Polarimetry and photometry of the peculiar main-belt object 7968 = 133P/Elst-Pizarro

133P/Elst-Pizarro is an object that has been described as either an active asteroid or a cometary object in the main asteroid belt. Here we present a photometric and polarimetric study of this object in an attempt to infer additional information about its origin. With the FORS1 instrument of the ESO VLT, we have performed during the 2007 apparition of 133P/Elst-Pizarro quasi-simultaneous photometry and polarimetry of its nucleus at nine epochs in the phase angle range 0 - 20 deg. For each observing epoch, we also combined all available frames to obtain a deep image of the object, to seek signatures of weak cometary activity. Polarimetric data were analysed by means of a novel physical interference modelling. The object brightness was found to be highly variable over timescales <1h, a result fully consistent with previous studies. Using the albedo-polarization relationships for asteroids and our photometric results, we found for our target an albedo of about 0.06-0.07 and a mean radius of about 1.6 km. Throughout the observing epochs, our deep imaging of the comet detects a tail and an anti-tail. Their temporal variations are consistent with an activity profile starting around mid May 2007 of minimum duration of four months. Our images show marginal evidence of a coma around the nucleus. The overall light scattering behaviour (photometry and polarimetry) resembles most closely that of F-type asteroids.Comment: Accepted by Astronomy and Astrophysic

Determinantes Sensoriais na Escolha dos Alimentos

A escolha alimentar é um processo complexo que envolve fatores sócio- culturais, económicos, psicológicos, ambientais, e factores relacionados com as caracteristicas, os atributos dos vários alimentos. O conhecimento de tais determinantes do consumo alimentar é uma ferramenta importante para a prevenção e mudança de comportamentos de risco e a escolha de outros saudáveis. Vários autores discutem sobre a necessidade de reflexão de abordagens metodológicas pluridisciplinares na tentativa de melhorar a compreensão deste mecanismo. O principal motor para a alimentação é, obviamente, a fome, mas o que escolhemos comer não é determinado exclusivamente por necessidades fisiológicas ou nutricionais. Alguns dos outros principais fatores que influenciam a escolha dos alimentos incluem (1) l Determinantes biológicos ( tais como a fome, o apetite e, aspetos sensoriais) , (2) Determinantes económicos( tais como o custo, o rendimento e a disponibilidade) (3) Determinantes físicos ( tais como acesso, a educação, as competências , (4) Determinantes sociais( tais como a cultura, a família, os colegas e os padrões de refeições, (5) Determinantes psicológicos ( tais como o humor, o stress e a culpa) e (6) Atitudes, crenças e conhecimentos sobre alimentos. Neste trabalho é apresentado uma reflexão sobre as determinantes sensoriais na escolha dos alimentos, aspectos metodológicos e suas consequências para os diferentes grupos da polução

Evolution of the Dust Coma in Comet 67P/Churyumov-Gerasimenko Before 2009 Perihelion

Comet 67P/Churyumov-Gerasimenko is the main target of ESA's Rosetta mission and will be encountered in May 2014. As the spacecraft shall be in orbit the comet nucleus before and after release of the lander {\it Philae}, it is necessary necessary to know the conditions in the coma. Study the dust environment, including the dust production rate and its variations along its preperihelion orbit. The comet was observed during its approach to the Sun on four epochs between early-June 2008 and mid-January 2009, over a large range of heliocentric distances that will be covered by the mission in 2014. An anomalous enhancement of the coma dust density was measured towards the comet nucleus. The scalelength of this enhancement increased with decreasing heliocentric distance of the comet. This is interpreted as a result of an unusually slow expansion of the dust coma. Assuming a spherical symmetric coma, the average amount of dust as well as its ejection velocity have been derived. The latter increases exponentially with decreasing heliocentric distance (\rh), ranging from about 1 m/s at 3 AU to about 25-35 m/s at 1.4 AU. Based on these results we describe the dust environment at those nucleocentric distances at which the spacecraft will presumably be in orbit. Astronomy and Astrophysics, in pressComment: 5 pages, 4 figure

Refurbishing Voyager 1 & 2 Planetary Radio Astronomy (PRA) Data

Voyager/PRA (Planetary Radio Astronomy) data from digitized tapes archived at CNES have been reprocessed and recalibrated. The data cover the Jupiter and Saturn flybys of both Voyager probes. We have also reconstructed goniopolarimetric datasets (flux and polarization) at full resolution. These datasets are currently not available to the scientific community, but they are of primary interest for the analysis of the Cassini data at Saturn, and the Juno data at Jupiter, as well as for the preparation of the JUICE mission. We present the first results derived from the re-analysis of this dataset.Comment: Accepted manuscript for PRE8 (Planetary Radio Emission VIII conference) proceeding

Normal subgroups in the Cremona group (long version)

