3,293 research outputs found
A Finite Exact Representation of Register Automata Configurations
A register automaton is a finite automaton with finitely many registers
ranging from an infinite alphabet. Since the valuations of registers are
infinite, there are infinitely many configurations. We describe a technique to
classify infinite register automata configurations into finitely many exact
representative configurations. Using the finitary representation, we give an
algorithm solving the reachability problem for register automata. We moreover
define a computation tree logic for register automata and solve its model
checking problem.Comment: In Proceedings INFINITY 2013, arXiv:1402.661
GM-CSF Inhibits c-Kit and SCF Expression by Bone Marrow-Derived Dendritic Cells.
Stem cell factor (SCF), the ligand of c-kit, is a key cytokine for hematopoiesis. Hematopoietic precursors express c-kit, whereas differentiated cells of hematopoietic lineage are negative for this receptor, with the exception of NK cells, mast cells, and a few others. While it has long been recognized that dendritic cells (DCs) can express c-kit, several questions remain concerning the SCF/c-kit axis in DCs. This is particularly relevant for DCs found in those organs wherein SCF is highly expressed, including the bone marrow (BM). We characterized c-kit expression by conventional DCs (cDCs) from BM and demonstrated a higher proportion of c-kit+ cells among type 1 cDC subsets (cDC1s) than type 2 cDC subsets (cDC2s) in both humans and mice, whereas similar levels of c-kit expression were observed in cDC1s and cDC2s from mouse spleen. To further study c-kit regulation, DCs were generated with granulocyte-macrophage colony-stimulating factor (GM-CSF) from mouse BM, a widely used protocol. CD11c+ cells were purified from pooled non-adherent and slightly adherent cells collected after 7 days of culture, thus obtaining highly purified BM-derived DCs (BMdDCs). BMdDCs contained a small fraction of c-kit+ cells, and by replating them for 2 days with GM-CSF, we obtained a homogeneous population of c-kit+ CD40hi MHCIIhi cells. Not only did BMdDCs express c-kit but they also produced SCF, and both were striking upregulated if GM-CSF was omitted after replating. Furthermore, a small but significant reduction in BMdDC survival was observed upon SCF silencing. Incubation of BMdDCs with SCF did not modulate antigen presentation ability of these cells, nor it did regulate their membrane expression of the chemokine receptor CXCR4. We conclude that the SCF/c-kit-mediated prosurvival circuit may have been overlooked because of the prominent use of GM-CSF in DC cultures in vitro, including those human DC cultures destined for the clinics. We speculate that DCs more prominently rely on SCF in vivo in some microenvironments, with potential implications for graft-versus-host disease and antitumor immunity
A copula-based clustering algorithm to analyse EU country diets
The aim of the paper is to suggest a novel clustering technique to explore
the changes of the food diet in 40 European countries in accordance with
common European policies and guidelines on healthy diets and lifestyles.
The proposed clustering algorithm is based on copulas and it is called Co-
Clust. The CoClust algorithm is able to find clusters according to the mul-
tivariate dependence structure of the data generating process. The database
analysed contains information on the proportions of calories from 16 food
aggregates in 40 European countries observed over 40 years by the Food and
Agriculture Organization of the United Nations (FAO). The findings suggest
that European country diets are changing, individually or as a group, but not
in a unique direction. Central and Eastern European countries are becoming
unhealthier, while the tendency followed by the majority of the remaining
countries is to integrate the common European guidelines on healthy, bal-
anced, and diversified diets in their national policies
A comprehensive suite of earthquake catalogues for the 2016-2017 Central Italy seismic sequence
The protracted nature of the 2016-2017 central Italy seismic sequence, with multiple damaging earthquakes spaced over months, presented serious challenges for the duty seismologists and emergency managers as they assimilated the growing sequence to advise the local population. Uncertainty concerning where and when it was safe to occupy vulnerable structures highlighted the need for timely delivery of scientifically based understanding of the evolving hazard and risk. Seismic hazard assessment during complex sequences depends critically on up-to-date earthquake catalogues—i.e., data on locations, magnitudes, and activity of earthquakes—to characterize the ongoing seismicity and fuel earthquake forecasting models. Here we document six earthquake catalogues of this sequence that were developed using a variety of methods. The catalogues possess different levels of resolution and completeness resulting from progressive enhancements in the data availability, detection sensitivity, and hypocentral location accuracy. The catalogues range from real-time to advanced machine-learning procedures and highlight both the promises as well as the challenges of implementing advanced workflows in an operational environment
Pharmacological Proprieties of the Ethanol Extract of Muehlenbeckia platyclada (F. Muell.) Meisn. Leaves
