Relative Performance Levels Research Articles

Assessing the factors underlying differences in achievements of farmer groups: methodological issues and empirical findings from the highlands of Central Kenya

This paper examines the performance of rural-based community groups in Central Kenya and addresses the methodological issues and challenges faced in doing this. Performance measures included subjective and objective ratings of success, including more objectively verifiable measures at household and group levels, derived from a survey of 87 groups and 442 households within four sites. Empirical evidence regarding explanatory factors for relative performance levels is presented using a special sample of 40 groups involved in tree nursery activities, with both descriptive analysis and regression models. Collective action is desired and practised for many tasks. The incredible number, diversity and dynamic nature of groups make it difficult to standardise and measure achievement. Choice and level of performance measures matters in explaining differences in group achievement. Focusing on groups undertaking similar activities allows deeper analysis of performance drivers. Examining different types of groups engaged tree nurseries found that performance was not linked to any easy-to-measure group characteristic, implying that for this task dissemination need not be targeted towards particular types of groups.

Policy issues for Australia's education systems: Evidence from international and Australian research

Our purpose here is to discuss education policy issues in the context of empirical evidence. We note that many commonly held beliefs about Australian education such as, the relative performance and participation levels of Australian students; the importance of socioeconomic background on educational outcomes both relative to other countries and changes over-time; gender differences in mathematics and science; and the labour market situation of early school leavers; are not supported by empirical research. Such findings have implications for government policies. We also question current policy directions toward increasing Year 12 participation, expanding both secondary and post-secondary vocational education and reducing class sizes. It is hoped that the discussion will provide stimulus to evidence-based debates about Australian education.

علاقة القوة النسبية والوزن في مستوى الأداء المهاري في رياضة الجمناستك لدى طلبة تخصص التربية الرياضية

The purpose of this study was to investigate the relationship of relative strength weight and skill performance in Gymnastics of physical Education Major. The sample of the study consisted of (25) students, (15) male, and (10) Female, whom they were finished Gymnastics (1) and (2). The results revealed a significant positive correlation among relative strength, weight and performance, where (R2) (0.726) the contribution of relative strength in predicting performance was (44.5%), and (28.5%) for weigh. Based on the study findings the researcher recommended to use light weigh exercise, and follow up the students’ body weight. هدفت الدراسة إلى معرفة علاقة القوة العضلية النسبية والوزن في تطوير مستوى الأداء المهاري في رياضة الجمناستك، لتحقيق ذلك أجريت الدراسة على عينة عمدية من طلبة تخصص التربية الرياضية والبالغ عددهم (15) طالبا و(10) طالبات ممن أنهوا مساق الجمناستك (1) وجمناستك (2). أظهرت النتائج وجود علاقة إيجابية بين القوة النسبية والوزن مع الأداء المهاري في رياضة الجمناستك لدى طلبة تخصص التربية الرياضية، حيث وصل معامل الارتباط بيرسون بينهما إلى (0.726). وفيما يتعلق بمساهمة القوة النسبية في الأداء المهاري، أظهرت نتائج معامل الانحدار (R2) أنها تفسر ما نسبته (44.5 %) من الأداء المهاري، وفيما يتعلق بالوزن فانه يفسر ما نسبته (28.5 %)، وكلاهما يفسر ما نسبته (73%) من الأداء المهاري. أوصى الباحثان بضرورة استخدام التمارين بالأثقال وبأوزان خفيفة بالإضافة إلى متابعة أوزان الطلبة والاهتمام بتنمية القوة الخاصة بالجمناستك.

