A Multi-Country Study of Inter-Generational Educational Mobility

This paper analyses intergenerational educational mobility using survey data for twenty countries. We find that a number of interesting patterns emerge. Estimating a measure of mobility as movement and an index of mobility as equality of opportunity we find that while these two measures are positively correlated, the correlation is far from perfect. Examining the link with educational inequality we find evidence which suggests an inverse relationship between mobility and inequality consistent with egalitarian theory. The relationship between mobility appears to be weak, high returns to education do not depress mobility, as some human capital theories would suggest. Mobility appears to be somewhat higher for men whereas equality is much the same for both sexes. There is evidence that mobility as equality of opportunity has risen consistent with modernization theory. There is no evidence that expansion of third level education has led to a fall in the penalty associated with having a low educated parent. Estimates of marginal mobility are quite different from average mobility.

First order plus frequency dependent delay modeling : new perspective or mathematical curiosity?

The first-order-plus-dead-time model (FOPDT) is a popular simplified representation of higher order dynamics. However, a well known drawback is the rapid decrease of the frequency response accuracy with increasing process order. This especially applies to the higher frequency range. Literature offers solutions by extending this three parameter model with more parameters. Here, a fractional dead time is proposed. As such, a Frequency-Dependent Delay (FDD) is introduced, which offers a better approximation. As the fractional-order term introduces nonlinear coupling between the phase and the magnitude of the process, the fitting of the function becomes an iterative process, so a constrained multi-objective optimization is needed. This novel model, first-order-plus-frequency-dependent-delay or FOPFDD is fitted on a real electrical ladder network of resistors and capacitors of four and eight parts. The classic model, which is clearly a special case of the new model, is outperformed in the entire bandwidth

Efficient Mobile Edge Computing for Mobile Internet of Thing in 5G Networks

We study the off-line efficient mobile edge computing (EMEC) problem for a joint computing to process a task both locally and remotely with the objective of minimizing the finishing time. When computing remotely, the time will include the communication and computing time. We first describe the time model, formulate EMEC, prove NP-completeness of EMEC, and show the lower bound. We then provide an integer linear programming (ILP) based algorithm to achieve the optimal solution and give results for small-scale cases. A fully polynomial-time approximation scheme (FPTAS), named Approximation Partition (AP), is provided through converting ILP to the subset sum problem. Numerical results show that both the total data length and the movement have great impact on the time for mobile edge computing. Numerical results also demonstrate that our AP algorithm obtain the finishing time, which is close to the optimal solution

Active learning in control education : a pocket-size PI(D) setup

Active learning techniques have the possibility to enhance student performance. In control engineering these techniques unravel concepts such as feedback control, proportional-integral-derivative control, system dynamics, etc. This paper presents the development of pocket-size PID setups and how they are implemented in an undergraduate course of control engineering. The setup makes use of an electrical circuit which has the capability of mimicking a wide range of processes, thus appealing to the multidisciplinary character of the student group. Custom-made analog PID printed circuit boards are developed, making each part of the controller transparent. Open-source software is used to build a graphical user interface to communicate with data-acquisition cards used in industry. It is shown in this paper that investing in mobile setups which are numerous, allows for active learning in control education. This leads to better understanding of abstract concepts and increased student performance

Distributional Impacts of Retail Vaccine Availability

We examine the potential for exploiting retailer location choice in targeting health interventions. Using geospatial data, we quantify proximity to vaccines created by a U.S. federal program distributing COVID-19 vaccines to commercial retail pharmacies. We assess the distributional impacts of a proposal to provide vaccines at Dollar General, a low-priced general merchandise retailer. Adding Dollar General to the federal program would substantially decrease the distance to vaccine sites for low-income, rural, and minority U.S. households, groups for which COVID-19 vaccine take-up has been disproportionately slow

Mapping High-velocity H-alpha and Lyman-alpha Emission from Supernova 1987A

We present new {\it Hubble Space Telescope} images of high-velocity H-$\alpha$ and Lyman-$\alpha$ emission in the outer debris of SN~1987A. The H-$\alpha$ images are dominated by emission from hydrogen atoms crossing the reverse shock. For the first time we observe emission from the reverse shock surface well above and below the equatorial ring, suggesting a bipolar or conical structure perpendicular to the ring plane. Using the H$\alpha$ imaging, we measure the mass flux of hydrogen atoms crossing the reverse shock front, in the velocity intervals ($-$7,500~$<$~$V_{obs}$~$<$~$-$2,800 km s$^{-1}$) and (1,000~$<$~$V_{obs}$~$<$~7,500 km s$^{-1}$), $\dot{M_{H}}$ = 1.2~$\times$~10$^{-3}$ M$_{\odot}$ yr$^{-1}$. We also present the first Lyman-$\alpha$ imaging of the whole remnant and new $Chandra$ X-ray observations. Comparing the spatial distribution of the Lyman-$\alpha$ and X-ray emission, we observe that the majority of the high-velocity Lyman-$\alpha$ emission originates interior to the equatorial ring. The observed Lyman-$\alpha$/H-$\alpha$ photon ratio, $\langle$$R(L\alpha / H\alpha)$$\rangle$ $\approx$~17, is significantly higher than the theoretically predicted ratio of $\approx$ 5 for neutral atoms crossing the reverse shock front. We attribute this excess to Lyman-$\alpha$ emission produced by X-ray heating of the outer debris. The spatial orientation of the Lyman-$\alpha$ and X-ray emission suggests that X-ray heating of the outer debris is the dominant Lyman-$\alpha$ production mechanism in SN 1987A at this phase in its evolution.Comment: 6 pages, 5 figures. ApJL - accepte

Gamma-Ray Burster Counterparts: HST Blue and Ultraviolet Data

The surest solution of the Gamma Ray Burst (GRB) mystery is to find an unambiguous low-energy quiescent counterpart. However, to date no reasonable candidates have been identified in the x-ray, optical, infrared, or radio ranges. The Hubble Space Telescope (HST) has now allowed for the first deep ultraviolet searches for quiescent counterparts. This paper reports on multiepoch ultraviolet searches of five GRB positions with HST. We found no sources with significant ultraviolet excesses, variability, parallax, or proper motion in any of the burst error regions. In particular, we see no sources similar to that proposed as a counterpart to the GRB970228. While this negative result is disappointing, it still has good utility for its strict limits on the no-host-galaxy problem in cosmological models of GRBs. For most cosmological models (with peak luminosity 6X10^50 erg/s), the absolute B magnitude of any possible host galaxy must be fainter than -15.5 to -17.4. These smallest boxes for some of the brightest bursts provide the most critical test, and our limits are a severe problem for all published cosmological burst models.Comment: 15 pages, 2 ps figures, accepted for publication in the Astrophysical Journa