1,641 research outputs found

    'The drugs did for me what I couldn’t do for myself’: A qualitative exploration of the relationship between mental health and amphetamine-type stimulant (ATS) use

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    Substance use and mental ill health constitute a major public health burden, and a key global policy priority is to reduce illicit and other harmful substance use. Amphetamine-type stimulants (ATS) are the second most used class of illicit drugs and a range of mental health issues have been documented amongst users. This paper explores the relationship between mental health and ATS use, through a thematic analysis of qualitative interviews with n=18 current and former ATS users in England. The findings are presented by trajectory point of; (1) Initiation of ATS use; (2) continued and increased ATS use; and (3) decreased and remitted ATS use. This work helps to develop understanding around the complex and bidirectional relationship between ATS use and mental health. Many ATS users lead chaotic lives and engage in multiple risk behaviours; however, there is a need to better understand and conceptualise the dynamic interaction between different individual, social, environment and cultural factors that determine individuals’ mental health and substance use. There is no ‘one size fits all’ approach to prevention and treatment, and these findings highlight the need for more joined-up, tailored, and holistic approaches to intervention development

    Using conservation science to advance corporate biodiversity accountability

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    Biodiversity declines threaten the sustainability of global economies and societies. Acknowledging this, businesses are beginning to make commitments to account for and mitigate their influence on biodiversity, and report this in sustainability reports. The top 100 of the 2016 Fortune 500 Global companies' (the Fortune 100) sustainability reports were assessed to gauge the current state of corporate biodiversity accountability. Many companies acknowledged biodiversity, but corporate biodiversity accountability is in its infancy. Almost half (49) of the Fortune 100 mentioned biodiversity in reports, and 31 made clear biodiversity commitments, of which only 5 could be considered specific, measureable and time?bound. A variety of biodiversity?related activities were disclosed (e.g., managing impacts, restoring biodiversity, and investing in biodiversity), but only 9 companies provided quantitative indicators to verify the magnitude of their activities (e.g., area of habitat restored). No companies reported quantitative biodiversity outcomes, making it difficult to determine whether business actions were of sufficient magnitude to address impacts, and are achieving positive outcomes for nature. Conservation science can help advance approaches to corporate biodiversity accountability through developing science?based biodiversity commitments, meaningful indicators, and more targeted activities to address business impacts. With the “biodiversity policy super?year” of 2020 rapidly approaching, now is the time for conservation scientists to engage with and support businesses to play a critical role in setting the new agenda for a sustainable future for the planet, with biodiversity at its heart

    An Axial Time-of-flight Mass Spectrometer for Upper Atmospheric Measurements

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    As the “shoreline” of the Earth’s atmosphere, the mesosphere/lower thermosphere (MLT) region is home to many interesting and important phenomena, the most visible of which are the auroras. Geomagnetic storms, in addition to causing very intense auroral activity, also deposit large amounts of energy into the earth’s ionosphere. Recent analysis of data from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument aboard the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) satellite suggests that 5.3ÎŒm emission from vibrationally excited NO is the main method of energy dissipation from energy deposited by geomagnetic storms. Additionally, NO+ has been shown to be the major contributor to geomagnetic storm induced 4.3ÎŒm nighttime emission. In order to better physically understand these two large sources of geomagnetic storm energy dissipation, a sounding rocket mission, ROCKet-borne Storm Energetics of Auroral Dosing in the E-region (ROCK-STEADE) is being proposed. The ROCK-STEADE instrument suite consists of several photometers, an interferometer, an IR spectrometer, and two time-of-flight mass spectrometers (TOFMS). The TOFMS will measure the ion and neutral compositions in the atmosphere as the sounding rocket travels through the MLT. Due to the use of microchannel plate (MCP) detectors in TOFMS, one of the major challenges to making measurements in the MLT is the high ambient pressure. Other challenges and sources of error and background include stray UV photons, scattering of gas molecules from the interior surfaces of the instrument, dissociation of molecules in the bow shock caused by the supersonic rocket flight, and reactive recombination at the surfaces of the instrument. Methods of dealing with these challenges include: ‱ Recent advances in MCP technology allowing MCP operation into the mtorr range ‱ Cooling the front surface of the TOFMS using liquid He to eliminate the bow shock (thus making possible the direct sampling of the ambient atmosphere) ‱ Cryogenically cooling the interior of the instrument to eliminate scattering of gas from instrument walls and therefore also reducing the contribution of reactive recombination ‱ Rigorous error analysis to account for the background contribution of stray U

    Microscopic Surface Structure of Liquid Alkali Metals

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    We report an x-ray scattering study of the microscopic structure of the surface of a liquid alkali metal. The bulk liquid structure factor of the eutectic K67Na33 alloy is characteristic of an ideal mixture, and so shares the properties of an elemental liquid alkali metal. Analysis of off-specular diffuse scattering and specular x-ray reflectivity shows that the surface roughness of the K-Na alloy follows simple capillary wave behavior with a surface structure factor indicative of surface induced layering. Comparison of thelow-angle tail of the K67Na33 surface structure factor with the one measured for liquid Ga and In previously suggests that layering is less pronounced in alkali metals. Controlled exposure of the liquid to H2 and O2 gas does not affect the surface structure, indicating that oxide and hydride are not stable at the liquid surface under these experimental conditions.Comment: 12 pages, 3 figures, published in Phys. Rev.

