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Kinds of Likely Terms modified by Likely Selected AbstractsRAPID EVOLUTIONARY ESCAPE BY LARGE POPULATIONS FROM LOCAL FITNESS PEAKS IS LIKELY IN NATUREEVOLUTION, Issue 6 2005Daniel M. Weinreich Abstract Fitness interactions between loci in the genome, or epistasis, can result in mutations that are individually deleterious but jointly beneficial. Such epistasis gives rise to multiple peaks on the genotypic fitness landscape. The problem of evolutionary escape from such local peaks has been a central problem of evolutionary genetics for at least 75 years. Much attention has focused on models of small populations, in which the sequential fixation of valley genotypes carrying individually deleterious mutations operates most quickly owing to genetic drift. However, valley genotypes can also be subject to mutation while transiently segregating, giving rise to copies of the high fitness escape genotype carrying the jointly beneficial mutations. In the absence of genetic recombination, these mutations may then fix simultaneously. The time for this process declines sharply with increasing population size, and it eventually comes to dominate evolutionary behavior. Here we develop an analytic expression for Ncrit, the critical population size that defines the boundary between these regimes, which shows that both are likely to operate in nature. Frequent recombination may disrupt high-fitness escape genotypes produced in populations larger than Ncrit before they reach fixation, defining a third regime whose rate again slows with increasing population size. We develop a novel expression for this critical recombination rate, which shows that in large populations the simultaneous fixation of mutations that are beneficial only jointly is unlikely to be disrupted by genetic recombination if their map distance is on the order of the size of single genes. Thus, counterintuitively, mass selection alone offers a biologically realistic resolution to the problem of evolutionary escape from local fitness peaks in natural populations. [source] The Probability of Pulmonary Embolism Is a Function of the Diagnoses Considered Most Likely Before TestingACADEMIC EMERGENCY MEDICINE, Issue 4 2006Christopher Kabrhel MD Abstract Objectives: To determine the frequency of pulmonary embolism (PE) diagnosis when different alternative diagnoses were considered most likely before testing, because the relationship between specific alternative diagnoses and the diagnosis of PE has not been explored. Methods: This study was a preplanned secondary analysis of a prospective study of the diagnosis of pulmonary embolism conducted in the emergency department (ED) of an urban university hospital. Physicians were queried as to their most likely pretest diagnosis when they ordered any of the following tests to evaluate possible PE: D-dimer, contrast-enhanced computed tomography of the chest, ventilation,perfusion lung scan, or pulmonary angiogram. To compare the frequency of PE diagnosis across alternative diagnoses, risk ratios, 95% confidence intervals (CI), and p-values using Fisher's exact test were calculated. Results: Six hundred seven patients were enrolled, and 61 had PE. Physicians thought PE was the most likely pretest diagnosis in 162 (26.7%) patients, and 20.4% (95% CI = 14.4% to 27.4%) of these patients had PE. For four alternative diagnoses, PE was diagnosed less frequently than when PE was considered most likely: musculoskeletal pain (2.2%, 95% CI = 0.4% to 6.2%), anxiety (1.7%, 95% CI = 0.0 to 9.2%), asthma or chronic obstructive pulmonary disease (0, 95% CI = 0.0 to 10.9%), and viral syndrome (0, 95% CI = 0.0 to 14.3%). Conclusions: The frequency of PE is related to the most likely pretest alternative diagnosis. PE is diagnosed infrequently when anxiety, asthma or chronic obstructive pulmonary disease, musculoskeletal pain, or viral syndrome is the most likely alternative diagnosis. [source] Simple rules for the coexistence and competitive dominance of plants mediated by mycorrhizal fungiECOLOGY LETTERS, Issue 3 2005James Umbanhowar Abstract Mycorrhizal fungi have been demonstrated to be important in the makeup of plant communities. Likely, their most important role is in altering mineral nutrition of plants, which, in turn, is thought to be among the most important determinants of plant competitive ability. Using mathematical models we examine what role these fungi can play in determining the competitive outcome between two plants in competition for one mineral resource. Depending on different relationships between the benefit accrued to the plant and the fungi, the presence of mycorrhizal fungi can (i) have no impact on which plant wins in competition, (ii) change the order of competitive dominance or (iii) enable coexistence when compared with the system in the absence of mycorrhizal fungi. Furthermore, environmental conditions, such as light and nutrient levels, can determine if coexistence is possible. We describe the necessary biological trade-offs for coexistence and experimental tests for these trade-offs. [source] Imputation aware meta-analysis of genome-wide association studiesGENETIC EPIDEMIOLOGY, Issue 6 2010Noah Zaitlen Abstract Genome-wide association studies have recently identified many new loci associated with human complex diseases. These newly discovered variants typically have weak effects requiring studies with large numbers of individuals to achieve the statistical power necessary to identify them. Likely, there