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Use History (use + history)
Kinds of Use History Selected AbstractsPseudomonas community structure and antagonistic potential in the rhizosphere: insights gained by combining phylogenetic and functional gene-based analysesENVIRONMENTAL MICROBIOLOGY, Issue 9 2007Rodrigo Costa Summary The Pseudomonas community structure and antagonistic potential in the rhizospheres of strawberry and oilseed rape (host plants of the fungal phytopathogen Verticillium dahliae) were assessed. The use of a new PCR-DGGE system, designed to target Pseudomonas -specific gacA gene fragments in environmental DNA, circumvented common biases of 16S rRNA gene-based DGGE analyses and proved to be a reliable tool to unravel the diversity of uncultured Pseudomonas in bulk and rhizosphere soils. Pseudomonas -specific gacA fingerprints of total-community (TC) rhizosphere DNA were surprisingly diverse, plant-specific and differed markedly from those of the corresponding bulk soils. By combining multiple culture-dependent and independent surveys, a group of Pseudomonas isolates antagonistic towards V. dahliae was shown to be genotypically conserved, to carry the phlD biosynthetic locus (involved in the biosynthesis of 2,4-diacetylphloroglucinol , 2,4-DAPG), and to correspond to a dominant and highly frequent Pseudomonas population in the rhizosphere of field-grown strawberries planted at three sites in Germany which have different land use histories. This population belongs to the Pseudomonas fluorescens phylogenetic lineage and showed closest relatedness to P. fluorescens strain F113 (97% gacA gene sequence identity in 492-bp sequences), a biocontrol agent and 2,4-DAPG producer. Partial gacA gene sequences derived from isolates, clones of the strawberry rhizosphere and DGGE bands retrieved in this study represent previously undescribed Pseudomonas gacA gene clusters as revealed by phylogenetic analysis. [source] Meta-analysis of risk for relapse to substance use after transplantation of the liver or other solid organs,LIVER TRANSPLANTATION, Issue 2 2008Mary Amanda Dew For patients receiving liver or other organ transplants for diseases associated with substance use, risk for relapse posttransplantation is a prominent clinical concern. However, there is little consensus regarding either the prevalence or risk factors for relapse to alcohol or illicit drug use in these patients. Moreover, the evidence is inconsistent as to whether patients with pretransplantation substance use histories show poorer posttransplantation medical adherence. We conducted a meta-analysis of studies published between 1983 and 2005 to estimate relapse rates, rates of nonadherence to the medical regimen, and the association of potential risk factors with these rates. The analysis included 54 studies (50 liver, 3 kidney, and 1 heart). Average alcohol relapse rates (examined only in liver studies) were 5.6 cases per 100 patients per year (PPY) for relapse to any alcohol use and 2.5 cases per 100 PPY for relapse with heavy alcohol use. Illicit drug relapse averaged 3.7 cases per 100 PPY, with a significantly lower rate in liver vs. other recipients (1.9 vs. 6.1 cases). Average rates in other areas (tobacco use, immunosuppressant and clinic appointment nonadherence) were 2 to 10 cases per 100 PPY. Risk factors could be examined only for relapse to any alcohol use. Demographics and most pretransplantation characteristics showed little correlation with relapse. Poorer social support, family alcohol history, and pretransplantation abstinence of ,6 months showed small but significant associations with relapse (r = 0.17-0.21). Future research should focus on improving the prediction of risk for substance use relapse, and on testing interventions to promote continued abstinence posttransplantation. Liver Transpl 14:159,172. 2008. © 2008 AASLD. [source] Land-use legacies in a central Appalachian forest: differential response of trees and herbs to historic agricultural practicesAPPLIED VEGETATION SCIENCE, Issue 2 2010James M. Dyer Abstract Question: Are contemporary herb and tree patterns explained by historic land use practices? If so, are observed vegetation patterns associated with life-history characteristics, soil properties, or other environmental variables? Location: Southeastern Ohio, USA. Methods: Using archival records, currently forested sites were identified with distinct land use histories: cultivated, pasture (but not plowed), and reference sites which appear to have never been cleared. Trees were recorded by size and species on twenty 20 m × 20 m plots; percent cover was estimated for each herb species in nested 10 m × 10 m plots. Environmental characteristics were noted, and soil samples analysed for nutrient availability and organic matter. Nonmetric multidimensional scaling ordination was performed separately on both tree and herb datasets to graphically characterize community composition