Distribution by Scientific Domains
Distribution within Medical Sciences

Kinds of Prior

  • dirichlet process prior
  • informative prior
  • non-informative prior
  • noninformative prior
  • process prior
  • reference prior
  • shrinkage prior
  • year prior

  • Terms modified by Prior

  • prior activation
  • prior application
  • prior assumption
  • prior attempt
  • prior belief
  • prior caesarean section
  • prior cancer
  • prior chemotherapy
  • prior commitment
  • prior conviction
  • prior data
  • prior density
  • prior diagnosis
  • prior distribution
  • prior episode
  • prior estimate
  • prior evidence
  • prior expectation
  • prior experience
  • prior exposure
  • prior finding
  • prior fracture
  • prior history
  • prior hypothesis
  • prior information
  • prior investigation
  • prior knowledge
  • prior literature
  • prior model
  • prior models
  • prior myocardial infarction
  • prior pregnancy
  • prior probability
  • prior radiation therapy
  • prior radiotherapy
  • prior record
  • prior report
  • prior research
  • prior research shows
  • prior result
  • prior stroke
  • prior studies
  • prior study
  • prior suicide attempt
  • prior surgery
  • prior therapy
  • prior training
  • prior trauma
  • prior treatment
  • prior use
  • prior work
  • prior year

  • Selected Abstracts

    Bargaining without a Common Prior,An Immediate Agreement Theorem

    ECONOMETRICA, Issue 3 2003
    Muhamet Yildiz
    In sequential bargaining models without outside options, each player's bargaining power is ultimately determined by which player will make an offer and when. This paper analyzes a sequential bargaining model in which players may hold different beliefs about which player will make an offer and when. Excessive optimism about making offers in the future can cause delays in agreement. The main result states that, despite this, if players will remain sufficiently optimistic for a sufficiently long future, then in equilibrium they will agree immediately. This result is also extended to other canonical models of optimism. [source]

    Pharmacoeconomics of Gastrointestinal Drug Utilisation Prior and Post Helicobacter pylori Eradication

    HELICOBACTER, Issue 1 2004
    Rogier M. Klok
    ABSTRACT Background., Eradication of Helicobacter pylori prevents recurrence of peptic ulcer. In pharmacoeconomic analyses it is often presumed that after successful eradication no more gastrointestinal drugs are used. We investigated this presumed positive monetary effect using General Practitioners prescribing data, including information in diagnosis. Methods., From the RNG-database we identified patients with a H. pylori eradication in the years 1997,2000. H. pylori eradication was defined as a prescription of two antibiotics and one gastrointestinal drug on the same day. Patients were divided into a group with diagnosed ulcers and a group without diagnosed ulcers. Gastrointestinal drug costs were calculated for 4 months prior to eradication and 9,12 months post eradication. For comparison costs in all periods were expressed per patient per period. For statistical analysis the paired t -test was used. Results., One hundred and two patients were eligible for evaluation. Of these patients 35 had a diagnosed ulcer and 67 had not. Generally the number of patients on gastrointestinal drugs decreased (61% prior vs. 33% post), however, the drug costs did not change (,33 prior vs. ,34 post). Costs for proton pump inhibitors increased post eradication (,14 prior vs. ,28 post). The ulcer and nonulcer group showed similar results. Conclusion.,Helicobacter pylori eradication is thought to be cost effective, however, we did not find a decrease in costs for all gastrointestinal drugs. There may be a great pharmacoeconomical advantage when it is possible to predict which patients are more likely to ,fail' eradication therapy. [source]

    Defining the Jacobean Church: The Politics of Religious Controversy, 1603,1625 By Charles W. A. Prior

    HISTORY, Issue 305 2007
    No abstract is available for this article. [source]

    The Courts of the Prior and the Bishop of Durham in the Later Middle Ages

    HISTORY, Issue 278 2000
    Cynthia J. Neville
    The operation of the common law in late medieval county Durham was characterized by several unique features. Among these were the independence of episcopal officials from interference from royal agents in the execution of the law, and the great variety of temporal courts found there. Within the lands of the palatinate, jurisdiction over suspects accused of felony was shared by both the bishop and the prior of Durham. The origins of this unusual division of judicial authority was an agreement dated c.1229, known as Le Convenit. It defined the relationship between the bishop, the temporal lord of the palatinate, and the prior of the Benedictine monastery in Durham who, as a landholder second only to the bishop, held a separate court for the suit of his free tenants. That relationship was often fraught with tension, for both lords were jealous of the prestige , and the revenues , incumbent on the exercise of judicial authority in their lands. This article examines the origins of Le Convenit, and the consequences of the agreement on criminal legal procedure in late medieval Durham. Successive priors of the monastery struggled tirelessly against the bishops to preserve the privileges they won in 1229, and Le Convenit remained throughout this period a potent weapon in their determination to give expression to lordly power and authority. [source]

