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1.
AimThe aim of our paper was to explore expressions of life choices and life chances (aspects of agency within structures) related to power and experiences of health among early unemployed adolescent young men during the transition period to adulthood. These expressions of agency within structure were interpreted in the light of Cockerham’s Health Lifestyles Theory. Furthermore, social constructions of masculinities were addressed in our analysis.MethodsRepeated interviews with ten young men in a cohort of school leavers were analyzed with qualitative content analysis.ConclusionsQualitative research could contribute to develop the understanding of the agency within structure relationships. Future studies need to pay attention to experiences of health among young people at the margin of the labor market in various milieus – and to analyze these in relation to gender constructions and within the frame-work of agency within structure.  相似文献   
2.
Effects of eccentric exercise on the immune system in men   总被引:10,自引:0,他引:10  
The effects of eccentric exercise on changes innumbers of circulating leukocytes, cell activation, cell adhesion, andcellular memory function were investigated in 12 men, aged 22-35yr. The immunologic effects of postexercise epidermal treatment withmonochromatic, infrared light were also evaluated. Blood was drawnbefore and 6, 24, and 48 h after exercise for phenotyping and analysisof creatine kinase activity. There was an increase in leukocyte, monocyte, and neutrophil number, no change in the number of basophils, eosinophils, B cells, and T cells, and a decrease in natural killer cell number postexercise. Some markers of lymphocyte and monocyte activation remained unchanged or decreased, whereas the expression ofadhesion molecules 62L and 11b increased on monocytes. It is concludedthat eccentric exercise induced decreased activation, and increasedcell adhesion capacity, of monocytes. Altered trafficking of cellsbetween lymphoid tissue and blood, selective apoptosis, orattachment/detachment from the endothelial wall can explain theobserved phenotypic changes. Treatment with monochromatic, infraredlight did not significantly affect any of the investigated variables.Correlations between immunologic and physiological parameters indicatea role of the immune system in adaptation to physical exercise.  相似文献   
3.
The community structure of two confluent streams in southern Sweden was investigated, one stream was spring-fed and the other lake-fed. There was a downstream decrease in the number of species present in the lake outlet stream, no such change being discernible in the spring-fed stream. Taking the sampling site nearest the source of the spring-fed stream as the reference point, there was a downstream increase in dissimilarity and this increase was maintained upstream from the confluence in the lake-fed stream. Apart from generalists, all functional feeding groups showed decreased numbers from the lake outlet to the confluence in the lake-fed stream. In the spring-fed stream, densities of functional groups increased downstream, with the exception of grazers and generalists. There were indications of more predictable changes along the lake-fed stream compared to the spring-fed one, which seemed more influenced by site-specific factors.  相似文献   
4.
The enchytraeid genus Lumbricillus comprises about 80 described species of clitellate worms, which are up to a few centimetres long, and they mostly inhabit the littoral zone of non‐tropical marine and brackish waters world‐wide. The phylogeny of this genus is poorly studied, but previous work has suggested that Lumbricillus is a non‐monophyletic group. In this study, species boundaries and the phylogeny of this genus is re‐assessed using more than 300 DNA‐barcoded specimens (using COI mtDNA), part of which was also sequenced for two additional mitochondrial and four nuclear molecular markers. Statistical and coalescent based applications were used for the delimitation of a total of 24 species, of which 20 were identified as belonging to 17 described morphospecies; one morphospecies was found to be a complex of four delimited species, and another four delimited species could not be matched with any described species. Furthermore, gene trees, concatenation and multispecies coalescent based species trees were estimated using Bayesian inference. The estimated phylogenies confirm a non‐monophyletic Lumbricillus as L. semifuscus is clearly excluded from the genus. Furthermore, the placement of a monophyletic clade consisting of L. arenarius, L. dubius, and an unidentified species varies between analyses; they are either found as the sister‐group to the genus Grania or as sister‐group to the remaining Lumbricillus, where the latter relationship is supported by the multispecies coalescent, which we consider as the most reliable method.  相似文献   
5.
Stable cationic carotenoid aggregates — predominantly of the J-type — develop when the hydrochlorides of carotenoid aldoximes and ketoximes are exposed to water. The oxime hydrochlorides are obtained by simple syntheses from commercially available food color carotenoids. Bluish-purple, unstable transient compounds were observed during hydrochlorination performed at liquid nitrogen temperature.  相似文献   
6.
7.
