The Importance of Education in Future Population. Global Trends and Case Studies on Cape Verde, Sudan, and Tunisia

Education is a central issue in the complex process of development, for it has been found to be related to fertility and hence population growth, to the status of women, to labor force skills, as well as to cultural and infrastructural development in general. This paper consists of two main parts. The first examines the role of education and reviews school enrollment patterns in the world during the last 30 years. We deduce from this review some general patterns of enrollment increase and gender differential. The second part presents multi-state population projections by educational level and the resulting adult educational attainment, fertility levels and population growth. This is done through three case studies on the countries of Cape Verde, Sudan and Tunisia. The projection exercise shows some important dynamics of education and fertility change. The benefits to countries who have taken great strides to increase enrollment with superficially disappointing results to date will become obvious in the future. This may lead to some unexpected fertility declines and other changes associated with higher education. Adult levels of education have a long momentum and education increases in the adult population are non-linear. This is an important aspect when defining scenarios for future population growth

All conformally flat pure radiation metrics

The complete class of conformally flat, pure radiation metrics is given, generalising the metric recently given by Wils.Comment: 7 pages, plain Te

One year E-learning at the K.U.Leuven: an Examination of Log-Files

At the K.U.Leuven the introduction of a digital learning environment was strongly embedded in an already present and extensively communicated educational concept (‘guided independent learning’). Hence, it seems obvious that courses designed within the digital learning environment will be in line with this educational concept. An examination of logfiles however suggests that this might only be true for a minority of courses.In: A.J. Kallenberg and M.J.J.M. van de Ven (Eds), 2002, The New Educational Benefits of ICT in Higher Education: Proceedings. Rotterdam: Erasmus Plus BV, OECR ISBN 90-9016127-

V371 Per - A Thick-Disk, Short-Period F/1O Cepheid

V371 Per was found to be a double-mode Cepheid with a fundamental mode period of 1.738 days, the shortest among Galactic beat Cepheids, and an unusually high period ratio of 0.731, while the other Galactic beat Cepheids have period ratios between 0.697 and 0.713. The latter suggests that the star has a metallicity [Fe/H] between -1 and -0.7. The derived distance from the Galactic Plane places it in the Thick Disk or the Halo, while all other Galactic beat Cepheids belong to the Thin Disk. There are indications from historical data that both the fundamental and first overtone periods have lengthened.Comment: Accepted for publication in MNRA

The Unique Frequency Spectrum of the Blazhko RRc Star LS Her

The Blazhko effect in RR Lyrae stars is still poorly understood theoretically. Stars with multiple Blazhko periods or in which the Blazhko effect itself varies are particularly challenging. This study investigates the Blazhko effect in the RRc star LS Her. Detailed VRI CCD photometry has been performed on 63 nights during six months. LS Her is confirmed to have a Blazhko period of 12.75+/-0.02 days. However, where normally the side frequencies of the Blazhko triplet are expected, an equidistant group of three frequencies is found on both sides of the main pulsation frequency. As a consequence the period and amplitude of the Blazhko effect itself vary in a cycle of 109+/-4 days. LS Her is a unique object turning out to be very important in the verification of the theories for the Blazhko effect.Comment: Accepted for publication in MNRA

A campus wide setup of Question Mark Perception (V2.5) at the Katholieke Universiteit Leuven (Belgium) – facing a large scale implementation

The first part of this paper outlines the drawbacks of a large scale implementation of Question Mark Perception’s assessment software (QMP). The default publishing procedures offered by QMP, i.e. ODBC or disk sharing, do not meet the needs of global Internet accessibility and security. Academic staff members had to upload their session files by completing a web form; publishing requests were handled manually by members of the Computing Center’s staff. As on the server side all question and session records were stored in one single database, and graphics and multimedia files reside in one directory on the server, a cumbersome system of naming conventions was necessary to prevent files and database records from being overwritten. While creating questions with QMP’s authoring application – Question Manager – authors wanting to refer to graphics or multimedia files had to insert in a non-intuitive way the pathname of the graphics directory on the server. Moreover QMP’s server software never commits a delete transaction in the question database. This caused major problems for authors reloading assessments to the central database after having deleted one or more questions. To cope with these problems the Computing Centre of Leuven University has developed an upload application for use by the academic staff members. This application, which is described in detail in the second part of this paper, meets the constraints of a campus wide setup of QMP’s assessment software

On the Symmetries of the Edgar-Ludwig Metric

The conformal Killing equations for the most general (non-plane wave) conformally flat pure radiation field are solved to find the conformal Killing vectors. As expected fifteen independent conformal Killing vectors exist, but in general the metric admits no Killing or homothetic vectors. However for certain special cases a one-dimensional group of homotheties or motions may exist and in one very special case, overlooked by previous investigators, a two-dimensional homethety group exists. No higher dimensional groups of motions or homotheties are admitted by these metrics.Comment: Plain TeX, 7 pages, No figure

Interpreting a conformally flat pure radiation space-time

A physical interpretation is presented of the general class of conformally flat pure radiation metrics that has recently been identified by Edgar and Ludwig. It is shown that, at least in the weak field limit, successive wave surfaces can be represented as null (half) hyperplanes rolled around a two-dimensional null cone. In the impulsive limit, the solution reduces to a pp-wave whose direction of propagation depends on retarded time. In the general case, there is a coordinate singularity which corresponds to an envelope of the wave surfaces. The global structure is discussed and a possible vacuum extension through the envelope is proposed.Comment: 9 pages, Plain TeX, 2 figures. To appear in Class. Quantum Grav. Reference adde