Wakimoto realizations of current algebras: an explicit construction

A generalized Wakimoto realization of $\widehat{\cal G}_K$ can be associated with each parabolic subalgebra ${\cal P}=({\cal G}_0 +{\cal G}_+)$ of a simple Lie algebra ${\cal G}$ according to an earlier proposal by Feigin and Frenkel. In this paper the proposal is made explicit by developing the construction of Wakimoto realizations from a simple but unconventional viewpoint. An explicit formula is derived for the Wakimoto current first at the Poisson bracket level by Hamiltonian symmetry reduction of the WZNW model. The quantization is then performed by normal ordering the classical formula and determining the required quantum correction for it to generate $\widehat{\cal G}_K$ by means of commutators. The affine-Sugawara stress-energy tensor is verified to have the expected quadratic form in the constituents, which are symplectic bosons belonging to ${\cal G}_+$ and a current belonging to ${\cal G}_0$. The quantization requires a choice of special polynomial coordinates on the big cell of the flag manifold $P\backslash G$. The effect of this choice is investigated in detail by constructing quantum coordinate transformations. Finally, the explicit form of the screening charges for each generalized Wakimoto realization is determined, and some applications are briefly discussed.Comment: 38 pages, LaTeX, contains improved formulations of theorems 3 and 6, two references and a remark added, plus minor stylistic change

An explicit construction of Wakimoto realizations of current algebras

It is known from a work of Feigin and Frenkel that a Wakimoto type, generalized free field realization of the current algebra $\widehat{\cal G}_k$ can be associated with each parabolic subalgebra ${\cal P}=({\cal G}_0+{\cal G}_+)$ of the Lie algebra ${\cal G}$, where in the standard case ${\cal G}_0$ is the Cartan and ${\cal P}$ is the Borel subalgebra. In this letter we obtain an explicit formula for the Wakimoto realization in the general case. Using Hamiltonian reduction of the WZNW model, we first derive a Poisson bracket realization of the ${\cal G}$-valued current in terms of symplectic bosons belonging to ${\cal G}_+$ and a current belonging to ${\cal G}_0$. We then quantize the formula by determining the correct normal ordering. We also show that the affine-Sugawara stress-energy tensor takes the expected quadratic form in the constituents.Comment: 13 pages, LaTeX; a typo corrected in (5.5-6), refs and a remark adde

Black holes as generalised Toda molecules

In this note we compare the geodesic formalism for spherically symmetric black hole solutions with the black hole effective potential approach. The geodesic formalism is beneficial for symmetric supergravity theories since the symmetries of the larger target space leads to a complete set of commuting constants of motion that establish the integrability of the geodesic equations of motion, as shown in arXiv:1007.3209. We point out that the integrability lifts straightforwardly to the integrability of the equations of motion with a black hole potential. This construction turns out to be a generalisation of the connection between Toda molecule equations and geodesic motion on symmetric spaces known in the mathematics literature. We describe in some detail how this generalisation of the Toda molecule equations arises.Comment: 19 pages, references adde

Heterologous Overexpression and Mutagenesis of the Human Bile Salt Export Pump (ABCB11) Using DREAM (Directed REcombination-Assisted Mutagenesis)

Homologous recombination in Saccharomyces cerevisiae is a well-studied process. Here, we describe a yeast-recombination-based approach to construct and mutate plasmids containing the cDNA of the human bile salt export pump (BSEP) that has been shown to be unstable in E. coli. Using this approach, we constructed the necessary plasmids for a heterologous overexpression of BSEP in the yeast Pichia pastoris. We then applied a new site-directed mutagenesis method, DREAM (Directed REcombination-Assisted Mutagenesis) that completely bypasses E. coli by using S. cerevisiae as the plasmid host with high mutagenesis efficiency. Finally, we show how to apply this strategy to unstable non-yeast plasmids by rapidly turning an existing mammalian BSEP expression construct into a S. cerevisiae-compatible plasmid and analyzing the impact of a BSEP mutation in several mammalian cell lines

