Measuring Dark Matter Profiles Non-Parametrically In Dwarf Spheroidals: An Application To Draco

We introduce a novel implementation of orbit-based (or Schwarzschild) modeling that allows dark matter density profiles to be calculated non-parametrically in nearby galaxies. Our models require no assumptions to be made about velocity anisotropy or the dark matter profile. The technique can be applied to any dispersion-supported stellar system, and we demonstrate its use by studying the Local Group dwarf spheroidal galaxy (dSph) Draco. We use existing kinematic data at larger radii and also present 12 new radial velocities within the central 13 pc obtained with the VIRUS-W integral field spectrograph on the 2.7 m telescope at McDonald Observatory. Our non-parametric Schwarzschild models find strong evidence that the dark matter profile in Draco is cuspy for 20 = 20 pc is well fit by a power law with slope alpha = -1.0 +/- 0.2, consistent with predictions from cold dark matter simulations. Our models confirm that, despite its low baryon content relative to other dSphs, Draco lives in a massive halo.NSF-0908639Astronom

Specialized odorant receptors in social insects that detect cuticular hydrocarbon cues and candidate pheromones.

Eusocial insects use cuticular hydrocarbons as components of pheromones that mediate social behaviours, such as caste and nestmate recognition, and regulation of reproduction. In ants such as Harpegnathos saltator, the queen produces a pheromone which suppresses the development of workers' ovaries and if she is removed, workers can transition to a reproductive state known as gamergate. Here we functionally characterize a subfamily of odorant receptors (Ors) with a nine-exon gene structure that have undergone a massive expansion in ants and other eusocial insects. We deorphanize 22 representative members and find they can detect cuticular hydrocarbons from different ant castes, with one (HsOr263) that responds strongly to gamergate extract and a candidate queen pheromone component. After systematic testing with a diverse panel of hydrocarbons, we find that most Harpegnathos saltator Ors are narrowly tuned, suggesting that several receptors must contribute to detection and discrimination of different cuticular hydrocarbons important in mediating eusocial behaviour.Cuticular hydrocarbons (CHC) mediate the interactions between individuals in eusocial insects, but the sensory receptors for CHCs are unclear. Here the authors show that in ants such as H. saltator, the 9-exon subfamily of odorant receptors (HsOrs) responds to CHCs, and ectopic expression of HsOrs in Drosophila neurons imparts responsiveness to CHCs

AS (IM) POSSIBILIDADES NO MERCADO DE TRABALHO BRASILEIRO AOS REFUGIADOS

RESUMO: As transformações societárias tem promovido uma sociedade de mercado que obriga centenas de milhares de pessoas a viver a realidade migratória, em especial, com características de refugiado. Essa reflexão teórica - bibliográfica buscará refletir sobre como ocorre a inserção desses refugiados (migrantes em situação de guerras religiosas, étnicas e políticas) no mercado de trabalho no Brasil. Propõe-se realizar reflexões, bem como contextualizações sobre a representatividade dos refugiados na sociedade brasileira. Concluiu-se que estes sujeitos são funcionais ao sistema, na medida em que grande parte passam a se inserir na informalidade, reforçando a precariedade das relações e condições de trabalho estabelecidas

The role of frugivorous birds and bats in the colonization of cloud forest plant species in burned areas in western Mexico

