Aspirations, Expectations and Education Outcomes for Children in Britain: Considering Relative Measures of Family Efficiency

We apply the distance function methodology to the analysis of household production functions. In particular, the family’s ability to efficiently and simultaneously generate a dual education (mathematics and reading) output for their child subject to multiple, constrained input availability is addressed. A stochastic production frontier model is estimated and significant shortfalls from the productive ideal are established, indicating that there is substantial scope for improvement in the production of childhood education outcomes amongst British families. There is also substantial variation across families in the efficiency of their production. Implementing a conditional mean model, inefficiency is shown to be strongly related to both family and child-centric variables and, in particular, to the educational aspirations of the parents for their child.childhood education, family, performance, production efficiency, aspirations, expectations

Robust signatures of quantum radiation reaction in focused ultrashort laser pulses

Radiation reaction effects in the interaction of an electron bunch with a superstrong focused ultrashort laser pulse are investigated in the quantum radiation dominated regime. The angle-resolved Compton scattering spectra are calculated in laser pulses of variable duration using a semi-classical description for the radiation dominated dynamics and a full quantum treatment for the emitted radiation. In dependence of the laser pulse duration we find signatures of quantum radiation reaction in the radiation spectra, which are characteristic for the focused laser beam and visible in the qualitative behaviour of both the angular spread and the spectral bandwidth of the radiation spectra. The signatures are robust with respect to the variation of the electron and laser beam parameters in a large range. They fully differ qualitatively from those in the classical radiation reaction regime and are measurable with presently available laser technology

Single-shot determination of spin-polarization for ultrarelativistic electron beams via nonlinear Compton scattering

Impacts of spin-polarization of an ultrarelativistic electron beam head-on colliding with a strong laser pulse on emitted photon spectra and electron dynamics have been investigated in the quantum radiation regime. We simulate photon emissions quantum mechanically and electron dynamics semiclassically via taking spin-resolved radiation probabilities in the local constant field approximation. A small ellipticity of the laser field brings about an asymmetry in angle-resolved photon spectrum, which sensitively relies on the polarization of the electron beam. The asymmetry is particularly significant in high-energy photon spectra, and is employed for the polarization detection of a high-energy electron beam with extraordinary precision, e.g., better than 0.3\% for a few-GeV electron beam at a density of the scale of $10^{16}$ cm$^{-3}$ with currently available strong laser fields. This method demonstrates for the first time a way of single-shot determination of polarization for ultrarelativistic electron beams via nonlinear Compton scattering. A similar method based on the asymmetry in the electron momentum distribution after the interaction due to spin-dependent radiation reaction is proposed as well

Electron-Angular-Distribution Reshaping in Quantum Radiation-Dominated Regime

Dynamics of an electron beam head-on colliding with an ultraintense focused ultrashort circularly-polarized laser pulse are investigated in the quantum radiation-dominated regime. Generally, the ponderomotive force of the laser fields may deflect the electrons transversely, to form a ring structure on the cross-section of the electron beam. However, we find that when the Lorentz factor of the electron $\gamma$ is approximately one order of magnitude larger than the invariant laser field parameter $\xi$, the stochastic nature of the photon emission leads to electron aggregation abnormally inwards to the propagation axis of the laser pulse. Consequently, the electron angular distribution after the interaction exhibits a peak structure in the beam propagation direction, which is apparently distinguished from the "ring"-structure of the distribution in the classical regime, and therefore, can be recognized as a proof of the fundamental quantum stochastic nature of radiation. The stochasticity signature is robust with respect to the laser and electron parameters and observable with current experimental techniques

Postpartum Contraception and Rapid Repeat Pregnancies in Rural, Low-Income Black Women with Baseline Risk Factor Comparisons

