Coleman meets Schwinger

It is well known that spherical D-branes are nucleated in the presence of an external RR electric field. Using the description of D-branes as solitons of the tachyon field on non-BPS D-branes, we show that the brane nucleation process can be seen as the decay of the tachyon false vacuum. This process can describe the decay of flux-branes in string theory or the decay of quintessence potentials arising in flux compactifications.Comment: 5 pages, 2 figure

Parental Monitoring and Youth's Binge Behaviors: The Role of Sensation Seeking and Life Satisfaction

Framed within an ecological perspective of the onset of adolescent problem behaviors, the current study explored the joint role of parent-adolescents’ relationships and youth's individual factors in binge eating and drinking. Firstly, in line with pieces of research highlighting the beneficial impact of effective parenting on youth development, the present paper sought to enhance the knowledge about the positive influence of parental monitoring on youth's binge drinking and eating. Moreover, since literature evidenced that the explanatory mechanisms of the association between parental monitoring and binge behaviors are not fully explored, the study focused on the potential intervening role of sensation seeking and life satisfaction as mediators. The study design was cross-sectional and self-report questionnaires were administered among a population of 944 high school students (M = 16.35, SD = 1.31) living in Palermo (Italy). Path analysis showed that parental monitoring was directly and negatively related to both binge eating and binge drinking. Moreover, sensation seeking negatively mediated the relationships between parental monitoring and both binge behaviors, whereas life satisfaction only mediated between parental monitoring and binge eating. The current study provided data useful to understand the complex interrelations between intrapersonal (life satisfaction and personality trait, i.e. sensation seeking) and contextual factors (parent–child relationships) that may discourage or cause eating and alcohol use disorders among youth. Finally, implications for parents and practitioners working with youngsters were discussed

Finding RR Lyrae Stars with SkyMapper: an Observational Test

One of the major science goals of the SkyMapper Survey of the Southern Hemisphere sky is the determination of the shape and extent of the halo of the Galaxy. In this paper we quantify the likely efficiency and completeness of the survey as regards the detection of RR Lyrae variable stars, which are excellent tracers of the halo stellar population. We have accomplished this via observations of the RR Lyrae-rich globular cluster NGC 3201. We find that for single epoch uvgri observations followed by two further epochs of g, r imaging, as per the intended three-epoch survey strategy, we recover known RR Lyraes with a completeness exceeding 90%. We also investigate boundaries in the gravity-sensitive single-epoch two-color diagram that yield high completeness and high efficiency (i.e., minimal contamination by non-RR Lyraes) and the general usefulness of this diagram in separating populations.Comment: 10 pages, 5 figures, to appear in the Publications of the Astronomical Society of Australia (PASA), published by Cambridge University Pres

Perivascular adipose tissue as a relevant fat depot for cardiovascular risk in obesity

Obesity is associated with increased risk of premature death, morbidity, and mortality from several cardiovascular diseases (CVDs), including stroke, coronary heart disease (CHD), myocardial infarction, and congestive heart failure. However, this is not a straightforward relationship. Although several studies have substantiated that obesity confers an independent and additive risk of all-cause and cardiovascular death, there is significant variability in these associations, with some lean individuals developing diseases and others remaining healthy despite severe obesity, the so-called metabolically healthy obese. Part of this variability has been attributed to the heterogeneity in both the distribution of body fat and the intrinsic properties of adipose tissue depots, including developmental origin, adipogenic and proliferative capacity, glucose and lipid metabolism, hormonal control, thermogenic ability, and vascularization. In obesity, these depot-specific differences translate into specific fat distribution patterns, which are closely associated with differential cardiometabolic risks. The adventitial fat layer, also known as perivascular adipose tissue (PVAT), is of major importance. Similar to the visceral adipose tissue, PVAT has a pathophysiological role in CVDs. PVAT influences vascular homeostasis by releasing numerous vasoactive factors, cytokines, and adipokines, which can readily target the underlying smooth muscle cell layers, regulating the vascular tone, distribution of blood flow, as well as angiogenesis, inflammatory processes, and redox status. In this review, we summarize the current knowledge and discuss the role of PVAT within the scope of adipose tissue as a major contributing factor to obesity-associated cardiovascular risk. Relevant clinical studies documenting the relationship between PVAT dysfunction and CVD with a focus on potential mechanisms by which PVAT contributes to obesity-related CVDs are pointed out