Home About us Contact
|
Home About us Contact | ||
|
|
||
Geographic Populations (geographic + population)
Selected AbstractsPersistent effects of a pedagogical device targeted at prevention of severe hypoglycaemia: A randomized, controlled studyACTA PAEDIATRICA, Issue 10 2005Sam Nordfeldt Abstract Aim: To study the long-term use of self-study material in type 1 diabetes patient education targeted at the prevention of severe hypoglycaemia. Methods: Randomized 1,1,1 control study in three local hospitals. We studied 332 type 1 diabetes patients from the geographic population, aged 2.6,18.9 y at entry. The intervention group received a videotape and brochure in which interviewed patients, parents and medical experts reviewed in detail practical skills for self-control and treatment, with the aim of preventing severe hypoglycaemia. There were two control groups: one received a videotape and brochure with general diabetes information and the other only traditional treatment. Primary endpoints were severe hypoglycaemia needing assistance by another person and HbA1c. Dissemination, reading/viewing level, patients' attitudes and extra contact with caregivers were also investigated. At 24 mo, 249 subjects provided data. Results: The yearly incidence of severe hypoglycaemia decreased at 24 mo from 42% to 25% (difference 17%, 95% CI 3,31, p=0.0241) in the intervention group, but not in controls. HbA1c remained unchanged. Video use during months 13,24 was higher in the intervention group than in controls (p=0.0477), ranging from 1,15 (median 2) times, among 37% of patients (months 1,12, 100%). Higher future use was anticipated for intervention material (p=0.0003). Extra caregiver contact was related to severe hypoglycaemia (p=0.0009). The cost of the material was Autumnal moth , why autumnal?ECOLOGICAL ENTOMOLOGY, Issue 6 2001Toomas Tammaru Summary 1. As for some other spring-feeding moths, adult flight of Epirrita autumnata (Lepidoptera: Geometridae) occurs in late autumn. Late-season flight is a result of a prolonged pupal period. Potential evolutionary explanations for this phenological pattern are evaluated. 2. In a laboratory rearing, there was a weak correlation between pupation date and the time of adult emergence. A substantial genetic difference in pupal period was found between two geographic populations. Adaptive evolution of eclosion time can thus be expected. 3. Metabolic costs of a prolonged pupal period were found to be moderate but still of some ecological significance. Pupal mortality is likely to form the main cost of the prolonged pupal period. 4. Mortality rates of adults, exposed in the field, showed a declining temporal trend from late summer to normal eclosion time in autumn. Lower predation pressure on adults may constitute the decisive selective advantage of late-season flight. It is suggested that ants, not birds, were the main predators responsible for the temporal trend. 5. Egg mortality was estimated to be low; it is thus unlikely that the late adult period is selected for to reduce the time during which eggs are exposed to predators. 6. In a laboratory experiment, oviposition success was maximal at the time of actual flight peak of E. autumnata, however penalties resulting from sub-optimal timing of oviposition remained limited. [source] Intraspecific structure within three caviar-producing sturgeons (Acipenser gueldenstaedtii, A. stellatus, and Huso huso) based on mitochondrial DNA analysisJOURNAL OF APPLIED ICHTHYOLOGY, Issue 6 2005P. Doukakis Summary A survey of three mitochondrial DNA regions (control region, NADH5, cytochrome b) and comprehensive sequencing of the control region (631,646 bps) was conducted to examine whether subspecies and geographic populations within three species of Eurasian sturgeons, Acipenser gueldenstaedtii, A. stellatus, and Huso huso, are genetically distinct. Neither subspecies nor populations exhibited diagnostic distinction or reciprocal monophyly in any gene region examined. For the control region, molecular variance analyses (amova) indicate that most of the variance is because of differences among haplotypes within subspecies (H. huso: 99.6%; A. stellatus: 95.0%; A. gueldenstaedtii: 81.0%) and populations (A. gueldenstaedtii: 76.1%). Significant pairwise F -values were found for all pairwise comparisons except for Sea of Azov and Caspian Sea A. gueldenstaedtii and Caspian Sea and Black Sea A. stellatus and H. huso. Only weak genetic differentiation is apparent between select subspecies and populations, reflective of biogeographic and management history. High genetic diversity within A. gueldenstaedtii suggests the possibility of additional population structure. Future research and management projects should consider these results. [source] The evolution of trade-offs: where are we?JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 2 2007D. A. ROFF Abstract Trade-offs are a core component of many evolutionary models, particularly those dealing with the evolution of life histories. In the present paper, we identify four topics of key importance for studies of the evolutionary biology of trade-offs. First, we consider the underlying concept of ,constraint'. We conclude that this term is typically used too vaguely and suggest that ,constraint' in the sense of a bias should be clearly distinguished from ,constraint' in the sense of proscribed combinations of traits or evolutionary trajectories. Secondly, we address the utility of the acquisition,allocation model (the ,Y-model'). We find that, whereas this