La función de las aves y los murciélagos frugívoros en la colonización de las especies vegetales del bosque nuboso en zonas afectadas por incendios en el occidente de México.— La extensión de los bosques nubosos de montaña (o bosques mesófilos) del oeste de México se ve limitada por diversos factores. En el presente estudio se pretende evaluar la contribución de las aves y los murciélagos a la dispersión y colonización de las plantas del bosque nuboso en pinares contiguos afectados por incendios de superficie. Se muestreó la lluvia de semillas y el establecimiento de plántulas durante un año en dos sitios afectados por incendios de superficie, que diferían en el tamaño del fragmento de bosque nuboso más cercano. Se encontró un total de 17 especies vegetales, la mayoría de las cuales eran árboles, arbustos y lianas propios de estados avanzados de sucesión. La distancia respecto a la fuente de semillas influyó solamente en la lluvia de semillas de un taxón (Solanum sp.), pero no tuvo efectos en la distribución de las plántulas de esta especie ni de otras. En cambio, se encontraron importantes diferencias entre los sitios, con más semillas dispersadas y una mayor densidad de plántulas en el que estaba situado junto al fragmento más extenso de bosque nuboso. La función de los vectores de dispersión a larga distancia y la existencia de bancos de semillas previos al incendio podrían explicar la escasa importancia de la distancia desde la fuente de semillas para la lluvia de semillas y la distribución de las plántulas. En todo caso, la dispersión mediante las aves y los murciélagos antes o después del incendio facilita la regeneración y la conservación del bosque nuboso en zonas perturbadas que anteriormente hubieran estado ocupadas por otros hábitats.The role of frugivorous birds and bats in the colonization of cloud forest plant species in burned areas in western Mexico.— The extension of montane cloud forests in western Mexico is threatened by several disturbances that limit their extension. In this study we aim to assess the contribution of birds and bats in the dispersal and colonization of cloud–forest plants in contiguous surface–burned pine forests. We sampled seed rain and sapling establishment over one year in two surface–burned sites, which differed in the size of their closest cloud forest patch. A total of 17 plant species were found, most of which were late–successional trees, shrubs and climbers. Distance influenced the seed rain of only one dispersed taxon (Solanum sp.) and had no effect on the sapling distribution of this or other plants. In turn, marked differences were found between sites, with more seeds dispersed and higher sapling density in the site that was next to the larger cloud forest patch. The role of long–distance dispersers and the existence of seed banks before fire could explain the little importance of distance from seed source on seed dispersal and sapling distribution. Nevertheless, dispersal by birds and bats before or after fire facilitates the regeneration and conservation of cloud forests in disturbed areas formerly occupied by other habitats

Cyclooxygenase-2 Inhibition Restored Endothelium-Mediated Relaxation in Old Obese Zucker Rat Mesenteric Arteries

Metabolic syndrome is associated with reduced endothelial vasodilator function. It is also associated with the induction of cyclooxygenase-2 (COX2), which produces vasoactive prostanoids. The frequency of metabolic syndrome increases with age and aging per se is a risk factor associated with reduced endothelium-mediated relaxation. Nevertheless, the combined effect of aging and metabolic syndrome on the endothelium is less known. We hypothesized that COX2 derived prostanoids may affect endothelium function in metabolic syndrome associated with aging. We used obese Zucker rats, a model of metabolic syndrome. First order mesenteric arteries were isolated from 4- and 12-month-old rats and acetylcholine (endothelium)-dependent relaxation determined using wire-myography. Endothelium-mediated relaxation, impaired in young Zucker rats (89 versus 77% maximal relaxation; lean versus Zucker), was further reduced in old Zucker rats (72 versus 51%, lean versus Zucker). The effect of the nitric oxide-synthesis inhibitor L-NAME on the relaxation was reduced in both young and old Zucker rats without change in eNOS expression level. COX inhibition (indomethacin) improved acetylcholine-mediated relaxation in old obese rats only, suggesting involvement of vasoconstrictor prostanoids. In addition, COX2 inhibition (NS398) and TxA2/PGH2 receptor blockade (SQ29548) both improved relaxation in old Zucker rat arteries. Old Zucker rats had the highest TxB2 (TxA2 metabolite) blood level associated with increased COX2 immunostaining. Chronic COX2 blockade (Celecoxib, 3 weeks) restored endothelium-dependent relaxation in old Zucker rats to the level observed in old lean rats. Thus the combination of aging and metabolic syndrome further impairs endothelium-dependent relaxation by inducing an excessive production of COX2-derived vasoconstrictor(s); possibly TxA2

Dithienylethene-Based Gated Ambichromic Dyads

A set of dithienylethene (DTE)-based ambichromic dyads containing an acido-, photo-, and electrosensitive indolino[2,1-b]oxazolidine (BOX) unit displays gated photochromism. Ring opening of BOX prevents photoinduced electrocylization between open and closed forms of DTE. The photochromic performances are regenerated by two different pathways. NMR and electrochemical studies evidence interactions between indolenium and phenyl–thienyl sidearms

Dark Matter Subhalos in the Ursa Minor Dwarf Galaxy

Through numerical simulations, we study the dissolution timescale of the Ursa Minor cold stellar clump, due to the combination of phase-mixing and gravitational encounters with compact dark substructures in the halo of Ursa Minor. We compare two scenarios; one where the dark halo is made up by a smooth mass distribution of light particles and one where the halo contains 10% of its mass in the form of substructures (subhalos). In a smooth halo, the stellar clump survives for a Hubble time provided that the dark matter halo has a big core. In contrast, when the point-mass dark substructures are added, the clump survives barely for \sim 1.5 Gyr. These results suggest a strong test to the \Lambda-cold dark matter scenario at dwarf galaxy scale.Comment: accepted for publication in Ap