925 research outputs found
Status and prospects of the NEXT experiment for neutrinoless double beta decay searches
NEXT (Neutrino Experiment with a Xenon TPC) is an experimental program whose
goals are to discover neutrinoless double beta decay using Xe in high
pressure xenon TPCs with electroluminescent readout. In this paper, results
from the NEXT-White detector, which is currently taking data at Laboratorio
Subterr\'aneo de Canfranc (LSC) will be reported. The prospects for the
NEXT-100 apparatus, scheduled to start operations in 2020, as well as the plans
to extend the technology to large and ultra-low background detectors needed to
fully explore the inverse hierarchy of neutrino masses, will also be briefly
discussed.Comment: This article is an expanded version of my contribution to the 2019
EW/QCD/Gravitation session of the 54th "Rencontres de Moriond
A Fast and Precise Method To Identify Indolic Glucosinolates and Camalexin in Plants by Combining Mass Spectrometric and Biological Information
In this manuscript, a fast and accurate identification and quantitation by mass spectrometry of indolic
glucosinolates and camalexin involved in defense in Arabidopsis thaliana are described. Two elicitation systems, inoculation with
Botrytis cinerea and treatment with AgNO3, were used in Col-0 wild-type and mutant genotypes impaired in the biosynthesis of
the selected metabolites. Identification of analytes was carried out by nontargeted LC/ESI-QTOF-MS profiling. Confirmation of
indolic glucosinolates and camalexin was achieved by their absence in the cyp79B2/B3 and pad3 mutants as well as their
respective fragmentation upon collision-induced dissociation. Camalexin accumulation was induced only after AgNO3 treatment,
whereas all indolic glucosinolates were constitutively present. Inoculation with Botrytis did not influence camalexin concentration
but caused most aliphatic and indolic glucosinolates contents to decrease. Only the pen 3.1 mutant showed increased indolic
glucosinolate levels after Botrytis or AgNO3 treatments. In addition, profiles of secondary metabolite in nontreated Col-0 and
mutant plants were analyzed by means of partial least squares coupled to discriminant analysis (PLS-DA), and differences in the
basal levels of indolic glucosinolates and tryptophan between cyp79B2/B3 plants and the rest of genotypes, including Col-0, were
found. This probably has to be taken into consideration when comparing stress responses of Col-0 and cyp79B2/B3. The use of
mutants carrying alterations in biosynthetic pathways is proposed as a useful strategy to identify secondary metabolites
Metabolomics of Disease Resistance in Crops
Plants are continuously exposed to the attack of invasive microorganisms, such as fungi
or bacteria, and also viruses. To fight these attackers, plants develop different metabolic
and genetic responses whose final outcome is the production of toxic compounds that
kill the pathogen or deter its growth or semiotic molecules that alert other individuals of
the same plant species. These molecules are derived from the secondary metabolism and
their production is induced upon detection of a pathogen-associated molecular pattern
(PAMP). These PAMPs are different molecules that are perceived by the host cell
triggering defense responses. PAMP-elicited compounds are highly diverse and specific
of every plant species and can be divided into preformed metabolites or phytoanticipins
that are converted into toxic molecules upon pathogen perception, and toxic metabolites
or phytoalexins that are produced only upon pathogen attack. Moreover, plant volatile
emissions are also modified in response to pathogen attack to alert neighboring
individuals or to make plants less attractive to pathogen vector arthropods. Plant
metabolite profiling techniques have allowed the identification of novel antimicrobial
molecules that are induced upon elicitation. However, more studies are required to
assess the specific function of metabolites or metabolite blends on plant-microbe
interactions
Initial results from the HARP experiment at CERN
Initial results on particle yields obtained by the HARP experiment are
presented. The measurements correspond to proton--nucleus collisions at beam
energies of 12.9 and for a thin Al target of 5% interacion legth. The
angular range considered is between 10 and 250 . This results are the
first step in the upcoming measurement of the forward production cross-section
for the same target and beam energy, relevant for the calculation of the
far--to--near ratio of the K2K experiment.Comment: Presented at the Neutrino 2004 Internation Conferenc
Neutrinoless double-beta decay. A brief review
In this brief review we discuss the generation of Majorana neutrino masses
through the see-saw mechanism, the theory of neutrinoless double-beta decay,
the implications of neutrino oscillation data for the effective Majorana mass,
taking into account the recent Daya Bay measurement of theta_13, and the
interpretation of the results of neutrinoless double-beta decay experiments.Comment: 22 page
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