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PubMed2003

[Competitive RT-PCR assay for quantification of GPI-PLD gene expression].

OBJECTIVE: To establish a competitive reverse transcription-polymerase chain reaction (RT-PCR) assay to quantify the expression of glycosylphosphatidylinositol specific phospholipase D (GPI-PLD) gene. METHODS: A competitive GPI-PLD cDNA fragment was constructed by site-directed mutagenesis by PCR method. The competitive cDNA fragment had the same primer binding sites as the target cDNA, but was 20 bp shorter in length. The competitive cDNA was transcripted into the competitive RNA in vitro as the internal standard. Then the competitive RNA was reversely transcripted and amplified together with total RNA extracted from K562 cells. The two amplified cDNA fragments could be distinguished by 10% polyacrylamide gel electrophoresis. The concentration of cellular GPI-PLD mRNA was derived from the ratio between the intensities of the bands corresponding to the amplified products. RESULTS: A 198 bp GPI-PLD competitive RNA was constructed and prepared. The competitive RNA could compete well with the target RNA in the RT-PCR reaction. The expression of GPI-PLD gene in K562 cells was (440 +/- 20) copies/ng. CONCLUSION: A competitive RT-PCR assay for the quantification of GPI-PLD gene expression may be established successfully. This method is highly sensitive, specific, and accurate.

Gene Expression Regulation, Neoplastic↗
PubMed1993

Competitive bidding for Medicare services.

One of the key issues in implementing prospective Medicare fee schedules is how to set prices that accurately reflect competitive market forces. Competitive bidding has long been used in government procurement efforts for nonhealth services. In this paper, we evaluate how provider behavior will be affected if Medicare uses competitive bidding to set Medicare fee schedules. Our model provides several important insights about competitive bidding for health care services. First, the model shows that competitive bidding will lead to 2-stage competition between providers. In the bidding stage, providers will compete to submit winning bids. In the following stage, winning providers will compete for business through marketing efforts that may enhance quality. Second, the model shows how the design of the bidding mechanism affects bidding strategies and the importance of individual provisions within the design, such as penalties for losing bidders. Third, the model demonstrates how competitive bidding will affect quality. It shows how quality may deteriorate if the bidding mechanism chooses an exclusive winner and why naming multiple winners can keep quality at acceptable levels. Finally, we identify criteria for determining whether a particular type of Medicare service is well-suited for competitive bidding.

Competitive Bidding↗
PubMedDate not supplied

Managing the managed care market competition.

Market competition among rival managed care plans has been rapidly changing the health care delivery of individual provider organizations, Local health care markets, and the American health care system. Yet, there are critical unanswered questions about managed care, and there are economic and structural problems inherent in health care markets. Thus, managed care market competition alone might not be sufficient to solve some important problems and meet the important goals of our health care system and society. Market competition, combined with some regulation to managed the competition, is more likely to achieve those goals. Market competition among managed care plans is described, and problems of this type of competition are explained in this article. One approach to managing the managed care market competition, which blends market competition with government regulation, is also presented.

Capitation Fee↗
PubMed1985

Cardiovascular changes and hearing threshold shifts in men under complex exposures to noise, whole body vibrations, temperatures and competition-type psychic load.

