984 research outputs found

    Glory Oscillations in the Index of Refraction for Matter-Waves

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    We have measured the index of refraction for sodium de Broglie waves in gases of Ar, Kr, Xe, and nitrogen over a wide range of sodium velocities. We observe glory oscillations -- a velocity-dependent oscillation in the forward scattering amplitude. An atom interferometer was used to observe glory oscillations in the phase shift caused by the collision, which are larger than glory oscillations observed in the cross section. The glory oscillations depend sensitively on the shape of the interatomic potential, allowing us to discriminate among various predictions for these potentials, none of which completely agrees with our measurements

    Concept of Operations Evaluation for Mitigating Space Flight-Relevant Medical Issues in a Planetary Habitat

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    Introduction: Analogue environments assist the NASA Human Research Program (HRP) in developing capabilities to mitigate high risk issues to crew health and performance for space exploration. The Habitat Demonstration Unit (HDU) is an analogue habitat used to assess space-related products for planetary missions. The Exploration Medical Capability (ExMC) element at the NASA Johnson Space Center (JSC) was tasked with developing planetary-relevant medical scenarios to evaluate the concept of operations for mitigating medical issues in such an environment. Methods: Two medical scenarios were conducted within the simulated planetary habitat with the crew executing two space flight-relevant procedures: Eye Examination with a corneal injury and Skin Laceration. Remote guidance for the crew was provided by a flight surgeon (FS) stationed at a console outside of the habitat. Audio and video data were collected to capture the communication between the crew and the FS, as well as the movements of the crew executing the procedures. Questionnaire data regarding procedure content and remote guidance performance also were collected from the crew immediately after the sessions. Results: Preliminary review of the audio, video, and questionnaire data from the two scenarios conducted within the HDU indicate that remote guidance techniques from an FS on console can help crew members within a planetary habitat mitigate planetary-relevant medical issues. The content and format of the procedures were considered concise and intuitive, respectively. Discussion: Overall, the preliminary data from the evaluation suggest that use of remote guidance techniques by a FS can help HDU crew execute space exploration-relevant medical procedures within a habitat relevant to planetary missions, however further evaluations will be needed to implement this strategy into the complete concept of operations for conducting general space medicine within similar environment

    Detections of whale vocalizations by simultaneously deployed bottom-moored and deep-water mobile autonomous hydrophones

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    Funding for this work was provided by the Living Marine Resources Program (N39430-14-C-1435 and N39430-14-C-1434), the Office of Naval Research (N00014-15-1-2142, N00014-10-1-0534, and N00014-13-1-0682), and NOAA’s Southwest Fisheries Science Center. SF was supported by the National Science and Engineering Graduate Fellowship.Advances in mobile autonomous platforms for oceanographic sensing, including gliders and deep-water profiling floats, have provided new opportunities for passive acoustic monitoring (PAM) of cetaceans. However, there are few direct comparisons of these mobile autonomous systems to more traditional methods, such as stationary bottom moored recorders. Cross-platform comparisons are necessary to enable interpretation of results across historical and contemporary surveys that use different recorder types, and to identify potential biases introduced by the platform. Understanding tradeoffs across recording platforms informs best practices for future cetacean monitoring efforts. This study directly compares the PAM capabilities of a glider (Seaglider) and a deep-water profiling float (QUEphone) to a stationary seafloor system (High-frequency Acoustic Recording Package, or HARP) deployed simultaneously over a 2 week period in the Catalina Basin, California, United States. Two HARPs were deployed 4 km apart while a glider and deep-water float surveyed within 20 km of the HARPs. Acoustic recordings were analyzed for the presence of multiple cetacean species, including beaked whales, delphinids, and minke whales. Variation in acoustic occurrence at 1-min (beaked whales only), hourly, and daily scales were examined. The number of minutes, hours, and days with beaked whale echolocation clicks were variable across recorders, likely due to differences in the noise floor of each recording system, the spatial distribution of the recorders, and the short detection radius of such a high-frequency, directional signal type. Delphinid whistles and clicks were prevalent across all recorders, and at levels that may have masked beaked whale vocalizations. The number and timing of hours and days with minke whale boing sounds were nearly identical across recorder types, as was expected given the relatively long propagation distance of boings. This comparison provides evidence that gliders and deep-water floats record cetaceans at similar detection rates to traditional stationary recorders at a single point. The spatiotemporal scale over which these single hydrophone systems record sounds is highly dependent on acoustic features of the sound source. Additionally, these mobile platforms provide improved spatial coverage which may be critical for species that produce calls that propagate only over short distances such as beaked whales.Publisher PDFPeer reviewe

