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Chance Alone (chance + alone)
Selected AbstractsComparison of the Medical Priority Dispatch System to an Out-of-hospital Patient Acuity ScoreACADEMIC EMERGENCY MEDICINE, Issue 9 2006Michael J. Feldman MD Abstract Background: Although the Medical Priority Dispatch System (MPDS) is widely used by emergency medical services (EMS) dispatchers to determine dispatch priority, there is little evidence that it reflects patient acuity. The Canadian Triage and Acuity Scale (CTAS) is a standard patient acuity scale widely used by Canadian emergency departments and EMS systems to prioritize patient care requirements. Objectives: To determine the relationship between MPDS dispatch priority and out-of-hospital CTAS. Methods: All emergency calls on a large urban EMS communications database for a one-year period were obtained. Duplicate calls, nonemergency transfers, and canceled calls were excluded. Sensitivity and specificity to detect high-acuity illness, as well as positive predictive value (PPV) and negative predictive value (NPV), were calculated for all protocols. Results: Of 197,882 calls, 102,582 met inclusion criteria. The overall sensitivity of MPDS was 68.2% (95% confidence interval [CI] = 67.8% to 68.5%), with a specificity of 66.2% (95% CI = 65.7% to 66.7%). The most sensitive protocol for detecting high acuity of illness was the breathing-problem protocol, with a sensitivity of 100.0% (95% CI = 99.9% to 100.0%), whereas the most specific protocol was the one for psychiatric problems, with a specificity of 98.1% (95% CI = 97.5% to 98.7%). The cardiac-arrest protocol had the highest PPV (92.6%, 95% CI = 90.3% to 94.3%), whereas the convulsions protocol had the highest NPV (85.9%, 95% CI = 84.5% to 87.2%). The best-performing protocol overall was the cardiac-arrest protocol, and the protocol with the overall poorest performance was the one for unknown problems. Sixteen of the 32 protocols performed no better than chance alone at identifying high-acuity patients. Conclusions: The Medical Priority Dispatch System exhibits at least moderate sensitivity and specificity for detecting high acuity of illness or injury. This performance analysis may be used to identify target protocols for future improvements. [source] Clustering of cardiovascular risk factors with diabetes in Chinese patients: the effects of sex and hyperinsulinaemiaDIABETES OBESITY & METABOLISM, Issue 3 2001Z. -R. SUMMARY Objective This study was designed to investigate factors which affect the clustering of cardiovascular risk factors with diabetes in Chinese patients. Research Design and Methods: Six hundred and fifty-four patients with diabetes were assessed comprehensively for diabetes complications and cardiovascular risk factors in a metropolitan hospital in Beijing, China. Insulin resistance and secretion were also evaluated by measurement of glucose and insulin levels before and after a meal tolerance test. Results were analysed according to patient groups stratified by the number of cardiovascular risk factors coexisting with diabetes. Results Cardiovascular risk factors were common in Chinese diabetic patients. The clustering of three or more of these factors with diabetes occurred more often than by chance alone and was associated with postprandial hyperinsulinaemia. Patients with a high number of risk factors were more prone to macrovascular events but did not have higher albuminuria. Using the commonly adopted lower threshold for diagnosing obesity and central obesity in women, there were more women with multiple risk factors. However, this disappeared if the same criteria were used for men and women. Even in the presence of diabetes, cardiovascular risk factors were inadequately controlled in most patients. Conclusions The concurrence of diabetes and other cardiovascular risk factors which constitute the metabolic syndrome is a common phenomenon in urban Chinese diabetic patients. It is associated with hyperinsulinaemia and possibly the female sex. This study emphasises the importance of public health measures to control cardiovascular risk factors in patients with diabetes. [source] Community structure of arboreal caterpillars within and among four tree species of the eastern deciduous forestECOLOGICAL ENTOMOLOGY, Issue 6 2003Keith S. Summerville Abstract., 1.,A seasonally replicated experimental design was used to address the question of how differences within and among host tree species affect arboreal caterpillar communities. 2.,Seasonal variation influenced caterpillar community composition most significantly, and the similarity among caterpillar assemblages did not necessarily follow the pattern of phylogenetic relatedness among host trees. 3.,Species richness and abundance of caterpillars were higher on oaks and maples than on American beech. Diversity partitioning models revealed that , diversity was only occasionally greater or less than expected by chance alone. 4.,When , diversity was significant, values tended to be greater than expected by chance among replicate trees within each species and lower than expected by chance among the four tree species. 5.,Differences among trees appeared important for determining patterns of species presence/absence for rare species and influencing patterns of species dominance within caterpillar assemblages. Differences among tree species had a significant effect on overall lepidopteran community composition and mean species diversity (i.e. , diversity). 