87 research outputs found

    Financial Structure and Market Equilibrium in a Vertically Differentiated Industry

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    This paper examines the effects of uncertainty and the choice of financial structure in a vertically differentiated duopoly. In the market model consumers are located along a continuum of taste parameters and prefer unanimously higher to lower qualities when quality prices are set at average variable cost. In such a model only two firms can survive with a positive market share. We introduce uncertainty in demand by varying the range of the consumer taste parameter and consider a simultaneous game of sequential choices of quality, financial structure and product price, with varying order of decision-making and revelation of information. We consider both restricted and free entry. It is shown that financial structure affects market equilibrium, which is also heavily dependent on the order of choice of structure and quality, as well as on whether uncertainty exists in the lower or the upper limit of the taste parameter. In all cases leverage increases the lower quality and in most cases it also increases the lower quality price. There are also welfare implications, with the use of leverage when it is optimal improving both total and consumer surplus.Vertical differentiation; uncertainty; financial structure; leverage; quality; sequential choice

    Option Pricing and Replication with Transaction Costs and Dividends

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    This paper derives optimal perfect hedging portfolios in the presence of transaction costs within the binomial model of stock returns, for a market maker that establishes bid and ask prices for American call options on stocks paying dividends prior to expiration. It is shown that, while the option holder's optimal exercise policy at the ex-dividend date varies according to the stock price, there are intervals of values for such a price where the optimal policy would depend on the holder's preferences. Nonetheless, the perfect hedging assumption still allows the derivation of optimal hedging portfolios for both long and short positions of a market maker on the option.Pricing; Transaction costs; American options; Dividends

    Исследование особенностей динамики и растворения паромагниевых пузырей, всплывающих в расплаве чугуна

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    Разработана расчетная модель движения и физико-химического взаимодействия газомагниевых пузырей с расплавом чугуна. Проведенные расчеты показали, что в реальных условиях рафинирования чугуна при содержании серы в расплаве вплоть до 0,040%, начальном радиусе пузыря вплоть до 6,5 мм и глубине расплава 2,5 м и более происходит полное усвоение паров магния чугуном

    Comparative palatability of orally disintegrating tablets (ODTs) of praziquantel (L-PZQ and Rac-PZQ) versus current PZQ tablet in African children: a randomized, single-blind, crossover study

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    BACKGROUND: Praziquantel (PZQ) is currently the only recommended drug for infection and disease caused by the schistosome species that infects humans; however, the current tablet formulation is not suitable for pre-school age children mainly due to its bitterness and the large tablet size. We assessed the palatability of two new orally disintegrating tablet (ODT) formulations of PZQ. METHODOLOGY: This randomized, single-blind, crossover, swill-and-spit palatability study (NCT02315352) was carried out at a single school in Tanzania in children aged 6-11 years old, with or without schistosomiasis infection as this was not part of the assessment. Children were stratified according to age group (6-8 years or 9-11 years) and gender, then randomized to receive each formulation in a pre-specified sequence. Over 2 days, the children assessed the palatability of Levo-Praziquantel (L-PZQ) ODT 150 mg and Racemate Praziquantel (Rac-PZQ) ODT 150 mg disintegrated in the mouth without water on the first day, and L-PZQ and Rac-PZQ dispersed in water and the currently available PZQ 600 mg formulation (PZQ-Cesol) crushed and dispersed in water on the second day. The palatability of each formulation was rated using a 100 mm visual analogue scale (VAS) incorporating a 5-point hedonic scale, immediately after spitting out the test product (VASt = 0 primary outcome) and after 2-5 minutes (VASt = 2-5). PRINCIPAL FINDINGS: In total, 48 children took part in the assessment. Overall, there was no reported difference in the VASt = 0 between the two ODT formulations (p = 0.106) without water. Higher VASt = 0 and VASt = 2-5 scores were reported for L-PZQ ODT compared with Rac-PZQ ODT in older children (p = 0.046 and p = 0.026, respectively). The VASt = 0 and VASt = 2-5 were higher for both ODT formulations compared with the standard formulation (p<0.001 for both time points). No serious adverse events were reported. CONCLUSIONS/SIGNIFICANCE: The new paediatric-friendly formulations dispersed in water were both found to be more palatable than the existing standard formulation of PZQ. There may be gender and age effects on the assessment of palatability. Further research is needed for assessing efficacy and tolerability of the newly ODTs Praziquantel drug in younger children. TRIAL REGISTRATION: The trial was registered on ClinicalTrials.gov (NCT02315352) and in the Pan African Clinical Trials Registry (PACTR201412000959159)

