Superantigen architecture: Functional decoration on a conserved scaffold

A defining and consistent feature of the bacterial superantigens from Staphylococcus aureus and Streptococcus pyogenes is their strongly conserved three-dimensional structure. Structural studies to date show that the array of more than 280 amino acid sequences known for superantigens (SAgs) and staphylococcal superantigen-like (SSL) proteins all have the same fold-a structure in which the same three-dimensional arrangement of α-helices and β-sheets is traced by each amino acid sequence, with the same topology (for recent reviews, see references 29 and 43). A typical SAg structure comprises two domains-an N-terminal β -barrel domain called an OB-fold (4, 25) and a C-terminal β-grasp domain in which a long α-helix packs on to a mixed parallel and antiparallel β-sheet. These two domains are traversed by an α-helix that lies at the N terminus of the protein and packs against the β-grasp domain, thus linking the N- and C-terminal domains

Confinement: Understanding the Relation Between the Wilson Loop and Dual Theories of Long Distance Yang Mills Theory

In this paper we express the velocity dependent, spin dependent heavy quark potential $V_{q\bar q}$ in QCD in terms of a Wilson Loop $W(\Gamma)$ determined by pure Yang Mills theory. We use an effective dual theory of long-distance Yang Mills theory to calculate $W(\Gamma)$ for large loops; i.e. for loops of size $R > R_{FT}$. ($R_{FT}$ is the flux tube radius, fixed by the value of the Higgs (monopole) mass of the dual theory, which is a concrete realization of the Mandelstam 't Hooft dual superconductor mechanism of confinement). We replace $W(\Gamma)$ by $W_{eff}(\Gamma)$, given by a functional integral over the dual variables, which for $R > R_{FT}$ can be evaluated by a semiclassical expansion, since the dual theory is weakly coupled at these distances. The classical approximation gives the leading contribution to $W_{eff}(\Gamma)$ and yields a velocity dependent heavy quark potential which for large $R$ becomes linear in $R$, and which for small $R$ approaches lowest order perturbative QCD. This latter fact means that these results should remain applicable down to distances where radiative corrections giving rise to a running coupling constant become important. The spin dependence of the potential reflects the vector coupling of the quarks at long range as well as at short range. The methods developed here should be applicable to any realization of the dual superconductor mechanism. They give an expression determining $W_{eff}(\Gamma)$ independent of the classical approximation, but semi classical corrections due to fluctuations of the flux tube are not worked out in this paper. Taking these into account should lead to an effective string theory free from the conformal anomaly.Comment: 39 pages, latex2e, 1 figure(fig.eps

Delivery of patient education and support using an online digital platform for patients undergoing primary hip and knee replacement: The patient’s perspectives

The aim of the present evaluation was to evaluate the use of an online digital platform (ODP) to deliver patient education and support (PES) to patients undergoing total hip replacement (THR) and total knee replacement (TKR) surgery. Six objectives were outlined to assess the following areas: patient engagement; ease of use; understanding of information; quantity of information; aid of recovery; suggestions for improvements. A qualitative service evaluation of the ODP. Participants included patients who were registered to the platform for THR or TKR, were at least 90 days post-surgery and had accessed at least one carepac. Interviews followed a semi-structured schedule and were transcribed and analysed using thematic analysis. A total of 14 participants were interviewed. Three main themes were identified, each with subsequent sub-themes. (1) Health behaviours – internal control of own health, external email prompts, social support. (2) Contribution to recovery – quantity and quality of information available, structured program, suggestions of improvements to better aid recovery. (3) PES delivery – ease of use and accessibility of an ODP, technology advancements, alternative methods of PES. The online PES platform was beneficial for patients undergoing THR and TKR surgery. It aided their understanding of and preparedness for joint replacement surgery, as well as being a supportive tool for rehabilitation and recovery. All patients actively engaged with the ODP and in doing so, developed a greater understanding as a result of the detailed and structured carepacs assigned. Experience Framework This article is associated with the Patient, Family & Community Engagement lens of The Beryl Institute Experience Framework (https://www.theberylinstitute.org/ExperienceFramework). Access other PXJ articles related to this lens. Access other resources related to this lens