exist even more associated variants, which remain to be found if even larger association studies can be assembled. Meta-analysis provides a straightforward means of increasing study sample sizes without collecting new samples by combining existing data sets. One obstacle to combining studies is that they are often performed on platforms with different marker sets. Current studies overcome this issue by imputing genotypes missing from each of the studies and then performing standard meta-analysis techniques. We show that this approach may result in a loss of power since errors in imputation are not accounted for. We present a new method for performing meta-analysis over imputed single nucleotide polymorphisms, show that it is optimal with respect to power, and discuss practical implementation issues. Through simulation experiments, we show that our imputation aware meta-analysis approach outperforms or matches standard meta-analysis approaches. Genet. Epidemiol. 34: 537,542, 2010. © 2010 Wiley-Liss, Inc. [source] How Likely is Proportional Representation in the House of Commons?GOVERNMENT AND OPPOSITION, Issue 4 2009Lessons from International Experience This article asks what international evidence suggests about the likelihood of major reform of the system used to elect the British House of Commons. It identifies four paths that have generated major electoral reform or come close to doing so in established democracies in recent decades and examines how likely each is to lead to reform in the UK. It argues that, on this evidence, reform in the UK is unlikely but not impossible. [source] Murine TNF,ARE Crohn's disease model displays diminished expression of intestinal Ca2+ transportersINFLAMMATORY BOWEL DISEASES, Issue 6 2008Sylvie Huybers MSc Abstract Background: Patients suffering from Crohn's disease (CD) show increased incidence of low bone mineral density. Investigating this complication is difficult because the exact etiology of CD remains elusive. Mice carrying a deletion in the tumor necrosis factor (TNF) AU-rich elements (ARE) are reported as a model for human CD and are characterized by elevated TNF-, levels and inflammations in the terminal ileum. To evaluate whether these mice have a Ca2+ handling problem, this study analyzed the Ca2+ homeostasis in heterozygous TNF,ARE mice (TNF,ARE/+) in comparison to wildtype littermates. Methods: Beside serum Ca2+ and vitamin D levels, the expression of Ca2+ transporters was analyzed in intestine, kidney and bone using quantitative real-time PCR, Western blot and immunohistochemistry. Bone scans were performed to measure bone parameters. Results: Ca2+ transporters in duodenum (TRPV6, calbindin-D9K, PMCA1b) and kidney (TRPV5, calbindin-D28K, NCX1) showed significantly reduced mRNA expression levels in TNP,ARE/+ mice, except for renal TRPV5. In bone, only calbindin-D9K mRNA displayed a significant down-regulation. These findings were supported by declined duodenal calbindin-D9K and renal calbindin-D28K protein values. Likely, this down-regulation of Ca2+ transporters in TNP,ARE/+ mice is mediated by the 58 ± 9% reduction in serum 1,25(OH)2D3 levels. Diminished expression of Ca2+ transporters combined with unchanged serum Ca2+ levels assumes Ca2+ loss from bone to compensate for the body's overall Ca2+ shortage. Indeed, microcomputed tomography scanning demonstrated reduced trabecular and corticol bone thickness and volume in TNF,ARE/+ mice. This finding is further supported by increased total deoxypyridinoline in serum. Conclusions: Our results imply that TNF,ARE/+ mice have a disturbed Ca2+ homeostasis characterized by reduced duodenal and renal Ca2+ transporters, diminished 1,25(OH)2D3 levels, and increased bone resorption associated with profound bone abnormalities. (Inflamm Bowel Dis 2008) [source] Colonic sarcoidosis, infliximab, and tuberculosis: A cautionary taleINFLAMMATORY BOWEL DISEASES, Issue 4 2004Prof. Dario Sorrentino MD Abstract The antitumor necrosis factor, infliximab, has been recently shown to be effective in refractory sarcoidosis including the intestinal form of this disease. We have tried this therapy in a 55-year-old woman under immunosuppressive therapy for longstanding sarcoidosis presenting with abdominal pain apparently caused by a colonic localization of the disease. The latter diagnosis was based, as recommended, on the presence of nonnecrotizing granulomas in mucosal biopsies, the presence of systemic disease, and the careful exclusion of other granulomatous diseases, including tuberculosis. After the first IV infusion (10 mg/kg BW), she quickly improved, but the wellbeing lasted approximately 4 weeks. She then received another dose of infliximab, but she soon developed low-grade fever and weakness and shortly succumbed of miliary tuberculosis. Likely, infliximab precipitated a pre-existing mycobacterial infection of the intestine. Given the likelihood of underdiagnosing intestinal tuberculosis,and the risks associated with infliximab treatment,this case suggests that this drug should be used with extreme caution, if at all, when a diagnosis of colonic sarcoidosis is suspected. [source] Why Fiscal Stimulus is Likely to WorkINTERNATIONAL FINANCE, Issue 1 2009Antonio Fatás We provide an overview of the effectiveness of fiscal policy actions by summarizing evidence from empirical and theoretical studies. Empirically, expansionary policy is found to have output multipliers greater than one. Given current economic conditions, we argue that the fiscal cost of not stabilizing the economy