357 research outputs found

    An Approach to Agent-Based Service Composition and Its Application to Mobile

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    This paper describes an architecture model for multiagent systems that was developed in the European project LEAP (Lightweight Extensible Agent Platform). Its main feature is a set of generic services that are implemented independently of the agents and can be installed into the agents by the application developer in a flexible way. Moreover, two applications using this architecture model are described that were also developed within the LEAP project. The application domain is the support of mobile, virtual teams for the German automobile club ADAC and for British Telecommunications

    Correlated rigidity percolation and colloidal gels

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    Rigidity percolation (RP) occurs when mechanical stability emerges in disordered networks as constraints or components are added. Here we discuss RP with structural correlations, an effect ignored in classical theories albeit relevant to many liquid-to-amorphous-solid transitions, such as colloidal gelation, which are due to attractive interactions and aggregation. Using a lattice model, we show that structural correlations shift RP to lower volume fractions. Through molecular dynamics simulations, we show that increasing attraction in colloidal gelation increases structural correlation and thus lowers the RP transition, agreeing with experiments. Hence colloidal gelation can be understood as a RP transition, but occurs at volume fractions far below values predicted by the classical RP, due to attractive interactions which induce structural correlation

    Identification of p53-target genes in human papillomavirus-associated head and neck cancer by integrative bioinformatics analysis

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    Introduction: Head and neck cancer (HNC) is a highly prevalent and heterogeneous malignancy. Although extensive efforts have been made to advance its treatment, the prognosis remained poor with increased mortality. Human papillomaviruses (HPV) have been associated with high risk in HNC. TP53, a tumor suppressor, is the most frequently altered gene in HNC, therefore, investigating its target genes for the identification of novel biomarkers or therapeutic targets in HPV-related HNC progression is highly recommended. Methods: Transcriptomic profiles from three independent gene expression omnibus (GEO) datasets, including 44 HPV+ and 70 HPV- HNC patients, were subjected to integrative statistical and Bioinformatics analyses. For the top-selected marker, further in-silico validation in TCGA and GTEx databases and experimental validation in 65 (51 HPV- and 14 HPV+) subjects with histologically confirmed head and neck squamous cell carcinoma (HNSCC) have been performed. Results: A total of 498 differentially expressed genes (DEGs) were identified including 291 up-regulated genes and 207 down-regulated genes in HPV+ compared to HPV- HNSCC patients. Functional annotations and gene set enrichment analysis (GSEA) showed that the up-regulated genes were significantly involved in p53-related pathways. The integrative analysis between the Hub-genes identified in the complex protein-protein network and the top frequent genes resulting from GSEA showed an intriguing correlation with five biomarkers which are EZH2, MDM2, PCNA, STAT5A and TYMS. Importantly, the MDM2 gene showed the highest gene expression difference between HPV+ and HPV- HNSCC (Average log2FC = 1.89). Further in-silico validation in a large HNSCC cohort from TCGA and GTEx databases confirmed the over-expression of MDM2 in HPV+ compared to HPV- HNSCC patients (p = 2.39E-05). IHC scoring showed that MDM2 protein expression was significantly higher in HPV+ compared to HPV- HNSCC patients (p = 0.031). Discussion: Our findings showed evidence that over-expression of MDM2, proto-oncogene, may affect the occurrence and proliferation of HPV-associated HNSCC by disturbing the p53-target genes and consequently the p53-related pathways

    The LINC complex, mechanotransduction, and mesenchymal stem cell function and fate

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    Mesenchymal stem cells (MSCs) show tremendous promise as a cell source for tissue engineering and regenerative medicine, and are understood to be mechanosensitive to external mechanical environments. In recent years, increasing evidence points to nuclear envelope proteins as a key player in sensing and relaying mechanical signals in MSCs to modulate cellular form, function, and differentiation. Of particular interest is the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex that includes nesprin and SUN. In this review, the way in which cells can sense external mechanical environments through an intact nuclear envelope and LINC complex proteins will be briefly described. Then, we will highlight the current body of literature on the role of the LINC complex in regulating MSC function and fate decision, without and with external mechanical loading conditions. Our review and suggested future perspective may provide a new insight into the understanding of MSC mechanobiology and related functional tissue engineering applications

    Optimal Byzantine Resilient Convergence in Asynchronous Robot Networks

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    We propose the first deterministic algorithm that tolerates up to ff byzantine faults in 3f+13f+1-sized networks and performs in the asynchronous CORDA model. Our solution matches the previously established lower bound for the semi-synchronous ATOM model on the number of tolerated Byzantine robots. Our algorithm works under bounded scheduling assumptions for oblivious robots moving in a uni-dimensional space

    A new experiment for the determination of the 18F(p,alpha) reaction rate at nova temperatures

