Cognitive strategies as a function of effort in elite, average and recreational cyclists

Includes bibliographical references.The purposes of this study were two-fold; to develop a cycling-specific cognitive strategy classification system, and to investigate the differential and interactive effects of effort and competitive status, on associative strategy use in cyclists. Subjects consisted of 8 elite, 8 average, and 8 recreational cyclists (n = 24). A light weight micro-cassette recorder was used to document the subjects' verbalized thoughts while training. Effort was measured by the rating of percieved exertion (RPE), and through the recording of heart rate every 60 seconds. A cycling-specific subcategory of thought (equipment monitoring) was identified, which had not previously been identified in similar research on marathon runners. The implications of sport specific classification systems are discussed. Statistical analyses showed no support for the popular notion that cognitive strategy use varies according to competitive status. Neither did they show support for the notion that it varies according to effort. The statistically non-significant findings are discussed in the light of the stochastic nature of cycling, and recommendations are made to cater for this in future research

Computer-based training and its impact on training and education

Computer-based training is an area of training that is growing at a rapid pace. Although it is becoming more and more popular, we must determine the actual impact it has on training in order to assess its usefulness and relevance. This study was developed by researching and compiling available data on the subject of computer based training, and then forming an assessment of this type of training based on that information. It was found that computer based training offers many positive features as well as advantages and appropriate applications, but it does have its limitations, and is not the answer for all training situations. This type of training is still in its infancy, and its full impact and significance remains yet to be seen

Psychological preparation of the 2004 South African Olympic team

Background. The 2004 Athens Olympics represented the greatest opportunity for psychological preparation yet afforded a multicode South African team. A coordinating psychologist was appointed a year before the event, with access to financial and other resources. Aim. The purposes of this paper are fourfold: (i) to describe a 5-stage model used for the psychological preparation of the 2004 South African Olympic team; (ii) to report on the athletes and their management teams’ perceptions of its efficacy; (iii) to describe the perceived positive and negative determinants of these same subjects’ state of mind at the Olympics; and (iv) to make recommendations for the existing model’s further improvement. Results. The psychological preparation was well received, with almost all athletes and coaches requesting an expansion thereof in the future. Recommendations are made for the model’s improvement, particularly for its ongoing implementation throughout the 4-year Olympic cycl

Estudios arqueológicos en la región Pavas-La Cumbre

La zona de Pavas está localizad a en la vertiente de la cordillera occidental que da hacia el Pacífico. El área de la investigación comprende terrenos que políticamente pertenecen al municipio de La Cumbre, cuya cabecera se localiza a los 3º 39' latitud norte y 76º 34' longitud oeste. Pavas era la antigua cabecera del municipio, antes de la construcción del Ferrocarril del Pacífico, a principios de este siglo. En términos arqueológicos el rasgo sobresaliente son los elementos funerarios. Se puso de manifiesto la abundancia de urnas funerarias, conocidas con el nombre de urnas de Pavas (Figs. 2 y 3) que con el tiempo han venido a caracterizar esta región. Este patrón de enterramiento contrasta con los conocidos en las zonas aledañas que - con unas excepciones de entierros del período Yotoco (Bray 1981: 3)- son generalmente entierros primarios (Caldas, 1972; Wassén, 1976). Se trata de una costumbre en una área bastante delimitada, cuyo origen es aún incierto. &nbsp

The Grant Component in United States Economic Aid to Less-Developed Countries

Foreing aid, since its comparatively recent inception, continually has been the subject of polemics. Though volumes have been written concerning its rationale, implementation, burden, impact, etc., only recently, with the concept of grants economics, have asessments of economic aid on a quantitative subsify basis been possible. These pioneering efforts have led the way toward a clearer understanding of foreign aid by identifying the real transfers involved. The object of the following analysis is to ferret out the grant component of official United States economic aid to less-developed countries from 1953 to 1969. The United States is chosen due to availabiity of data and because U.S. aid historically has contirbuted over fifty percent of net global foreign aid..

Multiphysics simulation of a microfluidic perfusion chamber for brain slice physiology

Understanding and optimizing fluid flows through in vitro microfluidic perfusion systems is essential in mimicking in vivo conditions for biological research. In a previous study a microfluidic brain slice device (μBSD) was developed for microscale electrophysiology investigations. The device consisted of a standard perfusion chamber bonded to a polydimethylsiloxane (PDMS) microchannel substrate. Our objective in this study is to characterize the flows through the μBSD by using multiphysics simulations of injections into a pourous matrix to identify optimal spacing of ports. Three-dimensional computational fluid dynamic (CFD) simulations are performed with CFD-ACE + software to model, simulate, and assess the transport of soluble factors through the perfusion bath, the microchannels, and a material that mimics the porosity, permeability and tortuosity of brain tissue. Additionally, experimental soluble factor transport through a brain slice is predicted by and compared to simulated fluid flow in a volume that represents a porous matrix material. The computational results are validated with fluorescent dye experiments

