276 research outputs found
Neutron Star Radius-to-mass Ratio from Partial Accretion Disc Occultation as Measured through Fe K Line Profiles
We present a new method to measure the radius-to-mass ratio (R/M) of weakly
magnetic, disc-accreting neutron stars by exploiting the occultation of parts
of the inner disc by the star itself. This occultation imprints characteristic
features on the X-ray line profile that are unique and are expected to be
present in low mass X-ray binary systems seen under inclinations higher than
~65 degrees. We analyse a NuSTAR observation of a good candidate system, 4U
1636-53, and find that X-ray spectra from current instrumentation are unlikely
to single out the occultation features owing to insufficient signal-to-noise.
Based on an extensive set of simulations we show that large-area X-ray
detectors of the future generation could measure R/M to ~2{\div}3% precision
over a range of inclinations. Such is the precision in radius determination
required to derive tight constraints on the equation of state of ultradense
matter and it represents the goal that other methods too aim to achieve in the
future.Comment: 17 pages, 8 figures; this is a pre-print edition of an article that
has been accepted for publication in the Astrophysical Journa
CHM/REP1 Transcript Expression and Loss of Visual Function in Patients Affected by Choroideremia
PURPOSE. To evaluate the disease progression in patients with clinical and genetic diagnoses of choroideremia during a long-term follow-up and to investigate the relationship between pathogenic variants in the CHM/REP1 gene and disease phenotypes. METHODS. We performed a retrospective longitudinal study on 51 affected men by reviewing medical charts at baseline and follow-up visits to extract the following ocular findings: best-corrected visual acuity, Goldmann visual field, optical coherence tomography, microperimetry. Data obtained from the analysis of DNA and mRNA were reevaluated for genetic classification of patients. RESULTS. The longitudinal analysis showed a significant (P < 0.001) worsening of best-corrected visual acuity with a mean rate of 0.011 logMar per year before 50 years and 0.025 logMar per year after 50 years. Similarly, V4e Goldmann visual field area significantly (P ≤ 0.01) decreased at a mean rate of 2.7% per year before 40 years and 5.7% after 40 years. Moreover, we observed a significant (P < 0.05) decrease of macular sensitivity with a mean rate of 5.0% per year and a decrease of mean macular thickness with a mean rate of 0.8% per year. We classified our patients into two groups according to the expression of the CHM/ REP1 gene transcript and observed that mutations leading to mRNA absence are associated with an earlier best-corrected visual acuity and Goldmann visual field loss. CONCLUSIONS. Our analysis of morphological and functional parameters in choroideremia patients showed a slow disease progression, particularly in the first decades of life. Overall, reevaluation of clinical and molecular data suggests exploring the genotype–phenotype relationship based on CHM/REP1 transcript expression. PURPOSE. To evaluate the disease progression in patients with clinical and genetic diagnoses of choroideremia during a long-term follow-up and to investigate the relationship between pathogenic variants in the CHM/REP1 gene and disease phenotypes. METHODS. We performed a retrospective longitudinal study on 51 affected men by reviewing medical charts at baseline and follow-up visits to extract the following ocular findings: best-corrected visual acuity, Goldmann visual field, optical coherence tomography, microperimetry. Data obtained from the analysis of DNA and mRNA were reevaluated for genetic classification of patients. RESULTS. The longitudinal analysis showed a significant (P < 0.001) worsening of best-corrected visual acuity with a mean rate of 0.011 logMar per year before 50 years and 0.025 logMar per year after 50 years. Similarly, V4e Goldmann visual field area significantly (P ≤ 0.01) decreased at a mean rate of 2.7% per year before 40 years and 5.7% after 40 years. Moreover, we observed a significant (P < 0.05) decrease of macular sensitivity with a mean rate of 5.0% per year and a decrease of mean macular thickness with a mean rate of 0.8% per year. We classified our patients into two groups according to the expression of the CHM/ REP1 gene transcript and observed that mutations leading to mRNA absence are associated with an earlier best-corrected visual acuity and Goldmann visual field loss. CONCLUSIONS. Our analysis of morphological and functional parameters in choroideremia patients showed a slow disease progression, particularly in the first decades of life. Overall, reevaluation of clinical and molecular data suggests exploring the genotype–phenotype relationship based on CHM/REP1 transcript expression
