3,792 research outputs found

    The Impact of Poor Health on Total Factor Productivity

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    A number of recent studies have illustrated the link between health and growth (Gallup and Sachs 2000, McCarthy et al. 2000, Bhargava et al. 2000). This paper argues that a key mechanism through which health affects growth is via total factor productivity (TFP). We first estimate TFP based on a production function and then estimate the determinants of TFP, paying particular attention to three indicators of health that are particularly problematic in developing regions: malnutrition, malaria and waterborne diseases. We find the impact of poor health on TFP to be negative, significant, and robust across a wide variety of specifications.Total factor productivity, disease, health, underdevelopment

    Do southern Africa’s dominant-party systems affect popular attitudes?

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    Among the most distinctive features of Southern African politics is the region’s preponderance of one-party dominant systems. Considerable effort has been made to explain the unusual phenomenon with some analysts emphasizing the potential of such imbalances of power to undermine the effectiveness of a democracy’s institutions. However, political science has only just begun to study the repercussions the status quo may have for political culture in the region. Using survey data collected across the continent, this paper shifts the focus to this unexplored link between dominance and culture, aiming to shed some light on the relationship by studying the effect dominant party systems have on three specific political attitudes in Africa: demand for democracy, evaluation of the supply of democracy, and pluralism. The academic literature on Southern Africa’s dominant party systems has produced a theoretical distinction between two types of dominance. On the one hand is simple dominance, characterized only by long-term electoral success by a single party. On the other hand is dominance by parties who emerged from national liberation movements. Some analysts have argued that the ideological orientation of liberation parties and their unique claim to the right to rule renders them incompatible with essential features of democracy. This paper investigates the possibility that these distinct varieties of dominance have distinct effects on political attitudes. The results of the analyses conducted here offer strong evidence that dominant party systems do have implications for mass attitudes. Further, this research finds strong support for the argument that the nature of a party’s dominance matters, as means comparisons and regression analyses showed that the effects of dominance on popular attitudes were considerably stronger in systems where the dominant party was descended from a national liberation movement

    Relationship Between Quantitative MRI Biomarkers and Patient-Reported Outcome Measures After Cartilage Repair Surgery: A Systematic Review.

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    Background:Treatment of articular cartilage injuries remains a clinical challenge, and the optimal tools to monitor and predict clinical outcomes are unclear. Quantitative magnetic resonance imaging (qMRI) allows for a noninvasive biochemical evaluation of cartilage and may offer advantages in monitoring outcomes after cartilage repair surgery. Hypothesis:qMRI sequences will correlate with early pain and functional measures. Study Design:Systematic review; Level of evidence, 3. Methods:A PubMed search was performed with the following search terms: knee AND (cartilage repair OR cartilage restoration OR cartilage surgery) AND (delayed gadolinium-enhanced MRI OR t1-rho OR T2 mapping OR dgemric OR sodium imaging OR quantitative imaging). Studies were included if correlation data were included on quantitative imaging results and patient outcome scores. Results:Fourteen articles were included in the analysis. Eight studies showed a significant relationship between quantitative cartilage imaging and patient outcome scores, while 6 showed no relationship. T2 mapping was examined in 11 studies, delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) in 4 studies, sodium imaging in 2 studies, glycosaminoglycan chemical exchange saturation transfer (gagCEST) in 1 study, and diffusion-weighted imaging in 1 study. Five studies on T2 mapping showed a correlation between T2 relaxation times and clinical outcome scores. Two dGEMRIC studies found a correlation between T1 relaxation times and clinical outcome scores. Conclusion:Multiple studies on T2 mapping, dGEMRIC, and diffusion-weighted imaging showed significant correlations with patient-reported outcome measures after cartilage repair surgery, although other studies showed no significant relationship. qMRI sequences may offer a noninvasive method to monitor cartilage repair tissue in a clinically meaningful way, but further refinements in imaging protocols and clinical interpretation are necessary to improve utility

    Laser annealing of amorphous/poly: Silicon solar cell material flight experiment

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    The preliminary design proposed for the microelectronics materials processing equipment is presented. An overall mission profile, description of all processing steps, analysis methods and measurement techniques, data acquisition and storage, and a preview of the experimental hardware are included. The goal of the project is to investigate the viability of material processing of semiconductor microelectronics materials in a micro-gravity environment. The two key processes are examined: (1) Rapid Thermal Annealing (RTA) of semiconductor thin films and damaged solar cells, and (2) thin film deposition using a filament evaporator. The RTA process will be used to obtain higher quality crystalline properties from amorphous/poly-silicon films. RTA methods can also be used to repair radiation-damaged solar cells. On earth this technique is commonly used to anneal semiconductor films after ion-implantation. The damage to the crystal lattice is similar to the defects found in solar cells which have been exposed to high-energy particle bombardment