    Improving our understanding of metal implant failures: Multiscale chemical imaging of exogenous metals in ex-vivo biological tissues

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    Biological exposures to micro- and nano-scale exogenous metal particles generated as a consequence of in-service degradation of orthopaedic prosthetics can result in severe adverse tissues reactions. However, individual reactions are highly variable and are not easily predicted, due to in part a lack of understanding of the speciation of the metal-stimuli which dictates cellular interactions and toxicity. Investigating the chemistry of implant derived metallic particles in biological tissue samples is complicated by small feature sizes, low concentrations and often a heterogeneous speciation and distribution. These challenges were addressed by developing a multi-scale two-dimensional X-ray absorption spectroscopic (XAS) mapping approach to discriminate sub-micron changes in particulate chemistry within ex-vivo tissues associated with failed CoCrMo total hip replacements (THRs). As a result, in the context of THRs, we demonstrate much greater variation in Cr chemistry within tissues compared with previous reports. Cr compounds including phosphate, hydroxide, oxide, metal and organic complexes were observed and correlated with Co and Mo distributions. This variability may help explain the lack of agreement between biological responses observed in experimental exposure models and clinical outcomes. The multi-scale 2D XAS mapping approach presents an essential tool in discriminating the chemistry in dilute biological systems where speciation heterogeneity is expected. Significance: Metal implants are routinely used in healthcare but may fail following degradation in the body. Although specific implants can be identified as ‘high-risk’, our analysis of failures is limited by a lack of understanding of the chemistry of implant metals within the peri-prosthetic milieu. A new approach to identify the speciation and variability in speciation at sub-micron resolution, of dilute exogenous metals within biological tissues is reported; applied to understanding the failure of metallic (CoCrMo) total-hip-replacements widely used in orthopedic surgery. Much greater variation in Cr chemistry was observed compared with previous reports and included phosphate, hydroxide, oxide, metal and organic complexes. This variability may explain lack of agreement between biological responses observed in experimental exposure models and clinical outcomes

    Microscopic dynamics in liquid metals: the experimental point of view

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    The experimental results relevant for the understanding of the microscopic dynamics in liquid metals are reviewed, with special regards to the ones achieved in the last two decades. Inelastic Neutron Scattering played a major role since the development of neutron facilities in the sixties. The last ten years, however, saw the development of third generation radiation sources, which opened the possibility of performing Inelastic Scattering with X rays, thus disclosing previously unaccessible energy-momentum regions. The purely coherent response of X rays, moreover, combined with the mixed coherent/incoherent response typical of neutron scattering, provides enormous potentialities to disentangle aspects related to the collectivity of motion from the single particle dynamics. If the last twenty years saw major experimental developments, on the theoretical side fresh ideas came up to the side of the most traditional and established theories. Beside the raw experimental results, therefore, we review models and theoretical approaches for the description of microscopic dynamics over different length-scales, from the hydrodynamic region down to the single particle regime, walking the perilous and sometimes uncharted path of the generalized hydrodynamics extension. Approaches peculiar of conductive systems, based on the ionic plasma theory, are also considered, as well as kinetic and mode coupling theory applied to hard sphere systems, which turn out to mimic with remarkable detail the atomic dynamics of liquid metals. Finally, cutting edges issues and open problems, such as the ultimate origin of the anomalous acoustic dispersion or the relevance of transport properties of a conductive systems in ruling the ionic dynamic structure factor are discussed.Comment: 53 pages, 41 figures, to appear in "The Review of Modern Physics". Tentatively scheduled for July issu

    The Feasibility, Tolerability, Safety, and Accuracy of Low-radiation Dynamic Computed Tomography Myocardial Perfusion Imaging With Regadenoson Compared With Single-photon Emission Computed Tomography

