On Population Structure and Marriage Dynamics

I develop an equilibrium, two-sided search model of marriage with endogenous population growth to study the interaction between fertility, the age structure of the population and the age at first marriage of men and women. Within a simple two-period overlapping generation model I show that, given an increase of the desired number of children, age at marriage is affected through two different channels. First, as population growth increases, the age structure of the population produces a thicker market for young people, inducing early marriages. The second channel comes from differential fecundity: if the desired number of children is not feasible for older women, women tend to marry younger and men older, with single men outnumbering single women in equilibrium. Using an extended version of the model to a finite number of periods and fertility data, I show that two mechanisms described above may have acted as persistence mechanisms after the U.S “baby boom”. I show that demographic transitional dynamics after the baby boom may account for approximately a 23% of the increase in men's age of marriage between 1985 and 2009, albeit the impact on women's age is small.population structure, marriage, search

Gender differences and the timing of first marriages

In this article we provide a simple model of the marriage market where singles search for spouses. In our model economy men and women live for many years and they differ in their survival probabilities, in their fecundity, and in their earnings. We show that modelling the marriage decision in a very simple model economy is sufficient to account for much of the observed marriage behavior in the United States in the year 2000. We conclude that gender differences in fecundity are all important in accounting for marriage behavior, and that differences in earnings matter little. We also conclude that, even though they are in short supply, the market power of fecund women is not enough for them to demand compensation in all cases. And that studying the marriage decision without modelling explicitly the roles played by age and by fecundity, as has been typically done by the previous literature, makes little sense

Building envelope design as a contribution for improvement of urban spaces and social housing environmental quality

The design of building envelope and the definition of its elements, can influence both the quality of the external spaces perception and the living standard referred to internal building spaces. This improvement depends by the planning of some component design. Particularly, solar shadings and integrated plant solutions, also thanks to an increasing consequential interest about the issue and the legislative and normative evolution, represent factors able to be involved both in the performance and morphological quality of building envelope (improvement of energy efficiency and living quality of internal spaces), which can influence the perception of environment. A study about this questions has been conducted through the elaboration of a system of Best Pratices, a Code of Practice, for the new Plans of Zone of Rome Municipality. The indications contained in the Code takes in examination the integration-mitigation and facilities connection of solar collectors in the building design, and the possibility of integration between solar shading and collector elements, customized like a support tool for the sustainable design of building envelope. The design of building envelope, reported to morphological and technological issues, can assume particular importance in the definition of living quality. Design of closures, developed through some indications referred to its technological components, can influence both the quality perception of external living spaces through the morphological definition of building, and the life quality of internal spaces by the implementation of energy efficiency of building system. Solar shading in particular, also thanks to the increasing consequential interest in the evolution of legislation about the argument, more in the future will represent a fundamental element for design and the increment of performance and morphological quality of building enclosure

Gender Differences and the Timing of First Marriages

We study the steady state of an overlapping generations economy where singles search for spouses. In our model economy men and women live for many years and they differ in their fecundity, in their earnings, and in their survival probabilities. These three features are age-dependent and deterministic. Singles meet at random. They propose when the expected value of their current match exceeds that of remaining single. If both partners propose, the meeting ends up in a marriage. Marriages last until death does them apart, widows and widowers never remarry, and people make no other economic decisions whatsoever. In our model economy people marry because they value companionship, bearing children, and sharing their income with their spouses. The matching function depends on the single sex-ratios which are endogenous. Our model economy has only two free parameters: the search friction and the utility share of bearing children. We choose their values to match the median ages of first-time brides and grooms. We show that modeling the marriage decision in this simple way is sufficient to account for the age distributions of ever and never married men and women, for the probabilities of marrying a younger bride and a younger groom, and for the age distributions of first births observed in the United States in the year 2000. The previous literature on this topic claims that marriage is a waiting game in which women are choosier than men, and old and rich pretenders outbid the young and poor ones in their competition for fecund women. In this article we tell a different story. We show that their shorter biological clocks make women uniformly less choosy than men of the same age. This turns marriage into a rushing game in which women are willing to marry older men because delaying marriage is too costly for women. Our theory predicts that most of the gender age difference at first marriage will persist even if the gender wage-gap disappears. It also predicts that the advances in the reproductive technologies will play a large role in reducing the age difference at first marriage.marriage, search, sex ratio

The Impact of Unilateral Divorce on Crime

In this paper, we evaluate the impact of unilateral divorce on crime. First, using crime rates from the FBI’s Uniform Crime Report program for the period 1965-1998 and differences in the timing in the introduction of the reform, we find that unilateral divorce has a positive impact on violent crime rates, with an 8% to 12% average increase for the period under consideration. Second, arrest data not only confirms the findings of a positive impact on violent crime but also shows that this impact is concentrated among those age groups (15 to 24) that are more likely to engage in these type of offenses. Specifically, for the age group 15-19, we observe an average impact over the period under analysis of 40% and 36% for murder and aggravated assault arrest rates, respectively. Disaggregating total arrest rates by race, we find that the effects are driven by the Black sub-sample. Third, using the age at the time of the divorce law reform as a second source of variation to analyze age-specific arrest rates we confirm the positive impact on the different types of violent crime as well as a positive impact for property crime rates, controlling for all confounding factors that may operate at the state-year, state age or age-year level. The results for murder arrests and for homicide rates (Supplemental Homicide Report) for the 15-24 age groups are robust with respect to specifications and specifically those that include year-state and year-age dummies. The magnitude goes from 15% to 40% depending on the specification and the age at the time of the reform.arrest rates, unilateral divorce, crime rates

Gender differences and the timing of first marriages

In this article we provide a simple model of the marriage market where singles search for spouses. In our model economy men and women live for many years and they differ in their survival probabilities, in their fecundity, and in their earnings. We show that modelling the marriage decision in a very simple model economy is sufficient to account for much of the observed marriage behavior in the United States in the year 2000. We conclude that gender differences in fecundity are all important in accounting for marriage behavior, and that differences in earnings matter little. We also conclude that, even though they are in short supply, the market power of fecund women is not enough for them to demand compensation in all cases. And that studying the marriage decision without modelling explicitly the roles played by age and by fecundity, as has been typically done by the previous literature, makes little sense.Marriage, Search, Sex ratio

First record of Curius chemsaki Nearns and Ray, 2006 (Coleoptera: Cerambycidae: Cerambycinae: Curiini) in Colombia

Curius chemsaki Nearns and Ray, 2006 (Coleoptera: Cerambycidae: Cerambycinae: Curiini), is reported from Colombia for the first time. In addition, the range of this taxon within Venezuela is extended to the Andean Province of Táchira

Fractal structure of hadrons and non-extensive statistics

The role played by non-extensive thermodynamics in physical systems has been under intense debate for the last decades. Some possible mechanisms that could give rise to non-extensive statistics have been formulated along the last few years, in particular the existence of a fractal structure in thermodynamic functions for hadronic systems. We investigate the properties of such fractal thermodynamical systems, in particular the fractal scale invariance is discussed in terms of the Callan-Symanzik~equation. Finally, we propose a diagrammatic method for calculations of relevant quantities.Comment: 5 pages, 2 figures. Presented by E.Megias at the QCD@Work: International Workshop on QCD, 25-28 June 2018, Matera, Ital