583 research outputs found

    Automated Testing of WS-BPEL Service Compositions: A Scenario-Oriented Approach

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    Nowadays, Service Oriented Architecture (SOA) has become one mainstream paradigm for developing distributed applications. As the basic unit in SOA, Web services can be composed to construct complex applications. The quality of Web services and their compositions is critical to the success of SOA applications. Testing, as a major quality assurance technique, is confronted with new challenges in the context of service compositions. In this paper, we propose a scenario-oriented testing approach that can automatically generate test cases for service compositions. Our approach is particularly focused on the service compositions specified by Business Process Execution Language for Web Services (WS-BPEL), a widely recognized executable service composition language. In the approach, a WS-BPEL service composition is first abstracted into a graph model; test scenarios are then derived from the model; finally, test cases are generated according to different scenarios. We also developed a prototype tool implementing the proposed approach, and an empirical study was conducted to demonstrate the applicability and effectiveness of our approach. The experimental results show that the automatic scenario-oriented testing approach is effective in detecting many types of faults seeded in the service compositions

    Effects of Lattice and Molecular Phonons on Photoinduced Neutral-to-Ionic Transition Dynamics in Tetrathiafulvalene-pp-Chloranil

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    For electronic states and photoinduced charge dynamics near the neutral-ionic transition in the mixed-stack charge-transfer complex tetrathiafulvalene-pp-chloranil (TTF-CA), we review the effects of Peierls coupling to lattice phonons modulating transfer integrals and Holstein couplings to molecular vibrations modulating site energies. The former stabilizes the ionic phase and reduces discontinuities in the phase transition, while the latter stabilizes the neutral phase and enhances the discontinuities. To reproduce the experimentally observed ionicity, optical conductivity and photoinduced charge dynamics, both couplings are quantitatively important. In particular, strong Holstein couplings to form the highly-stabilized neutral phase are necessary for the ionic phase to be a Mott insulator with large ionicity. A comparison with the observed photoinduced charge dynamics indicates the presence of strings of lattice dimerization in the neutral phase above the transition temperature.Comment: 9 pages, 7 figures, accepted for publication in J. Phys. Soc. Jp

    Phase Transition in a One-Dimensional Extended Peierls-Hubbard Model with a Pulse of Oscillating Electric Field: I. Threshold Behavior in Ionic-to-Neutral Transition

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    Photoinduced dynamics of charge density and lattice displacements is calculated by solving the time-dependent Schr\"odinger equation for a one-dimensional extended Peierls-Hubbard model with alternating potentials for the mixed-stack organic charge-transfer complex, TTF-CA. A pulse of oscillating electric field is incorporated into the Peierls phase of the transfer integral. The frequency, the amplitude, and the duration of the pulse are varied to study the nonlinear and cooperative character of the photoinduced transition. When the dimerized ionic phase is photoexcited, the threshold behavior is clearly observed by plotting the final ionicity as a function of the increment of the total energy. Above the threshold photoexcitation, the electronic state reaches the neutral one with equidistant molecules after the electric field is turned off. The transition is initiated by nucleation of a metastable neutral domain, for which an electric field with frequency below the linear absorption peak is more effective than that at the peak. When the pulse is strong and short, the charge transfer takes place on the same time scale with the disappearance of dimerization. As the pulse becomes weak and long, the dimerization-induced polarization is disordered to restore the inversion symmetry on average before the charge transfer takes place to bring the system neutral. Thus, a paraelectric ionic phase is transiently realized by a weak electric field. It is shown that infrared light also induces the ionic-to-neutral transition, which is characterized by the threshold behavior.Comment: 24 pages, 11 figure

