Effects of forest residue mulching on organic matter and nutrient exports after wildfire in North-Central Portugal.

The quick implementation of emergency stabilization measures is vital for minimizing post-fire soil erosion and the associated fertility loss. Mulching has proven to be highly effective in minimizing post-fire soil erosion, however few studies have investigated its impacts on organic matter (OM) and nutrient mobilization from burned forest areas. This study evaluates the effectiveness of forest residue mulching at reducing OM, N and P losses within the sediments after a moderate-severity wildfire over a period of 5 years (Ermida, North-central Portugal). Untreated and mulched plots of ca. 100 m2 were bounded with geotextile fabric and sediments were collected from silt fences after a total of 29 periods. During the first five years after the fire, the accumulated OM, N and P exportations in the untreated plots were, respectively, 199, 5.2 and 0.38 g m-2; and mulch significantly reduced these figures in, respectively, 91 %, 94 % and 95 % (p < 0.05). The overall OM content in the sediments of the untreated plots (45 %) was not different from the OM content of the mulched plots (34 %, p = 0.16). However, the N (8.9 g kg-1) and Pav contents (0.62 g kg-1) in the untreated plots were significantly higher than the N (5.6 g kg-1; p < 0.05) and Pav contents (0.36 g kg-1; p < 0.05) in the mulched plots. This effect was especially noticeable in the first year after fire. OM and TN contents in the sediments were highly variable throughout the study period, whereas Pav contents declined sharply in the first post-fire rainfall events, maintaining low values afterwards. The main factors driving nutrient exports were ash and litter cover, whereas no significant relationship was observed for OM exports. The present work has shown that forest residues application can be a sustainable strategy for the conservation of soil carbon and nutrients in fire-affected areas.

Effectiveness of community-based initiatives for mitigation of land degradation after wildfires.

Local communities, informed about the main post-fire environmental threats, applied land restoration techniques after the 2017 Ponte Caldelas wildfire (Galicia, Spain). Volunteers crews, supervised by local researchers/technicians identified high-severity burned areas and applied: post-fire mulch by using corn mulch (chopped corn at a rate of 4 Mg ha-1), corn strip mulch (chopped corn on 1-m wide contourline-strips at the bottom of plots, at 1 Mg ha-1) and wheat mulch (wheat straw, at 2 Mg ha-1), as well as acorn seeding with native oak (Quercus robur) acorns. Furthermore, the mulch effect on seed germination/root elongation was tested in the laboratory using direct topsoil samples and <0.45 microns-filtered soil solutions. Soil erosion during the first post-fire year was 27-11 Mg ha-1 for the Parada-Laforet sites, respectively. Corn, corn strip, and wheat mulching were very effective at reducing soil erosion, leading to 95, 76% and 93% less erosion than in untreated plots. During post-fire year 2 mulching was still effective at reducing soil erosion in the case of corn (87%) and corn strip mulch (73%), but less effective with straw mulch (36%). For the third year no differences were observed. Acorn seedling establishment failed in 96% of the cases. Still, survival rate of the germinated acorns was significantly higher on the mulched (50%) than on the untreated spots (26%; p<0.05). The laboratory experiments also showed higher germination rates, shoot length and biomass in mulched than untreated soils. The results demonstrated that the mulching measures applied by the local volunteers were effective for preventing soil erosion after forest fires. The success of ecosystem restoration with acorn seeding was low due to the low germination and the high predation by rodents, and further research is needed to scale acorn seeding to natural recruitment rates.

Can straw-biochar mulching mitigate erosion of wildfire-degraded soils under extreme rainfall?

