Bystander B cells rapidly acquire antigen receptors from activated B cells by membrane transfer: a novel mechanism for enhancing specific antigen presentation

The B cell antigen receptor (BCR) efficiently facilitates the capture and processing of a specific antigen for presentation on MHC class II molecules to antigen specific CD4+ T cells (1). Despite this, the majority of B cells are only thought to play a limited role in CD4+ T cell activation since BCRs are clonotypically expressed. Here we show, however, that activated B cells can, both in vitro and in vivo, rapidly donate their BCR to bystander B cells, a process that is mediated by direct membrane transfer between adjacent B cells and is amplified by the interaction of the BCR with specific antigen. This results in a dramatic expansion in the number of antigen-binding B cells in vivo, with the transferred BCR endowing recipient B cells with the ability to present specific antigen to antigen-specific CD4+ T cells

A comparative analysis of Simplified General Circulation Models of the atmosphere of Venus

Within the context of a working group supported by ISSI (Bern, Switzerland), we have made an intercomparison work between Global Circulation Models using simpli?ed parameterizations for radiative forcing and other physical processes. Even with similar schemes and parameters, the different GCMs produce different circulations, illustrating interesting differences between dynamical model cores

Observation of an orbital interaction-induced Feshbach resonance in 173-Yb

We report on the experimental observation of a novel inter-orbital Feshbach resonance in ultracold 173-Yb atoms, which opens the possibility of tuning the interactions between the 1S0 and 3P0 metastable state, both possessing vanishing total electronic angular momentum. The resonance is observed at experimentally accessible magnetic field strengths and occurs universally for all hyperfine state combinations. We characterize the resonance in the bulk via inter-orbital cross-thermalization as well as in a three-dimensional lattice using high-resolution clock-line spectroscopy.Comment: 5 pages, 4 figure

Shuttle-launch triangular space station

A triangular space station deployable in orbit is described. The framework is comprized of three trusses, formed of a pair of generally planar faces consistine of foldable struts. The struts expand and lock into rigid structural engagement forming a repetition of equilater triangles and nonfolding diagonal struts interconnecting the two faces. The struts are joined together by node fittings. The framework can be packaged into a size and configuration transportable by a space shuttle. When deployed, the framework provides a large work/construction area and ample planar surface area for solar panels and thermal radiators. A plurity of modules are secured to the framework and then joined by tunnels to make an interconnected modular display. Thruster units for the space station orientation and altitude maintenance are provided

A Pseudonymous Peer-2-Peer Review System for Child Protection On-line

Children are using the internet more and more, and from a younger age. This is despite the commonly known dangers of predators. There is no policing of the internet, nor would it be possible to instigate. Parents are in the difficult position of trying to monitor and control their children’s internet USAge, when more often than not the children know the technology better than they do. This can lead to either ineffective measures, or measures that the children will deliberately circumvent for their own privacy. There are also technical issues that are far from trivial. The problem of distinguishing the dialogue of a child from a predator pretending to be a child is extremely difficult. This paper presents a solution which can accurately identify threats, while satisfying the apparently conflicting needs for safety of, and privacy for, the children

Pairing in spin polarized two-species fermionic mixtures with mass asymmetry

We discuss on the pairing mechanism of fermions with mismatch in their fermi momenta due to a mass asymmetry. Using a variational ansatz for the ground state we also discuss the BCS -BEC crossover of this system. It is shown that the breached pairing solution with a single fermi surface is stable in the BEC regime. We also include the temperatures effect on the fermion pairing within an approximation that is valid for temperatures much below the critical temperature.Comment: 8 pages and 6 figures, few typos corrected, version to appear in EPJ

Linear magnetoresistance in commercial n-type silicon due to inhomogeneous doping

Free electron theory tells us that resistivity is independent of magnetic field. In fact, most observations match the semiclassical prediction of a magnetoresistance that is quadratic at low fields before saturating. However, a non-saturating linear magnetoresistance has been observed in exotic semiconductors such as silver chalcogenides, lightly-doped InSb, N-doped InAs, MnAs-GaAs composites, PrFeAsO, and epitaxial graphene. Here we report the observation of a large linear magnetoresistance in the ohmic regime in commonplace commercial n-type silicon wafer. It is well-described by a classical model of spatially fluctuating donor densities, and may be amplified by altering the aspect ratio of the sample to enhance current-jetting: increasing the width tenfold increased the magnetoresistance at 8 T from 445 % to 4707 % at 35 K. This physical picture may well offer insights into the large magnetoresistances recently observed in n-type and p-type Si in the non-ohmic regime.Comment: submitted to Nature Material

Asymmetric Fermi superfluid with different atomic species in a harmonic trap

We study the dilute fermion gas with pairing between two species and unequal concentrations in a harmonic trap using the mean field theory and the local density approximation. We found that the system can exhibit a superfluid shell structure sandwiched by the normal fermions. This superfluid shell structure occurs if the mass ratio is larger then certain critical value which increases from the weak-coupling BCS region to the strong-coupling BEC side. In the strong coupling BEC regime, the radii of superfluid phase are less sensitive to the mass ratios and are similar to the case of pairing with equal masses. However, the lighter leftover fermions are easier to mix with the superfluid core than the heavier ones. A partially polarized superfluid can be found if the majority fermions are lighter, whereas phase separation is still found if they are heavier.Comment: 12 pages, 7 figure

Ultra-cold Polarized Fermi Gases

Recent experiments with ultra-cold atoms have demonstrated the possibility of realizing experimentally fermionic superfluids with imbalanced spin populations. We discuss how these developments have shed a new light on a half- century old open problem in condensed matter physics, and raised new interrogations of their own.Comment: 27 pages; 8 figures; Published in Report in Rep. Prog. Phys. 73 112401 (2010

The effectiveness of manual stretching in the treatment of plantar heel pain: a systematic review

Background: Plantar heel pain is a commonly occurring foot complaint. Stretching is frequently utilised as a treatment, yet a systematic review focusing only on its effectiveness has not been published. This review aimed to assess the effectiveness of stretching on pain and function in people with plantar heel pain. Methods: Medline, EMBASE, CINAHL, AMED, and The Cochrane Library were searched from inception to July 2010. Studies fulfilling the inclusion criteria were independently assessed, and their quality evaluated using the modified PEDro scale. Results: Six studies including 365 symptomatic participants were included. Two compared stretching with a control, one study compared stretching to an alternative intervention, one study compared stretching to both alternative and control interventions, and two compared different stretching techniques and durations. Quality rating on the modified Pedro scale varied from two to eight out of a maximum of ten points. The methodologies and interventions varied significantly between studies, making meta-analysis inappropriate. Most participants improved over the course of the studies, but when stretching was compared to alternative or control interventions, the changes only reached statistical significance in one study that used a combination of calf muscle stretches and plantar fascia stretches in their stretching programme. Another study comparing different stretching techniques, showed a statistically significant reduction in some aspects of pain in favour of plantar fascia stretching over calf stretches in the short term. Conclusions: There were too few studies to assess whether stretching is effective compared to control or other interventions, for either pain or function. However, there is some evidence that plantar fascia stretching may be more effective than Achilles tendon stretching alone in the short-term. Appropriately powered randomised controlled trials, utilizing validated outcome measures, blinded assessors and long-term follow up are needed to assess the efficacy of stretching