    Nutriose, a prebiotic low-digestible carbohydrate, stimulates gut mucosal immunity and prevents TNBS-induced colitis in piglets,

    Philippe R. Pouillart PhD
    Abstract Background: We investigated a prebiotic low-digestible carbohydrate (LDC) as a possible food ingredient to stimulate bowel functions in the treatment of inflammatory bowel disease. The study aimed to assess a fermentable dextrin fiber (Nutriose) and its relationship to the immune management of the disease and the microbiota profile in colitis-bearing piglets. Methods: In a randomized placebo-controlled parallel blind preclinical study, 32 male piglets were fed LDC (4% Nutriose) or dextrose placebo for 44 days before being challenged with trinitrobenzene sulfonic acid (TNBS) to induce colitis. We followed the microbiota profile using real-time polymerase chain reaction (PCR) targeted to 9 bacterial genera. Secretory IgA was evaluated by enzyme-linked immunosorbent assay (ELISA). Inflammatory protein profiles were monitored in blood and colonic tissues. Both histological scoring of biopsy samples and live endoscopic scoring were used to measure colitis development. Results: Prior and continuing LDC supplementation alleviated the symptoms of colitis (body weight loss, bloody stools) induced by a TNBS challenge. This effect was associated with an improvement in endoscopic and histological scores. LDC was shown to selectively downregulate some of the proinflammatory factors and their concomitant pyretic events and to stimulate the Th2-related immune pathway (IL-10 and s-IgA). Conclusions: At the dose tested, LDC is a well-tolerated prebiotic agent able to not only stimulate butyrogenic bacteria strains and reduce intestinal transit disorders and energy intake, but also to prevent chronic inflammatory intestinal injuries. Inflamm Bowel Dis 2010 [source]

    Cardiovascular Actions of Orexin-A in the Rat Subfornical Organ

    P. M. Smith
    Orexin-A is a neuropeptide, primarily produced in the lateral hypothalamic/perifornical hypothalamus. Orexin receptors and immunoreactive neuronal fibres are widely distributed throughout the brain, suggesting integrative neurotransmitter roles in a variety of physiological systems. Intracerebroventricular injections of orexin-A increase blood pressure and stimulate drinking, and the subfornical organ (SFO), a circumventricular structure implicated in autonomic control, is a potential site at which orexin may act to exert these effects. We have therefore used microinjection techniques to examine the effects of orexin-A administered directly into the SFO on blood pressure and heart rate in urethane anaesthetised male Sprague-Dawley rats. Orexin-A microinjection (50 fmol) into the SFO caused site-specific decreases in blood pressure (SFO: mean area under curve (AUC) = ,681.7 ± 46.8 mmHg*s, n = 22 versus non-SFO: 63.68 ± 54.69 mmHg*s, n = 15, P < 0.001), and heart rate (SFO: mean AUC = ,26.7 ± 2.8 beats, n = 22, versus non-SFO: mean AUC = 1.62 ± 2.1 beats, n = 15, P < 0.001). Vagotomy did not alter the hypotensive or bradycardic responses elicited by orexin-A microinjection. Prior ,-adrenoceptor blockade with phenoxybenzamine (1 mg/kg, i.v.) masked the orexin-A induced blood pressure (mean AUC = ,122.6 ± 17.6 mmHg*s, n = 4, P < 0.01 paired t-test) and heart rate (mean AUC = ,6.7 ± 1.7 beats, n = 4, P < 0.05, paired test) response. The orexin-A induced heart rate response was attenuated when ,-adrenoceptors were blocked with propranolol (1 mg/kg, i.v.; mean AUC = 0.6 ± 2.8 beats, n = 5, P < 0.01 paired t-test). These studies demonstrate that microinjection of orexin-A into the SFO causes site specific decreases in blood pressure and heart rate which is mediated by a reduction in sympathetic tone. [source]

    Bayesian Finite Markov Mixture Model for Temporal Multi-Tissue Polygenic Patterns

    Yulan Liang
    Abstract Finite mixture models can provide the insights about behavioral patterns as a source of heterogeneity of the various dynamics of time course gene expression data by reducing the high dimensionality and making clear the major components of the underlying structure of the data in terms of the unobservable latent variables. The latent structure of the dynamic transition process of gene expression changes over time can be represented by Markov processes. This paper addresses key problems in the analysis of large gene expression data sets that describe systemic temporal response cascades and dynamic changes to therapeutic doses in multiple tissues, such as liver, skeletal muscle, and kidney from the same animals. Bayesian Finite Markov Mixture Model with a Dirichlet Prior is developed for the identifications of differentially expressed time related genes and dynamic clusters. Deviance information criterion is applied to determine the number of components for model comparisons and selections. The proposed Bayesian models are applied to multiple tissue polygenetic temporal gene expression data and compared to a Bayesian model-based clustering method, named CAGED. Results show that our proposed Bayesian Finite Markov Mixture model can well capture the dynamic changes and patterns for irregular complex temporal data (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    ,Thank Goodness That's Over': The Evolutionary Story