is likely to be much higher than the cost of a deficit that helps the economy go faster towards a recovery path. [source] Cannabis: What Makes University Students More or Less Likely to Use It?JOURNAL OF APPLIED BIOBEHAVIORAL RESEARCH, Issue 2 2006Frances V. O'Callaghan University students' motivations for using or not using cannabis were investigated. Students (n = 189) aged 17 to 29 years completed a survey to assess their intention to use cannabis and their beliefs about (a) advantages and disadvantages of using cannabis; (b) their perceptions of what significant others think they should do in relation to cannabis use; and (c) factors that might encourage them to use or not use cannabis. Two weeks later, they completed a follow-up survey asking about their actual behavior over the previous 2 weeks. Compared to non-users, users believed more strongly that cannabis would help them fit in with their friends, feel relaxed, forget their worries, and enjoy themselves. They also believed that their close friends, partner/spouse, siblings, and workmates would approve of their using cannabis. Users believed that certain factors (e.g., force of habit, wanting to relax, feeling stressed, being around other people using cannabis) would encourage them to use, while non-users rated work and study as strong reasons for not using cannabis. Beliefs that are relevant to users and non-users in education campaigns can be targeted to reduce the negative consequences of use in tertiary settings. [source] Probiotic and Prebiotic Influence Beyond the Intestinal TractNUTRITION REVIEWS, Issue 11 2007Irene Lenoir-Wijnkoop Probiotics and prebiotics have long been appreciated for their positive influences on gut health. Research on the mechanisms and effects of these agents shows that their impact reaches beyond the intestine. Effects on the microecology and pathology of the oral cavity, stomach, and vaginal tract have been observed. Likely mediated through immune influences, systemic effects such as reduced severity of colds or other respiratory conditions, impact on allergy incidence and symptoms, and reduced absences from work or daycare have also been noted. These observations, among others, suggest a broader spectrum of influence than commonly considered for these unique substances. [source] Bargaining in the Shadow of War: When Is a Peaceful Resolution Most Likely?AMERICAN JOURNAL OF POLITICAL SCIENCE, Issue 3 2009Donald Wittman This article derives the optimal bargaining strategies of the belligerents when each side has private but incomplete information about the expected outcome of a war, should it take place. I show that the aggressor's demand curve can be below the defender's offer curve, that wars are possible even when both sides are jointly pessimistic, and that the relative cost of a war can radically alter the types of disputes that end in war. A simple diagram provides the intuition for most of the major propositions. [source] The Importance of Emergency Medicine in Organ Donation: Successful Donation Is More Likely When Potential Donors Are Referred From the Emergency DepartmentACADEMIC EMERGENCY MEDICINE, Issue 9 2009Glen E. Michael MD Abstract Objectives:, This study sought to identify factors that are associated with successful organ retrieval among patients referred to organ procurement services for potential organ donation. Particular attention was paid to the frequency, patient characteristics, and outcomes of patients referred for donation from the emergency department (ED). Methods:, For this retrospective cohort study, data were collected on all solid-organ donor referrals made to a single organ procurement organization serving 78 hospitals over a 45-month period. Data retrieved included patient age, sex, race, referral site (ED vs. inpatient), and mechanism of injury. Outcome of referral (organs retrieved or not) was the primary outcome variable. Pearson chi-square and Student's t-tests were used for bivariate statistical analysis. Multiple logistic regression analysis was used to determine which variables remained associated with organ retrieval after controlling for potential confounders. Results:, A total of 6,886 donor referrals were made in the study population. Of these, 155 were excluded due to incomplete data, leaving 6,731 subjects for analysis. Using bivariate statistical analysis, we found that successful organ retrieval was associated with younger age (donor mean age 40.8 years, 95% confidence interval [CI] = 39.1 to 42.5 vs. nondonor mean age 59.4, 95% CI = 58.9 to 59.9), mechanism of injury (p < 0.001), and referral from the ED (ED 15.5% retrieved, inpatient 5.9%, odds ratio [OR] = 2.92, 95% CI = 2.32 to 3.67). After controlling for potential confounders with multiple logistic regression, referral from the ED remained significantly associated with successful organ retrieval (OR = 1.52, 95% CI = 1.18 to 1.97), as did age (OR = 0.96, 95% CI = 0.96 to 0.97) and mechanism of injury (p < 0.001). On regression analysis, race emerged as a significant predictor of organ retrieval (p < 0.001). Medically suitable patients referred from the ED were significantly more likely on bivariate analysis to have consent for donation granted compared to patients referred from inpatient settings (OR = 1.48, 95% CI = 1.03 to 2.12), but this association was not found to be significant on regression analysis (OR = 1.37, 95% CI = 0.93 to 2.02). Conclusions:, Referral of potential organ donors from the ED is associated with an increased likelihood of successful