Students’ attitudes towards science: a long term perspective

In this study the attitudes of four pupils, two boys and two girls, towards science are followed over the course of six years. Data were obtained in two ways. First, and principally, by annual interviews undertaken in the pupils' homes throughout their science education from the ages of 11 to 16 years, and at the age of 17, one year after the ending of their compulsory schooling; secondly, by means of observations made during their science lessons in an English state (non-fee-paying) school from 1994 to 1999. Each pupil's attitudes towards science and their experiences of their school science education are described by means of quotations and episodic biographical vignettes. These allow us to track the ways in which the pupils' attitudes about science developed over the course of the study. The findings help to shed light on the reasons why many pupils lose interest in science during the course of their secondary science education

Mortality, Recruitment and Change of Desert Tree Populations in a Hyper-Arid Environment

BACKGROUND: Long-term vegetation changes in hyper-arid areas have long been neglected. Mortality, recruitment and change in populations of the ecologically and culturally important and drought persistent Acacia tortilis and Balanites aegyptiaca are therefore estimated in the Eastern Desert of Egypt, and are related to the primary agents of change, water conditions and human intervention. METHODOLOGY: A change analysis using high-resolution Corona images (1965) in combination with field data (2003) is the basis for recruitment, mortality and change estimates. For assessing the influence of water conditions on patterns in recruitment and survival, different types of generalized linear models are tested. CONCLUSIONS: The overall trend in population size in that part of the Eastern Desert studied here is negative. At some sites this negative trend is alarming, because the reduction in mature trees is substantial (>50%) at the same time as recruitment is nearly absent. At a few sites there is a positive trend and better recruitment. Frequent observations of sprouting in saplings indicate that this is an important mechanism to increase their persistence. It is the establishment itself that seems to be the main challenge in the recruitment process. There are indications that hydrological variables and surface water in particular can explain some of the observed pattern in mortality, but our results indicate that direct human intervention, i.e., charcoal production, is the main cause of tree mortality in the Eastern Desert

A dynamic simulation model of land-use, population, and rural livelihoods in the central Rift Valley of Ethiopia

The dynamic interactions between society and land resources have to be taken into account when planning and managing natural resources. A computer model, using STELLA software, was developed through active participation of purposively selected farm households from different wealth groups, age groups and gender within a rural community and some members of Kebelle council. The aim of the modeling was to study the perceived changes in land-use, population and livelihoods over the next 30 years and to improve our understanding of the interactions among them. The modeling output is characterized by rapid population growth, declining farm size and household incomes, deteriorating woody vegetation cover and worsening land degradation if current conditions remain. However, through integrated intervention strategies (including forest increase, micro-finance, family planning, health and education) the woody vegetation cover is likely to increase in the landscape, population growth is likely to slow down and households’ income is likely to improve. A validation assessment of the simulation model based on historical data on land-use and population from 1973 to 2006 showed that the model is relatively robust. We conclude that as a supporting tool, the simulation model can contribute to the decision making process

Yngre elevers lärande om naturen En studie av kommunikation om modeller i institutionella kontexter

Abstract The aim of the study is to draw attention to and examine how young students (approximately 5-13 years) are involved in communication about nature, what approaches to nature are mediated in the social practices of preschool, school, and a science center, and how functional these approaches may be as providing learners with tools for making sense in other situations in everyday life and society. Empirical investigations were carried out by observations, tape recordings and video recordings of interaction in different educational contexts and presented in three studies. The first study is about a group of preschool children (5 years old) and their teacher visiting an exhibition about the water flow at a science center and the teacher communicating with the children about their visit during circle time at the preschool. The second study is about conversations about the water cycle between teachers and young students (8-10 years old) at a primary school, with a prop in the form of a photograph taken in a real rainforest. The third study is about students (12-13 years old) working in pairs in a computer-simulated micro world of ecological processes on an African savanna. Taking a sociocultural perspective, the results indicate that in all the studied contexts, the conversations between the students and teachers were characterized by being indistinct, i.e. not being conducted within a distinct discourse. The students had difficulties following the teachers’ communication strategies. It seemed to be important for the teachers that the students themselves understood what the conversation was about and to arrive at the right answer. Students’ possibility to express their knowledge is closely dependent on the adults’ strategies. The most successful strategy for students is to follow the teacher’s way of speaking. This leads to the fact that some students succeed to talk in such a way that is expected by the teacher in the conversation. When the teacher is absent the students make sense by referring to their previous experience. Without support by the teacher the students thus thematize nature on their own terms. In the investigated activities the models are handled as if being self-illustrative. Models, as such, and how they are related to what they refer to was never explained by the teachers in the studied activities

An observation-based estimate of the strength of rainfall-vegetation interactions in the Sahel

Over the course of the twentieth century the African Sahel experienced large variations in annual precipitation; including the wet period during the 1950s and 1960s and the long-term drought during the 1970s and 1980s. Feedbacks between the land surface and atmosphere can affect rainfall variability at monthly, annual and decadal time scales. However, the strength of the coupling between the land surface and precipitation is still highly uncertain, with climate-model derived estimates differing by an order of magnitude. Here a statistical model of vegetation greenness is used to estimate the vegetation-rainfall coupling strength in the Sahel, based on monthly satellite-derived vegetation index and meteorological data. Evidence is found for a positive feedback between vegetation and rainfall at the monthly time scale, and for a vegetation memory operating at the annual time scale. These vegetation-rainfall interactions increase the interannual variation in Sahelian precipitation; accounting for as much as 30% of the variability in annual precipitation in some hot spot regions between 15° and 20°N