an analytical framework proposed by Allen and Prosperi (2016). To include a development lens, we added the analysis of vulnerable groups and their exposure, impacts, recovery potential and resilience, and pro-poor interventions. We concluded that the framework and approach facilitated integration and triangulation of disparate knowledge types and data to identify priority interventions and was sufficiently flexible to be applied across food systems, at both national, sub-national and commodity scales. The step-wise method was simple and enabled structured inquiry and reporting. Although the systems concepts appeared more easily transferrable to key informants in some countries than others, potentially transformational interventions were identified, and also some risks of maladaptation. We present a refined framework that emphasises analysis of political, economic and institutional drivers of exposure and vulnerability, the constraints that they pose for building recovery potential and resilience, and trade-offs amongst winners and losers inherent in proposed interventions

    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

    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

    Superior induction and maintenance of protective CD8 T cells in mice infected with mouse cytomegalovirus vector expressing RAE-1 

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    Due to a unique pattern of CD8 T-cell response induced by cytomegaloviruses (CMVs), live attenuated CMVs are attractive candidates for vaccine vectors for a number of clinically relevant infections and tumors. NKG2D is one of the most important activating NK cell receptors that plays a role in costimulation of CD8 T cells. Here we demonstrate that the expression of CD8 T-cell epitope of Listeria monocytogenes by a recombinant mouse CMV (MCMV) expressing the NKG2D ligand retinoic acid early-inducible protein 1-gamma (RAE-1γ) dramatically enhanced the effectiveness and longevity of epitope-specific CD8 T-cell response and conferred protection against a subsequent challenge infection with Listeria monocytogenes. Unexpectedly, theattenuatedgrowth in vivo of the CMV vector expressing RAE-1γ and its capacity to enhance specific CD8 T-cell response were preserved even in mice lacking NKG2D, implying additional immune function for RAE-1γ beyond engagement of NKG2D. Thus, vectors expressing RAE-1γ represent a promising approach in the development of CD8 T-cell– based vaccine

    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

    Routine human papillomavirus genotyping by DNA sequencing in community hospital laboratories

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    <p>Abstract</p> <p>Background</p> <p>Human papillomavirus (HPV) genotyping is important for following up patients with persistent HPV infection and for evaluation of prevention strategy for the individual patients to be immunized with type-specific HPV vaccines. The aim of this study was to optimize a robust "low-temperature" (LoTemp™) PCR system to streamline the research protocols for HPV DNA nested PCR-amplification followed by genotyping with direct DNA sequencing. The protocol optimization facilitates transferring this molecular technology into clinical laboratory practice. In particular, lowering the temperature by 10°C at each step of thermocycling during <it>in vitro </it>DNA amplification yields more homogeneous PCR products. With this protocol, template purification before enzymatic cycle primer extensions is no longer necessary.</p> <p>Results</p> <p>The HPV genomic DNA extracted from liquid-based alcohol-preserved cervicovaginal cells was first amplified by the consensus MY09/MY11 primer pair followed by nested PCR with GP5+/GP6+ primers. The 150 bp nested PCR products were subjected to direct DNA sequencing. The hypervariable 34–50 bp DNA sequence downstream of the GP5+ primer site was compared to the known HPV DNA sequences stored in the GenBank using on-line BLAST for genotyping. The LoTemp™ ready-to-use PCR polymerase reagents proved to be stable at room temperature for at least 6 weeks. Nested PCR detected 107 isolates of HPV in 513 cervicovaginal clinical samples, all validated by DNA sequencing. HPV-16 was the most prevalent genotype constituting 29 of 107 positive cases (27.2%), followed by HPV-56 (8.5%). For comparison, Digene HC2 test detected 62.6% of the 107 HPV isolates and returned 11 (37.9%) of the 29 HPV-16 positive cases as "positive for high-risk HPV".</p> <p>Conclusion</p> <p>The LoTemp™ ready-to-use PCR polymerase system which allows thermocycling at 85°C for denaturing, 40°C for annealing and 65°C for primer extension can be adapted for target HPV DNA amplification by nested PCR and for preparation of clinical materials for genotyping by direct DNA sequencing. HPV genotyping is performed by on-line BLAST algorithm of a hypervariable L1 region. The DNA sequence is included in each report to the physician for comparison in following up patients with persistent HPV infection, a recognized tumor promoter in cancer induction.</p

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

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

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