author reports a case of 67- years- old men referred to donga university hospital silicosis who had worked in tunnel drilling where presumably had been exposed to high concentration free silica for almost 20 yr. this report is considered the first in korea to the best of our knowledge since no cases on silicosis could be reported in this occupation in reviewing various literature sources in kor...

Using behavioral experiments, we examined the impact of dispensability of effort and salience of feedback on worker productivity and how they can be managed via queueing design. We considered two queue design features: queue structure that can either be parallel queues (multiple queues with a dedicated server per queue) or a single queue (a single pooled queue served by multiple providers); and...

Purpose: the transformation of marriage patterns and family formation by following transition from traditional society to a modern society causes changes in goals, function of family formation. The aim of this study was comparative investigation of the attitudes of single and married individuals about marriage function. Materials and method: the study performed by qualitative method. The statis...

The theory of inclusive fitness provides a powerful explanation for reproductive altruism in social insects, whereby workers gain inclusive fitness benefit by rearing the brood of related queens. Some ant species, however, have unicolonial population structures where multiple nests, each containing numerous queens, are interconnected and individuals move freely between nests. In such cases, nes...

A major source of oppression in industrial and post-industrial society is the restrictive and highly authoritarian nature of the workplace. One response is to democratize the workplace by increasing the participation of workers in making decisions and in choosing and evaluating managers as well as sharing in the ownership of the firm. These are not new ideas, and there are many examples of orga...

The dynamics and throughput of a bucket brigade production system is studied when workers speeds increase due to learning. It is shown that, if the rules of the bucket brigade system allow a re-ordering of its workers then the bucket brigade production system is very robust and will typically rebalance to a self-organizing optimal production arrangement. As workers learn only those parts of the...

use of the double ring infiltrometer to measure soil water infiltration in center pivot irrigation systems isn’t an accurate approach because the real conditions of infiltration under center pivot sprinklers is different from what happens in the double ring. in this study the infiltration parameters were evaluated in real conditions of a center pivot system. for this purpose a single ring with ...