1,037 research outputs found

    The PL calibration for Milky Way Cepheids and its implications for the distance scale

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    The rationale behind recent calibrations of the Cepheid PL relation using the Wesenheit formulation is reviewed and reanalyzed, and it is shown that recent conclusions regarding a possible change in slope of the PL relation for short-period and long-period Cepheids are tied to a pathological distribution of HST calibrators within the instability strip. A recalibration of the period-luminosity relation is obtained using Galactic Cepheids in open clusters and groups, the resulting relationship, described by log L/L_sun = 2.415(+-0.035) + 1.148(+-0.044)log P, exhibiting only the moderate scatter expected from color spread within the instability strip. The relationship is confirmed by Cepheids with HST parallaxes, although without the need for Lutz-Kelker corrections, and in general by Cepheids with revised Hipparcos parallaxes, albeit with concerns about the cited precisions of the latter. A Wesenheit formulation of Wv = -2.259(+-0.083) - 4.185(+-0.103)log P for Galactic Cepheids is tested successfully using Cepheids in the inner regions of the galaxy NGC 4258, confirming the independent geometrical distance established for the galaxy from OH masers. Differences between the extinction properties of interstellar and extragalactic dust may yet play an important role in the further calibration of the Cepheid PL relation and its application to the extragalactic distance scale.Comment: Accepted for Publication (Astrophysics & Space Science

    Endothelin-Converting Enzyme-1 (ECE-1) Is Post-Transcriptionally Regulated by Alternative Polyadenylation

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    Endothelin-converting enzyme-1 (ECE-1) is the enzyme predominantly responsible for producing active endothelin-1 (ET-1), a mitogenic peptide implicated in the aetiology of a number of diseases, including cancer. Elevated levels of ECE-1 have been observed in a range of malignancies, with high expression conferring poor prognosis and aiding the acquisition of androgen independence in prostate cancer. The mechanisms regulating the expression of ECE-1 in cancer cells are poorly understood, hampering the development of novel therapies targeting the endothelin axis. Here we provide evidence that the expression of ECE-1 is markedly inhibited by its 3′UTR, and that alternative polyadenylation (APA) results in the production of ECE-1 transcripts with truncated 3′UTRs which promote elevated protein expression. Abolition of the ECE-1 APA sites reduced protein expression from a reporter vector in prostate cancer cells, suggesting these sites are functional. This is the first study to identify ECE-1 as a target for APA, a regulatory mechanism aberrantly activated in cancer cells, and provides novel information about the mechanisms leading to ECE-1 overexpression in malignant cells

    Revealing the level of tension between cultural heritage and development in World Heritage cities

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    In theory, cultural heritage is regarded as a useful catalyst for sustainable development. However, in reality it is also regarded as an obstacle. Although cultural heritage is widely recognized as a unique and valuable resource of economic development, local governments often favor development over the protection of cultural heritage. World Heritage cities (i.e. all urban settlements with properties inscribed on the World Heritage List, located in or at the outskirts of their urban areas) contain cultural heritage that is not only of local importance, but is also of outstanding universal value (OUV) – that is, of global importance. Such heritage can enrich cultural diversity of urban settlements, but can also provide a source of tension for the comprehensive management of varied urban landscapes. Three international organizations have been found periodically and systematically inventorying endangered cultural heritage properties throughout the world: UNESCO with the List of World Heritage in Danger, ICO-MOS with Heritage at Risk, and the World Monuments Fund with the World Monuments Watch. Properties identified by these organizations are considered to be at risk as a result of varied threats, including development. However, the processes and criteria used by these organizations to determine such dangers were found to be very distinctive and inconsistent. The goal of this paper is to propose systematic and comprehensive criteria with which to categorize the endan-gered level of World Heritage cities – specifically those threatened by development – and to present the resultant ranking of these cities by such criteria. All official documents publishing the decisions adopted during the Ses-sions of the WH Committee, from 1977 to 2009, shall be used as a data source. This quantitative analysis will help evidence the evolution of World Heritage cities threatened by development, as well as the related trends of threats, causes and impacts. Initial analysis of the data has shown that many more WH cities (as defined above) have been endangered than have been represented on the List of World Heritage in Danger. While only 21 of the 476 WH properties includ-ing or included in WH cities have been included on the List in Danger, 193 have been discussed as endangered (to varying degrees) during WH Committee Sessions. Most frequently, the threats discussed had the potential to – but did not yet – cause irreversible damage to the OUV. However, many of the threats did cause damage to the OUV, though not to the extent necessary to warrant inclusion on the List in Danger. The primary threats mentioned in Committee Sessions have been new development (mostly commercial and residential) and infrastructure construction (such as roads, airports, ports and sewage systems). The primary causes of these threats have been insufficient implementation of regulatory frameworks (such as management plans, zoning laws and conservation plans), insufficient buffer zones, and insufficient coordination of stakehold-ers. While other threats, such as looting, flawed restoration work and general neglect have been mentioned; new development and construction are by far the most cited threats to OUV. This initial analysis illustrates the alarming tensions between heritage preservation, modernization and growth in WH cities throughout the world. This data is only the tip of the iceberg. Based mainly on official documents from World Heritage Committee Meeting Sessions, the data reflects only those cities and threats that capture the attention of the Committee. There are likely many more WH cities endangered than the Committee has the time to consider during its annual Sessions. Furthermore, the lack of specific references to development-related threats in all cities does not mean that they do not exist. Just as the operational guidelines have evolved, it is expected that the detail of information concerning threats, causes and impacts, will also increase in time. This research is considered to be a step forward in understanding development as a danger to World Heritage cities, including its threats, causes and impact. Moreover, as part of a broader international research entitled, Outstanding Universal Value, World Heritage Cities and Sustainability, the results will also help to determine best practices among the OUV assessment practices followed to protect World Heritage cities

