Stream phosphorus transport in the Lake Tahoe basin, 1989-1996.

Lake Tahoe is undergoing the initial stages of cultural eutrophication due to human alteration of the airshed and watershed. The lake's switch from nitrogen (N) to phosphorus (P) limitation has been attributed primarily to atmospheric N loading. This places an increased importance on controlling watershed movement of P to the lake. A stream water quality monitoring data set consisting of nine streams in the Lake Tahoe basin has been analyzed to characterize the spatiotemporal variation of P delivery to the lake. This data is from the Lake Tahoe Interagency Monitoring Program (LTIMP), which provides scientific data for planning and regulatory agencies to address environmental problems in the Lake Tahoe basin. Results indicate that P delivery (concentrations, loads) varies greatly at interannual, seasonal, and spatial scales. Annual and seasonal total P (TP) concentrations can vary up to three orders of magnitude in a given stream and are strongly associated with suspended sediment. Particulate P is the major form of P transported by Tahoe streams and was strongly correlated with percent surficial geologic deposits, which are primarily located near streams. Tahoe streams with the highest annual P concentrations often had the lowest annual P loads, and visa versa. P loading is greatest during the spring snowmelt (75% of annual average). Potential watershed parameters influencing P delivery to Lake Tahoe have been identified as precipitation, basin area, basin steepness, and road and human development coverage. Results also suggest that human development impacts on stream P loads are most prevalent during high precipitation years. Identification and quantification of stream sediment and P sources such as streambanks and impervious surface is necessary to aid in watershed restoration efforts.

A highly unsaturated fatty acid predicts carbon transfer between primary producers and consumers.

The factors that regulate energy transfer between primary producers and consumers in aquatic ecosystems have been investigated for more than 50 years. Among all levels of the food web (plants, herbivores, carnivores), the plant-animal interface is the most variable and least predictable link. In hypereutrophic lakes, for example, biomass and energy transfer is often inhibited at the phytoplankton-zooplankton link, resulting in an accumulation of phytoplankton biomass instead of sustaining production at higher trophic levels, such as fish. Accumulation of phytoplankton (especially cyanobacteria) results in severe deterioration of water quality, with detrimental effects on the health of humans and domestic animals, and diminished recreational value of water bodies. We show here that low transfer efficiencies between primary producers and consumers during cyanobacteria bloom conditions are related to low relative eicosapentaenoic acid (20:5omega3) content of the primary producer community. Zooplankton growth and egg production were strongly related to the primary producer 20:5omega3 to carbon ratio. This indicates that limitation of zooplankton production by this essential fatty acid is of central importance at the pelagic producer-consumer interface.

Estimating psychiatric manpower requirements based on patients' needs.

OBJECTIVE: To provide a better understanding of the complexities of estimating psychiatric manpower requirements, the authors describe several approaches to estimation and present a method based on patients' needs. METHODS: A five-step method for psychiatric manpower estimation is used, with estimates of data pertinent to each step, to calculate the total psychiatric manpower requirements for the United States. The method is also used to estimate the hours of psychiatric service per patient per year that might be available under current psychiatric practice and under a managed care scenario. RESULTS: Depending on assumptions about data at each step in the method, the total psychiatric manpower requirements for the U.S. population range from 2,989 to 358,696 full-time-equivalent psychiatrists. The number of available hours of psychiatric service per patient per year is 14.1 hours under current psychiatric practice and 2.8 hours under the managed care scenario. CONCLUSIONS: The key to psychiatric manpower estimation lies in clarifying the assumptions that underlie the specific method used. Even small differences in assumptions mean large differences in estimates. Any credible manpower estimation process must include discussions and negotiations between psychiatrists, other clinicians, administrators, and patients and families to clarify the treatment needs of patients and the roles, responsibilities, and job description of psychiatrists.

A meta-analysis of the freshwater trophic cascade.

The generality of the trophic cascade has been an intensely debated topic among ecologists. We conducted a meta-analysis of 54 separate enclosure and pond experiments that measured the response of the zooplankton and phytoplankton to zooplanktivorous fish treatments. These results provide unequivocal support for the trophic cascade hypothesis in freshwater food webs. Zooplanktivorous fish treatments resulted in reduced zooplankton biomass and increased phytoplankton biomass. The trophic cascade was weakly dampened at the level of the phytoplankton. However, the response of the phytoplankton to the trophic cascade was highly skewed, with very strong responses in slightly more than one-third of the cases and weak responses in the others.

