132 research outputs found
Silicon micromachined waveguide components at 0.75 to 1.1 THz
Silicon micromachined waveguide components operating in the WM-250 (WR-1) waveguide band (0.75 to 1.1 THz) are measured. Through lines are used to characterize the waveguide loss with and without an oxide etch to reduce the surface roughness. A sidewall roughness of 100nm is achieved, enabling a waveguide loss of 0.2dB/mm. A 1THz band-pass filter is also measured to characterize the precision of fabrication process. A 1.8% shift in frequency is observed and can be accounted for by the 0.5deg etch angle and 2um expansion of the features by the oxide etch. The measured filter has a 13% 3dB bandwidth and 2.5dB insertion loss through the passband
Ciencia para Galápagos: una propuesta de estrategia y agenda de investigaciones prioritarias para la sustentabilidad del archipiélago
Breve reseña y detección de parásitos Leishmania en biopsias de piel de pacientes procedentes de Echeandía, provincia de Bolívar, Ecuador
Leishmaniasis is an important neglected tropical disease and the cause of significant morbidity in endemic countries such as Ecuador. It is transmitted by the bite of infected sand flies (Diptera Psychodidae) and has been reported from at least 22/24 provinces in the country including the foothills of the Andean mountains. Herein, we report the detection of Leishmania parasites, using PCR assays, in skin biopsies taken from ulcers of leishmaniasis patients from Echeandía in the province of Bolívar, Ecuador. These results suggest that most of the patients were infected with parasites from the braziliensis complex that among other species, includes Leishmania (Viannia) panamensis which is the most common species that causes cutaneous leishmaniasis in the Pacific coast, and Leishmania (V.) braziliensis, the cause of mucocutaneous lesions and significant patient disfiguration. More studies are needed to further identify the parasite species present in this area and address aspects of the parasite’s life cycle and transmission dynamics. Our preliminary results showed that the R174 and R798 18 S ribosomal DNA primers used in this study are effective to amplify Leishmania DNA and would be a useful tool to molecularly detect New World parasites causing tegumentary leishmaniasis.La leishmaniasis es una importante enfermedad tropical desatendida y es la causa de significativa morbilidad en países endémicos como el Ecuador La enfermedad es transmitida por la picadura de flebótomos (Diptera: Psychodidae) infectados y ha sido reportada en al menos 22/24 provincias del Ecuador incluyendo las estribaciones de la cordillera de los Andes. En esta publicación reportamos la detección de parásitos de Leishmania mediante ensayos de PCR en biopsias de piel de pacientes con diagnóstico de leishmaniasis provenientes de la zona de Echeandía en la Provincia de Bolívar, Ecuador Los resultados sugieren que la mayoría de los pacientes fueron infectados por parásitos pertenecientes al complejo braziliensis que incluye entre otras especies a Leishmania (Viannia) panamensis, el parásito más abundante en la costa Pacífica y causa de leishmaniasis cutánea y Leishmania (V.) braziliensis, la causa de lesiones mucocutáneas y significativa desfiguración del paciente. Más estudios son necesarios para identificar las especies del parásito que circulan en esta zona y abordar otros aspectos de los ciclos naturales de cada especie del parásito y la dinámica de transmisión. Los resultados preliminares muestran que los cebadores R174 and R798 del ADN 18 S ribosomal usados en este estudio son efectivos para amplificar ADN de Leishmania y pueden ser una herramienta útil en la detección de parásitos del Nuevo Mundo que causan leishmaniasis tegumentaria
Purchase decision and purchase delay of hedonic and utilitarian products in the face of time pressure and multiplicity of options
Purpose – Time pressure may change how people behave. The multiplicity of options and the nature of the products, hedonic or utilitarian, might increase the complexity of the choice and alter the effects of time pressure. Combining both factors, the purpose of this paper is to verify the moderating role played by the nature of the products observing the relationship between interaction (time pressure × multiplicity of options) and choice delay. Design/methodology/approach – A two-level factorial experimental design was applied (time pressure: with; without) × 2 (number of alternatives: two; six) × 2 (type of purchase: hedonic; utilitarian), with mixed design, considering the purchase delay a dependent variable. Findings – The results signal that the nature of the products moderates the effects of the interaction between time pressure and choice overload in purchase delay. Utilitarian purchases are more susceptible to the effects of time pressure and options overload than hedonic purchases. Originality/value – The interaction between time pressure and choice overload, researched in previous works, influences in different ways the purchase of utilitarian or hedonic products. This differentiation, taking into consideration the type of product, brings new perspectives on the purchase decision process and provides theoretical and practical information on the effects of information overload and time pressure over the consumer decision-making process
