434 research outputs found

    An Empirical Illustration of Positive Stigma towards Child Labor

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    This empirical note complements the qualitative and theoretical research on positive household stigma towards child labor. We use data from Guatemala and two instruments for measuring stigma: a child's indigenous background and household head's childhood work experience. We then adopt binomial probit regression methods to illustrate that positive stigma has a large effect on child labor practices, and a modest effect on school enrollment.child labor, education, indigenous, stigma, Guatemala

    Technology, computers, and wages : evidence from a developing economy

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    Increasing returns to schooling and rising inequality are well documented for industrial countries and for some developing countries. The growing demand for skills is associated with recent technological developments. The authors argue that computers in the workplace represent one manifestation of these changes. Research in the United States and industrial countries documents a premium for computer use. But there is recent evidence suggesting that computer skills by themselves do not command a wage premium. The authors review the literature and use data from a survey of higher education graduates in Vietnam. The results support the unobserved heterogeneity explanation for computer wage premiums. They suggest that computers may make the productive workers even more productive. However, given the scarcity of computers in low-income countries, an operational strategy of increasing computer availability and skills would seem to offer considerable hope for increasing the incomes of the poor.Information Technology,General Technology,Educational Technology and Distance Education,ICT Policy and Strategies,Teaching and Learning,ICT Policy and Strategies,General Technology,Educational Technology and Distance Education,Teaching and Learning,Primary Education

    Risk-Averse Model Predictive Operation Control of Islanded Microgrids

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    In this paper we present a risk-averse model predictive control (MPC) scheme for the operation of islanded microgrids with very high share of renewable energy sources. The proposed scheme mitigates the effect of errors in the determination of the probability distribution of renewable infeed and load. This allows to use less complex and less accurate forecasting methods and to formulate low-dimensional scenario-based optimisation problems which are suitable for control applications. Additionally, the designer may trade performance for safety by interpolating between the conventional stochastic and worst-case MPC formulations. The presented risk-averse MPC problem is formulated as a mixed-integer quadratically-constrained quadratic problem and its favourable characteristics are demonstrated in a case study. This includes a sensitivity analysis that illustrates the robustness to load and renewable power prediction errors

    Extending Kernel PCA through Dualization: Sparsity, Robustness and Fast Algorithms

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    The goal of this paper is to revisit Kernel Principal Component Analysis (KPCA) through dualization of a difference of convex functions. This allows to naturally extend KPCA to multiple objective functions and leads to efficient gradient-based algorithms avoiding the expensive SVD of the Gram matrix. Particularly, we consider objective functions that can be written as Moreau envelopes, demonstrating how to promote robustness and sparsity within the same framework. The proposed method is evaluated on synthetic and real-world benchmarks, showing significant speedup in KPCA training time as well as highlighting the benefits in terms of robustness and sparsity.Comment: 15 pages, ICML 202

    Measuring human capital using global learning data

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    Human capital—that is, resources associated with the knowledge and skills of individuals—is a critical component of economic development1,2. Learning metrics that are comparable for countries globally are necessary to understand and track the formation of human capital. The increasing use of international achievement tests is an important step in this direction3. However, such tests are administered primarily in developed countries4, limiting our ability to analyse learning patterns in developing countries that may have the most to gain from the formation of human capital. Here we bridge this gap by constructing a globally comparable database of 164 countries from 2000 to 2017. The data represent 98% of the global population and developing economies comprise two-thirds of the included countries. Using this dataset, we show that global progress in learning—a priority Sustainable Development Goal—has been limited, despite increasing enrolment in primary and secondary education. Using an accounting exercise that includes a direct measure of schooling quality, we estimate that the role of human capital in explaining income differences across countries ranges from a fifth to half; this result has an intermediate position in the wide range of estimates provided in earlier papers in the literature5–13. Moreover, we show that average estimates mask considerable heterogeneity associated with income grouping across countries and regions. This heterogeneity highlights the importance of including countries at various stages of economic development when analysing the role of human capital in economic development. Finally, we show that our database provides a measure of human capital that is more closely associated with economic growth than current measures that are included in the Penn world tables version 9.014 and the human development index of the United Nations15

    The Hellenic type of nondeletional hereditary persistence of fetal hemoglobin results from a novel mutation (g.-109G>T) in the HBG2 gene promoter

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    Nondeletional hereditary persistence of fetal hemoglobin (nd-HPFH), a rare hereditary condition resulting in elevated levels of fetal hemoglobin (Hb F) in adults, is associated with promoter mutations in the human fetal globin (HBG1 and HBG2) genes. In this paper, we report a novel type of nd-HPFH due to a HBG2 gene promoter mutation (HBG2:g.-109G>T). This mutation, located at the 3′ end of the HBG2 distal CCAAT box, was initially identified in an adult female subject of Central Greek origin and results in elevated Hb F levels (4.1%) and significantly increased Gγ-globin chain production (79.2%). Family studies and DNA analysis revealed that the HBG2:g.-109G>T mutation is also found in the family members in compound heterozygosity with the HBG2:g.-158C>T single nucleotide polymorphism or the silent HBB:g.-101C>T β-thalassemia mutation, resulting in the latter case in significantly elevated Hb F levels (14.3%). Electrophoretic mobility shift analysis revealed that the HBG2:g.-109G>T mutation abolishes a transcription factor binding site, consistent with previous observations using DNA footprinting analysis, suggesting that guanine at position HBG2/1:g.-109 is critical for NF-E3 binding. These data suggest that the HBG2:g-109G>T mutation has a functional role in increasing HBG2 transcription and is responsible for the HPFH phenotype observed in our index cases

    Does quantitative heterogeneity of human fetal hemoglobin (Hb F) reveal friends or foes of KLF1 in globin gene switching?

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    The chemical heterogeneity of fetal hemoglobin (Hb F) due to variable ratios of the Gγ and Aγ globin subunits reflects genetic complexity because of common dimorphisms such as Hb F Sardegna (or Aγ75(E19) Ile>Thr; also known as AγT) in Caucasians, and common variants such the Gγ globin variant, Hb F Malta I (or Gγ117(G19) His>Arg) that is in tight linkage disequilibrium with the β globin variant Hb Valletta (or β87(F3) Thr>Pro) and is found in 1.8% of neonates from Malta.peer-reviewe
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