37 research outputs found

    Moderate drinking before the unit: medicine and life assurance in Britain and the US c.1860–1930

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    This article describes the way in which “Anstie’s Limit” – a particular definition of moderate drinking first defined in Britain in the 1860s by the physician Francis Edmund Anstie (1833–1874) – became established as a useful measure of moderate alcohol consumption. Becoming fairly well-established in mainstream Anglophone medicine by 1900, it was also communicated to the public in Britain, North America and New Zealand through newspaper reports. However, the limit also travelled to less familiar places, including life assurance offices, where a number of different strategies for separating moderate from excessive drinkers emerged from the dialogue between medicine and life assurance. Whilst these ideas of moderation seem to have disappeared into the background for much of the twentieth century, re-emerging as the “J-shaped” curve, these early developments anticipate many of the questions surrounding uses of the “unit” to quantify moderate alcohol consumption in Britain today. The article will therefore conclude by exploring some of the lessons of this story for contemporary discussions of moderation, suggesting that we should pay more attention to whether these metrics work, where they work and why

    Processing GOTO data with the Rubin Observatory LSST Science Pipelines I: Production of coadded frames

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    The past few decades have seen the burgeoning of wide field, high cadence surveys, the most formidable of which will be the Legacy Survey of Space and Time (LSST) to be conducted by the Vera C. Rubin Observatory. So new is the field of systematic time-domain survey astronomy, however, that major scientific insights will continue to be obtained using smaller, more flexible systems than the LSST. One such example is the Gravitational-wave Optical Transient Observer (GOTO), whose primary science objective is the optical follow-up of Gravitational Wave events. The amount and rate of data production by GOTO and other wide-area, high-cadence surveys presents a significant challenge to data processing pipelines which need to operate in near real-time to fully exploit the time-domain. In this study, we adapt the Rubin Observatory LSST Science Pipelines to process GOTO data, thereby exploring the feasibility of using this "off-the-shelf" pipeline to process data from other wide-area, high-cadence surveys. In this paper, we describe how we use the LSST Science Pipelines to process raw GOTO frames to ultimately produce calibrated coadded images and photometric source catalogues. After comparing the measured astrometry and photometry to those of matched sources from PanSTARRS DR1, we find that measured source positions are typically accurate to sub-pixel levels, and that measured L-band photometries are accurate to ∼50 mmag at mL∼16 and ∼200 mmag at mL∼18. These values compare favourably to those obtained using GOTO's primary, in-house pipeline, GOTOPHOTO, in spite of both pipelines having undergone further development and improvement beyond the implementations used in this study. Finally, we release a generic "obs package" that others can build-upon should they wish to use the LSST Science Pipelines to process data from other facilities

    Light curve classification with recurrent neural networks for GOTO: dealing with imbalanced data

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    The advent of wide-field sky surveys has led to the growth of transient and variable source discoveries. The data deluge produced by these surveys has necessitated the use of machine learning (ML) and deep learning (DL) algorithms to sift through the vast incoming data stream. A problem that arises in real-world applications of learning algorithms for classification is imbalanced data, where a class of objects within the data is underrepresented, leading to a bias for over-represented classes in the ML and DL classifiers. We present a recurrent neural network (RNN) classifier that takes in photometric time-series data and additional contextual information (such as distance to nearby galaxies and on-sky position) to produce real-time classification of objects observed by the Gravitational-wave Optical Transient Observer (GOTO), and use an algorithm-level approach for handling imbalance with a focal loss function. The classifier is able to achieve an Area Under the Curve (AUC) score of 0.972 when using all available photometric observations to classify variable stars, supernovae, and active galactic nuclei. The RNN architecture allows us to classify incomplete light curves, and measure how performance improves as more observations are included. We also investigate the role that contextual information plays in producing reliable object classification

