Connectivity‐informed adaptive regularization for generalized outcomes

One of the challenging problems in neuroimaging is the principled incorporation of information from different imaging modalities. Data from each modality are frequently analyzed separately using, for instance, dimensionality reduction techniques, which result in a loss of mutual information. We propose a novel regularization method, generalized ridgified Partially Empirical Eigenvectors for Regression (griPEER), to estimate associations between the brain structure features and a scalar outcome within the generalized linear regression framework. griPEER improves the regression coefficient estimation by providing a principled approach to use external information from the structural brain connectivity. Specifically, we incorporate a penalty term, derived from the structural connectivity Laplacian matrix, in the penalized generalized linear regression. In this work, we address both theoretical and computational issues and demonstrate the robustness of our method despite incomplete information about the structural brain connectivity. In addition, we also provide a significance testing procedure for performing inference on the estimated coefficients. Finally, griPEER is evaluated both in extensive simulation studies and using clinical data to classify HIV+ and HIV? individuals.     

An Assessment of the Italian 2007 Complementary Social Security Reform: A Simulation Approach

In this paper we aim at assessing the outcomes of the 2007 Italian reform of the complementary social security scheme and at identifying the determinants behind them. The reform provided workers with relevant incentives to switch the investment of about 7 per cent of their gross yearly wages from a firm‐managed scheme (which took the form of a termination indemnity payment, the Trattamento di Fine Rapporto scheme) to an external pension fund. We provide a theoretical framework to model the workers' problem of choosing between these two different forms of complementary social security schemes and we then perform an agent‐based simulation taking into account all the details of the reform. Differently from previous contributions, we stress the impact that the investment decision has on the financial health of firms and, consequently, on workers' employment stability. Our simulations are able to replicate the Italian data in terms of adhesion rates to complementary social security and also to identify some of the key determinants of that outcome, such as fiscal incentives, individual preferences, the working of both the Italian labour and the financial markets and the productive structure of the Italian economy.     

Nearly Gaussian Distributions and Application

We consider the random variable X that is not Gaussian but for which X ^c , where c = (2k + 1)/(2j + 1) with k, j ? {0, 1,…}, is approximately Gaussian. A variable of this type is used to model the errors made by meteorologists when forecasting temperatures.     

Job Quality and Employment of Older People in Europe

We study the relationship between job quality and retirement using data from the Survey of Health, Ageing and Retirement in Europe, a longitudinal survey covering individuals aged 50+ in several European countries. Although most previous studies looked at the impact of bad working conditions on retirement intentions, we can use the panel dimension to study actual retirement as well as other pathways out of a job. As indicators for job quality we use three different approaches: overall job satisfaction, over‐ and undereducation for a particular job as well as effort–reward imbalance, which measures the imbalance between a worker's effort and the rewards he or she receives in turn. The analysis gives some evidence that poor job quality decreases retirement age, in particular for women.     

An fMRI Study of Responses to Sexual Stimuli as a Function of Gender and Sensation Seeking: A Preliminary Analysis

Although sexual cues produce stronger neural activation in men than in women, mechanisms underlying this differential response are unclear. We examined the relationship of sensation seeking and the brain’s response to sexual stimuli across gender in 27 subjects (14 men, M = 25.2 years, SD = 3.6, 85.2% Caucasian) who underwent functional magnetic resonance imaging (fMRI) while viewing sexual and nonsexual images. Whole-brain corrected significant clusters of regional activation were extracted and associated with gender, sensation seeking, and sexual behaviors. Men responded more to sexual than nonsexual images in the anterior cingulate/medial prefrontal cortex (ACC/mPFC), anterior insula/lateral orbitofrontal cortex, bilateral amygdala, and occipital regions. Sensation seeking related positively to ACC/mPFC (r = 0.65, p = 0.01) and left amygdala (r = 0.66, p = 0.01) response in men alone, with both of these correlations being significantly larger in men than in women (ps < 0.03). The relationship between brain responses and self-reported high-risk and low-risk sexual behaviors showed interesting, albeit nonsignificant, gender-specific trends. These findings suggest the relationship between sexual responsivity, sensation seeking, and sexual behavior is gender specific. This study indicates a need to identify the gender-specific mechanisms that underlie sexual responsivity and behaviors. In addition, it demonstrates that the nature of stimuli used to induce positive mood in imaging and other studies should be carefully considered.     

Life Course,Gender, and Participation in Voluntary Organizations in Italy

This article investigates the gender differences in participation in voluntary organizations across the life course in Italy. It shows that three forms of engagement in voluntary organizations—donating money, attending meetings, and doing unpaid work—may depend on some stages of the life course—leaving the parental home, forming a union, and becoming a parent—as it is plausible that they may change personal resources and pose constraints or provide opportunities for involvement. Using the household survey “ISTAT Multipurpose Survey—Aspects of daily life”, the article finds that while leaving the parental home is positively associated with both men’s and women’s involvement, forming a union, and being a parent is detrimental for women’s involvement and not for men’s. This pattern indicates that gender roles may constrain more women’s than men’s probability of participation in voluntary organizations.     

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Theory and Decision -