Estimate of the Collins fragmentation function in a chiral invariant approach

We predict the features of the Collins function, which describes the fragmentation of a transversely polarized quark into an unpolarized hadron, by modeling the fragmentation process at a low energy scale. We use the chiral invariant approach of Manohar and Georgi, where constituent quarks and Goldstone bosons are considered as effective degrees of freedom in the non-perturbative regime of QCD. To test the approach we calculate the unpolarized fragmentation function and the transverse momentum distribution of a produced hadron, both of which are described reasonably well. In the case of semi-inclusive deep-inelastic scattering, our estimate of the Collins function in connection with the transversity distribution gives rise to a transverse single spin asymmetry of the order of 10%, supporting the idea of measuring the transversity distribution of the nucleon in this way. In the case of e+ e- annihilation into two hadrons, our model predicts a Collins azimuthal asymmetry of about 5%.Comment: 12 pages, 15 figures. Figs. 11-14 changed, minor changes in discussion, few typos fixed and some references added. Final version to appear in PR

EFORT recommendations for off-label use, mix & match and mismatch in hip and knee arthroplasty

Off-label use is frequently practiced in primary and revision arthroplasty, as there may be indications for the application of implants for purposes outside the one the manufacturers intended.Under certain circumstances, patients may benefit from selective application of mix & match. This can refer to primary hip arthroplasty (if evidence suggests that the combination of devices from different manufacturers has superior results) and revision hip or knee arthroplasty (when the exchange of one component only is necessary and the invasiveness of surgery can be reduced).Within the EFORT 'Implant and Patient Safety Initiative', evidence-and consensus-based recommendations have been developed for the safe application of off-label use and mix & match in primary as well as revision hip and knee arthroplasty.Prior to the application of a medical device for hip or knee arthroplasty off-label and within a mix & match situation, surgeons should balance the risks and benefits to the patient, obtain informed consent, and document the decision process appropriately.Nevertheless, it is crucial for surgeons to only combine implants that are compatible. Mismatch of components, where their sizes or connections do not fit, may have catastrophic effects and is a surgical mistake.Surgeons must be fully aware of the features of the components that they use in off-label indications or during mix & match applications, must be appropriately trained and must audit their results.Considering the frequent practice of off-label and mix & match as well as the potential medico-legal issues, further research is necessary to obtain more data about the appropriate indications and outcomes for those procedures.Orthopaedics, Trauma Surgery and Rehabilitatio

Accessing transversity with interference fragmentation functions

We discuss in detail the option to access the transversity distribution function $h_1(x)$ by utilizing the analyzing power of interference fragmentation functions in two-pion production inside the same current jet. The transverse polarization of the fragmenting quark is related to the transverse component of the relative momentum of the hadron pair via a new azimuthal angle. As a specific example, we spell out thoroughly the way to extract $h_1(x)$ from a measured single spin asymmetry in two-pion inclusive lepton-nucleon scattering. To estimate the sizes of observable effects we employ a spectator model for the fragmentation functions. The resulting asymmetry of our example is discussed as arising in different scenarios for the transversity.Comment: 17 pages, 15 figures in .eps format included, typesetted in RevTeX and epsfig.sty, submitted to Phys. Rev.

Transverse Momentum Dependent Parton Distribution/Fragmentation Functions at an Electron-Ion Collider

