Hyperbolic formulations of General Relativity with Hamiltonian structure

With the aim of deriving symmetric hyperbolic free-evolution systems for GR that possess Hamiltonian structure and allow for the popular puncture gauge condition we analyze the hyperbolicity of Hamiltonian systems. We develop helpful tools which are applicable to either the first order in time, second order in space or the fully second order form of the equations of motion. For toy models we find that the Hamiltonian structure can simplify the proof of symmetric hyperbolicity. In GR we use a special structure of the principal part to prove symmetric hyperbolicity of a formulation that includes gauge conditions which are very similar to the puncture gauge.Comment: Our mathematica scripts are available at http://na.mathematik.uni-tuebingen.de/~richter

Hyperbolicity of Hamiltonian formulations in General Relativity

Well-posedness of the initial (boundary) value problem is an essential property, both of meaningful physical models and of numerical applications. To prove well-posedness of wave-type equations their level of hyperbolicity is an essential ingredient. We develop helpful tools and classify a large class of Hamiltonian versions of Einstein's equations with live gauge conditions with respect to their hyperbolicity. Finally we find a symmetric hyperbolic Hamiltonian formulation that allows for gauge conditions which are similar to the puncture gauge

Smoking behaviour and passive smoke exposure of adults – Results from GEDA 2019/2020-EHIS

Background: Smoking is a significant health risk and the leading cause of premature death. Passive smoke causes the same negative effects on health as smoking, albeit to a lesser extent. The reduction of tobacco consumption and the protection against passive smoke are thus important health objectives. Methods: The study German Health Update (GEDA 2019/2020-EHIS) is a cross-sectional telephone survey (04/2019 to 09/2020) of the resident population in Germany with questions relating to the current smoking behaviour and relating to the passive smoke exposure. The analysis sample comprises 22,708 persons from 18 years of age. Results: 24.0% of women and 33.9% of men from 18 years of age smoke currently, at least occasionally. Among both sexes, adults from 65 years of age smoke significantly more rarely than adults in the younger age groups. 4.1% of adults, who do not smoke themselves, are subjected daily to passive smoke exposure indoors. This affects in particular young adults and men. There are educational differences in tobacco consumption and in passive smoke exposure to the disadvantage of adults from lower educational groups. Conclusions: In Germany, there is still a need for action for effective measures for tobacco prevention, smoking cessation and tobacco control policy, which are effective in all population groups and which take into account the concerns of socially disadvantaged groups

Combining Multiband Remote Sensing and Hierarchical Distance Sampling to Establish Drivers of Bird Abundance

Information on habitat preferences is critical for the successful conservation of endangered species. For many species, especially those living in remote areas, we currently lack this information. Time and financial resources to analyze habitat use are limited. We aimed to develop a method to describe habitat preferences based on a combination of bird surveys with remotely sensed fine-scale land cover maps. We created a blended multiband remote sensing product from SPOT 6 and Landsat 8 data with a high spatial resolution. We surveyed populations of three bird species (Yellow-breasted Bunting Emberiza aureola, Ochre-rumped Bunting Emberiza yessoensis, and Black-faced Bunting Emberiza spodocephala) at a study site in the Russian Far East using hierarchical distance sampling, a survey method that allows to correct for varying detection probability. Combining the bird survey data and land cover variables from the remote sensing product allowed us to model population density as a function of environmental variables. We found that even small-scale land cover characteristics were predictable using remote sensing data with sufficient accuracy. The overall classification accuracy with pansharpened SPOT 6 data alone amounted to 71.3%. Higher accuracies were reached via the additional integration of SWIR bands (overall accuracy = 73.21%), especially for complex small-scale land cover types such as shrubby areas. This helped to reach a high accuracy in the habitat models. Abundances of the three studied bird species were closely linked to the proportion of wetland, willow shrubs, and habitat heterogeneity. Habitat requirements and population sizes of species of interest are valuable information for stakeholders and decision-makers to maximize the potential success of habitat management measures

Strongly hyperbolic Hamiltonian systems in numerical relativity: Formulation and symplectic integration

We consider two strongly hyperbolic Hamiltonian formulations of general relativity and their numerical integration with a free and a partially constrained symplectic integrator. In those formulations we use hyperbolic drivers for the shift and in one case also for the densitized lapse. A system where the densitized lapse is an external field allows to enforce the momentum constraints in a holonomically constrained Hamiltonian system and to turn the Hamilton constraint function from a weak to a strong invariant. These schemes are tested in a perturbed Minkowski and the Schwarzschild space-time. In those examples we find advantages of the strongly hyperbolic formulations over the ADM system presented in [arXiv:0807.0734]. Furthermore we observe stabilizing effects of the partially constrained evolution in Schwarzschild space-time as long as the momentum constraints are enforced.Comment: This version clarifies some points concerning the interpretation of the result

