Search results for "MECHANICS"
showing 10 items of 9361 documents
The Principles of Quantum Theory
2013
This chapter develops the formal framework of quantum mechanics: the mathematical tools, generalization and abstraction of the notion of state, representation theory, and a first version of the postulates on which quantum theory rests.
Effects of different backpack loads in acceleration transmission during recreational distance walking
2013
It is well established nowadays the benefits that physical activity can have on the health of individuals. Walking is considered a fundamental method of movement and using a backpack is a common and economical manner of carrying load weight. Nevertheless, the shock wave produced by the impact forces when carrying a backpack can have detrimental effects on health status. Therefore, the aim of this study was to investigate differences in the accelerations placed on males and females whilst carrying different loads when walking. Twenty nine sports science students (16 males and 13 females) participated in the study under 3 different conditions: no weight, 10% and 20% body weight (BW) added in …
Treadmill and Running Speed Effects on Acceleration Impacts: Curved Non-Motorized Treadmill vs. Conventional Motorized Treadmill
2021
An increase in the popularity of running can be seen over the last decades, with a large number of injuries on it. Most of the running injuries are related to impact accelerations and are due to overuse. In order to reduce the risk of injury or to improve performance and health new treadmill designs have been created, as it can be the curved non-motorized treadmill. The aim of this study was to analyse impact accelerations, spatio-temporal parameters and perceptual differences while running on curved non-motorized treadmill (cNMT) compared to motorized treadmill (MT) at different speeds. Therefore, 27 recreational runners completed two tests consisting of 10 min warm-up and three bouts of 8…
P776 Stress ecocardiography and speckle tracking analysis in patients with heart failure and preserved ejection fraction
2020
Abstract BACKGROUND Heart failure with preserved ejection fraction (HFpEF) is characterized by heart failure symptoms despite preserved LV systolic function together with at least one among left ventricle hypertrophy/left atrial enlargement plus diastolic dysfunction (DD) and increased brain natriuretic peptide levels. Rest echocardiography could still be normal despite patients experience HF symptoms. Speckle tracking analysis (STE) analyzes myocardial deformation and is able to identify subtle left ventricular dysfunction. PURPOSE to analyze the added value of stress echocardiography to improve diagnostic accuracy in patients with normal ejection fraction and unexplained dyspnoea by evalu…
MAIN ROUTES OF TRANSMISSION OF HUMAN IMMUNODEFICIENCY VIRUS (HIV) INFECTION IN A FAMILY SETTING IN PALERMO, ITALY1
1988
A cross-sectional seroepidemiologic study was carried out on household contacts and sexual partners of human immunodeficiency virus (HIV) antibody-positive intravenous drug abusers in Palermo, Italy, in 1985 to evaluate factors that influenced HIV transmission. A total of 43 index cases, 36 spouses or heterosexual partners, 28 children, and 55 adult household members were enrolled. None of the household members without sexual contact, who had shared items and facilities and had interacted with the index cases, contracted HIV infection. However, six of 36 sexual partners had antibodies to HIV. It was observed that the risk of HIV infection was significantly associated with the frequency of s…
Is the El Niño-Southern Oscillation likely to increase the risk of Fasciola transmission?
2007
(2007). Is the El Nino–Southern Oscillation likely to increase the risk of Fasciola transmission? Annals of Tropical Medicine & Parasitology: Vol. 101, No. 6, pp. 555-557.
Molecular Surveillance of HIV-1 in Madrid, Spain: a Phylogeographic Analysis ▿
2011
ABSTRACT The molecular epidemiology of HIV-1 is constantly changing, mainly as a result of human migratory flows and the high adaptive ability of the virus. In recent years, Spain has become one of Europe's main destinations for immigrants and one of the western European countries with the highest rates of HIV-positive patients. Using a phylogeographic approach, we have analyzed the relationship between HIV-1 variants detected in immigrant and native populations of the urban area of Madrid. Our project was based on two coincidental facts. First, resistance tests were extended to naïve and newly diagnosed patients, and second, the Spanish government legislated the provision of legal status t…
A biomechanical evaluation of methods of distal humerus fracture fixation using locking compression plates versus conventional reconstruction plates.
2004
OBJECTIVES To examine the biomechanical behavior of 2 techniques of double-plate osteosynthesis for fractures of the adult distal humerus using conventional reconstruction plates and locking compression plates. DESIGN Basic science study. SETTING Experimental in vitro study. PATIENTS/PARTICIPANTS Forty fresh-frozen human distal humeri specimens. INTERVENTION Four matched groups with 10 humeri each, median age 74 years (46-95), were created using similar bone mineral density values. Two standard configurations of double-plate osteosynthesis (dorsal or 90 degrees configuration) with either conventional reconstruction plates or locking compression plates were studied for biomechanical properti…
Trunk kinematics during cross country sit-skiing ergometry: Skiing strategies associated to neuromusculoskeletal impairment
2016
Since trunk function plays a major role in propulsion in sit-skiers and athletes belonging to distinct classes have different abilities to control trunk muscles, the aim of this study is to evaluate how athletes personalized their skiing strategy to compensate their impairment and improve skiing effectiveness. Sixteen Paralympic sit-skiers belonging to different classes volunteered as participant. Each athlete executed two double poling tests on a ski ergometer at the maximal speed he/she can reach and the best, identified as the fastest, was considered in the analysis. A set of two passive reflective markers was used for kinematic analysis: the first marker was placed on the athlete should…
Similar biomechanical properties of four tripled tendon graft models for ACL reconstruction
2021
Abstract Purpose The present study tested and compared the biomechanical properties of four different triplicate graft tendon techniques. Methods 32 tripled tendons from the common extensor muscle of bovine fingers were tested on a material testing machine, passing the end loop over a metal rod of a clevis connected to the load cell on the upper side, and fixing the lower end to a clamp. The samples were divided into four groups: (A) tripled with a free end sutured only to one of the two fixed bundles (B) tripled with a free end positioned between the two fixed strands and sutured to both (C) tripled with an S-shape and all the three strands sutured together at the upper and lower extremiti…