823 resultados para tidal current
Resumo:
The application vistas of superconductors have widened very much since the discovery of high TC superconductors (HTS) as many of the applications can be realised at 77 K rather than going down to 4.2 K, the liquid He temperature. One such application is the HTS current lead which is used to connect a superconducting system with a room temperature power source. Minimising heat leak to the cryogenic environment is the main advantage of introducing current leads into superconducting systems. The properties of HTSS likes zero resistance (avoiding joule heating) and very low thermal conductivity (minimized conductive heat transfer) make them ideal candidates to be used as current leads. There are two forms of HTS current leads. (i) bulk form (tube or rod) prepared either from YBCO or BSCCO and (ii) tape form prepared from Bi-2223 multifilamentary tapes. The tape form of current leads has many advantages with respect to the mechanical and thermal stability related criteria. Crucial information on various aspects of HTS current lead development are not available in the literature as those are kept proprietary by various companies around the world. The present work has been undertaken to tailor the properties of multifilamentary tapes for the current lead application and to optimise the processing parameters of the same for enhanced critical current density and field tolerance. Also it is the aim of the present investigation is to prepare prototype current leads engineered for operation in conduction cooled mode and test them for operational stability
Resumo:
Current Trends in Wireless Networking. DigitalLibrary@CUSAT. ...
Resumo:
The South West (S.W.) coast of India is blessed with a series of wetland systems popularly referred to as backwaters covering a total area of 46128.94 ha. These backwaters are internationally renowned for their aesthetic and scientific values including being a repository for several species fish and shell fishes. This is more significant in that three wetlands (Vembanad, Sasthamcotta and Ashtamudi) have recently been designated as Ramsar sites of international importance. Thirty major backwaters forming the crux of the coastal wetlands form an abode for over 200 resident or migratory fish and shellfish species. The fishing activities in these water bodies provide the livelihood to about 200,000 fishers and also provide full-time employment to over 50,000 fishermen. This paper describes the changes on the environmental and biodiversity status of selected wetlands, during 1994-2005 period. The pH was generally near neutral to alkaline in range. The salinity values indicated mixohaline condition ranging from 5.20-32.38 ppt. in the 12 wetlands. The productivity values were generally low in most of the wetlands during the study, where the gross production varied from 0.22 gC/m3/day in Kadinamkulam to 1.10 gC/m3/day in the Kayamkulam. The diversity of plankton and benthos was more during the pre-monsoon compared to the monsoon and post-monsoon periods in most of the wetlands. The diversity of plankton and benthos was more during the pre-monsoon compared to the monsoon and post-monsoon periods in most of the wetlands. The average fish yield per ha. varied from 246 kg. in Valapattanam to 2747.3 kg. in Azhikode wetland. Retting of coconut husk in most of the wetlands led to acidic pH conditions with anoxia resulting in the production of high amounts of sulphide, coupled with high carbon dioxide values leading to drastic reduction in the incidence and abundance of plankton, benthic fauna and the fishery resources. The major fish species recorded from the investigation were Etroplus suratensis, E. maculatus, Channa marulius, Labeo dussumieri, Puntius sp. Lutianus argentimaculatus, Mystus sp., Tachysurus sp. and Hemiramphus sp. The majority of these backwaters are highly stressed, especially during the pre monsoon period when the retting activity is at its peak. The study has clearly reflected that a more restrained and cautious approach is needed to manage and preserve the unique backwater ecosystems of South-west India
Resumo:
Heavy metals in the surface sediments of the two coastal ecosystems of Cochin, southwest India were assessed. The study intends to evaluate the degree of anthropogenic influence on heavy metal concentration in the sediments of the mangrove and adjacent estuarine stations using enrichment factor and geoaccumulation index. The inverse relationship of Cd and Zn with texture in the mangrove sediments suggested the anthropogenic enrichment of these metals in the mangrove systems. In the estuarine sediments, the absence of any significant correlation of the heavy metals with other sedimentary parameters and their strong interdependence revealed the possibility that the input is not through the natural weathering processes. The analysis of enrichment factor indicated a minor enrichment for Pb and Zn in mangrove sediments. While, extremely severe enrichment for Cd, moderate enrichment for Zn and minor enrichment of Pb were observed in estuarine system. The geo accumulation index exhibited very low values for all metals except Zn, indicating the sediments of the mangrove ecosystem are unpolluted to moderately polluted by anthropogenic activities. However, very strongly polluted condition for Cd and a moderately polluted condition for Zn were evident in estuarine sediments
Resumo:
In the eighties, John Aitchison (1986) developed a new methodological approach for the statistical analysis of compositional data. This new methodology was implemented in Basic routines grouped under the name CODA and later NEWCODA inMatlab (Aitchison, 1997). After that, several other authors have published extensions to this methodology: Marín-Fernández and others (2000), Barceló-Vidal and others (2001), Pawlowsky-Glahn and Egozcue (2001, 2002) and Egozcue and others (2003). (...)
