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Large Pool (large + pool)
Selected AbstractsThe linkage between velocity patterns and sediment entrainment in a forced-pool and riffle unitEARTH SURFACE PROCESSES AND LANDFORMS, Issue 2 2009D. M. Thompson Abstract A field-based project was initiated in order to characterize velocities and sediment entrainment in a forced-pool and riffle sequence. Three-dimensional velocities and turbulence intensities were measured with an acoustic Doppler velocimeter at 222 different points at three similar flows that averaged approximately 4·35 m3 s,1 within a large pool,riffle unit on North Saint Vrain Creek, Colorado. Sediment-sorting patterns were observed with the introduction of 500 tracer particles painted according to initial seeding location. Tracer particles moved sporadically during a 113 day period in response to the annual snowmelt peak flow, which reached a maximum level of 14·8 m3 s,1. Velocity data indicate high instantaneous velocities and turbulence levels in the centre of pools. Patterns of sediment deposition support the notion that stream competence is higher in the pool than the downstream riffle. Flow convergence around a large channel constriction appears to play a major role in multiple processes that include helical flow development and sediment routing, and backwater development with low velocities and turbulence levels above the constriction that may locally limit sediment supply. Jet flow, flow separation, vortex scour and turbulence generation enhance scour in the centre of pools. Ultimately, multiple processes appear to play some role in maintenance of this forced pool and the associated riffle. Copyright © 2008 John Wiley & Sons, Ltd. [source] Origin and geochemistry of Miocene marine evaporites associated with red beds: Great Kavir Basin, Central IranGEOLOGICAL JOURNAL, Issue 1 2007Hossain Rahimpour-Bonab Abstract During the Cenozoic numerous shallow epicontinental evaporite basins formed due to tectonic movements in the Northern Province of the Central Iran Tectonic Zone (the Great Kavir Basin). During the Miocene, due to sea-level fluctuations, thick sequences of evaporites and carbonates accumulated in these basins that subsequently were overlain by continental red beds. Development of halite evaporites with substantial thickness in this area implies inflow of seawater along the narrow continental rift axis. The early ocean basin development was initiated in Early Eocene time and continued up to the Middle Miocene in the isolated failed rift arms. Competition between marine and non-marine environments, at the edge of the encroaching sea, produced several sequences of both abrupt and gradual transition from continental wadi sediments to marginal marine evaporites in the studied area. These evaporites show well-preserved textures indicative of relatively shallow-brine pools. The high Br content of these evaporites indicates marine-derived parent brines that were under the sporadic influence of freshening by meteoric water or replenishing seawater. However, the association of hopper and cornet textures denotes stratified brine that filled a relatively large pool and prevented rapid variations in the Br profile. Unstable basin conditions that triggered modification of parent brine chemistry prevailed in this basin and caused variable distribution patterns for different elements in the chloride units. The presence of sylvite and the absence of Mg-sulphate/chlorides in the paragenetic sequence indicate SO4,depleted parent brine in the studied sequence. Petrographic examinations along with geochemical analyses on these potash-bearing halites reveal parental brines which were a mixture of seawater and CaCl2 -rich brines. The source of CaCl2 -rich brines is ascribed to the presence of local rift systems in the Great Kavir Basin up to the end of the Early Miocene. Copyright © 2007 John Wiley & Sons, Ltd. [source] Trust in the Medical Profession: Conceptual and Measurement IssuesHEALTH SERVICES RESEARCH, Issue 5 2002Mark A Hall Objective. To develop and test a multi-item measure for general trust in physicians, in contrast with trust in a specific physician. Data Sources. Random national telephone survey of 502 adult subjects with a regular physician and source of payment. Study Design. Based on a multidimensional conceptual model, a large pool of candidate items was generated, tested, and revised using focus groups, expert reviewers, and pilot testing. The scale was analyzed for its factor structure, internal consistency, construct validity, and other psychometric properties. Principal Findings. The resulting 11-item scale measuring trust in physicians generally is consistent with most aspects of the conceptual model except that it does not include the dimension of confidentiality. This scale has a single-factor structure, good internal consistency (alpha=.89), and good response variability (range=11,54; mean=33.5; SD=6.9). This scale is related to satisfaction with care, trust in one's physician, following doctors' recommendations, having no prior disputes with physicians, not having sought second opinions, and not having changed doctors. No association was found with race/ethnicity. While general trust and interpersonal trust are qualitatively similar, they are only moderately correlated with each other and general trust is substantially lower. Conclusions. Emerging research on patients' trust has focused on interpersonal trust in a specific, known physician. Trust in physicians in general is also important and differs significantly from interpersonal physician trust. General physician trust potentially has a strong influence on important behaviors