Threshold for the Outbreak of Cascading Failures in Degree-degree Uncorrelated Networks

In complex networks, the failure of one or very few nodes may cause cascading failures. When this dynamical process stops in steady state, the size of the giant component formed by remaining un-failed nodes can be used to measure the severity of cascading failures, which is critically important for estimating the robustness of networks. In this paper, we provide a cascade of overload failure model with local load sharing mechanism, and then explore the threshold of node capacity when the large-scale cascading failures happen and un-failed nodes in steady state cannot connect to each other to form a large connected sub-network. We get the theoretical derivation of this threshold in degree-degree uncorrelated networks, and validate the effectiveness of this method in simulation. This threshold provide us a guidance to improve the network robustness under the premise of limited capacity resource when creating a network and assigning load. Therefore, this threshold is useful and important to analyze the robustness of networks.Comment: 11 pages, 4 figure

Interval Forecasting of Carbon Futures Prices Using a Novel Hybrid Approach with Exogenous Variables

This paper examines the interval forecasting of carbon futures prices in one of the most important carbon futures market. Specifically, the purpose of this study is to present a novel hybrid approach, which is composed of multioutput support vector regression (MSVR) and particle swarm optimization (PSO), in the task of forecasting the highest and lowest prices of carbon futures on the next trading day. Furthermore, we set out to investigate if considering some potential predictors, which have strong influence on carbon futures prices, in modeling process is useful for achieving better prediction performance. Aiming at testing its effectiveness, we benchmark the forecasting performance of our approach against four competitors. The daily interval prices of carbon futures contracts traded in the Intercontinental Futures Exchange from August 12, 2010, to November 13, 2014, are used as the experiment dataset. The statistical significance of the interval forecasts is examined. The proposed hybrid approach is found to demonstrate the higher forecasting performance relative to all other competitors. Our application offers practitioners a promising set of results with interval forecasting in carbon futures market

SIRT6 promotes metastasis and relapse in HER2-positive breast cancer

The histone deacetylase sirtuin 6 (SIRT6) has been endowed with anti-cancer capabilities in many tumor types. Here, we investigate the impact of SIRT6-overexpression (SIRT6-OE) in Delta16HER2 mice, which are a bona fide model of HER2-positive breast cancer. After an initial delay in the tumor onset, SIRT6-OE induces a more aggressive phenotype of Delta16HER2 tumors promoting the formation of higher number of tumor foci and metastases than controls. This phenotype of SIRT6-OE tumors is associated with cancer stem cell (CSC)-like features and tumor dormancy, and low senescence and oxidative DNA damage. Accordingly, a sub-set of HER2-positive breast cancer patients with concurrent SIRT6-OE has a significant poorer relapse-free survival (RFS) probability than patients with low expression of SIRT6. ChIP-seq, RNA-seq and RT-PCR experiments indicate that SIRT6-OE represses the expression of the T-box transcription factor 3 (Tbx3) by deacetylation of H3K9ac. Accordingly, loss-of-function mutations of TBX3 or low TBX3 expression levels are predictive of poor prognosis in HER2-positive breast cancer patients. Our work indicates that high levels of SIRT6 are indicative of poor prognosis and high risk of metastasis in HER2-positive breast cancer and suggests further investigation of TBX3 as a downstream target of SIRT6 and co-marker of poor-prognosis. Our results point to a breast cancer subtype-specific effect of SIRT6 and warrant future studies dissecting the mechanisms of SIRT6 regulation in different breast cancer subtypes

Manipulating the 3D organization of the largest synthetic yeast chromosome

Whether synthetic genomes can power life has attracted broad interest in the synthetic biology field. Here, we report de novo synthesis of the largest eukaryotic chromosome thus far, synIV, a 1,454,621-bp yeast chromosome resulting from extensive genome streamlining and modification. We developed megachunk assembly combined with a hierarchical integration strategy, which significantly increased the accuracy and flexibility of synthetic chromosome construction. Besides the drastic sequence changes, we further manipulated the 3D structure of synIV to explore spatial gene regulation. Surprisingly, we found few gene expression changes, suggesting that positioning inside the yeast nucleoplasm plays a minor role in gene regulation. Lastly, we tethered synIV to the inner nuclear membrane via its hundreds of loxPsym sites and observed transcriptional repression of the entire chromosome, demonstrating chromosome-wide transcription manipulation without changing the DNA sequences. Our manipulation of the spatial structure of synIV sheds light on higher-order architectural design of the synthetic genomes. </p