    Multi-component Transparent Conducting Oxides: Progress in Materials Modelling

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    Transparent conducting oxides (TCOs) play an essential role in modern optoelectronic devices through their combination of electrical conductivity and optical transparency. We review recent progress in our understanding of multi-component TCOs formed from solid-solutions of ZnO, In2O3, Ga2O3 and Al2O3, with a particular emphasis on the contributions of materials modelling, primarily based on Density Functional Theory. In particular, we highlight three major results from our work: (i) the fundamental principles governing the crystal structures of multi-component oxide structures including (In2O3)(ZnO)n, named IZO, and (In2O3)m(Ga2O3)l(ZnO)n, named IGZO; (ii) the relationship between elemental composition and optical and electrical behaviour, including valence band alignments; (iii) the high-performance of amorphous oxide semiconductors. From these advances, the challenge of the rational design of novel electroceramic materials is discussed.Comment: Part of a themed issue of Journal of Physics: Condensed Matter on "Semiconducting Oxides". In Press (2011

    Genome sequencing and comparative genomic analysis of highly and weakly aggressive strains of Sclerotium rolfsii, the causal agent of peanut stem rot

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    Background: Stem rot caused by Sclerotium rolfsii is a very important soil-borne disease of peanut. S. rolfsii is a necrotrophic plant pathogenic fungus with an extensive host range and worldwide distribution. It can infect peanut stems, roots, pegs and pods, leading to varied yield losses. S. rolfsii strains GP3 and ZY collected from peanut in different provinces of China exhibited a significant difference in aggressiveness on peanut plants by artificial inoculation test. In this study, de-novo genome sequencing of these two distinct strains was performed aiming to reveal the genomic basis of difference in aggressiveness. Results: Scleotium rolfsii strains GP3 and ZY, with weak and high aggressiveness on peanut plants, exhibited similar growth rate and oxalic acid production in laboratory. The genomes of S. rolfsii strains GP3 and ZY were sequenced by Pacbio long read technology and exhibited 70.51 Mb and 70.61 Mb, with contigs of 27 and 23, and encoded 17, 097 and 16,743 gene models, respectively. Comparative genomic analysis revealed that the pathogenicity-related gene repertoires, which might be associated with aggressiveness, differed between GP3 and ZY. There were 58 and 45 unique pathogen-host interaction (PHI) genes in GP3 and ZY, respectively. The ZY strain had more carbohydrateactive enzymes (CAZymes) in its secretome than GP3, especially in the glycoside hydrolase family (GH), the carbohydrate esterase family (CBM), and the polysaccharide lyase family (PL). GP3 and ZY also had different effector candidates and putative secondary metabolite synthetic gene clusters. These results indicated that differences in PHI, secreted CAZymes, effectors and secondary metabolites may play important roles in aggressive difference between these two strains. Conclusions: The data provided a further understanding of the S. rolfsii genome. Genomic comparison provided clues to the difference in aggressiveness of S. rolfsii strains

    Genome‐wide expression quantitative trait locus analysis in a recombinant inbred line population for trait dissection in peanut

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    The transcriptome connects genome to the gene function and ultimate phenome in biology. Sofar, transcriptomic approach was not used in peanut for performing trait mapping in bi-parentalpopulations. In this research, we sequenced the whole transcriptome in immature seeds in apeanut recombinant inbred line (RIL) population and explored thoroughly the landscape oftranscriptomic variations and its genetic basis. The comprehensive analysis identified total49 691 genes in RIL population, of which 92 genes followed a paramutation-like expressionpattern. Expression quantitative trait locus (eQTL) analysis identified 1207 local eQTLs and15 837 distant eQTLs contributing to the whole-genome transcriptomic variation in peanut.There were 94 eQTL hot spot regions detected across the genome with the dominance of distanteQTL. By integrating transcriptomic profile and annotation analyses, we unveiled a putativecandidate gene and developed a linked marker InDel02 underlying a major QTL responsible forpurple testa colour in peanut. Our result provided a first understanding of genetic basis of whole-genome transcriptomic variation in peanut and illustrates the potential of the transcriptome-aidapproach in dissecting important traits in non-model plants

    Dissection of the genetic basis of oil content in Chinese peanut cultivars through association mapping

