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Expected Rate (expected + rate)
Selected AbstractsEffect of Analysts' Optimism on Estimates of the Expected Rate of Return Implied by Earnings ForecastsJOURNAL OF ACCOUNTING RESEARCH, Issue 5 2007PETER D. EASTON ABSTRACT Recent literature has used analysts' earnings forecasts, which are known to be optimistic, to estimate implied expected rates of return, yielding upwardly biased estimates. We estimate that the bias, computed as the difference between the estimates of the implied expected rate of return based on analysts' earnings forecasts and estimates based on current earnings realizations, is 2.84%. The importance of this bias is illustrated by the fact that several extant studies estimate an equity premium in the vicinity of 3%, which would be eliminated by the removal of the bias. We illustrate the point that cross-sample differences in the bias may lead to the erroneous conclusion that cost of capital differs across these samples by showing that analysts' optimism, and hence, bias in the implied estimates of the expected rate of return, differs with firm size and with analysts' recommendation. As an important aside, we show that the bias in a value-weighted estimate of the implied equity premium is 1.60% and that the unbiased value-weighted estimate of this premium is 4.43%. [source] A Risk Adjusted Method for Comparing Adverse Outcomes among Practitioners in Pediatric and Congenital Cardiac CatheterizationCONGENITAL HEART DISEASE, Issue 4 2008Lisa Bergersen MD ABSTRACT Objective., We sought to develop a method to adjust for case mix diversity and allow comparison of adverse outcome rates among practitioners in pediatric and congenital cardiac catheterization. Patients and Methods., A single institutional database that captured demographic and procedural data was used to identify patient and procedural characteristics associated with adverse events (AE) and any high severity event classified as preventable or possibly preventable (P/PP). Diagnostic and procedural risk groups were created and indicators of hemodynamic vulnerability were defined. Expected event rates by the practitioners adjusting for case mix were calculated. Standardized adverse event ratios (SAER), defined as the observed rate divided by the expected rate for each practitioner were calculated with 95% confidence intervals. Results., The database included 1727 hemodynamic (30%) and interventional (70%) cases performed by seven practitioners in 18 months. During 147 cases, at least one P/PP AE occurred; among the seven practitioners observed, event rates ranged from 3.2 to 14.2%. In multivariable analysis, risk factors for all P/PP events included highest procedure risk group (odds ratio [OR] 2.1 for group 2, and 2.8 for group 3, relative to group 1, P = .001 and P < .001, respectively) and weight less than 4 kg (OR 2.8, P < .001). High severity P/PP events occurred in 67 cases with rates ranging from 2.0 to 6.6% by the practitioners. For these events, risk factors included: highest procedure risk group (OR 4.5 for group 2, and 4.9 for group 3, both P < .001) and an indicator of hemodynamic vulnerability (OR 1.8, P = .026). For the seven practitioners, the SAER ranged from 0.41 to 1.32 for any P/PP AE and from 0.69 to 1.44 for P/PP high severity events. In this cohort, we did not identify any statistically significant performance differences. Conclusion., Despite wide variations in case mix complexity in pediatric and congenital cardiac catheterization, this study demonstrates a method for risk adjustment which allows equitable comparisons among practitioners at a single institution. [source] Age,environment model for breast cancerENVIRONMETRICS, Issue 3 2004Nobutane Hanayama Abstract In the field of breast cancer study, it has become accepted that crucial exposures to environmental risks might have occurred years before a malignant tumor is evident in human breasts, while age factors such as ages at menstruation have been known as risks for the disease already. To project trends in two such kinds of risks for the disease, the concept of environment effects is introduced for (age, period)-specific breast cancer mortality rates. Also, a new model, named the age,environment (AE) model, which assumes that the logarithm of the expected rate is a linear function of environment effects and age effects, is proposed. It is shown that, although environment effects have different meanings from period effects or cohort effects, in the age,period,cohort (APC) model, the range space of the design matrix for the