Origin of the heavy elements in HD 140283. Measurement of europium abundance

HD 140283 is a nearby (V=7.7) subgiant metal-poor star, extensively analysed in the literature. Although many spectra have been obtained for this star, none showed a signal-to-noise (S/N) ratio high enough to enable a very accurate derivation of abundances from weak lines. The detection of europium proves that the neutron-capture elements in this star originate in the r-process, and not in the s-process, as recently claimed in the literature. Based on the OSMARCS 1D LTE atmospheric model and with a consistent approach based on the spectrum synthesis code Turbospectrum, we measured the europium lines at 4129 {\AA} and 4205 {\AA}, taking into account the hyperfine structure of the transitions. The spectrum, obtained with a long exposure time of seven hours at the Canada-France-Hawaii Telescope (CFHT), has a resolving power of 81000 and a S/N ratio of 800 at 4100 {\AA}. We were able to determine the abundance A(Eu)=-2.35 dex, compatible with the value predicted for the europium from the r-process. The abundance ratio [Eu/Ba]=+0.58 dex agrees with the trend observed in metal-poor stars and is also compatible with a strong r-process contribution to the origin of the neutron-capture elements in HD 140283.Comment: 10 pages, 7 figures. To be published in A\&

Parenting Stress in Immigrant Families of Children With an Autism Spectrum Disorder: A Comparison With Families From the Host Culture

Immigrant families of children with autism spectrum disorders (ASD) face significant challenges in accessing and using rehabilitation services appropriate for their child’s disorder. Compared to families native to their host country, the stress experienced by these families in relation to their child’s condition may be magnified by their immigrant status. This study compared self-reported parenting stress levels among 24 mothers and 17 fathers who had immigrated to Canada to income-matched, Canadian-born parents. Overall, Canadian-born parents tended to report higher stress levels than immigrant parents, but this may be primarily due to the high stress levels among Canadian-born fathers relative to immigrant fathers and mothers from both types of families. These findings highlight the necessity of using supplemental and specialized stress measures when focusing on immigrant families, for whom stress associated with the immigration process may compound or manifest separately from parenting stress. Cultural influences on the perception of ASD (its causes, treatment, and prognosis), children’s place in the family, and parents’ roles in childrearing may also impact stress

Statistical fluctuations of the parametric derivative of the transmission and reflection coefficients in absorbing chaotic cavities

Motivated by recent theoretical and experimental works, we study the statistical fluctuations of the parametric derivative of the transmission T and reflection R coefficients in ballistic chaotic cavities in the presence of absorption. Analytical results for the variance of the parametric derivative of T and R, with and without time-reversal symmetry, are obtained for both asymmetric and left-right symmetric cavities. These results are valid for arbitrary number of channels, in completely agreement with the one channel case in the absence of absorption studied in the literature.Comment: Modified version as accepted in PR

Statistical wave scattering through classically chaotic cavities in the presence of surface absorption

We propose a model to describe the statistical properties of wave scattering through a classically chaotic cavity in the presence of surface absorption. Experimentally, surface absorption could be realized by attaching an "absorbing patch" to the inner wall of the cavity. In our model, the cavity is connected to the outside by a waveguide with N open modes (or channels), while an experimental patch is simulated by an "absorbing mirror" attached to the inside wall of the cavity; the mirror, consisting of a waveguide that supports Na channels, with absorption inside and a perfectly reflecting wall at its end, is described by a subunitary scattering matrix Sa. The number of channels Na, as a measure of the geometric cross section of the mirror, and the lack of unitarity of Sa as a measure of absorption, are under our control: these parameters have an important physical significance for real experiments. The absorption strength in the cavity is quantified by the trace of the lack of unitarity. The statistical distribution of the resulting S matrix for N=1 open channel and only one absorbing channel, Na =1, is solved analytically for the orthogonal and unitary universality classes, and the results are compared with those arising from numerical simulations. The relation with other models existing in the literature, in some of which absorption has a volumetric character, is also studied.Comment: 6 pages, 3 figures, submitted to Phys. Rev.

