Study of Central Intensity Ratio of Seyfert Galaxies in Nearby Universe

We use the recently discovered simple photometric parameter Central Intensity Ratio(CIR)determined for a sample of 57 nearby(z<0.02)Seyfert galaxies to explore the central features of galaxies and their possible connection with galaxy evolution.The sample of galaxies shows strong anti-correlation between CIR and mass of their central supermassive black holes(SMBHs).The SMBH masses of ellipticals are systematically higher for a given CIR value than those for lenticulars and spirals in the sample.However,the correlation between CIR and central velocity dispersion is weak.CIR appears less influenced by the excess flux produced by the central engine in these galaxies,when compared to spectroscopic parameters like velocity dispersion and OⅣflux,and proves to be a fast and reliable tool for estimating central SMBH mass.

光老化成纤维细胞分泌的细胞外基质对HaCaT细胞增殖的影响

目的:评价紫外线诱导衰老成纤维细胞分泌的细胞外基质对HaCaT细胞增殖的促进作用。方法:连续UVB辐射诱导成纤维细胞发生应激性衰老(SIPS)。成纤维细胞接种后,制备细胞外基质(ECM)。将预处理的HaCaT细胞接种到包被ECM的平皿。流式细胞仪检测HaCaT细胞周期和凋亡,MTT法检测细胞的增殖。结果:UVB-SIPS成纤维细胞分泌的ECM对HaCaT细胞具有较强的促增殖作用,但对细胞凋亡无显著影响。结论:UVB-SIPS成纤维细胞分泌的ECM可以更强地促进HaCaT细胞的增殖。

中波紫外线和氧化应激诱导LECs中Ⅰ型胶原降解的分子机制研究

目的探讨中波紫外线(UVB)和氧化应激诱导人晶状体上皮细胞(LECs)中Ⅰ型胶原降解的时间和剂量依赖方式及其作用信号通路。方法培养人LECs,用UVB(15mJ/cm2)或H2O2(100μmol/L)分别处理细胞,Western blot法检测不同时间段的Ⅰ型胶原表达和JNK、c-Jun的磷酸化,Glatin酶谱法分析不同时间段的间质胶原酶(MMP-1)表达,且用不同剂量的UVB辐射或不同浓度H2O2作用后检测上述指标。结果在用UVB和H2O2处理后,Ⅰ型胶原的表达明显下降,8h后为0.890,24h后为0.779。UVB和H2O2以时间和剂量依赖的方式诱导JNK-1和c-Jun的磷酸化,MMP-1的表达也以时间依赖的方式增加。结论在人工培养的人LECs中,UVB、H2O2通过时间和剂量的方式诱导JNK和c-Jun的磷酸化,导致MMP-1和Ⅰ型胶原表达,这一作用通路可能形成潜在的治疗后发性白内障的靶点。

Mooring System Optimisation and Effect of Different Line Design Variables on Motions of Truss Spar Platforms in Intact and Damaged Conditions

This paper presents the effect of mooring diameters, fairlead slopes and pretensions on the dynamic responses of a truss spar platform in intact and damaged line conditions. The platform is modelled as a rigid body with three degrees-of-freedom and its motions are analysed in time-domain using the implicit Newmark Beta technique. The mooring restoring force-excursion relationship is evaluated using quasi-static approach. MATLAB codes DATSpar and QSAML, are developed to compute the dynamic responses of truss spar platform and to determine the mooring system stiffness. To eliminate the conventional trial and error approach in the mooring system design, a numerical tool is also developed and described in this paper for optimising the mooring configuration. It has a graphical user interface and includes regrouping particle swarm optimisation technique combined with DATSpar and QSAML. A case study of truss spar platform with ten mooring lines is analysed using this numerical tool. The results show that optimum mooring system design benefits the oil and gas industry to economise the project cost in terms of material, weight, structural load onto the platform as well as manpower requirements. This tool is useful especially for the preliminary design of truss spar platforms and its mooring system.

Condition Assessment Techniques for Aged Fixed-Type Offshore Platforms Considering Decommissioning:a Historical Review

In this study,the technical papers on structural condition assessment of aged fixed-type offshore platforms reported over the past few decades are presented.Other ancillary related works are also discussed.Large numbers of researches are available in the area of requalification for life extension of offshore jacket platforms.Many of these studies involve reassessment of existing platforms by means of conducting pushover analysis,a static nonlinear collapse analysis method to evaluate the structure nonlinear behaviour and capacity beyond the elastic limit.From here,the failure mechanism and inherent reserve strength/capacity of the overall truss structure are determined.This method of doing reassessment is described clearly in the industry-adopted codes and standards such the API,ISO,PTS and NORSOK codes.This may help understand the structural behaviour of aged fixed offshore jacket structures for maintenance or decommissioning.

Long term optical variability of bright X-ray point sources in elliptical galaxies

We present long term optical variability studies of bright X-ray sources in four nearby elliptical galaxies with the Chandra Advanced CCD Imaging Spectrometer array （ACIS-S） and observations from the Hubble Space Telescope （HST） Advanced Camera for Surveys. Out of the 46 bright （X-ray counts 〉 60） sources that are in the common field of view of the Chandra and HST observations, 34 of them have potential optical counterparts, while the rest of them are optically dark. After taking into account systematic errors, estimated using optical sources in the field as a reference, we find that four of the X-ray sources （three in NGC 1399 and one in NGC 1427） have variable optical counterparts at a high level of significance. The X-ray luminosities of these sources are ～10^38 erg S^-1 and are also variable on similar time scales. The optical variability implies that the optical emission is asso- ciated with the X-ray source itself rather than being the integrated light from a host globular cluster. For one source, the change in optical magnitude is 〉 0.3, which is one of the highest reported for this class of X-ray sources and this suggests that the optical variability is induced by the X-ray activity. However, the optically variable sources in NGC 1399 have been reported to have blue colors （g - z 〉 1）. All four sources have been detected in the infrared （IR） by Spitzer as point sources, and their ratios of 5.8 to 3.6 μm flux are 〉 0.63, indicating that their IR spectra are like those of Active Galactic Nuclei （AGNs）. While spectroscopic confirmation is required, it is likely that all four sources are background AGNs. We find none of the X-ray sources having opticalfiR colors different from AGNs to be optically variable.