    RATIO, Issue 3 2002
    James Maclaurin
    If, as the new tenseless theory of time maintains, there are no tensed facts, then why do our emotional lives seem to suggest that there are? This question originates with Prior's ,Thank Goodness That's Over' problem, and still presents a significant challenge to the new B,theory of time. We argue that this challenge has more dimensions to it than has been appreciated by those involved in the debate so far. We present an analysis of the challenge, showing the different questions that a B,theorist must answer in order to meet it. The debate has focused on the question of what is the object of my relief when an unpleasant experience is past. We outline the prevailing response to this question. The additional, and neglected, questions are, firstly ,,Why does the same event elicit different emotional responses from us depending on whether it is in the past, present, or future?' And secondly ,,Why do we care more about proximate future pain than about distant future pain?' We give B,theory answers to these questions, which appeal to evolutionary considerations. [source]

    Reference and probability-matching priors in Bayesian analysis of mixed linear models

    A. L. Pretorius
    Summary Determination of reasonable non-informative priors in multiparameter problems is not easy; common non-informative priors, such as Jeffrey's prior, can have features that have an unexpectedly dramatic effect on the posterior. In recognition of this problem Berger and Bernardo (Bayesian Statistics IV. Oxford University Press, Oxford, UK, pp. 35,70, 1992), proposed the Reference Prior approach to the development of non-informative priors. In the present paper the reference priors of Berger and Bernardo (1992) are derived for the mixed linear model. In spite of these difficulties, there is growing evidence, mainly through examples that reference priors provide ,sensible' answers from a Bayesian point of view. We also examine whether the reference priors satisfy the probability-matching criterion. The theory and results are applied to a real problem consisting of 879 weaning weight records, from the progeny of 17 sires. These important aspects are explored via Monte Carlo simulations. Zusammenfassung Reference und Probability-Matching Priors in Bayesian Analysen von gemischten linearen Modellen Die Festlegung von vernünftigen Non-Informative Priors in Multi-Paramter Analysen ist nicht leicht; gewöhnliche Non-Informative Priors, wie beispielsweise Jeffrey's Priors, können unerwartete dramatische Effekte auf die Lösungen haben. Zur Lösung dieses Problems schlagen Berger and Bernardo (Bayesian Statistics IV. Oxford University Press, Oxford, UK, pp. 35,70, 1992) den Reference Prior Ansatz zur Entwicklung von Non-Informative Priors vor. In der vorliegenden Untersuchung werden die von Berger and Bernardo (1992) vorgeschlagenen Reference Priors in linearen gemischten Modellen angewandt. Trotz der bekannten Schwierigkeiten gibt es hauptsächlich anhand von Beispielen mehr und mehr Anhaltspunkte, dass die Reference Priors aus der Sicht von Bayesians zu brauchbaren Antworten führen. Es wurde auch untersucht, ob diese Reference Priors den Probability-Matching Kriterien genügen. Die Theorie und die Ergebnisse sind an einem Beispiel mit 879 Datensätzen mit Absatzgewichten von Schafen, die von 17 Böcken abstammen, verifiziert worden. Die wichtigen Aspekte sind mittels Monte Carlo Simulation untersucht worden. [source]

    Default Bayesian Priors for Regression Models with First-Order Autoregressive Residuals

    Malay Ghosh
    Abstract. The objective of this paper is to develop default priors when the parameter of interest is the autocorrelation coefficient in normal regression models with first-order autoregressive residuals. Jeffreys' prior as well as reference priors are found. These priors are compared in the light of how accurately the coverage probabilities of Bayesian credible intervals match the corresponding frequentist coverage probabilities. It is found that the reference priors have a definite edge over Jeffreys' prior in this respect. Also, the credible intervals based on these reference priors seem superior to similar intervals based on certain divergence measures. [source]

    Capture,Recapture Estimation Using Finite Mixtures of Arbitrary Dimension

    BIOMETRICS, Issue 2 2010
    Richard Arnold
    Summary Reversible jump Markov chain Monte Carlo (RJMCMC) methods are used to fit Bayesian capture,recapture models incorporating heterogeneity in individuals and samples. Heterogeneity in capture probabilities comes from finite mixtures and/or fixed sample effects allowing for interactions. Estimation by RJMCMC allows automatic model selection and/or model averaging. Priors on the parameters stabilize the estimates and produce realistic credible intervals for population size for overparameterized models, in contrast to likelihood-based methods. To demonstrate the approach we analyze the standard Snowshoe hare and Cottontail rabbit data sets from ecology, a reliability testing data set. [source]

