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Search Results: 1 - 10 of 71 matches for " RIVADENEIRA "
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Abordaje extremo lateral transcondilar para resecar un meningioma anterior del foramen magno
Campero,Alvaro; Rivadeneira,Conrado;
Revista argentina de neurocirug?-a , 2006,
Abstract: objective: to describe the far-lateral transcondylar approach performed to remove a meningioma of the anterior portion of the foramen magnum. description: a woman, 24-years old, with tetraparesis, greater in the right side, and paresis of the ix, x, and xi right cranial nerves, with a 9 months history. the mri showed a tumor in the anterior aspect of the foramen magnum (isointense in t1 and t2, with homogeneous enhance after gadolinium administration). intervention. in december 2005 the surgery was performed (far-lateral transcondylar approach), with complete removal of the lesion. histology: cordoid meningioma. the patient had a good outcome, with complete recovery of her neurological deficits. in the last control she was asymptomatic. conclusion. in this case, the far-lateral transcondylar was the most appropriate approach to completely resect a meningioma of the anterior portion of the foramen magnum.
Grados días acumulados en naranjas y mandarinas sobre pie trifolio en la zona de Concordia (Entre Ríos)
Rivadeneira, M.F.
Horticultura Argentina , 2012,
Abstract: Entre Ríos province is well known for its citrus fruit production; however there is a lack of information in the phenological description and quantification for the area of Concordia. The aim of this study was to quantify the degree-day accumulation from flowering to harvest for different oranges and mandarins varieties. The study was conducted during four consecutive growing seasons (2005/06 to 2008/09), and the phenological stages were registered every 2 weeks in Newhall, Lane Late, Valencia Late, and Salustiana oranges; Satsuma Okitsu and Clemenules mandarins, and Ellendale and Nova hybrids, all grafted on trifoliate orange rootstock. Degree days (DD) were calculated over a base temperature of 12.5 °C. The beginning of flowering changed significantly with the year (P = 0.0002) being earlier during the 2006/07 growing cycle and later during the year 2007/08. There were also significant differences in the DD accumulation between cultivars (P = 0.0001) and year (P = 0.0029). The earliest maturing Satsuma Okitsu and Clemenules mandarins reached 2,029.37 and 2,112.35 ± 57 DD accumulation, respectively, whereas Valencia Late orange had the highest value (2,526.35 ± 57) DD accumulation.------------------------------------------------------------------------------------------------------------ La provincia de Entre Ríos se caracteriza por su producción de naranjas y mandarinas, sin embargo existen pocos datos que indiquen los momentos y duración de las etapas fenológicas para el cultivo de los cítricos. El objetivo de este trabajo fue cuantificar los grados días desde floración a cosecha de variedades comerciales de naranjas y mandarinas en la zona de Concordia, Entre Ríos. Se registraron quincenalmente los estadios de la floración en variedades de naranja Newhall, Lane Late, Valencia Late y Salustiana (Citrus sinensis (L.) Osbeck), mandarina Satsuma Okitsu (C. unshiu Marc.), Clemenules (C. clementina Hort. ex Tan) y los híbridos Ellendale (C. sinensis L. Osbeck × C. reticulata Blanco) y Nova [C. clementina Hort. ex Tan, x (C. paradisi Macf. x C. tangerina Hort. ex Tan)] sobre pie trifolio (Poncirus trifoliata L. Raf.) durante cuatro campa as (2005/06 a 2009/10). Se calculó los grados días (GD) con temperatura base de 12,5 °C desde plena floración a cosecha. La fecha de inicio de floración fue variable de acuerdo al a o (P = 0,0002) siendo más temprana durante 2006/07 y más tardía en 2007/08. Se encontraron diferencias en los GD acumulados por variedad (P = 0,0001) y a o (P = 0,0029). Las mandarinas de maduración temprana Satsuma Okitsu y Clemenules fueron l
El Contrato de Reporte y su Regulacion en la Legislacion Peruana
Manuel Porro Rivadeneira
Revista e-Mercatoria , 2010,
Abstract: Actualmente uno de los problemas críticos que afrontan las empresas es el del financiamiento, ante este panorama existen dos opciones principales para las empresas: generar recursos propios e incrementar su capital social con recursos obtenidos de diversas fuentes de financiación externa.Justamente en este segundo escenario, surge la opcion que nos ocupa en el presente artículo. Pretendemos entonces dar una perspectiva general del Contrato de Reporte, sus características, sujetos intervinientes, obligaciones principales, con especial enfasis en su regulación en la regulación jurídica Peruana y una breve mención de la legislacion extranjera.
