754 research outputs found

    Progenitors of Supernovae Type Ia

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    Despite the significance of Type Ia supernovae (SNeIa) in many fields in astrophysics, SNeIa lack a theoretical explanation. The standard scenarios involve thermonuclear explosions of carbon/oxygen white dwarfs approaching the Chandrasekhar mass; either by accretion from a companion or by a merger of two white dwarfs. We investigate the contribution from both channels to the SNIa rate with the binary population synthesis (BPS) code SeBa in order to constrain binary processes such as the mass retention efficiency of WD accretion and common envelope evolution. We determine the theoretical rates and delay time distribution of SNIa progenitors and in particular study how assumptions affect the predicted rates.Comment: 6 pages, 6 figures, appeared in proceedings for "The 18th European White Dwarf Workshop

    The blackcap (Sylvia atricapilla) genome reveals a species-specific accumulation of LTR retrotransposons

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    Transposable elements are mobile genetic elements that have the ability to move around the genome, and as such can be a source of genome variability. Transposable elements (TEs) are ubiquitous and many are found within a wide variety of life. Based on their characteristics we can annotate TEs within the host genome and classify them into specific TE types and families. The increasing number of available high-quality genome references in recent years provides an excellent resource that will enhance the understanding of the role of recently active TEs on genetic variation and phenotypic evolution. Here we showcase this through a high-quality TE annotation of the Eurasian blackcap (Sylvia atricapilla), as our chromosome resolution reference genome allowed the reconstruction of difficult-to-assemble regions. We have the ability to distinguish species-specific and non-specific TEs. We investigate how these TE categories are distributed along the genome and evaluate their correlation with four genomic features: recombination rate, gene coverage, CpG island coverage and GC coverage. We found a marked difference between species-specific and non-specific TEs. While species-specific TEs were negatively correlated with both GC content and recombination rate, the correlation with recombination rate disappeared and turned positive for GC content when considering non-specific TEs

    The First Science Results from SPHERE: Disproving the Predicted Brown Dwarf around V471 Tau

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    Variations of eclipse arrival times have recently been detected in several post common envelope binaries consisting of a white dwarf and a main sequence companion star. The generally favoured explanation for these timing variations is the gravitational pull of one or more circumbinary substellar objects periodically moving the center of mass of the host binary. Using the new extreme-AO instrument SPHERE, we image the prototype eclipsing post-common envelope binary V471 Tau in search of the brown dwarf that is believed to be responsible for variations in its eclipse arrival times. We report that an unprecedented contrast of 12.1 magnitudes in the H band at a separation of 260 mas was achieved, but resulted in a non-detection. This implies that there is no brown dwarf present in the system unless it is three magnitudes fainter than predicted by evolutionary track models, and provides damaging evidence against the circumbinary interpretation of eclipse timing variations. In the case of V471 Tau, a more consistent explanation is offered with the Applegate mechanism, in which these variations are prescribed to changes in the quadrupole moment within the main-sequence sta

    Waste prevention and education in five european countries

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    Artigo desenvolvido no âmbito de uma Unidade Curricular que funcionou em rede entre várias Universidades Europeias. Este artigo foi desenvolvido num trabalho em rede desenvolvido entre estudantes de diversas universidade e que avaliaram a implementação da diretiva quadro de resíduos em diversos países da União Europeia e apresentarem um conjunto de recomendações para se uniformizar e melhorar a gestão de resíduos na Europa com a aplicação da hierarquia dos resíduos.This research assessed the different goals of the EU Waste Framework Directive (2008) concerning waste prevention in five countries of the EU. The countries under research are the home countries of the EVS group members: Austria, Belgium, Germany, Netherlands and Portugal. The research about the status quo of waste prevention revealed that waste preven-tion has not reached yet. All the countries have high recycling rates and low dumping rate, ex-cept Portugal. Although decoupling trends start to appear and the countries are climbing up the waste hierarchy, waste prevention is still a mountain too far. The EVS group also checked if education was included in the waste prevention programmes and education plays a very im-portant role. The group looked for good examples of waste prevention and analyzed them with SWOT. The examples are a success in the home countries and can be implemented in other EU or even worldwide countries.info:eu-repo/semantics/publishedVersio

    Psychological distress and lower health-related quality of life are associated with need for dietary support among colorectal cancer survivors with overweight or obesity

