2,475 research outputs found
Transit Timing Variation Analysis of Ogle-Tr-132b with Seven New Transits
December 15, 2010We report the results of the first transit timing variation analysis of the very hot Jupiter OGLE-TR-132b, using 10 transits collected over a seven-year period. Our analysis combines three previously published transit light curves with seven new transits, which were observed between 2008 February and 2009 May with the new MagIC-e2V instrument on the Magellan Telescopes in Chile. We provide a revised planetary radius of R[subscript p] = 1.23 ± 0.07R[subscript J] , which is slightly larger, but consistent within the errors, than that given by previously published results. Analysis of the planet-to-star radius ratio, orbital separation, inclination, and transit duration reveals no apparent variation in any of those parameters during the time span observed. We also find no sign of transit timing variations larger than –108 ± 49 s, with most residuals very close to zero. This allows us to place an upper limit of 5-10 M [subscript ⊕] for a coplanar, low-eccentricity perturber in either the 2:1 or 3:2 mean-motion resonance with OGLE-TR-132b. We similarly find that the data are entirely consistent with a constant orbital period and there is no evidence for orbital decay within the limits of precision of our data.United States. National Aeronautics and Space Administration (Origins Grant NNX07AN63G
Six High-Precision Transits of Ogle-Tr-113b
We present six new transits of the hot Jupiter OGLE-TR-113b observed with MagIC on the Magellan
Telescopes between 2007 January and 2009 May. We update the system parameters and revise the planetary radius to R[subscript p] = 1.084 ± 0.029R[subscript J] , where the error is dominated by stellar radius uncertainties. The new transit midtimes reveal no transit timing variations from a constant ephemeris of greater than 13 ± 28 s over two years, placing an upper limit of 1–2M[subscript ⊕] on the mass of any perturber in a 1:2 or 2:1 mean-motion resonance with OGLETR-
113b. Combining the new transit epochs with five epochs published between 2002 and 2006, we find hints that the orbital period of the planet may not be constant, with the best fit indicating a decrease of [dot over P] = −60±15 ms yr−1. If real, this change in period could result from either a long-period (more than eight years) timing variation due to a massive external perturber or more intriguingly from the orbital decay of the planet. The detection of a changing period is still tentative and requires additional observations, but if confirmed it would enable direct tests of tidal stability and dynamical models of close-in planets.United States. National Aeronautics and Space Administration (Origins Grant NNX07AN63G
Determining the Relationship Between Seizure-Free Days and Other Predictors of Quality of Life in Patients with Dravet Syndrome and Their Carers from FFA Registration Studies
INTRODUCTION
Dravet syndrome (DS) is a rare, lifelong epileptic encephalopathy characterised by frequent and severe seizures associated with premature mortality. Typically diagnosed in infancy, patients also experience progressive behavioural, motor-function and cognitive decline. Twenty percent of patients do not reach adulthood. Quality of life (QoL) is impaired for both patients and their carers. Reducing convulsive seizure frequency, increasing convulsive seizure-free days (SFDs) and improving patient/carer QoL are primary treatment goals in DS. This study explored the relationship between SFDs and patients' and carers' QoL to inform a cost-utility analysis of fenfluramine (FFA).
METHODS
In FFA registration studies, patients (or their carer proxies) completed the Paediatric QoL inventory (PedsQL). These data were mapped to EuroQol-5 Dimensions Youth version (EQ-5D-Y) to provide patient utilities. Carer utilities were collected using EQ-5D-5L and mapped to EQ-5D-3L to align patient and carer QoL on the same scale. Linear mixed-effects and panel regression models were tested and Hausman tests identified the most appropriate approach for each group. On this basis, a linear mixed-effects regression model was used to examine the relationships between patient EQ-5D-Y and clinically relevant variables (age, frequency of SFDs per 28 days, motor impairments and treatment dose). A linear panel regression model examined the relationship between SFDs and carer QoL.
RESULTS
After adjustment for age and underlying comorbidities, the patient regression model showed that SFDs per 28 days was a significant predictor of QoL. Each additional patient-SFD increased utility by 0.005 (p < 0.001). The carer linear panel model also showed that increasing SFDs per 28 days was a significant predictor of improved QoL. Each additional SFD increased carer utility by 0.014 (p < 0.001).
CONCLUSION
This regression framework highlights that SFDs are significantly correlated with both patients' and carers' QoL. Treatment with effective antiseizure medications that increase SFDs directly improves QoL for patients and their carers
Antimicrobial resistance point-of-care testing for gonorrhoea treatment regimens: cost-effectiveness and impact on ceftriaxone use of five hypothetical strategies compared with standard care in England sexual health clinics.
