Improved test-retest reliability of R2∗\textit{R}_2^* and susceptibility quantification using multi-shot multi echo 3D EPI

This study aimed to evaluate the potential of 3D echo-planar imaging (EPI) for improving the reliability of $T_2^*$-weighted ($T_2^*w$) data and quantification of $\textit{R}_2^*$ decay rate and susceptibility ($\chi$) compared to conventional gradient echo (GRE)-based acquisition. Eight healthy subjects in a wide age range were recruited. Each subject received repeated scans for both GRE and EPI acquisitions with an isotropic 1 mm resolution at 3 T. Maps of $\textit{R}_2^*$ and $\chi$ were quantified and compared using their inter-scan difference to evaluate the test-retest reliability. Inter-protocol differences of $\textit{R}_2^*$ and $\chi$ between GRE and EPI were also measured voxel by voxel and in selected ROIs to test the consistency between the two acquisition methods. The quantifications of $\textit{R}_2^*$ and $\chi$ using EPI protocols showed increased test-retest reliability with higher EPI factors up to 5 as performed in the experiment and were consistent with those based on GRE. This result suggested multi-shot multi-echo 3D EPI can be a useful alternative acquisition method for $T_2^*w$ MRI and quantification of $\textit{R}_2^*$ and $\chi$ with reduced scan time, improved test-retest reliability and similar accuracy compared to commonly used 3D GRE.Comment: 18 pages, 8 figures and 1 tabl

Low expression of chloride channel accessory 1 predicts a poor prognosis in colorectal cancer

© 2014 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society. Funded by Friends of ANCHOR NHS Grampian Endowment Fund. Grant Number: 12/50Peer reviewedPublisher PD

Two-sided jumps risk model with proportional investment and random observation periods

In this paper, we consider a two-sided jumps risk model with proportional investments and random observation periods. The downward jumps represent the claim while the upward jumps represent the random returns. Suppose an insurance company invests all of their surplus in risk-free and risky investments in proportion. In real life, corporate boards regularly review their accounts rather than continuously monitoring them. Therefore, we assume that insurers regularly observe surplus levels to determine whether they will ruin and that the random observation periods are exponentially distributed. Our goal is to study the Gerber-Shiu function (i.e., the expected discounted penalty function) of the two-sided jumps risk model under random observation. First, we derive the integral differential equations (IDEs) satisfied by the Gerber-Shiu function. Due to the difficulty in obtaining explicit solutions for the IDEs, we utilize the sinc approximation method to obtain the approximate solution. Second, we analyze the error between the approximate and explicit solutions and find the upper bound of the error. Finally, we discuss examples of sensitivity analysis

Secured Data Transmission Over Insecure Networks-on-Chip by Modulating Inter-Packet Delays

As the network-on-chip (NoC) integrated into an SoC design can come from an untrusted third party, there is a growing risk that data integrity and security get compromised when supposedly sensitive data flows through such an untrusted NoC. We thus introduce a new method that can ensure secure and secret data transmission over such an untrusted NoC. Essentially, the proposed scheme relies on encoding binary data as delays between packets travelling across the source and destination pair. The maximum data transmission rate of this inter-packet-delay (IPD)-based communication channel can be determined from the analytical model developed in this article. To further improve the undetectability and robustness of the proposed data transmission scheme, a new block coding method and communication protocol are also proposed. Experimental results show that the proposed IPD-based method can achieve a packet error rate (PER) of as low as 0.3% and an effective throughput of $\boldsymbol {2.3\times 10^{5}}$ b/s, outperforming the methods of thermal covert channel, cache covert channel, and circuit-based encryption and, thus, is suitable for secure data transmission in unsecure systems

Numerical Method for a Risk Model with Two-Sided Jumps and Proportional Investment

In this paper, we consider a risk model with two-sided jumps and proportional investment. The upward jumps and downward jumps represent gains and claims, respectively. Suppose the company invests all of its surplus in a certain proportion in two types of investments, one is risk-free (such as bank accounts) and the other is risky (such as stocks). Our aim is to find the optimal admissible strategy (including the optimal dividend rate and the optimal ratio of investment in risky assets), to maximize the dividend value function, and discuss the effects of a number of parameters on dividend payments. Firstly, the HJB equation of the dividend value function is obtained by the stochastic analysis theory and the dynamic programming method, and the optimal admissible strategy is obtained. Since the integro-differential equation satisfied by the dividend value function is difficult to solve, we turn to the sinc numerical method to approximate solve it. Then, the error between the exact solution (ES) and the sinc approximate solution (SA) is analyzed. Finally, the relative error of a special numerical solution and an ES is given, and some examples of sensitivity analysis are discussed. This study provides a theoretical basis for insurance companies to prevent risks better

Exploring goodness of prosody by diverse matching templates

Abstract In automatic speech grading systems, rare research is followed through addressing the issue of GOR (Goodness Of pRosody). In this paper we propose a novel method by taking the advantage of our QBH (Query By Humming) techniques in 2008 MIREX evaluation task. A set of standard samples related to the top-cream students are initially picked up as templates, a cascade QBH structure is then taken from two metrics: the MOMEL stylization followed by DTW distance; the Fujisaki model followed by EMD distance. Sentence GOR is obtained by the fused confidence between target and each template, and forms a weighted sum as the goodness in the passage level. Experiment results indicate that performance increases with the count of template, and Fujisaki-EMD metric outperforms MOMEL-DTW one in terms of correlation. Their combination can be treated as template based GOR score, compensated with our previous feature based GOR score, the approach can achieve 0.432 in correlation and 17.90% in EER in our corpus

Comparative functional responses predict the invasiveness and ecological impacts of alien herbivorous snails.

