118,326 research outputs found
The labour market effects of Alma Mater: Evidence from Italy
No full textWe use data from a nationally representative survey of Italian graduates to study whether Alma Mater matters for employment and earnings 3 years after graduation. We find that the attended college matters, and that there are important college-related differences, both among and within regions of the country. These differences, however, do not persist over time and are not large enough to trigger substantial mobility flows from poorly performing to better performing institutions. We also find evidence that going to a private university pays off at least in the early part of a career. Only part of this gain can be explained by the fact that private universities have lower pupil-teacher ratios than public institutions
Improving insect conservation across heterogeneous landscapes using species–habitat networks
No full textBackground: One of the biggest challenges in conservation is to manage multiple habitats for the effective conservation of multiple species, especially when the focal species are mobile and use multiple resources across heterogeneous protected areas. The application of ecological network tools and the analysis of the resulting species–habitat networks can help to describe such complex spatial associations and improve the conservation of species at the landscape scale. Methods: To exemplify the application of species–habitat networks, we present a case study on butterflies inhabiting multiple grassland types across a heterogeneous protected area in North-East Italy. We sampled adult butterflies in 44 sites, each belonging to one of the five major habitat types in the protected area, that is, disturbed grasslands, continuous grasslands, evolved grasslands, hay meadows and wet meadows. First, we applied traditional diversity analyses to explore butterfly species richness and evenness. Second, we built and analyzed both the unipartite network, linking habitat patches via shared species, and the bipartite network, linking species to individual habitat patches. Aims: (i) To describe the emerging properties (connectance, modularity, nestedness, and robustness) of the species–habitat network at the scale of the whole protected area, and (ii) to identify the key habitats patches for butterfly conservation across the protected area, that is, those supporting the highest number of species and those with unique species assemblages (e.g., hosting specialist species). Results: The species–habitat network appeared to have a weak modular structure, meaning that the main habitat types tended to host different species assemblages. However, the habitats also shared a large proportion of species that were able to visit multiple habitats and use resources across the whole study area. Even butterfly species typically considered as habitat specialists were actually observed across multiple habitat patches, suggesting that protecting them only within their focal habitat might be ineffective. Our species–habitat network approach helped identifying both central habitat patches that were able to support the highest number of species, and habitat patches that supported rare specialist species
Parental assortative mating and the intergenerational transmission of human capital
No full textWe study the contribution of parental educational assortative mating to the intergenerational transmission of educational attainment. We develop an empirical model for educational correlations within the family in which parental educational sorting can translate into intergenerational transmission jointly by both parents, or transmission can originate from each parent independently. Estimating the model using educational attainment from Danish population-based administrative data for over 400,000 families, we find that on average 75 percent of the intergenerational correlation in education is driven by the joint contribution of the parents. We also document a 38 percent decline of assortative mating in education for parents born between the early 1920s and the early 1950s. While the raw correlations also show decreases in father- and mother-specific intergenerational transmissions of educational attainment, our model shows that once we decompose all factors of intergenerational mobility, the share of intergenerational transmission accounted for by parent-specific factors increased from 7 to 27 percent; an increase compensated by a corresponding fall in joint intergenerational transmission from both parents, leaving total intergenerational persistence unchanged. The mechanisms of intergenerational transmission have changed, with an increased importance of one-to-one parent-child relationships
Fondamenti di psicopedagogia
No full textIl volume riflette ed espone i più significativi studi scientifici e le principali ricerche sperimentali di psicopedagogia, e si segnala per il risvolto pedagogico e didattico con cui vengono trattati argomenti di carattere psicologico
Student performance may not improve when universities are choosier
No full textWe use unique administrative data from a leading Italian university to estimate whether the use of admission tests and conditional progression schemes are effective strategies to select high-performing students. Previous work, which has been predominantly correlational, has focused on the effect of selectivity policies on widening university access for individuals from ethnic minorities and disadvantaged backgrounds. Our evaluation method applies a difference-indifference (DD) design, which, under the assumption that the trends of the outcome variables would be the same across all departments within the same university in the absence of treatment, identifies the causal impact of selectivity policies. The estimates indicate that selectivity schemes may not lead university students to achieve better outcomes, in terms of greater likelihoods of completing their degrees, obtaining top marks and finishing their studies within the required minimum period. The study concludes with a discussion of the main findings and their implications. © 2011 Taylor & Francis
