CONTROL OF LEG STIFFNESS AND ITS EFFECT ON MECHANICAL ENERGETIC

INTRODUCTION: In normal daily activity as in sports, humans adjust their physical behavior depending on the ground surface characteristics (Farley et al., 1998; Ferris, Liang & Farley, 1999) by being able to vary their performance (Arampatzis, 1999; Sanders, 1993). A difference in surface stiffness leads to a change in leg stiffness (Farley et al., 1998; Ferris, Liang & Farley, 1999). There are published results on relationships between joint stiffness and oxygen consumption (Dalleau et al., 1998; Heise & Martin, 1993). From this research, it can be concluded that leg stiffness influences athletic performance. The relationship between leg stiffness and performance during explosive movements on a sprung surface has not been reported in the literature to date. Leg Stiffness can be influenced by stride frequency while running (Farley & Gonzalez, 1996) or hopping frequency when bouncing in place (Farley & Morgenroth, 1999). These findings support the idea that it is possible to control leg stiffness by manipulating ground contact times and to consider its effects on mechanical energetic processes during drop jumps on a sprung surface. The purpose of this study is two-fold: a. Examinations of the effect of verbal instructions, given to the subjects for the control of lower -extremity stiffness. b. Assessment of the effect of the leg stiffness on mechanical energetic processes during drop jumps on a sprung surface

Comparative analysis of foraging and habitat use by the sympatric Caribbean parrotfish Scarus vetula and Sparisoma viride (Scaridae)

On the fringing reef of Bonaire, Netherlands Antilles, a comparative study was made of habitat use, diet selection, foraging behaviour and food acquisition of the parrotfish species Scarus vetula and Sparisoma viride. The species are sympatric and live in the same reef habitats (depth zones). Both species show similar foraging selectivity, but exploit algal resources differently. Preferred food items are turf algae on substrates infested with endolithic algae, whereas crustose corallines are avoided. Foraging preferences are related to yield, i.e. the amount of AFDW (ash-free dry weight), protein and energy that can be harvested per bite. Foraging behaviour differs between the species. S. vetula takes more bites in long forays, has higher bite rates (no, of bites s(-1)), and makes fewer and smaller scars on grazing substrates than S. viride. Furthermore, S. vetula prefers flat substrate surfaces while adult S. viride graze by preference on concave surfaces. Species-specific differences in preference and utilization of grazing substrates are related to feeding mode. S. vetula employs a scraping feeding mode by which mainly epilithic algae are ingested. In contrast, S. viride is an excavating grazer that ingests large amounts of endolithic and crustose algae. Intake and assimilation of algal AFDW, protein and energy were quantified through a combination of laboratory feeding trials and field observations. S. vetula has lower food intake (mg AFDW bite(-1)) than S. viride (0.8 x 10(-3) x fish wet wt, FWW, and 2.3 x 10(-3) x FWW respectively), resulting from smaller (shallower) bites. Assimilation efficiencies of total AFDW, protein and energy by S. vetula were higher than in S. viride grazing on the same dead coral substrates, In spite of different feeding modes and different fractions of the primary production harvested, daily amounts of assimilated nutrients and energy are similar for both species, resulting from higher feeding rates (no. of bites h(-1)) and higher assimilation efficiency in S. vetula.</p

Functional Analysis of the VirSR Phosphorelay from Clostridium perfringens

Toxin production in Clostridium perfringens is controlled by the VirSR two-component signal transduction system, which comprises the VirS sensor histidine kinase and the VirR response regulator. Other studies have concentrated on the elucidation of the genes controlled by this network; there is little information regarding the phosphorelay cascade that is the hallmark of such regulatory systems. In this study, we have examined each step in this cascade, beginning with autophosphorylation of VirS, followed by phosphotransfer from VirS to VirR. We also have studied the effects of gene dosage and phosphorylation in vivo. We have used random and site-directed mutagenesis to identify residues in VirS that are important for its function and have identified a region in the putative sensory domain of VirS that appeared to be essential for function. In vitro phosphorylation studies showed that VirSc, a truncated VirS protein that lacked the N-terminal sensory domain, was capable of autophosphorylation and could subsequently act as a phosphodonor for its cognate response regulator, VirR. Conserved residues of both VirS and VirR, including the D57 residue of VirR, were shown to be essential for this process. By use of Targetron technology, we were able to introduce a single copy of virR or virRD57N onto the chromosome of a virR mutant of C. perfringens. The results showed that in vivo, when virR was present in single copy, the production of wild-type levels of perfringolysin O was dependent on the presence of virS and an unaltered D57 residue in VirR. These results provide good evidence that phosphorylation is critical for VirR function

ESCMID-ECMM guideline : diagnosis and management of invasive aspergillosis in neonates and children

ACKNOWLEDGEMENT Prof Warris is supported by the Wellcome Trust Strategic Award (grant 097377) and the MRC Centre for Medical Mycology (grant MR/N006364/1) at the University of Aberdeen. FUNDING European Society of Clinical Microbiology and Infectious Diseases (ESCMID) and the European Confederation of Medical Mycology (ECMM)Peer reviewedPostprintPostprin

Obstetric care models in the Southern Region of Brazil and associated factors

The study sought to identify obstetric care models for low-risk pregnancies in the Southern Region of Brazil and to estimate factors associated with these models and maternal and neonatal outcomes. This is a cross-sectional, hospital-based study using data from the Birth in Brazil survey regarding puerperae and newborns. We identified 2,668 low-risk pregnant women. We carried out an exploratory analysis using the proportion of practices per hospital, among them inducing labor, presence of a companion, cesarean section and skin-to-skin contact, in order to obtain the care models we called Best Practice, Interventionist I and Interventionist II. We then carried out an inferential analysis of the associated characteristics. Results show that access to public or private funding, cultural factors and actions taken by health professional are associated with the care models. Public care had different contexts, one based on public policies and evidence-based practices; and another, that suggests the intentionality of vaginal delivery without considering humanization principles. Private care, on the other hand, is standardized and centered on the medical professional, with higher intervention levels. We conclude there is a predominance of interventionist obstetric care models in the Southern Region of Brazil, a type of care that goes against the best evidence, and that women who receive care in public hospitals have greater chances of benefiting from good practices