97 research outputs found

    Influencia de la fertilización en el crecimiento de radicchio "Rosso di Chioggia" cultivado en dos ambientes diferentes

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    Este trabajo evalúa la influencia de la fertilización en radicchio tipo "Rosso de Chioggia" (precocidad media) sobre algunos índices de crecimiento. Se realizaron ensayos durante dos campañas en Rovigo (Italia) y una en Mendoza (Argentina), aplicándose dosis crecientes de NPK, identificadas como N0P0K0, N1P1K1, N2P2K2, en Mendoza y en Rovigo, además, N3P2K2. Durante el cultivo se calcularon índices de crecimiento como: relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR), specific leaf area (SLA), leaf weigh ratio (LWR), crop growth ratio (CGR), leaf area index (LAI) and leaf area duration (LAD). En Mendoza, el CGR estuvo fuertemente influenciado por NAR desde el trasplante hasta alcanzar 776 grados días (GDD); desde 1052 a 1653 GDD el CGR fue afectado por el LAI el cual aumentó marcadamente debido a las condiciones ambientales favorables. Entre los 1052 y 1653 GDD el incremento del LAI determinó una reducción en la eficiencia fotosintética. En Rovigo, la tendencia de los índices fue disímil en los dos años, encontrándose respuestas diferentes en LAR y en SLA. En el segundo año, el CGR siempre arrojó valores más altos, mientras que NAR no difirió en ninguno de los años. En la segunda mitad del ciclo, CGR estuvo fuertemente asociado a una menor eficiencia fotosintética, debido a la formación de la cabeza. Valores elevados de LAI indicaron una extensión del ciclo, retrasando la formación de la cabeza. Las plantas alcanzaron la madurez comercial con LWR entre 0,35 - 0,40 g g-1. En ambos ambientes, no se observó claramente el efecto de la fertilización sobre los índices; si bien las dosis más altas mostraron mayor actividad de crecimiento en las etapas tempranas.This study evaluated the influence of fertilization on some growth indexes in radicchio "Rosso di Chioggia". The trial was conducted in Rovigo (Italy) for two years and in Mendoza (Argentina) for one year. Increasing doses of macronutrients were considered, identified as N0P0K0, N1P1K1, N2P2K2 and, only in Rovigo, N3P2K2. Some indexes related to growth analysis: relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR), specific leaf area (SLA), leaf weigh ratio (LWR), crop growth ratio (CGR), leaf area index (LAI) and leaf area duration (LAD) were calculated during the growing cycle. At Mendoza CGR was strongly influenced by NAR from transplant until 776 growth degree days (GDD). After that moment, CGR was affected by LAI that increased markedly due to favourable environmental conditions. From 1052 to 1653 GDD the high increase of LAI determined a reduction in photosynthetic efficiency. At Rovigo the trends in index values showed differences between the two years considered, especially in LAR and SLA. In the second year CGR had always higher values; mainly due to higher LAI values, since NAR did not differ significantly during the years. In the second half of the growing cycle, CGR was instead strongly linked to a contraction of photosynthetic effectiveness, due to head formation. High LAI values showed a growing cycle extension to the detriment of early head formation. It was also observed that when LWR is around 0.35 - 0.40 g g-1, the plant reaches marketable maturation and is ready to be harvested. In both environments, no clear effects of fertilization were observed on the growth indexes. In any case highly fertilized plants showed higher growing activity especially at the beginning of the growing cycle.Fil: Filippini, María Flavia. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Ingeniería AgrícolaFil: Nicoletto, Carlo. Università degli Studi di Padova (Italia). Dipartimento Territorio e Sistemi Agro-ForestaliFil: Sambo, Paolo. Università degli Studi di Padova (Italia). Dipartimento Territorio e Sistemi Agro-ForestaliFil: Cavagnaro, Juan Bruno. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Ciencias BiológicasFil: Pimpini, Ferdinando. Università degli Studi di Padova (Italia). Dipartimento Territorio e Sistemi Agro-Forestal

    Unexplained falls are frequent in patients with fall-related injury admitted to Orthopaedic wards: the UFO Study (Unexplained Falls in Older patients)

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    To evaluate the incidence of unexplained falls in elderly patients affected by fall-related fractures admitted to orthopaedic wards, we recruited 246 consecutive patients older than 65 (mean age 82 \ub1 7 years, range 65-101). Falls were defined "accidental" (fall explained by a definite accidental cause), "medical" (fall caused directly by a specific medical disease), "dementia-related" (fall in patients affected by moderate-severe dementia), and "unexplained" (nonaccidental falls, not related to a clear medical or drug-induced cause or with no apparent cause). According to the anamnestic features of the event, older patients had a lower tendency to remember the fall. Patients with accidental fall remember more often the event. Unexplained falls were frequent in both groups of age. Accidental falls were more frequent in younger patients, while dementia-related falls were more common in the older ones. Patients with unexplained falls showed a higher number of depressive symptoms. In a multivariate analysis a higher GDS and syncopal spells were independent predictors of unexplained falls. In conclusion, more than one third of all falls in patients hospitalized in orthopaedic wards were unexplained, particularly in patients with depressive symptoms and syncopal spells. The identification of fall causes must be evaluated in older patients with a fall-related injury

    Assessment of the potential risk for humans exposed to millimeter-wave wireless LANs: the power absorbed in the eye

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    This paper deals with the interaction between a millimeter-wavelength plane wave and the human eye. The study has been conducted utilizing the finite difference time domain (FDTD) numerical technique, and an accurate eye model obtained through photographic images of the human head. A partly automatic procedure has been developed to obtain the FDTD-compatible eye model. The dielectric properties of the human tissues at millimeter wavelengths have been extrapolated from experimental data available at lower frequencies and by using Debye’s dispersion equation. The power distribution in the exposed eye has been calculated in both conditions of closed and open eye, and the results have been compared with the limits settled by some of the most recognized safety standards for human exposure

    Evaluation of the SAR distribution in the human head for cellular phones used in a partially closed environment

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    The purpose of this paper is to calculate the specific absorption rate (SAR) distribution in a human head exposed to the electromagnetic field emitted from a handheld cellular phone operating in the 900 MHz range in a partially closed environment. The environment could be, for example, the interior of a car, a condition of exposure which is largely diffused nowadays. The presence of reflecting surfaces near the phone modifies the current distribution on, and the emitting properties of, the phone antenna. Therefore, the distribution of the absorbed power inside the head is different from that absorbed in the free space exposure condition. The finite-difference time-domain (FDTD) method has been used to evaluate the SAR in a realistic anatomically based model of the human head for different antenna-handset configurations and for different antenna-head distances. The environmental effects have been simulated through partially or totally reflecting walls located in various positions with reference to the phone. It is found that the presence of a horizontal reflecting wall over the head decreases the SAR values in the part of the head directly exposed to the phone antenna, while it increases the SAR values in the part not directly exposed. On the contrary, the presence of a vertical wall, located in proximity of the phone and parallel to it, raises the SAR values everywhere into the hea
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