5,088 research outputs found
Electromagnetic properties of doubly charmed baryons in Lattice QCD
We compute the electromagnetic properties of \Xi_cc baryons in 2+1 flavor
Lattice QCD. By measuring the electric charge and magnetic form factors of
\Xi_cc baryons, we extract the magnetic moments, charge and magnetic radii as
well as the \Xi_cc \Xi_cc \rho coupling constant, which provide important
information to understand the size, shape and couplings of the doubly charmed
baryons. We find that the two heavy charm quarks drive the charge radii and the
magnetic moment of \Xi_cc to smaller values as compared to those of, e.g., the
proton.Comment: 15 pages, 5 figures; added discussions and references, version
accepted by PL
Electromagnetic structure of charmed baryons in Lattice QCD
As a continuation of our recent work on the electromagnetic properties of the
doubly charmed baryon, we compute the charge radii and the magnetic
moments of the singly charmed , and the doubly charmed
baryons in 2+1 flavor Lattice QCD. In general, the charmed
baryons are found to be compact as compared to the proton. The charm quark acts
to decrease the size of the baryons to smaller values. We discuss the mechanism
behind the dependence of the charge radii on the light valence- and sea-quark
masses. The magnetic moments are found to be almost stable with respect to
changing quark mass. We investigate the individual quark sector contributions
to the charge radii and the magnetic moments. The magnetic moments of the
singly charmed baryons are found to be dominantly determined by the light quark
and the role of the charm quark is significantly enhanced for the doubly
charmed baryons.Comment: Updated results, improved analysis. Version to appear in JHE
Measurement of the differential dijet production cross section in proton-proton collisions at \sqrt{s} = 7 tev
A measurement of the double-differential inclusive dijet production cross
section in proton-proton collisions at \sqrt{s}= 7 TeV is presented as a
function of the dijet invariant mass and jet rapidity. The data correspond to
an integrated luminosity of 36 pb^{-1}, recorded with the CMS detector at the
LHC in 2010. The measurement covers the dijet mass range 0.2 TeV to 3.5 TeV and
jet rapidities up to |y|=2.5. It is found to be in good agreement with
next-to-leading-order QCD predictions.Comment: ph.d. Thesi
Distinguishing between recent balancing selection and incomplete sweep using deep neural networks
Balancing selection is an important adaptive mechanism underpinning a wide range of phenotypes. Despite its relevance, the detection of recent balancing selection from genomic data is challenging as its signatures are qualitatively similar to those left by ongoing positive selection. In this study, we developed and implemented two deep neural networks and tested their performance to predict loci under recent selection, either due to balancing selection or incomplete sweep, from population genomic data. Specifically, we generated forward-in-time simulations to train and test an artificial neural network (ANN) and a convolutional neural network (CNN). ANN received as input multiple summary statistics calculated on the locus of interest, while CNN was applied directly on the matrix of haplotypes. We found that both architectures have high accuracy to identify loci under recent selection. CNN generally outperformed ANN to distinguish between signals of balancing selection and incomplete sweep and was less affected by incorrect training data. We deployed both trained networks on neutral genomic regions in European populations and demonstrated a lower false-positive rate for CNN than ANN. We finally deployed CNN within the MEFV gene region and identified several common variants predicted to be under incomplete sweep in a European population. Notably, two of these variants are functional changes and could modulate susceptibility to familial Mediterranean fever, possibly as a consequence of past adaptation to pathogens. In conclusion, deep neural networks were able to characterize signals of selection on intermediate frequency variants, an analysis currently inaccessible by commonly used strategies
Temporal changes in the gene expression heterogeneity during brain development and aging
Cells in largely non-mitotic tissues such as the brain are prone to stochastic (epi-)genetic alterations that may cause increased variability between cells and individuals over time. Although increased interindividual heterogeneity in gene expression was previously reported, whether this process starts during development or if it is restricted to the aging period has not yet been studied. The regulatory dynamics and functional significance of putative aging-related heterogeneity are also unknown. Here we address these by a meta-analysis of 19 transcriptome datasets from three independent studies, covering diverse human brain regions. We observed a significant increase in inter-individual heterogeneity during aging (20 + years) compared to postnatal development (0 to 20 years). Increased heterogeneity during aging was consistent among different brain regions at the gene level and associated with lifespan regulation and neuronal functions. Overall, our results show that increased expression heterogeneity is a characteristic of aging human brain, and may influence aging-related changes in brain functions
Ion selective electrodes in ion chromatography
PhD ThesisThe number of applications of potentiometric detection In Ion
chromatography Is Increasing In the use of ion selective electrodes
for which the response Is not limited to a few number of Ions.
In this research, membrane electrodes, for a number of Ions, based
on PVC were prepared to examine selectivity, detection limit and
reproducibility for chromatographic and flow-injection measurements
via mixed solution method and flow-injection technique. The
selectivity sequence of anion selective electrodes for single
charged Inorganic anions was F< Cl < Br < NO
2<
NO
3<I.
This was
Ll +< Nil+< Cs+< Na+< K+ for cation selective electrodes. The
4
detection limits for most of anions and cations were found to be at
the nanogram or picogram levels.
