4,738 research outputs found

    Classical and Non-Relativistic Limits of a Lorentz-Invariant Bohmian Model for a System of Spinless Particles

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    A completely Lorentz-invariant Bohmian model has been proposed recently for the case of a system of non-interacting spinless particles, obeying Klein-Gordon equations. It is based on a multi-temporal formalism and on the idea of treating the squared norm of the wave function as a space-time probability density. The particle's configurations evolve in space-time in terms of a parameter {\sigma}, with dimensions of time. In this work this model is further analyzed and extended to the case of an interaction with an external electromagnetic field. The physical meaning of {\sigma} is explored. Two special situations are studied in depth: (1) the classical limit, where the Einsteinian Mechanics of Special Relativity is recovered and the parameter {\sigma} is shown to tend to the particle's proper time; and (2) the non-relativistic limit, where it is obtained a model very similar to the usual non-relativistic Bohmian Mechanics but with the time of the frame of reference replaced by {\sigma} as the dynamical temporal parameter

    Optimization of Quercetin Extraction from Green Tea (Camellia sinensis) Using Central Composite Design, and the Pharmacological Activity of the Extract

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    The aim of this paper was to optimize an extraction procedure of quercetin from green tea using central composite design. Extraction time, ethanol concentration, and solid to liquid ratio were selected as the independent variables, while quercetin yield was defined as a response. The impact of factors and their interactions on the quercetin yield was studied based on the results of ANOVA test. The extraction time of 58.5 min, ethanol concentration of 94.7 % (v/v), and solid to liquid ratio of 1:19.4 (m/v) were found as the optimal conditions. The experimental confirmation of the proposed optimal conditions indicated that there was a good agreement between the experimental and predicted values. In addition to quercetin, the presence of 17 bioactive compounds was confirmed in the green tea extract using mass spectrometry method. Antioxidant, antimicrobial and antitumor activity of the optimal extract was determined using DPPH assay, disk diffusion method, and MTT assay, respectively

    Reparatory and Manufacturing Hard-Facing of Working Parts Made of Stainless Steels in Confectionary Industry

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    In this paper, for the sake of improving the reparatory hard-facing technology is especially analyzed reparatory hard-facing of tools for manufacturing compressed products in confectionary industry. Those products are being made of a mixture consisting of several powdery components, which is compressed under high pressure. In that way the connection between particles is realized, thus achieving certain hardness and strength of the confectionary product. The considered tool is made of high-alloyed stainless steel. The tool contains 30 identical working places. Besides the production process wear, on those tools, from time to time, appear mechanical damage on some of the products' shape punches, as cracks at the edges, where the products' final shapes are formed. Those damages are small, size wise, but they cause strong effect on the products' final shape. The aggravating circumstance is that the shape punch is extremely loaded in pressure, thus after the reparatory hard-facing, the additional heat treatment is necessary. Mechanical properties in the heat affected zone (HAZ) are being leveled by annealing and what also partially reduces the residual internal stresses

    Star Formation Near Photodissociation Regions: Detection of a Peculiar Protostar Near Ced 201

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    We present the detection and characterization of a peculiar low-mass protostar (IRAS 22129+7000) located ~0.4 pc from Ced 201 Photodissociation Region (PDR) and ~0.2 pc from the HH450 jet. The cold circumstellar envelope surrounding the object has been mapped through its 1.2 mm dust continuum emission with IRAM-30m/MAMBO. The deeply embedded protostar is clearly detected with Spitzer/MIPS (70 um), IRS (20-35 um) and IRAC (4.5, 5.8, and 8 um) but also in the K_s band (2.15 um). Given the large "near- and mid-IR excess" in its spectral energy distribution, but large submillimeter-to-bolometric luminosity ratio (~2%), IRAS 22129+7000 must be a transition Class 0/I source and/or a multiple stellar system. Targeted observations of several molecular lines from CO, 13CO, C18O, HCO+ and DCO+ have been obtained. The presence of a collimated molecular outflow mapped with the CSO telescope in the CO J=3-2 line suggests that the protostar/disk system is still accreting material from its natal envelope. Indeed, optically thick line profiles from high density tracers such as HCO+ J=1-0 show a red-shifted-absorption asymmetry reminiscent of inward motions. We construct a preliminary physical model of the circumstellar envelope (including radial density and temperature gradients, velocity field and turbulence) that reproduces the observed line profiles and estimates the ionization fraction. The presence of both mechanical and (non-ionizing) FUV-radiative input makes the region an interesting case to study triggered star formation

