The Best Answers? Think Twice: Online Detection of Commercial Campaigns in the CQA Forums

In an emerging trend, more and more Internet users search for information from Community Question and Answer (CQA) websites, as interactive communication in such websites provides users with a rare feeling of trust. More often than not, end users look for instant help when they browse the CQA websites for the best answers. Hence, it is imperative that they should be warned of any potential commercial campaigns hidden behind the answers. However, existing research focuses more on the quality of answers and does not meet the above need. In this paper, we develop a system that automatically analyzes the hidden patterns of commercial spam and raises alarms instantaneously to end users whenever a potential commercial campaign is detected. Our detection method integrates semantic analysis and posters' track records and utilizes the special features of CQA websites largely different from those in other types of forums such as microblogs or news reports. Our system is adaptive and accommodates new evidence uncovered by the detection algorithms over time. Validated with real-world trace data from a popular Chinese CQA website over a period of three months, our system shows great potential towards adaptive online detection of CQA spams.Comment: 9 pages, 10 figure

Binding kinetics of membrane-anchored receptors and ligands: molecular dynamics simulations and theory

The adhesion of biological membranes is mediated by the binding of membrane-anchored receptor and ligand proteins. Central questions are how the binding kinetics of these proteins is affected by the membranes and by the membrane anchoring of the proteins. In this article, we (i) present detailed data for the binding of membrane-anchored proteins from coarse-grained molecular dynamics simulations, and (ii) provide a theory that describes how the binding kinetics depends on the average separation and thermal roughness of the adhering membranes, and on the anchoring, lengths, and length variations of the proteins. An important element of our theory is the tilt of bound receptor-ligand complexes and transition-state complexes relative to the membrane normals. This tilt results from an interplay of the anchoring energy and rotational entropy of the complexes and facilitates the formation of receptor-ligand bonds at membrane separations smaller than the preferred separation for binding. In our simulations, we have considered both lipid-anchored and transmembrane receptor and ligand proteins. We find that the binding equilibrium constant and binding on-rate constant of lipid-anchored proteins are considerably smaller than the binding constant and on-rate constant of rigid transmembrane proteins with identical binding domains.Comment: 13 pages, 6 figures; to appear in J. Chem. Phy

TLR ligand-induced podosome disassembly in dendritic cells is ADAM17 dependent

Toll-like receptor (TLR) signaling induces a rapid reorganization of the actin cytoskeleton in cultured mouse dendritic cells (DC), leading to enhanced antigen endocytosis and a concomitant loss of filamentous actin–rich podosomes. We show that as podosomes are lost, TLR signaling induces prominent focal contacts and a transient reduction in DC migratory capacity in vitro. We further show that podosomes in mouse DC are foci of pronounced gelatinase activity, dependent on the enzyme membrane type I matrix metalloprotease (MT1-MMP), and that DC transiently lose the ability to degrade the extracellular matrix after TLR signaling. Surprisingly, MMP inhibitors block TLR signaling–induced podosome disassembly, although stimulated endocytosis is unaffected, which demonstrates that the two phenomena are not obligatorily coupled. Podosome disassembly caused by TLR signaling occurs normally in DC lacking MT1-MMP, and instead requires the tumor necrosis factor α–converting enzyme ADAM17 (a disintegrin and metalloprotease 17), which demonstrates a novel role for this “sheddase” in regulating an actin-based structure

Determining Training Needs for Cloud Infrastructure Investigations using I-STRIDE

As more businesses and users adopt cloud computing services, security vulnerabilities will be increasingly found and exploited. There are many technological and political challenges where investigation of potentially criminal incidents in the cloud are concerned. Security experts, however, must still be able to acquire and analyze data in a methodical, rigorous and forensically sound manner. This work applies the STRIDE asset-based risk assessment method to cloud computing infrastructure for the purpose of identifying and assessing an organization's ability to respond to and investigate breaches in cloud computing environments. An extension to the STRIDE risk assessment model is proposed to help organizations quickly respond to incidents while ensuring acquisition and integrity of the largest amount of digital evidence possible. Further, the proposed model allows organizations to assess the needs and capacity of their incident responders before an incident occurs.Comment: 13 pages, 3 figures, 3 tables, 5th International Conference on Digital Forensics and Cyber Crime; Digital Forensics and Cyber Crime, pp. 223-236, 201

Thermodynamic properties of binary HCP solution phases from special quasirandom structures

Three different special quasirandom structures (SQS) of the substitutional hcp $A_{1-x}B_x$ binary random solutions ($x=0.25$, 0.5, and 0.75) are presented. These structures are able to mimic the most important pair and multi-site correlation functions corresponding to perfectly random hcp solutions at those compositions. Due to the relatively small size of the generated structures, they can be used to calculate the properties of random hcp alloys via first-principles methods. The structures are relaxed in order to find their lowest energy configurations at each composition. In some cases, it was found that full relaxation resulted in complete loss of their parental symmetry as hcp so geometry optimizations in which no local relaxations are allowed were also performed. In general, the first-principles results for the seven binary systems (Cd-Mg, Mg-Zr, Al-Mg, Mo-Ru, Hf-Ti, Hf-Zr, and Ti-Zr) show good agreement with both formation enthalpy and lattice parameters measurements from experiments. It is concluded that the SQS's presented in this work can be widely used to study the behavior of random hcp solutions.Comment: 15 pages, 8 figure

