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Raman Scattered Ne VII$λ$973 at 4881 ? in the Symbiotic Star V1016 Cygni  [PDF]
Hee-Won Lee,Jeong-Eun Heo,Byeong-Cheol Lee
Physics , 2014, DOI: 10.1093/mnras/stu968
Abstract: We present the high resolution spectra of the symbiotic star V1016 Cygni obtained with the Bohyunsan Optical Echelle Spectrograph in 2003 and 2005, from which we find a broad emission feature at 4881 \AA. We propose that this broad feature is formed from Raman scattering of Ne VII$\lambda973$ by atomic hydrogen. Thus far, the detection of Raman scattered lines by atomic hydrogen is limited to O VI$\lambda\lambda$1032, 1038 and He II$\lambda\lambda$940, 972 and 1025. With the adoption of the center wavelength 973.302 \AA\ of Ne VII$\lambda$973 and consideration of the air refractive index of $n_{air}=1.000279348$, the atomic line center of the Raman scattered Ne VII feature is determined to be 4880.53 \AA. The total cross section at the line center of Ne VII$\lambda973$ is computed to be $2.62\times 10^{-22}{\rm\ cm^2}$ with the branching ratio of 0.17. We perform Monte Carlo simulations to fit the Raman scattered Ne VII$\lambda973$. Assuming that the Ne VII and He II emission regions share the same kinematics with respect to the neutral scattering region, we find that the Raman scattered He II$\lambda$972 at 4850 \AA\ and Ne VII$\lambda$973 at 4881 \AA\ are excellently fitted. We also propose that the He II and Ne VII emission regions were stationary with respect to the H I region in 2003 but that they were receding from it with a velocity $\sim 20{\rm\ km\ s^{-1}}$ in 2005.
Donaldson theory on non-K?hlerian surfaces and class $VII$ surfaces with $b_2=1$  [PDF]
Andrei Teleman
Mathematics , 2007,
Abstract: We prove that any class $VII$ surface with $b_2=1$ has curves. This implies the "Global Spherical Shell conjecture" in the case $b_2=1$: Any minimal class $VII$ surface with $b_2=1$ admits a global spherical shell, hence it is isomorphic to one of the surfaces in the known list. The main idea of the proof is to show that a certain moduli space of PU(2)-instantons on a surface $X$ with no curves (if such a surface existed) would contain a closed Riemann surface $Y$ whose general points correspond to non-filtrable holomorphic bundles on $X$. Then we pass from a family of bundles on $X$ parameterized by $Y$ to a family of bundles on $Y$ parameterized by $X$, and we use the algebraicity of $Y$ to obtain a contradiction. The proof uses essentially techniques from Donaldson theory: compactness theorems for moduli spaces of PU(2)-instantons and the Kobayashi-Hitchin correspondence on surfaces.
