A készletgazdálkodás optimalizálási módszereinek gyakorlati alkalmazása

A készletgazdálkodás színvonala a forgóeszköz-gazdálkodáson belül kiemelt szerepű és folyamatosan napirenden lévÅ‘ a vállalatok életében, ami a készletgazdálkodás gazdasági hatásaival magyarázható. A kapcsolódó forrásmunkákban közölt eredmények, a fogalmak értelmezése, az összefüggések gyakorlati alkalmazásának feltételrendszere stb. több ellentmondást is takar, sok esetben hiányos vagy rosszul értelmezett. Jelen tanulmányban a készletgazdálkodással összefüggésben azon ismert módszerek és algoritmusok képezik a kutatás tárgyát, melyeknek elméleti megalapozottsága nem vitatható, de gyakorlati alkalmazásuk több problémát is felvet, melyek az egyes készletgazdálkodási modellek gyakorlati alkalmazásakor, az összefüggésekben szereplÅ‘ változók gazdasági tartalmának értelmezésekor és számszerűsítésekor jelentkeznek. A tanulmány keretében feltárjuk az összefüggésekben szereplÅ‘ változók számszerűsítésének fontosságát, értelmezzük gazdasági tartalmukat, meghatározzuk gyakorlati alkalmazásuk esetén jelentkezÅ‘ problémákat, és javaslatot teszünk a változók számszerűsítésének és gyakorlati alkalmazásuk algoritmusára. ------------------------------------------------ The standard of stock management is always an important issue for the life of any company, chiefly because of the economic effects of stock management. There are numerous controversies in the findings published in the relevant literature, in the interpretation of concepts and in the practical application of the relevant correlations. They are often incomplete or incorrectly interpreted. This paper looks at methods and algorithms relevant to stock management that are unquestionably well-founded theoretically but the practical application of which raises various problems. These problems arise in the course of the practical application of certain stock management models, with respect to the interpretation of the economic meaning and the quantification of variables included in the various functions. The paper explains the importance of quantifying these variables, provides an interpretation of such variables in economic terms, identifies the issues arising in the course of their application in practice, and proposes algorithms for the quantification and practical application of such variables.forgótÅ‘ke, optimális rendelési tételnagyság, készlettartási ráta, készlettartási modellek, working capital, economic order quantity, holding cost (%), stock management models, Farm Management, Financial Economics,

Midair Refueling for Sensation Seeking? Pilot CEOs and Corporate Debt Contracting

We examine the relation between chief executive officer (CEO) sensation seeking, which captures the desire for varied, novel, and complex personal sensations and experiences, and corporate debt contracting. Using pilot certificates as a proxy for the personality trait of sensation seeking, we find that firms with pilot CEOs use longer maturity debt financing even when long-term debt is more costly than short-term debt. Our findings are robust to controlling for the endogenous matching between firms and CEOs. Our evidence indicates that CEOs with sensation-seeking personality traits prefer long-term debt financing to avoid the liquidity risk associated with short-term debt financing that may hamper other corporate activities motivated by their sensation seeking

ON THE NAGELL-LJUNGGREN EQUATION (Analytic Number Theory : Distribution and Approximation of Arithmetic Objects)

We show that there exists an effective upper bound for the solutions to the Nagell-Ljunggren equation of the form --=y^{q} in 4 unknowns in integers x>1, y>1, m>2, q>1, when x is a cube of an integer. Our method relies on a refined estimate of linear forms in logarithms

The ultrastructure and flexibility of thylakoid membranes in leaves and isolated chloroplasts as revealed by small-angle neutron scattering

We studied the periodicity of the multilamellar membrane system of granal chloroplasts in different isolated plant thylakoid membranes, using different suspension media, as well as on different detached leaves and isolated protoplasts—using small-angle neutron scattering. Freshly isolated thylakoid membranes suspended in isotonic or hypertonic media, containing sorbitol supplemented with cations, displayed Bragg peaks typically between 0.019 and 0.023 Å− 1, corresponding to spatially and statistically averaged repeat distance values of about 275–330 Å. Similar data obtained earlier led us in previous work to propose an origin from the periodicity of stroma thylakoid membranes. However, detached leaves, of eleven different species, infiltrated with or soaked in D2O in dim laboratory light or transpired with D2O prior to measurements, exhibited considerably smaller repeat distances, typically between 210 and 230 Å, ruling out a stromal membrane origin. Similar values were obtained on isolated tobacco and spinach protoplasts. When NaCl was used as osmoticum, the Bragg peaks of isolated thylakoid membranes almost coincided with those in the same batch of leaves and the repeat distances were very close to the electron microscopically determined values in the grana. Although neutron scattering and electron microscopy yield somewhat different values, which is not fully understood, we can conclude that small-angle neutron scattering is a suitable technique to study the periodic organization of granal thylakoid membranes in intact leaves under physiological conditions and with a time resolution of minutes or shorter. We also show here, for the first time on leaves, that the periodicity of thylakoid membranes in situ responds dynamically to moderately strong illumination. This article is part of a Special Issue entitled: Photosynthesis research for sustainability: Keys to produce clean energy

Genetic variants in novel pathways influence blood pressure and cardiovascular disease risk.

Blood pressure is a heritable trait influenced by several biological pathways and responsive to environmental stimuli. Over one billion people worldwide have hypertension (≥140 mm Hg systolic blood pressure or  ≥90 mm Hg diastolic blood pressure). Even small increments in blood pressure are associated with an increased risk of cardiovascular events. This genome-wide association study of systolic and diastolic blood pressure, which used a multi-stage design in 200,000 individuals of European descent, identified sixteen novel loci: six of these loci contain genes previously known or suspected to regulate blood pressure (GUCY1A3-GUCY1B3, NPR3-C5orf23, ADM, FURIN-FES, GOSR2, GNAS-EDN3); the other ten provide new clues to blood pressure physiology. A genetic risk score based on 29 genome-wide significant variants was associated with hypertension, left ventricular wall thickness, stroke and coronary artery disease, but not kidney disease or kidney function. We also observed associations with blood pressure in East Asian, South Asian and African ancestry individuals. Our findings provide new insights into the genetics and biology of blood pressure, and suggest potential novel therapeutic pathways for cardiovascular disease prevention

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

Genetic associations at 53 loci highlight cell types and biological pathways relevant for kidney function.

Reduced glomerular filtration rate defines chronic kidney disease and is associated with cardiovascular and all-cause mortality. We conducted a meta-analysis of genome-wide association studies for estimated glomerular filtration rate (eGFR), combining data across 133,413 individuals with replication in up to 42,166 individuals. We identify 24 new and confirm 29 previously identified loci. Of these 53 loci, 19 associate with eGFR among individuals with diabetes. Using bioinformatics, we show that identified genes at eGFR loci are enriched for expression in kidney tissues and in pathways relevant for kidney development and transmembrane transporter activity, kidney structure, and regulation of glucose metabolism. Chromatin state mapping and DNase I hypersensitivity analyses across adult tissues demonstrate preferential mapping of associated variants to regulatory regions in kidney but not extra-renal tissues. These findings suggest that genetic determinants of eGFR are mediated largely through direct effects within the kidney and highlight important cell types and biological pathways