Accuracy and Fluency in List and Context Reading of Skilled and RD Groups: Absolute and Relative Performance Levels

The purpose of this study was to examine (1) the performance levels and the magnitude of performance difference between students with reading disabilities (RD) and skilled readers when reading a typical classroom text; (2) the hypothesis that students with RD have specific difficulty using context in such a way that reading fluency is affected; and (3) whether RD subtypes may be differentiated according to performance on contextual and context‐free reading tasks. Two groups of fourth graders (85 skilled readers and 24 students with RD) completed a standardized test of reading comprehension, read aloud a folktale, and read aloud the folktale's words in a randomly sequenced list. Performance was scored as correct rate and percentage correct. Based on the number of words per idea unit in the passage, we also estimated the rate at which reader groups encountered and processed text ideas. Compared to the RD group, skilled readers read three times more correct words per minute in context, and showed higher accuracy and rates on all measures. Both context and isolated word‐reading rates were highly sensitive to impairment. We found no evidence for RD subtypes based on these measures. Results illustrate differences in reading levels between the two groups, the temporal advantage skilled readers have in linking text ideas, how word reading differs as a function of task format and performance dimension, and how limited word‐identification skills (not comprehension) produce contextual reading difficulties for students with RD.

Postharvest Biological Control of Potato Sprouting by Fusarium Dry Rot Suppressive Bacteria

Chemical sprout inhibitors are applied to over 50% of the potato harvest to extend storage time. In the U.S.A., CIPC (1-methylethyl-3-chlorophenylcarbamate) is the only synthetic chemical registered for postharvest sprout control of stored potatoes, and it is the most widely used sprout inhibitor world-wide. Due to environmental and health safety concerns, the use of CIPC has become more restricted, and alternative sprout control methods are sought. Six bacteria strains, exhibiting superior dry rot suppressiveness in previous research, were grown in two different liquid culture media and sprayed on Russet Burbank potatoes. In growth chamber and pilot experiments repeated at two storage sites in two successive years, all six isolates demonstrated significant sprout control capabilities when applied after growth on at least one of the culture media supplied. Of the six strains tested, Pseudomonas fluorescens bv.V S11:P:12 and two strains of Enterobacter sp., S11:T:07 and S11:P:08, exhibited highest relative performance levels with sprout control being statistically similar to that of 16.6 ppm CIPC thermal fog after 4-5 months storage.

Combined pool/bilateral dispatch. II. Curtailment of firm and nonfirm contracts

This paper deals with the dispatch of power networks under mixed pool/bilateral trading. The major questions that are examined are the following: (1) To what degree does the relative level of pool versus bilateral trading influence performance in terms of individual power levels, costs, prices, and revenues? (2) What is the comparative performance of mixed trading with firm and nonfirm bilateral contracts under various curtailment strategies? (3) Is the revenue derived from the pool and bilateral trading consistent with the corresponding unbundled costs? The above questions are sequentially addressed in separate parts of this three-part paper. The eventual goal of these results is to help generator and load-serving entities choose appropriate relative levels of pool versus bilateral trades while considering risk, economic performance, and physical constraints. In Part II, two types of bilateral contracts, firm and nonfirm, are introduced together with their respective curtailment and noncurtailment bids. The optimal power-flow problem from Part I is now modified to accommodate this new type of operation. Technical and economical performance measures defined in Part I, namely, generation revenues from bilateral and pool sales, pool demand payments, plus generation and load expenditures to cover transmission loss and congestion management attributed to bilateral exchanges are also used here together with revenues from contract curtailment and expenditures due to noncurtailment bidding. Simulation results illustrate the effects of firm and nonfirm contracts and their bidding strategies on the relative levels of pool/bilateral trading, as well as on economic performance of market participants.

