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PubMed1997

The continuous performance test, identical pairs version (CPT-IP): III. Brain functioning during performance of numbers and shapes subtasks.

The numbers and shapes subtasks of the CPT-IP are difficulty-matched measures of independent aspects of attentional skill that have been used to differentiate the impairments of schizophrenics and major depressives. Previous studies suggest that they tap into lateralized aspects of attentional performance. To investigate this hypothesis, seven subjects free of psychiatric illness were presented with these CPT-IP subtasks during a SPECT procedure. Subtasks--4-digit number strings and nonsense shapes--were administered on successive weeks, in counterbalanced order, simultaneous with administration of 10 mCi 99mTc HMPAO. Scanning took place after 10 min of test performance. Quantitative data were extracted from each scan via a semi-automated region of interest (ROI) analysis which defined eight cortical and four subcortical ROI on each of five transverse slices. Data for each ROI were normalized and compared between task conditions. Results indicate that the two tasks produce different patterns of functioning within two general areas of the brain. First, during Numbers task performance, left-sided activity was increased on multiple transverse slices in an anterior subcortical region that incorporated the anterior cingulate, frontal white matter, and much of the basal ganglia. Left-sided activity was also increased in a posterior subcortical region including the left side of the thalamus. Lateralization of function, defined as relative activity on the left and right sides, changed within these regions across tasks, but primarily as a result of the contribution of increased or decreased activity on the left side alone. Second, relative perfusion to occipital regions, bilaterally, was more extensive during the Shapes task. These results suggest that subtle alterations in stimulus parameters can affect activation patterns in regions that are critically associated with task performance. They also suggest that the Numbers task may provide more robust activation of anterior attention systems, that may better discriminate the functioning of these systems in normal and psychopathological groups.

Adult↗

PubMed2001

The Montreal rehabilitation performance profile: a task-analysis approach to quantify stair descent performance in children with intellectual disability.

OBJECTIVE: To develop a clinical tool to quantify stair descent performance in children with moderate to severe intellectual disability. DESIGN: Item identification, measurement construction, and basic testing of reliability. SETTING: School for children with intellectual disability. PARTICIPANTS: A sample of convenience; 18 children (age range, 5-9 yr) with moderate to severe intellectual disability, but who were ambulatory. INTERVENTION: The Montreal Rehabilitation Performance Profile (MRPP) measurement tool, which has 4 perceptual-motor elements: movement form, time requirement, proprioceptive cues, and external cues. MAIN OUTCOME MEASURE: Identification of perceptual-motor elements that underlie skilled stair descent and that are directly quantified from standard video recording. RESULTS: Interrater reliability measured by percentage agreement (kappa statistic) was high for 3 elements (80%-100%; kappa =.63) and good for the fourth (67%; kappa =.52). The 4 MRPP elements are plotted on cartesian axes to yield (1) the magnitude of the contribution of each independent element to total performance outcome, and (2) a global measurement of level of functional skill, the Performance Composite Score (PCS). CONCLUSIONS: The MRPP, and associated PCS, provide a valid measure of functional stair descent skill that does not rely on cognitive understanding of the process. This tool could be adapted to measure functional capacity in other clinical populations, including geriatric clients.

Child↗

PubMed1976

Dietary fat level as affecting running performance and other performance-related parameters of rats restricted or non-restricted in food intake.

The effect of food energy density on certain physical performance characteristics of rats was studied during ad libitum and weight-restricted feeding. After a 16-week treadmill training period, 48 young adult male Long-Evans rats were divided into six groups, receiving 20%, 40% or 70% of energy as dietary fat and fed ad libitum or 40% by weight of average ad libitum intake. They were run to exhaustion once a week. Increased dietary fat level was not correlated with superior running performance at either food intake level, although during restricted feeding the high fat group received 40% more energy than the low fat group. Lower body weight was correlated with increased running performance at both food intake levels. The rate of performance increase with decreasing body weight during food restriction was significantly higher for the low fat than for the high fat group. Water consumption was considerably lower during restricted than during ad libitum feeding. Plasma glucose was lower when the 70% fat diet was fed than when compared to the other fat diets at both levels of food intake, lower from day 8 on of restricted that during ad libitum food intake, and lower on day 15 than on day 8 of the restricted intake.