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    Background: Peanut is one of the primary sources for vegetable oil worldwide, and enhancing oil content is the main objective in several peanut breeding programs of the world. Tightly linked markers are required for faster development of high oil content peanut varieties through genomics-assisted breeding (GAB), and association mapping is one of the promising approaches for discovery of such associated markers. Results: An association mapping panel consisting of 292 peanut varieties extensively distributed in China was phenotyped for oil content and genotyped with 583 polymorphic SSR markers. These markers amplified 3663 alleles with an average of 6.28 alleles per locus. The structure, phylogenetic relationship, and principal component analysis (PCA) indicated two subgroups majorly differentiating based on geographic regions. Genome-wide association analysis identified 12 associated markers including one (AGGS1014_2) highly stable association controlling up to 9.94% phenotypic variance explained (PVE) across multiple environments. Interestingly, the frequency of the favorable alleles for 12 associated markers showed a geographic difference. Two associated markers (AGGS1014_2 and AHGS0798) with 6.90–9.94% PVE were verified to enhance oil content in an independent RIL population and also indicated selection during the breeding program. Conclusion: This study provided insights into the genetic basis of oil content in peanut and verified highly associated two SSR markers to facilitate marker-assisted selection for developing high-oil content breeding peanut varieties

    A clinical prediction rule for diagnosing human infections with avian influenza A(H7N9) in a hospital emergency department setting

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    BACKGROUND: Human infections with avian influenza A(H7N9) virus are associated with severe illness and high mortality. To better inform triage decisions of hospitalization and management, we developed a clinical prediction rule for diagnosing patients with A(H7N9) and determined its predictive performance. METHODS: Clinical details on presentation of adult patients hospitalized with either A(H7N9)(n = 121) in China from March to May 2013 or other causes of acute respiratory infections (n = 2,603) in Jingzhou City, China from January 2010 through September 2012 were analyzed. A clinical prediction rule was developed using a two-step coefficient-based multivariable logistic regression scoring method and evaluated with internal validation by bootstrapping. RESULTS: In step 1, predictors for A(H7N9) included male sex, poultry exposure history, and fever, haemoptysis, or shortness of breath on history and physical examination. In step 2, haziness or pneumonic consolidation on chest radiographs and leukopenia were also associated with a higher probability of A(H7N9). The observed risk of A(H7N9) was 0.3% for those assigned to the low-risk group and 2.5%, 4.3%, and 44.0% for tertiles 1 through 3, respectively, in the high-risk group. This prediction rule achieved good model performance, with an optimism-corrected sensitivity of 0.93, a specificity of 0.80, and an area under the receiver-operating characteristic curve of 0.96. CONCLUSIONS: A simple decision rule based on data readily obtainable in the setting of patients' first clinical presentations from the first wave of the A/H7N9 epidemic in China has been developed. This prediction rule has achieved good model performance in predicting their risk of A(H7N9) infection and should be useful in guiding important clinical and public health decisions in a timely and objective manner. Data to be gathered with its use in the current evolving second wave of the A/H7N9 epidemic in China will help to inform its performance in the field and contribute to its further refinement.published_or_final_versio

    Charge and Spin Transport in Magnetic Tunnel Junctions: Microscopic Theory

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    We study the charge and spin currents passing through a magnetic tunnel junction (MTJ) on the basis of a tight-binding model. The currents are evaluated perturbatively with respect to the tunnel Hamiltonian. The charge current has the form A[M1(t)×M˙1(t)]M2+BM˙1(t)M2A[\bm M_1(t)\times\dot{\bm M}_1(t)]\cdot\bm M_2+B\dot{\bm M}_1(t)\cdot\bm M_2, where M1(t)\bm M_1(t) and M2\bm M_2 denote the directions of the magnetization in the free layer and fixed layer, respectively. The constant AA vanishes when one or both layers are insulators, {while the constant BB disappears when both layers are insulators or the same ferromagnets.} The first term in the expression for charge current represents dissipation driven by the effective electric field induced by the dynamic magnetization. In addition, from an investigation of the spin current, we obtain the microscopic expression for the enhanced Gilbert damping constant Δα\varDelta \alpha. We show that Δα\varDelta\alpha is proportional to the tunnel conductance and depends on the bias voltage.Comment: 13 pages, 1 figure, accepted for publication in Journal of the Physical Society of Japa
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