253 research outputs found

    A Study of (

    Get PDF
    We deal with topics regarding (λ,μ)-fuzzy subgroups, mainly (λ,μ)-fuzzy cosets and (λ,μ)-fuzzy normal subgroups. We give basic properties of (λ,μ)-fuzzy subgroups and present some results related to (λ,μ)-fuzzy cosets and (λ,μ)-fuzzy normal subgroups

    Modelling the thickness of landfast sea ice in Prydz Bay, East Antarctica

    Get PDF
    Landfast sea ice forms and remains fixed along the coast for most of its life time. In Prydz Bay, landfast ice is seasonal due to melting, mechanical breakage and drift of ice in summer. Its annual cycle of thickness and temperature was examined using a one-dimensional thermodynamic model. Model calibration was made for March 2006 to March 2007 with forcing based on the Chinese National Antarctic Research Expedition data, which consisted of in situ ice and snow observations and meteorological records at the Zhongshan Station. The observed maximum annual ice thickness was 1.74 m. The ice broke and drifted out in summer when its thickness was 0.5-1.0 m. Oceanic heat flux was estimated by tuning the model with observed ice thickness. In the growth season, it decreased from 25 Wm(-2) to 5W m(-2), and in summer it recovered back to 25 W m(-2). Albedo was important in summer; by model tuning the estimated value was 0.6, consistent with the ice surface being bare all summer. Snow cover was thin, having a minor role. The results can be used to further our understanding of the importance of landfast ice in Antarctica for climate research and high-resolution ice-ocean modelling.Peer reviewe

    Concurrent administration of amiodarone and atenolol in the treatment of coronary artery disease complicated with arrhythmia, and its effect on serum levels of CD40L, TNF-α and IL-6

    Get PDF
    Purpose: To investigate the efficacy of the combination of amiodarone and atenolol in the treatment of patients with coronary artery disease (CAD) complicated with arrhythmia, and its effect on serum levels of CD-40L, TNF-α and IL-6.Methods: One hundred and twenty CAD patients with arrhythmia on admission in The First People'sHospital of Shuangliu District Chengdu, China were assigned to groups A and B, each having 60 patients. Amiodarone was administered to all the patients, while atenolol was additionally given to patients in group A. Levels of heart function indicators, inflammatory factors, blood pressure, heart rate, adverse reaction rate (ARR) and overall efficacy were evaluated for the two groups.Results: There were significantly improved levels of heart function indicators, and lower levels of CD40L, TNF-α and IL-6 in group A, when compared with group B (p < 0.001). Moreover, treatment effectiveness was higher in group A than in group B (p < 0.05). However, there was no significant difference (p > 0.05) in ARR between groups A and B.Conclusion: The combined use of amiodarone and atenolol improves heart function indicators in patients with CAD and arrhythmia, reduces the levels of inflammatory factors, normalizes blood pressure and heart rate, and lowers ARR. However, further clinical trials on this combined therapy are required prior to its use in clinical practice

    The implementation plan of e-learning to fulfill new demands of librarians’ continuing education in city library network building

    Get PDF
    The changing trends in a rapidly evolving information society ask the LIS education to play a more and more important role in directing LIS professional not only by providing renowned degree programs in LIS schools but also by leading advanced continuing education for librarians. Under the background of China’s public culture policies, GuangZhou started to build a public library services system named "Guangzhou City of Libraries" in 2015. The current situation of human resources is the key problem to be solved, specifically, the severe shortage of workforce, the professionalism disqualification, and the unsatisfactory continuing education (Zhang, et.al., 2019a). According to the status survey, the continuing education which is mostly provided by local library associations, cannot satisfy the needs which manifests in limited coverage of training themes and audiences (Zhang, et.al., 2018). This is a further study based on the data and results of the series of formal studies conducted by the authors. An implementation plan of librarians’ continuing education for "Guangzhou City of Libraries" in the next two years has been drafted with a part of a detailed plan using e-learning to help make the continuing education professional, systematic, thematic, long-term tendency and extensive and fulfill new demands. This e-learning part, together with the whole draft implementation plan, will be presented to an advisory group. Adopting questionnaire and interview as the methods, the opinion of the advisory group on the feasibility, availability, validity, authority and risk of using e-learning in continuing education for large number of librarians in "Guangzhou City of Libraries" will be collected and analyzed. The opinion on the implementation plan of e-learning to fulfill new demands of librarians’ continuing education will be summarized and discussed

