3,104 research outputs found

    Selected factors in assessment of a group designated as school malperformers

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    This project was an exploratory study of malperformance among 60 children of the seventh grade of Creston Elementary School, Portland, Oregon. This class was described as an unusually disruptive group of students and was considered by the school as one of the most troublesome in the school\u27s history. The study focused on the concept of malperformance itself and the reliability of its assessment. The major hypotheses were these: A. Teachers are consistent among themselves in how they define malperformance and in whom they designate as malperformers. B. Teachers\u27 and students\u27 estimation of the students\u27 level of performance in the dimensions studied are positively related. C. A student\u27s self- estimate in the dimensions studied is related to his estimation of the teachers\u27 reactions to himself and other classmates. D. The label of malperformer is associated with lower ratings of personal behavior and school subject grades. E. Factors of sex, age, and I.Q. are related to malperformance. Each teacher was asked to define malperformance and to identify malperforming students in his class. Each student was asked if he felt the teachers liked him and if they were fair. The Pupil Behavior Inventory, a standardized rating scale dealing with five areas of student behavior, was administered to the teachers. A modified form of the Pupil Behavior Inventory was administered to each student to determine his assessment of his own behavior. Data was analyzed with the help of statistical tests of significance to evaluate the differences obtained. Study findings did not support the hypothesis that teachers are consistent among themselves in how they defined malperformance and which students they designated as malperformers. Each teacher defined malperformance differently. Some definitions were difficult to interpret in terms of specific behavior traits. There was only 53% marginal probability that another teacher would agree when a particular teacher designated a student as a malperformer. However, there was no significant difference in the number of students designated as malperformers by each teacher. Findings yielded evidence to support the hypothesis that there is a positive relationship between the teachers\u27 estimation of the level of the students\u27 performance and the students\u27 own assessment of his performance. Students designated as normals rated their own behavior very close to teacher ratings. In contrast, malperformers tended to rate their behavior much higher than did the teachers; however, malperformer self-ratings were lower than self-ratings of the other students. Malperformers had lower personal behavior and school subject grades than normals. No significant differences were found in the I. Q. range for normals and malperformers. This study indicated the need for more clarity and consistency in evaluating student behavior within the school system. Further research is needed in developing methods of identifying problem students and how to best help them

    Implicit Liquidity Premiums in the Disposition of RTC Assets

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    Recent research investigated the relationship between physical factors and the asking price of industrial buildings. We extend prior research by including physical, locational, financial, and economic variables to determine the factors that influence the sales price. This research provides an initial valuation framework for appraisers and is a first step toward the development of an industrial property index. Eleven variables - building size, office space, dock doors, ceiling height, age, distance to the Dallas/Fort Worth Airport, county of sale, industrial cap rate, prime rate, tenant type, and date of sale - are found to explain the sales price of industrial property.

    Ground penetrating radar applied to rebar corrosion inspection

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    In this paper we investigate the use of ground penetrating radar (GPR) to detect corrosion-induced thinning of rebar in concrete bridge structures. We consider a simple pulse/echo amplitude-based inspection, positing that the backscattered response from a thinned rebar will be smaller than the similar response from a fully-intact rebar. Using a commercial 1600-MHz GPR system we demonstrate that, for laboratory specimens, backscattered amplitude measurements can detect a thinning loss of 50% in rebar diameter over a short length. GPR inspections on a highway bridge then identify several rebar with unexpectedly low amplitudes, possibly signaling thinning. To field a practical amplitude-based system for detecting thinned rebar, one must be able to quantify and assess the many factors that can potentially contribute to GPR signal amplitude variations. These include variability arising from the rebar itself (e.g., thinning) and from other factors (concrete properties, antenna orientation and liftoff, etc.). We report on early efforts to model the GPR instrument and the inspection process so as to assess such variability and to optimize inspections. This includes efforts to map the antenna radiation pattern, to predict how backscattered responses will vary with rebar size and location, and to assess detectability improvements via synthetic aperture focusing techniques (SAFT)

    Escherichia coli bacteriuria in female adults is associated with the development of hypertension

