Wolf-Rayet optically thick winds with Alfven waves

The Wolf-Rayet (WR) stars are hot luminous objects which are suffering an extreme mass loss via a continuous stellar wind. The high values of mass loss rates and high terminal velocities of the WR stellar winds constitute a challenge to the theories of radiation driven winds. Several authors incorporated magnetic forces to the line driven mechanism in order to explain these characteristics of the wind. Observations indicate that the WR stellar winds may reach, at the photosphere, velocities of the order of the terminal values, which means that an important part of the wind acceleration occurs at the optically thick region. The aim of this study is to analyze a model in which the wind in a WR star begins to be accelerated in the optically thick part of the wind. We used as initial conditions stellar parameters taken from the literature and solved the energy, mass and momentum equations. We demonstrate that the acceleration only by radiative forces is prevented by the general behavior of the opacities. Combining radiative forces plus a flux of Alfven waves, we found in the simulations a fast drop in the wind density profile which strongly reduces the extension of the optically thick region and the wind becomes optically thin too close its base. The understanding how the WR wind initiate is still an open issue. (C) 2010 COSPAR. Published by Elsevier Ltd. All rights reserved.

Feeding habits of the maned wolf, Chrysocyon brachyurus (Carnivora: Canidae), in southeast Brazil

The feeding habits of the maned wolf were studied in southeast Brazil to understand its response towards changes in the environment and in relation to its prey. By occurrence, miscellaneous fruits, small mammals and wolf`s fruit were the most consumed items. Armadillos, small mammals and wolf`s fruit ( Solanum lycocarpum) provided most of the ingested biomass. While wolf`s fruit and small mammals were mainly consumed in the dry season, other miscellaneous fruits were taken mostly in the wet season. There was selectivity in the predation on some small mammal species. The maned wolf`s diet followed patterns similar to those found in more pristine areas.

Rapport från/Report from IEA Task-14 mötet/meeting on solar heating system, Hameln Tyskland/Germany August 1992

Participation as observer at the meeting of Task 14 of IEA's Solar Heating and Cooling Projects held in Hameln, Germany has led to greater understanding of interesting developments underway in several countries. This will be of use during the development of small scale systems suitable for Swedish conditions. A summary of the work carried out by the working groups within Task 14 is given, with emphasis on the Domestic Hot Water group. Experiences of low-flow systems from several countries are related, and the conclusion is drawn that the maximum theoretical possible increase in performance of 20% has not been achieved due to poor heat exchangers and poor stratification in the storage tanks. Positive developments in connecting tubes and pumps is noted. Further participation as observer in Task 14 meetings is desired, and is looked on favourably by the members of the group. Another conclusion is that SERC should carry on with work on Swedish storage tanks, with emphasis on better stratification and heat exchangers, and possible modelling of system components. Finally a German Do-it-Vourself kit is described and judged in comparison with prefabricated models and Swedish Do-it-Yourself kits.

Distance teacher education – some experiences from Dalarna University, SwedenPaper presented at the 33rd Annual ATEE Conference Brussels, Belgium, 23rd – 27th August 2008

Distance teaching is now-a-days used in different shapes. However, it is something different from traditional campus organised education as it systematically uses Information Communication Technology (ICT) as a key element. When the distance teacher education started in Sweden many teacher educators doubted the wisdom of this. They expressed that the educational process to become a teacher would be deteriorated. For instance, they feared for high drop out rates and difficulties to examine in a proper way. The Swedish National Agency for Higher Education has recently edited a report that showed that this form of teacher education was well adapted to the labour market, but the possibilities for the teacher students to shape their education were relatively limited. However, we still know quite little about the effects of this way to educate teacher students. This paper explores the possibility of using distance teacher education.In a case study 20 students, who were the first to finish a complete a distance teacher education at Högskolan Dalarna, were asked in a questionnaire how they had apprehended their education. We also interviewed four of these students, as well as five teacher educators.One of our findings were that the distance teacher education reached new target groups, who not had been able to participate in university studies if it not had been offered in this form. Especially, this was valid for the middle-aged women, living a long distance away from a university, with social responsibilities for children or old parents. Other findings were that these students in general were target oriented and ambitious, wrote more than the campus students and developed that kind of skill better. Marratech, an ICT system for small groups, e-mail and chat were used for the communication. Marratech was considered to permit free and spontaneous communication, both of the teacher educators and the students. Initially the teacher educators were sceptical to distance teacher education, but afterwards they were surprised of how well it had worked. They declared that they had better and nearer contact with their students and more control over the students´ performance, but some parts of the teacher education were better suitable for campus education, for example, power of creating characters. Distance teacher education was considered time consuming and demanded much activity from the teacher educators as the students wanted rapid responses. This study indicates that distance teacher education works well for mature individuals with high motivation. However, it demands more time from the teacher educators, but it gives in general good results. Still, there are pedagogical challenges to overcome. Maybe we should reflect on a mix of distance teacher education and campus based teacher education, instead of separated ways of accomplishing teacher education?

A GIS SUITABILITY ANALYSIS OF WOLF HABITAT IN MAINE

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CORRIDORS FOR WOLF REINTRODUCTION TO MAINE

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A GIS Suitability Analysis of Wolf Habitat in Maine

The range of the Gray Wolf (Canis lupus), once covering most of North America, has been drastically reduced by an estimated 95% due to habitat loss and extermination by humans. The wolf was extirpated from Maine in the 1800’s. Wolf reintroductions have been suggested for Maine, but there is some debate about how much land is suitable for wolves. I developed a wolf habitat suitability analysis using ArcGIS and data from the Maine Office of GIS and the United States National Atlas. The model incorporates land cover, presence of major roads and railways, conservation land, industrial, non-industrial, and public woodlot ownership, distance from major points of population, deer population, and slope. The model results show areas of high and low wolf suitability in Maine. The model suggests that the best potential habitat for wolves in Maine is situated in the northwest of the state. Possible future reintroductions or natural colonization from other areas would have the highest likelihood of survival in these areas.