12,969 research outputs found
Developing a site-conditions map for seismic hazard Assessment in Portugal
The evaluation of site effects on a broad scale is a critical issue for seismic hazard and risk assessment, land use planning and emergency planning. As characterization of site conditions based on the shear-wave velocity has become increasingly important, several methods have been proposed in the literature to estimate its average over the first thirty meters (Vs30) from more extensively available data. These methods include correlations with geologic-geographic defined units and topographic slope. In this paper we present the first steps towards the development of a site–conditions map for Portugal, based on a regional database of shear-wave velocity data, together with geological, geographic, and lithological information. We computed Vs30 for each database site and classified it according to the corresponding geological-lithological information using maps at the smallest scale available (usually 1:50000). We evaluated the consistency of Vs30 values within generalized-geological classes, and assessed the performance of expedient methodologies proposed in the literature
Finite size analysis of a two-dimensional Ising model within a nonextensive approach
In this work we present a thorough analysis of the phase transitions that
occur in a ferromagnetic 2D Ising model, with only nearest-neighbors
interactions, in the framework of the Tsallis nonextensive statistics. We
performed Monte Carlo simulations on square lattices with linear sizes L
ranging from 32 up to 512. The statistical weight of the Metropolis algorithm
was changed according to the nonextensive statistics. Discontinuities in the
m(T) curve are observed for . However, we have verified only one
peak on the energy histograms at the critical temperatures, indicating the
occurrence of continuous phase transitions. For the regime, we
have found continuous phase transitions between the ordered and the disordered
phases, and determined the critical exponents via finite-size scaling. We
verified that the critical exponents , and depend
on the entropic index in the range in the form , and . On the other hand, the critical exponent does not
depend on . This suggests a violation of the scaling relations and and a nonuniversality of the
critical exponents along the ferro-paramagnetic frontier.Comment: accepted for publication in Phys. Rev.
Experimentally Witnessing the Quantumness of Correlations
The quantification of quantum correlations (other than entanglement) usually
entails laboured numerical optimization procedures also demanding quantum state
tomographic methods. Thus it is interesting to have a laboratory friendly
witness for the nature of correlations. In this Letter we report a direct
experimental implementation of such a witness in a room temperature nuclear
magnetic resonance system. In our experiment the nature of correlations is
revealed by performing only few local magnetization measurements. We also
compare the witness results with those for the symmetric quantum discord and we
obtained a fairly good agreement
Antenatal paternal adjustment and paternal attitudes after infertility treatment
STUDY QUESTION: Do mode of conception [ART versus Natural (NC)] and depression have an interactive effect on antenatal paternal adjustment and paternal attitudes?
SUMMARY ANSWER: Depression increased the negative effect of ART on antenatal paternal adjustment and paternal attitudes, specifically on antenatal marital relationship satisfaction.
WHAT IS KNOWN ALREADY: Research on antenatal paternal adjustment and paternal attitudes after ART is scarce and has produced inconsistent results.
STUDY DESIGN, SIZE, DURATION: This cross-sectional study assessed 197 primiparous men (71 ART and 126 NC) during their partner’s second trimester of gestation.
PARTICIPANTS/MATERIALS, SETTING, METHODS: Participants were derived from three larger longitudinal studies recruited at public Health Services in Northern Portugal. All men, for who this was their first child and had filled in a socio-demographic questionnaire, measures of depression and anxiety, and antenatal paternal adjustment and paternal attitudes were selected.
MAIN RESULTS AND THE ROLE OF CHANCE: An interaction effect of mode of conception and depression was found on antenatal paternal adjustment and paternal attitudes. ART men showing high depressive symptomatology had lower antenatal marital relationship satisfaction than ART men showing low depressive symptomatology and NC men showing high or low depressive symptomatology.
LIMITATIONS, REASONS FOR CAUTION: Due to the cross-sectional design of this study and the small sample size in the depression groups, the findings should be interpreted with caution.
