1,205 research outputs found
Vortex solutions of a Maxwell-Chern-Simons field coupled to four-fermion theory
We find the static vortex solutions of the model of Maxwell-Chern-Simons
gauge field coupled to a (2+1)-dimensional four-fermion theory. Especially, we
introduce two matter currents coupled to the gauge field minimally: the
electromagnetic current and a topological current associated with the
electromagnetic current. Unlike other Chern-Simons solitons the N-soliton
solution of this theory has binding energy and the stability of the solutions
is maintained by the charge conservation laws.Comment: 7 pages, harvmac, To be published in Phys. Rev. D5
Modeling the Expected Performance of the REgolith X-ray Imaging Spectrometer (REXIS)
OSIRIS-REx is the third spacecraft in the NASA New Frontiers Program and is
planned for launch in 2016. OSIRIS-REx will orbit the near-Earth asteroid
(101955) Bennu, characterize it, and return a sample of the asteroid's regolith
back to Earth. The Regolith X-ray Imaging Spectrometer (REXIS) is an instrument
on OSIRIS-REx designed and built by students at MIT and Harvard. The purpose of
REXIS is to collect and image sun-induced fluorescent X-rays emitted by Bennu,
thereby providing spectroscopic information related to the elemental makeup of
the asteroid regolith and the distribution of features over its surface.
Telescopic reflectance spectra suggest a CI or CM chondrite analog meteorite
class for Bennu, where this primitive nature strongly motivates its study. A
number of factors, however, will influence the generation, measurement, and
interpretation of the X-ray spectra measured by REXIS. These include: the
compositional nature and heterogeneity of Bennu, the time-variable Solar state,
X-ray detector characteristics, and geometric parameters for the observations.
In this paper, we will explore how these variables influence the precision to
which REXIS can measure Bennu's surface composition. By modeling the
aforementioned factors, we place bounds on the expected performance of REXIS
and its ability to ultimately place Bennu in an analog meteorite class.Comment: Presented at the SPIE Optics + Photonics Conference, 18 August 2014,
San Diego, C
The Dynamical Behaviors in (2+1)-Dimensional Gross-Neveu Model with a Thirring Interaction
We analyze (2+1)-dimensional Gross-Neveu model with a Thirring interaction,
where a vector-vector type four-fermi interaction is on equal terms with a
scalar-scalar type one. The Dyson-Schwinger equation for fermion self-energy
function is constructed up to next-to-leading order in 1/N expansion. We
determine the critical surface which is the boundary between a broken phase and
an unbroken one in () space. It is observed that the
critical behavior is mainly controlled by Gross-Neveu coupling and
the region of the broken phase is separated into two parts by the line
. The mass function is strongly
dependent upon the flavor number N for , while weakly for
, the critical flavor number
increases as Thirring coupling decreases. By driving the CJT
effective potential, we show that the broken phase is energetically preferred
to the symmetric one. We discuss the gauge dependence of the mass function and
the ultra-violet property of the composite operators.Comment: 19 pages, LaTex, 6 ps figure files(uuencoded in seperate file
The transcriptional response to Salmonella infection in swine
The porcine response to infection with Salmonella is the result of differential expression of host-specific genes. To characterize these alterations in gene expression, functional genomic analyses were performed on swine tissues following experimental inoculation of the pigs with Salmonella enterica serovars Choleraesuis and Typhimurium. Suppression subtractive hybridization and quantitative real-time RT-PCR revealed that the transcriptional profiles of the porcine response to the swine-adapted strain (Choleraesuis) and the non-host-adapted strain (Typhimurium) exhibit unique differences
Use of a Hanging-weight System for Isolated Renal Artery Occlusion
In hospitalized patients, over 50% of cases of acute kidney injury (AKI) are caused by renal ischemia 1-3. A recent study of hospitalized patients revealed that only a mild increase in serum creatinine levels (0.3 to 0.4 mg/dl) is associated with a 70% greater risk of death than in persons without any increase 1. Along these lines, surgical procedures requiring cross-clamping of the aorta and renal vessels are associated with a renal failure rates of up to 30% 4. Similarly, AKI after cardiac surgery occurs in over 10% of patients under normal circumstances and is associated with dramatic increases in mortality. AKI are also common complications after liver transplantation. At least 8-17% of patients end up requiring renal replacement therapy 5. Moreover, delayed graft function due to tubule cell injury during kidney transplantation is frequently related to ischemia-associated AKI 6. Moreover, AKI occurs in approximately 20% of patients suffering from sepsis 6.The occurrence of AKI is associated with dramatic increases of morbidity and mortality 1. Therapeutic approaches are very limited and the majority of interventional trials in AKI have failed in humans. Therefore, additional therapeutic modalities to prevent renal injury from ischemia are urgently needed 3, 7-9