    Novel Insights Regarding the Operational Characteristics and Teleological Purpose of the Renal Na+-K+-Cl2 Cotransporter (NKCC2s) Splice Variants

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    The absorptive Na+-K+-Cl− cotransporter (NKCC2) is a polytopic protein that forms homooligomeric complexes in the apical membrane of the thick ascending loop of Henle (TAL). It occurs in at least four splice variants (called B, A, F, and AF) that are identical to one another except for a short region in the membrane-associated domain. Although each of these variants exhibits unique functional properties and distributions along the TAL, their teleological purpose and structural organization remain poorly defined. In the current work, we provide additional insight in these regards by showing in mouse that the administration of either furosemide or an H2O-rich diet, which are predicted to alter NKCC2 expression in the TAL, exerts differential effects on mRNA levels for the variants, increasing those of A (furosemide) but decreasing those of F and AF (furosemide or H2O). Based on a yeast two-hybrid mapping analysis, we also show that the formation of homooligomeric complexes is mediated by two self-interacting domains in the COOH terminus (residues 671 to 816 and 910 to 1098), and that these complexes could probably include more than one type of variant. Taken together, the data reported here suggest that A, F, and AF each play unique roles that are adapted to specific physiological needs, and that the accomplishment of such roles is coordinated through the splicing machinery as well as complex NKCC2–NKCC2 interactions

    Caractérisation moléculaire de CCC8 (aussi appelé SLC12A9), un transporteur de polyamines putatif localisé sur la membrane apicale du tubule proximal

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    Les cotransporteurs cation-Cl (CCCs) appartiennent à une grande famille de protéines qui comprend neuf isoformes : CCCl à CCC7, qui permettent le mouvement du Cl" avec celui d'un Na+ et/ou K+ à travers la membrane cellulaire, CCC9, qui agit comme un transporteur de polyamine (PA) - glutamate, et CCC8, dont on en connaît pas la fonction. Les CCCs font aussi partie d'une famille plus large de protéines qui sont regroupées sous le nom de « amino acid - polyamine - orgcmocation carriers (APC) ». À l'exception de CCC9, cependant, les protéines impliquées dans le transport des PAs n'ont été isolées que chez les unicellulaires et ne font pas nécessairement partie de la famille des APC. Dans cette étude, nous avons trouvé que CCC8 joue vraisemblablement le rôle de transporteur de polyamines chez des espèces plus complexes puisque son expression dans les cellules HEK-293 augmente l'influx de spermidine à la surface cellulaire et puisque cette protéine est ubiquitaire chez les mammifères. Nous avons aussi observé que l'influx de spermidine dirigé par les cellules exprimant CCC8 est inhibé par la pentamidine, le methyl-glyoxal-bis-guanylhydrazone, le furosémide et la paraquat, et que cet influx est aussi associé avec celui certains ions comme le Na+ et le Cl". Ainsi, un groupe de substrats qui sont transportés par CCC8 a été découvert pour la première fois suite à ce travail tout comme l'identification d'un nouveau système de transport de polyamines dans les cellules animales. Ces résultats ont un intérêt majeur puisque les polyamines intracellulaires jouent un rôle clé dans la prolifération cellulaire

    Phloeodictines: nouvelles substances antibiotiques de type pyrrolo [1,2-a] pyrimidine isolees de l'eponge neo-caledonienne Phloeodictyon sp

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    SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 82884 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc
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