    Bayesian Hierarchical Functional Data Analysis Via Contaminated Informative Priors

    BIOMETRICS, Issue 3 2009
    Bruno Scarpa
    Summary A variety of flexible approaches have been proposed for functional data analysis, allowing both the mean curve and the distribution about the mean to be unknown. Such methods are most useful when there is limited prior information. Motivated by applications to modeling of temperature curves in the menstrual cycle, this article proposes a flexible approach for incorporating prior information in semiparametric Bayesian analyses of hierarchical functional data. The proposed approach is based on specifying the distribution of functions as a mixture of a parametric hierarchical model and a nonparametric contamination. The parametric component is chosen based on prior knowledge, while the contamination is characterized as a functional Dirichlet process. In the motivating application, the contamination component allows unanticipated curve shapes in unhealthy menstrual cycles. Methods are developed for posterior computation, and the approach is applied to data from a European fecundability study. [source]

    Modeling Longitudinal Spatial Periodontal Data: A Spatially Adaptive Model with Tools for Specifying Priors and Checking Fit

    BIOMETRICS, Issue 3 2008
    Brian J. Reich
    Summary Attachment loss (AL), the distance down a tooth's root that is no longer attached to surrounding bone by periodontal ligament, is a common measure of periodontal disease. In this article, we develop a spatiotemporal model to monitor the progression of AL. Our model is an extension of the conditionally autoregressive (CAR) prior, which spatially smooths estimates toward their neighbors. However, because AL often exhibits a burst of large values in space and time, we develop a nonstationary spatiotemporal CAR model that allows the degree of spatial and temporal smoothing to vary in different regions of the mouth. To do this, we assign each AL measurement site its own set of variance parameters and spatially smooth the variances with spatial priors. We propose a heuristic to measure the complexity of the site-specific variances, and use it to select priors that ensure parameters in the model are well identified. In data from a clinical trial, this model improves the fit compared to the usual dynamic CAR model for 90 of 99 patients' AL measurements. [source]

    Calculation of Posterior Probabilities for Bayesian Model Class Assessment and Averaging from Posterior Samples Based on Dynamic System Data

    Sai Hung Cheung
    Because of modeling uncertainty, a set of competing candidate model classes may be available to represent a system and it is then desirable to assess the plausibility of each model class based on system data. Bayesian model class assessment may then be used, which is based on the posterior probability of the different candidates for representing the system. If more than one model class has significant posterior probability, then Bayesian model class averaging provides a coherent mechanism to incorporate all of these model classes in making probabilistic predictions for the system response. This Bayesian model assessment and averaging requires calculation of the evidence for each model class based on the system data, which requires the evaluation of a multi-dimensional integral involving the product of the likelihood and prior defined by the model class. In this article, a general method for calculating the evidence is proposed based on using posterior samples from any Markov Chain Monte Carlo algorithm. The effectiveness of the proposed method is illustrated by Bayesian model updating and assessment using simulated earthquake data from a ten-story nonclassically damped building responding linearly and a four-story building responding inelastically. [source]

    A Probabilistic Framework for Bayesian Adaptive Forecasting of Project Progress

    Paolo Gardoni
    An adaptive Bayesian updating method is used to assess the unknown model parameters based on recorded data and pertinent prior information. Recorded data can include equality, upper bound, and lower bound data. The proposed approach properly accounts for all the prevailing uncertainties, including model errors arising from an inaccurate model form or missing variables, measurement errors, statistical uncertainty, and volitional uncertainty. As an illustration of the proposed approach, the project progress and final time-to-completion of an example project are forecasted. For this illustration construction of civilian nuclear power plants in the United States is considered. This application considers two cases (1) no information is available prior to observing the actual progress data of a specified plant and (2) the construction progress of eight other nuclear power plants is available. The example shows that an informative prior is important to make accurate predictions when only a few records are available. This is also the time when forecasts are most valuable to the project manager. Having or not having prior information does not have any practical effect on the forecast when progress on a significant portion of the project has been recorded. [source]

    Real-Time OD Estimation Using Automatic Vehicle Identification and Traffic Count Data

    Michael P. Dixon
    A key input to many advanced traffic management operations strategies are origin,destination (OD) matricies. In order to examine the possibility of estimating OD matricies in real-time, two constrained OD estimators, based on generalized least squares and Kalman filtering, were developed and tested. A one-at-a-time processing method was introduced to provide an efficient organized framework for incorporating observations from multiple data sources in real-time. The estimators were tested under different conditions based on the type of prior OD information available, the type of assignment available, and the type of link volume model used. The performance of the Kalman filter estimators also was compared to that of the generalized least squares estimator to provide insight regarding their performance characteristics relative to one another for given scenarios. Automatic vehicle identification (AVI) tag counts were used so that observed and estimated OD parameters could be compared. While the approach was motivated using AVI data, the methodology can be generalized to any situation where traffic counts are available and origin volumes can be estimated reliably. The primary means by which AVI data was utilized was through the incorporation of prior observed OD information as measurements, the inclusion of a deterministic link volume component that makes use of OD data extracted from the latest time interval from which all trips have been completed, and through the use of link choice proportions estimated based on link travel time data. It was found that utilizing prior observed OD data along with link counts improves estimator accuracy relative to OD estimation based exclusively on link counts. [source]

