944 research outputs found
Detecting relic gravitational waves in the CMB: A statistical bias
Analyzing the imprint of relic gravitational waves (RGWs) on the cosmic
microwave background (CMB) power spectra provides a way to determine the signal
of RGWs. In this Letter, we discuss a statistical bias, which could exist in
the data analysis and has the tendency to overlook the RGWs. We also explain
why this bias exists, and how to avoid it.Comment: 4 pages, 1 figur
Retinal S-antigen Th1 cell epitope mapping in patients with Behcet's disease
Background - Retinal S-antigen (S-Ag) is a most characterized autoantigen of autoimmune uveitis. The recognized immunodominant epitope of human S-Ag in patients with uveitis has not been identified. In this study, we selected certain patients with active uveitis to map the Th1 cell epitope spectrum of human S-Ag in Behcet's disease(BD). Methods - Blood samples were taken from eight active BD patients who showed an immune response to 40 mixed overlapping peptides spanning the entire sequence of human S-Ag. Peripheral blood mononuclear cells were isolated and stimulated with single S-Ag peptide at 5 mu g/ml or 20 mu g/ml. Single-cell immune responses were measured by IFN-gamma ELIspot assay. Results - BD patients heterogeneously responded to the S-Ag peptides at two concentrations. In general, the responses to 5 mu g/ml peptides were slightly stronger than those to 20 mu g/ml peptides, while the maximum SFC frequency to single peptide at the two concentrations was similar. Several peptides including P31, P35 and P40 induced a prominent response, with the frequency of S-Ag specific cells being about 0.007%. Significant reactivity pattern shift was noted in patients with different disease courses. Conclusions - Certain active BD patients have S-Ag specific Th1 cells with a low frequency. The S-Ag epitope specificity between patients is highly heterogeneous, and varies with the uveitis cours
Detection of relic gravitational waves in the CMB: Prospects for CMBPol mission
Detection of relic gravitational waves, through their imprint in the cosmic
microwave background radiation, is one of the most important tasks for the
planned CMBPol mission. In the simplest viable theoretical models the
gravitational wave background is characterized by two parameters, the
tensor-to-scalar ratio and the tensor spectral index . In this paper,
we analyze the potential joint constraints on these two parameters, and
, using the potential observations of the CMBPol mission, which is
expected to detect the relic gravitational waves if . The
influence of the contaminations, including cosmic weak lensing, various
foreground emissions, and systematical errors, is discussed.Comment: 26 pages, 19 figures, 4 tables; JCAP in pres
Interacting Ricci Dark Energy and its Statefinder Description
In this paper we have considered an interacting Ricci dark energy in flat FRW
universe. We have reconstructed the Hubble's parameter under this interaction.
Also, we have investigated the statefinder diagnostics. It has been revealed
that the equation of state parameter behaves like quintessence in this
interaction and from the statefinder diagnostics it has been concluded that the
interacting Ricci dark energy interpolates between dust and CDM stages
of the universe.Comment: 9 pages, 3 figure
Influence of microwave fields on the electron transport through a quantum dot in the presence of a direct tunneling between leads
We consider the time-dependent electron transport through a quantum dot
coupled to two leads in the presence of the additional over-dot (bridge)
tunneling channel. By using the evolution operator method together with the
wide-band limit approximation we derived the analytical formulaes for the
quantum dot charge and current flowing in the system. The influence of the
external microwave field on the time-average quantum dot charge, the current
and the derivatives of the average current with respect to the gate and
source-drain voltages has been investigated for a wide range of parameters.Comment: 28 Pages, 11 Postscript figure
A step towards testing general relativity using weak gravitational lensing and redshift surveys
Using the linear theory of perturbations in General Relativity, we express a
set of consistency relations that can be observationally tested with current
and future large scale structure surveys. We then outline a stringent
model-independent program to test gravity on cosmological scales. We illustrate
the feasibility of such a program by jointly using several observables like
peculiar velocities, galaxy clustering and weak gravitational lensing. After
addressing possible observational or astrophysical caveats like galaxy bias and
redshift uncertainties, we forecast in particular how well one can predict the
lensing signal from a cosmic shear survey using an over-lapping galaxy survey.