YeastFab:the design and construction of standard biological parts for metabolic engineering in Saccharomyces cerevisiae

It is a routine task in metabolic engineering to introduce multicomponent pathways into a heterologous host for production of metabolites. However, this process sometimes may take weeks to months due to the lack of standardized genetic tools. Here, we present a method for the design and construction of biological parts based on the native genes and regulatory elements in Saccharomyces cerevisiae. We have developed highly efficient protocols (termed YeastFab Assembly) to synthesize these genetic elements as standardized biological parts, which can be used to assemble transcriptional units in a single-tube reaction. In addition, standardized characterization assays are developed using reporter constructs to calibrate the function of promoters. Furthermore, the assembled transcription units can be either assayed individually or applied to construct multi-gene metabolic pathways, which targets a genomic locus or a receiving plasmid effectively, through a simple in vitro reaction. Finally, using β-carotene biosynthesis pathway as an example, we demonstrate that our method allows us not only to construct and test a metabolic pathway in several days, but also to optimize the production through combinatorial assembly of a pathway using hundreds of regulatory biological parts

Wireless Access to a Content Routing System

We present in this paper our experience in providing a wireless access interface to a distributed content search and delivery system. Important Wireless Application Protocol(WAP) gateway functions, in particular the Push function, are integrated into the access points of the system. Wireless devices can use this interface to search for distributed information and get notified of relevant new content. A prototype implementation of the integration has been completed which works successfully with WAP 1.2 compliant clients

Optimal Buffering Algorithms For Client-Server Vbr Video Retrievals

OF THE DISSERTATION Optimal buffering algorithms for client-server VBR video retrievals by Junbiao Zhang Dissertation Director: Prof. Joseph Y. Hui, Prof. Naftaly Minsky Variable bit rate(VBR) videos refer to videos with varying frame sizes. When transmitted through networks in a client-server environment, their corresponding traffic is inherently bursty because of the embedded timing constraints in digital videos. In reservation based networks like ATM network, such traffic may result in considerable network under-utilization if the network has to accommodate the peak bit rate. Traffic smoothing is thus necessary to reduce the burstiness in the VBR video traffic and it can be very effective in the case of stored video. By introducing a playback delay and buffering video data on the client side, a smoother traffic can be transmitted by the server. In order for the client to restore the original timing information in the video, it is important to avoid buffer overflow or underflow durin..

Evaluation of GHG Mitigation Measures in Rice Cropping and Effects of Farmer’s Characteristics: Evidence from Hubei, China

Greenhouse Gas emissions from agricultural activities, such as rice cropping, have been proven to be an important cause of climate change, with constant barriers and constraints in the implementation and promotion of mitigation measures among farmers in China. However, there has been a lack of research focusing on specific mitigation measures and their characteristics. In this paper, we applied the expert assessment and best-worst scaling method to evaluate mitigation measures in rice cropping from the perspectives of effectiveness and applicability. The results showed that no mitigation measure in rice cropping was best from both an effectiveness and applicability viewpoint. However, the study found that “reducing the use of chemical fertilizers” was the most effective one, while “applying soil testing and formulated fertilization” was the most applicable one. Additionally, the older farmers spending more time on non-agricultural jobs and farming more plots of land were more likely to believe that mitigation measures related to the management of input elements would be more applicable compared to soil and water management or some types of new science and technology. Finally, we suggested that the agricultural extension agencies should popularize input elements management such as improvement of fertilizer or seeds among older farmers, and meanwhile promote soil cultivation management and new technologies for agriculture in areas where the land is more concentrated such as plains