949 resultados para transmission clusters


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ABSTRACT INTRODUCTION: Emergent and re-emergent waterborne protozoans have become a worldwide public health problem, especially among vulnerable groups. METHODS: This cross-sectional study evaluated 17 HIV-infected children and their families. RESULTS: A high (76.5%) percentage of parasite-infected children was observed, even among children with CD4+ T-cell counts of >200 cells/mm3. Giardia spp., Cryptosporidium spp. and Cyclospora spp. were observed in 41.2% of these children Low income, poor hygiene practices, and co-infection in domestic, peridomestic and scholastic environments were significant sources of these intestinal infections. CONCLUSIONS: Early diagnosis, timely treatment, and socio-educational interventions may improve the health conditions of this vulnerable population.

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Abstract: INTRODUCTION Characterization of Mycobacterium tuberculosis (MTB) isolates by DNA fingerprinting has contributed to tuberculosis (TB) control. The aim of this study was to determine the genetic diversity of MTB isolates from Tehran province in Iran. METHODS MTB isolates from 60 Iranian and 10 Afghan TB patients were fingerprinted by standard IS6110-restriction fragment length polymorphism (RFLP) analysis and spoligotyping. RESULTS The copy number of IS6110 ranged from 10-24 per isolate. The isolates were classified into 22 clusters showing ≥ 80% similarity by RFLP analysis. Fourteen multidrug-resistant (MDR) isolates were grouped into 4 IS6110-RFLP clusters, with 10 isolates [71% (95% CI: 45-89%)] in 1 cluster, suggesting a possible epidemiological linkage. Eighteen Iranian isolates showed ≥ 80% similarity with Afghan isolates. There were no strains with identical fingerprints. Spoligotyping of 70 isolates produced 23 distinct patterns. Sixty (85.7%) isolates were grouped into 13 clusters, while the remaining 10 isolates (14.2%) were not clustered. Ural (formerly Haarlem4) (n = 22, 31.4%) was the most common family followed by Central Asian strain (CAS) (n = 18, 25.7%) and T (n = 9, 12.8%) families. Only 1strain was characterized as having the Beijing genotype. Among 60 Iranian and 10 Afghan MTB isolates, 25% (95% CI: 16-37) and 70% (95% CI: 39-89) were categorized as Ural lineage, respectively. CONCLUSIONS A higher prevalence of Ural family MTB isolates among Afghan patients than among Iranian patients suggests the possible transmission of this lineage following the immigration of Afghans to Iran.

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Abstract: Cryptosporidiosis is a very prominent disease in the field of public health, and usually causes diarrhea. We describe two immunocompetent patients who presented with chronic diarrhea that was ultimately found to be caused by continuous exposure to well water contaminated with the microbial cysts (oocysts) of the Cryptosporidium spp parasite. We describe the patients' histories and possible explanations for their prolonged symptoms.

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Poliomyelitis associated with live strain vaccine is defined as the paralytic form of the acute anterior poliomyelitis related to the vaccine strain. Since these strains behave similarly to the wild-type virus, we can differentiate, epidemiologically, two types of vaccine-associated poliomyelitis: cases in which the patient was vaccinated and cases in which the patient had had contact with vaccinated individuals. We herein present the case of an unvaccinated child, with a clinical picture of an acute anterior poliomyelitis associated with the live strain vaccine, whose brother received the Sabin vaccine 20 days before the onset of the symptoms. Vaccine strain of the type 3 poliovirus was isolated in fecal culture and a presented mutation in nucleotide 472 (C®U) in the 5' non-coding region, which is strongly related to the higher strain virulence.

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Mansonella ozzardi is transmitted by two dipterian families, Ceratopogonidae (midges) and Simuliidae (black flies). In Brazil, black flies are vectors for this filariasis until now. In this paper, we determined the seasonality, parity capacity and parasitic infection rate of Cerqueirellum argentiscutum. The work was carried out in the Porto Japão community, Lower Solimões River, Amazonas, Brazil. Results show that the black flies were more abundant during the rainy season (from December to May). The number of parous flies was higher in every sampling during the course of year. Monthly Biting Rate (MBR1 123742.00, MBR2 86701.50) was high, although Parasitic Infection Rate (PIR1 0.06, PIR2 0.08) and Annual Transmission Potential (ATP 7.25) were low in numbers.

