Velocity distribution of fragments of catastrophic impacts

Three dimensional velocities of fragments produced by laboratory impact experiments were measured for basalts and pyrophyllites. The velocity distribution of fragments obtained shows that the velocity range of the major fragments is rather narrow, at most within a factor of 3 and that no clear dependence of velocity on the fragment mass is observed. The NonDimensional Impact Stress (NDIS) defined by Mizutani et al. (1990) is found to be an appropriate scaling parameter to describe the overall fragment velocity as well as the antipodal velocity

Simple algorithm for judging equivalence of differential-algebraic equation systems

Mathematical formulas play a prominent role in science, technology, engineering, and mathematics (STEM) documents; understanding STEM documents usually requires knowing the difference between equation groups containing multiple equations. When two equation groups can be transformed into the same form, we call the equation groups equivalent. Existing tools cannot judge the equivalence of two equation groups; thus, we develop an algorithm to judge such an equivalence using a computer algebra system. The proposed algorithm first eliminates variables appearing only in either equation group. It then checks the equivalence of the equations one by one: the equations with identical algebraic solutions for the same variable are judged equivalent. If each equation in one equation group is equivalent to an equation in the other, the equation groups are judged equivalent; otherwise, non-equivalent. We generated 50 pairs of equation groups for evaluation. The proposed method accurately judged the equivalence of all pairs. This method is expected to facilitate comprehension of a large amount of mathematical information in STEM documents. Furthermore, this is a necessary step for machines to understand equations, including process models

A generalized Weyl relation approach to the time operator and its connection to the survival probability

The time operator, an operator which satisfies the canonical commutation relation with the Hamiltonian, is investigated, on the basis of a certain algebraic relation for a pair of operators T and H, where T is symmetric and H self-adjoint. This relation is equivalent to the Weyl relation, in the case of self-adjoint T, and is satisfied by the Aharonov-Bohm time operator T_0 and the free Hamiltonian H_0 for the one-dimensional free-particle system. In order to see the qualitative properties of T_0, the operators T and H satisfying this algebraic relation are examined. In particular, it is shown that the standard deviation of T is directly connected to the survival probability, and H is absolutely continuous. Hence, it is concluded that the existence of the operator T implies the existence of scattering states. It is also shown that the minimum uncertainty states do not exist. Other examples of these operators T and H, than the one-dimensional free-particle system, are demonstrated.Comment: 16 pages, REVTeX. Accepted for publication in the Journal of Mathematical Physic

Cheon's anholonomies in Floquet operators

Anholonomies in the parametric dependences of the eigenvalues and the eigenvectors of Floquet operators that describe unit time evolutions of periodically driven systems, e.g., kicked rotors, are studied. First, an example of the anholonomies induced by a periodically pulsed rank-1 perturbation is given. As a function of the strength of the perturbation, the perturbed Floquet operator of the quantum map and its spectrum are shown to have a period. However, we show examples where each eigenvalue does not obey the periodicity of the perturbed Floquet operator and exhibits an anholonomy. Furthermore, this induces another anholonomy in the eigenspaces, i.e., the directions of the eigenvectors, of the Floquet operator. These two anholonomies are previously observed in a family of Hamiltonians [T. Cheon, Phys. Lett. A 248, 285 (1998)] and are different from the phase anholonomy known as geometric phases. Second, the stability of Cheon's anholonomies in periodically driven systems is established by a geometrical analysis of the family of Floquet operators. Accordingly, Cheon's anholonomies are expected to be abundant in systems whose time evolutions are described by Floquet operators. As an application, a design principle for quantum state manipulations along adiabatic passages is explained

Comparative Efficacy and Safety of Linezolid and Quinupristin-Dalfopristin in the Treatment of Vancomycin-Resistant Enterococcus Infections: A Meta-Analysis

Introduction: Vancomycin-resistant Enterococcus (VRE) is one of the most important causative organisms of nosocomial infections. Once VRE outbreaks occur in hospitals, enormous efforts must be made to control them, especially in wards housing neutropenic or transplant patients. The purpose of this meta-analysis was to investigate the efficacy and adverse event profile of linezolid versus that of Quinupristin-Dalfopristin for the treatment of VRE infections.Methodology: Literature searches of PubMed, MEDLINE, and EMBASE databases were performed on April 5, 2017 using combined text words with the following MeSH/EMTREE terms: “linezolid” and “Quinupristin-Dalfopristin” and “Enterococcus” and “human.” The odds ratios (ORs) with 95% confidence intervals (CIs) for individual studies were calculated and pooled separately. The pooled estimates were combined using the inverse variance weighting scheme and random effect method.Results: A systematic search identified 674 articles, and five involving 333 patients were included in the final analysis. One study was a prospective randomized controlled trial, and four were retrospective studies. The mortality rate in the groups of patients treated with linezolid was significantly lower than that in patients treated with Quinupristin-Dalfopristin (OR: 0.47; 95% CI: 0.23 to 0.97; heterogeneity P=0.13, Z=2.05, P=0.04; I2=44%; Begg’s test: P=0.33; Egger’s test: P=0.78). The clinical and microbiological responses indicated no significant differences between the linezolid and Quinupristin-Dalfopristin groups (58% and 43%, respectively, P=0.6; OR: 1.51; 95% CI: 0.75 to 3.04; heterogeneity P=0.32; Z=1.15, P=0.25; I2=0%). The adverse event proiles differed between the Linezolid and quinupristin-dalfopristin groups.Conclusion: Our results suggest a significantly lower mortality rate in patients treated with linezolid than in those treated with Quinupristin-Dalfopristin for VRE infections; however, this was limited by a variety of factors (mostly retrospective)

NPC1L1 inhibitor ezetimibe is a reliable therapeutic agent for non-obese patients with nonalcoholic fatty liver disease

<p>Abstract</p> <p>Background</p> <p>We recently examined the distribution of abdominal fat, dietary intake and biochemical data in patients with nonalcoholic fatty liver disease (NAFLD) and found that non-obese NAFLD patients did not necessarily exhibit insulin resistance and/or dysregulated secretion of adipocytokines. However, dietary cholesterol intake was superabundant in non-obese patients compared with obese patients, although total energy and carbohydrate intake was not excessive. Therefore, excess cholesterol intake appears to be one of the main factors associated with NAFLD development and liver injury.</p> <p>Methods</p> <p>We reviewed a year of follow-up data of non-obese NAFLD patients treated with Niemann-Pick C1 like 1 inhibitor ezetimibe to evaluate its therapeutic effect on clinical parameters related to NAFLD. Without any dietary or exercise modification, 10 mg/day of ezetimibe was given to 8 patients. In 4 of 8 patients, ezetimibe was administered initially. In the remaining 4 patients, medication was switched from ursodeoxycholic acid to ezetimibe.</p> <p>Results</p> <p>In each patient, body mass index was maintained under 25 kg/m²during the observation period. Serum ALT levels significantly decreased within 6 months and in 4 patients levels reached the normal range (<30 U/L), which was accompanied with at least a 10% decrease in serum total cholesterol and LDL-cholesterol. However, ultrasonographic findings of fatty liver did not show obvious improvement for a year.</p> <p>Conclusion</p> <p>We conclude that the cholesterol absorption inhibitor ezetimibe can suppress hepatic injury in non-obese patients with NAFLD and that ezetimibe may offer a novel treatment for NAFLD.</p