We finally discuss the specific physics probed this way and illustrate how
gravity models would fail such a test.Comment: 12 pages, 10 figure
MicroRNA profile of Marek's disease virus-transformed T-cell line MSB-1: predominance of virus-encoded microRNAs
Research over the last few years has demonstrated the increasing role of microRNAs (miRNAs) as major regulators of gene expression in diverse cellular processes and diseases. Several viruses, particularly herpesviruses, also use the miRNA pathway of gene regulation by encoding their own miRNAs. Marek's disease (MD) is a widespread lymphomatous neoplastic disease of poultry caused by the highly contagious Marek's disease virus type 1 (MDV-1). Recent studies using virus-infected chicken embryo fibroblasts have identified at least eight miRNAs that map to the R(L)/R(S) region of the MDV genome. Since MDV is a lymphotropic virus that induces T-cell lymphomas, analysis of the miRNA profile in T-cell lymphoma would be more relevant for examining their role in oncogenesis. We determined the viral and host miRNAs expressed in MSB-1, a lymphoblastoid cell line established from an MDV-induced lymphoma of the spleen. In this paper, we report the identification of 13 MDV-1-encoded miRNAs (12 by direct cloning and 1 by Northern blotting) from MSB-1 cells. These miRNAs, five of which are novel MDV-1 miRNAs, map to the Meq and latency-associated transcript regions of the MDV genome. Furthermore, we show that miRNAs encoded by MDV-1 and the coinfected MDV-2 accounted for >60% of the 5,099 sequences of the MSB-1 âmiRNAome.â Several chicken miRNAs, some of which are known to be associated with cancer, were also cloned from MSB-1 cells. High levels of expression of MDV-1-encoded miRNAs and potentially oncogenic host miRNAs suggest that miRNAs may have major roles in MDV pathogenesis and neoplastic transformation
Electrochemical capacitance of a leaky nano-capacitor
We report a detailed theoretical investigation on electrochemical capacitance
of a nanoscale capacitor where there is a DC coupling between the two
conductors. For this ``leaky'' quantum capacitor, we have derived general
analytic expressions of the linear and second order nonlinear electrochemical
capacitance within a first principles quantum theory in the discrete potential
approximation. Linear and nonlinear capacitance coefficients are also derived
in a self-consistent manner without the latter approximation and the
self-consistent analysis is suitable for numerical calculations. At linear
order, the full quantum formula improves the semiclassical analysis in the
tunneling regime. At nonlinear order which has not been studied before for
leaky capacitors, the nonlinear capacitance and nonlinear nonequilibrium charge
show interesting behavior. Our theory allows the investigation of crossover of
capacitance from a full quantum to classical regimes as the distance between
the two conductors is changed
Reverse-Engineering a Transcriptional Enhancer: A Case Study in Drosophila
Abstract Enhancers, or cis-regulatory elements, are the principal determinants of spatiotemporal patterning of gene expression. For reasons of clinical and research utility, it is desirable to build customized enhancers that drive novel gene expression patterns, but currently, we largely rely on âfoundâ genomic elements. Synthetic enhancers, assembled from transcription factor binding sites taken from natural signal-regulated enhancers, generally fail to behave like their wild-type counterparts when placed in transgenic animals, suggesting that important aspects of enhancer function are still unexplored. As a step toward the creation of a truly synthetic regulatory element, we have undertaken an extensive structureâfunction study of an enhancer of the Drosophila decapentaplegic (dpp) gene that drives expression in the developing visceral mesoderm (VM). Although considerable past efforts have been made to dissect the dppVM enhancer, transgenic experiments presented here indicate that its activity cannot be explained by the known regulators alone. dppVM contains multiple, previously uncharacterized, regulatory sites, some of which exhibit functional redundancy. The results presented here suggest that even the best-studied enhancers must be further dissected before they can be fully understood, and before faithful synthetic elements based on them can be created. Implications for developmental genetics, mathematical modeling, and therapeutic applications are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63213/1/ten.tea.2008.0074.pd
Global well-posedness and scattering for the energy-critical, defocusing Hartree equation in
Using the same induction on energy argument in both frequency space and
spatial space simultaneously as in \cite{CKSTT07}, \cite{RyV05} and
\cite{Vi05}, we obtain global well-posedness and scattering of energy solutions
of defocusing energy-critical nonlinear Hartree equation in (), which removes the radial assumption on the data in
\cite{MiXZ07a}. The new ingredients are that we use a modified long time
perturbation theory to obtain the frequency localization (Proposition
\ref{freqdelocaimplystbound} and Corollary \ref{frequencylocalization}) of the
minimal energy blow up solutions, which can not be obtained from the classical
long time perturbation and bilinear estimate and that we obtain the spatial
concentration of minimal energy blow up solution after proving that
-norm of minimal energy blow up solutions is bounded from
below, the -norm is larger than the potential energy.Comment: 41page
- âŠ