170 research outputs found

    Stationary states of open XX-spin chains

    Get PDF
    We study an open quantum spin chain of arbitrary length with nearest neighbor X X interactions of strength g, immersed in an external constant magnetic field Δ along the z direction, whose end spins are weakly coupled to two heat baths at different temperatures. In the so-called global approach, namely, without neglecting interspin interactions, using standard weak-coupling limit techniques, we first derive the open chain master equation written in terms of fermionic mode operators. Then, we focus on the study of the dependence of the resulting open dynamics from the ratio r ≡ g/Δ. By increasing r, some of the chain Bohr transition frequencies become negative; when this occurs, both the generator of the dissipative time evolution and its stationary states behave discontinuously. As a consequence, the asymptotic spin and heat flows also exhibit discontinuities, but in a different way: while source terms in the spin flow continuity equation show jumps, the heat flow instead is continuous but with discontinuous first derivatives with respect to r. These two behaviors might be experimentally accessible; in particular, they could discriminate between the global and the local approaches to open quantum spin chains. Indeed, the latter one, which neglects interspin interactions in the derivation of the master equation, does not show any kind of discontinuous behavior

    Evaluating the Conventional Pushover Procedures for Estimating the Seismic Performance of Steel Plate Shear Walls

    Get PDF
    ABSTRACT: The seismic performance demands of steel plate shear wall (SPSW) are estimated through the conventional pushover procedures. Reliability of the pushover analysis is verified through nonlinear time history analysis (NTHAs) on 9-, 6-and 3-story SPSW frames subjected to seven scaled earthquake records according to ASCE/SEI 7-05 provisions. Story drifts, displacements and story shears are the main parameters studied. A relatively accurate estimation is observed by pushover procedures compared to NTHAs. The accuracy of estimation shows an increase with respect to the height

    Interval prediction algorithm and optimal scenario making model for wind power producers bidding strategy

    Get PDF
    Nowadays, renewable energies are important sources for supplying electric power demand and a key entity of future energy markets. Therefore, wind power producers (WPPs) in most of the power systems in the world have a key role. On the other hand, the wind speed uncertainty makes WPPs deferent power generators, which in turn causes adequate bidding strategies, that leads to market rules, and the functional abilities of the turbines to penetrate the market. In this paper, a new bidding strategy has been proposed based on optimal scenario making for WPPs in a competitive power market. As known, the WPP generation is uncertain, and different scenarios must be created for wind power production. Therefore, a prediction intervals method has been improved in making scenarios and increase the accuracy of the presence of WPPs in the balancing market. Besides, a new optimization algorithm has been proposed called the grasshopper optimization algorithm to simulate the optimal bidding problem of WPPs. A set of numerical examples, as well as a case-study based on real-world data, allows illustrating and discussing the properties of the proposed method

    Eavaluation of antinociceptic effect of nano-emulsion gel conataining rosemary and peppermint essential oils in a rat model of osteoarthritis

    Get PDF
    Background and Aim: Despite identification of the antinociceptive effects of rosemary and peppermint essential oils, use of these essential oils has been limited due to its low solubility in water and low bioavailability. Use of nanoparticles is one of the ways to overcome these limitations. The aim of this study was to evaluate the antinociceptive effect of nano-emulsions containing rosemary and peppermint essential oils in an animal model of osteoarthritis (OA). Materials and Methods: In this experimental study nano-emulsions containing rosemary and peppermint essential oils were prepared by spontaneous emulsification. In order to investigate the analgesic effect, 30 male rats were randomly assigned to 5 groups: sham (receiving saline injection into the knee), osteoarthritis(receiving intra-articular injection of 2 mg monosodiumiodoacetate), OA (receiving gels containing nano-emulsion, or rosemary and peppermint essential oil or diclofenac sodium). Treatments were administered topically at a dose of 1 ml daily. Mechanical and thermal allodynia and thermal hyperalgesia tests were performed on the 1 st , 4 th , 7 th and 14 th days after injection. Data were analyzed by repeated measures ANOVA. Results: OA group showed a significant increased behavioral response to the mechanical and thermal stimuli on all days of the experiment compared to the control group (P<0.001). Use of nano-emulsion or diclofenac gel led to significant increase in the response threshold to von-Frey fillamets (P<0.001), decreased response to acetone (P<0.05), and increased paw withdrawal latency (P<0.05). Histopathology of knee tissues confirmed the results of behavioral tests. Conclusion: Nano-emulsion containing essential oils of rosemary and peppermint reduced pain of osteoarthritis in rats. The nano-emulsification process seems to enhance the antinociceptive effect of rosemary and peppermint essential oils. © 2018, Kurdistan University of Medical Sciences. All rights reserved

