Competition between local potentials and attractive particle-particle interactions in superlattices

Naturally occuring or man-made systems displaying periodic spatial modulations of their properties on a nanoscale constitute superlattices. Such modulated structures are important both as prototypes of simple nanotechnological devices and as particular examples of emerging spatial inhomogeneity in interacting many-electron systems. Here we investigate the effect different types of modulation of the system parameters have on the ground-state energy and the charge-density distribution of the system. The superlattices are described by the inhomogeneous attractive Hubbard model, and the calculations are performed by density-functional and density-matrix renormalization group techniques. We find that modulations in local electric potentials are much more effective in shaping the system's properties than modulations in the attractive on-site interaction. This is the same conclusions we previously (Phys. Rev. B 71, 125130) obtained for repulsive interactions, suggesting that it is not an artifact of a specific state, but a general property of modulated structures.Comment: 8 pages, 2 figure

Opća jednadžba za neposrednu inverznu shemu podataka vertikalnog električnog sondiranja

A unified apparent resistivity equation is derived encompassing eight electrode configurations for Straightforward Inversion Scheme (SIS) on Vertical Electrical Sounding (VES) data. Suitable parameters are worked out to convert unified equation to a particular configuration viz. Wenner, Pole-Pole, Schlumberger, Pole-Dipole, Radial Dipole, Perpendicular Dipole, Parallel Dipole and Azimuthal Dipole. The derived equation is validated by forward computations of VES data for a 5-layer earth model that compares well with that of VES data obtained using existing individual equations for a particular configuration. SIS scheme is briefly described and a Schlumberger synthetic sounding data is generated using the unified equation over model riddled with equivalence /suppression and subsequently inverted using SIS to show the resolving power of the scheme via-a-vis low resistivity contrast between the layers. Two examples of field Schlumberger soundings from known lithology on a paleochannel in Mario Island in Northern Brazil are also included and the inverted continuous resistivity variation is presented to show the efficacy of the scheme.Izvedena je opća jednadžba za prividnu otpornost koja uključuje osam konfiguracija elektroda primjenjenih za neposrednu inverznu shemu (Straightforward Inversion Scheme (SIS)) podataka vertikalnog električnog sondiranja (VES). Nađeni su odgovarajući parametri koji omogućuju primjenu opće jednadžbe za određenu konfiguraciju (Wenner, pol-pol, Schlumberger, pol-dipol, radijalan dipol, okomit dipol, paralelni dipol i azimutalni dipol). Izračun za VES podatke za 5-slojni model podzemlja, dobro se slaže s podacima dobivenim upotrebom postojećih individualnih jednadžbi za određenu konfiguraciju, čime potvrđuje dobivenu jednadžbu. Opisana su dva primjera Schlumbergerovog sondiranja polja poznate litologije na paleo-kanalu na Mario otoku u sjevernom Brazilu i prikazana je varijacija invertiranog kontinuiranog otpora kako bi se pokazala efikasnost sheme

Genotypic variation for carotenoids content and chemometric model development for seed quality parameters in wheat

Published online: 19 August 2015Among the groups of naturally occurring pigments, carotenoids serve numerous purposes in plants, including antioxidant activity and protection of the photosynthetic apparatus from the excess of light. Alongside with essential mineral elements, these pigments are well known to have high impact on human health. Therefore, accumulation of carotenoids in wheat grain is an important trait in view to improving nutritional value of cereals. Wheat is one of the major staple foods in Portugal because of its agronomical adaptability and the usage of its flour into various traditional products. In the present investigation, the seeds of ninety-four Old Portuguese wheat cultivars grown over two years were analysed. Significant genetic variability for content of carotenoids was observed in the studied lines. Within the 47 bread wheat genotypes the Yellow Pigment Content (YPC) values varied from 2.7 - 5.8 μg/g and 3.0 - 8.0 μg/g for 2004/2005 and 2009/2010, respectively. On the other hand, during 2004/2005 and 2009/2010, the 47 durum wheat cultivars exhibited the YPC values from 1.1 - 8.0 μg/g and 3.4 - 8.3 μg/g, respectively. In addition, multivariate methods were also explored to assess the wheat grains quality, resorting to FTIR spectroscopy (Figure 1). Preliminary analyses of FTIR spectra clearly revealed differences among the distinct studied genotypes. Thus, in order to find spectroscopical patterns related to carotenoids accumulation and antioxidant activity, efforts are being made to develop a model that will allow the assessment of these parameters through FTIR, in the near-future

Fluorescence-Labeled Pyrenesulfonamide Response for Characterizing Polymeric Interfaces in Composite Materials

