A metric of Yukawa potential as an exact solution to the field equations of general relativity

It is shown that, by defining a suitable energy momentum tensor, the field equations of general relativity admit a line element of Yukawa potential as an exact solution. It is also shown that matter that produces strong force may be negative, in which case there would be no Schwarzschild-like singularityComment: Latex 4 pages (some changes in notation, and a discussion on a repulsive term that may be related to the charge of a particle

Is Foreign Direct Investment Good for Growth? Evidence from Sectoral Analysis of China and Vietnam

We estimate the impact of FDI on growth using sectoral data for FDI inflows to China and Vietnam. Previous empirical studies, using either cross-country growth regressions or firm-level micro-econometric analysis, fail to reach a consensus. Our paper is the first to use sectoral FDI inflow data to evaluate the sector-specific impact of FDI on growth. Our results show that, for the two developing-transition economies we examine, FDI has a statistically-significant positive effect on economic growth operating directly and through its interaction with labor. Intriguingly, we find the effects seem to be very different across economic sectors, with almost all the beneficial impact limited to industrial sector. Other sectors appear to gain very little growth benefit from sector-specific FDI.Foreign direct investment, growth, China, Vietnam

Hitting Pause on Organic Chemistry

Written procedures for performing organic chemistry experiments are replaced by visual demonstrations that allow students to watch these videos at home and/ or in the laboratory. These previously recorded demonstrations allow students to watch, pause, and rewind the video to better understand laboratory techniques

Assessing alternative poverty proxy methods in rural Vietnam

This paper compares and contrasts the use of four "short-cut" methods for identifying poor households: the poverty probability method; ordinary least squares regressions; principal components analysis; and quantile regressions. After evaluating these four methods using two alternative criteria (total and balanced poverty accuracy) and representative household survey data from rural Vietnam, it is concluded that the poverty probability method-which can correctly identify around four-fifths of poor and non-poor households-is the most accurate "short-cut" method for measuring poverty for specific subpopulations, or in years when household surveys are not available. The performance of the poverty probability method was then tested with different poverty lines and using an alternative household survey, and found to be robus

Measuring gender norms about relationships in early adolescence : results from the global early adolescent study

Introduction: Gender norms are increasingly recognized as drivers of health and wellbeing. While early adolescence constitutes a critical window of development, there is limited understanding about how adolescents perceive gender relations across different cultural settings. This study used a mixed-method approach, grounded in the voices of young people around the world, to construct and test a cross-cultural scale assessing the perceptions of gender norms regulating romantic relationships between boys and girls in early adolescence. Methods: The study draws on the Global Early Adolescent study (GEAS), a study focusing on gender norms and health related outcomes over the course of adolescence in urban poor settings worldwide. In-depth interviews were first conducted among approximately 200 adolescents between 10-14 years in seven sites across 4 continents to identify common scripts guiding romantic relations in early adolescence. These scripts were then transformed into a multidimensional scale. The scale was tested among 120 adolescents in each of 14 GEAS sites, followed by a second pilot among 75 adolescents in six sites. We evaluated the psychometric criteria of each subscale using principal component analysis, and parallel analysis, followed by exploratory factor analysis to guide the selection of a more parsimonious set of items. Results: Results suggested a two-factor structure, consisting of an "adolescent romantic expectations" subscale and a "Sexual Double Standard" subscale. Both subscales yielded high internal validity in each site, with polychoric Cronbach alpha values above 0.70 with the exception of Kinshasa for the adolescent romantic expectations scale (0.64) and Hanoi for the sexual double standard scale (0.61). Conclusion: This study reveals common perceptions of gendered norms about romantic engagement in early adolescence, normative for both sexes, but socially valued for boys while devaluated for girls. The findings illustrate that social hierarchies of power in romantic relationships form early in adolescence, regardless of cultural setting

A CFD Analysis of Easterly Wind Flow Impacting the Vehicle Assembly Building

In an attempt to explain the high loss of panels from the south face of the Vehicle Assembly Building (VAB) during Hurricane Frances, a three-dimensional computational fluid dynamics (3-D CFD) model was developed to simulate local velocity and pressure distributions resulting from such a storm. A preconditioned compressible Navier-Stokes flow solver 1 was used to compute the flow field around the VAB complex, including the Launch Control Center, the Low and High Bays of the VAB, and several outbuildings in the immediate LC-39 area. The mapping of the forces and velocities on and along the affected faces of the VAB correlated surprisingly well with the extensive damage areas realized on both on the south face and on the southeast section of the roof. The model results were also consistent with the minimal damage seen on the east, north, and west faces of the structure