Prevalence of collagen VII-specific autoantibodies in patients with autoimmune and inflammatory diseases
Emilia Licarete, Susanne Ganz, Martin J Recknagel, Giovanni Di Zenzo, Takashi Hashimoto, Michael Hertl, Giovanna Zambruno, Gheorghe Hundorfean, Jonas Mudter, Markus F Neurath, Leena Bruckner-Tuderman, Cassian Sitaru
BMC Immunology , 2012, DOI: 10.1186/1471-2172-13-16
Abstract: Based on in silico antigenic analysis and previous wetlab epitope mapping data, we designed a chimeric collagen VII construct containing all collagen VII epitopes with higher antigenicity. ELISA was performed with sera from patients with EBA (n = 50), Crohn's disease (CD, n = 50), ulcerative colitis (UC, n = 50), bullous pemphigoid (BP, n = 76), and pemphigus vulgaris (PV, n = 42) and healthy donors (n = 245).By ELISA, the receiver operating characteristics analysis yielded an area under the curve of 0.98 (95% CI: 0.9638-1.005), allowing to set the cut-off at 0.32 OD at a calculated specificity of 98% and a sensitivity of 94%. Running the optimized test showed that serum IgG autoantibodies from 47 EBA (94%; 95% CI: 87.41%-100%), 2 CD (4%; 95% CI: 0%-9.43%), 8 UC (16%; 95% CI: 5.8%-26%), 2 BP (2.63%; 95% CI: 0%-6.23%), and 4 PV (9.52%; 95% CI: 0%-18.4%) patients as well as from 4 (1.63%; 95% CI: 0%-3.21%) healthy donors reacted with the chimeric protein. Further analysis revealed that in 34%, 37%, 16% and 100% of sera autoantibodies of IgG1, IgG2, IgG3, and IgG4 isotype, respectively, recognized the recombinant autoantigen.Using a chimeric protein, we developed a new sensitive and specific ELISA to detect collagen specific antibodies. Our results show a low prevalence of collagen VII-specific autoantibodies in inflammatory bowel disease, pemphigus and bullous pemphigoid. Furthermore, we show that the autoimmune response against collagen VII is dominated by IgG4 autoantibodies. The new immunoassay should prove a useful tool for clinical and translational research and should improve the routine diagnosis and disease monitoring in diseases associated with collagen VII-specific autoimmunity.An immune response against collagen VII is typically associated with epidermolysis bullosa acquisita (EBA) and bullous systemic lupus erythematosus, but may occur in other conditions, including inflammatory bowel disease (IBD) and dystrophic epidermolysis bullosa [1,2]. EBA is an acqu
Revealing O VII from stacked X-ray grating spectra of clusters, groups and elliptical galaxies  [PDF]
J. S. Sanders,A. C. Fabian
Physics , 2010, DOI: 10.1111/j.1745-3933.2010.01000.x
Abstract: We stack 4.6 Ms of high spectral resolution XMM-Newton Reflection Grating Spectrometer spectra from galaxy clusters, groups of galaxies and elliptical galaxies. For those objects with a central temperature of less than 1 keV, we detect O VII for the first time, with a probability of false detection of 2.5x10^-4. The flux ratio of the O VII to Fe XVII lines is 1/4 to 1/8 of the emission expected for isobaric radiative cooling in the absence of heating. There is either a process preventing cooling below 0.5 keV, anomalous O/Fe abundance ratios, absorbing material around the coolest X-ray emitting gas or non-radiative cooling taking place. The mean N VII emission line is strong in the sub-keV sample. As the ratio of the hydrogenic N and O lines is largely independent of temperature, we measure a mean N/O ratio of 4.0 +- 0.6 Solar. Although the continuum around the C VI lines is difficult to measure we can similarly estimate that the C/O ratio is 0.9 +- 0.3 Solar.
A Stellar Population Gradient in VII Zw 403 - Implications for the Formation of Blue Compact Dwarf Galaxies  [PDF]
Regina E. Schulte-Ladbeck,Ulrich Hopp,Mary M. Crone,Laura Greggio
Physics , 1999, DOI: 10.1086/307950
Abstract: We present evidence for the existence of an old stellar halo in the Blue Compact Dwarf galaxy VII Zw 403. VII Zw 403 is the first Blue Compact Dwarf galaxy for which a clear spatial segregation of the resolved stellar content into a "core-halo" structure is detected. Multicolor HST/WFPC2 observations indicate that active star formation occurs in the central region, but is strikingly absent at large radii. Instead, a globular-cluster-like red giant branch suggests the presence of an old (> 10 Gyr) and metal poor (<[Fe/H]>=-1.92) stellar population in the halo. While the vast majority of Blue Compact Dwarf galaxies has been recognized to possess halos of red color in ground-based surface photometry, our observations of VII Zw 403 establish for the first time a direct correspondence between a red halo color and the presence of old, red giant stars. If the halos of Blue Compact Dwarf galaxies are all home to such ancient stellar populations, then the fossil record conflicts with delayed-formation scenarios for dwarfs.
