Radio Linear Polarization of GRB Afterglows:Instrumental Systematics in ALMA Observations of GRB 171205A

Polarization measurements of gamma-ray burst (GRB) afterglows are a promising means of probing the structure, geometry, and magnetic composition of relativistic GRB jets. However, a precise treatment of instrumental calibration is vital for a robust physical interpretation of polarization data, requiring tests of and validations against potential instrumental systematics. We illustrate this with ALMA Band 3 (97.5 GHz) observations of GRB 171205A taken $\approx5.19$ days after the burst, where a detection of linear polarization was recently claimed. We describe a series of tests for evaluating the stability of polarization measurements with ALMA. Using these tests to re-analyze and evaluate the archival ALMA data, we uncover systematics in the polarization calibration at the $\approx0.09\%$ level. We derive a 3$\sigma$ upper limit on the linearly polarized intensity of $P<97.2~\mu$Jy, corresponding to an upper limit on the linear fractional polarization of $\Pi_{\rm L}<0.30\%$, in contrast to the previously claimed detection. Our upper limit improves upon existing constraints on the intrinsic polarization of GRB radio afterglows by a factor of 3. We discuss this measurement in the context of constraints on the jet magnetic field geometry. We present a compilation of polarization observations of GRB radio afterglows, and demonstrate that a significant improvement in sensitivity is desirable for eventually detecting signals polarized at the $\approx0.1\%$ level from typical radio afterglows.Comment: 10 pages, 8 figures. Accepted for publication in Ap

Dust and Gas in the disc of HL Tauri: Surface density, dust settling, and dust-to-gas ratio

The recent ALMA observations of the disc surrounding HL Tau reveal a very complex dust spatial distribution. We present a radiative transfer model accounting for the observed gaps and bright rings as well as radial changes of the emissivity index. We find that the dust density is depleted by at least a factor 10 in the main gaps compared to the surrounding rings. Ring masses range from 10-100 M$_{\oplus}$ in dust, and, we find that each of the deepest gaps is consistent with the removal of up to 40 M$_{\oplus}$ of dust. If this material has accumulated into rocky bodies, these would be close to the point of runaway gas accretion. Our model indicates that the outermost ring is depleted in millimetre grains compared to the central rings. This suggests faster grain growth in the central regions and/or radial migration of the larger grains. The morphology of the gaps observed by ALMA - well separated and showing a high degree of contrast with the bright rings over all azimuths - indicates that the millimetre dust disc is geometrically thin (scale height $\approx$ 1 au at 100 au) and that a large amount of settling of large grains has already occurred. Assuming a standard dust settling model, we find that the observations are consistent with a turbulent viscosity coefficient of a few $10^{-4}$. We estimate the gas/dust ratio in this thin layer to be of the order of 5 if the initial ratio is 100. The HCO$^+$ and CO emission is consistent with gas in Keplerian motion around a 1.7 $M_\odot$ star at radii from $\leq 10 - 120\,$au.Comment: 12 pages, 8 figures, published in ApJ, same version as before but with slightly extended discussion on temperature and masses to account for literature published since initial submissio

Linguística e Comunicação: os Elementos de um Paradigma

In this article I argue in favor of a theory of communication that encompasses interindividual sociocultural differences in the communicative language behavior into a general theory of communication. In this sense I review some of the basic concepts of the Interactional Sociolinguistics and discuss its model of communication. Key concepts here are: interactive process, situated speech, contextualization cues, involvement in discourse, self, face, cooperation and language problems

DAYLIGHT SAVING TIME AND HOMICIDES: LIGHT EFFECT IN CRIMES OF A BRAZILIAN STATE

This article analyzes the effect of daylight saving time (DST) on crimes inthe Brazilian state of Rio Grande do Sul. With the argument that DST provides “more”hours of light throughout the day, it is expected that the criminal behavior will reduce atits implantation, since a clearer environment can dissuade the potential criminal. Making use of several regression discontinuity design (RDD) models and a daily databaseranging from 2006 to 2014 of the Mortality Information System (SIM) of Datasus, themodels were estimated separately by year, being able to include wheater independentvariables (such as temperature, precipitation and wind speed) and fixed effects of daysof the week. It was evidenced that DST has no significant effect on changes in homiciderates per 100,000 inhabitants, neither in its beginning, nor its end. On the other hand,it has been found that, in general, there is a strong weekend effect on criminal activityand some evidence that homicide rates are related to temperature.Este artigo analisa o efeito do horário de verão (HV) sobre os crimes no estado do Rio Grande do Sul (BR). Com o argumento de que o HV fornece “mais” horasde luz ao longo do dia, espera-se que o comportamento criminoso diminua na suaimplantação, uma vez que um ambiente mais claro pode dissuadir o potencial criminoso. Utilizando diversos modelos de regressão descontinuidade e um banco de dadosdiário de 2006 a 2014 do Sistema de Informações sobre Mortalidade (SIM) do Datasus,os modelos foram estimados separadamente por ano, podendo incluir variáveis independentes de maior temperatura (como temperatura, precipitação e velocidade dovento) e efeitos fixos de dias da semana. Evidenciou-se que o HV não tem efeito significativo na mudança das taxas de homicídio por 100.000 habitantes, nem em seu início,nem em seu fim. Por outro lado, verificou-se que, em geral, há um forte efeito de fim desemana sobre a atividade criminosa e algumas evidências de que as taxas de homicídioestão relacionadas à temperatura

