200 resultados para Likelihood principle


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Access to basic health services was affirmed as a fundamental human right in the Declaration of Alma-Ata in 1978. The model formally adopted for providing healthcare services was primary health care (PHC), which involved universal, community-based preventive and curative services, with substantial community involvement. PHC,did not achieve its goals for several reasons, including the refusal of experts and politicians in developed countries to accept the principle that communities should plan and implement their own heathcare services. Changes in economic philosophy led to the replacement of PHC by Health Sector Reform, based on market forces and the economic benefits of better health. It is time to abandon economic ideology and determine the methods that will provide access to basic healthcare services for all people.

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In this paper, genetic algorithm (GA) is applied to the optimum design of reinforced concrete liquid retaining structures, which comprise three discrete design variables, including slab thickness, reinforcement diameter and reinforcement spacing. GA, being a search technique based on the mechanics of natural genetics, couples a Darwinian survival-of-the-fittest principle with a random yet structured information exchange amongst a population of artificial chromosomes. As a first step, a penalty-based strategy is entailed to transform the constrained design problem into an unconstrained problem, which is appropriate for GA application. A numerical example is then used to demonstrate strength and capability of the GA in this domain problem. It is shown that, only after the exploration of a minute portion of the search space, near-optimal solutions are obtained at an extremely converging speed. The method can be extended to application of even more complex optimization problems in other domains.

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The present study describes patterns of co-morbidity between alcohol use and other substance use problems in the Australian population using data from the 1997 National Survey of Mental Health and Well-Being. Multiple regression analyses examined whether the observed associations between alcohol and other drug use disorders were explained by other variables, including demographic characteristics and neuroticism. We also assessed whether the presence of co-morbid substance use disorders affected treatment seeking for a mental health problem. Alcohol use was related strongly to the use of other substances. Those who did not report alcohol use within the past 12 months were less likely to report using tobacco, cannabis, sedatives, stimulants or opiates. Higher rates again were observed among those with alcohol use disorders: half (51%) of those who were alcohol-dependent were regular tobacco smokers, one-third had used cannabis (32%); 15% reported other drug use; 15% met criteria for a cannabis use disorder and 7% met criteria for another drug use disorder. These associations were not accounted for by the demographic and other variables considered here. Co-morbid substance use disorders (sedatives, stimulants or opioids) predicted a high likelihood of seeking treatment for a mental health problem among alcohol-dependent people.

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We previously showed that 16-day-old rats exposed to a relatively high dose of ethanol at 10-15 postnatal days of age have fewer neurons in the hilus region of the hippocampus compared with controls. Dentate gyrus granule cell numbers, however, showed no statistically significant changes attributable to the ethanol treatment. It is possible that some of the changes in brain morphology, brought about as a result of the exposure to ethanol during early life, may not be manifested until later in life. This question has been further addressed in an extension to our previous study. Wistar rats were exposed to a relatively high daily dose of ethanol on postnatal days 10-15 by placement in a chamber containing ethanol vapour, for 3 h/day. The blood ethanol concentration was found to be similar to430 mg/dl at the end of the period of exposure. Groups of ethanol-treated (ET), separation control (SC), and mother-reared control (MRC) rats were anaesthetised and killed either at 16 or 30 days of age by perfusion with phosphate-buffered 2.5% glutaraldehyde. The Cavalieri principle and the physical disector methods were used to estimate, respectively, the regional volumes and neuron cell numerical densities in the hilus and granule cell regions of the dentate gyrus. The total numbers of neurons in the hilus region and granule cell layer were computed from these estimates. It was found that 16-day-old animals had 398,000-441,000 granule cells, irrespective of group. The numbers of granule cells increased such that by 30 days of age, rats had 487,000-525,500 granule cells. However, there were no significant differences between ethanol-treated rats and their age-matched controls in granule cell numbers. In contrast, ethanol-treated rats had slightly but significantly fewer neurons in the hilus region than did control animals at 16 days of age, but not at 30 days of age. Therefore, it appears that a short period of ethanol exposure during early life can have effects on neuron numbers of some hippocampal neurons, but not others. The effects on hilar neuron numbers, observed as a result of such short periods of ethanol treatment, appeared to be transitory. (C) 2003 Wiley-Liss, Inc.