Activity-regulated RNA editing in select neuronal subfields in hippocampus

RNA editing by adensosine deaminases is a widespread mechanism to alter genetic information in metazoa. In addition to modifications in non-coding regions, editing contributes to diversification of protein function, in analogy to alternative splicing. However, although splicing programs respond to external signals, facilitating fine tuning and homeostasis of cellular functions, a similar regulation has not been described for RNA editing. Here, we show that the AMPA receptor R/G editing site is dynamically regulated in the hippocampus in response to activity. These changes are bi-directional, reversible and correlate with levels of the editase Adar2. This regulation is observed in the CA1 hippocampal subfield but not in CA3 and is thus subfield/celltype-specific. Moreover, alternative splicing of the flip/flop cassette downstream of the R/G site is closely linked to the editing state, which is regulated by Ca(2+). Our data show that A-to-I RNA editing has the capacity to tune protein function in response to external stimuli

Myelinated, synapsing cultures of murine spinal cord – validation as an in vitro model of the central nervous system

Research in central nervous system (CNS) biology and pathology requires in vitro models, which, to recapitulate the CNS in vivo, must have extensive myelin and synapse formation under serum-free (defined) conditions. However, finding such a model has proven difficult. The technique described here produces dense cultures of myelinated axons, with abundant synapses and nodes of Ranvier, that are suitable for both morphological and biochemical analysis. Cellular and molecular events were easily visualised using conventional microscopy. Ultrastructurally, myelin sheaths were of the appropriate thickness relative to axonal diameter (G-ratio). Production of myelinated axons in these cultures was consistent and repeatable, as shown by statistical analysis of multiple experimental repeats. Myelinated axons were so abundant that from one litter of embryonic mice, myelin was produced in amounts sufficient for bulk biochemical analysis. This culture method was assessed for its ability to generate an in vitro model of the CNS that could be used for both neurobiological and neuropathological research. Myelin protein kinetics were investigated using a myelin fraction isolated from the cultures. This fraction was found to be superior, quantitatively and qualitatively, to the fraction recovered from standard cultures of dissociated oligodendrocytes, or from brain slices. The model was also used to investigate the roles of specific molecules in the pathogenesis of inflammatory CNS diseases. Using the defined conditions offered by this culture system, dose-specific, inhibitory effects of inflammatory cytokines on myelin formation were demonstrated, unequivocally. The method is technically quick, easy and reliable, and should have wide application to CNS research

Selective neurofilament (SMI-32, FNP-7 and N200) expression in subpopulations of layer V pyramidal neurons in vivo and in vitro

There are two main types of layer V pyramidal neurons in rat cortex. Type I neurons have tufted apical dendrites extending into layer I, produce bursts of action potentials and project to subcortical targets (spinal cord, superior colliculus and pontine nuclei). Type II neurons have apical dendrites, which arborize in layers II-IV, do not produce bursts of action potentials and project to ipsilateral and contralateral cortex. The specific expression of different genes and proteins in these two distinct layer V neurons is unknown. To distinguish between distinct subpopulations, fluorescent microspheres were injected into subcortical targets (labeling type I neurons) or primary somatosensory cortex (labeling type II neurons) of adult rats. After transport, cortical sections were processed for immunohistochemistry using various antibodies. This study demonstrated that antigens recognized by SMI-32, N200 and FNP-7 antibodies were only expressed in subcortical (type I)--but not in contralateral (type II)--projecting neurons. NR1, NR2a/b, PLCbeta1, BDNF, NGF and TrkB antigens were highly expressed in all neuronal subpopulations examined. Organotypic culture experiments demonstrated that the development of neurofilament expression and laminar specificity does not depend on the presence of the subcortical targets. This study suggests specific markers for the subcortical projecting layer V neuron subpopulations

Organotypic Spinal Cord Slice Culture to Study Neural Stem/Progenitor Cell Microenvironment in the Injured Spinal Cord

The molecular microenvironment of the injured spinal cord does not support survival and differentiation of either grafted or endogenous NSCs, restricting the effectiveness of the NSC-based cell replacement strategy. Studying the biology of NSCs in in vivo usually requires a considerable amount of time and cost, and the complexity of the in vivo system makes it difficult to identify individual environmental factors. The present study sought to establish the organotypic spinal cord slice culture that closely mimics the in vivo environment. The cultured spinal cord slices preserved the cytoarchitecture consisting of neurons in the gray matter and interspersed glial cells. The majority of focally applied exogenous NSCs survived up to 4 weeks. Pre-exposure of the cultured slices to a hypoxic chamber markedly reduced the survival of seeded NSCs on the slices. Differentiation into mature neurons was severely limited in this co-culture system. Endogenous neural progenitor cells were marked by BrdU incorporation, and applying an inflammatory cytokine IL-1β significantly increased the extent of endogenous neural progenitors with the oligodendrocytic lineage. The present study shows that the organotypic spinal cord slice culture can be properly utilized to study molecular factors from the post-injury microenvironment affecting NSCs in the injured spinal cord