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    Objectives: Computed tomography (CT) myocardial perfusion imaging (CT-MPI) with hyperemia induced by regadenoson was evaluated for the detection of myocardial ischemia, safety, relative radiation exposure, and patient experience compared with single-photon emission computed tomography (SPECT) imaging. Materials and Methods: Twenty-four patients (66.5 y, 29% male) who had undergone clinically indicated SPECT imaging and provided written informed consent were included in this phase II, IRB-approved, and FDA-approved clinical trial. All patients underwent coronary CT angiography and CT-MPI with hyperemia induced by the intravenous administration of regadenoson (0.4 mg/5 mL). Patient experience and findings on CT-MPI images were compared to SPECT imaging. Results: Patient experience and safety were similar between CT-MPI and SPECT procedures and no serious adverse events due to the administration of regadenoson occurred. SPECT resulted in a higher number of mild adverse events than CT-MPI. Patient radiation exposure was similar during the combined coronary computed tomography angiography and CT-MPI (4.4 [2.7] mSv) and SPECT imaging (5.6 [1.7] mSv) (P-value 0.401) procedures. Using SPECT as the reference standard, CT-MPI analysis showed a sensitivity of 58.3% (95% confidence interval [CI]: 27.7-84.8), a specificity of 100% (95% CI: 73.5-100), and an accuracy of 79.1% (95% CI: 57.9-92.87). Low apparent sensitivity occurred when the SPECT defects were small and highly suspicious for artifacts. Conclusions: This study demonstrated that CT-MPI is safe, well tolerated, and can be performed with comparable radiation exposure to SPECT. CT-MPI has the benefit of providing both complete anatomic coronary evaluation and assessment of myocardial perfusion

    A measurement of secondary cosmic microwave background anisotropies with two years of South Pole Telescope observations

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    We present the first three-frequency South Pole Telescope (SPT) cosmic microwave background (CMB) power spectra. The band powers presented here cover angular scales 2000 < ell < 9400 in frequency bands centered at 95, 150, and 220 GHz. At these frequencies and angular scales, a combination of the primary CMB anisotropy, thermal and kinetic Sunyaev-Zel'dovich (SZ) effects, radio galaxies, and cosmic infrared background (CIB) contributes to the signal. We combine Planck and SPT data at 220 GHz to constrain the amplitude and shape of the CIB power spectrum and find strong evidence for non-linear clustering. We explore the SZ results using a variety of cosmological models for the CMB and CIB anisotropies and find them to be robust with one exception: allowing for spatial correlations between the thermal SZ effect and CIB significantly degrades the SZ constraints. Neglecting this potential correlation, we find the thermal SZ power at 150 GHz and ell = 3000 to be 3.65 +/- 0.69 muK^2, and set an upper limit on the kinetic SZ power to be less than 2.8 muK^2 at 95% confidence. When a correlation between the thermal SZ and CIB is allowed, we constrain a linear combination of thermal and kinetic SZ power: D_{3000}^{tSZ} + 0.5 D_{3000}^{kSZ} = 4.60 +/- 0.63 muK^2, consistent with earlier measurements. We use the measured thermal SZ power and an analytic, thermal SZ model calibrated with simulations to determine sigma8 = 0.807 +/- 0.016. Modeling uncertainties involving the astrophysics of the intracluster medium rather than the statistical uncertainty in the measured band powers are the dominant source of uncertainty on sigma8 . We also place an upper limit on the kinetic SZ power produced by patchy reionization; a companion paper uses these limits to constrain the reionization history of the Universe.Comment: 25 pages; 14 figures; Submitted to ApJ (Updated to reflect referee comments

    The Surgical Infection Society revised guidelines on the management of intra-abdominal infection

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    Background: Previous evidence-based guidelines on the management of intra-abdominal infection (IAI) were published by the Surgical Infection Society (SIS) in 1992, 2002, and 2010. At the time the most recent guideline was released, the plan was to update the guideline every five years to ensure the timeliness and appropriateness of the recommendations. Methods: Based on the previous guidelines, the task force outlined a number of topics related to the treatment of patients with IAI and then developed key questions on these various topics. All questions were approached using general and specific literature searches, focusing on articles and other information published since 2008. These publications and additional materials published before 2008 were reviewed by the task force as a whole or by individual subgroups as to relevance to individual questions. Recommendations were developed by a process of iterative consensus, with all task force members voting to accept or reject each recommendation. Grading was based on the GRADE (Grades of Recommendation Assessment, Development, and Evaluation) system; the quality of the evidence was graded as high, moderate, or weak, and the strength of the recommendation was graded as strong or weak. Review of the document was performed by members of the SIS who were not on the task force. After responses were made to all critiques, the document was approved as an official guideline of the SIS by the Executive Council. Results: This guideline summarizes the current recommendations developed by the task force on the treatment of patients who have IAI. Evidence-based recommendations have been made regarding risk assessment in individual patients; source control; the timing, selection, and duration of antimicrobial therapy; and suggested approaches to patients who fail initial therapy. Additional recommendations related to the treatment of pediatric patients with IAI have been included. Summary: The current recommendations of the SIS regarding the treatment of patients with IAI are provided in this guideline
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