A Novel Substrate-Based HIV-1 Protease Inhibitor Drug Resistance Mechanism

BACKGROUND: HIV protease inhibitor (PI) therapy results in the rapid selection of drug resistant viral variants harbouring one or two substitutions in the viral protease. To combat PI resistance development, two approaches have been developed. The first is to increase the level of PI in the plasma of the patient, and the second is to develop novel PI with high potency against the known PI-resistant HIV protease variants. Both approaches share the requirement for a considerable increase in the number of protease mutations to lead to clinical resistance, thereby increasing the genetic barrier. We investigated whether HIV could yet again find a way to become less susceptible to these novel inhibitors. METHODS AND FINDINGS: We have performed in vitro selection experiments using a novel PI with an increased genetic barrier (RO033-4649) and demonstrated selection of three viruses 4- to 8-fold resistant to all PI compared to wild type. These PI-resistant viruses did not have a single substitution in the viral protease. Full genomic sequencing revealed the presence of NC/p1 cleavage site substitutions in the viral Gag polyprotein (K436E and/or I437T/V) in all three resistant viruses. These changes, when introduced in a reference strain, conferred PI resistance. The mechanism leading to PI resistance is enhancement of the processing efficiency of the altered substrate by wild-type protease. Analysis of genotypic and phenotypic resistance profiles of 28,000 clinical isolates demonstrated the presence of these NC/p1 cleavage site mutations in some clinical samples (codon 431 substitutions in 13%, codon 436 substitutions in 8%, and codon 437 substitutions in 10%). Moreover, these cleavage site substitutions were highly significantly associated with reduced susceptibility to PI in clinical isolates lacking primary protease mutations. Furthermore, we used data from a clinical trial (NARVAL, ANRS 088) to demonstrate that these NC/p1 cleavage site changes are associated with virological failure during PI therapy. CONCLUSIONS: HIV can use an alternative mechanism to become resistant to PI by changing the substrate instead of the protease. Further studies are required to determine to what extent cleavage site mutations may explain virological failure during PI therapy

The TOP-SCOPE Survey of Planck Galactic Cold Clumps : Survey Overview and Results of an Exemplar Source, PGCC G26.53+0.17

The low dust temperatures (<14 K) of Planck Galactic cold clumps (PGCCs) make them ideal targets to probe the initial conditions and very early phase of star formation. "TOP-SCOPE" is a joint survey program targeting similar to 2000 PGCCs in J = 1-0 transitions of CO isotopologues and similar to 1000 PGCCs in 850 mu m continuum emission. The objective of the "TOP-SCOPE" survey and the joint surveys (SMT 10 m, KVN 21 m, and NRO 45 m) is to statistically study the initial conditions occurring during star formation and the evolution of molecular clouds, across a wide range of environments. The observations, data analysis, and example science cases for these surveys are introduced with an exemplar source, PGCC G26.53+0.17 (G26), which is a filamentary infrared dark cloud (IRDC). The total mass, length, and mean line mass (M/L) of the G26 filament are similar to 6200 M-circle dot, similar to 12 pc, and similar to 500 M-circle dot pc(-1), respectively. Ten massive clumps, including eight starless ones, are found along the filament. The most massive clump as a whole may still be in global collapse, while its denser part seems to be undergoing expansion owing to outflow feedback. The fragmentation in the G26 filament from cloud scale to clump scale is in agreement with gravitational fragmentation of an isothermal, nonmagnetized, and turbulent supported cylinder. A bimodal behavior in dust emissivity spectral index (beta) distribution is found in G26, suggesting grain growth along the filament. The G26 filament may be formed owing to large-scale compression flows evidenced by the temperature and velocity gradients across its natal cloud.Peer reviewe

Regulation of Coronary Blood Flow

The heart is uniquely responsible for providing its own blood supply through the coronary circulation. Regulation of coronary blood flow is quite complex and, after over 100 years of dedicated research, is understood to be dictated through multiple mechanisms that include extravascular compressive forces (tissue pressure), coronary perfusion pressure, myogenic, local metabolic, endothelial as well as neural and hormonal influences. While each of these determinants can have profound influence over myocardial perfusion, largely through effects on end-effector ion channels, these mechanisms collectively modulate coronary vascular resistance and act to ensure that the myocardial requirements for oxygen and substrates are adequately provided by the coronary circulation. The purpose of this series of Comprehensive Physiology is to highlight current knowledge regarding the physiologic regulation of coronary blood flow, with emphasis on functional anatomy and the interplay between the physical and biological determinants of myocardial oxygen delivery. © 2017 American Physiological Society. Compr Physiol 7:321-382, 2017

The abalysis of the run of sprinter by means of the software Dartfish

6 Abstract Title: The analysis of the run of sprinter by means of the software Dartfish Objectives: The objective of this thesis is the presentation of use of possibilities of software for the analysis of sport performance in the sprint for 100 m and consequently evaluation of the structure of sport performance in the sprint for 100 m in selected races Methods: The method of the analysis of the video recording by means of the software Dartfish and the method of comparison was used in the thesis. The method of analysis was applied for the recorded sprints for 100 m. The method of comparison was used for the mutual comparison of analysed sprints. The use of this programme was evaluated during acquiring data from the video recording. Results: I found out, that the software programme Dartfish is fully suitable for the analysis of sport performances in the sprints for 100 m. The outstanding positive part is also the fact, that this software product enables both qualitative and quantitative analysis and fully discloses the structure of run. The programme could be also applied in the training process, where it could be used for the improvement of the run technique due to great quantity of quality feedback information which it provides. Keywords: sport performance, athletics, sprint, structure of sport performance,..