AE model is included in that for APC model. It is seen, however, that the AE model provides a better fit to the data for females in Japan and the four Nordic countries than does the APC model in terms of AIC. From the results of ML estimation of the parameters in the AE model based on the data obtained in Japan, we see high levels of environment effects associated with the Sino,Japanese war, World War II and the environmental pollution due to the economy in the recovery period from the defeat. Besides, from those based on the data obtained in the four Nordic countries, we see high levels of environment effects associated with the environment becoming worse after the year of Helsinki Olympics and low levels of them associated with the period including the year of ,Miracle of the Winter War' in Finland. Copyright © 2004 John Wiley & Sons, Ltd. [source] Transfer of hydrocarbons from natural seeps to the water column and atmosphereGEOFLUIDS (ELECTRONIC), Issue 2 2002I. R. MacDonald Abstract Results from surface geochemical prospecting, seismic exploration and satellite remote sensing have documented oil and gas seeps in marine basins around the world. Seeps are a dynamic component of the carbon cycle and can be important indicators for economically significant hydrocarbon deposits. The northern Gulf of Mexico contains hundreds of active seeps that can be studied experimentally with the use of submarines and Remotely Operated Vehicles (ROV). Hydrocarbon flux through surface sediments profoundly alters benthic ecology and seafloor geology at seeps. In water depths of 500,2000 m, rapid gas flux results in shallow, metastable deposits of gas hydrate, which reduce sediment porosity and affect seepage rates. This paper details the processes that occur during the final, brief transition , as oil and gas escape from the seafloor, rise through the water and dissolve, are consumed by microbial processes, or disperse into the atmosphere. The geology of the upper sediment column determines whether discharge is rapid and episodic, as occurs in mud volcanoes, or more gradual and steady, as occurs where the seep orifice is plugged with gas hydrate. In both cases, seep oil and gas appear to rise through the water in close proximity instead of separating. Chemical alteration of the oil is relatively minor during transit through the water column, but once at the sea surface its more volatile components rapidly evaporate. Gas bubbles rapidly dissolve as they rise, although observations suggest that oil coatings on the bubbles inhibit dissolution. At the sea surface, the floating oil forms slicks, detectable by remote sensing, whose origins are laterally within ,1000 m of the seafloor vent. This contradicts the much larger distance predicted if oil drops rise through a 500 m water column at an expected rate of ,0.01 m s,1 while subjected to lateral currents of ,0.2 m s,1 or greater. It indicates that oil rises with the gas bubbles at speeds of ,0.15 m s,1 all the way to the surface. [source] Central Bank Accountability and Transparency: Theory and Some EvidenceINTERNATIONAL FINANCE, Issue 1 2002Sylvester C. W. Eijffinger The first part of this paper outlines the concept of democratic accountability of central banks, and compares the legal accountability of the European Central Bank (ECB) with some other central banks (Bank of Canada, Bank of Japan, Bank of England and the Federal Reserve System). The second part presents a theory of central bank accountability. Two aspects of accountability are considered: transparency of actual monetary policy and the question of who bears final responsibility for monetary policy. The paper shows that accountability through transparency leads to a lower expected rate of inflation and less stabilization of supply shocks. Accountability through shifting final responsibility in the direction of the government leads to higher inflationary expectations and more stabilization of supply shocks. [source] Effect of Analysts' Optimism on Estimates of the Expected Rate of Return Implied by Earnings ForecastsJOURNAL OF ACCOUNTING RESEARCH, Issue 5 2007PETER D. EASTON ABSTRACT Recent literature has used analysts' earnings forecasts, which are known to be optimistic, to estimate implied expected rates of return, yielding upwardly biased estimates. We estimate that the bias, computed as the difference between the estimates of the implied expected rate of return based on analysts' earnings forecasts and estimates based on current earnings realizations, is 2.84%. The importance of this bias is illustrated by the fact that several