    Emergency Medicine Research Directors and Research Programs: Characteristics and Factors Associated with Productivity

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    : Background: Periodic surveys of research directors (RDs) in emergency medicine (EM) are useful to assess the specialty's development and evolution of the RD role. Objectives: To assess associations between characteristics and research productivity of RDs and EM programs. Methods: A survey of EM RDs was developed using the nominal group technique and pilot tested. RDs or surrogate respondents at programs certified by the Accreditation Council for Graduate Medical Education were contacted by e-mail in early 2005. The survey assessed programs' research infrastructure and productivity, as well as RD characteristics, responsibilities, and career satisfaction. Three measures of research productivity were empirically defined: research publications, grant awards, and grant revenue. Results: Responses were received from 86% of 123 EM programs. Productivity was associated with the presence of nonclinical faculty, dedicated research coordinators, and reduced clinical hours for research faculty. Programs with an RD did not have greater research productivity, using any measure, than those without an RD. The majority of RDs cited pursuing their own studies, obtaining funding, research mentoring, and research administration to be major responsibilities. The majority characterized internal research funding, grant development support, and support from other faculty as inadequate. Most RDs are satisfied with their careers and expect to remain in the position for three or more years. Conclusions: Research productivity of EM residency programs is associated with the presence of dedicated research faculty and staff and with reduced clinical demands for research faculty. Despite perceiving deficiencies in important resources, most RDs are professionally satisfied.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72908/1/j.aem.2006.01.027.pd

    The implementation research institute: Training mental health implementation researchers in the United States

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    Abstract Background The Implementation Research Institute (IRI) provides two years of training in mental health implementation science for 10 new fellows each year. The IRI is supported by a National Institute of Mental Health (NIMH) R25 grant and the Department of Veterans Affairs (VA). Fellows attend two annual week-long trainings at Washington University in St. Louis. Training is provided through a rigorous curriculum, local and national mentoring, a ‘learning site visit’ to a federally funded implementation research project, pilot research, and grant writing. Methods This paper describes the rationale, components, outcomes to date, and participant experiences with IRI. Results IRI outcomes include 31 newly trained implementation researchers, their new grant proposals, contributions to other national dissemination and implementation research training, and publications in implementation science authored by the Core Faculty and fellows. Former fellows have obtained independent research funding in implementation science and are beginning to serve as mentors for more junior investigators. Conclusions Based on the number of implementation research grant proposals and papers produced by fellows to date, the IRI is proving successful in preparing new researchers who can inform the process of making evidence-based mental healthcare more available through real-world settings of care and who are advancing the field of implementation science

    The role of sand lances (Ammodytes sp.) in the Northwest Atlantic ecosystem: a synthesis of current knowledge with implications for conservation and management

