24 research outputs found

    Dynamics and Control of a Stop Rotor Unmanned Aerial Vehicle

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    The objective of this work was to develop a variety of control systems for a Stop-Rotor Unmanned Aerial Vehicle (UAV) in hover flight. The Stop-Rotor UAV has capabilities of Vertical Take-off and Landing (VTOL) like a helicopter and can convert from a helicopter mode to an airplane mode in mid-flight. Thus, this UAV can hover as a helicopter and achieve high mission range of an airplane. The stop-rotor concept implies that in mid-flight the thrust generating helicopter rotor stops and rotates the blades into airplane wings. The thrust in airplane mode is then provided by a pusher propeller. The aircraft configuration presents unique challenges in flight dynamics, modeling and control. In this paper a mathematical model is derived, and then the model is simulated with non-zero initial conditions. Various control systems are then implemented. The control techniques utilized are a linear control, optimal linear control and a nonlinear control with the objective of stabilizing the UAV in hover flight. Settling time and control effort are then compared across the different control systems.DOI:http://dx.doi.org/10.11591/ijece.v2i5.158

    Guided Navigation Control of an Unmanned Ground Vehicle using Global Positioning Systems and Inertial Navigation Systems

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    This paper demonstrates the use of Global Positioning System (GPS) and Inertial Navigation System (INS) in order to develop an Unmanned Ground Vehicle (UGV) devised to perform a wide variety of outdoor tasks. There are many applications for autonomous UGVs such as tactical and surveillance applications, exploration of areas inaccessible by humans. Capable to navigate to a specific location, and control their motion depending on their surroundings without human intervention. The inertial navigation system makes use of Inertial Measurement Units (IMUs) to measure the change to the UGV's positional parameters, orientation and speed which are continuously monitored and updated. With the advent of GPS, and the positional data from the inertial system the positional information is computed leading to a more accurate control of the UGV; which otherwise suffers from integration drift that occurs with the implementation of inertial systems alone. Autonomous control of the UGV is implemented by coupling GPS sensor and Mission Planner, a tool to map waypoints from Google Maps. Furthermore, system stability and ideal PID (Proportional, Integral and Derivative) values are determined using bicycle modeling analysis to achieve better estimates and control of the UGV.DOI:http://dx.doi.org/10.11591/ijece.v4i3.518

    Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

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    BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

    Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

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    Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

    Spatiotemporal Characteristics of the Largest HIV-1 CRF02_AG Outbreak in Spain: Evidence for Onward Transmissions

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    Background and Aim: The circulating recombinant form 02_AG (CRF02_AG) is the predominant clade among the human immunodeficiency virus type-1 (HIV-1) non-Bs with a prevalence of 5.97% (95% Confidence Interval-CI: 5.41–6.57%) across Spain. Our aim was to estimate the levels of regional clustering for CRF02_AG and the spatiotemporal characteristics of the largest CRF02_AG subepidemic in Spain.Methods: We studied 396 CRF02_AG sequences obtained from HIV-1 diagnosed patients during 2000–2014 from 10 autonomous communities of Spain. Phylogenetic analysis was performed on the 391 CRF02_AG sequences along with all globally sampled CRF02_AG sequences (N = 3,302) as references. Phylodynamic and phylogeographic analysis was performed to the largest CRF02_AG monophyletic cluster by a Bayesian method in BEAST v1.8.0 and by reconstructing ancestral states using the criterion of parsimony in Mesquite v3.4, respectively.Results: The HIV-1 CRF02_AG prevalence differed across Spanish autonomous communities we sampled from (p &lt; 0.001). Phylogenetic analysis revealed that 52.7% of the CRF02_AG sequences formed 56 monophyletic clusters, with a range of 2–79 sequences. The CRF02_AG regional dispersal differed across Spain (p = 0.003), as suggested by monophyletic clustering. For the largest monophyletic cluster (subepidemic) (N = 79), 49.4% of the clustered sequences originated from Madrid, while most sequences (51.9%) had been obtained from men having sex with men (MSM). Molecular clock analysis suggested that the origin (tMRCA) of the CRF02_AG subepidemic was in 2002 (median estimate; 95% Highest Posterior Density-HPD interval: 1999–2004). Additionally, we found significant clustering within the CRF02_AG subepidemic according to the ethnic origin.Conclusion: CRF02_AG has been introduced as a result of multiple introductions in Spain, following regional dispersal in several cases. We showed that CRF02_AG transmissions were mostly due to regional dispersal in Spain. The hot-spot for the largest CRF02_AG regional subepidemic in Spain was in Madrid associated with MSM transmission risk group. The existence of subepidemics suggest that several spillovers occurred from Madrid to other areas. CRF02_AG sequences from Hispanics were clustered in a separate subclade suggesting no linkage between the local and Hispanic subepidemics