Combined Pool/Bilateral Dispatch, Part II: Curtailment of Firm and Nonfirm Contracts

This paper deals with the dispatch of power networks under mixed pool/bilateral trading. Three major questions are examined in separate parts of this three-part paper. To what degree does the relative level of pool versus bilateral trading influence performance in terms of individual power levels, costs, prices, and revenues? What is the comparative performanceof mixed trading with firm and nonfirm bilateral contracts under various curtailment strategies? Is the revenue derived from the pool and bilateral trading consistent with the corresponding unbundled costs? The eventual goal is to help generator and load-serving entities choose appropriate relative levels of pool versus bilateral trades while considering risk, economic performance, and physical constraints. In Part II, two types of bilateral contracts, firm and nonfirm, are introduced together with their respective curtailment and noncurtailment bids. The optimal power flow problem from Part I is now modified to accommodate this new type of operation. Technical and economical performance measures defined in Part I (namely, generation revenues from bilateral and pool sales, pool demand payments, plus generation and load expenditures to cover transmission loss and congestion management attributed to bilateral exchanges) are also used here together with revenues from contract curtailment and expenditures due to noncurtailment bidding. Simulation results illustrate the effects of firm and nonfirm contracts and their bidding strategies on the relative levels of pool/bilateral trading, as well as on economic performance of market participants.

Which Reward Structure Works Best? A New Perspective on Cooperation and Competition in Teams

A contingency model of reward structures is developed, stating that the relationship between reward structure and team performance is contingent upon the performance dimension specified (speed vs. accuracy), team composition (team members' interpersonal orientation in terms of extroversion and agreeableness), and the relative performance level of individual team members. In a laboratory experiment, 75 four-person teams engaged in an interactive command and control task, in which reward structure (cooperative vs. competitive) was manipulated. Results showed that a competitive structure enhanced speed, whereas a cooperative structure enhanced accuracy. Moreover, teams high on extroversion and agreeableness performed better under a cooperative structure, whereas teams low on these orientations performed better under a competitive structure. Finally, reward structure had a stronger impact on poorer than on stronger performing team members.

Combined pool/bilateral dispatch. I. Performance of trading strategies

This three-paper series deals with the dispatch of power networks under mixed pool/bilateral trading. The major questions examined are (i) to what degree does the relative level of pool versus bilateral trading influence performance in terms of individual power levels, costs, prices, revenues and expenditures; (ii) what is the comparative performance of mixed trading with firm and nonfirm bilateral contracts under various curtailment strategies; and (iii) is the revenue derived from the pool and bilateral trading consistent with the corresponding unbundled costs? The above issues are sequentially addressed in each of the three parts. The eventual goal of these results is to help generator and load-serving entities choose appropriate relative levels of pool versus bilateral trades while considering risk, economic performance, as well as physical constraints. This paper proposes a one-step optimal power flow model that dispatches the pool in combination with the privately negotiated bilateral contracts while minimizing cost and accounting for both losses and congestion. In part I, notions of pool/bilateral demand and generation as well as a number of technical and economic performance measures for each competing entity are defined. This dissection of total and individual financial measures according to pool or bilateral trading allows the market participant to evaluate the profitability of each component of its chosen pool/bilateral mix. A number of simulation results illustrate the effect of varying the relative levels of pool/bilateral trading on the values of individual performance measures.

Combined Pool/Bilateral Dispatch-Part 1: Performance of Mixed Trading Strategies

This three-paper series deals with the dispatch of power networks under mixed pool/bilateral trading. The major questions examined are: (i) To what degree does the relative level of pool versus bilateral trading influence performance in terms of individual power levels, costs, prices, revenues, and expenditures? (ii) What is the comparative performance of mixed trading with firm and nonfirm bilateral contracts under various curtailment strategies? (iii) Is the revenue derived from the pool and bilateral trading consistent with the corresponding unbundled costs? These issues are sequentially addressed in each of the three parts. The eventual goal of these results is to help generator and load-serving entities choose appropriate relative levels of pool versus bilateral trades while considering risk, economic performance, and physical constraints. This paper proposes a one-step optimal power flow model that dispatches the pool in combination with the privately negotiated bilateral contracts while minimizing cost and accounting for both losses and congestion. In Part I notions of pool/bilateral demand and generation, as well as a number of technical and economic performance measures for each competing entity, are defined. This dissection of total and individual financial measures according to pool or bilateral trading allows the market participant to evaluate the profitability of each component of its chosen pool/bilateral mix. A number of simulation results illustrate the effect of varying relative levels of pool/bilateral trading on values of individual performance measures.