Coinfection of Leishmania (Viannia) braziliensis and Streptococcus pneumoniae in multiple cutaneous lesions

Key learning points Cutaneous leishmaniasis is the most common clinical disease caused by all the Leishmania species that are pathogenic to humans. Other bacterial coinfections of Leishmania lesions have been described, but this is the first report of coinfection with Leishmania and S. pneumoniae. S. pneumoniae is also able to cause skin infections, for that reason the pneumococcal diagnosis could be underestimated in Leishmania lesions coinfected with bacterial pathogens, particularly in endemic areas. An accurate microbiological diagnosis of Leishmania coinfections is essential for a correct antimicrobial treatment of skin infections.. Pentavalent antimonials, such as meglumine antimoniate, are considered the first-line antimicrobial therapy for the treatment of leishmaniasis.Fil: Cortes, Paulo R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Chiapello, Laura Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; ArgentinaFil: Dib, David. Hospital Pediátrico del Niño Jesús; ArgentinaFil: Herrero, Mónica V.. Hospital Córdoba; ArgentinaFil: Nuncira, Carmen T.. Hospital Pediátrico del Niño Jesús; ArgentinaFil: De Petris, Carlos. Hospital Pediátrico del Niño Jesús; ArgentinaFil: Echenique, Jose Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; Argentin

Interferometric Mapping of Magnetic fields: NGC2071IR

We present polarization maps of NGC2071IR from thermal dust emission at 1.3 mm and from CO J=$2 \to 1$ line emission. The observations were obtained using the Berkeley-Illinois-Maryland Association array in the period 2002-2004. We detected dust and line polarized emission from NGC2071IR that we used to constrain the morphology of the magnetic field. From CO J=$2 \to 1$ polarized emission we found evidence for a magnetic field in the powerful bipolar outflow present in this region. We calculated a visual extinction $A_{\rm{v}} \approx 26$ mag from our dust observations. This result, when compared with early single dish work, seems to show that dust grains emit polarized radiation efficiently at higher densities than previously thought. Mechanical alignment by the outflow is proposed to explain the polarization pattern observed in NGC2071IR, which is consistent with the observed flattening in this source.Comment: 17 pages, 4 Figures, Accepted for publication in Ap

O ESPAÇO DE TRANSIÇÃO DE FALANTES EM AUDIÊNCIAS DE CONCILIAÇÃO NO PROCON: LUGAR RELEVANTE PARA O DESACORDO?

ABSTRACT – The study explores aspects of the organization from the turns of speak and conversational sequence in Analysis of the Ethnic methodological Colloquy to argue the process of transition from speakers in meetings of conciliation in PROCON. The examination of some practical of taking from turn in this scene discloses an accomplishment anticipated of disagreement acts, in not excellent places for the transition from speakers. Such characteristic must over all to the conflict context, where the disagreement act gains prominence in the interaction. It is corroborated, finally, the Gruber perspective (1998), according to which, in determined conflict contexts, can be spoken in an excellent place for the disagreement

The (re)formulation practice as an argumentative strategy in conflict situation

The article analyzes actual data of talk-in-interaction in a conflict situation and proposes to combine the formulation practice in ethnomethodological Conversation Analysis to the interactional perspective of argument. In a pilot qualitative case study, we follow the trajectory of an argumentative process of a combined sale in a conciliation hearing at PROCON. We specifically show how the (re)formulations are connected to the (re)introduction of positions and supports. We argue that both complement each other because, as the argument is a basic function of language and central in the legal world, the formulation is also an important practice because it is present in all contexts. We defend interaction as a privileged locus of human experience.Keywords: formulation practice, argumentative strategy, interaction in conflict situation.</p

A prática de (re)formulação como estratégia argumentativa em situação de conflito

The article analyzes actual data of talk-in-interaction in a conflict situation and proposes to combine the formulation practice in ethnomethodological Conversation Analysis to the interactional perspective of argument. In a pilot qualitative case study, we follow the trajectory of an argumentative process of a combined sale in a conciliation hearing at PROCON. We specifically show how the (re)formulations are connected to the (re)introduction of positions and supports. We argue that both complement each other because, as the argument is a basic function of language and central in the legal world, the formulation is also an important practice because it is present in all contexts. We defend interaction as a privileged locus of human experience.Keywords: formulation practice, argumentative strategy, interaction in conflict situation.O artigo analisa dados reais de fala-em-interação em situação de conflito e propõe conjugar a prática de formulação em Análise da Conversa Etnometodológica à perspectiva interacional de argumentação. Em um estudo de caso, piloto, qualitativo, acompanhamos a trajetória do processo argumentativo de um caso de venda casada em uma audiência de conciliação no PROCON. Mostramos, especificamente, como as (re)formulações estão ligadas à (re)introdução de posições e de sustentações. Argumentamos que ambas complementam-se, pois, assim como a argumentação é uma função básica da linguagem e central no universo jurídico, a formulação é prática igualmente relevante, pois é presente em todos os contextos. Defendemos a interação como lócus privilegiado da experiência humana.Palavras-chave: prática de formulação, estratégia argumentativa, interação em situação de conflito