41,295 research outputs found
Heavy Quarkonium Dissociation Cross Sections in Relativistic Heavy-Ion Collisions
Many of the hadron-hadron cross sections required for the study of the
dynamics of matter produced in relativistic heavy-ion collisions can be
calculated using the quark-interchange model. Here we evaluate the low-energy
dissociation cross sections of , , , , and
in collision with , , and , which are important for
the interpretation of heavy-quarkonium suppression as a signature for the quark
gluon plasma. These comover dissociation processes also contribute to
heavy-quarkonium suppression, and must be understood and incorporated in
simulations of heavy-ion collisions before QGP formation can be established
through this signature.Comment: 38 pages, in LaTe
Ethnic Identity, Risk, and Protective Factors Related to Substance Abuse Among Mexican American Students
This study examines the relationship between ethnic identity, risk and protective factors for substance use and academic achievement. Risk factors include deviant behavior and susceptibility to peer influence, while the protective factor is self-reported confidence not to use substances. The sample consists of 2,370 Mexican American students enrolled in eighth, ninth, and tenth grades. Results of the analysis (MANOVA) revealed that females had more positive ethnic identity than males. Furthermore, males were significantly more susceptible to peer influence, reported higher levels of deviant behavior, used more substances and had lower grade point averages than females. There was no significant difference in their confidence not to use substances
Decoding of 1/2-rate (24,12) Golay codes
A decoding method for a (23,12) Golay code is extended to the important 1/2-rate (24,12) Golay code so that three errors can be corrected and four errors can be detected. It is shown that the method can be extended to any decoding method which can correct three errors in the (23,12) Golay code
Entanglement and purity of single- and two-photon states
Whereas single- and two-photon wave packets are usually treated as pure
states, in practice they will be mixed. We study how entanglement created with
mixed photon wave packets is degraded. We find in particular that the
entanglement of a delocalized single-photon state of the electro-magnetic field
is determined simply by its purity. We also discuss entanglement for two-photon
mixed states, as well as the influence of a vacuum component.Comment: 11 pages, 10 figures, 1 debuting autho
Schema Independent Relational Learning
Learning novel concepts and relations from relational databases is an
important problem with many applications in database systems and machine
learning. Relational learning algorithms learn the definition of a new relation
in terms of existing relations in the database. Nevertheless, the same data set
may be represented under different schemas for various reasons, such as
efficiency, data quality, and usability. Unfortunately, the output of current
relational learning algorithms tends to vary quite substantially over the
choice of schema, both in terms of learning accuracy and efficiency. This
variation complicates their off-the-shelf application. In this paper, we
introduce and formalize the property of schema independence of relational
learning algorithms, and study both the theoretical and empirical dependence of
existing algorithms on the common class of (de) composition schema
transformations. We study both sample-based learning algorithms, which learn
from sets of labeled examples, and query-based algorithms, which learn by
asking queries to an oracle. We prove that current relational learning
algorithms are generally not schema independent. For query-based learning
algorithms we show that the (de) composition transformations influence their
query complexity. We propose Castor, a sample-based relational learning
algorithm that achieves schema independence by leveraging data dependencies. We
support the theoretical results with an empirical study that demonstrates the
schema dependence/independence of several algorithms on existing benchmark and
real-world datasets under (de) compositions
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Sequence Classification Restricted Boltzmann Machines With Gated Units
For the classification of sequential data, dynamic Bayesian networks and recurrent neural networks (RNNs) are the preferred models. While the former can explicitly model the temporal dependences between the variables, and the latter have the capability of learning representations. The recurrent temporal restricted Boltzmann machine (RTRBM) is a model that combines these two features. However, learning and inference in RTRBMs can be difficult because of the exponential nature of its gradient computations when maximizing log likelihoods. In this article, first, we address this intractability by optimizing a conditional rather than a joint probability distribution when performing sequence classification. This results in the ``sequence classification restricted Boltzmann machine'' (SCRBM). Second, we introduce gated SCRBMs (gSCRBMs), which use an information processing gate, as an integration of SCRBMs with long short-term memory (LSTM) models. In the experiments reported in this article, we evaluate the proposed models on optical character recognition, chunking, and multiresident activity recognition in smart homes. The experimental results show that gSCRBMs achieve the performance comparable to that of the state of the art in all three tasks. gSCRBMs require far fewer parameters in comparison with other recurrent networks with memory gates, in particular, LSTMs and gated recurrent units (GRUs)
Universal Tomonaga-Luttinger liquid phases in one-dimensional strongly attractive SU(N) fermionic cold atoms
A simple set of algebraic equations is derived for the exact low-temperature
thermodynamics of one-dimensional multi-component strongly attractive fermionic
atoms with enlarged SU(N) spin symmetry and Zeeman splitting. Universal
multi-component Tomonaga-Luttinger liquid (TLL) phases are thus determined. For
linear Zeeman splitting, the physics of the gapless phase at low temperatures
belongs to the universality class of a two-component asymmetric TLL
corresponding to spin-neutral N-atom composites and spin-(N-1)/2 single atoms.
The equation of states is also obtained to open up the study of multi-component
TLL phases in 1D systems of N-component Fermi gases with population imbalance.Comment: 12 pages, 3 figure
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