The Impact of Manuscript Learning vs. Video Learning on a Surgeon's Confidence in Performing a Difficult Procedure
Introduction: Operative surgical videos are a popular educational resource, not commonly a part of a peer-reviewed article. We wanted to evaluate the impact of either reading a peer-reviewed manuscript or watching an operative video on a surgeon's confidence in performing a complex case.Methods: Pediatric surgeons and fellows were asked to complete an initial questionnaire to assess their confidence (formulated as a score) in the diagnosis and operative repair of anal stenosis and rectal atresia.Results: Of 101 pediatric surgeons and fellows, 52 (51%) were randomized into a “manuscript” group and 49 (49%) into a “video” group. The mean confidence before the intervention was the same in the two groups (6.4 vs. 6.6). Attending surgeons started with more confidence than trainees (7.1 vs. 5.3, p < 0.001). In the manuscript group, the average confidence increased to 7.7 (p = 0.005), and in the video group the average confidence increased to 7.9 (p = 0.001) globally. Trainees in the video group significantly improved their confidence to a score of 6.6 (p = 0.035), as did attending surgeons to 8.5 (p = 0.01). In the manuscript group, only attendings significantly improved their confidence by 1.5–8.3 (p < 0.001), whereas trainees did not with a difference of 1.3 (p = 0.194). When considering experience level, physicians who reported never having performed this surgery improved only by reading the manuscript (3.9–6.2) (p = 0.004), not by watching the video (5.4–6.6) (p = 0.106). Surgeons with experience doing this operation (>5 times) did not improve their confidence by reading the manuscript (p = 0.10), nor by watching the video (p = 0.112).Conclusion: Reviewing either a detailed manuscript or operative video on the surgical management of rectal atresia and anal stenosis demonstrated a significant increase in self-reported confidence. Trainees benefitted the most from operative videos, whereas experienced surgeons did not improve their confidence by reading the manuscript nor watching the video
Hacia una visión compartida de Galápagos: el archipiélago como un sistema socioecológico
Entendiendo Galápagos como un sistema socioecológico complejo: implicaciones para la investigación científica en el archipiélago
Caracterização dos efeitos do veneno da taturana lonomia obliqua sobre a reatividade plaquetária
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Governor’s proclamation
This proclamation from Governor Mark Sanford proclaims June 22, 2004, as Bill Shaw Day
Guidelines for defining assembly batches of engineer-toorder concrete prefabricated systems
Os potenciais benefícios do uso de sistemas construtivos pré-fabricados do tipo engineer-to-order (ETO) abrangem desde a redução de custos e duração do empreendimento até melhorias na qualidade do produto. Entretanto, o escopo de sistemas de planejamento e controle da produção neste contexto deve ser diferente de empreendimentos tradicionais, pois existe a necessidade de coordenar diferentes tipos de fluxos (projeto, fabricação, operações logísticas e montagem). Neste contexto, é necessária a estabilização desses fluxos e consequente diminuição do trabalho em progresso, o que é relacionado ao esforço de reduzir o tamanho do lote de produção. O objetivo do presente trabalho é propor um conjunto de diretrizes para a definição dos lotes de montagem para sistemas pré-fabricados de concreto do tipo ETO com apoio de BIM 4D, com base em conceitos e princípios da produção enxuta. Design Science Research foi a abordagem metodológica adotada, tendo como base um estudo empírico em uma obra de ampliação de um aeroporto. As principais contribuições do trabalho são um conjunto de categorias de decisão para a definição dos lotes de montagem, e o desenvolvimento de ferramentas para apoiar a tomada de decisões.The potential benefits of engineer-to-order (ETO) prefabricated building systems include reductions in project cost and duration, and improvements in product quality. However, the scope of production planning and control systems in that context must be different from traditional projects, since it is necessary to coordinate different types of flows (design, manufacturing, logistics operations and site assembly). In this context, it is necessary to stabilise those flows and consequently reduce work in progress, which is strongly related to the effort of reducing production batch size. The aim of this research work is to propose a set of guidelines for the definition of assembly batches for ETO prefabricated concrete system, with the support of 4D BIM, based on concepts and principles of the lean production philosophy. Design Science Research was the methodological approach adopted in this investigation, which was based on an empirical study carried out in an airport expansion project. The main contributions of this study are a set of decision categories for the definition of assembly batches, and the development of tools for supporting decision-making in this context
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