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Search Results: 1 - 10 of 1055 matches for " Mikael ?kesson "
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Estimating Heritabilities and Genetic Correlations: Comparing the ‘Animal Model’ with Parent-Offspring Regression Using Data from a Natural Population
Mikaelkesson, Staffan Bensch, Dennis Hasselquist, Maja Tarka, Bengt Hansson
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0001739
Abstract: Quantitative genetic parameters are nowadays more frequently estimated with restricted maximum likelihood using the ‘animal model’ than with traditional methods such as parent-offspring regressions. These methods have however rarely been evaluated using equivalent data sets. We compare heritabilities and genetic correlations from animal model and parent-offspring analyses, respectively, using data on eight morphological traits in the great reed warbler (Acrocephalus arundinaceus). Animal models were run using either mean trait values or individual repeated measurements to be able to separate between effects of including more extended pedigree information and effects of replicated sampling from the same individuals. We show that the inclusion of more pedigree information by the use of mean traits animal models had limited effect on the standard error and magnitude of heritabilities. In contrast, the use of repeated measures animal model generally had a positive effect on the sampling accuracy and resulted in lower heritabilities; the latter due to lower additive variance and higher phenotypic variance. For most trait combinations, both animal model methods gave genetic correlations that were lower than the parent-offspring estimates, whereas the standard errors were lower only for the mean traits animal model. We conclude that differences in heritabilities between the animal model and parent-offspring regressions were mostly due to the inclusion of individual replicates to the animal model rather than the inclusion of more extended pedigree information. Genetic correlations were, on the other hand, primarily affected by the inclusion of more pedigree information. This study is to our knowledge the most comprehensive empirical evaluation of the performance of the animal model in relation to parent-offspring regressions in a wild population. Our conclusions should be valuable for reconciliation of data obtained in earlier studies as well as for future meta-analyses utilizing estimates from both traditional methods and the animal model.
Individual Identification and Genetic Variation of Lions (Panthera leo) from Two Protected Areas in Nigeria
Talatu Tende, Bengt Hansson, Ulf Ottosson, Mikaelkesson, Staffan Bensch
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0084288
Abstract: This survey was conducted in two protected areas in Nigeria to genetically identify individual lions and to determine the genetic variation within and between the populations. We used faecal sample DNA, a non-invasive alternative to the risky and laborious task of taking samples directly from the animals, often preceded by catching and immobilization. Data collection in Yankari Game Reserve (YGR) spanned through a period of five years (2008 –2012), whereas data in Kainji Lake National Park (KLNP) was gathered for a period of three years (2009, 2010 and 2012). We identified a minimum of eight individuals (2 males, 3 females, 3 unknown) from YGR and a minimum of ten individuals (7 males, 3 females) from KLNP. The two populations were found to be genetically distinct as shown by the relatively high fixation index (FST = 0.17) with each population exhibiting signs of inbreeding (YGR FIS = 0.49, KLNP FIS = 0.38). The genetic differentiation between the Yankari and Kainji lions is assumed to result from large spatial geographic distance and physical barriers reducing gene flow between these two remaining wild lion populations in Nigeria. To mitigate the probable inbreeding depression in the lion populations within Nigeria it might be important to transfer lions between parks or reserves or to reintroduce lions from the zoos back to the wild.
Annual Cycle and Migration Strategies of a Trans-Saharan Migratory Songbird: A Geolocator Study in the Great Reed Warbler
Hilger W. Lemke, Maja Tarka, Raymond H. G. Klaassen, Mikaelkesson, Staffan Bensch, Dennis Hasselquist, Bengt Hansson
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0079209
Abstract: Recent technological advancements now allow us to obtain geographical position data for a wide range of animal movements. Here we used light-level geolocators to study the annual migration cycle in great reed warblers (Acrocephalus arundinaceus), a passerine bird breeding in Eurasia and wintering in sub-Saharan Africa. We were specifically interested in seasonal strategies in routes and schedules of migration. We found that the great reed warblers (all males, no females were included) migrated from the Swedish breeding site in early August. After spending up to three weeks at scattered stopover sites in central to south-eastern Europe, they resumed migration and crossed the Mediterranean Sea and Sahara Desert without lengthy stopovers. They then spread out over a large overwintering area and each bird utilised two (or even three) main wintering sites that were spatially separated by a distinct mid-winter movement. Spring migration initiation date differed widely between individuals (1-27 April). Several males took a more westerly route over the Sahara in spring than in autumn, and in general there were fewer long-distance travels and more frequent shorter stopovers, including one in northern Africa, in spring. The shorter stopovers made spring migration on average faster than autumn migration. There was a strong correlation between the spring departure dates from wintering sites and the arrival dates at the breeding ground. All males had a high migration speed in spring despite large variation in departure dates, indicating a time-minimization strategy to achieve an early arrival at the breeding site; the latter being decisive for high reproductive success in great reed warblers. Our results have important implications for the understanding of long-distance migrants’ ability to predict conditions at distant breeding sites and adapt to rapid environmental change.
