Spitzer and z' Secondary Eclipse Observations of the Highly Irradiated Transiting Brown Dwarf KELT-1b

We present secondary eclipse observations of the highly irradiated transiting brown dwarf KELT-1b. These observations represent the first constraints on the atmospheric dynamics of a highly irradiated brown dwarf, and the atmospheres of irradiated giant planets at high surface gravity. Using the Spitzer Space Telescope, we measure secondary eclipse depths of 0.195+/-0.010% at 3.6um and 0.200+/-0.012% at 4.5um. We also find tentative evidence for the secondary eclipse in the z' band with a depth of 0.049+/-0.023%. These measured eclipse depths are most consistent with an atmosphere model in which there is a strong substellar hotspot, implying that heat redistribution in the atmosphere of KELT-1b is low. While models with a more mild hotspot or even with dayside heat redistribution are only marginally disfavored, models with complete heat redistribution are strongly ruled out. The eclipse depths also prefer an atmosphere with no TiO inversion layer, although a model with TiO inversion is permitted in the dayside heat redistribution case, and we consider the possibility of a day-night TiO cold trap in this object. For the first time, we compare the IRAC colors of brown dwarfs and hot Jupiters as a function of effective temperature. Importantly, our measurements reveal that KELT-1b has a [3.6]-[4.5] color of 0.07+/-0.11, identical to that of isolated brown dwarfs of similarly high temperature. In contrast, hot Jupiters generally show redder [3.6]-[4.5] colors of ~0.4, with a very large range from ~0 to ~1. Evidently, despite being more similar to hot Jupiters than to isolated brown dwarfs in terms of external forcing of the atmosphere by stellar insolation, KELT-1b has an atmosphere most like that of other brown dwarfs. This suggests that surface gravity is very important in controlling the atmospheric systems of substellar mass bodies.Comment: 14 pages, 3 tables, 11 figures. Accepted by ApJ. Updated to reflect the accepted versio

A randomised controlled trial and cost-effectiveness evaluation of 'booster' interventions to sustain increases in physical activity in middle-aged adults in deprived urban neighbourhoods

Background: More evidence is needed on the potential role of 'booster' interventions in the maintenance of increases in physical activity levels after a brief intervention in relatively sedentary populations. Objectives: To determine whether objectively measured physical activity, 6 months after a brief intervention, is increased in those receiving physical activity 'booster' consultations delivered in a motivational interviewing (MI) style, either face to face or by telephone. Design: Three-arm, parallel-group, pragmatic, superiority randomised controlled trial with nested qualitative research fidelity and geographical information systems and health economic substudies. Treatment allocation was carried out using a web-based simple randomisation procedure with equal allocation probabilities. Principal investigators and study statisticians were blinded to treatment allocation until after the final analysis only. Setting: Deprived areas of Sheffield, UK. Participants: Previously sedentary people, aged 40-64 years, living in deprived areas of Sheffield, UK, who had increased their physical activity levels after receiving a brief intervention. Interventions: Participants were randomised to the control group (no further intervention) or to two sessions of MI, either face to face ('full booster') or by telephone ('mini booster'). Sessions were delivered 1 and 2 months post-randomisation. Main outcome measures: The primary outcome was total energy expenditure (TEE) per day in kcal from 7-day accelerometry, measured using an Actiheart device (CamNtech Ltd, Cambridge, UK). Independent evaluation of practitioner competence was carried out using the Motivational Interviewing Treatment Integrity assessment. An estimate of the per-participant intervention costs, resource use data collected by questionnaire and health-related quality of life data were analysed to produce a range of economic models from a short-term NHS perspective. An additional series of models were developed that used TEE values to estimate the long-term cost-effectiveness. Results: In total, 282 people were randomised (control = 96; mini booster = 92, full booster = 94) of whom 160 had a minimum of 4 out of 7 days' accelerometry data at 3 months (control = 61, mini booster = 47, full booster = 52). The mean difference in TEE per day between baseline and 3 months favoured the control arm over the combined booster arm but this was not statistically significant (-39 kcal, 95% confidence interval -173 to 95, p = 0.57). The autonomy-enabled MI communication style was generally acceptable, although some participants wanted a more paternalistic approach and most expressed enthusiasm for monitoring and feedback components of the intervention and research. Full boosters were more popular than mini boosters. Practitioners achieved and maintained a consistent level of MI competence. Walking distance to the nearest municipal green space or leisure facilities was not associated with physical activity levels. Two alternative modelling approaches both suggested that neither intervention was likely to be cost-effective. Conclusions: Although some individuals do find a community-based, brief MI 'booster' intervention supportive, the low levels of recruitment and retention and the lack of impact on objectively measured physical activity levels in those with adequate outcome data suggest that it is unlikely to represent a clinically effective or cost-effective intervention for the maintenance of recently acquired physical activity increases in deprived middle-aged urban populations. Future research with middle-aged and relatively deprived populations should explore interventions to promote physical activity that require less proactive engagement from individuals, including environmental interventions