    Progeny of Germ Line Knockouts of \u3cem\u3eASI2\u3c/em\u3e, a Gene Encoding a Putative Signal Transduction Receptor in \u3cem\u3eTetrahymena Thermophila\u3c/em\u3e, Fail to Make the Transition from Sexual Reproduction to Vegetative Growth

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    The ciliated protozoan Tetrahymena has two nuclei: a germ line micronucleus and a somatic macronucleus. The transcriptionally active macronucleus has about 50 copies of each chromosome. At sexual reproduction (conjugation), the parental macronucleus is degraded and new macronucleus develops from a mitotic product of the zygotic micronucleus. Development of the macronucleus involves massive genome remodeling, including deletion of about 6000 specific internal eliminated sequences (IES) and multiple rounds of DNA replication. A gene encoding a putative signal transduction receptor, ASI2, (anlagen stage induced 2) is up-regulated during development of the new macronuclei (anlagen). Macronuclear ASI2 is nonessential for vegetative growth. Homozygous ASI2 germ line knockout cells with wild type parental macronuclei proceed through mating but arrest at late macronuclear anlagen development and die before the first post-conjugation fission. IES elimination occurs in these cells. Two rounds of postzygotic DNA replication occur normally in progeny of ASI2 germ line knockouts, but endoreduplication of the macronuclear genome is arrested. The germ line ASI2 null phenotype is rescued in a mating of a knockout strain with wild type cells

    Sarcoidosis presenting as granulomatous myositis in a 16-year-old adolescent

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    BACKGROUND: Sarcoidosis is a multi-system disease characterized by the presence of non-caseating epithelioid granulomas in affected tissues, including skeletal muscle. These organized collections of immune cells have important pathophysiologic action including cytokine production leading to inflammation as well as enzymatic conversion of cholecalciferol to calcitriol via 1-α hydroxylase. There are limited reports of isolated granulomatous myositis causing hypercalcemia in pediatric patients. Our patient uniquely presented with symptoms from hypercalcemia and renal insufficiency caused by an overwhelming burden of granulomatous myositis in her lower extremities, but was otherwise asymptomatic. CASE PRESENTATION: A 16 year old Caucasian female presented with protracted symptoms of fatigue, nausea and prominent weight loss with laboratory evidence of hypercalcemia and renal insufficiency. She lacked clinical and physical findings of arthritis, weakness, rash, uveitis, fever, lymphadenopathy or respiratory symptoms. After extensive negative investigations, re-examination yielded subtle soft tissue changes in her lower extremities, with striking MRI findings of extensive myositis without correlative weakness or serum enzyme elevation. Biopsy showed the presence of non-caseating epithelioid granulomas and calcium oxalate crystals. The patient responded well to prednisone and methotrexate but relapsed with weaning of steroids. She reachieved remission with addition of adalimumab. CONCLUSIONS: Sarcoidosis should be considered in patients presenting with symptomatic hypercalcemia with no apparent causes and negative routine workup. The absences of decreased muscle strength or elevated muscle enzymes do not preclude the diagnosis of granulomatous myositis

    Interim Monitoring of Sequential Multiple Assignment Randomized Trials Using Partial Information

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    The sequential multiple assignment randomized trial (SMART) is the gold standard trial design to generate data for the evaluation of multi-stage treatment regimes. As with conventional (single-stage) randomized clinical trials, interim monitoring allows early stopping; however, there are few methods for principled interim analysis in SMARTs. Because SMARTs involve multiple stages of treatment, a key challenge is that not all enrolled participants will have progressed through all treatment stages at the time of an interim analysis. Wu et al. (2021) propose basing interim analyses on an estimator for the mean outcome under a given regime that uses data only from participants who have completed all treatment stages. We propose an estimator for the mean outcome under a given regime that gains efficiency by using partial information from enrolled participants regardless of their progression through treatment stages. Using the asymptotic distribution of this estimator, we derive associated Pocock and O'Brien-Fleming testing procedures for early stopping. In simulation experiments, the estimator controls type I error and achieves nominal power while reducing expected sample size relative to the method of Wu et al. (2021). We present an illustrative application of the proposed estimator based on a recent SMART evaluating behavioral pain interventions for breast cancer patients

    Air pollution exposure and Covid‑19 in Dutch municipalities

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