526 research outputs found
The Tinsley Diagram Revisited
Motivated by the recent determinations of the Hubble constant from
observations of Cepheid variables in NGC4571 and M100, we plot the Tinsley
diagram with level curves of the cosmological constant . Based on
current estimates of the absolute ages of globular clusters we conclude that
and, irrespective of the background spatial curvature, the
universe will not recollapse. These conclusions hold for both relativistic and
Newtonian models and are {\it independent} of the density parameter.Comment: 8 pages, uses aasms.sty, 1 uuencoded PostScript figure appended,
(accepted to appear in Ap.J.Letters
Force and acceleration characteristics of military foot drill: implications for injury risk in recruits
Background: Foot drill involving marching and drill manoeuvres is conducted regularly during basic military recruit training. Characterising the biomechanical loading of foot drill will improve our understanding of the contributory factors to lower limb overuse injuries in recruits.
Aim: Quantify and compare forces, loading rates and accelerations of British Army foot drill, within and between trained and untrained personnel.
Methods: 24 trained soldiers (12 men and 12 women; TRAINED) and 12 civilian men (UNTRAINED) performed marching and five drill manoeuvres on force platforms; motion capture recorded tibial position. Peak vertical impact force (PF), peak vertical loading rate (PLR), expressed as multiples of body weight (BW) and peak tibial impact acceleration (PTA) were recorded.
Results: Drill manoeuvre PF, PLR and PTA were similar, but higher in TRAINED men (PF, PLR: p<0.01; PTA: p<0.05). Peak values in TRAINED men were shown for the halt (mean (SD); PF: 6.5 (1.5) BW; PLR: 983 (333) BW/s PTA; PTA: 207 (57) m/s2) and left turn (PF: 6.6 (1.7) BW; PLR: 928 (300) BW/s; 184 (62) m/s2). Marching PF, PLR, PTA were similar between groups and lower than all drill manoeuvres (PF: 1.1â1.3 BW; PLR: 42â70 BW/s; p<0.01; PTA: 23â38 m/s2; p<0.05). Conclusions: Army foot drill generates higher forces, loading rates and accelerations than activities such as running and load carriage, while marching is comparable to moderate running (10.8 km/h). The large biomechanical loading of foot drill may contribute to the high rate of overuse injuries during initial military training, and strategies to regulate/reduce this loading should be explored
Local Evolutionary Debunking Arguments
Evolutionary debunking arguments in ethics aim to use facts about the evolutionary causes of ethical beliefs to undermine their justification. Global Evolutionary Debunking Arguments (GDAs) are arguments made in metaethics that aim to undermine the justification of all ethical beliefs. Local Evolutionary Debunking Arguments (LDAs) are arguments made in firstâorder normative ethics that aim to undermine the justification of only some of our ethical beliefs. Guy Kahane, Regina Rini, Folke Tersman, and Katia Vavova argue for skepticism about the possibility of LDAs. They argue that LDAs cannot be successful because they overâextend in a way that makes them selfâundermining and yield a form of moral skepticism. In this paper I argue that this skepticism about the possibility of LDAs is misplaced
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Using Microstructure Observations to Quantify Fracture Properties and Improve Reservoir Simulations
The research for this project, funded by the U.S. Department of Energy, provides new technology to understand and successfully characterize, predict, and simulate reservoir-scale fractures. Such fractures have worldwide importance because of their influence on successful extraction of resources. For example, many conventional U.S. reservoirs yield about one-third of the oil originally in place, but some estimates suggest that reservoirs with naturally occurring fractures yield only about 10 percent of their reserves. This is a serious technical and financial challenge for producers of reservoirs containing natural fractures.
Most fractures are below the limits of seismic resolution or detection and are difficult or impossible to characterize adequately using currently available well test, full-diameter core, or geophysical well log technology; this is because large fractures are intrinsically difficult to sample with conventional wellbore sampling methods owing to their wide spacing. Consequently, fractured reservoirs have been intractable to describe and interpret effectively, impeding accurate reservoir description and simulation. Accurate characterization of reservoir fractures, however, still holds great potential for improving production by increasing the efficiency of exploration and recovery processes.Bureau of Economic Geolog
Open Educational Resources in Kentucky
Open educational resources (OER) play an increasingly important role in the education landscape, with increased awareness and use year over year (Coffey). Often, academic libraries play a supporting role for instructors as they locate, adopt, and create OER for their courses. In this article, we will provide an introduction to OER, outline some current trends in open education, and describe a few of the OER initiatives currently underway in Kentuckyâs college and university libraries
Monitoring the US ATLAS Network Infrastructure with perfSONAR-PS