Animals↗

PubMed1998

Performance of the Continuous Performance Test among community samples.

The Continuous Performance Test (CPT) has been modified to be used widely as a potential vulnerability marker of schizophrenia. In genetic analyses of schizophrenia, well-established norms for the CPT are essential in choosing a suitable threshold of CPT for classifying subjects as affected or unaffected. In this study, we investigated the performance of 115 adolescents and 345 adults, randomly sampled from a community, on two sessions of the CPT 1-9 (undegraded and 25% degraded). The results showed that an older age was associated with a decreasing hit rate and sensitivity (d'), while a higher level of education was associated with an increasing hit rate and d' for both sessions of the CPT. Men had higher hit rates and d' than women for the degraded CPT. A practice effect during the second session of the CPT was noted among 20 to 33 percent of the subjects. Poorer CPT performance was associated with schizotypy measured by the Perceptual Aberration Scale and the Schizotypal Personality Questionnaire. Thus, in assessing CPT performance among schizophrenia patients or high-risk populations, we must compare their results to age-, education-, and sex-corresponding norms. The data presented in this report will be valuable in this regard.

Adolescent↗

PubMed1980

Performance on PMPs and performance in practice: are they related?

A study was conducted to test the criterion validity of a set of patient management problems (PMPs) through a direct behavior-by-behavior comparison of performance on the PMPs and performance in the practice setting. The PMP cases were replicated in the practice setting through the use of role-playing actors. At the time of the encounter the subjects in the study believed these actors to be real patients. Between PMP performance and practice performance there were major inconsistencies, characterized by substantially greater errors of omission and commission in the practice setting.

British Columbia↗

PubMed1993

Comparing medical school graduates who perform poorly in residency with graduates who perform well.

BACKGROUND: Most medical school graduates perform well as residents. However, the authors' annual surveys have shown that a few graduates from each class at their school fail to meet residency directors' expectations. METHOD: The medical school records of the 20 of the 153 graduates from the class of 1983 at the University of California, San Francisco, School of Medicine who received poor evaluations from their residency directors in the first and/or second year of residency were compared with the records of 20 of their best-received classmates. The poorly received graduates did not necessarily receive poor numerical ratings of their knowledge, skills, or overall performances, but they did receive negative or ambivalent responses to the following question: "Knowing what you now know about this resident, would select him or her again? Please explain." The two groups of graduates were matched for sex, racial-ethnic identification, and residency discipline. RESULTS: The groups were quite similar with respect to qualifications for admission to medical school, overall academic achievement, and performance on standardized national examinations. There were minor differences in performances on clinical clerkships. CONCLUSION: As indicated by residency directors' ratings and comments, most of the poorly received graduates' problems during residency appear to have been personal and motivational rather than skills- or knowledge-related. With but few exceptions, the medical school records contained little evidence that might have predicted the graduates' poor reception as residents.

Adult↗

PubMed2003

Chronic medical conditions and work performance in the health and work performance questionnaire calibration surveys.

Associations between chronic conditions and work performance (absenteeism, presenteeism, and critical incidents) were studied in reservation agents, customer service representatives, executives, and railroad engineers. Conditions and work performance were assessed with the World Health Organization's Health and Work Performance Questionnaire. Analysis of covariance was used to estimate associations. More work performance was lost from presenteeism than absenteeism. However, chronic conditions more consistently had negative impacts on absenteeism than presenteeism. Conditions with significant effects included arthritis, asthma, chronic obstructive pulmonary disease-emphysema, depression, and chronic headaches. Arthritis had the largest aggregate effect on absenteeism-presenteeism. Only depression affected both absenteeism-presenteeism and critical incidents. Some chronic conditions have substantial workplace effects. Disease management programs for these conditions might have a positive return on investment (ROI). Health and productivity tracking surveys are needed to evaluate ROI and provide quality assurance.

Absenteeism↗

PubMed2004

Coronary bypass surgery performed off pump does not result in lower in-hospital morbidity than coronary artery bypass grafting performed on pump.

