Asymptotic approximations to the nodes and weights of Gauss-Hermite and Gauss-Laguerre quadratures

Asymptotic approximations to the zeros of Hermite and Laguerre polynomials are given, together with methods for obtaining the coefficients in the expansions. These approximations can be used as a standalone method of computation of Gaussian quadratures for high enough degrees, with Gaussian weights computed from asymptotic approximations for the orthogonal polynomials. We provide numerical evidence showing that for degrees greater than $100$ the asymptotic methods are enough for a double precision accuracy computation ($15$-$16$ digits) of the nodes and weights of the Gauss--Hermite and Gauss--Laguerre quadratures.Comment: Submitted to Studies in Applied Mathematic

Computation of the Marcum Q-function

Methods and an algorithm for computing the generalized Marcum $Q-$function ($Q_{\mu}(x,y)$) and the complementary function ($P_{\mu}(x,y)$) are described. These functions appear in problems of different technical and scientific areas such as, for example, radar detection and communications, statistics and probability theory, where they are called the non-central chi-square or the non central gamma cumulative distribution functions. The algorithm for computing the Marcum functions combines different methods of evaluation in different regions: series expansions, integral representations, asymptotic expansions, and use of three-term homogeneous recurrence relations. A relative accuracy close to $10^{-12}$ can be obtained in the parameter region $(x,y,\mu) \in [0,\,A]\times [0,\,A]\times [1,\,A]$, $A=200$, while for larger parameters the accuracy decreases (close to $10^{-11}$ for $A=1000$ and close to $5\times 10^{-11}$ for $A=10000$).Comment: Accepted for publication in ACM Trans. Math. Soft

A Political Economy of the Immigrant Assimilation: Internal Dynamics

Within immigrant society different groups wish to help the migrants in different ways – immigrant societies are multi-layered and multi-dimensional. We examine the situation where there exists a foundation that has resources and that wishes to help the migrants. To do so they need migrant groups to invest effort in helping their country-folk. Migrant groups compete against one another by helping their country-folk and to win grants from the foundation. We develop a model that considers how such a competition affects the resources invested by the groups’ supporters and how beneficial it is to immigrants. We consider two alternative rewards systems for supporters – absolute and relative ranking – in achieving their goals.

Migration and Culture

Culture is not new to the study of migration. It has lurked beneath the surface for some time, occasionally protruding openly into the discussion, usually under some pseudonym. The authors bring culture into the open. They are concerned with how culture manifests itself in the migration process for three groups of actors: the migrants, those remaining in the sending areas, and people already living in the recipient locations. The topics vary widely. What unites the authors is an understanding that though actors behave differently, within a group there are economically important shared beliefs (customs, values, attitudes, etc.), which we commonly refer to as culture. Culture and identify play a central role in our understanding of migration as an economic phenomenon; but what about them matters? Properly, we should be looking at the determinants of identity and the determinants of culture (prices and incomes, broadly defined). But this is not what is done. Usually identity and culture appear in economics articles as a black box. Here we try to begin to break open the black box.migration, culture

High bioaccumulation of cadmium and other metals in Patagonian edible gastropods

High concentrations of metals are accumulated by edible marine resources, affecting human health. Marine gastropods have been commercially captured and consumed in Argentina for decades without official regulations or studies to guarantee their safety. In this study, metals (cadmium, aluminium, iron, zinc, copper and lead) were analysed for the first time in the edible marine gastropods Buccinanops globulosus, Adelomelon ancilla and Trophon geversianus and their surrounding sediments. Taking into account the maximum levels recommended by national and international regulations for food safety, we recommend consuming only the foot of these gastropod species. We recommend not consuming these gastropods from harbour areas due to concentrations of lead in sediments and tissues. Though the target hazard quotient (THQ) of cadmium was not high for the local community, it could be higher for other populations who consume molluscs more frequently, indicating a potential health risk of chronic exposure. Monitoring of these and other contaminants should be performed in order to ensure food safety of these marine resources.Fil: Primost, Monica Angelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; ArgentinaFil: Gil, Mónica N.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; ArgentinaFil: Bigatti, Gregorio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina. Universidad Nacional de la Patagonia; Argentin

Migration and Culture

Culture is not new to the study of migration. It has lurked beneath the surface for some time, occasionally protruding openly into the discussion, usually under some pseudonym. The authors bring culture into the open. They are concerned with how culture manifests itself in the migration process for three groups of actors: the migrants, those remaining in the sending areas, and people already living in the recipient locations. The topics vary widely. What unites the authors is an understanding that though actors behave differently, within a group there are economically important shared beliefs (customs, values, attitudes, etc.), which we commonly refer to as culture. Culture and identify play a central role in our understanding of migration as an economic phenomenon; but what about them matters? Properly, we should be looking at the determinants of identity and the determinants of culture (prices and incomes, broadly defined). But this is not what is done. Usually identity and culture appear in economics articles as a black box. Here we try to begin to break open the black box.

Why Pay Taxes When No One Else Does?

In this paper we try to understand the phenomena whereby a large proportion of the population evades tax payments. We present a model which incorporates elements from the theory of information cascades with the standard model of tax evasion and analyze the connection between the decision of a potential tax evader, the number of tax evaders and the number caught in previous periods. General conditions exist under which any expected utility maximizing tax evaders will decide to emulate other tax evaders.uncertainty, information cascades, tax evasion

A Political Economy of the Immigrant Assimilation: Internal Dynamics

Within immigrant society different groups wish to help the migrants in different ways – immigrant societies are multi-layered and multi-dimensional. We examine the situation where there exists a foundation that has resources and that wishes to help the migrants. To do so they need migrant groups to invest effort in helping their country-folk. Migrant groups compete against one another by helping their country-folk and to win grants from the foundation. We develop a model that considers how such a competition affects the resources invested by the groups’ supporters and how beneficial it is to immigrants. We consider two alternative rewards systems for supporters – absolute and relative ranking – in achieving their goals.migration, assimilation, political economy