E-glass fibers were silanized using a 1% (v/v) aqueous solution of γ-aminopropyltriethoxysilane (APES). Pyrene—sulfonamide conjugates were formed by reaction of 1-pyrenesulfonyl chloride (PSC) in acetonitrile (AcN), with the amine groups immobilized on the glass fiber surface. These pyrene—sulfonamide conjugates were used as fluorescence probes, being a relatively simple analytical method to study the coating microstructure of polyorganosiloxane layer on glass fibers. The first aim of this work was to estimate possible interactions of the polyaminosiloxane coating with surrounding molecules of different solvents (solvent accessibility to the chromophore). For this study, the fluorescence response of pyrene—sulfonamide dye (PSA) was correlated with solvent polarity parameters. It was concluded that all the studied solvents were accessible to the chromophore, and they can gather in two groups, depending on their ability to swell the poliorganosiloxane layer. The second objective was to estimate the rigidity of the coating polymer from the temperature dependence of PSA emission. At about 180 K, a sudden change in the behavior of different photophysical parameters of PSA were observed. This phenomenon was interpreted as a density change in the polyaminosiloxane attached to the glass fibersThis research was supported by integrated actions Portugal–Spain, Reference HP1998-0014. J. Baselga, A. Aznar, and J. González-Benito wish to acknowledge the European Commission for support under the Brite-EuRam program (BE97-4472)

Overweight and Class I Obesity Are Associated with Lower 10-Year Risk of Mortality in Brazilian Older Adults: The Bambuí Cohort Study of Ageing

Background: Prospective studies mostly with European and North-American populations have shown inconsistent results r

C-Reactive Protein and B-Type Natriuretic Peptide Yield Either a Non-Significant or a Modest Incremental Value to Traditional Risk Factors in Predicting Long-Term Overall Mortality in Older Adults

Background:New biomarkers may aid in preventive and end-of-life decisions in older adults if they enhance the prognostic ability of traditional risk factors. We investigated whether C-reactive protein (CRP) and/or B-type natriuretic peptide (BNP) improve the ability to predict overall mortality among the elderly of the Bambuí, Brazil Study of Aging when added to traditional risk factors.Methods:From 1997 to 2007, 1,470 community-dwelling individuals (≥60 years) were followed-up. Death was ascertained by continuous verification of death certificates. We calculated hazard ratios per 1 standard deviation change (HR) of death for traditional risk factors only (old model), and traditional risk factors plus CRP and/or BNP (new models) and assessed calibration of the models. Subsequently, we compared c-statistic of each of the new models to the old one, and calculated integrated discriminative improvement (IDI) and net reclassification improvement (NRI).Results:544 (37.0%) participants died in a mean follow-up time of 9.0 years. CRP (HR 1.28, 95% CI 1.17-1.40), BNP (HR 1.31 95% CI 1.19-1.45), and CRP plus BNP (HR 1.26, 95% CI 1.15-1.38, and HR 1.29, 95% CI 1.16-1.42, respectively) were independent determinants of mortality. All models were well-calibrated. Discrimination was similar among the old (c-statistic 0.78 [0.78-0.81]) and new models (p=0.43 for CRP; p=0.57 for BNP; and p=0.31 for CRP plus BNP). Compared to the old model, CRP, BNP, and CRP plus BNP models led to an IDI of 0.009 (p<0.001), -0.005 (p<0.001) and -0.003 (p=0.84), and a NRI of 0.04 (p=0.24), 0.07 (p=0.08) and 0.06 (p=0.10), respectively.Conclusions:Despite being independent predictors of long-term risk of death, compared to traditional risk factors CRP and/or BNP led to either a modest or non-significant improvement in the ability of predicting all-cause mortality in older adults

Potential alternative feed sources for ruminant feeding from the biodiesel production chain by-products

This study aimed to evaluate the chemical composition, fractionation of nitrogen compounds and carbohydrates, digestibility parameters, gas production kinetics and ruminal fermentation of fruit seed cakes. The experiment was conducted in a completely randomized design with three fruit seed cakes (treatments) and four replications. The cakes were made of seeds of custard apple (Annona squamosa), soursop (Annona muricata) and passion fruit (Passiflora edulis), which were collected in a biodiesel plant. The passion fruit seed cake presented the highest content of dry matter, neutral detergent fibre crude protein (NDFcp), acid detergent fibre (ADF), lignin and total carbohydrates (P&lt;0.05). The custard apple seed cake presented high proportions of crude protein, condensed tannins and digestible energy (P&lt;0.05). The soursop seed cake presented higher values for ether extract and total digestible nutrients (P&lt;0.05). For potential degradability, the authors detected a difference between the custard apple, soursop and passion fruit seed cakes. The total volume of gases was higher for custard apple and soursop seed cakes. Custard apple seed cake presented higher proportions of in vitro degradation parameters (P&lt;0.05). Thus this cake could provide greater nutrient levels when supplied in ruminant diets, followed by soursop seed cake and passion fruit seed cake. Keywords: alternative food, by-products, ruminant feeding, seed cake, semi-ari