extant studies estimate an equity premium in the vicinity of 3%, which would be eliminated by the removal of the bias. We illustrate the point that cross-sample differences in the bias may lead to the erroneous conclusion that cost of capital differs across these samples by showing that analysts' optimism, and hence, bias in the implied estimates of the expected rate of return, differs with firm size and with analysts' recommendation. As an important aside, we show that the bias in a value-weighted estimate of the implied equity premium is 1.60% and that the unbiased value-weighted estimate of this premium is 4.43%. [source] Use of Forecasts of Earnings to Estimate and Compare Cost of Capital Across RegimesJOURNAL OF BUSINESS FINANCE & ACCOUNTING, Issue 3-4 2006Article first published online: 19 MAY 200, Peter Easton Abstract: I critically examine several of the methods used in the recent literature to estimate and compare the cost of capital across different accounting/regulatory regimes. I focus on the central importance of expectations of growth beyond the short period for which forecasts of future pay-offs (dividends and/or earnings) are available. I illustrate, using the stocks that comprised the Dow Jones Industrial Average (DJIA) at December 31, 2004, as an example, the differences between the growth rates implied by the data, and growth rates that are often assumed in the literature. My analyses show that assumptions about growth beyond the (short) forecast horizon may seriously affect the estimates of the expected rate of return and may lead to spurious inferences. [source] Impaired sexual behavior in male mice deficient for the ,1,3 N -Acetylglucosaminyltransferase-I geneMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 5 2008Franziska Biellmann Abstract The ,1,3 N -acetylglucosaminyltransferase-1 (B3gnt1) gene encodes a poly- N -acetyllactosamine synthase which can initiate and extend poly- N -acetyllactosamine chains [Gal(,1,4)GlcNAc (,1,3)n]. Previous investigations with heterozygous and homozygous null mice for this gene have revealed the importance of poly- N -acetyllactosamine chains for the formation of olfactory axon connections with the olfactory bulb and the migration of gonadotropin releasing hormone neurons to the hypothalamus. The possible long-term effects of these developmental defects, however, has not yet been studied. Here we have examined a reproductive phenotype observed in B3gnt1 -null mice. Whereas the B3gnt1 null females were fertile, the B3gnt1 null males were not able to sire litters at the expected rate when mated to either wildtype or B3gnt1 -null females. We assessed male sexual behavior as well as male reproduction parameters such as testes size, spermatogenesis, sperm number, morphology, and the development of early embryos in order to identify the source of a reduced rate of reproduction. Our findings show that the B3gnt1 null male reproductive organs were functional and could not account for the lower rate at which they produced offspring with wildtype conspecifics. Hence, we propose that the phenotype observed resulted from an impaired sexual response to female mating partners. Mol. Reprod. Dev. 75: 699,706, 2008. © 2007 Wiley-Liss, Inc. [source] Postmarketing surveillance of medications and pregnancy outcomes: Clarithromycin and birth malformations,PHARMACOEPIDEMIOLOGY AND DRUG SAFETY, Issue 7 2000Carol R. Drinkard MPh PhD Abstract Purpose This retrospective surveillance study used linked administrative claims data and medical records to determine the rate and types of birth malformations in infants born to women exposed to the antibiotic, clarithromycin (Biaxin®), during the first trimester of pregnancy. Methods Pharmacy and hospital claims from eight geographically diverse health plans were used to identify women who had a delivery claim within 270 days of a clarithromycin prescription over a 5-year period (1991,1995). Hospital delivery admission medical records for 143 mothers and their 149 infants were abstracted to identify birth malformations. Results Five infants were identified with major malformations, three with minor malformations, and four with undescended testicles likely to resolve with time. The observed rate of 3.4% (95% CI, 0.5, 6.3) for major malformations was not statistically significantly different compared to an expected rate of 2.8% based on earlier national data. There was no consistency across types of major malformations. Conclusions These results provide no evidence that clarithromycin is a likely major teratogen in humans. Use of claims data is