Wind tunnel performance results of an aeroelastically scaled 2/9 model of the PTA flight test prop-fan

High speed wind tunnel aerodynamic performance tests of the SR-7A advanced prop-fan have been completed in support of the Prop-Fan Test Assessment (PTA) flight test program. The test showed that the SR-7A model performed aerodynamically very well. At the cruise design condition, the SR-7A prop fan had a high measured net efficiency of 79.3 percent

Intergenerational mobility and the effects of parental education, time investment, and income on children’s educational attainment

This article analyzes the mechanisms through which parents’ and children’s education are linked. It estimates the causal effect of parental education, parental time with children, and parental income during early childhood on the educational outcomes of children. Estimating the causal effects of time with children, income, and parental education is challenging because parental time with children is usually unavailable in many datasets and because of the problem of endogeneity of parental income, time with children, and education. The authors, therefore, use an instrumental variables approach to estimate the causal effects. They find that once they account for the parental time input with children, parental income during the first five years is no longer statistically significant. The parental time investments of both parents in early childhood are each statistically and quantitatively significant determinants of the educational outcomes of children.Publisher versio

Estimation of dynastic lifecycle discrete choice models

This paper explores the estimation of a class of life‐cycle discrete choice dynastic models. It provides a new representation of the value function for these class of models. It compare a multistage conditional choice probability (CCP) estimator based on the new value function representation with a modified version of the full solution maximum likelihood estimator (MLE) in a Monte Carlo study. The modified CCP estimator performs comparably to the MLE in a finite sample but greatly reduces the computational cost. Using the proposed estimator, we estimate a dynastic model and use the estimated model to conduct counterfactual simulations to investigate the role Nature versus Nurture in intergenerational mobility. We find that Nature accounts for 20 percent of the observed intergenerational immobility at the bottom of income distribution. That means that 80 percent of mobility at the bottom of the income distribution is explained by economic decision and economic/institutional constraints.Publisher versio

Estimation of dynastic lifecycle discrete choice models

This paper explores the estimation of a class of life‐cycle discrete choice dynastic models. It provides a new representation of the value function for these class of models. It compare a multistage conditional choice probability (CCP) estimator based on the new value function representation with a modified version of the full solution maximum likelihood estimator (MLE) in a Monte Carlo study. The modified CCP estimator performs comparably to the MLE in a finite sample but greatly reduces the computational cost. Using the proposed estimator, we estimate a dynastic model and use the estimated model to conduct counterfactual simulations to investigate the role Nature versus Nurture in intergenerational mobility. We find that Nature accounts for 20 percent of the observed intergenerational immobility at the bottom of income distribution. That means that 80 percent of mobility at the bottom of the income distribution is explained by economic decision and economic/institutional constraints.Publisher versio

Autism and the U.K. secondary school experience

This research investigated the self-reported mainstream school experiences of those diagnosed on the autistic spectrum compared with the typically developing school population. Existing literature identifies four key areas that affect the quality of the school experience for students with autism: social skills, perceived relationships with teaching staff, general school functioning, and interpersonal strengths of the young person. These areas were explored in a mainstream U.K. secondary school with 14 students with autism and 14 age and gender matched students without autism, using self-report questionnaires and semi-structured interviews. Quantitative analyses showed consistent school experiences for both groups, although content analysis of interview data highlighted some differences in the ways in which the groups perceive group work, peers, and teaching staff within school. Implications for school inclusion are discussed, drawing attention to how staff awareness of autism could improve school experience and success for students with autism attending mainstream schools

Rationale and design of the GUIDE-IT study: Guiding Evidence Based Therapy Using Biomarker Intensified Treatment in Heart Failure.

OBJECTIVES: The GUIDE-IT (Guiding Evidence Based Therapy Using Biomarker Intensified Treatment in Heart Failure) study is designed to determine the safety, efficacy, and cost-effectiveness of a strategy of adjusting therapy with the goal of achieving and maintaining a target N-terminal pro-B-type natriuretic peptide (NT-proBNP) level of BACKGROUND: Elevations in natriuretic peptide (NP) levels provide key prognostic information in patients with HF. Therapies proven to improve outcomes in patients with HF are generally associated with decreasing levels of NPs, and observational data show that decreases in NP levels over time are associated with favorable outcomes. Results from smaller prospective, randomized studies of this strategy thus far have been mixed, and current guidelines do not recommend serial measurement of NP levels to guide therapy in patients with HF. METHODS: GUIDE-IT is a prospective, randomized, controlled, unblinded, multicenter clinical trial designed to randomize approximately 1,100 high-risk subjects with systolic HF (left ventricular ejection fraction ≤40%) to either usual care (optimized guideline-recommended therapy) or a strategy of adjusting therapy with the goal of achieving and maintaining a target NT-proBNP level of CONCLUSIONS: The GUIDE-IT study is designed to definitively assess the effects of an NP-guided strategy in high-risk patients with systolic HF on clinically relevant endpoints of mortality, hospitalization, quality of life, and medical resource use. (Guiding Evidence Based Therapy Using Biomarker Intensified Treatment in Heart Failure [GUIDE-IT]; NCT01685840)

Effect of Natriuretic Peptide-Guided Therapy on Hospitalization or Cardiovascular Mortality in High-Risk Patients With Heart Failure and Reduced Ejection Fraction: A Randomized Clinical Trial.