    Karyotypic analysis of Baryancistrus

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    Three specimes of Baryancistrus aff. niveatus were studied cytogenetically by conventional staining, C banding, Ag-NORs, CMA3, DAPI and FISH with human telomeric probes. The results revealed a complement consisting of 52 metacentric, submetacentric and subtelocentric type chromosomes. C banding showed that heterochro-matin is located at pairs 1, 3, 6, 10, 11 and 22 in different positions. NORs were located at the short arm of pair 3, coinciding with a positive C-band. This region was also marked with CMA3, which also marked heterochromatic blocks in chromosomes 11 and 22. These regions were negatively stained by DAPI. These results revealed the presence of two different types of constitutive heterochromatin, probably due to their base composition. Chromosome bearing rDNA sites presented a difference in size in the NOR regions, probably due to heterochromatin and ribos-somal cistrons amplification. The localization of telomeric sequences by FISH revealed the conservative nature of this region. © 2004 Taylor & Francis Group, LLC

    Embryology and cytogenetics of Eupatorium pauciflorum and E. intermedium (Compositae)

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    The embryology of Eupatorium pauciflorum indicates diplospory with autonomous endosperm development. The embryo sac is of the polygonum type and the polar nuclei mostly fuse before anthesis. The occurrence of precocious embryo and endosperm development in unopened florets, and the total absence of germinated pollen grains on exposed stigmas, as well as the absence of pollen tubes in the ovules, indicate agamospermy to be obligate and embryo and endosperm development autonomous. The study of microsporogenesis revealed the total absence of pollen production in consequence of microsporocyte degeneration before the onset of meiosis, which resulted in absolute male sterility. E. pauciflorum was demonstrated to be an autotriploid with a basic set of 10 chromosomes, each represented three times. Embryological studies showed E. intermedium to undergo reductive meiosis with tetrad formation during megasporogenesis, followed by monosporic embryo sac development of the polygonum type. The polar nuclei fuse before anthesis. The egg cell invariably attains anthesis still undivided, without precocious embryony. Meiosis of microsporogenesis results in the regular formation of 10 bivalents and the subsequent stages of microsporogenesis are normal. Stigmatic loads indicate the regular occurrence of pollination with viable, functional grains. Karyotypic studies revealed a complement of 20 chromosomes separable into 10 pairs. It is concluded that E. pauciflorum, as represented by the material studied, is apomictic while E. intermedium is sexual.<br>Os estudos embriológicos indicam que Eupatorium pauciflorum apresenta diplosporia com desenvolvimento autônomo do endosperma. O saco embrionário é do tipo polygonum e os núcleos polares se fundem antes da antese. A ocorrência de embrionia precoce e desenvolvimento do endosperma em flores fechadas, e a total ausência de grãos de pólen germinados em estigmas expostos, bem como a ausência de tubos polínicos nos óvulos, indicam que agamospermia é obrigatória e o desenvolvimento do embrião e do endosperma é autônomo. O estudo da microsporogênese revelou completa ausência de produção de pólen, em razão da degeneração dos microsporócitos antes do início da meiose, o que resulta em absoluta esterilidade masculina. E. pauciflorum demonstrou ser autotriplóide com um conjunto básico de 10 cromossomos repetidos três vezes. Os estudos embriológicos mostraram que E. intermedium sofre meiose reducional, com formação de tétrades durante a megasporogênese, seguida pelo desenvolvimento monospórico do saco embrionário do tipo polygonum. Os núcleos polares se fundem antes da antese. A oosfera invariavelmente permanece até a antese sem se dividir, impedindo a ocorrência de embrionia precoce. A meiose da microsporogênese resulta na formação regular de 10 bivalentes; os estágios subseqüentes da microsporogênese são normais e a análise da superfície estigmática indica a ocorrência regular de polinização, com grãos de pólen viáveis e funcionais. Estudos de cariótipo revelaram um complemento de 20 cromossomos separados em 10 pares. É possível concluir que E. pauciflorum, como representada pelo material estudado, é apomítica, enquanto E. intermedium é sexuada
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