Home Literacy and Numeracy Interact and Mediate the Relationship Between Socio-Economic Status and Early Linguistic and Numeracy Skills in Preschoolers

This longitudinal study aimed at evaluating the relationships between socio-economic status (SES) and early literacy and numeracy skills, testing home literacy and home numeracy as mediators. It also investigated the interaction of home literacy and numeracy on early literacy and numeracy skills. The study involved 310 preschool children attending the second and the third year. Parents completed questionnaires on SES and home literacy and numeracy. In the first session, children were administered language measures and non-symbolic numeracy skills and, in the second wave, tasks of early literacy and symbolic numeracy skills. Structural equation models (SEMs) showed that SES was predictive of early language and literacy skills and non-symbolic numeracy skills. In addition, home literacy and home numeracy significantly mediated the relationships between SES and children’s skills. Finally, home literacy and home numeracy showed a significant negative interaction on symbolic numeracy skills. Implications for research and educational settings are discussed

LEARNING AND BUCKET BRIGADE DYNAMICS IN CLASSIFIER SYSTEMS

Classifier systems are rule-based adaptive systems whose learning capabilities emerge from processes of selection andcompetition within a population of rules (classifiers). These processes are ruled by the values of numerical variables whichmeasure the fitness of each rule. The system's adaptivity is ensured by a fitness reallocation mechanism (the bucket brigadealgorithm) and by genetic algorithms which are responsible for the internal dynamics of the system. In this paper we discussclassifier systems as dynamical systems, the main focus being on the asymptotic dynamics due to the bucket brigade,abstracting from the action of the genetics. This topic is discussed with reference to a specific task domain, in which the systemis used as a detector of statistical properties of periodic or fluctuating external environments. We also describe a majorconsequence of the genetics on the bucket brigade dynamics, namely the proliferation of individual rules into subpopulationsof equivalent classifiers; we then show that this can eventually lead to undesired stochastic behavior or to the destabilization ofcorrect solutions devised by the system

Incidenza di problematiche respiratorie e performance di crescita di bovini da ristallo ad alto rischio BRD sottoposti a trattamento anti-infettivo d’arrivo

Introduction - The bovine respiratory disease (BRD) is the main cause of morbidity, mortality and economic loss in beef cattle rearing. Stress due to transport and adaptation to the new farming conditions, and exposure to infectious agents in the markets are the main factors predisposing to this syndrome. Other to apply strategies to boost animals immunity and to quickly restore their rumen functionality, in specific high-risk conditions, an arrival anti-infective treatment (AAT) is the only way to limit BRD morbidity. Aim - The purpose of this study was to verify the impact of BRD and growth performance in groups of animals subjected to AAT with two different active compounds. Materials and methods - In the trial were included 22 newly received beef cattle groups (975 female charolaise) considered at high-risk for BRD because of subjects and transport characteristics, and management level of the fattening rearing. The groups were randomly subjected to a different AAT with gamithromycin (12 groups, 521 animals) or tulathromycin (10 groups, 454 animals). The average weight of each group was recorded at the arrival in the fattening rearing and at the end of the productive cycle to obtain the group average daily gain. During the first 30 days of rearing the animals were daily inspected and if needed, visited and specifically treated in case of pathology. Results and discussion - The overall morbidity and BRD incidence were lower (P<0.001) in the experimental group that received the AAT with gamithromycin. The difference in morbidity has not affected the growth performance of the two experimental groups. No differences between the two groups have been recorder for locomotor apparatus diseases, gastro-intestinal pathology, mortality or number of cattle that needed to be isolated in infirmary barns. Conclusions - Considering the recent regulations concerning the rational use of antibiotics, the careful choice of preventive protocol/treatment other than the active compound used in relation not only to the pathogens but also to the BRD risk level, could be considered an effective and responsible use of drugs