Global scientific collaborations, such as ATLAS, continue to push the network requirements envelope. Data movement in this collaboration is routinely including the regular exchange of petabytes of datasets between the collection and analysis facilities in the coming years. These requirements place a high emphasis on networks functioning at peak efficiency and availability; the lack thereof could mean critical delays in the overall scientific progress of distributed data-intensive experiments like ATLAS. Network operations staff routinely must deal with problems deep in the infrastructure; this may be as benign as replacing a failing piece of equipment, or as complex as dealing with a multi-domain path that is experiencing data loss. In either case, it is crucial that effective monitoring and performance analysis tools are available to ease the burden of management. We will report on our experiences deploying and using the perfSONAR-PS Performance Toolkit at ATLAS sites in the United States. This software creates a dedicated monitoring server, capable of collecting and performing a wide range of passive and active network measurements. Each independent instance is managed locally, but able to federate on a global scale; enabling a full view of the network infrastructure that spans domain boundaries. This information, available through web service interfaces, can easily be retrieved to create customized applications. The US ATLAS collaboration has developed a centralized ĂąâŹĆĄĂâĂÂșdashboardĂąâŹĆĄĂâĂÂč offering network administrators, users, and decision makers the ability to see the performance of the network at a glance. The dashboard framework includes the ability to notify users (alarm) when problems are found, thus allowing rapid response to potential problems and making perfSONAR-PS crucial to the operation of our distributed computing infrastructure.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98635/1/1742-6596_396_4_042038.pd
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COMT genetic variation confers risk for psychotic and affective disorders: a case control study
BACKGROUND: Variation in the COMT gene has been implicated in a number of psychiatric disorders, including psychotic, affective and anxiety disorders. The majority of these studies have focused on the functional Val108/158Met polymorphism and yielded conflicting results, with limited studies examining the relationship between other polymorphisms, or haplotypes, and psychiatric illness. We hypothesized that COMT variation may confer a general risk for psychiatric disorders and have genotyped four COMT variants (Val158Met, rs737865, rs165599, and a SNP in the P2 promoter [-278A/G; rs2097603]) in 394 Caucasian cases and 467 controls. Cases included patients with schizophrenia (n = 196), schizoaffective disorder (n = 62), bipolar disorder (n = 82), major depression (n = 30), and patients diagnosed with either psychotic disorder NOS or depressive disorder NOS (n = 24). RESULTS: SNP rs2097603, the Val/Met variant and SNP rs165599 were significantly associated (p = 0.004; p = 0.05; p = 0.035) with a broad "all affected" diagnosis. Haplotype analysis revealed a potentially protective G-A-A-A haplotype haplotype (-278A/G; rs737865; Val108/158Met; rs165599), which was significantly underrepresented in this group (p = 0.0033) and contained the opposite alleles of the risk haplotype previously described by Shifman et al. Analysis of diagnostic subgroups within the "all affecteds group" showed an association of COMT in patients with psychotic disorders as well as in cases with affective illness although the associated variants differed. The protective haplotype remained significantly underrepresented in most of these subgroups. CONCLUSION: Our results support the view that COMT variation provides a weak general predisposition to neuropsychiatric disease including psychotic and affective disorders
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Border Security: Inspections Practices, Policies, and Issues
Some argue that this reorganization of border inspections has been long needed and is resulting in a more streamlined and efficient set of procedures at the border with a clear, single, chain of command. Others warn that the different types of inspections are quite complex in their own right and that the reorganization is exacerbating the conflicting priorities at the border, ultimately resulting in many more people and goods being sent to secondary inspections. This report, which will not be updated, discusses a range of legal, administrative, and policy issues that are emerging with the implementation of the unified border inspections
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Weight gain among treatment-naĂŻve persons with HIV starting integrase inhibitors compared to non-nucleoside reverse transcriptase inhibitors or protease inhibitors in a large observational cohort in the United States and Canada.
IntroductionWeight gain following antiretroviral therapy (ART) initiation is common, potentially predisposing some persons with HIV (PWH) to cardio-metabolic disease. We assessed relationships between ART drug class and weight change among treatment-naĂŻve PWH initiating ART in the North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD).MethodsAdult, treatment-naĂŻve PWH in NA-ACCORD initiating integrase strand transfer inhibitor (INSTI), protease inhibitor (PI) or non-nucleoside reverse-transcriptase inhibitor (NNRTI)-based ART on/after 1 January 2007 were followed through 31 December 2016. Multivariate linear mixed effects models estimated weight up to five years after ART initiation, adjusting for age, sex, race, cohort site, HIV acquisition mode, treatment year, and baseline weight, plasma HIV-1 RNA level and CD4+ cell count. Due to shorter follow-up for PWH receiving newer INSTI drugs, weights for specific INSTIs were estimated at two years. Secondary analyses using logistic regression and all covariates from primary analyses assessed factors associated with >10% weight gain at two and five years.ResultsAmong 22,972 participants, 87% were male, and 41% were white. 49% started NNRTI-, 31% started PI- and 20% started INSTI-based regimens (1624 raltegravir (RAL), 2085 elvitegravir (EVG) and 929 dolutegravir (DTG)). PWH starting INSTI-based regimens had mean estimated five-year weight change of +5.9kg, compared to +3.7kg for NNRTI and +5.5kg for PI. Among PWH starting INSTI drugs, mean estimated two-year weight change was +7.2kg for DTG, +5.8kg for RAL and +4.1kg for EVG. Women, persons with lower baseline CD4+ cell counts, and those initiating INSTI-based regimens had higher odds of >10% body weight increase at two years (adjusted odds ratio = 1.37, 95% confidence interval: 1.20 to 1.56 vs. NNRTI).ConclusionsPWH initiating INSTI-based regimens gained, on average, more weight compared to NNRTI-based regimens. This phenomenon may reflect heterogeneous effects of ART agents on body weight regulation that require further exploration
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