Eddy covariance and sap flow measurement of energy and mass exchanges of woody crops in a Mediterranean environment

Evapotranspiration estimation by micrometeorological techniques through the assessment of mass and energy exchanges in the soil-plant-atmosphere continuum (SPAC) is a very active research area, involving both well-known and novel measurement techniques. A crucial aspect in validating experimental results is the integration of independent measurements of mass and energy exchanges in the SPAC. To this aim, the development and validation of an integrated approach in major tree crop species, involving different independent techniques, are presented. Eddy covariance estimates of ET fluxes were compared to up-scaled sap flow measurements in olive, orange and grapevine, three important Mediterranean tree crop species with contrasting ecophysiological characteristics and responses to water deficits. These differences can affect directly the degree of coupling of the tree to the environment and, consequently, the degree of correspondence between instantaneous transpirational flux at tree level and the micrometeorological measurement of ET at orchard level. Data were analyzed to verify to what extent, in the three species, transpirational flow at orchard level is regulated by tree conductance, capacitance effects related to tree size or by environmental demand. Hourly observations were helpful in detecting physiological processes of the three species only when data were analyzed taking into consideration their diurnal changes

Comparison between methods for the determination of the primary cosmic ray mass composition from the longitudinal profile of atmospheric cascades

The determination of the primary cosmic ray mass composition from the longitudinal development of atmospheric cascades is still a debated issue. In this work we discuss several data analysis methods and show that if the entire information contained in the longitudinal profile is exploited, reliable results may be obtained. Among the proposed methods FCC ('Fit of the Cascade Curve'), MTA ('Multiparametric Topological Analysis') and NNA ('Neural Net Analysis') with conjugate gradient optimization algorithm give the best accuracy.Comment: 22 pages, 11 figures, accepted by Astroparticle Physics, minor misprints and an extra figure remove

Synthesis, biophysical characterization and anti-HIV activity of d(TG3AG) Quadruplexes bearing hydrophobic tails at the 5'-end

Novel conjugated G-quadruplex-forming d(TG3AG) oligonucleotides, linked to hydrophobic groups through phosphodiester bonds at 50-end, have been synthesized as potential anti-HIV aptamers, via a fully automated, online phosphoramidite-based solid-phase strategy. Conjugated quadruplexes showed pronounced anti-HIV activity with some preference for HIV-1, with inhibitory activity invariably in the low micromolar range. The CD and DSC monitored thermal denaturation studies on the resulting quadruplexes, indicated the insertion of lipophilic residue at the 50-end, conferring always improved stability to the quadruplex complex (20 < DTm < 40 C). The data suggest no direct functional relationship between the thermal stability and anti-HIV activity of the folded conjugated G-quartets. It would appear that the nature of the residue at 50 end of the d(TG3AG) quadruplexes plays an important role in the thermodynamic stabilization but a minor influence on the anti-HIV activity. Moreover, a detailed CD and DSC analyses indicate a monophasic behaviour for sequences I and V, while for ODNs (II–IV) clearly show that these quadruplex structures deviate from simple two-state melting, supporting the hypothesis that intermediate states along the dissociation pathway may exis

Atmospheric effects on extensive air showers observed with the Surface Detector of the Pierre Auger Observatory

Atmospheric parameters, such as pressure (P), temperature (T) and density, affect the development of extensive air showers initiated by energetic cosmic rays. We have studied the impact of atmospheric variations on extensive air showers by means of the surface detector of the Pierre Auger Observatory. The rate of events shows a ~10% seasonal modulation and ~2% diurnal one. We find that the observed behaviour is explained by a model including the effects associated with the variations of pressure and density. The former affects the longitudinal development of air showers while the latter influences the Moliere radius and hence the lateral distribution of the shower particles. The model is validated with full simulations of extensive air showers using atmospheric profiles measured at the site of the Pierre Auger Observatory.Comment: 24 pages, 9 figures, accepted for publication in Astroparticle Physic

Measurement of the Depth of Maximum of Extensive Air Showers above 10^18 eV

We describe the measurement of the depth of maximum, Xmax, of the longitudinal development of air showers induced by cosmic rays. Almost four thousand events above 10^18 eV observed by the fluorescence detector of the Pierre Auger Observatory in coincidence with at least one surface detector station are selected for the analysis. The average shower maximum was found to evolve with energy at a rate of (106 +35/-21) g/cm^2/decade below 10^(18.24 +/- 0.05) eV and (24 +/- 3) g/cm^2/decade above this energy. The measured shower-to-shower fluctuations decrease from about 55 to 26 g/cm^2. The interpretation of these results in terms of the cosmic ray mass composition is briefly discussed.Comment: Accepted for publication by PR

