Prospects of long-time-series observations from Dome C for transit search

The detection of transiting extrasolar planets requires high-photometric quality and long-duration photometric stellar time-series. In this paper, we investigate the advantages provided by the Antarctic observing platform Dome C for planet transit detections during its long winter period, which allows for relatively long, uninterrupted time-series. Our calculations include limiting effects due to the Sun and Moon, cloud coverage and the effect of reduced photometric quality for high extinction of target fields. We compare the potential for long time-series from Dome C with a single site in Chile, a three-site low-latitude network as well as combinations of Dome C with Chile and the network, respectively. Dome C is one of the prime astronomical sites on Earth for obtaining uninterrupted long-duration observations in terms of prospects for a high observational duty cycle. The duty cycle of a project can, however, be significantly improved by integrating Dome C into a network of sites.Comment: 10 pages, 9 figures, accepted by PAS

Marital Histories and Economic Well-Being

Compared to unmarried individuals married individuals report greater average wealth. A restricted focus on current marital status risks misrepresenting the effects of marriage on wealth, as an increasing proportion of older adults have been divorced and remarried, having lived through the dramatic upheavals in family structure from the 1960s through the 1980s. To shed light on the associations between a lifetime of marriage events and wealth near retirement, we used panel data from the Health and Retirement Study and developed categories of marital experiences that acknowledged current status, type, number and date of past marital disruptions and total duration of time spent married across the lifespan. We found that the route individuals took to get to their current marital status were important predictors of wealth levels near retirement and were different for males and females. Observable differences in lifetime earnings, mortality risk, risk aversion, other characteristics such as education and number of children, explained much of the wealth difference between married and remarried individuals however neither observable characteristics nor sources of other wealth from pensions and Social Security were enough to explain the large differences in wealth accumulation between single and married women and individuals experiencing more than one marital disruption. Given the higher divorce rate, prevalence of multiple divorces and earlier age of divorce of the Baby Boomer cohort compared to earlier cohorts, an understanding of how marriage disruptions over the lifecycle impact savings is increasingly important for understanding the economic security of retirees.

Clouds in the atmospheres of extrasolar planets. IV. On the scattering greenhouse effect of CO2 ice particles: Numerical radiative transfer studies

Owing to their wavelengths dependent absorption and scattering properties, clouds have a strong impact on the climate of planetary atmospheres. Especially, the potential greenhouse effect of CO2 ice clouds in the atmospheres of terrestrial extrasolar planets is of particular interest because it might influence the position and thus the extension of the outer boundary of the classic habitable zone around main sequence stars. We study the radiative effects of CO2 ice particles obtained by different numerical treatments to solve the radiative transfer equation. The comparison between the results of a high-order discrete ordinate method and simpler two-stream approaches reveals large deviations in terms of a potential scattering efficiency of the greenhouse effect. The two-stream methods overestimate the transmitted and reflected radiation, thereby yielding a higher scattering greenhouse effect. For the particular case of a cool M-type dwarf the CO2 ice particles show no strong effective scattering greenhouse effect by using the high-order discrete ordinate method, whereas a positive net greenhouse effect was found in case of the two-stream radiative transfer schemes. As a result, previous studies on the effects of CO2 ice clouds using two-stream approximations overrated the atmospheric warming caused by the scattering greenhouse effect. Consequently, the scattering greenhouse effect of CO2 ice particles seems to be less effective than previously estimated. In general, higher order radiative transfer methods are necessary to describe the effects of CO2 ice clouds accurately as indicated by our numerical radiative transfer studies.Comment: accepted for publication in A&

Examinations of pathomechanisms in schizophrenic and bipolar disorders – results from two functional magnetic resonance imaging studies

Psychiatric disorders, in particular schizophrenia and bipolar disorder, affect the patients’ lives deeply on many levels and place a heavy burden on the healthcare system. The treatment of these diseases is often complicated and marked by many setbacks. Symptoms that have the strongest consequences for coping with everyday life are the impairments of cognitive performance, for example memory or attention deficits. Therefore, it is of great interest to better understand the underlying pathomechanisms to eventually improve treatment options for those patients. In this thesis two different fMRI studies were used to investigate the functional correlates of patients suffering from schizophrenia or bipolar disorder while performing a combined oddball-incongruence task and a reward associated task. Study A conducted a categorical comparison between bipolar and schizophrenia patients of the brain activation during an oddball and incongruence task. The results showed pathophysiological differences in the activation intensities between bipolar and schizophrenia patients as well as between the patient groups and healthy individuals. Overall it seems as if the brain activation severely depended on the task difficulty leading to compensatory hyperactivations in frontal brain areas of bipolar patients during the oddball task. Schizophrenia patients demonstrated low threshold hyperactivations in the intraparietal cortex compared to healthy controls. In the cognitively more demanding incongruence condition these compensatory mechanisms seemed to fail leading to hypoactivations in various brain regions such as the middle frontal gyrus or ventral pathway. Pilot study B searched retrospectively for functional markers which enable support vector machine algorithms predicting specific treatment response to typical and atypical antipsychotics as well as aripiprazole in a transnosological sample consisting of bipolar and schizophrenia patients. Consequently, (de-)activation differences between responders and non-responders in their respective treatment arm resulting from the desire-reason-dilemma paradigm were applied to support vector machine algorithms. The implementation of parameter estimates from deactivations of aripiprazole non-responders in brain regions partially associated with the default mode network, led to a successful treatment response prediction of patients receiving aripiprazole. Even though in future studies the sample sizes should be increased and monotherapeutical treatment ensured, this thesis already provides important insights on the pathomechanisms of bipolar disorder and schizophrenia patients or more specifically within the spectrum of both diseases. Prospectively, further studies can help to specify potential functional biomarkers which also might be able to predict treatment response and consequently approach personalized precision treatment in psychiatric disorders

The earliest English prose

This article examines the production of prose texts in pre-Alfredian England. After reviewing conventional ideas regarding the foundational role assigned to Alfred, king of Wessex, in the creation of the Old English prose genre, the discussion turns to a quite considerable number of non-poetic texts which were demonstrably produced at an earlier time, asking whether these can be regarded as prose. Following an investigation of the medieval and modern understanding of what constitutes prose, an argument is made for a more inclusive definition of this literary genre, one that does justice to the flourishing early literary culture especially of the kingdoms of Mercia and Kent. It is argued that the ninth-century prose productions of Alfred’s circles did present some innovation, but were clearly also based on earlier traditions and may to some extent have reacted against preceding compositional techniques and literary genres.Publisher PDFPeer reviewe