Quantitative imaging of concentrated suspensions under flow

We review recent advances in imaging the flow of concentrated suspensions, focussing on the use of confocal microscopy to obtain time-resolved information on the single-particle level in these systems. After motivating the need for quantitative (confocal) imaging in suspension rheology, we briefly describe the particles, sample environments, microscopy tools and analysis algorithms needed to perform this kind of experiments. The second part of the review focusses on microscopic aspects of the flow of concentrated model hard-sphere-like suspensions, and the relation to non-linear rheological phenomena such as yielding, shear localization, wall slip and shear-induced ordering. Both Brownian and non-Brownian systems will be described. We show how quantitative imaging can improve our understanding of the connection between microscopic dynamics and bulk flow.Comment: Review on imaging hard-sphere suspensions, incl summary of methodology. Submitted for special volume 'High Solid Dispersions' ed. M. Cloitre, Vol. xx of 'Advances and Polymer Science' (Springer, Berlin, 2009); 22 pages, 16 fig

Relações cineantropométricas e fisiológicas durante exercício incremental em esteira rolante

Testes incrementais em esteira rolante são muito utilizados para prescrição de treinamentos, havendo alterações fisiológicas e cinemáticas devido à natureza de incremento da intensidade do exercício. Contudo, a antropometria é um fator que não apresenta consenso na literatura. Neste sentido, os objetivos do presente estudo foram verificar o efeito de exercício incremental na concentração de lactato sanguíneo ([LAC]), e glicose ([GLI]), como também na frequência (FP) e amplitude de passadas (AP). Além disso, correlacionar valores de dados antropométricos (massa, altura, % de gordura) com as alterações existentes das [LAC] e [GLI]. Treze voluntários saudáveis realizaram teste incremental em esteira rolante (início a 8km/h, com incrementos de 1km/h a cada 3min até a exaustão). Antes e 3min após a realização do teste incremental foram registrados os valores de [LAC] e [GLI]. Durante cada intensidade do teste incremental foram realizadas avaliações da AP e FP por meio de filmagens no plano sagital. Como resultados, verificou-se que a [LAC] e [GLI] antes do teste incremental (1,94 ± 0,4mmol/L e 94,3 ± 7mg/dL, respectivamente) foram significantemente menores que os valores encontrados após o teste incremental (9,51 ± 2,7mmol/L e 126 ± 16mg/dL, respectivamente). Além disso, verificou-se aumento significante e gradativo da AP e FP ao longo do teste incremental. Correlações inversas e significantes (p Incremental treadmill tests are widely used for prescription of aerobic and anaerobic training. Physiological and kinematics parameters are changed by the progressive nature of this activity. However, there is no consensus on how anthropometric characteristics may affect the incremental test performance. Therefore, the aims of this study were (1) to verify the effects of the incremental treadmill test on the blood lactate concentration ([LAC]), glucose concentration ([GLU]), step frequency (SF) and step length (SL), and (2) to correlate anthropometric data (body mass, height, %body fat) to changes in [LAC] and [GLU]. Thirteen healthy males volunteered to this study and performed an incremental running test on a treadmill (start: 8 km/h, with progressive increases [1 km/h] at each three minute until exhaustion). [LAC] and [GLU] were registered before and 3 min after the incremental test performance. SF and SL were registered for each running speed by digital images at the sagital plane. As results, we verified that [LAC] and [GLU] before the incremental test (1.94 ± 0.4 mmol/L and 94.3 ± 7 mg/dL, respectively) were significantly lower (p < 0.05) than after the incremental test (9.51 ± 2.7 mmol/L and 126 ± 16. mg/dL, respectively). In addition, SF and SL presented significant increase (p < 0.05) throughout the incremental test. [LAC] presented inverse and significant correlations (p < 0.05) to height and body mass. Thus, an incremental treadmill running test affects kinematic (SF and SL) and physiological conditions (muscular fatigue, as consequence of the speed increase). Besides this, shorter and lighter subjects may present higher metabolite concentrations after this type of test

The reach of gene–culture coevolution in animals

Culture (behaviour based on socially transmitted information) is present in diverse animal species, yet how it interacts with genetic evolution remains largely unexplored. Here, we review the evidence for gene–culture coevolution in animals, especially birds, cetaceans and primates. We describe how culture can relax or intensify selection under different circumstances, create new selection pressures by changing ecology or behaviour, and favour adaptations, including in other species. Finally, we illustrate how, through culturally mediated migration and assortative mating, culture can shape population genetic structure and diversity. This evidence suggests strongly that animal culture plays an important evolutionary role, and we encourage explicit analyses of gene–culture coevolution in nature.Peer reviewe