Stephan Arndt

A general uncertainty analysis is applied to chordal, transit time ultrasonic flow meters that are used in nuclear power plant feedwater loops. This investigation focuses on relationships between the major parameters of the flow measurement. For this study, mass flow rate is divided into three components, profile factor, density, and a form of volumetric flow rate. All system parameters are used to calculate values for these three components. Uncertainty is analyzed using a perturbation method. Sensitivity coefficients for major system parameters are shown, and these coefficients are applicable to a range of ultrasonic flow meters used in similar applications. Also shown is the uncertainty to be expected for density along with its relationship to other system uncertainties. One other conclusion is that pipe diameter sensitivity coefficients may be a function of the calibration technique used. (authors)

Objective— We previously reported preliminary data (N=14) demonstrating a significant and positive relationship between forearm vascular function and neuropsychological performance in individuals with atherosclerotic vascular disease (AVD). The current study was conducted to confirm and extend those findings in a much larger, nonoverlapping sample. Methods and Results— Participants were 82 individuals with AVD, with no history of stroke, cardiac surgery, or dementia. Forearm vascular function was measured before and after brachial artery infusion of vasoactive agents (acetylcholine, nitroprusside, verapamil). Neuropsychological functioning was assessed with the Repeatable Battery for the Assessment of Neuropsychological Status. Statistical analysis included multiple regression and partial correlations, controlling for education. Vascular function was significantly and positively associated with neuropsychological performance [R 2 change=0.116, F change (3,74)=3.72, P =0.015]. Follow...

... References 1. Alsobrook JP II, Pauls DL: A factor analysis of tic symptoms in Gilles de la Tourette's syndrome. ... Arch Gen Psychiatry 2001; 58: 959–964 REBECCA FULLER, PH.D. PEG NOPOULOS, MD STEPHAN ARNDT, PH.D. DAN O'LEARY, PH.D. BENG-CHOON HO, MRCP ...

To assess nurses' views of a nursing model in which nurses screen and also treat new mothers who exhibit symptoms of depression. This is Part 1 of this descriptive survey (Part 2 in MCN 35(5)), in which nurses (n = 520) completed a statewide survey assessing nurses' views of a model of nursing care that both screens and treats postpartum depression. The majority "strongly agreed" or "agreed" with the statement "having nurses screen for depression using a brief screening tool is a good idea." Most (67.1%) chose the Ob-Gyn Clinic as the appropriate site for such screening. Regarding treatment by nurses, the vast majority of nurses (93.7%) "agreed" or "strongly agreed" with the statement "nurse-delivered counseling with mildly depressed women is a good idea." Almost one half of the nurses already regularly provided some form of counseling, and approximately three quarters were willing to participate in a counseling skills training program. Less than 1.0% (n = 3) indicated that nurse-delivered counseling should not be implemented. The most frequently chosen setting for a nurse-delivered counseling program was home visits (70.6%, n = 367). Our results indicate nurse-delivered screening and treatment of postpartum women is overwhelmingly supported by this segment of U.S. nursing professionals, and indeed, is already occurring in many instances. Nurses who have frequent contact with women during the perinatal period are well positioned to provide screening and treatment for postpartum depression. To implement the two-part U.K. model (both screening and treatment), it is necessary to develop educational programs for staff and patients, and establish screening and treatment protocols as well as referral resources for those with such a need.

