300 research outputs found

    On the Nature of Long-Period Dwarf Novae with Rare and Low-Amplitude Outbursts

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    There are several peculiar long-period dwarf-nova like objects, which show rare, low-amplitude outbursts with highly ionized emission lines. 1SWASP J162117++441254, BD Pav, and V364 Lib belong to this kind of objects. Some researchers even doubt whether 1SWASP J1621 and V364 Lib have the same nature as normal dwarf novae. We studied the peculiar outbursts in these three objects via our optical photometry and spectroscopy, and performed numerical modeling of their orbital variations to investigate their properties. We found that their outbursts lasted for a long interval (a few tens of days), and that slow rises in brightness were commonly observed during the early stage of their outbursts. Our analyses and numerical modeling suggest that 1SWASP J1621 has a very high inclination, close to 90 deg, plus a faint hot spot. Although BD Pav seems to have a slightly lower inclination (\sim75 deg), the other properties are similar to those in 1SWASP J1621. On the other hand, V364 Lib appears to have a massive white dwarf, a hot companion star, and a low inclination (\sim35 deg). In addition, these three objects possibly have low transfer rate and/or large disks originating from the long orbital periods. We find that these properties of the three objects can explain their infrequent and low-amplitude outbursts within the context of the disk instability model in normal dwarf novae without strong magnetic field. In addition, we suggest that the highly-ionized emission lines in outburst are observed due to a high inclination and/or a massive white dwarf. More instances of this class of object may be unrecognized, since their unremarkable outbursts can be easily overlooked.Comment: 17 pages, 18 figures, 2 tables with supporting information. Accepted for publication in PAS

    Relationship between climatic conditions and the relative abundance of modern C<inf>3</inf> and C<inf>4</inf> plants in three regions around the North Pacific

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    Using -24‰ and -14‰ as the endpoints of stable carbon isotopic composition of total organic carbon (δ13CTOC) of surface soil under pure C3 and C4 vegetation, and surface soil δ13CTOC data from eastern China, Australia and the Great Plains of North America, we estimate the relative abundance of C3/C4 plants (i. e., the ratio of C3 or C4 biomass to local primary production) in modern vegetation for each region. The relative abundance of modern C3/C4 vegetation from each region is compared to the corresponding climatic parameters (mean annual temperature and precipitation) to explore the relationship between relative C4 abundance and climate. The results indicate that temperature controls the growth of C4 plants. However, even where temperature is high enough for the growth of C4 plants, they will only dominate the landscape when precipitation declines as temperatures increase. Our results are consistent with those of other investigations of the geographic distribution of modern C4 plant species. Therefore, our results provide an important reference for interpretation of past C3/C4 relative abundance records in these three regions. © 2010 Science China Press and Springer-Verlag Berlin Heidelberg

    Who's Getting a Head Start?:Mesocephalic Dogs in Still Images Are Attributed More Positively Valenced Emotions Than Dogs of Other Cephalic Index Groups

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    SIMPLE SUMMARY: Elements of a dog’s appearance in still images affect how positively human observers interpret that individual’s personality. Given that this may influence caregiving and other aspects of dog ownership, it is important to examine this phenomenon to protect dog welfare. Recently, the popularity of brachycephalic (short-muzzled) dogs has sharply risen and with it the need to assess whether this conformation affects the way in which human observers assign emotional attributes to dogs. The current study aimed to investigate whether cephalic index, a measure to quantify how long and wide a skull is, is related to how both dog owners and non-dog owning adults in the U.K. attribute emotions to still images of dogs, and in the case of dog owners, to their own dogs. Responses were received from 2451 participants. Images of breeds with less extreme skull shapes were most frequently assigned the strongest positive emotional attributions, and the inverse effect was found in more extreme skull shape categories. Results imply that the head shape of dogs may predispose humans to label those dogs with certain emotions, which could impact their behaviour towards those dogs and thus, the dogs’ welfare. These findings should prompt further investigation of morphological influences on dog–owner relationships and dog welfare. ABSTRACT: Assumptions about dogs’ personality are influenced by their appearance, which may lead to differences in ownership styles and subsequent canine welfare. The influence of canine appearance on observers’ emotion attributions to dogs remains largely unexplored. This study investigated whether canine head shape is related to how both dog owners and non-dog owning adults in the U.K. attribute emotions to still images of dogs, and in the case of dog owners, to their own dogs. Attachment, respondent personality and dog trainability were assessed as potential influences on emotional attribution in owners. Overall, 2451 participant responses were received. Still images of mesocephalic dogs were attributed primary and positively valenced emotion with more strength and frequency than other groups. Mesocephalic images were also attributed negatively valenced emotions less frequently and with less strength than other groups. Apart from empathy, no significant differences were found in emotional attribution to owned dogs of different head shapes; however, human personality influenced attribution of emotions to owned dogs. The finding that some dogs are attributed emotions more readily based on their appearance alone has applied importance, given, for example, the potential for misattribution of positive emotions to dogs in negative emotional states, and potential prejudice against dogs considered in negative emotional states

    Malta : language, literacy and identity in a Mediterranean island society

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    Available documentation for the early modern period indicates that the Malta harbor towns achieved literacy earlier than the countryside. The Maltese townsmen lived on a trading route, and it was necessary for them to learn the lingua franca, as the language of trade in the Mediterranean. The educated elite were able to acquire fluent speaking knowledge, as well as the ability to write, Tuscan (a dialect then in the process of becoming standard Italian), while continuing to employ their local Maltese ‘dialect’ on numerous occasions. By and large, the erosion of the position of Maltese as the subordinate language was an inevitable by-product of this development. The Maltese language was able to attain the function of a literary language in the nineteenth century but it had no standard orthography until 1931 and was only adopted as Malta’s official language in 1964.peer-reviewe

    The `Parahippocampal Place Area' Responds Selectively to High Spatial Frequencies

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    Defining the exact mechanisms by which the brain processes visual objects and scenes remains an unresolved challenge. Valuable clues to this process have emerged from the demonstration that clusters of neurons (“modules”) in inferior temporal cortex apparently respond selectively to specific categories of visual stimuli, such as places/scenes. However, the higher-order “category-selective” response could also reflect specific lower-level spatial factors. Here we tested this idea in multiple functional MRI experiments, in humans and macaque monkeys, by systematically manipulating the spatial content of geometrical shapes and natural images. These tests revealed that visual spatial discontinuities (as reflected by an increased response to high spatial frequencies) selectively activate a well-known place-selective region of visual cortex (the “parahippocampal place area”) in humans. In macaques, we demonstrate a homologous cortical area, and show that it also responds selectively to higher spatial frequencies. The parahippocampal place area may use such information for detecting object borders and scene details during spatial perception and navigation.National Institutes of Health (U.S.) (NIH Grant R01 MH6752)National Institutes of Health (U.S.) (grant R01 EY017081)Athinoula A. Martinos Center for Biomedical ImagingNational Center for Research Resources (U.S.)Mind Research Institut

    Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

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    Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication
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