5,236 research outputs found

    Determination the different categories of buyers based on the Jaynes’ information principle

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    Purpose: The article aims to reduce the volume of statistical data, necessary for determination the buyer’s structure. The correct clustering of clients is important for successful activity for both commercial and non-profit organizations. This issue is devoted to a large number of studies. Their main mathematical apparatus is statistical methods. Input data are results of buyer polls. Polls are labor-consuming and quite often annoying buyers. The problem of determination of structure (various categories) of buyers by the mathematical methods demanding a small amount of these polls is relevant. Design/Methodology/Approach: The approach offered in this report based on the Jaynes' information principle (principle of maximum entropy). Jaynes idea is as follows. Let us consider a system in which the conditions cannot be calculated or measured by an experiment. However, each state of the system has a certain measured implication, the average value of which is known (or can be defined), and the average result of these implications is known from the statistical data. Then the most objective are probabilities of states maximizing Shannon’s entropy under restrictions imposed by information about average implications of states. Findings: In this work the task of determination of percentage of buyers for computer shop by the average check is set and solved provided that average checks for each concrete category of buyers are known. Input data for calculation are their average checks. Determination of these values requires much less statistical data, than to directly determine relative number of buyers of various categories. Practical Implications: The results are of particular interest to marketing experts. Originality/Value: The article deals with practical situation when initially there are only three different groups of customers. For this case, the problem of maximizing entropy under given constraints reduced to the problem of finding a solution to a system of three equations, of which only one is nonlinear. This is a completely new result.peer-reviewe

    Minimizing the maximum risk of currency conversion for a company buying abroad

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    Purpose: The relevance of the study is due to the fact that the task of determining the moment of transition from one currency to another arises for each organization, which is not limited to work in the domestic market. This article is aimed at solving the problem of performing the operation of required sale (exchange) of the available currency to pay for goods to a foreign supplier. Design/Methodology/Approach: There are two days to complete the exchange, which must be completed in no more than two steps. In the literature, the leading approach to solving this problem is the prediction of the exchange rate. Findings: The solution proposed in this article is based on Savage's criteria (regret metric). We minimize the maximum risk of unprofitable exchange. This allows you to prevent large deviations from the minimum possible amount of sale of the available currency necessary to purchase a given amount in another currency. Practical Implications: The article presents the prerequisites for the emergence of the task of determining the moment of transition from one currency to another, reveals the specifics of this task in Russian companies, identifies the main tools for solving problems of this type, justifies the use of the proposed approach to solve this problem. Originality/Value: Article submissions are of practical value for managers of companies trading with constant foreign partners, especially under the condition that the operations of converting a significant sum fulfil often, but not daily.peer-reviewe

    Diagnostics of projects

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    The importance of the problem under investigation is to find an effective way to manage the defaults occurred in case of a project which has not enough control during the process of implementation. Usually it goes to delays, and as a consequence to it in very poor quality. The purpose of the article is to provide the project with the necessary level of control by placing control points in it. The article suggests methods for determining the places and necessity for conducting inspections during the construction period of the project. The materials of the article can be used by project managers for more efficient and qualitative management, for faster completion with the lowest possible cost in the highest possible quality.peer-reviewe

    From Small-Scale Dynamo to Isotropic MHD Turbulence

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    We consider the problem of incompressible, forced, nonhelical, homogeneous, isotropic MHD turbulence with no mean magnetic field. This problem is essentially different from the case with externally imposed uniform mean field. There is no scale-by-scale equipartition between magnetic and kinetic energies as would be the case for the Alfven-wave turbulence. The isotropic MHD turbulence is the end state of the turbulent dynamo which generates folded fields with small-scale direction reversals. We propose that the statistics seen in numerical simulations of isotropic MHD turbulence could be explained as a superposition of these folded fields and Alfven-like waves that propagate along the folds.Comment: kluwer latex, 7 pages, 7 figures; Proceedings of the International Workshop "Magnetic Fields and Star Formation: Theory vs. Observations", Madrid, 21-25 April 2003 -- published version (but the e-print is free of numerous typos introduced by the publisher