This study deals with changes in the temporary hearing threshold (TTS2), heart rate (HR), R-wave amplitude (RWA), diastolic blood pressure (DBP), systolic blood pressure (SBP), pulse pressure (PP) and reaction time (RT) in subjects (n = 108) who, while working on a choice reaction apparatus, were exposed in an exposure chamber to combinations of noise and vibration at dry bulb temperatures of 20 degrees and 30 degrees C. The study was carried out as a type 2-3-3 factorial experiment, the number of the exposure combinations thus being 18. To find out the effects of competition-type psychic stress, some of the subjects were placed in a competitive group and some in a non-competitive group. The members of the competitive group were given financial encouragement and information on their progress during the test, whereas those in the non-competitive group worked at the rate they considered best without any monetary rewards or interim information. The noise classes were: no noise, a stable broadband (bandwidth 0.2-16.0 kHz) A-weighted noise of 90 dB not related to competition, and a stable broadband A-weighted noise of 90 dB related to competition about the fastest reaction time. The vibration classes were: no vibration, sinusoidal whole body vibration (Z-axis) at a frequency of 5 Hz, and stochastic broadband (bandwidth 2.8-11.2 Hz) whole body vibration (Z-axis). The acceleration (rms) of both vibrations was 2.12 m/s2. One experiment consisted of a control period of 30 min, three consecutive exposure periods of 16 min with an interval of 4 min, and a 15-min recovery period. The variance analysis model best explained the variation in TTS2 values at 4 kHz and second best the variation in TTS2 values at 6 kHz; it explained the variation in HR values third best, the variation in SBP values fourth best and the variation in PP values fifth best. On the other hand, the model explained least well the variation in DBP and RWA values. In general, the explanatory power of the model increased together with the number of exposures. The psychic stress caused by competition accelerated the growth of the TTS2 values, HR values and SBP values, when the subjects were simultaneously exposed to noise or to a combination of noise and vibration. An interesting finding for the continuation of the research project was that sinusoidal and stochastic vibration affected the cardiovascular changes, temporary hearing threshold and reaction times in different ways.

Adolescent↗
PubMed1990

Chlorophyll fluorescence measurements to assess the competition of substituted anthraquinones for the QB binding site.

As analogs of the Photosystem II plastoquinone electron acceptor, QB, substituted quinones compete with QB for a common binding domain and thereby inhibit QB function. Substituted quinones interact with the QB binding niche via hydrogen bonds, and the extent of hydrogen bond formation is determined by quinone structure. We have previously shown that the quinone inhibitory activity can be quantitated using measurements of chlorophyll fluorescence quenching. To assess competition for the QB binding site, we report here measurements of the action of various pairs of substituted anthraquinones on the chlorophyll fluorescence emission of barley chloroplasts. The degree of competition between quinones for the QB binding site is classified as competition, partial competition, or no competition. Two quinones were classified as undergoing competition, i.e., interacting for the same or overlapping sites, if the chlorophyll fluorescence level in the presence of the two quinones was not as low as that achieved in the presence of either one of the quinones individually. Non-competitive quinones with different binding sites quenched chlorophyll fluorescence to the level expected if the quenching effects of the individual quinones were additive. Partial competition, or some interaction for the same or overlapping sites, was characterized by an extent of fluorescence quenching in the presence of two quinones that was more effective than either quinone alone but not as sizable as that expected when the two quinones act independently. These results reflect an interesting situation whereby substitution patterns can alter the binding characteristics within a single class of inhibitors. In an accompanying manuscript we report the results of CNDO molecular orbital calculations to demonstrate that the pi charge distribution in substituted quinones governs their binding properties.

Anthraquinones↗
PubMed1989

Competitive experience activates testosterone-dependent social aggression toward unfamiliar males.

Male hooded rats (350 to 450 g) were castrated and given subcutaneous implants of testosterone-filled or empty Silastic tubes. Four weeks later, half of the animals with testosterone implants were housed with an animal with an empty implant and left for 6 weeks. The other animals were adapted to a food-deprivation schedule, housed in testosterone-implant/sham-implant pairs and given a series of food-competition tests. Following the competition tests, all animals were observed individually in their living cage for aggression toward an unfamiliar intruder. Within the competitive situation, animals with testosterone implants were more aggressive and more successful at maintaining access to food than their cagemates with sham implants. In the unfamiliar intruder test, animals with testosterone implants that had been subjected to food competition were more aggressive toward an unfamiliar intruder than were animals with testosterone implants that had not been given competitive experience. Animals with testosterone implants given competitive experience were more aggressive than their castrated cagemates, but animals with testosterone implants not given competitive experience were not more aggressive than their cagemates. These results demonstrate that testosterone-dependent social aggression fostered by a competitive situation is elicited by an unfamiliar male intruder. They also confirm other evidence that activation of social aggression does not appear to require increased testicular testosterone secretion.

Aggression↗
PubMed2004

Competition landscapes: scaling up local biotic and abiotic processes in heterogeneous environments.