    The Cytochrome bd Complex Is Essential for Chromate and Sulfide Resistance and Is Regulated by a GbsR-Type Regulator, CydE, in Alishewanella Sp. WH16-1

    Get PDF
    Sulfate-reducing bacteria are a group of microorganisms that use sulfate as an electron acceptor. These bacteria are useful in the bioremediation of heavy metal pollution since they can reduce/precipitate metals. Previously, we identified the Alishewanella strain WH16-1 from soil of a copper and iron mine and determined that it can reduce sulfate and chromate and that it was tolerant to many heavy metals. In this study, we investigated the chromate reduction mechanism of strain WH16-1 through Tn5 transposon mutagenesis. A cytochrome bd (cytbd) Tn5 mutant was generated (Δcytbd), and a detail analysis showed that the following: (1) gene cydE (coding for a GbsR-type regulator) was co-transcribed with the two subunits coding genes of the Cytochrome bd complex (Cytbd), namely, cydA and cydB, based on RT-PCR analysis, and similar gene arrangements were also found in other Alteromonadaceae family strains; (2) the chromate resistance level was dramatically decreased and chromate reduction efficiency also decreased in strain Δcytbd compared to the wild-type and a complemented strain (Δcytbd-C); (3) Cytbd could catalyze the decomposition of H2O2 according to the analyses of H2O2 decomposition ability, cellular H2O2 contents, H2O2 inhibition zone, and H2O2 sensitivity tests; (4) surprisingly, chromate was not an inducer of the expression of Cytbd, but sulfate induced expression of Cytbd, and sulfate/sulfide resistance levels were also decreased in the Δcytbd strain; (5) the addition of sulfate enhanced the chromate resistance level and reduction efficiency; (6) Cytbd expression was repressed by CydE and derepressed by sulfate based on an in vivo bacterial one hybrid system and in vitro EMSA tests; and (7) DNA footprinting and short-fragment EMSA tests revealed two binding sites of CydE in its promoter region. All these results showed that Cytbd is negatively regulated by CydE and derepressed by sulfate. In addition, Cytbd contributes to the resistance of sulfate and sulfide, and sulfide could be used as a reductant to reduce chromate. Moreover, Cytbd is essential to decompose H2O2 to decrease cellular oxidative stress. Thus, the regulation and function of Cytbd may explain why sulfate could enhance chromate reduction

    Thermal Diffusivity Identification of Distributed Parameter Systems to Sea Ice

    Get PDF
    A method of optimal control is presented as a numerical tool for solving the sea ice heat transfer problem governed by a parabolic partial differential equation. Taken the deviation between the calculated ice temperature and the measurements as the performance criterion, an optimal control model of distributed parameter systems with specific constraints of thermal properties of sea ice was proposed to determine the thermal diffusivity of sea ice. Based on sea ice physical processes, the parameterization of the thermal diffusivity was derived through field data. The simulation results illustrated that the identified parameterization of the thermal diffusivity is reasonably effective in sea ice thermodynamics. The direct relation between the thermal diffusivity of sea ice and ice porosity is physically significant and can considerably reduce the computational errors. The successful application of this method also explained that the optimal control model of distributed parameter systems in conjunction with the engineering background has great potential in dealing with practical problems

    Preliminary results on relationship between thermal diffusivity and porosity of sea ice in the Antarctic

    Get PDF
    The in situ sea - ice temperature, salinity and density observed from Chinese Antarctic Zhongshan Station have been applied to calculate the vertical profile of sea ice porosity. Based on numerical method, a number of schemes on sea - ice thermal diffusivity versus porosity have been accessed and one optimized scheme is identified by an optimal control model with an advanced distributing parameter system. For simplicity, the internal heating source item was neglected in the heat conduction equation during the identification procedure. In order to illustrate the applicability of this identified scheme, the vertical ice temperature profiles have been simulated and compared with measurements, respectively by using identified scheme and by classical thermodynamic formulae. The comparisons indicated that the scheme describing sea - ice thermal diffusivity and porosity is reasonable. In spite of a minor improvement of accuracy of results against in situ data, the identified scheme has a more physical meaning and could be used potentially in various applications
    corecore