Optimal Price Strategy under Price-Matching Policy

The paper explores the optimal price strategy under the price-matching policy. First, the paper formulates the demand function under the price match policy and then discovers the retailer’s best response facing the price-matching pressure. From the theoretical analysis, we discover how the number of retailers plays an important role during the competition. When only two retailers are involved, the final prices may not converge to a single value. However, when more retailers are involved, the final price will converge to a single value. We also use numerical studies to illuminate the change of the prices over the time period, the sensitivity of the final price to the increment/decrement of initial prices. Finally, we provide managerial suggestions to both producers and retailers.

UVB应激性衰老成纤维细胞分泌细胞外基质对HaCaT细胞ERK信号的影响

目的探讨UVB诱导的衰老（UVB—SIPS）成纤维细胞分泌的细胞外基质（ECM）对HaCaT细胞增殖的影响以及细胞外信号调节激酶（ERK）信号途径的作用。方法采用辐射诱导人皮肤成纤维细胞衰老，分别制备由未衰老和衰老成纤维细胞分泌的ECM包被的培养皿（分别定为PRE—ECM组、SCIP—ECM组）。以空白培养皿（NON—ECM组）为参照，在HaCaT细胞接种于培养皿后，采用MTF法和流式细胞法检测其细胞增殖、细胞周期等指标的变化；免疫印迹法分析ERK活化水平。干预性研究ERK信号通路对上述功能的影响。结果三组中，SCIP—ECM组可诱导最强烈的ERK1／2的活化。采用U0126抑制ERK信号活化可完全抑制衰老成纤维细胞来源的ECM的促细胞增殖效应。阻断HaCaT细胞的ERK活化，NON—ECM组、PRE—ECM组和SCIP—ECM组S＋G2／M期细胞的比例明显下降，分别由处理前37．40％、41．34％和43．31％减少至29．41％、36．48％到39．96％。结论UVB—SCIP成纤维细胞分泌的ECM通过刺激ERK磷酸化促进HaCaT细胞增殖。

Effects of space and temperature dependent internal heat generation/absorption on MHD flow of a nanofluid over a stretching sheet

In this paper we analyzed the effects of space and temperature dependent intemal heat generation/absorption （non-uniform heat source/sink） on magnetohydrodynamic boundary layer flow of water based nanofluid over a stretching sheet with different nanoparticles. The flow is generated due to linear stretching of the sheet and influenced by uniform magnetic field, which is applied normally to the stretching sheet. A scaling group of transformation is used to reduce the governing momentum and energy equations into non-linear ordinary differential equations. The resulting differential equations are solved analytically using hypergeometric functions and numerically by the fourth order Runge-Kutta method with shooting technique. The influence of nanoparticle volume fraction, magnetic field, Prandtl number, non uniform heat source/sink, local skin friction coefficient and reduced Nusselt number are investigated for different nanoparticles.

评邦格的《科学唯物主义》

M.邦格的《科学唯物主义》,一开始就承认哲学唯物主义似乎是虚弱无力和早已过时的了。邦格告诉读者,哲学唯物主义对生活、思想以及人类思想的创造物,如价值观、文化和数学,给予似乎合理解释的企图,已经起了窒息的作用。邦格的目的,是使哲学唯物主义按照当代的逻辑学、数学和科学的要求,重新获得新生并跟上现时代。邦格确信这个任务的重要性,因为他认为,唯物主义是唯一的科学和技术的本体论,而且对他来说,只有科学才能产生真正实在经验的知识。邦格希望,他的著作的价值是为当代科学提供一个适当的概念框架,能引导读者把唯物主义当作一个研究领域,而不是把唯物主义当作一个僵化的信仰体系。在构造他的科学和技术本体论过程中,邦格不仅注意到避免唯心主义者所犯的把时空概念具体化的错误,而且由于这些唯心主义者是他的“亲兄弟”(可以这么说)。

MHD flow of Boungiorno model nanofluid over a vertical plate with internal heat generation/absorption

A mathematical analysis has been carried out to investigate the effect of internal heat generation/absorption on steady two-dimensional radiative magnetohydrodynamics(MHD)boundary-layer flow of a viscous,incompressible nanofluid over a vertical plate.A system of governing nonlinear PDEs is converted into a set of nonlinear ODEs by suitable similarity transformations and then solved analytically using HAM and numerically by the fourth order Runge–Kutta integration scheme with shooting method.The effects of different controlling parameters on the dimensionless velocity,temperature and nanoparticle volume fraction profiles are discussed graphically.The reduced Nusslet number and the local Sherwood number are tabulated.It is found that the nanosolid volume fraction profile decreases in the presence of heat generation and increases in the case of heat absorption and a reverse trend is observed in velocity profile.An excellent agreement is observed between present analytical and numerical results.Furthermore,comparisons have been made with bench mark solutions for a special case and obtained a very good agreement.