Importance: The natriuretic peptides are biochemical markers of heart failure (HF) severity and predictors of adverse outcomes. Smaller studies have evaluated adjusting HF therapy based on natriuretic peptide levels ( guided therapy ) with inconsistent results. Objective: To determine whether an amino-terminal pro-B-type natriuretic peptide (NT-proBNP)-guided treatment strategy improves clinical outcomes vs usual care in high-risk patients with HF and reduced ejection fraction (HFrEF). Design, Settings, and Participants: The Guiding Evidence Based Therapy Using Biomarker Intensified Treatment in Heart Failure (GUIDE-IT) study was a randomized multicenter clinical trial conducted between January 16, 2013, and September 20, 2016, at 45 clinical sites in the United States and Canada. This study planned to randomize 1100 patients with HFrEF (ejection fraction ≤40%), elevated natriuretic peptide levels within the prior 30 days, and a history of a prior HF event (HF hospitalization or equivalent) to either an NT-proBNP-guided strategy or usual care. Interventions: Patients were randomized to either an NT-proBNP-guided strategy or usual care. Patients randomized to the guided strategy (n = 446) had HF therapy titrated with the goal of achieving a target NT-proBNP of less than 1000 pg/mL. Patients randomized to usual care (n = 448) had HF care in accordance with published guidelines, with emphasis on titration of proven neurohormonal therapies for HF. Serial measurement of NT-proBNP testing was discouraged in the usual care group. Main Outcomes and Measures: The primary end point was the composite of time-to-first HF hospitalization or cardiovascular mortality. Prespecified secondary end points included all-cause mortality, total hospitalizations for HF, days alive and not hospitalized for cardiovascular reasons, the individual components on the primary end point, and adverse events. Results: The data and safety monitoring board recommended stopping the study for futility when 894 (median age, 63 years; 286 [32%] women) of the planned 1100 patients had been enrolled with follow-up for a median of 15 months. The primary end point occurred in 164 patients (37%) in the biomarker-guided group and 164 patients (37%) in the usual care group (adjusted hazard ratio [HR], 0.98; 95% CI, 0.79-1.22; P = .88). Cardiovascular mortality was 12% (n = 53) in the biomarker-guided group and 13% (n = 57) in the usual care group (HR, 0.94; 95% CI; 0.65-1.37; P = .75). None of the secondary end points nor the decreases in the NT-proBNP levels achieved differed significantly between groups. Conclusions and Relevance: In high-risk patients with HFrEF, a strategy of NT-proBNP-guided therapy was not more effective than a usual care strategy in improving outcomes. Trial Registration: clinicaltrials.gov Identifier: NCT01685840

Perioperative donor bone marrow infusion augments chimerism in heart and lung transplant recipients

Background.: We and others have demonstrated that a low level of donor cell chimerism was present for years after transplantation in tissues and peripheral blood of heart and lung recipients; it was associated, in the latter, with a lower incidence of chronic rejection. To augment this phenomenon, we initiated a trial combining simultaneous infusion of donor bone marrow with heart or lung allotransplantation. Methods.: Between September 1993 and January 1995, 15 nonconditioned patients received either heart (n = 10) or lung (n = 5) allografts concurrently with an infusion of unmodified donor bone marrow (3.0 × 108 cells/kg), and were maintained on an immunosuppressive regimen consisting of tacrolimus and steroids. Results.: There was no complication associated with the infusion of donor bone marrow. Chimerism was detectable in 73% of bone marrow-augmented patients up to the last sample tested. Of the 5 control recipients who did not receive bone marrow infusion, only 1 had detectable chimerism by flow on postoperative day 15, which dwindled to an undetectable level by postoperative day 36. None of the patients had evidence of donor-specific immune modulation by mixed lymphocyte reaction. Conclusions.: The combined infusion of donor bone marrow and heart or lung transplantation, without preconditioning of the recipient, is safe and is associated with an augmentation of donor cell chimerism. © 1995 The Society of Thoracic Surgeons

Elimination of mother-to-child transmission of HIV in South Africa : rapid scale-up using quality improvement

BACKGROUND. South Africa (SA) is committed to achieving the goal of eliminating mother-to-child transmission (MTCT) of HIV by 2015. To achieve this, universal coverage of quality antenatal, labour, delivery and postnatal services for all women has to be attained. Over the past decade, the prevention of mother-to-child transmission (PMTCT) programme has been scaled up to reach all healthcare facilities in the country. However, challenges persist in achieving 100% coverage and access to the programme. OBJECTIVES. We describe the process undertaken by the National Department of Health (NDoH), in collaboration with partners, to develop, implement and monitor a data-driven intervention to improve facility, district, provincial and national PMTCT-related performance. METHODS. Between 2011 and 2013, the NDoH developed and implemented an intervention using data-driven participatory processes to understand facility-level bottlenecks to optimise PMTCT implementation and to scale up priority PMTCT actions nationally. RESULTS. There was remarkable improvement across all key indicators in the PMTCT cascade over the 3 years 2011 - 2013. Simple monitoring tools such as a visual dashboard and data for action reports were successfully used to improve the performance of the PMTCT programme across SA. MTCT has shown a significant downward trend. CONCLUSIONS. It is feasible to implement district-level, data-driven quality improvement processes at a national scale to improve the performance of the PMTCT programme at the local level.http://www.samj.org.zaam201

Efimov three-body states on top of a Fermi sea

The stabilization of Cooper pairs of bound electrons in the background of a Fermi sea is the origin of superconductivity and the paradigmatic example of the striking influence of many-body physics on few-body properties. In the quantum-mechanical three-body problem the famous Efimov effect yields unexpected scaling relations among a tower of universal states. These seemingly unrelated problems can now be studied in the same setup thanks to the success of ultracold atomic gas experiments. In light of the tremendous effect of a background Fermi sea on two-body properties, a natural question is whether a background can modify or even destroy the Efimov effect. Here we demonstrate how the generic problem of three interacting particles changes when one particle is embedded in a background Fermi sea, and show that Efimov scaling persists. It is found in a scaling that relates the three-body physics to the background density of fermionic particles.Comment: 15 pages, 2 figures, 2 appendices, revised and updated version, in pres