Energy-Entropy-Momentum integration of discrete thermo-visco-elastic dynamics.

A novel time integration scheme is presented for the numerical solution of the dynamics of discrete systems consisting of point masses and thermo-visco-elastic springs. Even considering fully coupled constitutive laws for the elements, the obtained solutions strictly preserve the two laws of thermo dynamics and the symmetries of the continuum evolution equations. Moreover, the unconditional control over the energy and the entropy growth have the effect of stabilizing the numerical solution, allowing the use of larger time steps than those suitable for comparable implicit algorithms. Proofs for these claims are provided in the article as well as numerical examples that illustrate the performance of the method

A characterization of some families of Cohen--Macaulay, Gorenstein and/or Buchsbaum rings

We provide algorithmic methods to check the Cohen--Macaulayness, Buchsbaumness and/or Gorensteiness of some families of semigroup rings that are constructed from the dilation of bounded convex polyhedrons of $\R^3_{\geq}$. Some families of semigroup rings are given satifying these properties

Public sector wage gaps in Spanish regions.

This paper provides an approximation to the measurement of public sector wage gaps in Spanish regions. By using data from the European Community Household Panel, it is shown that the balance between what private firms pay in the local market and what the public sector pays, differs substantially in different areas of the country. Public sector wage differences among Spanish regions are mostly due to differences in returns, not to differences in characteristics or to selection effects, and are not constant across gender, educational levels, or occupations. Moreover, in those regions where Regional Governments have a higher weight in public employment, public wage gaps are higher and public employers pay higher returns. There also seems to be a cross-regional positive correlation between public wage gaps and unemployment, and a negative one between labour productivity and public wage gaps. Hence, a tentative conclusion is that the incentives to select into the public sector are higher in the low productivity regions, precisely those where scarcity of human capital in the private sector may be the most important factor for explaining economic backwardness.public sector, wage differentials, switching regressions, Spanish regions.

Tourism as an economic development tool. Key factors

Tourism may serve as tool of economic development (ED). The aim of this article is to determine, through the analysis of determining factors identified in previous studies, which are the most important variables in channeling tourism growth into ED. Using a multivariate linear regression model, the main push and brake factors have been identified, for both developed and developing countries. It has been concluded that countries should maintain low initial provisions for CO2 emissions, hospital beds, unemployment, energy without CO2 emissions, and working population. It is also necessary to reduce conflict-related deaths. These results may be crucial in the decision-making processes implemented by policymakers and destination managers, given that they provide extremely useful information for the planning of their actions

On pseudo-Frobenius elements of submonoids of Nd

Producción CientíficaIn this paper we study those submonoids of Nd with a nontrivial pseudo-Frobenius set. In the affine case, we prove that they are the affine semigroups whose associated algebra over a field has maximal projective dimension possible. We prove that these semigroups are a natural generalization of numerical semigroups and, consequently, most of their invariants can be generalized. In the last section we introduce a new family of submonoids of Nd and using its pseudo-Frobenius elements we prove that the elements in the family are direct limits of affine semigroups.Ministerio de Economía, Industria y Competitividad (project MTM2017-84890-P)Ministerio de Economía, Industria y Competitividad - Fondo Europeo de Desarrollo Regional (project MTM2015-65764-C3-1-P

Analyzing the Bidirectional Relationship between Tourism Growth and Economic Development

After having demonstrated the relationship between tourism and economic growth, tourism-led economic growth (TLGH), and economic-driven tourism growth (EDTG), the scientific literature was concerned with studying the relationship between tourism and economic development, limiting itself to analyzing a possible unidirectional relationship between tourism, economic growth, and economic development. In this context, the aim of this article is to determine if the relationship between tourism and economic development is bidirectional given that, although tourism can be a tool for economic development, it is also true that a higher level of economic development influences tourism growth. Using a sample of 143 countries, and applying confirmatory factor analysis together with a structural equations model, the bidirectional relationship is confirmed. Therefore, although tourism growth and economic development face different challenges, if public policies work in a coordinated manner, they may contribute significantly to improving economic development in countries that are configured as tourist destinations

Generalized Strongly Increasing Semigroups

In this work, we present a new class of numerical semigroups called GSI-semigroups. We see the relations between them and other families of semigroups and we explicitly give their set of gaps. Moreover, an algorithm to obtain all the GSI-semigroups up to a given Frobenius number is provided and the realization of positive integers as Frobenius numbers of GSI-semigroups is studied.The first-named author was partially supported by the Spanish Projects MTM2016-80659-P and PID2019-105896GB-I00. The second and third-named authors were partially supported by the Spanish Project MTM2017-84890-P and Junta de Andalucia groups FQM-343 and FQM-366

Is there a common pattern of dental specialties in the world? Orthodontics, the constant element

Background There is a lack of studies comparing the status of dental specialties worldwide. Therefore, this study aimed to analyze the differences and similarities between the number and types of dental specialties in 31 countries, including every continent, in the world. Materials and methods Available official documents and webpages from regulatory bodies, official colleges and councils, and dental institutions were collected from 31 countries and analyzed to obtain reliable data on dental specialties. Differences were analyzed using the Lorentz curve and Gini test. Additionally, a cluster analysis was performed to obtain groups of countries with similar patterns in the number and types of dental specialties. Results A total of 32 different specialties were officially recognized among all the analyzed countries. Orthodontics and oral surgery (100% and 93.1%, respectively) were the two most frequently officially recognized dental specialties worldwide. The total global degree of inequality in the 31 analyzed countries was 42.4%. The Anglo-Saxon countries showed the greatest similarity, approximately 15-fold higher than the European countries. Cluster analysis differentiated six main groups of countries according to the number and types of dental specialties. European countries formed one of the two largest clusters, and the other cluster was of Anglo-Saxon, Asian, African, and several Eastern European countries with a high number of specialties. Conclusions Officially recognized dental specialties in the different continents and countries show an asymmetric organization. The number, names, and skills of officially recognized dental specialties exhibited significant differences, showing inequalities in their organization. The Anglo-Saxon pattern of dental specialties showed greater equality than the European pattern. Orthodontics was the only constant element among the different patterns

Thermodinamically consistent dynamic formulation of discrete thermoviscoelastic elements

Metodología para integrar numéricamente de forma termodinámicamente consistente las ecuaciones del problema termomecánico acoplado de un elemento discreto viscoso