The Fluorescence Detector of the Pierre Auger Observatory

The Pierre Auger Observatory is a hybrid detector for ultra-high energy cosmic rays. It combines a surface array to measure secondary particles at ground level together with a fluorescence detector to measure the development of air showers in the atmosphere above the array. The fluorescence detector comprises 24 large telescopes specialized for measuring the nitrogen fluorescence caused by charged particles of cosmic ray air showers. In this paper we describe the components of the fluorescence detector including its optical system, the design of the camera, the electronics, and the systems for relative and absolute calibration. We also discuss the operation and the monitoring of the detector. Finally, we evaluate the detector performance and precision of shower reconstructions.Comment: 53 pages. Submitted to Nuclear Instruments and Methods in Physics Research Section

Search for First Harmonic Modulation in the Right Ascension Distribution of Cosmic Rays Detected at the Pierre Auger Observatory

We present the results of searches for dipolar-type anisotropies in different energy ranges above $2.5\times 10^{17}$ eV with the surface detector array of the Pierre Auger Observatory, reporting on both the phase and the amplitude measurements of the first harmonic modulation in the right-ascension distribution. Upper limits on the amplitudes are obtained, which provide the most stringent bounds at present, being below 2% at 99% $C.L.$ for EeV energies. We also compare our results to those of previous experiments as well as with some theoretical expectations.Comment: 28 pages, 11 figure

Fetal propofol and dexmedetomidine exposure during elective c-section in the bitch: impact on pup viability

Elective C-section is a common procedure recommended in dogs at risk of dystocia(1). Anesthetics administered at surgery can cross the placenta leading to distress up to neonatal mortality(2). The study aims to determine the impact on pup viability of a new anesthetic-analgesic protocol for elective C-section in the bitch. For this purpose, propofol (PPF) and dexmedetomidine (DEX) concentrations in maternal blood, amniotic fluid and placental tissue were correlate to neonatal parameters. Nine purebred bitches (age 4,9±2,3 years; weight 39,8±10,4 kg) were induced with a combination of PPF at 2,5 mg/kg and DEX at 2 μg/kg IV and maintained with isoflurane in 100% oxygen for elective C-section. If needed, additional doses of PPF were administered to effect in order to achieve intubation of patients. DEX and PPF quantification from the different biological matrices was carried out by HPLC-MS and HPLC-FL methods. Neonatal viability at birth was assessed with a modified Apgar score(3) (AS) and birth weight recorded as well as mortality of pups within 48 hours of life. Results: A total of 54 pups was delivered, 77,80% of them recorded as vigorous by AS. Neonatal mortality was 11,1%. Lowest AS was assigned to pups from mothers receiving additional dose of PPF. AS was not influenced by birth weight of pups, nor by maternal and placental drugs concentrations. Maternal blood PPF (range 0,24-2,8- mcg/mL) and DEX (range 0,41-2,04 ng/mL), and placental PPF (range 0,24-2,57 mcg/mL) concentrations tended to decrease over time, while placental DEX (range 1,32-6,15 ng/mL) was fairly uniformly detected in pups from the same litter. DEX concentration in placenta was much higher than in maternal blood showing a greater placental retention compared with PPF. Both PPF and DEX were not detectable in amniotic fluid. Placenta resulted an effective barrier against fetal DEX exposure making this protocol safe, analgesic and advisable for elective C-section in dog. (1) Moon PF, Erb HN, Ludders JW, et al. Perioperative Risk Factors for Puppies Delivered by Cesarean Section in the United States and Canada. J Am Anim Hosp Assoc 2000;36:359-68. (2) Luna SPL, Cassu RN, Castro GB et al. Effects of four anaesthetic protocols on the neurological and cardiorespiratory variables of puppies born by caesarean section. Vet Rec 2004;154:387–89 (3) Groppetti D, Pecile A, Del Carro AP, et al. Evaluation of newborn canine viability by means of umbilical vein lactate measurement, apgar score and uterine tocodynamometry. Theriogenology 2010;74(7):1187-96