Waiting time distribution of solar energetic particle events modeled with a non-stationary Poisson process

We present a study of the waiting time distributions (WTDs) of solar energetic particle (SEP) events observed with the spacecraft $WIND$ and $GOES$. Both the WTDs of solar electron events (SEEs) and solar proton events (SPEs) display a power-law tail $\sim \Delta t^{-\gamma}$. The SEEs display a broken power-law WTD. The power-law index is $\gamma_{1} =$ 0.99 for the short waiting times ($$100 hours). The break of the WTD of SEEs is probably due to the modulation of the corotating interaction regions (CIRs). The power-law index $\gamma \sim$ 1.82 is derived for the WTD of SPEs that is consistent with the WTD of type II radio bursts, indicating a close relationship between the shock wave and the production of energetic protons. The WTDs of SEP events can be modeled with a non-stationary Poisson process which was proposed to understand the waiting time statistics of solar flares (Wheatland 2000; Aschwanden $\&$ McTiernan 2010). We generalize the method and find that, if the SEP event rate $\lambda = 1/\Delta t$ varies as the time distribution of event rate $f(\lambda) = A \lambda^{-\alpha}exp(-\beta \lambda)$, the time-dependent Poisson distribution can produce a power-law tail WTD $\sim \Delta t^{\alpha - 3}$, where $0 \leq \alpha < 2$.Comment: 10 pages, 4 figures, accepted for publication in ApJ Letter

Interconnectedness and Systemic Risk: A Comparative Study Based on Systemically Important Regions

We apply a novel technique to identify systemically important regions (SIRs) in a global network that shows a reduced degree of concentration and the development of a multi-centered structure. We observe that when a region is more connected to other regions, it is exposed to a higher level of systemic risk. This condition holds even more strongly for non-systemically important regions. However, for SIRs, interconnectedness is not significantly associated with systemic risk. Our empirical evidence suggests that an increase in interconnectedness at the regional level, together with a decrease in interconnectedness for a single pivotal center, may reduce the aggregate systemic risk at the global level

Natural Science

Preparation of lignin derivatives and their application as protease adsorbent

Restoration of images based on subspace optimization accelerating augmented Lagrangian approach

AbstractWe propose a new fast algorithm for solving a TV-based image restoration problem. Our approach is based on merging subspace optimization methods into an augmented Lagrangian method. The proposed algorithm can be seen as a variant of the ALM (Augmented Lagrangian Method), and the convergence properties are analyzed from a DRS (Douglas–Rachford splitting) viewpoint. Experiments on a set of image restoration benchmark problems show that the proposed algorithm is a strong contender for the current state of the art methods

Adaptive web service selection based on data type matching for dynamic web service composition

Although there are many web services provided for access in World Wide Web (WWW), some services are not available at all times.It is very important to ensure all services are available when a service composition takes place.A web service that meets the requirements of the workflow but does not match the data type will still cause a failure in composition.To address this concern, we propose an adaptive web service selection method which is able to replace a current web service which has been used for composition but fails during execution time.The proposed algorithm will select the most appropriate web service based on web service discovery engine recommendation and match the requirement based on WSDL description. Upon matching the requirements of the workflow, the selected web service will be matched according to the input and output data type. The goal of this paper is to ensure every web service that meets the requirements of the workflow does not get rejected when the data type does not fulfill the matching criteria

Webs: A web accessibility barrier severity metric

A novel metric for quantitatively measuring the severity of websites barriers that limit the accessibility for disabled people is proposed. The metric is based on the Web Content Accessibility Guidelines (WCAG 2.0), which is the most adopted voluntary web accessibility standard internationally that can be tested automatically. The proposed metric is intended to rank the accessibility barriers based on their severity rather than the total conformance to priority levels.Our metric meets the requirements as a measurement for scientific research. An experiment is conducted to assess the results of our metric and to reveal the commonplace violations that persist in websites and affect disabled people interacting with the web

Factors Affecting Occupational Exposure to Needlestick and Sharps Injuries among Dentists in Taiwan: A Nationwide Survey