    TROSY effects in MAS solid-state NMR

    Veniamin Chevelkov
    Abstract Use of transverse relaxation-optimized spectroscopy (TROSY) type techniques had a dramatic impact on the study of large proteins with a molecular weight >30kDa for solution-state NMR. In the solid-state, such an effect would not be expected a prior, as the investigated molecules are immobilized. However, local motions induce fluctuations of the local fields experienced by the nuclear spins and, this way, are effective for relaxation. We demonstrate that protein dynamics can significantly influence the resonance line width in ultra high resolution MAS (magic angle spinning) solid-state NMR experiments. Averaging of the 15NH,/, multiplet components as a consequence of 1H decoupling induces effective broadening of the 15N resonance. Application of TROSY type techniques that select only the narrow component of the multiplet pattern results in an increased resolution and, thus, will be of benefit for MAS solid-state NMR spectroscopy. © 2008 Wiley Periodicals, Inc. Concepts Magn Reson Part A 32A: 143,156, 2008. [source]

    Heart Failure Drug Utilization Patterns for Medicaid Patients Before and After a Heart Failure-Related Hospitalization

    Patricia A. Howard PharmD
    The authors examined heart failure (HF) drug utilization patterns in Medicaid patients before and after a HF-related hospitalization. This was a retrospective claims analysis of Kansas Medicaid beneficiaries hospitalized for HF between July 1, 2000, and March 31, 2001. HF drugs were tracked 6 months prior and 6 months following the admission. Angiotensin-converting enzyme (ACE) inhibitor doses were compared with target ranges. The cohort of 135 patients had a mean age of 53.6 years and was predominantly female (66.7%) and Caucasian (70.4%) with a high prevalence of cardiovascular comorbidities. Before hospitalization, less than one third of patients were receiving ACE inhibitors, angiotensin receptor blockers, , blockers, digoxin, or vasodilators. Following hospitalization, increased utilization was observed for , blockers, digoxin, and angiotensin receptor blockers, but overall usage remained low. ACE inhibitors and vasodilator use remained constant. ACE-inhibitor doses were below target ranges before and after hospitalization. In this Medicaid cohort, HF-related hospitalizations did not lead to improved HF therapy. [source]

    585-nm Pulsed Dye Laser in the Treatment of Surgical Scars Starting on the Suture Removal Day

    Keyvan Nouri MD
    Background The optimal time frame to improve the quality and cosmetic appearance of scars by laser therapy has not been clearly elucidated by prior controlled clinical trials. Objective To determine the efficacy of the 585-nm pulsed dye laser (PDL) in the treatment of surgical scars starting on the day of suture removal. Methods Eleven patients (skin types I,IV) with 12 postoperative linear scars that were greater than 2 cm were treated three times on monthly intervals with the 585-nm PDL (450 ,s, 10-mm spot size, 3.5 J/cm2 with 10% overlap) on one scar half, whereas the other half received no treatment. Scars were later evaluated by a blinded examiner using the Vancouver Scar Scale (VSS) for pigmentation, vascularity, pliability, and height. Scars were then blindly examined for cosmetic appearance using a visual analog scale. Results One month after the last treatment, final scar analysis by the blinded examiner revealed a significant difference between treated and untreated sites, with the treated halves scoring better in all scar parameters in the VSS and in cosmetic appearance. The treated halves demonstrated an overall average improvement in the VSS between the first treatment score and the final score of 54% versus 10% in the controls (P=0.0002). The cosmetic appearance score (0=worst; 10=best) at final assessment was significantly better for the treated scars, scoring 7.3 versus the averaged control score of 5.2 (P=0.016). Conclusion The 585-nm PDL is effective and safe in improving the quality and cosmetic appearance of surgical scars in skin types I,IV starting on the day of suture removal. [source]

    Is the dementia rate increasing in Beijing?