6.,Because , diversity of caterpillars among host trees was lower than expected by chance, host specificity within the Lepidoptera may be less prevalent than thought previously. [source] LINEAGES WITH LONG DURATIONS ARE OLD AND MORPHOLOGICALLY AVERAGE: AN ANALYSIS USING MULTIPLE DATASETSEVOLUTION, Issue 4 2007Lee Hsiang Liow Lineage persistence is as central to biology as evolutionary change. Important questions regarding persistence include: why do some lineages outlive their relatives, neither becoming extinct nor evolving into separate lineages? Do these long-duration lineages have distinctive ecological or morphological traits that correlate with their geologic durations and potentially aid their survival? In this paper, I test the hypothesis that lineages (species and higher taxa) with longer geologic durations have morphologies that are more average than expected by chance alone. I evaluate this hypothesis for both individual lineages with longer durations and groups of lineages with longer durations, using more than 60 published datasets of animals with adequate fossil records. Analyses presented here show that groups of lineages with longer durations fall empirically into one of three theoretically possible scenarios, namely: (1) the morphology of groups of longer duration lineages is closer to the grand average of their inclusive group, that is, their relative morphological distance is smaller than expected by chance alone, when compared with rarified samples of their shorter duration relatives (a negative group morpho-duration distribution); (2) the relative morphological distance of groups of longer duration lineages is no different from rarified samples of their shorter duration relatives (a null group morpho-duration distribution); and (3) the relative morphological distance of groups of longer duration lineages is greater than expected when compared with rarified samples of their shorter duration relatives (a positive group morpho-duration distribution). Datasets exhibiting negative group morpho-duration distributions predominate. However, lineages with higher ranks in the Linnean hierarchy demonstrate positive morpho-duration distributions more frequently. The relative morphological distance of individual longer duration lineages is no different from that of rarified samples of their shorter duration relatives (a null individual morpho-duration distribution) for the majority of datasets studied. Contrary to the common idea that very persistent lineages are special or unique in some significant way, both the results from analyses of long-duration lineages as groups and individuals show that they are morphologically average. Persistent lineages often arise early in a group's history, even though there is no prior expectation for this tendency in datasets of extinct groups. The implications of these results for diversification histories and niche preemption are discussed. [source] The importance of steatosis in chronic hepatitis C infection and its management: A reviewHEPATOLOGY RESEARCH, Issue 3 2010Timothy J. S. Cross Hepatitis C virus (HCV) infection is a major cause of chronic liver disease with approximately 180 million people infected worldwide. Hepatic steatosis is a frequent histological finding in chronic hepatitis C (CHC) infection and is 2- to 3-fold more common than would be expected by chance alone. A high body mass index with excess visceral fat distribution is associated with steatosis in patients infected with HCV genotype 1 but not genotype 3, re-enforcing the concept that in patients with CHC, some have "metabolic steatosis", predominantly HCV genotype 1, and others "viral steatosis", mainly HCV genotype 3. Accumulating evidence suggests that steatosis may contribute to progression of fibrosis in CHC. Hepatic insulin resistance appears to play a role through the pro-fibrogenic effects of compensatory hyperinsulinemia. The aim of this review was to assess the effect host and viral factors play in steatosis development in patients with CHC infection and its possible relationship with hepatocellular carcinoma. The review examines the mechanisms by which CHC infection causes hepatic steatosis, the impact hepatic steatosis has on the natural history of the disease and finally, explores if treatments leading to a reduction in the amount of steatosis might lead to improved treatment outcomes. The basic medical science of steatosis in CHC will be discussed including proposed models of steatogenesis and the influence of viral and metabolic factors at the molecular level and how these might impact on current and future therapies. [source] Spurious correlations between recent warming and indices of local economic activity,INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 14 2009Gavin A. Schmidt Abstract A series of climate model simulations of the 20th Century are analysed to investigate a number of published correlations between indices of local economic activity and recent global warming. These correlations have been used to support a hypothesis that the observed surface warming record has been contaminated in some way and thus overestimates true global warming. However, the basis of the results are correlations