O sucesso de três anos do serviço IBGEPPP

Até o início de 2009, os pro ssionais que fazem uso das técnicas de posicionamento por satélites no desenvolvimento de suas atividades necessitavam de um programa de processamento de observações GPS gratuito, que calculasse de forma precisa as coordenadas dos levantamentos realizados. Em abril desse mesmo ano, o IBGE através da Coordenação de Geodésia, disponibilizou o serviço online IBGE-PPP, atendendo essa demanda e se tornando o primeiro país da América Latina a oferecer esse serviço gratuitamente. Em três anos de funcionamento, o IBGE-PPP já atendeu mais de 9.500 usuários, processando 127.352 arquivos de observações GPS. Este trabalho apresenta as principais características do serviço, além de fazer uma avaliação dos processamentos realizados pelos usuários, a precisão obtida nos processamentos,bem como as futuras implementações visando melhores resultados

Estudo Qualitativo sobre a "Proposta de Ferramenta de Avaliação Qualitativa de Ementas destinadas a Idosos"- Qual a perceção e contributos dos nutricionistas para uma proposta de atualização?

As contínuas alterações demográficas colocam-nos perante uma população cada vez mais envelhecida e com necessidades crescentes de cuidados alimentares, tanto numa ótica de cuidados de saúde, como de fornecimento de refeições, necessidade frequentemente suprida por serviços de alimentação coletiva. A qualidade nutricional e alimentar da oferta assume-se como um determinante major na saúde e satisfação dos idosos, sendo o plano de ementas uma das mais importantes ferramentas de gestão na área. Para que seja promovida uma oferta alimentar adequada, é essencial a existência de orientações que a balizem e que sejam alvo de atualização e melhoria contínua. A envolvência de nutricionistas no processo possibilita a revisão por pares e uma maior adaptação à realidade, permitindo obter ferramentas que auxiliem na tomada de decisão e na sustentação do trabalho desenvolvido. O presente estudo tem como objetivo explorar a perceção e os contributos de nutricionistas sobre o documento “Proposta de Ferramenta de Avaliação Qualitativa de Ementas destinadas a Idosos”, visando uma proposta de atualização. Foi adotada uma metodologia qualitativa através da realização de grupos focais a partir de uma amostra por conveniência, constituída por 38 nutricionistas. Os resultados sugerem que, apesar de ser considerada útil, a ferramenta carece de atualização para uma maior adaptação à faixa etária e à realidade prática. Da análise de critérios específicos, os participantes identificam vários de difícil cumprimento (ex. oferta equitativa de métodos de confeção, não repetição de fruta, oferta de oleaginosas, refeições de ovo e de massa ou arroz integral), partilhando os motivos para tal. Sugerem ainda a necessidade de inclusão de critérios para alimentação de textura modificada e refletem acerca de possíveis melhorias na própria dinâmica de aplicação da ferramenta. Em suma, a discussão promovida deixa importantes contributos para uma possível atualização da ferramenta, numa ótica de maior ajuste à faixa etária e de inclusão de critérios sobre tópicos emergentes.Continuous demographic changes confront us with an increasingly elderly population with growing needs for nutritional care, both from a health care perspective and from meals’ provision, which is often supplied by food services. The nutritional and food quality is a major determinant of the seniors’ health and satisfaction, and the menu is one of the most important management tools. To promote an adequate food offer, it is essential to have guidelines, that must be updated and continuously improved. The involvement of nutritionists in this process enables peer review and greater adaptation to reality, allowing to obtain tools that help in the decision-making process and sustain the developed work. This work aims to explore the perceptions and contributions of nutritionists on the document “Proposta de Ferramenta de Avaliação Qualitativa de Ementas destinadas a Idosos”, with a view to an update proposal. A qualitative methodology was adopted by conducting focus groups with a convenience sample of 38 nutritionists. Results suggest that, although the tool is considered useful, it needs to be updated to better adapt to the targeted age group and to the practical context. From the analysis of specific criteria, participants identify difficulties to comply with some of them (e.g. equitable offering of cooking methods, non-repetition of fruit, offering of oilseeds, egg based meals and whole wheat pasta or wholegrain rice), sharing the reasons why. They also suggest the need to include criteria for texture modified foods and they reflect on possible improvements in the tool application. In conclusion, the discussion promoted breeds important contributions for a possible update of the tool, in a perspective of greater adjustment to the age group it is destined to and inclusion of criteria on emerging topics.info:eu-repo/semantics/publishedVersio