The effect of gender differences in primary school access, type, and quality on the decision to enroll in rural Pakistan

The paper explores the effect of primary school access, type, and quality on the decision to enroll in rural Pakistan using a 1997 survey especially designed for this purpose. A unique contribution of the paper is the construction of gender-specific dimensions of school accessibility and school quality according to school type (i.e., public vs. private). Within the same village, girls and boys often face starkly different options for schooling in terms of distance, type, and quality. Public primary schools are segregated by sex; private schools, whose numbers have grown rapidly in recent years in response to rising demand and the inadequate supply of public schools, are more typically mixed. The decision to enroll in school and the choice of school type are modeled simultaneously using a nested multinomial logit model. Simulations of alternative scenarios in terms of school access (measured as whether or not a primary school is located in the village), type, and quality are used to express our findings. The presence of a public school for girls in the village makes an enormous difference for girls in primary enrollment given parents’ reluctance for girls to travel far from home; for boys this is less of an issue because most villages have at least one public school for boys. We find that the addition of a private school option in a village that already has a public school has little impact on overall enrollment rates but rather leads to a redistribution of enrollment from public to private school. Girls’ enrollment in public primary is particularly responsive to improvements in some aspects of school quality, in particular whether or not the teacher resides in the village. This would suggest that school quality is important not only for retention but also for enrollment

Learning versus Working; Factors Affecting Adolescent Time Allocation in Pakistan

This paper explores how family, school and community factors influence adolescents’ time allocation among market work, domestic work, learning and leisure. We model adolescents’ time use in a multivariate framework, using explanatory variables characterising the household as well as labour demand, school access and school quality at the district level. This research shows that the amount of time children spend working, whether at home or in the market, is strongly correlated with household poverty, as proxied by an asset index. Consistent with the literature on the predictors of school enrolments of adolescents, the time spent on learning is also significantly lower among the poor. In Pakistan the Benazir Income Support Programme (BISP) census poverty score database, which includes information on household assets, would be a very promising tool to target efforts to increase children’s time allocated to learning. JEL classification: D60, I24, I30 Keywords: Pakistan, Education, Child Labour

Project PROMETHEUS: Design and Construction of a Radio Frequency Quadrupole at TAEK

The PROMETHEUS Project is ongoing for the design and development of a 4-vane radio frequency quadrupole (RFQ) together with its H+ ion source, a low energy beam transport (LEBT) line and diagnostics section. The main goal of the project is to achieve the acceleration of the low energy ions up to 1.5 MeV by an RFQ (352 MHz) shorter than 2 meter. A plasma ion source is being developed to produce a 20 keV, 1 mA H+ beam. Simulation results for ion source, transmission and beam dynamics are presented together with analytical studies performed with newly developed RFQ design code DEMIRCI. Simulation results shows that a beam transmission 99% could be achieved at 1.7 m downstream reaching an energy of 1.5 MeV. As the first phase an Aluminum RFQ prototype, the so-called cold model, will be built for low power RF characterization. In this contribution the status of the project, design considerations, simulation results, the various diagnostics techniques and RFQ manufacturing issues are discussed.Comment: 4 pages, 8 figures, Proceedings of the 2nd International Beam Instrumentation Conference 2013 (IBIC'13), 16-19 Sep 2013, WEPC02, p. 65

A plasma wakefield acceleration experiment using CLARA beam

We propose a Plasma Accelerator Research Station (PARS) based at proposed FEL test facility CLARA (Compact Linear Accelerator for Research and Applications) at Daresbury Laboratory. The idea is to use the relativistic electron beam from CLARA, to investigate some key issues in electron beam transport and in electron beam driven plasma wakefield acceleration, e.g. high gradient plasma wakefield excitation driven by a relativistic electron bunch, two bunch experiment for CLARA beam energy doubling, high transformer ratio, long bunch self-modulation and some other advanced beam dynamics issues. This paper presents the feasibility studies of electron beam transport to meet the requirements for beam driven wakefield acceleration and presents the plasma wakefield simulation results based on CLARA beam parameters. Other possible experiments which can be conducted at the PARS beam line are also discussed

Influence of steps on the tilting and adsorption dynamics of ordered Pn films on vicinal Ag(111) surfaces