BackgroundWidespread ceftriaxone antimicrobial resistance (AMR) threatens Neisseria gonorrhoeae (NG) treatment, with few alternatives available. AMR point-of-care tests (AMR POCT) may enable alternative treatments, including abandoned regimens, sparing ceftriaxone use. We assessed cost-effectiveness of five hypothetical AMR POCT strategies: A-C included a second antibiotic alongside ceftriaxone; and D and E consisted of a single antibiotic alternative, compared with standard care (SC: ceftriaxone and azithromycin).AimAssess costs and effectiveness of AMR POCT strategies that optimise NG treatment and reduce ceftriaxone use.MethodsThe five AMR POCT treatment strategies were compared using a decision tree model simulating 38,870 NG-diagnosed England sexual health clinic (SHC) attendees; A micro-costing approach, representing cost to the SHC (for 2015/16), was employed. Primary outcomes were: total costs; percentage of patients given optimal treatment (regimens curing NG, without AMR); percentage of patients given non-ceftriaxone optimal treatment; cost-effectiveness (cost per optimal treatment gained).ResultsAll strategies cost more than SC. Strategy B (azithromycin and ciprofloxacin (azithromycin preferred); dual therapy) avoided most suboptimal treatments (n = 48) but cost most to implement (GBP 4,093,844 (EUR 5,474,656)). Strategy D (azithromycin AMR POCT; monotherapy) was most cost-effective for both cost per optimal treatments gained (GBP 414.67 (EUR 554.53)) and per ceftriaxone-sparing treatment (GBP 11.29 (EUR 15.09)) but with treatment failures (n = 34) and suboptimal treatments (n = 706).ConclusionsAMR POCT may enable improved antibiotic stewardship, but require net health system investment. A small reduction in test cost would enable monotherapy AMR POCT strategies to be cost-saving
Quality management in heavy duty manufacturing industry: TQM vs. Six Sigma
‘Is TQM a management fad?’ This question has been extensively documented in the quality management literature; and will be tackled in this research though a critical literature review on the area. ‘TQM versus Six-Sigma’ debate, which has also been a fundamental challenge in this research filed, is addressed by a thematic and chronological review on the peer papers. To evaluate this challenge in practice, a primary research in heavy duty machinery production industry have been conducted using a case-study on, J C Bamford Excavators Ltd (JCB), the largest European construction machinery producer. The result highlights that TQM is a natural foundation to build up Six-Sigma upon; and not surprisingly the quality yield in a TQM approach complemented by Six-sigma is far higher and more stable than when TQM with no Six-Sigma focus is being put in place; thus presenting the overall finding that TQM and Six Sigma are compliments, not substitutes. The study will be concluded with an overview on quality management approaches in the heavy duty manufacturing industry to highlight the way forward for the industry
Quantitative Chemically-Specific Coherent Diffractive Imaging of Buried Interfaces using a Tabletop EUV Nanoscope
Characterizing buried layers and interfaces is critical for a host of
applications in nanoscience and nano-manufacturing. Here we demonstrate
non-invasive, non-destructive imaging of buried interfaces using a tabletop,
extreme ultraviolet (EUV), coherent diffractive imaging (CDI) nanoscope. Copper
nanostructures inlaid in SiO2 are coated with 100 nm of aluminum, which is
opaque to visible light and thick enough that neither optical microscopy nor
atomic force microscopy can image the buried interfaces. Short wavelength (29
nm) high harmonic light can penetrate the aluminum layer, yielding
high-contrast images of the buried structures. Moreover, differences in the
absolute reflectivity of the interfaces before and after coating reveal the
formation of interstitial diffusion and oxidation layers at the Al-Cu and
Al-SiO2 boundaries. Finally, we show that EUV CDI provides a unique capability
for quantitative, chemically-specific imaging of buried structures, and the
material evolution that occurs at these buried interfaces, compared with all
other approaches.Comment: 12 pages, 8 figure
Using Seroprevalence and Immunisation Coverage Data to Estimate the Global Burden of Congenital Rubella Syndrome, 1996-2010: A Systematic Review.