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    AbstractObjectiveTo investigate whether Escherichia coli bacteriuria is associated with the development of hypertension during a long-term follow-up.MethodsA prospective cohort study was performed among the participants of two population-based studies. Between 1974 and 1986 all women aged 39 to 68 years old, who lived in Utrecht, the Netherlands, were invited to participate in a breast cancer screening program. The participants completed a questionnaire, underwent a medical examination, and collected a morning urine sample that remained stored. From 1993 to 1997 another population-based study was performed. We performed a full cohort analysis for 444 women who participated in both studies. E. coli bacteriuria was diagnosed by a real-time PCR. Hypertension was defined as the use of antihypertensive medication and/or a measured systolic blood pressure of at least 160 mmHg or a diastolic blood pressure of 95 mmHg or higher. The mean follow-up was 11.5±1.7 years.ResultsForty women (9%) had E. coli bacteriuria at baseline. Women who had bacteriuria at baseline had a mean blood pressure at study endpoint of 133±20 mmHg systolic and 78±11 mmHg diastolic, and women without bacteriuria had values of 129±20 and 78±11 mmHg, respectively (p-values for difference 0.33 and 0.88). Although E. coli bacteriuria was not associated with the blood pressure as a continuous variable, it was associated with the development of hypertension during follow-up (OR 2.8, 95% CI 1.4–5.5).ConclusionE. coli bacteriuria may increase the risk of future hypertension

    Cardiopulmonary bypass, myocardial management, and support techniques Changes in autonomic response of the cerebral circulation after normothermic extracorporeal circulation

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    AbstractPatients who undergo cardiopulmonary bypass frequently have neuropsychologic dysfunction. This study was undertaken to determine whether altered cerebral perfusion and vascular responses may in part lead to these neuropsychologic changes. Pigs were placed on normothermic cardiopulmonary bypass for 2 hours. Basal cerebral blood flow and in vivo responses to administration by internal carotid artery of neuronally released vasoactive substances were evaluated before and 5 to 15 minutes after termination of cardiopulmonary bypass. Another group of pigs were placed on cardiopulmonary bypass for 2 hours and then perfused off bypass for 1 additional hour. In vitro responses of cerebral arterial microvessels (100 to 175 μm) from both groups were examined in a pressurized (40 mm Hg) no-flow state with videomicroscopy. Vessels from uninstrumented pigs served as control preparations for in vitro studies. Cerebrovascular resistance and cerebral perfusion were maintained constant during cardiopulmonary bypass and after separation from bypass. The internal carotid artery infusion of acetylcholine (cholinergic agonist) caused increased internal carotid artery blood flow before cardiopulmonary bypass but decreased blood flow after cardiopulmonary bypass. After 2 hours of cardiopulmonary bypass, the increase in internal carotid artery blood flow induced by isoproterenol (a β-adrenoceptor agonist) was reduced, whereas the response to sodium nitroprusside (a guanylate cyclase activator) was unchanged. In vitro acetylcholine-induced microvascular vasodilation was converted to a contractile response and isoproterenol elicited less relaxation after 2 hours of cardiopulmonary bypass. One hour of cerebral perfusion after cardiopulmonary bypass caused a further reduction in isoproterenol-induced relaxation but had no further effect on the cholinergically mediated response. In vitro relaxation responses to sodium nitroprusside and forskolin (an adenylate cyclase activator) were similar in all experimental groups, suggesting that second-messenger mechanisms remain intact after normothermic cardiopulmonary bypass. In conclusion, basal cerebrovascular resistance and internal carotid artery blood flow are maintained if the systemic circulation and pressure are supported with fluid administration after cardiopulmonary bypass. Agonist-induced vasodilation of cerebral microvessels to cholinergic and β-adrenoceptor stimulation are selectively impaired after normothermic cardiopulmonary bypass, whereas second-messenger mechanisms remain intact. (J Thorac Cardiovasc Surg 1996;112:450-61

    721-6 Pulmonary Balloon Valvuloplasty: Effective Palliation for Infants with Tetralogy of Fallot and Small Pulmonary Arteries