Design rules for self-assembled block copolymer patterns using tiled templates
Directed self-assembly of block copolymers has been used for fabricating various nanoscale patterns, ranging from periodic lines to simple bends. However, assemblies of dense bends, junctions and line segments in a single pattern have not been achieved by using sparse templates, because no systematic template design methods for achieving such complex patterns existed. To direct a complex pattern by using a sparse template, the template needs to encode the key information contained in the final pattern, without being a simple copy of the pattern. Here we develop a set of topographic template tiles consisting of square lattices of posts with a restricted range of geometric features. The block copolymer patterns resulting from all tile arrangements are determined. By combining tiles in different ways, it is possible to predict a relatively simple template that will direct the formation of non-trivial block copolymer patterns, providing a new template design method for a complex block copolymer pattern.Samsung Scholarship FoundationSemiconductor Research CorporationTokyo Electron LimitedTaiwan Semicondcutor Manufacturing CompanyNational Science Foundation (U.S.) (Award DMR1234169
Concurrent Transcript and Protein Quantification in a Massive Single Cell Array Enables Population-Wide Observation of Oncogene Escape
Maxwell Chern-Simons Solitons from Type IIB String Theory
We study various three-dimensional supersymmetric Maxwell Chern-Simons
solitons by using type IIB brane configurations. We give a systematic
classification of soliton spectra such as topological BPS vortices and
nontopological vortices in supersymmetric Maxwell
Chern-Simons system via the branes of type IIB string theory. We identify the
brane configurations with the soliton spectra of the field theory and obtain a
nice agreement with field theory aspects. We also discuss possible brane
constructions for BPS domain wall solutions.Comment: 23 pages, Latex, 4 figures; (q_1,q_2)-string convention changed,
minor correction
Genetic and neuronal regulation of sleep by neuropeptide VF
Sleep is an essential and phylogenetically conserved behavioral state, but it remains unclear to what extent genes identified in invertebrates also regulate vertebrate sleep. RFamide-related neuropeptides have been shown to promote invertebrate sleep, and here we report that the vertebrate hypothalamic RFamide neuropeptide VF (NPVF) regulates sleep in the zebrafish, a diurnal vertebrate. We found that NPVF signaling and npvf-expressing neurons are both necessary and sufficient to promote sleep, that mature peptides derived from the NPVF preproprotein promote sleep in a synergistic manner, and that stimulation of npvf-expressing neurons induces neuronal activity levels consistent with normal sleep. These results identify NPVF signaling and npvf-expressing neurons as a novel vertebrate sleep-promoting system and suggest that RFamide neuropeptides participate in an ancient and central aspect of sleep control
Massive-Star Forming Infrared Loop around the Crab-like Supernova Remnant G54.1+0.3: Post Main-Sequence Triggered Star Formation?
We report the discovery of a star-forming loop around the young, Crab-like
supernova remnant (SNR) G54.1+0.3 using the AKARI infrared satellite. The loop
consists of at least eleven young stellar objects (YSOs) embedded in a
ring-like diffuse emission of radius ~1'. The YSOs are bright in the
mid-infrared and are also visible in the Spitzer Space Telescope Galactic plane
survey images. Their Spitzer colors are similar to those of class II YSOs in
[3.6]-[5.8] but significantly redder in [8]-[24], i.e., 0<[3.6]-[5.8]<1.2 and
5<[8]-[24]<9. Most of them have near-infrared counterparts in the 2MASS JHKs
images, and some of them have an optical counterpart too. Their JHKs colors and
magnitudes indicate that the YSOs are massive (<= 10 Msun) pre-main-sequence
stars at the same distance to the SNR, i.e., 8 kpc, which supports the
association of the star-forming loop with the SNR. The dereddened spectral
energy distributions are similar to eraly Herbig Be stars, which are early
B-type pre-main-sequence stars with inner disks that have been destroyed. The
confinement to a loop structure indicates that the YSOs are young, i.e., <= 2
Myr. We propose that their formation is triggered by the progenitor star of
G54.1+0.3, which has a mass of <= 15 Msun. The triggering must have occurred
near the end of the progenitor's life, possibly after it had evolved off the
main sequence.Comment: 6 pages, accepted for publication in the Astrophysical Journal
Letters; added a reference for section
- …