3,386 research outputs found

    BLUE WATER AND WHITE POWDER: TRENDS IN MARITIME NARCOTICS TRAFFICKING IN THE GREATER CARIBBEAN

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    This thesis argues that drug traffickers and law enforcement are caught in a cycle of competitive adaptation and that traffickers have consistently adapted to law enforcement pressure. It uses a history of cocaine trafficking from 1970 to 2000 and a case study on “narco-submarines” to provide both a macro and micro view of the competition between law enforcement and drug traffickers in the Caribbean. This thesis finds that since its inception, cocaine interdiction has been largely ineffective despite the major increases in law enforcement resources from the 1970s to the 1990s, including the use of the U.S. military to support counternarcotics operations. Interdiction has been ineffective because traffickers can rapidly adapt to law enforcement pressure by changing their smuggling methods and shifting their routes.Captain, United States Marine CorpsApproved for public release. Distribution is unlimited

    Marines Need a Few Good Mules

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    Capt. Walker Mills is a student in the Naval Postgraduate School's Center for Homeland Defense and Security (CHDS) program.The article of record as published may be found at https://www.usni.org/magazines/proceedings/2022/april/marines-need-few-good-mule

    Seeding the Galactic Centre gas stream: gravitational instabilities set the initial conditions for the formation of protocluster clouds

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    Star formation within the Central Molecular Zone (CMZ) may be intimately linked to the orbital dynamics of the gas. Recent models suggest that star formation within the dust ridge molecular clouds (from G0.253+0.016 to Sgr B2) follows an evolutionary time sequence, triggered by tidal compression during their preceding pericentre passage. Given that these clouds are the most likely precursors to a generation of massive stars and extreme star clusters, this scenario would have profound implications for constraining the time-evolution of star formation. In this Letter, we search for the initial conditions of the protocluster clouds, focusing on the kinematics of gas situated upstream from pericentre. We observe a highly-regular corrugated velocity field in {l,vLSR}\{l,\,v_{\rm LSR}\} space, with amplitude and wavelength A=3.7±0.1A=3.7\,\pm\,0.1 kms1^{-1} and λvel,i=22.5±0.1\lambda_{\rm vel, i}=22.5\,\pm\,0.1 pc, respectively. The extremes in velocity correlate with a series of massive (104\sim10^{4}M_{\odot}) and compact (Req2R_{\rm eq}\sim2 pc), quasi-regularly spaced (8\sim8 pc), molecular clouds. The corrugation wavelength and cloud separation closely agree with the predicted Toomre (17\sim17 pc) and Jeans (6\sim6 pc) lengths, respectively. We conclude that gravitational instabilities are driving the condensation of molecular clouds within the Galactic Centre gas stream. Furthermore, we speculate these seeds are the historical analogue of the dust-ridge molecular clouds, representing the initial conditions of star and cluster formation in the CMZ

    High-sensitivity troponin I concentrations are a marker of an advanced hypertrophic response and adverse outcomes in patients with aortic stenosis

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    Aims: High-sensitivity cardiac troponin I (cTnI) assays hold promise in detecting the transition from hypertrophy to heart failure in aortic stenosis. We sought to investigate the mechanism for troponin release in patients with aortic stenosis and whether plasma cTnI concentrations are associated with long-term outcome. Methods and results: Plasma cTnI concentrations were measured in two patient cohorts using a high-sensitivity assay. First, in the Mechanism Cohort, 122 patients with aortic stenosis (median age 71, 67% male, aortic valve area 1.0 ± 0.4 cm2) underwent cardiovascular magnetic resonance and echocardiography to assess left ventricular (LV) myocardial mass, function, and fibrosis. The indexed LV mass and measures of replacement fibrosis (late gadolinium enhancement) were associated with cTnI concentrations independent of age, sex, coronary artery disease, aortic stenosis severity, and diastolic function. In the separate Outcome Cohort, 131 patients originally recruited into the Scottish Aortic Stenosis and Lipid Lowering Trial, Impact of REgression (SALTIRE) study, had long-term follow-up for the occurrence of aortic valve replacement (AVR) and cardiovascular deaths. Over a median follow-up of 10.6 years (1178 patient-years), 24 patients died from a cardiovascular cause and 60 patients had an AVR. Plasma cTnI concentrations were associated with AVR or cardiovascular death HR 1.77 (95% CI, 1.22 to 2.55) independent of age, sex, systolic ejection fraction, and aortic stenosis severity. Conclusions: In patients with aortic stenosis, plasma cTnI concentration is associated with advanced hypertrophy and replacement myocardial fibrosis as well as AVR or cardiovascular death

