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Changes in plant inputs under changing atmospheric CO2 can be expected to alter the size and/or functional characteristics of soil microbial communities which can determine whether soils are a C sink or source. Stable isotope probing was used to trace autotrophically fixed 13C into phospholipid fatty acid (PLFA) biomarkers in Mojave Desert soils planted with the desert shrub, Larrea tridentata. Seedlings were pulse-labeled with 13CO2 under ambient and elevated CO2 in controlled environmental growth chambers. The label was chased into the soil by extracting soil PLFAs after labeling at Days 0, 2, 10, 24, and 49. Eighteen of 29 PLFAs identified showed 13C enrichment relative to nonlabeled control soils. Patterns of PLFA enrichment varied temporally and were similar for various PLFAs found within a microbial functional group. Enrichment of PLFA 13C generally occurred within the first 2 days in general and fungal biomarkers, followed by increasingly greater enrichment in bacterial biomarkers as the study progressed (Gram-negative, Gram-positive, actinobacteria). While treatment CO2 level did not affect total PLFA-C concentrations, microbial functional group abundances and distribution responded to treatment CO2 level and these shifts persisted throughout the study. Specifically, ratios of bacterial-to-total PLFA-C decreased and fungal-to-bacterial PLFA-C increased under elevated CO2 compared with ambient conditions. Differences in the timing of 13C incorporation into lipid biomarkers coupled with changes in microbial functional groups indicate that microbial community characteristics in Mojave Desert soils have shifted in response to long-term exposure to increased atmospheric CO2. [ABSTRACT FROM AUTHOR]

Changes in plant inputs under changing atmospheric CO2 can be expected to alter the size and/or functional characteristics of soil microbial communities which can determine whether soils are a C sink or source. Stable isotope probing was used to trace autotrophically fixed 13C into phospholipid fatty acid (PLFA) biomarkers in Mojave Desert soils planted with the desert shrub, Larrea tridentata. Seedlings were pulse-labeled with 13CO2 under ambient and elevated CO2 in controlled environmental growth chambers. The label was chased into the soil by extracting soil PLFAs after labeling at Days 0, 2, 10, 24, and 49. Eighteen of 29 PLFAs identified showed 13C enrichment relative to nonlabeled control soils. Patterns of PLFA enrichment varied temporally and were similar for various PLFAs found within a microbial functional group. Enrichment of PLFA 13C generally occurred within the first 2 days in general and fungal biomarkers, followed by increasingly greater enrichment in bacterial biomarkers as the study progressed (Gram-negative, Gram-positive, actinobacteria). While treatment CO2 level did not affect total PLFA-C concentrations, microbial functional group abundances and distribution responded to treatment CO2 level and these shifts persisted throughout the study. Specifically, ratios of bacterial-to-total PLFA-C decreased and fungal-to-bacterial PLFA-C increased under elevated CO2 compared with ambient conditions. Differences in the timing of 13C incorporation into lipid biomarkers coupled with changes in microbial functional groups indicate that microbial community characteristics in Mojave Desert soils have shifted in response to long-term exposure to increased atmospheric CO2. [ABSTRACT FROM AUTHOR]

Elevated atmospheric carbon dioxide (CO2) has the potential to alter soil carbon (C) and nitrogen (N) cycling in arid ecosystems through changes in net primary productivity. However, an associated feedback exists because any sustained increases in plant productivity will depend upon the continued availability of soil N. We took soils from under the canopies of major shrubs, grasses, and plant interspaces in a Mojave Desert ecosystem exposed to elevated atmospheric CO2 and incubated them in the laboratory with amendments of labile C and N to determine if elevated CO2 altered the mechanistic controls of soil C and N on microbial N cycling. Net ammonification increased under shrubs exposed to elevated CO2, while net nitrification decreased. Elevated CO2 treatments exhibited greater fluxes of N2O–N under Lycium spp., but not other microsites. The proportion of microbial/extractable organic N increased under shrubs exposed to elevated CO2. Heterotrophic N2-fixation and C mineralization increased with C addition, while denitrification enzyme activity and N2O–N fluxes increased when C and N were added in combination. Laboratory results demonstrated the potential for elevated CO2 to affect soil N cycling under shrubs and supports the hypothesis that energy limited microbes may increase net inorganic N cycling rates as the amount of soil-available C increases under elevated CO2. The effect of CO2 enrichment on N-cycling processes is mediated by its effect on the plants, particularly shrubs. The potential for elevated atmospheric CO2 to lead to accumulation of NH4+ under shrubs and the subsequent volatilization of NH3 may result in greater losses of N from this system, leading to changes in the form and amount of plant-available inorganic N. This introduces the potential for a negative feedback mechanism that could act to constrain the degree to which plants can increase productivity in the face of elevated atmospheric CO2. [ABSTRACT FROM AUTHOR]