Rauchverhalten und Passivrauchbelastung Erwachsener – Ergebnisse aus GEDA 2019/2020-EHIS

Hintergrund: Rauchen ist ein bedeutendes Gesundheitsrisiko und die führende Ursache vorzeitiger Sterblichkeit. Passivrauch verursacht dieselben negativen gesundheitlichen Folgen wie das Rauchen, wenn auch in einem geringeren Ausmaß. Die Verringerung des Tabakkonsums und der Schutz vor Passivrauch sind daher wichtige gesundheitspolitische Ziele. Methode: Die Studie Gesundheit in Deutschland aktuell (GEDA 2019/2020-EHIS) ist eine telefonische Querschnittbefragung (04/2019 bis 09/2020) der in Deutschland lebenden Wohnbevölkerung mit Fragen zum aktuellen Rauchverhalten und zur Passivrauchbelastung. Die Analysestichprobe umfasst 22.708 Personen ab 18 Jahren. Ergebnisse: 24,0 % der Frauen und 33,9 % der Männer ab 18 Jahren rauchen aktuell, zumindest gelegentlich. Bei beiden Geschlechtern rauchen Erwachsene ab 65 Jahren deutlich seltener als Erwachsene in den jüngeren Altersgruppen. 4,1 % der Erwachsenen, die selbst nicht rauchen, sind täglich Passivrauchbelastung in geschlossenen Räumen ausgesetzt. Das betrifft besonders junge Erwachsene und Männer. Es bestehen Bildungsunterschiede im Tabakkonsum und in der Passivrauchbelastung zuungunsten von Erwachsenen aus unteren Bildungsgruppen. Schlussfolgerungen: In Deutschland besteht weiterhin Handlungsbedarf für eine effektive Maßnahmen der Tabakprävention, Rauchentwöhnung und Tabakkontrollpolitik, die in allen Bevölkerungsgruppen wirken und die Belange sozial benachteiligter Gruppen berücksichtige

Health-promoting behaviour among adults in Germany – Results from GEDA 2019/2020-EHIS

Health-promoting behaviours are important at any age to prevent diseases and to promote well-being. Using data from GEDA 2019/2020-EHIS, a Germany-wide, representative survey, this article describes how often the adult population in Germany reports certain types of health-promoting behaviour in their everyday lives. The behaviours considered are non-smoking, low-risk alcohol consumption, achievement of the World Health Organization’s (WHO) recommendations on aerobic physical activity, at least daily fruit and vegetable consumption, and maintaining a body weight within the normal range. This article describes the proportion of people who report these behaviours in their everyday lives by gender, age and education level, the number of health-promoting behaviours each person reports and the most common combinations in which they occur. Young adults between 18 and 29 years are most likely to achieve a health-promoting lifestyle. The proportion of people who report at least 150 minutes of physical activity per week and a normal body weight is lower in later adulthood than among 18- to 29-year-olds. The recommendation to eat fruit and vegetables daily is implemented least often of all five aspects of health behaviour under study. Finally, women are more likely to lead a health-promoting lifestyle than men.Health-promoting behaviours are important at any age to prevent diseases and to promote well-being. Using data from GEDA 2019/2020-EHIS, a Germany-wide, representative survey, this article describes how often the adult population in Germany reports certain types of health-promoting behaviour in their everyday lives. The behaviours considered are non-smoking, low-risk alcohol consumption, achievement of the World Health Organization’s (WHO) recommendations on aerobic physical activity, at least daily fruit and vegetable consumption, and maintaining a body weight within the normal range. This article describes the proportion of people who report these behaviours in their everyday lives by gender, age and education level, the number of health-promoting behaviours each person reports and the most common combinations in which they occur. Young adults between 18 and 29 years are most likely to achieve a health-promoting lifestyle. The proportion of people who report at least 150 minutes of physical activity per week and a normal body weight is lower in later adulthood than among 18- to 29-year-olds. The recommendation to eat fruit and vegetables daily is implemented least often of all five aspects of health behaviour under study. Finally, women are more likely to lead a health-promoting lifestyle than men.Peer Reviewe