organ retrieval. The authors conclude that further attention and resources should be directed toward the role of emergency medicine (EM) in the organ procurement process, owing to the relatively high likelihood of successful organ retrieval among patients referred from the ED. [source] Large Allele Frequency Differences between Human Continental Groups are more Likely to have Occurred by Drift During range Expansions than by SelectionANNALS OF HUMAN GENETICS, Issue 1 2009T. Hofer Summary Several studies have found strikingly different allele frequencies between continents. This has been mainly interpreted as being due to local adaptation. However, demographic factors can generate similar patterns. Namely, allelic surfing during a population range expansion may increase the frequency of alleles in newly colonised areas. In this study, we examined 772 STRs, 210 diallelic indels, and 2834 SNPs typed in 53 human populations worldwide under the HGDP-CEPH Diversity Panel to determine to which extent allele frequency differs among four regions (Africa, Eurasia, East Asia, and America). We find that large allele frequency differences between continents are surprisingly common, and that Africa and America show the largest number of loci with extreme frequency differences. Moreover, more STR alleles have increased rather than decreased in frequency outside Africa, as expected under allelic surfing. Finally, there is no relationship between the extent of allele frequency differences and proximity to genes, as would be expected under selection. We therefore conclude that most of the observed large allele frequency differences between continents result from demography rather than from positive selection. [source] Medicare Managed Care Patients More Likely to Use HospiceCA: A CANCER JOURNAL FOR CLINICIANS, Issue 4 2003Article first published online: 31 DEC 200 No abstract is available for this article. [source] Emergency Medicine Practitioner Knowledge and Use of Decision Rules for the Evaluation of Patients with Suspected Pulmonary Embolism: Variations by Practice Setting and Training LevelACADEMIC EMERGENCY MEDICINE, Issue 1 2007Michael S. Runyon MD Abstract Background Several clinical decision rules (CDRs) have been validated for pretest probability assessment of pulmonary embolism (PE), but the authors are unaware of any data quantifying and characterizing their use in emergency departments. Objectives To characterize clinicians' knowledge of and attitudes toward two commonly used CDRs for PE. Methods By using a modified Delphi approach, the authors developed a two-page paper survey including 15 multiple-choice questions. The questions were designed to determine the respondents' familiarity, frequency of use, and comprehension of the Canadian and Charlotte rules. The survey also queried the frequency of use of unstructured (gestalt) pretest probability assessment and reasons why physicians choose not to use decision rules. The surveys were sent to physicians, physician assistants, and medical students at 32 academic and community hospitals in the United States and the United Kingdom. Results Respondents included 555 clinicians; 443 (80%) work in academic practice, and 112 (20%) are community based. Significantly more academic practitioners (73%) than community practitioners (49%) indicated familiarity with at least one of the two decision rules. Among all respondents familiar with a rule, 50% reported using it in more than half of applicable cases. A significant number of these respondents could not correctly identify a key component of the rule (23% for the Charlotte rule and 43% for the Canadian rule). Fifty-seven percent of all respondents indicated use of gestalt rather than a decision rule in more than half of cases. Conclusions Academic clinicians were more likely to report familiarity with either of these two specific decision rules. Only one half of all clinicians reporting familiarity with the rules use them in more than 50% of applicable cases. Spontaneous recall of the specific elements of the rules was low to moderate. Future work should consider clinical gestalt in the evaluation of patients with possible PE. [source] Maternal employment and the initiation of breastfeedingACTA PAEDIATRICA, Issue 4 2001S Noble This study examines whether planning to be employed postpartum has an effect on initiation of breastfeeding. Data were collected from questionnaires completed by mothers who were subjects in the prospective, population-based, Avon Longitudinal Study of Pregnancy and Childhood. The mothers of 10 530 full-term singleton infants gave information during pregnancy on their postpartum employment plans and their initial infant feeding methods. Information was also given by 7642 of these mothers on the timing of their postpartum employment plans. Adjusted logistic regression was performed to identify associations between (a) "any" plans to work postpartum and the initiation of breastfeeding, and (b) the timing of the commencement of work postpartum, and the initiation of breastfeeding. A total of 8316 (79%) of the women initiated breastfeeding. The decision to breastfeed was not associated with "any" plans to work postpartum. However, women who planned to commence work prior to 6 wk postpartum were significantly less likely to initiate breastfeeding compared with those not intending to work postpartum. Older, more highly educated women, women who had or were planning to attend childbirth classes, women who were breastfed as infants, women who did not