Inventory Control of Deteriorating Items

The problem of the control and maintenance of inventories of physical goods is common to most enterprises. In the past, inventories were considered as the \u27graveyard\u27 of American business, because surplus stock was a principal cause for business failures. However, in large scale enterprises the inventory system may become too large and complex to be analyzed intuitively and any deviation from the optimum inventory policy would mean substantial losses. As a result of the current small profit margins, proper inventory control has become even more important. The basic concept in inventory control consists of striking a balance between the cost factors which increase as inventories increase and those which decrease as inventories increase. Among the costs which increase are: 1. Interest: (cost of money) Some companies use the interest paid for the capital and others use the return that could have been obtained by investing the capital elsewhere. In either case, the cost of the goods in inventory must be considered. 2. Deterioration costs. Deterioration costs are the losses in value due to actual deterioration, obsolescence or damage of the inventory item. 3. Insurance and taxes. Since most inventories are insured, this cost should be taken into account. Taxes are mainly property taxes. 4. Storage costs. Storage costs include rent, or its equivalent ownership costs, and heat, light and other utility costs. It is the usual practice to combine-all of these costs into a single item called the holding cost or inventory carrying cost, expressed as a percentage of the factory or purchase cost of the items being stored. The decreasing costs are: 1. Ordering cost. The ordering cost is the internal cost incurred in placing and processing a purchase order and is usually assumed to be a constant for each order placed. It would include cost of forms, cost of preparation and, frequently, receiving inspection. 2. Set up costs. The set-up costs are the costs incurred in preparing a machine for the production of an item. It is applicable to items produced internally. This cost is a constant for each set up. 3. Shortage cost. The shortage cost is the cost incurred due to the non-availability of an item in stock. This cost would include the additional cost involved in taking emergency measures to meet the demand in time as well as the loss of customers\u27 good will and positive loss of profit if the demand is not met in time. If a company keeps a spare parts inventory for its own use, the shortage may result in direct losses if a machine becomes inoperative due to the non-availability of spare parts in stock. The shortage cost may depend upon the amount of the. shortage, the duration of the shortage and/or the number of shortages per unit time

SECURITY IN WIRELESS SENSOR NETWORKS USING ASSYMETRIC KEY BASED TECHNIQUES

Wireless sensor networks (WSNs) have recently attracted a lot of interest in the research community due their wide range of applications in our lives ranging from military applications to civilian ones.. Due to distributed nature of these networks and their deployment in remote areas, these networks are vulnerable to numerous security threats that can adversely affect their proper functioning. This problem is more critical if the network is deployed for some mission-critical applications such as in a tactical battlefield. Random failure of nodes is also very likely in real-life deployment scenarios. Due to resource constraints in the sensor nodes, traditional security mechanisms with large overhead of computation and communication are infeasible in WSNs. Security in sensor networks is, therefore, a particularly challenging task. In this current paper, we fundamentally focus on the security issue of WSNs and propose a protocol based on public key cryptography for external agent authentication and session key establishment. The proposed protocol is efficient and secure in compared to other public key based protocols in WSNs

Geographic Market Definition in an International Context

Market definition is generally regarded as a key step in antitrust analysis. Market definition has two components. Product market definition seeks to include all products that are meaningful substitutes. Geographic market definition seeks to incorporate all relevant sources of the product in question. This paper is concerned with geographic market definition and, in particular, how geographic markets are defined in situations where competition may, at least to some extent, transcend national boundaries. The subject of the paper may be of some current interest for two reasons. First, the perception is widespread that, over the past twenty or so years, competition in many products and services has become increasingly international in scope and that this trend will continue. Second, the way in which foreign competition is taken into account in performing the antitrust analysis can have a dramatic impact on the legal or policy conclusions that are reached in a particular instance. The legality of a proposed merger, for example, may turn entirely on how competition from foreign sellers is treated. For antitrust purposes, when we say that competition has become more international in scope, we mean primarily that the range of possible suppliers for many goods and services to U.S. consumers increasingly includes sellers who do not produce or are not primarily headquartered in the United States or that an increasing portion of sales by American-based firms are to customers abroad. Many aspects of antitrust are potentially affected by these changes. Some of the more complex issues involve jurisdictional considerations and these will not be discussed here. As we will see, however, the subject of market definition exposes almost all of the substantive (as opposed to jurisdictional) considerations that come into play when we take account of the international aspect of certain markets. The paper has three main parts. The first focuses on the role market definition plays in antitrust analysis and, in particular, the link between market definition and market power. The second explores the particular issues that are raised with respect to market definition when there is an international aspect to competition. The final section addresses some of the empirical questions raised by the largely theoretical analysis of the first two parts of the paper

