2,244 research outputs found
Stima della produttività di Vitis vinifera L., tramite un modello big-leaf
No full textIn order to assess primary productivity and transpiration of plant communities
several approaches are used. Here a modification of the model
developed by Vitale et al., based on the ‘big leaf’ approach, has
been used to model functional behaviour of Vitis vinifera L. Model
inputs are: latitude; mean temperature on monthly basis; maximum
photosynthesis rate; Quantum Yield as a temperature function; leaf
angle; reference temperature for respiration. Field gas-exchange measurements
were carried out at leaf level and it was necessary to make
some assumptions on canopy structure in order to avoid overestimation
of biomass production. These assumptions are required since canopies
structure in known to influence productivity and to determine
canopy conductance. The model estimates a crop net production of
186 g dry weight/m2, in accordance with field data. The model also
highlights the relationship between biomass production and canopy
structure in accordance with those productivity models based on
allometric relationship
Landsat-7 ETM+, Landsat-8 OLI, and Sentinel-2 MSI Surface Reflectance Cross-Comparison and Harmonization over the Mediterranean Basin Area
No full textIn the Mediterranean area, vegetation dynamics and phenology analysed over a long time can have an important role in highlighting changes in land use and cover as well as the effect of climate change. Over the last 30 years, remote sensing has played an essential role in bringing about these changes thanks to many types of observations and techniques. Satellite images are to be considered an important tool to grasp these dynamics and evaluate them in an inexpensive and multidisciplinary way thanks to Landsat and Sentinel satellite constellations. The integration of these tools holds a dual potential: on the one hand, allowing us to obtain a longer historical series of reflectance data, while on the other hand making data available with a higher frequency even within a specific timeframe. The study aims to conduct a comprehensive cross-comparison analysis of long-time-series pixel values in the Mediterranean regions. For this scope comparisons between Landsat-7 (ETM+), Landsat-8 (OLI), and Sentinel-2 (MSI) satellite sensors were conducted based on surface reflectance products. We evaluated these differences using Ordinary Least Squares (OLS) and Major Axis linear regression (RMA) analysis on points extracted from over 15,000 images across the Mediterranean basin area from 2017 to 2020. Minor but consistent differences were noted, necessitating the formulation of suitable adjustment equations to better align Sentinel-2 reflectance values with those of Landsat-7 or Landsat-8. The results of the analysis are compared with the most-used harmonization coefficients proposed in the literature, revealing significant differences. The root-mean-square deviation, the mean difference and the orthogonal distance regression (ODR) slope show an improvement of the parameters for both models used (OLS and RMA) in this study. The discrepancies in reflectance values leads to corresponding variations in the estimation of biophysical parameters, such as NDVI, showing an increase in the ODR slope of 0.3. Despite differences in spatial, spectral, and temporal characteristics, we demonstrate that integration of these datasets is feasible through the application of band-wise regression corrections for a sensitive and heterogeneous area like those of the Mediterranean basin area
Semiotica dell'eros maschile: rivelazione e sublimazione del desiderio fisico nel soggettivismo lirico di Philip Sidney, John Donne e William Shakespeare
No full textQuesto lavoro si propone di analizzare attraverso lo studio di tre dei più importanti canzonieri rinascimentali inglesi - "Astrophil and Stella" di Philip Sidney, i "Songs and Sonnets" di John Donne e i "Sonnets" di William Shakespeare - il concetto di eros maschile e quindi l’espressione del desiderio fisico nella sua manifestazione esplicita o implicita all’interno dei numerosi testi che compongono queste tre raccolte poetiche, mettendo in luce non solo la pluralità dei significati che esso assume nella cultura e nella mentalità inglese dell’epoca, ma cercando anche di esplicitare quelle considerazioni e/o valutazioni che emergono, con minore e maggiore rilevanza, dal confronto dei più disparati punti di vista, a vari livelli d’interpretazione testuale.
Un’indagine alla scoperta della plurivocità e dei registri linguistici del codice d’amore: la seduzione verbale, l’esibizionismo maschile, le forme dell’osceno in contrapposizione al platonismo estetico della bellezza ideale e della "cuncupiscientia animae".
Simmetria e senso dei ruoli intra-testuali: l’auto-rappresentazione del poeta, la costruzione della persona amata come oggetto ideale del desiderio fisico, e il voyeurismo del lettore.The main purpose of this research is to analyze three of the major lyric collections of the English Renaissance – "Astrophil and Stella" of Philip Sidney, the "Songs and Sonnets" of John Donne and the "Sonnets" of William Shakespeare – focusing attention on the representation of male eros and the physical desire, as conceived and expressed (in all their explicit or implicit manifestations) in the poetical compositions of the three chansonnieres. In this sense we wish to throw a new light upon the variety of meanings which male eros and the physical desire assume in the English culture and in the mentality of that age, and to make also clear all those aspects and/or assessments which (with more or less relevance) come out at different levels of textual interpretations from the comparison of the most diverse points of view.
The inquiry has been oriented to the discovery of the multi-voiced components and to the analysis of the several registers of the code of love: the study of verbal seduction, male exhibitionism, obscene language in contrast with the aesthetic Platonism concerning the idealized beauty and cuncupiscientia animae.