ABSTRACT a b s t r a c t The Markov/cell-to-cell mapping technique (CCMT) and the dynamic flowgraph methodology (DFM) are two system logic modeling methodologies that have been proposed to address the dynamic characteristics of digital instrumentation and control (I&C) systems and provide risk-analytical capabilities that supplement those provided by traditional probabilistic risk assessment (PRA) techniques for nuclear power plants. Both methodologies utilize a discrete state, multi-valued logic representation of the digital I&C system. For probabilistic quantification purposes, both techniques require the estimation of the probabilities of basic system failure modes, including digital I&C software failure modes, that appear in the prime implicants identified as contributors to a given system event of interest. As in any other system modeling process, the accuracy and predictive value of the models produced by the two techniques, depend not only on the intrinsic features of the modeling paradigm, but also and to a considerable extent on information and knowledge available to the analyst, concerning the system behavior and operation rules under normal and off-nominal conditions, and the associated controlled/monitored process dynamics. The application of the two methodologies is illustrated using a digital feedwater control system (DFWCS) similar to that of an operating pressurized water reactor. This application was carried out to demonstrate how the use of either technique, or both, can facilitate the updating of an existing nuclear power plant PRA model following an upgrade of the instrumentation and control system from analog to digital. Because of scope limitations, the focus of the demonstration of the methodologies was intentionally limited to aspects of digital I&C system behavior for which probabilistic data was on hand or could be generated within the existing project bounds of time and resources. The data used in the probabilistic quantification portion of the process were gathered partially from fault injection experiments with the DFWCS, separately conducted under conservative assumptions, partially from operating experience, and partially from generic data bases. The purpose of the quantification portion of the process was, purely to demonstrate the PRA-updating use and application of the methodologies, without making any particular claim regarding the specific validity and predictive value of the data utilized to illustrate the quantitative risk calculations produced from the qualitative information analytically generated by the models. A comparison of the results obtained from the Markov/CCMT and DFM regarding the event sequences leading to DFWCS failure modes show qualitative and quantitative consistency for the risk scenarios and sequences under consideration. The study also shows that: (a) the risk significance of the timing of system component failures may depend on factors that include the actual variability of initiating conditions of a dynamic transient, even within the nominal control range and (b) the range of dynamic outcomes may also be dependent on the choice of the assumed basic system-component failure modes included in the models, regardless of whether some of these would or would not be considered to have direct safety implications according to the traditional safety/non-safety equipment classifications.

Address: 1School of Environment and Development, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK, 2School of Health and Social Care, Oxford Brookes University, Jack Straws Lane, Marston, Oxford, OX3 0FL, UK and 3Centre for Drug Misuse ...

Address: 1School of Environment and Development, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK, 2School of Health and Social Care, Oxford Brookes University, Jack Straws Lane, Marston, Oxford, OX3 0FL, UK and 3Centre for Drug Misuse ...

Early stages of chronic obstructive pulmonary disease (COPD) are characterized by the loss and narrowing of terminal bronchioles in the lung resulting in 'air-trapping,' often occurring before overt emphysema manifests. Individuals with an airway-predominant phenotype of COPD display extensive lung air-trapping and are at greater cardiovascular disease (CVD) risk than COPD patients with an emphysema-predominant phenotype. We hypothesized that the degree of computed tomography (CT)-quantified lung air-trapping would be associated with greater aortic and carotid artery stiffness and lower endothelial function, known biomarkers of CVD risk. Lung air-trapping was associated with greater aortic stiffness (carotid femoral pulse wave velocity, CFPWV) (r=0.60, p=0.007) and carotid β-stiffness (r=0.75, p=0.0001) among adults with (n=10) and without (n=9) a clinical diagnosis of COPD and remained significant after adjusting for blood pressure (BP) and smoking history (pack-years) (car...

Recent changes in marijuana policies and their potential negative effects on youth development are a public health concern. Identifying the most appropriate treatment approaches for problematic marijuana use is important. The aim of this study was to track marijuana use among young people by examining national changes from 1995 to 2012 in the demographics, referral sources, and the substance use patterns related to youth admissions to substance abuse treatment programs. We examined first-time substance abuse treatment admissions among youth, utilizing the Treatment Episode Data Set - Admissions (TEDS-A) of the Substance Abuse Mental Health Services Administration (N = 12,025,787). Chi-squared analysis was used to examine differences between admission years and binomial logistic regression was used to examine trends over the 18 years. We found increasing numbers of youth in dependent living situations (e.g. with parents) admitted to substance use disorder treatment for marijuana. We ...