WIDER IMPLICATIONS OF THE FINDINGS: Specialized psychological support should be available for ART men screened with high depressive symptomatology as part of routine prenatal care appointments.This study was conducted at Psychology Research Centre (UID/PSI/ 01662/2013), University of Minho, and at the Unidade de Investigação em Epidemiologia—Instituto de Saúde Pública da Universidade do Porto (EPIUnit) (UID/DTP/04750/2013). It was supported by the Foundation for Science and Technology (Portuguese Ministry of Education and Science) through National funds and co-financed by FEDER through COMPETE2020 under the PT2020 Partnership Agreement (POCI-01-0145-FEDER-007653) and through the Operational Programme Factors of Competitiveness–COMPETE within the project ‘Health, Governance and Accountability in Embryo Research: Couples’ Decisions About the Fates of Embryos’ (FCOMP-01-0124-FEDER-014453), the FCT Investigator contract IF/01674/2015 and PhD grants (SFRH/BD/115048/2016, SFRH/BD/75807/2011 and SFRH/BD/40146/2007).info:eu-repo/semantics/publishedVersio
Schwinger's Method for the Massive Casimir Effect
We apply to the massive scalar field a method recently proposed by Schwinger
to calculate the Casimir effect. The method is applied with two different
regularization schemes: the Schwinger original one by means of Poisson formula
and another one by means of analytical continuation.Comment: plain TeX, 6 pages, DFTUZ-93-2
Aneurysmal Degeneration of the Brachial Artery after Vascular Access Creation: Surgical Treatment Results
True peripheral artery aneurysms proximal to a longstanding arteriovenous fistula is a well-recognized complication. Late aneurysmal degeneration is rare. This study analyzed the characteristics, therapeutic options, and outcomes of true donor brachial artery aneurysms (DBAA) after arteriovenous fistula (AVF) for hemodialysis. We retrospectively collected the data of patients with DBAA after AVF creation, surgically repaired between January 2001 and September 2015. We excluded patients with pseudoaneurysms, anastomotic aneurysms, and infected aneurysms. We recorded patient's demographics, type of access, aneurysm characteristics, symptoms, treatment, and follow-up. Ten patients were treated for aneurysmal degeneration of the brachial artery. Average aneurysm diameter was 37.5 mm. All cases had, at least, one previous distal AVF, ligated or thrombosed, at the time of diagnosis. The first access was created in mean 137 months before the diagnosis of DBAA. Nine patients had previous medical history of renal transplant and were under immunosuppressive therapy. All patients were symptomatic at the time of diagnosis. In all cases, the treatment was aneurysmectomy followed by interposition bypass. One patient developed a postoperative hematoma with the need of surgical drainage. At 50 months of follow-up, one patient was submitted to percutaneous angioplasty due to an anastomotic stenosis. No other complications occurred during the entire follow-up period (mean: 69 months). The pathogenesis underlying DBAA remains unclear. Increased blood flow after AVF creation, immunosuppressive therapy, and ligation/thrombosis of the AVF may contribute to aneurysm formation. Surgical treatment by aneurysmectomy and bypass, with autogenous conducts, is a safe and effective option.info:eu-repo/semantics/publishedVersio
Crescimento e nutrição mineral de mudas de cedro Australiano (toona ciliata) sob omissão de nutrientes.
Com o objetivo de se avaliar as exigências nutricionais e o efeito da omissão de nutrientes no crescimento de mudas de cedro australiano (Toona ciliata M. Roem var. australis), foi realizado um experimento em casa de vegetação. Utilizou-se como substrato um Latossolo Vermelho Distroférrico, com baixa disponibilidade de nutrientes, utilizando-se 15 tratamentos, sob a técnica do elemento faltante. Foram aplicados dois tratamentos completos (um com fornecimento de N, P, K, S, B, Cu, Zn e aplicação de calcário e outro com o fornecimento de N, P, K, Ca, Mg, S, B, Cu e Zn, sem a aplicação de calcário), além da omissão de cada nutriente (-N, -P, -K, -Ca, -Mg, -S, -B, -Cu e -Zn), um tratamento com omissão conjunta de B, Cu e Zn, um tratamento com aplicação apenas de calcário, um tratamento com aplicação de N, P, K, S, B, Cu e Zn, sem aplicação de calcário e uma testemunha absoluta (solo natural). Foram avaliadas as seguintes caracterÃsticas: altura, diâmetro, matéria seca da parte aérea e das raÃzes, e teor de nutrientes na matéria seca da parte aérea, ao final de 150 dias. As plantas de cedro australiano apresentam elevada exigência nutricional, sendo que os nutrientes P, N, S, Ca, K, Mg e Cu, nessa ordem, foram limitantes ao crescimento das plantas. A omissão de B e Zn não afetou o crescimento das plantas. A aplicação de calcário foi essencial para o desenvolvimento das plantas de cedro australiano. O aparecimento dos primeiros sintomas de deficiência foi decorrente da omissão de: S, calcário e N
Environment-induced sudden transition in quantum discord dynamics
Non-classical correlations play a crucial role in the development of quantum
information science. The recent discovery that non-classical correlations can
be present even in separable (unentangled) states has broadened this scenario.