Identifying soil microbial responses to anthropogenically driven environmental changes is critically important as concerns intensify over the potential degradation of ecosystem function. We assessed the effects of elevated atmospheric CO2 on microbial carbon (C) and nitrogen (N) cycling in Mojave Desert soils using extracellular enzyme activities (EEAs), community-level physiological profiles (CLPPs), and gross N transformation rates. Soils were collected from unvegetated interspaces between plants and under the dominant shrub ( Larrea tridentata) during the 2004–2005 growing season, an above-average rainfall year. Because most measured variables responded strongly to soil water availability, all significant effects of soil water content were used as covariates to remove potential confounding effects of water availability on microbial responses to experimental treatment effects of cover type, CO2, and sampling date. Microbial C and N activities were lower in interspace soils compared with soils under Larrea, and responses to date and CO2 treatments were cover specific. Over the growing season, EEAs involved in cellulose (cellobiohydrolase) and orthophosphate (alkaline phosphatase) degradation decreased under ambient CO2, but increased under elevated CO2. Microbial C use and substrate use diversity in CLPPs decreased over time, and elevated CO2 positively affected both. Elevated CO2 also altered microbial C use patterns, suggesting changes in the quantity and/or quality of soil C inputs. In contrast, microbial biomass N was higher in interspace soils than soils under Larrea, and was lower in soils exposed to elevated CO2. Gross rates of NH4+ transformations increased over the growing season, and late-season NH4+ fluxes were negatively affected by elevated CO2. Gross NO3− fluxes decreased over time, with early season interspace soils positively affected by elevated CO2. General increases in microbial activities under elevated CO2 are likely attributable to greater microbial biomass in interspace soils, and to increased microbial turnover rates and/or metabolic levels rather than pool size in soils under Larrea. Because soil water content and plant cover type dominates microbial C and N responses to CO2, the ability of desert landscapes to mitigate or intensify the impacts of global change will ultimately depend on how changes in precipitation and increasing atmospheric CO2 shift the spatial distribution of Mojave Desert plant communities. [ABSTRACT FROM AUTHOR]

We investigated the effects of changes in soil C and N availability on N mineralization, nitrification, denitrification, NH3 volatilization, and soil respiration in the Mojave Desert. Results indicate a C limitation to microbial N cycling. Soils from underneath the canopies of Larrea tridentata (DC.) Cov., Pleuraphis rigida Thurber, and Lycium spp. exhibited higher rates of CO2 flux, lower rates of NH3 volatilization, and a decrease in inorganic N (NH4+-N and NO3--N) with C addition. In addition to C limitation, soils from plant interspaces also exhibited a N limitation. Soils from all locations had net immobilization of N over the course of a 15-day laboratory incubation. However, soils from interspaces had lower rates of net nitrification and potential denitrification compared to soils from under plant canopies. The response to changes in C availability appears to be a short-term increase in microbial immobilization of inorganic N. Under controlled conditions, and over a longer time period, the effects of C and N availability appear to give way to larger differences due to spatial location. These findings have implications for ecosystems undergoing changes in soil C and N availability due to such processes as desertification, exotic species invasions, or elevated atmospheric CO2 concentration. [ABSTRACT FROM AUTHOR]

