Probing dissipation mechanisms in BL Lac jets through X-ray polarimetry

The dissipation of energy flux in blazar jets plays a key role in the acceleration of relativistic particles. Two possibilities are commonly considered for the dissipation processes, magnetic reconnection -- possibly triggered by instabilities in magnetically-dominated jets -- , or shocks -- for weakly magnetized flows. We consider the polarimetric features expected for the two scenarios analyzing the results of state-of-the-art simulations. For the magnetic reconnection scenario we conclude, using results from global relativistic MHD simulations, that the emission likely occurs in turbulent regions with unstructured magnetic fields, although the simulations do not allow us to draw firm conclusions. On the other hand, with local particle-in-cell simulations we show that, for shocks with a magnetic field geometry suitable for particle acceleration, the self-generated magnetic field at the shock front is predominantly orthogonal to the shock normal and becomes quasi-parallel downstream. Based on this result we develop a simplified model to calculate the frequency-dependent degree of polarization, assuming that high-energy particles are injected at the shock and cool downstream. We apply our results to HBLs, blazars with the maximum of their synchrotron output at UV-soft X-ray energies. While in the optical band the predicted degree of polarization is low, in the X-ray emission it can ideally reach 50\%, especially during active/flaring states. The comparison between measurements in the optical and in the X-ray band made during active states (feasible with the planned {\it IXPE} satellite) are expected to provide valuable constraints on the dissipation and acceleration processes.Comment: 9 pages, 6 figures, accepted for publication by MNRA

Economics Conditions of Young Adults Before and After the Great Recession

Transition to adulthood has undoubtedly changed in the last few decades. For youth today, an important marker of adulthood is self-actualization in their professional career, and, consequently, also the achievement of stable financial conditions. Economic conditions of youth are greatly subject to fluctuations in the economy, and the subsequent governmental response. Using the Luxembourg Income Study, this work investigates the trends in income from work of young adults before and after the Great Recession of 2008 in five countries—US, UK, Norway, Germany, and Spain. The findings showed deterioration in economic conditions of young men, but with differences across countries. Young women suffered less from the crisis, and in some countries, their economic situation improved. The general negative trend was especially pronounced for those with high education, which is primarily because they stayed in education longer

Particle-in-cell simulations of shock-driven reconnection in relativistic striped winds

By means of two- and three-dimensional particle-in-cell simulations, we investigate the process of driven magnetic reconnection at the termination shock of relativistic striped flows. In pulsar winds and in magnetar-powered relativistic jets, the flow consists of stripes of alternating magnetic field polarity, separated by current sheets of hot plasma. At the wind termination shock, the flow compresses and the alternating fields annihilate by driven magnetic reconnection. Irrespective of the stripe wavelength "lambda" or the wind magnetization "sigma" (in the regime sigma>>1 of magnetically-dominated flows), shock-driven reconnection transfers all the magnetic energy of alternating fields to the particles, whose average Lorentz factor increases by a factor of sigma with respect to the pre-shock value. In the limit lambda/(r_L*sigma)>>1, where r_L is the relativistic Larmor radius in the wind, the post-shock particle spectrum approaches a flat power-law tail with slope around -1.5, populated by particles accelerated by the reconnection electric field. The presence of a current-aligned "guide" magnetic field suppresses the acceleration of particles only when the guide field is stronger than the alternating component. Our findings place important constraints on the models of non-thermal radiation from Pulsar Wind Nebulae and relativistic jets.Comment: 25 pages, 14 figures, movies available at https://www.cfa.harvard.edu/~lsironi/sironi_movies.tar ; in press, special issue of Computational Science and Discovery on selected research from the 22nd International Conference on Numerical Simulation of Plasma

Dimensions of sexual orientation and sleep disturbance among young adults

We examined associations among 3 dimensions of sexual orientation (identity, attraction, and behavior) and sleep disturbance among young adults in the United States. Using Wave IV of the National Longitudinal Study of Adolescent Health (respondents aged 24-32, N = 14,334), we ran multivariate logistic regressions to estimate the probability of reporting trouble falling asleep, trouble staying asleep, and short sleep duration, based on specific sexual orientation categories. Results after controlling for mental health indicate that these categories are more likely to have trouble falling asleep: women who identify as "bisexual" (OR = 1.85, CI: 1.21,2.82), women attracted to "both sexes" (OR = 1.31, CI: 1.00,1.72), women who have had "mostly opposite sex" partners (OR = 1.40, CI: 1.10,1.77), and men who have had "mostly same sex" partners (OR = 2.28, CI: 1.21,4.31). For trouble staying asleep: women who identify as "bisexual" (OR = 1.48, CI: 1.01,2.18), men and women attracted to "both sexes" (OR = 1.81, CI: 1.12,2.91; OR = 1.27, CI: 1.00,1.60), and women who have had "mostly opposite sex partners" (OR = 1.38, CI: 1.13,1.69). For short sleep duration: women who identify as "mostly straight" or "mostly gay" (OR = 1.27, CI: 1.01,1.60; OR = 2.64, CI: 1.36,5.14), men who identify as "bisexual" (OR = 2.56, CI: 1.26,5.18), women attracted only to "same sex" (OR = 2.42, CI: 1.48,3.96), men attracted to "both sexes" (OR = 1.88, CI: 1.21,2.93), and women who have had "mostly same sex" partners (OR = 4.90, CI: 2.10,11.46). Given the variation in findings, it is necessary to analyze each sexual orientation dimension and the categories within each dimension to adequately understand sleep disturbances among sexual minority populations

