518 research outputs found

    Comprehensive testing of a defense systems communications satellite

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    The system level testing of the defense satellite communications system (DSCS) 3 program is reviewed. Concentration is on the results of the systems tests of the DSCS 3 development test model (DTM). The DSCS 3DTM consisted of engineering components interconnected in an open bench layout. The DTM tests were performed to demonstrate satellite electrical performance characteristics and to uncover design deficiencies and interface problems. The availability of the DTM test results prior to the fabrication of the flight model hardware permited the incorporation of necessary design changes with a minimum impact on program costs and schedules

    A Low Cost, Portable Fluorescence Correlation Spectrometer for Disease Diagnosis

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    People being treated for HIV need to periodically test to determine if their antiviral medication is effectively keeping their viral loads at a safe level. Individuals living in rural areas of developing countries would be more likely to get these viral load tests if an instrument existed which reduced costs and was small and rugged enough to be brought to the client rather than require the client to travel for hours to a clinic. The Diagnostics for Viral Disease team is developing such a device in cooperation with Dr. Edgar Simulundu and the Macha Research Trust in Zambia. Our design is based on advanced fluorescence spectroscopy utilizing a fluorescence protein probe, confocal optics, and low-cost, low-power electronics. This poster reviews work done in three subsystems of the overall instrument. First, we have optimized the program used during burst analysis spectroscopy for identification of individual viruses in dilute samples. Second, we have confirmed the operation of the amplifying and discriminating sections of the photon processing circuitry which converts light pulses into a digital signal ready to be processed in the signal analysis subsystem. Finally, we have completed the Field Programmable Gate Array (FPGA) and Raspberry Pi programming allowing successful transfer of the results of the signal processing in the FPGA to the Raspberry Pi for display to the end user. Going forward we will integrate these subsystems into a fully functional exploded prototype ready for the final stage of condensing the design into a portable prototype that can be tested and delivered to our client. Funding for this work provided by The Collaboratory for Strategic Partnerships and Applied Research.https://mosaic.messiah.edu/engr2022/1003/thumbnail.jp

    Associations for Citizen Science: Regional Knowledge, Global Collaboration

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    Since 2012, three organizations advancing the work of citizen science practitioners have arisen in different regions: The primarily US-based but globally open Citizen Science Association (CSA), the European Citizen Science Association (ECSA), and the Australian Citizen Science Association (ACSA). These associations are moving rapidly to establish themselves and to develop inter-association collaborations. We consider the factors driving this emergence and the significance of this trend for citizen science as a field of practice, as an area of scholarship, and for the culture of scientific research itself

    Effect of 3-Dimensional Virtual Reality Models for Surgical Planning of Robotic-Assisted Partial Nephrectomy on Surgical Outcomes: A Randomized Clinical Trial.

