Divorce Chinese Style

This study investigated divorce during China's social and economic transformation period from 1970 to 2012. Specifically, the study examined the trend development of divorce and demonstrated how marriage formation type and individual socioeconomic characteristics were associated with the likelihood of divorce across time. Event‐history analysis was applied to longitudinal data from the China Family Panel Studies (2010–2012 waves). The results showed a threefold increase in divorce from the pre‐1990s to the 1990s. Surprisingly, the trend shifted to a plateau toward the 2000s. When cohabitation was in its rapidly diffusing stage in the 1990s, individuals who cohabited prior to marriage had a substantially higher likelihood of divorce. As cohabitation became increasingly common in the 2000s, its effect on divorce weakened. The role of socioeconomic characteristics in divorce also varied across time. This study enriches the knowledge of family dynamics in contemporary Chinese society.     

Improved Approximation for Breakpoint Graph Decomposition and Sorting by Reversals

Sorting by Reversals (SBR) is one of the most widely studied models of genome rearrangements in computational molecular biology. At present, is the best known approximation ratio achievable in polynomial time for SBR. A very closely related problem, called Breakpoint Graph Decomposition (BGD), calls for a largest collection of edge disjoint cycles in a suitably-defined graph. It has been shown that for almost all instances SBR is equivalent to BGD, in the sense that any solution of the latter corresponds to a solution of the former having the same value. In this paper, we show how to improve the approximation ratio achievable in polynomial time for BGD, from the previously known to for any > 0. Combined with the results in (Caprara, Journal of Combinatorial Optimization, vol. 3, pp. 149–182, 1999b), this yields the same approximation guarantee for n! – O((n – 5)!) out of the n! instances of SBR on permutations with n elements. Our result uses the best known approximation algorithms for Stable Set on graphs with maximum degree 4 as well as for Set Packing where the maximum size of a set is 6. Any improvement in the ratio achieved by these approximation algorithms will yield an automatic improvement of our result.     

Environmental and socioeconomic determinants of neonatal mortality in a northern Italian city in the early nineteenth century

Population and Environment - The research explores the effects of the environment on neonatal mortality in the early nineteenth century, controlling for social and economic factors. Individual...     

Summer temperature effects on deaths and hospital admissions among the elderly population in two Italian cities

In developed countries the effects of climate on health status are mainly due to temperature. Our analysis is aimed to deepen statistically the relationship between summer climate conditions and daily frequency of health episodes: deaths or hospital admissions. We expect to find a U-shaped relationship between temperature and frequencies of events occurring in summer regarding the elderly population resident in Milano and Brescia. We use as covariates hourly records of temperature recorded at observation sites located in Milano and Brescia. The analysis is performed using Generalized Additive Models (GAM), where the response variable is the daily number of events, which varies as a possibly non-linear function of meteorological variables measured on the same or previous day. We consider separate models for Milano and Brescia and then we compare temperature effects among the two towns and among different age classes. Moreover we consider separate models for all diagnosed events, for those due to respiratory disease and those due to circulatory pathologies. Model selection is a central problem, the basic methods used are the UBRE and GCV criteria but, instead of conditioning all final conclusions on the best model according to the chosen criterion, we investigated the effect of model selection by implementing a bootstrap procedure.     

The labour division of Italian couples after a birth: assessing the effect of unobserved heterogeneity

The results of previous studies on the effect of childbearing on both parents’ paid and unpaid work suffer from the difficulty related to the specification of latent variables that influence the relationship between reproductive behaviour of the couple and working activity. The aim of this study is to estimate the effect of transition to parenthood on the partners’ division of labour by accounting for latent variables, such as the bargaining process between partners and endogenous fertility decisions. In particular, this is the first time that our specific estimation strategy has been applied to determine the impact of childbearing on the division of household labour between partners taking into account the reverse causality effect between labour and fertility decisions. We use longitudinal data on married or cohabiting Italian couples provided by the Italian panel survey of the Generation and Gender Program. Our results are consistent with previous studies, and show that the birth of a child affects a woman’s unpaid labour strongly and positively and her paid labour negatively, while men’s work is mostly unaffected. Moreover, when partners hold traditional attitudes regarding gender roles and the family, the female partner is even more strongly affected by childbearing in terms of total amount of labour (paid plus unpaid). However, our sensitivity analysis shows that these results appear only when our correction strategy for the misspecification of latent variables is applied.

     

The seasonality of conception

Individual data on menstrual cycles of noncontracepting women living in Western countries were used in order to verify whether the biological seasonality of conception persists after sexual behavior is controlled for. Episodes of intercourse were recorded daily, and the time of ovulation was detected by a marker We find that the seasonality of conception changes with woman's age and frequency of episodes of sexual intercourse. In particular; for women aged 27-31 having only one act of intercourse during the six most fertile days of the menstrual cycle, the seasonality of fecundability is stronger In this age group in the Northern Hemisphere, if seasonality of acts of sexual intercourse is controlled, the monthly distribution of probability of conception is bimodal, with two maxima (September and January) and two minima (December and March). When unobserved characteristics of the couples are considered, this seasonal pattern of conception persists.     

Analysis of heat wave effects on health by using generalized additive model and bootstrap-based model selection

Summary.  It is known that high summer temperature may lead to worsening health conditions among fragile individuals within exposed populations. It is also argued that multiday patterns of high temperature—heat waves—may have relevant effects on health. We discuss the possible measures of intensities of heat waves to be included in a generalized additive model explaining the number of hospital admissions that occurred during summer months in Milan. The issue of variable selection is central to the analysis: a computational method is discussed which may help in assessing the robustness of the model selection method. Eventually, we obtain evidence supporting the relevance of heat waves in driving adverse health episodes.