116 research outputs found

    Статические нагрузки упругих зубьев зубчатых передач

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    Представим себе изготовленную из упругих материалов, статистически нагружен-ную зубчатую передачу, состоящую из двух зацепляющихся колес и обладающую не-точностями в нормальном шаге зацепления, характеризуемыми погрешностью α01 . В этом случае для соблюдения условий уравнения (1), сохранения постоянства угловых перемещений при вращении и обеспечения непрерывности зубьев, обладающих раз-личными размерами нормального шага зацепления, потребуется соответствующая сум-марная упругая деформация, вызванная передаваемым удельным крутящим моментом Mn1, будет эквивалентна величине углового перемещени

    Earth Through the Eyes of NAPA-1: Commissioning Results and the Next Steps in CubeSat Earth Observation

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    Disruptive CubeSat technology has brought scientific missions within reach that were previously only achievable through larger spacecraft. Satellite Earth Observation is now the new frontier for governments, private industry, and academia. With the recent launch of the Napa-1 satellite the Royal Thai Airforce (RTAF) has joined the ranks by having its first ever Earth Observation CubeSat in space. Its design, launch, early operations (LEOPS), and commissioning have been carried out by ISISpace, supporting the market’s need for imagery from space. Napa-1, meaning firmament in Thai, is a 6U CubeSat with the Gecko Imager from SCS Space as its primary payload, capable of taking RGB snapshot images with a 39-meter ground sampling distance (GSD) from 500 km altitude. In addition, the TriScape camera from Simera Sense flies onboard as an in-orbit technology demonstrator and is capable of delivering high-quality images with a GSD of 5 meter in the RGB bands. With well over 200 images taken by the primary payload this paper will look back on this exciting first period of Napa-1’s operational life and proudly present the very first images taken by the satellite and the lessons learnt throughout this turnkey mission. With that many images taken and that much data generated, the implemented onboard- and on ground data handling systems have been put to the test. ISISpace has made use of KUBOS’ Major Tom for command and control and having integrated a low-level processing tool, also for image data preview and delivery. Insight is provided into the systems and tools in place for image target planning, image acquisition, satellite command and control, and data delivery to the customer. How is it ensured targets are successfully captured? How is the usefulness of the image data efficiently validated? Subsequently, how is knowledge transfer to the customer accomplished to ensure successful routine operations? ISISpace will share the valuable lessons learnt from the mission planning, data handling, operations, and training points of view and show relevant in-orbit data on, for example, attitude behavior and temperature. In parallel, ISISpace has taken the next step in CubeSat Earth observation by using Napa-1 as a baseline while accommodating larger data streams and leveraging a higher level of automation. Together with the companies Simera Sense and Pinkmatter Solutions, multispectral images with automated on ground data processing (L0 up to L3) are to be delivered by the follow-up mission, Napa-2, to be launched in the summer of 2021. Details on this mission, including a further outlook at how CubeSat imagery and on ground processing will be shaped in the next few years will be provided

    Literary ethnography of evidence-based healthcare : accessing the emotions of rational-technical discourse

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    In this article I revisit the idea of literary ethnography (proposed by Van de Poel-Knottnerus and Knottnerus, 1994) as a method for investigating social phenomena constituted principally through literature. I report the use of this method to investigate the topic of evidence-based healthcare, EBHC. EBHC is a field of discourse much built upon a dichotomy between rationality and emotionality. In this context literary ethnography, a particular type of discourse analysis, is valuable for allowing researchers to bring the emotional currents of technical-rational discourse into conscious awareness. In such discourses, emotions are not written out by name. The researcher must discern emotional phenomena by experiencing the discourse, and (try to) bring them into intelligible expression. As I clarify this process I develop Van de Poel-Knottnerus and Knottnerus’ method theoretically, look to destabilise the rationalityemotionality dichotomy foundational to discourse around EBHC, and so transgress its conventional lines of thought.PostprintPeer reviewe

    Influences on uptake of reproductive health services in Nsangi community of Uganda and their implications for cervical cancer screening