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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 Staudinger, M. D., Goyert, H., Suca, J. J., Coleman, K., Welch, L., Llopiz, J. K., Wiley, D., Altman, I., Applegate, A., Auster, P., Baumann, H., Beaty, J., Boelke, D., Kaufman, L., Loring, P., Moxley, J., Paton, S., Powers, K., Richardson, D., Robbins, J., Runge, J., Smith, B., Spiegel, C., & Steinmetz, H. The role of sand lances (Ammodytes sp.) in the Northwest Atlantic ecosystem: a synthesis of current knowledge with implications for conservation and management. Fish and Fisheries, 00, (2020): 1-34, doi:10.1111/faf.12445.The American sand lance (Ammodytes americanus, Ammodytidae) and the Northern sand lance (A. dubius, Ammodytidae) are small forage fishes that play an important functional role in the Northwest Atlantic Ocean (NWA). The NWA is a highly dynamic ecosystem currently facing increased risks from climate change, fishing and energy development. We need a better understanding of the biology, population dynamics and ecosystem role of Ammodytes to inform relevant management, climate adaptation and conservation efforts. To meet this need, we synthesized available data on the (a) life history, behaviour and distribution; (b) trophic ecology; (c) threats and vulnerabilities; and (d) ecosystem services role of Ammodytes in the NWA. Overall, 72 regional predators including 45 species of fishes, two squids, 16 seabirds and nine marine mammals were found to consume Ammodytes. Priority research needs identified during this effort include basic information on the patterns and drivers in abundance and distribution of Ammodytes, improved assessments of reproductive biology schedules and investigations of regional sensitivity and resilience to climate change, fishing and habitat disturbance. Food web studies are also needed to evaluate trophic linkages and to assess the consequences of inconsistent zooplankton prey and predator fields on energy flow within the NWA ecosystem. Synthesis results represent the first comprehensive assessment of Ammodytes in the NWA and are intended to inform new research and support regional ecosystem‐based management approaches.This manuscript is the result of follow‐up work stemming from a working group formed at a two‐day multidisciplinary and international workshop held at the Parker River National Wildlife Refuge, Massachusetts in May 2017, which convened 55 experts scientists, natural resource managers and conservation practitioners from 15 state, federal, academic and non‐governmental organizations with interest and expertise in Ammodytes ecology. Support for this effort was provided by USFWS, NOAA Stellwagen Bank National Marine Sanctuary, U.S. Department of the Interior, U.S. Geological Survey, Northeast Climate Adaptation Science Center (Award # G16AC00237), an NSF Graduate Research Fellowship to J.J.S., a CINAR Fellow Award to J.K.L. under Cooperative Agreement NA14OAR4320158, NSF award OCE‐1325451 to J.K.L., NSF award OCE‐1459087 to J.A.R, a Regional Sea Grant award to H.B. (RNE16‐CTHCE‐l), a National Marine Sanctuary Foundation award to P.J.A. (18‐08‐B‐196) and grants from the Mudge Foundation. The contents of this paper are the responsibility of the authors and do not necessarily represent the views of the National Oceanographic and Atmospheric Administration, U.S. Fish and Wildlife Service, New England Fishery Management Council and Mid‐Atlantic Fishery Management Council. This manuscript is submitted for publication with the understanding that the United States Government is authorized to reproduce and distribute reprints for Governmental purposes. Any use of trade, firm or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government

    Screening for Incidental Sars-Cov-2 Infection in a Neurocritical Care Unit: A Longitudinal Diagnostic Prediction Model

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    Background: Rapid diagnosis of SARS-CoV-2 infection in patients not primarily assigned with the diagnosis of COVID-19 is highly relevant to effectively rule out virus transmission among patients and medical staff. The purpose is to develop a model for the prediction of the actual presence of a SARS-CoV-2 infection before a valid test result is available and to avoid unnecessary testing in Critical Care Units. Methods: Datasets of laboratory and blood gas analysis tests were collected retrospectively for the development and subsequent validation of machine learning (ML) based models. The data set was composed of 1. 254 SARS-CoV-2 positive cases, collected in an ICU dedicated to patients with COVID-19 pneumonia, 2a. 914 SARS-CoV-2 negative patients treated in a Neurocritical Care Unit and 2b. 32 patients treated for severe influenza pneumonia in a Medical ICU at the same hospital. The models were subsequently validated on a dataset collected from the Neurocritical Care Unit that consisted of data from 7 positive and 42 negative patients. Models were adapted to newly available laboratory values throughout their ICU stay. Extremely Randomized Trees (ERT) and Random Forest (RF) models were evaluated. A baseline model comprising fully grown trees, an optimized model including optimal values for the maximum depth, and a simplified model that only uses the 6 most important features were trained. Results: The overall best model, evaluated via crossvalidation on the development set, is an optimized ERT model with a ROC AUC value of 0.946. The model performance on the validation set is best for the simplified RF model achieving a ROC AUC value of 0.701. Gini feature and permutation importance for the simplified RF model revealed hemoglobin, procalcitonin, C-reactive protein, glomerular filtration rate based on CKD-EPI equation, creatinine, and urea as the most important input features. Using the simplified RF model and a threshold of 0.012 for the probability, a sensitivity above 80% with a specificity of 43% is achieved. Compared to a hypothetical daily testing regimen, using a threshold of 0.145, the simplified RF model detects all positive cases, and, with a false positive rate of 35%, daily tests might be reduced by two thirds. Conclusions: The model developed may support the medical staff in the ICUs by enabling faster and more reliable recognition of COVID-19. Unnecessary serial test sampling might be reduced. To ensure the quality of the model before clinical use, it should be further validated in prospective patient cohorts

