Vertical motions in the disk of NGC 5668 as seen with optical Fabry-Perot spectroscopy

We have observed the nearly face-on spiral galaxy NGC 5668 with the TAURUS II Fabry-Perot interferometer at the William Herschel Telescope using the $H\alpha$ line to study the kinematics of the ionized gas. From the extracted data cube we construct intensity, velocity and velocity dispersion maps. We calculate the rotation curve in the innermost 2 arcmin and we use the residual velocity field to look for regions with important vertical motions. By comparing the geometry of these regions in the residual velocity field with the geometry in the intensity and velocity dispersion maps we are able to select some regions which are very likely to be shells or chimneys in the disk. The geometry and size of these regions are very similar to the shells or chimneys detected in other galaxies by different means. Moreover, it is worth noting than this galaxy has been reported to have a population of neutral hydrogen high velocity clouds (Schulman et al. 1996) which, according to these observations, could have been originated by chimneys similar to those reported in this paper.Comment: 7 pages with 9 figures. LaTeX file using A&A v4.0 macro

Radiatively Generated Isospin Violations in the Nucleon and the NuTeV Anomaly

Predictions of isospin asymmetries of valence and sea distributions are presented which are generated by QED leading ${\cal{O}}(\alpha)$ photon bremsstrahlung effects. Together with isospin violations arising from nonperturbative hadronic sources (such as quark and target mass differences) as well as with even a conservative contribution from a strangeness asymmetry ($s\neq \bar{s}$), the discrepancy between the large NuTeV `anomaly' result for $\sin^2\theta_W$ and the world average of other measurements is removed.Comment: 10 pages, 2 figure

The relative effectiveness of single-sex and coeducational schools in Thailand

This paper provides evidence regarding the relative effects of single-sex and coeducational school in enhancing eighth grade mathematics achievement in Thailand. It uses pre and post eighth grade test scores to estimate value added equations for single-sex and coeducational schools. The preliminary conclusions are the following. First, girls in single-sex schools do significantly better than their coeducational school counterparts, while boys in coeducational schools do better. Thus there is not a unique single-sex/coeducational school effect on enhancing achievement, but this effect interacts strongly according to the sex of the student. Second, it is expected that selection biases are mitigated in"value added"formulations of achievement functions (as opposed to"level"formulations), and they are still significant in Thailand. Third, even after measured inputs and school practices are held constant, a single sex school advantage for females and a coeducational school advantage for males persist. Finally, peer"quality"effects in single-sex and coeducational schools appear to account for most of the difference between the two types of schools and their relative effectiveness for male and female students.Gender and Education,Teaching and Learning,Adolescent Health,Health Monitoring&Evaluation,Primary Education

X.509 certificate error testing

X.509 Certificates are used by a wide range of technologies to verify identities, while the SSL protocol is used to provide a secure encrypted tunnel through which data can be sent over a public network. Combined both of these technologies provides the basis of the public key infrastructure (PKI). While the concept of PKI is a good idea, the different implementation of the technologies in different operating system and clients often lead to weaknesses. This paper proposes a methodology to automate the testing of SSL clients by generating both bogus and malformed certificates in order to evaluate the client’s response and identify potential threats to network infrastructures

Encoding algebraic power series

Algebraic power series are formal power series which satisfy a univariate polynomial equation over the polynomial ring in n variables. This relation determines the series only up to conjugacy. Via the Artin-Mazur theorem and the implicit function theorem it is possible to describe algebraic series completely by a vector of polynomials in n+p variables. This vector will be the code of the series. In the paper, it is then shown how to manipulate algebraic series through their code. In particular, the Weierstrass division and the Grauert-Hironaka-Galligo division will be performed on the level of codes, thus providing a finite algorithm to compute the quotients and the remainder of the division.Comment: 35 page

The relative efficiency of public schools in developing countries

With the demand for schooling expected to increase and the tightening of fiscal constraints, changes will be necessary in order to meet ambitious educational targets. Instead of charging fees for public schools, a more cost-effective option is to rely on private schools to handle the growing demand for education. Private school students generally out perform public school students on standardized math and language tests. This finding takes into account that private school students usually come from slightly more advantaged backgrounds than their public school counterparts. In addition, school expenditure data show that unit costs for private schools are dramatically lower than those of public schools. The comparative advantage of private schools has important policy implications for public schools. Some efficiency gains can come from replicating the input mix of private schools. Also effective would be to mimic the organizational incentive structures of private schools.Teaching and Learning,Health Monitoring&Evaluation,Gender and Education,Primary Education,Education Reform and Management

Social Protection of Older People

Social protection is a major arena of government activity aimed at ensuring that vulnerable population groups receive appropriate and effective public support to ensure their financial security and to safeguard their health. However, despite the growth and extent of social protection programs in both developed and developing countries, most emerging economies have nascent systems and only a small portion of all such efforts address the specific vulnerabilities and needs of older people. This paper (a) discusses the vulnerabilities of older people and the benefits of crafting social programs to address them; (b) describes the nature of social protection and the forms it can take to address those vulnerabilities; (c) reports descriptive evidence on the availability and use of social protection programs; and (d) delineates steps that can be taken to remedy the shortfalls experienced by older people.aging, social protection