Geographic Market Definition in an International Context

Market definition is generally regarded as a key step in antitrust analysis. Market definition has two components. Product market definition seeks to include all products that are meaningful substitutes. Geographic market definition seeks to incorporate all relevant sources of the product in question. This paper is concerned with geographic market definition and, in particular, how geographic markets are defined in situations where competition may, at least to some extent, transcend national boundaries. The subject of the paper may be of some current interest for two reasons. First, the perception is widespread that, over the past twenty or so years, competition in many products and services has become increasingly international in scope and that this trend will continue. Second, the way in which foreign competition is taken into account in performing the antitrust analysis can have a dramatic impact on the legal or policy conclusions that are reached in a particular instance. The legality of a proposed merger, for example, may turn entirely on how competition from foreign sellers is treated. For antitrust purposes, when we say that competition has become more international in scope, we mean primarily that the range of possible suppliers for many goods and services to U.S. consumers increasingly includes sellers who do not produce or are not primarily headquartered in the United States or that an increasing portion of sales by American-based firms are to customers abroad. Many aspects of antitrust are potentially affected by these changes. Some of the more complex issues involve jurisdictional considerations and these will not be discussed here. As we will see, however, the subject of market definition exposes almost all of the substantive (as opposed to jurisdictional) considerations that come into play when we take account of the international aspect of certain markets. The paper has three main parts. The first focuses on the role market definition plays in antitrust analysis and, in particular, the link between market definition and market power. The second explores the particular issues that are raised with respect to market definition when there is an international aspect to competition. The final section addresses some of the empirical questions raised by the largely theoretical analysis of the first two parts of the paper

AZATHIOPRINE INDUCED PANCYTOPENIA-A CASE REPORT

Azathioprine (AZA), a prodrug of 6 mercaptopurine, is an immunosuppressant that can be used as adjunctive therapy with corticosteroids in the treatment of arteritic form of ischemic optic neuropathy. Although myelotoxicity is known to occur while using azathioprine, severe pancytopenia is rarely seen. Patients with thiopurine methyltransferase (TPMT) deficiency are at high risk of developing severe myelosuppression. A 63 year* old female with ischemic optic neuropathy was initiated treatment with oral methylprednisone. As two courses of oral steroids showed no significant improvement, oral azathioprine 25 mg twice daily was added and gradually increased to 50 mg twice daily with relief of symptoms. 6 mo later, she was admitted with acute stroke and lab reports showed low levels of total blood counts or pancytopenia. The patient was put on broad spectrum antibiotics; given injection of granulocyte colony stimulating factor 300 mcg subcutaneously and blood transfusion as correction till counts normalised. She improved over 14 d and on next follow-up counts were in normal range. Causality was assessed by Naranjo causality assessment scale and a probable relationship was obtained between azathioprine and pancytopenia with a score of 6. Variations in TPMT activity occurs due to genetic polymorphism. Physicians should be aware of the possibility of myelosuppression while prescribing azathioprine. Frequent blood count monitoring is the most convenient way to avoid this problem where testing for TPMT deficiency is not possible

Health-related Quality of Life in Vacuum-Assisted Breast Biopsy: short-term effects, long-term effects and predictors

<p>Abstract</p> <p>Background</p> <p>The impact of Vacuum-assisted breast biopsy (VABB, 11-Gauge) upon Health-related Quality of Life (HRQoL) remains an open field. This study aims to: i) assess short-term (4 days after VABB) responses in terms of HRQoL after VABB, ii) evaluate long-term (18 months after VABB) responses, if any, and iii) examine whether these responses are modified by a variety of possible predictors (anthropometric, sociodemographic, lifestyle habits, breast-related parameters, reproductive history, VABB-related features and complications, seasonality).</p> <p>Methods</p> <p>This study included 102 eligible patients undergoing VABB and having benign lesions. A variable number of cores (24-96 cores) has been excised. HRQoL was assessed by EQ-5D and SF-36^®questionnaires: i) in the morning of the VABB procedure day (baseline measurement), ii) four days after VABB (early post-biopsy measurement) and iii) 18 months after VABB (late post-biopsy measurement). Statistical analysis comprised two steps: i. evaluation of differences in EQ-5D/SF-36 dimensions and calculated scores (baseline versus early post-biopsy measurement and baseline versus late post-biopsy measurement) and ii. assessment of predictors through multivariate linear, logistic, ordinal logistic regression, as appropriate.</p> <p>Results</p> <p>At baseline patients presented with considerable anxiety (EQ-5D anxiety/depression dimension, EQ-5D TTO/VAS indices, SF-36 Mental Health dimension). At the early post-biopsy measurement women exhibited deterioration in Usual Activities (EQ-5D) and Role Functioning-Physical dimensions. At the late measurement women exhibited pain (EQ-5D pain/discomfort and SF-36 Bodily Pain), deterioration in Physical Functioning (SF-36 PF) and overall SF-36 Physical Component Scale (PCS). Mastalgia, older age and lower income emerged as significant predictors for baseline anxiety, whereas seasonality modified early activities-related responses. Pain seemed idiosyncratic.</p> <p>Conclusions</p> <p>The HRQoL profile of patients suggests that VABB exerts effects prior to its performance at a psychological level, immediately after its performance at a functioning-physical level and entails long-term effects associated with pain.</p

Wiki or Word? Evaluating Tools for Collaborative Writing and Editing

Businesses and other organizations are relying increasingly on virtual teams to perform a range of business activities. A key challenge in utilizing virtual teams is to support collaboration among team members who are separated by distance and/or time. In this paper we use a research model based on a combination of the Technology Acceptance Model (TAM) and the Task Technology Fit (TTF) model to examine two approaches to supporting students in collaboratively creating and editing a report for an introductory course in information systems. In our study, one group of students used MS Word with Track Changes turned on combined with emailing the document among students. A second group was provided access to a wiki where they created the report. Results show that students found the Word and email combination more useful and easier to use than the wiki environment in completing the project. Further, there was no perceived difference in the effort of collaboration between the two methods. This study raises questions about the widely held belief that web-based collaboration platforms are superior to emailing documents among collaborators