and attitudes, and on the formation of interpersonal physician trust. [source] A solution approach for log truck scheduling based on composite pricing and branch and boundINTERNATIONAL TRANSACTIONS IN OPERATIONAL RESEARCH, Issue 5 2003Myrna Palmgren Abstract The logging truck scheduling problem is one of the most complex routing problems where both pick-up and delivery operations are included. It consists in finding one feasible route for each vehicle in order to satisfy the demands of the customers and in such a way that the total transport cost is minimized. We use a mathematical formulation of the log truck scheduling problem where each column represents a feasible route. We generate a large pool of columns based on solving a transportation problem. Then we apply a composite pricing algorithm, which mainly consists of pricing the pool of columns and maintain an active set of these, for solving the LP relaxed model. A branch and price approach is used to obtain integer solutions in which we apply composite pricing to generate new columns. Numerical results from case studies at Swedish forestry companies are presented. [source] The use of (GTG)5 oligonucleotide as an RAPD primer to type Campylobacter concisusLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2006M.I. Matsheka Abstract Aim:, DNA fingerprinting using (GTG)5 oligonucleotide as a primer in a random amplified polymorphic DNA (RAPD) assay was assessed by typing isolates of Campylobacter concisus strains, collected over a period of 8 years. Methods and Results:, RAPD analysis using the (GTG)5 oligonucleotide as a primer was used to type 100 isolates of C. concisus comprising mostly isolates from children with diarrhoea. Using this method, 86% of the isolates were found to be genotypically diverse. Of these heterogeneous isolates, 25 of the strains were also shown to be genetically distinct in a previous study using pulsed field gel electrophoresis. The remaining isolates (14) could be classified into five profile groups based on the DNA fingerprinting patterns. The assay successfully identified epidemiologically linked strains from the unrelated genetically diverse pool of strains. Conclusions:, Laboratory RADP typing using the (GTG)5 primer proved to be useful in distinguishing related strains of C. concisus from a large pool of unrelated strains of this organism. Significance and Impact of the Study:, RAPD typing using (GTG)5 is a simple method that could be used to investigate the epidemiology of C. concisus. The results suggest that homologous lineages of C. concisus may exist within an otherwise heterogeneous species complex. However, these data need to be confirmed using a more robust typing method. [source] Effectiveness of medical school admissions criteria in predicting residency ranking four years laterMEDICAL EDUCATION, Issue 1 2007Christopher Peskun Background, Medical schools across Canada expend great effort in selecting students from a large pool of qualified applicants. Non-cognitive assessments are conducted by most schools in an effort to ensure that medical students have the personal characteristics of importance in the practice of Medicine. We reviewed the ability of University of Toronto academic and non-academic admission assessments to predict ranking by Internal Medicine and Family Medicine residency programmes. Methods, The study sample consisted of students who had entered the University of Toronto between 1994 and 1998 inclusive, and had then applied through the Canadian resident matching programme to positions in Family or Internal Medicine at the University of Toronto in their graduating year. The value of admissions variables in predicting medical school performance and residency ranking was assessed. Results, Ranking in Internal Medicine correlated significantly with undergraduate grade point average (GPA) and the admissions non-cognitive assessment. It also correlated with 2-year objective structured clinical examination (OSCE) score, clerkship grade in Internal Medicine, and final grade in medical school. Ranking in Family Medicine correlated with the admissions interview score. It also correlated with 2nd-year OSCE score, clerkship grade in Family Medicine, clerkship ward evaluation in Internal Medicine and final grade in medical school. Discussion, The results of this study suggest that cognitive as well as non-cognitive factors evaluated during medical school admission are important in predicting future success in Medicine. The non-cognitive assessment provides additional value to standard academic criteria in predicting ranking by 2 residency programmes, and justifies its use as part of the admissions process. [source] The role of thermodynamics in disc fragmentationMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 3 2009Dimitris Stamatellos ABSTRACT Thermodynamics play an important role in determining the way a protostellar disc fragments to form planets, brown dwarfs and low-mass stars. We explore the effect that different treatments of radiative transfer have in simulations of fragmenting discs. Three prescriptions for the radiative transfer are used: (i) the diffusion approximation of Stamatellos et al.; (ii) the barotropic equation of state (EOS) of Goodwin et al. and (iii) the barotropic EOS of Bate et al. The barotropic approximations capture the general evolution of the density and temperature at the centre of each proto-fragment but (i) they do not make any adjustments for particular circumstances of a proto-fragment forming in the disc and (ii) they do not take into account thermal inertia effects that are important for fast-forming proto-fragments in the outer disc region. As a result, the number of