448 research outputs found

    A compact star rotating at 1122 Hz and the r-mode instability

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    We show that r-mode instabilities severely constraint the composition of a compact star rotating at a submillisecond period. In particular, the only viable astrophysical scenario for such an object, present inside the Low Mass X-ray Binary associated with the x-ray transient XTE J1739-285, is that it has a strangeness content. Since previous analysis indicate that hyperonic stars or stars containing a kaon condensate are not good candidates, the only remaining possibility is that such an object is either a strange quark star or a hybrid quark-hadron star. We also discuss under which conditions sub-millisecond pulsars are rare.Comment: 13 pages, 4 figures, I table. Revised version contains a much more extended discussion of the astrophysical scenari

    Mutt & Jeff Divorced

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    Cartoon style illustration of two men with mustaches. One is wearing a top hat while the other is wearing a fedora.https://scholarsjunction.msstate.edu/cht-sheet-music/1433/thumbnail.jp

    Metropolitan Social Environments and Pre-HAART/HAART Era Changes in Mortality Rates (per 10,000 Adult Residents) among Injection Drug Users Living with AIDS

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    Background Among the largest US metropolitan areas, trends in mortality rates for injection drug users (IDUs) with AIDS vary substantially. Ecosocial, risk environment and dialectical theories suggest many metropolitan areas characteristics that might drive this variation. We assess metropolitan area characteristics associated with decline in mortality rates among IDUs living with AIDS (per 10,000 adult MSA residents) after highly active antiretroviral therapy (HAART) was developed. Methods This is an ecological cohort study of 86 large US metropolitan areas from 1993–2006. The proportional rate of decline in mortality among IDUs diagnosed with AIDS (as a proportion of adult residents) from 1993–1995 to 2004–2006 was the outcome of interest. This rate of decline was modeled as a function of MSA-level variables suggested by ecosocial, risk environment and dialectical theories. In multiple regression analyses, we used 1993–1995 mortality rates to (partially) control for pre-HAART epidemic history and study how other independent variables affected the outcomes. Results In multivariable models, pre-HAART to HAART era increases in ‘hard drug’ arrest rates and higher pre-HAART income inequality were associated with lower relative declines in mortality rates. Pre-HAART per capita health expenditure and drug abuse treatment rates, and pre- to HAART-era increases in HIV counseling and testing rates, were weakly associated with greater decline in AIDS mortality. Conclusions Mortality among IDUs living with AIDS might be decreased by reducing metropolitan income inequality, increasing public health expenditures, and perhaps increasing drug abuse treatment and HIV testing services. Given prior evidence that drug-related arrest rates are associated with higher HIV prevalence rates among IDUs and do not seem to decrease IDU population prevalence, changes in laws and policing practices to reduce such arrests while still protecting public order should be considered

    Public engagement with marine climate change issues: (Re)framings, understandings and responses

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    Climate change impacts on marine environments have been somewhat neglected in climate change research, particularly with regard to their social dimensions and implications. This paper contributes to addressing this gap through presenting a UK focused mixed-method study of how publics frame, understand and respond to marine climate change-related issues. It draws on data from a large national survey of UK publics (N = 1,001), undertaken in January 2011 as part of a wider European survey, in conjunction with in-depth qualitative insights from a citizens’ panel with participants from the East Anglia region, UK. This reveals that discrete marine climate change impacts, as often framed in technical or institutional terms, were not the most immediate or significant issues for most respondents. Study participants tended to view these climate impacts ‘in context’, in situated ways, and as entangled with other issues relating to marine environments and their everyday lives. Whilst making connections with scientific knowledge on the subject, public understandings of marine climate impacts were mainly shaped by personal experience, the visibility and proximity of impacts, sense of personal risk and moral or equity-based arguments. In terms of responses, study participants prioritised climate change mitigation measures over adaptation, even in high-risk areas. We consider the implications of these insights for research and practices of public engagement on marine climate impacts specifically, and climate change more generally

    Genetic and environmental influences on Type A Behavior Pattern: Evidence from twins and their parents in the Netherlands Twin Register