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Controversy still exists regarding the biological function of granzyme serine proteases released with perforin from the cytotoxic granules of NK cells and CTLs. In particular, it is not clear whether the major granzymes, A and A play an essential role in tumor rejection mediated by the perforin pathway. We have now examined the relative importance of perforin and granzyme A and B clusters in five different tumor models that stringently distinguish their importance. We conclude that granzyme A and B clusters are not essential for CTL- and NK cell-mediated rejection of spontaneous and experimental tumors, raising the likelihood that either perforin alone or in combination with an additional granzyme or granule component(s) mediates cytotoxicity of tumor cells in vivo.

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Objective: To determine the factors associated with general practitioners' current practice location, with particular emphasis on rural location. Design: Observational, retrospective, case-control study using a self-administered questionnaire. Setting: Australian general practices in December 2000. Participants: 2414 Australian-trained rural and urban GPs. Main outcome measure: Current urban or rural practice location. Results: For Australia as a whole, rural GPs were more likely to be male (odds ratio [OR], 1.42; 95% CI, 1.17-1.73), Australian-born (OR, 1.95; 95% CI, 1.55-2.45), and to report attending a rural primary school for some (OR, 2.21; 95% CI, 1.69-2.89) or all (OR, 2.79; 95% CI, 1.94-4.00) of their primary schooling. Rural GPs' partners or spouses were also more likely to report some (OR, 2.75; 95% CI, 2.07-3.66) or all (OR, 2.86; 95% CI, 2.02-4.05) rural primary schooling. A rural background in both GP and partner produced the highest likelihood of rural practice (OR, 6.28; 95% CI, 4.26-9.25). For individual jurisdictions, a trend towards more rural GPs being men was only significant in Tasmania. In all jurisdictions except Tasmania and the Northern Territory, rural GPs were more likely to be Australian-born. Conclusions: GPs' and their partners' rural background (residence and primary and secondary schooling) influences choice of practice location, with partners' background appearing to exert more influence.

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The phylogeny of the Australian legume genus Daviesia was estimated using sequences of the internal transcribed spacers of nuclear ribosomal DNA. Partial congruence was found with previous analyses using morphology, including strong support for monophyly of the genus and for a sister group relationship between the clade D. pachyloma and the rest of the genus. A previously unplaced bird-pollinated species, anceps + D. D. epiphyllum, was well supported as sister to the only other bird-pollinated species in the genus, D. speciosa, indicating a single origin of bird pollination in their common ancestor. Other morphological groups within Daviesia were not supported and require reassessment. A strong and previously unreported sister clade of Daviesia consists of the two monotypic genera Erichsenia and Viminaria. These share phyllode-like leaves and indehiscent fruits. The evolutionary history of cord roots, which have anomalous secondary thickening, was explored using parsimony. Cord roots are limited to three separate clades but have a complex history involving a small number of gains (most likely 0-3) and losses (0-5). The anomalous structure of cord roots ( adventitious vascular strands embedded in a parenchymatous matrix) may facilitate nutrient storage, and the roots may be contractile. Both functions may be related to a postfire resprouting adaptation. Alternatively, cord roots may be an adaptation to the low-nutrient lateritic soils of Western Australia. However, tests for association between root type, soil type, and growth habit were equivocal, depending on whether the variables were treated as phylogenetically dependent (insignificant) or independent ( significant).

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Objective To determine the association between rural undergraduate training, rural postgraduate training and medical school entry criteria favouring rural students, on likelihood of working in rural Australian general practice. Methods National case - control study of 2414 rural and urban general practitioners (GPs) sampled from the Health Insurance Commission database. Participants completed a questionnaire providing information on demographics, current practice location and rural undergraduate and postgraduate experience. Results Rural GPs were more likely to report having had any rural undergraduate training [ odds ratio ( OR) 1.61, 95% confidence interval (CI) 1.32 - 1.95] than were urban GPs. Rural GPs were much more likely to report having had rural postgraduate training ( OR 3.14, 95% CI 2.57 - 3.83). As the duration of rural postgraduate training increased so did the likelihood of working as a rural GP: those reporting that more than half their postgraduate training was rural were most likely to be rural GPs ( OR 10.52, 95% CI 5.39 - 20.51). South Australians whose final high school year was rural were more likely to be rural GPs ( OR 3.18, 95% CI 0.99 - 10.22). Conclusions Undergraduate rural training, postgraduate training and medical school entry criteria favouring rural students, all are associated with an increased likelihood of being a rural GP. Longer rural postgraduate training is more strongly associated with rural practice. These findings argue for continuation of rural undergraduate training opportunities and rural entry schemes, and an expansion in postgraduate training opportunities for GPs.

