7 resultados para species and community

em DigitalCommons@The Texas Medical Center


Relevância:

100.00% 100.00%

Publicador:

Resumo:

A community bioassay of copper was performed using benthic macroinvertebrates colonized on multiplate substrate samplers. Five copper concentrations ranging from 0.080-2.20 mg/l total copper were administered to five artificial streams by a Mount and Brungs proportional dilutor. Free copper ion as Cu('++) ranged from .002-.053 mg/l. A sixth stream received no copper and served as a control. Substrates were sampled at days 0, 14, and 28, and the results were used to compare 13 indices used or proposed to assess aquatic environmental impact. Sensitivity of the indices to changes in communities with respect to concentration and time was the basis for the comparison.^ Results indicated that all of the 8 diversity or richness indices tested gave approximately the same result (with the exception of number of species); they increased over the first 2-3 concentrations, then declined. Included among these was the Shannon index which gave false positive results, i.e., it increased, indicating enrichment, when in fact perturbation had occurred. This result was due to the disproportionate effect on the most abundant taxa, which caused a more even distribution of individuals among species. Number of species and individuals declined with increased concentration and time, with only one exception in the case of species, indicating perturbation.^ Results of five community comparison indices were varied at day 14 but by day 28 the results indicated a clear, nearly monotonic, trend due to copper impact. It was assumed that day 28 observations, though probably still changing, were nearer stability than at day 14 and therefore more representative of natural conditions. The changes in community comparison indices showed good agreement at 28 days and reflected the general decline in species and individuals. No single community comparison index could be set apart as superior to the others. ^

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This dissertation is an examination of the ideals and practices that have characterized Western culture's relationship to the natural world. The conventional approach, depicted by some of the most prominent ecological publications of recent years, criticizes the Western tradition for both its ideals and practices. The ideals are assumed to be best represented in Western philosophy and religion and both of these sources have been indicted. These ideals are coupled with the Western way of life that is equally indicted as exploitive and destructive. Author, professor and farmer, Wendell Berry, offers an alternative to these indictments. Berry insists that a theme, advocating ecological accountability, runs through some of the West's most significant literature and that Western tradition contains a practice that can support these ecological principles. ^

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This study explored the health, education, social assets, needs, attitudes, and behaviors of residents of Ferrocarril #4, a small urban community in Tamaulipas, Mexico. A collaborative Participatory Action Research approach was used to emphasize community involvement. Using Triangulation to ensure validity, qualitative methods included key informant in depth interviews, participant observation and participatory discussion groups with women and men. A personal interview with a probability sample of women was done. The median age of interviewees was 37 years. The majority was married or had a partner. Over half of respondents completed grades 6-9. Employed women (25%) earned a median weekly salary equivalent to ∼56 USD. Women with health insurance (67.7%) were covered mainly through Social Security and Seguro Popular. One in 5 reported bad health. Barriers to care were primarily money and transportation. To improve health care, women wanted a full service clinic in or close to the community and affordable health care. Socially, 28% of respondents had no close friends in the community and most did not participate in beneficial community activities. Many women did not socialize with others and help from neighbors was situational. Primary school teachers lacked parental support and it interfered with classroom efforts. Healthy community discussion groups focused on personal and environmental hygiene and safety. Valuable assets exist in the community. To date, collaborative efforts resulted in a school First Aid station, a school nurse visit weekly, posting of emergency contact phone numbers in the school and community center, and development of a student health information form. ^

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Little is known about HIV stigma in Nepal. Findings from other parts of the world suggest that HIV related stigma acts as a limiting factor for People Living with HIV & AIDS (PLHAs) from accessing needed health care and the subsequent psychological outcomes make PLHAs and their immediate family members more vulnerable. The purpose of this study is to understand and describe Nepalese PLHA's and community peoples' experiences regarding sources, types, causes and mechanism of HIV-associated stigma. This study aimed to best utilize the existing data. Study participants were recruited through local Community Based Organizations working in the field of HIV. The data, collected in the form of focus group discussions in workshop settings, were coded and analyzed. Study has revealed key issues related to HIV stigma in Nepal: hierarchy of stigma, denial and rejection, death as a form of punishment and Mumbaiya disease. A conceptual model was developed to explain the HIV stigma in Nepal. Our hope is that this finding, stigma being a contextual variable, will be helpful in triggering a novel public health discourse in the field of HIV stigma in Nepal, which will eventually be helpful for developing policies and interventions to eliminate HIV-associated stigma.^

