128 research outputs found
Monotone graph limits and quasimonotone graphs
The recent theory of graph limits gives a powerful framework for
understanding the properties of suitable (convergent) sequences of
graphs in terms of a limiting object which may be represented by a symmetric
function on , i.e., a kernel or graphon. In this context it is
natural to wish to relate specific properties of the sequence to specific
properties of the kernel. Here we show that the kernel is monotone (i.e.,
increasing in both variables) if and only if the sequence satisfies a
`quasi-monotonicity' property defined by a certain functional tending to zero.
As a tool we prove an inequality relating the cut and norms of kernels of
the form with and monotone that may be of interest in its
own right; no such inequality holds for general kernels.Comment: 38 page
Amicable pairs and aliquot cycles for elliptic curves
An amicable pair for an elliptic curve E/Q is a pair of primes (p,q) of good
reduction for E satisfying #E(F_p) = q and #E(F_q) = p. In this paper we study
elliptic amicable pairs and analogously defined longer elliptic aliquot cycles.
We show that there exist elliptic curves with arbitrarily long aliqout cycles,
but that CM elliptic curves (with j not 0) have no aliqout cycles of length
greater than two. We give conjectural formulas for the frequency of amicable
pairs. For CM curves, the derivation of precise conjectural formulas involves a
detailed analysis of the values of the Grossencharacter evaluated at a prime
ideal P in End(E) having the property that #E(F_P) is prime. This is especially
intricate for the family of curves with j = 0.Comment: 53 page
Measurement of the LT-asymmetry in \pi^0 electroproduction at the energy of the \Delta (1232) resonance
The reaction p(e,e'p)pi^0 has been studied at Q^2=0.2 (GeV/c)^2 in the region
of W=1232 MeV. From measurements left and right of q, cross section asymmetries
\rho_LT have been obtained in forward kinematics \rho_LT(\theta_\pi^0=20deg) =
(-11.68 +/- 2.36_stat +/- 2.36_sys)$ and backward kinematics
\rho_LT(\theta_\pi^0=160deg) =(12.18 +/- 0.27_stat +/- 0.82_sys). Multipole
ratios \Re(S_1+^* M_1+)/|M_1+|^2 and \Re(S_0+^* M_1+)/|M_1+|^2 were determined
in the framework of the MAID2003 model. The results are in agreement with older
data. The unusally strong negative \Re(S_0+^* M_1+)/|M_1+|^2 required to bring
also the result of Kalleicher et al. in accordance with the rest of the data is
almost excluded.Comment: 7 pages, 7 figures, 4 tables. Changed content. Accepted for
publication in EPJ
High platelet reactivity in patients with acute coronary syndromes undergoing percutaneous coronary intervention: Randomised controlled trial comparing prasugrel and clopidogrel
Background: Prasugrel is more effective than clopidogrel in reducing platelet aggregation in acute coronary syndromes. Data available on prasugrel reloading in clopidogrel treated patients with high residual platelet reactivity (HRPR) i.e. poor responders, is limited. Objectives: To determine the effects of prasugrel loading on platelet function in patients on clopidogrel and high platelet reactivity undergoing percutaneous coronary intervention for acute coronary syndrome (ACS). Patients: Patients with ACS on clopidogrel who were scheduled for PCI found to have a platelet reactivity ≥40 AUC with the Multiplate Analyzer, i.e. “poor responders” were randomised to prasugrel (60 mg loading and 10 mg maintenance dose) or clopidogrel (600 mg reloading and 150 mg maintenance dose). The primary outcome measure was proportion of patients with platelet reactivity <40 AUC 4 hours after loading with study medication, and also at one hour (secondary outcome). 44 patients were enrolled and the study was terminated early as clopidogrel use decreased sharply due to introduction of newer P2Y12 inhibitors. Results: At 4 hours after study medication 100% of patients treated with prasugrel compared to 91% of those treated with clopidogrel had platelet reactivity <40 AUC (p = 0.49), while at 1 hour the proportions were 95% and 64% respectively (p = 0.02). Mean platelet reactivity at 4 and 1 hours after study medication in prasugrel and clopidogrel groups respectively were 12 versus 22 (p = 0.005) and 19 versus 34 (p = 0.01) respectively. Conclusions: Routine platelet function testing identifies patients with high residual platelet reactivity (“poor responders”) on clopidogrel. A strategy of prasugrel rather than clopidogrel reloading results in earlier and more sustained suppression of platelet reactivity. Future trials need to identify if this translates into clinical benefit
Decomposition of semigroup algebras
Let A \subseteq B be cancellative abelian semigroups, and let R be an
integral domain. We show that the semigroup ring R[B] can be decomposed, as an
R[A]-module, into a direct sum of R[A]-submodules of the quotient ring of R[A].
In the case of a finite extension of positive affine semigroup rings we obtain
an algorithm computing the decomposition. When R[A] is a polynomial ring over a
field we explain how to compute many ring-theoretic properties of R[B] in terms
of this decomposition. In particular we obtain a fast algorithm to compute the
Castelnuovo-Mumford regularity of homogeneous semigroup rings. As an
application we confirm the Eisenbud-Goto conjecture in a range of new cases.