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    The 18F(p,alpha) reaction was recognized as one of the most important for gamma ray astronomy in novae as it governs the early 511 keV emission. However, its rate remains largely uncertain at nova temperatures. A direct measurement of the cross section over the full range of nova energies is impossible because of its vanishing value at low energy and of the short 18F lifetime. Therefore, in order to better constrain this reaction rate, we have performed an indirect experiment taking advantage of the availability of a high purity and intense radioactive 18F beam at the Louvain La Neuve RIB facility. We present here the first results of the data analysis and discuss the consequences.Comment: Contribution to the Classical Novae Explosions conference, Sitges, Spain, 20-24 May 2002, 5 pages, 3 figure

    Public health interventions for Aedes control in the time of Zikavirus- A metareview on effectiveness of vector control strategies

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    Background: There is renewed interest in effective control measures to control Zika and dengue vectors. A synthesis of published systematic reviews with a focus on grading of intervention evidence is warranted to determine the reliability of evidence for control strategies. Methodology: We conducted a meta-review (a systematic review of systematic reviews) assessing the effectiveness of any Aedes control measure. We searched Scopus and Medline for relevant reviews through to 11 May 2016. Titles, abstracts and full texts were assessed independently for inclusion by two authors. Data extraction was performed independently in duplicate using a standardised form and validity of the evidence in each review was assessed using GRADE criteria. Findings: 13 eligible systematic reviews that investigated the effect of community interventions on entomological parameters (such as vector density) or disease incidence were included. Quality of evidence was mostly low to very low due to poor reporting of study design, observational methodologies, heterogeneity, and indirect outcomes, hindering an evidence-based recommendation. Biological controls seem to achieve better reduction of entomological indices than chemical controls, while educational campaigns can reduce breeding habitats and interrupt disease transmission cycle. Integrated control strategies may not add efficiency to educational campaigns. Conclusions: Despite decades of Aedes mosquito abatement programmes, mosquito populations are widely established and abundant, and associated with a significant disease burden. The efficiency of any control programme is dependent on local settings and resources. More good quality primary studies for the control of Aedes transmitted diseases are still required

    Indirect study of 19Ne states near the 18F+p threshold

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    The early E < 511 keV gamma-ray emission from novae depends critically on the 18F(p,a)15O reaction. Unfortunately the reaction rate of the 18F(p,a)15O reaction is still largely uncertain due to the unknown strengths of low-lying proton resonances near the 18F+p threshold which play an important role in the nova temperature regime. We report here our last results concerning the study of the d(18F,p)19F(alpha)15N transfer reaction. We show in particular that these two low-lying resonances cannot be neglected. These results are then used to perform a careful study of the remaining uncertainties associated to the 18F(p,a)15O and 18F(p,g)19Ne reaction rates.Comment: 18 pages, 8 figures. Accepted in Nuclear Physics

    The STAFF-DWP wave instrument on the DSP equatorial spacecraft: description and first results

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    The STAFF-DWP wave instrument on board the equatorial spacecraft (TC1) of the Double Star Project consists of a combination of 2&amp;nbsp;instruments which are a heritage of the Cluster mission: the Spatio-Temporal Analysis of Field Fluctuations (STAFF) experiment and the Digital Wave-Processing experiment (DWP). On DSP-TC1 STAFF consists of a three-axis search coil magnetometer, used to measure magnetic fluctuations at frequencies up to 4 kHz and a waveform unit, up to 10 Hz, plus snapshots up to 180 Hz. DWP provides several onboard analysis tools: a complex FFT to fully characterise electromagnetic waves in the frequency range 10 Hz-4 kHz, a particle correlator linked to the PEACE electron experiment, and compression of the STAFF waveform data. The complementary Cluster and TC1 orbits, together with the similarity of the instruments, permits new multi-point studies. The first results show the capabilities of the experiment, with examples in the different regions of the magnetosphere-solar wind system that have been encountered by DSP-TC1 at the beginning of its operational phase. An overview of the different kinds of electromagnetic waves observed on the dayside from perigee to apogee is given, including the different whistler mode waves (hiss, chorus, lion roars) and broad-band ULF emissions. The polarisation and propagation characteristics of intense waves in the vicinity of a bow shock crossing are analysed using the dedicated PRASSADCO tool, giving results compatible with previous studies: the broad-band ULF waves consist of a superimposition of different wave modes, whereas the magnetosheath lion roars are right-handed and propagate close to the magnetic field. An example of a combined Cluster DSP-TC1 magnetopause crossing is given. This first case study shows that the ULF wave power intensity is higher at low latitude (DSP) than at high latitude (Cluster). On the nightside in the tail, a first wave event comparison - in a rather quiet time interval - is shown. It opens the doors to future studies, such as event timing during substorms, to possibly determine their onset location
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