among plots. Life-history traits were investigated to explain observed compositional differences. Results: Vegetation patterns were explained by current environmental gradients, especially by land-use history. Cultivated and pasture sites had similar tree composition, distinct from reference sites. Herb composition of pasture and reference sites was similar and distinct from cultivated sites, suggesting the ,tenacity' of some forest herbs on formerly cleared sites. Tilling removes rhizomatous species, and disfavors species with unassisted dispersal. These life-history traits were underrepresented on cultivated sites, although ant-dispersed species were not. Conclusions: Historic land-use practices accounted for as much variation in species composition as environmental gradients. Furthermore, trees and herbs responded differently to past land-use practices. Life-history traits of individual species interact with the nature of disturbance to influence community composition. [source] Oral Language Competence, Social Skills and High-risk Boys: What are Juvenile Offenders Trying to Tell us?CHILDREN & SOCIETY, Issue 1 2008Pamela C. Snow A cross-sectional study examining the oral language abilities and social skills of male juvenile offenders is described. Fifty juvenile offenders and 50 non-offending controls completed measures of language processing and production, and measures of social skill and IQ. Information about type of offending, substance use histories and learning/literacy problems was also gathered. Young offenders performed significantly worse on all language and social skill measures, but these differences could not be accounted for on the basis of IQ. Just over half of the young offenders were identified as language impaired. This subgroup was compared with non-language impaired offending peers on a range of variables. The findings have particular implications in the areas of early intervention for high-risk boys and investigative interviewing of juvenile offenders. © 2007 The Author(s). Journal compilation © 2007 National Children's Bureau. [source] Plant species richness and environmental heterogeneity in a mountain landscape: effects of variability and spatial configurationECOGRAPHY, Issue 4 2006Alexia Dufour The loss of biodiversity has become a matter of urgent concern and a better understanding of local drivers is crucial for conservation. Although environmental heterogeneity is recognized as an important determinant of biodiversity, this has rarely been tested using field data at management scale. We propose and provide evidence for the simple hypothesis that local species diversity is related to spatial environmental heterogeneity. Species partition the environment into habitats. Biodiversity is therefore expected to be influenced by two aspects of spatial heterogeneity: 1) the variability of environmental conditions, which will affect the number of types of habitat, and 2) the spatial configuration of habitats, which will affect the rates of ecological processes, such as dispersal or competition. Earlier, simulation experiments predicted that both aspects of heterogeneity will influence plant species richness at a particular site. For the first time, these predictions were tested for plant communities using field data, which we collected in a wooded pasture in the Swiss Jura mountains using a four-level hierarchical sampling design. Richness generally increased with increasing environmental variability and "roughness" (i.e. decreasing spatial aggregation). Effects occurred at all scales, but the nature of the effect changed with scale, suggesting a change in the underlying mechanisms, which will need to be taken into account if scaling up to larger landscapes. Although we found significant effects of environmental heterogeneity, other factors such as history could also be important determinants. If a relationship between environmental heterogeneity and species richness can be shown to be general, recently available high-resolution environmental data can be used to complement the assessment of patterns of local richness and improve the prediction of the effects of land use change based on mean site conditions or land use history. [source] Socio-demographic risk factors for alcohol and drug dependence: the 10-year follow-up of the national comorbidity surveyADDICTION, Issue 8 2009Joel Swendsen ABSTRACT Aims Continued progress in etiological research and prevention science requires more precise information concerning the specific stages at which socio-demographic variables are implicated most strongly in transition from initial substance use to dependence. The present study examines prospective associations between socio-demographic variables and the subsequent onset of alcohol and drug dependence using data from the National Comorbidity Survey (NCS) and the NCS Follow-up survey (NCS-2). Design The NCS was a nationally representative survey of the prevalence and