202 research outputs found
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A DUALITY THEORETIC VIEW ON LIMITS OF FINITE STRUCTURES
A systematic theory of structural limits for finite models has been developed by Nešetřil and Ossona de Mendez. It is based on the insight that the collection of finite structures can be embedded, via a map they call the Stone pairing, in a space of measures, where the desired limits can be computed. We show that a closely related but finer grained space of (finitely additive) measures arises—via Stone-Priestley duality and the notion of types from model theory—by enriching the expressive power of first-order logic with certain “probabilistic operators”. We provide a sound and complete calculus for this extended logic and expose the functorial nature of this construction. The consequences are two-fold. On the one hand, we identify the logical gist of the theory of structural limits. On the other hand, our construction shows that the duality theoretic variant of the Stone pairing captures the adding of a layer of quantifiers, thus making a strong link to recent work on semiring quantifiers in logic on words. In the process, we identify the model theoretic notion of types as the unifying concept behind this link. These results contribute to bridging the strands of logic in computer science which focus on semantics and on more algorithmic and complexity related areas, respectively
A duality theoretic view on limits of finite structures: Extended version
A systematic theory of structural limits for finite models has been developed by Nešetřil and Ossona de Mendez. It is based on the insight that the collection of finite structures can be embedded, via a map they call the Stone pairing, in a space of measures, where the desired limits can be computed. We show that a closely related but finer grained space of (finitely additive) measures arises—via Stone-Priestley duality and the notion of types from model theory—by enriching the expressive power of first-order logic with certain “probabilistic operators”. We provide a sound and complete calculus for this extended logic and expose the functorial nature of this construction. The consequences are two-fold. On the one hand, we identify the logical gist of the theory of structural limits. On the other hand, our construction shows that the duality theoretic variant of the Stone pairing captures the adding of a layer of quantifiers, thus making a strong link to recent work on semiring quantifiers in logic on words. In the process, we identify the model theoretic notion of types as the unifying concept behind this link. These results contribute to bridging the strands of logic in computer science which focus on semantics and on more algorithmic and complexity related areas, respectively
Assessment of anthracycline-induced cardiotoxicity with electrocardiography
Aim: Monitoring of anthracycline-induced cardiotoxicity with electrocardiography (ECG) and comparing ECG changes with findings
on echocardiography (ECHO). Methods: A total of 26 adult acute leukemia patients (mean age 46.2 ± 12.4 years, 15 males)
treated with 2–6 cycles of anthracycline-based chemotherapy (CT) were studied. Cardiac evaluation was performed at the baseline
(before CT), after first CT, after last CT (cumulative anthracycline dose 464.3 ± 117.5 mg/m2
) and circa 6 months after CT.
Time ECG parameters, QRS voltage, presence of repolarization changes, arrhythmias and other abnormalities were evaluated.
Results: During treatment and follow-up, we found a statistical significant QTc interval prolongation — 414.7 ± 16.0 ms (before
CT), 419.6 ± 21.6 ms(after first CT), 428.0 ± 16.2 ms(after last CT) and 430.1 ± 18.4 ms(6 months after CT). Significant QTc
interval prolongation (> 450 ms) occurred in 3 patients after first CT, in 4 patients after last CT and in 5 patients within 6 months
after CT. Significant total QRS voltage lowering in the limb leads (> 1.0 mV versus before CT) occurred in 3 patients after first
CT, in 5 patients after last CT and in 6 patients within 6 months after CT. We found a statistically significant correlation between
decreased QRS voltage, QTc interval prolongation and left ventricular (LV) dysfunction on ECHO. Repolarization changes associated
with oncology treatment were present in 9 patients within 6 months after CT. Conclusion: Anthracycline treatment is associated
with changes in electrical activity of the myocardium. Prolonged QTc interval represents a risk for development of malignant
ventricular arrhythmias. Decreased QRS voltage and prolonged QTc interval after anthracycline treatment could correlate with
LV dysfunction on ECHO. Further studies will be needed to prove whether these ECG changes could serve as an accessible and
non-invasive screening method indicating LV dysfunction after anthracycline treatment
Cardiovascular changes associated with infusion of hematopoietic cell grafts in oncohematological patients — impact of cryopreservation with dimethylsulfoxide
Aim: Dimethylsulfoxide (DMSO) is the most frequently used agent for hematopoietic cell (HC) graft cryopreservation. This study
aimed to monitor blood pressure and heart rate (HR) during HC graft infusion and assess the impact of cryopreservation with
DMSO. Methods: 153 HC graft infusions in 153 consecutive hematological patients (mean age 49.1 ± 12.6 years; 80 males) were
evaluated. Cryopreservation with DMSO was used in 133 grafts (DMSO group). Twenty grafts were infused directly without cryopreservation
(control group). Systolic blood pressure (SBP), diastolic blood pressure (DBP) and HR were measured immediately
before and after HC graft infusion. Results: SBP and DBP increased significantly after graft infusions cryopreserved with DMSO
(p 10 mmHg) in SBP were seen in 42 (31.6%) patients; in DBP in 31 (23.3%)
patients. Changes in HR were non-significant in DMSO group. Increases in BP and HR correlated with increasing DMSO dose
(p < 0.01; p < 0.05, respectively). Changes in SBP, DBP and HR were non-significant in control group. Conclusion: HC graft
infusions cryopreserved with DMSO could cause statistically significant increases in SBP and DBP, without changes in HR. These
changes were mostly transient and asymptomatic, not requiring therapeutic intervention. However, they might cause complications,
especially in patients with preexisting cardiovascular disease, who should be monitored closely during HC transplantation
Spin alignment measurements of the and vector mesons at RHIC
We present the first spin alignment measurements for the and
vector mesons produced at mid-rapidity with transverse momenta up
to 5 GeV/c at = 200 GeV at RHIC. The diagonal spin density
matrix elements with respect to the reaction plane in Au+Au collisions are
= 0.32 0.04 (stat) 0.09 (syst) for the
( GeV/c) and = 0.34 0.02 (stat) 0.03
(syst) for the ( GeV/c), and are constant with transverse
momentum and collision centrality. The data are consistent with the unpolarized
expectation of 1/3 and thus no evidence is found for the transfer of the
orbital angular momentum of the colliding system to the vector meson spins.