over a very restricted set of locations (predominantly western Europe, Japan and the USA) which project strongly onto naturally occurring patterns of climate variability, or are with fields with significant amounts of spatial auto-correlation. Across model simulations, the correlations vary widely due to the chaotic weather component in any short-term record. The reported correlations do not fall outside the simulated distribution, and are probably spurious (i.e. are likely to have arisen from chance alone). Thus, though this study cannot prove that the global temperature record is unbiased, there is no compelling evidence from these correlations of any large-scale contamination. Copyright © 2009 Royal Meteorological Society [source] The Elements of Rationality and Chance in the Choice of Human ActionJOURNAL FOR THE THEORY OF SOCIAL BEHAVIOUR, Issue 4 2004ERNEST KRAUSZ The focus in this paper is on deliberate human action. The central questions addressed are: whether purely rational choice is possible; whether choices may be induced by chance alone; or whether there is always a mixture of rationality and chance, as well as other factors such as habit, emotion, imitation and irrationality. The approach is a factualist one, upholding the view that, although human action can be explained by its antecedents, this is not incompatible with the notion of "free choice". It is the actual choosing process that determines the final choice of action. Whatever the sources of the elements involved in the choosing process, the choice of action is a specific outcome created by the acting agent. It is in this choosing process and decision making that both rationality and chance enter. The conclusion is that rationality is the element which links intentionality with goal seeking and attainment, but that the actual choice is determined by a complex interactive process in which both logic and chance play a part. [source] Null model analysis of communities on gradientsJOURNAL OF BIOGEOGRAPHY, Issue 6 2004James G. Sanderson Abstract Aim, I employed a novel null model and metric to uncover unusual species co-occurrence patterns in a herpetofaunal assemblage of 49 species collected at discrete elevations along a gradient. Location, Mount Kupe, Cameroon. Methods, Using a construction algorithm that started from a matrix of 0s, a sample null space of 25,000 unique null matrices was generated by simultaneously conserving (1) the number of occurrences of each species, (2) site richness and (3) species range spans derived from the observed incidence matrix. I then compared the number of times each pair of confamilial species co-occurred in the null space with the same number derived from the observed incidence matrix. Two cases dealing with embedded absences in species ranges were tested: (1) embedded absences were maintained, and (2) embedded absences were assumed to be sampling omissions and were replaced by presences. Results, In the observed absence/presence assemblage there were 147 possible confamilial species pairs. Therefore, 5% or eight were expected by chance alone to have co-occurrence patterns that differed from chance expectations by chance alone. Of these confamilial species pairs, 38 were congeneric and so 5% or two were expected to differ from chance expectations. For case (1) 16, and for case (2) 17 confamilial species pairs' co-occurrence patterns differed significantly from chance expectations. For case (1) nine congeneric species pairs, and for case (2) 10 congeneric pairs differed significantly from chance expectations. For case (1) four, and for case (2) five congeneric species pairs formed checkerboards (patterns of mutual exclusion). Results from case (1) were a proper subset of case (2) indicating that sampling omissions did not alter greatly the results. Main conclusions, I have demonstrated that null models are valuable tools to analyse ecological communities provided that proper models are employed. The choice of the appropriate null space to analyse distributions is critical. The null model employed to analyse birds on islands of an archipelago can be adapted to analyse species along gradients provided an additional range constraint is added to the null model. Moreover, added precision to results can be obtained by analysing each species pair separately, particularly those in the same family or genus, as opposed to applying a community-wide metric to the faunal assemblage. My results support some of the speculations of previous authors who were unable to demonstrate their suspicions analytically. [source] Why do women have stress urinary incontinence?,,NEUROUROLOGY AND URODYNAMICS, Issue S1 2010John O.L. DeLancey Abstract This article reviews progress made in understanding the causes of stress urinary incontinence. Over the last century, several hypotheses have been proposed to explain stress urinary incontinence. These theories are based on clinical observations and focus primarily on the causative role of urethral support loss and an open vesical neck. Recently these hypotheses have been tested by comparing measurements of urethral support and function in women with primary stress urinary incontinence to asymptomatic volunteers who were recruited to be similar in age, race, and parity. Maximal urethral closure pressure is the parameter that differs the most between