I present a model based on benthic populations by first defining a competition landscape where competitive interactions are confined to small areas, defined by the distribution of resource renewal from a global pool. Using truncated kernels and results from 1-dimensional percolation theory, I then derive an approximation allowing the scaling up of local interactions among individuals to patch and landscape levels. This approximation is used to explore how spatially structured habitats can affect competition intensity. The competition landscape is then compared to a simulation of mussel colonization under various flow velocity patterns, and is shown to predict the qualitative effect of the scale of patchiness in habitat quality on total competition intensity. The interaction between large scale hydrodynamic forcing and local competition is also shown to provide an alternate hypothesis explaining the observed among-year reversal of the relationship between topographic scale and mussel abundance in some intertidal communities. The model more generally highlights the nonlinear scaling up of competitive interactions in competition landscapes, and provides a framework for the study of self-organization in heterogeneous ecosystems.

Cluster Analysis↗
PubMed1999

Interaction of anisatin with rat brain gamma-aminobutyric acidA receptors: allosteric modulation by competitive antagonists.

Anisatin, a toxic sesquiterpene isolated from the Japanese star anise (Illicium anisatum L.), competitively inhibited the specific binding of [3H]4'-ethynyl-4-n-propylbicycloorthobenzoate ([3H]EBOB), a non-competitive antagonist of gamma-aminobutyric acid (GABA)A receptors, to rat brain membranes with an IC50 value of 0.43 microM. R 5135, a competitive GABA antagonist, decreased the potency of anisatin in inhibiting [3H]EBOB binding in a negatively cooperative manner. Two other competitive antagonists, SR 95531 (gabazine) and (-)-bicuculline methiodide, had similar effects. On the other hand, R 5135 exerted little influence on the potencies of the other non-competitive antagonists tested: EBOB, picrotoxinin, isopropylbicyclophosphate, and dieldrin. Thus, anisatin was clearly different from the other non-competitive antagonists in responding to the action of competitive antagonists on (GABA)A receptors. These findings suggest that the binding region of anisatin might overlap with that of the other non-competitive antagonists, but that anisatin must interact with other specific region(s).

Affinity Labels↗
PubMed1999

Effects of competition and its outcome on serum testosterone, cortisol and prolactin.

In various species, competitive encounters influence hormonal responses in a different way depending on their outcome, victory or defeat. This study aimed to investigate the effects of sports competition and its outcome on hormonal response, comparing it with those displayed in situations involving non-effort and non-competitive effort. To this end, serum testosterone (T), cortisol (C) and prolactin (PRL) were measured in 26 judoists who participated in three sessions (control, judo fight and ergometry). The relationship between hormonal changes and psychological variables before and after the fight were also analysed. Our results showed a hormonal response to competition, which was especially characterized by an anticipatory rise of T and C. Depending on outcome, significant higher C levels were found in winners in comparison to losers through all the competition but not in T or PRL, both groups expending a similar physical effort. Furthermore, similar hormonal responses to the fight and to a non-competitive effort with the same caloric cost were found, other than with PRL. Winners showed a higher appraisal of their performance and satisfaction with the outcome, and perceived themselves as having more ability to win than losers, although there were no significant differences in motivation to win. Finally, the relationships found between T changes in competition and motivation to win, as well as between C response and self-efficacy suggest that in humans hormonal response to competition is not a direct consequence of winning and losing but rather is mediated by complex psychological processes.

Adult↗
PubMed2001

Intraspecific competition favours niche width expansion in Drosophila melanogaster.

Ecologists have proposed that when interspecific competition is reduced, competition within a species becomes a potent evolutionary force leading to rapid diversification. This view reflects the observation that populations invading species-poor communities frequently evolve broader niches. Niche expansion can be associated with an increase in phenotypic variance (known as character release), with the evolution of polymorphisms, or with divergence into many species using distinct resources (adaptive radiation). The relationship between intraspecific competition and diversification is known from theory, and has been used as the foundation for some models of speciation. However, there has been little empirical proof that niches evolve in response to intraspecific competition. To test this hypothesis, I introduced cadmium-intolerant Drosophila melanogaster populations to environments containing both cadmium-free and cadmium-laced resources. Here I show that populations experiencing high competition adapted to cadmium more rapidly than low competition populations. This provides experimental confirmation that competition in a population can drive niche expansion onto new resources for which competition is less severe.

Adaptation, Physiological↗
PubMed2005

Changes in community size affect the outcome of competition.