A method for estimating psychiatrist staffing needs in community mental health programs.

Community mental health programs are facing increasing demands to treat and rehabilitate seriously mentally ill patients even as they encounter shortages and burnout of qualified psychiatrists. The authors propose practical and flexible step-by-step guidelines to help such programs estimate current and future psychiatrist staffing needs. The method involves defining the roles of the psychiatrist, negotiating time allocations to be spent providing direct and indirect services, and determining case loads that are mutually agreeable to staff, administrators, and patients. The method can also be used by psychiatrists to negotiate a manageable working arrangement with a community mental health program.

Training residents for community psychiatric practice: guidelines for curriculum development.

There is a critical need to recruit and retain more psychiatrists with the required skills and interest to work with seriously mentally ill and/or socially disadvantaged patients within organized programs in community settings. More residency training programs having the capacity to prepare psychiatrists for community practice can help to meet this need. A consensus definition of the clinical, administrative, consultative and academic areas of contemporary community psychiatric practice developed by the American Association of Community Psychiatrists is used to determine the goals of the training curriculum described in this paper. A comprehensive list of knowledge, skill, and attitude objectives, as well as suggestions for structuring clinical training assignments are provided as guidelines for curriculum development.

Burdens and gratifications of caregiving: appraisal of parental care of adults with schizophrenia.

The caregiving experiences of 60 parents of adults with schizophrenia were investigated for the presence of gratification; the role of the interpersonal caregiver-child relationship; and the effects of burden, gratification, conflict, and intimacy. Results indicate that relationships, as measured by intimacy and conflict, were more highly associated with burden and gratification than were severity of schizophrenic symptoms or degree of caregiving involvement. Implications for therapeutic interventions are discussed.

Perceived costs and benefits of membership in a self-help group: comparisons of members and nonmembers of the Alliance for the Mentally Ill.

We assess the utility of looking at the costs/barriers and benefits/incentives of belonging to an Alliance for the Mentally Ill (AMI) self-help group. Support for bimotivational factors of costs and benefits was found. Comparisons were made between members vs. nonmembers and between more active vs. less active members. Implications for theory and application are discussed.

Community psychiatry training for general psychiatry residents: results of a national survey.

Through its residency training committee, the American Association of Community Psychiatrists (AACP) surveyed residency training programs throughout the country with the goal of discovering what training is currently in place to prepare psychiatrists for work in "community" or "public" settings which serve traditionally underserved populations. The authors summarize the results of the survey and offer suggestions for further steps needed to improve residency training curricula and to address the need for well qualified psychiatrists to choose careers in community psychiatry.

Recruitment, motivation, and reinforcement of preprofessionals for public sector mental health careers.

The labor intensive public mental health system needs to encourage trainees in mental health professions to consider careers in the public sector. Recent evidence is that younger professionals are choosing other career paths following their training. This paper suggests that the availability of relevant training opportunities, positive role models, financial support while in training, and a supportive group of peers are important components of training for public sector careers.

A basic residency curriculum concerning the chronically mentally ill.

In this paper a group of knowledgeable individuals with expertise in psychiatric education present their recommendations for a basic psychiatric residency curriculum concerning the chronically mentally ill. The proposed curriculum consists of knowledge, skill, and attitude educational objectives, as well as clinical experiences, faculty supervision, didactics and seminars, and evaluation mechanisms. Recommendations are also made concerning changes in the Accreditation Council for Graduate Medical Education's Special Requirements for Residency Training in Psychiatry, which would require residency programs to place more emphasis on training to meet the needs of the chronically mentally ill. Obstacles to the implementation of the proposed recommendations are presented and possible solutions are discussed.

Effects of a patient education program in the treatment of schizophrenia.

