Priorities and Preconditions for Successful Investment in Smallholder Agriculture in Sub-Saharan Africa

In the past couple of years, there has been resurgence in interest in smallholder agriculture as a potential driver for growth and poverty reduction in Sub-Saharan Africa. However, there remains considerable skepticism as to whether public investment in smallholder agriculture will lead to the desired growth and poverty reduction, given a general pessimism about "absorptive capacity" for (public) investment in Africa, the perception of failure of past agricultural investment and the observation that current conditions are unconducive to agricultural growth in Africa. This paper combines experiences of two UK-based NGOs dedicated to promoting smallholder agriculture and strengthening rural livelihoods in Africa with insights from academic literature on African agriculture and rural markets to set out an agenda for investment in smallholder agriculture in Africa. It identifies priorities for public investment, but also key issues related to "absorptive capacity" that need to be addressed if such investment is to succeed in generating agricultural growth and poverty reduction. Particular emphasis is placed on: a) investment in human and organisational capacity of smallholder farmers; b) investment in coordinated service provision to equip producers to respond to evolving market opportunities; c) the process of developing and implementing credible agricultural development strategies at both national and local level, and; d) reform of Ministries of Agriculture to support this process.International Development,

Associations between social risk factors and surgical site infections after colectomy and abdominal hysterectomy

Importance: Surgical site infection (SSI) is an important patient safety outcome. Although social risk factors have been linked to many adverse health outcomes, it is unknown whether such factors are associated with higher rates of SSI. Objectives: To determine whether social risk factors, including race/ethnicity, insurance status, and neighborhood income, are associated with higher rates of SSI after colectomy or abdominal hysterectomy, 2 surgical procedures for which SSI rates are publicly reported and included in pay-for-performance programs by Medicare and other groups. Design, Setting, and Participants: This cross-sectional study analyzed adults undergoing colectomy or abdominal hysterectomy, as captured in State Inpatient Databases for Arizona, Florida, Iowa, Massachusetts, Maryland, New York, and Vermont. Operations were performed in 2013 through 2014 at general acute care hospitals in the United States. Data analysis was conducted from October 2018 through June 2019. Exposures: Colectomy or hysterectomy. Main Outcomes and Measures: Postoperative complex SSI rates. Results: A total of 149 741 patients met the inclusion criteria, including 90 210 patients undergoing colectomies (mean [SD] age, 63.4 [15.6] years; 49 029 [54%] female; 74% white, 11% black, 9% Hispanic, and 5% other or unknown race/ethnicity) and 59 531 patients undergoing abdominal hysterectomies (mean [SD] age, 49.8 [11.8] years; 100% female; 52% white, 26% black, 14% Hispanic, and 8% other or unknown race/ethnicity). In the colectomy cohort, 34% had private insurance, 52% had Medicare, 9% had Medicaid, and 5% had other or unknown insurance or were uninsured; 24% were from the lowest quartile of median zip code income. In the hysterectomy cohort, 57% had private insurance, 16% had Medicare, 19% had Medicaid, and 3% had other or unknown insurance or were uninsured; 27% were from the lowest-income zip codes. Within 30 days of surgery, SSI rates were 2.55% for the colectomy cohort and 0.61% for the hysterectomy cohort. For colectomy, black race (adjusted odds ratio [AOR], 0.71; 95% CI, 0.61-0.82) was associated with lower odds of SSI, whereas Medicare (AOR, 1.25; 95% CI, 1.10-1.41), Medicaid (AOR, 1.23; 95% CI, 1.06-1.44), and low neighborhood income (AOR, 1.14; 95% CI, 1.01-1.29) were associated with higher odds of SSI. For hysterectomy, no social risk factors that were examined in this study had statistically significant associations with SSI after adjustment for clinical risk. Conclusions and Relevance: Inconsistent associations between social risk factors and SSIs were found. For colectomy, infection prevention programs targeting low-income groups may be important for reducing disparities in this postoperative outcome, and policy makers could consider taking social risk factors into account when evaluating hospital performance

Self Calibration of Tomographic Weak Lensing for the Physics of Baryons to Constrain Dark Energy

Numerical studies indicate that uncertainties in the treatment of baryonic physics can affect predictions for shear power spectra at a level that is significant for forthcoming surveys such as DES, SNAP, and LSST. Correspondingly, we show that baryonic effects can significantly bias dark energy parameter measurements. Eliminating such biases by neglecting information in multipoles beyond several hundred leads to weaker parameter constraints by a factor of approximately 2 to 3 compared with using information out to multipoles of several thousand. Fortunately, the same numerical studies that explore the influence of baryons indicate that they primarily affect power spectra by altering halo structure through the relation between halo mass and mean effective halo concentration. We explore the ability of future weak lensing surveys to constrain both the internal structures of halos and the properties of the dark energy simultaneously as a first step toward self calibrating for the physics of baryons. This greatly reduces parameter biases and no parameter constraint is degraded by more than 40% in the case of LSST or 30% in the cases of SNAP or DES. Modest prior knowledge of the halo concentration relation greatly improves even these forecasts. Additionally, we find that these surveys can constrain effective halo concentrations near m~10^14 Msun/h and z~0.2 to better than 10% with shear power spectra alone. These results suggest that inferring dark energy parameters with measurements of shear power spectra can be made robust to baryonic effects and may simultaneously be competitive with other methods to inform models of galaxy formation. (Abridged)Comment: 18 pages, 11 figures. Minor changes reflecting referee's comments. Results and conclusions unchanged. Accepted for publication in Physical Review

Measuring Energy Expenditure and Heart Rate during Maximum Aerobic Testing with the Apple Watch Series 7

