Low-mass pre--main-sequence stars in the Magellanic Clouds

[Abridged] The stellar Initial Mass Function (IMF) suggests that sub-solar stars form in very large numbers. Most attractive places for catching low-mass star formation in the act are young stellar clusters and associations, still (half-)embedded in star-forming regions. The low-mass stars in such regions are still in their pre--main-sequence (PMS) evolutionary phase. The peculiar nature of these objects and the contamination of their samples by the evolved populations of the Galactic disk impose demanding observational techniques for the detection of complete numbers of PMS stars in the Milky Way. The Magellanic Clouds, the companion galaxies to our own, demonstrate an exceptional star formation activity. The low extinction and stellar field contamination in star-forming regions of these galaxies imply a more efficient detection of low-mass PMS stars than in the Milky Way, but their distance from us make the application of special detection techniques unfeasible. Nonetheless, imaging with the Hubble Space Telescope yield the discovery of solar and sub-solar PMS stars in the Magellanic Clouds from photometry alone. Unprecedented numbers of such objects are identified as the low-mass stellar content of their star-forming regions, changing completely our picture of young stellar systems outside the Milky Way, and extending the extragalactic stellar IMF below the persisting threshold of a few solar masses. This review presents the recent developments in the investigation of PMS stars in the Magellanic Clouds, with special focus on the limitations by single-epoch photometry that can only be circumvented by the detailed study of the observable behavior of these stars in the color-magnitude diagram. The achieved characterization of the low-mass PMS stars in the Magellanic Clouds allowed thus a more comprehensive understanding of the star formation process in our neighboring galaxies.Comment: Review paper, 26 pages (in LaTeX style for Springer journals), 4 figures. Accepted for publication in Space Science Review

Childhood Maltreatment, Borderline Personality Features, and Coping as Predictors of Intimate Partner Violence

Intimate partner violence (IPV) is a serious mental and physical health concern worldwide. Although previous research suggests that childhood maltreatment increases the risk for IPV, the underlying psychological mechanisms of this relationship are not yet entirely understood. Borderline personality (BP) features may play an important role in the cycle of violence, being associated with interpersonal violence in both childhood and adult relationships. The present study investigated whether BP features mediate the relationship between childhood maltreatment and IPV, differentiating between perpetration and victimization, and taking maladaptive stress coping and gender into account. Self-reports on IPV, childhood trauma, BP features, and maladaptive stress coping were collected in a mixed (nonclinical and clinical) sample of 703 adults (n = 537 female, n = 166 male), using an online survey. A serial mediation analysis (PROCESS) was performed to quantify the direct effect of childhood maltreatment on IPV and its indirect effects through BP features and maladaptive coping. Childhood maltreatment severity significantly positively predicted IPV perpetration as well as victimization. BP features, but not coping, partially mediated this relationship. Follow-up analyses suggest that affective instability and interpersonal disturbances (e.g., separation concerns) play an important role in IPV perpetration, while interpersonal and identity disturbances may mediate the effect of childhood maltreatment on IPV victimization. In clinical practice, attention should be paid not only to histories of childhood abuse and neglect but also to BP features, which may be possible risk factors for IPV.Stress and Psychopatholog