884 research outputs found

    The United States and the Independence of Buenos Aires

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    Prior to the era of revolution the people and the government of the United States came into contact chiefly with the border regions of Spain\u27s American empire. Such areas as Florida, Texas, and the Greater Antilles were absorbing the attention of American expansionists. Thus, not only by action but by basic policy, the United Stateswas opposed to contributing to the independence of Buenos Aires.https://scholars.fhsu.edu/fort_hays_studies_series/1036/thumbnail.jp

    MG1-688432: A Peculiar Variable System

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    The short period variable star MG1-688432 has been discovered to exhibit occasional extremely high energy optical outbursts as high as 10^31 joules. Outbursts are typically of several hours duration. These events are often highly structured, resembling sequential associated releases of energy. Twenty years of time sequence photometry is presented, indicating a basic sinusoidal light curve of mean period 6.65d, with some phase shifting and long-term temporal trends in amplitude and mean brightness. Spectroscopy reveals a peculiar star, best resembling a K3 subgiant that has evolved off the main sequence moderately red-ward of the giant branch. Spectroscopic and radial velocity analyses indicate a binary system orbiting its barycenter with an unseen companion to the K3IV primary. This is not an eclipsing system with the inclination of the orbit precluding eclipse by the secondary. The system is at a distance of 1.5kpc and analysis of GAIA observations leads to the conclusion that the HR diagram position of MG1-688432 is established by an intrinsic feature of the system, most likely either the stellar evolutionary state of the observed star or the presence of small (non-gray) dust within the system. Two mechanisms that might give rise to the system are 1) impacts with tidally disrupted planetary debris, and 2) magnetically induced chromospheric activity. An intriguing idea that requires further investigation suggests that the unseen companion is perhaps a white dwarf star which has encountered a planet and tidally shredded it to produce a debris and dust veil that modulates the brightness of the primary.Comment: 74 pages, 36 figures, submitted to Astrophysical Journal Supplemen

    A stepped wedge cluster randomized control trial of dried blood spot testing to improve the uptake of hepatitis C antibody testing within UK prisons

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    Background: The prevalence of hepatitis C (HCV) is elevated within prison populations, yet diagnosis in prisons remains low. Dried blood spot testing (DBST) is a simple procedure for the detection of HCV antibodies; its impact on testing in the prison context is unknown. Methods: We carried out a stepped-wedge cluster-randomized control trial of DBST for HCV among prisoners within five male prisons and one female prison. Each prison was a separate cluster. The order in which the intervention (training in use of DBST for HCV testing and logistic support) was introduced was randomized across clusters. The outcome measure was the HCV testing rate by prison. Imputation analysis was carried out to account for missing data. Planned and actual intervention times differed in some prisons; data were thus analysed by intention to treat (ITT) and by observed step times. Results: There was insufficient evidence of an effect of the intervention on testing rate using either the ITT intervention time (OR: 0.84; 95% CI: 0.68�1.03; P = 0.088) or using the actual intervention time (OR: 0.86; 95% CI: 0.71�1.06; P = 0.153). This was confirmed by the pooled results of five imputed data sets. Conclusions: DBST as a stand-alone intervention was insufficient to increase HCV diagnosis within the UK prison setting. Factors such as staff training and allocation of staff time for regular clinics are key to improving service delivery. We demonstrate that prisons can conduct rigorous studies of new interventions, but data collection can be problematic. Trial registration: International Standard Randomized Controlled Trial Number Register (ISRCTN number ISRCTN05628482)

    Evolutionary relationships in Panicoid grasses based on plastome phylogenomics (Panicoideae; Poaceae)

