LSST: from Science Drivers to Reference Design and Anticipated Data Products

(Abridged) We describe here the most ambitious survey currently planned in the optical, the Large Synoptic Survey Telescope (LSST). A vast array of science will be enabled by a single wide-deep-fast sky survey, and LSST will have unique survey capability in the faint time domain. The LSST design is driven by four main science themes: probing dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. LSST will be a wide-field ground-based system sited at Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg$^2$ field of view, and a 3.2 Gigapixel camera. The standard observing sequence will consist of pairs of 15-second exposures in a given field, with two such visits in each pointing in a given night. With these repeats, the LSST system is capable of imaging about 10,000 square degrees of sky in a single filter in three nights. The typical 5$\sigma$ point-source depth in a single visit in $r$ will be $\sim 24.5$ (AB). The project is in the construction phase and will begin regular survey operations by 2022. The survey area will be contained within 30,000 deg$^2$ with $\delta<+34.5^\circ$, and will be imaged multiple times in six bands, $ugrizy$, covering the wavelength range 320--1050 nm. About 90\% of the observing time will be devoted to a deep-wide-fast survey mode which will uniformly observe a 18,000 deg$^2$ region about 800 times (summed over all six bands) during the anticipated 10 years of operations, and yield a coadded map to $r\sim27.5$. The remaining 10\% of the observing time will be allocated to projects such as a Very Deep and Fast time domain survey. The goal is to make LSST data products, including a relational database of about 32 trillion observations of 40 billion objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures available from https://www.lsst.org/overvie

A História da Alimentação: balizas historiográficas

Os M. pretenderam traçar um quadro da História da Alimentação, não como um novo ramo epistemológico da disciplina, mas como um campo em desenvolvimento de práticas e atividades especializadas, incluindo pesquisa, formação, publicações, associações, encontros acadêmicos, etc. Um breve relato das condições em que tal campo se assentou faz-se preceder de um panorama dos estudos de alimentação e temas correia tos, em geral, segundo cinco abardagens Ia biológica, a econômica, a social, a cultural e a filosófica!, assim como da identificação das contribuições mais relevantes da Antropologia, Arqueologia, Sociologia e Geografia. A fim de comentar a multiforme e volumosa bibliografia histórica, foi ela organizada segundo critérios morfológicos. A seguir, alguns tópicos importantes mereceram tratamento à parte: a fome, o alimento e o domínio religioso, as descobertas européias e a difusão mundial de alimentos, gosto e gastronomia. O artigo se encerra com um rápido balanço crítico da historiografia brasileira sobre o tema

Reproduction coopérative et possible paternité multiple chez le Cossyphe à calotte blanche Cossypha albicapilus, supposé monogame

[EN] We report a case of cooperative breeding and putative multiple paternity in a nest of the White-crowned Robin-Chat Cossypha albicapillus. These phenomena have not been reported previously in this species and closely-related robin-chats. In a nest found in The Gambia we observed at least five adults feeding or visiting the young. We genotyped four adults (one female, three males) and the two young using a microsatellite marker previously developed for another species. The genotype data were consistent with the female being the mother of the two nestlings, but paternal alleles suggested two different males as fathers of the nestlings. Our observations show that cooperative breeding occurs in the White-crowned Robin-Chat, and that monogamy may not be as universal in this species as previously assumed.[FR] Nous rendons compte d’un cas de reproduction coopérative et paternité multiple putative dans un nid de Cossyphe à calotte blanche Cossypha albicapillus. Ces phénomènes n’ont pas jusqu’ici été rapportés pour cette espèce et les cossyphes proches. Dans un nid trouvé en Gambie, nous avons observé au moins cinq adultes de cette espèce nourrissant ou visitant les jeunes. Nous avons analysé le génome de quatre adultes (une femelle, trois mâles) et des deux jeunes en utilisant un marqueur microsatellite développé pour une autre espèce. Les données des génotypes étaient cohérentes avec l’hypothèse que la femelle était la mère des deux poussins, mais les allèles paternels suggéraient que deux mâles différents étaient les pères des poussins. Nos observations montrent qu’il peut y avoir une reproduction coopérative chez le Cossyphe à calotte blanche, et que cette espèce n’est pas toujours monogame comme on le supposait.The study was partially funded by a grant from the Royal Society of London to PJBS.Peer reviewe

The influence of social affiliation on individual vocal signatures of northern resident killer whales (Orcinus orca)

Northern resident killer whales (Orcinus orca) live in highly stable groups and use group-specific vocal signals, but individual variation in calls has not been described previously. A towed beam-forming array was used to ascribe stereotyped pulsed calls with two independently modulated frequency contours to visually identified individual killer whales in Johnstone Strait, British Columbia. Overall, call similarity determined using neural networks differed significantly between different affiliation levels for both frequency components of all the call types analysed. This method distinguished calls from individuals within the same matriline better than different calls produced by a single individual and better than by chance. The calls of individuals from different matrilines were more distinctive than those within the same matriline, confirming previous studies based on group recordings. These results show that frequency contours of stereotyped calls differ among the individuals that are constantly associated with each other and use group-specific vocalizations, though across-group differences were substantially more pronounced

An experimental study of duet integration in the happy wren, Pheugopedius felix

Pairs of duetting birds can sing coordinated duets with such precision that they are often mistaken for a single individual, yet little is known about how this impressive temporal synchronization is achieved. We experimentally examined duet coordination in male happy wrens, held briefly in captivity, by playing song phrases from their partner at different distances and tempos. Males were more likely to respond to songs played nearby, but did not vary their amplitude to compensate for their partner's simulated distance. Males modified their song rate to match the manipulated female playback tempo, indicating that they listen and respond to each female utterance. Each happy wren has a sex-specific repertoire of about 40 different song phrases and pairs combine particular phrases according to pair-specific duet ‘codes’, creating a further challenge for coordinating duets. We found that most males produced the appropriate phrase to reply to the female playback song in the absence of any other potential cues, sometimes delivering the correct song phrase type within 0.5 s of the start of the very first female playback heard. These experiments demonstrate rapid decision making and vocal production, indicative of sophisticated underlying cognitive processing, and provide a novel experimental technique to investigate the mechanisms controlling vocal duets