1,017 research outputs found
Long time behaviour and self-similarity in an addition model with slow Input of monomers
We consider a coagulation equation with constant coefficients and a time dependent
power law input of monomers. We discuss the asymptotic behaviour of solutions as , and we prove solutions converge to a similarity profile along the non-characteristic
direction
The masses of vector supermultiplet and of the Higgs supertriplet in supersymmetric SU(5) model
The masses of vector supermultiplet and of the Higgs supertriplet in standard
supersymmetric SU(5) model are calculated. Taking into account uncertainties
related with the initial coupling constants and threshold corrections we find
that in supersymmetric SU(5) model the scale of the supersymmetry breaking
could be up to 50 Tev. We find that in the extensions of the standard SU(5)
supersymmetric model it is possible to increase the supersymmetry breaking
scale up to Gev. In standard supersymmetric SU(5) model it is
possible to increase the GUT scale up to Gev provided that
the masses of chiral superoctets and supertriplets are . We also propose SU(5) supersymmetric model with 6 light superdoublets and
superoctet with a mass Gev.Comment: 11 pages, latex, no figure
The signed loop approach to the Ising model: foundations and critical point
The signed loop method is a beautiful way to rigorously study the
two-dimensional Ising model with no external field. In this paper, we explore
the foundations of the method, including details that have so far been
neglected or overlooked in the literature. We demonstrate how the method can be
applied to the Ising model on the square lattice to derive explicit formal
expressions for the free energy density and two-point functions in terms of
sums over loops, valid all the way up to the self-dual point. As a corollary,
it follows that the self-dual point is critical both for the behaviour of the
free energy density, and for the decay of the two-point functions.Comment: 38 pages, 7 figures, with an improved Introduction. The final
publication is available at link.springer.co
Outcome from balloon induced coronary artery dissection after intracoronary beta radiation
OBJECTIVE: To evaluate the healing of balloon induced coronary artery
dissection in individuals who have received beta radiation treatment and
to propose a new intravascular ultrasound (IVUS) dissection score to
facilitate the comparison of dissection through time. DESIGN:
Retrospective study. SETTING: Tertiary referral centre. PATIENTS: 31
patients with stable angina pectoris, enrolled in the beta energy
restenosis trial (BERT-1.5), were included. After excluding those who
underwent stent implantation, the evaluable population was 22 patients.
INTERVENTIONS: Balloon angioplasty and intracoronary radiation followed by
quantitative coronary angiography (QCA) and IVUS. Repeat QCA and IVUS were
performed at six month follow up. MAIN OUTCOME MEASURES: QCA and IVUS
evidence of healing of dissection. Dissection classification for
angiography was by the National Heart Lung Blood Institute scale. IVUS
proven dissection was defined as partial or complete. The following IVUS
defined characteristics of dissection were described in the affected
coronary segments: length, depth, arc circumference, presence of flap, and
dissection score. Dissection was defined as healed when all features of
dissection had resolved. The calculated dose of radiation received by the
dissected area in those with healed versus non-healed dissection was also
compared. RESULTS: Angiography (type A = 5, B = 7, C = 4) and IVUS proven
(partial = 12, complete = 4) dissections were seen in 16 patients
following intervention. At six month follow up, six and eight unhealed
dissections were seen by angiography (A = 2, B = 4) and IVUS (partial = 7,
complete = 1), respectively. The mean IVUS dissection score was 5.2 (range
3-8) following the procedure, and 4.6 (range 3-7) at follow up. No
correlation was found between the dose prescribed in the treated area and
the presence of unhealed disse
Spin asymmetry A_1^d and the spin-dependent structure function g_1^d of the deuteron at low values of x and Q^2
We present a precise measurement of the deuteron longitudinal spin asymmetry
A_1^d and of the deuteron spin-dependent structure function g_1^d at Q^2 < 1
GeV^2 and 4*10^-5 < x < 2.5*10^-2 based on the data collected by the COMPASS
experiment at CERN during the years 2002 and 2003. The statistical precision is
tenfold better than that of the previous measurement in this region. The
measured A_1^d and g_1^d are found to be consistent with zero in the whole
range of x.Comment: 17 pages, 10 figure
Gluon polarization in the nucleon from quasi-real photoproduction of high-pT hadron pairs
We present a determination of the gluon polarization Delta G/G in the
nucleon, based on the helicity asymmetry of quasi-real photoproduction events,
Q^2<1(GeV/c)^2, with a pair of large transverse-momentum hadrons in the final
state. The data were obtained by the COMPASS experiment at CERN using a 160 GeV
polarized muon beam scattered on a polarized 6-LiD target. The helicity
asymmetry for the selected events is = 0.002 +- 0.019(stat.) +-
0.003(syst.). From this value, we obtain in a leading-order QCD analysis Delta
G/G=0.024 +- 0.089(stat.) +- 0.057(syst.) at x_g = 0.095 and mu^2 =~ 3
(GeV}/c)^2.Comment: 10 pages, 3 figure
Measurement of the Spin Structure of the Deuteron in the DIS Region
We present a new measurement of the longitudinal spin asymmetry A_1^d and the
spin-dependent structure function g_1^d of the deuteron in the range 1 GeV^2 <
Q^2 < 100 GeV^2 and 0.004< x <0.7. The data were obtained by the COMPASS
experiment at CERN using a 160 GeV polarised muon beam and a large polarised
6-LiD target. The results are in agreement with those from previous experiments
and improve considerably the statistical accuracy in the region 0.004 < x <
0.03.Comment: 10 pages, 6 figures, subm. to PLB, revised: author list, Fig. 4,
details adde
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