Resumo:
Award winning student essay. This essay won the Student Writing Award Scheme via the HE Academy Subject Network for Information and Computer Sciences.
Resumo:
Evaluar si el Heliox reduce la resistencia en la vía aérea en niños y adolescentes con patología bronquial obstructiva que requieren ventilación mecánica. Materiales y Métodos: Estudio prospectivo observacional descriptivo en niños y adolescentes con patología bronquial obstructiva y ventilación mecánica con Fi02 ≤ 0,5. Medición de variables: resistencia, presión pico, presión media de la vía aérea, presión meseta, volumen corriente, autoPEEP, distensibilidad, PetCO2, ventilación de espacio muerto antes de inicio de heliox y a los 30 minutos, 2, 4, 6, 12, 18 y 24 horas y diariamente hasta suspenderlo por extubación o FiO2 > 0,5. Resultados: Resultados parciales, incluyó 9 pacientes encontrando descenso significativo de resistencia espiratoria a los 30 minutos (51,2 vs 32,3; p=0,0008 ), 2 horas ( 51,2 vs 33,4; p=0,0019) y 4 horas (51,2 vs 30,7; p=0,0012) así como de la resistencia inspiratoria a la hora 2 (48,6 vs 36,2; p = 0,013) y hora 4 (48,6 vs 30 ; p=0,004). Se observó tendencia al descenso de la PetCO2 que no fue significativa (52,3 vs 34,3: p=0,06). No se evidenció cambios en las variables; autoPEEP, presión pico, presión media de la vía aérea, distensibilidad, ventilación de espacio muerto, presión meseta y volumen corriente antes y después del inicio del Heliox. Conclusión: La ventilación mecánica con Heliox en niños con patología bronquial obstructiva parece ser que reduce de manera significativa la resistencia de la vía aérea, con tendencia al descenso de la PetC02. Se necesitan estudios prospectivos al menos observacionales analíticos que corroboren estos hallazgos.
Resumo:
Objetivo: Caracterizar a los pacientes que recibieron ventilación mecánica en las unidades de cuidado intensivo (UCI) de la Fundación Santa Fe de Bogotá entre los años 2009 y 2013. Metodología: Se analizó una cohorte retrospectiva de los pacientes en UCI que requirieron soporte ventilatorio mecánico al ingreso a la unidad independientemente de la causa. Resultados: La media de edad de los pacientes fue 63,83 años; el diagnóstico más frecuente de ingreso fue revascularización miocárdica, seguido por neumonía y recambio valvular aórtico; en el 43% de los casos la causa de la falla fue el estado postoperatorio. Los modos ventilatorios más frecuentemente utilizados fueron SIMV (27,5%) y ventilación asistida controlada (26,12%). El 50% de los pacientes fueron ventilados con PEEP < 6 cmH2O. La mortalidad bruta fue del 15%. 22% de los pacientes tuvieron estancia prolongada en UCI. Se aplicó protocolo de retiro de ventilación mecánica en el 77% de los pacientes. La duración de la ventilación mecánica es mayor a medida que aumenta la edad del paciente entre los 60 y los 80 años. La mortalidad es cercana al 50% alrededor de los 50 años y mayor a 80% después de los 80 años. El soporte ventilatorio por cinco o más días aumentó la mortalidad a 80% o más. Discusión y Conclusiones: Estos resultados son comparables a los encontrados en estudios previos. Este estudio puede ser considerado como el primer paso para generar un registro adecuado de la ventilación de la mecánica de las unidades de cuidado intensivo del país.
