Search results for " Biophysical"
showing 10 items of 13 documents
LAI, FAPAR and FCOVER ground-truth map creation from FASat-C satellite imagery and in-situ measurements in Chimbarongo, Chile, for satellite products…
2016
[EN] In remote sensing, validation exercises are essential to ensure the quality of the products originated from satellite Earth observations. To assess the measurement uncertainty derived from satellite products, several ground field data from different ecosystems must be available for use. In the same order of importance, it is necessary to define data sampling and up-scaling methodologies to allow a suitable comparison between the ground data and the pixel size of the product. This paper shows the applied methodology used in the FP7 ImagineS project (Implementing Multi-scale Agricultural Indicators Exploiting Sentinels) to validate 10-days global LAI, FAPAR and vegetation cover products …
Optimal modalities for radiative transfer-neural network estimation of canopy biophysical characteristics: Evaluation over an agricultural area with …
2011
International audience; Neural networks trained over radiative transfer simulations constitute the basis of several operational algorithms to estimate canopy biophysical variables from satellite reflectance measurements. However, only little attention was paid to the training process which has a major impact on retrieval performances. This study focused on the several modalities of the training process within neural network estimation of LAI, FCOVER and FAPAR biophysical variables. Performances were evaluated over both actual experimental observations and model simulations. The SAIL and PROSPECT radiative transfer models were used here to simulate the training and the synthetic test dataset…
Overcome Chemoresistance: Biophysical and Structural Analysis of Synthetic FHIT-Derived Peptides.
2021
The fragile histidine triad (FHIT) protein is a member of the large and ubiquitous histidine triad (HIT) family of proteins. On the basis of genetic evidence, it has been postulated that the FHIT protein may function as tumor suppressor, implying a role for the FHIT protein in carcinogenesis. Recently, Gaudio et al. reported that FHIT binds and delocalizes annexin A4 (ANXA4) from plasma membrane to cytosol in paclitaxel-resistant lung cancer cells, thus restoring their chemosensitivity to the drug. They also identified the smallest protein sequence of the FHIT still interacting with ANXA4, ranging from position 7 to 13: QHLIKPS. This short sequence of FHIT protein was not only able to bind …
Climate Data Records of Vegetation Variables from Geostationary SEVIRI/MSG Data: Products, Algorithms and Applications
2019
The scientific community requires long-term data records with well-characterized uncertainty and suitable for modeling terrestrial ecosystems and energy cycles at regional and global scales. This paper presents the methodology currently developed in EUMETSAT within its Satellite Application Facility for Land Surface Analysis (LSA SAF) to generate biophysical variables from the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) on board MSG 1-4 (Meteosat 8-11) geostationary satellites. Using this methodology, the LSA SAF generates and disseminates at a time a suite of vegetation products, such as the leaf area index (LAI), the fraction of the photosynthetically active radiation absorbed …
Influence of noise sources on FitzHugh-Nagumo model in suprathreshold regime
2005
We study the response time of a neuron in the transient regime of FitzHugh-Nagumo model, in the presence of a suprathreshold signal and noise sources. In the deterministic regime we find that the activation time of the neuron has a minimum as a function of the signal driving frequency. In the stochastic regime we consider two cases: (a) the fast variable of the model is noisy, and (b) the slow variable, that is the recovery variable, is subjected to fluctuations. In both cases we find two noise-induced effects, namely the resonant activation-like and the noise enhanced stability phenomena. The role of these noise-induced effects is analyzed. The first one produces suppression of noises, whi…
Environmental Noise and Nonlinear Relaxation in Biological Systems
2012
We analyse the effects of environmental noise in three different biological systems: (i) mating behaviour of individuals of 'Nezara viridula' (L.) (Heteroptera Pentatomidae); (ii) polymer translocation in crowded solution; (iii) an ecosystem described by a Verhulst model with a multiplicative Lèvy noise. Specifically, we report on experiments on the behavioural response of 'N. viridula' individuals to sub-threshold deterministic signals in the presence of noise. We analyse the insect response by directionality tests performed on a group of male individuals at different noise intensities. The percentage of insects which react to the sub-threshold signal shows a non-monotonic behavior, charac…
Mathematical models for the diffusion magnetic resonance signal abnormality in patients with prion diseases
2014
In clinical practice signal hyperintensity in the cortex and/or in the striatum on magnetic resonance (MR) diffusion-weighted images (DWIs) is a marker of sporadic Creutzfeldt–Jakob Disease (sCJD). MR diagnostic accuracy is greater than 90%, but the biophysical mechanisms underpinning the signal abnormality are unknown. The aim of this prospective study is to combine an advanced DWI protocol with new mathematical models of the microstructural changes occurring in prion disease patients to investigate the cause of MR signal alterations. This underpins the later development of more sensitive and specific image-based biomarkers. DWI data with a wide a range of echo times and diffusion weightin…
Glossary of terms used in photocatalysis and radiation catalysis (IUPAC Recommendations 2011)
2011
This glossary of terms covers phenomena considered under the very wide terms photocatalysis and radiation catalysis. A clear distinction is made between phenomena related to either photochemistry and photocatalysis or radiation chemistry and radiation catalysis. The term “radiation” is used here as embracing electromagnetic radiation of all wavelengths, but in general excluding fast-moving particles. Consistent definitions are given of terms in the areas mentioned above, as well as definitions of the most important parameters used for the quantitative description of the phenomena. Terms related to the up-scaling of photocatalytic processes for industrial applications have been included. Thi…
A bioenergetics framework for integrating the effects of multiple stressors: Opening a 'black box' in climate change research
2015
Climate change is already impacting marine ecosystems across a range of scales, from individual physiology, to changes in species interactions and community structure, and ultimately to patterns in geographic distribution. Predicting how marine ecosystems will respond to environmental change is a signifi cant challenge because vulnerability to climatic and non-climatic stressors is highly variable, and depends on an organism’s functional traits, tolerance to stressors, and the environment in which it lives. We present a mechanistic approach based on biophysical and dynamic energy budget models that integrates the cumulative effects of multiple environmental stressors (temperature and food) …
Evidence of stochastic resonance in the mating behavior of Nezara viridula (L.)
2008
We investigate the role of the noise in the mating behavior between individuals of Nezara viridula (L.), by analyzing the temporal and spectral features of the non-pulsed type female calling song emitted by single individuals. We have measured the threshold level for the signal detection, by performing experiments with the calling signal at different intensities and analyzing the insect response by directionality tests performed on a group of male individuals. By using a sub-threshold signal and an acoustic Gaussian noise source, we have investigated the insect response for different levels of noise, finding behavioral activation for suitable noise intensities. In particular, the percentage…