groups being 43% lower in women with stress incontinence than similar asymptomatic women having as effect size of 1.6. Measures of urethral support effect sizes range from 0.5 to 0.6. Because any one objective measure of support may not capture the full picture of urethrovesical mobility, review of blinded ultrasounds of movements during cough were reviewed by an expert panel. The panel was able to identify women with stress incontinence correctly 57% of the time; just 7% above the 50% that would be expected by chance alone, confirming that urethrovesical mobility is not strongly associated with stress incontinence. Although operations that provide differential support to the urethra are effective, urethral support is not the predominant cause of stress incontinence. Improving our understanding of factors affecting urethral closure may lead to novel treatments targeting the urethra and improved understanding of the small but persistent failure rate of current surgery. Neurourol. Urodynam. 29:S13,S17, 2010. © 2010 Wiley-Liss, Inc. [source] Methylphenidate use in children and risk of cancer at 18 sites: results of surveillance analyses,PHARMACOEPIDEMIOLOGY AND DRUG SAFETY, Issue 12 2007Nina Oestreicher PhD Abstract Purpose A recent report linked methylphenidate (MPH) use in children to cytologic abnormalities in plasma lymphocytes, a possible cancer biomarker. The purpose of this study was to investigate the association of MPH use and childhood cancer risk. Methods Using automated pharmacy databases and the SEER-affiliated cancer registry of the Kaiser Permanente Medical Care Program (KPMCP), we compared cancer rates at 18 sites among 35 400 MPH users who received it before age 20 to rates among KPMCP membership (age, sex, and calendar year standardized). Medical records of MPH exposed cancer cases were reviewed to identify the presence of established risk factors. Results There were 23 cancers among MPH users, versus 20.4 expected (standardized morbidity ratio, SMR,=,1.13, 95% confidence interval (0.72, 1.70)). Given the small number of cancers, site-specific SMR estimates were imprecise. Only one SMR was statistically significant at the p,<,0.05 level, which given the number of comparisons is consistent with the absence of a true association at any site. MPH use was associated with increased risk of lymphocytic leukemia (SMR,=,2.64 (1.14, 5.20)), based on eight observed cases). The medical records of these exposed cases did not reveal any lymphocytic leukemia risk factors (prior cancer, radiotherapy or chemotherapy, or Down syndrome). Conclusions Our results are consistent with no moderate or strong association between MPH use and cancer risk in children, although our ability to examine dose and duration of use or risk at specific sites was limited by small numbers. Further study of MPH use and lymphocytic leukemia risk is needed to determine whether our results are due to chance alone. Copyright © 2007 John Wiley & Sons, Ltd. [source] Assessing teratogenicity of antiretroviral drugs: monitoring and analysis plan of the Antiretroviral Pregnancy Registry,,PHARMACOEPIDEMIOLOGY AND DRUG SAFETY, Issue 8 2004Deborah L. Covington DrPH Abstract This paper describes the Antiretroviral Pregnancy Registry's (APR) monitoring and analysis plan. APR is overseen by a committee of experts in obstetrics, pediatrics, teratology, infectious diseases, epidemiology and biostatistics from academia, government and the pharmaceutical industry. APR uses a prospective exposure-registration cohort design. Clinicians voluntarily register pregnant women with prenatal exposures to any antiretroviral therapy and provide fetal/neonatal outcomes. A birth defect is any birth outcome ,20 weeks gestation with a structural or chromosomal abnormality as determined by a geneticist. The prevalence is calculated by dividing the number of defects by the total number of live births and is compared to the prevalence in the CDC's population-based surveillance system. Additionally, first trimester exposures, in which organogenesis occurs, are compared with second/third trimester exposures. Statistical inference is based on exact methods for binomial proportions. Overall, a cohort of 200 exposed newborns is required to detect a doubling of risk, with 80% power and a Type I error rate of 5%. APR uses the Rule of Three: immediate review occurs once three specific defects are reported for a specific exposure. The likelihood of finding three specific defects in a cohort of ,600 by chance alone is less than 5% for all but the most common defects. To enhance the assurance of prompt, responsible, and appropriate action in the event of a potential signal, APR employs the strategy of ,threshold'. The threshold for action is determined by the extent of certainty about the cases, driven by statistical considerations and tempered by the specifics of the cases. Copyright © 2004 John Wiley & Sons, Ltd. [source] Mortality patterns among workers exposed to arsenic, cadmium, and other substances in a copper smelterAMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 8 2009Gary M. Marsh PhD Abstract Objective To evaluate the long-term mortality experience of workers exposed to arsenic, cadmium, and other substances at a copper mine and smelter in Copperhill, Tennessee studied earlier as part of an industry-wide study. Methods Subjects were 