Neutron star radius-To-mass ratio from partial accretion disk occultation as measured through fe kα line profiles
We present a new method to measure the radius-To-mass ratio (R/M) of weakly magnetic, disk-Accreting neutron stars by exploiting the occultation of parts of the inner disk by the star itself. This occultation imprints characteristic features on the X-ray line profile that are unique and are expected to be present in low-mass X-ray binary systems seen under inclinations higher than ∼65°. We analyze a Nuclear Spectroscopic Telescope Array observation of a good candidate system, 4U 1636-53, and find that X-ray spectra from current instrumentation are unlikely to single out the occultation features owing to insufficient signal-To-noise. Based on an extensive set of simulations we show that large-Area X-ray detectors of the future generation could measure R/M to ∼2 ÷ 3% precision over a range of inclinations. Such is the precision in radius determination required to derive tight constraints on the equation of state of ultradense matter and it represents the goal that other methods also aim to achieve in the future
Prenatal expression of d-aspartate oxidase causes early cerebral d-aspartate depletion and influences brain morphology and cognitive functions at adulthood
The free d-amino acid, d-aspartate, is abundant in the embryonic brain but significantly decreases after birth. Besides its intracellular occurrence, d-aspartate is also present at extracellular level and acts as an endogenous agonist for NMDA and mGlu5 receptors. These findings suggest that d-aspartate is a candidate signaling molecule involved in neural development, influencing brain morphology and behaviors at adulthood. To address this issue, we generated a knockin mouse model in which the enzyme regulating d-aspartate catabolism, d-aspartate oxidase (DDO), is expressed starting from the zygotic stage, to enable the removal of d-aspartate in prenatal and postnatal life. In line with our strategy, we found a severe depletion of cerebral d-aspartate levels (up to 95%), since the early stages of mouse prenatal life. Despite the loss of d-aspartate content, Ddo knockin mice are viable, fertile, and show normal gross brain morphology at adulthood. Interestingly, early d-aspartate depletion is associated with a selective increase in the number of parvalbumin-positive interneurons in the prefrontal cortex and also with improved memory performance in Ddo knockin mice. In conclusion, the present data indicate for the first time a biological significance of precocious d-aspartate in regulating mouse brain formation and function at adulthood
An Equifinality Energy Management Framework in Terms of Benchmarking Practices and Expectations: The EnerMan Project Outlook
Background: The Industry 4.0 wave is leading the changes in existing manufacturing and industrial processes across the world. This is especially important in the formulation of the smart-factory concept with an outlook to energy sustainable processes. In viewing and identifying the foundational elements of such a transformation, the initial conditions and current practices in a cross-sectoral manner is considered a first, yet crucial step in the EU-funded project EnerMan. Methods: In this paper, we identify and analyse the key common features and characteristics of industrial practices set in a perspective of similar and identical functions with a focus to three key energy areas: sustainability, management, and footprint. The examination of different industrial sector cases is performed via distributed questionnaires and then viewed under the prism of the equifinality state via a text-mining analysis approach. Results: identification of common themes and benchmarking of current practices in a cross-industry manner led to the creation of a common systemic framework within energy management related aspects, which is hereby presented. Conclusions: use of an equifinality approach in energy management practices should be further pursued to open up new methods of ideation and innovation and communicate systems’ design in tandem with each industrial set goals
Feasibility of a Stop Smoking Program for Healthcare Workers in an Italian Hospital: Econometric Analysis in a Total Worker Health® Approach