Earnings Instability and Tenure
No full textWe study the effect of tenure on earnings instability in Italy using the reforms of temporary employment contracts which affected the average tenure of workers differentially across cohorts. We develop a model of earnings dynamics and exploit the variation of tenure and instability over time and across birth cohorts to estimate policy-relevant parameters. Our results indicate that each year of tenure on the job reduces earnings instability by 11%; the drop is faster in the first three years of the match. Workers on a temporary contract have an earnings instability up to 100% higher than workers on a permanent contract
Listeria monocytogenes survey in cubed cooked ham packaged in modified atmosphere and bioprotective effect of selected lactic acid bacteria
No full textThe aim of this work was to study the presence of Listeria monocytogenes, as well as the potential activity of two bioprotective cultures (Lyocarni BOX-74 and Lyocarni BOX-57), versus a mix of three L. monocytogenes strains that were intentionally inoculated in cooked cubed ham, packaged in Modified Atmosphere Packaging and stored at different temperatures. The bioprotective cultures limit L. monocytogenes growth in cubed cooked ham stored either at 4◦ C for 60 days and at 4◦ C for 20 days and at 8◦ C for 40 days. The inhibition at 8◦ C is particularly useful for industrial cooked meat products, considering there are often thermal abuse conditions (8◦ C) in the supermarkets. Both the starters can eliminate L. monocytogenes risk and maintain the products safe, despite the thermal abuse conditions. In addition, both culture starters grew without producing perceptible sensory variations in the samples, as demonstrated by the panel of the untrained tasters. The bioprotective LAB produced neither off-odours and off-flavours, nor white/viscous patinas, slime, discoloration or browning. Therefore, according to the obtained data, and despite the fact that cooked cubed ham did not show pH ≤ 4.4 or aw ≤ 0.92, or pH ≤ 5.0 and aw ≤ 0.94, as cited in the EC Regulation 2073/2005. It can be scientifically stated that cubes of cooked ham with the addition of bioprotective starters cultures do not constitute a favourable substrate for L. monocytogenes growth. Consequently, these products can easily fall into category 1.3 (ready-to-eat foods that are not favourable to L. monocytogenes growth, other than those for infants and for special medical purposes), in which a maximum concentration of L. monocytogenes of 100 CFU g−1 is allowed
Analysis of the Bioprotective Potential of Different Lactic Acid Bacteria Against Listeria monocytogenes in Cold-Smoked Sea Bass, a New Product Packaged Under Vacuum and Stored at 6 ± 2°C
No full textThe aim of the work was to monitor the presence of Listeria monocytogenes in cold-smoked fish products (trout, salmon, and sea bass) marketed in Italy. Cold-smoked sea bass is a new product that has not yet been commercialized and was collected from the production facility. Monitoring data have shown that cold-smoked products can be contaminated by L. monocytogenes, the presence of which has been highlighted mainly by enrichment culture (presence in 25 g). The isolated Listeria were serotyped and belonged mainly to low-virulence serotypes (1/2c), followed by serotypes 1/2a, 1/2b, and 4b. Furthermore, considering the ability of L. monocytogenes to grow in these products due to their chemical–physical characteristics (pH > 6.0, Aw > 0.97) and long shelf life at 4°C, an additional aim was to verify the activity of different bioprotective starters, including Lactilactobacillus sakei (LAK-23, Sacco srl, Via Alessandro Manzoni 29/A, 22071 Cadorago, CO, Italy), Carnobacterium spp., Lacticaseibacillus casei (SAL 106), and Lacticaseibacillus paracasei (SAL 211), in cold-smoked sea bass. All starters were bacteriocin producers. For this experiment, smoked sea bass samples were intentionally inoculated with a mixture of three different strains of L. monocytogenes and of each starter culture. After inoculation, the smoked sea bass were vacuum-packed and stored at 6 ± 2°C for 60 days, simulating the typical abuse storage temperature of markets and home refrigerators. At 0, 15, 30, 45, and 60 days, the sea bass samples were analyzed to evaluate the effectiveness of the starters against L. monocytogenes. Listeria monocytogenes growth was prevented only by the addition of the LAK-23 starter. Indeed, at the end of the shelf life, the amount of L. monocytogenes observed was similar to that in the inoculum. Consequently, the use of this starter can allow the inclusion of cold-smoked sea bass or smoked fish products in category 1.3 of Regolamento CE 2073/2005, which are products that do not support the growth of this microorganism. Finally, the activity of the LAK-23 starter did not produce an off flavor or off odor in the smoked sea bass
Workers, Firms and Life-Cycle Wage Dynamics
No full textStudies of individual wage dynamics typically ignore firm heterogeneity, whereas decompositions of earnings into worker and firm effects abstract from life-cycle considerations. We study firm effects in individual wage dynamics using administrative data on the population of Italian employers and employees. We propose a novel identification strategy for firm-related wage components exploiting the informative content of the wage covariance structure of coworkers. Wage inequality increases three-fold over the working life; firm effects are predominant while young, but sorting of workers into firms becomes increasingly important, explaining the largest share of lifetime inequality. Static models that do not allow for life-cycle dynamics underestimate the importance of sorting and overstate match and firm effects
- …
