291 research outputs found

    Social Support and Access to Healthcare as Predictors of Heart Disease Among Young Adults

    Get PDF
    Patients with heart disease must overcome a complex set of behavioral and attitudinal obstacles if they wish to have a health-related quality of life. The difficulty and frustration of this illness can be mitigated by social support and improving contextual circumstances, which has been demonstrated in previous research. A contextual variable that is likely to predict heart disease in young adults is access to healthcare. The purpose of this study was to examine whether social support and access to healthcare predicted if a young adult has heart disease

    In situ grazing resistance of Vibrio cholerae in the marine environment

    Full text link
    Previous laboratory experiments revealed that Vibrio cholerae A1552 biofilms secrete an antiprotozoal factor that prevents Rhynchomonas nasuta from growing and thus prevents grazing losses. The antiprotozoal factor is regulated by the quorum-sensing response regulator, HapR. Here, we investigate whether the antiprotozoal activity is ecologically relevant. Experiments were conducted in the field as well as under field-like conditions in the laboratory to assess the grazing resistance of V. cholerae A1552 and N16961 (natural frameshift mutation in hapR) biofilms to R. nasuta and Cafeteria roenbergensis. In laboratory experiments exposing the predators to V. cholerae grown in seawater containing high and low glucose concentrations, we determined that V. cholerae biofilms showed increased resistance towards grazing by both predators as glucose levels decreased. The relative resistance of the V. cholerae strains to the grazers under semi-field conditions was similar to that observed in situ. Therefore, the antipredator defense is environmentally relevant and not lost when biofilms are grown in an open system in the marine environment. The hapR mutant still exhibited some resistance to both predators and this suggests that V. cholerae may coordinate antipredator defenses by a combination of density-dependent regulation and environmental sensing to protect itself from predators in its natural habitat. © 2011 Federation of European Microbiological Societies

    Frequency of use metrics for American English person descriptors: Extensions of Roivainen's internet search methodology

    Get PDF
    21 pagesPersonality traits are often measured using person-descriptive terms, but data are limited regarding the frequency of usage for these terms in everyday language. This project reports on the relative frequency of usage for a large pool of American English terms (N = 18,240) using count estimates from search engine results and in books cataloged by Google. These estimates are based on the ngrams formed when each descriptor is combined with a common person-related noun (person, woman, man, girl, boy). Results are reported for each noun form and a frequency index in an online database that can be sorted, searched, and downloaded. We report on associations among the different noun forms and data types, and propose recommendations for the use of these data in conjunction with other resources. In particular, we encourage collaborative approaches among research teams using large language models in psycholexical research related to personality structure

    Data collection challenges in community settings: Insights from two field studies of patients with chronic disease

    Get PDF
    Purpose Collecting information about health and disease directly from patients can be fruitfully accomplished using contextual approaches, ones that combine more and less structured methods in home and community settings. This paper's purpose is to describe and illustrate a framework of the challenges of contextual data collection. Methods A framework is presented based on prior work in community-based participatory research and organizational science, comprised of ten types of challenges across four broader categories. Illustrations of challenges and suggestions for addressing them are drawn from two mixed-method, contextual studies of patients with chronic disease in two regions of the US. Results The first major category of challenges was concerned with the researcher-participant partnership, for example, the initial lack of mutual trust and understanding between researchers, patients, and family members. The second category concerned patient characteristics such as cognitive limitations and a busy personal schedule that created barriers to successful data collection. The third concerned research logistics and procedures such as recruitment, travel distances, and compensation. The fourth concerned scientific quality and interpretation, including issues of validity, reliability, and combining data from multiple sources. The two illustrative studies faced both common and diverse research challenges and used many different strategies to address them. Conclusion Collecting less structured data from patients and others in the community is potentially very productive but requires the anticipation, avoidance, or negotiation of various challenges. Future work is necessary to better understand these challenges across different methods and settings, as well as to test and identify strategies to address them

    Modelling Grazing Animal Distributional Patterns Using Multi-Criteria Decision Analysis Techniques

