659 research outputs found

    Prospects for studies of the free fall and gravitational quantum states of antimatter

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    Different experiments are ongoing to measure the effect of gravity on cold neutral antimatter atoms such as positronium, muonium and antihydrogen. Among those, the project GBAR in CERN aims to measure precisely the gravitational fall of ultracold antihydrogen atoms. In the ultracold regime, the interaction of antihydrogen atoms with a surface is governed by the phenomenon of quantum reflection which results in bouncing of antihydrogen atoms on matter surfaces. This allows the application of a filtering scheme to increase the precision of the free fall measurement. In the ultimate limit of smallest vertical velocities, antihydrogen atoms are settled in gravitational quantum states in close analogy to ultracold neutrons (UCNs). Positronium is another neutral system involving antimatter for which free fall under gravity is currently being investigated at UCL. Building on the experimental techniques under development for the free fall measurement, gravitational quantum states could also be observed in positronium. In this contribution, we review the status of the ongoing experiments and discuss the prospects of observing gravitational quantum states of antimatter and their implications.Comment: This work reviews contributions made at the GRANIT 2014 workshop on prospects for the observation of the free fall and gravitational quantum states of antimatte

    The value chain approach in one health: Conceptual framing and focus on present applications and challenges

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    The value chain (VC) is a major operational concept for socioeconomic analysis at meso level. Widely mobilized in development practice, it is still undergoing conceptual and practical refining, e.g., to take account of environmental and social sustainability. Briefly, VC refers to a system of value creation through the full set of actors, links, technical and commercial activities and flows involved in the provision of a good or service on a market. In the past decade, this concept has been promoted in the management of animal health. In particular, the emergence of highly pathogenic avian influenza (HPAI) has triggered an interdisciplinary dynamic including VC analysis as a central tool. These efforts promoted participatory investigation methods in the analysis of health systems. Using qualitative and quantitative data, these methods acknowledge the usefulness of actors' involvement and knowledge, hence facilitating the transdisciplinarity needed for effective action. They fit into adaptive and action-oriented strategies, fostering stakeholders' participation. Recent research on HPAI surveillance in South-East Asia merged VC and participatory approaches to develop innovative tools for analyzing constraints to information flow. On-going interventions for HPAI prevention and control as well as the prevention of other emerging zoonotic risks in Africa are presently building on this VC framework to develop strategies for its application at national and regional scales. Based on the latter experiences, this article proposes a field-based perspective on VC applications to animal and public health systems, within a One Health approach responding to the overall challenge of complexity

    Absolute proteomic quantification reveals design principles of sperm flagellar chemosensation

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    © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Troetschel, C., Hamzeh, H., Alvarez, L., Pascal, R., Lavryk, F., Boenigk, W., Koerschen, H. G., Mueller, A., Poetsch, A., Rennhack, A., Gui, L., Nicastro, D., Struenker, T., Seifert, R., & Kaupp, U. B. Absolute proteomic quantification reveals design principles of sperm flagellar chemosensation. Embo Journal, 39(4), (2020): e102723, doi:10.15252/embj.2019102723.Cilia serve as cellular antennae that translate sensory information into physiological responses. In the sperm flagellum, a single chemoattractant molecule can trigger a Ca2+ rise that controls motility. The mechanisms underlying such ultra‐sensitivity are ill‐defined. Here, we determine by mass spectrometry the copy number of nineteen chemosensory signaling proteins in sperm flagella from the sea urchin Arbacia punctulata. Proteins are up to 1,000‐fold more abundant than the free cellular messengers cAMP, cGMP, H+, and Ca2+. Opto‐chemical techniques show that high protein concentrations kinetically compartmentalize the flagellum: Within milliseconds, cGMP is relayed from the receptor guanylate cyclase to a cGMP‐gated channel that serves as a perfect chemo‐electrical transducer. cGMP is rapidly hydrolyzed, possibly via “substrate channeling” from the channel to the phosphodiesterase PDE5. The channel/PDE5 tandem encodes cGMP turnover rates rather than concentrations. The rate‐detection mechanism allows continuous stimulus sampling over a wide dynamic range. The textbook notion of signal amplification—few enzyme molecules process many messenger molecules—does not hold for sperm flagella. Instead, high protein concentrations ascertain messenger detection. Similar mechanisms may occur in other small compartments like primary cilia or dendritic spines.We thank Heike Krause for preparing the manuscript. Financial support by the Deutsche Forschungsgemeinschaft (DFG) via the priority program SPP 1726 “Microswimmers” and the Cluster of Excellence 1023 “ImmunoSensation” is gratefully acknowledged. We thank D. Stoddard for management of the UTSW cryo‐electron microscope facility, which is funded in part by a Cancer Prevention and Research Institute of Texas (CPRIT) Core Facility Award (RP170644). This study was supported by HHS|National Institutes of Health (NIH) grant R01 GM083122 and by CPRIT grant RR140082 to D. Nicastro

    Accurate and robust inference of genetic ancestry from cancer-derived molecular data across genomic platforms

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    Genetic ancestry-oriented cancer research requires the ability to perform accurate and robust ancestry inference from existing cancer-derived data, including whole exomes, transcriptomes and targeted gene panels, very often in the absence of matching cancer-free genomic data. In order to optimize and assess the performance of the ancestry inference for any given input cancer-derived molecular profile, we develop a data synthesis framework. In its core procedure, the ancestral background of the profiled patient is replaced with one of any number of individuals with known ancestry. Data synthesis is applicable to multiple profiling platforms and makes it possible to assess the performance of inference separately for each continental-level ancestry. This ability extends to all ancestries, including those without statistically sufficient representation in the existing cancer data. We further show that our inference procedure is accurate and robust in a wide range of sequencing depths. Testing our approach for three representative cancer types, and across three molecular profiling modalities, we demonstrate that global, continental-level ancestry of the patient can be inferred with high accuracy, as quantified by its agreement with the golden standard of the ancestry derived from matching cancer-free molecular data. Our study demonstrates that vast amounts of existing cancer-derived molecular data potentially are amenable to ancestry-oriented studies of the disease, without recourse to matching cancer-free genomes or patients’ self-identification by ancestry

