Fracturas femorales en pacientes portadores de artroplastia de cadera

Se han revisado 25 pacientes con fractura femoral portadores de artroplatia de cadera. Las fracturas se clasifican según los tipos de Johansson. Se encontraron 9 tipo I, 9 tipo II y 7 tipo III. El tratamiento fue en 4 ocasiones conservador y en 21 quirúrgico: 2 osteosíntesis con tornillos de compresión, 9 recambios de vástago y 9 osteosíntesis con placa. Se valora el resultado del tratamiento de la fractura. Consolidaron todas salvo una tras el tratamiento inicial. El resultado de la artroplastia fue valorado según la Escala de Merle D'Aubigne siendo bueno en un 68% de los casos. Las complicaciones fueron 2 consolidaciones en varo, una infección superficial y una infección profunda. Se evalúan los diferentes tratamientos realizados y se expone nuestra actitud actual ante estas fracturas.The present study includes 25 patients with hip replacement who presented an ipsilateral fracture of the femur. According to Johansson's grading system, there were 9 types I fractures, 9 types II and 7 types III. Surgical treatment was indicated in 21 cases, and conservative treatment in 4. Of the 21 patients operated on 9, required stem replacement, 9 internal fixations with plate and screws, and inter-fragmentary compression screws in 2 cases. Outcome assessment showed that, except one case, all fractures healded after treatment. The results of the arthroplasty were good in 68% of cases according to the Merle D'Aubigne scale. Complications included 2 various deformities, one superficial infection and one deep infection

Sistema de cubicación con clasificación de productos para plantaciones de Populus x euramericana (Dode) Guinier cv. ‘I-214’ en la meseta norte y centro de España

A model is required to accurately estimate the merchantable volume of the poplar clone more widely used in Spain (Populus x euramericana cv. ‘I-214’). The present study was therefore carried out to obtain equations for predicting merchantable volume of this poplar clone. Data from 1,289 sampled trees collected in experimental plots, installed by INIA in central Spain, were available for analysis. The volume system fitted allows determining volume to a minimum diameter or height which establishes a merchantability threshold. Also two taper functions were derived to predict the diameter outside bark along the stem and the height at which that diameter occurs. A third-order continuous autoregressive error structure was used to account for autocorrelation. Weighted non linear regression was used to take into account the problem of heteroscedasticity observed in the volume equations. Comparison of the models was carried out using overall goodness-of-fit statistics (R2 and RMSE) and box plots of residuals against position or diameter classes.Es esencial para los inventarios y gestión forestal de las plantaciones del clon de chopo más empleado en España (Populus x euramericana cv. ‘I-214’), el disponer de ecuaciones que permitan la estimación de su volumen comercial. Para ello se han utilizado datos de 1.289 árboles procedentes de parcelas experimentales instaladas por el INIA en la meseta norte y centro de España. Las ecuaciones ajustadas permiten estimar el volumen hasta cualquier diámetro o altura límite de utilización y adicionalmente las funciones de perfil asociadas proporcionan los diámetros a lo largo del tronco y las alturas a las que estos aparecen. La autocorrelación en los residuos, debido a la naturaleza jerárquica de los datos, fue corregida en todas las ecuaciones mediante el empleo de un modelo continuo autorregresivo de orden tres. Por su parte, el problema de la heterocedasticidad, inherente a las ecuaciones de volumen, fue solventado mediante el empleo de regresión ponderada. La capacidad de ajuste global de los modelos fue analizada a través del coeficiente de determinación y de la raíz cuadrada del error medio cuadrático. También se llevó a cabo una evaluación de los modelos por clases de diámetros o alturas límites mediante diagramas «box-plots» o diagramas de caja

Retrieval of aerosol properties from zenith sky radiance measurements

This study explores the potential to retrieve aerosol properties with the GRASP algorithm (Generalized Retrieval of Atmosphere and Surface Properties) using as input measurements of zenith sky radiance (ZSR), which are sky radiance values measured in the zenith direction, recorded at four wavelengths by a ZEN-R52 radiometer. To this end, the ZSR measured at 440, 500, 675 and 870 nm by a ZEN-R52 (ZSRZEN), installed in Valladolid (Spain), is employed. This instrument is calibrated by intercomparing the signal of each channel with coincident ZSR values simulated (ZSRSIM) at the same wavelengths with a radiative transfer model (RTM). These simulations are carried out using the GRASP forward module as RTM and the aerosol information from a co-located CE318 photometer belonging to AERONET (AErosol RObotic NETwork) as input. The dark signal and the signal dependence on temperature are characterized and included in the calibration process. The uncertainties for each channel are quantified by an intercomparison with a co-located CE318 photometer, obtaining lower values for shorter wavelengths; they are between 3 % for 440 nm and 21 % for 870 nm. The proposed inversion strategy for the aerosol retrieval using the ZSRZEN measurements as input, i.e. so-called GRASP-ZEN, assumes the aerosol as an external mixture of five pre-calculated aerosol types. A sensitivity analysis is conducted using synthetic ZSRZEN measurements, pointing out that these measurements are sensitive to aerosol load and type. It also assesses that the retrieved aerosol optical depth (AOD) values in general overestimate the reference ones by 0.03, 0.02, 0.02 and 0.01 for 440, 500, 675 and 870 nm, respectively. The calibrated ZSRZEN measurements, recorded during 2.5 years at Valladolid, are inverted by the GRASP-ZEN strategy to retrieve some aerosol properties like AOD. The retrieved AOD shows a high correlation with respect to independent values obtained from a co-located AERONET CE318 photometer, with determination coefficients (r2) of 0.86, 0.85, 0.79 and 0.72 for 440, 500, 675 and 870 nm, respectively, and finding uncertainties between 0.02 and 0.03 with respect to the AERONET values. Finally, the retrieval of other aerosol properties, like aerosol volume concentration for total, fine and coarse modes (VCT, VCF and VCC, respectively), is also explored. The comparison against independent values from AERONET presents r2 values of 0.57, 0.56 and 0.66 and uncertainties of 0.009, 0.016 and 0.02 µm3 µm−2 for VCT, VCF and VCC, respectively.</p