Two groups of schizophrenic patients were compared to determine the effects of educating patients about schizophrenia and its treatment. One group completed a three-week educational program while the other was involved in the usual ward activities. Comparison of the groups' pretest and posttest scores on three instruments (the Experiential World Inventory, the Scale for the Assessment of Negative Symptoms, and the Knowledge of Illness and Resources Inventory) revealed the experimental group had a significant increase in knowledge of the illness and a significant decrease in the negative symptoms of schizophrenia. No significant difference was found between the groups in change in the positive symptoms of schizophrenia. The results suggest that severely psychiatrically ill patients can learn and retain information and that educating chronic patients about their illness can help improve their functioning.

Climatic forcing: effects of el nino on a small, temperate lake.

Temperature profiles measured regularly for 21 years reveal the interannual differences in winter-to-summer heat gain in Castle Lake, California, a small subalpine lake. Year-to-year changes in large-scale climatic surface forcing, especially the amount of snowfall from February through April (which determines the date of thaw) coupled with the early heating and wind mixing after thaw, causes this interannual variation. The seasonal thermal structure for years in which the lake gains significantly more or less heat than normal-all of the El Niño years and several others-shows that the depth of the mixed layer and the mixing of heat into the stratified thermocline region control the storage of heat. The temperature of the mixed layer does not reflect abnormal thermal storage. Variations in mixing during early spring, which controls the heat content at Castle Lake, may also affect the annual average of the primary productivity.

Allelopathy between zooplankton: a mechanism for interference competition.

The filtering rate of the copepod Diaptomus tyrrelli is reduced in the presence of its potential competitor and predator, Epischura nevadensis, by as much as 60 percent. This effect is caused by a chemical released into the water by Epischura. The chemical does not pass through dialysis tubing with a pore size of 10(4) angstroms, indicating that it is a large molecular weight compound. The reduction in filtering rate is the result of interference competition between two species and may be linked to the evolution of a mechanism for avoiding predation.

Denitrification Studies with 13N-Labeled Nitrate.

Nitrate labeled with (13)N ((13)NO(3)(-)) was produced in a cyclotron by the (16)O(p, alpha)(13)N reaction with protons having energies of 14.5 million electron volts. The (13)NO(3)(-) was used as a tracer for direct quantitative measurements of denitrification rates in soils from flooded rice fields. The (13)N technique provides a new tracer method for the measurement of denitrification rates in natural systems over short time intervals, without changing the concentration of NO(3)(-)in the system.

Ecological aspects of water impoundment in the tropics.

Recognition of the potentially harmful effects of water development in the tropics had led to increasing efforts to assess the environmental impact of such projects prior to construction. Decisions regarding the development or non-development of water resources must be based on sound investigation of both the long-and short-term effects of reservoir construction and operation. The environmental effects of water impoundment vary greatly with the characteristics of the region as well as the type of reservoir to be constructed (area and depth of reservoir, ratio of water inflow to storage). Of major concern are the reduction of reservoir capacity as sediments accumulate behind the dam and the loss of these sediments to downstream agriculture and fisheries. The potential impact of altered flow regimes, siltation, reduction in beach formation and nutrient enrichment at the mouths of rivers, and the possibility of saltwater encroachment should receive careful stdy. A thorough description of the plants and animals to be affected by inundation should be made to determine the possible loss of rare or key organisms as well as the potential development of "nuisance species". Included in this survey should be a detailed study of existing fish and the potential for commercial fishery development in the proposed reservoir. Consideration should be given to vegetation removal in the reservoir basin prior to inundation, since decaying vegetation can result in deoxygenation, formation of hydrogen sulfide, possible development of suitable habitats for undesirable species and snagging of fish nets. Sanitation and land use practices as well as erosion in the watershed surrounding the reservoir must be controlled to prevent accelerated eutrophication caused by increased nutrient loading. Inundation in tropical areas can have serious sociological and human health implications including the increase of diseases, e.g., malaria, schistosomiasis, onchocerciasis, and dysentery, and the probable resettlement and alteration of land use practices. Census information and surveys concerning land use, housing and health standards and the social and economic structure of the community to be affected must be evaluated in order to anticipate and avoid potential problems. The archaeologic, historic, scenic and recreational value of the site to be inundated must also be considered. Studies of the EL Cajón site on the Sula River in Honduras and the Purari River Project in Papua, New Guinea, are utilized as examples in this report.