1,514 research outputs found
Geology, Characteristics, and Resource Potential of the Low-Temperature Geothermal System Near Midway, Wasatch County, Utah
Recent awareness of the finite nature of fossil-fuel resources has resulted in an increased interest in alternate sources of energy such as geothermal. To evaluate the geothermal energy potential of the hot springs system near Midway, Wasatch Co., Utah, consideration was given to heat flow, water chemistry, and structural controls.
Abnormal heat flow was indicated qualitatively by snow-melt patterns and quantitatively by heat-flow measurements that were obtained from two of four temperature-gradient wells drilled in the area. These measurements indicated that the area north of the town of Midway is characterized by heat flow equal to 321.75 mW/m2, which is over four times the value generally considered as normal heat flow.
Chemical analyses of water from six selected thermal springs and wells were used in conjunction with the silica and Na-K-Ca geothermometers to estimate the reservoir temperature of the thermal system. Because the calculated temperature was more than 25 degrees C above the maximum observed temperature, a mixing model calculation was used to project an upper limit for the reservoir temperature. Based on these calculations, the system has a reservoir temperature ranging from 46 to 125 degrees C.
Structural information obtained from published from published geologic maps of the area and from an unpublished gravity survey, enabled two models to be developed for the system. The first model, based geologic relationships in the mountains to the north and west of Midway, assumes that the heat for the thermal system comes from a relatively young intrusive or related hydrothermal convection system in the vicinity of the Mayflower mine. Meteoric waters would be heated as they approach the heat source and then move laterally to the south through faults and fractures in the rocks. These thermal waters then rise to the surface through fractures in the crest of an anticline underneath the Midway area. The second model, based on the gravity survey, assumes an igneous intrusion directly beneath Midway as the heat source. The first model is considered more likely.
The Midway geothermal system is a low temperature resource, suitable for space-heating and other direct-use applications
Should home-based HIV testing and counseling services be offered periodically in programs of ARV treatment as prevention? A case study in Likoma (Malawi).
To reduce HIV incidence, prevention programs centered on the use of antiretrovirals require scaling-up HIV testing and counseling (HTC). Home-based HTC services (HBHTC) increase HTC coverage, but HBHTC has only been evaluated during one-off campaigns. Two years after an initial HBHTC campaign ("round 1"), we conducted another HBHTC campaign ("round 2") in Likoma (Malawi). HBHTC participation increased during round 2 among women (from 74 to 83%, P < 0.01). New HBHTC clients were recruited, especially at ages 25 and older. Only 6.9% of women but 15.9% of men remained unreached by HBHTC after round 2. HIV prevalence during round 2 was low among clients who were HIV-negative during round 1 (0.7%), but high among women who received their first ever HIV test during round 2 (42.8%). The costs per newly diagnosed infection increased significantly during round 2. Periodically conducting HBHTC campaigns can further increase HTC, but supplementary interventions to enroll individuals not reached by HBHTC are needed
The Likoma Network Study: Context, data collection and initial results
The extent and structure of sexual networks have important consequences for the spread of sexually transmitted diseases such as HIV. However, very few datasets currently exist that allow a detailed investigation of sexual networks in sub-Saharan African settings where HIV epidemics have become generalized. In this paper, we describe the context and methods of the Likoma Network Study (LNS), one of the few studies that have collected extensive information on sexual networks in sub-Saharan Africa. We start by reviewing theoretical arguments and empirical studies emphasizing the importance of network structures in the epidemiology of HIV and other sexually transmitted infections (STI). The island setting of this study is described, and we argue that the choice of an island as a research site limited potential biases that may make the collection of sexual network data difficult. We then document our empirical strategy for the collection of sexual network data and the subsequent identification of sexual network partners. A description of the protocol for the collection of biomarker data (HIV infection) is provided. Finally, we present initial results relating to the socioeconomic context of the island, the size and composition of sexual networks, the quality of the sexual network data, the determinants of successful contact tracing during the LNS, and the prevalence of HIV in the study population.HIV risk factors, HIV transmission, Malawi, sexual behavior, sexual networks
Aquaculture Performance Comparison of Sunshine Bass, Palmetto Bass, and White Bass
Aquaculture performance of phase II and phase III sunshine bass (a female white bass Morone chrysops Ă male striped bass M. saxatilis), palmetto bass (a female striped bass Ă male white bass), and white bass were evaluated in separate 12-week yield trials conducted in indoor recirculating-water systems. Phase II sunshine bass, palmetto bass, and white bass had mean initial weights of 40.0 g, 39.7 g, and 41.0 g, respectively. A diet containing 40.2% crude protein (CP) was fed to fish twice daily at a rate of 3% body weight/d. At the end of the trial, sunshine bass and white bass had mean weights of 124.2 g and 126.0 g, respectively and were significantly larger than palmetto bass (93.5 g mean weight). Phase II sunshine bass and white bass outperformed palmetto bass by having higher relative growth (h), mean daily growth, and relative weight, as well as better feed conversion ratios (weight of food fed/weight gained). Survival was 100% for all three taxonomic groups. In the phase III study, mean initial weights for sunshine bass (177.5 g) and palmetto bass (185.9 g) were similar but significantly greater than the mean initial weight of white bass (153.8 g). In this trial, fish were fed a floating trout chow (44.1% CP) to satiation twice per day. At the termination of the study, sunshine bass (611.1 g) and palmetto bass (517.8 g) had significantly greater mean weights than white bass (254.4 g). Significant differences among all three taxonomic groups were found for h and for mean daily growth rate. Both crosses of hybrid striped bass had lower feed conversion ratios when compared with white bass. Relative weight values (ratio of a fish\u27s weight to the weight of a standard fish of the same length) for sunshine bass were significantly greater than values for palmetto bass and white bass. Survival rates ranged from 98% to 100% for the three taxonomic groups. Differences were not detected between sunshine bass and palmetto bass for eviscerated percentage, headed and eviscerated percentage, or dressout percentage. Sunshine bass outperformed palmetto bass at phase II and phase III sizes under the conditions of this study
