19,399 research outputs found
Effects of microbus front structure on pedestrian head injury
In order to study the effects of the microbus front structure on pedestrian head injury happened in pedestrian-microbus collisions, the mathematic models of the impact angle and microbus front configuration are developed, which illustrate the relationship between the impact angle, pedestrian size, and oblique angles of the engine hood and windscreen. The mathematic models are then verified by simulating experiments using LY-Dyna. The impact angle α, which is measured between the contact surface and the pedestrian head's impact direction at the contact point, is an important parameter indicating the relationship of pedestrian head injury with the microbus front structure. The analysis and simulation results reveal that (1) in the case of collision with the windscreen, the pedestrian head injury increases while α increases; (2) in the case of collision with the engine hood, the pedestrian head incurs the most serious injury when α = 90o, the pedestrian head injury increases while α increases when α 90o. Six microbus models are taken as examples to verify the results obtained
Simple algebras of Weyl type
Over a field of any characteristic, for a commutative associative algebra
with an identity element and for the polynomial algebra of a
commutative derivation subalgebra of , the associative and the Lie
algebras of Weyl type on the same vector space are
defined. It is proved that , as a Lie algebra (modular its center) or as
an associative algebra, is simple if and only if is -simple and
acts faithfully on . Thus a lot of simple algebras are obtained.Comment: 9 pages, Late
Reply to "Comment on 'Fano resonance for Anderson Impurity Systems' "
In a recent Comment, Kolf et al. (cond-mat/0503669) state that our analysis
of the Fano resonance for Anderson impurity systems [Luo et al., Phys. Rev.
Lett 92, 256602 (2004)] is incorrect. Here we want to point out that their
comments are not based on firm physical results and their criticisms are
unjustified and invalid.Comment: 1 page, 1 figure, to appear in PR
Prognostic Importance of Circulating Tumor Cells in Nonsmall Cell Lung Cancer: A Prospective Study
Purpose: To investigate the prognostic value of circulating tumor cells (CTCs) and to predict the treatment response in a non-small cell lung cancer (NSCLC).Methodology: A single-center prospective study involving 93 patients with NSCLC was conducted. Blood samples were analyzed for CTC count before and after chemotherapy. Clinical relevance of CTCs with patient`s characteristics and treatment response were determined.Results: Higher levels of CTCs were associated with severe stage of NSCLC (p = 0.003), tumor histology (p = 0.014) and metastases (p = 0.013). Significant difference in CTC count was observed in favorable (CTCs < 5) and unfavorable (CTCs ≥ 5) groups. Progression-free survival (PFS) was 5.8 months (range: 5.32 to 6.43) and 2.2 months (range: 1.85 to 3.01) in the favorable and unfavorable groups, respectively (HR: 3.88, 95% CI, p < 0.001). Similarly, overall survival (OS) was 7.3 months (95% CI, 6.51 to 7.92) and 3.9 months (95% CI, 1.99 to 5.13), respectively (HR: 4.8, 95% CI, p < 0.001). Multivariate regression analysis revealed CTCs as strong predictors of OS and PFS. Significant reduction (p < 0.001) in CTC count was also observed after one cycle of chemotherapy.Conclusion: Patients with low CTC count live longer and remain progression-free for a longer period of time than those with high CTC count. High CTCs can be detected in severe forms of lung cancer and can be used as a valid prognostic marker. However, this assertion requires validation in larger prospective clinical cohorts.Keywords: Circulating tumor cells, Non-small cell lung cancer, Circulating tumor cell, Prognosi
Enforcing trustworthy cloud SLA with witnesses: A game theory–based model using smart contracts
There lacks trust between the cloud customer and provider to enforce traditional cloud SLA (Service Level Agreement) where the blockchain technique seems a promising solution. However, current explorations still face challenges to prove that the off-chain SLO (Service Level Objective) violations really happen before recorded into the on-chain transactions. In this paper, a witness model is proposed implemented with smart contracts to solve this trust issue. The introduced role, “Witness”, gains rewards as an incentive for performing the SLO violation report, and the payoff function is carefully designed in a way that the witness has to tell the truth, for maximizing the rewards. This fact that the witness has to be honest is analyzed and proved using the Nash Equilibrium principle of game theory. For ensuring the chosen witnesses are random and independent, an unbiased selection algorithm is proposed to avoid possible collusions. An auditing mechanism is also introduced to detect potential malicious witnesses. Specifically, we define three types of malicious behaviors and propose quantitative indicators to audit and detect these behaviors. Moreover, experimental studies based on Ethereum blockchain demonstrate the proposed model is feasible, and indicate that the performance, ie, transaction fee, of each interface follows the design expectations
Pair creation enhancement due to combined external fields
We study the creation of electron-positron pairs from the vacuum induced by a combination of a static electric field and an alternating field. We find that the overall pair production can be increased by two orders of magnitude compared to the yields associated with each field individually. We examine the interesting case where both fields are spatially localized, permitting us to examine the time evolution of the spatial density for the created particle pairs. We find that there are a variety of competing mechanisms that contribute to the total yield
Strong Dzyaloshinskii-Moriya Interaction and Origin of Ferroelectricity in Cu2OSeO3
By performing density functional calculations, we investigate the origin of
the skyrmion state and ferroelectricity in Cu2OSeO3. We find that the
Dzyaloshinskii-Moriya interactions between the two different kinds of Cu ions
are extremely strong and induce the helical ground state and the skyrmion state
in the absence and presence of magnetic field, respectively. On the basis of
the general model for the spin-order induced polarization, we propose that the
ferroelectric polarization of Cu2OSeO3 in the collinear ferrimagnetic state
arises from an unusual mechanism, i.e., the single-spin-site contribution due
to the spin-orbit coupling
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