    'The Brick' is not a brick : A comprehensive study of the structure and dynamics of the Central Molecular Zone cloud G0.253+0.016

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    © 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.In this paper we provide a comprehensive description of the internal dynamics of G0.253+0.016 (a.k.a. 'the Brick'); one of the most massive and dense molecular clouds in the Galaxy to lack signatures of widespread star formation. As a potential host to a future generation of high-mass stars, understanding largely quiescent molecular clouds like G0.253+0.016 is of critical importance. In this paper, we reanalyse Atacama Large Millimeter Array cycle 0 HNCO J=4(0,4)3(0,3)J=4(0,4)-3(0,3) data at 3 mm, using two new pieces of software which we make available to the community. First, scousepy, a Python implementation of the spectral line fitting algorithm scouse. Secondly, acorns (Agglomerative Clustering for ORganising Nested Structures), a hierarchical n-dimensional clustering algorithm designed for use with discrete spectroscopic data. Together, these tools provide an unbiased measurement of the line of sight velocity dispersion in this cloud, σvlos,1D=4.4±2.1\sigma_{v_{los}, {\rm 1D}}=4.4\pm2.1 kms1^{-1}, which is somewhat larger than predicted by velocity dispersion-size relations for the Central Molecular Zone (CMZ). The dispersion of centroid velocities in the plane of the sky are comparable, yielding σvlos,1D/σvpos,1D1.2±0.3\sigma_{v_{los}, {\rm 1D}}/\sigma_{v_{pos}, {\rm 1D}}\sim1.2\pm0.3. This isotropy may indicate that the line-of-sight extent of the cloud is approximately equivalent to that in the plane of the sky. Combining our kinematic decomposition with radiative transfer modelling we conclude that G0.253+0.016 is not a single, coherent, and centrally-condensed molecular cloud; 'the Brick' is not a \emph{brick}. Instead, G0.253+0.016 is a dynamically complex and hierarchically-structured molecular cloud whose morphology is consistent with the influence of the orbital dynamics and shear in the CMZ.Peer reviewedFinal Accepted Versio

    JWST reveals widespread CO ice and gas absorption in the Galactic Center cloud G0.253+0.016

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    We report JWST NIRCam observations of G0.253+0.016, the molecular cloud in the Central Molecular Zone known as The Brick, with the F182M, F187N, F212N, F410M, F405N, and F466N filters. We catalog 56,146 stars detected in all 6 filters using the crowdsource package. Stars within and behind The Brick exhibit prodigious absorption in the F466N filter that is produced by a combination of CO ice and gas. In support of this conclusion, and as a general resource, we present models of CO gas and ice and CO2_2 ice in the F466N, F470N, and F410M filters. Both CO gas and ice may contribute to the observed stellar colors. We show, however, that CO gas does not absorb the Pfβ\beta and Huϵ\epsilon lines in F466N, but that these lines show excess absorption, indicating that CO ice is also present and contributes to observed F466N absorption. The most strongly absorbed stars in F466N are extincted by \sim 2 magnitudes, corresponding to >> 80\% flux loss. This high observed absorption requires very high column densities of CO, requiring total CO column that is in tension with standard CO abundance and/or gas-to-dust ratios. There is therefore likely to be a greater CO/H2_2 ratio (XCO>104_{CO} > 10^{-4}) and more dust per H2_2 molecule (>0.01>0.01) in the Galactic Center than the Galactic disk. Ice and/or gas absorption is observed even in the cloud outskirts, implying that additional caution is needed when interpreting stellar photometry in filters that overlap with ice bands throughout our Galactic Center. The widespread CO absorption in our Galactic Center hints that significant ice absorption is likely present in other galactic centers.Comment: Submitted to ApJ. Revised after second referee report. 16 pages, 11 figure

    Problem gambling: a suitable case for social work?

