23,045 research outputs found
Conformal and gauge invariant spin-2 field equations
Using an approach based on the Casimir operators of the de Sitter group, the
conformal invariant equations for a fundamental spin-2 field are obtained, and
their consistency discussed. It is shown that, only when the spin-2 field is
interpreted as a 1-form assuming values in the Lie algebra of the translation
group, rather than a symmetric second-rank tensor, the field equation is both
conformal and gauge invariant.Comment: 12 pages, no figures; accepted for publication in Gravitation &
Cosmolog
Chemical analysis of giant stars in the young open cluster NGC 3114
Context: Open clusters are very useful targets for examining possible trends
in galactocentric distance and age, especially when young and old open clusters
are compared. Aims: We carried out a detailed spectroscopic analysis to derive
the chemical composition of seven red giants in the young open cluster NGC
3114. Abundances of C, N, O, Li, Na, Mg, Al, Ca, Si, Ti, Ni, Cr, Y, Zr, La, Ce,
and Nd were obtained, as well as the carbon isotopic ratio. Methods: The
atmospheric parameters of the studied stars and their chemical abundances were
determined using high-resolution optical spectroscopy. We employed the
local-thermodynamic-equilibrium model atmospheres of Kurucz and the spectral
analysis code MOOG. The abundances of the light elements were derived using the
spectral synthesis technique. Results: We found that NGC 3114 has a mean
metallicity of [Fe/H] = -0.01+/-0.03. The isochrone fit yielded a turn-off mass
of 4.2 Msun. The [N/C] ratio is in good agreement with the models predicted by
first dredge-up. We found that two stars, HD 87479 and HD 304864, have high
rotational velocities of 15.0 km/s and 11.0 km/s; HD 87526 is a halo star and
is not a member of NGC 3114. Conclusions: The carbon and nitrogen abundance in
NGC 3114 agree with the field and cluster giants. The oxygen abundance in NGC
3114 is lower compared to the field giants. The [O/Fe] ratio is similar to the
giants in young clusters. We detected sodium enrichment in the analyzed cluster
giants. As far as the other elements are concerned, their [X/Fe] ratios follow
the same trend seen in giants with the same metallicity.Comment: 17 pages, 9 figures, 10 tables; accepted for publication in A&
Efeito de diferentes fontes e níveis de nitrogênio na produção de cana-de-açucar.
A eficiência da uréia e sulfato de amônio como fontes de nitrônio para as plantas está condicionado às condições climáticas, características do solo e técnicas de aplicação
The relationship between depression and violence risk predictors on Elderly
The purpose of this study was to understand the correlation between the elderly with depressive symptomatology and the predictors of the risk of violence against them. The method used was a quantitative approach using the Statistical Package program for Social Sciences. There was a participation of 237 elderly people aged 65-96 years, of the project “Aging in Safety in Alentejo - Understanding to Act”, at the University of Évora. The Geriatric Depression Scale and the Predictors of Risk of Violence (an adaptation of the Elder Abuse and Neglect-Risk Assessment Tool and Vulnerability to Abuse Screening Scale) were applied. About the results, 50 elderly (21.1%) had mild depressive symptomatology, and 14 (5.9%) had severe depressive symptomatology. Of the 64 elderly individuals who presented depressive symptomatology 55 were female. In the relationship between the severity of depressive symptomatology and predictors of risk of violence, significant results were found in three dimensions: current supports and relationships, family context and cognitive / emotional difficulties. The main conclusion of the study is that factors like no social support networks, complex family context and cognitive and emotional changes, contribute to greater physical and mental vulnerability of the elderly, resulting in cases of anxiety and stress, which present a depressive symptomatology and the risk of violence
The INFAUCI study
Funding Information: Financial support: this work was supported by an unrestricted grant from GIS (Grupo de Infecção e Sepsis, Hospital de São João, Porto, Portugal). Publisher Copyright: © 2014 European Society of Clinical Microbiology and Infectious Diseases2012 December 2014 10.1111/1469-0691.12738 Original Article INFECTIOUS DISEASES Original Articles © 2014 The Authors Clinical Microbiology and Infection © 2014 European Society of Clinical Microbiology and Infectious Diseases.A prospective, cohort, clinical, observational study was performed in 14 Intensive Care Units (ICUs) to evaluate the contemporary epidemiology, morbi-mortality and determinants of outcome of the population with an infection on admission. All 3766 patients admitted during a consecutive 12-month period were screened. Their median age was 63 [26-83], 61.1% were male and 69.8% had significant comorbidities. On admission to the ICU 1652 patients (43.9%) had an infection, which was community acquired in 68.2% (one-fifth with healthcare-associated criteria) and ward-acquired in the others. Roughly half presented to the ICU with septic shock. As much as 488 patients with community-acquired infections were deemed stable enough to be first admitted to the ward, but had similar mortality to unstable patients directly admitted to the ICU (35.9% vs. 35.1%, p 0.78). Only 48.3% of this infected population had microbiological documentation and almost one-quarter received inappropriate initial antibiotic therapy. This, along with comorbidities, was a main determinant of mortality. Overall, infected patients on admission had higher mortality both in the ICU (28.0% vs. 19.9%, p <0.001) and in the hospital (38.2% vs. 27.5%, p <0.001) and even after being discharged to the ward (14.2% vs. 9.6%, p <0.001). Also, patients not infected on admission who acquired an infection in the ICU, had an increased risk of dying in the hospital (odds ratio 1.41 [1.12-1.83]). Consequently, infection, regardless of its place of acquisition, was associated with increased mortality. Improving the process of care, especially first-line antibiotic appropriateness, and preventing ICU-acquired infections, may lead to better outcomes.publishersversionpublishe
