179 research outputs found
Finite Blocklength Analysis of Gaussian Random Coding in AWGN Channels under Covert Constraint
This paper considers the achievability and converse bounds on the maximal
channel coding rate at a given blocklength and error probability over AWGN
channels. The problem stems from covert communication with Gaussian codewords.
By re-visiting [18], we first present new and more general achievability bounds
for random coding schemes under maximal or average probability of error
requirements. Such general bounds are then applied to covert communication in
AWGN channels where codewords are generated from Gaussian distribution while
meeting the maximal power constraint. Further comparison is made between the
new achievability bounds and existing one with deterministic codebooks.Comment: 18 page
Finite Blocklength Analysis of Gaussian Random coding in AWGN Channels under Covert constraints II: A Viewpoint of Total Variation Distance
Covert communication over an additive white Gaussian noise (AWGN) channel
with finite block length is investigated in this paper. The attention is on the
covert criterion, which has not been considered in finite block length
circumstance. As an accurate quantity metric of discrimination, the variation
distance with given finite block length n and signal-noise ratio (snr) is
obtained. We give both its analytic solution and expansions which can be easily
evaluated. It is shown that K-L distance, which is frequently adopted as the
metric of discrimination at the adversary in asymptotic regime, is not
convincing in finite block length regime compared with the total variation
distance. Moreover, the convergence rate of the total variation with different
snr is analyzed when the block length tends to infinity. The results will be
very helpful for understanding the behavior of the total variation distance and
practical covert communication
The First and Second Order Asymptotics of Covert Communication over AWGN Channels
This paper investigates the asymptotics of the maximal throughput of
communication over AWGN channels by channel uses under a covert constraint
in terms of an upper bound of Kullback-Leibler divergence (KL
divergence). It is shown that the first and second order asymptotics of the
maximal throughput are and
, respectively.
The technique we use in the achievability is quasi--neighborhood
notion from information geometry. We prove that if the generating distribution
of the codebook is close to Dirac measure in the weak sense, then the
corresponding output distribution at the adversary satisfies covert constraint
in terms of most common divergences. This helps link the local differential
geometry of the distribution of noise with covert constraint. For the converse,
the optimality of Gaussian distribution for minimizing KL divergence under
second order moment constraint is extended from dimension to dimension .
It helps to establish the upper bound on the average power of the code to
satisfy the covert constraint, which further leads to the direct converse bound
in terms of covert metric
Wnt5a regulates dental follicle stem/progenitor cells of the periodontium
Introduction
Dental follicle gives rise to one or several tissues of the periodontium including the periodontal ligament, cementum and/or alveolar bone. Whether Wnt5a is expressed in the postnatal periodontium or regulates dental follicle stem/progenitor cells is unknown.
Methods
Dental follicle stem/progenitor cells were isolated from postnatal day 1 (p1) to p11 from rat mandibular first molars. Immunolocalization mapped Wnt5a expression in the alveolar bone, periodontal ligament, and the developing ameloblast and odontoblast layers. Mononucleated and adherent cells were isolated from p7 dental follicle. Wnt5a was overexpressed in dental follicle stem/progenitor cells to study their proliferation, osteogenic differentiation and migration behavior, with subpopulations of native dental follicle stem/progenitor cells as controls, using real-time PCR (Taqman), Lenti-viral transfection, Western blotting and immunofluorescence.
Results
Wnt5a was expressed consistently in p1 to p11 rat peridontium. Native, p7 dental follicle stem/progenitor cells had modest ability to mineralize in the tested 14 days. Even in chemically defined osteogenesis medium, dental follicle stem/progenitor cells only showed modest mineralization. Upon addition of 300 ng/mL Wnt5a protein in osteogenesis medium, dental follicle stem/progenitor cells displayed mineralization that was still unremarkable. Chemically induced or Wnt5a-induced mineralization of dental follicle cells only occurred sparsely. Combination of Wnt5a with 100 ng/mL BMP2 finally prompted dental follicle stem/progenitor cells to produce robust mineralization with elevated expression of Runx2, alkaline phosphatase, collagen 1α1 and osteocalcin. Thus, native dental follicle stem/progenitor cells or some of their fractions may be somewhat modest in mineralization. Strikingly, Wnt5a protein significantly augmented RANKL ligand, suggesting putative regulatory roles of dental follicle stem/progenitor cells for the monocyte/osteoclast lineage and potential involvement in alveolar bone remodeling and/or resorption. P-Jnk1/2 was activated in Wnt5a overexpressed dental follicle cells; conversely, exposure to SP600125, a c-Jun N-terminal kinase (JNK) inhibitor attenuated Runx2, collagen 1α1 and osteocalcin expression either in the presence or absence of Wnt5a. Wnt5a overexpression in dental follicle stem/progenitor cells significantly reduced their proliferation rates, but robustly augmented their migration capacity.
Conclusions
These findings provide a glimpse of Wnt5a’s putative roles in dental follicle stem/progenitor cells and the periodontium with implications in periodontal disease, tooth eruption, dental implant bone healing and orthodontic tooth movement
Genetic diversity and association of EST-SSR and SCoT markers with rust traits in orchardgrass (Dactylis glomerata L.)
