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Search Results: 1 - 10 of 327971 matches for " Corey S Davis "
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Bundling occupational safety with harm reduction information as a feasible method for improving police receptiveness to syringe access programs: evidence from three U.S. cities
Corey S Davis, Leo Beletsky
Harm Reduction Journal , 2009, DOI: 10.1186/1477-7517-6-16
Abstract: We report on a brief training intervention for law enforcement personnel designed to increase officer knowledge of and positive attitudes towards SAPs by bundling content that addresses officer concerns about infectious disease and occupational safety with information about the legality and public health benefits of these programs. Pilot trainings using this bundled curriculum were conducted with approximately 600 officers in three US cities.Law enforcement officers were generally receptive to receiving information about SAPs through the bundled curriculum. The trainings led to better communication and collaboration between SAP and law enforcement personnel, providing a valuable platform for better harmonization of law enforcement and public health activities targeting injection drug users.The experience in these three cities suggests that a harm reduction training curriculum that bundles strategies for increasing officer occupational safety with information about the legality and public health benefits of SAPs can be well received by law enforcement personnel and can lead to better communication and collaboration between law enforcement and harm reduction actors. Further study is indicated to assess whether such a bundled curriculum is effective in changing officer attitudes and beliefs and reducing health risks to officers and injection drug users, as well as broader benefits to the community at large.The spread of bloodborne disease through injection drug use is a longstanding problem in the United States and abroad, with syringe sharing as the primary modality for disease transmission among injection drug users (IDUs) [1,2]. Many states and localities have implemented syringe access programs (SAPs) to reduce the sharing of syringes, including over the counter syringe sales and syringe exchange programs (SEPs) [3]. These interventions have been associated with decreased incidence of bloodborne disease and risky syringe-related behaviors among IDUs. They have also
Harmonizing disease prevention and police practice in the implementation of HIV prevention programs: Up-stream strategies from Wilmington, Delaware
Basha Silverman, Corey S Davis, Julia Graff, Umbreen Bhatti, Melissa Santos, Leo Beletsky
Harm Reduction Journal , 2012, DOI: 10.1186/1477-7517-9-17
Abstract: In 2006, the Delaware legislature authorized a pilot syringe exchange program (SEP). A program designed to prevent, monitor, and respond to possible policing and community barriers before they had a chance to effect program implementation and operation. A program designed to prevent, monitor, and respond to these barriers was planned and implemented by a multidisciplinary team of legal practitioners and public health professionals.We report on an integrated intervention to address structural barriers to syringe exchange program utilization. This intervention employs community, police and client education combined with systematic surveillance of and rapid response to police interference to preempt the kinds of structural barriers to implementation observed elsewhere. The intervention addresses community concerns and stresses the benefits of syringe exchange programs to officer occupational safety.A cohesive effort combining collaboration with and educational outreach to police and community members based on the needs and concerns of these groups as well as SEP clients and potential clients helped establish a supportive street environment for the SEP. Police-driven structural barriers to implementation of public health programs targeting populations engaged in drug use and other illicit behavior can be addressed by up-stream planning, prevention, monitoring and intervention strategies. More research is needed to inform the tailoring of interventions to address police-driven barriers to HIV prevention services, especially among marginalized populations.The spread of blood-borne disease through injection drug use is a longstanding problem, with a substantial proportion of HIV, hepatitis B, and hepatitis C (HCV) cases in the United States attributable to injection-related behaviors [1]. Evidence-based prevention interventions such as syringe exchange programs (SEPs) have been demonstrated to reduce risky injection-related behavior and injection-related transmission of bl
Chemical immobilization of adult female Weddell seals with tiletamine and zolazepam: effects of age, condition and stage of lactation
Kathryn E Wheatley, Corey JA Bradshaw, Robert G Harcourt, Lloyd S Davis, Mark A Hindell
BMC Veterinary Research , 2006, DOI: 10.1186/1746-6148-2-8
Abstract: The tiletamine:zolazepam mixture administered intravenously was an effective method for immobilization with no fatalities or pronounced apnoeas in 106 procedures; however, there was a 25 % (one animal in four) mortality rate with intramuscular administration. Induction time was slightly longer for females at the end of lactation (54.9 ± 2.3 seconds) than at post-parturition (48.2 ± 2.9 seconds). In addition, the number of previous captures had a positive effect on induction time. There was no evidence for effects due to age, condition (total body lipid), stage of lactation or number of captures on recovery time.We suggest that intravenous administration of tiletamine and zolazepam is an effective and safe immobilizing agent for female Weddell seals. Although individual traits could not explain variation in recovery time, we suggest careful monitoring of recovery times during longitudinal studies (> 2 captures). We show that physiological pressures do not substantially affect response to chemical immobilization with this mixture; however, consideration must be taken for differences that may exist for immobilization of adult males and juveniles. Nevertheless, we recommend a mass-specific dose of 0.50 – 0.65 mg/kg for future procedures with adult female Weddell seals and a starting dose of 0.50 mg/kg for other age classes and other phocid seals.Immobilization of captive and free-ranging pinnipeds is often required for biological studies, translocation or the examination of sick or injured animals. However, pinnipeds present unique problems when using chemical immobilization agents because they have evolved specific adaptations in their respiratory, cardiovascular and thermoregulatory systems enabling them to dive for extended periods. These adaptations can exacerbate problems associated with chemical immobilization procedures [1,2]. This physiological "dive response" is characterized by profound bradycardia, shunting of blood away from peripheral tissues, and periods o
