Search results for "CONDUCTANCE"

Global uptake of carbonyl sulfide (COS) by terrestrial vegetation: Estimates corrected by deposition velocities normalized to the uptake of carbon di…

2005

Abstract. COS uptake by trees, as observed under dark/light changes and under application of the plant hormone abscisic acid, exhibited a strong correlation with the CO2 assimilation rate and the stomatal conductance. As the uptake of COS occurred exclusively through the stomata we compared experimentally derived and re-evaluated deposition velocities (Vd; related to stomatal conductance) for COS and CO2. We show that Vd of COS is generally significantly larger than that of CO2. We therefore introduced this attribute into a new global estimate of COS fluxes into vegetation. The new global estimate of the COS uptake based on available net primary productivity data (NPP) ranges between 0.69-1…

Experimental investigation of the kink effect and the low frequency noise properties in pseudomorphic HEMT’s

2005

The kink effect in low-noise pseudomorphic (AlGaAs/InGaAs) HEMT's has been examined in detail by investigating the steady-state and pulsed I-V characteristics, the behavior of the output conductance dispersion and the performance of the gate leakage current to understand its origin. No clear evidence of impact ionization occurrence in the InGaAs channel at kink bias conditions (V-DS.kink = 1.5 V) has been found, thus suggesting that the predominant mechanism should be attributed to trap-related phenomena. A significant rise of the gate current has been found at very high drain voltages (far from V-DS.kink) associated with low drain current values which is probably due to impact ionization o…

Visualization of Molecular Recognition Events on Microstructured Lipid-Membrane Compartments by In Situ Scanning Force Microscopy This work was suppo…

2002

CFTR p.Arg117His associated with CBAVD and other CFTR-related disorders

2013

International audience; BACKGROUND:The high frequency of the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) gene mutation p.Arg117His in patients with congenital bilateral absence of the vas deferens (CBAVD) and in newborns screened for CF has created a dilemma.METHODS:Phenotypic and genotypic data were retrospectively collected in 179 non-newborn French individuals carrying p.Arg117His and a second CFTR mutation referred for symptoms or family history, by all French molecular genetics laboratories, referring physicians, CF care centres and infertility clinics.RESULTS:97% of the patients had the intronic T7 normal variant in cis with p.Arg117His. 89% patients were male, wit…

Complexes of organometallic compounds

1974

Abstract Tetraphenylarsonium and tetramethylammonium salts of the complex anions Ph 3 Pb(N 3 ) − 2 , Ph 3 Pb(N 3 )(NCS) − , Ph 2 Pb(N 3 ( 2 − 4 )) and Ph 2 Pb(N 3 )(NCS) − 2 have been prepared and characterized. Infrared spectra and solution conductance data are reported. Possible configurations of the complex anions are discussed.

Plant response to irrigation with saline water in a Sicilian vineyard: results of a three-years field investigation

2012

This paper reports the results of a three-year field investigation carried out in a vineyard located in Sicily (Mazara del Vallo, Trapani) within the framework of the Project: Evolution of cropping systems as affected by climate change (CLIMESCO). Research investigated soil-plant response to irrigation performed with water having two different salinity levels; soil hydrological characteristics, soil salinity, crop transpiration and stomatal conductance were measured in field plots. The results proved that crop transpiration and stomatal conductance were significantly affected by soil salinity conditions (expressed as electrical conductivity of the soil saturated water extract). A significan…

The effect of saline water on Phillyrea angustifolia L. seedlings

2013

Water limitations in the Mediterranean areas are very common and the use of saline water for plant irrigation is becoming a necessity. Salinity generally affects plant growth and physiological processes, and can eventually lead to leaf injuries and plant death. For these reasons, the selection of salt tolerant species is a priority for landscaping purposes in the Mediterranean areas. The objective of this study was to evaluate the effect of saline water on Phillyrea angustifolia plant performance. Seventy-five rooted cuttings were grown in the greenhouse in 4-liter pots and irrigated for 5 months with saline water at different NaCl concentrations for two consecutive years. In 2010, 45 plant…

Does short-term potassium fertilization improve recovery from drought stress in laurel?

2014

Xylem hydraulic conductance varies in response to changes in sap solute content, and in particular of potassium (K(+)) ion concentration. This phenomenon, known as the 'ionic effect', is enhanced in embolized stems, where it can compensate for cavitation-induced loss of hydraulic conductance. Previous studies have shown that in well-watered laurel plants (Laurus nobilis L.), potassium concentration of the xylem sap and plant hydraulic conductance increased 24 h after fertilization with KCl. The aim of this work was to test whether water-stressed laurel plants, grown under low potassium availability, could recover earlier from stress when irrigated with a KCl solution instead of potassium-fr…

Transpiration rates and hydraulic conductance of two olive genotypes with different sensitivity to drought

2019

Although some mechanisms of leaf dehydration tolerance are known in olive (Olea europaea L.), insights on adjustments in stem and root hydraulic conductance (K) in response to drought are yet to be explored. This work investigated transpiration mechanisms and K regulations in two olive genotypes showing different sensitivity to drought stress. In 2017, one-year-old potted ‘Nocellara del Belice’ (NB) and ‘Cerasuola’ (CE) plants were set in a greenhouse and double-bagged to avoid evaporation from soil surface. Half of the plants were drought-stressed (DS, no irrigation) for more than 30 days and the remaining plants were well-watered (WW). At the end of the drought period, stem and root porti…

Resistance simulations for junctions of SW and MW carbon nanotubes with various metal substrates

2011

Abstract This theoretical study focuses on junctions between the carbon nanotubes (CNTs) and contacting metallic elements of a nanocircuit. Numerical simulations on the conductance and resistance of these contacts have been performed using the multiple scattering theory and the effective media cluster approach. Two models for CNT-metal contacts have been considered in this paper: a) first principles “liquid metal” model and b) semi-empirical model of “effective bonds” based on Landauer notions on ballistic conductivity. Within the latter, which is a more adequate description of chirality effects, we have simulated both single-wall (SW) and multi-wall (MW) CNTs with different morphology. Res…