Importance of non-affine viscoelastic response in disordered fibre networks

Disordered fibre networks are ubiquitous in nature and have a wide range of industrial applications as novel biomaterials. Predicting their viscoelastic response is straightforward for affine deformations that are uniform over all length scales, but when affinity fails, as has been observed experimentally, modelling becomes challenging. Here we present a numerical methodology, related to an existing framework for amorphous packings, to predict the steady-state viscoelastic spectra and degree of affinity for disordered fibre networks driven at arbitrary frequencies. Applying this method to a peptide gel model reveals a monotonic increase of the shear modulus as the soft, non-affine normal modes are successively suppressed as the driving frequency increases. In addition to being dominated by fibril bending, these low frequency network modes are also shown to be delocalised. The presented methodology provides insights into the importance of non-affinity in the viscoelastic response of peptide gels, and is easily extendible to all types of fibre networks

Estimating the value of risk reduction for pedestrians in the road environment: An exploratory analysis

In recent years there has been a re-focus on the valuation of a statistical life from the ex post or human capital method to an ex ante willingness to pay (WTP) approach. This is in part a recognition that we need to focus on establishing the amount, ex ante, that individuals are willing to pay to reduce the risk of exposure to circumstances that might lead to death or degree of injury in the road environment. This study sets out a framework in which to identify the degree of preference heterogeneity in WTP of pedestrians to avoid being killed or injured. A stated choice experiment approach is developed. The empirical setting is a choice of walking route for a particular trip that a sample of pedestrians periodically undertakes in Australia. Mixed logit models are estimated to obtain the marginal (dis)utilities associated with each influence on the choice amongst the attribute packages offered in the stated choice scenarios. These conditional estimates are used to obtain the WTP distributions for fatality and classes of injury avoidance, which are then aggregated to obtain estimates for pedestrians of the value of risk reduction (VRR)

The distance to the Fornax Dwarf Spheroidal Galaxy

A large multicolour, wide-field photometric database of the Fornax dwarf spheroidal galaxy has been analysed using three different methods to provide revised distance estimates based on stellar populations in different age intervals. The distance to Fornax was obtained from the Tip of the Red Giant Branch measured by a new method, and using the luminosity of Horizontal Branch stars and Red Clump stars correc ted for stellar population effects. Assuming a reddening $E(B-V)=0.02$, the following distance moduli were derived: $(m-M)_0=20.71 \pm 0.07$ based on the Tip of the Red Giant Branch, $(m-M)_0=20.72 \pm 0.06$ from the level of the Horizontal Branch, and $(m-M)_0=20.73 \pm 0.09$ using the Red Clump method. The weighted mean distance modulus to Fornax is $(m-M)_0=20.72 \pm 0.04$. All these measurements agree within the errors, and are fully consistent with previous determinations and with the distance measurements obtained in a companion paper from near-infrared colour-magnitude diagrams.Comment: Accepted for publication on Monthly Notices of the Royal Astronomical Societ

Percolação de poluentes em solos após aplicação de resíduos de fábrica de papel reciclado.

O estudo dos efeitos da aplicação de resíduos de fábrica de papel reciclado na água percolada pelo solo foi o objetivo deste trabalho. A aplicação de resíduos de fábricas de papel em solos tem sido crescente e despertado a atenção pela possibilidade de contaminação do meio ambiente, principalmente pela poluição das águas. Com o uso de resíduo de fábrica de papel reciclado, foi realizado um ensaio em casa de vegetação da Embrapa, em Colombo (PR). Foram montados tubos de PVC com mistura de resíduo e dois tipos de solo, Neossolo Regolítico Distrófico húmico e Cambissolo Húmico Distrófico típico. O experimento foi realizado em blocos inteiramente casualizados, com três repetições, com dosagens crescentes (0, 10, 20, 40 e 80 t.ha-1). A duração foi de 140 dias, com a coleta da água de percolação dos vasos. Os resultados foram comparados aos limites da Resolução CONAMA n°. 357/05. Os teores de alumínio, ferro e manganês excederam os limites da legislação. Não excederam os limites o chumbo, o cromo, os fenóis, o nitrogênio amoniacal, os nitratos, os nitritos, os ortofosfatos, o sódio e os surfactantes

On a stationary spinning string spacetime

The properties of a stationary massless string endowed with intrinsic spin are discussed. The spacetime is Minkowskian geometrically but the topology is nontrivial due to the horizon located on the surface $r=0$, similar with Rindler's case. For $r$ less than the Planck length $b$, $g_{\phi\phi}$ has the same sign as $g_{tt}$ and closed timelike curves are possible. We assume an elementary particles' spin originates in the frame dragging effect produced by the rotation of the source. The Sagnac time delay is calculated and proves to be constant.Comment: revised version of hep-th/0602014 v1, 7 pages, title changed, sec.5 removed, talk given at "Recent Developments in Gravity" (NEB XII), Nafplio, Greece, 29 June 200

