The principle of operant selection is examined as a prototype of cultural selection, and the role of the social environment is suggested as the critical element in the emergence of cultural phenomena. Operant contingencies are compared to cultural selection contingencies, designated as metacontingencies. Both of these types of contingency relations result in evolving lineages of recurrences tha...

To deal with nonpoint sources of pollution, such as stream sediment produced by erosion from forest management operations, regulations require land managers to reduce onsite erosion to keep the amount of sediment discharged from each project area within acceptable limits. Activities developed to meet these regulations are sometimes referred to as best management practices (BMPs). BMPs are desig...

PURPOSE To examine the effects of genetic polymorphisms in cytochrome P450, subfamily 1, polypeptide 1 (C1P1B1) on primary open-angle glaucoma (POAG). METHODS A systematic literature search was performed, and random-effects meta-analyses were used to evaluate genetic polymorphisms in CYP1B1 with POAG. A gene-based analysis was conducted to investigate the cumulative effects of genetic polymor...

The purpose of this study was to examine the impact of cumulative risk exposure in concert with maternal responsiveness on physiological indicators of chronic stress in children and youth. Middle-school children exposed to greater accumulated psychosocial (e.g., family turmoil, poverty) and physical (e.g., crowding, substandard housing) risk factors manifested higher levels of allostatic load, ...

Aalen’s additive hazards model has gained increasing attention in recently years because it model all covariate effects as time-varying. In this thesis, our goal is to explore the application of Aalen’s model in assessing treatment effect at a given time point with varying covariate effects. First, based on Aalen’s model, we utilize the direct adjustment method to obtain the adjusted survival o...

BACKGROUND The objectives of this study were to determine whether cross-shift changes in peak expiratory flow rate (PEFR) were related to respirable dust exposure in South African coalminers. METHODS Fifty workers were randomly selected from a cohort of 684 miners from 3 bituminous coalmines in Mpumalanga, South Africa. Peak expiratory efforts were measured prior to the commencement of the sh...

the aim of this study was investigating the effect of gamma irradiation and naoh treatment of some agricultural by products (tomato pulp, orange pulp, pistachio hull and wheat straw) on fermentation parameters and gas production test. treatments of gamma irradiation (50, 100 and 200 kgy) and %5 naoh was done on each source of by products. the results showed that gamma irradiation at the dose of...

background and purpose: leukemia is the most prevalent type of cancer in children and its prognostic factors vary in different geographic locations. the aim of this study was to estimate the 5 years survival rate of children suffering from leukemia in kerman, iran and to investigate the factors which might influence it. materials and methods: this was a cohort study conducted on patients with a...

The preservation of QoS for multimedia traffic through a data network is a difficult problem. We focus our attention on video frame rate and study its influence on speech perception. When sound and picture are discrepant (e.g., acoustic “ba” combined with visual “ga”), subjects perceive a different sound (such as “da”). This phenomenon is known as the McGurk effect. In this paper, the influence...

Objective(s) In the present study, the differences in the relaxant effects of aqueous, ethyl acetate and n-butanol fractions of Rosa damascena on tracheal smooth muscle of guinea pigs were examined. Materials and Methods The relaxant effects of three cumulative concentrations of each fraction (0.1, 0.2 and 0.4 g%) in comparison with saline and three cumulative concentrations of theophylline ...