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    Background: Panicoideae are the second largest subfamily in Poaceae (grass family), with 212 genera and approximately 3316 species. Previous studies have begun to reveal relationships within the subfamily, but largely lack resolution and/or robust support for certain tribal and subtribal groups. This study aims to resolve these relationships, as well as characterize a putative mitochondrial insert in one linage. Results: 35 newly sequenced Panicoideae plastomes were combined in a phylogenomic study with 37 other species: 15 Panicoideae and 22 from outgroups. A robust Panicoideae topology largely congruent with previous studies was obtained, but with some incongruences with previously reported subtribal relationships. A mitochondrial DNA (mtDNA) to plastid DNA (ptDNA) transfer was discovered in the Paspalum lineage. Conclusions: The phylogenomic analysis returned a topology that largely supports previous studies. Five previously recognized subtribes appear on the topology to be non-monophyletic. Additionally, evidence for mtDNA to ptDNA transfer was identified in both Paspalum fimbriatum and P. dilatatum, and suggests a single rare event that took place in a common progenitor. Finally, the framework from this study can guide larger whole plastome sampling to discern the relationships in Cyperochloeae, Steyermarkochloeae, Gynerieae, and other incertae sedis taxa that are weakly supported or unresolved.Fil: Burke, Sean V.. Northern Illinois University; Estados UnidosFil: Wysocki, William P.. Northern Illinois University; Estados UnidosFil: Zuloaga, Fernando Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; ArgentinaFil: Craine, Joseph M.. Jonah Ventures; Estados UnidosFil: Pires, J. Chris. University of Missouri; Estados UnidosFil: Edger, Patrick P.. Michigan State University; Estados UnidosFil: Mayfield Jones, Dustin. Donald Danforth Plant Science Center; Estados UnidosFil: Clark, Lynn G.. Iowa State University; Estados UnidosFil: Kelchner, Scot A.. University of Idaho; Estados UnidosFil: Duvall, Melvin R.. Northern Illinois University; Estados Unido

    Correlated variability in the blazar 3C 454.3

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    The blazar 3C 454.3 was revealed by the Fermi Gamma-ray Space Telescope to be in an exceptionally high flux state in July 2008. Accordingly, we performed a multi-wavelength monitoring campaign on this blazar using IR and optical observations from the SMARTS telescopes, optical, UV and X-ray data from the Swift satellite, and public-release gamma-ray data from Fermi. We find an excellent correlation between the IR, optical, UV and gamma-ray light curves, with a time lag of less than one day. The amplitude of the infrared variability is comparable to that in gamma-rays, and larger than at optical or UV wavelengths. The X-ray flux is not strongly correlated with either the gamma-rays or longer wavelength data. These variability characteristics find a natural explanation in the external Compton model, in which electrons with Lorentz factor gamma~10^(3-4) radiate synchrotron emission in the infrared-optical and also scatter accretion disk or emission line photons to gamma-ray energies, while much cooler electrons (gamma~10^(1-2)) produce X-rays by scattering synchrotron or other ambient photons.Comment: 7 pages, 3 figures, submitted to ApJ Letter

    Measuring the spin of the primary black hole in OJ287

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    The compact binary system in OJ287 is modelled to contain a spinning primary black hole with an accretion disk and a non-spinning secondary black hole. Using Post Newtonian (PN) accurate equations that include 2.5PN accurate non-spinning contributions, the leading order general relativistic and classical spin-orbit terms, the orbit of the binary black hole in OJ287 is calculated and as expected it depends on the spin of the primary black hole. Using the orbital solution, the specific times when the orbit of the secondary crosses the accretion disk of the primary are evaluated such that the record of observed outbursts from 1913 up to 2007 is reproduced. The timings of the outbursts are quite sensitive to the spin value. In order to reproduce all the known outbursts, including a newly discovered one in 1957, the Kerr parameter of the primary has to be 0.28±0.080.28 \pm 0.08. The quadrupole-moment contributions to the equations of motion allow us to constrain the `no-hair' parameter to be 1.0±0.31.0\:\pm\:0.3 where 0.3 is the one sigma error. This supports the `black hole no-hair theorem' within the achievable precision. It should be possible to test the present estimate in 2015 when the next outburst is due. The timing of the 2015 outburst is a strong function of the spin: if the spin is 0.36 of the maximal value allowed in general relativity, the outburst begins in early November 2015, while the same event starts in the end of January 2016 if the spin is 0.2Comment: 12 pages, 6 figure

    Intervention Now to Eliminate Repeat Unintended Pregnancy in Teenagers (INTERUPT): a systematic review of intervention effectiveness and cost-effectiveness, and qualitative and realist synthesis of implementation factors and user engagement.

