12,749 research outputs found
HEALTH AND SAFETY REGULATION OF SMALL, HIGH-RISK SUBPOPULATIONS
The choice of decision framework used to set regulatory tolerance levels for hazardous substances can be divided into rigid and flexible tolerance levels. Rigid decision frameworks include zero or deminimis that fix risk levels for some subpopulation. and/or highly tolerances The accelerating identification of highly sensitive exposed individuals and the division of the population into ever smaller subpopulations at higher risk could prove to be tremendously burdensome on regulatory systems, particularly for rigid decision frameworks. Rigid tolerance levels, philosophically based on "rights" to zero or arbitrarily low excess risks for individuals, do not contain sufficient flexibility to account for small high-risk subpopulations. Furthermore, the equal protection for all such groups is an illusion, mainly because of the potentially large number of such subgroups and the relatively fixed regulatory resources. Thus, deminimis regulation is seen as a minimal but inadequate improvement over zero risk regulation. with improved measures of the heterogeneous demand for risk reduction by various high-risk subpopulations, augmented cost-benefit analyses leading to flexible tolEr2.nces could provide a richer analytic framework for more efficient regulatory decisions. Additionally, it may be useful to attempt to c2.tegorize hazards and subpopulations on the basis of the ability to self-protect.De minimis, sensitive, decision framework, cost benefit, Food Consumption/Nutrition/Food Safety, Health Economics and Policy,
Effects of Anisotropy in QED3 from Dyson-Schwinger equations in a box
We investigate the effect of anisotropies in the fermion velocities of 2+1
dimensional QED on the critical number N_f^c of fermions for dynamical mass
generation. Our framework are the Dyson-Schwinger equations for the gauge boson
and fermion propagators formulated in a finite volume. In contrast to previous
Dyson-Schwinger studies we do not rely on an expansion in small anisotropies
but keep the full velocity dependence of fermion equations intact. As result we
find sizable variations of N_f^c away from the isotropic point in agreement
with other approaches. We discuss the relevance of our findings for models of
high-T_c superconductors.Comment: 9 pages, 7 figures, v2: minor changes, typos corrected, version
accepted by PR
Assessment of Timber Resource Values in Arkansas
The Arkansas forest lands have long been and will continue to be an important contributor to the state\u27s economy. Today, Arkansas forests cover 52 percent of the land area (Hines and Vissage, 1988). These forests are classified by physiographic characteristics into four timber regions. The timber removed from forested lands provides direct and indirect employment for approximately 40,000 people within the Arkansas manufacturing sector (Kluender and Willett, 1989). This paper describes county and region level information, identifies standing timber volumes, net annual timber growth, net annual timber removals, and associated dollar values. Timber stand data are used to determine areas suitable for new facilities or expanding existing wood-based manufacturing facilities. This study also identifies opportunities within each region for wood-based manufacturing growth
Improving the Design and Operational Efficiency of Mineral Processes using in-Situ Tomography
Methods for achieving radical improvements to the separat-ion and environmental efficiency of mineral processing rely upon availability of totally new treatment methods, incremental enhancements of existing processes and intro-duction of best practice in operation and control. This review paper describes examples of the utilisation of process tomographic methods to achieve these objectives, based on some case study examples relevant to coal, meta-llic and industrial minerals
Health Transfers: An Application of Health-Health Analysis to Assess Food Safety Regulations
The authors apply a Health-Health Analysis to risks associated with harvesting Gulf oysters to evaluate that approach to managing health and safety risks
Post-Katrina Retention of Law Enforcement Officers: A Case Study of the New Orleans Police Department
This dissertation is a case study of the New Orleans Police Department and identified factors that affected the retention of law enforcement officers post-Hurricane Katrina. The NOPD was chosen because the agency was an extreme case and experienced the unprecedented separation of over 300 officers during and post- Hurricane Katrina. The variables examined included tenure, age, salary, education, and job satisfaction, as well as, race, sex, marital status, and New Orleans residency.
This research is significant because in a time of decreasing budgets and increased cost to replace employees, where skills are scarce and knowledge is important, recruitment is costly, and it takes time to fill vacancies, turnover can be problematic (Loquercio, 2006). Hurricane Katrina was an unprecedented catastrophic disaster unlike any event experienced by a local police department. The impact accelerated the attrition of New Orleans Police Department officers at a time when the agency and community needed them the most. In addition to normal retention challenges experienced by law enforcement, post-Hurricane Katrina, the New Orleans Police Department experienced separation of almost a fourth of its agency post-Hurricane Katrina. This was very problematic and forced the department to operate severely short-staffed at a time when the department was trying to provide essential services to the community and recover from the storm’s affect at the same time. This dissertation explored some of the causes of attrition, examined the attrition of the NOPD pre-and post-Hurricane Katrina, and reasons most officers stayed. It was important to identify lessons learned from an agency and officers who experienced a disaster and unprecedented attrition of officers first hand. The consequences of such significant attrition will take years to overcome, especially in light of the New Orleans Police Department’s pre-and post-Hurricane Katrina recruitment and retention challenges
Post-Katrina Retention of Law Enforcement Officers: A Case Study of the New Orleans Police Department
This dissertation is a case study of the New Orleans Police Department and identified factors that affected the retention of law enforcement officers post-Hurricane Katrina. The NOPD was chosen because the agency was an extreme case and experienced the unprecedented separation of over 300 officers during and post- Hurricane Katrina. The variables examined included tenure, age, salary, education, and job satisfaction, as well as, race, sex, marital status, and New Orleans residency.
