Constraints of a pulsation frequency on stellar parameters in the eclipsing spectroscopic binary system: V577 Oph

We present a preliminary spectroscopic analysis of the binary system V577Oph, observed during the summer of 2007 on the 2.6m NOT telescope on La Palma. We have obtained time series spectroscopic observations, which show clear binary motion as well as radial velocity variations due to pulsation in the primary star. By modelling the radial velocities we determine a full orbital solution of the system, which yields M_A sin^3 i = 1.562 +/- 0.012 M_solar and M_B sin^3 i = 1.461 +/- 0.020 M_solar. An estimate of inclination from photometry yields a primary mass of 1.6 M_solar. Using this derived mass, and the known pulsation frequency we can impose a lower limit of 1 Gyr on the age of the system, and constrain the parameters of the oscillation mode. We show that with further analysis of the spectra (extracting the atmospheric parameters), tighter constraints could be imposed on the age, metallicity and the mode parameters. This work emphasizes the power that a single pulsation frequency can have for constraining stellar parameters in an eclipsing binary system.Comment: Accepted by A

Sounding stellar cycles with Kepler - II. Ground-based observations

We have monitored 20 Sun-like stars in the Kepler field-of-view for excess flux with the FIES spectrograph on the Nordic Optical Telescope since the launch of Kepler spacecraft in 2009. These 20 stars were selected based on their asteroseismic properties to sample the parameter space (effective temperature, surface gravity, activity level etc.) around the Sun. Though the ultimate goal is to improve stellar dynamo models, we focus the present paper on the combination of space-based and ground-based observations can be used to test the age-rotation-activity relations. In this paper we describe the considerations behind the selection of these 20 Sun-like stars and present an initial asteroseismic analysis, which includes stellar age estimates. We also describe the observations from the Nordic Optical Telescope and present mean values of measured excess fluxes. These measurements are combined with estimates of the rotation periods obtained from a simple analysis of the modulation in photometric observations from Kepler caused by starspots, and asteroseismic determinations of stellar ages, to test relations between between age, rotation and activity.Comment: Accepted for publication in MNRA

Parasitic infections in two Benthopelagic fish from Amazon: the Arowana Osteoglossum bicirrhosum (Osteoglossidae) and Oscar Astronotus ocellatus (Cichlidae).

The parasitic fauna of wild Osteoglossum bicirrhosum from central Amazon (Brazil) and wild Astronotus ocellatus from eastern Amazon (Brazil) as well as the host-parasite relationship were evaluated. 87.5% O. bicirrhosum were parasitized only by Gonocleithrum aruanae (Monogenoidea). 92.8% A. ocellatus were parasitized by Ichthyophthirius multifiliis (Ciliophora), Gussevia asota (Monogenoidea), Posthodiplostomum sp. metacercariae (Diplostomidae), Procamallanus inopinatus adults and Contracaecum larvae (Anisakidae). High levels of infection by G. aruanae occurred in O. bicirrhosum while in A. ocellatus the highest levels of infection were caused by helminthes ectoparasites such as G. asota, and endoparasites such as Posthodiplostomum sp., P. inopinatus and Contracaecum sp. There was a significant (p>0.05) negative correlation between the intensity of helminthes species and the relative condition factor (Kn) from A. ocellatus, indicating that these parasites are pathogenic for hosts. The parasite fauna of O. bicirrhosum was scarce, while the parasites for A. ocellatus were mainly helminthes species, including adults and larval forms. Such differences on parasites fauna of both omnivore hosts may due to their history life as well as environmental and biological factors

Dual-resource Constrained Scheduling for Quality Control Laboratories

This work presents a novel formulation for quality control laboratory scheduling considering both equipment and analysts as constraints. The problem is modelled as a dualresource constrained exible job shop problem. The formulation considers analyst's tasks in multiple time points during the processing of samples. The mathematical model is implemented as a mixed integer linear programming model (MILP) aiming to minimize makespan. Two sets of instances for the scheduling problem are developed and solved. The rst instance consists on a small example that illustrates the proposed formulation and is solved to optimality. The second instance mimics the real industrial problem and shows the challenges resulting from growing complexity

Electrical activation and electron spin coherence of ultra low dose antimony implants in silicon

We implanted ultra low doses (2x10^11 cm-2) of 121Sb ions into isotopically enriched 28Si and find high degrees of electrical activation and low levels of dopant diffusion after rapid thermal annealing. Pulsed Electron Spin Resonance shows that spin echo decay is sensitive to the dopant depths, and the interface quality. At 5.2 K, a spin decoherence time, T2, of 0.3 ms is found for profiles peaking 50 nm below a Si/SiO2 interface, increasing to 0.75 ms when the surface is passivated with hydrogen. These measurements provide benchmark data for the development of devices in which quantum information is encoded in donor electron spins

Biomonitoramento de abelhas com Pan Traps em um sistema agroflorestal em Tomé-Açu, Pará.

A castanheira-do-brasil, Bertholletia excelsa Humb. (Lecythidaceae) é uma planta de importante interesse econômico na Amazônia que depende da polinização por abelhas nativas e vem sendo usada em sistemas agroflorestais (SAFs) no nordeste paraense há mais de cinco décadas. O presente trabalho teve como objetivo estimar a fauna de abelhas em um SAF com castanheira e comparar com outros sistemas de cultivo da propriedade. Para isso, foi realizado um inventário mensal de abelhas utilizando-se pratos armadilhas ou pan-traps (recipientes de diferentes cores contendo água e gotas de detergente), conhecidos por atraírem alta diversidade desses insetos. Esse trabalho foi realizado na Fazenda Sasahara, localidade Quatro-Bocas, município Tomé-Açu/PA, nos meses de Agosto/2010 a Janeiro/2011. Foram capturados 109 indivíduos distribuídos em 17 espécimes. Com relação à atratividade das cores dos pan-traps, os de coloração azul foram mais eficientes, capturando 88 abelhas, seguido dos amarelos com 16 e dos brancos com cinco indivíduos.Editores técnicos: Roberto Porro, Milton Kanashiro, Maria do Socorro Gonçalves Ferreira, Leila Sobral Sampaio e Gladys Ferreira de Sousa

Models for Chronology Selection

In this paper, we derive an expression for the grand canonical partition function for a fluid of hot, rotating massless scalar field particles in the Einstein universe. We consider the number of states with a given energy as one increases the angular momentum so that the fluid rotates with an increasing angular velocity. We find that at the critical value when the velocity of the particles furthest from the origin reaches the speed of light, the number of states tends to zero. We illustrate how one can also interpret this partition function as the effective action for a boosted scalar field configuration in the product of three dimensional de Sitter space and $S^1$. In this case, we consider the number of states with a fixed linear momentum around the $S^1$ as the particles are given more and more boost momentum. At the critical point when the spacetime is about to develop closed timelike curves, the number of states again tends to zero. Thus it seems that quantum mechanics naturally enforces the chronology protection conjecture by superselecting the causality violating field configurations from the quantum mechanical phase space.Comment: 20 pages, Late