Frequency-dependent social dominance in a color polymorphic cichlid fish

A mechanism commonly suggested to explain the persistence of color polymorphisms in animals is negative frequency-dependent selection. It could result from a social dominance advantage to rare morphs. We tested for this in males of red and blue color morphs of the Lake Victoria cichlid, Pundamilia. Earlier work has shown that males preferentially attack the males of their own morph, while red males are more likely to win dyadic contests with blue males. In order to study the potential contribution of both factors to the morph co-existence, we manipulated the proportion of red and blue males in experimental assemblages and studied its effect on social dominance. We then tried to disentangle the effects of the own-morph attack bias and social dominance of red using simulations. In the experiment, we found that red males were indeed socially dominant to the blue ones, but only when rare. However, blue males were not socially dominant when rare. The simulation results suggest that an own-morph attack bias reduces the social dominance of red males when they are more abundant. Thus, there is no evidence of symmetric negative frequency-dependent selection acting on social dominance, suggesting that additional fitness costs to the red morph must explain their co-existence.

Determination of Language Dominance: Wada Test and fMRI Compared Using a Novel Sentence Task

This study aimed to develop a new linguistic based functional magnetic resonance imaging (fMRI)-sentence decision task that reliably detects hemispheric language dominance.

Appropriateness of reporting statistical results in orthodontics: the dominance of P values over confidence intervals

The purpose of this study was to search the orthodontic literature and determine the frequency of reporting of confidence intervals (CIs) in orthodontic journals with an impact factor. The six latest issues of the American Journal of Orthodontics and Dentofacial Orthopedics, the European Journal of Orthodontics, and the Angle Orthodontist were hand searched and the reporting of CIs, P values, and implementation of univariate or multivariate statistical analyses were recorded. Additionally, studies were classified according to the type/design as cross-sectional, case-control, cohort, and clinical trials, and according to the subject of the study as growth/genetics, behaviour/psychology, diagnosis/treatment, and biomaterials/biomechanics. The data were analyzed using descriptive statistics followed by univariate examination of statistical associations, logistic regression, and multivariate modelling. CI reporting was very limited and was recorded in only 6 per cent of the included published studies. CI reporting was independent of journal, study area, and design. Studies that used multivariate statistical analyses had a higher probability of reporting CIs compared with those using univariate statistical analyses. Misunderstanding of the use of P values and CIs may have important implications in implementation of research findings in clinical practice.

Determination of hemispheric dominance with mental rotation using functional transcranial Doppler sonography and FMRI

the aim of this study was to investigate specific activation patterns and potential gender differences during mental rotation and to investigate whether functional magnetic resonance imaging (fMRI) and functional transcranial Doppler sonography (fTCD) lateralize hemispheric dominance concordantly.

Intramyocellular lipid stores increase markedly in athletes after 1.5 days lipid supplementation and are utilized during exercise in proportion to their content

Intramyocellular lipids (IMCL) and muscle glycogen provide local energy during exercise (EX). The objective of this study was to clarify the role of high versus low IMCL levels at equal initial muscle glycogen on fuel selection during EX. After 3 h of depleting exercise, 11 endurance-trained males consumed in a crossover design a high-carbohydrate (7 g kg(-1) day(-1)) low-fat (0.5 g kg(-1) day(-1)) diet (HC) for 2.5 days or the same diet with 3 g kg(-1) day(-1) more fat provided during the last 1.5 days of diet (four meals; HCF). Respiratory exchange, thigh muscle substrate breakdown by magnetic resonance spectroscopy, and plasma FFA oxidation ([1-(13)C]palmitate) were measured during EX (3 h, 50% W (max)). Pre-EX IMCL concentrations were 55% higher after HCF. IMCL utilization during EX in HCF was threefold greater compared with HC (P < 0.001) and was correlated with aerobic power and highly correlated (P < 0.001) with initial content. Glycogen values and decrements during EX were similar. Whole-body fat oxidation (Fat(ox)) was similar overall and plasma FFA oxidation smaller (P < 0.05) during the first EX hour after HCF. Myocellular fuels contributed 8% more to whole-body energy demands after HCF (P < 0.05) due to IMCL breakdown (27% Fat(ox)). After EX, when both IMCL and glycogen concentrations were again similar across trials, a simulated 20-km time-trial showed no difference in performance between diets. In conclusion, IMCL concentrations can be increased during a glycogen loading diet by consuming additional fat for the last 1.5 days. During subsequent exercise, IMCL decrease in proportion to their initial content, partly in exchange for peripheral fatty acids.

Overweight children have a greater proportion of fat mass relative to muscle mass in the upper limbs than in the lower limbs: implications for bone strength at the distal forearm

BACKGROUND: The influence of adiposity on upper-limb bone strength has rarely been studied in children, despite the high incidence of forearm fractures in this population. OBJECTIVE: The objective was to compare the influence of muscle and fat tissues on bone strength between the upper and lower limbs in prepubertal children. DESIGN: Bone mineral content, total bone cross-sectional area, cortical bone area (CoA), cortical thickness (CoTh) at the radius and tibia (4% and 66%, respectively), trabecular density (TrD), bone strength index (4% sites), cortical density (CoD), stress-strain index, and muscle and fat areas (66% sites) were measured by using peripheral quantitative computed tomography in 427 children (206 boys) aged 7-10 y. RESULTS: Overweight children (n = 93) had greater values for bone variables (0.3-1.3 SD; P < 0.0001) than did their normal-weight peers, except for CoD 66% and CoTh 4%. The between-group differences were 21-87% greater at the tibia than at the radius. After adjustment for muscle cross-sectional area, TrD 4%, bone mineral content, CoA, and CoTh 66% at the tibia remained greater in overweight children, whereas at the distal radius total bone cross-sectional area and CoTh were smaller in overweight children (P < 0.05). Overweight children had a greater fat-muscle ratio than did normal-weight children, particularly in the forearm (92 +/- 28% compared with 57 +/- 17%). Fat-muscle ratio correlated negatively with all bone variables, except for TrD and CoD, after adjustment for body weight (r = -0.17 to -0.54; P < 0.0001). CONCLUSIONS: Overweight children had stronger bones than did their normal-weight peers, largely because of greater muscle size. However, the overweight children had a high proportion of fat relative to muscle in the forearm, which is associated with reduced bone strength.