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    Importance: Planning complex operations such as robotic-assisted partial nephrectomy requires surgeons to review 2-dimensional computed tomography or magnetic resonance images to understand 3-dimensional (3-D), patient-specific anatomy. Objective: To determine surgical outcomes for robotic-assisted partial nephrectomy when surgeons reviewed 3-D virtual reality (VR) models during operative planning. Design, Setting, and Participants: A single-blind randomized clinical trial was performed. Ninety-two patients undergoing robotic-assisted partial nephrectomy performed by 1 of 11 surgeons at 6 large teaching hospitals were prospectively enrolled and randomized. Enrollment and data collection occurred from October 2017 through December 2018, and data analysis was performed from December 2018 through March 2019. Interventions: Patients were assigned to either a control group undergoing usual preoperative planning with computed tomography and/or magnetic resonance imaging only or an intervention group where imaging was supplemented with a 3-D VR model. This model was viewed on the surgeon\u27s smartphone in regular 3-D format and in VR using a VR headset. Main Outcomes and Measures: The primary outcome measure was operative time. It was hypothesized that the operations performed using the 3-D VR models would have shorter operative time than those performed without the models. Secondary outcomes included clamp time, estimated blood loss, and length of hospital stay. Results: Ninety-two patients (58 men [63%]) with a mean (SD) age of 60.9 (11.6) years were analyzed. The analysis included 48 patients randomized to the control group and 44 randomized to the intervention group. When controlling for case complexity and other covariates, patients whose surgical planning involved 3-D VR models showed differences in operative time (odds ratio [OR], 1.00; 95% CI, 0.37-2.70; estimated OR, 2.47), estimated blood loss (OR, 1.98; 95% CI, 1.04-3.78; estimated OR, 4.56), clamp time (OR, 1.60; 95% CI, 0.79-3.23; estimated OR, 11.22), and length of hospital stay (OR, 2.86; 95% CI, 1.59-5.14; estimated OR, 5.43). Estimated ORs were calculated using the parameter estimates from the generalized estimating equation model. Referent group values for each covariate and the corresponding nephrometry score were summed across the covariates and nephrometry score, and the sum was exponentiated to obtain the OR. A mean of the estimated OR weighted by sample size for each nephrometry score strata was then calculated. Conclusions and Relevance: This large, randomized clinical trial demonstrated that patients whose surgical planning involved 3-D VR models had reduced operative time, estimated blood loss, clamp time, and length of hospital stay. Trial Registration: ClinicalTrials.gov identifiers (1 registration per site): NCT03334344, NCT03421418, NCT03534206, NCT03542565, NCT03556943, and NCT03666104

    Prevalence of antimicrobial resistance and association with patient outcomes in a rural Kenyan hospital

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    Data on antimicrobial resistance (AMR) and association with outcomes in resource-variable intensive care units (ICU) are lacking. Data currently available are limited to large, urban centers. We attempted to understand this locally through a dual-purpose, retrospective study. Cohort A consisted of adult and pediatric patients who had blood, urine, or cerebrospinal fluid cultures obtained from 2016 to 2020. A total of 3,013 isolates were used to create the Kijabe Hospital’s first antibiogram. Gram-negative organisms were found to be less than 50% susceptible to third- and fourth-generation cephalosporins, 67% susceptible to piperacillin–tazobactam, 87% susceptible to amikacin, and 93% susceptible to meropenem. We then evaluated the association between AMR and clinical characteristics, management, and outcomes among ICU patients (Cohort B). Demographics, vital signs, laboratory results, management data, and outcomes were obtained. Antimicrobial resistance was defined as resistance to one or more antimicrobials. Seventy-six patients were admitted to the ICU with bacteremia during this time. Forty complete paper charts were found for review. Median age was 34 years (interquartile range, 9–51), 26 patients were male (65%), and 28 patients were older than 18 years (70%). Septic shock was the most common diagnosis (n = 22, 55%). Six patients had AMR bacteremia; Escherichia coli was most common (n = 3, 50%). There was not a difference in mortality between patients with AMR versus non-AMR infections (P = 0.54). This study found a prevalence of AMR. There was no association between AMR and outcomes among ICU patients. More studies are needed to understand the impact of AMR in resource-variable settings

    China’s emerging global role: dissatisfied responsible great power

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    China has (re)emerged as a great power in a world not of its own making. The distribution of power in major organisations and the dominant norms of international interactions are deemed to unfairly favour the existing Western powers, and at times obstruct China’s ability to meet national development goals. Nevertheless, engaging the global economy has been a key source of economic growth (thus helping to maintain regime stability), and establishing China’s credentials as a responsible global actor is seen as a means of ensuring continued access to what China needs. As an emerging great power that is also still in many respects a developing country, China’s challenge is to change the global order in ways that do not cause global instability or generate crises that would damage China’s own ability to generate economic growth and ensure political stability

    Paediatric and obstetric outcomes at a faith-based hospital during the 100-day public sector physician strike in Kenya