There are several methods for building prediction models. The wealth of currently available modeling techniques usually forces the researcher to judge, a priori, what will likely be the best method. Super learning (SL) is a methodology that facilitates this decision by combining all identified prediction algorithms pertinent for a particular prediction problem. SL generates a final model that is at least as good as any of the other models considered for predicting the outcome. The overarching aim of this work is to introduce SL to analysts and practitioners. This work compares the performance of logistic regression, penalized regression, random forests, deep learning neural networks, and SL to predict successful substance use disorders (SUD) treatment. A nationwide database including 99,013 SUD treatment patients was used. All algorithms were evaluated using the area under the receiver operating characteristic curve (AUC) in a test sample that was not included in the training sample...

Previous data suggest the possibility that haloperidol daily dosing requirements may be confounded by smoking and, at higher doses, capacity-limited metabolism. Forty hospitalized patients suffering from an acute exacerbation of schizophrenia were treated for 2 weeks with fixed oral doses of haloperidol ranging from 10 to 70 mg/day (0.13 to 0.95 mg/kg/day) that produced mean steady-state concentrations between 4.5 and 55.4 ng/ml. No significant differences between the smoking and nonsmoking groups were obvious for the factors of weight, age, sex, daily doses, steady-state clearance, and steady-state haloperidol concentrations in plasma at week 1, week 2, and their mean. The hypothesis that the relationship between haloperidol dose and steady-state haloperidol concentration in plasma was affected by patients' smoking status and metabolic capacity was tested by multiple linear regression analysis and initially rejected. The relationship of dose to haloperidol concentration was fitted as a linear function. To improve the curve fit, the haloperidol concentrations and doses were transformed to their natural logs and then the regression line was refitted. The multiple regression analysis was repeated with the data in their transformed state. It was found that, although smoking status and dose of the drug did not independently affect the average haloperidol concentration, together they interacted in such a way that individual haloperidol concentrations were dependent on the smoking status at specific doses. Thus, two haloperidol dosing equations were generated, one for smokers and one for nonsmokers.

Background: Numerous case reports have linked cloza- pine to the development of diabetes mellitus and hyper- lipidemia in patients with schizophrenia. However, in- vestigators have been unable to clearly demonstrate this association when compared with a control group receiv- ing conventional antipsychotics. Methods: Medical and pharmacy claims from the Iowa Medicaid program were used to compare incidence rates for diabetes,

Knowledge of the relationship between specific cognitive abnormalities and the clinical symptoms of schizophrenia could give insight into the nature of their underlying pathophysiology. Composite scores were generated for negative, disorganized, and psychotic symptom ratings in 134 patients with schizophrenia (DSM-IV criteria). Partial correlations (each composite corrected for the others) were computed with neuropsychological measures. Negative symptoms were related to poor performance on tests of verbal learning and memory, verbal fluency, visual memory, and visual-motor sequencing. Disorganized symptoms were correlated with lower verbal IQ and poor concept attainment. Psychotic symptoms had no significant relationship with cognitive deficit.

Positron emission tomography ([(15)O] water PET) was used to examine the relationship between age and regional cerebral blood flow (rCBF) in schizophrenia. Forty-nine unmedicated male patients, ages 20-51, underwent imaging during an eyes-closed resting condition. Negative correlations were observed between age and rCBF in the anterior cingulate, as well as in frontal (Brodmann area 8) and parietal cortex (area 40) bilaterally. The observation of reduced rCBF in the anterior cingulate with increased age is consistent with previous findings in healthy subjects. In contrast, the reduced flow observed in the frontal and parietal regions may be unique to schizophrenia.

This study explored the association between psychosocial variables and symptoms among patients with schizophrenia-spectrum disorders who have attempted suicide and those who have not attempted suicide. Of 336 patients with a DSM-III-R diagnosis of schizophrenia or schizoaffective disorder who were consecutively evaluated at a university-affiliated clinical research center, 98, or 29.2 percent, reported one or more suicide attempts. Compared with patients who had not attempted suicide, patients who had made an attempt had a greater number of lifetime depressive episodes, an earlier age of onset of their illness, and an earlier age at first hospitalization.