New approaches to pharmacological treatment of osteoporosis
kesson,Kristina;
Bulletin of the World Health Organization , 2003, DOI: 10.1590/S0042-96862003000900008
Abstract: osteoporosis has been recognized as a major public health problem for less than two decades. the increasing incidence of fragility fractures, such as vertebral, hip, and wrist fractures, first became apparent from epidemiological studies in the early and mid-1980s, when effective treatment was virtually unavailable. pharmacological therapies that effectively reduce the number of fractures by improving bone mass are now available widely in countries around the world. most current agents inhibit bone loss by reducing bone resorption, but emerging therapies may increase bone mass by directly promoting bone formation - as is the case with parathyroid hormone. current treatment alternatives include bisphosphonates, calcitonin, and selective estrogen receptor modulators, but sufficient calcium and vitamin d are a prerequisite. the availability of evidence-based data that show reductions in the incidence of fractures of 30-50% during treatment has been a major step forward in the pharmacological prevention of fractures. with all agents, fracture reduction is most pronounced for vertebral fracture in high-risk individuals; alendronate and risedronate also may protect against hip fracture in the elderly. new approaches to pharmacological treatment will include further development of existing drugs, especially with regard to tolerance and frequency of dosing. new avenues for targeting the condition will emerge as our knowledge of the regulatory mechanisms of bone remodelling increases, although issues of tissue specificity may be difficult to solve. in the long term, information gained through knowledge of bone genetics may be used to adapt pharmacological treatments more precisely to each individual.
Making Migrants Responsible for Development: Cape Verdean Returnees and Northern Migration Policies Wenn Migranten für Entwicklung verantwortlich gemacht werden: Rückkehrer nach Kap Verde und vom Norden“ gepr gte Migrationspolitik
Lisa ?kesson
Africa Spectrum , 2011,
Abstract: In recent years, there has been a surge of “Northern” policy documents concerned with increasing the positive effects of international migration in countries of origin. This article contrasts some basic assumptions in policies on migration, return and development with an anthropological study of Cape Verdean returnees, and it reveals some important disparities between the returnees’ experiences and the ideas underpinning policy documents. The article analyses the role returnees’ savings and skills play in local change in Cape Verde, and in particular it looks into entrepreneurial activities. This is related to a discussion of the conditions that must be fulfilled in order to make it possible for return migrants to contribute to positive social change. In conclusion, the article shows that structural conditions have a fundamental impact on individual migrants’ abilities to support development, a perspective often left out of contemporary policies. In jüngster Zeit entstand eine Flut politischer Dokumente im “Norden”, die sich mit den positiven Effekten internationaler Migration in den Ursprungsl ndern der Migranten besch ftigen. Der vorliegende Beitrag kontrastiert einige grundlegende Annahmen im Bereich der Migrations-, Rückkehrer- und Entwicklungspolitik mit den Ergebnissen einer anthropologischen Studie über Rückkehrer nach Kap Verde und deckt einige gravierende Differenzen zwischen diesen Grundannahmen und den Erfahrungen der Rückkehrer auf. Die Autorin analysiert, welche Bedeutung die Ersparnisse und die Qualifikationen der Rückkehrer für den lokalen gesellschaftlichen Wandel haben und ist dabei insbesondere an unternehmerischen Aktivit ten interessiert. Darauf aufbauend diskutiert sie, unter welchen Bedingungen zurückkehrende Migranten positiv zum sozialen Wandel beitragen k nnen. Sie kommt zu dem Schluss, dass die M glichkeiten für einzelne Rückkehrer, die Entwicklung ihres Heimatlandes positiv zu beeinflussen, stark von strukturellen Gegebenheiten abh ngen – eine Tatsache, die bei politischen Planungen vielfach unberücksichtigt bleibt.
Cape Verdean Notions of Migrant Remittances
Lisa ?kesson
Cadernos de Estudos Africanos , 2011, DOI: 10.4000/cea.168
Abstract: The transfer of money from migrants to their non-migrant relatives is a key, symbol of the quality and meaning of transnational kinship relations. This article analyses how people in Cape Verde view migrant family members’ economic obligations and it examines the concomitant moral discourse. Through a detailed ethnographic study the article explores how gender and kinship positions interplay with the moral obligation to send remittances, and it also inquires into the differences between rural and urban people’s attitudes towards monetary gifts. Moreover, the importance of the receiver’s status in the local society is discussed and the role of the personal relation between the sender and the receiver. Thus the analysis goes beyond an instrumental and rationalistic approach to remittances, which is common in much research, and explores the significance of this money for emotions and social relations. Para os seus parentes n o emigrantes as remessas dos emigrantes s o um símbolo chave da qualidade e do significado das rela es de parentesco transnacionais. Este artigo analisa como as pessoas em Cabo Verde encaram as obriga es económicas dos emigrantes membros de família e examina o discurso moral concomitante. Através de um estudo etnográfico detalhado o artigo explora como posi es de género e parentesco interagem com a obriga o moral de enviar remessas e também investiga as diferen as entre as atitudes das pessoas rurais e urbanas relativamente às ofertas monetárias. Além disso, discute-se a importancia do estatuto do receptor na sociedade local e o papel da rela o pessoal entre remetente e receptor. Assim, a análise vai além de uma abordagem instrumental e racionalista das remessas, o que é habitual em muitas pesquisas, explorando o significado deste dinheiro em termos de emo es e rela es sociais.