2,422 male workers employed three or more years in the smelter or mill between 1/1/46 until the plant strike and scale-down of operations in April 1996. Vital status was determined through 2000 for 99.4% of subjects and cause of death for 91.3% of 878 deaths. Historical exposures were estimated for lead, SO2, arsenic, cadmium, dust, and cobalt. We computed standardized mortality ratios (SMRs) based on U.S. and local county rates and modeled internal relative risks (RRs). Results We observed overall deficits in deaths based on national and local county comparisons from all causes, all cancers and most of the cause of death categories examined. We found limited evidence of increasing mortality risks from cerebrovascular disease with increasing duration and cumulative arsenic exposure, but no evidence of an exposure,response relationship for cadmium exposure and bronchitis. Conclusions Our limited evidence of an association between inhaled arsenic exposure and CVD is an exploratory finding not observed in other epidemiology studies of more highly exposed occupational populations. Possible alternative explanations include chance alone and uncontrolled confounding or effect modification by co-exposures or other factors correlated with arsenic exposure and unique to the Copperhill facility. Am. J. Ind. Med. 52:633,644, 2009. © 2009 Wiley-Liss, Inc. [source] Conflicting Preferences: A Reason Fertility Tends to Be Too High or Too LowPOPULATION AND DEVELOPMENT REVIEW, Issue 4 2003David Voas Fertility has often seemed to be too high or too low, relative not only to social and economic goals, but also to reproductive preferences. In developing countries actual fertility has often been higher than desired family size, while in developed societies fertility tends to be below replacement level even though people generally say that they want at least two children. In explanations of fertility extremes, or of the discrepancies between desired and actual fertility, the effect of partners' holding different preferences has tended to be overlooked. Individual preferences expected to lead to replacement-level reproduction may in combination generate substantially higher or lower fertility. In explaining such outcomes, a crucial question is what happens when spousal preferences diverge. Given that personal practices or social norms may systematically favor high or low preferences in the event of disagreement, chance alone will ensure that desired and actual fertility do not coincide. [source] The genetics of twinning: From splitting eggs to breaking paradigms,AMERICAN JOURNAL OF MEDICAL GENETICS, Issue 2 2009Natasha Shur Abstract Over the last decades, there has been a twin boom in terms of live births. Meanwhile, new insights into the genetics of twinning have changed major paradigms. The first major paradigm is that monozygotic (MZ) twins are identical. The second is that twins are either MZ or dizygotic (DZ). The third is that MZ twins happen by chance alone. We have discovered striking epigenetic and other differences between seemingly alike individuals; the presence of fascinating intermediate twin forms; and the potential for familial MZ twinning and even a twinning gene. As this article discusses, the aforementioned paradigm shifts have influenced novel research directions and improved clinical approaches to twin-management. © 2009 Wiley-Liss, Inc. [source] Multiple measures of laterality in Garnett's bushbaby (Otolemur garnettii)AMERICAN JOURNAL OF PRIMATOLOGY, Issue 3 2010David B. Hanbury Abstract Behavioral laterality, a common measure of hemispheric specialization of the brain, has been examined in multiple tasks across several species of prosimian primates; however, there is inconsistency among findings between and within species that leaves many questions about laterality unanswered. Most studies have employed few measures of laterality, most commonly handedness. This study examined multiple measures of laterality within subjects in 17 captive-born Garnett's bushbabies (Otolemur garnettii) to assess the consistency of lateralized behaviors and to examine possible influences such as age, posture, novelty, and arousal to elucidate the relations between direction and strength of laterality. We measured reaching, turning bias, scent marking, tail wrapping, leading foot, side-of-mouth preference, and hand use in prey capture. Because autonomic arousal has been invoked as a determinant of strength of lateralization, we included multiple tasks that would allow us to test this hypothesis. All subjects were significantly lateralized on simple reaching tasks (P<0.01) and tail wrapping (P<0.01). Moreover, the number of animals lateralized on turning (P<0.01), leading limb (P<0.05), mouth use (P<0.01), and prey capture (P<0.01) was greater than would be expected by chance alone. There was consistency in the strength and direction of hand biases across different postures. Tasks requiring hand use were more strongly lateralized than tasks not involving hand use (P<0.001). The data do not support the assumption that arousal (as subjectively categorized) or novelty strengthens lateralized responding. The results of this study are discussed in terms of the effects of arousal, posture, and age on lateralized behavior. Am. J. Primatol. 72:206,216, 2010. © 2009 Wiley-Liss, Inc. [source] | ||||||||||||||||