Search results for "leaf"
showing 10 items of 371 documents
Emergence of tomato leaf curl New Delhi virus in Italy: estimation of incidence and genetic diversity
2019
Tomato leaf curl New Delhi virus (ToLCNDV) is a bipartite begomovirus (family Geminiviridae) identified for the first time in 1995 in Asia, from where it spread into several countries of the Mediterranean basin. ToLCNDV was found in Spain in 2012, and subsequently in Tunisia and Italy. The first outbreak in Italy occurred at the end of 2015 in Trapani province (Sicily) on zucchini squashes. Then in 2016, ToLCNDV was found in infected zucchini plants in Campania, Lazio and Sardinia regions, and in 2017 in Calabria. This study addressed the dispersion and genetic diversity of ToLCNDV isolates in Italy. A total of 1400 plants were analysed. Phylogenetic analysis showed low variability among th…
Mapping evapotranspiration on vineyards: A comparison between Penman-Monteith and energy balance approaches for operational purposes
2012
Estimation of evapotranspiration (ET) in Sicilian vineyard is an emerging issue since these agricultural systems are more and more converted from rainfed to irrigated conditions, with significant impacts on the management of the scarce water resources of the region. The choice of the most appropriate methodology for assessing water use in these systems is still an issue of debating, due to the complexity of canopy and root systems and for their high spatial fragmentation. In vineyards, quality and quantity of the final product are dependent on the controlled stress conditions to be set trough irrigation. This paper reports an application of the well-known Penman-Monteith approach, applied i…
Alterations in the Microstructure of the Anterior Mitral Valve Leaflet Under Physiological Stress
2012
An improved understanding of mitral valve (MV) function remains an important goal for determining mechanisms underlying valve disease and for developing novel therapies. Critical to heart valve tissue homeostasis is the valvular interstitial cells (VICs), which reside in the interstitium and maintain the extracellular matrix (ECM) through both protein synthesis and enzymatic degradation [1]. There is scant quantitative experimental data on the alterations of the MV fiber network reorganization as a function of load, which is critical for implementation of computational strategies that attempt to link this meso-micro scale phenomenon. The observed large scale deformations experienced by VICs…
Accuracy assessment of fraction of vegetation cover and leaf area index estimates from pragmatic methods in a cropland area
2009
The fraction of vegetation cover (FVC) and the leaf area index (LAI) are important parameters for many agronomic, ecological and meteorological applications. Several in-situ and remote sensing techniques for estimating FVC and LAI have been developed in recent years. In this paper, the uncertainty of in-situ FVC and LAI measurements was evaluated by comparing estimates from LAI-2000 and digital hemispherical photography (DHP). The accuracy achieved with a spectral mixture analysis algorithm and two vegetation indices-based methods was assessed using atmospherically corrected Landsat Thematic Mapper (TM) data over the Barrax cropland area where the European Space Agency (ESA) SENtinel-2 and …
Direct validation of FVC, LAI and FAPAR VEGETATION/SPOT derived products using LSA SAF methodology
2007
The aim of this work is to perform a direct validation of fraction of vegetation cover (FVC), leaf area index (LAI) and fraction of absorbed photosynthetically active radiation (FAPAR) resulting products from applying the LSA SAF methodology to VEGETATION BRDF data. LSA SAF adapted algorithms were tested in adequate test sites comprising different continental biomes covering a wide range of FVC, LAI and FAPAR values. Results seem to indicate the competitiveness of LSA SAF proposed methodology to retrieve remotely sensed biophysical parameters. A noticeable good agreement regarding the ground measurements was found. The overall accuracy (RAISE) is around 20% for FVC and FAPAR and around 15% …
Integrating Domain Knowledge in Data-Driven Earth Observation With Process Convolutions
2022
The modelling of Earth observation data is a challenging problem, typically approached by either purely mechanistic or purely data-driven methods. Mechanistic models encode the domain knowledge and physical rules governing the system. Such models, however, need the correct specification of all interactions between variables in the problem and the appropriate parameterization is a challenge in itself. On the other hand, machine learning approaches are flexible data-driven tools, able to approximate arbitrarily complex functions, but lack interpretability and struggle when data is scarce or in extrapolation regimes. In this paper, we argue that hybrid learning schemes that combine both approa…
Evolution of Leaf Morphogenesis: Evidence from Developmental and Phylogenetic Data in Papaveraceae
1999
Variation of leaf morphology in Papaveraceae s.l. (including Fumariaceae and Pteridophyllum) has previously been shown to be related to developmental differences in the direction of segmentation and in blade‐petiole differentiation. Based on ontogenetic comparisons, we here distinguish polyternate, acropetal, basipetal‐pedate, basipetal‐pinnate, and divergent modes of dissection. In addition, undissected leaves occur in some taxa. Dissection modes can be grouped in two classes on the basis of blade‐petiole differentiation. Mapping of these morphogenetic traits on an independently obtained phylogenetic reconstruction reveals a high degree of homoplasy, indicating multiple evolutionary parall…
Bomba rice conservation with a natural biofilm
2018
[EN] The chemical composition of commercial Syzygium aromaticum, Cinnamomum verum, and Laurus nobilis essential oils as well as their antifungal activity against four pathogenic fungi isolated from Mediterranean rice grains has been investigated. Eighty nine compounds accounting for between 98.5 and 99.4% of the total essential oil were identified. The phenylpropanoids eugenol (89.37 ± 0.29%) and eugenol (56.34 ± 0.41%), followed by eugenol acetate (19.48 ± 0.13%) were, respectively, the main compounds in clove and cinnamon essential oils, whereas large amounts of the oxygenated monoterpenes 1,8-cineole (58.07 ± 0.83%) and ¿-terpinyl acetate (13.05 ± 0.44%) were found in bay leaf essential …
Retrieval of Crop Variables from Proximal Multispectral UAV Image Data Using PROSAIL in Maize Canopy
2022
Mapping crop variables at different growth stages is crucial to inform farmers and plant breeders about the crop status. For mapping purposes, inversion of canopy radiative transfer models (RTMs) is a viable alternative to parametric and non-parametric regression models, which often lack transferability in time and space. Due to the physical nature of RTMs, inversion outputs can be delivered in sound physical units that reflect the underlying processes in the canopy. In this study, we explored the capabilities of the coupled leaf–canopy RTM PROSAIL applied to high-spatial-resolution (0.015 m) multispectral unmanned aerial vehicle (UAV) data to retrieve the leaf chlorophyll content (LC…
Soil Moisture Retrieved From a Combined Optical and Passive Microwave Approach
2016
Abstract With the current remote sensing technology developments, and in particular those at L-band (1.2–1.4 GHz) frequencies such as the Soil Moisture and Ocean Salinity and the Soil Moisture Active and Passive missions, new approaches concerning passive microwave and its combination with existing optical technologies have become of special interest for the estimation of surface soil moisture. One of these new approaches is the combination of optical and passive microwave data based on a semiempirical approach derived from the general radiative transfer equation. The objective of this chapter is to present some applications of the combined optical-passive microwave approaches over several …