225 research outputs found
Two-particle interference in standard and Bohmian quantum mechanics
The compatibility of standard and Bohmian quantum mechanics has recently been
challenged in the context of two-particle interference, both from a theoretical
and an experimental point of view. We analyze different setups proposed and
derive corresponding exact forms for Bohmian equations of motion. The equations
are then solved numerically, and shown to reproduce standard quantum-mechanical
results.Comment: Minor corrections, 2 references added, version to appear in J. Phys.
Conformal Invariance and Wave-Particle Duality
We present a conformally invariant generalized form of the free particle
action by connecting the wave and particle aspects through gravity. Conformal
invariance breaking is introduced by choosing a particular configurat$ of
dynamical variables. This leads to the geometrization of the quantum aspects of
matter.Comment: 5 page
Yeast Features: Identifying Significant Features Shared Among Yeast Proteins for Functional Genomics
Background
High throughput yeast functional genomics experiments are revealing associations among tens to hundreds of genes using numerous experimental conditions. To fully understand how the identified genes might be involved in the observed system, it is essential to consider the widest range of biological annotation possible. Biologists often start their search by collating the annotation provided for each protein within databases such as the Saccharomyces Genome Database, manually comparing them for similar features, and empirically assessing their significance. Such tasks can be automated, and more precise calculations of the significance can be determined using established probability measures. 
Results
We developed Yeast Features, an intuitive online tool to help establish the significance of finding a diverse set of shared features among a collection of yeast proteins. A total of 18,786 features from the Saccharomyces Genome Database are considered, including annotation based on the Gene Ontology’s molecular function, biological process and cellular compartment, as well as conserved domains, protein-protein and genetic interactions, complexes, metabolic pathways, phenotypes and publications. The significance of shared features is estimated using a hypergeometric probability, but novel options exist to improve the significance by adding background knowledge of the experimental system. For instance, increased statistical significance is achieved in gene deletion experiments because interactions with essential genes will never be observed. We further demonstrate the utility by suggesting the functional roles of the indirect targets of an aminoglycoside with a known mechanism of action, and also the targets of an herbal extract with a previously unknown mode of action. The identification of shared functional features may also be used to propose novel roles for proteins of unknown function, including a role in protein synthesis for YKL075C.
Conclusions
Yeast Features (YF) is an easy to use web-based application (http://software.dumontierlab.com/yeastfeatures/) which can identify and prioritize features that are shared among a set of yeast proteins. This approach is shown to be valuable in the analysis of complex data sets, in which the extracted associations revealed significant functional relationships among the gene products.

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Intraneural Hemangioma: Case Report of a Rare Tibial Nerve Lesion.
An intraneural hemangioma is a rare, benign mesodermal lesion. We present a case of a three-year-old female with the inability to straighten her right knee and fullness over the right popliteal fossa for one year. Magnetic resonance imaging (MRI) demonstrated a T2 hyperintense lesion of the popliteal fossa, within the tibial nerve. The patient underwent an uncomplicated right knee excisional biopsy, which confirmed the diagnosis of an intraneural hemangioma. Although rare, an intraneural hemangioma should be considered in the differential diagnosis of a soft tissue lesion located in the expected course of a peripheral nerve
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Chronic thoracic hemisection spinal cord injury in adult rats induces a progressive decline in transmission from uninjured fibers to lumbar motoneurons
Although most spinal cord injuries are anatomically incomplete, only limited functional recovery has been observed in people and rats with partial lesions. To address why surviving fibers cannot mediate more complete recovery, we evaluated the physiological and anatomical status of spared fibers after unilateral hemisection (HX) of thoracic spinal cord in adult rats. We made intracellular and extracellular recordings at L5 (below HX) in response to electrical stimulation of contralateral white matter above (T6) and below (L1) HX. Responses from T6 displayed reduced amplitude, increased latency and elevated stimulus threshold in the fibers across from HX, beginning 1-2 weeks after HX. Ultrastructural analysis revealed demyelination of intact axons contralateral to the HX, with a time course similar to the conduction changes. Behavioral studies indicated partial recovery which arrested when conduction deficits began. These findings suggest a chronic pathological state in intact fibers and necessity for prompt treatment to minimize it
Causal Loop Quantum Gravity and Cosmological Solutions
We shall present here the causal interpretation of canonical quantum gravity
in terms of new variables. Then we shall apply it to the minisuperspace of
cosmology. A vacuum solution of quantum cosmology is obtained and the Bohmian
trajectory is investigated. At the end a coherent state with matter is
considered in the cosmological model.Comment: 22 pages, 6 figure
A first experimental test of de Broglie-Bohm theory against standard quantum mechanics
De Broglie - Bohm (dBB) theory is a deterministic theory, built for
reproducing almost all Quantum Mechanics (QM) predictions, where position plays
the role of a hidden variable. It was recently shown that different coincidence
patterns are predicted by QM and dBB when a double slit experiment is realised
under specific conditions and, therefore, an experiment can test the two
theories. In this letter we present the first realisation of such a double slit
experiment by using correlated photons produced in type I Parametric Down
Conversion. Our results confirm QM contradicting dBB predictions
Some Properties of R\'{e}nyi Entropy over Countably Infinite Alphabets
In this paper we study certain properties of R\'{e}nyi entropy functionals
on the space of probability distributions over
. Primarily, continuity and convergence issues are addressed.
Some properties shown parallel those known in the finite alphabet case, while
others illustrate a quite different behaviour of R\'enyi entropy in the
infinite case. In particular, it is shown that, for any distribution and any , there exists a sequence of distributions
converging to with respect to the total variation
distance, such that .Comment: 13 pages (single-column
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