Enabling interactive safety and performance trade-offs in early airframe systems design

Presented is a novel interactive framework for incorporating both safety and performance analyses in early systems architecture design, thus allowing the study of possible trade-offs. Traditionally, a systems architecture is first defined by the architects and then passed to experts, who manually create artefacts such as Fault Tree Analysis (FTA) for safety assessment, or computational workflows, for performance assessment. The downside of this manual approach is that if the architect modifies the systems architecture, most of the process needs to be repeated, which is tedious and time consuming. This limits the exploration of the design space, with the associated risk of missing better architectures. To overcome this limitation, the proposed framework automates parts of the safety and performance analysis in the context of the Requirement, Functional, Logical, and Physical (RFLP) systems engineering paradigm. Safety analysis is carried out by automatic creation of FTA models from the functional and logical flow views. Regarding performance analysis, computational workflows are first automatically created from the logical flow view, and then executed for a set of flight conditions over the range of the mission in order to determine the most demanding condition. Finally, performance characteristics of the subsystems, such as weights, power offtakes, ram drag etc. are evaluated at the most demanding flight condition, which enables the architect to compare architectures at aircraft level. The framework is illustrated with a representative example involving the design of an environmental control system of a civil aircraft, where the safety and performance trade-off is conducted for multiple ECS architectures

Clinical and epidemiological aspects of a hepatitis E outbreak in Bangui, Central African Republic

<p>Abstract</p> <p>Background</p> <p>Outbreaks of hepatitis E frequently occur in tropical developing countries during the rainy season due to overflowing drains, short-circuiting of networks of clean water and use of contaminated water from wells. Hepatitis E virus (HEV) infections are usually accompanied by general symptoms of acute liver disease. This study was conducted to define the clinical and epidemiological aspects of the HEV outbreak that occurred in May 2004 in Bangui.</p> <p>Methods</p> <p>Blood samples were collected from 411 patients aged 1-87 years, most of whom presented with jaundice, asthenia or signs of uncomplicated malaria, for a transversal study from June 2004 to September 2005. Patients were recruited at 11 health care centres, including two referral hospitals, after they had given informed consent. The diagnosis of HEV was made with a commercial ELISA test to detect IgM and/or IgG antibodies. HEV RNA was amplified by RT-PCR to confirm the presence of the viral genome.</p> <p>Results</p> <p>The most frequent clinical signs found were jaundice (93.4%), vomiting (50.7%), hepatalgia (47.4%), hepatomegaly (30.9%) and asthenia (26.8%), which are the general clinical signs of hepatic disease. Acute hepatitis E was found in 213 patients (51.8%) who were positive for HEV IgM antibodies. The IgG anti-HEV seroprevalence during this outbreak was high (79.5%). The age group 18-34 years was more frequently infected (91.2%) than those aged 1-17 (78.0%) or over 34 (64.9%) (p < 10^-6). RT-PCR performed on 127 sera from the 213 IgM-HEV-positive patients was amplified, and the presence of the viral genome was found in 65 samples.</p> <p>Conclusion</p> <p>Although no specific clinical signs exist for hepatitis E infection, people presenting with jaundice, vomiting, hepatalgia, asthenia, hepatomegaly or distended abdomen with no signs of uncomplicated malaria in tropical developing countries should be sent to a laboratory for testing for hepatitis E.</p

Effectiveness of Mechanisms and Models of Coordination between Organizations, Agencies and Bodies Providing or Financing Health Services in Humanitarian Crises: A Systematic Review.

BACKGROUND: Effective coordination between organizations, agencies and bodies providing or financing health services in humanitarian crises is required to ensure efficiency of services, avoid duplication, and improve equity. The objective of this review was to assess how, during and after humanitarian crises, different mechanisms and models of coordination between organizations, agencies and bodies providing or financing health services compare in terms of access to health services and health outcomes. METHODS: We registered a protocol for this review in PROSPERO International prospective register of systematic reviews under number PROSPERO2014:CRD42014009267. Eligible studies included randomized and nonrandomized designs, process evaluations and qualitative methods. We electronically searched Medline, PubMed, EMBASE, Cochrane Central Register of Controlled Trials, CINAHL, PsycINFO, and the WHO Global Health Library and websites of relevant organizations. We followed standard systematic review methodology for the selection, data abstraction, and risk of bias assessment. We assessed the quality of evidence using the GRADE approach. RESULTS: Of 14,309 identified citations from databases and organizations' websites, we identified four eligible studies. Two studies used mixed-methods, one used quantitative methods, and one used qualitative methods. The available evidence suggests that information coordination between bodies providing health services in humanitarian crises settings may be effective in improving health systems inputs. There is additional evidence suggesting that management/directive coordination such as the cluster model may improve health system inputs in addition to access to health services. None of the included studies assessed coordination through common representation and framework coordination. The evidence was judged to be of very low quality. CONCLUSION: This systematic review provides evidence of possible effectiveness of information coordination and management/directive coordination between organizations, agencies and bodies providing or financing health services in humanitarian crises. Our findings can inform the research agenda and highlight the need for improving conduct and reporting of research in this field

