Exomoon Habitability and Tidal Evolution in Low-Mass Star Systems

Discoveries of extrasolar planets in the habitable zone (HZ) of their parent star lead to questions about the habitability of massive moons orbiting planets in the HZ. Around low-mass stars, the HZ is much closer to the star than for Sun-like stars. For a planet-moon binary in such a HZ, the proximity of the star forces a close orbit for the moon to remain gravitationally bound to the planet. Under these conditions the effects of tidal heating, distortion torques, and stellar perturbations become important considerations for exomoon habitability. Utilizing a model that considers both dynamical and tidal interactions simultaneously, we performed a computational investigation into exomoon evolution for systems in the HZ of low-mass stars ($\lesssim 0.6\ M_{\odot}$). We show that dwarf stars with masses $\lesssim 0.2\ M_{\odot}$ cannot host habitable exomoons within the stellar HZ due to extreme tidal heating in the moon. Perturbations from a central star may continue to have deleterious effects in the HZ up to $\approx 0.5\ M_{\odot}$, depending on the host planet's mass and its location in the HZ, amongst others. In addition to heating concerns, torques due to tidal and spin distortion can lead to the relatively rapid inward spiraling of a moon. Therefore, moons of giant planets in HZs around the most abundant type of star are unlikely to have habitable surfaces. In cases with lower intensity tidal heating the stellar perturbations may have a positive influence on exomoon habitability by promoting long-term heating and possibly extending the HZ for exomoons.Comment: accepted by MNRAS, 20 pages, 8 figures in main text (7 col, 1 b/w

Doctor of Philosophy

dissertationCurrent technology and theoretical methods are allowing for the detection of sub-Earth sized extrasolar planets. In addition, the detection of massive moons orbiting extrasolar planets ("exomoons") has become feasible and searches are currently underway. Several extrasolar planets have now been discovered in the habitable zone (HZ) of their parent star. This naturally leads to questions about the habitability of moons around planets in the HZ. Red dwarf stars present interesting targets for habitable planet detection. Compared to the Sun, red dwarfs are smaller, fainter, lower mass, and much more numerous. Due to their low luminosities, the HZ is much closer to the star than for Sun-like stars. For a planet-moon binary in the HZ, the close proximity of the star presents dynamical restrictions on the stability of the moon, forcing it to orbit close to the planet to remain gravitationally bound. Under these conditions the effects of tidal heating, distortion torques, and stellar perturbations become important considerations to the habitability of an exomoon. Utilizing an evolution model that considers both dynamical and tidal interactions, I performed a computational investigation into long-term evolution of exomoon systems. My study focused on satellite systems in the HZ of red dwarf stars and the dependence of exomoon habitability on the mass of the central star. Results show that dwarf stars with masses < 0.2 M© cannot host habitable exomoons within the stellar HZ due to extreme tidal heating in the moon. These results suggest that a host planet could be located outside the stellar HZ to where higher tidal heating rates could act to promote habitability for an otherwise uninhabitable moon. Perturbations from a central star may continue to have deleterious effects in the HZ up to « 0.5 MSun, depending on the host planet's mass and its location in the HZ. In cases with lower intensity tidal heating, stellar perturbations may have a positive influence on exomoon habitability by promoting long-term heating rates above a minimum for habitable terrestrial environments. In addition to heating concerns, torques due to tidal and spin distortion can lead to the relatively rapid inward spiraling of a moon. The effects of torque and stability constraints also make it unlikely that long-term resonances between two massive moons will develop in the HZs around red dwarf stars. My study showed that moons in the circumstellar HZ are not necessarily habitable by definition. In addition, the HZ for an exomoon may extend beyond the HZ for an exoplanet. Therefore, an extended model is required when considering exomoon habitability in comparison to exoplanet habitability

Pesticide Use and Pest Management Practices for Major Crops in North Dakota - 2000