Genetic linkage map of a wild genome: genomic structure, recombination and sexual dimorphism in bighorn sheep
Jocelyn Poissant, John T Hogg, Corey S Davis, Joshua M Miller, Jillian F Maddox, David W Coltman
BMC Genomics , 2010, DOI: 10.1186/1471-2164-11-524
Abstract: Bighorn sheep population-specific maps differed slightly in contiguity but were otherwise very similar in terms of genomic structure and recombination rates. The joint analysis of the two pedigrees resulted in a highly contiguous map composed of 247 microsatellite markers distributed along all 26 autosomes and the X chromosome. The map is estimated to cover about 84% of the bighorn sheep genome and contains 240 unique positions spanning a sex-averaged distance of 3051 cM with an average inter-marker distance of 14.3 cM. Marker synteny, order, sex-averaged interval lengths and sex-averaged total map lengths were all very similar between sheep species. However, in contrast to domestic sheep, but consistent with the usual pattern for a placental mammal, recombination rates in bighorn sheep were significantly greater in females than in males (~12% difference), resulting in an autosomal female map of 3166 cM and an autosomal male map of 2831 cM. Despite differing genome-wide patterns of heterochiasmy between the sheep species, sexual dimorphism in recombination rates was correlated between orthologous intervals.We have developed a first-generation bighorn sheep linkage map that will facilitate future studies of the genetic architecture of trait variation in this species. While domestication has been hypothesized to be responsible for the elevated mean recombination rate observed in domestic sheep, our results suggest that it is a characteristic of Ovis species. However, domestication may have played a role in altering patterns of heterochiasmy. Finally, we found that interval-specific patterns of sexual dimorphism were preserved among closely related Ovis species, possibly due to the conserved position of these intervals relative to the centromeres and telomeres. This study exemplifies how transferring genomic resources from domesticated species to close wild relative can benefit evolutionary ecologists while providing insights into the evolution of genomic structure and
Viscoplasticity and large-scale chain relaxation in glassy-polymeric strain hardening
Robert S. Hoy,Corey S. O'Hern
Physics , 2010, DOI: 10.1103/PhysRevE.82.041803
Abstract: A simple theory for glassy polymeric mechanical response which accounts for large scale chain relaxation is presented. It captures the crossover from perfect-plastic response to strong strain hardening as the degree of polymerization $N$ increases, without invoking entanglements. By relating hardening to interactions on the scale of monomers and chain segments, we correctly predict its magnitude. Strain activated relaxation arising from the need to maintain constant chain contour length reduces the $N$ dependence of the characteristic relaxation time by a factor $\sim \dot\epsilon N$ during active deformation at strain rate $\dot\epsilon$. This prediction is consistent with results from recent experiments and simulations, and we suggest how it may be further tested experimentally.
Minimal energy packings and collapse of sticky tangent hard-sphere polymers
Robert S. Hoy,Corey S. O'Hern
Physics , 2010, DOI: 10.1103/PhysRevLett.105.068001
Abstract: We enumerate all minimal energy packings (MEPs) for small single linear and ring polymers composed of spherical monomers with contact attractions and hard-core repulsions, and compare them to corresponding results for monomer packings. We define and identify ``dividing surfaces" in polymer packings, which reduce the number of arrangements that satisfy hard-sphere and covalent bond constraints. Compared to monomer MEPs, polymer MEPs favor intermediate structural symmetry over high and low symmetries. We also examine the packing-preparation dependence for longer single chains using molecular dynamics simulations. For slow temperature quenches, chains form crystallites with close-packed cores. As quench rate increases, the core size decreases and the exterior becomes more disordered. By examining the contact number, we connect suppression of crystallization to the onset of isostaticity in disordered packings. These studies represent a significant step forward in our ability to predict how the structural and mechanical properties of compact polymers depend on collapse dynamics.
Glassy dynamics of crystallite formation: The role of covalent bonds
Robert S. Hoy,Corey S. O'Hern
Physics , 2011,
Abstract: We examine nonequilibrium features of collapse behavior in model polymers with competing crystallization and glass transitions using extensive molecular dynamics simulations. By comparing to "colloidal" systems with no covalent bonds but the same non-bonded interactions, we find three principal results: (i) Tangent-sphere polymers and colloids, in the equilibrium-crystallite phase, have nearly identical static properties when the temperature T is scaled by the crystallization temperature T_{cryst}; (ii) Qualitative features of nonequilibrium relaxation below T_{cryst}, measured by the evolution of local structural properties (such as the number of contacts) toward equilibrium crystallites, are the same for polymers and colloids; and (iii) Significant quantitative differences in rearrangements in polymeric and colloidal crystallites, in both far-from equilibrium and near-equilibrium systems, can be understood in terms of chain connectivity. These results have important implications for understanding slow relaxation processes in collapsed polymers, partially folded, misfolded, and intrinsically disordered proteins.
