11,678,085 research outputs found
T-T-T-That\u27s All, Folks!
The May 1996 Word Ways described the results of a National Public Radio competition of December 1995 in which listeners were challenged to write grammatical and understandable sentences containing the same word four or more times in succession. Some of the most interesting entries were based on repeated thats; this article summarizes them. Four thats is relatively easy, as achieved by the following strategy
Nontrivial t-Designs over Finite Fields Exist for All t
A - design over \F_q is a collection of -dimensional
subspaces of \F_q^n, called blocks, such that each -dimensional subspace
of \F_q^n is contained in exactly blocks. Such -designs over
\F_q are the -analogs of conventional combinatorial designs. Nontrivial
- designs over \F_q are currently known to exist only for
. Herein, we prove that simple (meaning, without repeated blocks)
nontrivial - designs over \F_q exist for all and ,
provided that and is sufficiently large. This may be regarded as
a -analog of the celebrated Teirlinck theorem for combinatorial designs
T-ALL and thymocytes : a message of noncoding RNAs
In the last decade, the role for noncoding RNAs in disease was clearly established, starting with microRNAs and later expanded towards long noncoding RNAs. This was also the case for T cell acute lymphoblastic leukemia, which is a malignant blood disorder arising from oncogenic events during normal T cell development in the thymus. By studying the transcriptomic profile of protein-coding genes, several oncogenic events leading to T cell acute lymphoblastic leukemia (T-ALL) could be identified. In recent years, it became apparent that several of these oncogenes function via microRNAs and long noncoding RNAs. In this review, we give a detailed overview of the studies that describe the noncoding RNAome in T-ALL oncogenesis and normal T cell development
Dynamic load balancing for the distributed mining of molecular structures
In molecular biology, it is often desirable to find common properties in large numbers of drug candidates. One family of
methods stems from the data mining community, where algorithms to find frequent graphs have received increasing attention over the
past years. However, the computational complexity of the underlying problem and the large amount of data to be explored essentially
render sequential algorithms useless. In this paper, we present a distributed approach to the frequent subgraph mining problem to
discover interesting patterns in molecular compounds. This problem is characterized by a highly irregular search tree, whereby no
reliable workload prediction is available. We describe the three main aspects of the proposed distributed algorithm, namely, a dynamic
partitioning of the search space, a distribution process based on a peer-to-peer communication framework, and a novel receiverinitiated
load balancing algorithm. The effectiveness of the distributed method has been evaluated on the well-known National Cancer
Institute’s HIV-screening data set, where we were able to show close-to linear speedup in a network of workstations. The proposed
approach also allows for dynamic resource aggregation in a non dedicated computational environment. These features make it suitable
for large-scale, multi-domain, heterogeneous environments, such as computational grids
Search for anomalous t t-bar production in the highly-boosted all-hadronic final state
A search is presented for a massive particle, generically referred to as a
Z', decaying into a t t-bar pair. The search focuses on Z' resonances that are
sufficiently massive to produce highly Lorentz-boosted top quarks, which yield
collimated decay products that are partially or fully merged into single jets.
The analysis uses new methods to analyze jet substructure, providing
suppression of the non-top multijet backgrounds. The analysis is based on a
data sample of proton-proton collisions at a center-of-mass energy of 7 TeV,
corresponding to an integrated luminosity of 5 inverse femtobarns. Upper limits
in the range of 1 pb are set on the product of the production cross section and
branching fraction for a topcolor Z' modeled for several widths, as well as for
a Randall--Sundrum Kaluza--Klein gluon. In addition, the results constrain any
enhancement in t t-bar production beyond expectations of the standard model for
t t-bar invariant masses larger than 1 TeV.Comment: Submitted to the Journal of High Energy Physics; this version
includes a minor typo correction that will be submitted as an erratu
All-graphene edge contacts: Electrical resistance of graphene T-junctions
Using ab-initio methods we investigate the possibility of three-terminal
graphene "T-junction" devices and show that these all-graphene edge contacts
are energetically feasible when the 1D interface itself is free from foreign
atoms. We examine the energetics of various junction structures as a function
of the atomic scale geometry. Three-terminal equilibrium Green's functions are
used to determine the transmission spectrum and contact resistance of the
system. We find that the most symmetric structures have a significant binding
energy, and we determine the contact resistances in the junction to be in the
range of 1-10 kOhm which is comparable to the best contact resistance reported
for edge-contacted graphene-metal contacts. We conclude that conducting
all-carbon T-junctions should be feasible
Phase separation at all interaction strengths in the t-J model
We investigate the phase diagram of the two-dimensional t-J model using a
recently developed Green's Function Monte Carlo method for lattice fermions. We
use the technique to calculate exact ground-state energies of the model on
large lattices. In contrast to many previous studies, we find the model phase
separates for all values of J/t. In particular, it is unstable at the hole
dopings and interaction strengths at which the model was thought to describe
the cuprate superconductors.Comment: Revtex, 4 pages, 3 figures. Some minor changes were made to the text
and figures, and some references were adde
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