Responsabilidad social empresarial en el Perú
Manuel Porro Rivadeneira
Revista e-Mercatoria , 2008,
Abstract: Como parte del crecimiento y el desarrollo de los agentes económicos se ha creído conveniente analizar una institución de reciente data que afecta de modo especial a los grupos de interés (stakeholders) unidos a la empresa, es por ello que la presente investigación pretende analizar de modo amplio y general los aspectos más relevantes de la Responsabilidad Social Empresarial así como aquellos de difícil tratamiento y de modo específico resolveremos la pregunta cómo ha avanzado en materia de instrumentalización y normatividad la Responsabilidad Social Empresarial en el Perú?
Abordaje extremo lateral transcondilar para resecar un meningioma anterior del foramen magno
Alvaro Campero,Conrado Rivadeneira
Revista Argentina de Neurocirugía , 2006,
Abstract: Objetivo. Describir el abordaje extremo lateral transcondilar realizado para resecar un meningioma del sector anterior del foramen magno. Descripción. Mujer de 24 a os con una tetraparesia a predominio derecho y déficit de los nervios craneanos IX, X y XI del lado derecho, de 9 meses de evolución. La resonancia magnética mostró un proceso expansivo a nivel del sector anterior del foramen magno (isointenso en T1 y T2, captando en forma homogénea y bien marcada luego de la administración del gadolinio). Intervención. En diciembre de 2005 se realizó la cirugía (abordaje extremolateral transcondilar), con resección completa de la lesión. Anatomía patológica: meningioma cordoide. La paciente evolucionó mejorando completamente de su clínica neurológica, encontrándose actualmente sin ninguna secuela. Conclusión. En este caso el abordaje extremo lateral transcondilar fue la vía de elección para resecar completamente el meningioma del sector anterior del foramen magno. Objective: To describe the far-lateral transcondylar approach performed to remove a meningioma of the anterior portion of the foramen magnum. Description: A woman, 24-years old, with tetraparesis, greater in the right side, and paresis of the IX, X, and XI right cranial nerves, with a 9 months history. The MRI showed a tumor in the anterior aspect of the foramen magnum (isointense in T1 and T2, with homogeneous enhance after gadolinium administration). Intervention. In December 2005 the surgery was performed (far-lateral transcondylar approach), with complete removal of the lesion. Histology: cordoid meningioma. The patient had a good outcome, with complete recovery of her neurological deficits. In the last control she was asymptomatic. Conclusion. In this case, the far-lateral transcondylar was the most appropriate approach to completely resect a meningioma of the anterior portion of the foramen magnum.
Initial values for Riccati ODEs from variational PDEs
Costanza, Vicente;Rivadeneira, Pablo S.;
Computational & Applied Mathematics , 2011, DOI: 10.1590/S1807-03022011000200005
Abstract: the recently discovered variational pdes (partial differential equations) for finding missing boundary conditions in hamilton equations of optimal control are applied to the extended-space transformation of time-variant linear-quadratic regulator (lqr) problems. these problems become autonomous but with nonlinear dynamics and costs. the numerical solutions to the pdes are checked against the analytical solutions to the original lqr problem. this is the first validation of the pdes in the literature for a nonlinear context. it is also found that the initial value of the riccati matrix can be obtained from the spatial derivative of the hamiltonian flow, which satisfies the variational equation. this last result has practical implications when implementing two-degrees-of freedom control strategies for nonlinear systems with generalized costs.
Patrones asociados a la conducta de desplazamiento local en Phymactis clematis Drayton (Anthozoa: Actiniidae)
RIVADENEIRA,MARCELO M.; OLIVA,EDUARDO;
Revista chilena de historia natural , 2001, DOI: 10.4067/S0716-078X2001000400012
Abstract: phymactis clematis drayton is the most abundant and one of the largest species of sea anemone along the south american coast. likewise other sea anemone species, the adults of the p. clematis would have an active ability to make local movements. however, these have not been properly described, and causal factors are unknown. in this work we try to describe some of the basic patterns associated to the local movement behavior in p. clematis, assessed indirectly from the presence of bare rock halos around individuals in two rocky intertidal sites in the coast of northern chile (cavancha and colorado chico). movements were more frequent and had a higher intensity at colorado chico, where over 50 % of individuals showed movements, although they were mainly lower than 60 mm in length. at colorado chico, movements would occur in individuals larger than 40 mm of pedal diameter, whereas their intensity would decrease with body size. we discussed that causes of higher movement activity at colorado chico could be associated to the higher abundance and lower inter-individual spacing, which would produce physical interference among individuals. in this way, we suggested that the patterns associated to the individual's body size would arise secondarily, being dependent on the levels of local abundance. despite local movements of p. clematis at colorado chico occurred at a scale of a few centimeters, they could be affecting significantly the inter-individual spacing, increasing the average nearest neighbor distance. we argue that local movements could be an effective mechanism reducing the intraspecific competition in p. clematis
Cultura organizacional y la responsabilidad social en las universidades públicas
Pelekais,Cira de; Rivadeneira,Mariela;
Revista de Ciencias Sociales , 2008,
Abstract: the purpose of the study was to determine the relation between organizational culture and social responsibility in public universities on the c.o.l. the population consisted of directive, educational and administrative personal from public universities on the east coast of lake maracaibo, plus representatives from neighbors? associations. results showed that a directly proportional and moderate relationship exists between elements of the culture and social responsibility at the universities under study, a situation that explains the strong, positive relation. considering these findings, a series of strategic guidelines was suggested, directed toward four categories: functional, educational, cognitive, epistemological and social. conclusions were that some deficiencies exist in the presence of elements that constitute culture, such as beliefs, values, rituals, language and history, indicating that the perception the personnel holds is that of a slightly weak corporative culture.
