Nonlinear evolution of streaming instabilities in accreting protoplanetary disks

The streaming instability (SI) is one of the most promising candidates for triggering planetesimal formation by producing dense dust clumps that undergo gravitational collapse. Understanding how the SI operates in realistic protoplanetary disks (PPDs) is therefore crucial to assess the efficiency of planetesimal formation. Modern models of PPDs show that large-scale magnetic torques or winds can drive laminar gas accretion near the disk midplane. In a previous study, we identified a new linear dust-gas instability, the azimuthal drift SI (AdSI), applicable to such accreting disks and is powered by the relative azimuthal motion between dust and gas that results from the gas being torqued. In this work, we present the first nonlinear simulations of the AdSI. We show that it can destabilize an accreting, dusty disk even in the absence of a global radial pressure gradient, which is unlike the classic SI. We find the AdSI drives turbulence and the formation of vertically-extended dust filaments that undergo merging. In dust-rich disks, merged AdSI filaments reach maximum dust-to-gas ratios exceeding 100. Moreover, we find that even in dust-poor disks the AdSI can increase local dust densities by two orders of magnitude. We discuss the possible role of the AdSI in planetesimal formation, especially in regions of an accreting PPD with vanishing radial pressure gradients.Comment: Accepted by Ap

Geometrically Local Quantum and Classical Codes from Subdivision

A geometrically local quantum code is an error correcting code situated within $\mathbb{R}^D$, where the checks only act on qubits within a fixed spatial distance. The main question is: What is the optimal dimension and distance for a geometrically local code? This question was recently answered by Portnoy which constructed codes with optimal dimension and distance up to polylogs. This paper extends Portnoy's work by constructing a code which additionally has an optimal energy barrier up to polylogs. The key ingredient is a simpler code construction obtained by subdividing the balanced product codes. We also discuss applications to classical codes

The Trend and Intellectual Structure of Digital Archives Research

Archives are an extremely valuable part of cultural heritage since they represent the trace of the activities of a juridical person or organization in the course of their business. Through various information technology (IT), tremendous amount of digital archives (DA) are created. These archives are the basis for providing evidence and knowledge in everlasting memory of human society. The management of digital archives becomes a fast growing field throughout last decade and introduces abundant articles in academia. However, their trend and intellectual structure have remained obscure in the research community. To map the trend and intellectual structure of DA research, this study identifies the high-impact articles as well as the correlations among these scholar publications. In this study, text mining techniques, such as co-word and cluster analysis, have been deployed to investigate the intellectual pillars of the DA literature. This study exposes researchers to a new way of profiling knowledge networks and their relationships in the research area of DA, thereby helping academia and practitioners better understand up-to-date studies. The results of the mapping can help identify the research direction of DA research, provide a valuable tool for researchers to access DA literature, and act as an exemplary model for future research

An operator extension of weak monotonicity

Let $S(\rho)$ be the von Neumann entropy of a density matrix $\rho$. Weak monotonicity asserts that $S(\rho_{AB}) - S(\rho_A) + S(\rho_{BC}) - S(\rho_C)\geq 0$ for any tripartite density matrix $\rho_{ABC}$, a fact that is equivalent to the strong subadditivity of entropy. We prove an operator inequality, which, upon taking an expectation value with respect to the state $\rho_{ABC}$, reduces to the weak monotonicity inequality. Generalizations of this inequality to the one involving two independent density matrices, as well as their R\'enyi-generalizations, are also presented

Experimental demonstration of IDMA-OFDM for passive optical network

We present interleave division multiple access (IDMA) scheme combined with orthogonal frequency division multiplexing (OFDM) for passive optical network, which offers improved transmission performance and good chromatic dispersion tolerance. The interleavers are employed to separate different users and the generated chips are modulated on OFDM subcarriers. The feasibility of IDMA-OFDM-PON is experimentally verified with a bitrate of 3.3 Gb/s per user. Compared with OFDMA, IDMA-OFDM offers 8 and 6 dB gains in term of receiver sensitivity in the cases of 2 and 4 users, respectively

Excoecarianin, Isolated from Phyllanthus urinaria Linnea, Inhibits Herpes Simplex Virus Type 2 Infection through Inactivation of Viral Particles

Phyllanthus urinaria Linnea (Euphorbiaceae) is one of the traditional medicinal plants widely used by oriental people to treat various diseases. We have previously demonstrated that the acetone extract of P. urinaria inhibits herpes simplex virus type 2 (HSV-2) but not HSV-1 infection. In a continuing effort to clarify the antiviral mechanisms of P. urinaria, we isolated the pure compound excoecarianin from the whole plant of P. urinaria through acetone extraction, and investigated its anti-HSV-1 and HSV-2 activities. Our results indicated that excoecarianin protected Vero cells from HSV-2 but not HSV-1 infection, and its 50% inhibitory concentration (IC50) was 1.4 ± 0.1 μM. The antiviral effective concentration of excoecarianin did not affect the viability or the morphology of Vero cells. Although excoecarianin inhibited HSV-2 infection, the inhibitory effect, however, was most prominent when excoecarianin was concurrently added with the virus. Pretreatment of Vero cells with excoecarianin with removal of the drug prior to infection did not yield any antiviral effects, and the same observation was made for post viral entry treatment. Subsequent studies revealed that excoecarianin inactivated HSV-2 virus particles to prevent viral infection. A synergistic antiviral effect against HSV-2 was also observed when Vero cells were treated with a combination of acyclovir (ACV) and excoecarianin. These results suggested that excoecarianin merits to be further explored as an entry inhibitor against HSV-2 and could potentially be investigated for combinatorial drug treatment with nucleoside analogues such as ACV in therapeutic management of HSV-2 infection

Inferring Condition-Specific Targets of Human TF-TF Complexes Using ChIP-seq Data

Background: Transcription factors (TFs) often interact with one another to form TF complexes that bind DNA and regulate gene expression. Many databases are created to describe known TF complexes identified by either mammalian two-hybrid experiments or data mining. Lately, a wealth of ChIP-seq data on human TFs under different experiment conditions are available, making it possible to investigate condition-specific (cell type and/or physiologic state) TF complexes and their target genes. Results: Here, we developed a systematic pipeline to infer Condition-Specific Targets of human TF-TF complexes (called the CST pipeline) by integrating ChIP-seq data and TF motifs. In total, we predicted 2,392 TF complexes and 13,504 high-confidence or 127,994 low-confidence regulatory interactions amongst TF complexes and their target genes. We validated our predictions by (i) comparing predicted TF complexes to external TF complex databases, (ii) validating selected target genes of TF complexes using ChIP-qPCR and RT-PCR experiments, and (iii) analysing target genes of select TF complexes using gene ontology enrichment to demonstrate the accuracy of our work. Finally, the predicted results above were integrated and employed to construct a CST database. Conclusions: We built up a methodology to construct the CST database, which contributes to the analysis of transcriptional regulation and the identification of novel TF-TF complex formation in a certain condition. This database also allows users to visualize condition-specific TF regulatory networks through a user-friendly web interface