Our algorithms are implemented in the Macaulay2 package MonomialAlgebras.Comment: 12 pages, 2 figures, minor revisions. Package may be downloaded at
http://www.math.uni-sb.de/ag/schreyer/jb/Macaulay2/MonomialAlgebras/html
Elliptic flow of charged particles in Pb-Pb collisions at 2.76 TeV
We report the first measurement of charged particle elliptic flow in Pb-Pb
collisions at 2.76 TeV with the ALICE detector at the CERN Large Hadron
Collider. The measurement is performed in the central pseudorapidity region
(||<0.8) and transverse momentum range 0.2< < 5.0 GeV/. The
elliptic flow signal v, measured using the 4-particle correlation method,
averaged over transverse momentum and pseudorapidity is 0.087 0.002
(stat) 0.004 (syst) in the 40-50% centrality class. The differential
elliptic flow v reaches a maximum of 0.2 near = 3
GeV/. Compared to RHIC Au-Au collisions at 200 GeV, the elliptic flow
increases by about 30%. Some hydrodynamic model predictions which include
viscous corrections are in agreement with the observed increase.Comment: 10 pages, 4 captioned figures, published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/389
Child and adolescent psychiatric patients and later criminality
<p>Abstract</p> <p>Background</p> <p>Sweden has an extensive child and adolescent psychiatric (CAP) research tradition in which longitudinal methods are used to study juvenile delinquency. Up to the 1980s, results from descriptions and follow-ups of cohorts of CAP patients showed that children's behavioural disturbances or disorders and school problems, together with dysfunctional family situations, were the main reasons for families, children, and youth to seek help from CAP units. Such factors were also related to registered criminality and registered alcohol and drug abuse in former CAP patients as adults. This study investigated the risk for patients treated 1975–1990 to be registered as criminals until the end of 2003.</p> <p>Methods</p> <p>A regional sample of 1,400 former CAP patients, whose treatment occurred between 1975 and 1990, was followed to 2003, using database-record links to the Register of Persons Convicted of Offences at the National Council for Crime Prevention (NCCP).</p> <p>Results</p> <p>Every third CAP patient treated between 1975 and 1990 (every second man and every fifth woman) had entered the Register of Persons Convicted of Offences during the observation period, which is a significantly higher rate than the general population.</p> <p>Conclusion</p> <p>Results were compared to published results for CAP patients who were treated between 1953 and 1955 and followed over 20 years. Compared to the group of CAP patients from the 1950s, the results indicate that the risk for boys to enter the register for criminality has doubled and for girls, the risk seems to have increased sevenfold. The reasons for this change are discussed. Although hypothetical and perhaps speculative this higher risk of later criminality may be the result of lack of social control due to (1) rising consumption of alcohol, (2) changes in organisation of child social welfare work, (3) the school system, and (4) CAP methods that were implemented since 1970.</p
Stereotactic body radiotherapy for stage I lung cancer and small lung metastasis: evaluation of an immobilization system for suppression of respiratory tumor movement and preliminary results
<p>Abstract</p> <p>Background</p> <p>In stereotactic body radiotherapy (SBRT) for lung tumors, reducing tumor movement is necessary. In this study, we evaluated changes in tumor movement and percutaneous oxygen saturation (SpO<sub>2</sub>) levels, and preliminary clinical results of SBRT using the BodyFIX immobilization system.</p> <p>Methods</p> <p>Between 2004 and 2006, 53 consecutive patients were treated for 55 lesions; 42 were stage I non-small cell lung cancer (NSCLC), 10 were metastatic lung cancers, and 3 were local recurrences of NSCLC. Tumor movement was measured with fluoroscopy under breath holding, free breathing on a couch, and free breathing in the BodyFIX system. SpO<sub>2 </sub>levels were measured with a finger pulseoximeter under each condition. The delivered dose was 44, 48 or 52 Gy, depending on tumor diameter, in 4 fractions over 10 or 11 days.</p> <p>Results</p> <p>By using the BodyFIX system, respiratory tumor movements were significantly reduced compared with the free-breathing condition in both craniocaudal and lateral directions, although the amplitude of reduction in the craniocaudal direction was 3 mm or more in only 27% of the patients. The average SpO<sub>2 </sub>did not decrease by using the system. At 3 years, the local control rate was 80% for all lesions. Overall survival was 76%, cause-specific survival was 92%, and local progression-free survival was 76% at 3 years in primary NSCLC patients. Grade 2 radiation pneumonitis developed in 7 patients.</p> <p>Conclusion</p> <p>Respiratory tumor movement was modestly suppressed by the BodyFIX system, while the SpO<sub>2 </sub>level did not decrease. It was considered a simple and effective method for SBRT of lung tumors. Preliminary results were encouraging.</p
The ALICE Transition Radiation Detector: Construction, operation, and performance
The Transition Radiation Detector (TRD) was designed and built to enhance the capabilities of the ALICE detector at the Large Hadron Collider (LHC). While aimed at providing electron identification and triggering, the TRD also contributes significantly to the track reconstruction and calibration in the central barrel of ALICE. In this paper the design, construction, operation, and performance of this detector are discussed. A pion rejection factor of up to 410 is achieved at a momentum of 1 GeV/c in p-Pb collisions and the resolution at high transverse momentum improves by about 40% when including the TRD information in track reconstruction. The triggering capability is demonstrated both for jet, light nuclei, and electron selection. (c) 2017 CERN for the benefit of the Authors. Published by Elsevier B.V
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