Sense and symmetry of textual roles: the self-representation of the poet, the outline of the beloved figure, and the voyeurism of the reader
The importance of local scale for assessing, monitoring and predicting of air quality in urban areas
No full textThe importance of the spatial scale for counteracting urban air pollution is highlighted in this work. In particular, the concept of Environmental Areas is used here in a wider sense than the current one. The Environmental Area is an area where the traffic conditions are more favourable for walkability and cycling compared to those of private motor vehicles. This work extends this concept to integrate several approaches coming from dimensional analysis, ecology, urban planning and transport engineering, to define a suitable spatial scale for an estimation of the PM10 removal through the street trees. Results highlight that, within the monitored area (the Monteverde neighbourhood, Rome Italy), the street trees are able to remove 0.142 t ha(-1) year(-1) of PM10 (about the 57% of the total particulate emission) with a re-suspension from plant canopies of 4%. Results have also demonstrated how is important an effective management of trees and the choice of appropriate trees made in according to the leaves' characteristics but also related to urban context in which trees are placed. We highlight that integrated planning among different elements of the public urban space is of great importance for ameliorating the urban liveability. Moreover, we remark that this Environmental Areas-based approach contributes to promote in citizens a greater knowledge of the territory and awareness of the dynamics that affect it and consequently a wider participation to public decisions concerning the choice, implementation and management of the street trees, reduction of car-based mobility and increase of pedestrian and cyclist mobility
Risposte ecofisiologiche alle condizioni ambientali estive di due specie legnose sempreverdi.
No full textDallo studio emerge l'importanza dei parametri micro-ambientali nell'influenzare l'andamento dell'attività fisiologica fogliare delle due specie analizzate. L'umidità relativa risulta essere un parametro importante nel controllo dell'attività stomatica, anche se in tal caso devono essere considerati anche i fattori endogeni. le due specie risultano essere particolarmente avvantaggiate, rispetto ad altre specie mediterranee, riguardo al mantenimento funzionale degli scambi gassosi, anche in condizioni ambientali limitanti
Physiological response of Pinus halepensis needles under ozone and water stress conditions
No full textThe aim of this study was to evaluate how physiological processes of potted Pinus halepensis plants, grown under controlled conditions, were affected by ozone (O3) and/or water stress, integrating the gas exchange and biochemical data with fluorescence OJIP polyphasic transient data. Plants submitted to only water stress (T1) and with ozone (T3) showed a strong decrease in stomatal conductance and gas exchange, coinciding with a reduction of maximum yield of photochemistry (φpo) and very negative values of leaf water potential. Simultaneously, a great increase of both PSII antenna size, indicated by absorption per reaction centre, and electron transport per reaction centre were found. The reduction of photosynthesis in the O3-treated plants (T2) by a slowing down of the Calvin cycle was supported by the increase of related fluorescence parameters such as relative variable fluorescence, heat de-excitation constant, energy deexcitation by spillover, and the decrease of φpo. We suggest an antagonistic effect between the two stresses to explain the delayed ozone-induced decrease of stomatal conductance values for T3with respect to T1 plants, by an alteration of the physiological mechanisms of stomatal opening, which involve the increase of intra-cellular free-calcium induced by ABA under co-occurring water shortage. We emphasise the importance of considering the intensity of the individual stress factor in studies concerning the interaction of stresses
Ecophysiological studies of Mediterranean plant species at the Castelporziano estate
No full textThe aim of this work was to characterize the eco-physiological performance of the main plant species of the Castelporziano site by single leaf investigations. We measured the leaf gas exchange of Quercus ilex L., Pinus pinea L., Pistacia lentiscus L. and Asphodelus microcarpus I,. for several days. Additionally, the xylem water potential of Quercus ilex, Pinus pinea and Pistacia lentiscus was recorded in order to obtain more physiological background information for the discussion of the trace gas emissions. This study indicates significantly different physiological responses to the different environmental conditions. In particular, summer conditions (high values of light, air temperature and low xylem water potentials) caused the depression of photosynthesis in Quercus ilex and Pinus pinea but did not affect photosynthesis of Pistacia lentiscus and Asphodelus microcarpus. This should be taken into account when discussing VOC emission rates and fluxes. (C) 1997 Elsevier Science Ltd
Operational Experience of the Gas Gain Monitoring system of the CMS RPC muon detectors
No full textPerformances of the Gas Gain Monitoring system of the CMS RPC muon detectors after one year of operation at the scaled down closed loop recirculation gas system are presented. The GGM is made of 12 single-gap RPC's arranged in a cosmic ray telescope, with charge readout for online monitoring of working point. Preliminary results on sensitivity to gas changes and to environmental variables will be reported on. (C) 2009 Elsevier B.V. All rights reserved
Resistive plate chamber commissioning and performance in CMS
No full textThe CMS muon system is conceived for trigger and muon track reconstruction. The redundancy and robustness of the system are guaranteed by three complementary subsystems: drift tube in the barrel, cathode strip chamber in the end-cap and resistive plate chamber in barrel and end-cap. The installation of muon stations and read-out trigger electronic has been completed in middle 2007. Since than, a remarkable effort has been addressed to the detector commissioning in order to ensure the readiness of the hardware/software chain for the LHC start up operation. At the end of 2007, a test of an entire CMS slice has been performed. involving about 5% of muon stations. Several thousand cosmic muons events have been collected. Performance of the barrel chambers are reported. (C) 2008 Elsevier B.V. All rights reserved
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