one way to evaluate quickly and efficiently the safety of prescription medications in humans during pregnancy, especially when both exposure and outcome are rare. Copyright © 2000 John Wiley & Sons, Ltd. [source] Prenatal diagnosis of citrullinemia and argininosuccinic aciduria: evidence for a transmission ratio distortion in citrullinemiaPRENATAL DIAGNOSIS, Issue 3 2006Wim J. Kleijer Abstract Background In the course of 25 years, we have experienced a high rate of affected fetuses in the prenatal diagnosis of citrullinemia. Methods and Results Ninety-one pregnancies at 1 in 4 risk were tested; 36 were diagnosed as affected (39.5%; P = 0.0015). The high rate of positive diagnoses was found both after chorionic villus sampling (24/68 = 35.3%) and amniocentesis (12/23 = 52.2%) despite the completely different and independent techniques used. Using exactly the same (indirect) enzyme assay for argininosuccinic aciduria on chorionic villi and a similar method on amniotic fluid, the expected rate of affected fetuses was found: 13/53 = 24.5%. Technical and genetic causes for the unexpected results were excluded by confirmatory studies performed on independent fetal material, which was available for 27 of the 36 fetuses affected with citrullinemia. Biochemical confirmation was obtained in the 27 cases, whereas in 18 fetuses homozygosity or compound heterozygosity for disease-causing mutations were retrospectively demonstrated in the stored fetal cells. Conclusion The results suggest the occurrence of preferential transmission of the mutant allele. An explanation for this phenomenon may be found in a protective role of argininosuccinic acid synthetase deficiency in mutant sperm cells against the possibly detrimental or apoptotic effect of nitric oxide produced normally from arginine by nitric oxide synthase. Copyright © 2006 John Wiley & Sons, Ltd. [source] Semi-geostrophic solutions for flow over a ridgeTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 623 2007M. J. P. Cullen Abstract An algorithm for solving the semi-geostrophic (SG) equations using real physical variables in terrain-following coordinates is developed and used to demonstrate the expected rate of convergence of solutions of the complete equations of motion to SG solutions as the Rossby number is reduced. The tests are carried out with significant orography in a vertical slice geometry. Two asymptotic limits are tested. The SG limit is singular in one of the limits and smooth in the other. The results show the validity of using the SG model for diagnostic purposes in appropriate regimes. They also expose a number of boundary condition and numerical issues, showing that comparison with rigorous error estimates is a useful way of validating numerical procedures. © Crown Copyright 2007. Reproduced with the permission of the Controller of HMSO. Published by John Wiley & Sons, Ltd [source] Cancer Mortality in Kidney TransplantationAMERICAN JOURNAL OF TRANSPLANTATION, Issue 8 2009B. A. Kiberd Immunosuppression is associated with an increased risk of cancer in kidney transplant recipients compared to the general population. It is less clear whether standardized cancer mortality ratios (SMRs) are also increased. This study's hypothesis is that SMRs are not increased because of competing risks of death. During the median follow-up of 5.05 years (Q1,Q3: 2.36,8.62), there were 1937 cancer deaths and 36 619 noncancer deaths among 164 078 first kidney-only transplant recipients captured in the United States Renal Data System between January 1990 and December 2004. The observed cancer death rate was 206 per 100 000 patient-years compared to an expected rate of 215 per 100 000 patient-years in the general population. The overall age- and sex-adjusted SMR was only 0.96 (95% CI 0.92,1.00). However, patients <50 years had SMRs significantly greater than unity while patients >60 had SMRs lower than unity. Up to 25% of cancer-related deaths occurred after allograft failure. These findings challenge the notion that cancer is a major cause of premature death in all kidney transplant recipients and has implications for design of cancer prevention strategies in kidney transplant recipients. [source] Alemtuzumab Induction and Sirolimus Plus Mycophenolate Mofetil Maintenance for CNI and Steroid-Free Kidney Transplant ImmunosuppressionAMERICAN JOURNAL OF TRANSPLANTATION, Issue 12 2005S. M. Flechner We performed a pilot study in which 22 kidney recipients (14 LD: 8 DCD) were given alemtuzumab induction (30 mg day 0 and 1), steroids (500 mg mp day 0 and 1, none thereafter), mycophenolate