1,778 research outputs found
Gravitational Wave Signatures of Highly Magnetized Neutron Stars
Motivated by the recent gravitational wave detection by the LIGO-VIRGO
observatories, we study the Love number and dimensionless tidal polarizability
of highly magnetized stars. We also investigate the fundamental quasi-normal
mode of neutron stars subject to high magnetic fields. To perform our
calculations we use the chaotic field approximation and consider both nucleonic
and hyperonic stars. As far as the fundamental mode is concerned, we conclude
that the role played by the constitution of the stars is far more relevant than
the intensity of the magnetic field and if massive stars are considered, the
ones constituted by nucleons only present frequencies somewhat lower than the
ones with hyperonic cores, a feature that can be used to point out the real
internal structure of neutron stars. Moreover, our studies clearly indicate
that strong magnetic fields play a crucial role in the deformability of low
mass neutron stars, with possible consequences on the interpretation of the
detected gravitational waves signatures.Comment: 24 pages, 4 figures, 6 table
Modelling environmental monitoring data coming from different surveys
Environmental monitoring networks are providing large amounts of spatio-temporal data. Air pollution data, as other environmental data, exhibit a spatial and a temporal correlated nature. To improve the accuracy of predictions at unmonitored locations, there is a growing need for models capturing those spatio-temporal correlations.
With this work, we propose a spatio-temporal model for gaussian data collected in a few number of surveys. We assume the spatial correlation structure to be the same in all surveys. In an application of this model to real data, concerning heavy metal concentrations in mosses collected from three surveys occurring between 1992 and 2002 in mainland Portugal, the data set is dense in the spatial dimension but sparse in the temporal one, thus our model-based approach corresponds to a saturated correlation model in the time dimension. A novel interpretation for the space-time covariance function is introduced. A simulation study, aiming to validate the model, provided better results in terms of accuracy with the novel covariance function.
Prediction maps of the observed variable for the most recent survey, and of the inter- polation error as a measure of accuracy, are presented.The authors thank the Centre of Environmental Biology of Lisbon University for permission to use the moss data. The authors acknowledge financial support from the Portuguese Funds through FCT (Fundacao para a Ciencia e a Tecnologia), within the Project UID/MAT/00013/2013.info:eu-repo/semantics/publishedVersio
Towards a Generic Trace for Rule Based Constraint Reasoning
CHR is a very versatile programming language that allows programmers to
declaratively specify constraint solvers. An important part of the development
of such solvers is in their testing and debugging phases. Current CHR
implementations support those phases by offering tracing facilities with
limited information. In this report, we propose a new trace for CHR which
contains enough information to analyze any aspects of \CHRv\ execution at some
useful abstract level, common to several implementations. %a large family of
rule based solvers. This approach is based on the idea of generic trace. Such a
trace is formally defined as an extension of the semantics of
CHR. We show that it can be derived form the SWI Prolog CHR trace
Modelling the live-electronics in electroacoustic music using particle systems
Developing the live-electronics for a contemporary electroacoustic piece is a complex process that normally involves the transfer of artistic and aesthetic concepts between the composer and the musical assistant. Translating in technical terms the musical, artistic and aesthetic concepts by means of algorithms and mathematical parameters is seldom an easy and straightforward task. The use of a particle system to describe the dynamics and characteristics of compositional parameters can reveal an effective way for achieving a significant relationship between compositional aspects and their technical implementation. This paper describes a method for creating and modelling a particle system based on compositional parameters and how to map those parameters into digital audio processes. An implementation of this method is described, as well as the use of such a method for the development of the work O Farfalhar das Folhas (The rustling of leaves) (2010), for one flutist, one clarinetist, violin, violoncello, piano and live-electronics, by Flo Menezes.info:eu-repo/semantics/publishedVersio
Physical Activity Patterns in Adults who are Deaf
The benefits of physical activity for health are well known, but there is limited information about its patterns in some disability groups. The main purpose of this study was to measure physical activity in a sample of adults who are Deaf. Sixty-two Deaf adults (18-65 years) from both genders (64.3% women) participated. Physical activity was measured by accelerometers worn near the right hip for at least three days. Twenty-nine (~59%) of the 49 participants that met the accelerometer criteria reached the recommendation of 30 min per day of moderate-to-vigorous PA. However, no one achieved that goal in bouts of at least 10 minutes. Participants spent 71% of the accelerometer wear time in sedentary behaviour. It seems that hearing impairment has a lower impact on physical activity habits than other types of disability. Nonetheless, the levels of physical activity could be improved among the Deaf community, especially considering the international recommendations that aerobic activities should be performed in bouts of at least 10 minutes. Future research should collect information on the main barriers and facilitators for physical activity in adults who are Deaf, and strategies should be implemented to promote their engagement in longer bouts of physical activity
Ectoparasitic flies (Diptera: Streblidae) on bats (Mammalia: Chiroptera) from a Private Natural Heritage Reserve in southeastern Brazil
Due to the small number of records of Streblidae on bats, despite extensive study on these mammals in the state of Rio de Janeiro, a survey was carried out in an area of the Atlantic Forest. The present study was carried out at Bom Retiro Farm Natural Heritage Private Reserve. We captured 401 bats of 17 species, 13 genera, and four families; bat flies infested 221 bats of only four species. Carollia perspicillata (Linnaeus, 1758) has the highest fly diversity, with seven fly species: Trichobius joblingi (Wenzel, 1966) (n = 23), Megistopoda proxima (Séguy, 1926) (n = 15), Strebla guajiro (García & Casal, 1965) (n = 15), Aspidoptera falcata (Wenzel, 1976) (n = 6) Paratrichobius longicrus (Miranda Ribeiro, 1907) (n = 8), Paraeuctenodes similis (Wenzel 1976) (n = 3), and Trichobius anducei (Guerrero, 1998) (n = 1). Two species infested Platyrrhinus lineatus (É. Geoffroy, 1810): Aspidoptera falcata (n = 1) and Anastrebla caudiferae (Wenzel, 1996) (n = 1). Paradyschiria parvula (Falcoz, 1931) (n = 11) infested Noctilio leporinus (Linnaeus, 1758) and M. proxima (n = 12) and Trichobius uniformis (Curran, 1935) (n = 1) infested Sturnira lilium (É. Geoffroy, 1842). Sturnira lilium has the highest infestation rate, with ten out of 46 captured individuals parasitized, followed by Carollia perspicillata, with 33 out of 164 captured parasitized, and by P. lineatus with only two parasitized individuals out of ten. Among 97 streblid flies captured, M. proxima was the most abundant (27.83%), followed by T. joblingi (23.71%), and S. guajiro (15.46%). All remaining bat fly species represented 33%. Paradichyria parvula has the first record for Rio de Janeiro State
Non extensive thermodynamics and neutron star properties
In the present work we apply non extensive statistics to obtain equations of
state suitable to describe stellar matter and verify its effects on microscopic
and macroscopic quantities. Two snapshots of the star evolution are considered
and the direct Urca process is investigated with two different parameter sets.
-values are chosen as 1.05 and 1.14. The equations of state are only
slightly modified, but the effects are enough to produce stars with slightly
higher maximum masses. The onsets of the constituents are more strongly
affected and the internal stellar temperature decreases with the increase of
the -value, with consequences on the strangeness and cooling rates of the
stars.Comment: 13 pages, 9 figures, 3 table
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