correlates of DSM-III-R mental and substance disorders in the United States carried out in 1990,2002. The NCS-2 re-interviewed a probability subsample of NCS respondents a decade after the baseline survey. Baseline NCS socio-demographic characteristics and substance use history were examined as predictors of the first onset of DSM-IV alcohol and drug dependence in the NCS-2. Participants A total of 5001 NCS respondents were re-interviewed in the NCS-2 (87.6% of baseline sample). Findings Aggregate analyses demonstrated significant associations between some baseline socio-demographic variables (young age, low education, non-white ethnicity, occupational status) but not others (sex, number of children, residential area) and the subsequent onset of DSM-IV alcohol or drug dependence. However, conditional models showed that these risk factors were limited to specific stages of baseline use. Moreover, many socio-demographic variables that were not significant in the aggregate analyses were significant predictors of dependence when examined by stage of use. Conclusions The findings underscore the potential for socio-demographic risk factors to have highly specific associations with different stages of the substance use trajectory. [source] Land use history and site location are more important for grassland species richness than local soil propertiesNORDIC JOURNAL OF BOTANY, Issue 6 2009Sara A. O. Cousins Lately there has been a shift in Sweden from grazing species-rich semi-natural grasslands towards grazing ex-arable fields in the modern agricultural landscape. Grazing ex-arable fields contain a fraction of the plant species richness confined to semi-natural grasslands. Still, they have been suggested as potential target sites for re-creation of semi-natural grasslands. We asked to what extent does fine-scale variation in soil conditions, management history and site location effect local plant diversity in grazed ex-arable fields. We examined local soil conditions such as texture, pH, organic carbon, nitrogen (N) and extractable phosphate (P) and effects on plant richness in ten pairs of grazed ex-fields and neighbouring semi-natural grasslands in different rural landscapes. Each grassland pair where in the same paddock. A multivariate test showed that site location and land use history explained more of differences in species richness than local soil property variables. Plant species richness was positively associated to grazed ex-fields with low pH, low N and P levels. Sites with high plant richness in semi-natural grasslands also had more species in the adjacent grazed ex-fields, compared to sites neighbouring less species-rich semi-natural grasslands. Although both soil properties and species richness were different in grazed ex-fields compared to semi-natural grassland, the site location within a landscape, and vicinity to species-rich grasslands, can override effects of soil properties. In conclusion, if properly located, ex-arable fields may be an important habitat to maintain plant diversity at larger spatio-temporal scales and should considered as potential sites for grassland restoration. [source] Forest History as a Basis for Ecosystem Restoration,A Multidisciplinary Case Study in a South Swedish Temperate LandscapeRESTORATION ECOLOGY, Issue 2 2007Matts Lindbladh Abstract Basic knowledge of the previous forest types or ecosystem present in an area ought to be an essential part of all landscape restoration. Here, we present a detailed study of forest and land use history over the past 2,000 years, from a large estate in southernmost Sweden, which is currently undergoing a restoration program. In particular, the aim was to identify areas with long continuity of important tree species and open woodland conditions. We employed a multidisciplinary approach using paleoecological analyses (regional and local pollen, plant macrofossil, tree ring) and historical sources (taxation documents, land surveys, forest inventories). The estate has been dominated by temperate broad-leaved trees over most of the studied period. When a forest type of Tilia, Corylus, and Quercus started to decline circa 1,000 years ago, it was largely replaced by Fagus. Even though extensive planting of Picea started in mid-nineteenth century, Fagus and Quercus have remained rather common on the estate up to present time. Both species show continuity on different parts of the estate from eighteenth century up to present time, but in some stands, for the entire 2,000 years. Our suggestions for restoration do not aim for previous "natural" conditions but to maintain the spatial vegetational pattern created by the historical land use. This study gives an example of the spatial and temporal variation of the vegetation that has historically occurred within one area and emphasizes that information from one methodological technique provides only limited information about an area's vegetation history. [source] | |||||||||||||