BACKGROUND: The burden of Congenital Rubella Syndrome (CRS) is typically underestimated in routine surveillance. Updated estimates are needed following the recent WHO position paper on rubella and recent GAVI initiatives, funding rubella vaccination in eligible countries. Previous estimates considered the year 1996 and only 78 (developing) countries. METHODS: We reviewed the literature to identify rubella seroprevalence studies conducted before countries introduced rubella-containing vaccination (RCV). These data and the estimated vaccination coverage in the routine schedule and mass campaigns were incorporated in mathematical models to estimate the CRS incidence in 1996 and 2000-2010 for each country, region and globally. RESULTS: The estimated CRS decreased in the three regions (Americas, Europe and Eastern Mediterranean) which had introduced widespread RCV by 2010, reaching <2 per 100,000 live births (the Americas and Europe) and 25 (95% CI 4-61) per 100,000 live births (the Eastern Mediterranean). The estimated incidence in 2010 ranged from 90 (95% CI: 46-195) in the Western Pacific, excluding China, to 116 (95% CI: 56-235) and 121 (95% CI: 31-238) per 100,000 live births in Africa and SE Asia respectively. Highest numbers of cases were predicted in Africa (39,000, 95% CI: 18,000-80,000) and SE Asia (49,000, 95% CI: 11,000-97,000). In 2010, 105,000 (95% CI: 54,000-158,000) CRS cases were estimated globally, compared to 119,000 (95% CI: 72,000-169,000) in 1996. CONCLUSIONS: Whilst falling dramatically in the Americas, Europe and the Eastern Mediterranean after vaccination, the estimated CRS incidence remains high elsewhere. Well-conducted seroprevalence studies can help to improve the reliability of these estimates and monitor the impact of rubella vaccination
Rapid testing and treatment for sexually transmitted infections improve patient care and yield public health benefits
A service evaluation of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) testing and result notification in patients attending a rapid testing service (Dean Street Express [DSE]) compared with those attending an existing ‘standard’ sexual health clinic (56 Dean Street [56DS]), and modelling the impact of the new service from 1 June 2014 to 31 May 2015. Primary outcome: time from patients’ sample collection to notification of test results at DSE compared with 56DS. Secondary outcomes estimated using a model: number of transmissions prevented and the number of new partner visits avoided and associated cost savings achieved due to rapid testing at DSE. In 2014/15, there were a total of 81,352 visits for CT/NG testing across 56DS (21,086) and DSE (60,266). Rapid testing resulted in a reduced mean time to notification of 8.68 days: 8.95 days for 56DS (95% CI 8.91–8.99) compared to 0.27 days for DSE (95% CI 0.26–0.28). Our model estimates that rapid testing at DSE would lead to 196 CT and/or NG transmissions prevented (2.5–97.5% centile range = 6–956) and lead to annual savings attributable to reduced numbers of partner attendances of £124,283 (2.5–97.5% centile range = £4260–590,331). DSE, a rapid testing service for asymptomatic infections, delivers faster time to result notification for CT and/or NG which enables faster treatment, reduces infectious periods and leads to fewer transmissions, partner attendances and clinic costs. </jats:p
Pessaries (mechanical devices) for managing pelvic organ prolapse in women
Background Pelvic organ prolapse is a common problem in women. About 40% of women will experience prolapse in their lifetime, with the proportion expected to rise in line with an ageing population. Women experience a variety of troublesome symptoms as a consequence of prolapse, including a feeling of 'something coming down' into the vagina, pain, urinary symptoms, bowel symptoms and sexual difficulties. Treatment for prolapse includes surgery, pelvic floor muscle training (PFMT) and vaginal pessaries. Vaginal pessaries are passive mechanical devices designed to support the vagina and hold the prolapsed organs back in the anatomically correct position. The most commonly used pessaries are made from polyvinyl‐chloride, polythene, silicone or latex. Pessaries are frequently used by clinicians with high numbers of clinicians offering a pessary as first‐line treatment for prolapse. This is an update of a Cochrane Review first published in 2003 and last published in 2013. Objectives To assess the effects of pessaries (mechanical devices) for managing pelvic organ prolapse in women; and summarise the principal findings of relevant economic evaluations of this intervention. Search methods We searched the Cochrane Incontinence Specialised Register which contains trials identified from the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, MEDLINE In‐Process, MEDLINE Epub Ahead of Print, ClinicalTrials.gov, WHO ICTRP and handsearching of journals and conference proceedings (searched 28 January 2020). We searched the reference lists of relevant articles and contacted the authors of included studies. Selection criteria We included randomised and quasi‐randomised controlled trials which included a pessary for pelvic organ prolapse in at least one arm of the study. Data collection and analysis Two review authors independently assessed abstracts, extracted data, assessed risk of bias and carried out GRADE assessments with arbitration from a third review author if necessary. Main