Build your Responsive Open Learning Environment

The European research project ROLE (Responsive Open Learning Environments) is aiming at empowering learners for self-regulated learning within a personalised learning environment. Towards this goal, ROLE has developed a number of learning technologies, addressing a variety of learning requirements. The purpose of this roundtable is to discuss the applications of these technologies in different learning contexts, as well as the challenges associated with enabling and supporting self-regulated learning

The first total synthesis of N1999-A2: absolute stereochemistry and stereochemical implications into DNA cleavage

Enediyne antitumor antibiotics have attracted immense attention among chemists and biologists alike because of their unique chemical structures, potent antitumor activities, and fascinating biological modes of action. As a novel addition to this family, the nonprotein and extremely strained nine-membered enediyne antibiotic N1999-A2 strongly inhibits the growth of various tumor cell lines and bacteria, and cleaves DNA in a base-specific manner. The attractive features of this molecule lie not only within the chemical structure being analogous to the neocarzinostatin chromophore, itself a potent anticancer agent, but also in that it can invoke remarkably strong biological activities even without a stabilizing apoprotein carrier and a glycoside functionality that can accelerate the rate of DNA cleavage. In this regard, N1999-A2 serves as a leading enediyne-based antitumor agent with minimal functionality that is able to act on DNA selectively. We therefore focused on this unique, unstable, and stereochemically unknown compound and undertook the formidable challenge of devising an efficient strategy that would be flexible enough to ultimately construct a series of related highly strained systems

The cost of soil replacement : a Maltese case study

Soil erosion only enters national accounting systems when soil loss is reflected in lost agricultural productivity, or becomes manifest with costs sustained by damage through flooding, siltation of dams, landslides, and other associated phenomena. On islands that are prone to desertification, however, soil loss needs to be better accounted since the costs of soil replacement and rehabilitation are often prohibitively expensive. Circumscribed agricultural space provides the necessary incentive for investment in soil conservation measures and, in certain cases, a long history of such measures results in a wealth of soil retention structures. Soil conservation has been practised in the densely populated Maltese islands for several hundred years. Slope terracing and armouring of the terrace face with retaining dry stonewalls represents a rich resource which has not yet been quantified. Yet the cost of maintaining such soil conservation structures is becoming increasingly prohibitive despite the downstream costs of their eventual failure. Legislation has been enacted aimed at preserving rubble walls since these are now also regarded as a unique landscape feature but well-targeted economic incentives and support infrastructures are crucial in this regard. In fact, the Maltese Government has, over the past few years, promoted rubble wall repairs by creating groups of skilled workers trained in the craft of rubble wall building. Malta's joining the European Union in May 2004 also means that EU funds would be utilised in this regard but this needs careful management. Despite such state initiatives, alternative non-state subsidies need to be identified and this demands the identification of net beneficiaries of soil conservation. The most easily identifiable stakeholders are farmers but the tourist sector and water management authorities should also be enlisted within soil conservation management. Other stakeholders include those sectors that are adversely affected by soil erosion. In this case, insurance companies and road maintenance agencies should also be involved in soil management initiatives.peer-reviewe

The role of biomechanics in the assessment of carotid atherosclerosis severity: a numerical approach

Numerical fluid biomechanics has been proved to be an efficient tool for understanding vascular diseases including atherosclerosis. There are many evidences that atherosclerosis plaque formation and rupture are associated with blood flow behavior. In fact, zones of low wall shear stress are vivid areas of proliferation of atherosclerosis, and in particular, in the carotid artery. In this paper a model is presented for investigating how the presence of the plaque influences the distribution of the wall shear stress. In complement to a first approach with rigid walls, an FSI model is developed as well to simulate the coupling between the blood flow and the carotid artery deformation. The results show that the presence of the plaque causes an attenuation of the WSS in the after-plaque region as well as the emergence of recirculation areas

The Changing Role of Family Income and Ability in Determining Educational Achievement

This paper uses data from the 1979 and 1997 National Longitudinal Survey of Youth cohorts (NLSY79 and NLSY97) to estimate changes in the effects of ability and family income on educational attainment for youth in their late teens during the early 1980s and early 2000s. Cognitive ability plays an important role in determining educational outcomes for both NLSY cohorts, while family income plays little role in determining high school completion in either cohort. Most interestingly, we document a dramatic increase in the effects of family income on college attendance (particularly among the least able) from the NLSY79 to the NLSY97. Family income has also become a much more important determinant of college `quality' and hours/weeks worked during the academic year (the latter among the most able) in the NLSY97. Family income has little effect on college delay in either sample. To interpret our empirical findings on college attendance, we develop an educational choice model that incorporates both borrowing constraints and a `consumption' value of schooling - two of the most commonly invoked explanations for a positive family income-schooling relationship. Without borrowing constraints, the model cannot explain the rising effects of family income on college attendance in response to the sharply rising costs and returns to college experienced from the early 1980s to early 2000s: the incentives created by a `consumption' value of schooling imply that income should have become less important over time (or even negatively related to attendance). Instead, the data are more broadly consistent with the hypothesis that more youth are borrowing constrained today than were in the early 1980s.