6,231 research outputs found

    On Teachers Quality Decline

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    Evidence suggests the average ability of teachers to have progressively declined in developed countries over the last decades. Many explanations have been proposed, all suggesting the idea of a lower attractiveness of teaching professions (both in monetary and non monetary terms) with respect to feasible alternative working opportunities. This should apply to women at least, because of the great expansion of job opportunities which interested female cohorts in the second half of the century. However, the long lasting problem of getting credible ability measures has often driven partial results. Here two UK population samples of individuals born in different years are considered. Individuals were exposed to ability tests at early stages of their life, so that subsequent education paths are exogenous to test scores. Transformation in percentiles allows to get comparable measures of ability, and distributions for those who undertook the teaching career are obtained in the two samples. Consistently with previous literature, using difference-in-difference, we find evidence of teachers quality decline. A gender based analysis is performed in order to address gender differences and specific questions. Data on salaries, ditributions across jobs and social mobility are finally used in order to find possible explanations. Further questions arise.teachers quality; ability measure; NCDS; BCS; difference in difference; social mobility

    Methods of analysis of local tourist systems

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    The phenomenon of tourism, due to the variables involved and their instability, is a highly complex and dynamic sector. Faced with an increasingly competitive market, characterized by political, economic and social megatrends which affect local performance, the role of the setting becomes significant. In fact, territorial properties, through tangible and intangible elements, can trigger the development process or,conversely, affect the evolution when the local context does not allow for growth conditions and management of competition. The variety of configurations, structures and phenomena within the territory make it a highly structured knowledge process, with the enhancing and upgrading of the local characteristics. However, one of the main problems is that legislation does not clarify the operational aspect of a definite boundary between Local Touristic System within the territorial context, deferring the need to identify approaches to the districts themselves. The choice of variables to investigate and the systemic reading that they should be given, determine the responsibility of creating a functional knowledge framework to the adoption of decision trajectories in line with territorial inclinations. The proposal that has inspired and supported the research presented in this paper can also be included within this context, with scientific applications and knowledge requirements needed by policy makers engaged in the drawing up and implementation of local development policiestourism; local systems; methodology of analysis; districts.

    Parallel Factorizations in Numerical Analysis

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    In this paper we review the parallel solution of sparse linear systems, usually deriving by the discretization of ODE-IVPs or ODE-BVPs. The approach is based on the concept of parallel factorization of a (block) tridiagonal matrix. This allows to obtain efficient parallel extensions of many known matrix factorizations, and to derive, as a by-product, a unifying approach to the parallel solution of ODEs.Comment: 15 pages, 5 figure

    Variable-step finite difference schemes for the solution of Sturm-Liouville problems

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    We discuss the solution of regular and singular Sturm-Liouville problems by means of High Order Finite Difference Schemes. We describe a code to define a discrete problem and its numerical solution by means of linear algebra techniques. Different test problems are proposed to emphasize the behaviour of the proposed algorithm

    Immunization against Hepatitis B Surface Antigen (HBsAg) in a Cohort of Nursing Students Two Decades after Vaccination: Surprising Feedback

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    Health-care students can be exposed to biological risks during university training. The persistence of long-term immunogenicity against hepatitis B virus (HBV) was analyzed in a cohort of nursing students two decades after primary vaccination. A total of 520 students were enrolled at the University of Palermo and were evaluated for levels of anti-HBsAg antibodies. ThestudentswereexaminedduringtheïŹrstyearoftheirDegreeCourseandwerecheckedtwoyears later. All students with anti-HBsAg <10 mIU/mL during their ïŹrst or third year were boosted within onemonth. Theproportionofstudentsthatwerevaccinatedduringadolescenceshowinganti-HBsAg ≄10 mIU/mL was higher than that observed in students who were vaccinated during infancy (69% versus31.7%;p-value<0.001). ReceivingHBVvaccinationatadolescencewassigniïŹcantlyassociated with a fourfold increased possibility of having anti-HBsAg titers≄10 mIU/mL (adj-OR = 4.21, 95% CI: 2.43–7.30). Among the students who were checked at the third year and boosted after the ïŹrst year (n = 279), those who were vaccinated during infancy showed a higher percentage of antibody titers <10 mIU/mL (20.3% versus 8.7% among vaccinated during adolescence; p < 0.01). This study conïŹrms that HBV vaccination at adolescence might determine a higher long-term persistence of anti-HBsAg titers≄10 mIU/mL and that anti-HBV booster could increase levels of anti-HBsAg over a relatively short period, especially in subjects who were vaccinated during infancy
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