results We included four studies involving a total of 478 women with various stages of prolapse, all of which took place in high‐income countries. In one trial, only six of the 113 recruited women consented to random assignment to an intervention and no data are available for those six women. We could not perform any meta‐analysis because each of the trials addressed a different comparison. None of the trials reported data about perceived resolution of prolapse symptoms or about psychological outcome measures. All studies reported data about perceived improvement of prolapse symptoms. Generally, the trials were at high risk of performance bias, due to lack of blinding, and low risk of selection bias. We downgraded the certainty of evidence for imprecision resulting from the low numbers of women participating in the trials. Pessary versus no treatment: at 12 months' follow‐up, we are uncertain about the effect of pessaries compared with no treatment on perceived improvement of prolapse symptoms (mean difference (MD) in questionnaire scores ‐0.03, 95% confidence interval (CI) ‐0.61 to 0.55; 27 women; 1 study; very low‐certainty evidence), and cure or improvement of sexual problems (MD ‐0.29, 95% CI ‐1.67 to 1.09; 27 women; 1 study; very low‐certainty evidence). In this comparison we did not find any evidence relating to prolapse‐specific quality of life or to the number of women experiencing adverse events (abnormal vaginal bleeding or de novo voiding difficulty). Pessary versus pelvic floor muscle training (PFMT): at 12 months' follow‐up, we are uncertain if there is a difference between pessaries and PFMT in terms of women's perceived improvement in prolapse symptoms (MD ‐9.60, 95% CI ‐22.53 to 3.33; 137 women; low‐certainty evidence), prolapse‐specific quality of life (MD ‐3.30, 95% CI ‐8.70 to 15.30; 1 study; 116 women; low‐certainty evidence), or cure or improvement of sexual problems (MD ‐2.30, 95% ‐5.20 to 0.60; 1 study; 48 women; low‐certainty evidence). Pessaries may result in a large increase in risk of adverse events compared with PFMT (RR 75.25, 95% CI 4.70 to 1205.45; 1 study; 97 women; low‐certainty evidence). Adverse events included increased vaginal discharge, and/or increased urinary incontinence and/or erosion or irritation of the vaginal walls. Pessary plus PFMT versus PFMT alone: at 12 months' follow‐up, pessary plus PFMT probably leads to more women perceiving improvement in their prolapse symptoms compared with PFMT alone (RR 2.15, 95% CI 1.58 to 2.94; 1 study; 260 women; moderate‐certainty evidence). At 12 months' follow‐up, pessary plus PFMT probably improves women's prolapse‐specific quality of life compared with PFMT alone (median (interquartile range (IQR)) POPIQ score: pessary plus PFMT 0.3 (0 to 22.2); 132 women; PFMT only 8.9 (0 to 64.9); 128 women; P = 0.02; moderate‐certainty evidence). Pessary plus PFMT may slightly increase the risk of abnormal vaginal bleeding compared with PFMT alone (RR 2.18, 95% CI 0.69 to 6.91; 1 study; 260 women; low‐certainty evidence). The evidence is uncertain if pessary plus PFMT has any effect on the risk of de novo voiding difficulty compared with PFMT alone (RR 1.32, 95% CI 0.54 to 3.19; 1 study; 189 women; low‐certainty evidence). Authors' conclusions We are uncertain if pessaries improve pelvic organ prolapse symptoms for women compared with no treatment or PFMT but pessaries in addition to PFMT probably improve women's pelvic organ prolapse symptoms and prolapse‐specific quality of life. However, there may be an increased risk of adverse events with pessaries compared to PFMT. Future trials should recruit adequate numbers of women and measure clinically important outcomes such as prolapse specific quality of life and resolution of prolapse symptoms. The review found two relevant economic evaluations. Of these, one assessed the cost‐effectiveness of pessary treatment, expectant management and surgical procedures, and the other compared pessary treatment to PFMT
Transit Timing Observations from Kepler: VII. Confirmation of 27 planets in 13 multiplanet systems via Transit Timing Variations and orbital stability
We confirm 27 planets in 13 planetary systems by showing the existence of
statistically significant anti-correlated transit timing variations (TTVs),
which demonstrates that the planet candidates are in the same system, and
long-term dynamical stability, which places limits on the masses of the
candidates---showing that they are planetary. %This overall method of planet
confirmation was first applied to \kepler systems 23 through 32. All of these
newly confirmed planetary systems have orbital periods that place them near
first-order mean motion resonances (MMRs), including 6 systems near the 2:1
MMR, 5 near 3:2, and one each near 4:3, 5:4, and 6:5. In addition, several
unconfirmed planet candidates exist in some systems (that cannot be confirmed
with this method at this time). A few of these candidates would also be near
first order MMRs with either the confirmed planets or with other candidates.
One system of particular interest, Kepler-56 (KOI-1241), is a pair of planets
orbiting a 12th magnitude, giant star with radius over three times that of the
Sun and effective temperature of 4900 K---among the largest stars known to host
a transiting exoplanetary system.Comment: 12 pages, 13 figures, 5 tables. Submitted to MNRA
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