Fitting isochrones to open cluster photometric data III. Estimating metallicities from UBV photometry

The metallicity is a critical parameter that affects the correct determination fundamental characteristics stellar cluster and has important implications in Galactic and Stellar evolution research. Fewer than 10 % of the 2174 currently catalog open clusters have their metallicity determined in the literature. In this work we present a method for estimating the metallicity of open clusters via non-subjective isochrone fitting using the cross-entropy global optimization algorithm applied to UBV photometric data. The free parameters distance, reddening, age, and metallicity simultaneously determined by the fitting method. The fitting procedure uses weights for the observational data based on the estimation of membership likelihood for each star, which considers the observational magnitude limit, the density profile of stars as a function of radius from the center of the cluster, and the density of stars in multi-dimensional magnitude space. We present results of [Fe/H] for nine well-studied open clusters based on 15 distinct UBV data sets. The [Fe/H] values obtained in the ten cases for which spectroscopic determinations were available in the literature agree, indicating that our method provides a good alternative to determining [Fe/H] by using an objective isochrone fitting. Our results show that the typical precision is about 0.1 dex

Pricing for scarcity

DINÂMIA, Junho de 2008.“Prémio Científico ISCTE-IUL 2012”In many areas where water is not abundant, water pricing schedules contain significant nonlinearities. Existing pricing literature establishes that efficient schedules will depend on demand and supply characteristics. However, most empirical studies show that actual pricing schemes have little to do with theoretical efficiency results. In particular, there are very few models recommending increasing blocks, whereas we present evidence that this type of tariff structure is abundantly used. Water managers often defend increasing blocks, both as a means to benefit smaller users and as a way to signal scarcity. Naturally, in the presence of water scarcity the true cost of water increases due to the emergence of a scarcity cost. In this paper, we incorporate the scarcity cost associated with insufficient water availability into the optimal tariff design in several different models. We show that when both demand and costs respond to climate factors, increasing marginal prices may come about as a combined result of scarcity and customer heterogeneity under specific conditions. We also investigate the effect that rising water scarcity in the long run can have on the steady-state amount of capital invested in water storage and supply infrastructures and obtain some results that are consistent with the static models.FC

Chaotic quantum ratchets and filters with cold atoms in optical lattices: properties of Floquet states

Recently, cesium atoms in optical lattices subjected to cycles of unequally-spaced pulses have been found to show interesting behavior: they represent the first experimental demonstration of a Hamiltonian ratchet mechanism, and they show strong variability of the Dynamical Localization lengths as a function of initial momentum. The behavior differs qualitatively from corresponding atomic systems pulsed with equal periods, which are a textbook implementation of a well-studied quantum chaos paradigm, the quantum delta-kicked particle (delta-QKP). We investigate here the properties of the corresponding eigenstates (Floquet states) in the parameter regime of the new experiments and compare them with those of the eigenstates of the delta-QKP at similar kicking strengths. We show that, with the properties of the Floquet states, we can shed light on the form of the observed ratchet current as well as variations in the Dynamical Localization length.Comment: 9 pages, 9 figure

Avaliação do crescimento de mudas de Eucalyptus benthamii após o uso de Bacsol®.

Em função do crescente plantio de Eucalyptus benthamii em regiões frias, existe grande demanda por mudas, contudo esta espécie apresenta dificuldades no seu desenvolvimento. Para contornar este tipo de problema, alguns produtos biotecnológicos têm sido usados para estimular o crescimento de mudas. Assim, o objetivo deste trabalho foi avaliar o uso do produto biotecnológico Bacsol® para aumentar o crescimento de mudas de E. benthamii. Este produto é um formulado constituído em sua maioria por esporos bacterianos, que atua como agente estimulador do crescimento de plantas, permitindo que cresçam em menor tempo e com uma melhor qualidade. Para este experimento utilizou-se um delineamento de blocos ao acaso, contendo cinco tratamentos e cada tratamento com 240 mudas, sendo uma testemunha e as doses crescentes do produto (0,5 g; 1 g; 1,5 g; 2 g/muda), em três blocos. Os resultados mostraram que houve aumento significativo da altura das mudas de acordo com o aumento da dosagem do produto (p < 0,001).Resumo expandido

Uso do produto Bacsol® no crescimento de mudas de Eucalyptus benthamii.

Resumo

Ocorrência de Pisolithus tinctorius em plantios jovens de Eucalyptus benthamii.

Editores técnicos: Marcílio José Thomazini, Elenice Fritzsons, Patrícia Raquel Silva, Guilherme Schnell e Schuhli, Denise Jeton Cardoso, Luziane Franciscon. EVINCI. Resumos

Buckling analysis of laminated anisotropic kirchhoffs plates via the boundary element method

A new fundamental solution for laminated anisotropic Kirchhoff’s plates with out-of-plane and in-plane compressive loads is derived here. The multicompressed solution for both isotropic and anisotropic cases is obtained via the Radon Transform. Some fundamental kernels of the integral equations are described in detail. BEM results of displacements and critical buckling loads of several plates with different boundary conditions and geometries are presented. Comparisons with available analytical solutions and some published numerical results confirm the reliability and accuracy of the proposed formulation151

Fractures in Children and Adolescents with Spina Bifida: The Experience of a Portuguese Tertiary-Care Hospital

AIM: The morbidity associated with osteoporosis and fractures in children and adolescents with spina bifida highlights the importance of osteoporosis prevention and treatment in these patients. The aim of this study was to examine the occurrence and pattern of bone fractures in paediatric patients with spina bifida. METHOD: We reviewed the data of all paediatric patients with spina bifida who were treated in our centre between 1999 and 2008. RESULTS: One hundred and thirteen patients were included in the study (63 females, 50 males; mean age 10y 8mo, SD 4y 10mo, range 6mo-18y). The motor levels were thoracic in six, upper lumbar in 22, lower lumbar in 42, and sacral in 43 patients. Of the 113 patients, 58 (51.3%) had shunted hydrocephalus. Thirty-six (31.8%) were non-ambulatory (wheelchair-dependent [unable to self-propel wheelchair] n=3, wheelchair-independent [able to self-propel wheelchair] n=33), 13 were partial ambulators, 61 were full ambulators, and three were below the age of walking. Forty-five fractures were reported in 25 patients. The distal femur was the most common fracture site. Statistical analyses showed that patients with higher levels of involvement and in wheelchairs had a significantly increased risk of having a [corrected] fracture (p<0.001). Spontaneous fractures were the principal mechanism of injury, and an association was identified between fracture mechanism, type of ambulation, and lesion level: the fractures of patients with higher levels of motor functioning and those in wheelchairs were mainly pathological (p=0.01). We identified an association between risk of a second fracture, higher motor level lesion, and non-ambulation. There was an increased risk of having a second fracture after a previous spontaneous fracture (p=0.004). INTERPRETATION: Data in this study indicate a high prevalence of fractures in patients with spina bifida