    The Tensor to Scalar Ratio of Phantom Dark Energy Models

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    We investigate the anisotropies in the cosmic microwave background in a class of models which possess a positive cosmic energy density but negative pressure, with a constant equation of state w = p/rho < -1. We calculate the temperature and polarization anisotropy spectra for both scalar and tensor perturbations by modifying the publicly available code CMBfast. For a constant initial curvature perturbation or tensor normalization, we have calculated the final anisotropy spectra as a function of the dark energy density and equation of state w and of the scalar and tensor spectral indices. This allows us to calculate the dependence of the tensor-to-scalar ratio on w in a model with phantom dark energy, which may be important for interpreting any future detection of long-wavelength gravitational waves.Comment: 5 pages, 4 figure

    On the degree of scale invariance of inflationary perturbations

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    Many, if not most, inflationary models predict the power-law index of the spectrum of density perturbations is close to one, though not precisely equal to one, |n-1| \sim O(0.1), implying that the spectrum of density perturbations is nearly, but not exactly, scale invariant. Some models allow n to be significantly less than one (n \sim 0.7); a spectral index significantly greater than one is more difficult to achieve. We show that n \approx 1 is a consequence of the slow-roll conditions for inflation and ``naturalness,'' and thus is a generic prediction of inflation. We discuss what is required to deviate significantly from scale invariance, and then show, by explicit construction, the existence of smooth potentials that satisfy all the conditions for successful inflation and give nn as large as 2.Comment: 7 pages, 2 figures, submitted to Phys. Rev.

    The physiological effects of elevated intra-abdominal pressure following aneurysm repair

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    AbstractObjectives: elevated intra-abdominal pressure (IAP) may cause widespread organ dysfunction (abdominal compartment syndrome) through effects on the respiratory, cardiac, renal and gastro-intestinal systems. The aim of this study was to document IAP following aneurysm surgery, and to determine the effect of IAH on outcome. Design: prospective observational study. Setting: University Hospital. Subjects: the patient cohort comprised 75 patients undergoing infra-renal aneurysm repair (53 non-ruptured [40 conventional - 1 death, 13 endovascular] and 22 conventionally repaired ruptured AAA - 8 deaths). IAP was quantified by bladder manometry at the termination of the procedure and at 24 h intervals in patients who remained intubated. Physiological indices of organ function were recorded. Statistical analysis utilized the unpaired t-test, Fischer's exact test and Pearson's correlation. Results: IAP was significantly higher at abdominal closure following ruptured aneurysm repair (15.4 mmHg [SE 1.6]) than conventional (10.5 [0.89]) or endovascular elective repair (6.4 [1.0]) of non-ruptured AAA. The sensitivity and specificity of IAP to predict subsequent mortality was analysed using a receiver characteristic operating curve. This analysis demonstrated that a cut off of 15 mmHg was the most useful for indicating patients at risk (sensitivity 0.66, specificity 0.79). Physiological indices of organ dysfunction (pH[p = 0.027], base excess [p = 0.005], peak inspiratory pressure [p = 0.0015], CVP and urine output [p = 0.0029]) were significantly impaired in patients with IAP ≥ 15 mmHg, in comparison to patients with lower pressures. IAP correlated significantly with indices of cardiac (CVP p = 0.038), respiratory (PaO2/FiO2, p = 0.026), and renal function (urine output p = 0.046). Conclusions: these data suggest that the management of IAH may have a role following repair of ruptured AAA. High intra-abdominal pressures rarely complicate elective or endovascular aneurysm repair.Eur J Vasc Endovasc Surg 26, 293-298 (2003

