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showing 10 items of 3178 documents
GW170817, General Relativistic Magnetohydrodynamic Simulations, and the Neutron Star Maximum Mass
2017
Recent numerical simulations in general relativistic magnetohydrodynamics (GRMHD) provide useful constraints for the interpretation of the GW170817 discovery. Combining the observed data with these simulations leads to a bound on the maximum mass of a cold, spherical neutron star (the TOV limit): ${M_{\rm max}^{\rm sph}}\lesssim 2.74/\beta$, where $\beta$ is the ratio of the maximum mass of a uniformly rotating neutron star (the supramassive limit) over the maximum mass of a nonrotating star. Causality arguments allow $\beta$ to be as high as $1.27$, while most realistic candidate equations of state predict $\beta$ to be closer to $1.2$, yielding ${M_{\rm max}^{\rm sph}}$ in the range $2.16…
Zvaigžņotā Debess: 2009/10, Ziema (206)
2009
Contents: TASS and Soviet Press materials. Flight of the Group of Three Soviet Spaceships ; Soviet and Foreign Press materials. Second Expedition on the Moon ; Č.Šklennik. Excursion to an Ancient Laboratory ; M.Gills. Opening Address ; Conference “Astronomy in Latvia” Programme ; From Presentation Abstracts ; I.Pundure. First Enterprise of this Kind ; N.Cimahoviča. Astronomical Contribution to Culture ; A.Alksnis. First Findings of Space Mission CoRoT ; I.Pundure. Ten Years of Chandra Hot Universe Exploration ; M.Gills. The Beginning of Autumn with Astronomy ; Buying Stars and Star Names (translation from IAU) ; I.Pundure. Arturs Balklavs and Astronomy of Latvia (1990-1997) ; J.Jaunbergs. A…
Fast Available Bandwidth sampling for ADSL links: rethinking the estimation for larger-scale measurements
2009
Most existing tools for measuring the end-to-end available bandwidth require access to both end-hosts of the measured path, which severely restricts their usability. Few tools have been developed to overcome this limitation, but all of them focus on achieving high precision and are not suitable for large campaigns. In this paper we develop FAB-Probe , a tool aimed at characterizing the available bandwidth of a large number of paths, adapting it particularly for ADSL settings. FAB-Probe is an evolution of ABwProbe , a tool that estimates the available bandwidth in non-cooperative ADSL environments. Analyzing carefully the needs of such a characterization tool, we optimize and rethink ABwProb…
Atmospheric aging of small-scale wood combustion emissions (model MECHA 1.0) – is it possible to distinguish causal effects from non-causal ass…
2020
Abstract. Primary emissions of wood combustion are complex mixtures of hundreds or even over a thousand compounds, which pass through a series of chemical reactions and physical transformation processes in the atmosphere (aging). This aging process depends on atmospheric conditions, such as concentration of atmospheric oxidizing agents (OH radical, ozone and nitrate radicals), humidity and solar radiation, and is known to strongly affect the characteristics of atmospheric aerosols. However, there are only few models that are able to represent the aging of emissions during its lifetime in the atmosphere. In this work, we implemented a model (Model for aging of Emissions in environmental CHAm…
2013
Abstract. Bioaerosols are relevant for public health and may play an important role in the climate system, but their atmospheric abundance, properties, and sources are not well understood. Here we show that the concentration of airborne biological particles in a North American forest ecosystem increases significantly during rain and that bioparticles are closely correlated with atmospheric ice nuclei (IN). The greatest increase of bioparticles and IN occurred in the size range of 2–6 μm, which is characteristic for bacterial aggregates and fungal spores. By DNA analysis we found high diversities of airborne bacteria and fungi, including groups containing human and plant pathogens (mildew, s…
2021
Background: University students encounter various stressors such as exam preparation, workload and economic concerns. Having to deal with a multitude of stressors can lead to mental health problems and have a negative impact on academic outcomes in students attending university. This paper describes the development and usability evaluation of an open and easily accessible online portal (me@JGU) designed to help students build skills they need to cope with common stressors and manage their own mental health. Methods: We developed a website that addresses the most common stressors among university students and offers strategies for dealing with difficult situations. Initial evaluation results…
Fundamental frequency of the female's voice: A cross-country empirical study on its influence on social and sexual selection
2020
Recent studies demonstrate that voice (in particular, its fundamental frequency -Fo-) may influence on social and sexual selection. Here, we tested how the Fo of female's voice is related to different aspects of social and sexual selection through a novel experimental approach. First, we recorded and measured the Fo of 22 women reading a neutral text in Spanish language. Six of these voices were selected and classified into three categories: voices with a low Fo (225 Hz). Then, these voices were rated by two independent samples including both men and women: one comprised of native Spanish-speakers (n = 683) and the other comprised of native Italian non-Spanish-speakers (n = 484). Contrarily…
Disadvantaged by Disability: Examining the Accessibility of Cyber Security
2021
Today, we are living in a digitally dependent world. Through the use of digital technologies, life is meant to be easier and streamlined. This includes giving access to services that previously were unavailable to many due to disability. Although technology has evolved immensely over the past few decades, reducing the digital divide, authentication methods have changed very little. Authentication is the forefront of securing users’ information, services and technology, yet for many it still poses issues in terms of usability and security, due to specific characteristics of different disabilities. In this paper, drawing upon a literature review, a review of recognized disabilities, and the r…
Predictability decomposition detects the impairment of brain-heart dynamical networks during sleep disorders and their recovery with treatment
2016
This work introduces a framework to study the network formed by the autonomic component of heart rate variability (cardiac process η ) and the amplitude of the different electroencephalographic waves (brain processes δ , θ , α , σ , β ) during sleep. The framework exploits multivariate linear models to decompose the predictability of any given target process into measures of self-, causal and interaction predictability reflecting respectively the information retained in the process and related to its physiological complexity, the information transferred from the other source processes, and the information modified during the transfer according to redundant or synergistic interaction betwee…
Garīgās brīvības veidošanās pusaudžiem skolā
1998
Advisor: Maija Pļaveniece