985 research outputs found
Regulation of ovulation number in mammals. A follicle interaction law that controls maturation
No full textThe assumption that developing follicles communicate through circulating hormones has been used to obtain a class of interaction laws that describe follicle growth. A specific member of this class has been shown to control ovulation number. Although all interacting follicles obey the same growth law and are given initial maturities that are chosen at random from a uniform distribution, ovulatory and atretic follicles emerge. Changing the parameters in the growth law can alter the most probable ovulation number values, anovulatory states are also admitted as possible solutions of the growth law. The behavior of the model is examined for interacting follicle populations of different size. Methods are suggested for identifying growth laws in particular mammals. These can be used to test the model from experimental data
The Fed's entry into check clearing reconsidered
No full textCheck collection systems ; Federal Reserve System
Currency quality and changes in the behavior of depository institutions
No full textBanks and banking
A gastric acid secretion model
No full textA theory of gastric acid production and self-protection is formulated mathematically and examined for clinical and experimental correlations, implications, and predictions using analytic and numerical techniques. In our model, gastric acid secretion in the stomach, as represented by an archetypal gastron, consists of two chambers, circulatory and luminal, connected by two different regions of ion exchange. The capillary circulation of the gastric mucosa is arranged in arterial-venous arcades which pass from the gastric glands up to the surface epithelial lining of the lumen; therefore the upstream region of the capillary chamber communicates with oxyntic cells, while the downstream region communicates with epithelial cells. Both cell types abut the gastric lumen. Ion currents across the upstream region are calculated from a steady-state oxyntic cell model with active ion transport, while the downstream ion fluxes are (facilitated) diffusion driven or secondarily active. Water transport is considered iso-osmotic. The steady-state model is solved in closed form for low gastric lumen pH. A wide variety of previously performed static and dynamic experiments on ion and CO2 transport in the gastric lumen and gastric blood supply are for the first time correlated with each other for an (at least) semiquantitative test of current concepts of gastric acid secretion and for the purpose of model verification. Agreement with the data is reported with a few outstanding and instructive exceptions. Model predictions and implications are also discussed
Revision of Lacquer Range
No full textDetta examensarbete utfördes på lack- och tryckavdelningen på företaget Emballator Ulricehamns Bleck med målet att undersöka om det fanns brister och slöserier i det befintliga lacksortimentet. Efter en noggrann nulägesanalys som inkluderade bland annat genomgång av applicerbara datablad, arbetsplatsintroduktion och studiebesök hos en av företagets lackleverantörer genomfördes arbetet utan missöden. Nulägesanalysen resulterade i en översikt av dagens lacksortiment och efter det fortsatte arbetet med att ta fram en egenskapsmatris innehållande samtliga lacker i sortimentet. Efter att de lacker som föll inom författarens specifikation för dubbletter identifierats togs ett antal rekommendationer för hur företaget bör agera för att ha ett uppdaterat sortiment fram. Förutom detta har författaren tagit fram ett förslag på hur företaget skall testa sina insideslacker för att i framtiden ha möjligheten att undersöka om några av dessa kan tas ut ur sortimentet.This degree project was performed in the coating and printing department at Emballator Ulricehamns Bleck. The task was to investigate if any waste and improvement opportunities in the lacquer range at Emballator Ulricehamns Bleck exist. A thorough analysis of the current situation including a review of applicable data, work place introduction and a visit to one of the company´s suppliers was made. This gave a good understanding of the current status. The result of the analysis was an overview of the lacquer range that helped the author to compile a characteristic matrix including all the products in the lacquer range. Following this the author identified products that could be specified as duplicates. Furthermore the degree project has resulted in 5 recommendations regarding future work with the design of the lacquer range. The last part of the project resulted in an analysis of today’s test schedule and a suggestion how to modify it for future needs
Sharp uniform-in-time propagation of chaos
No full textWe prove the optimal rate of quantitative propagation of chaos, uniformly in
time, for interacting diffusions. Our main examples are interactions governed
by convex potentials and models on the torus with small interactions. We show
that the distance between the -particle marginal of the -particle system
and its limiting product measure is , uniformly in time, with
distance measured either by relative entropy, squared quadratic Wasserstein
metric, or squared total variation. Our proof is based on an analysis of
relative entropy through the BBGKY hierarchy, adapting prior work of the first
author to the time-uniform case by means of log-Sobolev inequalities.Comment: 28 page
Competition and regulation in European retail payment systems
No full textIn this study, the interaction between the competition-cooperation nexus and regulation in retail payment systems is analysed by applying the main lessons from the theory of network industries. This is justifiable on the grounds that the payment systems industry inherently has many characteristics in common with network industries. On the other hand, since the provision of payment services also has many special characteristics, the regulatory tools commonly used in many other network industries cannot be applied directly. In general, the main role of payment system regulators is to provide a level playing field for different service providers. To secure dynamic efficiency, the regulators also need to ensure adequate incentives for innovation and investment. In this respect, it is important that they do not take too restrictive an attitude towards cooperation among payment service providers. In addition to general policy analysis, the study also analyses developments in the European retail payment system field and the roles and aims of market participants.competition policy; payment systems; retail payments; network economics
Competition and regulation in European retail payment systems
No full textIn this study, the interaction between the competition-cooperation nexus and regulation in retail payment systems is analysed by applying the main lessons from the theory of network industries. This is justifiable on the grounds that the payment systems industry inherently has many characteristics in common with network industries. On the other hand, since the provision of payment services also has many special characteristics, the regulatory tools commonly used in many other network industries cannot be applied directly. In general, the main role of payment system regulators is to provide a level playing field for different service providers. To secure dynamic efficiency, the regulators also need to ensure adequate incentives for innovation and investment. In this respect, it is important that they do not take too restrictive an attitude towards cooperation among payment service providers. In addition to general policy analysis, the study also analyses developments in the European retail payment system field and the roles and aims of market participants.Competition policy, payment systems, retail payments, network economics
Understanding intraday credit in large-value payment systems
No full textThis article explains how large-value payment systems work, using either gross or net settlement. The author discusses risk control in a real-time gross settlement system and analyzes the pricing of credit to provide intraday liquidity. She argues for distinguishing between consumption/investment debt and payment debt. A theoretical model suggests that, under the assumption that there are no opportunities for intraday optimization of consumption and production, the risk-free rate on intraday payment credit should be zero. This is because the cost of intraday liquidity is a transaction cost of the underlying goods/assets trade and, thus, should be minimized.Payment systems ; Credit ; Debt ; Liquidity (Economics)
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