Spontaneous Clearance Of Vertically Acquired Hepatitis C Infection: Implications For Testing And Treatment

BACKGROUND: Current guidelines recommend that infants born to women with hepatitis C (HCV) viremia are screened for HCV antibody at age 18 months, and if positive, referred for RNA testing at 3 years to confirm chronic infection. This policy is based in part on analyses suggesting 25%-40% of vertically acquired HCV infections clear spontaneously within 4-5 years. METHODS: Data on 179 infants with HCV RNA and/or anti-HCV evidence of vertically acquired infection in three prospective European cohorts were investigated. Ages at clearance of infection were estimated taking account of interval censoring and delayed entry. We also investigated clearance in initially HCV RNA negative infants in whom RNA was not detectable until after 6 weeks. RESULTS: Clearance rates are initially high then decline slowly. Apparently, many infections clear before they can be confirmed. An estimated 65.9% (50.1-81.6) of confirmed infections cleared by 5 years, at a median 12.4 (7.1-18.9) months. If treatment began at age 6 months, 18 months or 3 years, at least 59.0% (42.0-76.9), 39.7% (17.9-65.9), and 20.9% (4.6-44.8) of those treated would clear without treatment. In seven (6.6%) confirmed infections, RNA was not detectable until after 6 weeks, and in 2 (1.9%) not until after 6 months. However, all such cases subsequently cleared. CONCLUSIONS: Most confirmed infection clears by age 3 years. Treatment before age 3, if it was available, would avoid loss to follow-up, but would result in substantial over-treatment

Overall vertical transmission of HCV, transmission net of clearance, and timing of transmission

Background: It is widely accepted that the risk of HCV vertical transmission (VT) is 5-6% in mono-infected women, and that 25-40% of HCV infection clears spontaneously within 5 years. However, there is no consensus on how VT rates should be estimated, and there is a lack of information on VT rates “net” of clearance. // Methods: We re-analysed data on 1749 children in 3 prospective cohorts to obtain coherent estimates of overall VT rate and VT rates “net” of clearance at different ages. Clearance rates were used to impute the proportion of uninfected children who had been infected and then cleared before testing negative. The proportion of transmission early in utero, late in utero and at delivery was estimated from data on the proportion of HCV RNA positive within three days of birth, and differences between elective caesarean and non-elective caesarean deliveries. // Findings: Overall VT rates were 7.2% (95% credible interval 5.6-8.9) in mothers who were HIV negative and 12.1% (8.6-16.8) in HIV-co-infected women. The corresponding rates net of clearance at 5 years were 2.4% (1.1-4.1) and 4.1% (1.7-7.3). We estimated that 24.8% (12.1-40.8) of infections occur early in utero, 66.0% (42.5-83.3) later in utero, and 9.3% (0.5-30.6) during delivery. // Conclusion: Overall VT rates are about 24% higher than previously assumed, but the risk of infection persisting beyond age 5 years is about 38% lower. The results can inform design of trials of to prevent or treat pediatric HCV infection, and strategies to manage children exposed in utero

Modelling the potential effectiveness of hepatitis C screening and treatment strategies during pregnancy in Egypt and Ukraine

