2,508 research outputs found
Measurement of the D-D fusion neutron energy spectrum and variation of the peak width with plasma ion temperature
and disposal, in whole or in part by or for the United States govern-ment is permitted. By acceptance of this article, the publisher and/or recipient ac-knowledges the U.S. Government's right to retain a non-exclusive, royalty-free license in and to any copyright covering this paper. 1 Measurement of the d-d fusion neutron energy spectrum and variation of the peak width with plasma ion temperature W. A. Fisher*, S. H. Chen*, D. Gwinnt, R. R. Parkert We report a set of neutron spectrum measurements made at the Alcator C tokamak under ohmic heating conditions. It has been found that the width of the D-D fusion neutron peak increases with the plasma ion temperature consistent with the theoretical prediction. In particular the neutron spectra resulting from the sum of many plasma discharges with ion temperatures of 780 eV and 1050 eV have been ob-tained. The width for the 780 eV case is 64 +9,-11 keV and that of the 1050 eV case, 81 +10,-14 keV FWHM, corresponding to ion tempera-tures of 740 eV and 1190 eV respectively
Deep finger texture learning for verifying people
Finger Texture (FT) is currently attracting significant attentions in the area of human recognition. Finger texture covers the area between the lower knuckle of the finger and the upper phalanx before the fingerprint. It involves rich features which can be efficiently used as a biometric characteristic. In this paper, we contribute to this growing area by proposing a new verification
approach, i.e., Deep Finger Texture Learning (DFTL). To the best of our knowledge, this is the first time that deep learning is employed for recognizing people by using the FT characteristic. Four databases have been used to evaluate the proposed method: the Hong Kong Polytechnic University Contact-free 3D/2D (PolyU2D), Indian Institute of Technology Delhi (IITD), CASIA Blue spectral (CASIA-BLU) corresponding to spectral 460nm and CASIA White spectral (CASIA-WHT) from the CASIA Multi-Spectral images database. The obtained results have shown superior performance compared with recent literature. The Verification Accuracies (VAs) have attained 100%, 98.65%, 100% and 98% for the four databases of PolyU2D, IITD, CASIA-BLU and CASIA-WHT, respectively
Generating dynamic higher-order Markov models in web usage mining
Markov models have been widely used for modelling users’ web navigation behaviour. In previous work we have presented a dynamic clustering-based Markov model that accurately represents second-order transition probabilities given by a collection of navigation sessions. Herein, we propose a generalisation of the method that takes into account higher-order conditional probabilities. The method makes use of the state cloning concept together with a clustering technique to separate the navigation paths that reveal differences in the conditional probabilities. We report on experiments conducted with three real world data sets. The results show that some pages require a long history to understand the users choice of link, while others require only a short history. We also show that the number of additional states induced by the method can be controlled through a probability threshold parameter
Two Unrelated 8-Vinyl Reductases Ensure Production of Mature Chlorophylls in Acaryochloris marina
The major photopigment of the cyanobacterium
Acaryochloris marina
is chlorophyll
d
, while its direct biosynthetic precursor,
chlorophyll
a
, is also present in the cell. These pigments, along with the majority of chlorophylls utilized by oxygenic pho-
totrophs, carry an ethyl group at the C-8 position of the molecule, having undergone reduction of a vinyl group during biosyn-
thesis. Two unrelated classes of 8-vinyl reductase involved in the biosynthesis of chlorophylls are known to exist, BciA and BciB.
The genome of
Acaryochloris marina
contains open reading frames (ORFs) encoding proteins displaying high sequence similarity to BciA or BciB, although they are annotated as genes involved in transcriptional control (
nmrA
) and methanogenesis (
frhB
),
respectively. These genes were introduced into an 8-vinyl chlorophyll
a
-producing
delta
bciB
strain of
Synechocystis
sp. strain PCC
6803, and both were shown to restore synthesis of the pigment with an ethyl group at C-8, demonstrating their activities as 8-vinyl reductases. We propose that
nmrA
and
frhB
be reassigned as
bciA
and
bciB
, respectively; transcript and proteomic analysis of
Acaryochloris marina
reveal that both
bciA
and
bciB
are expressed and their encoded proteins are present in the cell, possibly in
order to ensure that all synthesized chlorophyll pigment carries an ethyl group at C-8. Potential reasons for the presence of two
8-vinyl reductases in this strain, which is unique for cyanobacteria, are discussed
Partially spin polarized quantum Hall effect in the filling factor range 1/3 < nu < 2/5
The residual interaction between composite fermions (CFs) can express itself
through higher order fractional Hall effect. With the help of diagonalization
in a truncated composite fermion basis of low-energy many-body states, we
predict that quantum Hall effect with partial spin polarization is possible at
several fractions between and . The estimated excitation
gaps are approximately two orders of magnitude smaller than the gap at
, confirming that the inter-CF interaction is extremely weak in higher
CF levels.Comment: 4 pages, 3 figure
An Asymmetric Cone Model for Halo Coronal Mass Ejections
Due to projection effects, coronagraphic observations cannot uniquely
determine parameters relevant to the geoeffectiveness of CMEs, such as the true
propagation speed, width, or source location. The Cone Model for Coronal Mass
Ejections (CMEs) has been studied in this respect and it could be used to
obtain these parameters. There are evidences that some CMEs initiate from a
flux-rope topology. It seems that these CMEs should be elongated along the
flux-rope axis and the cross section of the cone base should be rather
elliptical than circular. In the present paper we applied an asymmetric cone
model to get the real space parameters of frontsided halo CMEs (HCMEs) recorded
by SOHO/LASCO coronagraphs in 2002. The cone model parameters are generated
through a fitting procedure to the projected speeds measured at different
position angles on the plane of the sky. We consider models with the apex of
the cone located at the center and surface of the Sun. The results are compared
to the standard symmetric cone model
Horava-Lifshitz Dark Energy
We formulate Horava-Lifshitz cosmology with an additional scalar field that
leads to an effective dark energy sector. We find that, due to the inherited
features from the gravitational background, Horava-Lifshitz dark energy
naturally presents very interesting behaviors, possessing a varying
equation-of-state parameter, exhibiting phantom behavior and allowing for a
realization of the phantom divide crossing. In addition, Horava-Lifshitz dark
energy guarantees for a bounce at small scale factors and it may trigger the
turnaround at large scale factors, leading naturally to cyclic cosmology.Comment: 17 pages, no figures, version published at EJP
Adhesion-induced phase separation of multiple species of membrane junctions
A theory is presented for the membrane junction separation induced by the
adhesion between two biomimetic membranes that contain two different types of
anchored junctions (receptor/ligand complexes). The analysis shows that several
mechanisms contribute to the membrane junction separation. These mechanisms
include (i) the height difference between type-1 and type-2 junctions is the
main factor which drives the junction separation, (ii) when type-1 and type-2
junctions have different rigidities against stretch and compression, the
``softer'' junctions are the ``favored'' species, and the aggregation of the
softer junction can occur, (iii) the elasticity of the membranes mediates a
non-local interaction between the junctions, (iv) the thermally activated shape
fluctuations of the membranes also contribute to the junction separation by
inducing another non-local interaction between the junctions and renormalizing
the binding energy of the junctions. The combined effect of these mechanisms is
that when junction separation occurs, the system separates into two domains
with different relative and total junction densities.Comment: 23 pages, 6 figure
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