Event History Analysis of Dynamic Communication Networks

Statistical analysis on networks has received growing attention due to demand from various emerging applications. In dynamic networks, one of the key interests is to model the event history of time-stamped interactions amongst nodes. We propose to model dynamic directed communication networks via multivariate counting processes. A pseudo partial likelihood approach is exploited to capture the network dependence structure. Asymptotic results of the resulting estimation are established. Numerical results are performed to demonstrate effectiveness of our proposal

Application of indirect immunofluorescence on the diagnosis of pemphigus

Pemphigus is an autoimmune bullous disease, and although several diagnostic methods are now in use indirect immunofluorescence (IIF) is still considered an important tool for diagnosing pemphigus because of its convenience, repeatability, and reduced pain for patients. The goal of the present study was to evaluate the diagnostic value of IIF on normal human skin (NS), monkey esophagus (ME), and salt-split skin (SS) for better diagnosis of pemphigus. Clinical data of 70 patients with pemphigus and 56 control were collected. IIF on NS, ME, and SS were assessed separately by observing fluorescein deposition and comparing its differentiation to different kinds of pemphigus and its sensitivities and specificities to different substrates. Intercellular deposition of IgG was visible when IIF on NS, ME, and SS were positive in patients with pemphigus. Their corresponding sensitivities and specificities were 30.0%, 84.3%, and 70.0% and 96.4%, 96.4%, and 94.6%, respectively. The differences in sensitivity were statistically significant between NS and ME and between NS and SS (P&lt;0.001) and the specificities among the three substrates were not statistically significantly different (P&gt;0.05). As for different types of pemphigus, the sensitivities between NS and ME and between NS and SS were statistically significantly different in both Dsg1- and Dsg3-positive and only Dsg1-positive patients with pemphigus (P&lt;0.01); the sensitivities between NS and ME were statistically significantly different only in Dsg3-positive patients with pemphigus (P&lt;0.001); there were no statistically significant differences between ME and SS. We therefore propose that ME is a good substrate for pemphigus diagnosis with higher sensitivity and superior to NS, particularly for patients with anti-Dsg3 antibodies. SS is a good alternative substrate to ME with almost identical higher sensitivities and specificities for diagnosis of pemphigus.</p

Exploring Regulation Genes Involved in the Expression of L-Amino Acid Oxidase in Pseudoalteromonas sp. Rf-1

Bacterial L-amino acid oxidase (LAAO) is believed to play important biological and ecological roles in marine niches, thus attracting increasing attention to understand the regulation mechanisms underlying its production. In this study, we investigated genes involved in LAAO production in marine bacterium Pseudoalteromonas sp. Rf-1 using transposon mutagenesis. Of more than 4,000 mutants screened, 15 mutants showed significant changes in LAAO activity. Desired transposon insertion was confirmed in 12 mutants, in which disrupted genes and corresponding functionswere identified. Analysis of LAAO activity and lao gene expression revealed that GntR family transcriptional regulator, methylase, non-ribosomal peptide synthetase, TonB-dependent heme-receptor family, Na⁺/H⁺ antiporter and related arsenite permease, N-acetyltransferase GCN5, Ketol-acid reductoisomerase and SAM-dependent methytransferase, and their coding genes may be involved in either upregulation or downregulation pathway at transcriptional, posttranscriptional, translational and/or posttranslational level. The nhaD and sdmT genes were separately complemented into the corresponding mutants with abolished LAAO-activity. The complementation of either gene can restore LAAO activity and lao gene expression, demonstrating their regulatory role in LAAO biosynthesis. This study provides, for the first time, insights into the molecular mechanisms regulating LAAO production in Pseudoalteromonas sp. Rf-1, which is important to better understand biological and ecological roles of LAAO

Long-term effects of fire and harvest on carbon stocks of boreal forests in northeastern China

International audienceAbstractKey messageFire, harvest, and their spatial interactions are likely to affect boreal forest carbon stocks. Repeated disturbances associated with short fire return intervals and harvest rotations resulted in landscapes with a higher proportion of young stands that store less carbon than mature stands.ContextBoreal forests represent about one third of forest area and one third of forest carbon stocks on the Earth. Carbon stocks of boreal forests are sensitive to climate change, natural disturbances, and human activities.AimsThe objectives of this study were to evaluate the effects of fire, harvest, and their spatial interactions on boreal forest carbon stocks of northeastern China.MethodsWe used a coupled forest landscape model (LANDIS PRO) and a forest ecosystem model (LINKAGES) framework to simulate the landscape-level effects of fire, harvest, and their spatial interactions over 150 years.ResultsOur simulation suggested that aboveground carbon and soil organic carbon are significantly reduced by fire and harvest over the whole simulation period. The long-term effects of fire and harvest on carbon stocks were greater than the short-term effects. The combined effects of fire and harvest on carbon stocks are less than the sum of the separate effects of fire and harvest. The response of carbon stocks was impacted by the spatial variability of fire and harvest regimes.ConclusionThese results emphasize that the spatial interactions of fire and harvest play an important role in regulating boreal forest carbon stocks

Modified Projective Synchronization between Different Fractional-Order Systems Based on Open-Plus-Closed-Loop Control and Its Application in Image Encryption

A new general and systematic coupling scheme is developed to achieve the modified projective synchronization (MPS) of different fractional-order systems under parameter mismatch via the Open-Plus-Closed-Loop (OPCL) control. Based on the stability theorem of linear fractional-order systems, some sufficient conditions for MPS are proposed. Two groups of numerical simulations on the incommensurate fraction-order system and commensurate fraction-order system are presented to justify the theoretical analysis. Due to the unpredictability of the scale factors and the use of fractional-order systems, the chaotic data from the MPS is selected to encrypt a plain image to obtain higher security. Simulation results show that our method is efficient with a large key space, high sensitivity to encryption keys, resistance to attack of differential attacks, and statistical analysis

Experimental Quantum Communication Overcomes the Rate-loss Limit without Global Phase Tracking

Secure key rate (SKR) of point-point quantum key distribution (QKD) is fundamentally bounded by the rate-loss limit. Recent breakthrough of twin-field (TF) QKD can overcome this limit and enables long distance quantum communication, but its implementation necessitates complex global phase tracking and requires strong phase references which not only add to noise but also reduce the duty cycle for quantum transmission. Here, we resolve these shortcomings, and importantly achieve even higher SKRs than TF-QKD, via implementing an innovative but simpler measurement-device-independent QKD which realizes repeater-like communication through asynchronous coincidence pairing. Over 413 and 508 km optical fibers, we achieve finite-size SKRs of 590.61 and 42.64 bit/s, which are respectively 1.80 and 4.08 times of their corresponding absolute rate limits. Significantly, the SKR at 306 km exceeds 5 kbit/s and meets the bitrate requirement for live one-time-pad encryption of voice communication. Our work will bring forward economical and efficient intercity quantum-secure networks.Comment: 29 pages, 10 figures, 3 table