Here we present a structural study of pentacene (Pn) thin films on vicinal Ag(111) surfaces by He atom diffraction measurements and density functional theory (DFT) calculations supplemented with van der Waals (vdW) interactions. Our He atom diffraction results suggest initial adsorption at the step edges evidenced by initial slow specular reflection intensity decay rate as a function of Pn deposition time. In parallel with the experimental findings, our DFT+vdW calculations predict the step edges as the most stable adsorption site on the surface. An isolated molecule adsorbs as tilted on the step edge with a binding energy of 1.4 eV. In addition, a complete monolayer (ML) with pentacenes flat on the terraces and tilted only at the step edges is found to be more stable than one with all lying flat or tilted molecules, which in turn influences multilayers. Hence our results suggest that step edges can trap Pn molecules and act as nucleation sites for the growth of ordered thin films with a crystal structure similar to that of bulk Pn.Comment: 4 pages, 4 figures, 1 tabl

High frequency and mesoscale variability in SeaWiFS chlorophyll imagery and its relation to other remotely sensed oceanographic variables, Deep Sea Res

Abstract In its typical use for the study of large scale and relatively slow variability of phytoplankton biomass, ocean-color imagery is often binned in space and in time, and variability within the bin is discarded as noise. Since small-to mesoscale processes at time scales as short as a day may play a significant role in global cycles of carbon and nutrients, characterizing variability at these scales is necessary. With the first four years of nearly continuous daily imagery from the SeaWiFS instrument, we investigated patterns of variability at the mesoscales, operationally defined as that within a 2 Â 2-degree neighborhood. We show that mesoscale variability of chlorophyll concentration (Chl) is high near the coasts, in dynamically active areas, and at the oligotrophic centers of subtropical gyres. High apparent variability over the oligotrophic ocean is a surprising contrast to the low variability in composite imagery at the same locations and may be due to increased relative noise at low mean Chl. Low correlation between pairs of images as little as 1 day apart in the oligotrophic ocean is consistent with a noise artifact, or alternatively may indicate that the observed variability is due to high-frequency phenomena. Spatial patterns of variability observed when data are binned into narrow ranges of mean Chl, suggest oceanographic origins. Patterns of variability in Chl and in sea-surface height have little correlation, suggesting that eddy pumping or turbulent diffusion along temporarily slanted isopycnal surfaces are not the major sources of Chl variability. The correlation between mesoscale anomalies of Chl and sea-surface temperature is not always negative as would have been the case if anomalies were produced mainly by the entrainment of colder, nutrientrich thermocline waters into the euphotic layer. Instead, we find roughly zonal bands of alternating negative and positive correlations determined by the relative directions of the background gradients of Chl and SST. Thus the most obvious influence of mesoscale motion on the distribution of Chl is advection of the existing gradients. Both long-term means and local anomalies of scatterometric winds from QuikSCAT are also correlated with mean Chl. Much of this correlation appears to be due to changes in the relationship between surface roughness and wind speed, brought on by factors like surface films, thermal stability of the air column, and surface currents. Our analyses show the feasibility of using ocean-color imagery to study mesoscale variability but also identify areas where there is room for major improvements. Minimization of speckling due to imperfect atmospheric correction, in particular, would significantly enhance the utility of SeaWiFS data at mesoscales

Observation of Faraday rotation from a single confined spin

Ability to read-out the state of a single confined spin lies at the heart of solid-state quantum information processing. While all-optical spin measurements using Faraday rotation has been successfully implemented in ensembles of semiconductor spins, read-out of a single semiconductor spin has only been achieved using transport measurements based on spin-charge conversion. Here, we demonstrate an all-optical dispersive measurement of the spin-state of a single electron trapped in a semiconductor quantum dot. We obtain information on the spin state through conditional Faraday rotation of a spectrally detuned optical field, induced by the polarization- and spin-selective trion (charged quantum dot) transitions. To assess the sensitivity of the technique, we use an independent resonant laser for spin-state preparation. An all-optical dispersive measurement on single spins has the important advantage of channeling the measurement back-action onto a conjugate observable, thereby allowing for repetitive or continuous quantum nondemolition (QND) read-out of the spin-state. We infer from our results that there are of order unity back-action induced spin-flip Raman scattering events within our measurement timescale. Therefore, straightforward improvements such as the use of a solid-immersion lens and higher efficiency detectors would allow for back-action evading spin measurements, without the need for a cavity