N2O and CH4 fluxes in Undisturbed and Burned Holm oak, Scots pine and Pyrenean oak forests in Central Spain

We investigated N2O and CH4 fluxes from soils of Quercus ilex, Quercus pyrenaica and Pinus sylvestris stands located in the surrounding area of Madrid (Spain). The fluxes were measured for 18 months from both mature stands and post fire stands using the static chamber technique. Simultaneously with gas fluxes, soil temperature, soil water content, soil C and soil N were measured in the stands. Nitrous oxide fluxes ranged from −11.43 to 8.34 μg N2O–N m−2 h−1 in Q.ilex, −7.74 to 13.52 μg N2O–N m−2 h−1 in Q. pyrenaica and −28.17 to 21.89 μg N2O–N m−2 h−1 in P. sylvestris. Fluxes of CH4 ranged from −8.12 to 4.11 μg CH4–C m−2 h−1 in Q.ilex, −7.74 to 3.0 μg CH4–C m−2 h−1 in Q. pyrenaica and −24.46 to 6.07 μg CH4–C m−2 h−1 in P. sylvestris. Seasonal differences were detected; N2O fluxes being higher in wet months whereas N2O fluxes declined in dry months. Net consumption of N2O was related to low N availability, high soil C contents, high soil temperatures and low moisture content. Fire decreased N2O fluxes in spring. N2O emissions were closely correlated with previous day’s rainfall and soil moisture. Our ecosystems generally were a sink for methane in the dry season and a source of CH4 during wet months. The available water in the soil influenced the observed seasonal trend. The burned sites showed higher CH4 oxidation rates in Q. ilex, and lower rates in P. sylvestris. Overall, the data suggest that fire alters both N2O and CH4 fluxes. However, the magnitude of such variation depends on the site, soil characteristics and seasonal climatic conditions

Anestesia neuroaxial combinada con anestesia general en la cirugía coronaria sin circulación extracorpórea. Ensayo clínico controlado aleatorizado. Resultados preliminares. Neuraxial anesthesia combined with general anesthesia in off pump coronary artery bypass graft surgery. A clinical controlled randomized study. Preliminary results.

Introducción: En Cuba más del 50% de la cirugía coronaria se realiza a corazón batiente.La anestesia general orotraqueal ha sido la técnica utilizada en nuestroservicio. La anestesia neuroaxial combinada con el método anestésico general,en esta última década, ha prevalecido en parte de los cardiocentrosdel mundo, debido a sus innegables ventajas.Objetivos: Evaluar los efectos de la anestesia general combinada con bloqueo epiduraltoráxico alto o administración intratecal de morfina/fentanil sobre laanalgesia perioperatoria, tiempo de extubación, estancia en unidad decuidados intensivos y estancia hospitalaria. Identificar la frecuencia deaparición de efectos adversos relacionados con la administración de opioidespor vía espinal y la frecuencia de aparición de complicaciones relacionadascon el método de anestésico regional.Método: Ensayo clínico controlado y aleatorizado en pacientes con diagnóstico decardiopatía isquémica, programados para procedimiento quirúrgico de revascularizaciónmiocárdica sin circulación extracorpórea. Los enfermos seasignaron a uno de los tres grupos siguientes: Grupo control (n=30):Método anestésico general orotraqueal. Grupo multimodal con epidural torácica (n=29): Dosis de 10 ml de bupivacaína al 0,5% (50 mg), más 5mg de morfina. Grupo multimodal con opioide intratecal (n=29): administraciónintratecal de 1,5 μg/kg. de peso de fentanil más 8 μg/ kg de pesode morfina.Resultados: La analgesia perioperatoria fue más efectiva en los grupos multimodales.El tiempo de extubación y la estadía en unidad de cuidados intensivos fuemenor en ambos grupos multimodales, pero dichos métodos no influyeronen la estadía hospitalaria. No se observó complicación neurológica asociadaa los bloqueos neuroaxiles.Conclusiones: Los métodos anestésicos multimodales son superiores.Introduction: In Cuba more than 50% of the coronary surgery is carried out with thebeating heart modality. Endotracheal general anesthesia has been thetechnique used in our service. Neuraxial anesthesia combined with thegeneral anesthesia method, in this last decade, has prevailed in a certainnumber of the cardiovascular centers of the world, due to their undeniableadvantages.Objectives: To evaluate the effects of the general anesthesia combined with highthoracic epidural blockade or intrathecal administration of morphine/fentanil on the intraoperative analgesia, time of extubation, intensivecare unit and hospital stay. To identify the frequency of appearanceof adverse effects related with the spinal administration of opioidsand the frequency of appearance of complications related with regionalanesthetic's method.Method: A controlled randomized trial was conducted in patients with diagnosisof coronary heart disease, programmed for off pump coronary arterybypass graft surgery. This patients were assigned to one of the followingthree groups: Control group (n=30): Endotracheal general anestheticmethod. Multimodal group (n=29) with thoracic epidural anesthesia:bupivacaína 0,5% (50 mg) 10 ml/single dose and 5 mg of morphine.Multimodal group with intrathecal administration of opioids(n=29): fentanil 1,5 μg/kg and morphine 8 μg/kg.Results: The intraoperative analgesia was more effective in the multimodalgroups. The time of extubation and the intensive care unit stay weresmaller in both multimodal groups, but this methods didn't influence inthe hospital stay. Neurological complications associated to neuraxialblockade was not observed.Conclusions: The multimodal anesthetic methods are superior

