8,597 research outputs found
On a possible EPR experiment with pairs
A very general local realistic theory of single mesons and of
correlated pairs is formulated. If these pairs are
produced in the decay, the local realistic asymmetry for
observing pairs with like and unlike flavour at different proper times
remarkably differs from the quantum mechanical prediction. Asymmetric
B-factories provide a powerful tool for the study of the EPR problem since the
relative detection experiments are shown to be capable of a time-dependent
measurement precise enough to discriminate between local realism and quantum
theory.Comment: 18 pages, 3 figure
Effects of long term application of compost and poultry manure on soil quality of citrus orchards in Southern Italy.
A six-year study was carried out in an organically managed orange orchard located in Sicily (Southern Italy) to assess the effect of compost and organic fertilizers utilisation on soil quality. Adopting a randomized-block experimental design with three replicates, four treatments were carried out. In treatments 1 and 2, two different composts (C1 from distillery by products and C2 from livestock wastes) were applied. The plots of treatment 3 were fertilized using dried poultry manure. The control treatment was fertilized with mineral/synthetic fertilizers. In order to verify the hypothesis that composts and organic fertilizers improve soil fertility, soil quality was evaluated by selecting dynamic soil parameters, as indicators linked to C and N cycles. Total organic C, total N, C/N ratio, humified fraction, isoelectric focusing (IEF) of extracted organic matter, microbial biomass C, potentially mineralisable N under anaerobic conditions, potenzially mineralizable C, C mineralization quotient and metabolic quotient were determined for each sample. Furthermore, the Comunity level Physiological Profile (by Biolog tecnique) was defined, calculating derived functional biodiversity and versatility indexes. Parameters related to IEF and potentially mineralizable C showed significant differences among the treatments. Moreover, total C, total N and humification parameters tended to increase, while no differences were observed in biodiversity indexes. On these findings, it was concluded that composts and poultry manure only weakly affected soil properties, though they increased soil nutritive elements potentially available to crops
Characterization of self-injected electron beams from LWFA experiments at SPARC_LAB
The plasma-based acceleration is an encouraging technique to overcome the
limits of the accelerating gradient in the conventional RF acceleration. A
plasma accelerator is able to provide accelerating fields up to hundreds of
, paving the way to accelerate particles to several MeV over a short
distance (below the millimetre range). Here the characteristics of preliminary
electron beams obtained with the self-injection mechanism produced with the
FLAME high-power laser at the SPARC_LAB test facility are shown. In detail,
with an energy laser on focus of and a pulse temporal length (FWHM) of
, we obtained an electron plasma density due to laser ionization of
about , electron energy up to and beam
charge in the range .Comment: 6 pages, 11 figures, conference EAAC201
Impairment of the autophagic flux in astrocytes intoxicated by trimethyltin
Autophagy is a lysosomal catabolic route for protein aggregates and damaged organelles which in different stress conditions, such as starvation, generally improves cell survival. An impairment of this degradation pathway has been reported to occur in many neurodegenerative processes. Trimethyltin (TMT) is a potent neurotoxin present as an environmental contaminant causing tremors, seizures and learning impairment in intoxicated subjects. The present data show that in rat primary astrocytes autophagic vesicles (AVs) appeared after few hours of TMT treatment. The analysis of the autophagic flux in TMT-treated astrocytes was consistent with a block of the late stages of autophagy and was accompanied by a progressive accumulation of the microtubule associated protein light chain 3 (LC3) and of p62/SQSTM1. Interestingly, an increased immunoreactivity for p62/SQSTM1 was also observed in hippocampal astrocytes detected in brain slices of TMT-intoxicated rats. The time-lapse recordings of AVs in EGFP-mCherry-LC3B transfected astrocytes demonstrated a reduced mobility of autophagosomes after TMT exposure respect to control cells. The observed block of the autophagic flux cannot be overcome by known autophagy inducers such as rapamycin or 0.5mM lithium. Although ineffective when used at 0.5mM, lithium at higher concentrations (2mM) was able to protect astrocyte cultures from TMT toxicity. This effect correlated well with its ability to determine the phosphorylation/inactivation of glycogen kinase synthase-3β (GSK-3β)