BACKGROUND: There is increasing evidence that cardiopulmonary bypass (CPB) may be responsible for the morbidity associated with coronary artery bypass grafting (CABG) surgery. Recent developments in cardiac stabilization devices have made CABG without CPB feasible. However, there is conflicting evidence to date from published trials comparing outcomes between CABG performed with and without CPB, with some trials indicating an advantage to the avoidance of CPB and others showing little benefit. METHODS AND RESULTS: In a single-center randomized trial, 300 patients requiring CABG surgery at a single institution were prospectively randomized to have the procedure performed with CPB (n=150) or on the beating heart (n=150). Exclusion criteria for the trial included emergency procedure, concomitant major cardiac procedures, ejection fraction <30%, and reoperation. In-hospital outcomes were analyzed on an intention-to-treat basis. A mean of 3.0+/-0.9 grafts were performed in the CPB group compared with 2.8+/-0.9 grafts in the beating-heart group (P=0.06). There were no significant differences between the CPB group and the beating-heart group in mortality (0.7% versus 1.3%; P=1.0), transfusion (8.7% versus 9.3%), perioperative myocardial infarction (0.7% versus 2.7%; P=0.37), permanent stroke (0% versus 1.3%; P=0.50), new atrial fibrillation (32% versus 25%; P=0.20), and deep sternal wound infection (0.7% versus 0%; P=1.0). The mean time to extubation was 4 hours, the mean stay in the intensive care unit was 22 hours, and the median length of hospitalization was 5 days in both groups (P=NS). CONCLUSIONS: In contrast to published trials, we were unable to demonstrate any advantage with CABG performed without CPB in terms of patient morbidity. Excellent results can be obtained with either surgical approach.

Adult↗

PubMed2005

Effect of COMT Val158Met polymorphism on the Continuous Performance Test, Identical Pairs Version: tuning rather than improving performance.

OBJECTIVE: It has been suggested that variation in catechol O-methyltransferase (COMT) activity associated with variation in COMT Val158Met genotypes may result in enhanced or reduced cognitive performance, depending on whether the phenotype requires cognitive stability or cognitive flexibility. The authors' goal was to determine whether, in confirmation of this prediction, performance on a measure of cognitive stability would be associated with Met loading. METHOD: COMT genotyping was investigated in relation to a measure of reaction time variability on the Continuous Performance Test, Identical Pairs Version, in a large and representative sample of 527 young men (mean age=21 years). RESULTS: Met loading was associated with reduced reaction time variability. CONCLUSIONS: Met genotype loading may confer enhanced "tuning" or greater stability in performance, possibly by stabilizing active neural representations in the prefrontal cortex during tasks involving working memory.

Adult↗

PubMed2006

Effects on WAIS-III performance IQ (PIQ) and full scale IQ (FSIQ) when object assembly is substituted for each standard performance scale subtest.

According to the WAIS-III Administration and Scoring Manual, Object Assembly (OA) may be substituted for any spoiled Performance subtest. This assertion has not been evaluated in a clinical sample. The present investigation reports differences that resulted in Performance IQ (PIQ) and Full Scale IQ (FSIQ) when OA replaced each of the Performance subtests. Participants were 47 referrals for neuropsychological assessment (age M = 45.98 years, SD = 9.82; education M = 13.82 years, SD = 2.78). Results indicated that OA may replace any Performance subtest without seriously altering the summary scores. Differences between the standard IQs and OA-based composites were < 2 points for PIQ and < 1 point for FSIQ. More than 90% of the OA-based composites fell within the 90% confidence limits of the corresponding IQ.

Adult↗

PubMed1995

The thermal acclimation of burst escape performance in fish: an integrated study of molecular and cellular physiology and organismal performance