This research is significant because in a time of decreasing budgets and increased cost to replace employees, where skills are scarce and knowledge is important, recruitment is costly, and it takes time to fill vacancies, turnover can be problematic (Loquercio, 2006). Hurricane Katrina was an unprecedented catastrophic disaster unlike any event experienced by a local police department. The impact accelerated the attrition of New Orleans Police Department officers at a time when the agency and community needed them the most. In addition to normal retention challenges experienced by law enforcement, post-Hurricane Katrina, the New Orleans Police Department experienced separation of almost a fourth of its agency post-Hurricane Katrina. This was very problematic and forced the department to operate severely short-staffed at a time when the department was trying to provide essential services to the community and recover from the storm’s affect at the same time. This dissertation explored some of the causes of attrition, examined the attrition of the NOPD pre-and post-Hurricane Katrina, and reasons most officers stayed. It was important to identify lessons learned from an agency and officers who experienced a disaster and unprecedented attrition of officers first hand. The consequences of such significant attrition will take years to overcome, especially in light of the New Orleans Police Department’s pre-and post-Hurricane Katrina recruitment and retention challenges
Champagne Flutes and Brandy Snifters: Modelling Protostellar Outflow-Cloud Chemical Interfaces
A rich variety of molecular species has now been observed towards hot cores
in star forming regions and in the interstellar medium. An increasing body of
evidence from millimetre interferometers suggests that many of these form at
the interfaces between protostellar outflows and their natal molecular clouds.
However, current models have remained unable to explain the origin of the
observational bias towards wide-angled "brandy snifter" shaped outflows over
narrower "champagne flute" shapes in carbon monoxide imaging. Furthermore,
these wide-angled systems exhibit unusually high abundances of the molecular
ion HCO. We present results from a chemo-dynamic model of such regions
where a rich chemistry arises naturally as a result of turbulent mixing between
cold, dense molecular gas and the hot, ionized outflow material. The injecta
drives a rich and rapid ion-neutral chemistry in qualitative and quantitative
agreement with the observations. The observational bias towards wide-angled
outflows is explained naturally by the geometry-dependent ion injection rate
causing rapid dissociation of CO in the younger systems.Comment: Accepted to MNRAS. 12 pages, 8 Figure
Stretching single polysaccharide molecules using AFM: A potential method for the investigation of the intermolecular uronate distribution of alginate?
Illustrative examples of the way in which the molecular force-extension behaviour of polysaccharides is governed by the nature of the linkage between their constituent pyranose rings are presented for a series of standard homopolymers. These results agree with previously proposed general hypotheses regarding the possibility of generating force-induced conformational transitions, and with the predictions of a model in which the inter-conversion of pyranose conformers is assumed to be an equilibrium process on the timescale of the molecular stretching. Subsequently, we investigate the potential of the technique in the characterisation of co-polymeric polysaccharides in which the nature of the glycan linkages is different between the two distinct residue types. Specifically, we explore the possibility that the ratio of mannuronic acid (M) to guluronic acid (G) in alginate chains will be reflected in their single molecule stretching behaviour, owing to their contrasting equatorial and axial linkages. Furthermore, as the technique described interrogates the sample one polymer at a time we outline the promise of, and the obstacles to, obtaining a new level of characterisation using this methodology where differences observed in the single molecule stretching curves obtained from single alginate samples reflectsomething of the real intermolecular distribution of the M / G ratio
Pacific Ocean Forcing and Atmospheric Variability are the Dominant Causes of Spatially Widespread Droughts in the Contiguous United States
The contributions of oceanic and atmospheric variability to spatially widespread summer droughts in the contiguous United States (hereafter, pan-CONUS droughts) are investigated using 16-member ensembles of the Community Climate Model version 3 (CCM3) forced with observed sea surface temperatures (SSTs) from 1856 to 2012. The employed SST forcing fields are either (i) global or restricted to the (ii) tropical Pacific or (iii) tropical Atlantic to isolate the impacts of these two ocean regions on pan-CONUS droughts. Model results show that SST forcing of pan-CONUS droughts originates almost entirely from the tropical Pacific because of atmospheric highs from the northern Pacific to eastern North America established by La Nia conditions, with little contribution from the tropical Atlantic. Notably, in all three model configurations, internal atmospheric variability influences pan-CONUS drought occurrence by as much or more than the ocean forcing and can alone cause pan-CONUS droughts by establishing a dominant high centered over the US montane West. Similar results are found for the Community Atmosphere Model version 5 (CAM5). Model results are compared to the observational record, which supports model-inferred contributions to pan-CONUS droughts from La Nias and internal atmospheric variability. While there may be an additional association with warm Atlantic SSTs in the observational record, this association is ambiguous due to the limited number of observed pan-CONUS. The ambiguity thus opens the possibility that the observational results are limited by sampling over the 20th-century and not at odds with the suggested dominance of Pacific Ocean forcing in the model ensembles
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