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.

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

Causaliteit in het verzekeringsrecht

Sinds het begin van de 20e eeuw hebben juristen gezocht naar een theorie die in het kader van het strafrecht en de privaatrechtelijke onrechtmatige daad het richtsnoer zou moeten zijn voor het vereiste causaal verband tussen de verwijtbare gedraging en de schade. Uiteindelijk heeft dit voor het privaatrecht geresulteerd in de leer van de toerekening naar redelijkheid zoals opgenomen in artikel 6:98 BW. Ook in het verzekeringsrecht heeft men lange tijd gedacht aan een dergelijke verklarende theorie en overeenkomsten gezocht met causaliteit bij de onrechtmatige daad en in het strafrecht. De laatste decennia is echter het inzicht ontstaan dat voor het verzekeringsrecht andere principes voor het causaal verband gelden en voornoemde theorieën lijken slechts een bijrol te vervullen. Niet aan de orde is het zoeken naar een verband tussen een verwijtbare gedraging en de schade. Centraal staat de vraag of de verzekeraar op basis van polisbepalingen, met het eigen stelsel van gedekte en uitgesloten oorzaken – naast de grenzen die de wet daaraan stelt – gehouden is schade-uitkeringen aan de verzekerde te doen. Het verzekeringsrecht kent voor het antwoord op deze vraag een gecompliceerde systematiek die is gebaseerd op de betekenis van een aantal verzekeringsrechtelijke begrippen, uitleg van polisbepalingen en het beginsel van redelijkheid en billijkheid. Causaliteit neemt in deze systematiek een centrale positie in.The purpose of this dissertation is exploring the role of cause and causation in insurance law (indemnity). Cause and causatiom appear to play a central role in the system of coverage in insurance policies. Coverage and exceptions are formulated in causal wordings. That makes causation in insurance law different from causation in tort law and penal law. Whether or not circumstances are covered or excepted from coverage in insurance policies is a matter of construction of the policies. Despite this notion most insurance law literature has been influenced by socalled theories about causality in tort and penal law (conditio sine qua non, theory of adequacy and reasonable imputation). This dissertation consists of three parts. The first part deals with the meaning of ‘cause’ in the context of insurance policies. This term is, in a rather complex way, connected with several other terms which are, at least in part, typical for insurance law. The term ‘cause’ is compared with the terms ‘uncertain event’ (uncertainty), event, fortuitous event, inherent vice and wear and tear, damage and loss, accident, peril of the sea. There is a tendency to equalize uncertain event and cause. In my opinion these terms must be distinguished. Essential is the definition of ‘cause’ in insurance law, which is derived from a definition given to that term in tort law. Cause is a specific circumstance which differs from the normal course of events/things. This definition is useful because now circumstances which are relevant in a ‘causal’ sense can be separated from circumstances which are not relevant in this way. The second part deals with ‘causation’ as opposed to ‘cause’. To ascertain whether or not there is coverage, it is necessary to make a choice among various causes (covered and excepted) within the meaning of Part I. In case (one of the) parties put(s) forward a certain circumstance as the relevant (proximate) cause but the circumstance is not self-evident the court may put the burden of proof on one of the parties. This burden of proof can be decisive for the judgement. In other cases where several possible causes are known, the judge has to choose. According to Dutch insurance law the interpretation of the contract is decisive for the outcome of this choice. Furthermore several theories of causation are explored. Part three contains the subject ‘obligations of the insured’ (Obliegenheiten according to German law). May the insurer deny indemnification when non fulfillment of the obligations by the insured as stipulated in statute or contract does not have a causal relationship with the loss? Important case law is restricted to two subjects: non-disclosure/misrepresentation and alteration (aggravation) of the risk under the policy/warranties. In two chapters these subjects are described

Optically activated ZnO/Sio2/Si cantilever beams

The photomechanical effect induced by periodically varying sub-bandgap illumination in thin ZnO films deposited on oxidized Si has been demonstrated for the first time. The efficiency of this effect is at least one order of magnitude higher as compared to the photothermal activation of Si. Thus it can be considered as a powerful optical drive for resonant sensors. A phenomenological model of the mechanisms involved in the process is proposed. The optomechanical effect can also be used as a complementary method in determination of the surface state parameters of ZnO films