smoke and women who were giving birth to their first child were significantly more likely to initiate breastfeeding. Conclusion: Planning to return to employment prior to 6 wk postpartum reduces the likelihood of initiating breastfeeding. As increasing numbers of mothers are returning to work shortly after the birth of their child, this finding could have implications for maintaining the current level of breastfeeding. [source] A Bayesian Monte Carlo Approach to Global IlluminationCOMPUTER GRAPHICS FORUM, Issue 8 2009Jonathan Brouillat I.3.7 [Computer Graphics]: Three-Dimensional Graphics an Realism Abstract Most Monte Carlo rendering algorithms rely on importance sampling to reduce the variance of estimates. Importance sampling is efficient when the proposal sample distribution is well-suited to the form of the integrand but fails otherwise. The main reason is that the sample location information is not exploited. All sample values are given the same importance regardless of their proximity to one another. Two samples falling in a similar location will have equal importance whereas they are likely to contain redundant information. The Bayesian approach we propose in this paper uses both the location and value of the data to infer an integral value based on a prior probabilistic model of the integrand. The Bayesian estimate depends only on the sample values and locations, and not how these samples have been chosen. We show how this theory can be applied to the final gathering problem and present results that clearly demonstrate the benefits of Bayesian Monte Carlo. [source] Recurrence of kernicterus in term and near-term infants in DenmarkACTA PAEDIATRICA, Issue 10 2000F Ebbesen Classical acute bilirubin encephalopathy (kernicterus) in term and near-term infants had not been seen in Denmark for at least 20 y until 1994. From 1994 to 1998, however, six cases were diagnosed. Aetiology of the hyperbilirubinaemia was known in two infants; spherocytosis and galactosaemia, most likely known in two infants; possible A-O blood type immunization, and unknown in two infants. However, one of these last-mentioned infants had a gestational age of only 36 wk. The maximum plasma total bilirubin concentrations were 531,745 ,mol/L. The increase in the number of cases of kernicterus was considered to have been caused by: (i) a decreased awareness of the pathological signs, (ii) a change in the assessment of the risk of bilirubin encephalopathy, (iii) early discharge of the infants from the maternity ward, (iv) so-called breastfeeding-associated jaundice, (v) demonstration of bilirubin being an antioxidant, and (vi) difficulty in estimating the degree of jaundice in certain groups of immigrants. Accordingly, for prevention: (a) Attempt to change the healthcare workers' understanding of the risk of bilirubin encephalopathy, (b) give further instructions, both orally and in writing, to mothers before discharge from the maternity ward, (c) be more liberal in giving infant formula supplements, (d) conduct home visits by the community nurse at an earlier stage, (e) follow authorized guidelines for phototherapy and exchange transfusion, (f) lower plasma bilirubin concentration limits as an indication for phototherapy and exchange transfusion, (g) screen all term and near-term infants, and (h) measure the skin's yellow colour with a device that corrects for the skin's melanin content. Conclusions: Audit of the six cases presented indicates that measures are necessary in both the primary and secondary healthcare sectors if the risk of kernicterus is to be avoided. Screening may be considered, but in order to identify the problems it would first be reasonable to perform a larger prospective study in which audit is performed on all newborn infants, born at term and near-term, who develop a plasma bilirubin concentration above the exchange transfusion limit. [source] Priority-Driven Acoustic Modeling for Virtual EnvironmentsCOMPUTER GRAPHICS FORUM, Issue 3 2000Patrick Min Geometric acoustic modeling systems spatialize sounds according to reverberation paths from a sound source to a receiver to give an auditory impression of a virtual 3D environment. These systems are useful for concert hall design, teleconferencing, training and simulation, and interactive virtual environments. In many cases, such as in an interactive walkthrough program, the reverberation paths must be updated within strict timing constraints - e.g., as the sound receiver moves under interactive control by a user. In this paper, we describe a geometric acoustic modeling algorithm that uses a priority queue to trace polyhedral beams representing reverberation paths in best-first order up to some termination criteria (e.g., expired time-slice). The advantage of this algorithm is that it is more likely to find the highest priority reverberation paths within a fixed time-slice, avoiding many geometric computations for lower-priority beams. Yet, there is overhead in computing priorities and managing the priority queue. The focus of this paper is to study the trade-offs of the priority-driven beam tracing algorithm with different priority functions. During experiments computing reverberation paths between a source and a receiver in a 3D building environment, we find that priority functions incorporating more accurate estimates of source-to-receiver path length are more likely to find early reverberation paths useful for spatialization, especially in situations where the source and receiver cannot reach each other through