This generalized quantum correlation has been increasing relevance in several
fields, among them quantum communication, quantum computation, quantum phase
transitions, and biological systems. We demonstrate here the occurrence of the
sudden-change phenomenon and immunity against some sources of noise for the
quantum discord and its classical counterpart, in a room temperature nuclear
magnetic resonance setup. The experiment is performed in a decohering
environment causing loss of phase relations among the energy eigenstates and
exchange of energy between system and environment, resulting in relaxation to a
Gibbs ensemble
The impact of influencer marketing and instagrammers on consumer purchase intentions and brand attitude
In the last few years, we have noticed the emergence of influencer marketing (Lanz,
Goldenberg, Shapira, and Stahl, 2019; Sokolova and Kefi, 2019), specifically of how some
of this arising-stars in the social media spectrum have become sources of advice for other
consumers, resulting in opinion leaders for the brands they advocate (Casaló, Flavián, and
Ibáñez-Sánchez, 2018). As this trend is expected to continue in the near future, the
current research focuses in one of the fastest-growing social media platforms - Instagram
- (De Veirman, Cauberghe, and Hudders, 2017; Sheldon, Rauschnabel, Antony, and Car,
2017) to understand how Instagrammers and their posts have an impact on consumer’s
purchase decisions for the young-adult audiences. Additionally, this study also aims to
understand if this content creation influences consumer’s brand attitude (Faircloth,
Capella, and Alford, 2016), that is, in the consumer’s opinion about a product or service of
a specific brand.info:eu-repo/semantics/publishedVersio
A familial partial AZFb-c microdeletion associated with diferente fértile phenotypes
After the Klinefelter syndrome, Y chromosome microdeletions are the second most frequent genetic cause of spermatogenic failure resulting in male infertility. Y chromosome microdeletions, encompassing one or more of the three AZF regions, are associated with diverse testicular histology, ranging from Sertoli-cell-only syndrome (AZFa del), maturation arrest (AZFb del) to hypospermatogenesis (AZFc del). The molecular screening of these regions is routinely performed in the work-up of infertile patients with azoospermia or severe oligozoospermia as each one has different prognostic values, both in terms of clinical decision-making and appropriate genetic counselling as well as for understanding the etiology of spermatogenesis impairment. Different partial AZFc deletions were already described, although it is still controversial if these are truly a genetic risk factor for spermatogenesis impairment or a deletional variant without phenotypic consequences.
Here we present the molecular results obtained after AZF analysis of two infertile brothers (both diagnosed with oligoteratoastenozoospermia), and of their fertile father. Several multiplex-PCR assays were performed with distinct sets of STS markers, specific for the three AZF regions.
The molecular analysis revealed that all three men presented the same partial AZFb/c microdeletion, namely the absence of the sY1197, sY1291 and sY1192 STSs. This microdeletion probably results from the recombination of amplicons b1/b3, reducing the gene copy number of PRY, BPY, DAZ, and RBMY.
The b1/b3 deletion is rare and its influence on spermatogenesis is still not clear since it can be found in men with severe oligozoospermia or with normal sperm counts. Our result suggests that b1/b3 del is most likely a risk factor predisposing to spermatogenic failure, but is not sufficient alone. The different (in)fertile phenotypes associated with it, a fertile father opposed to his two infertile sons, can be possibly influenced by genetic background, environmental and epigenetic factors, contributing to different phenotypic expressions of individual/specific genomes
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