Resumo:
Aim: To review the current knowledge about suicide in cancer patients. Method: We searchedspecialized databases using keywords for articles published in the last two decades (1990-2010),and compiled and reviewed them in order to: indicate the prevalence of suicide in cancer patientsworldwide and in Colombia, differentiating the data by sex and age; establish the types of cancerthat are associated with suicide, identify risk factors for committing or considering suicide andpresent the strategies of professional and psychological intervention directed at cancer patientswith suicidal ideation and suicide attempts. The present article is a review of the information on thesubject. Results: We found that: in cancer patients, the suicide rate is two times higher thanin the general population; depression, suicidal ideation and location of cancer are some of therisk factors for suicide, and there is a lack of published guidelines for professional managementof the suicidal patient with cancer. Conclusion: The need to carry out research on the topic ofsuicide in cancer patients was established.
Resumo:
Purpose: there are many studies reporting the benefits of pulmonary rehabilitation, but few of them exhibit the behavior and activities of these services. This article presents the characteristics of services, parts management and training level of team members, in addition to the variables or instruments used to measure the effectiveness and impact in these programs. Method: it was made a cross sectional convenience sample which included seven pulmonary rehabilitation services in four Colombian cities (Bogotá, Medellín, Manizales and Cali), selected by the coverage, for having at least one year of experience and for being formally established and recognized nationwide. The interdisciplinary team of each service answered a survey that was validated through a pilot test and expert consensus. Participation was voluntary. Results: labor onset pulmonary rehabilitation services correspond to an average of a decade, with COPD and asthma pathologies of attention. The programs are characterized by an outpatient treatment with an average duration of eight to twelve weeks, with a frequency of an hour three times a week. Also, the director of the service is regularly a pulmonologist and the coordinator a physiotherapist (57.14%). The posgradual training of these professionals is notable, and they report to have procedural, administrative and communicative skills, but qualify regular there research skills. The physical and technological resources are well tested. 71.42% have done impact studies, but only 28.57% have been published. All have in common training in upper limbs, lower limbs, respiratory muscles, counseling, functional assessment and quality of life. The effectiveness and impact of programs is measured by the walking test, quality of life questionnaires and activities of daily living.
Resumo:
Delimitar el área de las dificultades del aprendizaje y conocer la panorámica actualizada de la investigación en esta área. El Current Index Journal Education (CIJE): todos los abstracts aparecidos bajo el epígrafe handicapped and gifted children, en el período 1980-1984, ambos inclusive. Estudio de la productividad de revistas. Impacto, vida media y ranking de las más productivas. Estudio de productividad de autores. Análisis de los autores más productivos. CIJE. Investigación bibliométrica: ley de Lotka, ley de dispersión de Bradford, índice de productividad total, índice de productividad fraccionaria, agrupamiento criterial de Crane. En cuanto a las revistas se codifican 81, con un total de 7287 artículos, siendo la media global de 90 artículos por revista. Una sola revista publica el 70 por ciento de la producción total. Con la ley de Bradford se hallan cuatro áreas de productividad: la primera área la forman cinco revistas que publican una media de 371'6 artículos. La segunda la forman 15 títulos con una media de 184'4 artículos, la tercera la forman 21 títulos con una media de 90 artículos. La cuarta la forman 40 títulos con una media de 42'2 artículos. Las revistas de las dos primeras áreas se publican todas en EEUU, excepto una. Para la jerarquización de autores se recurre al modelo de Crane: se encuentran 29 autores a los que incluir en grandes productores, 150 en el de productores moderados, 1220 aparecen como aspirantes y 5'190 como transeuntes. Los autores más productivos son: Frith, G., Kavale, K. A., Chandler, H. N., Torrance, E. Paul, Salend, S. J., Algozzine, B., Csapo, M., Forness, S., Stainback, W., Stainback, S., Ysseldike, J. Giordano, G. y Treffinger, D. Sería interesante realizar un estudio de las áreas temáticas.