383 research outputs found
Fomitiporia mediterranea Infecting Citrus Trees in Greece
In recent years a serious disease of citrus (the orange cv. Washington navel, lemon and the common
mandarin grafted on sour orange rootstocks) has been observed in southern Greek orchards. Affected trees decline,
their leaves become yellow and fall early, and shoots and twigs die as the damage expands towards the trunk. Crosssections
of the trunks and large branches reveal a light-colored rot in the center, which is surrounded by brown hard
necrotic wood. Symptoms start from pruned areas and spread to the rootstock wood, and then resemble esca of
grapevine. From the white rotted areas, a fungus was isolated on PDA that formed cream-yellow to light-brown
colonies with dense aerial mycelium. Fungal fruit-bodies formed abundantly on the trunks of diseased trees. The
fungus was identified as Fomitiporia mediterranea by both traditional and molecular methods. Pathogenicity tests
were performed by artificially inoculating orange, mandarin, lemon and sour orange trees with the fungus. Control
holes were filled with two PDA plugs. Branches inoculated with the isolates from infected citrus showed wood discoloration
that extended up to 20 cm above and 20 cm below the infection hole. The fungus was re-isolated from the
discolored parts of the wood. Inoculations with isolates from grapevine and kiwi produced wood discoloration only 3–
4 mm around the holes
NELIOTA: The wide-field, high-cadence lunar monitoring system at the prime focus of the Kryoneri telescope
We present the technical specifications and first results of the ESA-funded,
lunar monitoring project "NELIOTA" (NEO Lunar Impacts and Optical TrAnsients)
at the National Observatory of Athens, which aims to determine the
size-frequency distribution of small Near-Earth Objects (NEOs) via detection of
impact flashes on the surface of the Moon. For the purposes of this project a
twin camera instrument was specially designed and installed at the 1.2 m
Kryoneri telescope utilizing the fast-frame capabilities of scientific
Complementary Metal-Oxide Semiconductor detectors (sCMOS). The system provides
a wide field-of-view (17.0' 14.4') and simultaneous observations in
two photometric bands (R and I), reaching limiting magnitudes of 18.7 mag in 10
sec in both bands at a 2.5 signal-to-noise level. This makes it a unique
instrument that can be used for the detection of NEO impacts on the Moon, as
well as for any astronomy projects that demand high-cadence multicolor
observations. The wide field-of-view ensures that a large portion of the Moon
is observed, while the simultaneous, high-cadence, monitoring in two
photometric bands makes possible, for the first time, the determination of the
temperatures of the impacts on the Moon's surface and the validation of the
impact flashes from a single site. Considering the varying background level on
the Moon's surface we demonstrate that the NELIOTA system can detect NEO impact
flashes at a 2.5 signal-to-noise level of ~12.4 mag in the I-band and R-band
for observations made at low lunar phases ~0.1. We report 31 NEO impact flashes
detected during the first year of the NELIOTA campaign. The faintest flash was
at 11.24 mag in the R-band (about two magnitudes fainter than ever observed
before) at lunar phase 0.32. Our observations suggest a detection rate of events .Comment: Accepted for publication in A&
Dipstick proteinuria is an independent predictor of high on treatment platelet reactivity in patients on clopidogrel, but not aspirin, admitted for major adverse cardiovascular events.
Abstract The effectiveness of aspirin and clopidogrel in patients with chronic kidney disease (CKD) suffering from acute cardiovascular events is unclear. High on treatment platelet reactivity (HTPR) has been associated with worse outcomes. Here, we assessed the association of dipstick proteinuria (DP) and renal function on HTPR and clinical outcomes. Retrospective cohort analysis of 261 consecutive, non-dialysis patients admitted for Major Adverse Cardiovascular Events (MACE) that had VerifyNow P2Y12 and VerifyNow Aspirin assays performed. HTPR was defined as P2Y12 reactivity unit (PRU) \u3e 208 for clopidogrel and aspirin reaction units (ARU) \u3e 550 for aspirin. Renal function was classified based on the estimated glomerular filtration rate (eGFR), and dipstick proteinuria was defined as ≥30 mg/dl of albumin detected on a spot analysis. All cause mortality, readmissions, and cardiac catheterizations were reviewed over 520 days. In patients on clopidogrel (n = 106), DP was associated with HTPR, independent of eGFR, diabetes mellitus, smoking or use of proton pump inhibitor (AOR = 4.76, p = 0.03). In patients with acute coronary syndromes, HTPR was associated with more cardiac catheterizations (p = 0.009) and readmissions (p = 0.032), but no differences in in-stent thrombosis or re-stenosis were noted in this cohort. In patients on aspirin (n = 155), no associations were seen between DP and HTPR. However, all cause mortality was significantly higher with HTPR in this group (p = 0.038). In this cohort, DP is an independent predictor of HTPR in patients on clopidogrel, but not aspirin, admitted to the hospital for MACE
On the absence of bound-state stabilization through short ultra-intense fields
We address the question of whether atomic bound states begin to stabilize in
the short ultra-intense field limit. We provide a general theory of ionization
probability and investigate its gauge invariance. For a wide range of
potentials we find an upper and lower bound by non-perturbative methods, which
clearly exclude the possibility that the ultra intense field might have a
stabilizing effect on the atom. For short pulses we find almost complete
ionization as the field strength increases.Comment: 34 pages Late
On the Influence of Pulse Shapes on Ionization Probability
We investigate analytical expressions for the upper and lower bounds for the
ionization probability through ultra-intense shortly pulsed laser radiation. We
take several different pulse shapes into account, including in particular those
with a smooth adiabatic turn-on and turn-off. For all situations for which our
bounds are applicable we do not find any evidence for bound-state
stabilization.Comment: 21 pages LateX, 10 figure
Multiphoton detachment of electrons from negative ions
A simple analytical solution for the problem of multiphoton detachment from
negative ions by a linearly polarized laser field is found. It is valid in the
wide range of intensities and frequencies of the field, from the perturbation
theory to the tunneling regime, and is applicable to the excess-photon as well
as near-threshold detachment. Practically, the formulae are valid when the
number of photons is greater than two. They produce the total detachment rates,
relative intensities of the excess-photon peaks, and photoelectron angular
distributions for the hydrogen and halogen negative ions, in agreement with
those obtained in other, more numerically involved calculations in both
perturbative and non-perturbative regimes. Our approach explains the extreme
sensitivity of the multiphoton detachment probability to the asymptotic
behaviour of the bound-state wave function. Rapid oscillations in the angular
dependence of the -photon detachment probability are shown to arise due to
interference of the two classical trajectories which lead to the same final
state after the electron emerges at the opposite sides of the atom when the
field is close to maximal.Comment: 27 pages, Latex, and PostScript figures fig1.ps, fig2.ps, fig3.ps,
accepted for publication in Phys. Rev.
Ionization Probabilities through ultra-intense Fields in the extreme Limit
We continue our investigation concerning the question of whether atomic bound
states begin to stabilize in the ultra-intense field limit. The pulses
considered are essentially arbitrary, but we distinguish between three
situations. First the total classical momentum transfer is non-vanishing,
second not both the total classical momentum transfer and the total classical
displacement are vanishing together with the requirement that the potential has
a finite number of bound states and third both the total classical momentum
transfer and the total classical displacement are vanishing. For the first two
cases we rigorously prove, that the ionization probability tends to one when
the amplitude of the pulse tends to infinity and the pulse shape remains fixed.
In the third case the limit is strictly smaller than one. This case is also
related to the high frequency limit considered by Gavrila et al.Comment: 16 pages LateX, 2 figure
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