Vascular function, physical performance and aging

This is a series of three experiments with brachial artery flow-mediated dilation (BAFMD) as the major outcome variable. The first study examined the temporal response of the brachial artery diameter following forearm occlusion in sixteen young (28±8 years) and fifteen older (85±8 years) men. Following release of the pressure cuff there is a significant reduction in brachial diameter compared to baseline, followed by a rapid increase to a PEAK. When comparing the magnitude of the decrease in diameter and the BAFMD between Young and Old, older subjects demonstrated a blunted response. A significant relation was noted between the magnitude of decrease and BAFMD (r=- 0.44, p= 0.04). Specific features of the biphasic pattern are blunted in older adults compared with younger subjects. The magnitude of the drop in diameter following forearm occlusion correlates with the magnitude of the BAFMD. The second study examined the relation between BAFMD and the total score from the Continuous Scale Physical Function Performance Test (PFP-10). Sixty-four men (84±11years) were studied. BAFMD was associated with the total PFP-10 score (r = 0.45, p = 0.0001) and age (r = -0.36, p = 0.003). When individuals were categorized based on their PFP-10 score, those in the highest functional class, exhibited the highest BAFMD, compared to those in the middle class, who had greater vasoreactivity than those in the lowest functional class. The final study examined the effects of four weeks of unilateral handgrip exercise training on BAFMD and the features of the vasoreactivity curve. Twelve men (81±5 years) were studied before, during and after four weeks of handgrip training of the non-dominant arm. Following training, a 40% increase in BAFMD was observed in the trained arm only. Significant improvements in BAFMD were observed after the second week of training (p=0.024). Also, BAFMD was significantly related to the estimated shear rate (r=0.341, p\u3c0.001). A biphasic pattern was not observed in the present study. A significant improvement in BAFMD was observed following unilateral handgrip training. These improvements take place very rapidly and may be partly mediated through increases in shear stress resulting from changes in resistance vessel function

Assessing Physical Activity During a High Altitude Trek in Peru

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Greater Forearm Blood Flow is Associated With Higher Physical Activity in Older Individuals

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Effects of Altitude on Step Test Performance

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The Association Between Body Composition and Acute Mountain Sickness

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Greater Energy Cost During Standardized Walking is Associated With Diminished Fitness in Older Adults

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Zastosowanie sztucznych sieci neuronowych do rozpoznawania obrazów

The paper contains information on artificial neural network. Is shown how the inputs, weights, summary block, block theactivation and output, which consists of an artificial neuron. In part of the research was presented on how the network is built with a Adalineneurons recognize patterns letters graphics.Praca zawiera informacje dotyczące sztucznej sieci neuronowej. Przedstawiony jest sposób działania wejść, wag, bloku sumarycznego, bloku aktywacji i wyjść, z których składa się sztuczny neuron. Omówiona jest struktura sieci z jakiego rodzaju funkcji aktywacji i ilości warstw się składa oraz metody procesu uczenia sieci neuronowej. Zaprezentowany model neuronu typu Adaline. Praca zwiera także informacje dotyczące obrazu cyfrowego, z czego się składa oraz modeli barw na drodze algebraicznej. W części badawczej zostało zaprezentowane w jaki sposób sieć zbudowana z neuronów typu Adaline rozpoznaje wzorce pisma grafiki rastrowej. Omówiony jestsposób przygotowania materiałów testujących oraz tworzenie zbioru uczącego i struktury sieci w zaprojektowanym programie.Przedstawiony jest proces uczenia sieci, jak również rodzaje przykładowych odpowiedzi jakich udziela sieć podczas testowania. Częśćbadawcza zawiera eksperyment w którym ukazane są ważne czynniki jakie wpływają na poprawne działanie sieci

The Relation Between Self-Reported Activity and Fitness Levels in Primary Care

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Assessing the Prevalence of Sleep Apnea among Collegiate Football Players

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Influence of venous emptying on the reactive hyperemic blood flow response

BACKGROUND: Previous research indicates that venous emptying serves as a stimulus for vasodilation in the human forearm. This suggests the importance of recognizing the potential influence of venous volume on reactive hyperemic blood flow (RHBF) following occlusion. The purpose of this study was to examine the influence of venous emptying on forearm vascular function. METHODS: Forearm RHBF, venous capacitance and venous outflow were examined in 35 individuals (age = 22 ± 2 years), using mercury in-Silastic strain gauge plethysmography, at rest and following five minutes of upper arm occlusion using standard procedures (Control). In addition, the same measures were obtained following five minutes of upper arm occlusion preceded by two minutes of passive arm elevation (Pre-elevation). RESULTS: Average resting arterial inflow was 2.42 ± 1.11 ml·100 ml(-1)·min(-1). RHBF and venous capacitance were significantly greater during Pre-elevation compared to Control (RHBF; Pre-elevation: 23.76 ± 5.95 ml·100 ml(-1 )·min(-1 )vs. Control: 19.33 ± 4.50; p = 0.001), (venous capacitance; Pre-elevation: 2.74 ± 0.89 % vs. Control: 2.19 ± 0.97, p = 0.001). Venous outflow did not differ between the two conditions. CONCLUSION: Venous emptying prior to upper arm occlusion results in a significant greater RHBF response and venous capacitance. Recognition of the influence of venous volume on RHBF is particularly important in studies focusing on arterial inflow, and also provides further evidence for the interplay between the venous and arterial system