609,193 research outputs found
A percolation system with extremely long range connections and node dilution
We study the very long-range bond-percolation problem on a linear chain with
both sites and bonds dilution. Very long range means that the probability
for a connection between two occupied sites at a distance
decays as a power law, i.e. when , and
when . Site dilution means that the occupancy probability of a site
is . The behavior of this model results from the competition
between long-range connectivity, which enhances the percolation, and site
dilution, which weakens percolation. The case with is
well-known, being the exactly solvable mean-field model. The percolation order
parameter is investigated numerically for different values of
, and . We show that in the ranges
and the percolation order parameter depends only on
the average connectivity of sites, which can be explicitly computed in
terms of the three parameters , and
Automatic construction of known-item finding test beds
This work is an initial study on the utility of automatically generated queries for evaluating known-item retrieval and how such queries compare to real queries. The main advantage of automatically generating queries is that for any given test collection numerous queries can be produced at minimal cost. For evaluation, this has huge ramifications as state-of-the-art algorithms can be tested on different types of generated queries which mimic particular querying styles that a user may adopt. Our approach draws upon previous research in IR which has probabilistically generated simulated queries for other purposes [2, 3]
Surprises in the phase diagram of an Anderson impurity model for a single C molecule
We find by Wilson numerical renormalization group and conformal field theory
that a three-orbital Anderson impurity model for a C molecule has a
very rich phase diagram which includes non-Fermi-liquid stable and unstable
fixed points with interesting properties, most notably high sensitivity to
doping . We discuss the implications of our results to the conductance
behavior of C-based single-molecule transistor devices.Comment: 4 pages, 3 figures, 2 tables. Accepted versio
Current Classification of the Families of Coleoptera
(excerpt)
Several works on the order Coleoptera have appeared in recent years, some of them creating new superfamilies, others modifying the constitution of these or creating new families, finally others are genera1 revisions of the order. The authors believe that the current classification of this order, incorporating these changes would prove useful. The following outline is based mainly on Crowson (1960, 1964, 1966, 1967, 1971, 1972, 1973) and Crowson and Viedma (1964). For characters used on classification see Viedma (1972) and for family synonyms Abdullah (1969). Major features of this conspectus are the rejection of the two sections of Adephaga (Geadephaga and Hydradephaga), based on Bell (1966) and the new sequence of Heteromera, based mainly on Crowson (1966), with adaptations
Notes on Insect Injection, Anesthetization, and Bleeding.
(excerpt)
In recent years there has been a burgeoning interest in insect cytogenetics, sometimes involving in vivo cultures of haematocytes for chromosomal analysis. Mitotic poisons, such as colchicine (Tyrkus, 1971), are commonly injected to produce metaphase plates. Likewise, injection of toxins is now common-place in applied insect research. However, surprisingly little general information on injection is available in the literature. The dictates of morphology determine the gross procedure to be used. The kind of needle and syringe, the amount of fluid to be administered, and the necessity of optical aids are a function of the size of the insect recipient. Once these decisions are made, other considerations must still be weighed, including comparative exoskeletal toughness and the insect\u27s stage of development, which are important in determining possible areas for needle penetration
Unified formalism for higher-order non-autonomous dynamical systems
This work is devoted to giving a geometric framework for describing
higher-order non-autonomous mechanical systems. The starting point is to extend
the Lagrangian-Hamiltonian unified formalism of Skinner and Rusk for these
kinds of systems, generalizing previous developments for higher-order
autonomous mechanical systems and first-order non-autonomous mechanical
systems. Then, we use this unified formulation to derive the standard
Lagrangian and Hamiltonian formalisms, including the Legendre-Ostrogradsky map
and the Euler-Lagrange and the Hamilton equations, both for regular and
singular systems. As applications of our model, two examples of regular and
singular physical systems are studied.Comment: 43 pp. We have corrected and clarified the statement of Propositions
2 and 3. A remark is added after Proposition
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