BACKGROUND & AIMS: Hepatitis C (HCV) test and treat campaigns currently excludes pregnant women. Pregnancy offers a unique opportunity for HCV screening and to potentially initiate direct-acting-antiviral treatment. We explored HCV screening and treatment strategies in two lower middle-income countries with high HCV prevalence, Egypt and Ukraine. METHODS: Country-specific probabilistic decision models were developed to simulate a cohort of pregnant women. We compared five strategies: S0, targeted risk-based screening and deferred treatment (DT) to after pregnancy/breastfeeding; S1, WHO risk-based screening and DT; S2, WHO risk-based screening and targeted treatment (treat women with risk factors for HCV vertical transmission (VT)); S3, universal screening and targeted treatment during pregnancy; S4, universal screening and treatment. Maternal and infant HCV outcomes were projected. RESULTS: S0 resulted in the highest proportion of women undiagnosed:59% and 20% in Egypt and Ukraine, respectively, with 0% maternal cure by delivery and VT estimated at 6.5% and 7.9%, respectively. WHO risk-based screening and DT (S1) increased the proportion of women diagnosed with no change in maternal cure or VT. Universal screening and treatment during pregnancy (S4) resulted in the highest proportion of women diagnosed and cured by delivery (65% and 70% respectively), and lower levels of VT (3.4% and 3.6% respectively). CONCLUSIONS: This is one of the first models to explore HCV screening and treatment strategies in pregnancy, which will be critical in informing future care and policy as more safety/efficacy data emerge. Universal screening and treatment in pregnancy could potentially improve both maternal and infant outcomes. IMPACT AND IMPLICATIONS: In the context of two lower middle-income countries with high HCV burden (Egypt and Ukraine), we designed a decision analytic model to explore five different HCV testing and treatment strategies for pregnant women, with the assumption that treatment was safe and efficacious for use in pregnancy. Assuming DAAs in pregnancy reduced vertical transmission, model findings indicate optimal maternal and infant benefits with provision of universal (rather than risk-based targeted) screening and treatment during pregnancy: the proportion of women diagnosed and cured by delivery would be 65% in Egypt and 70% in Ukraine (versus 0% with standard of care), and the proportion of infants that would be infected at the age of 6 months would decrease from 6.5% to 3.4% in Egypt, and from 7.9% to 3.6% in Ukraine, compared to standard of care. While future trials are needed to assess safety and efficacy of DAA treatment in pregnancy and impact on VT, there is increasing recognition that the elimination of HCV cannot leave entire subpopulations of pregnant women and young children behind. Our findings will be critical in informing policymakers in improving screening and treatment recommendations for pregnant women

KELT-1b: A Strongly Irradiated, Highly Inflated, Short Period, 27 Jupiter-mass Companion Transiting a mid-F Star

We present the discovery of KELT-1b, the first transiting low-mass companion from the wide-field Kilodegree Extremely Little Telescope-North (KELT-North) survey. The V=10.7 primary is a mildly evolved, solar-metallicity, mid-F star. The companion is a low-mass brown dwarf or super-massive planet with mass of 27.23+/-0.50 MJ and radius of 1.110+0.037-0.024 RJ, on a very short period (P=1.21750007) circular orbit. KELT-1b receives a large amount of stellar insolation, with an equilibrium temperature assuming zero albedo and perfect redistribution of 2422 K. Upper limits on the secondary eclipse depth indicate that either the companion must have a non-zero albedo, or it must experience some energy redistribution. Comparison with standard evolutionary models for brown dwarfs suggests that the radius of KELT-1b is significantly inflated. Adaptive optics imaging reveals a candidate stellar companion to KELT-1, which is consistent with an M dwarf if bound. The projected spin-orbit alignment angle is consistent with zero stellar obliquity, and the vsini of the primary is consistent with tidal synchronization. Given the extreme parameters of the KELT-1 system, we expect it to provide an important testbed for theories of the emplacement and evolution of short-period companions, and theories of tidal dissipation and irradiated brown dwarf atmospheres.Comment: 30 pages, 19 figures. Submitted to Ap