BACKGROUND: Although the risks of needlestick and sharps injuries (NSIs) for dentists are well recognized, most papers published only described the frequency of occupational exposure to NSIs. Less has been reported assessing factors contributing to exposure to NSIs. The purpose of this study was to update the epidemiology of NSIs among dentists in Taiwan and identify factors affecting NSIs in order to find preventive strategies. METHODOLOGY/PRINCIPAL FINDINGS: A nationwide survey was conducted in dentists at 60 hospitals and 340 clinics in Taiwan. The survey included questions about factors supposedly affecting exposure to NSIs, such as dentist and facility characteristics, knowledge and attitudes about infectious diseases, and practices related to infection control. Univariate and multivariate logistic regression analyses were conducted to determine the association between risk factors and exposure to NSIs. In total, 434 (74.8%) of 580 dentists returned the survey questionnaires, and 100 (23.0%) reported that they had experienced more than one NSI per week. Our data showed that the risk of occupational NSIs is similarly heightened by an older age (odds ratio [OR], 3.18; 95% confidence interval [CI], 1.62-6.25), more years in practice (OR, 2.57; 95% CI, 1.41-4.69), working in clinics (OR, 1.73; 95% CI, 1.08-2.77), exhibiting less compliance with infection-control procedures (OR, 1.82; 95% CI, 1.04-3.18), having insufficient knowledge of blood-borne pathogens (OR, 1.67; 95% CI, 1.04-2.67), and being more worried about being infected by blood-borne pathogens (OR, 1.82; 95% CI, 1.05-3.13). CONCLUSIONS/SIGNIFICANCE: High rates of NSIs and low compliance with infection-control procedures highly contribute to the chance of acquiring a blood-borne pathogen infection and threaten occupational safety. This study reveals the possible affecting factors and helps in designing prevention strategies for occupational exposure to NSIs

Bank Credit Strategy Model Based on AHP-Fuzzy Comprehensive Evaluation

Credit risk control and credit strategy formulation of medium and micro enterprises have always been important strategic issues faced by commercial banks. Banks usually make corporate loan policies based on the credit degree, the information of trading bills and the relationship of supply-demand chain of the enterprise. In this paper, we established the AHP-Fuzzy comprehensive evaluation model for quantifying enterprise credit risk. Based on the relevant data of 123 enterprises with credit records, the credit strategy is formulated according to the three indicators of enterprise strength, enterprise reputation and stability of supply-demand relationship. This paper also combines the credit reputation, credit risk and supply and demand stability rating in order to establish the bank credit strategic planning model to decide whether to lend or not and the lending order. The conclusion shows that, under the condition of constant total loan amount, the enterprises with the highest credit rating should be given priority. Then, combined with the change of customer turnover rate with interest rate, we take the bank's maximize expected income as objective to calculate the optimal loan interest rate of different customer groups

Minute-Level Speed Identification and Assessment of Bacteria/Cells Using Electrokinetic Assistance

Conventional techniques for detection and analysis of cells/bacteria use Western blot and ELISA kits that are high cost and long time consuming. An ideal advanced biosensor (molecular or whole cells detections) unit must have several important features: rapid detection time (&lt;15 minutes), high sensitivity (102 cells/ml for whole cell detection or sub-nM concentration for molecular detection), high specificity, small, and inexpensive instrumentation/configuration. Two novel platforms will be introduced here, including an optofluidic system for the rapid on-chip detection of bacterial infection and a cell-based biochip for the label-free assessment of drug susceptibility on cancer cells. Rapid identification of rare pathogen from a very dense human blood sample is realized through combining the hybrid electrokinetic concentration with on-chip surface-enhanced Raman spectroscopy (SERS) identification of bacteria based on their detected SERS spectra. Compared to the current method in the hospital, this simple and rapid platform accelerated the detection time from 2 days to a few minutes. The cell-based biochip uses a novel, rapid, and label-free approach- AC electric field induced electro-rotation (eROT) to evaluate the drug susceptibility of cancer cells. The isolated lung cancer cells were successfully analyzed using eROT approach for the rapid and label-free assessment of the drug susceptibility of cancer cells. eROT spectra for different drug-treated cancer cells was successfully determined to the drug resistance and susceptibilities through their frequency-dependent rotation speeds. The relationship and trend between eROT method and conventional method are very agreement