The influence of psychiatric symptoms and cognitive impairment on daily living skills was explored in a series of nursing home residents. Three categories of symptoms were examined: behavioral disturbances, depression, and delusions. Nursing home residents (N=69) underwent comprehensive psychiatric evaluations. Relationships among psychiatric symptoms, cognitive function, and daily living skills were assessed by using regression and correlation analyses. Cognitive decline had the greatest effect on functional impairment in a standard least squares model, followed by behavioral disturbances. Psychiatric symptoms correlated positively with each other and with functional impairment, and correlated inversely with cognitive functioning. Cognitive decline appears to confer the greatest burden of functional disability in the nursing home setting. After cognitive effects were accounted for, behavioral dysregulation was also associated with functional impairment. In conclusion, interventions to enhance cognition and ameliorate behavioral disturbances are important areas for future studies in long-term care.

To determine whether abnormalities of impulse control persist across the course of bipolar disorder, thereby representing potential state markers and endophenotypes. Impulse control of 108 bipolar I manic or mixed patients was measured on three tasks designed to study response inhibition, ability to delay gratification, and attention; namely, a stop signal task, a delayed reward task, and a continuous performance task, respectively. Barrett Impulsivity Scale (BIS-11) scores were also obtained. Patients were then followed for up to one year and reassessed with the same measures if they developed depression or euthymia. Healthy comparison subjects were also assessed with the same instruments on two occasions to assess measurement stability. At baseline, bipolar subjects demonstrated significant deficits on all three tasks as compared to healthy subjects, consistent with more impulsive responding in the bipolar manic/mixed group. In general, performance on the three behavioral tasks normalized upon switching to depression or developing euthymia. In contrast, BIS-11 scores were elevated during mania and remained elevated as bipolar subjects developed depression or achieved euthymia. Bipolar I disorder patients demonstrate deficits on laboratory tests of various aspects of impulsivity when manic, as compared to healthy subjects, that largely normalize with recovery and switching into depression. However, elevated BIS-11 scores persist across phases of illness. These findings suggest that impulsivity has both affective-state dependent and trait components in bipolar disorder.

For many years, it has been assumed that medications affect brain chemistry and physiology but not structure. Recent reports suggest that neuroleptic medication changes basal ganglia volume. To explore this possibility, the authors assessed for basal ganglia volume change in individuals who had their basal ganglia structures delineated and measured on magnetic resonance scans at the beginning and end of a 2-year period and who received neuroleptic medication during this time. The basal ganglia volumes of 23 male patients with schizophrenia spectrum disorders were measured from manual traces delineating the caudate and lenticular nucleus on magnetic resonance images at admission and 2 years later. Patients' neuroleptic exposure was calculated over the 2 years by using a dose-year formula. During the 2-year period, mean basal ganglia volume of patients receiving predominantly typical neuroleptics increased, while the opposite was observed for patients receiving mostly atypical neuroleptics. Correlation analysis for the entire group showed a positive relationship between the 2-year exposure to typical neuroleptic medication and change in basal ganglia volume and the reverse for exposure to atypical neuroleptics. In this group, basal ganglia volume increased following exposure to typical neuroleptics and decreased following exposure to atypical neuroleptics.

The effect of physiologic (100 mg/wk) and supraphysiologic (250 and 500 mg/wk) doses of testosterone cypionate (TC) on automobile driving were studied using the Iowa Driver Simulator. Six normal subject volunteers were studied off TC and on TC once steady-state concentrations were achieved after at least three weeks of dosing. Despite the administration of supraphysiologic testosterone doses, an increase in aggressive driving behavior was not detected. Likewise, corresponding psychometric testing using the Buss-Durkee Hostility Inventory to assess aggression was unable to detect any change in aggression in the test subjects. Although aggressive driving behavior may be increased by testosterone administration, the drug itself may not be responsible for these effects. Supraphysiologic doses greater than 500 mg/wk and a semi-controlled research environment may be necessary to produce this effect since case reports of AAS abuse causing altered driving behavior may be multifactorial in nature.