INTRODUCTION: The residents in the Low Country region of South Carolina consist of a predominantly low-income, African American population with a history of trauma and experiences of racism. Chronic conditions, unintended pregnancies, and adverse birth outcomes are prevalent. Many women experience rapid repeat pregnancies (RRP) due to lack of access to choices in contraceptive methods or lack of education on the dangers of RRP and prevention through contraception. Low Country Healthy Start (LCHS) aims to ensure that perinatal women and adolescents in the service area who enrolled received adequate prenatal and postpartum care, educational and counseling services, and contraceptive methods, including a Depo Provera injection at discharge (D1) after their index birth in LCHS. Previous research agree that black women, adolescents, low education, mental health, and past trauma are all associated with RRP, and lack adolescents are less likely to retain a form of contraception that requires maintenance and proper usage. AIM: To (1) examine the effect of D1 and other variables on time to RRP; and to (2) examine the effect of receiving various forms of contraception and their use over time, including the Depo injection (D2) on time to RRP. METHODS: Clients included in the analysis either delivered a baby while enrolled in LCHS or had complete data on all necessary variables (n=761). The Cox regression model was fitted to model the effect of receiving different contraceptive methods as well as relevant and statistically significant (α=0.05) risk factors on time to RRP. RESULTS: For Aim 1, D1 resulted in a hazard rate about 46% lower than that of a non-D1 (unadjusted HR = 0.54, 95% CI: 0.36- 0.83; adjusted HR = 0.52, 95% CI: 0.34-0.8). However, after adjusting for other variables (age, unplanned index pregnancy, physical abuse during pregnancy, and postpartum depression score) and the time-varying effect of D1, D1 resulted in a HR of 29.63 (β = 3.39, 95% CI: 6.049- 145.141), that decreased at a natural log function of time (HR = 0.22, β = -1.53, 95% CI: 0.12-0.40). For Aim 2, D2 resulted in a lower hazard rate than non-D2 (unadjusted HR = 0.17, 95% CI: 0.09-0.32; adjusted HR = 0.16, 95% CI: 0.08-0.31). Adjusting all variables in Aim 2, including D2, D1 resulted in a statistically insignificant lower HR of 0.88 (p = 0.544, 95% CI: 0.57-1.34). There was no significant interaction between D1and D2 or between D1 and any other contraceptive type. LARC showed a highly protective but not statistically significant effect against RRP (adjusted HR = 0.05, p = 0.093, 95% CI: 0.002-2.26), but that protective effect decreased multiplicatively by about .25 with each passing month (HR = 1.25, p = 0.029, 95% CI: 1.02-1.53). DISCUSSION: These findings indicate that the Depo injection, although important to receive at discharge, must be continued consistently to have a significant protective effect in preventing a RRP. LARC methods in general are strong protective factors. Being issued a contraceptive method that required adherence predicted a shorter inter-pregnancy interval (IPI), but this reflects the client’s adherence to the contraceptive method, and not its biological effectiveness. Future research should examine the effect of receiving the Depo injection at discharge on the continuation of different contraceptive methods, as well as the effect of counseling and educational services on contraceptive use and time to RRP

Ultrarelativistic polarized positron jets via collision of electron and ultraintense laser beams

Relativistic spin-polarized positron beams are indispensable for future electron-positron colliders to test modern high-energy physics theory with high precision. However, present techniques require very large scale facilities for those experiments. We put forward a novel efficient way for generating ultrarelativistic polarized positron beams employing currently available laser fields. For this purpose the generation of polarized positrons via multiphoton Breit-Wheeler pair production and the associated spin dynamics in single-shot interaction of an ultraintense laser pulse with an ultrarelativistic electron beam is investigated in the quantum radiation-dominated regime. A specifically tailored small ellipticity of the laser field is shown to promote splitting of the polarized particles along the minor axis of laser polarization into two oppositely polarized beams. In spite of radiative de-polarization, a dense positron beam with up to about 90\% polarization can be generated in tens of femtoseconds. The method may eventually usher high-energy physics studies into smaller-scale laser laboratories