290,456 research outputs found
Stereoisomer libraries: Total synthesis of all 16 stereoisomers of the pine sawfly sex pheromone by a fluorous mixture-synthesis approach
All 16 stereoisomers of the sex pheromone of pine sawfly (3,7,11-trimethylundecanol propanoate ester) have been synthesized on a 10- to 20-mg scale by a split-parallel fluorous mixture-synthesis approach. Spectral data obtained for all 32 compounds (16 alcohols and the corresponding propionates) matched well with published data, thereby validating the fluorous-tag encoding of diastereoisomers. This fluorous-tag encoding method is recommended for the efficient synthesis of multiple stereoisomers for spectroscopic studies, biological tests, or other structure-function relationships
A Modified Approach to Single-Spin Detection Using Magnetic Resonance Force Microscopy
The magnetic moment of a single spin interacting with a cantilever in
magnetic resonance force microscopy (MRFM) experiences quantum jumps in
orientation rather than smooth oscillations. These jumps cannot be detected by
a conventional MRFM based on observation of driven resonant oscillations of a
cantilever. In this paper, we propose a method which will allow detection of
the magnetic signal from a single spin using a modification of a conventional
MRFM. We estimate the opportunity to detect the magnetic signal from a single
proton.Comment: 4 pages LaTex, 4 figures in GIF forma
Limits to phase resolution in matter wave interferometry
We study the quantum dynamics of a two-mode Bose-Einstein condensate in a
time-dependent symmetric double-well potential using analytical and numerical
methods. The effects of internal degrees of freedom on the visibility of
interference fringes during a stage of ballistic expansion are investigated
varying particle number, nonlinear interaction sign and strength as well as
tunneling coupling. Expressions for the phase resolution are derived and the
possible enhancement due to squeezing is discussed. In particular, the role of
the superfluid - Mott insulator cross-over and its analog for attractive
interactions is recognized.Comment: 10 pages, 9 figure
Mass Hierarchy Resolution in Reactor Anti-neutrino Experiments: Parameter Degeneracies and Detector Energy Response
Determination of the neutrino mass hierarchy using a reactor neutrino
experiment at 60 km is analyzed. Such a measurement is challenging due to
the finite detector resolution, the absolute energy scale calibration, as well
as the degeneracies caused by current experimental uncertainty of . The standard method is compared with a proposed Fourier
transformation method. In addition, we show that for such a measurement to
succeed, one must understand the non-linearity of the detector energy scale at
the level of a few tenths of percent.Comment: 7 pages, 6 figures, accepted by PR
Bayesian Non-Exhaustive Classification A Case Study: Online Name Disambiguation using Temporal Record Streams
The name entity disambiguation task aims to partition the records of multiple
real-life persons so that each partition contains records pertaining to a
unique person. Most of the existing solutions for this task operate in a batch
mode, where all records to be disambiguated are initially available to the
algorithm. However, more realistic settings require that the name
disambiguation task be performed in an online fashion, in addition to, being
able to identify records of new ambiguous entities having no preexisting
records. In this work, we propose a Bayesian non-exhaustive classification
framework for solving online name disambiguation task. Our proposed method uses
a Dirichlet process prior with a Normal * Normal * Inverse Wishart data model
which enables identification of new ambiguous entities who have no records in
the training data. For online classification, we use one sweep Gibbs sampler
which is very efficient and effective. As a case study we consider
bibliographic data in a temporal stream format and disambiguate authors by
partitioning their papers into homogeneous groups. Our experimental results
demonstrate that the proposed method is better than existing methods for
performing online name disambiguation task.Comment: to appear in CIKM 201
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