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    OBJECTIVE: There is a dose-response positive relationship between type A behavior (TABP) and cardiovascular disease-related symptoms. Estimates of heritability for TABP from previous studies vary; this might be explained by limitations in the sizes and compositions of the samples. METHODS: This study combines a large sample size, twin and parental, data from males and females, two generations of young adults and older adults, and the use of structural equation modeling (SEM) and full information maximum likelihood (FIML) estimation. To assess TABP, the Jenkins Activity Survey (JAS) was collected from MZ and DZ twins and their parents (n = 1670 twin families). Structural equation modeling is used to evaluate and estimate the effects of additive and nonadditive genetic effects, nonshared environmental effects, and competitive sibling interaction. RESULTS: Forty-five percent of the variance in TABP was the result of genetic factors (28% were additive and 17% were nonadditive). The remaining 55% of the variance was explained by environmental factors not shared by the members of the same family. Competitive sibling interaction effects were not significant. There was no evidence of sex differences either in variances or means. CONCLUSION: Understanding the sources of variance on TABP is important for therapy and prevention. According to the present results, the relevant environmental factors for the development of TABP are not shared by the members of the same family. The genetic portion of the variance is also worth considering for therapeutic purposes. Although the genetic code cannot be altered, its effects on behavior may be modifiable through the treatment of the biological mediators. Copyright © 2006 by the American Psychosomatic Society

    Improvement of the efficacy of endodontic solvents by ultrasonic agitation

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    [Excerpt] The success rates of endodontic treatment can reach levels from 86% to 98% (Abitbol et al., 2003). However, apical periodontitis may still persist or develop after treatment due to various factors, namely coronal leakage, caries or fractures, thus enabling reinfection by microorganisms of the oral cavity or proliferation of microorganisms in persisting endodontic infections (Siqueira, 2001, Correia-Sousa et al., 2015, Melo et al., 2017). Endodontic retreatment aims to reduce the bacterial load to a level that enables periapical healing. Nevertheless, its outcome is poor – about 70.9–83% (Torabinejad et al., 2009, Ng et al., 2011). The cleanliness of root canals cannot be accurately assessed through conventional periapical radiography or magnifying devices, but residual gutta-percha is systematically found in micro-CT scans after retreatment (Oltra et al., 2017). Chloroform and xylene have been widely used as endodontic solvents but concerns about their toxicity and potential carcinogenic effect led to seeking alternatives (Tamse et al., 1986, Metzger et al., 2000, Vajrabhaya et al., 2004, Magalhaes et al., 2007). Essential oils, like eucalyptol or orange oil, are one of the most common alternative groups of solvents used to enhance the dissolution or softening of gutta-percha. However, although they are considered less toxic, they are also reported as less powerful (Zaccaro Scelza et al., 2006, Faria-Junior et al., 2011, Martos et al., 2011). Studies show that, despite all the currently available technology, it is still not possible to achieve the complete removal of the potentially infected filling materials, which prevents total debridement and effective bacteria control (Alves et al., 2016, Keles et al., 2016, Rossi-Fedele and Ahmed, 2017). Although solvents have been indicated to prevent complications, such as ledges or perforations, in retreatment procedures, the literature reports that their use may hinder the cleaning of the root canal (Horvath et al., 2009). Retreatment can be carried out with or without solvents, but professionals often prefer to remove gutta-percha mainly with instrumentation, even though this may be a longer and less predictable procedure (Sae-Lim et al., 2000, Khalilak et al., 2013). Thus, endodontic solvents have almost fallen out of use. A new insight on endodontic retreatment seems to be necessary. [...]- (undefined

    The structure of working memory and how it relates to intelligence in children

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    This study explored the structure of working memory, and its relationship with intelligence in 176 typically-developing children in the 4th and 5th grades at school. Different measures of working memory (WM), and intelligence (g) were administered. Confirmatory factor analyses showed that WM involves an attentional control system and storage aspects that rely on domain-specific verbal (STM-V) and visuospatial (STM-VS) resources. The structural equation models showed that WM predicts a large portion (66%) of the variance in g, confirming that the two constructs are separable but closely related in young children. Findings also showed that only WM and STM-VS are significantly related to g, while the contribution of STM-V is moderate. Theoretical implications for the relationship between WM and g are discussed
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