    Status of the High Field Cable Test Facility at Fermilab

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    Fermi National Accelerator Laboratory (FNAL) and Lawrence Berkeley National Laboratory (LBNL) are building a new High Field Vertical Magnet Test Facility (HFVMTF) for testing superconducting cables in high magnetic field. The background magnetic field of 15 T in the HFVMTF will be produced by a magnet provided by LBNL. The HFVMTF is jointly funded by the US DOE Offices of Science, High Energy Physics (HEP), and Fusion Energy Sciences (FES), and will serve as a superconducting cable test facility in high magnetic fields and a wide range of temperatures for HEP and FES communities. This facility will also be used to test high-field superconducting magnet models and demonstrators, including hybrid magnets, produced by the US Magnet Development Program (MDP). The paper describes the status of the facility, including construction, cryostat designs, top and lambda plates, and systems for powering, and quench protection and monitoring

    Liraglutide Reduces Carotid Intima-Media Thickness by Reducing Small Dense Low-Density Lipoproteins in a Real-World Setting of Patients with Type 2 Diabetes: A Novel Anti-Atherogenic Effect

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    Introduction: Liraglutide has several non-glycemic effects, including those on plasma lipids and lipoproteins, contributing to its cardiovascular benefit; however, the exact underlying mechanisms remain unclear. We investigated a novel anti-atherogenic effect of liraglutide in a real-world prospective study on patients with type 2 diabetes (T2DM). Methods: Sixty-two patients with T2DM (31 men, 31 women; mean age ± standard deviation 61 ± 9 years) naĂŻve to incretin-based therapies were treated with liraglutide (1.2 mg/day) as add-on therapy to metformin (1500–3000 mg/day) for 4 months. Laboratory analyses included the assessment of lipoprotein subclass profile by gel electrophoresis (Lipoprint; Quantimetrix Corp., Redondo Beach, CA, USA). Carotid intima-media thickness (cIMT) was assessed by Doppler ultrasonography. Statistical analyses included the paired t test, Spearman correlation and multiple regression analysis. Results: The addition of liraglutide to metformin monotherapy resulted in significant reductions in fasting glycemia, hemoglobin A1c, body mass index, waist circumference, total cholesterol, triglycerides and low-density lipoprotein (LDL)-cholesterol, as well as in cIMT. There was an increase in the large LDL-1 subfraction, with a concomitant reduction in atherogenic small dense LDL-3 and LDL-4 subfractions. Correlation analysis revealed a significant association between changes in cIMT and changes in small dense LDL-3 subfraction (r = 0.501; p < 0.0001). Multivariate analysis, including all of the measured anthropometric and laboratory parameters, revealed that only changes in the small dense LDL-3 subfraction were independent predictors of changes in cIMT (p < 0.0001). Conclusion: Our findings are the first to show that the vascular benefit of liraglutide in patients with T2DM is associated with reductions in atherogenic small dense LDL. This effect is independent of glycemic control and body weight reduction and may represent one of the key mechanisms by which liraglutide is able to reduce cardiovascular events. Trial Registration: ClinicalTrials.gov: NCT01715428

    Monitoring the CMS strip tracker readout system

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    The CMS Silicon Strip Tracker at the LHC comprises a sensitive area of approximately 200 m2 and 10 million readout channels. Its data acquisition system is based around a custom analogue front-end chip. Both the control and the readout of the front-end electronics are performed by off-detector VME boards in the counting room, which digitise the raw event data and perform zero-suppression and formatting. The data acquisition system uses the CMS online software framework to configure, control and monitor the hardware components and steer the data acquisition. The first data analysis is performed online within the official CMS reconstruction framework, which provides many services, such as distributed analysis, access to geometry and conditions data, and a Data Quality Monitoring tool based on the online physics reconstruction. The data acquisition monitoring of the Strip Tracker uses both the data acquisition and the reconstruction software frameworks in order to provide real-time feedback to shifters on the operational state of the detector, archiving for later analysis and possibly trigger automatic recovery actions in case of errors. Here we review the proposed architecture of the monitoring system and we describe its software components, which are already in place, the various monitoring streams available, and our experiences of operating and monitoring a large-scale system

    Irreducible Representations of Diperiodic Groups

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    The irreducible representations of all of the 80 diperiodic groups, being the symmetries of the systems translationally periodical in two directions, are calculated. To this end, each of these groups is factorized as the product of a generalized translational group and an axial point group. The results are presented in the form of the tables, containing the matrices of the irreducible representations of the generators of the groups. General properties and some physical applications (degeneracy and topology of the energy bands, selection rules, etc.) are discussed.Comment: 30 pages, 5 figures, 28 tables, 18 refs, LaTex2.0
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