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In experiments on isolated animal muscle, the force produced during active lengthening contractions can be up to twice the isometric force, whereas in human experiments lengthening force shows only modest, if any, increase in force. The presence of synergist and antagonist muscle activation associated with human experiments in situ may partly account for the difference between animal and human studies. Therefore, this study aimed to quantify the force-velocity relationship of the human soleus muscle and assess the likelihood that co-activation of antagonist muscles was responsible for the inhibition of torque during submaximal voluntary plantar flexor efforts. Seven subjects performed submaximal voluntary lengthening, shortening(at angular, velocities of +5, -5, +15, -15 and +30, and -30degrees s(-1)) and isometric plantar flexor efforts against an ankle torque motor. Angle-specific (90degrees) measures of plantar flexor torque plus surface and intramuscular electromyography from soleus, medial gastrocnemius and tibialis anterior were made. The level of activation (30% of maximal voluntary isometric effort) was maintained by providing direct visual feedback of the soleus electromyogram to the subject. In an attempt to isolate the contribution of soleus to the resultant plantar flexion torque, activation of the synergist and antagonist muscles were minimised by: (1) flexing the knee of the test limb, thereby minimising the activation of gastrocnemius, and (2) applying an anaesthetic block to the common peroneal nerve to eliminate activation of the primary antagonist muscle, tibialis anterior and the synergist muscles, peroneus longus and peroneus brevis. Plantar flexion torque decreased significantly (P<0.05) after blocking the common peroneal nerve which was likely due to abolishing activation of the peroneal muscles which are synergists for plantar flexion. When normalised to the corresponding isometric value, the force-velocity relationship between pre- and post-block conditions was not different. In both conditions, plantar flexion torques during shortening actions were significantly less than the isometric torque and decreased at faster velocities. During lengthening actions, however, plantar flexion torques were not significantly different from isometric regardless of angular velocity. It was concluded that the apparent inhibition of lengthening torques during voluntary activation is not due to co-activation of antagonist muscles. Results are presented as mean (SEM).

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Medication errors are a leading cause of unintended harm to patients in Australia and internationally. Research in this area has paid relatively little attention to the interactions between organisational factors and violations of procedures in producing errors, although violations have been found to increase the likelihood of these errors. This study investigated the role of organisational factors in contributing to violations by nurses when administering medications. Data were collected using a self-report questionnaire completed by 506 nurses working in either rural or remote areas in Queensland, Australia. This instrument was used to develop a path model wherein organisational variables predicted 21% of the variance in self-reported violations. Expectations of medical officers mediated the relationship between working conditions of nursing staff and violation behaviour.

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Slumping of hardsetting seedbeds upon wetting has not been extensively studied despite the likelihood that it determines the physical properties after drying. Slumping results from processes similar to those involved in crusting except that overburden pressure can dominate rather than rainfall kinetic energy. Only a few studies have dealt with the morphological description of slumping. To simulate different climatic and management conditions, repacked seedbeds of a hardsetting sandy-loam soil were subjected to a range of wetting conditions, e.g. capillary rise, immersion, and rainfall simulation. Slumping processes were characterized using qualitative and quantitative micromorphological observations of polished blocks and thin sections from resin-impregnated samples. A morphogenetical framework was proposed to help description of the complex associations of processes which can lead to structural collapse (crusting and slumping) on wetting. Three main stages were considered, i.e. aggregate disruption or abrasion, relocation of the released material, and compaction. In the hardsetting material studied here, structural collapse under slow wetting occurred at the bottom of cores due to aggregate coalescence under overburden pressure. Coalescence required aggregate cohesion being reduced by microcracking; therefore, it differed from the coalescence previously described in unstable silty loam soils where microcracking was not necessary for aggregates to coalesce. Macroporosity decreased most strongly under fast wetting due to physical dispersion and aggregate breakdown. Under simulated rainfall, compaction by raindrops could not be distinguish from aggregate breakdown. The role of overburden pressure and of rainfall kinetic energy remains to be stated; new data are required including measurement of total porosity in the initial, wet, and dry states. (C) 2003 Elsevier B.V. All rights reserved.

