556 research outputs found
A Maxwell-vector p-wave holographic superconductor in a particular background AdS black hole metric
We study the p-wave holographic superconductor for AdS black holes with
planar event horizon topology for a particular Lovelock gravity, in which the
action is characterized by a self-interacting scalar field nonminimally coupled
to the gravity theory which is labeled by an integer . As the Lovelock
theory of gravity is the most general metric theory of gravity based on the
fundamental assumptions of general relativity, it is a desirable theory to
describe the higher dimensional spacetime geometry. The present work is devoted
to studying the properties of the p-wave holographic superconductor by
including a Maxwell field which nonminimally couples to a complex vector field
in a higher dimensional background metric. In the probe limit, we find that the
critical temperature decreases with the increase of the index of the
background black hole metric, which shows that a larger makes it harder for
the condensation to form. We also observe that the index affects the
conductivity and the gap frequency of the holographic superconductors.Comment: 14 pages, 6 figure
New bounds for -Symbol Distances of Matrix Product Codes
Matrix product codes are generalizations of some well-known constructions of
codes, such as Reed-Muller codes, -construction, etc. Recently, a
bound for the symbol-pair distance of a matrix product code was given in
\cite{LEL}, and new families of MDS symbol-pair codes were constructed by using
this bound. In this paper, we generalize this bound to the -symbol distance
of a matrix product code and determine all minimum -symbol distances of
Reed-Muller codes. We also give a bound for the minimum -symbol distance of
codes obtained from the -construction, and use this bound to
construct some -linear -symbol almost MDS codes with arbitrary
length. All the minimum -symbol distances of -linear codes and
-linear codes for are determined. Some examples are
presented to illustrate these results
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Salmonella produce microRNA-like RNA fragment Sal-1 in the infected cells to facilitate intracellular survival.
Salmonella have developed a sophisticated machinery to evade immune clearance and promote survival in the infected cells. Previous studies were mostly focused on either bacteria itself or host cells, the interaction mechanism of host-pathogen awaits further exploration. In the present study, we show that Salmonella can exploit mammalian cell non-classical microRNA processing machinery to further process bacterial small non-coding RNAs into microRNA-like fragments. Sal-1, one such fragment with the highest copy number in the infected cells, is derived from Salmonella 5-leader of the ribosomal RNA transcript and has a stem structure-containing precursor. Processing of Sal-1 precursors to mature Sal-1 is dependent on host cell Argonaute 2 (AGO2) but not Dicer. Functionally, depleting cellular Sal-1 strongly renders the Salmonella bacteria less resistant to the host defenses both in vitro and in vivo. In conclusion, we demonstrate a novel strategy for Salmonella evading the host immune clearance, in which Salmonella produce microRNA-like functional RNA fragments to establish a microenvironment facilitating bacterial survival
Refractive index in generalized superconductors with Born-Infeld electrodynamics
We investigate, in the probe limit, the negative refraction in the
generalized superconductors with the Born-Infeld electrodynamics. We observe
that the system has a negative Depine-Lakhtakia index in the superconducting
phase at small frequencies and the greater the Born-Infeld corrections the
larger the range of frequencies or the range of temperatures for which the
negative refraction occurs. Furthermore, we find that the tunable Born-Infeld
parameter can be used to improve the propagation of light in the holographic
setup. Our analysis indicates that the Born-Infeld electrodynamics plays an
important role in determining the optical properties of the boundary theory.Comment: 13 pages, 6 figure
A RFID-Based Monitoring System for Characterization of Perching Behaviors of Individual Poultry
Perching is a natural behavior of poultry. However, it is difficult to distinguish individual birds in a large group in order to relate perching behavior to health condition or productivity. To enable such research, this study developed and validated a radio frequency identification (RFID)-based automated perching monitoring system (APMS) for characterizing individual perching behaviors of group-housed poultry. The APMS consisted of a RFID module, a load cell module, and a round wooden perch. The RFID module was comprised of a high-frequency RFID reader, three customized rectangular antennas, and multiple RFID transponders. The load cell module was comprised of a data acquisition system and two load cells supporting the two ends of the perch. Daily number of perch visits (PV) and perching duration (PD) of individual birds were used to delineate perching behavior. Three identical experimental pens, five hens per pen, were equipped with the monitoring system. Two RFID transponders were attached to each hen (one per leg) and a distinct color was marked on the bird‘s head for video or visual identification. Performance of the APMS was validated by comparing the system outputs with manual observation/labeling over an entire day. Sensitivity and specificity of the system were shown to improve from 97.77% and 99.88%, respectively, when using only the RFID module, to 99.83% and 99.93%, respectively, when incorporating weight information from the load cell module. This study revealed that the APMS has an excellent performance in measuring perching behaviors of individual birds in a group. The APMS offers great potentials for delineating differences in perching behavior among hens with different social status or health conditions in a group setting
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