    Prevalence, incidence of dementia 10 years later in an urban elderly population
    Objective:, To examine the time trend of dementia morbidity over the past decade in Beijing, China. Method:, In 1997, 1593 community-dwelling elderly aged 60+ years were examined and followed-up over 2-years to identify incident dementia. A similar cohort study of dementia conducted in the same district 10 years prior was used as historical comparison to examine the time trend of dementia incidence. Results:, Forty prevalent dementia cases were identified at the initial examination for a prevalence of 2.51% (95% CI: 1.74,3.28) and 25 incident cases were identified at the follow-up visit for an incidence of 0.90% (0.55,1.25) among residents aged 60+ years. Alzheimer's dementia (AD) was the most common type of dementia in both prevalent and incident cases. Conclusion:, The prevalence and incidence rates of dementia in Beijing were slightly higher than those 10 years ago, which was partly because of population aging. AD became the most common subtype of dementia. [source]

    Longitudinal study of urinary albumin excretion in young diabetic patients,-Wessex Diabetic Nephropathy Project

    DIABETIC MEDICINE, Issue 5 2001
    S. Twyman
    Summary Aims This study was established to follow changes in albumin/creatinine ratio (ACR) and to determine the prevalence and degree of progression of microalbuminuria (MA) or of clinical proteinuria (CP) in children with Type 1 diabetes. The study has investigated subjects for up to 12 years in establishing the correlation between MA and gender, age, duration of diabetes and glycated haemoglobin (HbA1c). The study has defined clinical cut-offs for MA in daytime clinic urine samples in young diabetic subjects. Methods Three hundred and sixty-one patients were involved in the study, with 221 (61.2%) having over six sets of data. Urine samples were collected at routine annual clinic visits and analysed without prior freezing for ACR. Blood samples were taken for HbA1c measurement. Data including sex, age and duration of diabetes were recorded. Results A random clinic ACR of <,4.5 mg/mmol (males) and 5.2 mg/mmol (females) creatinine was used as the ,clinical cut-off' to define the presence of MA. The presence of MA was independent of HbA1c and duration of diabetes but appeared be associated with the adolescent years (> 10 years). There was little evidence of progression from normoalbuminuria to MA, or from MA to CP. Of patients aged 10,18 years, 30.9% of males and 40.4% of females had one or more episodes of MA. Conclusions Persistent MA and random episodes of MA or CP may be associated with the adolescent years but not with duration of diabetes. Further study will reveal if the substantial increases in ACR sometimes seen during adolescence are predictive of diabetic nephropathy. Clinical cut-offs of <,4.5 and <,5.2 mg/mmol creatinine for males and females, respectively, are suggested for the interpretation of changes in ACR in random urine samples in young people with Type 1 diabetes. [source]

    Davidson's Derangement: Of the Conceptual Priority of Language

    DIALECTICA, Issue 3 2001
    Karen Green
    Davidson has argued that the phenomenon of malapropism shows that languages thought of as social entities cannot be prior in the account of communication. This may be taken to imply that Dummett's belief, that language is prior in the account of thought, cannot be retained. This paper criticises the argument that takes Davidson from malapropism to the denial of the priority of language in the account of communication. It argues, against Davidson, that the distinction between word meaning and what speakers mean by words, used by Davidson to account for metaphor, suffices to account for malapropism. The reasons for the failure of Davidson's argument are used to throw light on what is meant by the priority of language over thought, and to argue that the priority thesis is ambiguous. [source]

    Has the Clinical Presentation and Clinician's Index of Suspicion of Cardiac Tamponade Changed Over the Past Decade?

    ECHOCARDIOGRAPHY, Issue 3 2008
    Sachin Gandhi M.D.
    It remains unclear whether advances in the understanding of the pathophysiology and improvements in cardiovascular imaging over the years have impacted the clinician's recognition of cardiac tamponade (CT). We sought to evaluate signs and symptoms of CT in a present-day population and compare it to a similar group from a decade prior. We performed a retrospective analysis of two cohorts of patients presenting to a tertiary hospital with CT, all of whom underwent pericardial drainage (PD). Group 1 (Gp1) included subjects presenting from 1988 to 1991 and Group 2 (Gp2) included subjects from 2002 to 2005. Fifty-five patients comprised each group, with an average age of 55 years. Seventy-one percent of patients in Gp1 had identifiable cardiovascular symptoms 1 week prior to presentation, compared to 33% in Gp2. Dyspnea was the most common symptom in both groups, and was less frequent in Gp2. Compared with Gp1, chest pain, cough, and lethargy were also less frequent in Gp2. One day prior to PD, tachypnea and pulsus paradoxus were detected more frequently in Gp1 compared to Gp2. Large, circumferential pericardial effusions were the most frequent echocardiographic findings in both groups and the most common etiology of CT was malignancy in Gp1and postoperative bleeding in Gp2. Thus, the recognition of symptoms and physical signs in patients presenting with CT has changed over the past decade, as has etiology of pericardial effusions. However, the diagnosis of CT still remains delayed, and the present data emphasize the need for a heightened index of suspicion for recognizing this hemodynamically-important process. [source]