Vaccination of cystic fibrosis patients against Pseudomonas aeruginosa reduces the proportion of patients infected and delays time to infection

INTRODUCTION: Cystic fibrosis (CF) almost always leads to chronic airway infection with Pseudomonas aeruginosa. Despite advances in antibiotic therapy, after chronic infection rapid deterioration in lung function occurs, increasing morbidity and mortality. Prevention of infection by vaccination is desirable, but earlier trials produced disappointing results. The promising short term immunogenicity and safety of a new P. aeruginosa vaccine prompted us to evaluate its long term efficacy. We conducted a 10-year retrospective analysis of outcomes in a group of vaccinated patients. MATERIALS AND METHODS: In 1989-1990, 30 young children with CF, mean age 7 years, with no prior history of infection with P. aeruginosa, were vaccinated against P. aeruginosa with a polyvalent conjugate vaccine. We report the follow-up of 26 of these patients from 1989 to 2001. The patients were given yearly vaccine boosters. Comparisons were made with a CF patient control group matched for gender, age and, where possible, genetic mutation. Vaccinated patients and controls were attending a single CF clinic and received the same clinical management throughout the study period. Main outcomes were time to infection, proportion of patients infected, development of P. aeruginosa mucoid phenotype, lung function and body weight. RESULTS: The time to infection with P. aeruginosa was longer in the vaccination group than in the control group, and fewer vaccinated patients than controls became chronically infected (32% versus 72%; P < 0.001). The proportion of mucoid infections was higher in the control group (44%) than in the vaccinated group (25%). Patients >/=18 years of age at the end of the study had a lower mean forced expiratory volume at 1 s (FEV1) than did those 13-17 years of age, but this difference was small in the vaccinated group (73.6% versus 83.7%) compared with the controls (48.0% versus 78.7%). In the >/=18 year age category the mean FEV1% at 10 years was 73.6% (vaccinated) and 48.0% (controls) (P < 0.05). In the vaccinated group only 11 (44%) of 25 patients were underweight at the 10-year follow-up compared with 18 (72%) of 25 at the beginning of the study. In the control group 17 (68%) of 25 patients were underweight at 10-year follow-up compared with 16 (64%) of 25 at the beginning of the study. CONCLUSION: Regular vaccination of young CF patients for a period of 10 years with a polyvalent conjugate vaccine reduced the frequency of chronic infection with P. aeruginosa. This was associated with better preservation of lung function. Vaccinated patients gained more weight during the study period, a possible indication of an improved overall health status.

Behavioral dominance between female color morphs of a Lake Victoria cichlid fish

Species that exhibit genetic color polymorphism are suitable for studying the evolutionary forces that maintain heritable phenotypic variation in nature. Male color morphs often differ in behavioral dominance, affecting the evolution of color polymorphisms. However, behavioral dominance among female color morphs has received far less attention. We studied a polymorphic population of the cichlid fish Neochromis omnicaeruleus from Lake Victoria, in which 3 distinct female color morphs coexist, black-and-white blotched (WB), orange blotched (OB), and plain (P) color morphs. First, we investigated dominance relationships among female morphs using triadic and dyadic encounters in the laboratory. In triadic encounters, both WB and OB females dominated plain, whereas WB females dominated OB females. Dominance of WB over OB was confirmed using dyadic encounters. In a second experiment, blotched (WB or OB) and plain full-sib sisters were bred by crossing a blotched and a plain parent. In dyadic encounters, WB female morphs dominated their plain sisters, suggesting that dominance of WB females is a pleiotropic effect of color or that genes coding for color and those influencing behavioral dominance are genetically linked, explaining the association between color and behavioral dominance despite gene flow. We conclude that behavioral dominance asymmetries exist among female color morphs of the fish N. omnicaeruleus, and discuss possible mechanisms that may account for the tight association between color and behavioral dominance.

How do subordinate and dominant species in semi-natural mountain grasslands relate to productivity and land-use change?

Changes in agricultural practices of semi-natural mountain grasslands are expected to modify plant community structure and shift dominance patterns. Using vegetation surveys of 11 sites in semi-natural grasslands of the Swiss Jura and Swiss and French Alps, we determined the relative contribution of dominant, subordinate and transient plant species in grazed and abandoned communities and observed their changes along a gradient of productivity and in response to abandonment of pasturing. The results confirm the humpbacked diversity–productivity relationship in semi-natural grassland, which is due to the increase of subordinate species number at intermediate productivity levels. Grazed communities, at the lower or higher end of the species diversity gradient, suffered higher species loss after grazing abandonment. Species loss after abandonment of pasturing was mainly due to a higher reduction in the number of subordinate species, as a consequence of the increasing proportion of dominant species. When plant biodiversity maintenance is the aim, our results have direct implications for the way grasslands should be managed. Indeed, while intensification and abandonment have been accelerated since few decades, our findings in this multi-site analysis confirm the importance of maintaining intermediate levels of pasturing to preserve biodiversity.