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We model a buyer who wishes to combine objects owned by two separate sellers in order to realize higher value. Sellers are able to avoid entering into negotiations with the buyer, so that the order in which they negotiate is endogenous. Holdout occurs if at least one of the sellers is not present in the first round of negotiations. We demonstrate that complementarity of the buyer's technology is a necessary condition for equilibrium holdout. Moreover, a rise in complementarity leads to an increased likelihood of holdout, and an increased efficiency loss. Applications include patents, the land assembly problem, and mergers.

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We have previously shown that exposing rats to a relatively high dose of ethanol during early postnatal life can result in an alteration in spatial learning ability. The hippocampal formation is known to be involved in the control of this ability. The purpose of the present study was to determine whether exposure of rats to ethanol during early postnatal life had either immediate or delayed effects on the numbers of pyramidal cells in the CA1-CA3 subregion of the hippocampus. Wistar rats were exposed to a relatively high daily dose of ethanol at postnatal day 10-15 by placing them for 3 h/day in a chamber containing ethanol vapor. Groups of ethanol-treated (ET), separation control (SC), and mother-reared control (MRC) rats were anesthetized and killed at 16 and 30 days of age by perfusion with phosphate-buffered 2.5% glutaraldehyde. The Cavalieri principle was used to determine the volumes of the CA1 and CA2+CA3 regions. The physical disector method was used to estimate the numerical density of neurons in each of the subdivisions. The total number of pyramidal cells was calculated by multiplying the appropriate estimates of the numerical density by the volume. There were significant age-related reductions in the total numbers of pyramidal cells at 16-30 days of age irrespective of the groups examined. Ethanol treated rats were found to have slightly but significantly fewer pyramidal cell neurons than either the MRC or SC groups. These observations indicate that pyramidal cells in the hippocampus may be vulnerable to a relatively high dose of ethanol exposure during this short period of early postnatal life. (C) 2003 Wiley-Liss, Inc.

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Mating order can have important consequences for the fertilization success of males whose ejaculates compete to fertilize a clutch of eggs. Despite an excellent body of literature on mating-order effects in many animals, they have rarely been considered in marine free-spawning invertebrates, where both sexes release gametes into the water column. In this study, we show that in such organisms, mating order can have profound repercussions for male reproductive success. Using in vitro fertilization for two species of sea urchin we found that the 'fertilization history' of a clutch of eggs strongly influenced the size distribution of unfertilized eggs, and consequently the likelihood that they will be fertilized. Males that had first access to a batch of eggs enjoyed elevated fertilization success because they had privileged access to the largest and therefore most readily fertilizable eggs within a clutch. By contrast, when a male's sperm were exposed to a batch of unfertilized eggs left over from a previous mating event, fertilization rates were reduced, owing to smaller eggs remaining in egg clutches previously exposed to sperm. Because of this size-dependent fertilization, the fertilization history of eggs also strongly influenced the size distribution of offspring, with first-spawning males producing larger, and therefore fitter, offspring. These findings suggest that when there is variation in egg size, mating order will influence not only the quantity but also the quality of offspring sired by competing males.

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We demonstrate complete characterization of a two-qubit entangling process-a linear optics controlled-NOT gate operating with coincident detection-by quantum process tomography. We use a maximum-likelihood estimation to convert the experimental data into a physical process matrix. The process matrix allows an accurate prediction of the operation of the gate for arbitrary input states and a calculation of gate performance measures such as the average gate fidelity, average purity, and entangling capability of our gate, which are 0.90, 0.83, and 0.73, respectively.