    A Comparison of Professional Traders and Psychopaths in a Simulated Non-Zero Sum Game

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    In a prior study psychopathic individuals showed a diminished level of cooperativeness but realized higher individual rewards in a prisoner’s dilemma game, compared with community controls. The present study replicated this finding with professional bank traders, who exhibited less cooperative behavior than both of the aforermentioned groups (community controls and psychopathic patients). While the bank traders did not obtain a higher gain than the psychopathic individuals at an absolute level, they maximized the discrepancy between their own profit and the yield of their anonymous computerized gaming partner. The bank traders were more prone than psychopathic patients to rely on strategies that considerably harmed the profit of their gaming partners without necessarily optimizing their own total profit. The community controls achieved the same overall gain as traders and psychopaths. Unlike traders and psychopathic patients, the normal controls balanced overall gains of themselves and their game opponent, which led to the highest overall profit, whereas the traders achieved the lowest overall profit

    Climate driven trends in tree biomass increment show asynchronous dependence on tree-ring width and wood density variation

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    Tree growth is a key ecosystem function supporting climate change mitigation strategies. However climate change may induce feedbacks on radial growth and wood density, affecting the carbon sequestration capacity of forests. Using a mixed modeling technique long-term trends in radial growth, wood density and above-ground biomass, defined as the product of the annual basal area growth with the wood density, of common beech (Fagus sylvatica) and sessile oak (Quercus petraea) in the Belgian Ardennes, were determined and explained using climate drivers of change. This modeling strategy allowed us to determine if the same conclusions can be drawn when only BAI is considered, as is assumed in most carbon sequestration studies, when looking at long-term trends in carbon sequestration. The models indicate that above-ground biomass increment changes over time are more driven by changes in radial growth than by changes in wood density. Nevertheless, the assumption of constant wood density in most carbon sequestration studies is incorrect. Ignoring wood density results in an underestimation of long-term trends in above-ground biomass increment for beech, and an overestimation of above-ground biomass increment for oak. Interesting is that radial growth is mostly driven by climate variables of the current year, whereas wood density is more driven by the climate variables of the previous year. Beech radial growth and wood density is found to be negatively influenced by drought and positively by water availability. Oak radial growth and wood density is negatively affected by late frost and positively by water availability. The findings of this study suggest that radial growth in combination with wood density should be used in carbon sequestration studies as different climate driven long-term trends in radial growth and wood density are found

    Review of the current status of RAS mutation testing in patients with metastatic colorectal cancer (mCRC): Flash-RAS study

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    Présentation PosterInternational audienceOBJECTIVES: In 2013, it was shown that mutations in KRAS exons 3 and 4, or NRAS exons 2 to 4 had a similar effect. The primary objective was to assess the practices in conducting RAS testing in 2014. The secondary objectives were to describe the evolution of the RAS testing prescription rates from 2011, the process and time required to obtain the results, and to analyze their impact on the therapeutic strategy. METHODS: FLASH-RAS is an observational retrospective French multicenter study. RESULTS: 375 mCRC patients diagnosed and initiating a 1st line treatment (L1) between March and June 2014 were analyzed. For 90.1% of the patients (IC95%= [87.1%; 93.2%]), a genotyping request for RAS biomarkers was made in L1, i.e. a significantly increased rate compared to 2011 (81.1% in 2011, p<0.001). For 75% of the patients, the request was made before or at least one month after the diagnosis of the first metastases (1st M). No increase was observed in the median and mean times to obtain the test results between 2011 and 2014 despite the increased number of exons tested. CONCLUSIONS: In 2014, the rate of RAS genotyping requests has been increasing since 2011. For a majority of patients, the request is made before or at the latest one month after 1st M diagnosis. Nevertheless, for 24.5% of the patients, the request is made more than one month after 1st M diagnosis, which is not compatible with an informed treatment decision in L1

    Insecticidal gel bait for the decimation of Ctenolepisma longicaudatum (Zygentoma: Lepismatidae) populations in libraries, museums, and archives

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    The problem of bristletail Ctenolepisma longicaudatum (Zygentoma: Lepismatidae) in libraries, archives, and museums is increasing. It can cause damage to valuable and irreplaceable objects. We describe the effect of the use of insecticidal gel bait (active ingredient: indoxacarb) against C. longicaudatum populations in three libraries, seven archives, and seven museums in Norway and Austria. Pest activity was monitored with sticky traps to evaluate the effect of bait application. Significant declines in pest populations were observed at all locations when small bait droplets were applied either systematically throughout the buildings or strategically close to suspected aggregations. In addition, bait was successfully used to prevent infestation in a new museum building. The cost of treatment, measured by the amount of bait and work hours spent, was low, and bait application was conducted by either the professional pest control technicians or the local integrated pest management (IPM) manager. The use of insecticidal gel bait and its secondary effects is a cost-efficient alternative for population decimation; moreover, the method has a low probability of negative health issues for employees at the treated localities or damage to the objects. The application of bait is discussed in relation to its alignment with other IPM methods in libraries, archives, and museums
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