Verwendung einer mit Hilfe des Programms Dartfish erarbeiteten Videoanalyse im Sportunterricht

Tento příspěvek je koncipován jako rešeršní studie. Data pro tuto studii byla získána zejména ze zahraničních publikací. Publikace byly vyhledávány převážně pomocí internetových databází. Příspěvek stručně ukazuje možnosti využití programu Dartfish ve školní tělesné výchově a v lekcích sportovních specializací na sportovních školách. Zatímco je technologie často obviňována za pokles fyzické aktivity v naší společnosti, může také pomoci studentům rozvíjet a zkvalitnit jejich motorické dovednosti. Využívání videoanalýzy zpracované pomocí programu Dartfish se může stát moderní metodou, jak se snadno a rychle naučit složité pohybové vzorce. Studování pohybu s programem Dartfish se pro současné studenty stává zábavou a může podnítit studenty k podrobnějšímu zkoumání pohybu. Tento příspěvek ukazuje, že učení a uchovávání motorických dovedností se při využití programu Dartfish zlepšuje s kvantitou a kvalitou zpětnovazebných informací během a po skončení daného cvičení.Niniejszy artykuł ma charakter opracowania przeglądowego. Dane do opracowania pozyskano przede wszystkim z literatury zagranicznej. Publikacji wyszukiwano przede wszystkim przy pomocy internetowych baz danych. Artykuł zwięźle przedstawia możliwości wykorzystania programu Dartfisch na szkolnych lekcjach wychowania fizycznego oraz na zajęciach specjalizacji sportowych w szkołach o profilu sportowym. Chociaż postępowi techniki często przypisywana jest przyczyna obniżenia aktywności fizycznej w naszym społeczeństwie, to może także studentom pomóc w rozwijaniu i doskonaleniu ich zdolności motorycznych. Wykorzystanie analizy wideo opracowanej przy pomocy programu Dartfisch może stać się nowoczesną metodą łatwego i szybkiego uczenia się skomplikowanych wzorców ruchowych. Studiowanie ruchu z programem Dartfish staje się dla współczesnych studentów zabawą, mogąc ich zachęcać do bardziej szczegółowego analizowania ruchu. Niniejszy artykuł pokazuje, iż uczenie się i utrzymanie umiejętności motorycznych przy wykorzystaniu programu Dartfisch poprawia się wraz z jakością i ilością zwrotnych informacji otrzymywanych w trakcie i po zakończeniu danego ćwiczenia.This entry is drawn like exploration of facts. Data was primarily obtained from foreign publications, where I found them at the databases. This entry briefly shows possibilities of using program Dartfish in physical education and in lessons of sports specialization at sport schools. While technology is most often blamed for the decrease in physical activity in our society, technology can also be used to help students develop and refine motor skills. Using of Dartfish video analysis could become a modern way how to teach complex kinetic figures easily. Study of the movements with program Dartfish is an amusement for contempory students and it can urge students to a deep research. This entry can show that learning and retention of motor skills with using of program Dartfish is improved by quantity and quality of feedback during and after execution of such skills.Dieser Beitrag ist als Recherchestudie konzipiert. Die Daten für diese Studie wurden vorwiegend aus ausländischen Publikationen gewonnen. Die Publikationen wurden hauptsächlich mit Hilfe von Internetdatenbanken herausgesucht. Der Beitrag zeigt kurz die Möglichkeiten der Nutzung des Programms Dartfish im Sportunterricht und in den Lektionen der sportlichen Spezialisierung an Sportschulen. Während der Technologie oft die Schuld am Rückgang der körperlichen Aktivität in unserer Gesellschaft gegeben wird, kann sie Schülern auch helfen, ihre motorische Geschicklichkeit zu entwickeln und zu verbessern. Die Verwendung der mit Hilfe des Programms Dartfish erarbeiteten Videoanalyse kann ein modernes Verfahren werden, wie man leicht und schnell komplizierte Bewegungsmuster lernt. Das Studieren der Bewegung mit dem Programm Dartfish wird den heutigen Schülern Spaß machen und kann sie zu einer ausführlicheren Erforschung von Bewegungen anregen. Dieser Beitrag zeigt, dass sich das Lernen und Beibehalten der motorischen Geschicklichkeiten bei der Verwendung des Programms Dartfish mit der Quantität und der Qualität der Rückkopplungsinformationen während und nach dem Ende der betreffenden Übung verbesser