    Get PDF
    Predicting livestock distribution is crucial to reducing livestock impacts on environmentally critical areas. Attempts to model livestock distribution on rangelands have met with varying levels of success. Most of these models described conditions at specific sites and did not work well when they were applied to other sites. In part, the weakness of these models arises from a lack of connection to the spatial arrangement of the study area and the pattern shown by animal distributions. To model the influence of the factors on livestock distribution we developed the Kinetic Resource and Environmental Spatial Systems (KRESS) Modeller. The KRESS Modeler is a multi-criteria decision analysis program that can use GIS layers to predict the suitability of positions in a pasture for animal use

    Implementation, Participation and Evaluation of a Voluntary Water Quality Protection Program for Grazingland Owners and Managers

    Get PDF
    In 1990, California\u27s range livestock industry began working with the state\u27s water quality regulatory agency to develop a voluntary producer participation programme to protect water quality on privately owned grazinglands. In 1995 they implemented a voluntary programme of surface water protection supported by extension education and technical assistance conducted by University of California and USDA Natural Resources Conservation Service. Past studies have shown that education programmes are crucial to voluntary pollution control programmes in agriculture (EPA 1990) and that ranchers will change grazing management practices in response to extension education programmes (Richards and George 1996). The objective of this project was to conduct an extension education programme that facilitated water quality planning and implementation of water quality protection practices by range livestock producers

    Carbon starvation of Pseudomonas aeruginosa biofilms selects for dispersal insensitive mutants.

    Full text link
    BACKGROUND: Biofilms disperse in response to specific environmental cues, such as reduced oxygen concentration, changes in nutrient concentration and exposure to nitric oxide. Interestingly, biofilms do not completely disperse under these conditions, which is generally attributed to physiological heterogeneity of the biofilm. However, our results suggest that genetic heterogeneity also plays an important role in the non-dispersing population of P. aeruginosa in biofilms after nutrient starvation. RESULTS: In this study, 12.2% of the biofilm failed to disperse after 4 d of continuous starvation-induced dispersal. Cells were recovered from the dispersal phase as well as the remaining biofilm. For 96 h starved biofilms, rugose small colony variants (RSCV) were found to be present in the biofilm, but were not observed in the dispersal effluent. In contrast, wild type and small colony variants (SCV) were found in high numbers in the dispersal phase. Genome sequencing of these variants showed that most had single nucleotide mutations in genes associated with biofilm formation, e.g. in wspF, pilT, fha1 and aguR. Complementation of those mutations restored starvation-induced dispersal from the biofilms. Because c-di-GMP is linked to biofilm formation and dispersal, we introduced a c-di-GMP reporter into the wild-type P. aeruginosa and monitored green fluorescent protein (GFP) expression before and after starvation-induced dispersal. Post dispersal, the microcolonies were smaller and significantly brighter in GFP intensity, suggesting the relative concentration of c-di-GMP per cell within the microcolonies was also increased. Furthermore, only the RSCV showed increased c-di-GMP, while wild type and SCV were no different from the parental strain. CONCLUSIONS: This suggests that while starvation can induce dispersal from the biofilm, it also results in strong selection for mutants that overproduce c-di-GMP and that fail to disperse in response to the dispersal cue, starvation

    Adaptation to an amoeba host drives selection of virulence-associated traits in Vibrio cholerae.

    Full text link
    Predation by heterotrophic protists drives the emergence of adaptive traits in bacteria, and often these traits lead to altered interactions with hosts and persistence in the environment. Here we studied adaptation of the cholera pathogen, Vibrio cholerae during long-term co-incubation with the protist host, Acanthamoeba castellanii. We determined phenotypic and genotypic changes associated with long-term intra-amoebal host adaptation and how this impacts pathogen survival and fitness. We showed that adaptation to the amoeba host leads to temporal changes in multiple phenotypic traits in V. cholerae that facilitate increased survival and competitive fitness in amoeba. Genome sequencing and mutational analysis revealed that these altered lifestyles were linked to non-synonymous mutations in conserved regions of the flagellar transcriptional regulator, flrA. Additionally, the mutations resulted in enhanced colonisation in zebrafish, establishing a link between adaptation of V. cholerae to amoeba predation and enhanced environmental persistence. Our results show that pressure imposed by amoeba on V. cholerae selects for flrA mutations that serves as a key driver for adaptation. Importantly, this study provides evidence that adaptive traits that evolve in pathogens in response to environmental predatory pressure impact the colonisation of eukaryotic organisms by these pathogens
    • …
    corecore