A Mutation in the DNA Polymerase Accessory Factor of Herpes Simplex Virus 1 Restores Viral DNA Replication in the Presence of Raltegravir

This is the published version. Copyright 2014 American Society for MicrobiologyPrevious reports showed that raltegravir, a recently approved antiviral compound that targets HIV integrase, can inhibit the nuclease function of human cytomegalovirus (HCMV terminase) in vitro. In this study, subtoxic levels of raltegravir were shown to inhibit the replication of four different herpesviruses, herpes simplex virus 1 (HSV-1), HSV-2, HCMV, and mouse cytomegalovirus, by 30- to 700-fold, depending on the dose and the virus tested. Southern blotting and quantitative PCR revealed that raltegravir inhibits DNA replication of HSV-1 rather than cleavage of viral DNA. A raltegravir-resistant HSV-1 mutant was generated by repeated passage in the presence of 200 μM raltegravir. The genomic sequence of the resistant virus, designated clone 7, contained mutations in 16 open reading frames. Of these, the mutations F198S in unique long region 15 (UL15; encoding the large terminase subunit), A374V in UL32 (required for DNA cleavage and packaging), V296I in UL42 (encoding the DNA polymerase accessory factor), and A224S in UL54 (encoding ICP27, an important transcriptional regulator) were introduced independently into the wild-type HSV-1(F) genome, and the recombinant viruses were tested for raltegravir resistance. Viruses bearing both the UL15 and UL32 mutations inserted within the genome of the UL42 mutant were also tested. While the UL15, UL32, and UL54 mutant viruses were fully susceptible to raltegravir, any virus bearing the UL42 mutation was as resistant to raltegravir as clone 7. Overall, these results suggest that raltegravir may be a valuable therapeutic agent against herpesviruses and the antiviral activity targets the DNA polymerase accessory factor rather than the nuclease activity of the terminase

Adaptive expression responses in the Pol-γ null strain of S. pombe depleted of mitochondrial genome

<p>Abstract</p> <p>Background</p> <p>DNA polymerase γ(Pol-γ) has been shown to be essential for maintenance of the mitochondrial genome (mtDNA) in the petite-positive budding yeast <it>Saccharomyces cerevisiae</it>. Budding yeast cells lacking mitochondria exhibit a slow-growing or petite-colony phenotype. Petite strains fail to grow on non-fermentable carbon sources. However, it is not clear whether the Pol-γ is required for mtDNA maintenance in the petite-negative fission yeast <it>Schizosaccharomyces pombe</it>.</p> <p>Results</p> <p>We show that disruption of the nuclear gene <it>pog1</it>⁺that encodes Pol-γ is sufficient to deplete mtDNA in <it>S. pombe</it>. Cells bearing <it>pog1Δ </it>allele require substantial growth periods to form petite colonies. Mitotracker assays indicate that <it>pog1Δ </it>cells are defective in mitochondrial function and EM analyses suggest that <it>pog1Δ </it>cells lack normal mitochondrial structures. Depletion of mtDNA in <it>pog1Δ </it>cells is evident from quantitative real-time PCR assays. Genome-wide expression profiles of <it>pog1Δ </it>and other mtDNA-less cells reveal that many genes involved in response to stimulus, energy derivation by oxidation of organic compounds, cellular carbohydrate metabolism, and energy reserve metabolism are induced. Conversely, many genes encoding proteins involved in amino acid metabolism and oxidative phosphorylation are repressed.</p> <p>Conclusion</p> <p>By showing that Pol-γ is essential for mtDNA maintenance and disruption of <it>pog1</it>⁺alters the genome-wide expression profiles, we demonstrated that cells lacking mtDNA exhibit adaptive nuclear gene expression responses in the petite-negative <it>S. pombe</it>.</p

The Possible Tragedy of Quantitative Easing: An IS-LM Approach

The object of this paper is to demonstrate the possible risks of quantitative easing in the long run. The analysis is conducted in the conventional framework of IS-LM curves in a sequential model, which assumes that the independence of supply and demand curves does not necessarily hold. It is established that this lack of independence coupled with a very flat (or kinked) IS curve may lead to falls in income in second period as a consequence of quantitative easing. Such easing may alter the behavior of investors who get encouraged to undertake very risky and leveraged investments. Thus, short term gains may be outweighed by long term losses from quantitative easing. In some cases such easing may create bubbles in the economy, for example, in the housing and stock markets which collapse at some point in time