<pre>El gobierno colombiano impulsa una política nacional para fortalecer las competencias comunicativas en inglés en todos los niveles educativos, en especial en la educación superior, pero poco se ha escrito sobre los logros de esa política. Este artículo describe los cambios en la distribución del nivel de inglés entre el ingreso y la terminación de la educación superior. Los resultados muestran que hay una mejora, dado el paso a niveles más altos de calificación, y un aumento de la polarización.</pre><p><em> </em></p>
Background
The use of respiratory devices can mitigate the spread of diseases such as COVID-19 in community settings. We aimed to determine the effectiveness of closed face shields with surgical face masks to prevent SARS-CoV-2 transmission in working adults during the COVID-19 pandemic in Bogotá, Colombia.
Methods
An open-label non-inferiority randomized controlled trial that randomly assigned participants to one of two groups: the intervention group was instructed to wear closed face shields with surgical face masks, and the active control group was instructed to wear only surgical face masks. The primary outcome was a positive reverse transcription polymerase chain reaction test, IgG/IgM antibody test for SARS-CoV-2 detection, or both during and at the end of the follow-up period of 21 days. The non-inferiority limit was established at − 5%.
Results
A total of 316 participants were randomized, 160 participants were assigned to the intervention group and 156 to the active control group. In total, 141 (88.1%) participants in the intervention group and 142 (91.0%) in the active control group completed the follow-up. Primary outcome: a positive SARS-CoV-2 test result was identified in one (0.71%) participant in the intervention group and three (2.1%) in the active control group. In the intention-to-treat analysis, the absolute risk difference was − 1.40% (95% CI [− 4.14%, 1.33%]), and in the per-protocol analysis, the risk difference was − 1.40% (95% CI [− 4.20, 1.40]), indicating non-inferiority of the closed face shield plus face mask (did not cross the non-inferiority limit).
Conclusions
The use of closed face shields and surgical face masks was non-inferior to the surgical face mask alone in the prevention of SARS-CoV-2 infection in highly exposed groups. Settings with highly active viral transmission and conditions such as poor ventilation, crowding, and high mobility due to occupation may benefit from the combined use of masks and closed face shields to mitigate SARS-CoV-2 transmission.
Trial registration
ClinicalTrials.gov NCT04647305. Registered on November 30, 2020
In this paper we formulate a dynamic multi-unit auction model to characterize bidding behavior in hydro power dominated electricity markets. Our model implies that, in order to maximize expected profits, hydro producers will submit bid prices above its marginal production costs that account for the intertemporal opportunity cost of water and the expected strategic effects of bids on rivals' behavior. We test the predictions of our model against data of the Colombian electricity market, where hydro producers hold 63% of total installed capacity, and find evidence consistent with both dynamic and strategic behavior.
We develop and estimate a model of child care markets that endogenizes both demand and supply. On the demand side, families with a child make consumption, labor supply, and child-care decisions within a static, unitary household model. On the supply side, child care providers make entry, price, and quality decisions under monopolistic competition. Child development is a function of the time spent with each parent and at the child care center; these inputs vary in their impact. We estimate the structural parameters of the model using the 2003 Early Childhood Longitudinal Study, which contains information on parental employment and wages, child care choices, child development, and center quality. We use our estimates to evaluate the impact of several policies, including vouchers, cash transfers, quality regulations, and public provision. Among these, a combination of quality regulation and vouchers for working families leads to the greatest gains in average child development and to a large expansion in child care use and female labor supply, all at a relatively low fiscal cost.
El presente Acuerdo de Confidencialidad (el "Acuerdo") es suscrito el día __ de ________ de 20__, entre QUANTIL SAS una compañía debidamente constituida bajo las leyes de la República de Colombia, con domicilio en la ciudad de Bogotá D.C. NIT 900225936-1 y dirección en la carrera 7 No. 77-07 de la misma ciudad (en adelante "LA COMPAÑIA"); y _______________________, identificado con cédula de ciudadanía No. __________ de _______ con domicilio en la ciudad de _________ y dirección en ______________________ (en caso de ser persona jurídica "obrando en nombre y representación de la sociedad "_____________________" domiciliada en ___________, constituida por medio
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