Goldfish (Family Cyprinidae, Carassius auratus) and killifish (Family Cyprinodontidae, Fundulus heteroclitus) were acclimated to 10, 20 and 35 °C for 4 weeks. The thermal acclimation of C-start (escape swimming) performance and the physiological properties of fast twitch muscle fibres that underlie it were investigated in these species at the molecular (myosin isoform expression), biochemical (myofibrillar ATPase activity), cellular (contractile kinetics) and organismal levels of organisation. Peptide maps were obtained for fast muscle myosin heavy chains, isolated from 10 °C- and 35 °C-acclimated fish. Different myosin heavy chain isoforms were expressed in response to a change in acclimation temperature in goldfish, but myosin heavy chain isoform expression was unaffected by acclimation temperature in killifish. Compared with fish acclimated to 35 °C, acclimation to 10 °C increased the activity of fast muscle myofibrillar ATPase assayed at 10 °C fivefold in goldfish and only 50 % in killifish. Muscle twitch contraction time at 10 °C decreased significantly in response to acclimation to 10 °C in both species; however, the magnitude of this response was much greater in goldfish (100 %) than in killifish (30 % or less). In goldfish, these changes in the physiological properties of fast twitch fibres during 10 °C acclimation resulted in a six- to eightfold increase in the speed and turning velocity of fish performing C-starts at 10 °C. By comparison, the somewhat smaller acclimatory response of killifish fast muscle properties was accompanied by only a minor (50 % or less) adjustment in locomotor performance. Thermal acclimatory responses of fast muscle at the molecular, biochemical and cellular levels of organisation are clearly reflected in alterations in organismal escape performance.

Journal Article↗

PubMed2006

RAPID for high-performance computing systems: architecture and performance evaluation.

The limited bandwidth and the increase in power dissipation at longer communication distances and higher bit rates will create a major communication bottleneck in high-performance computing systems (HPCS), affecting not only their performance, but also their scalability. As a solution, we propose an optical-interconnect-based architecture for HPCS called reconfigurable all-photonic interconnect for parallel and distributed systems (RAPID) that alleviates the bandwidth density, optimizes power consumption, and enhances scalability. We also present two cost-effective design alternatives of the architecture, a modified version called M-RAPID and an extended version called E-RAPID that minimizes the cost of the interconnect based on the number of transmitters required. We perform a detailed simulation of the proposed RAPID architecture and compare it to several electrical HPCS interconnects. Based on the performance study, RAPID architecture shows 30%-50% increased throughput and 50%-75% reduced network latency as compared to HPCS electrical networks.

Journal Article↗

PubMed1985

Comparison of drug effects on fixed-ratio performance and chain performance maintained under a second-order fixed-ratio schedule.

In one component of a multiple schedule, pigeons were required to complete the same four-response chain each session by responding sequentially on three identically lighted keys in the presence of four successively presented colors (chain performance). Food presentation occurred after five completions of the chain (i.e., after 20 correct responses). Errors, such as responding on the center or right key when the left was designated correct, produced a brief timeout but did not reset the chain. In the other component, responding on a single key (lighted white) was maintained by food presentation under a fixed-ratio 20 schedule. In general, phencyclidine and d-amphetamine produced dose-dependent decreases in the overall response rates in both components. With pentobarbital, overall rate in each component generally increased at intermediate doses and decreased at higher doses. All three drugs produced dose-dependent disruptive effects on chain-performance accuracy. Phencyclidine and pentobarbital increased percent errors at doses that had little or no rate-decreasing effects, whereas d-amphetamine generally increased percent errors only at doses that substantially decreased overall rate. At high doses, all three drugs produced greater disruption of chain performance than of fixed-ratio performance, as indicated by a slower return to control responding, although the effects of d-amphetamine were less selective than those of phencyclidine or pentobarbital.

Animals↗

PubMedDate not supplied

Exercise, performance and temperature control: temperature regulation during exercise and implications for sports performance and training.