We present a summary of a recent workshop held at Duke University on Partonic Transverse Momentum in Hadrons: Quark Spin-Orbit Correlations and Quark-Gluon Interactions. The transverse momentum dependent parton distribution functions (TMDs), parton-to-hadron fragmentation functions, and multi-parton correlation functions, were discussed extensively at the Duke workshop. In this paper, we summarize first the theoretical issues concerning the study of partonic structure of hadrons at a future electron-ion collider (EIC) with emphasis on the TMDs. We then present simulation results on experimental studies of TMDs through measurements of single spin asymmetries (SSA) from semi-inclusive deep-inelastic scattering (SIDIS) processes with an EIC, and discuss the requirement of the detector for SIDIS measurements. The dynamics of parton correlations in the nucleon is further explored via a study of SSA in D (`D) production at large transverse momenta with the aim of accessing the unexplored tri-gluon correlation functions. The workshop participants identified the SSA measurements in SIDIS as a golden program to study TMDs in both the sea and valence quark regions and to study the role of gluons, with the Sivers asymmetry measurements as examples. Such measurements will lead to major advancement in our understanding of TMDs in the valence quark region, and more importantly also allow for the investigation of TMDs in the sea quark region along with a study of their evolution.Comment: 44 pages 23 figures, summary of Duke EIC workshop on TMDs accepted by EPJ

On the Perturbative Stability of the QCD Predictions for the Ratio R=FL/FTR=F_L/F_T in Heavy-Quark Leptoproduction

We analyze the perturbative and parametric stability of the QCD predictions for the Callan-Gross ratio $R(x,Q^2)=F_L/F_T$ in heavy-quark leptoproduction. We consider the radiative corrections to the dominant photon-gluon fusion mechanism. In various kinematic regions, the following contributions are investigated: exact NLO results at low and moderate $Q^2\lesssim m^2$, asymptotic NLO predictions at high $Q^2\gg m^2$, and both NLO and NNLO soft-gluon (or threshold) corrections at large Bjorken $x$. Our analysis shows that large radiative corrections to the structure functions $F_T(x,Q^2)$ and $F_L(x,Q^2)$ cancel each other in their ratio $R(x,Q^2)$ with good accuracy. As a result, the NLO contributions to the Callan-Gross ratio are less than 10% in a wide region of the variables $x$ and $Q^2$. We provide compact LO predictions for $R(x,Q^2)$ in the case of low $x\ll 1$. A simple formula connecting the high-energy behavior of the Callan-Gross ratio and low-$x$ asymptotics of the gluon density is derived. It is shown that the obtained hadron-level predictions for $R(x\to 0,Q^2)$ are stable under the DGLAP evolution of the gluon distribution function. Our analytic results simplify the extraction of the structure functions $F_2^c(x,Q^2)$ and $F_2^b(x,Q^2)$ from measurements of the corresponding reduced cross sections, in particular at DESY HERA.Comment: 14 pages, 6 figures, revtex4; minor correction

Collider aspects of flavour physics at high Q

This review presents flavour related issues in the production and decays of heavy states at LHC, both from the experimental side and from the theoretical side. We review top quark physics and discuss flavour aspects of several extensions of the Standard Model, such as supersymmetry, little Higgs model or models with extra dimensions. This includes discovery aspects as well as measurement of several properties of these heavy states. We also present public available computational tools related to this topic.Comment: Report of Working Group 1 of the CERN Workshop ``Flavour in the era of the LHC'', Geneva, Switzerland, November 2005 -- March 200

Point View in Bird and Flower Painting

在中国传统绘画中，点景是极其重要的一种表达方式。石涛所研究的绘画问题中，情感、理性、力量都是不可缺少的，如何恰当地运用这三者，却有可能导致完全不同的创作结果。而点景正是这三者的集合点，不仅要用心灵去感受自然对象的内在精神，不能因为对象的限制而使感受层次也受到限制，把眼睛之受升华为心理之受。在绘画作品中合理地运用点景能使画家的情感与物象更加融合，画家自身的主观感受在画面上得到充分的体现，以一种小的特殊表现符号流露出画家作品里表达的象征倾向和审美概念，对画面的构图及意境有着画龙点睛的作用。本文以花鸟画点景为研究对象，重点介绍了点景的表现与意义；进一步阐述了点景在传统花鸟画构成中的作用，着重论述其在...The “point view” is extremely important as a means of expression in the traditional Chinese painting. Emotion, rationality and power are essential in the Shi Tao studied painting, and how to properly use them may lead to the creation of a completely different result. For the reason that “point view” is a collection of these three points, shouldn’t we only use the soul to feel the inner spirit of n...学位：文学硕士院系专业：艺术教育学院美术系_美术学学号：1862007115166