    Possible Paradoxical Embolism as a Rare Cause for an Acute Myocardial Infarction

    ECHOCARDIOGRAPHY, Issue 5 2006
    Aleksandr Rovner M.D.
    Paradoxical embolus is a rare entity and it has been incriminated as a cause of both cryptogenic strokes and myocardial infarctions (MI). Herein, we present a case of a patient diagnosed with a pulmonary embolism 1 week prior who now presented with an acute MI. Subsequent evaluation revealed a patent foramen ovale and a large thrombus in the right pulmonary artery. It was presumed that the etiology of her infarct was due to paradoxical embolus. The management of the patient is discussed and the literature is reviewed. [source]

    Decision Theory Applied to an Instrumental Variables Model

    ECONOMETRICA, Issue 3 2007
    Gary Chamberlain
    This paper applies some general concepts in decision theory to a simple instrumental variables model. There are two endogenous variables linked by a single structural equation; k of the exogenous variables are excluded from this structural equation and provide the instrumental variables (IV). The reduced-form distribution of the endogenous variables conditional on the exogenous variables corresponds to independent draws from a bivariate normal distribution with linear regression functions and a known covariance matrix. A canonical form of the model has parameter vector (,, ,, ,), where ,is the parameter of interest and is normalized to be a point on the unit circle. The reduced-form coefficients on the instrumental variables are split into a scalar parameter ,and a parameter vector ,, which is normalized to be a point on the (k,1)-dimensional unit sphere; ,measures the strength of the association between the endogenous variables and the instrumental variables, and ,is a measure of direction. A prior distribution is introduced for the IV model. The parameters ,, ,, and ,are treated as independent random variables. The distribution for ,is uniform on the unit circle; the distribution for ,is uniform on the unit sphere with dimension k-1. These choices arise from the solution of a minimax problem. The prior for ,is left general. It turns out that given any positive value for ,, the Bayes estimator of ,does not depend on ,; it equals the maximum-likelihood estimator. This Bayes estimator has constant risk; because it minimizes average risk with respect to a proper prior, it is minimax. The same general concepts are applied to obtain confidence intervals. The prior distribution is used in two ways. The first way is to integrate out the nuisance parameter ,in the IV model. This gives an integrated likelihood function with two scalar parameters, ,and ,. Inverting a likelihood ratio test, based on the integrated likelihood function, provides a confidence interval for ,. This lacks finite sample optimality, but invariance arguments show that the risk function depends only on ,and not on ,or ,. The second approach to confidence sets aims for finite sample optimality by setting up a loss function that trades off coverage against the length of the interval. The automatic uniform priors are used for ,and ,, but a prior is also needed for the scalar ,, and no guidance is offered on this choice. The Bayes rule is a highest posterior density set. Invariance arguments show that the risk function depends only on ,and not on ,or ,. The optimality result combines average risk and maximum risk. The confidence set minimizes the average,with respect to the prior distribution for ,,of the maximum risk, where the maximization is with respect to ,and ,. [source]

    Expedient and Monotone Learning Rules

    ECONOMETRICA, Issue 2 2004
    Tilman Börgers
    This paper considers learning rules for environments in which little prior and feedback information is available to the decision maker. Two properties of such learning rules are studied: absolute expediency and monotonicity. Both require that some aspect of the decision maker's performance improves from the current period to the next. The paper provides some necessary, and some sufficient conditions for these properties. It turns out that there is a large variety of learning rules that have the properties. However, all learning rules that have these properties are related to the replicator dynamics of evolutionary game theory. For the case in which there are only two actions, it is shown that one of the absolutely expedient learning rules dominates all others. [source]

    Ketamine use, cognition and psychological wellbeing: a comparison of frequent, infrequent and ex-users with polydrug and non-using controls

    ADDICTION, Issue 1 2009
    Celia J. A. Morgan
    ABSTRACT Introduction Preliminary research has indicated that recreational ketamine use may be associated with marked cognitive impairments and elevated psychopathological symptoms, although no study to date has determined how these are affected by differing frequencies of use or whether they are reversible on cessation of use. In this study we aimed to determine how variations in ketamine use and abstention from prior use affect neurocognitive function and psychological wellbeing. Method We assessed a total of 150 individuals: 30 frequent ketamine users, 30 infrequent ketamine users, 30 ex-ketamine users, 30 polydrug users and 30 controls who did not use illicit drugs. Cognitive tasks included spatial working memory, pattern recognition memory, the Stockings of Cambridge (a variant of the Tower of London task), simple vigilance and verbal and category fluency. Standardized questionnaires were used to assess psychological wellbeing. Hair analysis was used to verify group membership. Results Frequent ketamine users were impaired on spatial working memory, pattern recognition memory, Stockings of Cambridge and category fluency but exhibited preserved verbal fluency and prose recall. There were no differences in the performance of the infrequent ketamine users or ex-users compared to the other groups. Frequent users showed increased delusional, dissociative and schizotypal symptoms which were also evident to a lesser extent in infrequent and ex-users. Delusional symptoms correlated positively with the amount of ketamine used currently by the frequent users. Conclusions Frequent ketamine use is associated with impairments in working memory, episodic memory and aspects of executive function as well as reduced psychological wellbeing. ,Recreational' ketamine use does not appear to be associated with distinct cognitive impairments although increased levels of delusional and dissociative symptoms were observed. As no performance decrements were observed in the ex-ketamine users, it is possible that the cognitive impairments observed in the frequent ketamine group are reversible upon cessation of ketamine use, although delusional symptoms persist. [source]