fragments formed in the disc and their properties are different, when a barotropic EOS is used. This is important not only for disc studies but also for simulations of collapsing turbulent clouds, as in many cases in such simulations stars form with discs that subsequently fragment. We also examine the difference in the way proto-fragments condense out in the disc at different distances from the central star using the diffusion approximation and following the collapse of each proto-fragment until the formation of the second core (,, 10,3 g cm,3). We find that proto-fragments forming closer to the central star tend to form earlier and evolve faster from the first to the second core than proto-fragments forming in the outer disc region. The former have a large pool of material in the inner disc region that they can accrete from and grow in mass. The latter accrete more slowly and they are hotter because they generally form in a quick abrupt event. [source] Epidemiologic research on man-made disasters: Strategies and implications of cohort definition for World Trade Center worker and volunteer surveillance programMOUNT SINAI JOURNAL OF MEDICINE: A JOURNAL OF PERSONALIZED AND TRANSLATIONAL MEDICINE, Issue 2 2008David A. Savitz PhD Abstract Studies of long-term health consequences of disasters face unique methodologic challenges. The authors focused on studies of the health of cleanup and recovery workers, who are often poorly enumerated at the outset and difficult to follow over time. Comparison of the experience at the World Trade Center disaster with 4 past incidents of chemical and radiation releases at Seveso, Italy; Bhopal, India; Chernobyl, Ukraine; and Three Mile Island, USA, provided useful contrasts. Each event had methodologic advantages and disadvantages that depended on the nature of the disaster and the availability of records on area residents, and the emergency-response and cleanup protocol. The World Trade Center Worker Monitoring Program has well-defined eligibility criteria but lacks information on the universe of eligible workers to characterize response proportions or the potential for distortion of reported health effects. Nonparticipation may result from lack of interest, lack of awareness of the program, availability of another source of medical care, medical conditions precluding participation, inability to take time off from work, moving out of the area, death, or shift from initially ineligible to eligible status. Some of these considerations suggest selective participation by the sickest individuals, whereas others favor participation by the healthiest. The greatest concern with the validity of inferences regarding elevated health risks relative to external populations is the potential for selective enrollment among those who are affected. If there were a large pool of nonparticipating workers and those who suffered ill health were most motivated to enroll, the rates of disease among participants would be substantially higher than among all those eligible for the program. Future disaster follow-up studies would benefit substantially by having access to accurate estimates of the number of workers and information on the individuals who contributed to the cleanup and recovery effort. Mt Sinai J Med 75:77,87, 2008© 2008 Mount Sinai School of Medicine [source] Ethics and Genetic Selection in Purebred DogsREPRODUCTION IN DOMESTIC ANIMALS, Issue 1 2003VN Meyers-Wallen Contents There is an ongoing revolution in medicine that is changing the way that veterinarians will be counselling clients regarding inherited disorders. Clinical applications will emerge rapidly in veterinary medicine as we obtain new information from canine and comparative genome projects (Meyers-Wallen 2001: Relevance of the canine genome project to veterinary medical practice. International Veterinary Information Service, New York). The canine genome project is described by three events: mapping markers on canine chromosomes, mapping gene locations on canine chromosomes (Breen et al. 2001: Genome Res. 11, 1784,1795), and obtaining the nucleotide sequence of the entire canine genome. Information from such research has provided a few DNA tests for single gene mutations [Aguirre 2000: DNA testing for inherited canine diseases. In: Bonagura, J (ed), Current Veterinary Therapy XIII. Philadelphia WB Saunders Co, 909,913]. Eventually it will lead to testing of thousands of genes at a time and production of DNA profiles on individual animals. The DNA profile of each dog could be screened for all known genetic disease and will be useful in counselling breeders. As part of the pre-breeding examination, DNA profiles of prospective parents could be compared, and the probability of offspring being affected with genetic disorders or inheriting desirable traits could be calculated. Once we can examine thousands of genes of individuals easily, we have powerful tools to reduce the frequency of, or eliminate, deleterious genes from a population. When we understand polygenic inheritance, we can potentially eliminate whole groups of deleterious genes from populations. The effect of such selection on a widespread basis within a breed could rapidly improve health within a few generations. However, until we have enough information on gene interaction, we will not know whether some of these genes have other functions that we wish to retain. And, other population effects should not be ignored. At least initially it may be best to use this new genetic information to avoid mating combinations that we know will produce affected animals, rather than to eliminate whole groups of genes from a population. This is particularly important for breeds with small