    Cardiovascular Diseases That Have Emerged From the Darkness

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    It is important for both the patient and physician communities to have timely access to information recognizing rapid progress in the diagnosis and treatment of familiar but relatively uncommon cardiovascular diseases. Patients with 3 cardiovascular diseases (ie, hypertrophic cardiomyopathy, pulmonary arterial hypertension, and transthyretin (TTR) cardiac amyloidosis (ATTR)]), once considered rare without effective management options and associated with malignant prognosis, have now benefited substantially from the development of a variety of innovative therapeutic strategies. In addition, in each case, enhanced diagnostic testing has expanded the patient population and allowed for more widespread administration of contemporary treatments. In hypertrophic cardiomyopathy, introduction of implantable defibrillators to prevent sudden death as well as high-benefit:low-risk septal reduction therapies to reverse heart failure have substantially reduced morbidity and disease-related mortality (to 0.5% per year). For pulmonary arterial hypertension, a disease once characterized by a particularly grim prognosis, prospective randomized drug trials with aggressive single (or combined) pharmacotherapy have measurably improved survival and quality of life for many patients. In cardiac amyloidosis, development of disease-specific drugs can for the first time reduce morbidity and mortality, prominently with breakthrough ATTR-protein-stabilizing tafamidis. In conclusion, in less common and visible cardiovascular diseases, it is crucial to recognize substantial progress and achievement, given that penetration of such information into clinical practice and the patient community can be inconsistent. Diseases such as hypertrophic cardiomyopathy, pulmonary arterial hypertension, and ATTR cardiac amyloidosis, once linked to a uniformly adverse prognosis, are now associated with the opportunity for patients to experience satisfactory quality of life and extended longevity

    Prevalence of suspected hypertrophic cardiomyopathy or left ventricular hypertrophy based on race and gender in teenagers using screening echocardiography

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    BACKGROUND:The goal of this study was to evaluate the prevalence of suspected hypertrophic cardiomyopathy (HCM) in a population of teenagers undergoing screening echocardiography for the detection of HCM.METHOD:The Anthony Bates Foundation performs screening echocardiography for the prevention of sudden death. A total of 2,066 students were studied between the ages of 13 to 19 years. Suspected HCM was defined as any wall thickness greater than or equal to] 15 mm. LVH was defined as wall thickness greater than or equal to] 13 mmRESULTS:Prevalence of suspected HCM was 0.7% (14/2066). After adjusting for hypertension (HTN), the total prevalence was 0.5% (8/1457). In a subgroup analysis, 551 teenagers with documented race and LV wall thickness were identified between the ages of 13 - 19 years. African American teenagers 6% (3/50)] had higher prevalence of suspected HCM 0.8% (4/501), OR 7.93, CI 1.72-36.49, p = 0.002]. After multivariate adjustment for age, gender, BMI and HTN (systolic BP >140 and diastolic BP of > 90), African American race remained independently associated with suspected HCM (OR 4.89, CI 1.24-39.62, p = 0.02).CONCLUSION:The prevalence of suspected HCM in young teenagers is approximately 0.2%. This prevalence appears to be higher in African Americans. However, due to small number of African Americans in our population, our result needs to be confirmed in larger trials.This item is part of the UA Faculty Publications collection. For more information this item or other items in the UA Campus Repository, contact the University of Arizona Libraries at [email protected]

    Feline Hypertrophic Cardiomyopathy: A Spontaneous Large Animal Model of Human HCM.

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    Hypertrophic cardiomyopathy (HCM) is a common disease in pet cats, affecting 10-15% of the pet cat population. The similarity to human HCM, the rapid progression of disease, and the defined and readily determined endpoints of feline HCM make it an excellent natural model that is genotypically and phenotypically similar to human HCM. The Maine Coon and Ragdoll cats are particularly valuable models of HCM because of myosin binding protein-C mutations and even higher disease incidence compared to the overall feline population. The cat overcomes many of the limitations of rodent HCM models, and can provide enhanced translation of information from in vitro and induced small animal models to human clinical trials. Physicians and veterinarians working together in a collaborative and interdisciplinary approach can accelerate the discovery of more effective treatments for this and other cardiovascular diseases affecting human and veterinary patients
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