Instantons and curves on class VII surfaces  [PDF]
Andrei Teleman
Mathematics , 2007,
Abstract: We develop a general strategy, based on gauge theoretical methods, to prove existence of curves on class VII surfaces. We prove that, for $b_2=2$, every minimal class VII surface has a cycle of rational curves hence, by a result of Nakamura, is a global deformation of a one parameter family of blown up primary Hopf surfaces. The case $b_2=1$ has been solved in a previous article. The fundamental object intervening in our strategy is the moduli space ${\mathcal M}^{\pst}(0,{\mathcal K})$ of polystable bundles ${\mathcal E}$ with $c_2({\mathcal E})=0$, $\det({\mathcal E})={\mathcal K}$. For large $b_2$ the geometry of this moduli space becomes very complicated. The case $b_2=2$ treated here in detail requires new ideas and difficult techniques of both complex geometric and gauge theoretical nature.
立方氧化锆压腔下冰VI-VII相变的Raman散射光谱研究
孙樯,郑海飞,陈晋阳
自然科学进展 , 2002,
Abstract: 295K和1.1~3.3GPa条件下,通过冰VI-VII的OH伸缩振动Raman光谱分析,对压力与冰VI-VII结构的关系进行了研究.可以看出:(i)在1.1~1.7GPa范围内,OH的伸缩振动频率随压力升高而降低,d v 1 /d p=-66.66cm -1 ·GPa -1 ;(ii)压力为2.1GPa时,OH的伸缩振动明显向高频方向移动;(iii)随着压力进一步增大(2.1~3.3GPa),OH的伸缩振动再次向低频方向移动,d v 1 /d p=-22.5cm -1 ·GPa -1 .这是由于压力升高导致d OH 增大造成的;而压力为2.1GPa时,OH的伸缩振动频率的突变则是冰VI-VII相变的结果.此外,根据冰VII的X衍射数据,发现d OO 与压力存在以下经验公式:d OO =0.0014P 2 -0.042P+3.0028.
Blood flow controls coagulation onset via the positive feedback of factor VII activation by factor Xa
Alexey M Shibeko, Ekaterina S Lobanova, Mikhail A Panteleev, Fazoil I Ataullakhanov
BMC Systems Biology , 2010, DOI: 10.1186/1752-0509-4-5
Abstract: Using a detailed mechanism-driven model of tissue factor (TF)-initiated thrombus formation in a two-dimensional channel we demonstrate that blood flow can regulate clotting onset in the model in a threshold-like manner, in agreement with existing experimental evidence. Sensitivity analysis reveals that this is achieved due to a combination of the positive feedback of TF-bound factor VII activation by activated factor X (Xa) and effective removal of factor Xa by flow from the activating patch depriving the feedback of "ignition". The level of this trigger (i.e. coagulation sensitivity to flow) is controlled by the activity of tissue factor pathway inhibitor.This mechanism explains the difference between red and white thrombi observed in vivo at different shear rates. It can be speculated that this is a special switch protecting vascular system from uncontrolled formation and spreading of active coagulation factors in vessels with rapidly flowing blood.Blood coagulation is a complex reaction network that functions to form a fibrin clot that covers damaged vessel wall and prevents blood loss [1]. The clotting process is initiated by tissue factor (TF), a transmembrane protein exposed in the damaged parts of the wall. This protein forms a complex called extrinsic tenase with plasma protein activated factor VII (VIIa). Extrinsic tenase activates factor X, which activates thrombin, the main protein of blood coagulation. Activated factor X (factor Xa) activates factor VII in complex VII-TF (inactive extrinsic tenase), thus forming a positive feedback. Extrinsic tenase is inhibited by tissue factor pathway inhibitor (TFPI) in a complex factor Xa-dependent manner [2]. Thrombin forms fibrin, which polymerizes to create a clot.Although reactions of the coagulation cascade are well known, and no new essential components of this system have been discovered over the last fifteen years [1], the present understanding of the functioning of this system is limited. The incredible bioc
Moduli Spaces of PU(2)-Instantons on Minimal Class VII Surfaces with b_2=1  [PDF]
Konrad Sch?bel
Mathematics , 2007, DOI: 10.5802/aif.2395