Thermoregulation is an important consideration not only for athletic performance but also for the safety of the athlete. This article presents a broad overview of the mechanisms by which body heat is dissipated in an individual exercising in a hot environment. Particularly emphasised are more recent views of body heat loss mechanisms and the influences of non-thermal inputs, such as effects due to changing blood volume or blood flow distribution. During exercise in a hot environment, metabolic heat produced by the exercising muscles is transported by the circulating blood to the surface of the body where it is released to the environment, either by radiation and convection or by evaporation of sweat. The primary drives for both the increased skin blood flow and increased body sweating are the thermal inputs which are sensed by receptors in the deep body core, with a lesser drive from skin receptors. These thermal signals are integrated in the hypothalamus and proper heat loss responses are effected. When exercise is prolonged, however, and body rehydration is not adequate, the total blood volume may be compromised. In addition, as the core temperature increases during exercise, larger proportions of the blood volume are distributed to the cutaneous vessels, thus effectively reducing cardiac return and central blood volume. During severe exercise, a reduction in cardiac filling may result in a fall in central venous pressure and stimulate baroreceptor vasoconstrictor reflexes. As discussed below, the outputs from these baroreceptors compete with and modify the thermal drives for both the control of the skin blood flow and control of the sweat glands. The effect of high ambient temperatures on exercise performance is most evident in prolonged submaximal exercise. Normally, maximal exercise performance is not altered by high temperatures unless the individual has an elevated deep body temperature before the start of the exercise task. However, submaximal exercise performance is often impaired by high ambient temperatures, but may be improved by programmes of physical training and heat acclimatisation. Both training and heat acclimatisation significantly modify the control systems which regulate skin blood flow and sweating. Only acclimatisation programmes, however, are effective in preventing heat stress during prolonged exercise in hot environments.

Animals↗

PubMed1998

Combined effects of goal setting and performance feedback on performance and physiological response on a maximum effort task.

A laboratory experiment was conducted (N = 40 subjects) to examine whether goal setting would be associated with reduced heart rate on an endurance task. Participants performed an endurance task on an ergometer bicycle. One week later when participants performed the task again half of them set a specific personal goal for an increase in performance. Analysis indicated that subjects who set a goal showed significant improvement in comparison with the control group. Moreover, subjects in the goal group had a significantly lower mean heart rate during the test and had a higher mean heart rate at the end of the test than on the first trial. Results are discussed in terms of combining cognitive and physiological explanations for the beneficial effects of goal setting on performance.

Adult↗

PubMed2005

Effects of supplementation of whole corn germ on reproductive performance, calf performance, and leptin concentration in primiparous and mature beef cows.

A 2-yr study using primiparous and multiparous, spring-calving, crossbred beef cows was conducted to evaluate the effects of supplemental whole corn germ on reproductive performance, calf performance, and serum leptin concentrations. Each year, cows were blocked by age and BCS and assigned randomly to one of three treatments: PRE (n = 115) cows received 1.14 kg/d (DM basis) of whole corn germ for approximately 45 d before calving; POST (n = 109) cows were fed 1.14 kg/d of whole corn germ for approximately 45 d after calving; and control cows (n = 118) were fed similar energy and protein from dry-rolled corn (1.82 kg of DM/d) for 45 d before and after calving. Additionally, PRE cows were grouped with controls after calving, and POST cows were grouped with control cows before calving, so that corn germ-supplemented cows received the control supplement in the alternate feeding period. Cow BW (538 +/- 13 kg) and BCS (5.4 +/- 0.13) did not differ among treatments at any time during the experiment. Calf birth weight (39 +/- 2 kg), weaning weight (225 +/- 7 kg), and age-adjusted weaning weight (234 +/- 8 kg) did not differ because of dam supplementation regimen. Treatment did not affect the proportion of cows exhibiting ovarian luteal activity before the start of the breeding season (67%) or pregnancy rate (91%). The interval from exposure to bulls until subsequent calving did not differ (P = 0.16) among PRE (298 +/- 2.3 d), POST (303 +/- 2.6 d), and control (304 +/- 2.3 d) cows. Leptin concentrations did not differ among treatments and were 2.15 +/- 0.75, 1.88 +/- 0.76, and 1.91 +/- 0.75 ng/mL for control, POST, and PRE cows, respectively. Age and week relative to calving influenced leptin concentration. Primiparous cows had similar leptin concentrations to 3-yr-old and mature cows for wk -7 and -6 relative to calving, but lower (P < 0.10) concentrations than mature cows for wk -5, and lower (P < 0.05) concentrations than either 3-yr-old or mature cows for wk -4 to +7 relative to calving. Serum leptin was correlated with BCS (P < 0.0001; r = 0.35) at initiation of the feeding period and was correlated with BCS (P = 0.02; r = 0.12) and weight (P < 0.01; r = 0.14) at the completion of the supplement period, but it was not correlated with initial BW or interim BCS. Calving interval was not correlated (P > 0.12) with weekly measures of serum leptin concentration. Supplementing beef cows with whole corn germ had no effect on cow performance, calf performance, or serum leptin concentrations of cows.