Response times of bromide and chloride electrodes were established
to concentration and flow-rate changes in a flowing stream. When
flow-rate was Increased, response time of electrode decreased, but
response volume Increased. Response time was decreased for low
activities rather than high activities of solute ion when flow-rate
Increased. At high flow-rates, response time was Independent of
the activity of the solute Ion. Also a new approach to the
definition of the response time in flowing conditions was purposed
In order to be able to Indicate their performances.
An evaluation of the Influence and contribution of the sample
dispersion on the sensitivity of tubular liquid membrane bromide
selective electrode based on PVC was examined with a new, easy
reliable approach In a flow-injection system for chromatographic
measurements. Using water as carrier, it was observed that the
dispersion Influence was completely dependent on the response time
of electrodes. When sample In the carrier passes through the
electrode surface just within the electrode response time, better
peak shape and sensitivity were obtained at each flow-rate, whilst
shorter remaining time of sample caused tailing and decreasing of
the sensitivity, longer remaining time caused peak broadening.
An all solid-state tubular PVC-matrix membrane electrode as
detector In non-suppressed Ion chromatography was employed Jor
detection of some monovalent common anions Including I and SO at
sub-ppb levels. Non-supprýessed separation of halides and strongly
retained anions I and SCN In one run was achieved using Phosphate
solution as a new efficient eluent over Dionex IonPac-AS4A and AG4A
columns. Potentlometric detection of eleven monovalent Inorganic
and organic anions with the use of all solid-state contact tubular
membrane electrode (cell volume 2 pl) as detector In non-suppressed
Ion chromatography was demonstrated using phosphate and hydrogen
phosphate as eluents at low concentrations. Theoretical and
practical considerations were discussed, and In particular,
sensitivity, linearity, detection limit and dynamic behaviour were
presented. Applications to river, drinking and rain water samples
were described.
In any liquid chromatographic technique, the eluent composition
provides greatest flexibility for manipulating the retention of
solutes In order to achieve a desired separation. Utilizations of
a new composition of the 11CO
3
/CO
32
buffer solution or phosphate
solution as eluents were demonstrated for the separation of twelve
Inorganic and organic anions with good resolution in six minutes
using Dionex-100 ion chromatographic system.
A simple and selective method for single Ion chromatographic
11
separation (in seven mlnVtesý and potentiom+etric detection (at
sub-ppb levels) of Na"', Nil
4,
K. Rb +0 THA +0 Cs and Tl+ cations was
established using copper and magnesium salts as eluents, with
Dionex IonPac-CS3 analytical and guard columns and all solid-state
contact tubular membrane potassium selective electrode as detector.
The application of the method for drinking, river, spring, sea
water samples and orange juice, urine and saliva samples were
illustrated. As the detector was highly selective and sensitive to
only monovalent cations, no Interference from other cations, the
method was easily applIjd to mjny sample types examples Including
the determination of Na and K, on the surface of the glassware
adsorbed during the fabrication stage, and In many inorganic and
organic chemicals were given.
It might be the over-all efficiency of Ion chromatographic
procedures that allows the routine separation and detection of
Inorganic and organic anions and cations at low levels in a
simultaneous system. A simple, selective, sensitive reproducible
and rapid method needing only 8 minutes or less to complete a
simultaneous potentiometric detection and Independent separation of
a group of fourteen Inorganic and organic monovalent common anions
and cations was developed using copper or magnesium sulphate salt
as eluents with Dionex 1onPac-AS4A and -CS3 anion and
cation-exchange columns In tandem. The only difference of the
method from other simple chromatographic applications was just one
more chromatographic column and one more potentiometric detector.
The method was flexible, as the anions will not Interfere with the
detection of cations or cations will not Interfere with the
detection of anions, that detectors can be used at the end of the
two column In tandem or one can be used af ter f Irst column. The
first column can be anion or cation-exchange.
A method for simultaneous determination of sodium, potassium and
chloride In bovine serum albumin plasma was established. it
Involved Independent Ion chromatographic separation on anion and
cation- exchange columns and simultaneous potentiometric detection
by anion and cation selective electrodes. The concentrations of
monovalent cations and chloride was Increased with the Increasing
of dilution of non-filtered sample, there was no significant
changes In the concentrations determined In the sample which was
filtered
A hypokalemic muscular weakness after licorice ingestion: a case report
A 21-year-old male presented to the emergency department with the complaint of muscle weakness. The patient had used a powderized over-the-counter product named 'Tekumut' for 2 weeks to quit smoking. The granulated product was studied and determined to contain 'licorice' containing glycyrrhizic acid
The aetiopathologies of Ménières disease: a contemporary review
La Sindrome di Ménière, una condizione descritta nel 1800, è stata unarea di grande interesse clinico e di ricerca scientifica negli ultimi decenni. Le linee guida pubblicate dall American Academy of Otolaryngology-Head and Neck Surgery sono rimaste pressoché invariate per quasi 20 anni, benché la ricerca scientifica sugli aspetti eziopatologici sia indubbiamente molto progredita nel frattempo. La presente revisione della letteratura evidenzia gli importanti progressi compiuti nella comprensione della fisiopatologia di questa malattia enigmatica. Le evidenze discusse sono inoltre accompagnate da una documentazione iconografica istopatologica. Lobiettivo della presente trattazione è fornire al lettore un quadro aggiornato ed accurato sulle teorie inerenti la Sindrome di Ménière
- …