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Wireless body sensor networks (WBSNs) constitute a key technology for closing the loop between patients and healthcare providers, as WBSNs provide sensing ability, as well as mobility and portability, essential characteristics for wide acceptance of wireless healthcare technology. However, one important and difficult aspect of WBSNs is to provide data transmissions with quality of service, among other factors due to the antennas being small size and placed close to the body. Such transmissions cannot be fully provided without the assumption of a MAC protocol that solves the problems of the medium sharing. A vast number of MAC protocols conceived for wireless networks are based on random or scheduled schemes. This paper studies firstly the suitability of two MAC protocols, one using CSMA and the other TDMA, to transmit directly to the base station the signals collected continuously from multiple sensor nodes placed on the human body. Tests in a real scenario show that the beaconed TDMA MAC protocol presents an average packet loss ratio lower than CSMA. However, the average packet loss ratio is above 1.0 %. To improve this performance, which is of vital importance in areas such as e-health and ambient assisted living, a hybrid TDMA/CSMA scheme is proposed and tested in a real scenario with two WBSNs and four sensor nodes per WBSN. An average packet loss ratio lower than 0.2 % was obtained with the hybrid scheme. To achieve this significant improvement, the hybrid scheme uses a lightweight algorithm to control dynamically the start of the superframes. Scalability and traffic rate variation tests show that this strategy allows approximately ten WBSNs operating simultaneously without significant performance degradation.

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A new integrated mathematical model for the simulation of an offshore wind system having a rectifier input voltage malfunction at one phase is presented in this paper. The mathematical model considers an offshore variable-speed wind turbine on a floating platform, equipped with a permanent magnet synchronous generator using full-power three-level converter to inject energy into the electric network, through a high voltage direct current transmission submarine cable. The model for the drive train is a discrete three mass, incorporating the dynamic of the moving surface. A case study is presented to access conclusion about the malfunction.

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The aim of this study was to determine if mycobacterial lineages affect infection risk, clustering, and disease progression among Mycobacterium tuberculosis cases in The Netherlands. Multivariate negative binomial regression models adjusted for patient-related factors and stratified by patient ethnicity were used to determine the association between phylogenetic lineages and infectivity (mean number of positive contacts around each patient) and clustering (as defined by number of secondary cases within 2 years after diagnosis of an index case sharing the same fingerprint) indices. An estimate of progression to disease by each risk factor was calculated as a bootstrapped risk ratio of the clustering index by the infectivity index. Compared to the Euro-American reference, Mycobacterium africanum showed significantly lower infectivity and clustering indices in the foreign-born population, while Mycobacterium bovis showed significantly lower infectivity and clustering indices in the native population. Significantly lower infectivity was also observed for the East African Indian lineage in the foreign-born population. Smear positivity was a significant risk factor for increased infectivity and increased clustering. Estimates of progression to disease were significantly associated with age, sputum-smear status, and behavioral risk factors, such as alcohol and intravenous drug abuse, but not with phylogenetic lineages. In conclusion, we found evidence of a bacteriological factor influencing indicators of a strain's transmissibility, namely, a decreased ability to infect and a lower clustering index in ancient phylogenetic lineages compared to their modern counterparts. Confirmation of these findings via follow-up studies using tuberculin skin test conversion data should have important implications on M. tuberculosis control efforts.

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The concepts involved in sustainable textile fashion, demanding good knowledge about raw materials, processes, end use properties and circuits amongst others, are able to determine the way the textile product is designed and the behavior of the consumer, regarding life style and buying decisions. The textile product`s life integrates raw materials, their processing, distribution, use by the consumer and destination of the product after useful lifetime, this is, his complete life cycle. It is very important to recognize the power of the consumer to influence parameters related to sustainability, namely when he decides how, when and why he buys and afterwards by the attitudes taken during and after use. The conscious act of consumption involves ethical, ecological and technical knowledge in which the concern is overall lifecycle of the fashion product and not exclusively aesthetic and symbolic values strongly related with its ephemeral nature. The present work proposes the classification of textile products by means of an innovative label aiming to establish a rating related to the Life of Fashion Products, by using parameters considered with especial impact in lifecycle, as textile fibers, processing conditions, generated wastes, commercialization circuits, durability and cleaning procedures. This label for sustainable fashion products aims to assist the stakeholders with informed attitudes and correct decisions in order to promote the objectives of sustainable fashion near designers, consumers and industrial experts.