    The effect of cumin cyminum l. Plus lime administration onweight loss and metabolic status in overweight subjects: A randomized double-blind placebo-controlled clinical trial

    Get PDF
    Background: Limited data are available regarding the effects of combined administration of Cumin cyminum L. and lime on weight loss and metabolic profiles among subjects with overweight subjects. Objectives: The current study aimed to assess the effects of combined administration of Cumin cyminum L. and lime on weight loss and metabolic profiles among subjects with overweight. Patients and Methods: This randomized double-blind placebo-controlled clinical trial was conducted on 72 subjects with overweight, aged 18 - 50 years old. Participants were randomly divided into three groups: Group A received high-dose Cumin cyminum L. and lime capsules (75 mg each, n = 24), group B low-dose Cumin cyminum L. and lime capsules (25 mg each, n = 24) and group C placebos (n = 24) twice daily for eight weeks. Results: After eightweeksof intervention, comparedwithlow-dose C.cyminumL. plus limeandplacebo, taking high-dose C.cyminum L. plus lime resulted in significant weight loss (in the high-dose group: -2.1±1.7 vs. in the low-dose group: -1.2±1.5 and in the placebo group: + 0.2 ± 1.3 kg, respectively; P < 0.001) and body mass index (-0.8 ± 0.6 vs. -0.5 ± 0.5 and +0.1 ± 0.5 kg/m2, respectively; P < 0.001). In addition, administration of high-dose C. cyminum L. plus limecomparedwith low-dose C. cyminum L. plus limeandplacebo, led to a significant reduction in fasting plasma glucose (FPG) (P < 0.001) and a significant rise in quantitative insulin sensitivity check index (QUICKI) (+ 0.02 ± 0.02 vs. + 0.01 ± 0.02 and 0.01 ± 0.01, respectively; P = 0.01). Moreover, a significant decrease in serum triglycerides (-14.1 ± 56.2 vs. +13.9 ± 36.8 and + 10.6 ± 25.1 mg/dL; respectively; P = 0.03), total-cholesterol (-18.4 ± 28.6 vs. +8.6±28.5 and -1.0±24.8 mg/dL; respectively; P = 0.004) and low density lipoproteins-(LDL)-cholesterol levels (-11.8±20.7 vs. +6.5 ±23.2 and -2.9±20.4 mg/dL, respectively; P = 0.01) was observed following the consumption of high-dose C. cyminum L. plus lime compared with low-dose C. cyminum L. plus lime and placebo. Conclusions: Results of the current study indicated that taking high-dose C. cyminum L. plus lime for eight weeks among subjects with overweight had beneficial effects on weight, BMI, FPG, QUICKI, triglycerides, total-cholesterol and LDL-cholesterol levels. © 2016, Iranian Red Crescent Medical Journal

    Retinal findings of COVID-19 patients using ocular coherence tomography angiography two to three months after infection: Ocular appearance recovered COVID-19 patient

    Get PDF
    Purpose: The aim of this study was to evaluate the ocular disorders in COVID-19 patients, two to three months after infection. Methods: In this cross-sectional, historically controlled study, fifty-one COVID-19 patients were compared with thirty-seven age, and gender-matched healthy individuals. After complete ophthalmological examination, all participants underwent peripapillary and macular optical coherence tomography, and optical coherence tomography angiography (OCTA) measurements (OptoVue Inc, Freemont, CA, USA). Results: The time between the initial onset of symptoms, and ophthalmologic examination was 63.31±15.21 (40�95 days). Ophthalmic examination of all the recovered COVID-19 patients was within normal range. None of the peripapillary and macular OCTA parameters were significantly different between the two groups with pairwise comparisons, but after adjusting for age, gender, axial length, and signal strength index (SSI), recovered COVID-19 eyes showed a significant increase in peripapillary retinal nerve fiber (RNFL) thickness, superficial, and deep macular vessel densities in parafoveal and perifoveal regions compared with healthy control eyes (p<= 0.05). Inner retinal thickness overall is higher in recovered COVID-19 eyes compared to healthy eyes after adjustment. Conclusion: Patients with moderate-intensity SARS-CoV-2 pneumonia had altered peripapillary and macular vessel density compared to healthy subjects. Further investigation is warranted to analyze the correlation of these changes with disease severity as well as evolution of these changes over time