Effect of early fenceline exposure to estrous ewes on the sexual performance of yearling rams

Previous research has demonstrated that early heterosexual (mating) experience improves the sexual performance of yearling rams. The present study examines the effect of early fenceline (FL) contact of young ram lambs with estrous females on their sexual performance as yearlings. A total of 104 rams, 7–8 months of age, were given either no contact (NC), direct contact (DC) or FL exposure to estrous ewes during a 3-week period in the fall breeding season. When initially tested for sexual performance as yearling rams at 18–19 months, 8 of 21 (38%) FL rams exhibited no sexual interest in estrous females (did not court or mount females), a result that was intermediate to and not significantly different from ( P>0.05) the incidence of sexual disinterest exhibited by NC (59%) and DC rams (15%). The difference between NC and DC rams was significant ( P<0.002). In addition, 12 of 21 (57%) yearling FL rams initially mounted estrous ewes, a result that was intermediate to and not significantly different from ( P>0.05) the incidence of mounting by NC and DC males (41% vs. 85%, respectively). Again, NC and DC rams differed from one another ( P<0.002). Treatment did not affect frequencies of mounting with and without ejaculation by the sexually active rams ( P=0.11 and 0.36, respectively). FL rams that were sexually inactive in year 2 spent less time ( P<0.02) in year 1 within a body length of the fence separating them from the ewes than FL rams that were sexually active in year 2. FL proximity scores in year 1 were positively correlated ( r s=0.49; P<0.05) with ejaculation frequencies in year 2. It was concluded that early FL contact with ewes only partially substitutes for direct heterosexual (mating) experience in enhancing the sexual performance of yearling rams. Also, measures of FL proximity to estrous ewes can serve as an aid in predicting relative levels of sexual performance in rams.

Car fuel-type choice under travel demand management and economic incentives

Future levels of vehicle air pollution in urban areas will depend on the proportion of new car buyers who opt for less polluting vehicles, as these appear on the market. This paper examines the factors likely to influence the demand for lower emission and zero emission vehicles. Using a discrete choice experiment, suburban driver commuters choose between three types of vehicle, one conventional, one fuel-efficient and one electric. Each is characterized by varying vehicle cost and performance measures, range and refueling rates, and commuting costs and times. The latter are manipulated to determine how their use as economic instruments might influence vehicle choice. All cost and time variables are expressed as ratios of the respondent’s current situation. Parameters of a multinomial discrete choice model are used in a choice simulator to estimate the average choice probability of each type of vehicle under different scenarios reflecting possible future relative vehicle prices and performance levels as well as differential commuting costs and times based on policies aimed at encouraging the purchase of cleaner vehicles. The evidence is that the latter economic instruments will have modest effects on vehicle choice. By contrast there would be a large shift of demand to cleaner and zero-emission vehicles provided their cost and performance came within an acceptable range of conventional vehicles.

Relative Ability, Paths of Relevance, and Influence in Task-Oriented Groups

In task-oriented groups, people accept influence more from others whom they believe, on the basis of diffuse and specific status characteristics as well as prior performances, to have greater ability at the task. Past research has treated difference in ability as a binary variable (better or worse); it is not known whether magnitude of difference in performances translates into relative magnitude of inferred ability, and thence into degrees of differentiation in the status structure of decision-making groups. We conducted an experiment to examine the relative impact of three aspects of task performance on the inference of ability: absolute level of performance, relative performance (better/worse), and the degree of difference in performances by two group members. These variables then were used to predict acceptance of influence in a two-person decision task. Simple binary difference in ability explained 35 per cent of the variance in influence accepted. Degree of difference in ability significantly increased level of prediction, particularly for subjects in the lower range of performance scores, thus supporting the claim that relative and absolute levels of performance create additional differences in expectations. Finally, we propose that a concept of graded status characteristics should be incorporated into status characteristics theory.