This article belongs to the Section Molecular Diversity.Orchardgrass (Dactylis glomerata L.), is a well-known perennial forage species; however, rust diseases have caused a noticeable reduction in the quality and production of orchardgrass. In this study, genetic diversity was assessed and the marker-trait associations for rust were examined using 18 EST-SSR and 21 SCoT markers in 75 orchardgrass accessions. A high level of genetic diversity was detected in orchardgrass with an average genetic diversity index of 0.369. For the EST-SSR and SCoT markers, 164 and 289 total bands were obtained, of which 148 (90.24%) and 272 (94.12%) were polymorphic, respectively. Results from an AMOVA analysis showed that more genetic variance existed within populations (87.57%) than among populations (12.43%). Using a parameter marker index, the efficiencies of the EST-SSR and SCoT markers were compared to show that SCoTs have higher marker efficiency (8.07) than EST-SSRs (4.82). The results of a UPGMA cluster analysis and a STRUCTURE analysis were both correlated with the geographic distribution of the orchardgrass accessions. Linkage disequilibrium analysis revealed an average r2 of 0.1627 across all band pairs, indicating a high extent of linkage disequilibrium in the material. An association analysis between the rust trait and 410 bands from the EST-SSR and SCoT markers using TASSEL software revealed 20 band panels were associated with the rust trait in both 2011 and 2012. The 20 bands obtained from association analysis could be used in breeding programs for lineage selection to prevent great losses of orchardgrass caused by rust, and provide valuable information for further association mapping using this collection of orchardgrass.This work was supported by the National Basic Research Program of China (973 Program) (2014CB138705) and the National Natural Science Foundation of China, NSFC (31101760).Peer reviewe
The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe
The preponderance of matter over antimatter in the early Universe, the
dynamics of the supernova bursts that produced the heavy elements necessary for
life and whether protons eventually decay --- these mysteries at the forefront
of particle physics and astrophysics are key to understanding the early
evolution of our Universe, its current state and its eventual fate. The
Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed
plan for a world-class experiment dedicated to addressing these questions. LBNE
is conceived around three central components: (1) a new, high-intensity
neutrino source generated from a megawatt-class proton accelerator at Fermi
National Accelerator Laboratory, (2) a near neutrino detector just downstream
of the source, and (3) a massive liquid argon time-projection chamber deployed
as a far detector deep underground at the Sanford Underground Research
Facility. This facility, located at the site of the former Homestake Mine in
Lead, South Dakota, is approximately 1,300 km from the neutrino source at
Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino
charge-parity symmetry violation and mass ordering effects. This ambitious yet
cost-effective design incorporates scalability and flexibility and can
accommodate a variety of upgrades and contributions. With its exceptional
combination of experimental configuration, technical capabilities, and
potential for transformative discoveries, LBNE promises to be a vital facility
for the field of particle physics worldwide, providing physicists from around
the globe with opportunities to collaborate in a twenty to thirty year program
of exciting science. In this document we provide a comprehensive overview of
LBNE's scientific objectives, its place in the landscape of neutrino physics
worldwide, the technologies it will incorporate and the capabilities it will
possess.Comment: Major update of previous version. This is the reference document for
LBNE science program and current status. Chapters 1, 3, and 9 provide a
comprehensive overview of LBNE's scientific objectives, its place in the
landscape of neutrino physics worldwide, the technologies it will incorporate
and the capabilities it will possess. 288 pages, 116 figure
Increased Levels of BAFF and APRIL Related to Human Active Pulmonary Tuberculosis
BACKGROUND: Despite great efforts to improve diagnosis and treatment, tuberculosis (TB) remains a major health problem worldwide, especially in developing countries. Lack of concrete immune markers is still the obstacle to properly evaluate active TB. Therefore, identification of more validated biomarkers and phenotypic signatures is imperative. In particular, T cell-related biomarkers are more significant. METHODOLOGY: To understand the nature of CD4(+) T cell-derived signatures involved in infection and disease development, we examined and analyzed whole genome expression profiles of purified CD4(+) T cells from healthy individuals (HD), two distinct populations with latent infection (with low or high IFN-γ levels, LTB(L)/LTB(H)) and untreated TB patients. Following, we validated the expression profiles of genes in the peripheral CD4(+) T cells from each group and examined secretion levels of distinct cytokines in serum and pleural effusion. PRINCIPAL FINDINGS: Our bio-informatic analyses indicate that the two latent populations and clinical TB patients possess distinct CD4(+) T cell gene expression profiles. Furthermore, The mRNA and protein expression levels of B cell activating factor (BAFF), which belongs to the TNF family, and a proliferation-inducing ligand (APRIL) were markedly up-regulated at the disease stage. In particular, the dramatic enhancement of BAFF and APRIL in the pleural effusion of patients with tuberculosis pleurisy suggests that these proteins may present disease status. In addition, we found that the BAFF/APRIL system was closely related to the Th1 immune response. Our study delineates previously unreported roles of BAFF and APRIL in the development of tuberculosis, and these findings have implications for the diagnosis of the disease. Our study also identifies a number of transcriptional signatures in CD4(+) T cells that have the potential to be utilized as diagnostic and prognostic tools to combat the tuberculosis epidemic
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