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    BACKGROUND: Unintended repeat conceptions can result in emotional, psychological and educational harm to young women, often with enduring implications for their life chances. This study aimed to identify which young women are at the greatest risk of repeat unintended pregnancies; which interventions are effective and cost-effective; and what are the barriers to and facilitators for the uptake of these interventions. METHODS: We conducted a mixed-methods systematic review which included meta-analysis, framework synthesis and application of realist principles, with stakeholder input and service user feedback to address this. We searched 20 electronic databases, including MEDLINE, Excerpta Medica database, Applied Social Sciences Index and Abstracts and Research Papers in Economics, to cover a broad range of health, social science, health economics and grey literature sources. Searches were conducted between May 2013 and June 2014 and updated in August 2015. RESULTS: Twelve randomised controlled trials (RCTs), two quasi-RCTs, 10 qualitative studies and 53 other quantitative studies were identified. The RCTs evaluated psychosocial interventions and an emergency contraception programme. The primary outcome was repeat conception rate: the event rate was 132 of 308 (43%) in the intervention group versus 140 of 289 (48%) for the control group, with a non-significant risk ratio (RR) of 0.92 [95% confidence interval (CI) 0.78-1.08]. Four studies reported subsequent birth rates: 29 of 237 (12%) events for the intervention arm versus 46 out of 224 (21%) for the control arm, with an RR of 0.60 (95% CI 0.39-0.93). Many repeat conceptions occurred in the context of poverty, low expectations and aspirations and negligible opportunities. Qualitative and realist evidence highlighted the importance of context, motivation, future planning and giving young women a central and active role in the development of new interventions. CONCLUSIONS: Little or no evidence for the effectiveness or cost-effectiveness of any of the interventions to reduce repeat pregnancy in young women was found. Qualitative and realist evidence helped to explain gaps in intervention design that should be addressed. More theory-based, rigorously evaluated programmes need to be developed to reduce unintended repeat pregnancy in young women. TRIAL REGISTRATION: PROSPERO, CRD42012003168 . Cochrane registration number: i = fertility/0068

    The Mass-Radius(-Rotation?) Relation for Low-Mass Stars

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    The fundamental properties of low-mass stars are not as well understood as those of their more massive counterparts. The best method for constraining these properties, especially masses and radii, is to study eclipsing binary systems, but only a small number of late-type (M0 or later) systems have been identified and well-characterized to date. We present the discovery and characterization of six new M dwarf eclipsing binary systems. The twelve stars in these eclipsing systems have masses spanning 0.38-0.59 Msun and orbital periods of 0.6--1.7 days, with typical uncertainties of ~0.3% in mass and 0.5--2.0% in radius. Combined with six known systems with high-precision measurements, our results reveal an intriguing trend in the low-mass regime. For stars with M=0.35-0.80 Msun, components in short-period binary systems (P<1 day; 12 stars) have radii which are inflated by up to 10% (mean=4.8+/-1.0%) with respect to evolutionary models for low-mass main-sequence stars, whereas components in longer-period systems (>1.5 days; 12 stars) tend to have smaller radii (mean=1.7+/-0.7%). This trend supports the hypothesis that short-period systems are inflated by the influence of the close companion, most likely because they are tidally locked into very high rotation speeds that enhance activity and inhibit convection. In summary, very close binary systems are not representative of typical M dwarfs, but our results for longer-period systems indicate that the evolutionary models are broadly valid in the M~0.35-0.80 Msun regime.Comment: Accepted to ApJ; 21 pages, 10 figures, 8 tables in emulateapj format. The full contents of Table 4 are included in the submission as tab4.tx

    Intervention Now To Eliminate Repeat Unintended Pregnancy in Teenagers (INTERUPT): a systematic review of intervention effectiveness and cost-effectiveness, qualitative and realist synthesis of implementation factors and user engagement

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    Background The UK has the highest rate of teenage pregnancies in Western Europe, a fifth are repeat pregnancies. Unintended conceptions can result in emotional, psychological and educational harm to teenage girls, often with enduring implications for their life chances. Babies of teenage mothers have increased mortality in their first year and increased risk of poverty, educational underachievement and unemployment later in life, with associated societal costs. Methods and analysis We will conduct a streamed, mixed-methods systematic review to find and evaluate interventions designed to reduce repeat unintended teen pregnancies. Our aims are to identify Who is at greater risk of repeat unintended pregnancies? Which interventions are effective, cost-effective, how they work, in what setting and for whom? What are the barriers and facilitators to intervention uptake? Traditional electronic database searches will be augmented by targeted searches for evidence ‘clusters’ and guided by an advisory group of experts and stakeholders. To address the topic's inherent complexities, we will use a highly structured, innovative and iterative approach combining methodological techniques tailored to each stream of evidence. Quantitative data will be synthesised with reference to Cochrane guidelines for public health interventions. Qualitative evidence addressing facilitators and barriers to the uptake of interventions, experience and acceptability of interventions will be synthesised thematically. We will apply the principles of realist synthesis to uncover theories and mechanisms underpinning interventions. We will conduct an integration and overarching narrative of findings authenticated by client group feedback. Ethics and dissemination We will publish the complete review in ‘Health Technology Assessment’ and sections in specialist peer-reviewed journals. We will present at national and international conferences in the fields of public health, reproductive medicine and review methodology. Findings will be fed back to service users and practitioners via workshops run by the partner collaborators
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