Elevated atmospheric carbon dioxide (CO2) has the potential to alter soil carbon (C) and nitrogen (N) cycling in arid ecosystems through changes in net primary productivity. However, an associated feedback exists because any sustained increases in plant productivity will depend upon the continued availability of soil N. We took soils from under the canopies of major shrubs, grasses, and plant interspaces in a Mojave Desert ecosystem exposed to elevated atmospheric CO2 and incubated them in the laboratory with amendments of labile C and N to determine if elevated CO2 altered the mechanistic controls of soil C and N on microbial N cycling. Net ammonification increased under shrubs exposed to elevated CO2, while net nitrification decreased. Elevated CO2 treatments exhibited greater fluxes of N2O–N under Lycium spp., but not other microsites. The proportion of microbial/extractable organic N increased under shrubs exposed to elevated CO2. Heterotrophic N2-fixation and C mineralization increased with C addition, while denitrification enzyme activity and N2O–N fluxes increased when C and N were added in combination. Laboratory results demonstrated the potential for elevated CO2 to affect soil N cycling under shrubs and supports the hypothesis that energy limited microbes may increase net inorganic N cycling rates as the amount of soil-available C increases under elevated CO2. The effect of CO2 enrichment on N-cycling processes is mediated by its effect on the plants, particularly shrubs. The potential for elevated atmospheric CO2 to lead to accumulation of NH4+ under shrubs and the subsequent volatilization of NH3 may result in greater losses of N from this system, leading to changes in the form and amount of plant-available inorganic N. This introduces the potential for a negative feedback mechanism that could act to constrain the degree to which plants can increase productivity in the face of elevated atmospheric CO2. [ABSTRACT FROM AUTHOR]

Baylisascaris procyonis is the common intestinal nematode of the raccoon and is well-recognized as a cause of visceral, ocular, and neural larva migrans in many species of wild and domestic birds and mammals, including humans. To develop data on the prevalence of B. procyonis in Orange County, California, 800 distinct raccoon latrine sites were sampled in 4 spatial zones from 15 January to 31 December 2000. Counts of fecal eggs per gram (EPG) were determined and evaluated with reference to spatial zone and season of collection. No significant differences in EPG were noted among the spatial zones. However, EPG exhibited a significant rise (37,730 +/- 1,865) in the fall and a significant decline (26,204 +/- 1,446) in the winter (ANOVA, P = 0.045). The overall egg prevalence was 100%, and the overall mean EPG was 30,265 +/- 867.

Baylisascaris procyonis is one of the common nematodes of the raccoon (Procyon lotor), being well recognized as a cause of visceral, ocular, and neural larval migrans in many species of wild and domestic birds and mammals, including humana. Between January 15 and December 31, 2000 in Orange County, CA, 640 raccoons (P. lotor) were live-trapped in four spatial distributions zones, and B. procyonis egg shedding prevalence and fecal egg per gram (EPG) counts were determined in relation to spatial distribution zones, season of the year, age, and sex. Egg shedding prevalence rates were not statistically different between zones, but the EPG count in the primarily residential Zone D differed significantly from other zones. Egg shedding prevalence and EPG counts exhibited a significant rise in the fall and decline in the winter and were significantly higher in juvenile and male raccoons than in adult and female raccoons. The overall fecal egg shedding prevalence was 72.0 +/- 1.8% (461/640), and the overall EPG count was 27,982 +/- 1,006.

Background and Objectives: Public health complements the care physicians provide to patients. Few residencies, with the exception of preventive medicine residencies, offer trainees the opportunity to obtain a public health degree. The University of California, San Francisco-Fresno (UCSF-Fresno) Family Practice Program and California State University-Fresno (CSU-Fresno) spearheaded the creation of a combined residency/MPH program at the UCSF-Fresno Medical Education Program., Methods: We developed a combined residency/MPH program that allows family practice residents to obtain an MPH degree during their residency training years. We describe the development process, which included initiation of the program, setting goals and objectives, identifying MPH course content and funding, and selecting applicants for entry into the program., Results: The program was successfully funded, and the course content was developed. Participant selection, registration, and enrollment procedures have now been developed. Performance standards have been established, and scheduling conflicts have been addressed. The program has thus far enrolled 29 residents and faculty. Nearly one third have dropped out of the MPH component of the program, mostly because of the workload involved in simultaneous residency and MPH training., Conclusions: Other training programs can replicate a combined residency/MPH program if a strong relationship with a nearby university offering a MPH degree can be forged. The experience at UCSF-Fresno can help guide others contemplating a combined residency/MPH program.

