Acute Effects of Exercise on Cognitive Performances of Older Adults

Accelerating rates of structural decline become evident during the third and fourth decades of human life, with disproportionate degeneration occurring in the frontal, parietal, and temporal brain lobes. As the structure of the brain declines, a broad array of cognitive processes involving memory, decision making, and selective attention are reduced as well (Raz 2000, Park et al. 2001). Cardiovascular exercise has been associated with improved cognitive functioning in aging humans, suggesting that increased vascular supply enhances availability of oxygen, nutrients, and other physical entities to nourish the brain. Previous experimentation on older adults revealed significant positive effects of exercise on a variety of memory types following participation in a program six or more months in duration (Colcombe 2003, Kramer et al.1999). The primary focus of this study was to test the effects of acute aerobic exercise on cognitive functioning of adults over the age of 60. A second purpose was to determine that the positive neurological effects of exercise can start taking place immediately. The hypothesis is that memory retention, mental processing speed, and selective attention would acutely improve in the participants after they had exercised, in comparison to their cognitive state prior to exercise. Cognitive performances both before and after exercise were tested using the Stroop test. All participants completed the post-exercise test with improved scores (p=0.000) indicating an increase in cognitive ability, relating exercise and improved cognitive function

Finite volume effects in a quenched lattice-QCD quark propagator

We investigate finite volume effects in the pattern of chiral symmetry breaking. To this end we employ a formulation of the Schwinger-Dyson equations on a torus which reproduces results from the corresponding lattice simulations of staggered quarks and from the overlap action. Studying the volume dependence of the quark propagator we find quantitative differences with the infinite volume result at small momenta and small quark masses. We estimate the minimal box length L below which chiral perturbation theory cannot be applied to be L \simeq 1.6 fm. In the infinite volume limit we find a chiral condensate of ||_{\bar{MS}}^{2 GeV} = (253 \pm 5.0 MeV)^3, an up/down quark mass of m_{\bar{MS}}^{2 GeV} = 4.1 \pm 0.3 MeV and a pion decay constant which is only ten percent smaller than the experimental value.Comment: 19 pages, 8 figures. v2: minor clarifications added, version published in PR

Response of Fishes to Revetment Placement

Routine fish sampling with hoop nets was conducted monthly from April through December 1978 along natural and revetted riverbanks on the lower Mississippi River near Eudora, Arkansas, to monitor changes in fish populations affected by placement of new revetment for bank protection. Eighteen species of fish were collected with four species comprising over 75% of the total catch. During the months prior to revetment placement, freshwater drum, Aplodinotus grunniens, was the most abundant (32.7% of the catch) species collected. Following in abundance were the flathead catfish, Pylodictis olivaris, (9.8%), common carp, Cyprinus carpio, (7.8%), and blue catfish, Ictalurus furcatus, (3.3%). After revetment placement in August 1978, the freshwater drum was again the most abundant component, comprising 9.7% of the catch. Gizzard shad, Dorosoma cepedianum, flathead catfish, and blue catfish followed in abundance and comprised 8.9, 4.1, and 3.4% of the total catch, respectively. Catch per effort data indicated that fish were generally more abundant at natural bank stations than revetted bank stations but the difference was not significant. The study suggests that fish inhabiting natural riverbank habitat recover quite rapidly from bank perturbation caused by the placement of revetment

Quark Condensates: Flavour Dependence

We determine the q-bar q condensate for quark masses from zero up to that of the strange quark within a phenomenologically successful modelling of continuum QCD by solving the quark Schwinger-Dyson equation. The existence of multiple solutions to this equation is the key to an accurate and reliable extraction of this condensate using the operator product expansion. We explain why alternative definitions fail to give the physical condensate.Comment: 9 pages, 7 figures, uses appolb.cls, LaTeX. Talk presented by R. Williams at the EURIDICE Final Meeting, August 24-27th, 2006, Kazimierz, Polan

In a Gondola : Barcarolle

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