Exclusive rho^0 muoproduction on transversely polarised protons and deuterons

The transverse target spin azimuthal asymmetry A_UT in hard exclusive production of rho^0 mesons was measured at COMPASS by scattering 160 GeV/c muons off transversely polarised protons and deuterons. The measured asymmetry is sensitive to the nucleon helicity-flip generalised parton distributions E^q, which are related to the orbital angular momentum of quarks in the nucleon. The Q^2, x_B and p_t^2 dependence of A_UT is presented in a wide kinematic range. Results for deuterons are obtained for the first time. The measured asymmetry is small in the whole kinematic range for both protons and deuterons, which is consistent with the theoretical interpretation that contributions from GPDs E^u and E^d approximately cancel.Comment: 20 pages, 9 figures and 4 tables, updated author lis

外汇风险溢酬理论述评

外汇风险溢酬是从资产定价角度研究汇率变化的核心内容,但还未获得一致结论。目前,对外汇风险溢酬的时间序列建模并不理想,隐含变量模型和仿射模型都不能刻画外汇风险溢酬的时间序列特征;对外汇风险溢酬风险因子的研究缺乏一个统一框架,消费、微观市场因子和货币政策都只能部分解释外汇风险溢酬的变化。基于随机贴现因子的模型目前相对零散,但这一框架是后续研究的重点。一个亟待研究的课题是既把汇率作为投资性资产的价格,又考虑汇率作为两国货币的相对比价,研究外汇风险溢酬与两国经济波动、两国经济相关性的内在联系,从理论上厘清影响外汇风险溢酬的因素

phenix.mr_rosetta: molecular replacement and model rebuilding with Phenix and Rosetta.

The combination of algorithms from the structure-modeling field with those of crystallographic structure determination can broaden the range of templates that are useful for structure determination by the method of molecular replacement. Automated tools in phenix.mr_rosetta simplify the application of these combined approaches by integrating Phenix crystallographic algorithms and Rosetta structure-modeling algorithms and by systematically generating and evaluating models with a combination of these methods. The phenix.mr_rosetta algorithms can be used to automatically determine challenging structures. The approaches used in phenix.mr_rosetta are described along with examples that show roles that structure-modeling can play in molecular replacement

The Presence of the Iron-Sulfur Motif Is Important for the Conformational Stability of the Antiviral Protein, Viperin

Viperin, an antiviral protein, has been shown to contain a CX3CX2C motif, which is conserved in the radical S-adenosyl-methionine (SAM) enzyme family. A triple mutant which replaces these three cysteines with alanines has been shown to have severe deficiency in antiviral activity. Since the crystal structure of Viperin is not available, we have used a combination of computational methods including multi-template homology modeling and molecular dynamics simulation to develop a low-resolution predicted structure. The results show that Viperin is an α -β protein containing iron-sulfur cluster at the center pocket. The calculations suggest that the removal of iron-sulfur cluster would lead to collapse of the protein tertiary structure. To verify these predictions, we have prepared, expressed and purified four mutant proteins. In three mutants individual cysteine residues were replaced by alanine residues while in the fourth all the cysteines were replaced by alanines. Conformational analyses using circular dichroism and steady state fluorescence spectroscopy indicate that the mutant proteins are partially unfolded, conformationally unstable and aggregation prone. The lack of conformational stability of the mutant proteins may have direct relevance to the absence of their antiviral activity

Mutations in the histone methyltransferase gene KMT2B cause complex early-onset dystonia.

Histone lysine methylation, mediated by mixed-lineage leukemia (MLL) proteins, is now known to be critical in the regulation of gene expression, genomic stability, cell cycle and nuclear architecture. Despite MLL proteins being postulated as essential for normal development, little is known about the specific functions of the different MLL lysine methyltransferases. Here we report heterozygous variants in the gene KMT2B (also known as MLL4) in 27 unrelated individuals with a complex progressive childhood-onset dystonia, often associated with a typical facial appearance and characteristic brain magnetic resonance imaging findings. Over time, the majority of affected individuals developed prominent cervical, cranial and laryngeal dystonia. Marked clinical benefit, including the restoration of independent ambulation in some cases, was observed following deep brain stimulation (DBS). These findings highlight a clinically recognizable and potentially treatable form of genetic dystonia, demonstrating the crucial role of KMT2B in the physiological control of voluntary movement.Funding for the project was provided by the Wellcome Trust for UK10K (WT091310) and DDD Study. The DDD study presents independent research commissioned by the Health Innovation Challenge Fund [grant number HICF-1009-003] - see www.ddduk.org/access.html for full acknowledgement. This work was supported in part by the Intramural Research Program of the National Human Genome Research Institute and the Common Fund, NIH Office of the Director. This work was supported in part by the German Ministry of Research and Education (grant nos. 01GS08160 and 01GS08167; German Mental Retardation Network) as part of the National Genome Research Network to A.R. and D.W. and by the Deutsche Forschungsgemeinschaft (AB393/2-2) to A.R. Brain expression data was provided by the UK Human Brain Expression Consortium (UKBEC), which comprises John A. Hardy, Mina Ryten, Michael Weale, Daniah Trabzuni, Adaikalavan Ramasamy, Colin Smith and Robert Walker, affiliated with UCL Institute of Neurology (J.H., M.R., D.T.), King’s College London (M.R., M.W., A.R.) and the University of Edinburgh (C.S., R.W.)

Von schnellen Teilchen und hellem Licht: 50 Jahre Deutsches Elektronen-Synchrotron DESY

Das 1959 in Hamburg als Zentrum für Elementarteilchenforschung gegründete "Deutsche Elektronen-Synchrotron DESY" gelangte durch Pionierleistungen in der Entwicklung von Hochenergie-Beschleunigern und Speicherringen zu weltweiter Anerkennung. Seiner internationalen Nutzergemeinde sind eine Reihe wichtiger Entdeckungen über die Materiebausteine Quarks und Gluonen und die Kräfte, welche die Welt im Innersten zusammenhalten, zu verdanken. Zusätzlich wurde die Synchrotronstrahlung für breite Anwendungsgebiete erschlossen und ihre Nutzung systematisch ausgebaut mit Ergebnissen, die gleichrangig neben denen in der Teilchenforschung stehen. Dieses Buch behandelt die Entwicklung des Forschungszentrums von den Anfängen bis in das Jahr 2003, in dem mit dem Beschluss zum Bau des Europäischen Röntgenlasers in Hamburg eine Änderung der Schwerpunktsetzung in der Beschleunigerentwicklung erfolgte, die seitdem auf neuartige Photonenquellen gerichtet ist. Die wichtigsten nachfolgenden Ereignisse werden ebenfalls kurz angesprochen

High energy electron-positron physics

With the termination of the physics program at PETRA, and with the start of TRISTAN and the SLC and later LEP, an era of e+e- physics has come to an end and a new one begins. The field is changing from a field of few specialists, to becoming one of the mainstream efforts of the high energy community. It seems appropriate at this moment to summarize what has been learned over the past years, in a way most useful to any high energy physicists, in particular to newcomers in the e+e- field. This is the purpose of the book. This book should be used as a reference for future workers in the field o