No transfer of perceptual learning between similar stimuli in the same retinal position

Background: Recent experiments have demonstrated a remarkable amount of specificity in the learning of simple visual tasks in humans, as well as considerable plasticity of receptive fields in the visual cortex of adult monkeys. Here, we tested the specificity of improvement through learning in the performance of human observers on two tasks using almost identical stimuli.Results Two groups, of six observers each, were trained in two hyperacuity tasks – three-dot bisection and three-dot vernier discrimination. The groups started with different tasks, and switched tasks after one hour of training. Training improved performance significantly, in spite of considerable variability between observers, but improvement did not generalize from one of these tasks to the other. This result indicates that perceptual learning can be extremely stimulus specific, and that deviations from the same standard but in orthogonal directions require completely new training.Conclusion Learning is not based on the development of a more exact map of positional information, or on training to fixate or accommodate the eye, but on a better discrimination between the stimuli using one specific stimulus dimension. We also demonstrate that observers differ considerably, not only in their speed of learning, but also in their relative level of performance on the two similar tasks.

Mechanisms of Localized Vibration Control in Complex Structures

This paper describes a numerical study of mechanisms for controlling all six degrees of freedom in localized areas of a complex structure. In localized vibration control, the controller attempts to stabilize one or more localized areas on the structure rather than attempting to stabilize the entire structure. The relative performance levels of different control strategies are evaluated by examining a frequency-dependent disturbance rejection property. A flat plate supported by two box girders is used as an example realistic structure. Plant dynamics from a finite-element model are used to draw general conclusions regarding the mechanisms by which localized vibration control is exerted.

An Isolated Structural System Using Localized Vibration Control

This paper describes an approach to actively isolate vibration of a complex structural system by controlling six degrees of freedom in its support areas. The controller attempts to stabilize only localized areas near where the structure is supported rather than attempting to stabilize the entire structure. Actuator/sensor placement and model reduction are discussed, and the specific controller design and performance measure are described. The relative performance levels of different control strategies are evaluated by examining a frequency-dependent disturbance rejection property. Concepts are illustrated by numerically simulating a complex structural system comprising a flat plate supported by two box girders; plant dynamics are obtained from a finite-element model. Conclusions are drawn regarding the mechanisms by which localized vibration control is exerted.

EVOLUTION OF SPRINT SPEED IN LACERTID LIZARDS: MORPHOLOGICAL, PHYSIOLOGICAL, AND BEHAVIORAL COVARIATION

Organismal performance abilities occupy a central position in phenotypic evolution; they are determined by suites of interacting lower-level traits (e.g., morphology and physiology) and they are a primary focus of natural selection. The mechanisms by which higher levels of organismal performance are achieved during evolution are therefore fundamentally important for understanding correlated evolution in general and coadaptation in particular. Here we address correlated evolution of morphological, physiological, and behavioral characteristics that influence interspecific variation in sprint speed in a clade of lacertid lizards. Phylogenetic analyses using independent contrasts indicate that the evolution of high maximum sprinting abilities (measured on a photocell-timed racetrack) has occurred via the evolution of (1) longer hind limbs relative to body size, and (2) a higher physiologically optimum temperature for sprinting. For ectotherms, which experience variable body temperatures while active, sprinting abilities in nature depend on both maximum capacities and relative performance levels (i.e., percent of maximum) that can be attained. With respect to temperature effects, relative performance levels are determined by the interaction between thermal physiology and thermoregulatory behavior. Among the 13 species or subspecies of lizards in the present study, differences in the optimal temperature for sprinting (body temperature at which lizards run fastest) closely matched interspecific variation in median preferred body temperature (measured in a laboratory photothermal gradient), indicating correlated evolution of thermal physiology and thermal preferences. Variability of the preferred body temperatures maintained by each species is, across species, negatively correlated with the thermal-performance breadth (range of body temperatures over which lizards can run relatively fast). This pattern leads to interspecific differences in the levels of relative sprint speed that lizards are predicted to attain while active at their preferred temperatures. The highest levels of predicted relative performance are achieved by species that combine a narrow, precise distribution of preferred temperatures with the ability to sprint at near-maximum speeds over a wide range of body temperatures. The observed among-species differences in predicted relative speed were positively correlated with the interspecific variation in maximum sprinting capacities. Thus, species that attain the highest maximum speeds are (1) also able to run at near-maximum levels over a wide range of temperatures and (2) also maintain body temperatures within a narrow zone near the optimal temperature for sprinting. The observed pattern of correlated evolution therefore has involved traits at distinct levels of biological organization, that is, morphology, physiology, and behavior; and trade-offs are not evident. We hypothesize that this particular trait combination has evolved in response to coadaptational selection pressures. We also discuss our results in the context of possible evolutionary responses to global climatic change.