We examine the role of stochasticity and competitive ability in affecting competition between two species using models derived for population genetics. Just as changing population size affects the fixation of a new mutation, we show that changing the total number of competitors (i.e., community size) can alter the course of competitive exclusion across a wide range of initial starting densities of the two competing species. Shifts in competitive exclusion occur because changes in community size affect the relative importance of competitive ability and stochasticity in affecting the outcome of competition, potentially allowing inferior invaders to usurp superior residents. By shifting the role of stochasticity and competitive ability, any process that changes the total number of competitors in a habitat (e.g., disturbance, eutrophication, fragmentation, predation) may lead to shifts in competitive exclusion and the composition of communities.

Competitive Behavior↗
PubMed2000

Consistency of swimming performance within and between competitions.

PURPOSE: The consistency of performance between events impacts how athletes should specialize in events, how competitions should be structured, and how changes in performance affect an athlete's placing in an event. We have therefore determined the consistency of swimming performance in events within and between two national-level competitions. METHODS: We used mixed linear modeling to analyze official performance times of 149 male and 162 female swimmers at a junior national championship, and of 117 male and 104 female swimmers at an open national championship 20 d later. The events differed in stroke (backstroke, breaststroke, butterfly, freestyle, and individual medley) or distance (50-1500 m). RESULTS: Swimmers were most consistent in their performance for the same event between the two competitions (typical variation between competitions, 1.4%; 95% likely range of true value, 1.3-1.5%). They were less consistent between distances of a given stroke within each competition (1.7%; 1.5-1.9%) and least consistent between strokes for a given distance (2.7%; 2.3-3.1%). Variation in performance between the longest continuous freestyle distances (400, 800, and 1500 m) in the open competition was half that between widely spaced freestyle distances (50, 200, and 800 m). Faster swimmers were more consistent (1.1%; 0.9-1.4%) for the same event between competitions than slower swimmers (1.5%; 1.3-1.9%). CONCLUSIONS: (a) Swimmers are stroke specialists rather than distance specialists; with the present set of events in competitions, they should concentrate training and competing on a particular stroke rather than a particular distance. (b) More swimmers would have a chance of winning a medal if events of a given stroke differed more widely in distance. (c) Factors that affect performance time by as little as 0.5% will affect the placing of a top junior swimmer.

Adolescent↗
PubMed2025

Uncovering the genetic basis of competitiveness and the potential for cooperation in plant groups.

Crop productivity was transformed by incorporating dwarfing genes that made plants smaller and less competitive (more cooperative). Beyond such major shifts in plant size, however, it is not clear how much variation in competitiveness remains and how to find its genetic basis. We performed plant density experiments, using 484 lines of the Arabidopsis thaliana multi-parent advanced generation inter-cross population, to compare methods for mapping the genetic basis of plant competitiveness. We first found that a major dwarfing gene, the erecta allele, caused reduced competitiveness and higher group productivity. Then, measuring competitiveness more generally, we found: (i) extensive variation in generic measures of competitiveness that extended beyond the effects of the erecta allele; (ii) a novel genomic region underlying variation in competitiveness; and (iii) that some measures of competitiveness were more useful than others. Our results show how modern genomic resources, including multi-parent populations, could uncover hidden genes for more cooperative crop plants.

Arabidopsis↗
PubMed1994

Adipose tissue storage of drugs as a function of binding competition. In-vitro studies with distribution dialysis.

Distribution dialysis was used to study binding competition between homogenates of adipose tissue and of lean tissues. The concentration ratios adipose/X (X = blood, muscle, lung, liver) of eight lipophilic drugs were determined in the absence and in the presence of a competing binding system X. With drugs which do not undergo storage in adipose tissue in-vivo, yet have a high volume of distribution, such as imipramine or desipramine, there was strong binding competition, and the balance of distribution was shifted from adipose to lean tissues. In the case of indomethacin with a low volume of distribution this shift was from adipose tissue to blood. With diazepam there was a marked binding competition which was not, however, sufficient to shift the balance of distribution away from adipose tissue. Binding competition was negligible with thiopentone. In contrast, with the equally lipophilic hexethal a moderate binding competition was observed. This is consistent with a decreased adipose tissue storage of the latter barbiturate. It is concluded that binding competition exists not only between blood and tissues but also among individual tissues. It is suggested that occurrence and extent of adipose tissue storage of drugs are determined by binding competition between lean and adipose tissues and, more generally, that distribution of lipophilic drugs is largely a function of binding competition.

