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At least 19 recordsLinked to original sources
PubMed2006

Effects of mixing on drinking and competitive behavior of dairy calves.

Group housing provides increased access to space and social interactions for calves while reducing labor costs for producers. However, group housing necessarily requires that calves be mixed and no research to date has addressed the effects of mixing on behavior of milk-fed dairy calves. The objective of this study was to monitor the feeding and competitive behavior of individual dairy calves (n = 8) after introduction into an established group of older calves fed ad libitum by a computer-controlled milk feeder. Milk feeding was monitored for 2 d before introduction into the new group and both milk feeding and competitive behaviors were monitored for 4 d after mixing. Mean (+/- SE) milk consumption before mixing was 9.7 +/- 0.7 kg/d, dropped slightly on the day of mixing to 8.6 +/- 0.6 kg/d, but increased on d 1 to 3 after mixing to 11.1 +/- 0.3 kg/d. Calves visited the feeder less frequently on the day of mixing (6.0 +/- 1.8 visits/d) than on either the days before mixing (20.3 +/- 2.5 visits/d) or the days after mixing (25.3 +/- 6.9 visits/ d). The mean duration of feeder visits and mean milk consumption per visit increased from 4 min 15 s +/- 21 s and 0.53 +/- 0.06 kg per visit before mixing to 8 min 17 s +/- 1 min 28 s and 1.87 +/- 0.51 kg per visit on the day of mixing. Competitive displacements from the milk-feeding stall were rare. In summary, feeding behavior of young calves is altered on the day of mixing, but calves are able to maintain milk intake when using a milk feeder fitted with a stall that prevents calves from displacing one another.

Aggression↗
PubMed1999

Competitive behavior in local physician markets.

Competition often is viewed as a mechanism for controlling cost. Competition may work well in urban areas with many providers; competition may not exist in rural areas with few providers. The authors use the empirical framework developed by Bresnahan and Reiss to analyze the entry behavior of physicians into local markets to determine the level of physician supply consistent with competitive behavior. The study estimates entry patterns for total and specialty physicians located in nonmetropolitan health service areas using longitudinal data. The authors find a surprising drop in the population increments necessary for entry by the second provider, possibly due to the unattractiveness of being the solo physician in an area. Subsequent population increments stabilize at three to five physicians. Since more than 93 percent of the U.S. population lives in areas that can support three to five physicians, competition between physicians through mechanisms such as managed care may be feasible.

Catchment Area, Health↗
PubMed1990

Type A behavior, competitive achievement-striving, and cheating among college students.

The present study examined the cheating behavior in competitive and noncompetitive situations of 40 college students classified as Type A (16 women, 24 men) and 40 as Type B (19 women, 21 men). Type A-scoring students were more likely to cheat than Type B-scoring students irrespective of competition. The results suggest that in some situations, especially where expectations for success cannot be met, Type A-scoring students may cheat to achieve success.

Achievement↗
PubMed1993

Influence of organic nutrients and cocultures on the competitive behavior of 1,2-dichloroethane-degrading bacteria.

The effects of organic nutrients and cocultures on substrate removal by and competitive behavior of 1,2-dichloroethane-degrading bacteria were investigated. Xanthobacter autotrophicus GJ10 needed biotin for optimal growth on 1,2-dichloroethane. In continuous culture, dilution of biotin to a concentration below 0.2 nM resulted in washout. Growth could be restored by inoculation with the 2-chloroethanol utilizer Pseudomonas sp. strain GJ1, leading to a new steady state in which about 1% of the mixed culture consisted of cells of strain GJ1. This indicates that strain GJ1 excreted biotin or a precursor for its synthesis. Inoculation of the mixed culture with Ancylobacter aquaticus AD25 did not result in washout of strain GJ10, although strain AD25 has a 10-fold-lower Ks for growth on 1,2-dichloroethane. Strain AD25 did not become dominant because of the lack of vitamins, which are necessary for its optimal growth. The results indicate that medium composition and the presence of other species strongly influence the effect of substrate limitation on the composition of a bacterial population that degrades a xenobiotic compound in a continuous culture.

Air Pollutants↗
PubMed1986

Competitive behavior of multiple, discrete B-Z transitions in supercoiled DNA.

Conformational transitions in topologically constrained duplex DNA necessarily affect and are affected by other transitional processes throughout the entire molecule. This conformational interdependence of discrete sequences within a given superhelical domain arises through a requisite competition for the free energy of supercoiling. Here we present a generalized statistical mechanical analysis of multiple, competing conformational equilibria in superhelical DNA. This model has been applied, using experimentally determined parameters, to the energetic coupling of two independent B-Z transitions. Specifically, we have monitored the extent of B-Z transition, as a function of negative superhelicity, in topoisomers of a plasmid containing two identical d(C-G)n inserts using two-dimensional gel electrophoresis. The theoretical results were found to be in good agreement with the experimental data, and we have used this model to predict the competitive behavior of B-Z transitions within sequences differing in length and sequence composition. This competition is shown to have a profound effect upon the B-Z equilibria of those sequences analyzed, resulting in a complex modulation in the extent of Z-DNA formation as a function of negative superhelicity. These theoretical and experimental results show that DNA sequences separated by large distances are capable of communicating structural information.

DNA↗
PubMed1998

Effect of trichloroethylene on the competitive behavior of toluene-degrading bacteria.