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    Infants with tetralogy of Fallot (TOF) and small pulmonary arteries (PAs) may need palliation to improve pulmonary blood flow and allow growth of the PAs prior to complete repair. Shunts may become occluded, distort the PAs or cause pulmonary overcirculation. As an alternative palliation, we performed pulmonary balloon valvuloplasty (PBV) on infants with TOF and small PAs.20 infants, ages 1.8±1.5 mo and weights 4.1±1.6kg, undervvent PBV as initial palliation for persistent cyanosis or “spells”. 4/20 pts were intubated prior to or for PBV All pts had pre and post-PBV angiograms. In all pts, single balloon valvuloplasty was performed. The ratio of balloon: pulmonary valve annulus (PVA) diameter was 1.51±0.32. Post-PBV, there was no change in the PYA diameter (5.2±1.1mm vs 5.6 + 1.1mm; p=0.1) or PA branch diameter(4.1±1.6mm vs 4.5±1.7mm, p>0.05). The systemic 02 saturation increased from 81±8% to 93±6%. (p<0.001)7/20 pts undervvent follow-up (F/U) cath 8.2±2.4 mo post-PBV Compared to pre-PBV measurements, the PYA diameter increased from 5.2 ± 1.1mm to 7.1±1.4mm (p<0.03) and the McGoon ratio increased from 1.4±0.4 to 2.1±0.3 (p<0.02).Of the 20 pts, 11 pts undervvent corrective surgery 8.0±3.1 mo post-PBV with no surgical deaths; 5 pts remain in stable condition awaiting surgery; 3 pts required shunt placement 9-66 days post-PBV; 1 pt died due to other congenital anomalies.ConclusionsPulmonary balloon valvuloplasty promotes growth of the PAs and PYA in infants with TOF and small PAs, offering a safe and effective alternative palliation for infants who are not yet candidates for complete repair

    Effects of Coach and Parent Training on Performance Anxiety in Young Athletes: A Systemic Approach

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    Coaches and parents play a major role in determining the consequences of sport participation in young athletes. This study focuses on the assessment of a systemic, empirically inspired intervention directed at coaches and parents. Parallel workshops derived in part from achievement goal theory were presented to the coaches and parents of 9 to 15 year old boys and girls participating in community-based basketball programs, and their effects were compared with a matched control condition. Multilevel analyses revealed significant Time x Condition interactions on all three subscales of the Sport Anxiety Scale-2 (SAS-2) and on a total anxiety score. Athletes in the intervention condition decreased in cognitive and somatic anxiety scores on the SAS-2, whereas athletes in the control condition exhibited increases in cognitive and somatic anxiety. Results suggest the potential efficacy of brief, economical interventions in enhancing the psychosocial impact of the youth sport environment

    Lunar surface mechanical properties — Surveyor 1

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    Engineering telemetry data and lunar surface photographs by Surveyor 1 have been evaluated for information on the mechanical properties of the lunar surface material at the Surveyor 1 landing site. Based primarily on photographic evidence, estimates of soil density, cohesion, and other soil characteristics are presented. Also, the mechanisms in which the lunar material is believed to have failed under the footpad impacts are discussed. Because dynamic soil reactions cannot be interpreted directly from the available data, a comparative study using computer-simulated landings was initiated. Preliminary results of this study, which is still in progress, are presented

    Are your covariates under control? How normalization can re-introduce covariate effects

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    Many statistical tests rely on the assumption that the residuals of a model are normally distributed. Rank-based inverse normal transformation (INT) of the dependent variable is one of the most popular approaches to satisfy the normality assumption. Studies regularly adjust for covariates and then normalize the residuals. This study investigated the effect of regressing covariates against the dependent variable and then applying rank-based INT to the residuals. The correlation between the dependent variable and covariates at each stage of processing was assessed. An alternative approach was tested of applying rank-based INT to the dependent variable before regressing covariates was tested. Analyses based on both simulated and real data examples demonstrated that applying rank-based INT to the dependent variable residuals after regressing out covariates re-introduces a linear correlation between the dependent variable and covariates in almost all situations. This will increase type-1 errors and reduce power. Our proposed alternative approach, where rank-based INT was applied prior to controlling for covariate effects, gave residuals that were normally distributed and linearly uncorrelated with covariates. This approach is therefore recommended
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