Persistence of Problematic Sexual Behaviors in Children

The purpose of this study was to identify personal and family predictors and correlates of persistence of problematic sexual behaviors (PSB) in children. Participants were the families of 49 children (ages 4–11 years) referred by Child Protective Services in 4 administrative districts of Quebec. Caregivers completed interviews and questionnaires twice at a 1-year interval. Results showed that 43% of children persisted with PSB. When age was controlled, greater exposure to sexualized behaviors in the family proved both a correlate and a predictor of PSB persistence in children 12 months later.\ud Externalizing problems and somatic complaints emerged as correlates of PSB as well. Maltreatment subtypes did not predict PSB persistence

Winter wheat: A model for the simulation of growth and yield in winter wheat

The basic ideas and constructs for a general physical/physiological process level winter wheat simulation model are documented. It is a materials balance model which calculates daily increments of photosynthate production and respiratory losses in the crop canopy. The partitioning of the resulting dry matter to the active growing tissues in the plant each day, transpiration and the uptake of nitrogen from the soil profile are simulated. It incorporates the RHIZOS model which simulates, in two dimensions, the movement of water, roots, and soluble nutrients through the soil profile. It records the time of initiation of each of the plant organs. These phenological events are calculated from temperature functions with delays resulting from physiological stress. Stress is defined mathematically as an imbalance in the metabolite supply; demand ratio. Physiological stress is also the basis for the calculation of rates of tiller and floret abortion. Thus, tillering and head differentiation are modeled as the resulants of the two processes, morphogenesis and abortion, which may be occurring simulaneously

Lattice Monte Carlo calculations for unitary fermions in a finite box

We perform lattice Monte Carlo simulations for up to 66 unitary fermions in a finite box using a highly improved lattice action for nonrelativistic spin 1/2 fermions. We obtain a value of $0.366^{+0.016}_{-0.011}$ for the Bertsch parameter, defined as the energy of the unitary Fermi gas measured in units of the free gas energy in the thermodynamic limit. In addition, for up to four unitary fermions, we compute the spectrum of the lattice theory by exact diagonalization of the transfer matrix projected onto irreducible representations of the octahedral group for small to moderate size lattices, providing an independent check of our few-body simulation results. We compare our exact numerical and simulation results for the spectrum to benchmark studies of other research groups, as well as perform an extended analysis of our lattice action improvement scheme, including an analysis of the errors associated with higher partial waves and finite temporal discretization.Comment: Significant revisions from previous version. Included data at a larger volume and performed an infinite volume extrapolation of the Bertsch parameter. Published versio

Capture zones of the family of functions lambda z^m exp(z)

We consider the family of entire transcendental maps given by $F_{\lambda,m}= \lambda z^m exp(z)$ where m>=2. All functions $F_{\lambda,m}$ have a superattracting fixed point at z=0, and a critical point at z=-m. In the dynamical plane we study the topology of the basin of attraction of z=0. In the parameter plane we focus on the capture behaviour, i.e., \lambda values such that the critical point belongs to the basin of attraction of z=0. In particular, we find a capture zone for which this basin has a unique connected component, whose boundary is then non-locally connected. However, there are parameter values for which the boundary of the immediate basin of z=0 is a quasicircle.Comment: 25 pages, 14 figures. Accepted for publication in the International Journal of bifurcation and Chao

Cooperative program for design, fabrication, and testing of graphite/epoxy composite helicopter shafting

The fabrication of UH-1 helicopter tail rotor drive shafts from graphite/epoxy composite materials is discussed. Procedures for eliminating wrinkles caused by lack of precure compaction are described. The development of the adhesive bond between aluminum end couplings and the composite tube is analyzed. Performance tests to validate the superiority of the composite materials are reported