Incorporating safety in early (airframe) systems design and assessment

Presented is a novel framework for incorporating safety analysis in early systems architecture design.Traditionally, a systems architecture is first defined by the architects and then passed to safety experts, who manually create artefacts such as Function Hazard Analysis (FHA) or Fault Tree Analysis (FTA) for safety assessment. The problem with this manual approach is that if the architect modifies the systems architecture, then the whole safety assessment process needs to be repeated, which is tedious and time consuming. To overcome this limitation, the proposed framework automates the creation of safety models such as FHA and FTA by utilizing the Requirement, Functional, Logical, and Physical (RFLP) systems engineering paradigm. The framework supports three main activities. First, the safety targets are determined by performing a FHA of the architecture and the Requirements view is updated. Second, compliance with the safety requirements is analyzed using dynamic fault trees, automatically generated from the Logical view. Interactive visualization techniques are proposed to interpret the safety results, e.g. highlighting the greatest contributors to the probability of failure. Third, an algorithm is developed that enables the designer to interactively improve the architecture’s safety by introducing more reliable components or increasing redundancy. The concept is illustrated with a representative example, where the environmental control system of a civil aircraft is studied from a safety point of view

Combined Airframe and Subsystems Evolvability Exploration During Conceptual Design

Evolvable designs allow development costs of future products to be lowered significantly. This work contributes to aircraft conceptual design space exploration by enabling simultaneous combined exploration of both airframe and subsystem evolvability. This is made possible by combining existing subsystems-architecting and design space exploration techniques with novel commonality assessment algorithms. The proposed techniques are demonstrated via a simple single-aisle passenger aircraft evolvability study

Evaluation de la sensibilité à Bemisia tabaci (Gen) de 13 variétés de tomate (Lycopersicon esculentum Mill.) et expression des symptômes de la jaunisse en cuillère des feuilles (TYLCV) en Côte d\'Ivoire

L\'étude a été conduite,de janvier à juin 2003, au Centre de la Côte d\'Ivoire. Elle a eu pour but d\'évaluer au champ, le comportement de 13 variétés de tomate contre la pression de Bemisia tabaci (Gen), une mouche vecteur du virus de la jaunisse en cuillère des feuilles de tomate («Tomato yellow leaf curl virus» : TYLCV). Le niveau d\'infestation des variétés par les populations de mouches blanches (oeufs, larves, et adultes) a été évalué par comptage. Les symptômes du TYLCV et les rendements ont été déterminés pour chaque variété de tomate à la recolte. Les résultats montrent que les formes mobiles et les formes fixes du vecteur ont été plus fréquentes autour du 57e jour après repiquage. Les taux les plus importants des oeufs et des larves de l\'insecte ont été observés sur les faces inférieures des folioles basales des plantes pendant la même période. Des variétés en provenance d\'Israël (HAZERA) et de Taiwan (AVRDC), se sont révélées très productives malgré la présence d\'une importante population de mouches blanches.This study was carried out, from January to June 2003, in the Central part of Côte d\'Ivoire. The objective was to make an on-farm evaluation of the reaction of 13 tomatoe varieties faced with Bemisia tabaci (Gen), a white fly responsible for yellow leaf curl virus (TYLCV). Infestation of the varieties by the white flies (eggs, larvae, and adults) was evaluated by counting. Diseases symptoms and tomatoe productivity were determined for each variety at the end of the experiment. Results show that mobile adults and fixed forms (larvae, eggs) of the vector were more predominant around 57 days after planting. The most important quantities of eggs and larvae were observed on the lower faces of the basal leaves of the plants during the same period. Some varieties from Israel (HAZERA) and Taiwan (AVRDC) proved to be highly productive despite important populations of white flies. Keywords: Bemisia tabaci, virus de la jaunisse en cuillère, variétés de tomate.Agronomie Africaine Vol. 19 (3) 2007: pp. 241-24