Asteroseismology and Interferometry

Asteroseismology provides us with a unique opportunity to improve our understanding of stellar structure and evolution. Recent developments, including the first systematic studies of solar-like pulsators, have boosted the impact of this field of research within Astrophysics and have led to a significant increase in the size of the research community. In the present paper we start by reviewing the basic observational and theoretical properties of classical and solar-like pulsators and present results from some of the most recent and outstanding studies of these stars. We centre our review on those classes of pulsators for which interferometric studies are expected to provide a significant input. We discuss current limitations to asteroseismic studies, including difficulties in mode identification and in the accurate determination of global parameters of pulsating stars, and, after a brief review of those aspects of interferometry that are most relevant in this context, anticipate how interferometric observations may contribute to overcome these limitations. Moreover, we present results of recent pilot studies of pulsating stars involving both asteroseismic and interferometric constraints and look into the future, summarizing ongoing efforts concerning the development of future instruments and satellite missions which are expected to have an impact in this field of research.Comment: Version as published in The Astronomy and Astrophysics Review, Volume 14, Issue 3-4, pp. 217-36

Interaction Between Convection and Pulsation

This article reviews our current understanding of modelling convection dynamics in stars. Several semi-analytical time-dependent convection models have been proposed for pulsating one-dimensional stellar structures with different formulations for how the convective turbulent velocity field couples with the global stellar oscillations. In this review we put emphasis on two, widely used, time-dependent convection formulations for estimating pulsation properties in one-dimensional stellar models. Applications to pulsating stars are presented with results for oscillation properties, such as the effects of convection dynamics on the oscillation frequencies, or the stability of pulsation modes, in classical pulsators and in stars supporting solar-type oscillations.Comment: Invited review article for Living Reviews in Solar Physics. 88 pages, 14 figure

Safeguarding pollinators and their values to human well-being

Wild and managed pollinators provide a wide range of benefits to society in terms of contributions to food security, farmer and beekeeper livelihoods, social and cultural values, as well as the maintenance of wider biodiversity and ecosystem stability. Pollinators face numerous threats, including changes in land-use and management intensity, climate change, pesticides and genetically modified crops, pollinator management and pathogens, and invasive alien species. There are well-documented declines in some wild and managed pollinators in several regions of the world. However, many effective policy and management responses can be implemented to safeguard pollinators and sustain pollination services

In vitro hypoxia-conditioned colon cancer cell lines derived from HCT116 and HT29 exhibit altered apoptosis susceptibility and a more angiogenic profile in vivo

Hypoxia is an important selective force in the clonal evolution of tumours. Through HIF-1 and other transcription factors combined with tumour-specific genetic alterations, hypoxia is a dominant factor in the angiogenic phenotype. Cellular adaptation to hypoxia is an important requirement of tumour progression independent of angiogenesis. The adaptive changes, insofar as they alter hypoxia-induced apoptosis, are likely to determine responsiveness to antiangiogenic strategies. To investigate this adaptation of tumour cells to hypoxia, we recreated in vitro the in vivo situation of chronic intermittent exposure to low-oxygen levels. The colon carcinoma cell lines HT29 and HCT116 were subjected to 40 episodes of sublethal hypoxia (4 h) three times a week. The resulting two hypoxia-conditioned cell lines have been maintained in culture for more than 2 years. In both cell lines changes in doubling times occurred: in HT29 an increase, and in HCT116 a decrease. Cell survival in response to hypoxia and to DNA damage differed strikingly in the two cell lines. The HT29 hypoxia-conditioned cells were more resistant than the parental line to a 24 h hypoxic challenge, while those from HCT116 surprisingly were more sensitive. Sensitivity to cisplatin in vitro was also significantly different for the hypoxia-conditioned compared with the parental lines, suggesting a change in pathways leading to apoptosis following DNA damage signaling. The growth of both conditioned cell lines in vivo as xenografts in immunodeficient (SCID) mice was more rapid than their parental lines, and was accompanied in each by evidence of enhanced vascular proliferation as a consequence of the hypoxia-conditioning. Thus the changes in apoptotic susceptibility were independent of altered angiogenesis. The derivation of these lines provides a model for events within hypoxic regions of colon cancers, and for the acquisition of resistance and sensitivity characteristics that may have therapeutic implications for the use of antiangiogenesis drugs

Effectiveness of depression and anxiety prevention in adolescents with high familial risk: Study protocol for a randomized controlled trial

Contains fulltext : 121611.pdf (publisher's version ) (Open Access)Background: Depression and anxiety disorders during adolescence can have detrimental consequences. Both disorders are related to negative outcome in various areas during adolescence and are also predictive of depression and anxiety disorders later in life. Especially parental psychopathology and being female are risk factors that increase the probability of developing one of these disorders during adolescence. Research has shown that prevention programs have promising results, especially for adolescents who have these risk factors. Therefore, in this study, we will focus on the effectiveness of a prevention program ‘A jump forward’ that has been developed for adolescent girls with a familial risk of depression and/or anxiety. Methods/Design: We designed a randomized controlled trial to test the effectiveness of an indicated and selective prevention program aimed at depression and anxiety in adolescent girls. Adolescents aged between 11 and 15 years old with depressive and/or anxiety symptoms and with parents who show indicators of parental psychopathology will be randomly assigned to the experimental (N = 80) or control groups (N = 80). Participants in the experimental group will follow a preventive intervention, consisting of six sessions of 90 minutes each. All participants will complete baseline, intervention phase 1 (after session 2), intervention phase 2 (after session 4), post-intervention, 6 month follow-up, and 12 month follow-up assessments. Furthermore, parents will be asked to complete assessments at baseline, post-intervention, and 12-month follow-up. Primary outcome will be depressive symptoms. Secondary outcomes will be anxiety symptoms, suicidal ideation, response style, negative cognitive errors, parental emotional support and parental control, parental psychopathology, parenting stress and adolescents’ depression and anxiety symptoms according to the parents. Discussion: This paper described the study designed to evaluate a program for preventing depression and/or anxiety in high-risk adolescents over a 12-month follow-up period. If the program showed to be effective in reducing symptoms of depression and anxiety and preventing adolescents from developing clinical levels of these disorders, our results would be relevant to practice. Thus, the intervention could be used on a large scale. Moreover, this study aims to contribute to the evidence-based prevention of depression and anxiety of adolescents.7 p