Background: Over 20% of healthcare workers (HCWs) are active smokers. Smoking is a targeted issue for workplace health promotion (WHP) programs. Objective: Our study aims to evaluate the effectiveness of the Stop Smoking Promotion (SSP) intervention, a 6-hour training course for HCWs, which took place from May 2018 to July 2019. Methods: We compared HCWs who successfully quit smoking (n = 15) to those who did not (n = 25) in terms of Sickness Absence Days (SADs). Moreover, we conducted an econometric analysis by calculating the return on investment and implementing a break-even analysis. Findings: Among the 40 enrolled workers, a success rate of 37.5% was observed after a span of over two years from the SSP intervention (with nurses and physicians showed the best success rate). Overall, participants showed a noticeable absenteeism reduction after the SSP intervention, with a reduction rate of 85.0% in a one-year period. The estimated ROI for the hospital was 1.90, and the break-even point was 7.85. In other words, the organization nearly doubled its profit from the investment, and the success of at least eight participants balanced costs and profits. Conclusion: Our pilot study confirms that WHP programs are simple and cost-saving tools which may help improve control over the smoking pandemic in healthcare settings
Effects of the dose of erythropoiesis stimulating agents on cardiovascular events, quality of life, and health-related costs in hemodialysis patients: the clinical evaluation of the dose of erythropoietins (C.E. DOSE) trial protocol
<p>Abstract</p> <p>Background</p> <p>Anemia is a risk factor for death, adverse cardiovascular outcomes and poor quality of life in patients with chronic kidney disease (CKD). Erythropoietin Stimulating Agents (ESA) are commonly used to increase hemoglobin levels in this population. In observational studies, higher hemoglobin levels (around 11-13 g/dL) are associated with improved survival and quality of life compared to hemoglobin levels around 9-10 g/dL. A systematic review of randomized trials found that targeting higher hemoglobin levels with ESA causes an increased risk of adverse vascular outcomes. It is possible, but has never been formally tested in a randomized trial, that ESA dose rather than targeted hemoglobin concentration itself mediates the increased risk of adverse vascular outcomes. The Clinical Evaluation of the DOSe of Erythropoietins (C.E. DOSE) trial will assess the benefits and harms of a high versus a low fixed ESA dose for the management of anemia in patients with end stage kidney disease.</p> <p>Methods/Design</p> <p>This is a randomized, prospective open label blinded end-point (PROBE) trial due to enrol 2204 hemodialysis patients in Italy. Patients will be randomized 1:1 to 4000 IU/week versus 18000 IU/week of intravenous epoietin alfa or beta, or any other ESA in equivalent doses. The dose will be adjusted only if hemoglobin levels fall outside the 9.5-12.5 g/dL range. The primary outcome will be a composite of all-cause mortality, non fatal stroke, non fatal myocardial infarction and hospitalization for cardiovascular causes. Quality of life and costs will also be assessed.</p> <p>Discussion</p> <p>The C.E.DOSE study will help inform the optimal therapeutic strategy for the management of anemia of hemodialysis patients, improving clinical outcomes, quality of life and costs, by ascertaining the potential benefits and harms of different fixed ESA doses.</p> <p>Trial registration</p> <p>Clinicaltrials.gov NCT00827021</p
Evidence of Asymmetry in SN 2007rt, a Type IIn Supernova
An optical photometric and spectroscopic analysis of the slowly-evolving Type
IIn SN2007rt is presented, covering a duration of 481 days after discovery. Its
earliest spectrum, taken approximately 100 days after the explosion epoch,
indicates the presence of a dense circumstellar medium, with which the
supernova ejecta is interacting. This is supported by the slowly-evolving light
curve. A notable feature in the spectrum of SN 2007rt is the presence of a
broad He I 5875 line, not usually detected in Type IIn supernovae. This may
imply that the progenitor star has a high He/H ratio, having shed a significant
portion of its hydrogen shell via mass-loss. An intermediate resolution
spectrum reveals a narrow Halpha P-Cygni profile, the absorption component of
which has a width of 128 km/s. This slow velocity suggests that the progenitor
of SN 2007rt recently underwent mass-loss with wind speeds comparable to the
lower limits of those detected in luminous blue variables. Asymmetries in the
line profiles of H and He at early phases bears some resemblance to
double-peaked features observed in a number of Ib/c spectra. These asymmetries
may be indicative of an asymmetric or bipolar outflow or alternatively dust
formation in the fast expanding ejecta. In addition, the late time spectrum, at
over 240 days post-explosion, shows clear evidence for the presence of newly
formed dust.Comment: Submitted to A&A on 4/2/2009. Accepted by A&A on 17/5/2009.15 pages
plus 3 pages of online materia
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