Task planning and control synthesis for robotic manipulation in space applications

Space-based robotic systems for diagnosis, repair and assembly of systems will require new techniques of planning and manipulation to accomplish these complex tasks. Results of work in assembly task representation, discrete task planning, and control synthesis which provide a design environment for flexible assembly systems in manufacturing applications, and which extend to planning of manipulatiuon operations in unstructured environments are summarized. Assembly planning is carried out using the AND/OR graph representation which encompasses all possible partial orders of operations and may be used to plan assembly sequences. Discrete task planning uses the configuration map which facilitates search over a space of discrete operations parameters in sequential operations in order to achieve required goals in the space of bounded configuration sets

High-resolution abundance analysis of HD 140283

HD 140283 is a reference subgiant that is metal poor and confirmed to be a very old star. The abundances of this type of old star can constrain the nature and nucleosynthesis processes that occurred in its (even older) progenitors. The present study may shed light on nucleosynthesis processes yielding heavy elements early in the Galaxy. A detailed abundance analysis of a high-quality spectrum is carried out, with the intent of providing a reference on stellar lines and abundances of a very old, metal-poor subgiant. We aim to derive abundances from most available and measurable spectral lines. The analysis is carried out using high-resolution (R = 81 000) and high signal-to-noise ratio (800 < S/N/pixel < 3400) spectrum, in the wavelength range 3700 - 10475, obtained with a seven-hour exposure time, using the ESPaDOnS at the CFHT. The calculations in LTE were performed with the OSMARCS 1D atmospheric model and the spectrum synthesis code Turbospectrum, while the analysis in NLTE is based on the MULTI code. We present LTE abundances for 26 elements, and NLTE calculations for the species C I, O I, Na I, Mg I, Al I, K I, Ca I, Sr II, and Ba II lines. The abundance analysis provided an extensive line list suitable for metal-poor subgiant stars. The results for Li, CNO, alpha-, and iron peak elements are in good agreement with literature. The newly NLTE Ba abundance, along with a NLTE Eu correction and a 3D Ba correction from literature, leads to [Eu/Ba] = +0.59 +/- 0.18. This result confirms a dominant r-process contribution, possibly together with a very small contribution from the main s-process, to the neutron-capture elements in HD 140283. Overabundances of the lighter heavy elements and the high abundances derived for Ba, La, and Ce favour the operation of the weak r-process in HD 140283.Comment: 34 pages, 27 figure

Análise de Envoltória de Dados para alocação de recursos: uma proposta de algoritmo sequencial.

Este trabalho apresenta um modelo sequencial de atribuição de recursos em modelos DEA, inspirado no modelo de votação de Hondt, considerando-se que o excesso de recursos a ser distribuído tem soma constante. Caso fosse de interesse realocal os recursos já existentes, mantendo-se constante o total dos recursos (soma dos recursos constante) poderia ser usado o modelo DEA com Ganhos de Soma Zero - GSZ-DEA, orientado a inputs. O algoritmo sequencial de alocação de recursos em DEA proposto neste artigo é aplicado à distribuição de vagas docentes aos departamentos de ensino do Centro Tecnológico da UFF. O modelo considera o número de professores de cada departamento, o envolvimento com atividades de ensino e pesquisa e a existência de projetos de expansão aprovados

UNCERTAINTY IN STATIC PRESSURE CORRECTION IN A SUBSONIC WIND TUNNEL

The static pressure p on the subsonic Wind Tunnel of the Aerodynamic Testing Laboratory of the Institute of Aeronautics and Space IAE, Aerospace Technical Center CTA, is measured using an absolute pressure sensor, located on the upper test section wall. This measurement is not taken at the same location as the one where the model is mounted during the actual wind tunnel test. This fact raises the need for a correction during data reduction. The identification and evaluation of the associated error source is important because the static pressure is an input quantity for the calculation of the total pressure pt, Mach number M and density ρ during the test. The present paper is concerned with the determination of the relationship between the static pressure measured on the tunnels upper wall and that at the model location, and with the analysis of the uncertainty propagation for the measured flow parameters

Controle de doenças de plantas usando isolados brasileiros de Trichoderma harzianum.

The objective of this research is to characterize and discover lineages with higher parasitic activity with good adaptation to the different enviroments where these agents will be used