889 research outputs found
Impact on survival of the number of lymph nodes resected in patients with lymph node-negative gastric cancer
BACKGROUND: Patients with lymph node-negative gastric cancer show a better overall survival rate than those who have a pathological lymph node-positive gastric cancer. But a large number of patients still develop recurrence. We aimed to explore the significant prognostic factors of lymph node-negative gastric cancer and determine how many lymph nodes should be removed.
METHODS: A total of 3103 patients who underwent radical operation are identified from the Surveillance, Epidemiology, and End Results database. Standard survival methods and restricted multivariable Cox regression models were applied.
RESULTS: The overall survival rate was significantly higher with an increasing number of negative lymph node resected. Among the 843 patients who had the exact T stage, the overall survival rate was significantly better in T3-4 group with more than 15 lymph nodes resected (P \u3c 0.001) but not in T1-2 stage patients (P = 0.44). A further 25 more lymph nodes resection did not show additional survival benefits. Multivariate analysis of patients demonstrated that age, depth of tumor invasion, and the number of lymph nodes resected were the significant and independent prognostic factors.
CONCLUSIONS: A lymphadenectomy with more than 15 lymph nodes removal should be performed for T3-4 lymph node-negative gastric cancer. But the survival benefit of a lymphadenectomy with more than 25 lymph nodes removal is disputed. And the further treatment should refer to the prognostic indicators
Analytic Computation of three-point energy correlator in QCD
The energy correlator measures the energy deposited in multiple detectors as a function of the angles among them. In this paper, an analytic formula is given for the three-point energy correlator with full angle dependence at leading order in electron-positron annihilation. This is the first analytic computation of trijet event shape observables in QCD, which provides valuable data for phenomenological studies. The result is computed with direct integration, where appropriate parameterizations of both phase space and kinematic space are adopted to simplify the calculation. With full shape dependence, our result provides the expansions in various kinematic regions such as equilateral, triple collinear and squeezed limits, which benefit studies on both factorization and large logarithm resummation
Exploiting Traffic Balancing and Multicast Efficiency in Distributed Video-on-Demand Architectures
Distributed Video-on-Demand (DVoD) systems are proposed as a
solution to the limited streaming capacity and null scalability of centralized
systems. In a previous work, we proposed a fully distributed large-scale VoD
architecture, called Double P-Tree, which has shown itself to be a good approach
to the design of flexible and scalable DVoD systems. In this paper, we
present relevant design aspects related to video mapping and traffic balancing in
order to improve Double P-Tree architecture performance. Our simulation results
demonstrate that these techniques yield a more efficient system and considerably
increase its streaming capacity. The results also show the crucial importance
of topology connectivity in improving multicasting performance in
DVoD systems. Finally, a comparison among several DVoD architectures was
performed using simulation, and the results show that the Double P-Tree architecture
incorporating mapping and load balancing policies outperforms similar
DVoD architectures.This work was supported by the MCyT-Spain under contract TIC 2001-2592 and partially supported by the Generalitat de Catalunya- Grup de Recerca Consolidat 2001SGR-00218
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