    O-C Study of 545 Lunar Occultations from 13 Double Stars

    Get PDF
    International audienceIn this article, we have studied the reports of lunar occultations by this project observation's teams (named APTO) in comparison with other observations of the objects. Thirteen binary stars were selected for this study. All the previous observations of these stars were also collected. Finally, an analysis of O-C of all reports were performed

    Accumulation and transport of microbial-size particles in a pressure protected model burn unit: CFD simulations and experimental evidence

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Controlling airborne contamination is of major importance in burn units because of the high susceptibility of burned patients to infections and the unique environmental conditions that can accentuate the infection risk. In particular the required elevated temperatures in the patient room can create thermal convection flows which can transport airborne contaminates throughout the unit. In order to estimate this risk and optimize the design of an intensive care room intended to host severely burned patients, we have relied on a computational fluid dynamic methodology (CFD).</p> <p>Methods</p> <p>The study was carried out in 4 steps: i) patient room design, ii) CFD simulations of patient room design to model air flows throughout the patient room, adjacent anterooms and the corridor, iii) construction of a prototype room and subsequent experimental studies to characterize its performance iv) qualitative comparison of the tendencies between CFD prediction and experimental results. The Electricité De France (EDF) open-source software <it>Code_Saturne</it><sup>® </sup>(<url>http://www.code-saturne.org</url>) was used and CFD simulations were conducted with an hexahedral mesh containing about 300 000 computational cells. The computational domain included the treatment room and two anterooms including equipment, staff and patient. Experiments with inert aerosol particles followed by time-resolved particle counting were conducted in the prototype room for comparison with the CFD observations.</p> <p>Results</p> <p>We found that thermal convection can create contaminated zones near the ceiling of the room, which can subsequently lead to contaminate transfer in adjacent rooms. Experimental confirmation of these phenomena agreed well with CFD predictions and showed that particles greater than one micron (i.e. bacterial or fungal spore sizes) can be influenced by these thermally induced flows. When the temperature difference between rooms was 7°C, a significant contamination transfer was observed to enter into the positive pressure room when the access door was opened, while 2°C had little effect. Based on these findings the constructed burn unit was outfitted with supplemental air exhaust ducts over the doors to compensate for the thermal convective flows.</p> <p>Conclusions</p> <p>CFD simulations proved to be a particularly useful tool for the design and optimization of a burn unit treatment room. Our results, which have been confirmed qualitatively by experimental investigation, stressed that airborne transfer of microbial size particles via thermal convection flows are able to bypass the protective overpressure in the patient room, which can represent a potential risk of cross contamination between rooms in protected environments.</p

    Housing mice in the individually ventilated or open cages—Does it matter for behavioral phenotype?

    Get PDF
    Individually ventilated caging (IVC) systems for rodents are increasingly common in laboratory animal facilities. However, the impact of such substantial change in housing conditions on animal physiology and behavior is still debated. Most importantly, there arise the questions regarding reproducibility and comparison of previous or new phenotypes between the IVC and open cages. The present study was set up for detailed and systematic comparison of behavioral phenotypes in male and female mice of three widely used inbred strains (C57BL/6JRccHsd, DBA/2JRccHsd, 129S2/SvHSd) after being kept in two housing environments (IVC and open cages) for 6?weeks (since 4?weeks of age) before behavioral testing. The tests addressed exploratory, anxiety-like and stress-related behavior (light-dark box, open field, forced swim test, stress-induced hyperthermia), social approach and species-specific behavior (nest building, marble burying). In all tests, large and expected strain differences were found. Somewhat surprisingly, the most striking effect of environment was found for basal body temperature and weight loss after one night of single housing in respective cages. In addition, the performance in light-dark box and open field was affected by environment. Several parameters in different tests showed significant interaction between housing and genetic background. In summary, the IVC housing did not invalidate the well-known differences between the mouse strains which have been established by previous studies. However, within the strains the results can be influenced by sex and housing system depending on the behavioral tasks applied. The bottom-line is that the environmental conditions should be described explicitly in all publications.Peer reviewe
    corecore