    High collocation of sand lance and protected top predators: implications for conservation and management

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    © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Silva, T. L., Wiley, D. N., Thompson, M. A., Hong, P., Kaufman, L., Suca, J. A., Llopiz, J. K., Baumann, H., & Fay, G. High collocation of sand lance and protected top predators: implications for conservation and management. Conservation Science and Practice, (2021): 3:e274, doi: 10.1111/csp2.274.Spatial relationships between predators and prey provide critical information for understanding and predicting climate‐induced shifts in ecosystem dynamics and mitigating human impacts. We used Stellwagen Bank National Marine Sanctuary as a case study to investigate spatial overlap among sand lance (Ammodytes dubius), a key forage fish species, and two protected predators: humpback whales (Megaptera novaeangliae) and great shearwaters (Ardenna gravis). We conducted 6 years (2013–2018) of standardized surveys and quantified spatial overlap using the global index of collocation. Results showed strong, consistent collocation among species across seasons and years, suggesting that humpback whales and great shearwater distributions are tightly linked to sand lance. We propose that identifying sand lance habitats may indicate areas where humpbacks and shearwaters aggregate and are particularly vulnerable to human activities. Understanding how sand lance influence predator distributions can inform species protection and sanctuary management under present and future scenarios.This work was supported by the Bureau of Ocean Energy Management [IA agreement M17PG0019], NOAA Stellwagen Bank National Marine Sanctuary, U.S. Geological Survey, the Volgenau Foundation, and the Mudge Foundation

    Bounds on SCFTs from Conformal Perturbation Theory

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    The operator product expansion (OPE) in 4d (super)conformal field theory is of broad interest, for both formal and phenomenological applications. In this paper, we use conformal perturbation theory to study the OPE of nearly-free fields coupled to SCFTs. Under fairly general assumptions, we show that the OPE of a chiral operator of dimension Δ=1+ϵ\Delta = 1+\epsilon with its complex conjugate always contains an operator of dimension less than 2Δ2 \Delta. Our bounds apply to Banks-Zaks fixed points and their generalizations, as we illustrate using several examples.Comment: 36 pages; v2: typos fixed, minor change

    Evolution of fNL to the adiabatic limit

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    We study inflationary perturbations in multiple-field models, for which zeta typically evolves until all isocurvature modes decay--the "adiabatic limit". We use numerical methods to explore the sensitivity of the nonlinear parameter fNL to the process by which this limit is achieved, finding an appreciable dependence on model-specific data such as the time at which slow-roll breaks down or the timescale of reheating. In models with a sum-separable potential where the isocurvature modes decay before the end of the slow-roll phase we give an analytic criterion for the asymptotic value of fNL to be large. Other examples can be constructed using a waterfall field to terminate inflation while fNL is transiently large, caused by descent from a ridge or convergence into a valley. We show that these two types of evolution are distinguished by the sign of the bispectrum, and give approximate expressions for the peak fNL.Comment: v1: 25 pages, plus Appendix and bibliography, 6 figures. v2: minor edits to match published version in JCA
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