A comparison of astronomy in fifteen member countries of the organisation for economic co-operation and development

Various data are collected for 15 member countries of the Organisation for Economic Cooperation and Development (OECD) that have to do with the practising of astronomy: (1) using the report of the Astronomy expert meeting of the Megascience Forum of the OECD, the level of astronomy funding, size of the research communities, relative commitment to ground-based versus space-based astronomy, etc.; (2) from other sources the size of the population, Gross National Product and size of the total research community; (3) from the paper ofSchubert et al. (1989) data on publication and citation scores of these countries in astronomy and the total research effort (excluding social and economic sciences). Using these data the 15 countries have been ranked on: (1) the relative level of astronomy funding; (2) the relative level of performance in astronomy; (3) the correspondence between funding and performance in astronomy; (4) the relative level of performance of the total science effort; and (5) the performance in astronomy relative to that in all sciences.

The relationship between comprehension and metacomprehension ability

We investigated the relationship between the ability to comprehend text and the ability to predict future performance and to assess past performance on text. Subjects were poor at predicting performance, which may be why prediction accuracy did not relate to measures of comprehension ability. Measures of comprehension ability did relate to the accuracy with which subjects assessed their performance on tests. Better and faster comprehenders judged their relative levels of test performance over sections of text more accurately than did poorer and slower comprehenders.

Neonatal morphometrics after endurance exercise during pregnancy

This study was designed to test the hypothesis that continuation of a regular running and/or aerobics program during late pregnancy at or above 50% of preconceptional levels limits fetal growth. Accordingly, detailed neonatal morphometric data were gathered in the offspring of two groups: 77 well-conditioned recreational runners and aerobic dancers who were delivered at term after continuing their exercise regimen at or above 50% of the preconceptional level throughout pregnancy and 55 matched controls. Daily exercise performance was quantitated before conception and throughout pregnancy. Significant reductions in birth weight (-310 gm), birth weight percentile (-20), ponderal index (-0.24), its percentile (-30), and the fetoplacental weight ratio (-0.7) were seen in the offspring of the exercise group whereas crown-heel length (51.4 cm) and head circumference (35.0) were similar in the two groups. Reductions in two-site skin-fold thickness (-1.5 mm), skin-fold percentile (-30), calculated percent body fat (-5.0%), and fat mass (-220 gm) in the offspring of the exercise group confirmed the asymmetric pattern of growth restriction and indicated that approximately 70% of the difference in birth weight could be explained by the difference in neonatal fat mass. In runners, the relative level of exercise performance in the last 5 months of pregnancy explained 40% of the variability in birth weight over an 1100 gm birth weight range. We conclude that continuation of a regular aerobic or running program at or above a minimal training level during late pregnancy results in an asymmetric pattern of growth restriction that primarily impacts on neonatal fat mass.