High severity wildfires cause a drastic alteration of soil carbon cycling - both oxidising and thermally altering soil organic matter (SOM) - and usually are followed by strong runoff and erosion events. To restore wildfire-degraded soils, SOM needs to be rebuilt while soil erosion is prevented. Post-fire straw mulching has been shown to mitigate soil erosion by providing a protective cover against rainsplash. However, SOM takes many decades or centuries to rebuilt naturally. Biochar, co-applied with straw to the soil surface can replace the SOM of the O-horizon, while the stabilised soil - by straw mulching - may gain in SOM naturally and by downward movement of biochar. We conducted a field study to test if straw-only and straw-biochar co-application could restore soils degraded by wildfire in one high burn severity (HBS) and one moderate burn severity (MBS) study area in southern Portugal and Spain, respectively, by monitoring erosion and SOM for the most intense rainfall period of the first post-fire year. Burned sites were characterized for soil and sediment physical properties, TOC content, SOM quality by thermogravimetry (DTG) and nuclear magnetic resonance (NMR 13C) spectroscopy. Straw-biochar mulching significantly reduced soil erosion by 76% and 65% in the HBS and MBS sites, respectively, in both cases similar to the erosion reduction by straw-only mulching. DTG and NMR 13C indicated that a relatively small proportion of the biochar eroded, i.e. 0.7%, indicating that co-application of straw with biochar may help restore the SOC lost in the wildfire in the medium term. The amount of SOM eroded was lower with straw-biochar mulching than in the untreated plots for both study areas. Straw-biochar mulching mitigates erosion of wildfire-degraded soils under extreme rainfall, while a relatively small proportion of the biochar is lost by erosion. Future studies need to monitor medium term effects.

Predicting the effectiveness of different mulching techniques in reducing post-fire runoff and erosion at plot scale with the RUSLE, MMF and PESERA models.

Wildfires have become a recurrent threat for many Mediterranean forest ecosystems. The characteristics of the Mediterranean climate, with its warm and dry summers and mild and wet winters, make this a region prone to wildfire occurrence as well as to post-fire soil erosion. This threat is expected to be aggravated in the future due to climate change and land management practices and planning. The wide recognition of wildfires as a driver for runoff and erosion in burnt forest areas has created a strong demand for model-based tools for predicting the post-fire hydrological and erosion response and, in particular, for predicting the effectiveness of post-fire management operations to mitigate these responses. In this study, the effectiveness of two post-fire treatments (hydromulch and natural pine needle mulch) in reducing post-fire runoff and soil erosion was evaluated against control conditions (i.e. untreated conditions), at different spatial scales. The main objective of this study was to use field data to evaluate the ability of different erosion models: (i) empirical (RUSLE), (ii) semi-empirical (MMF), and (iii) physically-based (PESERA), to predict the hydrological and erosive response as well as the effectiveness of different mulching techniques in fire-affected areas. The results of this study showed that all three models were reasonably able to reproduce the hydrological and erosive processes occurring in burned forest areas. In addition, it was demonstrated that the models can be calibrated at a small spatial scale (0.5 m2) but provide accurate results at greater spatial scales (10 m2). From this work, the RUSLE model seems to be ideal for fast and simple applications (i.e. prioritization of areas-at-risk) mainly due to its simplicity and reduced data requirements. On the other hand, the more complex MMF and PESERA models would be valuable as a base of a possible tool for assessing the risk of water contamination in fire-affected water bodies and for testing different land management scenarios.

Post-fire overland flow generation and inter-rill erosion under simulated rainfall in two eucalypt stands in north-central Portugal.

The aim of this study was to improve the existing knowledge of the runoff and inter-rill erosion response of forest stands following wildfire, focusing on commercial eucalypt plantations and employing field rainfall simulation experiments (RSE's). Repeated RSE's were carried out in two adjacent but contrasting eucalypt stands on steep hill slopes in north-central Portugal that suffered a moderate severity fire in July 2005. This was done at six occasions ranging from 3 to 24 months after the fire and using a paired-plot experimental design that comprised two pairs of RSE's at each site and occasion. Of the 46 RSE's: (i) 24 and 22 RSE's involved application rates of 45-50 and 80-85 mm h(-1), respectively; (ii) 22 took place in a stand that had been ploughed in down slope direction several years before the wildfire and 24 in an unploughed stand. The results showed a clear tendency for extreme-intensity RSE's to produce higher runoff amounts and greater soil and organic matter losses than the simultaneous high-intensity RSE's on the neighbouring plots. However, there existed marked exceptions, both in space (for one of the plot pairs) and time (under intermediate soil water repellency conditions). Also, overland flow generation and erosion varied significantly between the various field campaigns. This temporal pattern markedly differed from a straightforward decline with time-after-fire and rather suggested a seasonal component, reflecting broad variations in topsoil water repellency. The ploughed site produced less runoff and erosion than the unploughed site, contrary to what would be expected if the down slope ploughing had occurred after the wildfire instead of several years before it. Finally, sediment losses at both study sites were noticeably lower than those reported by other studies involving repeat RSE's, i.e. in Australia and western Spain. This possibly reflected a history of intensive land use in the study region, including in more recent times after the widespread introduction of eucalypt plantations.