    Relevance of the basophil high-affinity IgE receptor in chronic urticaria: clinical experience from a tertiary care institutio

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    BACKGROUND: The high-affinity IgE receptor (FcεRI) expression on effector cells has been poorly characterized in patients with chronic urticaria (CU) to date. OBJECTIVES: To investigate the FcεRI expression on blood basophils in a large cohort of patients with CU and its potential relationship with relevant features of the disease. METHODS: Basophil FcεRI expression was measured by flow cytometry in 287 patients with CU (192 with chronic spontaneous urticaria and 95 with chronic inducible urticaria) at their initial evaluation in our department. A control group of healthy nonatopic individuals was included to provide reference data, and the effect of antihistamine and anti-IgE therapy on the basophil FcεRI expression was also evaluated in a cohort of patients with CU. RESULTS: The median FcεRI expression was found significantly higher in patients with CU compared with healthy controls (P < .0001). A positive correlation was found between serum IgE levels and basophil FcεRI expression (R = 0.422; P < .001). Significantly higher FcεRI levels on basophils were detected in patients with CU who presented with concomitant atopic features (P = .003), negative autologous serum skin test (P = .002), negative autologous plasma skin test (P = .009), or undetected levels of antithyroid antibodies (P = 0.01). Baseline FcεRI expression was not related to the activity and duration of the disease, and was not significantly modified during antihistamine therapy; however, it correlated with the clinical response to omalizumab (P = .003). CONCLUSIONS: Although further multicenter studies are needed to corroborate these findings, the assessment of basophil FcεRI levels might be relevant in daily clinical practice supporting an autoimmune pathogenesis and predicting response to anti-IgE treatment

    Paracoccidioidomicosis Diagnóstico por el laboratorio de 333 casos

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    Paracoccidioidomycosis is the most important systemic mycosis in our country, as demonstrated by the high frequency of diagnosed cases. In this report, 333 paracoccidioidomycosis cases diagnosed at the four laboratories of the Pulmonary Mycoses Program of the Instituto Nacional de Salud and at the Mycology Laboratory of the same institute during a twelve year period are presented. In relation to the age and sex distribution, 316 patients (95%) were male, and 17 (5%) female (male:female ratio 18.5:l) and 55.5% of the patients were in the age group 41-60. Regarding the clinical presentation, the chronic adult form was the predominant one (99%) with unifocal presentation in 50.7% of the cases. The ample geographic distribution of the disease demonstrates the importance of the diagnostic centers. The sensitivities of 97% for immunodiffusion and 90% for complement fixation validate them as important diagnostic tests.La frecuencia con la que se diagnostica la paracoccidioidomicosis en nuestro país sigue apoyando la consideración de que esta entidad constituye la micosis sistémica más importante en nuestro medio. En el presente trabajo se informan 333 casos de pacientes con paracoccidioidomicosis, diagnosticados por los cuatro laboratorios del programa de micosis pulmonares del lnstituto Nacional de Salud y por el laboratorio de micología médica del Grupo de Microbiología del mismo instituto, durante un período de 12 años (1981-1992). El diagnóstico fue establecido con la sospecha clínica y una combinación de pruebas de laboratorio con diferentes sensibilidades y especificidades. De los 333 pacientes estudiados, 31 6 (95%) eran hombres y 17 (5%) mujeres; relación hombre:mujer 18,5:1. El 55,5% de los pacientes se encontraba en el grupo de edad de 41 a 60 años. La forma clínica predominante fue la forma crónica del adulto (99%) con 50,7% de presentación unifocal. La distribución geográfica fue muy amplia y señaló la importancia de los centros de diagnóstico. Las sensibilidades del 97% para la inmunodifusión y del 90% para la fijación del complemento confirmaron su importante valor diagnóstico
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