65,897 research outputs found
Scalable Task-Based Algorithm for Multiplication of Block-Rank-Sparse Matrices
A task-based formulation of Scalable Universal Matrix Multiplication
Algorithm (SUMMA), a popular algorithm for matrix multiplication (MM), is
applied to the multiplication of hierarchy-free, rank-structured matrices that
appear in the domain of quantum chemistry (QC). The novel features of our
formulation are: (1) concurrent scheduling of multiple SUMMA iterations, and
(2) fine-grained task-based composition. These features make it tolerant of the
load imbalance due to the irregular matrix structure and eliminate all
artifactual sources of global synchronization.Scalability of iterative
computation of square-root inverse of block-rank-sparse QC matrices is
demonstrated; for full-rank (dense) matrices the performance of our SUMMA
formulation usually exceeds that of the state-of-the-art dense MM
implementations (ScaLAPACK and Cyclops Tensor Framework).Comment: 8 pages, 6 figures, accepted to IA3 2015. arXiv admin note: text
overlap with arXiv:1504.0504
Z_{12-I} Orbifold Compactification toward SUSY Standard Model
We explain the orbifold compactification in string models and present a
Z_{12-I} orbifold compactification toward supersymmetric standard models. We
also point out an effective R-parity from this string construction. The VEVs of
gauge singlets are chosen such that phenomenological constraints are satisfied.Comment: 13 pages with 5 figure. Talk presented at "CTP Symposium on SUSY at
LHC", Cairo, 11-14 March 200
Charmonium levels near threshold and the narrow state X(3872) \to \pi^{+}\pi^{-}\jpsi
We explore the influence of open-charm channels on charmonium properties, and
profile the 1:3D2, 1:3D3 and 2:1P1 charmonium candidates for X(3872). The
favored candidates, the 1:3D2 and 1:3D3 levels, both have prominent radiative
decays. The 1:3D2 might be visible in the channel, while
the dominant decay of the 1:3D3 state should be into . We propose
that additional discrete charmonium levels can be discovered as narrow
resonances of charmed and anticharmed mesons.Comment: 8 pages, 6 figures, uses RevTeX and boxedeps; few transcription
errors corrected in Tables IV and VI, three entries added in Table V, updated
references. Version to appear in Phys. Rev.
Dynamic transition and Shapiro-step melting in a frustrated Josephson-junction array
We consider a two-dimensional fully frustrated Josephson-junction array
driven by combined direct and alternating currents. Interplay between the mode
locking phenomenon, manifested by giant Shapiro steps in the current-voltage
characteristics, and the dynamic phase transition is investigated at finite
temperatures. Melting of Shapiro steps due to thermal fluctuations is shown to
be accompanied by the dynamic phase transition, the universality class of which
is also discussed
Variation in Boilerplate: Rational Design or Random Mutation?
Standard contract doctrine presumes that sophisticated parties choose their terminology carefully because they want courts or counterparts to understand what they intended. The implication of this “Rational Design” model of rational behavior is that courts should pay careful attention to the precise phrasing of contracts. Using a study of the sovereign bond market, we examine the Rational Design model as applied to standard-form contracting. In NML v. Argentina, federal courts in New York attached importance to the precise phrasing of the boilerplate contracts at issue. The industry promptly condemned the decision for a supposedly erroneous interpretation of a variant of a hoary boilerplate clause. Utilizing data on how contracting practices responded to the decision, we ask whether the market response indicates that parties in fact intended for the small variations in their contract language to embody a particular meaning. We find the data supports a model closer to random mutation rather than rational design
Leptogenesis origin of Dirac gaugino dark matter
The Dirac nature of the gauginos (and also the Higgsinos) can be realized in
-symmetric supersymmetry models. In this class of models, the Dirac bino (or
wino) with a small mixture of the Dirac Higgsinos is a good dark matter
candidate. When the seesaw mechanism with Higgs triplet superfields is
implemented to account for the neutrino masses and mixing, the leptogenesis
driven by the heavy triplet decay is shown to produce not only the
matter-antimatter asymmetry but also the asymmetric relic density of the Dirac
gaugino dark matter. The dark matter mass turns out to be controlled by the
Yukawa couplings of the heavy Higgs triplets, and it can be naturally at the
weak scale for a mild hierarchy of the Yukawa couplings.Comment: 9 pages. Restructured for clear presentation, corrected some errors
and typos. No change in conclusio
Low-frequency method for magnetothermopower and Nernst effect measurements on single crystal samples at low temperatures and high magnetic fields
We describe an AC method for the measurement of the longitudinal (Sxx) and
transverse (Sxy, i.e. Nernst) thermopower of mm-size single crystal samples at
low temperatures (T30 T). A low-frequency (33
mHz) heating method is used to increase the resolution, and to determine the
temperature gradient reliably in high magnetic fields. Samples are mounted
between two thermal blocks which are heated by a sinusoidal frequency f0 with a
p/2 phase difference. The phase difference between two heater currents gives a
temperature gradient at 2f0. The corresponding thermopower and Nernst effect
signals are extracted by using a digital signal processing method due. An
important component of the method involves a superconducting link, YBa2Cu3O7+d
(YBCO), which is mounted in parallel with sample to remove the background
magnetothermopower of the lead wires. The method is demonstrated for the quasi
two-dimensional organic conductor a-(BEDT-TTF)2KHg(SCN)4, which exhibits a
complex, magnetic field dependent ground state above 22.5 T at low
temperatures.Comment: 11 pages, 6 figures, 15 reference
Targeting kidney mesangium by nanoparticles of defined size
Nanoparticles are being investigated for numerous medical applications and are showing potential as an emerging class of carriers for drug delivery. Investigations on how the physicochemical properties (e.g., size, surface charge, shape, and density of targeting ligands) of nanoparticles enable their ability to overcome biological barriers and reach designated cellular destinations in sufficient amounts to elicit biological efficacy are of interest. Despite proven success in nanoparticle accumulation at cellular locations and occurrence of downstream therapeutic effects (e.g., target gene inhibition) in a selected few organs such as tumor and liver, reports on effective delivery of engineered nanoparticles to other organs still remain scarce. Here, we show that nanoparticles of ~75 ± 25-nm diameters target the mesangium of the kidney. These data show the effects of particle diameter on targeting the mesangium of the kidney. Because many diseases originate from this area of the kidney, our findings establish design criteria for constructing nanoparticle-based therapeutics for targeting diseases that involve the mesangium of the kidney
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