Aging↗

PubMed2006

Influence of genotype and diet on steer performance, manure odor, and carriage of pathogenic and other fecal bacteria. I. Animal performance.

Although Brahman crosses constitute a large portion of US beef cattle, little information is available on their response to diverse feed resources compared with Bos taurus steers. Thus, the objectives were to evaluate genotype and diet effects on steer performance during the growing period and subsequent response to a high grain diet during the finishing period. Fifty-one steers [0 (15), 1/4 (20), 1/2 (7), and 3/4 Brahman (9), with the remaining proportion being MARC III] were allotted to 8 pens. Beginning on December 2, steers were individually fed chopped bromegrass hay (n = 26; DM = 85%, CP = 9.5%, ME = 2.19 Mcal/kg) or a corn silage-based diet (n = 25; DM = 51%, CP = 11.9%, ME = 2.75 Mcal/kg) for 119 d. All steers were then fed a high corn diet (DM = 79%, CP = 11.7%, ME = 3.08 Mcal/kg) to a target BW of 560 kg (176 d). Data were analyzed by ANOVA, with genotype, growing diet, and the 2-way interaction included. The interaction was not significant (P > 0.25). The MARC III and 1/2 Brahman steers weighed more (P < 0.01) than 1/4 or 3/4 Brahman steers initially and at the end of the growing period. Weight of bromegrass-fed (325 kg) steers was less than that of corn silage-fed (384 kg) steers at the end of the growing period. Steer ADG and intake of DM, CP, and ME were less (P = 0.087 to 0.001) for 1/4 and 3/4 Brahman than for 0 or 1/2 Brahman steers during growing, finishing, and total, but efficiency of gain did not differ (P > 0.10). Carcass weight, marbling score, quality grade (P < 0.05), and kidney fat (P = 0.06) differed among genotypes. Daily DMI (6.91 vs. 7.06 kg) was similar, but CP (0.66 vs. 0.84 kg) and ME (15.2 vs. 19.4 Mcal) intake of bromegrass fed was less (P = 0.001) than those of corn silage-fed steers. Values for DMI/gain (22.3 vs. 7.43 kg/kg), CP intake/gain (2.13 vs. 0.88 kg/kg), and ME intake/gain (48.8 vs. 20.4 Mcal/kg) were greater (P < 0.001) in bromegrass-fed than corn silage-fed steers. Over the total study, ADG was lower (0.96 vs. 1.01 kg), and DMI (7.82 vs. 7.19 kg), DMI/gain (8.21 vs. 7.10 kg/kg), and ME intake/gain (22.6 vs. 20.9 Mcal/kg) were greater (P < 0.05) in bromegrass-fed than in corn silage-fed steers. Carcass weight, dressing percent, adjusted backfat, and yield grade (P < 0.05) were greater for corn silage-fed than for bromegrass-fed steers. Feed intake and performance, but not efficiency, differed among these genotypes. Compensatory performance during finishing was insufficient to overcome reduced performance during the growing period.

Animal Feed↗

PubMed2005

[Development of clinical performance indicators for establishing a connecting system between hospital performance management and quality improvement].

PURPOSE: This study aimed at developing integrated clinical performance indicators(CPIs) through the analysis of quality improvement(QI) activities of a hospital and literature review about performance measures. METHOD: The CPIs were developed through the following three stages; 1)Identifying preliminary CPIs 2)A staff validity test in preliminary CPIs 3)Developing final CPIs. RESULT: One hundred twenty-three preliminary CPIs were developed through QI activities of the target hospital for 8 years and literature review. The results of the validity test for the preliminary CPIs supported ninety-one items. Sixty-two CPIs were selected through integration, reclassification and renaming. Then, eighteen items were deleted on account of an imprecise calculation method. Finally, forty-four CPIs were confirmed. They consisted of twenty-six items at the hospital level and eighteen items at the department level. CONCLUSION: CPIs can be used as criteria to evaluate the performance of healthcare organizations, and to decide the quality of healthcare for customers. This study may contribute to establishing an integrated system between QI activities and performance measurement of healthcare organizations.

Adult↗