Els models, organitzadors del currícul en biologia

Es presenta una proposta d'organització del currículum de biologia basada en determinats models teòrics. Hi justifiquem la seva idoneïtat i validesa i presentem alguns dels resultats de la seva aplicació a l'aula

Características de los ejercicios de prácticas de laboratorio incluidos en los libros de textos de Ciencias utilizados en Cataluña

The laboratory exercices in science textbooks used in grades 9 to 12 in Catalonian schools were content analyzed by three instruments: The Inquiry Leve1 Index (ILI), the Laboratory Assessment Inventory (LAI) and the Laboratory Dimenssions Inventory (LDI). The analysis was carried out by 24 teachers under the guidance of two science educators as an assignment in an in-service course on teaching and evaluation in the laboratory. It was found that the number of laboratory exercises offered in Catalonian science texbooks is rather small compared with texbooks in countries such as the U. K. and U.S.A. Most of the exercises are of low inquiry level featuring manipulation but missing high other inquiry skills such as formulating questions and hypotheses, designing experiments, etc. The relationship between practical work and theory is hardly indicated and the potential of the laboratory as a means to enhancing concept learning andlor developing social skills are hardly being considered. There is an urgent need to reform laboratory work in Catalonian schools

Do interrelated financial markets help in forecasting stock returns?

The interest in studying the interrelationships among financia! markets is c!ear, specially for banks and financial institutions. Nevertheless there are not conclusive studies on this respect. In this paper we analyze the predictive power of the obvious random walk model for stock prices when compared with other univariate and multivariate alternatives that exploit the presence of common stochastic trends in the data. We address several issues: First, can we find one (or more) common growth factors that help us in improving the forecast accuracy of the stock price indexes? And second, within the family of unobserved components models, is there any one particularly specification for the trend well suited for explaining and forecasting financial stock market data

Reliability and performance of UEGO, a clustering-based global optimizer

Den nya tullagen Union Customs Code (UCC) med målet elektroniskt tullhantering inom unionen kommer att börja tillämpas 1 maj 2016. Tullkodex för unionen innebär elektroniskt tullhantering såväl mellan näringslivet och Tullverket som mellan medlemsstaternas tulladministrationer. Syftet med lagen är att förenkla uppgiftslämning och tullhantering för företag vilket kräver omfattande uppgradering av IT-lösningar för både näringslivet och Tullverket. Kvalitet på de uppgifter som överförs till Tullverkets tull-system (TDS) antas ha större betydelse än tidigare då det genom UCC läggs en större vikt på spårbarhet.Organisationer bör därför optimera kvaliteten på de uppgifter som i samband med deklarationer lämnas till Tullverket. Detta för att undvika eventuella problem i framtiden. Optimal datakvalitet erhålls genom effektiva administrativa processer. Denna uppsats har därför genom en fallstudie studerat faktorer som förhindrar ett effektivt administrativt arbete. Resultatet visar att affärssystemets undermåliga funktionalitet, datakvalitetens opålitlighet, utebliven intern kommunikation samt avsaknad av standardiserade arbetsrutiner påverkar effektiviteten på de administrativa processerna negativt.The new customs regulation, Union Customs Code (UCC), with the goal of electronic customs handling within the European Union will apply 1 May 2016. The Union Customs Code means electronic customs handling both between business and customs Administration and between member states' customs administrations. The law aims to simplify disclosure and customs management for businesses, which requires an extensive upgrade of IT solutions for both business and customs administrations. Quality of the data transferred to Customs' Tariff System (TDS) is assumed will havegreater importance than today as the UCC places a greater emphasis on traceability. Organisations should therefore optimize the quality of the data associated with declarations submitted to Customs. It is to avoid any future problems. Optimal data quality is achieved through efficient administrative processes. This paper has therefore through a case study, studied factors that prevent efficient administrative processes. The results show that the business system's substandard functionality, data quality's unreliability, loss of internal communication and a lack of standard in operating procedures are affecting the efficiency of the administrative processes negatively

Study of the increase in bending stiffness on timber beams reinforced with composite materials

It is common to find structures that need to be reinforced due to deterioration or because the function of the building changes. The economic cost involved in these forms of interventions is considerable. Therefore, it is interesting to progress in the existing strengthening techniques and the study of new reinforcement systems. This paper analyses the behaviour of timber beams reinforced with carbon and basalt fiber composite materials. The main objective of this study is to test the stiffness increase produced by the carbon and basalt FRP on reinforced beams. The results show the stiffness increase produced by the different types of reinforcement

Reproductive and nutritional management on ovarian response and embryo quality on rabbit does

Rabbit does in modern rabbitries are under intensive reproductive rhythms. Females are high milk producers with high energetic expenses due to the extensive overlap between lactation and gestation. This situation leads to a negative energy balance with a mobilization of body fat especially in primiparous rabbit does. Poor body condition and poor health status severely affect the reproductive features (fertility rate and lifespan of the doe as well as ovarian physiology). This paper reviews some reproductive and nutritional approaches used in the last years to improve the reproductive performance of rabbit females, mainly focusing on the influence on ovarian response and embryo quality and with emphasis on epigenetic modifications in pre-implantation embryos and offspring consequences