mofetil (MMF) maintenance (500 mg b.i.d) and sirolimus (concentration controlled 8,12 ng/mL). With a mean follow-up of 15.9 months, patient survival is (21/22) 96% and graft survival (19/22) 87%. Acute rejections occurred in (8) 36.3% (two humoral). Of 19 surviving grafts, 18 (95%) remain steroid and 15 (79%) CNI-free. At 1 year, mean creatinine was 1.43 mg/dL. Overall infection rates were low, but 2 patients developed severe acute respiratory distress syndrome (ARDS) at month 3 and 7, respectively, resulting in mortality in one and a graft loss in the other. No cancer or PTLD was observed. Leukopenia was common and MMF dose was reduced or eliminated in 6/22 (27%) patients. The reported higher than expected rate of acute rejection, leukopenia and possible pulmonary toxicity suggests excessive morbidity. Modifications such as an initial period of CNI use should be considered. [source] The total median in statistical quality controlAPPLIED STOCHASTIC MODELS IN BUSINESS AND INDUSTRY, Issue 4 2004Fernanda Figueiredo Abstract In industry, most of the process observations are assumed to come from a normal population, but usually we merely want to control the process mean value. It is thus sensible to find control statistics, which are ,robust' to monitor the process mean, giving the expected rate of false alarms whenever that mean is close to the target value, although not under a normal regime. Simulation studies for a few symmetric and asymmetric distributions allow us to suggest the total median as a robust median estimator. We shall here analyse such a robustness, as well as the robustness of the total median chart comparatively to the sample mean chart, whenever we want to control the mean value of a symmetric underlying parent. Some indication is also provided on the comparative out-of-control behaviour of the two charts. Copyright © 2004 John Wiley & Sons, Ltd. [source] Trends in incidence and mortality in rheumatoid arthritis in Rochester, Minnesota, over a forty-year periodARTHRITIS & RHEUMATISM, Issue 3 2002Michele F. Doran Objective To determine time trends in the epidemiology of rheumatoid arthritis (RA) in a population-based cohort. Methods An inception cohort of residents of Rochester, Minnesota ,18 years of age who first fulfilled the American College of Rheumatology 1987 criteria between January 1, 1955 and December 31, 1994 (applied retrospectively, as appropriate) was assembled and followed up until January 1, 2000. Incidence rates were estimated and were age- and sex-adjusted to the 1990 white population of the US. A birth cohort analysis was performed, and survival rates over time were examined. Results The incidence cohort comprised 609 patients, 445 (73.1%) of whom were female and 164 (26.9%) were male, with a mean age at incidence of 58.0 years. The overall age- and sex-adjusted annual incidence of RA among Rochester, Minnesota, residents ,18 years of age was 44.6/100,000 population (95% confidence interval 41.0,48.2). While the incidence rate fell progressively over the 4 decades of study, from 61.2/100,000 in 1955,1964, to 32.7/100,000 in 1985,1994, there were indications of cyclical trends over time. Birth cohort analysis showed diminishing incidence rates through successive cohorts following a peak in the 1880,1890 cohorts. Incidence rates increased with age until age 85, but peaked earlier in women than in men. The survival rate in RA patients was significantly lower than the expected rate in the general population (P < 0.001), and no improvement was noted over time. Conclusion The secular trends demonstrated in this study population, including the progressive decline in the incidence of RA over the last 40 years, suggest that an environmental factor may play a role in the etiology of RA. [source] Bacillus Calmette-Guérin therapy in stage Ta/T1 bladder cancer: prognostic factors for time to recurrence and progressionBJU INTERNATIONAL, Issue 7 2004P. Andius OBJECTIVE To report prognostic factors for time to recurrence and progression after bacillus Calmette-Guérin (BCG) prophylaxis in patients with stage Ta/T1 papillary bladder cancer. PATIENTS AND METHODS The clinical records were assessed retrospectively for 236 patients with papillary stage Ta/T1 bladder cancer treated with BCG between 1986 and 2000. Patients with known carcinoma in situ were excluded. The median (range) follow-up was 44 (4,155) months. The effect of 13 variables on the time to recurrence and progression was evaluated using multivariate Cox proportional hazard regression and Kaplan-Meier analyses. RESULTS The recurrence rate was