trivial reverberation paths. However, when receivers are added to the environment such that it becomes more densely and evenly populated, this advantage diminishes. [source] Sexual abuse at a Swedish daycare centre: allegations, confessions and evaluationsACTA PAEDIATRICA, Issue 8 2000F Lindblad In September 1997, sexual abuse at a Swedish daycare centre was disclosed. The suspect, a male member of the staff, admitted having abused six children. A total of 30 children were included in the police investigation. In this study, these cases were evaluated individually using a child psychiatric method. Information was collected from the police investigation and from interviews with parents. The conclusions,categorized as "abuse likely", "abuse conceivable" or "abuse uncertain",were compared with the children's own reports, the legal evaluations and the confessions of the suspects. Conclusions: The correspondence of child reports with child psychiatric evaluations was fairly high, indicating that child reports may serve as a good screening indicator of abuse. There was little agreement between child psychiatric evaluations and legal decisions, which were based on the reports of suspects. Some differences may be explained by varied methodology, definitions and criteria. Others reflect real differences in opinion. Our study illustrates the need to establish legal criteria for statements from pre-schoolers if such evidence is to constitute the basis of a ruling without a confession. Studies comparing professional psychological assessments of children's statements about sexual abuse with independent data stand out as an important line of research for the future. [source] Investigating Driver Injury Severity in Traffic Accidents Using Fuzzy ARTMAPCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 6 2002Hassan T. Abdelwahab This paper applies fuzzy adaptive resonance theory MAP (fuzzy ARTMAP) neural networks to analyze and predict injury severity for drivers involved in traffic accidents. The paper presents a modified version of fuzzy ARTMAP in which the training patterns are ordered using the K,means algorithm before being presented to the neural network. The paper presents three applications of fuzzy ARTMAP for analyzing driver injury severity for drivers involved in accidents on highways, signalized intersections, and toll plazas. The analysis is based on central Florida's traffic accident database. Results showed that the ordered fuzzy ARTMAP proved to reduce the network size and improved the performance. To facilitate the application of fuzzy ARTMAP, a series of simulation experiments to extract knowledge from the models were suggested. Results of the fuzzy ARTMAP neural network showed that female drivers experience higher severity levels than male drivers. Vehicle speed at the time of an accident increases the likelihood of high injury severity. Wearing a seat belt decreases the chance of having severe injuries. Drivers in passenger cars are more likely to experience a higher injury severity level than those in vans or pickup trucks. Point of impact, area type, driving under the influence, and driver age were also among the factors that influence the severity level. [source] Trust-based robust scheduling and runtime adaptation of scientific workflowCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 16 2009Mingzhong Wang Abstract Robustness and reliability with respect to the successful completion of a schedule are crucial requirements for scheduling in scientific workflow management systems because service providers are becoming autonomous. We introduce a model to incorporate trust, which indicates the probability that a service agent will comply with its commitments to improve the predictability and stability of the schedule. To deal with exceptions during the execution of a schedule, we adapt and evolve the schedule at runtime by interleaving the processes of evaluating, scheduling, executing and monitoring in the life cycle of the workflow management. Experiments show that schedules maximizing participants' trust are more likely to survive and succeed in open and dynamic environments. The results also prove that the proposed approach of workflow evaluation can find the most robust execution flow efficiently, thus avoiding the need of scheduling every possible execution path in the workflow definition. Copyright © 2009 John Wiley & Sons, Ltd. [source] An evidence-based iterative content trust algorithm for the credibility of online newsCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 15 2009Guosun Zeng Abstract People encounter more information than they can possibly use every day. But all information is not necessarily of equal value. In many cases, certain information appears to be better, or more trustworthy, than other information. And the challenge that most people then face is to judge which information is more credible. In this paper we propose a new problem called Corroboration Trust, which studies how to find credible news events by seeking more than one source to verify information on a given topic. We design an evidence-based corroboration trust algorithm called TrustNewsFinder, which utilizes the relationships between news articles and related evidence information (person, location, time and keywords about the news). A news article is trustworthy if it provides many pieces of trustworthy evidence, and a piece of evidence is likely to be true if it is provided by many trustworthy news articles. Our experiments show that TrustNewsFinder