953 research outputs found

    Design strategies for the International Space University's variable gravity research facility

    Get PDF
    A variable gravity research facility named 'Newton' was designed by 58 students from 13 countries at the International Space University's 1989 summer session at the Universite Louis Pasteur, Strasbourge, France. The project was comprehensive in scope, including a political and legal foundation for international cooperation, development and financing; technical, science and engineering issues; architectural design; plausible schedules; and operations, crew issues and maintenance. Since log-term exposure to zero gravity is known to be harmful to the human body, the main goal was to design a unique variable gravity research facility which would find a practical solution to this problem, permitting a manned mission to Mars. The facility would not duplicate other space-based facilities and would provide the flexibility for examining a number of gravity levels, including lunar and Martian gravities. Major design alternatives included a truss versus a tether based system which also involved the question of docking while spinning or despinning to dock. These design issues are described. The relative advantages or disadvantages are discussed, including comments on the necessary research and technology development required for each

    The International Space University's variable gravity research facility design

    Get PDF
    A manned mission to Mars will require long travel times between Earth and Mars. However, exposure to long-duration zero gravity is known to be harmful to the human body. Some of the harmful effects are loss of heart and lung capacity, inability to stand upright, muscular weakness and loss of bone calcium. A variable gravity research facility (VGRF) that would be placed in low Earth orbit (LEO) was designed by students of the International Space University 1989 Summer Session held in Strasbourg, France, to provide a testbed for conducting experiments in the life and physical sciences in preparation for a mission to Mars. This design exercise was unique because it addressed all aspects concerning a large space project. The VGRF design was described which was developed by international participants specializing in the following areas: the politics of international cooperation, engineering, architecture, in-space physiology, material and life science experimentation, data communications, business, and management

    The self-reference effect on memory in early childhood

    Get PDF
    The self-reference effect in memory is the advantage for information encoded about self, relative to other people. The early development of this effect was explored here using a concrete encoding paradigm. Trials comprised presentation of a self- or other-image paired with a concrete object. In Study 1, 4- to 6-year-old children (N = 53) were asked in each trial whether the child pictured would like the object. Recognition memory showed an advantage for self-paired objects. Study 2 (N = 55) replicated this finding in source memory. In Study 3 (N = 56), participants simply indicated object location. Again, recognition and source memory showed an advantage for self-paired items. These findings are discussed with reference to mechanisms that ensure information of potential self-relevance is reliably encoded

    Management of broncholithiasis

    Get PDF
    Broncholithiasis is a condition in which calcified material has entered the tracheobronchial tree, at times causing airway obstruction and inflammation. Broncholiths generally originate as calcified material in mediastinal lymph nodes that subsequently erode into adjacent airways, often as a result of prior granulomatous infection. Disease manifestations range from asymptomatic stones in the airway to life-threatening complications, including massive hemoptysis and post-obstructive pneumonia. Radiographic imaging, particularly computed tomography scanning of the chest, is integral in the evaluation of suspected broncholithiasis and can be helpful to assess involvement of adjacent structures, including vasculature, prior to any planned intervention. Management strategies largely depend on the severity of disease. Observation is warranted in asymptomatic cases, while therapeutic bronchoscopy and surgical interventions may be necessary for cases involving complications. Bronchoscopic extraction is often feasible in cases in which the broncholith is freely mobile within the airway, whereas partially-embedded broncholiths represent additional challenges. Surgical intervention is indicated for advanced cases deemed not amenable to endoscopic management. Complex cases involving complications such as massive hemoptysis and/or bronchomediastinal fistula formation are best managed with a multidisciplinary approach, utilizing expertise from fields such as pulmonology, radiology, and thoracic surgery

    Positive action for HIV in schools in Kenya

    Get PDF
    The objective of this study was to test the feasibility of using comic books, role models, and edutainment to communicate HIV and AIDS messages to in-school young people in Kenya, with a view to improving their knowledge about the epidemic, enhancing communication about it, and promoting positive attitudes and behavior among them. The study was implemented by the Population Council in eight secondary schools in Nairobi, as part of the APHIA II Operations Research Project in collaboration with the AIDS Control Unit in the Ministry of Education, Well Told Story, and the National AIDS/STI Control Programme. The study found that there is need for HIV and AIDS and other sexual and reproductive health (SRH) information among students, and that using youth-friendly channels to communicate HIV and AIDS messages to in-school youth is acceptable to members of the school community. Furthermore, the use of such channels leads to improved knowledge of SRH issues, enhanced communication about SRH, and positive changes in attitudes and behavior of students

    Detecção de cepas de Actinobacillus actinomycetemcomitans de máxima e mínima leucotoxicidade em pacientes com doença periodontal