markedly reduced for all grades and stages. Patients with a negative first cystoscopy and maintenance BCG had a significantly longer time to recurrence than those treated with an induction course alone (P < 0.001). Thirty-seven patients (16%) progressed in stage. The result of the first cystoscopy (P < 0.001), tumour grade (P = 0.003) and six or fewer initial instillations (P = 0.002) had prognostic importance for the time to progression. Twenty-eight patients (12%) had a history of an upper tract tumour, which was 3,10 times the expected rate. Age, number of tumours, number of positive cystoscopies, length of tumour history before BCG, BCG strain and treatment year had no influence on time to recurrence and progression. CONCLUSIONS Maintenance treatment does not seem to be necessary among patients with TaG1-G2 disease after a negative first cystoscopy, as the progression rate was very low. One new finding was that BCG seemed to be equally effective among patients with or with no history of an upper tract tumour. Another new and surprising finding was that patients treated with fewer than six induction instillations, because of very bothersome side-effects, had an increased risk of tumour progression and of local failure. [source] In Vitro and In Silico Analysis of Annexin V Binding to Lymphocytes as a Biomarker in Emergency Department Sepsis StudiesACADEMIC EMERGENCY MEDICINE, Issue 9 2007Colin F. Greineder Background: Peripheral blood lymphocyte apoptosis is a recognized feature of serious infection and sepsis and can be easily quantified by flow cytometric measurement of annexin V binding to the cell surface. Use of apoptosis as a biomarker in emergency department (ED) studies of sepsis is potentially difficult because of sample processing requirements and limited availability of a research cytometer with which to measure patient samples. Objectives: To assess, in vitro and in simulation, the relationship between sample stability, timing of patient enrollment, and diagnostic performance of a flow cytometric assay for sepsis in patients evaluated in EDs. Methods: Assuming any clinical trial would require daily sample batching, the authors measured the stability of lymphocyte samples over time, noting the rate at which annexin V,negative cells became positive as ED processing delays increased. With these data, they then optimized a study design that could evaluate lymphocyte apoptosis as a sepsis biomarker by using a series of Monte Carlo,based simulated clinical trials. Results: The authors found that annexin V,negative lymphocytes become positive during storage delays that would be encountered in an ED sepsis trial. The extent of this deterioration was least among cells left as whole blood at room temperature until just before analysis or when lymphocytes were isolated early and stored in culture media at 4°C until analysis. When the expected rate of sample deterioration was considered in simulated clinical trials, an inverse relationship was found between the rate at which patients are enrolled and the best achievable receiver operating characteristic curve a study could produce. Conclusions: Peripheral blood samples being analyzed for lymphocyte apoptosis degrade at a rate relevant to the design of ED trials of sepsis. Because of sample processing delays inherent in studying unscheduled septic patients, the performance of annexin V binding as a biomarker for sepsis can approach, but not be expected to exceed, its performance in a comparable intensive care unit,based study. [source] Effect of Analysts' Optimism on Estimates of the Expected Rate of Return Implied by Earnings ForecastsJOURNAL OF ACCOUNTING RESEARCH, Issue 5 2007PETER D. EASTON ABSTRACT Recent literature has used analysts' earnings forecasts, which are known to be optimistic, to estimate implied expected rates of return, yielding upwardly biased estimates. We estimate that the bias, computed as the difference between the estimates of the implied expected rate of return based on analysts' earnings forecasts and estimates based on current earnings realizations, is 2.84%. The importance of this bias is illustrated by the fact that several extant studies estimate an equity premium in the vicinity of 3%, which would be eliminated by the removal of the bias. We illustrate the point that cross-sample differences in the bias may lead to the erroneous conclusion that cost of capital differs across these samples by showing that analysts' optimism, and hence, bias in the implied estimates of the expected rate of return, differs with firm size and with analysts' recommendation. As