Regional-scale stand density management diagrams for Pyrenean oak (Quercus pyrenaica Willd.) stands in north-west Spain

Stand Density Management Diagrams are useful tools for designing and evaluating alternative density management regimes without the need of implementing any silvicultural action, and allowing the future stand conditions to be predicted prior to implementing management schedules. In this study, stand density management diagrams were developed for Pyrenean oak (Quercus pyrenaica Willd.) stands in north-west Spain by including data on stand volume, stand aboveground biomass, stand stem biomass and carbon pools. Data were obtained from Third National Forest Inventory plots (n=1860). The large geographical area analyzed in this study was classified by provenance regions, which were compared in terms of biomass production in order to define areas with similar characteristics for use as management units. The comparisons identified 6 independent groups. Different stand-level models and the associated diagrams for the aforementioned stand variables were therefore developed for each group

Nutritional, carbon and energy evaluation of Eucalyptus nitens short rotation bioenergy plantations in northwestern Spain

This study provides essential information related to the nutrient and carbon levels and the energy potential of Eucalytpus nitens (Deane & Maiden) Maiden bionenergy plantations located in northwestern Spain. Nutritional analysis showed that leaves and bark had the highest concentrations of N, P, K and Mg. Carbon concentration was constant for all above-ground tree components. Nutrients and carbon were analyzed at stand level according to plantation productivity. Stemwood, the main tree component at the end of the rotation, had the highest nutrient content, except for N and Ca, which were highest in leaves and bark respectively. Based on this study, the nutrient content per ha of above-ground biomass was 243-706 kg N, 44-122 kg P, 131-375 kg K, 121-329 kg Ca and 25-67 kg Mg at the end of the bioenergy rotation (6-12 years, depending on site quality) and 19-56 Mg C ha-1. Energy analysis showed a fairly constant Net Calorific Value for wood, 18.32 ± 0.19 MJ kg-1. The results obtained are valuable for selecting the most appropriate forest management system in these bioenergy plantations, and thereby promote the sustainable use of woody crops

Use of stump diameter to estimate diameter at breast height and tree volume for major pine species in El Salto, Durango (Mexico)

Foresters may require to estimate the diameter at breast height (d.b.h.) and the volume of trees that have been cut, and may only have available the stumps as an indicator of the size of the trees. In the present study, equations for predicting both d.b.h.;volume from stump diameter inside bark were developed for major pine species in the forest region of El Salto, Durango (Mexico). The d.b.h. was estimated with relatively high accuracy with a simple linear model. The tree volume was also estimated with high precision by use of an allometric equation. Weighted linear and non-linear least squares methods were used to take into account the problem of heteroscedasticity observed in the volume-stump diameter relationships. The results of the non-linear extra sum of squares method and of the F tests indicated that species-based equations for estimating both d.b.h.;volume from stump diameter are required. © Institute of Chartered Foresters, 2007. All rights reserved

Dynamic growth model for I-214 poplar plantations in the northern and central plateaux in Spain

Information required by forest managers about homogeneous, even-aged, single-species stands can be provided by whole-stand models, which are easily built with data often available in forest inventories and which represent a good compromise between generality and accuracy. The objective of the present study was to develop a dynamic growth model for I-214 clonal poplar plantations in the northern and central plateaux in Spain by use of data obtained from a network of 198 experimental plots measured between 2 and 12 times. The overall model is a hierarchical system that consists of three main components a stand height projection function, a stand basal area projection function and a merchantable stand volume equation. In the model, the initial stand conditions at any point in time are defined by two state variables usually collected from common forest inventories stand mean height and stand basal area. The model includes two transition functions, derived by the generalized algebraic difference approach, to enable projection of these variables at any particular time. The projected variables were incorporated into a merchantable stand volume equation to enable calculation of the commercial stand volume at a minimum diameter, which establish a merchantability threshold. Sensitive analysis of the accuracy of the predictions of the submodels according to the length of the time interval was achieved by use of the critical error statistic and the RMSE in relative proportion of the mean. Results indicated that the overall model provides satisfactory predictions for time intervals of between 1 and 4 years

Using density management diagrams to assess crown fire potential in Pinus pinaster Ait. stands

International audienceContextDensity management diagrams (DMDs) are useful for designing, displaying and evaluating alternative density management regimes for a given stand-level management objective. The inclusion of variables related to crown fire potential within DMDs has not previously been considered.AimsThe aim of this study was to include isolines of variables related to crown fire initiation and spread in DMDs to enable identification of stand structures associated with different types of wildfire.MethodsBiometric and fuel data from maritime pine (Pinus pinaster Ait.) stands in NW Spain were used to construct DMDs. Different surface and crown fire behaviour models were used together to estimate crown fire potential.ResultsThe crown fire potential varied greatly throughout development of the maritime pine stands. Low stands were more prone to crowning. The type of crown fire was mainly determined by stand density.ConclusionThe DMDs developed can be used to identify relationships between stand structure and crown fire potential, thus enabling the design of thinning schedules aimed at reducing the likelihood of crowning