Do student loans improve accessibility to higher education and student performance? An impact study of the SOFES program in Mexico

Financial aid to students in tertiary education can contribute to human capital accumulation through two channels: increased enrolment and improved student performance. We analyse the quantitative importance of both channels in the context of a student loan program (SOFES) implemented at private universities in Mexico. With regard to the first channel, results from the Mexican household survey indicate that financial support has a strongly positive effect on university enrolment. Two data sources are used to investigate the second channel, student performance. Administrative data provided by SOFES are analysed using a Regression-Discontinuity design, and survey data enable us to perform a similar analysis using a different control group. The empirical results suggest that SOFES recipients (i) show better academic performance, and (ii) tend to have more part-time jobs than students without a credit from SOFES.

Irregularity of bedform dimensions

Measured bed elevation profiles show that bedforms are far from regular. Even under controlled steady flow conditions in laboratory flumes bedforms are irregular in size, shape and spacing. Here we present a new Bedform Tracking Tool to determine the (stochastics of) bedform characteristics in an objective manner. This tool helps us in developing a model for variability in bedform dimensions. Form drag, i.e. the flow resistance that is attributed to the presence of bedforms, depends on bedform dimensions. We expect that by taking into account the variability in bedform dimensions the prediction of form drag will be improved. Present research focuses on the effects of variability in bedform dimensions upon form drag

Interacting Multiple Model-Feedback Particle Filter for Stochastic Hybrid Systems

In this paper, a novel feedback control-based particle filter algorithm for the continuous-time stochastic hybrid system estimation problem is presented. This particle filter is referred to as the interacting multiple model-feedback particle filter (IMM-FPF), and is based on the recently developed feedback particle filter. The IMM-FPF is comprised of a series of parallel FPFs, one for each discrete mode, and an exact filter recursion for the mode association probability. The proposed IMM-FPF represents a generalization of the Kalmanfilter based IMM algorithm to the general nonlinear filtering problem. The remarkable conclusion of this paper is that the IMM-FPF algorithm retains the innovation error-based feedback structure even for the nonlinear problem. The interaction/merging process is also handled via a control-based approach. The theoretical results are illustrated with the aid of a numerical example problem for a maneuvering target tracking application

Hard sphere colloidal dispersions: Mechanical relaxation pertaining to thermodynamic forces

The complex viscosity of sterically stabilized (hard) silica spheres in cyclohexane has been measured between 80 Hz and 170 kHz with torsion pendulums and a nickel tube resonator. The observed relaxation behaviour can be attributed to the interplay of hydrodynamic and thermodynamic forces. The validity of the Cox-Merz rule is checked

Parallel Recursive State Compression for Free

This paper focuses on reducing memory usage in enumerative model checking, while maintaining the multi-core scalability obtained in earlier work. We present a tree-based multi-core compression method, which works by leveraging sharing among sub-vectors of state vectors. An algorithmic analysis of both worst-case and optimal compression ratios shows the potential to compress even large states to a small constant on average (8 bytes). Our experiments demonstrate that this holds up in practice: the median compression ratio of 279 measured experiments is within 17% of the optimum for tree compression, and five times better than the median compression ratio of SPIN's COLLAPSE compression. Our algorithms are implemented in the LTSmin tool, and our experiments show that for model checking, multi-core tree compression pays its own way: it comes virtually without overhead compared to the fastest hash table-based methods.Comment: 19 page

Variations in roughness predictions (flume experiments)

Data of flume experiments with bed forms are used to analyze and compare different roughness predictors. In this study, the hydraulic roughness consists of grain roughness and form roughness. We predict the grain roughness by means of the size of the sediment. The form roughness is predicted by three approaches: Van Rijn (1984), Vanoni & Hwang (1967) and Engelund (1966). The total roughness values (friction factors) are compared with the roughness values according to the DarcyWeisbach equation. Results show that the different methods predict different friction factors. In future research uncertainties in the hydraulic roughness will be taken into account to determine their influence on the computed water levels

Sea Bed Sand Waves Studied To Help Pipeline Planners

The article cites a study that offers information on the variability of sand wave characteristics in the North Sea. The sand waves variability includes a statement that pipelines may start vibrating due to turbulence generated under the free span and navigational channels often need to be dredged for ships to pass safely. The study used multi-beam measurement of three fields in the North Sea in which sand waves occur. Moreover, the study concludes that understanding the variability of sand waves can help determine the optimal depth of a pipeline trench