Supervivencia y resultado funcional a largo plazo de prótesis de rodilla no cementadas / Uncemented knee arthroplasty: supervivorship and long-term functional outcome

Objetivo: Analizar la supervivencia a largo plazo y el resultado funcional de un modelo de prótesis de rodilla no cementada. Material y método: Realizamos un estudio prospectivo observacional de pacientes operados entre los años 1989 y 1996 con el modelo Low Contact Stress Mobile-Bearing Total Knee Replacement(R) (Depuy, Warsaw, IN, EE. UU.). Las variables estudiadas fueron edad, sexo, tiempo de seguimiento, puntuación del Knee Society Score (KSS), supervivencia del implante y motivos de la revisión. Un total de 96 artroplastias de 127 completaron el seguimiento. La media de edad fue de 79 años. La media de seguimiento fue de 14,5 años. Once prótesis se reintervinieron (6 por aflojamiento aséptico de implantes y 5 por problemas de componentes móviles). Se obtuvieron curvas de supervivencia al considerado el tiempo de seguimiento, el tiempo desde la cirugía primaria hasta la reintervención y el episodio «recambio por aflojamiento de componente metálico» y «necesidad de reintervención». Resultados: Las curvas de supervivencia arrojaron una supervivencia del 96,45% a los 9 años y del 92,78% a los 12 años, y se consideró la «necesidad de reintervención» como punto final. Al considerar la necesidad de recambio de componentes metálicos, la supervivencia a los 14 años y medio fue del 93,75%. La puntuación media del KSS funcional fue de 89,2. Conclusión: En nuestra experiencia y con el modelo protésico utilizado, las prótesis totales de rodilla no cementadas proporcionan un resultado clínico y funcional excelente, valorado por el KSS, y una supervivencia del 93,75% a los 14 años y medio al considerar la supervivencia del implante metálico (AU)

Purpose: To analyze the long term survivorship and functional results of a model of uncemented knee prosthesis. Materials and methods: We carried out a prospective observational study of patients implanted between 1989 and 1996 with the Low Contact Stress Mobile-Bearing Total Knee Replacement (Depuy, Warsaw, IN, EEUU). Variables studied included: age, gender, follow-up, Knee Society Score, implant survivorship and reasons for revision. A total of 96 arthroplasties out of 127 reached the end of follow-up Mean age was 79 years. Mean follow-up was 14 years. Eleven prostheses were revised (6 following aseptic loosening and 5 because of problems with the mobile bearings). Survivorship curves were obtained considering length of follow-up, time elapsed between the primary and the revision surgery and the “revision following loosening of a metal component” and “need for revision” events. Results: When "need for revision" was considered as the endpoint, survivorship curves revealed a survivorship rate of 96.45% at 9 years and 92.78% at 12 years. When the endpoint was the "need to revise metal components" 14.5-year survivorship was 93.75%. Mean Knee Society Score was 89.2 points. Conclusion: The use of the uncemented LCS knee has resulted in excellent clinical and functional results as measured by the Knee Society Score, as well as 93.75% survivorship at 14 years and a half, considering the survivorship of the metal implant (AU)

Simple and rapid analytical method for the simultaneous determination of cetrimonium chloride and alkyl alcohols in hair conditioners.