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Hospital care is the largest component of the health care sector. This industry is made up of for profit hospital (FPH) organizations, not for profit (NFP) hospitals, and government (GOV) run hospital facilities. Objectives of this analysis were: (a) to conduct a literature review on NFP hospital legislation at the state level in Texas and at the federal level in the broader U.S.; and (b) to describe the types of charity care and community benefits currently being provided: by NFP hospitals compared to FPH hospitals and GOV hospitals; by hospitals geographic proximity to the Texas-Mexico border; and by hospital community type (rural, suburban, and urban); and (c) propose specific policy changes that may be needed to improve the current Texas State statute. Methods. In describing the historical and current policy context of NFP hospital legislation in the United States, federal legislation was reviewed from 1913 to the present and Texas State legislation was reviewed from 1980 to the present. In describing the provision of charity care, data from the 2008 Annual Cooperative Hospital Survey were examined by hospital organizational type, size, proximity to the border, and community type using linear regression and chi-squared tests to assess differences in charity care and community benefits. Results. The data included 123 NFP hospitals, 114 GOV hospitals, and 123 FPH. Results. Small sized (p<0.001) and medium sized (p<0.001) NFP hospitals provide a greater percent of total charity care when compared to FPH hospitals and to both GOV and FPH hospitals respectively; however, no significant difference in total charity care was found among large sized NFP hospitals when compared to FPH hospitals alone (p=.345) and both GOV and FPH facilities (p=.214). The amount of charity care provided was not found to be different based on proximity to the border or community type. Community benefit planning and budgeting was found to be similar regardless of community type and proximity to the border. Conclusion. No differences in charity care in Texas were found for large sized NFP hospitals compared to FPH and GOV hospitals. Contrary to widely held beliefs, this study did not find the border region to provide a greater amount of charity care or bad debt. Charity care also did not vary by community type. These findings underscore the need for continued collection of transparent data from all hospitals in order to provide policy makers and consumers with information on utilization trends to ensure benefits are being provided to the community. Policy changes or revoking tax-benefits may occur as charity care utilization declines with the implementation of health reform in the next few years.^

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Glioblastoma multiforme (GBM) is the most common and aggressive primary brain tumor with poor prognosis due in part to drug resistance and high incidence of tumor recurrence. The drug resistant and cancer recurrence phenotype may be ascribed to the presence of glioblastoma stem cells (GSCs), which seem to reside in special stem-cell niches in vivo and require special culture conditions including certain growth factors and serum-free medium to maintain their stemness in vitro. Exposure of GSCs to fetal bovine serum (FBS) can cause their differentiation, the underlying mechanism of which remains unknown. Reactive oxygen species (ROS) play an important role in normal stem cell differentiation, but their role in affecting cancer stem cell fate remains unclear. Whether the metabolic characteristics of GSCs are different from other glioblastoma cells and can be targeted are also unknown. In this study, we used several stem-like glioblastoma cell lines derived from clinical tissues by typical neurosphere culture system or orthotopic xenografts, and showed that addition of fetal bovine serum to the medium induced an increase of ROS, leading to aberrant differentiation and decreases of stem cell markers such as CD133. We found that exposure of GSCs to serum induced their differentiation through activation of mitochondrial respiration, leading to an increase in superoxide (O2-) generation and a profound ROS stress response manifested by upregulation of oxidative stress response pathway. This increase in mitochondrial ROS led to a down-regulation of molecules including SOX2, and Olig2, and Notch1 that are important for stem cell function and an upregulation of mitochondrial superoxide dismutase SOD2 that converts O2- to H2O2. Neutralization of ROS by antioxidant N-acetyl-cysteine in the serum-treated GSCs suppressed the increase of superoxide and partially rescued the expression of SOX2, Olig2, and Notch1, and prevented the serum-induced differentiation phenotype. Additionally, GSCs showed high dependence on glycolysis for energy production. The combination of a glycolytic inhibitor 3-BrOP and a chemotherapeutic agent BCNU depleted cellular ATP and inhibited the repair of BCNU-induced DNA damage, achieving strikingly synergistic killing effects in drug resistant GSCs. This study uncovers the metabolic properties of glioblastoma stem cells and suggests that mitochondrial function and cellular redox status may profoundly affect the fates of glioblastoma stem cells via a ROS-mediated mechanism, and that the active glycolytic metabolism in cancer stem cells may provide a biochemical basis for developing novel therapeutic strategies to effectively eliminate GSCs.