gene pools, where it is difficult to maintain genetic diversity. Finally, we will eventually have enough information about canine gene function to select for specific genes encoding desirable traits and increase their frequencies in a population. This is similar to breeding practices that have been applied to animals for hundreds of years. The difference is that we will have a large pool of objective data that we can use rapidly on many individuals at a time. This has great potential to improve the health of the dog population as a whole. However, if we or our breeder clients make an error, we can inadvertently cause harm through massive, rapid selection. Therefore, we should probably not be advising clients on polygenic traits or recommend large scale changes in gene frequencies in populations until much more knowledge of gene interaction is obtained. By then it is likely that computer modelling will be available to predict the effect of changing one or several gene frequencies in a dog population over time. And as new mutations are likely to arise in the future, these tools will be needed indefinitely to detect, treat and eliminate genetic disorders from dog populations. Information available from genetic research will only be useful in improving canine health if veterinarians have the knowledge and skills to use it ethically and responsibly. There is not only a great potential to improve overall canine health through genetic selection, but also the potential to do harm if we fail to maintain genetic diversity. Our profession must be in a position to correctly advise clients on the application of this information to individual dogs as well as to populations of dogs, and particularly purebred dogs. [source] Kidney Transplantation Using Elderly Non-Heart-Beating Donors: A Single-Center ExperienceAMERICAN JOURNAL OF TRANSPLANTATION, Issue 5p1 2006M. G. J. Snoeijs Although acceptable outcomes have been reported in both non-heart-beating (NHB) and elderly donors individually, the large pool of elderly NHB donors has not yet been fully utilized. In 1994, we expanded our transplant protocol to include NHB donors aged over 65 years and this study compares the clinical outcomes with regular NHB transplantations. Up to June 2005, 24 patients were transplanted at our center with kidneys from NHB donors aged 65 years or more, whereas 176 patients received grafts from conventional NHB donors during the same period. Grafts from older donors were associated with inferior glomerular filtration rates (29 vs. 44 mL/min after 1 year, p = 0.01) and graft survival (52% vs. 68% after 5 years, p = 0.19) compared to younger NHB donor grafts, although the difference in graft survival was not statistically significant. Exclusion of older NHB donor kidneys with severe vascular pathology resulted in similar graft survival of older and younger NHB donor kidneys. We conclude that the use of elderly NHB donors in order to expand the donor pool was associated with unacceptable clinical outcomes and cannot be justified without further refinement in their selection, for example, by histological assessment of pretransplant biopsies. [source] Reconciling pedagogy and health sciences to promote Indigenous healthAUSTRALIAN AND NEW ZEALAND JOURNAL OF PUBLIC HEALTH, Issue 2 2000Denise Main Objectives: To increase knowledge and skills regarding Indigenous learning styles. To raise awareness within the tertiary education sector that Aboriginal students learn differently and that Indigenous cultures and pedagogy have validity and strength. To examine pedagogical strategies that assist both tertiary students capacity for learning and university lecturers' delivery and evaluation of teaching and learning strategies. Methods: A qualitative, ethnographic framework using personal observations, field and classroom experience, interviews and review of literature in the fields of education, public health and Indigenous cultural perspectives. Results: Aboriginal people are the receivers of services and programs that will be delivered, in the majority of cases, by university-educated, non-Aboriginal, professional health care providers. Indigenous students face specific challenges in obtaining an effective education for working in the Aboriginal and wider community in the field of public health; the challenges relate to culture, health paradigms and community. Conclusion: Lecturers in health and human science courses for Aboriginal students need to both examine and appreciate the cultural constraints on learning faced by their students within the context of mainstream curriculum, and to build on the large pool of knowledge and learning styles that Aboriginal society bequeaths to Aboriginal students. Implications: Academics can apply the cultural differences and knowledge base of the Indigenous community as a force to promote health through learning. [source] A Counterfactual Analysis on Unlimited Surplus Labor in Rural ChinaCHINA AND WORLD ECONOMY, Issue 1 2008Fang Cai J21; J22; J24; O33 Abstract Using a counterfactual analysis approach, the present paper examines a host of conventional wisdoms relating to issues of farmer, the countryside and agriculture, which are believed to be all originated from the existence of mass surplus laborers in China. When analyzing various sources of statistics, evidence shows that there is no longer a large pool of surplus laborers in rural China as most people believe. Based on this counterfactual result, all related events, such as the direction of agricultural technological changes, the level of comparative productivity of agricultural labor, and the degree of rural-urban income gap must be reconsidered. [source] | ||||||||||||||||