Spin alignments for and in Au+Au collisions were also measured
with respect to the particle's production plane. The result,
= 0.41 0.02 (stat) 0.04 (syst), is consistent with that in p+p
collisions, = 0.39 0.03 (stat) 0.06 (syst), also
measured in this work. The measurements thus constrain the possible size of
polarization phenomena in the production dynamics of vector mesons.Comment: 7 pages, 4 figures. fig.1 updated; one more reference added, one typo
corrected, published in PRC.77.06190
System-Size Independence of Directed Flow Measured at the BNL Relativistic Heavy-Ion Collider
We measure directed flow (ν_1) for charged particles in Au+Au and Cu+Cu collisions at √S_(NN)=200 and 62.4 GeV, as a function of pseudorapidity (η), transverse momentum (p_t), and collision centrality, based on data from the STAR experiment. We find that the directed flow depends on the incident energy but, contrary to all available model implementations, not on the size of the colliding system at a given centrality. We extend the validity of the limiting fragmentation concept to ν_1 in different collision systems, and investigate possible explanations for the observed sign change in ν_1(p_t)
Longitudinal double-spin asymmetry for inclusive jet production in p+p collisions at sqrt(s)=200 GeV
We report a new STAR measurement of the longitudinal double-spin asymmetry
A_LL for inclusive jet production at mid-rapidity in polarized p+p collisions
at a center-of-mass energy of sqrt(s) = 200 GeV. The data, which cover jet
transverse momenta 5 < p_T < 30 GeV/c, are substantially more precise than
previous measurements. They provide significant new constraints on the gluon
spin contribution to the nucleon spin through the comparison to predictions
derived from one global fit of polarized deep-inelastic scattering
measurements.Comment: 7 pages, 4 figures + 1 tabl
Measurements of meson production in relativistic heavy-ion collisions at RHIC
We present results for the measurement of meson production via its
charged kaon decay channel in Au+Au collisions at
, 130, and 200 GeV, and in and +Au collisions
at GeV from the STAR experiment at the BNL Relativistic
Heavy Ion Collider (RHIC). The midrapidity () meson transverse
momentum () spectra in central Au+Au collisions are found to be well
described by a single exponential distribution. On the other hand, the
spectra from , +Au and peripheral Au+Au collisions show power-law tails
at intermediate and high and are described better by Levy
distributions. The constant yield ratio vs beam species, collision
centrality and colliding energy is in contradiction with expectations from
models having kaon coalescence as the dominant mechanism for production
at RHIC. The yield ratio as a function of is consistent
with a model based on the recombination of thermal quarks up to GeV/, but disagrees at higher transverse momenta. The measured nuclear
modification factor, , for the meson increases above unity at
intermediate , similar to that for pions and protons, while is
suppressed due to the energy loss effect in central Au+Au collisions. Number of
constituent quark scaling of both and for the meson
with respect to other hadrons in Au+Au collisions at =200 GeV
at intermediate is observed. These observations support quark
coalescence as being the dominant mechanism of hadronization in the
intermediate region at RHIC.Comment: 22 pages, 21 figures, 4 table
Enhanced strange baryon production in Au+Au collisions compared to p+p at sqrts = 200 GeV
We report on the observed differences in production rates of strange and
multi-strange baryons in Au+Au collisions at sqrts = 200 GeV compared to pp
interactions at the same energy. The strange baryon yields in Au+Au collisions,
then scaled down by the number of participating nucleons, are enhanced relative
to those measured in pp reactions. The enhancement observed increases with the
strangeness content of the baryon, and increases for all strange baryons with
collision centrality. The enhancement is qualitatively similar to that observed
at lower collision energy sqrts =17.3 GeV. The previous observations are for
the bulk production, while at intermediate pT, 1 < pT< 4 GeV/c, the strange
baryons even exceed binary scaling from pp yields.Comment: 7 pages, 4 figures. Printed in PR
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