Platelet-derived growth factor D (PDGF-D) is the most recently discovered member of the PDGF family. PDGF-D signals through PDGF receptor β, but its biological role remains largely unknown. In contrast to other members of the PDGF family of growth factors, which have been extensively investigated using different knockout approaches in mice, PDGF-D has until now not been characterized by gene inactivation in mice. Here, we present the phenotype of a constitutive Pdgfd knockout mouse model (Pdgfd-/-), carrying a LacZ reporter used to visualize Pdgfd promoter activity. Inactivation of the Pdgfd gene resulted in a mild phenotype in C57BL/6 mice, and the offspring was viable, fertile and generally in good health. We show that Pdgfd reporter gene activity was consistently localized to vascular structures in both postnatal and adult tissues. The expression was predominantly arterial, often localizing to vascular bifurcations. Endothelial cells appeared to be the dominating source for Pdgfd, but reporter gene activity was occasionally also found in subpopulations of mural cells. Tissue-specific analyses of vascular structures revealed that NG2-expressing pericytes of the cardiac vasculature were disorganized in Pdgfd-/- mice. Furthermore, Pdgfd-/- mice also had a slightly elevated blood pressure. In summary, the vascular expression pattern together with morphological changes in NG2-expressing cells, and the increase in blood pressure, support a function for PDGF-D in regulating systemic arterial blood pressure, and suggests a role in maintaining vascular homeostasis.  相似文献   
8.
Arctic and subarctic (i.e., [sub]arctic) ecosystems are predicted to be particularly susceptible to climate change. The area of tundra is expected to decrease and temperate climates will extend further north, affecting species inhabiting northern environments. Consequently, species at high latitudes should be especially susceptible to climate change, likely experiencing significant range contractions. Contrary to these expectations, our modelling of species distributions suggests that predicted climate change up to 2080 will favour most mammals presently inhabiting (sub)arctic Europe. Assuming full dispersal ability, most species will benefit from climate change, except for a few cold-climate specialists. However, most resident species will contract their ranges if they are not able to track their climatic niches, but no species is predicted to go extinct. If climate would change far beyond current predictions, however, species might disappear. The reason for the relative stability of mammalian presence might be that arctic regions have experienced large climatic shifts in the past, filtering out sensitive and range-restricted taxa. We also provide evidence that for most (sub)arctic mammals it is not climate change per se that will threaten them, but possible constraints on their dispersal ability and changes in community composition. Such impacts of future changes in species communities should receive more attention in literature.  相似文献   
9.
Oat leaf base: tissue with an efficient regeneration capacity   总被引:1,自引:1,他引:0  
Summary An efficient short term regeneration system using seedling derived oat (Avena sativa) leaf tissue has been developed. Callus derived from the leaf base showed a higher response of plant regeneration than callus initiated from mesocotyls and more mature parts of the leaves. A correlation between the nuclear DNA content of the donor material, as analysed with flow cytometry, and its ability to form callus was observed. Somatic embryogenesis was histologically recognised from callus derived from tissue close to the apical meristem. Plant regeneration media with various concentrations of auxin were tested. Callus from three different cultivars had a similar regeneration potential with an optimal regeneration frequency of 60%. About 2 months after inoculation regenerated plantlets could be moved to a greenhouse for cultivation.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - DAPI 6-diamidino-2-phenylindole - IAA indole-3-acetic acid - KT kinetin - MS Murashige and Skoog's medium - NAA naphthalene acetic acid  相似文献   
10.
Individual variation in the degree of feather wear is potentially a useful marker of individual quality or fitness, but next to nothing is known about causes and fitness consequences of feather wear in birds. We studied the effects of sex, age, year and experimental manipulation of brood size on primary feather wear in Collared Flycatchers Ficedula albicollis , and related variation in degree of feather wear to differences in fitness (viz. recruitment, survival). At the end of the breeding period, females and young birds had more worn flight feathers than males and adult birds, and the sexual difference in the degree of feather wear was particularly pronounced in one of the two study years. Experimental reduction of brood size reduced the degree of primary feather wear, whereas experimental enlargement of brood size did not lead to increased feather wear. In both sexes, there was a clear tendency for very old (>5 years old) birds to have more worn feathers than middle aged birds. The individual differences in the degree of feather wear were not correlated with individual differences in recruitment rate of young, but survival probability to the next breeding season increased with increasing degree of feather wear.  相似文献   
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