Density functional investigations of defect induced mid-gap states in graphane
We have carried out ab initio electronic structure calculations on graphane
(hydrogenated graphene) with single and double vacancy defects. Our analysis of
the density of states reveal that such vacancies induce the mid gap states and
modify the band gap. The induced states are due to the unpaired electrons on
carbon atoms. Interestingly the placement and the number of such states is
found to be sensitive to the distance between the vacancies. Furthermore we
also found that in most of the cases the vacancies induce a local magnetic
moment.Comment: 15 page
Behaviour of biofilms formed by Pseudomonas fluorescens under different flow regimes when exposed to surfactants : role of the biofilm mechanical stability
The effectiveness of cetyltrimethyl ammonium bromide (CTAB) and sodium dodecyl
sulfate (SDS) to control biofilms formed by Pseudomonas fluorescens on stainless steel
slides under laminar and turbulent conditions, using a flow cell reactor, is compared in
this study. The antimicrobial action of the surfactants was evaluated in terms of the
activity of the biofilm, the biofilm mass that remained on the surface after treatment and
the biofilm morphological characteristics. The mechanical stability of the biofilm was
also assessed using a bioreactor rotating device. For comparative purpose, the action of
the surfactants against bacterial suspended cultures was also evaluated. The interference
of proteins (bovine serum albumin-BSA), acting as soil, on the action of the surfactants
was also investigated.
Turbulent P. fluorescens biofilm seemed to be more difficult to inactivate, by CTAB
treatment, than the laminar biofilm. However, the total inactivation of the cells within
the biofilms was not achieved for both types of biofilms. Concerning SDS, higher
concentrations promoted significant biofilm inactivation. Biofilms formed under
turbulent and laminar flow had analogous susceptibility to SDS application. Regarding
biofilm removal, both surfactants appeared to have poor effect, independently of the
flow regime under which biofilms were formed. It was also seen that, the structure of
biofilms was changed after the application of both surfactants. The mechanical stability
of the biofilm was differently conditioned depending on the surfactant used: CTAB
increased the biofilm removal regardless of the concentration tested; whereas, SDS, for
concentrations far from the critical micellar concentration promoted biofilm
strengthening, since the amount of biomass that remained attached to the surface, after
submission to the different shear stresses, increased with SDS application. As
expected, the toxic action of the surfactants was more pronounced in suspended
bacteria, than in biofilms. This toxic action was significantly reduced when BSA was
added to the suspended cultures, emphasizing that these surfactants react strongly with
proteins. From this study, it can be stated that chemical treatment is far from being a
tool that induces massive detachment of P. fluorescens biofilms and even the
synergistic chemical and mechanical treatment did not promoted total biofilm removal,
emphasizing the need of care in choosing the correct procedure for biofilm control and
the recalcitrant properties of biofilms
Aumento da sobrevivência de mudas de raiz nua de seringueira pela parafinagem e indução de raízes.
Um dos principais problemas observados na implantação de seringais do PROBOR na Região Amazônica, a partir de mudas plantadas de raiz nua foi o alto índice de mortalidade, em tomo de 50%, quando imediatamente após o plantio ocorrem veranicos ocasionais, com duração superior a uma semana, causando sérios prejuízos ao produtor, com aquisição de novas mudas, replantios além de ocorrerem desuniforrnidades de crescimento e atrasos na entrada em produção do seringal. Visando contornar esse problema, avaliou-se o efeito da decepagem cerce à placa do enxerto (lcm), seguida da parafinagem associada à indução de raizes com o uso do AIB (Ácido Indol Butírico) a 2.000 ppm, em tratamentos diferenciados, em mudas transplantadas para sacos de plástico e submetidas a apenas uma aguação por semana, obtendo-se urna antecipação na brotação da gema do enxerto e concomitante início da rizogênese aos 20 dias após o transplantio destas, o que se refletiu positivamente sobre as variáveis tamanho das brotações, comprimento dos lançamentos, altura de plantas e percentagem de tocos vivos aos 60 dias, em relação ao controle com decepagem alta (l5cm) pincelado apenas com tinta a óleo na superfície decepada. Resultados semelhantes foram obtidos também aos 20 dias, para tocos parafinados com o uso de alfa naftaleno acetato de sódio (ANA) em estudo complementar
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