Autophagy in trimethyltin-induced neurodegeneration
Autophagy is a degradative process playing an important role in removing misfolded or aggregated proteins, clearing damaged organelles, such as mitochondria and endoplasmic reticulum, as well as eliminating intracellular pathogens. The autophagic process is important for balancing sources of energy at critical developmental stages and in response to nutrient stress. Recently, autophagy has been involved in the pathophysiology of neurodegenerative diseases although its beneficial (pro-survival) or detrimental (pro-death) role remains controversial. In the present review, we discuss the role of autophagy following intoxication with trimethyltin (TMT), an organotin compound that induces severe hippocampal neurodegeneration associated with astrocyte and microglia activation. TMT is considered a useful tool to study the molecular mechanisms occurring in human neurodegenerative diseases such as Alzheimer’s disease and temporal lobe epilepsy. This is also relevant in the field of environmental safety, since organotin compounds are used as heat stabilizers in polyvinyl chloride polymers, industrial and agricultural biocides, and as industrial chemical catalysts
Neutron spectrometer for fast nuclear reactors
In this paper we describe the development and first tests of a neutron
spectrometer designed for high flux environments, such as the ones found in
fast nuclear reactors. The spectrometer is based on the conversion of neutrons
impinging on Li into and whose total energy comprises the
initial neutron energy and the reaction -value. The LiF layer is
sandwiched between two CVD diamond detectors, which measure the two reaction
products in coincidence. The spectrometer was calibrated at two neutron
energies in well known thermal and 3 MeV neutron fluxes. The measured neutron
detection efficiency varies from 4.2 to 3.5 for
thermal and 3 MeV neutrons, respectively. These values are in agreement with
Geant4 simulations and close to simple estimates based on the knowledge of the
Li(n,) cross section. The energy resolution of the spectrometer
was found to be better than 100 keV when using 5 m cables between the detector
and the preamplifiers.Comment: submitted to NI
O070. The association between temperament, depression, hopelessness and quality of life in medication-overuse headache patients
No abstract availabl
Conceptual design of electron beam diagnostics for high brightness plasma accelerator
A design study of the diagnostics of a high brightness linac, based on X-band
structures, and a plasma accelerator stage, has been delivered in the framework
of the EuPRAXIA@SPARC_LAB project. In this paper, we present a conceptual
design of the proposed diagnostics, using state of the art systems and new and
under development devices. Single shot measurements are preferable for plasma
accelerated beams, including emittance, while m level and fs scale beam
size and bunch length respectively are requested. The needed to separate the
driver pulse (both laser or beam) from the witness accelerated bunch imposes
additional constrains for the diagnostics. We plan to use betatron radiation
for the emittance measurement just at the end of the plasma booster, while
other single-shot methods must be proven before to be implemented. Longitudinal
measurements, being in any case not trivial for the fs level bunch length, seem
to have already a wider range of possibilities
Frontiers of beam diagnostics in plasma accelerators: measuring the ultra-fast and ultra-cold
Advanced diagnostics are essential tools in the development of plasma-based accelerators. The accurate measurement of the quality of beams at the exit of the plasma channel is crucial to optimize the parameters of the plasma accelerator. 6D electron beam diagnostics will be reviewed with emphasis on emittance measurement, which is particularly complex due to large energy spread and divergence of the emerging beams, and on femtosecond bunch length measurements
Intense terahertz pulses from SPARC-LAB coherent radiation source
The linac-based Terahertz source at the SPARC_LAB test facility is able to gene
rate highly intense Terahertz broadband
pulses
via
coherent transition radiation (CTR) from high brightness electron beams. The THz pulse duration is typically
down to 100 fs RMS and can be tuned through the electron bunch duration and shaping. The measured stored energy in a
single THz pulse has reached 40
μ
J, which corresponds to a peak
electric field of 1.6 MV/cm at the THz focus. Here we
present the main features, in particular spatial and sp
ectral distributions and energy
characterizations of the
SPARC_LAB THz source, which is very competitive for investigations in Condensed Matter, as well as a valid tool for
electron beam longitudinal diagnostics
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