Flujos de CO2 del suelo en rebollares y pinares de Pino Albar de la Sierra de Guadarrama

El objetivo primordial del trabajo es la investigación de los principales factores que regulan la variabilidad espacial de los flujos de CO2 del suelo (o respiración del suelo, RS) en suelos de pino albary rebollar de la vertiente norte de la Sierra de Guadarrama. Para ello se establecieron dos transectos, uno a lo largo de un gradiente altitudinal de Pinus sylvestris L., y el otro constituido alrededor del ecotono entre P. sylvestris L. y Quercus pyrenaica Lam. El flujo de CO2, la temperatura y la humedad del suelo se midieron mensualmente durante un año y se determinaron los parámetros fisicoquímicos y microbiológicos del mismo. La RS mostró un patrón estacional típico con valores mínimos en invierno y máximos en primavera. Los valores máximos de RS se obtuvieron en las parcelas situadas a mayor altitud, en el pinar durante el invierno y en el rebollar durante la primavera y el verano. Los valores de los parámetros Q10 y R10 fueron menores que los descritos en la bibliografía para ecosistemas forestales. En nuestras condiciones los modelos de Q10 para el cálculo de RS no son los más adecuados a no ser que se tengan en consideración otros parámetros del suelo además de la temperatura, tales como la relación C/N, la humedad del suelo y el contenido en carbono de la biomasa microbiana

Flujos de CO2 del suelo en rebollares y pinares de Pino Albar de la Sierra de Guadarrama

El objetivo primordial del trabajo es la investigación de los principales factores que regulan la variabilidad espacial de los flujos de CO2 del suelo (o respiración del suelo, RS) en suelos de pino albary rebollar de la vertiente norte de la Sierra de Guadarrama. Para ello se establecieron dos transectos, uno a lo largo de un gradiente altitudinal de Pinus sylvestris L., y el otro constituido alrededor del ecotono entre P. sylvestris L. y Quercus pyrenaica Lam. El flujo de CO2, la temperatura y la humedad del suelo se midieron mensualmente durante un año y se determinaron los parámetros fisicoquímicos y microbiológicos del mismo. La RS mostró un patrón estacional típico con valores mínimos en invierno y máximos en primavera. Los valores máximos de RS se obtuvieron en las parcelas situadas a mayor altitud, en el pinar durante el invierno y en el rebollar durante la primavera y el verano. Los valores de los parámetros Q10 y R10 fueron menores que los descritos en la bibliografía para ecosistemas forestales. En nuestras condiciones los modelos de Q10 para el cálculo de RS no son los más adecuados a no ser que se tengan en consideración otros parámetros del suelo además de la temperatura, tales como la relación C/N, la humedad del suelo y el contenido en carbono de la biomasa microbiana

Investigating mountain breezes characteristics and their effects on CO2 concentration at three different sites

International audienceThe characteristics of daytime and nighttime mountain breezes have been analysed and compared at three different sites: a) in the foothills of the Guadarrama Mountain range (El Escorial, Spain); b) on a plateau close to The Pyrenees (Lannemezan, France); and c) in the Salt Lake Valley (SLV, Utah, US). A systematic algorithm, based on synoptic and local meteorological conditions, has been used to detect automatically numerous events at each site. On the one hand, the wind characteristics of these mountain breezes depend on the scale of the breeze detected at each site. Their arrivals are observed approximately when the sensible heat flux changes sign, but they are delayed in the sites that are farther away from the mountains. On the other hand, the effects of these breezes on CO2 mixing ratios have been investigated. The typical increases and decreases of CO2 mixing ratios observed around the afternoon and morning transition do not always occur at the same time of the breeze arrival to the tower site, which unlinks these drastic changes in CO2 from the direct horizontal advection produced by the breezes. However, the CO2 mixing ratio is sensitive to changes in wind direction in highly heterogeneous sites, like the SLV site. Besides, the changes in surface turbulence produced by the breezes have an important effect on CO2. Indeed, a clear relationship is found for CO2 mixing ratio and the turbulent kinetic energy in the lowest atmospheric layers during the nighttime events

Investigating mountain breezes characteristics and their effects on CO2 concentration at three different sites

International audienceThe characteristics of daytime and nighttime mountain breezes have been analysed and compared at three different sites: a) in the foothills of the Guadarrama Mountain range (El Escorial, Spain); b) on a plateau close to The Pyrenees (Lannemezan, France); and c) in the Salt Lake Valley (SLV, Utah, US). A systematic algorithm, based on synoptic and local meteorological conditions, has been used to detect automatically numerous events at each site. On the one hand, the wind characteristics of these mountain breezes depend on the scale of the breeze detected at each site. Their arrivals are observed approximately when the sensible heat flux changes sign, but they are delayed in the sites that are farther away from the mountains. On the other hand, the effects of these breezes on CO2 mixing ratios have been investigated. The typical increases and decreases of CO2 mixing ratios observed around the afternoon and morning transition do not always occur at the same time of the breeze arrival to the tower site, which unlinks these drastic changes in CO2 from the direct horizontal advection produced by the breezes. However, the CO2 mixing ratio is sensitive to changes in wind direction in highly heterogeneous sites, like the SLV site. Besides, the changes in surface turbulence produced by the breezes have an important effect on CO2. Indeed, a clear relationship is found for CO2 mixing ratio and the turbulent kinetic energy in the lowest atmospheric layers during the nighttime events