New approaches to pharmacological treatment of osteoporosis
kesson Kristina
Bulletin of the World Health Organization , 2003,
Abstract: Osteoporosis has been recognized as a major public health problem for less than two decades. The increasing incidence of fragility fractures, such as vertebral, hip, and wrist fractures, first became apparent from epidemiological studies in the early and mid-1980s, when effective treatment was virtually unavailable. Pharmacological therapies that effectively reduce the number of fractures by improving bone mass are now available widely in countries around the world. Most current agents inhibit bone loss by reducing bone resorption, but emerging therapies may increase bone mass by directly promoting bone formation - as is the case with parathyroid hormone. Current treatment alternatives include bisphosphonates, calcitonin, and selective estrogen receptor modulators, but sufficient calcium and vitamin D are a prerequisite. The availability of evidence-based data that show reductions in the incidence of fractures of 30-50% during treatment has been a major step forward in the pharmacological prevention of fractures. With all agents, fracture reduction is most pronounced for vertebral fracture in high-risk individuals; alendronate and risedronate also may protect against hip fracture in the elderly. New approaches to pharmacological treatment will include further development of existing drugs, especially with regard to tolerance and frequency of dosing. New avenues for targeting the condition will emerge as our knowledge of the regulatory mechanisms of bone remodelling increases, although issues of tissue specificity may be difficult to solve. In the long term, information gained through knowledge of bone genetics may be used to adapt pharmacological treatments more precisely to each individual.
Selection for Heterozygosity Gives Hope to a Wild Population of Inbred Wolves
Staffan Bensch, Henrik Andrén, Bengt Hansson, Hans Chr. Pedersen, H?kan Sand, Douglas Sejberg, Petter Wabakken, Mikaelkesson, Olof Liberg
PLOS ONE , 2006, DOI: 10.1371/journal.pone.0000072
Abstract: Recent analyses have questioned the usefulness of heterozygosity estimates as measures of the inbreeding coefficient (f), a finding that may have dramatic consequences for the management of endangered populations. We confirm that f and heterozygosity is poorly correlated in a wild and highly inbred wolf population. Yet, our data show that for each level of f, it was the most heterozygous wolves that established themselves as breeders, a selection process that seems to have decelerated the loss of heterozygosity in the population despite a steady increase of f. The markers contributing to the positive relationship between heterozygosity and breeding success were found to be located on different chromosomes, but there was a substantial amount of linkage disequilibrium in the population, indicating that the markers are reflecting heterozygosity over relatively wide genomic regions. Following our results we recommend that management programs of endangered populations include estimates of both f and heterozygosity, as they may contribute with complementary information about population viability.
Generic Substitution Effects on Firm Level Market Shares in the Finnish Beta Blocker Market 1997Q1-2007Q4  [PDF]
Mikael Linden
Modern Economy (ME) , 2013, DOI: 10.4236/me.2013.412092
Abstract:

The firm level market structure of the Finnish beta blocker market in the period from 1997Q1 to 2007Q4 is analyzed with data analysis and with panel data regression methods. Four different market concentration measures are used. Although drug prices have decreased in response to the competition-enhancing generic substitution system which started on the 1st of March 2003, the firms’ observed market shares in the market have not decreased uniformly in the all market dimensions. At the drug substitution group level, policy change has led to more equal group share distributions both for the nominal sales shares and quantity sales shares compared to the pre-policy period. At the whole market level, nominal firm sales shares of the largest firms have increased during the policy era but quantity sales shares have declined. The results imply that the dominant firms’ nominal sale shares are augmented with firm-specific drug price setting power. The results challenge the European Union (EU) drug policy targeted to increase competition in the drug markets.

 

Unschooling, Then and Now
Kellie ROLSTAD,Kathleen KESSON
Journal of Unschooling and Alternative Learning , 2013,
Abstract: While the accountability and standardization movement continues to narrow curriculum in the US, unschooling families are redefining learning and recreating community in an atmosphere of love and trust. As professors of education and unschooling mothers, Rolstad and Kesson compare their unschooling experiences in two different eras, one in the early days of unschooling (1980s), and the other in the first decade of the 21st century. Kathleen Kesson was an unschooling pioneer when her children were unschooled in the early 1980s, and her children are now adults. She describes what it was like to unschool then, to do what she terms ‘old school unschooling.’ Only a generation later, Kellie Rolstad began unschooling her three children, in a world transformed by the Internet and ease of access to both information and social networking, key components of unschooling today. Rolstad describes how her unschooling children connected play in real and virtual worlds, exploring ideas differently in many aspects from how Kesson’s children played and explored, and yet fundamentally and remarkably the same. In this article, Rolstad and Kesson share their experiences of trusting children, of giving them the space and the resources to learn and grow in the ways that are best for them, comparing along the way what it was like to unschool then and what it is like to unschool now, in this era when our society has come to distrust children more than ever.
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