نتایج جستجو برای: copper worker
تعداد نتایج: 103384 فیلتر نتایج به سال:
There have been much speculation and debate concerning the effect of electromagnetic fields (EMF) on body systems. Various reports have implicated excessive exposure to EMF to certain forms of leukemia. It has also been reported that EMF may cause alteration in the levels of certain macro- and micro-nutrients such as copper, zinc, selenium, calcium and iron. We have undertaken this study to det...
In "Altruism and the Origin of the Worker Caste," Bert Hölldobler and Edward Osborne Wilson explore the evolutionary origins of worker ants. "Altruism and the Origin of the Worker Caste" is the fourth chapter of Hölldobler and Wilson's book, The Ants, which was published by The Belknap Press of Harvard University [4] in Cambridge, Massachusetts, in 1990. In "Altruism and the Origin of the Worke...
healthy hire effect (hhe) is considered as an epidemiological phenomenon, complicating the assessment of a true cause - effect relationship between occupational exposure and health status of workers. the current study was aimed at identification and elimination of hhe in the risk assessment of arterial hypertension (ah) in coal miners. overall, 1553 miners, working in west siberia, were enrolle...
An important and fundamental step in breeding honeybees is the separation of honeybee populations in Iran. During the years 1992-1996, several research works were directed towards the investigation of genetic populations of the Iranian honeybee (Apis mellifera L.), using biochemical methods. For this purpose, samples of worker bees were taken from 251 colonies of 115 apiaries in 84 cities in 21...
Worker policing, wherein social insect workers prevent their sisters from reproducing by eating worker-laid eggs, is recognized as a textbook example of kin selection in action. However, the evolutionary basis of policing was recently challenged in a study that suggested that police-workers remove worker-laid eggs not because rearing workers' sons reduces worker fitness, but merely because work...
Objectives: Mental health organizations are strongly encouraged to implement empirically supported treatments (ESTs), however little is known about their working environments. The present study investigated how provider demographics, workplace environment and whether ESTs were used affected the worker morale. Methods: Front-line workers (N = 1,273) from 55 different programs in a single, large ...
Social evolution in honey bees has produced strong queen-worker dimorphism for plastic traits that depend on larval nutrition. The honey bee developmental programme includes both larval components that determine plastic growth responses to larval nutrition and nurse components that regulate larval nutrition. We studied how these two components contribute to variation in worker and queen body si...
Work flow policies are shown to induce a change in average between-workers variability (worker heterogeneity) and within-worker variability in performance times. In a laboratory experiment, the authors measured the levels of worker heterogeneity and within-worker variability under an individual performance condition, a work sharing condition, and a fixed assignment condition. The work sharing p...
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