A simple method for the simultaneous determination of a cationic surfactant (cetrimonium chloride) and four non-ionic surfactants (1-tetradecanol, 1-hexadecanol, 1-octadecanol and 1-eicosanol) has been developed. Direct extraction of the analytes from the sample with methanol and a subsequent separation using reversed-phase high-performance liquid chromatography with refractive index detection are the steps followed in the procedure. The column used was a Luna C18 and the mobile phase consisted of a 0.1 M KClO(4) solution prepared on a 95:5 mixture of methanol and water. This solution was adjusted to pH 2.8 with phosphoric acid. Recoveries close to 100% were obtained in spiked commercial hair conditioner samples for the surfactants assayed using this method. Limits of detection were 10.4, 16.7 and 22.9 mg kg(-1) of cetrimonium chloride, 1-hexadecanol, 1-hexadecanol and 1-1-octadecanol respectively. The methodology was successfully applied to nine commercial hair conditioners of several types and different brands. All hair conditioners but one contained at least two of the surfactants included in this study.

La prótesis de rodilla dolorosa: enfoque diagnóstico / The painful knee prosthesis: a diagnostic approach

Introducción. La historia clínica y la exploración física son fundamentales para el enfoque diagnóstico de la prótesis de rodilla dolorosa. A la hora de planificar una estrategia diagnóstica es útil diferenciar entre problemas extraarticulares e intraarticulares.Diagnóstico y conclusiones. La radiología simple es la primera prueba complementaria a considerar, aportando en la mayoría de los casos información suficiente para establecer un diagnóstico. La tomografía axial computarizada será de utilidad para la valoración de áreas de osteólisis y alteracionesrotacionales de los componentes. La ecografía tiene utilidad en el estudio de las partes blandas periarticulares. Estudios recientes destacan el valor de la resonancia magnética nuclear para la valoración de la prótesis dolorosa. Desde el punto de vista analítico, la velocidad de sedimentación globular y la proteína C reactiva, pese a su baja especificidad, pueden ser de utilidad en el diagnóstico de laartroplastia total de rodilla infectada, especialmente si contamos con niveles seriados. Los estudios de Medicina Nuclear presentan una alta sensibilidad, aunque su especificidad es escasa. El uso de estudios isotópicos combinados (tecnecio e indio) puede ayudarnos al diagnóstico diferencial del aflojamiento protésico

Introduction. Clinical history and physical examination are essential factors for the diagnosis of the painful knee prosthesis. It is useful to make a distinction between extra andintra-articular problems before setting about planning for a diagnostic strategy. Diagnosis and conclusions. Plain films should be seen as the first supplementary imaging studies to be performed sincein most cases they contribute enough information to makea diagnosis. Computed axial tomography will be usefulto evaluate osteolytic areas and rotational alterations of the components. Ultrasound is useful for the analysis of periarticular soft tissues. Recent studies have emphasized the value of MRI for the assessment of the painful knee prosthesis. From the analytical viewpoint, the ESR and C-reactive protein, in spite of their low specificity, could be valuable tools in the diagnosis of infected total knee replacement, especiallyso if serial levels are available. Nuclear medicinestudies are highly sensitive, but their specificity is low. The use of combined isotope studies (technetium and indium) might help us with the differential diagnosis of prosthetic loosening

La prótesis de rodilla dolorosa: enfoque diagnóstico / The painful knee prosthesis: a diagnostic approach

Introducción. La historia clínica y la exploración física son fundamentales para el enfoque diagnóstico de la prótesis de rodilla dolorosa. A la hora de planificar una estrategia diagnóstica es útil diferenciar entre problemas extraarticulares e intraarticulares.Diagnóstico y conclusiones. La radiología simple es la primera prueba complementaria a considerar, aportando en la mayoría de los casos información suficiente para establecer un diagnóstico. La tomografía axial computarizada será de utilidad para la valoración de áreas de osteólisis y alteraciones rotacionales de los componentes. La ecografía tiene utilidad en el estudio de las partes blandas periarticulares. Estudiosrecientes destacan el valor de la resonanciamagnética nuclear para la valoración de la prótesis dolorosa. Desde el punto de vista analítico, la velocidad de sedimentación globular y la proteína C reactiva, pese a su baja especificidad, pueden ser de utilidad en el diagnóstico de la artroplastia total de rodilla infectada, especialmente si contamoscon niveles seriados. Los estudios de Medicina Nuclearpresentan una alta sensibilidad, aunque su especificidades escasa. El uso de estudios isotópicos combinados(tecnecio e indio) puede ayudarnos al diagnóstico diferencial del aflojamiento protésico