This study evaluated the longitudinal course of neuropsychological deficits in a group of patients with new or recent onset schizophrenia. Thirty-five inpatients with DSM-III-R diagnoses of schizophrenia were administered a comprehensive battery of neuropsychological tests during their index hospitalization, and either 1 or 2 years after intake. Cognitive function remained stable in most domains, including motor speed, verbal and nonverbal memory, and verbal learning. Significant improvement in neuropsychological performance was observed on a task of complex attention (Trails B) and a set response shifting task (Stroop). These improvements were correlated with changes in clinical symptoms, but not with changes in medication dose. These findings suggest that most of the neuropsychological functioning in schizophrenia is stable over the first few years of the illness. Moreover, those neuropsychological deficits that remain unchanging appear to be independent of significant change in clinical symptoms, suggesting they may be a trait of the illness. However, a small subset of functions such as complex attention and response inhibition appear to fluctuate with time, and in particular, with clinical symptomatology, and may be considered 'state' dependent.

In the treatment of attention-deficit hyperactivity disorder (ADHD), the efficacy of the tricyclic antidepressants and monoamine oxidase inhibitor antidepressants has been compared with that of both placebo and the stimulants (methylphenidate and/or dextroamphetamine). However, the effectiveness of bupropion has been contrasted only with placebo. The primary aim of this study was to contrast the efficacy of bupropion with that of methylphenidate in the treatment of ADHD. A double-blind, crossover design was used in this study. After a 14-day medication washout period, 15 ADHD subjects (7 to 17 years old) were randomized to either methylphenidate or bupropion for 6 weeks, washed out for an additional 2 weeks, and then "crossed over" to the other drug. Methylphenidate was titrated to the maximum effective dose of 0.4 to 1.3 mg/kg per day (mean 0.7 mg/kg per day) and bupropion was titrated to an effective dose ranging from 1.4 to 5.7 mg/kg per day (mean 3.3 mg/kg per day). Both methylphenidate and bupropion produced significantly greater (p < .001) and equivalent improvement on the Iowa-Conners Teacher's Rating Scale according to both the subjects' parents and teachers. The same pattern of improvement was also noted for improvement on the Clinical Global Impression Scale, Kagan's Matching Familiar Figures Test, Continuous Performance Test, Children's Depression Inventory, Children's Manifest Anxiety Scale, and Rey Auditory-Verbal Learning Test. In this double-blind, crossover trial, bupropion and methylphenidate were both effective and did not differ in their overall efficacy as treatments for ADHD.

This study examines the relationship between functional impairment and depression in patients with heart failure using a new measure of Attitudes about Impairment. Sixty-nine patients with chronic heart failure completed diagnostic interviews and questionnaires about mood, comorbid illness, functional impairment, and social support. Study design was case-control with cases selected because they met criteria for DSM-IV major or minor depression (n = 23). Controls reported no or very few depressive symptoms (n = 46). A preliminary study of the psychometric properties of a new 15-item measure of Attitudes about Impairment was conducted. The Attitudes about Impairment measure had a Cronbach's alpha = 0.81. A factor analysis revealed content domains of negative attitudes about dependency, lack of recreational activities, and concerns about being a burden both currently and in the future. This measure correlated highly with the Geriatric Depression Scale (r = 0.61) and remained high even after controlling for medical burden and social support. Patients were diagnosed with either major, minor or no depression using a DSM-IV based structured interview. Depressed patients had significantly more negative attitudes about impairment and the association between depression and physical impairment was no longer significant after controlling for scores on the Attitudes about Impairment measure. Negative attitudes about loss of autonomy, concerns about being a burden and having few recreational activities are strongly associated with depression in patients with heart failure. These attitudes account, in part, for the association between impairment and depression in these patients. The Attitudes about Impairment measure has adequate internal consistency and both convergent and discriminant validity with related measures of social support, functional disability and depression.