Повышение уровня ионов металла в крови пациентов после эндопротезирования: клинические случаи

We report on several clinical cases of different appearance and complications of patients after THR with metal-on-metal (MoM) couplings or a revision knee system. There may be skin irritation mainly due to chromium hypersensitivity or systemic effects and even cobalt intoxication can appear. We recommend clinical control to patients with MoM and a head size of 36 mm or larger or with knee revision systems. Patients who have problems such as pain or mal positioning should have measured the metall ion levels of cobalt. A serum cobalt level of 7 g /L indicates possible periprosthetic metallosis and may cause trouble. A normal serum cobalt level is below 1 g /L. We also need an MRI with Metal-Artifact-Reduced-Sequences or if not possible an ultrasound investigation to detect pseudotumors around the hip joint. For the clinical investigation you should look and ask for general hypersensitivity reaction (skin rash), cardiomyopathy, neurological changes including sensory changes, renal function impairment or thyroid dysfunction which may occur in cobalt intoxication. To optimize the diagnostic histological investigations using the Krenn classification are extremely helpful.Описано несколько клинических наблюдений пациентов с различными проявлениями и осложнениями после эндопротезирования тазобедренного сустава парой трения металл-металл или ревизионной артропластики коленного сустава. У таких больных может появиться раздражение кожи, в основном вследствие гиперчувствительности к хрому, и даже интоксикация кобальтом. Авторы рекомендуют проводить клиническое наблюдение за пациентами, которым установлены эндопротезы тазобедренного сустава с парой трения металл-металл и головками диаметром 36 и более мм, а также за больными после ревизионного эндопротезирования коленного сустава. У пациентов с болевым синдромом и неправильным положением компонентов эндопротеза необходимо определить уровень металлических ионов кобальта. Уровень кобальта в сыворотке крови свыше 7 мкг/л свидетельствует о наличии перипротезного металлоза, так как в норме этот показатель составляет менее 1 мкг/л. Для выявления псевдоопухолей в области тазобедренного сустава следует применять МРТ с использованием программы MARS (metal artifact reduction sequences), направленной на устранение искажений изображений и артефактов, возникающих из-за присутствия в магнитном поле металлических имплантатов. При отсутствии такой возможности можно выполнять ультразвуковое исследование. Во время клинического исследования необходимо определить наличие у пациента общей реакции гиперчувствительности (кожная сыпь), кардиомиопатии, неврологических нарушений, включая нарушения чувствительности, ухудшения функции почек или щитовидной железы, которые могут произойти вследствие интоксикации кобальтом. Оптимизировать гистологические исследования помогает использование классификации Кренна, которая приводится в тексте статьи

The influence of metallic ions from CoCr28Mo6 on the osteogenic differentiation and cytokine release of human osteoblasts

Inflammatory reactions associated with osteolysis and implant loosening can be the result of generated CoCr particles and the simultaneous release of ions, which are the consequence of wear at the articulating surfaces of metallic implants. By now, there is little knowledge about the influence of CoCr ions on the viability of human osteoblasts (hOB)

Partial or full component exchange in hip revision? The relevance of off-label use and mix & match

Off-label use is frequently practiced in hip revision arthroplasty, as there may be indications for the application of implants for purposes outside the one the manufacturers intended (i.e. large bone and soft tissue defects, obesity). Patients may also benefit from selective application of mix & match in hip revision, when the exchange of one component only is necessary and the invasiveness of surgery can be reduced. Currently, there are no formal guidelines for these situations. Therefore, within a recent EFORT initiative, evidence- and consensus-based recommendations have been developed for the safe application of off-label use and mix & match in revision hip and knee arthroplasty.Orthopaedics, Trauma Surgery and Rehabilitatio