ACUTE EFFECTS OF MOVEMENT VELOCITY ON BLOOD LACTATE AND GROWTH HORMONE RESPONSES AFTER ECCENTRIC BENCH PRESS EXERCISE IN RESISTANCE-TRAINED MEN

This study aimed to compare the effects of different velocities of eccentric muscle actions on acute blood lactate and serum growth hormone (GH) concentrations following free weight bench press exercises performed by resistance-trained men. Sixteen healthy men were divided into two groups: slow eccentric velocity (SEV; n = 8) and fast eccentric velocity (FEV; n = 8). Both groups performed four sets of eight eccentric repetitions at an intensity of 70% of their one repetition maximum eccentric (1RMecc) test, with 2-minute rest intervals between sets. The eccentric velocity was controlled to 3 seconds per range of motion for SEV and 0.5 seconds for the FEV group. There was a significant difference (P < 0.001) in the kinetics of blood lactate removal (at 3, 6, 9, 15, and 20 min) and higher mean values for peak blood lactate (P = 0.001) for the SEV group (9.1 ± 0.5 mM) compared to the FEV group (6.1 ± 0.4 mM). Additionally, serum GH concentrations were significantly higher (P < 0.001) at 15 minutes after bench press exercise in the SEV group (1.7 ± 0.6 ng · mL⁻¹) relative to the FEV group (0.1 ± 0.0 ng · mL⁻¹). In conclusion, the velocity of eccentric muscle action influences acute responses following bench press exercises performed by resistance-trained men using a slow velocity resulting in a greater metabolic stress and hormone response.     

Pattern,process and geographic modes of speciation

The tradition of classifying cases of speciation into discrete geographic categories (allopatric, parapatric and sympatric) fuelled decades of fruitful research and debate. Not surprisingly, as the science has become more sophisticated, this simplistic taxonomy has become increasingly obsolete. Geographic patterns are now reasonably well understood. Sister species are rarely sympatric, implying that sympatric speciation, it its most general sense, is rare. However, sympatric speciation, even in its most restricted population genetic sense, is possible. Several case studies have demonstrated that divergence has occurred in nature without geographic barriers to gene flow. Obviously, different sets of criteria for sympatric speciation will lead to different numbers of qualifying cases. But changing the rules of nomenclature to make ‘sympatric speciation’ more or less common does not constitute scientific progress. Advances in the study of speciation have come from studies of the processes that constrain or promote divergence, and how they are affected by geography.     

Dermatoglyphics in hypertension: a review

Hypertension is a major contributor to the global burden of disease and mortality. A major medical advancement would be a better means to ascertain which persons are at higher risk for becoming hypertensive beforehand. To that end, there have been a number of studies showing that certain dermatoglyphic markers are associated with hypertension. This association could be explained if the risk toward developing hypertension later on in life is somehow connected with fetal development of dermatoglyphics. It would be highly valuable from a clinical standpoint if this conjecture could be substantiated since dermatoglyphic markers could then be used for screening out individuals who might be at an elevated risk of becoming hypertensive. The aim of this review was to search for and appraise available studies that pertain to the association between hypertension and dermatoglyphics.A systematic literature search conducted using articles from MEDLINE (PubMed), Trip, Cochran, Google scholar, and gray literature until December 2014. Of the 37 relevant publications, 17 were included in the review. The review performed according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement.This review showed a fairly consistent finding of an increased frequency of whorl patterns along with a higher mean total ridge count in digital dermatoglyphic results in hypertensive samples compared to controls. However, it was imperative to discuss several limitations found in the studies that could make this association as yet unsettled.     

Relatedness and genetic structure in a socially polymorphic population of the spider Anelosimus studiosus

The evolution of sociality remains a challenge in evolutionary biology and a central question is whether association between kin is a critical factor favouring the evolution of cooperation. This study examines genetic structure of Anelosimus studiosus, a spider exhibiting polymorphic social behaviour. Two phenotypes have been identified: an ‘asocial’ phenotype with solitary female nests and a ‘social’ phenotype with multi‐female/communal nests. To address the questions of whether these phenotypes are differentiated populations and whether cooperative individuals are closely related, we used microsatellites to analyse individuals from both communal and solitary nests. We found no evidence of differentiation between social and solitary samples, implying high rates of interbreeding. This is consistent with the hypothesis that these phenotypes coexist as a behavioural polymorphism within populations. Pairwise relatedness coefficients were used to test whether cooperating individuals are more closely related than expected by chance. Pairwise relatedness of females sharing communal webs averaged 0.25, the level expected for half‐siblings and significantly more closely related than random pairs from the population. Solitary females collected at similar distances to the communal spider pairs were also more closely related than expected by chance (mean relatedness = 0.18), but less related than social pairs. These results imply that low dispersal contributes to increase likelihood of interaction between kin, but relatedness between social pairs is not explained by spatial structure alone. We propose that these phenotypes represent stages in the evolution of sociality, where viscous population structure creates opportunities for kin selection and cooperation is favoured under certain environmental conditions.