983 research outputs found
Even faster sorting of (not only) integers
In this paper we introduce RADULS2, the fastest parallel sorter based on
radix algorithm. It is optimized to process huge amounts of data making use of
modern multicore CPUs. The main novelties include: extremely optimized
algorithm for handling tiny arrays (up to about a hundred of records) that
could appear even billions times as subproblems to handle and improved
processing of larger subarrays with better use of non-temporal memory stores
Saddles in the energy landscape: extensivity and thermodynamic formalism
We formally extend the energy landscape approach for the thermodynamics of
liquids to account for saddle points. By considering the extensive nature of
macroscopic potential energies, we derive the scaling behavior of saddles with
system size, as well as several approximations for the properties of low-order
saddles (i.e., those with only a few unstable directions). We then cast the
canonical partition function in a saddle-explicit form and develop, for the
first time, a rigorous energy landscape approach capable of reproducing trends
observed in simulations, in particular the temperature dependence of the energy
and fractional order of sampled saddles.Comment: 4 pages, 1 figur
On the Wang-Landau Method for Off-Lattice Simulations in the "Uniform" Ensemble
We present a rigorous derivation for off-lattice implementations of the
so-called "random-walk" algorithm recently introduced by Wang and Landau [PRL
86, 2050 (2001)]. Originally developed for discrete systems, the algorithm
samples configurations according to their inverse density of states using
Monte-Carlo moves; the estimate for the density of states is refined at each
simulation step and is ultimately used to calculate thermodynamic properties.
We present an implementation for atomic systems based on a rigorous separation
of kinetic and configurational contributions to the density of states. By
constructing a "uniform" ensemble for configurational degrees of freedom--in
which all potential energies, volumes, and numbers of particles are equally
probable--we establish a framework for the correct implementation of simulation
acceptance criteria and calculation of thermodynamic averages in the continuum
case. To demonstrate the generality of our approach, we perform sample
calculations for the Lennard-Jones fluid using two implementation variants and
in both cases find good agreement with established literature values for the
vapor-liquid coexistence locus.Comment: 21 pages, 4 figure
Potential energy landscape-based extended van der Waals equation
The inherent structures ({\it IS}) are the local minima of the potential
energy surface or landscape, , of an {\it N} atom system.
Stillinger has given an exact {\it IS} formulation of thermodynamics. Here the
implications for the equation of state are investigated. It is shown that the
van der Waals ({\it vdW}) equation, with density-dependent and
coefficients, holds on the high-temperature plateau of the averaged {\it IS}
energy. However, an additional ``landscape'' contribution to the pressure is
found at lower . The resulting extended {\it vdW} equation, unlike the
original, is capable of yielding a water-like density anomaly, flat isotherms
in the coexistence region {\it vs} {\it vdW} loops, and several other desirable
features. The plateau energy, the width of the distribution of {\it IS}, and
the ``top of the landscape'' temperature are simulated over a broad reduced
density range, , in the Lennard-Jones fluid. Fits to the
data yield an explicit equation of state, which is argued to be useful at high
density; it nevertheless reproduces the known values of and at the
critical point
Translation and Community in the work of Elizabeth Cary
Explores the role of female community within Elizabeth Cary\u27s translations and her play, The Tragedy of Mariam
Going global: The introduction of the Asian isopod Ianiropsis serricaudis Gurjanova (Crustacea: Peracarida) to North America and Europe
The Asian isopod Ianiropsis serricaudis is now well established in fouling communities, often associated with introduced ascidians, throughout the Northern Hemisphere but has gone largely unnoticed because of its diminutive size (typically less than 3 mm in length) and the difficulties of identifying small peracarid crustaceans. Known locations include the northeastern Pacific (Puget Sound, San Francisco Bay, and Monterey Bay), the northwestern Atlantic (from the Gulf of Maine to Barnegat Bay, NJ), and the northeastern Atlantic (England and the Netherlands). We predict that this species is widespread along North America and European coasts, and may already be introduced to cold temperate waters of the Southern Hemisphere as well
Effect of Multiple Medication on Hemoglohlin Content in Tranquilized Mice
Varying doses of medication were given tranquilized white mice. The hemoglobin content was measured by means of a Spectronic 20 colorimeter, using the Cannan chemical technique, with percent transmittance from colorimeter reading plotted against concentration grams per hemoglobin per 100 ml. blood of the standard. Comparison of length of medication, dosage, sex of animals, age of animals, and length of time on tranquilizer before medication was started recorded. Included in medication were varying amounts of sex hormones, and effects noted
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