an important aside, we show that the bias in a value-weighted estimate of the implied equity premium is 1.60% and that the unbiased value-weighted estimate of this premium is 4.43%. [source] Wage Expectations: A Comparison of Swiss and US StudentsKYKLOS INTERNATIONAL REVIEW OF SOCIAL SCIENCES, Issue 1 2000Stefan C. Wolter Wage expectations can play a significant role in a variety of economic areas. This study analyses the wage expectations of students who are on the verge of making a decision concerning their educational path or who have already reached such a decision. Since each student in our study has been asked to discuss expectations in relation to various educational scenarios, this data can be used to check certain human capital theory assumptions. It is possible to ascertain the wage effects which students expect from certain educational decisions. Moreover it is possible to assess the expected rates of return on education without asking the students directly. The results of this study make it clear that both in the USA and in Switzerland the wage expectations of students do not differ significantly from the cross-sectional labor market data, despite considerable heterogeneity in some cases. [source] PHYSIOLOGICAL AND BEHAVIORAL DEVELOPMENT IN DELPHINID CALVES: IMPLICATIONS FOR CALF SEPARATION AND MORTALITY DUE TO TUNA PURSE-SEINE SETSMARINE MAMMAL SCIENCE, Issue 1 2007Shawn R. Noren Abstract Tuna purse-seiners in the eastern tropical Pacific (ETP) capture yellowfin tuna by chasing and encircling herds of associated dolphins. This fishery has caused mortality in 14 dolphin species (20 stocks) and has led to significant depletions of at least three stocks. Although observed dolphin mortality is currently low, set frequency remains high and dolphin stocks are not recovering at expected rates. Mortality of nursing calves permanently separated from their mothers during fishery operations may be an important factor in the lack of population recovery, based on the recent discovery that calves do not accompany 75%,95% of lactating females killed in the purse-seine nets. We assessed age-specific potential for mother,calf separations and subsequent mortality of calves by reviewing and synthesizing published data on physiological and behavioral development in delphinids from birth through 3 yr postpartum. Results indicate that evasive behavior of mothers, coupled with the developmental state of calves, provides a plausible mechanism for set-related mother,calf separations and subsequent mortality of calves. Potential for set-related separation and subsequent mortality is highest for 0,12-mo-old dolphins and becomes progressively lower with age as immature dolphins approach adult stamina and attain independence. [source] Attention-Deficit/Hyperactivity Disorder (ADHD) and Binge EatingNUTRITION REVIEWS, Issue 9 2007Samuele Cortese MD Attention-deficit/hyperactivity disorder (ADHD) is characterized by a persistent and pervasive pattern of inattention and/or hyperactivity-impulsivity. Emerging data suggest higher than expected rates of binge eating occur in subjects with ADHD. Several hypotheses may explain this newly described comorbidity: 1) inattention and/or impulsivity foster binge eating, 2) ADHD and binge eating share common neurobiolog-ical bases, 3) binge eating contributes to ADHD, or 4) psychopathological factors common to both binge eating and ADHD mediate the association. In patients with ADHD and binge eating, both conditions might benefit from common therapeutic strategies. Further research is needed to gain insight into the association between ADHD and binge eating in order to facilitate more appropriate clinical management and, ultimately, a better quality of life for patients with both conditions. [source] Agreement between GPRD smoking data: a survey of general practitioners and a population-based survey,PHARMACOEPIDEMIOLOGY AND DRUG SAFETY, Issue 7 2004James D. Lewis MD, MSCE Abstract Background Cigarette smoking is a common habit that is associated with many diseases. Smoking is often an important confounding variable in pharmacoepidemiological studies. The General Practice Research Database (GPRD) is widely used in pharmacoepidemiological research. In this study, we compare data recorded in the GPRD with the smoking history obtained from direct query of general practitioners (GPs) and from a population-based survey. Methods We completed a mailed survey of GPs caring for a random sample of 150 patients with inflammatory bowel disease. The survey asked the GP to categorize the patients smoking status