ER-79. This report summarizes the information on pesticide use as reported by the farmers surveyed. The data do not imply endorsement of any particular product or practice. Also, some responses may have misreported use of pesticides due to similar sounding chemical or trade names. In some cases, pesticides are approved for use before planting or after harvest, but not to a crop. The mention of an unregistered pesticide applied to a crop does not imply applications are legal or advocated by the authors. It is of the utmost importance that pesticide users READ, UNDERSTAND, and FOLLOW all label directions and precautions

Impacts of Strategic Grazing on Density and Ground Cover of Naturalised Hill Pasture

Low ground cover by perennial species is a major problem in naturalised pasture on steep hill country in southern Australia. This leads to water and nutrient runoff, recharge to groundwater, and soil erosion, all of which impact on the environmental sustainability and profitability of grazing enterprises. Restoration of perennial components, particularly the native grasses for these marginal land classes, is of great importance for improving water balance, halting land degradation (Ridley et al. 1997), extending growing season, and increasing pasture production. The objective of this study was to use strategic grazing management to increase the ground cover and plant population density of perennial species in steep hill country

Präoperative Nüchternzeiten: Sicht der Patienten

Zusammenfassung: Hintergrund: Mit dem Ziel der subjektiven perioperativen Qualitätsverbesserung scheint es wünschenswert, die präoperativen Nüchternzeiten im Rahmen der als sicher geltenden Grenzen so kurz als möglich zu halten. Diese Maßnahmen sollten mit einer messbaren Verminderung von präoperativem Hunger und Durst einhergehen und v.a. in einer Verbesserung der präoperativen Befindlichkeit resultieren. Welchen Einfluss Durst und Hunger aus Patientensicht auf den präoperativen Komfort haben, ist jedoch weit gehend unbekannt. Ziel dieser Studie war es, das Ausmaß der Beeinträchtigung der Patienten durch eine traditionelle Nüchternheitsregelung abzuschätzen. Patienten und Methoden: Ein Kollektiv von 412Patienten der "American-Society-of-Anesthesiologists"- (ASA-)RisikoklassenI und II, das sich einem kleineren chirurgischen Eingriff unterzog, wurde mithilfe eines Fragebogens zum Ausmaß und Stellenwert von präoperativem Durst und Hunger befragt. Ergebnisse: Es hatten 33% der Patienten mäßigen oder starken Durst, 19% mäßigen bis starken Hunger. Von den Befragten möchten 47% vor der Operation noch trinken, 72% hätten gern noch ein leichtes Frühstück eingenommen. Die mittlere Nüchternzeit war 12,8±3,4h für Flüssigkeiten und 15,5±4,4h für Essen. Durst wurde von 3,3% und Hunger von 0,8% der Patienten als Hauptgrund für die Beeinträchtigung des präoperativen Wohlbefindens genannt. Das lange Warten (8,5%), Nervosität (6,5%) und Angst (4,8%) wurden am häufigsten genannt. Die Antworten waren unabhängig von der Zeitdauer der präoperativen Nüchternheit. Schlussfolgerung: Der Patientenkomfort ist durch eine traditionelle Nüchternheitsregelung beeinträchtigt, und Minimierung der präoperativen Nüchternzeiten wird von den Patienten gewünscht. Anstrengungen mit dem Ziel der Reduktion von präoperativer Angst und Nervosität bergen jedoch zusätzliches großes Potenzial für eine Steigerung der perioperativen Behandlungsqualität aus Sicht der Patiente

Fulminant Cerebral Malaria in a Swiss Patient

Abstract : Malaria remains the most important parasitic disease worldwide. Falciparum malaria is a medical emergency and requires immediate diagnosis and treatment. Cerebral malaria is a rapidly progressive, potentially fatal complication of Plasmodium falciparum infection. This case, including post-mortem observations, histology, and laboratory diagnosis, emphasizes the necessity of appropriate advice regarding malaria prophylaxis before travel to an endemic area. Malaria should always be considered in the differential diagnosis of patients presenting with fever and/or nonspecific flu-like symptoms after traveling to endemic countrie

