Imperfect quality items are unavoidable in an inventory system due to imperfect production process, natural disasters, damages, or many other reasons. The setup cost and production cycle time can be related in terms of process deterioration and learning and forgetting effects. Learning reduces production run length and setup cost, whereas deterioration and forgetting increases both. Keeping the...

Asexual species accumulate deleterious mutations through an irreversible process known as Muller's ratchet. Attempts to quantify the rate of the ratchet have ignored the role of temporal environmental heterogeneity even though it is common in nature and has the potential to affect overall ratchet rate. Here we examine Muller's ratchet in the context of conditional neutrality (i.e., mutations th...

Leli and Filskov (1979) reported cross-validated classification accuracy that equalled 83% for a discriminant function derived on two measures of intellectual deterioration. This investigation made a preliminary assessment of the clinical utility of this function through a clinical-actuarial classification paradigm. Wechsler-Bellevue Intelligence Scale Form I protocols from 12 nonpsychotic noni...

HEALTH ISSUE: Total fertility rates (TFRs) have decreased worldwide. The Canadian fertility rate has gone from 3.90 per woman in 1960 to 1.49 in 2000. However, not many studies have examined the impact on women's health of reduced fertility rates, delayed fertility and more births to unmarried women. This paper presents information on the relation between family size and specific determinants o...

Ageing in many organisms, including humans, is accompanied by marked alterations in both general and specific protein synthesis. Protein synthesis is normally under tight control by a broad array of regulatory factors, which facilitate appropriate rates of mRNA translation. Are the wide changes in protein synthesis simply a corollary of the ageing process or do they have a causative role in sen...

this paper presents an inventory model for deteriorating items in which shortages are allowed. it is assumed that the production rate is proportional to the demand rate and greater than demand rate. the inventory model is developed by considering four different circumstances. the optimal of the problem is obtained with the help of mathematica 7 software. numerical examples are given to illustra...

This paper deals with an integrated model for the joint determination of economic production quantity and preventive maintenance (PM) level for an imperfect process having a general deterioration distribution with increasing hazard rate. The effect of PM activities on the deterioration pattern of the process is modeled using the imperfect maintenance concept. It is assumed that, after each PM, ...

This paper reviews various impacts of urbanization on rivers and streams, which lead to symptoms summarized by the general term “urban stream syndrome”. Growing areas of impervious surfaces cause deterioration of water recipients flowing through urban areas. The symptoms of deterioration usually include altered chemical parameters of water and sediment, accumulation of priority pollutants in aq...

Objective: Recent studies have begun to look at the impact of the economic crisis on mental health. This paper tries to summarize the most important findings with regard to effects of the economic crisis on mental health in Spain on the basis of a comprehensive literature review. Results: Most of the studies agree on the negative consequences on mental health of the Spanish economic crisis. A d...