The influence of trichloroethylene (TCE) on a mixed culture of four different toluene-degrading bacterial strains (Pseudomonas putida mt-2, P. putida F1, P. putida GJ31, and Burkholderia cepacia G4) was studied with a fed-batch culture. The strains were competing for toluene, which was added at a very low rate (31 nmol mg of cells [dry weight] h). All four strains were maintained in the mixed culture at comparable numbers when TCE was absent. After the start of the addition of TCE, the viabilities of B. cepacia G4 and P. putida F1 and GJ31 decreased 50- to 1,000-fold in 1 month. These bacteria can degrade TCE, although at considerably different rates. P. putida mt-2, which did not degrade TCE, became the dominant organism. Kinetic analysis showed that the presence of TCE caused up to a ninefold reduction in the affinity for toluene of the three disappearing strains, indicating that inhibition of toluene degradation by TCE occurred. While P. putida mt-2 took over the culture, mutants of this strain which could no longer grow on p-xylene arose. Most of them had less or no meta-cleavage activity and were able to grow on toluene with a higher growth rate. The results indicate that cometabolic degradation of TCE has a negative effect on the maintenance and competitive behavior of toluene-utilizing organisms that transform TCE.

Journal Article↗
PubMed1982

Competitive behavior in male, female, and pseudohermaphroditic female dogs.

Male, spayed female, and pseudohermaphroditic female dogs were tested in pairs for competition over a large bone. Pseudohermaphroditic females had been exposed to testosterone proprionate before and immediately after birth. Two types of tests were used. In equal opportunity tests (EO tests), both members of a pair had equal chance to seize the bone when it was tossed into the arena. Each EO test was followed by an established possession test (EP test). During an EP test, the loser of the preceding EO test was given possession of the bone before the former winner was returned to the test arena. Every dog was tested against all other members of its own and both of the other groups. Males won 78 of 100 EO tests against normal females but only 61 of 100 against pseudohermaphroditic females. Pseudohermaphroditic females won 70 of 100 EO tests against normal females. When either normal or pseudohermaphroditic females were given possession of the bone in EP tests they were equally ineffective in defense against male challengers, losing 75% and 71% of their tests, respectively. Both types of females were much more successful in defending possession during EP tests against each other than they had been against males. When normal and pseudohermaphroditic females were treated with testosterone propionate, their performance in competition tests was not altered. Androgenic stimulation before and immediately after birth permanently modified the social behavior of pseudohermaphroditic females as well as the behavior of males and normal females toward the experimental dogs. However, the changes could not appropriately be described as "masculinization." Developmentally androgenized females differed from members of their own sex, but they differed just as greatly from normal males.

Animals↗
PubMed1994

Shortcomings of the behavioral competition theory of contrast: Reanalysis of McLean (1992).

McLean (1992) presented significant data showing that the occurrence of behavioral contrast in a multiple schedule was correlated with shifts in the frequency of reinforcers from a second source between components of the schedule, and interpreted his results as showing that contrast was due to changes in the degree of response competition within the constant component of the multiple schedule. Reanalysis of his data shows that there was an effect of reinforcement in the alternative component of the schedule independent of the shifts in reinforcers between components. Thus, the effect of relative rate of reinforcement cannot be ascribed, at least entirely, to the mechanisms proposed by the behavioral competition theory of contrast.

Journal Article↗
PubMed2003

Effects of diazepam and flumazenil on food competition behavior in high- and low-aggression pigeons.

The food competition interaction test performed with food-restricted pigeons with previously consolidated dominance is a useful tool for the study of offensive and defensive social aggression. In the present study, we examined the effect of GABA-A-benzodiazepine (BZD) receptor manipulation on aggression, emotion, feeder control, and eating behavior in high- and low-aggression female pigeons maintained at 80% of their normal weight and exposed to food competition interactions. The pigeons were divided into pairs by previously ranked high-aggression females (total time spent in aggression over 60 s/5 min; n=6 pairs) and low-aggression females (time spent in aggression less than 10 s/5 min; n=6 pairs). In Experiment 1, a pigeon in each pair of high- and low-aggression subjects were treated daily with an oral dose of diazepam (DZP, 0.6 mg/kg/0.3 ml) for 8 days. The other animal received the vehicle. On Day 8, food competition trials (10 min) were performed 30 min after treatments. In Experiment 2, pigeons were injected subcutaneously with flumazenil (FZL, 0.1 mg/kg/1 ml) or saline and exposed to a food competition trial 30 min after injections. In Experiment 3, one animal in each pair received DZP for 8 days. The other animal received the vehicle. On Day 8, the DZP-treated subjects were injected subcutaneously with FZL (0.1 mg/ kg/1 ml) 30 min before the oral dose of DZP. Trials were performed 30 min after DZP or vehicle administration. In Experiment 1, it was found that the DZP group of high-aggression pigeons showed lower scores of aggression (P<.05) and emotional responses (P<.05) than controls. The other group-scored behaviors were not affected. The DZP low-aggressions, however, showed scores of aggression eightfold higher than their controls (P<.05) but the other scored behaviors were not changed. In Experiment 2, FZL injection did not induce intrinsic effects on aggression either in the high- or in the low-aggression group. Experiment 3 showed that the emotional and aggressive responses to DZP were neutralized by FZL. This shows that GABA-A-BZD receptor mechanisms are implicated in the DZP responses in high- and low-aggression pigeons.

Aggression↗
PubMed1996

Memory for and experience of differential competitive behavior of individuals and groups.

Four experiments investigated whether differential experiences with groups and individuals led to previously obtained results of greater competitive expectations in intergroup than interindividual relations. In Experiment 1, participants rated their recalled instances of intergroup relations as more competitive than their interindividual relations. In Experiment 2, a relatively greater proportion of competitive to cooperative intergroup relations were recalled compared with interindividual relations. In Experiment 3, participants recorded relevant interactions for 7 days, and rated their intergroup relations as more competitive than their interindividual relations. In Experiment 4, participants recorded a relatively greater number of cooperative than competitive relations with individuals than with groups. These results can be interpreted as a demonstration in a nonlaboratory context that intergroup relations are more competitive than interindividual relations.

Adolescent↗