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    <p>Abstract</p> <p>Background</p> <p>Cervical cancer is the most common female cancer in Uganda. Over 80% of women diagnosed or referred with cervical cancer in Mulago national referral and teaching hospital have advanced disease. Plans are underway for systematic screening programmes based on visual inspection, as Pap smear screening is not feasible for this low resource country. Effectiveness of population screening programmes requires high uptake and for cervical cancer, minimal loss to follow up. Uganda has poor indicators of reproductive health (RH) services uptake; 10% postnatal care attendance, 23% contraceptive prevalence, and 38% skilled attendance at delivery. For antenatal attendance, attendance to one visit is 90%, but less than 50% for completion of care, i.e. three or more visits.</p> <p>Methods</p> <p>We conducted a qualitative study using eight focus group discussions with a total of 82 participants (16 men, 46 women and 20 health workers). We aimed to better understand factors that influence usage of available reproductive health care services and how they would relate to cervical cancer screening, as well as identify feasible interventions to improve cervical cancer screening uptake.</p> <p>Results</p> <p>Barriers identified after framework analysis included ignorance about cervical cancer, cultural constructs/beliefs about the illness, economic factors, domestic gender power relations, alternative authoritative sources of reproductive health knowledge, and unfriendly health care services. We discuss how these findings may inform future planned screening programmes in the Ugandan context.</p> <p>Conclusion</p> <p>Knowledge about cervical cancer among Ugandan women is very low. For an effective cervical cancer-screening programme, awareness about cervical cancer needs to be increased. Health planners need to note the power of the various authoritative sources of reproductive health knowledge such as paternal aunts (<it>Sengas</it>) and involve them in the awareness campaign. Cultural and economic issues dictate the perceived reluctance by men to participate in women's reproductive health issues; men in this community are, however, potential willing partners if appropriately informed. Health planners should address the loss of confidence in current health care units, as well as consider use of other cervical cancer screening delivery systems such as mobile clinics/camps.</p

    Iron Status Predicts Treatment Failure and Mortality in Tuberculosis Patients: A Prospective Cohort Study from Dar es Salaam, Tanzania

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    Experimental data suggest a role for iron in the course of tuberculosis (TB) infection, but there is limited evidence on the potential effects of iron deficiency or iron overload on the progression of TB disease in humans. The aim of the present analysis was to examine the association of iron status with the risk of TB progression and death.\ud We analyzed plasma samples and data collected as part a randomized micronutrient supplementation trial (not including iron) among HIV-infected and HIV-uninfected TB patients in Dar es Salaam, Tanzania. We prospectively related baseline plasma ferritin concentrations from 705 subjects (362 HIV-infected and 343 HIV-uninfected) to the risk of treatment failure at one month after initiation, TB recurrence and death using binomial and Cox regression analyses. Overall, low (plasma ferritin<30 µg/L) and high (plasma ferritin>150 µg/L for women and>200 µg/L for men) iron status were seen in 9% and 48% of patients, respectively. Compared with normal levels, low plasma ferritin predicted an independent increased risk of treatment failure overall (adjusted RR = 1.95, 95% CI: 1.07 to 3.52) and of TB recurrence among HIV-infected patients (adjusted RR = 4.21, 95% CI: 1.22 to 14.55). High plasma ferritin, independent of C-reactive protein concentrations, was associated with an increased risk of overall mortality (adjusted RR = 3.02, 95% CI: 1.95 to 4.67). Both iron deficiency and overload exist in TB patients and may contribute to disease progression and poor clinical outcomes. Strategies to maintain normal iron status in TB patients could be helpful to reduce TB morbidity and mortality

    Mechanistic Insights into a Novel Exporter-Importer System of Mycobacterium tuberculosis Unravel Its Role in Trafficking of Iron

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    Elucidation of the basic mechanistic and biochemical principles underlying siderophore mediated iron uptake in mycobacteria is crucial for targeting this principal survival strategy vis-à-vis virulence determinants of the pathogen. Although, an understanding of siderophore biosynthesis is known, the mechanism of their secretion and uptake still remains elusive.Here, we demonstrate an interplay among three iron regulated Mycobacterium tuberculosis (M.tb) proteins, namely, Rv1348 (IrtA), Rv1349 (IrtB) and Rv2895c in export and import of M.tb siderophores across the membrane and the consequent iron uptake. IrtA, interestingly, has a fused N-terminal substrate binding domain (SBD), representing an atypical subset of ABC transporters, unlike IrtB that harbors only the permease and ATPase domain. SBD selectively binds to non-ferrated siderophores whereas Rv2895c exhibits relatively higher affinity towards ferrated siderophores. An interaction between the permease domain of IrtB and Rv2895c is evident from GST pull-down assay. In vitro liposome reconstitution experiments further demonstrate that IrtA is indeed a siderophore exporter and the two-component IrtB-Rv2895c system is an importer of ferrated siderophores. Knockout of msmeg_6554, the irtA homologue in Mycobacterium smegmatis, resulted in an impaired M.tb siderophore export that is restored upon complementation with M.tb irtA.Our data suggest the interplay of three proteins, namely IrtA, IrtB and Rv2895c in synergizing the balance of siderophores and thus iron inside the mycobacterial cell
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