Search results for " forest"

Adsorption et desorption de la terbutryne par une montmorillonite-Ca et des acides humiques seuls ou en melanges

1977

Resume: L' effet du pH sur l'adsorption de la terbutryne par des acides humiques, une montmorillonite-Ca ou leurs melanges montre une certaine similitude de comportement entre ces derniers et l'argile seule. Au voisinage de la neutralite, seuls les acides humiques adsorbent la terbutryne. En milieu acide, les isothermes d'adsorption de la terbutryne par les acides humiques et la montmorillonite sont respectivement de type L et S et traduisent une affinite adsorbat-adsorbant differente; les isothermes d'adsorption correspondant aux melanges ont une forme differente et font apparaitre un effet de synergie, en particulier dans le cas des melanges pauvres en acides humiques. La dsorption saccom…

Cell state prediction through distributed estimation of transmit power

2019

Determining the state of each cell, for instance, cell outages, in a densely deployed cellular network is a difficult problem. Several prior studies have used minimization of drive test (MDT) reports to detect cell outages. In this paper, we propose a two step process. First, using the MDT reports, we estimate the serving base station’s transmit power for each user. Second, we learn summary statistics of estimated transmit power for various networks states and use these to classify the network state on test data. Our approach is able to achieve an accuracy of 96% on an NS-3 simulation dataset. Decision tree, random forest and SVM classifiers were able to achieve a classification accuracy of…

Creación de un modelo estadístico predictivo para la determinación de las funciones de atenuación en español hablado

2018

Recientemente, algunos autores han definido distintas variables para caracterizar la atenuación lingüística en el marco de una base de datos multidimensional (Briz/Albelda; Albelda/otros). En este estudio se han seleccionado 982 elementos de atenuación de dieciocho entrevistas de español hablado; todos ellos han sido supervisados por hasta cuatro entrevistadores del proyecto Es.VaG.Atenuación. Finalmente, los datos se han evaluado mediante tres pruebas estadísticas para la clasificación y la reducción de variables: el análisis múltiple de correspondencias, el árbol de clasificaciones y el Random Forest. Las variables más determinantes en la discriminación de las funciones de atenuación han …

Proactive avoidance behaviour and pace-of-life syndrome in Atlantic salmon

2019

Individuals in a fish population differ in key life-history traits such as growth rate and body size. This raises the question of whether such traits cluster along a fast-slow growth continuum according to a pace-of-life syndrome (POLS). Fish species like salmonids may develop a bimodal size distribution, providing an opportunity to study the relationships between individual growth and behavioural responsiveness. Here we test whether proactive characteristics (bold behaviour coupled with low post-stress cortisol production) are related to fast growth and developmental rate in Atlantic salmon, Salmo salar . Boldness was tested in a highly controlled two-tank hypoxia test were oxygen levels …

Snowpack concentrations and estimated fluxes of volatile organic compounds in a boreal forest

2012

Abstract. Soil provides an important source of volatile organic compounds (VOCs) to atmosphere, but in boreal forests these fluxes and their seasonal variations have not been characterized in detail. Especially wintertime fluxes are almost completely unstudied. In this study, we measured the VOC concentrations inside the snowpack in a boreal Scots pine (Pinus sylvestris L.) forest in southern Finland, using adsorbent tubes and air samplers installed permanently in the snow profile. Based on the VOC concentrations at three heights inside the snowpack, we estimated the fluxes of these gases. We measured 20 VOCs from the snowpack, monoterpenes being the most abundant group with concentrations …

Compensation of Oxygen Transmittance Effects for Proximal Sensing Retrieval of Canopy–Leaving Sun–Induced Chlorophyll Fluorescence

2018

Estimates of Sun–Induced vegetation chlorophyll Fluorescence (SIF) using remote sensing techniques are commonly determined by exploiting solar and/or telluric absorption features. When SIF is retrieved in the strong oxygen (O 2 ) absorption features, atmospheric effects must always be compensated. Whereas correction of atmospheric effects is a standard airborne or satellite data processing step, there is no consensus regarding whether it is required for SIF proximal–sensing measurements nor what is the best strategy to be followed. Thus, by using simulated data, this work provides a comprehensive analysis about how atmospheric effects impact SIF estimations on proximal sensing, regarding: (…

2021

Nitrogen (N) is one of the key nutrients supplied in agricultural production worldwide. Over-fertilization can have negative influences on the field and the regional level (e.g., agro-ecosystems). Remote sensing of the plant N of field crops presents a valuable tool for the monitoring of N flows in agro-ecosystems. Available data for validation of satellite-based remote sensing of N is scarce. Therefore, in this study, field spectrometer measurements were used to simulate data of the Sentinel-2 (S2) satellites developed for vegetation monitoring by the ESA. The prediction performance of normalized ratio indices (NRIs), random forest regression (RFR) and Gaussian processes regression (GPR) f…

Sentinel-1 & Sentinel-2 Data for Soil Tillage Change Detection

2018

In this paper, an algorithm using Sentinel-1 (S-1) and Sentinel-2 (S-2) data to identify changes of tillage over agricultural fields at approximately similar to 100m resolution is presented. The methodology implements a multiscale temporal change detection on S-1 VH backscatter in order to single out VH changes due to agricultural practices only. The algorithm can be applied over bare or scarcely vegetated agricultural fields, which are identified from S-2 NDVI measurements. An initial assessment at farm scale using in situ and S-1 and SPOT5-Take5 data, acquired over the Apulian Tavoliere in southern Italy in 2015, is illustrated. A full validation of the approach is in progress over three …

The effect of substituted urea herbicides on the growth of excised tomato roots

1983

Summary The action of 23 herbictdal substituted ureas on the growth of excised tomato roots was studied in order to determine whether there is a link between the effects of these herbicides on oxidative phosphorylation and on the growth of non-photosynthetic tissues. Fourteen of these herbicides were inhibitory; chlortoluron and TBU were stimulatory but only in the light. Substituted ureas known to affect plant mitochondria inhibited root growth but to a lesser extent than some which had no action on mitochondria. No clear relationship was found between actions on mitochondria and on root growth. It is suggested that targets other than photosynthesis and oxidative phosphorylation exist for …

Behaviour of the herbicide EL-107 in wheat and rape grown under controlled conditions

1987

Summary The behaviour of 14C-EL-107 has been evaluated in winter wheat and rape, which are tolerant and susceptible, respectively, under field conditions. After 10- to 13-days’growth under controlled conditions, seedlings were allowed to absorb the herbicide through the roots. Two experiments were conducted to study the absorption and the metabolism of EL-107. Absorption was estimated during a 5-day treatment at the rate of 1–47 μM, and metabolism was studied after a 1-day treatment at 14.7 μM. The results showed that (i) rape plants absorbed more herbicide than wheat, and translocated less radioactivity into their shoots, and (ii) the metabolism of EL-107 proceeded actively only in the sho…