on a specified date. These results were then compared to the data recorded in the GPRD. Smoking status of 225,308 randomly selected GPRD patients without inflammatory bowel disease was compared to the results of a population-based household survey. Results Completed surveys with usable data were received from GPs on 136 of the 150 patients (91%). The sensitivity and positive predictive value of the database for current smoking were 78% (95%,CI: 52,94) and 70% (95%,CI: 46,88) respectively. The sensitivity and positive predictive value of former smoking were 53% (95%,CI: 28,77) and 60% (95%,CI: 32,84) respectively. Current and former smoking rates in the GPRD were 79% and 29% respectively of expected rates according to the population-based survey . Conclusions Current smoking is more completely recorded in the GPRD than former smoking. These data need to be considered when planning GPRD studies where smoking is an important exposure variable. Copyright © 2003 John Wiley & Sons, Ltd. [source] Effect of Comorbidity Adjustment on CMS Criteria for Kidney Transplant Center PerformanceAMERICAN JOURNAL OF TRANSPLANTATION, Issue 3 2009E. D. Weinhandl The Centers for Medicare & Medicaid Services (CMS) uses kidney transplant outcomes, unadjusted for standard comorbidity, to identify centers with sufficiently higher than expected rates of graft failure or patient death (underperforming centers) that they may be denied Medicare participation. To examine whether comorbidity adjustment would affect this determination, we identified centers that would have failed to meet 1-year graft survival criteria, 1992,2005, with and without adjustment using the Elixhauser Comorbidity Index. Adjustment was performed for each U.S. center for 24 consecutive (overlapping) 30-month intervals, including 102 176 adult deceased-donor and living-donor kidney transplant patients with Medicare as primary payer 6 months pretransplant. For each interval, we determined percent positive agreement (PPA) (number of centers underperforming both before and after adjustment, divided by number underperforming either before or after adjustment). Overall PPA was 80.8%, with no evidence of a trend over time. Among deceased-donor recipients, 10 of 31 comorbid conditions were predictors of graft failure in at least half of the intervals, as were six conditions among living-donor recipients. Lack of comorbidity adjustment may disadvantage centers willing to accept higher risk patients. Risk of jeopardizing Medicare funding may give centers incentive to deny transplantation to higher risk patients. [source] Use, misuse and extensions of "ideal gas" models of animal encounterBIOLOGICAL REVIEWS, Issue 3 2007John M. C. Hutchinson Abstract Biologists have repeatedly rediscovered classical models from physics predicting collision rates in an ideal gas. These models, and their two-dimensional analogues, have been used to predict rates and durations of encounters among animals or social groups that move randomly and independently, given population density, velocity, and distance at which an encounter occurs. They have helped to separate cases of mixed-species association based on behavioural attraction from those that simply reflect high population densities, and to detect cases of attraction or avoidance among conspecifics. They have been used to estimate the impact of population density, speeds of movement and size on rates of encounter between members of the opposite sex, between gametes, between predators and prey, and between observers and the individuals that they are counting. One limitation of published models has been that they predict rates of encounter, but give no means of determining whether observations differ significantly from predictions. Another uncertainty is the robustness of the predictions when animal movements deviate from the model's assumptions in specific, biologically relevant ways. Here, we review applications of the ideal gas model, derive extensions of the model to cover some more realistic movement patterns, correct several errors that have arisen in the literature, and show how to generate confidence limits for expected rates of encounter among independently moving individuals. We illustrate these results using data from mangabey monkeys originally used along with the ideal gas model to argue that groups avoid each other. Although agent-based simulations provide a more flexible alternative approach, the ideal gas model remains both a valuable null model and a useful, less onerous, approximation to biological reality. [source] | ||||||||||||||||||||||