Identity Formation between Structure and Agency – How ‘Us’ and ‘Them’ Relates to Voting Behavior in Contexts of Electoral Realignment

Western Europe is experiencing growing levels of political polarization between parties of the New Left and the Far Right. In many countries, the socio-structural foundations of this divide (class, education, residence) are by now so clear that many interpret this divide as a fully mobilized new electoral cleavage. At the same time, observers have highlighted a growing fragmentation of party systems and the proliferation of new competitors. We suggest to make sense of these contradic- tory developments by focusing on the shared group identities that constitute the “glue” of cleavage formation translating grievances into political antagonisms. Our contribution relies on data from an original online survey fielded in France, Germany, the UK and Switzerland. Respondents an- swered questions on their sense of belonging to a series of social groups, electoral preferences and socio-demographics. On this basis, we are able to show – observationally – that socio-structural categories relate to both socio-economically (e.g. class) and socio-culturally (e.g. cosmopolitanism, lifestyle) connoted group identities, which divide New Left and Far Right voters in surprisingly similar ways across contexts. We then study the extent of social closure and political mobilization at the extremes of the new divide through the analysis of social networks, perceived group align- ments, and perceived representation. Our findings suggest that the new conflict is firmly rooted in socio-economic categories and at the societal level. Its political mobilization happens mostly via culturally connoted identities. What is more, social realignments and closure are highly similar across the four countries. This underscores that party competition remains rooted in structural an- tagonisms even as support for individual parties becomes more volatile. To detect this underlying similarity and stability, it is necessary to focus on voter alignments to ideological party blocs, rather than individual parties

Trends in Depressed Mood and Suicidal Behaviors Among Female High School Students Who Engaged in Physical Fighting

The objective of this article is to identify prevalence changes in depressed mood/suicidal behaviors among female high school students reporting physical fighting. This research analyzed the national combined data set of the Youth Risk Behavior Surveillance (YRBS) cross-sectional surveys from 2001 to 2015. Logistic regression analyzed the time trends. Two multiple logistic regression models were built. A quadratic trend was present with an initial decrease followed by an increase 2009 to 2015 (p < .001). The odds and severity of depressed mood/suicidal behaviors were greater among female youths with four or more fights and for other violent events, which were even greater when accounting for electronic bullying. The odds of depressed mood/suicidal behaviors among female adolescents engaged in physical fighting has been increasing with electronic bullying contributing to polyvictimization

Adult BMI change and risk of Breast Cancer: National Health and Nutrition Examination Survey (NHANES) 2005-2010

OBJECTIVE: Breast cancer is the second leading cause of cancer mortality among women in the developed world. This study assessed the association between occurrence of breast cancer and body mass index (BMI) change from age 25 to age closest to breast cancer diagnosis while exploring the modifying effects of demographic variables. METHODS: The National Health and Nutrition Examination Survey data were used. Women included were ≥50 years, not pregnant and without a diagnosis of any cancer but breast. The total sample included 2895 women (172 with breast cancer and 2723 controls with no breast cancer diagnosis). Multivariate logistic regression was used to estimate the OR and 95 % CIs and interaction evaluated by including an interaction term in the model. RESULTS: Women whose BMI increased from normal or overweight to obese compared to those who remained at a normal BMI were found to have a 2 times higher odds (OR = 2.1; 95 % CI 1.11-3.79) of developing breast cancer. No significant association was observed for women who increased to overweight. However, a more pronounced association was observed in non-Hispanic black women (OR = 6.6; 95 % CI 1.68-25.86) and a significant association observed when they increased from normal to overweight (OR = 4.2; 95 % CI 1.02-17.75). CONCLUSIONS: Becoming obese after age 25 is associated with increased risk of breast cancer in women over 50 years old, with non-Hispanic black women being at greatest risk