Socioeconomic Position, Rural Residence, and Marginality Influences on Obesity Status in the Adult Mexican Population
P. Johnelle Sparks,Corey S. Sparks
International Journal of Population Research , 2012, DOI: 10.1155/2012/757538
Abstract: This paper assesses individual and social environment determinants of obesity in the adult Mexican population based on socioeconomic position, rural residence, and areal deprivation. Using a nationally representative health and nutrition survey, this analysis considers individual and structural determinants of obesity from a socioeconomic position and health disparities conceptual framework using multilevel logistic regression models. We find that more than thirty percent of Mexican adults were obese in 2006 and that the odds of being obese were strongly associated with an individual's socioeconomic position, gender, place of residence, and the level of marginalization (areal deprivation) in the place of residence. Surprisingly, areas of the country where areal deprivation was highest had lower risks of individual obesity outcomes. We suggest that programs oriented towards addressing the health benefits of traditional food systems over high-energy dense refined foods and sugary beverages be promoted as part of a public health program aimed at curbing the rising obesity prevalence in Mexico. 1. Introduction Major improvements in health and economic well-being have occurred over the past several decades in Mexico. However health care expenditures and resources are lower, and major health indicators, such as life expectancy and infant mortality rates, are higher in Mexico compared to other OECD countries [1]. Additionally, obesity prevalence rates are high and increasing in Mexico [2–5], with approximately 30 percent of the adult population obese [6]; only the US has a higher adult obesity rate than Mexico of all OECD countries [1]. Other studies estimate obesity prevalence to be as high as 50 percent of the population [7], and almost 70 percent of the adult Mexican population is either obese or overweight [6, 8]. Similar obesity prevalence rates have been observed between poor rural and urban adults in Mexico [9]; however gender differences have been noted for overweight and obesity prevalence for Mexican adults indicating a female overweight/obesity disadvantage [6, 7, 10]. The rise in obesity prevalence presents new implications for the health care needs of the Mexican population and longer-term chronic health problems, like diabetes and hypertension [8, 11], for a low-income country with high levels of inequality in economic, social service, and health resources [1]. Differences in economic resources, social services, physical infrastructure, health care services, and food environments exist across regions of Mexico [12–14], with noticeable differences
Measurements of the Yield Stress in Frictionless Granular Systems
Ning Xu,Corey S. O'Hern
Physics , 2005, DOI: 10.1103/PhysRevE.73.061303
Abstract: We perform extensive molecular dynamics simulations of 2D frictionless granular materials to determine whether these systems can be characterized by a single static yield shear stress. We consider boundary-driven planar shear at constant volume and either constant shear force or constant shear velocity. Under steady flow conditions, these two ensembles give similar results for the average shear stress versus shear velocity. However, near jamming it is possible that the shear stress required to initiate shear flow can differ substantially from the shear stress required to maintain flow. We perform several measurements of the shear stress near the initiation and cessation of flow. At fixed shear velocity, we measure the average shear stress $\Sigma_{yv}$ in the limit of zero shear velocity. At fixed shear force, we measure the minimum shear stress $\Sigma_{yf}$ required to maintain steady flow at long times. We find that in finite-size systems $\Sigma_{yf} > \Sigma_{yv}$, which implies that there is a jump discontinuity in the shear velocity from zero to a finite value when these systems begin flowing at constant shear force. However, our simulations show that the difference $\Sigma_{yf} - \Sigma_{yv}$, and thus the discontinuity in the shear velocity, tend to zero in the infinite system size limit. Thus, our results indicate that in the large system limit, frictionless granular systems are characterized by a single static yield shear stress. We also monitor the short-time response of these systems to applied shear and show that the packing fraction of the system and shape of the velocity profile can strongly influence whether or not the shear stress at short times overshoots the long-time average value.
Effective Temperatures in Athermal Systems Sheared at Fixed Normal Load
Ning Xu,Corey S. O'Hern
Physics , 2004, DOI: 10.1103/PhysRevLett.94.055701
Abstract: We perform molecular dynamics simulations of repulsive athermal systems sheared at fixed normal load to study the effective temperature $T_L$ defined from time-dependent fluctuation-dissipation relations for density. We show that these systems possess two distinct regimes as a function of the ratio $T_S/V$ of the granular temperature to the potential energy per particle. At small $T_S/V$, these systems are pressure-controlled and $T_L$ is set by the normal load. In contrast, they behave as quasi-equilibrium systems with $T_L \approx T_S$ that increases with shear rate at large $T_S/V$. These results point out several problems with using $T_L$ in thermodynamic descriptions of slowly sheared athermal systems.
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