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Electricity Network Scenarios for Great Britain in 2050
The next fifty years are likely to see great developments in the technologies deployed in electricity systems, with consequent changes in the structure and operation of power networks. This paper, which forms a chapter in the forthcoming book Future Electricity Technologies and Systems, develops and presents six possible future electricity industry scenarios for Great Britain, focussed on the year 2050. The paper draws upon discussions of important technologies presented by expert authors in other chapters of the book to consider the impact of different combinations of key influences on the nature of the power system in 2050. For each scenario there is a discussion of the effects of the key parameters, with a description and pictorial illustration. Summary tables identify the role of the technologies presented in other chapters of the book, and list important figures of interest, such as the capacity and energy production of renewable generation technologies
Howard R. DuFour: The Cold War Aerospace Technology History Project (Interview 1)
James Kohler interviewed Howard DuFour on May 17, 2006 for the Cold War Aerospace Technologies History Project. In the interview Mr. DuFour discusses his role in the development of military technology during the Cold War. This is the first of three interviews with Mr. DuFour
The Mature Adults Cohort of the Malawi Longitudinal Study of Families and Health (MLSFH-MAC)
Cohort purpose: The Mature Adults Cohort of the Malawi Longitudinal Study of Families and Health (MLSFH-MAC) contributes to global aging studies by providing a rare opportunity to study the processes of individual and population aging, the public health and social challenges associated with aging and the coincident shifts in disease burdens, in a low-income, high HIV prevalence, sub-Saharan African (SSA) context.
Design and Measures: The MLSFH-MAC is a population-based cohort study of mature adults aged 45 years and older living in rural communities in three districts in Malawi (Mchinji, Balaka and Rumphi). Initial enrollment at baseline is 1,266 individuals in 2012. MLSFH-MAC follow-ups were in 2013, 2017, and 2018. Survey instruments cover aging-related topics such as cognitive and mental health, NCDs and related health literacy, subjective survival expectations, measured biomarkers including HIV, grip strength, hypertension, fasting glucose, BMI, a broad range of individual- and household-level social and economic information, a 2018 qualitative survey of mature adults and community officials, 2019 surveys of village heads, health care facilities and health care providers in the MLSFH-MAC study areas.
Unique features: MLSFH-MAC is a data resource that covers 20 years of the life course of cohort members and provides a wealth of information unprecedented for aging studies in a low-income SSA context that broadly represents the socioeconomic environment of millions of individuals in south-eastern Africa. Among these are the longitudinal population-based data on depression and anxiety using clinically-validated instruments. MLSFH-MAC is also vanguard in measuring longitudinal changes in cognitive health among older individuals in SSA. Complemented by contextual and qualitative information, the extensive MLSFH-MAC data facilitate a life-course perspective on aging that reflects the dynamic and distinct settings in which people reach older ages in SSA LICs. Across many domains, MLSFH-MAC also allows for comparative research with global aging studies through harmonized measures and instruments.
Collaboration and data access: Public-use version of the 2012 (baseline) MLSFH-MAC data can be requested at http://www.malawi.pop.upenn.edu. Sharing of additional MLSFH-MAC data is currently possible as part of collaborative research projects (if not overlapping with ongoing research projects, and subject to a Data Use Agreement)
Curtailing COVID-19 on a Dollar-a-Day in Malawi: Implications for the Ongoing Pandemic
Utilizing population-based data from the COVID-19 phone survey (N=2,262$) of the Malawi Longitudinal Study of Families and Health (MLSFH) collected during June 2nd--August 17th, 2020, we investigate behavioral, economic and social responses COVID-19 and focus on the crucial role that community leadership and trust in institutions play towards shaping these responses. We argue that the effective response of Malawi to limit the spread of the virus was facilitated by the engagement of local leaders to mobilize communities to adapt and adhere to COVID-19 prevention strategies. Village heads (VHs) played pivotal role in shaping individual\u27s knowledge about the pandemic and the adaption of preventive health behaviors and were crucial for mitigating the negative economic and health consequences of the pandemic. We further show that trust in institutions is of particular importance in shaping individuals\u27 behavior during the pandemic, and these findings highlight the pivotal role of community leadership in fostering better compliance and adoption of public health measures essential to contain the virus. Overall, our findings point to distinctive patterns of pandemic response in a low-income sub-Saharan African rural population that emphasized local leadership as mediators of public health messages and policies. These lessons from the first pandemic wave remain relevant as in many low-income countries behavioral responses to COVID-19 will remain the primary prevention strategy for a foreseeable future
Artist-In-Residence Recital
Program listing performers and works performe
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