model and its derivatives have provided new insights, a misunderstanding of the pivotal equation has led to incorrect predictions and faulty tests. Thirdly, we ask how trade-offs are expected to evolve under directional selection. A quantitative genetic model predicts that, under weak or short-term selection, the intercept will change but the slope will remain constant. Two empirical tests support this prediction but these are based on comparisons of geographic populations: more direct tests will come from artificial selection experiments. Finally, we discuss what maintains variation in trade-offs noting that at present little attention has been given to this question. We distinguish between phenotypic and genetic variation and suggest that the latter is most in need of explanation. We suggest that four factors deserving investigation are mutation-selection balance, antagonistic pleiotropy, correlational selection and spatio-temporal variation, but as in the other areas of research on trade-offs, empirical generalizations are impeded by lack of data. Although this lack is discouraging, we suggest that it provides a rich ground for further study and the integration of many disciplines, including the emerging field of genomics. [source] POPULATION GENETIC STRUCTURE OF FINLESS PORPOISES, NEOPHOCAENA PHOCAENOIDES, IN CHINESE WATERS, INFERRED FROM MITOCHONDRIAL CONTROL REGION SEQUENCESMARINE MAMMAL SCIENCE, Issue 2 2002Guang Yang Abstract Seven hundred and twenty base pairs (bp) of the mitochondrial control region from 73 finless porpoises, Neophocaena phocaenoides, in Chinese waters were sequenced. Thirteen variable sites were determined and 17 haplotypes were defined. Of these, 5 and 7 were found only in the Yellow Sea population and the South China Sea population, respectively, whereas no specific haplo-type was found in the Yangtze River population. Phylogenetic analyses using NJ and ML algorithm did not divide the haplotypes into monophyletic clades representing recognized geographic populations of finless porpoises in Chinese waters, suggesting the existence of migration and gene flow among populations. Analysis of molecular variance showed the obvious population genetic structure (,st= 0.41, P < 0.05); however, the structure was mainly between either the Yangtze River population or the Yellow Sea population and the South China Sea population. The genetic diversity (nucleotide diversity and haplotypic diversity) of the Yellow Sea population was significantly higher than those of the Yangtze River population and the South China Sea population, suggesting the relatively later divergence of the latter two populations and supporting the Yellow Sea population as the original center of Neophocaena. [source] Brief communication: Population variation in human maxillary premolar accessory ridges (MxPAR)AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2010Scott E. Burnett Abstract The purpose of this brief communication is to report the results of an analysis of maxillary premolar accessory ridges (MxPAR), a common but understudied accessory ridge that may occur both mesial and distal to the central ridge of the buccal cusp of upper premolars. We developed a new five-grade scoring plaque to better categorize MxPAR variation. Subsequently, we conducted a population analysis of MxPAR frequency in 749 dental casts of South African Indian, American Chinese, Alaskan Eskimo, Tohono O'odham (Papago), Akimel O'odham (Pima), Solomon Islander, South African Bantu, and both American and South African Whites. Northeast Asian and Asian-derived populations exhibited the highest MxPAR frequencies while Indo-European samples (South African Indians, American and South African Whites) exhibited relatively low frequencies. The Solomon Islanders and South African Bantu samples exhibited intermediate frequencies. Our analysis indicates that statistically significant differences in MxPAR frequency exist between major geographic populations. As a result, the MxPAR plaque has now been added to the Arizona State University Dental Anthropology System, an important contribution as maxillary premolar traits are underrepresented in analyses of dental morphology. Am J Phys Anthropol 2010. © 2009 Wiley-Liss, Inc. [source] Genetic Diversity of Populations of Monilinia fructicola (Fungi, Ascomycota, Helotiales) from ChinaTHE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 2 2010JIN-YAN FAN ABSTRACT. The genetic variation among 128 isolates of Monilinia fructicola (Fungi, Ascomycota, Helotiales) from China was analyzed using Inter-Simple Sequence Repeat (ISSR) markers and compared with those of samples from California, USA and New Zealand. A total of 72 reproducible DNA fragments were scored, of which 87.5% (63/72) were polymorphic. The Nei's gene diversity and Shannon's diversity indices of three Chinese regional populations were very similar to that from California. However, several differences were observed among geographic populations of M. fructicola from both within China and between China and California. The analysis of molecular variance (AMOVA) of isolates from different geographic locations suggested that most of the observed genetic variation was found within populations. Results of this study are inconsistent with the hypothesis that the Chinese populations of M. fructicola were derived from a single or few recent migrants from other countries. Instead, our results suggest that M. fructicola has been in China long before its first official recording in 2003. [source]
| | |||||||||