    Nonylphenols in sediments and effluents associated with diverse wastewater outfalls,

    Robert C. Hale
    Abstract Nonylphenols (NPs) have been reported to disrupt endocrine function and sexual development in aquatic organisms at low concentrations. Environmental NP burdens are predominantly derived from degradation of nonylphenol polyethoxylate surfactants. We detected NPs in discharge-associated riverine sediments adjacent to 11 of 20 active sewage treatment plants (STPs) at concentrations up to 12,400 ,g/kg. While most previous studies have focused on STPs, nonylphenols were observed in association with a variety of outfall types. The highest sediment burden, 14,100 ,g/kg, was detected near a federal facility's stormwater discharge. Of 75 sediments examined from 67 sites, 45% contained NP concentrations >5 ,g/kg; median concentration in these NP-positive sediments was 369 ,g/kg. Other surfactant-derived alkylphenolic compounds, specifically 4- tert -octylphenol and 4-cumylphenol, were observed in two sediments at 8,220 and 70,000 ,g/kg, respectively. The maximum NP concentration detected in an effluent, 6,300 ,g/L, was from a shipyard oil/water separator. Nonylphenols were detected (> 1.0 ,g/L) in 20% of the 59 effluents examined; 10% exceeded 10 ,g/L. Sediments sampled near a STP that had ceased treatment operations 20 years prior contained 54,000 ,g/kg, indicative of long-term NP residence. Results indicate that NPs may be released from diverse sources, concentrate in associated sediments, and persist therein for extended periods. [source]

    Comparison of three expert elicitation methods for logistic regression on predicting the presence of the threatened brush-tailed rock-wallaby Petrogale penicillata

    ENVIRONMETRICS, Issue 4 2009
    Rebecca A. O'Leary
    Abstract Numerous expert elicitation methods have been suggested for generalised linear models (GLMs). This paper compares three relatively new approaches to eliciting expert knowledge in a form suitable for Bayesian logistic regression. These methods were trialled on two experts in order to model the habitat suitability of the threatened Australian brush-tailed rock-wallaby (Petrogale penicillata). The first elicitation approach is a geographically assisted indirect predictive method with a geographic information system (GIS) interface. The second approach is a predictive indirect method which uses an interactive graphical tool. The third method uses a questionnaire to elicit expert knowledge directly about the impact of a habitat variable on the response. Two variables (slope and aspect) are used to examine prior and posterior distributions of the three methods. The results indicate that there are some similarities and dissimilarities between the expert informed priors of the two experts formulated from the different approaches. The choice of elicitation method depends on the statistical knowledge of the expert, their mapping skills, time constraints, accessibility to experts and funding available. This trial reveals that expert knowledge can be important when modelling rare event data, such as threatened species, because experts can provide additional information that may not be represented in the dataset. However care must be taken with the way in which this information is elicited and formulated. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    Complementary and alternative medicine practitioner consultations among those who have or have had cancer in a Norwegian total population (Nord-Trøndelag Health Study): prevalence, socio-demographics and health perceptions

    A. STEINSBEKK phd, research fellow
    STEINSBEKK A., ADAMS J., SIBBRITT D. & JOHNSEN R. (2010) European Journal of Cancer Care19, 346,351 Complementary and alternative medicine practitioner consultations among those who have or have had cancer in a Norwegian total population (Nord-Trøndelag Health Study): prevalence, socio-demographics and health perceptions The aim of the study was to identify the use of complementary and alternative medicine (CAM) practitioners among current and previous cancer patients in a total population. A secondary analysis of data from the Nord-Trøndelag Health Study (otherwise known as the HUNT 2 Study) , a total population survey conducted in central Norway , was undertaken. Analysis focused upon the response of 1406 individuals who reported to have or have had cancer and who answered a question on visits to CAM practitioners. The study identified 16.1% of respondents had visited a CAM practitioner in the prior 12 months compared with 12.8% in the total population, and the likelihood of consulting a CAM practitioner was significantly increased among those who had a university degree, who reported a lower perceived global health and who had experienced a health complaint during the last 12 months. Complementary and alternative medicine practitioner consultations among individuals with a previous or current malignant disease were highest for those with poor self-reported health status and with a recent health complaint. From the socio-demographic variables studied only the reporting of a university degree was significantly associated with higher CAM practitioner use. [source]