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Objetivo: Determinar los T-score de un densitómetro periférico de calcáneo para obtener una especificidad del 90% en el diagnóstico de osteoporosis y densidad mineral ósea (DMO) normal. Material y métodos: Se realizaron densitometrías por absorciometría dual de rayos X (DXA) en calcáneo (PIXI-LUNAR) y central (HOLOGIC) a 693 mujeres remitidas para estudio de osteoporosis. Se calculó mediante curvas ROC (receiver operator characteristic curve) la sensibilidad y especificidad de los distintos T-scores del densitómetro periférico para el diagnóstico de osteoporosis y normalidad. Resultados: La edad media era de 58,2 ± 9,6 años (30 y 93 años). Los T-score del PIXI para detectar osteoporosis y normalidad con una especificidad del 90% fueron -1,3 y + 0,6 respectivamente. Conclusión: Un T-score inferior a -1,3 o superior a +0,6 a nivel del calcáneo indican alta probabilidad de osteoporosis y normalidad respectivamente. Sólo debería realizarse densitometría central cuando la DMO periférica se encontrase entre estos valores.Proyecto financiado por la Generalitat Valenciana – Conselleria de Sanitat – DOGV 5337 – 1.09.2007 – Resolución 20.10.2007

Biochar application to soil has the potential to affect soil and vegetation properties that are key for the processes of runoff and soil erosion. However, both field and pot experiments show a vast range of effects, from strong reductions to strong increases in runoff and/or soil erosion. Therefore, this study aimed to quantify and interpret the impacts of biochar on runoff and soil erosion through the first systematic meta-analysis on this topic. The developed dataset consists of 184 pairwise observations for runoff and soil erosion from 30 independent studies but 8 of which just focused on soil erosion. Overall, biochar application to soil significantly reduced runoff by 25 % and erosion by 16 %. Mitigation of soil erosion in the tropics was approximately three times stronger (30 %) than at temperate latitudes (9 %); erosion reduction in the subtropical zone was 14 %, but not significantly different from either the tropical or temperate zones. Fewer reported field observations for runoff resulted in larger confidence intervals and only the temperate latitudes showed a significant effect (i.e. a 28 % reduction). At topsoil gravimetric biochar concentrations between 0.6 % and 2.5 %, significant reductions occurred in soil erosion, with no effect at lower and higher concentrations. Biochar experiments that included a vegetation cover reduced soil erosion more than twice as much as bare soil experiments, i.e. 27 % vs 12 %, respectively. This suggests that soil infiltration, canopy interception, and soil cohesion mechanisms may have synergistic effects. Soil amended with biochar pyrolyzed at >500 °C was associated with roughly double the erosion reduction than soil amended with biochar produced at 300-500 °C, which potentially could be related to the enhancement of hydrophobicity in the latter case. Our results demonstrate substantial potential for biochar to improve ecosystem services that are affected by increased infiltration and reduced erosion, while mechanistic understanding needs to be improved., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Behrouz Gholamahmadi reports financial support was provided by Foundation for Science and Technology. Frank Verheijen reports financial support was provided by Foundation for Science and Technology. Ana Catarina Bastos reports financial support was provided by Foundation for Science and Technology. Frank Verheijen reports financial support was provided by University of Aveiro Centre for Environmental and Marine Studies. Sergio Alegre Prats reports financial support was provided by Foundation for Science and Technology. Oscar Gonzalez-Pelayo reports financial support was provided by Foundation for Science and Technology. Jan Jacob Keizer reports financial support was provided by Foundation for Science and Technology., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Mulching is an effective post-fire soil erosion mitigation treatment. Experiments with forest residue mulch have demonstrated that it increased ground cover to 70% and reduced runoff and soil loss at small spatial scales and for short post-fire periods. However, no studies have systematically assessed the joint effects of scale, time since burning, and mulching on runoff, soil loss, and organic matter loss. The objective of this study was to evaluate the effects of scale and forest residue mulch using 0.25m 2 micro-plots and 100m 2 slope-scale plots in a burnt eucalypt plantation in central Portugal. We assessed the underlying processes involved in the post-fire hydrologic and erosive responses, particularly the effects of soil moisture and soil water repellency. Runoff amount in the micro-plots was more than ten-fold the runoff in the larger slope-scale plots in the first year and decreased to eight-fold in the third post-fire year. Soil losses in the micro-plots were initially about twice the values in the slope-scale plots and this ratio increased over time. The mulch greatly reduced the cumulative soil loss measured in the untreated slope-scale plots (616gm -2 ) by 91% during the five post-fire years. The implications are that applying forest residue mulch immediately after a wildfire can reduce soil losses at spatial scales of interest to land managers throughout the expected post-fire window of disturbance, and that mulching resulted in a substantial relative gain in soil organic matter., (Copyright © 2016 Elsevier B.V. All rights reserved.)

For several years now, forest fires have been known to increase overland flow and soil erosion. However, mitigation of these effects has been little studied, especially outside the USA. This study aimed to quantify the effectiveness of two so-called emergency treatments to reduce post-fire runoff and soil losses at the microplot scale in a eucalyptus plantation in north-central Portugal. The treatments involved the application of chopped eucalyptus bark mulch at a rate of 10-12 Mg ha(-1), and surface application of a dry, granular, anionic polyacrylamide (PAM) at a rate of 50 kg ha(-1). During the first year after a wildfire in 2010, 1419 mm of rainfall produced, on average, 785 mm of overland flow in the untreated plots and 8.4 Mg ha(-1) of soil losses. Mulching reduced these two figures significantly, by an average 52 and 93%, respectively. In contrast, the PAM-treated plots did not differ from the control plots, despite slightly lower runoff but higher soil erosion figures. When compared to the control plots, mean key factors for runoff and soil erosion were different in the case of the mulched but not the PAM plots. Notably, the plots on the lower half of the slope registered bigger runoff and erosion figures than those on the upper half of the slope. This could be explained by differences in fire intensity and, ultimately, in pre-fire standing biomass., (© 2013 Elsevier B.V. All rights reserved.)