1000 resultados para 574.14


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Los pacientes con enfermedad renal crónica (ERC) terminal se caracterizan por presentar alteraciones nutricionales que se perpetúan independiente de la modalidad de la Terapia de Reemplazo Renal (TRR). En la diálisis peritoneal, tanto APD (automated peritoneal dialysis) como la CAPD (continuous ambulatory peritoneal dialysis) existe un alto riesgo de pérdida de albúmina por el filtrado peritoneal, sin diferencias claras en el estatus nutricional. El presente estudio caracteriza el estado nutricional de los pacientes incidentes en diálisis peritoneal de RTS Bogotá Regional 1, con un seguimiento de un año, para conocer los cambios en las variables nutricionales. Se realizó un estudio de cohortes retrospectivo, analizando 2 grupos según el tipo de diálisis peritoneal escogida (APD o CAPD), con un análisis análisis descriptivo trimestral de las características nutricionales y posteriormente una comparación entre las 2 modalidades de TRR. Encontrando un promedio de edad de 60,8 años, la mayoría hombres y etiología principal nefropatía diabética. La mayoría de las variables nutricionales permanecieron sin cambios durante seguimiento. El Test de equilibrio peritoneal para glucosa y creatinina mostró valores promedio bajo y promedio alto y la mayoría de pacientes un rango nutricional normal. Al comparar APD y CAPD, solo se encontraron de forma aislada, diferencias significativas en algunas variables aisladas. Este es el primer estudio en Colombia que evalúa diferentes aspectos nutricionales en diálisis peritoneal. Aunque con limitaciones metodológicas, es un punto de partida para la realización de estudios más robustos que del estado nutricional de los pacientes en diálisis peritoneal

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Detailed stable isotopic and calcium carbonate records (with a sampling resolution of 3000 yr.) from the middle Miocene section of hydraulic piston corer (HPC) Hole 574A provide a sequence that records the major shift in the oxygen isotopic composition of the world's oceans that occurred at about 14 Ma. The data suggest that this transition was rapid and spans about 30,000 yr. of sediment deposition. In intervals before and after the shift, the mean d18O values are characterized by a constant mean with a high degree of variability. The degree of variability in both the d18O and d13C records is comparable to that observed for the Pliocene and earliest Pleistocene and does not show a significant change before or after the major shift in the d18O record. Whereas the oxygen isotopic record is characterized by relatively stable mean values before and after the middle Miocene event, the d13C record shows a number of significant offsets in the mean value separated by intervals of high-frequency variations. Time and frequency domain analysis of all records from Hole 574A indicate that the frequency components shown to be related to orbital changes in the Pleistocene record are also present in the middle Miocene. The high variability observed in the Site 574 isotopic records places important constraints on models describing the role of formation of the Antarctic ice sheet during the middle Miocene climatic transitions. Thus, HPC Hole 574A provides a valuable sequence for detailed study of climatic variability during an important time in the Earth's history, although we cannot provide a definitive explanation of the major oxygen isotopic event of the middle Miocene.

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Detailed quantitative analyses of selected calcareous nannofossil species were used to determine the placement of zonal boundaries. In Hole 667A in the equatorial Atlantic Ocean, Zones CP19 through CN5 were recognized, whereas at Site 574 in the equatorial Pacific Ocean, only the CN4/CN5 boundary could be determined. Boundaries were identified by sharp rises and declines in abundance at the beginnings and ends, respectively, of index fossil ranges. The sharp rise in abundance at the beginning of the range of Triquetrorhabdulus rugosus provided a good datum level in both regions; the same is true for the sharp decline in abundance at the end of the range of Cyclicargolithus floridanus. The last occurrence of Helicosphaera ampliaperta was used to mark the CN3/CN4 boundary in Hole 667A, while at Site 574, H. ampliaperta was absent. The abundance pattern of Triquetrorhabdulus carinatus obtained from Hole 667A makes it impossible to observe a distinct disappearance level. Age/depth plots reveal uniform sedimentation rates at both sites during early Miocene times. At Site 667 in the Atlantic the mean sedimentation rate was 14.90 m/m.y., and at Site 574 in the Pacific it was 16.17 m/m.y. during this same period. One new nannofossil species, Triquetrorhabdulus rioensis, is described; and one species, Triquetrorhabdulus serratus, is recombined.