Introduction Inconsistent results from previous studies of exercise and cognitive function suggest that rigorously designed randomized controlled trials are urgently needed. Here, we describe the design of the Intense Physical Activity and Cognition (IPAC) study, which will assess the impact of a 6-month high-intensity exercise intervention on cognitive function and biomarkers of dementia risk,...

Since the mid 1990s, ecologists have intensified their efforts to describe and quantify the effects that biodiversity can exert on the various processes within ecosystems. Both theoretical and experimental work has shown that within a habitat, changing diversity has profound effects on biomass production, nutrient retention, and other ecosystem characteristics such as stability. In most experim...

We study an auction contest for a procurement of innovation. Firms exert effort and the resulting quality of innovation is ex ante uncertain. Given the uncertainty of the quality, there is a trade-off regarding the number of participating firms in the contest: If there are too many firms, they may be discouraged from expanding their investments because each of them has a small chance of winning...

Machining operations of aluminum structural parts are typically carried out under high feeds and high cutting speeds. These cutting conditions exert thermal and mechanical loads on the workpiece, which cause changes in the subsurface material. Residual stresses belong to the machining induced changes and can lead to considerable rejection rates as a consequence of part distortion. Due to the si...

nowadays, organizations are trying to maximize productivity by groups, but the results are not always completely satisfactory thereby causing some problems for organizations such as social loafing. social loafing reduces motivation and effort in team work compared to individual work. this study intends to achieve the necessary mechanisms to reduce social loafing, and reviews the effect of perce...

Background and objective: Improving quality of work- life ‎ of nurses requires existence of an organizational culture with collaborative and compatible features and with purpose and prospect. Human resources in different organizations such as hospitals with different organizational cultures have different interpretations about quality of work- life ‎; therefore, the aim of this study is...

A sample is a group of objects or readings taken from a population for counting or measurement. We shall distinguish between two kinds of populations — finite populations and infinite populations. The sample must be random, meaning that all possible samples of a particular size must have equal probabilities of being chosen from the population. This will prevent bias in the sampling process. Mos...

Let sk = 1 √ N (v1k, . . . , vNk) T , with {vik, i, k = 1, . . .} independent and identically distributed complex random variables. Write Sk = (s1, . . . , sk−1, sk+1, . . . , sK), Pk = diag(p1, . . . , pk−1, pk+1, . . . , pK), Rk = (SkPkS ∗ k + σ 2 I) and Akm = [sk,Rksk, . . . ,R m−1 k sk]. Define βkm = pks ∗ kAkm(A ∗ km ×RkAkm) −1 A ∗ kmsk, referred to as the signalto-interference ratio (SIR)...

BACKGROUND The potential impact of employment on maternal health, particularly in relation to gestational hypertension and pre-eclampsia, has been subject to research. However, there is limited evidence on associations between shift work and long working hours on the incidence of these conditions. AIMS To evaluate potential associations between maternal shift work and long working hours durin...

Gas hydrates, solid composites of biogenically derived gasses (mainly methane) combined with water ice, may be present in marine sediments, especially at continental margins, under the correct pressure and temperature conditions. Gas hydrates are detected by direct sampling, and inferred from seismic reSection data when a strong bottom-simulating reSector (BSR) is produced by the seismic veloci...