Adipose Tissue↗
PubMed2005

Men, muscles, and body image: comparisons of competitive bodybuilders, weight trainers, and athletically active controls.

OBJECTIVES: To investigate body image and psychosocial adjustment among competitive bodybuilders, non-competitive weight trainers, and athletically active men. METHODS: Participants were 40 men in each of the three groups who were assessed on body composition and multiple facets of body image evaluation, investment and anxiety, eating attitudes, and social self esteem. RESULTS: Relative to the other two groups, competitive bodybuilders had greater body mass due to fat-free body mass. Although groups did not differ in their situational body image discomfort, competitive bodybuilders and weight trainers had a more positive global appearance evaluation and were more psychologically invested in their physical appearance. Compared with active controls, men in both weightlifting groups were more satisfied with their upper torso and muscle tone. Competitive bodybuilders reported more mid torso satisfaction than the other two groups. Competitive bodybuilders also wished to be significantly heavier than controls did and reported higher social self esteem but greater eating disturbance. CONCLUSIONS: The findings suggest that competitive bodybuilders as a group are not more "muscle dysmorphic" than either non-competitive weight trainers or physically active men who do not train with weights.

Adult↗
PubMed1990

The nature and extent of hospital competition in a government-funded health system.

A national study of Canadian hospitals assessed the perceived level and types of competition and the strategies pursued by these hospitals. Questionnaire data were obtained from chief executive officers in 715 hospitals, yielding a national response rate of 68%. Respondents indicated the perceived level of competition in the environment, the content of competition, and stated hospital strategies. Additional data were obtained on market share and hospital type. Close to half of the respondents indicated little or no competition in their environment, while 30% indicated substantial levels of competition. This represents a significant deviation from conventional wisdom about the Canadian health services environment. Respondents in hospitals with more than 75% of the market share were less likely to perceive competition than those with a smaller market share. CEOs in teaching hospitals and in hospitals located in larger communities reported higher levels of competition. Hospitals competed mostly for capital, programs, and staff; about a third of hospitals competed for patients and no differences were found by type of institution. Those hospitals in more competitive environments were more likely to indicate the use of diversification and horizontal integration as organizational strategies.

Canada↗
PubMed2004

The effects of competition on achievement motivation in Chinese classrooms.

BACKGROUND: Laboratory studies have consistently found that competition induces performance goals and affects learning motivation. However, the ecological validity of these results is yet to be established. There is a need for investigation of whether the results hold in both the classroom context and non-Western culture. AIM: The study investigated the effects of competition on learning motivation among Chinese students in an authentic classroom setting. SAMPLE: The participants were 52 students of grade 7 from two Hong Kong secondary schools. METHOD: They were randomly assigned to either competitive or non-competitive conditions in a 2-hour Chinese typewriting course. RESULTS: Students in the competitive condition performed better in easy tasks than their counterparts in the non-competitive condition. However, they were more performance-oriented and more likely to sacrifice learning opportunities for better performance. They were also prone to have worse self-evaluation after failure. Although there were no statistically significant differences between the two conditions in task enjoyment and achievement attribution, the direction of the differences was consistently unfavourable to students in the competitive condition. CONCLUSION: The findings were consistent with the predictions of goal theory. Competitiveness induces performance goals and worse self-evaluation after failure among Chinese students in a classroom setting, as was found with Western students in a laboratory setting.

Child↗
PubMedDate not supplied

Why competition law matters to health care quality.

Competition law (encompassing both antitrust and consumer protection) is the forgotten stepchild of health care quality. This paper introduces readers to competition law and policy, describes its institutional features and analytic framework, surveys the ways in which competition law has influenced quality-based competition, and outlines some areas in need of further development. Competition law protects the competitive process--not individual competitors. It guides the structural features of the health care system and the conduct of providers as they navigate it. Competition law does not privilege quality over other competitive goals but honors consumers' preferences with respect to trade-offs among quality, price, and other attributes of goods and services.

Antitrust Laws↗