Introduction. Clinical history and physical examination are essential factors for the diagnosis of the painful knee prosthesis. It is useful to make a distinction between extra and intra-articular problems before setting about planning for a diagnostic strategy.Diagnosis and conclusions. Plain films should be seen asthe first supplementary imaging studies to be performed since in most cases they contribute enough information to make a diagnosis. Computed axial tomography will be useful to evaluate osteolytic areas and rotational alterations of the components. Ultrasound is useful for the analysis of periarticular soft tissues. Recent studies have emphasized the value of MRI for the assessment of the painful knee prosthesis.From the analytical viewpoint, the ESR and C-reactiveprotein, in spite of their low specificity, could be valuable tools in the diagnosis of infected total knee replacement, especially so if serial levels are available. Nuclear medicine studies are highly sensitive, but their specificity is low. Theuse of combined isotope studies (technetium and indium)might help us with the differential diagnosis of prosthetic loosening

La prótesis total de rodilla infectada / Infected total knee prosthesis

La infección profunda de la artroplastia total de rodilla es una complicación terrible. La profilaxis antibiótica y el extremo cuidado en el quirófano y en la cirugía son indispensables para evitar su presentación. Cuando, pese a todo, se sospecha una infección profunda, el diagnóstico precoz y la terapeútica agresiva, probablemente mediante el recambio en dos tiempos, pueden llevar a unos resultados aceptables, tanto en la resolución de la infección como en la obtención de una buena función articular; si no puede llevarse a cabo esta terapeútica, por un mal control de la infección, gran pérdida ósea o enfermedad general importante, habrá que valorar otras posibilidades de tratamiento como la supresión antibiótica, el desbridamiento agresivo y antibioterapia, la resección artroplastia, artrodesis o en último extremo, la amputación. Siempre se intentará controlar la infección y devolver a la articulación a un estado funcional aceptable (AU)

Results and complications of the low contact stress knee prosthesis.

We present the midterm results and complications of 101 low contact stress total knee replacements performed in 94 patients and reviewed at an average follow-up of 5.2 years (range, 4-8 years). The mean age at the time of surgery was 66 years (range, 53-76 years). Meniscal bearings were used in 83 knees and a rotating platform in the remaining 18 cases; cemented fixation was used only for 16 tibial components. At most recent follow-up, average knee and function scores were 93 and 78 points. None of the knees was revised because of loosening. Five knees showed distal femoral stress shielding. Complications included infection, supracondylar fracture, patellar component dislodgment, meniscal dislocation (2 cases), catastrophic wear of polyethylene, and progressive osteolysis (2 cases).

[Changes in the norms governing practices for the manufacture of pharmaceutical products: implications for the MERCOSUR]. / Evolucion de las normas oms sobre prácticas adecuadas de fabricación de productos farmacéuticos: su implicancia en el mercosur.

It is done a comparative study between the "Recommended rules for drug products manufacturing and inspection", approved in 1975 by the World Health Organization (and still in force in the MERCOSUR); and the standards published in 1992 by the WHO Expert Committee on Specifications for Pharmaceutical Preparations 32nd Report, named "Good Manufacturing Practices for pharmaceutical products". The correspondence between the regulation in force in the MERCOSUR and the Good Manufacturing Practices Inspection Guide for pharmaceutical industry, used by Health Authorities in the Common Market Member States, is analysed. It is noticed a disagreement between the rule in force and the instrument for verifying its fulfillment. The proposal of this article is the adoption by the Common Market Group, of the rules published by the WHO in 1992, and the establishment of an inspection guide which absolute agrees with it.