Search results for "competition."
showing 10 items of 1367 documents
Infanticide and Population Growth in the Bank Vole (Myodes glareolus): The Effect of Male Turnover and Density
2011
One major intrinsic factor affecting recruitment of young into a population is infanticide, the killing of conspecific young by adult males. It occurs in most mammal species, like our study species the bank vole (Myodes glareolus), and is widely accepted as an adaptive behavior, which may increase male fitness via nutritional gain, decreased competition, or an increased access to mates. A turnover of males in a population increases the risk of infanticide owing to a disruption of social structures. In a controlled field study, we tested the effects of total male turnover and density on juvenile recruitment and female space use in experimental bank vole populations. Juvenile recruitment decl…
Within territory abundance of red wood ants Formica rufa is associated with the body condition of nestlings in the Eurasian treecreeper Certhia famil…
2007
Studies on individual reproductive success in relation to interspecific competition between distantly related taxa are scarce. We studied whether the abundance of red wood ants Formica rufa -group is related to the breeding habitat selection, fecundity and offspring quality in the Eurasian treecreeper Certhia familiaris, an old-growth forest passerine. The nest-box occupancy data were gathered over a five-year study period, whereas the breeding performance analyses were based on a two-year data set. The abundance of wood ants, measured within 50 m around the nest-boxes, was not related to nest-box occupancy rate, fecundity or the physiological stress of nestlings. In contrast, the abundance…
The joint emergence of group competition and within-group cooperation
2015
Abstract Between-group conflict and within-group cooperation can be seen as two sides of the same coin, coevolving in a group-structured population. There is strong support for between-group competition facilitating the evolution of human cooperative tendencies, yet our understanding of how competition arises is less clear. We show that groups of randomly assembled individuals spontaneously engage in costly group competition, and that decisions promoting between-group conflict are associated with high levels of within-group cooperation. Remarkably, when groups were given the possibility to compete against other groups, net earnings for individuals were higher than when groups were not allow…
Sperm quality, secondary sexual characters and parasitism in roach (Rutilus rutilus L.)
2004
According to sperm competition models, a male spawning in a disfavoured role should have spermatozoa with higher velocity but shorter longevity compared with a male spawning in a favoured role. Moreover, immunosuppressive androgens are needed to produce both secondary sexual characters and sperm cells. The ‘sperm protection’ hypothesis suggests that the immunosuppressive action of androgens has evolved to protect haploid spermatozoa, which are antigenic, from autoimmune attacks. Therefore, a male with high sexual ornamentation may be more susceptible to diseases but may possess better quality ejaculate than his less ornamented rival. We studied sexual ornamentation (breeding tubercles), eja…
Comparison of condensed versus noncondensed cycling test methods and correlation to a 185 minutes’ indoor race simulation
2017
Master's thesis Sports Science ME517 - University of Agder 2017 Background: The validity of a currently used condensed indoor test protocols (C-TP) as measurement of competitive cycling performance is questioned. Purpose: C-TP contain testing of wattage at lactate threshold (LTW), maximum oxygen consumption (VO2max) and a Wingate anaerobic test (WAnT), performed consecutively during one session. As comparison these tests were separated and performed individually over three consecutive days, giving a non-condensed test protocol (NC-TP). The results were compared to a 5min all-out cycling test (5min all-out) performed individually and as part of a 185 minutes’ race simulation. Method: During …
The commercialization of the sport from Sports competition Ethics
2012
La ética del deporte surge como una disciplina particular. Podemos encontrar dos lados radicalmente opuestos, el de aquellos que ven la comercialización del deporte como la corrupción del ideal de búsqueda de excelencia inherente a la práctica deportiva, son los partidarios de la «tesis de la corruptibilidad» y la de otro grupo, entre los que se encuentra Simon del «Hamilton College» en EEUU, que sostiene que la comercialización puede presentar un lado positivo éticamente aceptable siempre que se plantee como medio para alcanzar los valores internos en el deporte. En mi exposición abogaré por un enfoque aristotélico que entiende que la prudencia, no sólo comporta el conocimiento de los fine…
Individual- and group-level sex ratios under local mate competition : consequences of infanticide and reproductive dominance
2023
Extremely female-biased sex ratios of parasitoid wasps in multiple-foundress groups challenges evolutionary theory which predicts diminishing bias as foundress numbers increase. Recent theory based on foundress cooperation has achieved qualitative rather than quantitative success in explaining bias among parasitoids in the genus Sclerodermus. Here, we develop an explanation, expanding the theory of local mate competition, based on the observation that male production seems dominated by some foundresses within groups. Two sex ratio effects arise from such reproductive dominance: an immediate effect via suppression of male production, and a long-term evolutionary response to reproductive skew…
Fisiologia e patologia della fiscal competition
2017
L’articolo ha ad oggetto gli effetti della fiscal competition, analizzati sotto il duplice aspetto fisiologico e patologico del fenomeno. In primo luogo, esso evidenzia che la fiscal competition è il risvolto naturale (i) della competizione fra Stati e imprese multinazionali, (ii) della globalizzazione economica e (iii) della propensione alla sovranazionalità dei singoli ordinamenti giuridici.Pertanto, innanzitutto, la fiscal competition è sostanzialmente un fenomeno fisiologico. Tuttavia, il presente elaborato evidenzia che la fiscal competition ha effetti negativi su alcuni importanti principi: la sovranità statale, l’equità fiscale e l’efficienza generale del sistema economico. In questo…
Nitrogen uptake and nitrogen fertilizer recovery in old and modern wheat genotypes grown in the presence or absence of interspecific competition
2015
Choosing genotypes with a high capacity for taking up nitrogen (N) from the soil and the ability to efficiently compete with weeds for this nutrient is essential to increasing the sustainability of cropping systems that are less dependent on auxiliary inputs. This research aimed to verify whether differences exist in N uptake and N fertilizer recovery capacity among wheat genotypes and, if so, whether these differences are related to a different competitive ability against weeds of wheat genotypes. To this end, 12 genotypes, varying widely in morphological traits and year of release, were grown in the presence or absence of interspecific competition (using Avena sativa L. as a surrogate wee…
Offensive Transitions in High-Performance Football: Differences Between UEFA Euro 2008 and UEFA Euro 2016
2019
[Abstract] Coaches, footballers and researchers agree that offensive transitions are one of the most important moments in football today. In a sport where defense over attack dominates, with low scores on the scoreboard, the importance of these actions from the offensive point of view becomes very important. Despite this, scientific literature is still very limited on this topic. Therefore, the objectives set out in the present investigation have been two: first, by means of a proportion analysis and the application of a chisquare test, it was intended to describe the possible differences between the offensive transitions made in the UEFA Euro 2008 and UEFA Euro 2016; then, through differen…