Concentración de nutrientes en hojas de diferente estado de desarrollo en arándano
RIVADENEIRA, M. F.1
RIA : Revista de Investigaciones Agropecuarias , 2012,
Abstract: Es muy importante a la hora de realizar diagnóstico nutricional definir el momento y el órgano adecuado de muestreo para evitar posibles errores en la toma de decisiones. Existe poca información acerca de la composición mineral de las variedades presentes en las zonas productoras del cultivo de arándanos en Argentina.El objetivo de este trabajo consistió en determinar la concentración de nutrientes en hojas de dos edades en las variedades comerciales de arándano difundidas. El muestreo se realizó en 2008 en arándano southern highbush (Vaccinium corymbosum L. var Misty, Jewel y Emerald) en quintas comerciales ubicadas en Concordia, provincia de Entre Ríos, Argentina. Se recolectaron hojas totalmente expandidas, sin da os ni lesiones desde los 70 a 90 días después de plena floración (Plena flor: 15/08/2008) en dos edades de hoja (hoja con fruta formada el a o anterior y hoja sin fruta del a o en curso). Se realizaron las determinaciones de la concentración (g nutriente/100g MS) de N, P, K, Ca y Mg foliar. Los datos se sometieron a ANOVA, se tomó variedad y edad de hoja como factores fijos y concentración del nutriente como variable dependiente. La concentración de Mg dependió de la variedad, Misty presentó la mayor concentración de este nutriente con 0.30% Mg foliar, Emerald presentó 0.24 % y Jewel la menor concentración de 0.16 %Mg (p= 0.008). Hojas demayor edad presentaron mayor concentración de Mg (p=0.009). Es necesario considerar estas diferencias ala hora de realizar diagnósticos nutricionales.
Stapler access and visibility in the deep pelvis: A comparative human cadaver study between a computerized right angle linear cutter versus a curved cutting stapler
Toyooki Sonoda, Juan Verdeja, David E Rivadeneira
Annals of Surgical Innovation and Research , 2011, DOI: 10.1186/1750-1164-5-7
Abstract: Twelve male cadavers underwent pelvic dissection by 4 surgeons. After rectal mobilization as in a total mesorectal excision, the staplers were applied to the rectum as deep as possible in both the coronal and sagittal positions. The distance from the pelvic floor was measured for each application. A questionnaire rated the visibility and access of the stapling devices. Measurements were taken between pelvic landmarks to see what anatomic factors hinder the placement of a distal rectal stapler.The median (range) distance of the stapler from the pelvic floor in the coronal position for the RALC was 1.0 cm (0-4.0) vs. 2.0 cm (0-5.0) for the CC, p = 0.003. In the sagittal position, the median distance was 1.6 cm (0-3.5) for the RALC and 3.3 cm (0-5.0) for the CC, p < 0.0001. The RALC scored better than the CC in respect to: 1. interference by the symphysis pubis, 2. number of stapler readjustments, 3. ease of placement in the pelvis, 4. impediment of visibility, 5. ability to hold and retain tissue, 6. visibility rating, and 7. access in the pelvis. A shorter distance between the tip of the coccyx and the pubic symphysis correlated with a longer distance of the stapler from the pelvic floor (p = 0.002).The RALC is superior to the CC in terms of access, visibility, and ease of placement in the deep pelvis. This could provide important clinical benefit to both patient and surgeon during difficult rectal surgery.Oncologic outcomes after surgical treatment of rectal cancer have been improved by techniques such as the total mesorectal excision (TME) [1,2]. The division of the distal rectum with adequate tumor clearance is a critical step in a successful TME, and this is most commonly achieved using a stapling device. The ability to place a stapling device deep in the pelvis with good visualization could determine whether a sphincter-preserving operation is performed, or whether an abdominoperineal resection would be necessary. A distal resection margin of 2 cm has been gener
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