    Get PDF
    This study examined the prevalence of highly and minimally leukotoxic Actinobacillus actinomycetemcomitans in patients with periodontal disease. Pooled subgingival plaque samples from 136 patients with some form of periodontal disease were examined. Subjects were between 14 and 76 years of age. Clinical examinations included periodontal pocket depth (PD), plaque index (PI) and bleeding index (BI). The obtained plaque samples were examined for the presence of highly or minimally leukotoxic A. actinomycetemcomitans strains by the polymerase chain reaction (PCR). Chi-square and logistic regression were performed to evaluate the results. Forty-seven subjects were diagnosed with gingivitis, 70 with chronic periodontitis and 19 with aggressive periodontitis. According to chi-square there was no significant correlation detected between PD (chi2 = 0.73), PI (chi2 = 0.35), BI (chi2 = 0.09) and the presence of the highly leukotoxic A. actinomycetemcomitans. The highly leukotoxic A. actinomycetemcomitans strains were correlated with subjects that were 28 years of age and younger (chi2 = 7.41). There was a significant correlation between highly leukotoxic A. actinomycetemcomitans and aggressive periodontitis (chi2 = 22.06). This study of a Brazilian cohort confirms the strong association between highly leukotoxic A. actinomycetemcomitans strains and the presence of aggressive periodontitis.O presente estudo avaliou a prevalência de Actinobacillus actinomycetemcomitans de máxima e mínima leucotoxicidade em indivíduos com doença periodontal. Foram analisadas amostras de placa bacteriana subgengival de 136 indivíduos, entre 14 e 76 anos de idade, com algum tipo de doença periodontal. Os parâmetros clínicos avaliados incluíram profundidade de sondagem (PS), índice de placa bacteriana (IPB) e índice de sangramento gengival (ISG). A presença de amostras de A. actinomycetemcomitans de máxima e mínima leucotoxicidade foi avaliada por reação em cadeia da polimerase (PCR). Os resultados foram analisados empregando-se teste qui-quadrado e análise de regressão logística. Quarenta e sete indivíduos apresentaram gengivite, 70 indivíduos periodontite crônica e 19 indivíduos periodontite agressiva. O teste qui-quadrado não demonstrou correlação significativa entre PS (chi2 = 0,73), IPB (chi2 = 0,35), ISG (chi2 = 0,09) e a presença de amostras de máxima leucotoxicidade. A. actinomycetemcomitans de máxima leucotoxicidade apresentou associação com indivíduos com idade inferior a 28 anos (chi2 = 22,06). Os resultados observados nessa população brasileira confirmam a forte associação existente entre amostras de A. actinomycetemcomitans de máxima leucotoxicidade e periodontite agressiva

    Aflatoxin and the agriculture – nutrition nexus in Africa

    Get PDF
    Aflatoxins are a silent threat to health on the African continent. They are a group of mycotoxins – poisonous chemicals produced by fungi on crops that they colonise. Fatal in large amounts, in smaller concentrations aflatoxins harm humans, animals, birds and fish. The fungi that produce aflatoxins infect many of the cereals, legumes, oilseeds, roots, tubers, spices and nuts which are widely grown and eaten in Africa, placing aflatoxins at the very crux of the agriculture-nutrition nexus. This Technical Brief gives recommendations to fight against aflatoxins

    Understanding Barriers and Opportunities for Adoption of Conservation Practices on Rented Farmland in the US

    Get PDF
    Agricultural conservation programs often focus on farm operators when promoting conservation practices. However, much of U.S. farmland is owned by landowners not directly involved in farm operations. Rental arrangements on these lands can dis-incentivize the adoption of conservation practices that could improve soil health, water quality, and land values. To date, agricultural conservation policy has largely ignored the role of non-operating landowners (NOLs) and rental arrangements. We help improve the evidence-base for policy by identifying barriers to adoption of conservation practices on rented farmlands. Analysis of forty interviews with NOLs, operators, farm managers and university extension personnel in Iowa, Illinois, and Indiana revealed five categories of barriers: cash rent lease terms, rental market dynamics, information deficits/asymmetries, cognitive/interpersonal, and financial motivations. Some barriers, such as risk aversion and farm aesthetics were expressed by both NOLs and operators, while other barriers, such as status quo bias and annual renewal of leases were only expressed by NOLs and operators, respectively. To overcome barriers to conservation, interviewees recommended improving communication between NOLs and operators and modifying cash rent lease terms in order to build in flexibility for equitable sharing of risks and rewards. Agricultural conservation programs could readily apply these results—possibly working with intermediaries (e.g., farm managers, lawyers)—to offer communication and lease tools and assistance to NOLS and operators. Future research should evaluate the efficacy of these conservation interventions and how intermediaries affect the balance of power between NOLs and operators

    Evaluating the effectiveness of a combined approach to improve utilization of adolescent sexual reproductive health services in Kenya : a quasi-experimental design study protocol

    Get PDF
    Background: Access to and utilization of adolescent sexual and reproductive health (ASRH) services remains poor. ASRH services in Kenya are primarily offered in health facilities and include counselling, information, and services on family planning, sexually transmitted infections, and HIV and basic life skills. The Ministry of Education also provides age-appropriate sexual and reproductive health information in schools. This paper presents a study protocol that will evaluate the effectiveness of a combined approach toward improving utilization of ASRH services. Methods: This will be a quasi-experimental study utilizing qualitative and quantitative methods. During the formative phase, data will be collected through focus group discussions, in-depth interviews, and key informant interviews to explore the barriers and facilitators of provision and utilization of ASRH services. A quantitative design will be used to obtain baseline and endline data through household surveys and client exit interviews. Following the formative and baseline household and client exit assessments, an intervention focusing on provision of ASRH service package targeting boys and girls will be implemented for 18 months. The package will include contextualized ASRH services, including counselling and age-appropriate, comprehensive sexual education for behavior change with an aim to increase utilization of ASRH services. An analysis of the primary outcome (utilization of ASRH services) will be undertaken to establish the difference in difference between the control and intervention arm, before the intervention (using the baseline survey data) and after the intervention (using the endline survey data). Discussion: Adolescents have now been included in the World Health Organization's Global strategy for women's, children's and adolescents' health (2016-2030), acknowledging the unique health challenges facing young people and their pivotal role as drivers of change in the post-2015 era. This study will generate evidence on whether a combined school, facility, and community approach works toward improving utilization of ASRH services. The information generated from the study will be beneficial for programming as it will identify underlying reasons for low utilization of ASRH services. Results will help to shape ASRH programs and reduce teenage pregnancy within Kenya and other similar low middle-income countries
    • …
    corecore