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    Published reviews of national physician strikes have shown a reduction in patient mortality. From 5 December 2016 until 14 March 2017, Kenyan physicians in the public sector went on strike leaving only private (not-for-profit and for-profit) hospitals able to offer physician care. We report on our experience at AIC-Kijabe Hospital, a not-for-profit, faith-based Kenyan hospital, before, during and after the 100-day strike was completed by examining patient admissions and deaths in the time periods before, during and after the strike. The volume of patients increased and exceeded the hospital's ability to respond to needs. There were substantial increases in sick newborn admissions during this time frame and an additional ward was opened to respond to this need. Increased need occurred across all services but staffing and space limited ability to respond to increased demand. There were increases in deaths during the strike period across the paediatric medical, newborn, paediatric surgical and obstetric units with an OR (95% CI) of death of 3.9 (95% CI 2.3 to 6.4), 4.1 (95% CI 2.4 to 7.1), 7.9 (95% CI 3.2 to 20) and 3.2 (95% CI 0.39 to 27), respectively. Increased mortality across paediatric and obstetrical services at AIC-Kijabe Hospital correlated with the crippling of healthcare delivery in the public sector during the national physicians' strike in Kenya

    Experimental Bounds on Masses and Fluxes of Nontopological Solitons

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    We have re-analyzed the results of various experiments which were not originally interested as searches for the Q-ball or the Fermi-ball. Based on these analyses, in addition to the available data on Q-balls, we obtained rather stringent bounds on flux, mass and typical energy scale of Q-balls as well as Fermi-balls. In case these nontopological solitons are the main component of the dark matter of the Galaxy, we found that only such solitons with very large quantum numbers are allowed. We also estimate how sensitive future experiments will be in the search for Q-balls and Fermi-balls.Comment: 19 pages, 7 eps figures, RevTeX, psfig.st

    Designing citizen science tools for learning: lessons learnt from the iterative development of nQuire

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    This paper reports on a 4-year research and development case study about the design of citizen science tools for inquiry learning. It details the process of iterative pedagogy-led design and evaluation of the nQuire toolkit, a set of web-based and mobile tools scaffolding the creation of online citizen science investigations. The design involved an expert review of inquiry learning and citizen science, combined with user experience studies involving more than 200 users. These have informed a concept that we have termed ‘citizen inquiry’, which engages members of the public alongside scientists in setting up, running, managing or contributing to citizen science projects with a main aim of learning about the scientific method through doing science by interaction with others. A design-based research (DBR) methodology was adopted for the iterative design and evaluation of citizen science tools. DBR was focused on the refinement of a central concept, ‘citizen inquiry’, by exploring how it can be instantiated in educational technologies and interventions. The empirical evaluation and iteration of technologies involved three design experiments with end users, user interviews, and insights from pedagogy and user experience experts. Evidence from the iterative development of nQuire led to the production of a set of interaction design principles that aim to guide the development of online, learning-centred, citizen science projects. Eight design guidelines are proposed: users as producers of knowledge, topics before tools, mobile affordances, scaffolds to the process of scientific inquiry, learning by doing as key message, being part of a community as key message, every visit brings a reward, and value users and their time

    Ipl1/aurora kinase suppresses S-CDK-driven spindle formation during prophase I to ensure chromosome integrity during meiosis

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    Cells coordinate spindle formation with DNA repair and morphological modifications to chromosomes prior to their segregation to prevent cell division with damaged chromosomes. Here we uncover a novel and unexpected role for Aurora kinase in preventing the formation of spindles by Clb5-CDK (S-CDK) during meiotic prophase I and when the DDR is active in budding yeast. This is critical since S-CDK is essential for replication during premeiotic S-phase as well as double-strand break induction that facilitates meiotic recombination and, ultimately, chromosome segregation. Furthermore, we find that depletion of Cdc5 polo kinase activity delays spindle formation in DDR-arrested cells and that ectopic expression of Cdc5 in prophase I enhances spindle formation, when Ipl1 is depleted. Our findings establish a new paradigm for Aurora kinase function in both negative and positive regulation of spindle dynamics
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