Introduction: Wrist-worn devices such as the Apple Watch have emerged as technology for tracking physical activity. The aim of this research study is to analyze the Apple Watch Series 7 (AW7) with measurements of the maximum heart rate (MHR) and maximum energy expenditure (MEE) during a maximal aerobic capacity test on the treadmill. AW7 measurements will be compared to the Polar Heart Rate Monitor (Polar) and the PARVO Metabolic Cart (PARVO). Methods: 22 healthy and active subjects (mean ± SD: age 23.8 ± 4.0 years; BMI 23.0 ± 5.9 kg/m2 ) volunteered for the study. The subjects confirmed their activity, health status, and were measured for body composition and aerobic capacity. Results: No significant difference was found in MEE between PARVO (109.6 ± 41.7 kcal) and AW7 (98.7 ± 24.3 kcal) conditions; t(21)=1.5, p = 0.153. In addition, there was no significant difference in MHR between PARVO (186.2 ± 16.2 BPM) and AW7 (189.3 ± 8.5 BPM) conditions; t(21)=-0.9, p = 0.379. Conclusions: The main findings of this study show that the MEE as well as the MHR between the AW7 compared to the PARVO are not different

Brain abscess and stroke in children and adults with hereditary hemorrhagic telangiectasia: Analysis of a large national claims database

BACKGROUND AND OBJECTIVES: Hereditary hemorrhagic telangiectasia (HHT) is an inherited disease associated with pathogenic variants in transforming growth factor-β signaling pathway-related genes, resulting in abnormal vascular development in various organs. Brain arteriovenous malformations (AVMs) may lead to intracranial hemorrhage, and brain abscess or ischemic stroke may result from right to left shunting via pulmonary AVMs. We aimed to investigate the risk for these severe complications in both adults and children with HHT. METHODS: We conducted a case-control study among participants aged 1-64 years in the MarketScan Commercial (2006-2019) and Multistate Medicaid Databases (2011-2019). We identified cases with HHT using RESULTS: A total of 5,796 patients with HHT, of whom 588 were children (age younger than 16 years), were matched with 57,960 controls. There was an increased incidence of brain abscesses in HHT cases compared with controls, with an RR of 35.6 (95% CI 15.4-82.5). No brain abscesses were recorded in children aged 15 years or younger. Hemorrhagic strokes/subarachnoid hemorrhages were more common in HHT cases, with an RR of 4.01 (95% CI 2.8-5.7) in adults and 60.2 (95% CI 7.2-500.4) in children. Ischemic strokes were also more common in cases, with an RR of 3.7 (95% CI, 3.0-4.5) in adults and 70.4 (95% CI 8.7-572.3) in children. DISCUSSION: We observed a much higher incidence of severe CNS vascular complications in patients with HHT, particularly in children. Although a higher incidence of brain abscesses was noted in adult patients with HHT, no brain abscesses were recorded in children, a result that may be considered when surveillance recommendations for this population are revisited

Measuring the three-dimensional shear from simulation data, with applications to weak gravitational lensing

We have developed a new three-dimensional algorithm, based on the standard P$^3$M method, for computing deflections due to weak gravitational lensing. We compare the results of this method with those of the two-dimensional planar approach, and rigorously outline the conditions under which the two approaches are equivalent. Our new algorithm uses a Fast Fourier Transform convolution method for speed, and has a variable softening feature to provide a realistic interpretation of the large-scale structure in a simulation. The output values of the code are compared with those from the Ewald summation method, which we describe and develop in detail. With an optimal choice of the high frequency filtering in the Fourier convolution, the maximum errors, when using only a single particle, are about 7 per cent, with an rms error less than 2 per cent. For ensembles of particles, used in typical $N$-body simulations, the rms errors are typically 0.3 per cent. We describe how the output from the algorithm can be used to generate distributions of magnification, source ellipticity, shear and convergence for large-scale structure.Comment: 22 pages, latex, 11 figure

Weak gravitational lensing in the standard Cold Dark Matter model, using an algorithm for three-dimensional shear

We investigate the effects of weak gravitational lensing in the standard Cold Dark Matter cosmology, using an algorithm which evaluates the shear in three dimensions. The algorithm has the advantage of variable softening for the particles, and our method allows the appropriate angular diameter distances to be applied to every evaluation location within each three-dimensional simulation box. We investigate the importance of shear in the distance-redshift relation, and find it to be very small. We also establish clearly defined values for the smoothness parameter in the relation, finding its value to be at least 0.88 at all redshifts in our simulations. From our results, obtained by linking the simulation boxes back to source redshifts of 4, we are able to observe the formation of structure in terms of the computed shear, and also note that the major contributions to the shear come from a very broad range of redshifts. We show the probability distributions for the magnification, source ellipticity and convergence, and also describe the relationships amongst these quantities for a range of source redshifts. We find a broad range of magnifications and ellipticities; for sources at a redshift of 4, 97{1/2}% of all lines of sight show magnifications up to 1.3 and ellipticities up to 0.195. There is clear evidence that the magnification is not linear in the convergence, as might be expected for weak lensing, but contains contributions from higher order terms in both the convergence and the shear.Comment: 14 pages, LaTeX, 15 figures include

Primordial black hole merger rates: distributions for multiple LIGO observables

We have calculated the detectable merger rate of primordial black holes, as a function of the redshift, as well as the binary's mass ratio, total mass and chirp mass (observables that have not previously been explored in great detail for PBHs). We consider both the current and design sensitivity of LIGO and five different primordial black hole mass functions, as well as showing a comparison to a predicted astrophysical black hole merger rate. We show that the empirical preference for nearly equal-mass binaries in current LIGO/Virgo data can be consistent with a PBH hypothesis once observational selection effects are taken into account. However, current data do exclude some PBH mass distributions, and future data may be able to rule out the possibility that all observed BH mergers had a primordial origin