Antinociceptive and anti-inflammatory activities of the Muehlenbeckia platyclada leaves’ ethanol extract were investigated in animal models. The extract (p.o.) reduced the number of abdominal contortions induced by acetic acid by 21.57% (400 mg/kg). After intraplantar injection of formalin, a dose of 400 mg/kg (p.o.) inhibited the time spent paw licking in the first phase (26.43%), while the second phase was inhibited by 10.90 and 36.65% at the doses of 200 and 400 mg/kg, respectively. The extract (p.o.) increased the reaction time on a hot plate at a dose of 400 mg/kg (32.68 and 40.30%) after 60 and 90 minutes of treatment, respectively. The paw edema was reduced by extract (p.o.) at doses of 100 (15.46 and 16.67%), 200 (22.68 and 25.64%) and 400 mg/kg (29.50 and 37.33%) after 3 to 4 h of carrageenan application, respectively. Doses of 100, 200 and 400 mg/kg (p.o.), administered 4 h after the carrageenan injection, reduced the exudate volume (11.28, 21.54 and 45.13%), while leukocyte migration was reduced by 21.21 and 29.70% at the doses of 200 and 400 mg/kg, respectively. These results indicate that the ethanol extract from M. platyclada may constitute a potential target for the discovery of new molecules with antinociceptive and anti-inflammatory activities that can be explored for their therapeutic use
Transverse-target-spin asymmetry in exclusive -meson electroproduction
Hard exclusive electroproduction of mesons is studied with the
HERMES spectrometer at the DESY laboratory by scattering 27.6 GeV positron and
electron beams off a transversely polarized hydrogen target. The amplitudes of
five azimuthal modulations of the single-spin asymmetry of the cross section
with respect to the transverse proton polarization are measured. They are
determined in the entire kinematic region as well as for two bins in photon
virtuality and momentum transfer to the nucleon. Also, a separation of
asymmetry amplitudes into longitudinal and transverse components is done. These
results are compared to a phenomenological model that includes the pion pole
contribution. Within this model, the data favor a positive
transition form factor.Comment: DESY Report 15-14
Bose-Einstein correlations in hadron-pairs from lepto-production on nuclei ranging from hydrogen to xenon
Bose-Einstein correlations of like-sign charged hadrons produced in
deep-inelastic electron and positron scattering are studied in the HERMES
experiment using nuclear targets of H, H, He, He, N, Ne, Kr,
and Xe. A Gaussian approach is used to parametrize a two-particle correlation
function determined from events with at least two charged hadrons of the same
sign charge. This correlation function is compared to two different empirical
distributions that do not include the Bose-Einstein correlations. One
distribution is derived from unlike-sign hadron pairs, and the second is
derived from mixing like-sign pairs from different events. The extraction
procedure used simulations incorporating the experimental setup in order to
correct the results for spectrometer acceptance effects, and was tested using
the distribution of unlike-sign hadron pairs. Clear signals of Bose-Einstein
correlations for all target nuclei without a significant variation with the
nuclear target mass are found. Also, no evidence for a dependence on the
invariant mass W of the photon-nucleon system is found when the results are
compared to those of previous experiments
Evidence for Quark-Hadron Duality in the Proton Spin Asymmetry
Spin-dependent lepton-nucleon scattering data have been used to investigate
the validity of the concept of quark-hadron duality for the spin asymmetry
. Longitudinally polarised positrons were scattered off a longitudinally
polarised hydrogen target for values of between 1.2 and 12 GeV and
values of between 1 and 4 GeV. The average double-spin asymmetry in
the nucleon resonance region is found to agree with that measured in
deep-inelastic scattering at the same values of the Bjorken scaling variable
. This finding implies that the description of in terms of quark
degrees of freedom is valid also in the nucleon resonance region for values of
above 1.6 GeV.Comment: 5 pages, 1 eps figure, table added, new references added, in print in
Phys. Rev. Let
The -dependence of the generalised Gerasimov-Drell-Hearn integral for the deuteron, proton and neutron
The Gerasimov-Drell-Hearn (GDH) sum rule connects the anomalous contribution
to the magnetic moment of the target nucleus with an energy-weighted integral
of the difference of the helicity-dependent photoabsorption cross sections. The
data collected by HERMES with a deuterium target are presented together with a
re-analysis of previous measurements on the proton. This provides a measurement
of the generalised GDH integral covering simultaneously the nucleon-resonance
and the deep inelastic scattering regions. The contribution of the
nucleon-resonance region is seen to decrease rapidly with increasing . The
DIS contribution is sizeable over the full measured range, even down to the
lowest measured . As expected, at higher the data are found to be in
agreement with previous measurements of the first moment of . From data on
the deuteron and proton, the GDH integral for the neutron has been derived and
the proton--neutron difference evaluated. This difference is found to satisfy
the fundamental Bjorken sum rule at GeV.Comment: 12 pages, 10 figure
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