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    Objective: Two-third of colorectal cancer (CRC) survivors are overweight or obese. Psychological distress and low health-related quality of life (HRQoL) may be barriers to improving diet. We aimed to assess associations between psychological distress and HRQoL and the need for dietary support in CRC survivors with overweight or obesity. Methods: All alive individuals diagnosed with CRC between 2000 and 2009, as registered by the Dutch population-based Eindhoven Cancer Registry, were eligible for participation and received a questionnaire. Multivariable logistic regression analyses were conducted to assess associations between HRQoL (EORTC QLQ-C30), symptoms of anxiety and depression (HADS), and self-reported need for dietary support (single-item). Results: A total of 1458 completed the questionnaire (response rate 82%), and 756 (43%) had a BMI of 25.0 or higher and complete data on “need for dietary support” and were included for analyses. BMI ranged between 25.0 and 60.6 (mean, 28.9; SD, 3.6). The majority (71.7%) was overweight (BMI ≥ 25), and 28.3% obese (BMI ≥ 30). Twenty-one percent reported a need for dietary support which was associated with more psychological distress and lower HRQoL. Those who experienced symptoms of anxiety or depression were more likely to report a need for dietary support (27.6% and 28.7%) than those who did not experience symptoms of anxiety (12.3%; OR 2.02; 95% CI 1.22–3.35) or depression (13.5%; OR 1.96; 95% CI 1.19–3.22). Conclusions: Results suggest that psychological distress and lower HRQoL should be taken into account while promoting a healthy diet in overweight or obese CRC survivors since these factors may hinder adherence to a healthy diet.</p

    Pseudo Identities Based on Fingerprint Characteristics

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    This paper presents the integrated project TURBINE which is funded under the EU 7th research framework programme. This research is a multi-disciplinary effort on privacy enhancing technology, combining innovative developments in cryptography and fingerprint recognition. The objective of this project is to provide a breakthrough in electronic authentication for various applications in the physical world and on the Internet. On the one hand it will provide secure identity verification thanks to fingerprint recognition. On the other hand it will reliably protect the biometric data through advanced cryptography technology. In concrete terms, it will provide the assurance that (i) the data used for the authentication, generated from the fingerprint, cannot be used to restore the original fingerprint sample, (ii) the individual will be able to create different "pseudo-identities" for different applications with the same fingerprint, whilst ensuring that these different identities (and hence the related personal data) cannot be linked to each other, and (iii) the individual is enabled to revoke an biometric identifier (pseudo-identity) for a given application in case it should not be used anymore

    Knowledge of pressure ulcer prevention: a cross-sectional and comparative study among nurses

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    BACKGROUND: Pressure ulcers are a common, painful and costly condition. Results of a 1991 study into the knowledge among Dutch hospital nurses on the usefulness of measures to prevent pressure ulcers showed moderate knowledge. Results were confirmed by subsequent studies. In recent years, Dutch guidelines have been updated and the attention given to pressure ulcer care has been increased. This was expected to improve pressure ulcer care and to increase nurses' knowledge. The aims of the current study were to investigate (1) how much nurses employed in Dutch hospitals know about the usefulness of 28 preventive measures considered in the most recent national pressure ulcer guideline; (2) whether differences in knowledge exist between nurses working in hospitals that audit pressure ulcers and those employed in hospitals that do not; and (3) to study whether knowledge among Dutch hospital nurses regarding the usefulness of preventive measures had changed between 1991 and 2003. METHODS: A cross-sectional study design among nurses employed in Dutch hospitals in 2003 was used to investigate their knowledge and differences in knowledge between nurses employed in different types of institution. A comparative design was used to assess whether knowledge differed between this population and that of Dutch hospital nurses in 1991. The nurses' knowledge was assessed by a written questionnaire. Data of 522 respondents meeting the inclusion criteria were analyzed and compared with the results of the 351 nurses included in the 1991 study. RESULTS: Knowledge in 2003 was slightly better than that in 1991. The nurses were moderately aware of the usefulness of preventive measures. Nurses employed in organizations that monitored pressure ulcers did not display greater knowledge than those employed in organizations that did not do so. CONCLUSION: Knowledge among Dutch hospital nurses about the usefulness of measures to prevent pressure ulcers seems to be moderate. Being employed in an institution that monitors pressure ulcer care hardly affects the knowledge level. Knowledge about prevention has improved little since 1991
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