Understanding determinants of the invasiveness and ecological impacts of alien species is amongst the most sought-after and urgent research questions in ecology. Several studies have shown the value of comparing the functional responses (FRs) of alien and native predators towards native prey, however, the technique is under-explored with herbivorous alien species and as a predictor of invasiveness as distinct from ecological impact. Here, in China, we conducted a mesocosm experiment to compare the FRs among three herbivorous snail species: the golden apple snail, Pomacea canaliculata, a highly invasive and high impact alien listed in "100 of the World's Worst Invasive Alien Species"; Planorbarius corneus, a non-invasive, low impact alien; and the Chinese native snail, Bellamya aeruginosa, when feeding on four locally occurring plant species. Further, by using a numerical response equation, we modelled the population dynamics of the snail consumers. For standard FR parameters, we found that the invasive and damaging alien snail had the highest "attack rates" a, shortest "handling times" h and also the highest estimated maximum feeding rates, 1/hT, whereas the native species had the lowest attack rates, longest handling times and lowest maximum feeding rates. The non-invasive, low impact alien species had consistently intermediate FR parameters. The invasive alien species had higher population growth potential than the native snail species, whilst that of the non-invasive alien species was intermediate. Thus, while the comparative FR approach has been proposed as a reliable method for predicting the ecological impacts of invasive predators, our results further suggest that comparative FRs could extend to predict the invasiveness and ecological impacts of alien herbivores and should be explored in other taxa and trophic groups to determine the general utility of the approach

Sex differences in cold hardiness and desiccation tolerance of invasive apple snails in South China

Sex differences in stress responses may be a key factor that determines population structure. Sex ratios of Pomacea canaliculata populations usually average 1:1 at birth, but are often female-biased for adults. Low temperatures and drought are the main abiotic stresses affecting reproductive dispersal and population development. Therefore, we investigated whether Pomacea sp. (mainly P. canaliculata but might include P. maculata) exhibited sex differences in cold hardiness and desiccation tolerance. Results show that more females survived than males during cold-drought stress and overwintering. Following cold-drought stress, 58% of females and 40% of males survived at 3°C drought conditions for 6 days. With the development of cold-drought hardiness, increased amounts of bound water, glycerol and lipids were found in Pomacea sp. along with decreased free water levels. These physiological parameters exhibited sex differences in the snails, except for lipids, and the changes all showed tendencies favoring the survival of females under cold-drought stress. These results suggest that female Pomacea sp. may be more viable than males under cold and dry conditions.Fil: Guo, Jing. South China Agricultural University. College of Natural Resources and Environment, Department of Ecology; República de ChinaFil: Xu, Wubing. South China Agricultural University. College of Natural Resources and Environment, Department of Ecology; República de ChinaFil: Martín, Pablo Rafael. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Laboratorio de Ecología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; ArgentinaFil: Zhang, Chunxia. South China Agricultural University. College of Natural Resources and Environment, Department of Ecology; República de ChinaFil: Zhang, Jiaen. South China Agricultural University. College of Natural Resources and Environment, Department of Ecology; República de China. Guangdong Engineering Research Center for Modern Eco-agriculture and Circular Agriculture; China. Ministry of Agriculture, Key Laboratory of Agro-Environment in the Tropics; Chin

Electrospun Fibrous Membrane with Confined Chain Configuration: Dynamic Relaxation and Glass Transition

Thermodynamic glass transition processes of electrospun membranes were first introduced to study their dynamic relaxation nature, which is not constantly in equilibrium. The relaxation modes of electrospun membranes are slow but measurable near and above the Tg, given the stretched chain over long distances. Based on differential scanning calorimetry (DSC) experiments and the general principle of mode-coupling theory (MCT), endothermic peak temperature and relaxation enthalpy were used to analyze the relaxation process by capturing these instantaneous “arrested” structures. The short- and long-wavelength relaxation modes could be identified with different annealing times and temperatures relative to DSC-measured Tg for electrospun membranes with different molecular weights. Results clearly showed the dynamic nature of a glass transition in polymeric materials. Tp and enthalpy loss initially increased and then directly decreased with the increase in annealing time. When Ta > Tg, regardless of the size of the molecular weight, the Tp and enthalpy loss of the PLGA fibers would directly decrease, and the curves would shift toward the melted one. Combination of electrospinningand normal DSC instrument can be used to investigating the dynamic relax process through an adequately designed kinetic scanning procedure. This result can be explained by the general principle of MCT-type dynamic theory