Abstract: We describe explicitly the moduli spaces $M^{pst}_g(S,E)$ of polystable holomorphic structures $E$ with $\det E\cong K$ on a rank 2 vector bundle $E$ with $c_1(E)=c_1(K)$ and $c_2(E)=0$ for all minimal class VII surfaces $S$ with $b_2(S)=1$ and with respect to all possible Gauduchon metrics $g$. These surfaces $S$ are non-elliptic and non-Kaehler complex surfaces and have recently been completely classified. When $S$ is a half or parabolic Inoue surface, $M^{pst}_g(S,E)$ is always a compact one-dimensional complex disc. When $S$ is an Enoki surface, one obtains a complex disc with finitely many transverse self-intersections whose number becomes arbitrarily large when $g$ varies in the space of Gauduchon metrics. $M^{pst}_g(S,E)$ can be identified with a moduli space of PU(2)-instantons. The moduli spaces of simple bundles of the above type leads to interesting examples of non-Hausdorff singular one-dimensional complex spaces.
Uncertainty Analyses Applied to the UAM/TMI-1 Lattice Calculations Using the DRAGON (Version 4.05) Code and Based on JENDL-4 and ENDF/B-VII.1 Covariance Data  [PDF]
Augusto Hernández-Solís,Christophe Demazière,Christian Ekberg
Science and Technology of Nuclear Installations , 2013, DOI: 10.1155/2013/437854
Abstract: The OECD/NEA Uncertainty Analysis in Modeling (UAM) expert group organized and launched the UAM benchmark. Its main objective is to perform uncertainty analysis in light water reactor (LWR) predictions at all modeling stages. In this paper, multigroup microscopic cross-sectional uncertainties are propagated through the DRAGON (version 4.05) lattice code in order to perform uncertainty analysis on and 2-group homogenized macroscopic cross-sections. The chosen test case corresponds to the Three Mile Island-1 (TMI-1) lattice, which is a 15 15 pressurized water reactor (PWR) fuel assembly segment with poison and at full power conditions. A statistical methodology is employed for the uncertainty assessment, where cross-sections of certain isotopes of various elements belonging to the 172-group DRAGLIB library format are considered as normal random variables. Two libraries were created for such purposes, one based on JENDL-4 data and the other one based on the recently released ENDF/B-VII.1 data. Therefore, multigroup uncertainties based on both nuclear data libraries needed to be computed for the different isotopic reactions by means of ERRORJ. The uncertainty assessment performed on and macroscopic cross-sections, that is based on JENDL-4 data, was much higher than the assessment based on ENDF/B-VII.1 data. It was found that the computed Uranium 235 fission covariance matrix based on JENDL-4 is much larger at the thermal and resonant regions than, for instance, the covariance matrix based on ENDF/B-VII.1 data. This can be the main cause of significant discrepancies between different uncertainty assessments. 1. Introduction The significant increase in capacity of new computational technology made it possible to switch to a newer generation of complex codes, which are capable of representing the feedback between core thermal-hydraulics and neutron kinetics in detail. The coupling of advanced, best estimate (BE) models is recognized as an efficient method of addressing the multidisciplinary nature of reactor accidents with complex interfaces between disciplines. However, code predictions are uncertain due to several sources of uncertainty, like code models as well as uncertainties of plant, materials, and fuel parameters. Therefore, it is necessary to investigate the uncertainty of the results if useful conclusions are to be obtained from BE codes. In the current procedure for light water reactor analysis, during the first stage of the neutronic calculations, the so-called lattice code is used to calculate the neutron flux distribution over a specified region
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