successfully finds true events among conflicting information and identifies trustworthy news better than the popular search engines. Copyright © 2009 John Wiley & Sons, Ltd. [source] A dynamic admission control scheme to manage contention on shared computing resourcesCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 2 2009Percival Xavier Abstract A virtual organization is established when physical organizations collaborate to share their computing resources with the aim of serving each other when there is a likelihood of insufficient local resources during peak resource usage periods at any organization. Contention becomes a potential problem when a large number of requests, which can overwhelm the aggregate capacity of shared resources, are submitted from the participating organizations coincidentally at the same period. In particular, when a small number of requests that require large amounts of computing resources are admitted in place of a large number of requests that require less computing resources, the overall system performance, in terms of admission ratio, can deteriorate significantly. Hence, admission control is necessary to reduce resource oversubscription. Because domain-shared computing resources are likely to be combined to form a large-scale system, it is not possible to define a fixed admission policy solely based on the request's CPU and execution time requirements. In this paper, we introduce an admission control framework, based on a pricing model, for a multi-domain-shared computing infrastructure. The performance of the admission control framework is evaluated under different scenarios that contribute to the overall degree of competition for shared resources. The results are presented and analyzed in this paper. Copyright © 2008 John Wiley & Sons, Ltd. [source] A new task scheduling method for distributed programs that require memory managementCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 9 2006Hiroshi Koide Abstract In parallel and distributed applications, it is very likely that object-oriented languages, such as Java and Ruby, and large-scale semistructured data written in XML will be employed. However, because of their inherent dynamic memory management, parallel and distributed applications must sometimes suspend the execution of all tasks running on the processors. This adversely affects their execution on the parallel and distributed platform. In this paper, we propose a new task scheduling method called CP/MM (Critical Path/Memory Management) which can efficiently schedule tasks for applications requiring memory management. The underlying concept is to consider the cost due to memory management when the task scheduling system allocates ready (executable) coarse-grain tasks, or macro-tasks, to processors. We have developed three task scheduling modules, including CP/MM, for a task scheduling system which is implemented on a Java RMI (Remote Method Invocation) communication infrastructure. Our experimental results show that CP/MM can successfully prevent high-priority macro-tasks from being affected by the garbage collection arising from memory management, so that CP/MM can efficiently schedule distributed programs whose critical paths are relatively long. Copyright © 2005 John Wiley & Sons, Ltd. [source] Simple verification technique for complex Java bytecode subroutinesCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 7 2004Alessandro Coglio Abstract Java is normally compiled to bytecode, which is verified and then executed by the Java Virtual Machine. Bytecode produced via compilation must pass verification. The main cause of complexity for bytecode verification is subroutines, used by compilers to generate more compact code. The techniques to verify subroutines proposed in the literature reject certain programs produced by mundane compilers, are difficult to realize within an implementation of the Java Virtual Machine or are relatively complicated. This paper presents a novel technique which is very simple to understand, implement and prove sound. It is also very powerful: the set of accepted programs has a simple characterization which most likely includes all the code produced by current compilers and which enables future compilers to make more extensive use of subroutines. Copyright © 2004 John Wiley & Sons, Ltd. [source] Deep Start: a hybrid strategy for automated performance problem searchesCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 11-12 2003Philip C. Roth Abstract To attack the problem of scalability of performance diagnosis tools with respect to application code size, we have developed the Deep Start search strategy,a new technique that uses stack sampling to augment an automated search for application performance problems. Our hybrid approach locates performance problems more quickly and finds performance problems hidden from a more straightforward search strategy. The Deep Start strategy uses stack samples collected as a by-product of normal search instrumentation to select deep starters, functions that are likely to be application bottlenecks. With priorities and careful control of the search refinement, our strategy gives preference to experiments on the deep starters and their callees. This approach enables the Deep Start strategy to find application bottlenecks more efficiently and more effectively than a more straightforward search strategy. We implemented the Deep Start search strategy in the Performance Consultant, Paradyn's automated bottleneck detection component. In