1,410 research outputs found
Epidemic and timer-based message dissemination in VANETs: A performance comparison
Data dissemination is among the key functions of Vehicular Ad-Hoc Networks (VANETs), and it has attracted much attention in the past decade. We address distributed, efficient, and scalable algorithms in the context of VANETs adopting the paradigm. We introduce an epidemic algorithm for message dissemination. The algorithm, named EPIC, is based on few assumptions, and it is very simple to implement. It uses only local information at each node, broadcast communications, and timers. EPIC is designed with the goal to reach the highest number of vehicles “infected” by the message, without overloading the network. It is tested on different scenarios taken from VANET simulations based on real urban environments (Manhattan, Cologne, Luxembourg). We compare our algorithm with a standard-based solution that exploits the contention-based forwarding component of the ETSI GeoNetworking protocol. On the other hand, we adapt literature based on a connected cover set to assess the near-optimality of our proposed algorithm and gain insight into the best selection of relay nodes as the size of the graph over which messages are spread scales up. The performance evaluation shows the behavior of EPIC and allows us to optimize the protocol parameters to minimize delay and overhead
Complexity reduction of astrochemical networks
We present a new computational scheme aimed at reducing the complexity of the
chemical networks in astrophysical models, one which is shown to markedly
improve their computational efficiency. It contains a flux-reduction scheme
that permits to deal with both large and small systems. This procedure is shown
to yield a large speed-up of the corresponding numerical codes and provides
good accord with the full network results. We analyse and discuss two examples
involving chemistry networks of the interstellar medium and show that the
results from the present reduction technique reproduce very well the results
from fuller calculations.Comment: 9 pages, 7 figures, accepted for publication in Monthly Notices of
the Royal Astronomical Society Main Journa
Recent advances in targeting protein arginine methyltransferase enzymes in cancer therapy
Introduction: Exploration in the field of epigenetics has revealed the diverse roles of the protein arginine methyltransferase (PRMT) family of proteins in multiple disease states. These findings have led to the development of specific inhibitors and discovery of several new classes of drugs with potential to treat both benign and malignant conditions. Areas covered: We provide an overview on the role of PRMT enzymes in healthy and malignant cells, highlighting the role of arginine methylation in specific pathways relevant to cancer pathogenesis. Additionally, we describe structure and catalytic activity of PRMT and discuss the mechanisms of action of novel small molecule inhibitors of specific members of the arginine methyltransferase family. Expert opinion: As the field of PRMT biology advances, it’s becoming clear that this class of enzymes is highly relevant to maintaining normal physiologic processes as well and disease pathogenesis. We discuss the potential impact of PRMT inhibitors as a broad class of drugs, including the pleiotropic effects, off target effects the need for more detailed PRMT-centric interactomes, and finally, the potential for targeting this class of enzymes in clinical development of experimental therapeutics for cancer. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.The study was funded by the Qatar National Research Fund (QNRF) through the National Priorities Research Program (NPRP) grant [NPRP8-617-3-131].Scopu
Multimodal treatment of gastric cancer in the west: Where are we going?
The incidence of gastric cancer (GC) is decreasing worldwide, especially for intestinal histotype of the distal third of the stomach. On the contrary, proximal location and diffuse Lauren histotype have been reported to be generally stable over time. In the west, no clear improvement in long-term results was observed in clinical and population-based studies. Results of treatment in these neoplasms are strictly dependent on tumor stage. Adequate surgery and extended lymphadenectomy are associated with good long-term outcome in early-stage cancer; however, results are still unsatisfactory for advanced stages (III and IV), for which additional treatments could provide a survival benefit. This implies a tailored approach to GC. The aim of this review was to summarize the main multimodal treatment options in advanced resectable GC. Perioperative or postoperative treatments, including chemotherapy, chemoradiotherapy, targeted therapies, and hyperthermic intraperitoneal chemotherapy have been reviewed, and the main ongoing and completed trials have been analyzed. An original tailored multimodal approach to non-cardia GC has been also proposed
Habsburg topographic cartography of the Italian peninsula in the first half of the 19th century
The geodetic point lists of the Habsburg survey of the Italian peninsula, carried out in several steps after the Napoleonic wars, were digitized and analyzed together with the modern coordinates of the identified points. Assuming the usage of the Zach-Oriani hybrid ellipsoid, the Burša-Wolf type datum transformation parameters were estimated between the local, historical triangulation Datums and the WGS84. The results show interesting accuracy differences in the Italian regions; since the points and coordinates in Lombardy, Piedmont and Lucca shows surprisingly high accuracy and consistency, the survey of Venice, Tuscany, the Papal State, the Adriatic coasts and the Kingdom of Naples is less controlled. The results enabled us to geo-refer the corresponding map series, stored in the Austrian Military Archives, in Vienna, in four different parts. Venice, Lombardy and Lucca (with other small regions at their southern border) were a part of the Habsburg Second Military Survey, with same scale and technology and legend. Part of the series of Piedmont was also found in the Vienna archives and geo-referred. South of these regions, Tuscany and the Papal State was mapped in 1:86400 scale, in a Cassini projection with the centre in the Duomo S. Salvatore, Milan. The southernmost systematic mapping work in the peninsula was in the Kingdom of Naples in the 1820s, with the same scale as used in mid-Italy, projection centre was in Capodimonte (Naples). Albeit the relatively high accuracy of the geodetic network, these map mosaics are refined horizontally applying a local correction grid (GSB) to keep the horizontal errors below 200 meters
Quasivariational solutions for first order quasilinear equations with gradient constraint
We prove the existence of solutions for an evolution quasi-variational
inequality with a first order quasilinear operator and a variable convex set,
which is characterized by a constraint on the absolute value of the gradient
that depends on the solution itself. The only required assumption on the
nonlinearity of this constraint is its continuity and positivity. The method
relies on an appropriate parabolic regularization and suitable {\em a priori}
estimates. We obtain also the existence of stationary solutions, by studying
the asymptotic behaviour in time. In the variational case, corresponding to a
constraint independent of the solution, we also give uniqueness results
Stabilization arising from PGEM : a review and further developments
The aim of this paper is twofold. First, we review the recent Petrov-Galerkin enriched method (PGEM) to stabilize numerical solutions of BVP's in primal and mixed forms. Then, we extend such enrichment technique to a mixed singularly perturbed problem, namely, the generalized Stokes problem, and focus on a stabilized finite element method arising in a natural way after performing static condensation. The resulting stabilized method is shown to lead to optimal convergences, and afterward, it is numerically validated
Circulating microRNA-23b-3p and tissue microRNA-193a-3p as promising molecular biomarkers in human hepatocellular carcinoma.
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