    Limits on the gravity wave contribution to microwave anisotropies

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    We present limits on the fraction of large angle microwave anisotropies which could come from tensor perturbations. We use the COBE results as well as smaller scale CMB observations, measurements of galaxy correlations, abundances of galaxy clusters, and Lyman alpha absorption cloud statistics. Our aim is to provide conservative limits on the tensor-to-scalar ratio for standard inflationary models. For power-law inflation, for example, we find T/S<0.52 at 95% confidence, with a similar constraint for phi^p potentials. However, for models with tensor amplitude unrelated to the scalar spectral index it is still currently possible to have T/S>1.Comment: 23 pages, 7 figures, accepted for publication in Phys. Rev. D. Calculations extended to blue spectral index, Fig. 6 added, discussion of results expande

    The Detectability of Departures from the Inflationary Consistency Equation

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    We study the detectability, given CMB polarization maps, of departures from the inflationary consistency equation, r \equiv T/S \simeq -5 n_T, where T and S are the tensor and scalar contributions to the quadrupole variance, respectively. The consistency equation holds if inflation is driven by a slowly-rolling scalar field. Departures can be caused by: 1) higher-order terms in the expansion in slow-roll parameters, 2) quantum loop corrections or 3) multiple fields. Higher-order corrections in the first two slow-roll parameters are undetectably small. Loop corrections are detectable if they are nearly maximal and r \ga 0.1. Large departures (|\Delta n_T| \ga 0.1) can be seen if r \ga 0.001. High angular resolution can be important for detecting non-zero r+5n_T, even when not important for detecting non-zero r.Comment: 7 pages, 4 figures, submitted to PR

    The isolation of Leptospira interrogans serovar pomona and related serological findings associated with a mixed farming unit in the Transvaal

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    This is the first known isolation in the Republic of South Africa (RSA) of the serovar pomona from the organs of porcine foetuses as well as from the renal lymphnodes of slaughter pigs showing chronic nephritis. In addition, the serovar pomona was isolated from the kidneys of 87,5 % of the slaughter pigs examined. The success of these isolations was attributed in part to the refining of 2 existing isolation techniques which complement each other. Using the microscopic agglutination test, serum samples taken from the same farming unit showed evidence of antibodies to the serovar pomona in 89 out of the 170 bovines (52 %), 9 out of the 52 porcines (17 %), 2 of the 2 canines (100 %), 5 out of the 13 equines (38 %) and 2 out of the 152 ovines (1 %) that were tested. As far as is known, serological evidence of the serovar pomona in porcines, ovines, equines and canines has never previously been published in the RSA.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.lmchunu2014mn201

    The role of psychological flexibility in appearance anxiety in people who have experienced a visible burn injury

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    Background Individuals with visible differences can experience appearance anxiety that is distressing and disruptive to daily functioning. Understanding psychological factors that maintain appearance anxiety related to scarring is important in developing theoretical understanding of adjustment to injury, and in identifying targets for psychological therapies. This study aimed to investigate whether psychological flexibility, a key element underpinning acceptance and commitment therapy (ACT), was associated with appearance anxiety. It was hypothesised that reduced psychological flexibility (lower acceptance, cognitive defusion, mindfulness, and committed action) would be related to increased appearance anxiety. The role of psychological flexibility in the maintenance of appearance anxiety was investigated using a cross-sectional quantitative questionnaire study. Method Seventy-eight burns patients (47 female, 31 male; M age = 45.2 years) completed the Derriford Appearance Scale (DAS-24), the Acceptance and Action Questionnaire (AAQ-II), the Cognitive Fusion Questionnaire (CFQ), the Five Facet Mindfulness Questionnaire (FFMQ), and the Committed Action Questionnaire (CAQ-8). Results As hypothesised, increased appearance anxiety was related to reduced acceptance (rs(76) = 0.80, p < 0.001, one-tailed) and cognitive defusion (rs(76) = 0.76, p < 0.001). Reduced levels of mindfully describing (r(72) = −0.39, p < 0.001), acting with awareness (r(72) = −0.57, p < 0.001), non-judging (r(72) = −0.61, p < 0.001) and non-reactivity (r(72) = −0.28, p < 0.01) as well as reduced committed action (r(72) = −0.57, p < 0.001) were also related to increased appearance anxiety. Conclusions Individuals experiencing appearance anxiety associated with a burn injury may struggle with accepting difficult emotions, stepping back from distressing thoughts, being mindful and engaging in valued action. These findings suggest that ACT may be useful in treating appearance related anxiety and concerns associated with conditions causing a visible difference
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