our tests, Deep Start found half of our test applications' known bottlenecks between 32% and 59% faster than the Performance Consultant's current search strategy, and finished finding bottlenecks between 10% and 61% faster. In addition to improving the search time, Deep Start often found more bottlenecks than the call graph search strategy. Copyright © 2003 John Wiley & Sons, Ltd. [source] Nitric oxide bioavailability modulates the dynamics of microvascular oxygen exchange during recovery from contractionsACTA PHYSIOLOGICA, Issue 2 2010D. M. Hirai Abstract Aim:, Lowered microvascular PO2 (PO2mv) during the exercise off-transient likely impairs muscle metabolic recovery and limits the capacity to perform repetitive tasks. The current investigation explored the impact of altered nitric oxide (NO) bioavailability on PO2mv during recovery from contractions in healthy skeletal muscle. We hypothesized that increased NO bioavailability (sodium nitroprusside: SNP) would enhance PO2mv and speed its recovery kinetics while decreased NO bioavailability (l -nitro arginine methyl ester: l -NAME) would reduce PO2mv and slow its recovery kinetics. Methods:,PO2mv was measured by phosphorescence quenching during transitions (rest,1 Hz twitch-contractions for 3 min,recovery) in the spinotrapezius muscle of Sprague,Dawley rats under SNP (300 ,m), Krebs-Henseleit (Control) and l -NAME (1.5 mm) superfusion conditions. Results:, Relative to recovery in Control, SNP resulted in greater overall microvascular oxygenation as assessed by the area under the PO2mv curve (PO2 AREA; Control: 3471 ± 292 mmHg s; SNP: 4307 ± 282 mmHg s; P < 0.05) and faster off-kinetics as evidenced by the mean response time (MRToff; Control: 60.2 ± 6.9 s; SNP: 34.8 ± 5.7 s; P < 0.05), whereas l -NAME produced lower PO2 AREA (2339 ± 444 mmHg s; P < 0.05) and slower MRToff (86.6 ± 14.5 s; P < 0.05). Conclusion:, NO bioavailability plays a key role in determining the matching of O2 delivery-to-O2 uptake and thus the upstream O2 pressure driving capillary-myocyte O2 flux (i.e. PO2mv) following cessation of contractions in healthy skeletal muscle. Additionally, these data support a mechanistic link between reduced NO bioavailability and prolonged muscle metabolic recovery commonly observed in ageing and diseased populations. [source] Patterns of chromosomal deletions identified by a birth defects registry, Hawaii, 1986,2003CONGENITAL ANOMALIES, Issue 2 2007Mathias B. Forrester ABSTRACT The aim of the investigation was to describe the chromosomal deletions identified by a birth defects registry with respect to the chromosomes involved, pregnancy outcome, method of diagnosis, inheritance, sex, and the diagnosis of major structural birth defects. Cases were derived from a population-based birth defects registry in Hawaii and comprised all infants and fetuses with chromosomal deletions delivered during 1986,2003. A total of 71 cases were identified through a statewide birth defects registry in Hawaii during 1986,2003. The chromosomes involved in the greatest proportion of deletions were chromosomes 22 (14.1%), 4 (11.3%), and 5 (11.3%). Live births accounted for 58 (81.7%) of the cases. Diagnosis was made by amniocentesis or chorionic villus sampling in 19 (26.8%) of the cases. Of the 18 cases with known inheritance, the deletion was inherited in 5 (27.8%) and de novo in 13 (72.2%). Males accounted for 28 (39.4%) and females for 43 (60.6%) of the cases. Major structural birth defects were identified in 51 (71.8%) of the cases. Chromosomal deletions do not appear to affect all chromosomes equally. Most of the chromosomal deletions that were detected occurred among live births and were de novo conditions. Infants and fetuses with chromosomal deletions are more likely to be females and to be associated with major structural birth defects. [source] Cardiovascular function in the heat-stressed humanACTA PHYSIOLOGICA, Issue 4 2010C. G. Crandall Abstract Heat stress, whether passive (i.e. exposure to elevated environmental temperatures) or via exercise, results in pronounced cardiovascular adjustments that are necessary for adequate temperature regulation as well as perfusion of the exercising muscle, heart and brain. The available data suggest that generally during passive heat stress baroreflex control of heart rate and sympathetic nerve activity are unchanged, while baroreflex control of systemic vascular resistance may be impaired perhaps due to attenuated vasoconstrictor responsiveness of the cutaneous circulation. Heat stress improves left ventricular systolic function, evidenced by increased cardiac contractility, thereby maintaining stroke volume despite large reductions in ventricular filling pressures. Heat stress-induced reductions in cerebral perfusion likely contribute to the recognized effect of this thermal condition in reducing orthostatic tolerance, although the mechanism(s) by which this occurs is not completely understood. The combination of intense whole-body exercise and environmental heat stress or dehydration-induced hyperthermia results in significant cardiovascular strain prior to exhaustion, which is characterized by reductions in cardiac output, stroke volume, arterial pressure and blood flow to the brain, skin and exercising muscle. These alterations in cardiovascular function and regulation late in heat stress/dehydration exercise might involve the interplay of both local and central reflexes, the contribution of which is presently unresolved. [source] | |||||||||||||||||||||||||||||||