The cultural significance of recent changes in medicine and advances in biotechnology can hardly be overstated. Such have stirred fresh interest in the moral foundations of ethical decision-making and lively debate has ensued as well over the basis of human dignity. Largely divorced from the distinctive moral and ethical commitments that once informed and directed medical practice, modern secular notions of bioethics collapse frequently into human philosophical models of rights and justice. The project of Western medicine now continues within the cultural framework of a radical postmodern agenda that calls for the critical deconstruction and absolute relativizing of all knowledge, and the thorough secularization of the public square. Truth, once understood as a fixed expression of a fundamental reality, has been eschewed in favor of personal preference, subjective experience, private interpretation, and radical perspectivism. Perhaps the greatest challenge facing contemporary culture is that of arriving at a clear and convincing consensus on what constitutes moral surety as well as agreement on what knowledge can serve as an adequate foundation for living the moral life. Having abandoned the reality of divine involvement in the creation and sustenance of human life, contemporary culture now toys with what it means to be human without God. Increasingly popular is the view that whether one possesses dignity or not turns on the question of suffering. Under modern parlance it is simply undignified to suffer. Suffering, somehow, is believed to reduce a person to a state that is incompatible with dignity. Therefore, it should come as no surprise that one of the most pressing social issues today involves the effort to legalize physician-assisted suicide--a project based upon the view that people ought to "die with dignity." In California this view is embodied in Assembly Bill 1592, The "Death with Dignity Act." It is intended to establish California as the second state in the United States to legalize physician-assisted suicide. Patterned closely after Oregon's groundbreaking law, the California bill provides for a terminally ill patient to end his or her own life when certain conditions exist. The purpose of this paper is to review the historical development of California Assembly Bill 1592. An evaluation of both the content of this bill and the process by which it was introduced to the California State Assembly will be offered. The student of bioethics will here find that the usual arguments in support of physician-assisted suicide in the United States, as well as euthanasia in the Netherlands, have been employed in support of AB1592; namely suffering and autonomy. Given the rather predictable pattern of argument advanced by advocates of physician-assisted suicide and euthanasia, this discussion will prove useful for those who wish to offer an informed and sensitive Christian response to similar legislative efforts in other states and countries.

Background: To improve asthma disease management, the National Asthma Education Program (NAEP) Expert Panel published Guidelines for the Diagnosis and Management of Asthma in 1991., Objectives: To compare the current status of asthma disease management among patients in a large health maintenance organization with the NAEP guidelines and to identify the factors that may be associated with medical care (eg, emergency department visits and hospital admissions) and adherence to the guidelines., Methods: Analyses of 1996 survey data from 5580 members with asthma (age range, 14 to 65 years) covered by a major health maintenance organization in California (Health Net)., Results: In general, adherence to NAEP guidelines was poor. Seventy-two percent of respondents with severe asthma reported having a steroid inhaler, and of those, only 54% used it daily. Only 26% of respondents reported having a peak flowmeter, and of those, only 16% used it daily. Age (older), duration of asthma (longer), increasing current severity of disease, and treatment by an asthma specialist correlated with daily use of inhaled steroids. Ethnicity (African American and Hispanic) correlated negatively with inhaled steroid use but positively with emergency department visits and hospital admissions for asthma. Increasing age and treatment by an asthma specialist were also identified as common factors significantly related to the daily use of a peak flowmeter and, interestingly, to overuse of beta2-agonist metered-dose inhalers., Conclusions: Although the NAEP guidelines were published 7 years ago, compliance with the guidelines was low. It was especially poor for use of preventive medication and routine peak-flow measurement. Furthermore, the results showed that asthma specialists provided more thorough care than did primary care physicians in treating patients with asthma. Combining the results of the regression analyses revealed that some of the variation in rates of emergency department visits and hospitalizations among some subpopulations can be explained by the underuse of preventive medication. This study serves the goal of documenting the quality of care and services currently provided to patients with asthma through a large health maintenance organization and provides baseline information that can be used to design and assess effective population-based asthma disease management intervention programs.

The Federal Special Supplemental Food Program for Women, Infants and Children provides nutritious foods and dietary counselling to low income women and children with a medically certified nutritional risk. The Public Health Foundation, a large WIC agency in Los Angeles, observed declining breastfeeding rates among Indochinese participants. We interviewed 110 Cambodian, ethnic Chinese and Vietnamese WIC participants about their infant feeding decisions and experience. These women believed that formula was superior to breastmilk for a number of reasons, some related to the Asian humoral medical system. The women described 'excessive cooling' during childbirth that they hoped to counter-balance by consuming humorally hot foods for 100 days post partum. A hot maternal diet was thought to produce unhealthy breastmilk after 1 month, so the women preferred using infant formula, perceived to be stable and more nourishing than breastmilk. The WIC Program is using these and other findings to make breastfeeding more attractive to Southeast Asians.