Inovação em um Sistema de Informação para Gestão de Acidentes de Trânsito na Perspectiva de Produto e Processo

Neste trabalho apresenta-se um Sistema de Informações Geográfico, SIG, para apoio a tomada de decisão a respeito de acidentes e acidentados de trânsito em âmbito municipal e são discutidos aspectos inovadores, enfatizando sua concepção, e as tecnologias utilizadas em sua implementação. São feitos comentários sobre a versão anterior do SIG, monolítica, e a proposta para a versão orientada a microserviços. São apontados motivações e desafios relativos ao uso de paradigma de programação funcional e microserviços. Destaca-se que as principais inovações dizem respeito aos objetivos estratégicos para o negócio e as características arquiteturais para seu desenvolvimento

Alterações químicas do solo após aplicação de biossólidos de estação de tratamento de efluentes de fábrica de papel reciclado.

O estudo dos efeitos da aplicação de resíduos de fábrica de papel reciclado em solos florestais nas propriedades químicas de dois tipos de solo foi o objetivo principal deste trabalho. A utilização de resíduos, mesmo com baixa quantidade de nutrientes, é defendida por vários autores, principalmente visando conciliar as necessidades nutricionais com os processos de ciclagem de nutrientes para se manter a produtividade dos plantios florestais. Utilizando-se de resíduos de fábrica de papel reciclado, foi realizado experimento em casa de vegetação da EMBRAPA, em Colombo (PR). Foram montados, em tubos de PVC, misturas de resíduos em dois tipos de solo, Neossolo Regolítico distrófico húmico e Cambissolo húmico distrófico típico. O delineamento experimental foi realizado em blocos inteiramente casualizados, com três repetições, com dosagens crescentes (0, 10, 20, 40 e 80 t.ha-1). No final do experimento, depois de 147 dias de duração, foi realizada a análise de três camadas de solo: 0?10 cm, 10?20 cm e 20?30 cm. A aplicação dos resíduos de papel reciclado influenciou as propriedades químicas do solo, como o aumento no pH, a diminuição no alumínio trocável, a diminuição da acidez potencial, o aumento nos níveis de cálcio e magnésio, o aumento nas camadas iniciais para o fósforo e o aumento na saturação de bases, sem alteração do conteúdo de sódio e matéria orgânica do solo.O sobrenome do último autor está grafado erroneamente: Lavorani

Star Formation History and Chemical Evolution of the Sextans Dwarf Spheroidal Galaxy

We present the star formation history and chemical evolution of the Sextans dSph dwarf galaxy as a function of galactocentric distance. We derive these from the $VI$ photometry of stars in the $42' \times 28'$ field using the SMART model developed by Yuk & Lee (2007, ApJ, 668, 876) and adopting a closed-box model for chemical evolution. For the adopted age of Sextans 15 Gyr, we find that $>$84% of the stars formed prior to 11 Gyr ago, significant star formation extends from 15 to 11 Gyr ago ($\sim$ 65% of the stars formed 13 to 15 Gyr ago while $\sim$ 25% formed 11 to 13 Gyr ago), detectable star formation continued to at least 8 Gyr ago, the star formation history is more extended in the central regions than the outskirts, and the difference in star formation rates between the central and outer regions is most marked 11 to 13 Gyr ago. Whether blue straggler stars are interpreted as intermediate age main sequence stars affects conclusions regarding the star formation history for times 4 to 8 Gyr ago, but this is at most only a trace population. We find that the metallicity of the stars increased rapidly up to [Fe/H]=--1.6 in the central region and to [Fe/H]=--1.8 in the outer region within the first Gyr, and has varied slowly since then. The abundance ratios of several elements derived in this study are in good agreement with the observational data based on the high resolution spectroscopy in the literature. We conclude that the primary driver for the radial gradient of the stellar population in this galaxy is the star formation history, which self-consistently drives the chemical enrichment history.Comment: 36 pages, 14 figures, To appear in the ApJ, 200

Usfmat: an extension project that links mathematics and computer science to contribute to social inclusion

One of the roles of universities, besides teaching and research, is to contribute to society more directly, through extension projects. One way of reaching this goal is to contribute to the development of municipalities where development is still small. In this paper, we developed a project that employed the concepts of mathematics and computer science, in a coordinated way, to contribute to the target audience with improved incomes, their chances of admission to the IES and also for their development as citizens. The public focus of this study were students of the Catanduvas - PR, attending high school and who were close to entering the employment market or IES. It was verified that there was a contribution to the students who participated in the project, from the use of knowledge in their day to day, but also for knowledge in preparation for college entrance examination. There was also progress by ministering school students, knowing that this work enabled them to a first contact with teaching and an improvement in their training as undergraduates. The project's contribution to the development of the municipality, however, is a slow process that requires monitoring over several years of implementation, which preludes at this time, an immediate evaluation of project impact on local community.</p