14 research outputs found

    Advanced Aerobots for Scientific Exploration

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    The Picosat and Uninhabited Aerial Vehicle Systems Engineering (PAUSE) project is developing balloon-borne instrumentation systems as aerobots for scientific exploration of remote planets and for diverse terrestrial purposes that can include scientific exploration, mapping, and military surveillance. The underlying concept of balloon-borne gondolas housing outer-space-qualified scientific instruments and associated data-processing and radio-communication equipment is not new. Instead, the novelty lies in numerous design details that, taken together, make a PAUSE aerobot smaller, less expensive, and less massive, relative to prior aerobots developed for similar purposes: Whereas the gondola (including the instrumentation system housed in it) of a typical prior aerobot has a mass of hundreds of kilograms, the mass of the gondola (with instrumentation system) of a PAUSE aerobot is a few kilograms

    FIMCAR III: Car-to-Car Test Results

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    The assessment of compatibility in frontal impacts has to address the importance of different vehicle structures. A critical component in the assessment is to identify, quantitatively, what constitutes good performing structures. In particular, the concepts of structural alignment and structural interaction need to be investigated. Structural alignment is incorporated in the FIMCAR candidate compatibility assessments to achieve geometric alignment of identifiable crashworthiness structures. Structural interaction is also a global assessment of how structures interact with a collision partner during the crash. The performance of lower vehicle structures in a crash has been identified as important as they may not be evaluated in a structural alignment assessment, but can contribute to structural interaction and thereby improve collision outcome. There has been, however, no clear definition of the characteristics for lower load paths that improve vehicle safety and how these structures manifest themselves in proposed test procedures. FIMCAR has developed a vehicle crash test program that investigates the performance of vehicle structures using three different test series. The first test series used Super mini vehicles with different front end architectures. These tests with, and without, geometric alignment allowed the effectiveness of a lower load path to be compared to a case without a lower load path. A second set of tests investigated the importance of lower load paths for SUV type vehicles where the main front structures may not align with the main structures in a collision partner, but a lower load path may offset the consequences of this initial misalignment. A final test series investigated how the lower load paths in higher SUV type vehicles influence safety in side impact conditions and thus identify potential side effects of a new assessment procedure. Results of the test program show that the presence of a lower load path contributes to a more robust performance of the vehicle. The rearward offset of a lower load path could be reviewed and used to quantify when a lower structure design can contribute to structural interaction in both frontal and side impact configurations

    Health & Demographic Surveillance System Profile: The Taabo Health and Demographic Surveillance System, CĂ´te d'Ivoire

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    The Taabo Health and Demographic Surveillance System (HDSS) is located in south-central CĂ´te d'Ivoire, approximately 150 km north-west of Abidjan. The Taabo HDSS started surveillance activities in early 2009 and the man-made Lake Taabo is a key eco-epidemiological feature. Since inception, there has been a strong interest in research and integrated control of water-associated diseases such as schistosomiasis and malaria. The Taabo HDSS has generated setting-specific evidence on the impact of targeted interventions against malaria, schistosomiasis and other neglected tropical diseases. The Taabo HDSS consists of a small town, 13 villages and over 100 hamlets. At the end of 2013, a total population of 42 480 inhabitants drawn from 6707 households was under surveillance. Verbal autopsies have been conducted to determine causes of death. Repeated cross-sectional epidemiological surveys on approximately 5-7% of the population and specific, layered-on haematological, parasitological and questionnaire surveys have been conducted. The Taabo HDSS provides a database for surveys, facilitates interdisciplinary research, as well as surveillance, and provides a platform for the evaluation of health interventions. Requests to collaborate and to access data are welcome and should be addressed to the secretariat of the Centre Suisse de Recherches Scientifiques en CĂ´te d'Ivoire: [[email protected]

    The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

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    INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

    Automated Design Synthesis of Structures using Growth Enhanced Evolution

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    Engineering design is a complex problem on generating and evaluating a variety of options. In traditional methods, this typically involves evaluating up to a dozen different point designs. The limit on the process is the amount of time to generate, refine, and evaluate the various concepts. Using a computer helps to speed up the process, but human involvement still remains the weakest link. The natural extension of this process is to continually and rapid generate, refine, and evaluate concepts entirely automatically. Evolutionary Algorithms provide such a method, by emulating natural evolution. The computer maintains a population point design, each of which is represented by a gene string that is allowed to change (mutate) and combine with other genes (crossover). At each generation, every individual is modified then evaluated and the improved solutions proceed to the next generation. This thesis will extend the biological model by introducing a growth process to each individual. This is akin to the concept of a multi-cellular organism developing in the womb. An encoding for discrete truss structures is described that provides for such an extension. The truss grows from a few basic elements. After showing several examples demonstrating the growth process, the method is applied to a couple simple examples using evolutionary algorithms.</p

    SIM Lite: Ground Alignment of the Instrument.

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    We present the start of the ground alignment plan for the SIM Lite Instrument. We outline the integration and alignment of the individual benches on which all the optics are mounted, and then the alignment of the benches to form the Science and Guide interferometers. The Instrument has a guide interferometer with only a 40 arc-seconds field of regard, and 200 arc-seconds of alignment adjustability. This requires each sides of the interferometer to be aligned to a fraction of that, while at the same time be orthogonal to the baseline defined by the External Metrology Truss. The baselines of the Science and Guide interferometers must also be aligned to be parallel. The start of these alignment plans is captured in a SysML 1 Instrument System model, in the form of activity diagrams. These activity diagrams are then related to the hardware design and requirements. We finish with future plans for the alignment and integration activities and requirements. 1
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