Gender Segregation in Education: Evidence From Higher Secondary Stream Choice in India

This paper investigates gender-based segregation across different fields of study at the senior secondary level of schooling in a large developing country. We use a nationally representative longitudinal data set from India to analyze the extent and determinants of gender gap in higher secondary stream choice. Using fixed-effects regressions that control for unobserved heterogeneity at the regional and household levels, we find that girls are about 20 percentage points less likely than boys to study in science (STEM) and commerce streams as compared with humanities. This gender disparity is unlikely to be driven by gender-specific differences in cognitive ability, given that the gap remains large and significant even after we control for individuals' past test scores. We establish the robustness of these estimates through various sensitivity analyses: including sibling fixed effects, considering intrahousehold relationships among individuals, and addressing sample selection issues. Disaggregating the effect on separate streams, we find that girls are most underrepresented in the study of science. Our findings indicate that gender inequality in economic outcomes, such as occupational segregation and gender pay gaps, is determined by gendered trajectories set much earlier in the life course, especially at the school level.

Biomonitoring of water genotoxicity in a Conservation Unit in the Sinos River Basin, Southern Brazil, using the Tradescantiamicronucleus bioassay

<p>The <italic>Tradescantia</italic> micronucleus (Trad-MCN) bioassay was used to investigate genotoxicity of water bodies in the Parque Municipal Henrique Luís Roessler (PMHLR), a conservation unit in the city of Novo Hamburgo, Southern Brazil, from November 2010 to October 2011. Every month, cuttings with young inflorescences of <italic>Tradescantia pallida</italic> var. <italic>purpurea</italic> were exposed for 24 hours to water collected at three sites in the park: (S1) head of the main stream; (S2) head of a secondary stream; (S3) a point past the junction of the two water bodies in which S1 and S2 were located. As a negative control, cuttings were exposed to distilled water for 24 h every quarter. Micronuclei (MCN) frequency was determined in young tetrads of pollen mother cells and described as MCN/100 tetrads. Rainfall data were also recorded. In nine months at S1 and S2, and in eleven months at S3, micronuclei frequencies were significantly higher than in quarterly controls, in which frequencies varied from 1.19 to 1.62.</p><p>During sampling, no significant differences were found in MCN frequencies at S1, which ranged from 2.2 to 3.6. At the other sampling sites, there were significant differences between the months evaluated, and MCN frequencies ranged from 1.3 to 6.5 at S2 and from 2.3 to 5.2 at S3. There were no associations between rainfall and MCN frequencies at the three sampling sites. <italic>Tradescantia pallida</italic> var. <italic>purpurea</italic>confirmed genotoxicity in the water bodies of the PMHLR, even at the head of the streams, which suggests that actions should be promoted to control anthropogenic effects in the streams of this conservation unit.</p>

Study of Sound Generated by Large-Scale Structures in Low Speed Coaxial Jets

Sound generation by low speed circular and elliptic coaxial jets is investigated computationally. The secondary to primary jet velocity ratio is limited up to 0.4 and the elliptic jet profile has a 2:1 aspect ratio. Large Eddy Simulations are coupled with the Lighthill's acoustic analogy. Flow incompressibility is assumed limiting the study to the compact quadrupole structures generated during the jet mixing process. As expected, adding a secondary stream is found to extend the mixing region, while changing the jet geometry from circular to elliptic leads to vice versa. Good qualitative agreement in the flow behaviour is achieved with known results. Lighthill's longitudinal streamwise quadrupole is found to dominate the sound generation leading to a mildly high streamwise emission. Increasing the velocity ratio of the secondary stream to the primary stream increases the dominance of the streamwise sound emission. Good qualitative agreement with a previously suggested sound directivity pattern is achieved. Adding a secondary stream to the jet is found to have a mixed effect on the emitted acoustic power. A plausible explanation based on a large scale instability wave model is presented. Dominance of the longitudinal streamwise quadrupole Qxx was observed in all jets and the lateral quadrupoles Qxy and Qxz were of about the same magnitude and only secondary to Qxx. This resulted in high sound emission in the streamwise direction particularly as U1 /U0 was increased to 0.4. Good qualitative agreement was found with a previously suggested expression for the sound directivity pattern [18]. Adding a secondary stream did not cause a significant reduction in the overall acoustic power output as changing the jet geometry from circular to elliptic which was also limited to about 2 dB reduction. Further evidence for the existence of a large scale wave packet structure in the mixing region was produced. The wave packet source model was used to point to the opposing effects on the acoustic power output when adding a secondary stream, which could result in its mild and mixed effect.

Energy Recovery Proposals in an Ammonia/Water System for Power/Refrigeration Cogeneration

The authors proposed an ammonia-water cycle for power and refrigeration cogeneration which employs a splitting and absorption unit to adjust the desired solution concentrations. Energy efficiency and exergy efficiency of this cycle are found to be 27.3% and 57.6%, respectively, at the cycle highest heat addition conditions of 450°C /111bar. Nevertheless, a large exergy destruction takes place in the heat transfer and throttling process of this cycle. In this paper, three proposals are investigated to recover the energy of the heat transfer and throttling process. The weak ammonia/water solution is superheated by internal heat recovery, and then its energy is converted into useful outputs by: 1) sending the superheated ammonia-weak stream into the turbine, and the energy is directly converted into the power output: 2) and 3) introducing an ejector to the cycle, the superheated stream is used as the primary stream, the turbine exhaust and the evaporator outlet stream are used as the secondary stream, respectively, the energy is indirectly convert into power or refrigeration output. Simulations show that the three proposals enable the increments of 2.9%, 0.8% and 0.7%, respectively, in the exergy efficiency over the base cycle. Obviously, the first proposal has superiority in term of the thermal performance, while the latter two proposals have some advantages in respect of the operation, maintenance and capital costs.

An experimental study of underexpanded sonic, coaxial, swirl jets

The present study addresses experimental investigations of the near-field flow structures of an underexpanded sonic, dual, coaxial, swirl jet. The swirl stream is discharged from the secondary annular nozzle and the primary inner nozzle provides the underexpanded free jets. The interactions between the secondary swirl and primary underexpanded jets are quantified by a fine pitot impact and static pressure measurements and are visualized using a shadowgraph optical method. The pressure ratios of the secondary swirl and primary underexpanded jets are varied below 7.0. Experiments are conducted to investigate the effects of the secondary swirl stream on the primary underexpanded jets, compared with the secondary stream of no swirl. The results show that the presence of an annular swirl stream causes the Mach disc to move further downstream, with an increased diameter, and remarkably reduces the fluctuations of the impact pressures in the underexpanded sonic dual coaxial jet, compared with the case of the secondary annular stream with no swirl.