Recent trends in modeling of deteriorating inventory

4. Modelling Survival Data in Medical Research

This paper presents a complete and up-to-date survey of published inventory literature for the deteriorating (decaying) inventory models. More specifically, those papers are addressed that consider the effect of deterioration as a function of the on-hand level of inventory. The basic features, extensions and generalization of various models are discussed. A classification scheme is presented along with suggestions for future research.

https://link.springer.com/content/pdf/10.1057%2Fjors.1991.4.pdf

Survey of Literature on Continuously Deteriorating Inventory Models

Infertility and problems of impaired fecundity have been a concern through ages and is also a significant clinical problem today, which affects 8-12% of couples worldwide. Of all infertility cases, approximately 40-50% is due to "male factor" infertility and as many as 2% of all men will exhibit suboptimal sperm parameters. It may be one or a combination of low sperm concentration, poor sperm motility, or abnormal morphology. The rates of infertility in less industrialized nations are markedly higher and infectious diseases are responsible for a greater proportion of infertility. The present literature will help in knowing the trends of male factor infertility in developing nations like India and to find out in future, various factors that may be responsible for male infertility.

Trends of male factor infertility, an important cause of infertility: A review of literature.

Approximately 10 to 15% of couples are impacted by infertility. Recently, the pivotal role that lifestyle factors play in the development of infertility has generated a considerable amount of interest. Lifestyle factors are the modifiable habits and ways of life that can greatly influence overall health and well-being, including fertility. Many lifestyle factors such as the age at which to start a family, nutrition, weight, exercise, psychological stress, environmental and occupational exposures, and others can have substantial effects on fertility; lifestyle factors such as cigarette smoking, illicit drug use, and alcohol and caffeine consumption can negatively influence fertility while others such as preventative care may be beneficial. The present literature review encompasses multiple lifestyle factors and places infertility in context for the couple by focusing on both males and females; it aims to identify the roles that lifestyle factors play in determining reproductive status. The growing interest and amount of research in this field have made it evident that lifestyle factors have a significant impact on fertility.

/pdf/lifestyle-factors-and-reproductive-health-taking-control-of-ob45s39pgz.pdf

Lifestyle factors and reproductive health: taking control of your fertility

OBJECTIVE The study was designed to assess the hepatitis B virus (HBV) and hepatitis C virus (HCV) co-infection scenario among the human immunodeficiency virus (HIV) infected patients attending a tertiary healthcare unit in eastern India. Additionally, clinical and virological characterization of these viruses, prior to antiretroviral therapy (ART) initiation was also done for better understanding of the disease profile. METHODS Pool of ART-naive HIV/HBV co-infected and HIV mono-infected patients, participating in two different studies, were included in this study. HBV DNA was detected by nested-PCR amplification followed by HBV genotype determination and HBV reverse transcriptase (RT) region amplification and direct sequencing for detecting drug resistance. RESULTS The prevalence of HBsAg (11.3%) was higher compared to anti-HCV (1.9%) among the HIV infected ART-naive patients. Moreover, majority of the HBeAg positive HIV/HBV co-infected patients (87.7%) had HBV DNA ≥20,000 IU/ml with median HBV DNA significantly higher than that of HBeAg negative subjects (5.7 log10 IU/ml vs. 4.2 log10 IU/ml; p<0.0001). Multivariate analysis also showed that HBeAg-positive status was independently associated with higher HBV DNA level (p = <0.001). Notably, 60.9% of the HBeAg negative co-infected subjects had HBV DNA ≥2,000 IU/ml of which 37.0% had HBV DNA ≥20,000 IU/ml. Genotype HBV/D (68.2%) was the predominant genotype followed by HBV/A (24.3%) and HBV/C (7.5%). Anti-HBV drug resistant mutations were detected in two (3.8%) of the ART-naive patients. CONCLUSION The prevalence of HIV/HBV co-infection was relatively higher in our study subjects. HBeAg testing might provide clue for early treatment initiation. Furthermore, HBeAg negative patients are also associated with high HBV DNA levels and therefore require appropriate medical attention. Pre-treatment screening for anti-HBV drug resistant mutations is not necessary before ART initiation.

/pdf/characterization-of-treatment-naive-hiv-hbv-co-infected-18n26dxtqv.pdf

Characterization of Treatment-Naive HIV/HBV Co-Infected Patients Attending ART Clinic of a Tertiary Healthcare Centre in Eastern India

This paper considers an inventory model for items with a constant rate of decay, when lead time is random having an exponential distribution. The policy is to place an order with a supply centre whenever a demand is made or an item in stock deteriorates. The optimal stock to be maintained is obtained by minimising the total expected cost per unit time.

The (S-1, S) Inventory Model for Deteriorating Items with Exponential Lead Time

In this article, we obtain the UMVUE of the reliability function ξ=P(Y>X) and the UMVUE of ξ k =[P(Y>X)] k in the two-parameter exponential distributions with known scale parameters. We also derive the distribution of the UMVUE of ξ and further considering the tests of hypotheses regarding the reliability function ξ.

Estimation and testing of P(Y > X) in two-parameter exponential distributions

Minimax designs for optimum mixtures

In this paper we study a periodic review inventory model with stock dependent demand. When stock on hand is zero, the inventory manager offers a price discount to customers who are willing to backorder their demand. Permissible delay in payments allowed to the inventory manager is also taken into account. Numerical examples are cited to illustrate the model. Keywords : Periodic review model; stock dependent demand; shortage; price discount on backorder; delay in payment. MSC: 90B05. Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */
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/pdf/a-periodic-review-inventory-model-with-stock-dependent-gr1jefyde0.pdf

Manisha Pal

Papers

Characterization of Treatment-Naive HIV/HBV Co-Infected Patients Attending ART Clinic of a Tertiary Healthcare Centre in Eastern India

The (S-1, S) Inventory Model for Deteriorating Items with Exponential Lead Time

Estimation and testing of P(Y > X) in two-parameter exponential distributions

Minimax designs for optimum mixtures

A periodic review inventory model with stock dependent demand, permissible delay in payment and price discount on backorders