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El presente proyecto plantea utilizar integralmente la técnica de Resonancia Magnética Nuclear en sólidos como un medio experimental que permite entender fenómenos de la física fundamental, como así también realizar aplicaciones de interés en el campo de la química, los desarrollos farmacéuticos y la biología. Novedosas técnicas experimentales serán empleadas, en conjunción con otras más tradicionales, en la caracterización de nuevas estructuras poliméricas acomplejadas a metales, membranas biológicas y compuestos de interés farmacéutico en vías de desarrollo, los cuales presentan el fenómeno de polimorfismo . Esto se llevará a cabo complementando los resultados de RMN en sólidos con técnicas tanto espectroscópicas como analíticas (Infrarrojo, Difracción de Rayos X, Calorimetría, RMN en solución) y trabajo interdisciplinario. Paralelamente al desarrollo de estos temas, profundizaremos mediante investigación básica, en la compresión de la dinámica cuántica y el surgimiento de la irreversibilidad en sistemas de espines nucleares. Observaremos en particular la generación, evolución y control de las coherencias cuánticas múltiples en sistemas cuánticos abiertos, lo cual nos da información sobre tamaño de clusters de espines. Esto permitirá la correcta implementación de secuencias de pulsos sofisticadas, como así también desarrollar nuevos métodos de medición aplicados a la caracterización estructural y a la dinámica molecular de sólidos complejos. Debemos resaltar que este proyecto está conectado con aspectos tanto básicos como aplicados de la RMN en sólidos como técnica experimental, la cual se desarrolla en el país únicamente en FaMAF-UNC. Se nutre además de trabajo multidisciplinario promoviendo la colaboración con investigadores y becarios de distintas áreas (física, química, farmacia, biología) provenientes de distintos puntos del país. Finalmente podemos afirmar que este plan impulsa la aplicación de la física básica proyectada a diferentes áreas del conocimiento, en el ámbito de la provincia de Córdoba. The aim of the present proyect is to use Nuclear Magnetic Resonance (NMR) as a complete techique that allows the understanding of fundamental physics phenomena and, at the same time, it leads to important applications in the fields of chemistry, pharmaceutical developments and biology. New experiments will be used together with traditional ones, in the characterization of new metal-polymer complexes, biological membranes and pharmaceutical compounds, some of them presenting polymorfism. NMR experiments will be complemented with diverse spectroscopic and analytical techniques: Infrared, X ray Diffraction, Thermal Analysis, solution NMR, as well as multidisciplinary investigation. Additionally, the present proyect plans to study in depth several aspects of quantum dynamics phenomena and decoherence in nuclear spin systems. The present proyect is connected with basic and applied aspects of the solid state NMR technique, developed in our country, only at FaMAF-UNC. It is is composed by multidisciplinary work and it promotes the collaboration with researchers and students coming from different fields (physics, chemistry, pharmaceutical developments, biology) and different points of our country.

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Transmission-line supertheory, generalized transmission-line theory, radiation

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Magdeburg, Univ., Fak. für Elektrotechnik und Informationstechnik, Diss., 2011

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This paper devotes to evaluation of performance bottlenecks and algorithm deficiencies in the area of contemporary reliable multicast networking. Hereby, the impact of packet delay jitter on the end-to-end performance of multicast IP data transport is investigated. A series of tests with two most significant open-source implementations of reliable multicast is performed and analyzed. These are: UDP-based File Transfer Protocol (UFTP) and NACK-oriented Reliable multicast (NORM). Tests were targeted to simulate scenario of content distribution in WAN – sized Content Delivery Networks (CDN). Then, results were grouped and averaged, by round trip time and packet losses. This enabled us to see jitter influence independently on round trip time(RTT) and packet loss rates. Revealed jitter influence for different network conditions. Confirmed, that appearance of even small jitter causes significant data rate reduction.