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    Problem gambling attracts little attention from health and social care agencies in the UK. Prevalence surveys suggest that 0.6% of the population are problem gamblers and it is suggested that for each of these individuals, 10–17 other people, including children and other family members, are affected. Problem gambling is linked to many individual and social problems including: depression, suicide, significant debt, bankruptcy, family conflict, domestic violence, neglect and maltreatment of children and offending. This makes the issue central to social work territory. Yet, the training of social workers in the UK has consistently neglected issues of addictive behaviour. Whilst some attention has been paid in recent years to substance abuse issues, there has remained a silence in relation to gambling problems. Social workers provide more help for problems relating to addictions than other helping professions. There is good evidence that treatment, and early intervention for gambling problems, including psycho-social and public health approaches, can be very effective. This paper argues that problem gambling should be moved onto the radar of the social work profession, via inclusion on qualifying and post-qualifying training programmes and via research and dissemination of good practice via institutions such as the Social Care Institute for Excellence (SCIE). Keywords: problem gambling; addictive behaviour; socia

    Implications of lowering threshold of plasma troponin concentration in diagnosis of myocardial infarction: cohort study

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    Objective To assess the relation between troponin concentration, assay precision, and clinical outcomes in patients with suspected acute coronary syndrome

    Estimating detection and density of the Andean cat in the high Andes

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    The Andean cat (Leopardus jacobita) is one of the most endangered, yet least known, felids. Although the Andean cat is considered at risk of extinction, rigorous quantitative population studies are lacking. Because physical observations of the Andean cat are difficult to make in the wild, we used a camera-trapping array to photo-capture individuals. The survey was conducted in northwestern Argentina at an elevation of approximately 4,200 m during October-December 2006 and April-June 2007. In each year we deployed 22 pairs of camera traps, which were strategically placed. To estimate detection probability and density we applied models for spatial capture-recapture using a Bayesian framework. Estimated densities were 0.07 and 0.12 individual/km 2 for 2006 and 2007, respectively. Mean baseline detection probability was estimated at 0.07. By comparison, densities of the Pampas cat (Leopardus colocolo), another poorly known felid that shares its habitat with the Andean cat, were estimated at 0.74-0.79 individual/km2 in the same study area for 2006 and 2007, and its detection probability was estimated at 0.02. Despite having greater detectability, the Andean cat is rarer in the study region than the Pampas cat. Properly accounting for the detection probability is important in making reliable estimates of density, a key parameter in conservation and management decisions for any species. © 2011 American Society of Mammalogists.Fil: Reppucci, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Gardner, Beth. United States Geological Survey; Estados UnidosFil: Lucherini, Mauro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentin

    The dynamical evolution of molecular clouds near the Galactic Centre – II. Spatial structure and kinematics of simulated clouds

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    This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.The evolution of molecular clouds in galactic centres is thought to differ from that in galactic discs due to a significant influence of the external gravitational potential. We present a set of numerical simulations of molecular clouds orbiting on the 100-pc stream of the Central Molecular Zone (the central ∼500pc of the Galaxy) and characterize their morphological and kinematic evolution in response to the background potential and eccentric orbital motion. We find that the clouds are shaped by strong shear and torques, by tidal and geometric deformation, and by their passage through the orbital pericentre. Within our simulations, these mechanisms control cloud sizes, aspect ratios, position angles, filamentary structure, column densities, velocity dispersions, line-of-sight velocity gradients, spin angular momenta, and kinematic complexity. By comparing these predictions to observations of clouds on the Galactic Centre ‘dust ridge’, we find that our simulations naturally reproduce a broad range of key observed morphological and kinematic features, which can be explained in terms of well-understood physical mechanisms. We argue that the accretion of gas clouds on to the central regions of galaxies, where the rotation curve turns over and the tidal field is fully compressive, is accompanied by transformative dynamical changes to the clouds, leading to collapse and star formation. This can generate an evolutionary progression of cloud collapse with a common starting point, which either marks the time of accretion on to the tidally compressive region or of the most recent pericentre passage. Together, these processes may naturally produce the synchronized starbursts observed in numerous (extra)galactic nuclei
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