Happiness, housework and gender inequality in Europe

Although the last few decades have seen a progressive increase of gender equality in almost all dimensions of society, roles concerning childcare and domestic work remain highly gender-specific. Gender division of labour within the family varies considerably within and across countries. Gender systems are likely to have an important impact on individuals' well-being. Improved gender equality has enhanced the general well-being of women, although its extent may depend on the context in which women live and operate. This work considers the effect of the unequal division of labour within the household, between women and their partners, on women's own subjective assessment of happiness. We conducted the analysis using the European Social Survey data. We included 26 European countries and explored, exploiting a multi-level model to investigate the determinants of, women's differing levels of happiness across countries. In particular, we examined the extent to which gender equality at the country level can explain variation in happiness at the individual level. © The Author 2010. Published by Oxford University Press. All rights reserved

Trends in the Economic Independence of Young Adults in the United States: 1973-2007

One of the major milestones of adulthood is achieving economic independence. Without sufficient income, young people have difficulty leaving their childhood home, establishing a union, or having children-or they do so at great peril. Using the National Longitudinal Survey, this article compares the employment and economic circumstances of young adults aged 22-30 in 1973, 1987, and 2007, and their possible determinants. The results show that achieving economic independence is more difficult now than it was in the late 1980s and especially in the 1970s, even for the older age groups (age 27-28). The deterioration is more evident among men. From the 1970s there has been convergence in the trajectories for the achievement of economic self-sufficiency between men and women, suggesting that the increase in gender parity, especially in education and labor market outcomes, is making their opportunities to be employed and to earn good wages more similar. This convergence also suggests that union formation increasingly may depend on a capacity to combine men's and women's wages

Sexual orientation and health behaviors among college students in Italy

Studies regarding sexual orientation and health behaviors have largely neglected the Italian context. This research utilizes the second wave of the ‘Sexual and Emotional Life of Youths’ (SELFY) data set to compare the health behaviors of sexual minority (SM) and heterosexual college students in Italy. Results showed that bisexual women were more likely than heterosexual women to smoke both 1–7 and 8+ cigarettes per day, get drunk sometimes and often/very often, and use marijuana and/or ecstasy sometimes and often/very often. Homosexual women were more likely than heterosexual women to smoke 1–7 cigarettes per day, get drunk often/very often, and use marijuana and/or ecstasy often/very often. Homosexual men were more likely than heterosexual men to smoke 8+ cigarettes per day, but less likely to get drunk often/very often. Bisexual men were less likely than heterosexual men to participate in physical activity sometimes, often, and very often. Finally, bisexual men were less likely to exercise often than homosexual men. This work highlights that SM college students in Italy, particularly women, are more likely to engage in specific risky health behaviors compared to their heterosexual counterparts. More attention needs to be given to SMs in Italy to inform the Italian national health care system and to ensure that the appropriate care can be provided when required

Leaving home, moving to college, and returning home: Economic outcomes in the United States

Leaving the parental home is a milestone in the transition to adulthood. Historical changes in leaving home have been well documented in the literature. However, research investigating the consequences associated with the timing and pathway of leaving (and returning) home is still scant. Building mainly on capital accumulation and life course theories, we analyse data from the National Longitudinal Survey of Youth 1997 on young Americans born between 1980 and 1984, who are 27–31 years old in 2011. We find an M‐shaped relationship between age at leaving home and working and economic conditions later on: Leaving “too early,” “too late,” or at nonnormative ages is negatively associated with labour market outcomes. Also, among those who have been enrolled in college, leaving home to go to college, during college, or after college is positively associated with subsequent income, compared with leaving before college. Moving back in with parents is negatively associated with economic outcomes

Do couples who use fertility treatments divorce more? Evidence from the US National Survey of Family Growth

BACKGROUND Undertaking fertility treatment is a stressful process and may lead to couple instability, but high levels of couple satisfaction have usually been observed during or just after treatment. However, the evidence on divorce is scarce. OBJECTIVES We investigated the association between the use of a wide range of fertility treatments and marital dissolution in a representative sample of American women in their first marriage. METHODS We applied discrete-time event history analysis to data from the US National Survey of Family Growth (NSFG), collected from 2002 through 2013‒2015, to compare divorce rates among women who experienced successful treatments or unsuccessful treatments and a natural birth or no birth within the marriage (N = 13,784). RESULTS Women who used fertility treatments had a lower risk of divorce up to 20 years after the marriage, compared to the other groups. The probability was especially low when the treatment was successful, but women who did not conceive after the treatment also showed a lower risk of divorce. CONCLUSION We found evidence that undertaking fertility treatment is associated with a lower risk of divorce, suggesting that it might strengthen couples’ relationships. The sociodemographic characteristics of couples undertaking treatment partly explained the association, but we were not able to control for the quality of the relationship before the treatment, which is likely to play a role