932 research outputs found
Oblique triangular antiferromagnetic phase in CsCuCoCl
The spin-1/2 stacked triangular antiferromagnet CsCuCoCl with
undergoes two phase transitions at zero field. The
low-temperature phase is produced by the small amount of Co doping. In
order to investigate the magnetic structures of the two ordered phases, the
neutron elastic scattering experiments have been carried out for the sample
with . It is found that the intermediate phase is identical to
the ordered phase of CsCuCl, and that the low-temperature phase is an
oblique triangular antiferromagnetic phase in which the spins form a triangular
structure in a plane tilted from the basal plane. The tilting angle which is
42 at K decreases with increasing temperature, and becomes
zero at K. An off-diagonal exchange term is proposed as the
origin of the oblique phase.Comment: 6 pages, 7 figure
Chiral Perturbation Theory, the expansion and Regge behaviour determine the structure of the lightest scalar meson
The leading behaviour of Unitarised Chiral Perturbation Theory
distinguishes the nature of the and the . At one loop order the
is a meson, while the is not. However, semi-local
duality between resonances and Regge behaviour cannot be satisfied for larger
, if such a distinction holds. While the at is inevitably
dominated by its di-pion component, Unitarised Chiral Perturbation Theory
beyond one loop order reveals that as increases above 6-8, the
has a sub-dominant fraction up at 1.2 GeV. Remarkably this ensures
semi-local duality is fulfilled for the range of , where the
unitarisation procedure adopted applies.Comment: 22 pages, 8 figures. Version to be published in Physical Review
Role of the (1535) in the and reactions
We study the and
reactions with a unitary chiral approach. We find that the unitary chiral
approach, which generates the dynamically, can describe the data
reasonably well, particularly the ratio of the integrated cross sections. This
study provides further support for the unitary chiral description of the
. We also discuss some subtle differences between the coupling
constants determined from the unitary chiral approach and those determined from
phenomenological studies.Comment: version to appear in PRC; certain features of the approach clarifie
The Multi-center Evaluation of the Accuracy of the Contrast MEdium INduced Pd/Pa RaTiO in Predicting FFR (MEMENTO-FFR) Study.
AIMS:
Adenosine administration is needed for the achievement of maximal hyperaemia fractional flow reserve (FFR) assessment. The objective was to test the accuracy of Pd/Pa ratio registered during submaximal hyperaemia induced by non-ionic contrast medium (contrast FFR [cFFR]) in predicting FFR and comparing it to the performance of resting Pd/Pa in a collaborative registry of 926 patients enrolled in 10 hospitals from four European countries (Italy, Spain, France and Portugal).
METHODS AND RESULTS:
Resting Pd/Pa, cFFR and FFR were measured in 1,026 coronary stenoses functionally evaluated using commercially available pressure wires. cFFR was obtained after intracoronary injection of contrast medium, while FFR was measured after administration of adenosine. Resting Pd/Pa and cFFR were significantly higher than FFR (0.93±0.05 vs. 0.87±0.08 vs. 0.84±0.08, p<0.001). A strong correlation and a close agreement at Bland-Altman analysis between cFFR and FFR were observed (r=0.90, p<0.001 and 95% CI of disagreement: from -0.042 to 0.11). ROC curve analysis showed an excellent accuracy (89%) of the cFFR cut-off of ≤0.85 in predicting an FFR value ≤0.80 (AUC 0.95 [95% CI: 0.94-0.96]), significantly better than that observed using resting Pd/Pa (AUC: 0.90, 95% CI: 0.88-0.91; p<0.001). A cFFR/FFR hybrid approach showed a significantly lower number of lesions requiring adenosine than a resting Pd/Pa/FFR hybrid approach (22% vs. 44%, p<0.0001).
CONCLUSIONS:
cFFR is accurate in predicting the functional significance of coronary stenosis. This could allow limiting the use of adenosine to obtain FFR to a minority of stenoses with considerable savings of time and costs.info:eu-repo/semantics/publishedVersio
Nature of the axial-vector mesons from their Nc behavior within the chiral unitary approach
By describing within the chiral unitary approach the s-wave interaction of
the vector meson nonet with the octet of pseudoscalar Goldstone Bosons, we find
that the main component of the axial vector mesons b_1(1235), h_1(1170),
h_1(1380), a_1(1260), f_1(1285) and the two states associated to the K_1(1270)
does not follow the QCD dependence on the number of colors for ordinary qqbar
mesons.Comment: 18 pages, 5 figures, to be published in EPJ
High prevalence of scrapie in a dairy goat herd: tissue distribution of disease-associated PrP and effect of PRNP genotype and age
Following a severe outbreak of clinical scrapie in 2006–2007, a
large dairy goat herd was culled
and 200 animals were selected for post-mortem examinations in order to
ascertain the prevalence of infection,
the effect of age, breed and PRNP genotype on the susceptibility to scrapie,
the tissue distribution of diseaseassociated
PrP (PrP), and the comparative efficiency of different diagnostic methods.
As determined by immunohistochemical (IHC) examinations with Bar224 PrP antibody, the
prevalence of preclinical infection
was very high (72/200; 36.0%), with most infected animals being positive
for PrP in lymphoreticular system
(LRS) tissues (68/72; 94.4%) compared to those that were positive in
brain samples (38/72; 52.8%). The
retropharyngeal lymph node and the palatine tonsil showed the highest
frequency of PrP accumulation (87.3%
and 84.5%, respectively), while the recto-anal mucosa-associated lymphoid
tissue (RAMALT) was positive in
only 30 (41.7%) of the infected goats. However, the efficiency of rectal
and palatine tonsil biopsies taken
shortly before necropsy was similar. The probability of brain and RAMALT
being positive directly
correlated with the spread of PrP within the LRS. The prevalence of
infection was influenced by PRNP
genetics at codon 142 and by the age of the goats: methionine carriers older
than 60 months showed a much
lower prevalence of infection (12/78; 15.4%) than those younger than 60 months (20/42; 47.6%); these last
showed prevalence values similar to isoleucine homozygotes of any age
(40/80; 50.0%). Two of seven goats
with definite signs of scrapie were negative for PrP in brain but positive
in LRS tissues, and one goat showed
biochemical and IHC features of PrP different from all other infected
goats. The results of this study have
implications for surveillance and control policies for scrapie in goats
Equivalence between Kaluza Klein modes of gravitinos and goldstinos in brane induced supersymmetry breaking
We identify the goldstino fields that give mass to the Kaluza Klein modes of
five dimensional supergravity, when supersymmetry breaking is induced by brane
effects. We then proof the four dimensional Equivalence Theorem that, in
renormalizable gauges, allows for the replacement of Kaluza Klein modes of
helicity gravitinos in terms of goldstinos. Finally we identify the
five dimensional renormalizable gauge fixing that leads to the Equivalence
Theorem.Comment: Final version published in JHEP. Typo corrected in eq. 2.
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