Let k be an algebraically closed field. We show that the Cremona group of all birational transformations of the projective plane P^2 over k is not a simple group. The strategy makes use of hyperbolic geometry, geometric group theory, and algebraic geometry to produce elements in the Cremona group that generate non trivial normal subgroups.Comment: With an appendix by Yves de Cornulier. Numerous but minors corrections were made, regarding proofs, references and terminology. This long version contains detailled proofs of several technical lemmas about hyperbolic space

Cheese sensory evaluation

Sensory evaluation is a scientific discipline used to evoke, measure, analyse, and interpreted reactions to characteristics of food as they are perceived by senses of sight, smell, taste, touch, and hearing. Without the proper sensory evaluations techniques (sensorial methodology) it is difficult to assess sensory responses and make logical and sound decisions. Many different types of sensorial methods have been proposed and used to select, trained a sensorial panel and to evaluate and control the sensory quality of cheeses. However, not all of them are suitable for all purpose. According the objectives and the cheese sample, it will be proposed a sensory methods that can be used to define sensory specifications or to select a cheese quality standard. It is important to recognise the the glossary of the cheese terms sensory evaluation, to get a lawful cheese sensory evaluation. Based on the main cheese characteristics ( external appearance, texture, and flavour), that are different and specific of each kind a cheese, sensory cheese evaluation is described and validated in 3 cheese samples

Effects of methylprednisolone on exercise-induced increases of plasma levels of polymorphonuclear elastase and myeloperoxidase in man. Preliminary results

The aim of the present study was to verify whether a single oral dose of methylprednisolone could modulate the exercise-induced release of polymorphonuclear neutrophil (PMN) elastase and myeloperoxidase. Four healthy, male subjects were submitted to a 20 min downhill run (−20%) at 60% VO2 max, 3 h after oral absorption of a placebo or a single dose of 32 mg methylprednisolone. A marked neutrophilia (+103% of basal PMN count; p < 0.02) was observed 3 h after methylprednisolone ingestion. During both exercise trials, placebo and methylprednisolone, PMN counts were increased by 46% and 19% (p < 0.05), respectively. The running test caused marked and significant (p < 0.05) increases in plasma myeloperoxidase concentration (MPO). The magnitude of MPO changes was the same in the two trials (+110%). Exercise also resulted in significant changes in plasma elastase concentration (EL) in both experimental conditions (placebo: +104%, p < 0.05; methylprednisolone: +338%, p < 0.005). Plasma elastase levels reached at the end of exercise on methylprednisolone were significantly higher than after placebo (p < 0.05). A significant relationship was found between EL and PMN in methylprednisolone trial only (r = 0.72; l0 < 0.005). These results showed that the transient exercise-induced release of elastase and myeloperoxidase were not decreased by methylprednisolone

Inflammatory response to strenuous muscular exercise in man

Based on the humoral and cellular changes occurring during strenuous muscular work in humans, the concept of inflammatory response to exercise (IRE) is developed. The main indices of IRE consist of signs of an acute phase response, leucocytosis and leucocyte activation, release of inflammatory mediators, tissue damage and cellular infiltrates, production of free radicals, activation of complement, and coagulation and fibrinolytic pathways. Depending on exercise intensity and duration, it seems likely that muscle and/or associated connective tissue damage, contact system activation due to shear stress on endothelium and endotoxaemia could be the triggering mechanisms of IRE. Although this phenomenon can be considered in most cases as a physiological process associated with tissue repair, exaggerated IRE could have physiopathological consequences. On the other hand, the influence of several factors such as age, sex, training, hormonal status, nutrition, anti-inflammatory drugs, and the extent to which IRE could be a potential risk for subjects undergoing intense physical training require further study

Redes sociais: comunicação e mudança

As redes sociais virtuais vieram oferecer a possibilidade de um debate aberto e plural, onde todos os que detenham a necessária literacia e meios podem participar na criação e difusão de informação. Pressionando agentes políticos e determinando a agenda de muitos media, os utilizadores demonstram estarmos ante uma plataforma ideal para a criação de verdadeiros movimentos sociais ou de eventos mais ou menos fugazes, como manifestos ou campanhas virtuais. Não obstante, para que consigamos compreender o papel das redes sociais virtuais no mundo actual, haverá que responder previamente a algumas questões. Estaremos ante um novo modelo comunicacional, onde o produto da interactividade “desinteressada” cria uma aura de confiança na informação divulgada, por vezes bem superior à presente nos old media? Será essa interactividade a possibilidade de combate a um desprendimento crescente do cidadão ante a res publica? Teremos no jornalismo do cidadão, veiculado através das redes sociais virtuais, a consagração de um verdadeiro quarto poder? Por outro lado, poderemos apelidar as diversas acções colectivas a que temos assistido de verdadeiros “movimentos sociais”? O artigo que se segue pretende abordar estas e outras questões que se colocam no intricado mundo do social cibernético