Massless monopoles and the moduli space approximation

We investigate the applicability of the moduli space approximation in theories with unbroken non-Abelian gauge symmetries. Such theories have massless magnetic monopoles that are manifested at the classical level as clouds of non-Abelian field surrounding one or more massive monopoles. Using an SO(5) example with one massive and one massless monopole, we compare the predictions of the moduli space approximation with the results of a numerical solution of the full field equations. We find that the two diverge when the cloud velocity becomes of order unity. After this time the cloud profile approximates a spherical wavefront moving at the speed of light. In the region well behind this wavefront the moduli space approximation continues to give a good approximation to the fields. We therefore expect it to provide a good description of the motion of the massive monopoles and of the transfer of energy between the massive and massless monopoles.Comment: 18 pages, 5 figure

More on scattering of Chern-Simons vortices

I derive a general formalism for finding kinetic terms of the effective Lagrangian for slowly moving Chern-Simons vortices. Deformations of fields linear in velocities are taken into account. From the equations they must satisfy I extract the kinetic term in the limit of coincident vortices. For vortices passing one over the other there is locally the right-angle scattering. The method is based on analysis of field equations instead of action functional so it may be useful also for nonvariational equations in nonrelativistic models of Condensed Matter Physics.Comment: discussion around Eq.(45) is generalised, one more condition for the local right-angle scattering is adde

UB Online Courses: An On-Demand Video-Streaming Service for Online Education

Online education in the past few years has become a very convenient and cost-effective alternative to the traditional class-based education offered on college and university campuses. Its popularity can been seen in the increasing number of online courses being offered by many universities around the world; and the University of Bridgeport is no exception. To handle the increasing demand on online education programs, the current methods and technologies need to be improved to meet the student expectations of ease of use, accessibility and availability. In this work we’re addressing issues in the current online education services provided at UB, such as the standardization of video formats, making the lecture videos viewable on smart phone devices, and making all courses available in a central location

Hyperbolic calorons, monopoles, and instantons

We construct families of SO(3)-symmetric charge 1 instantons and calorons on the space H^3 x R. We show how the calorons include instantons and hyperbolic monopoles as limiting cases. We show how Euclidean calorons are the flat space limit of this family.Comment: 11 pages, no figures 1 reference added Published version available at: http://www.springerlink.com/content/k0j4815u54303450

UK-based, multisite, prospective cohort study of small bowel obstruction in acute surgical services: National Audit of Small Bowel Obstruction (NASBO) protocol

Introduction Small bowel obstruction (SBO) is a common indication for emergency laparotomy in the UK, which is associated with a 90-day mortality rate of 13%. There are currently no UK clinical guidelines for the management of this condition. The aim of this multicentre prospective cohort study is to describe the burden, variation in management and associated outcomes of SBO in the UK adult population. Methods and analysis UK hospitals providing emergency general surgery are eligible to participate. This study has three components: (1) a clinical preference questionnaire to be completed by consultants providing emergency general surgical care to assesses preferences in diagnostics and therapeutic approaches, including laparoscopy and nutritional interventions; (2) site resource profile questionnaire to indicate ease of access to diagnostic services, operating theatres, nutritional support teams and postoperative support including intensive care; (3) prospective cohort study of all cases of SBO admitted during an 8-week period at participating trusts. Data on diagnostics, operative and nutritional interventions, and in-hospital mortality and morbidity will be captured, followed by data validation. Ethics and dissemination This will be conducted as a national audit of practice in conjunction with trainee research collaboratives, with support from patient representatives, surgeons, anaesthetists, gastroenterologists and a clinical trials unit. Site-specific reports will be provided to each participant site as well as an overall report to be disseminated through specialist societies. Results will be published in a formal project report endorsed by stakeholders, and in peer-reviewed scientific reports. Key findings will be debated at a focused national meeting with a view to quality improvement initiatives

Photon-Phonon-assisted tunneling through a single-molecular quantum dot

Based on exactly mapping of a many-body electron-phonon interaction problem onto a one-body problem, we apply the well-established nonequilibrium Green function technique to solve the time-dependent phonon-assisted tunneling at low temperature through a single-molecular quantum dot connected to two leads, which is subject to a microwave irradiation field. It is found that in the presence of the electron-phonon interaction and the microwave irradiation field, the time-average transmission and the nonlinear differential conductance display additional peaks due to pure photon absorption or emission processes and photon-absorption-assisted phonon emission processes. The variation of the time-average current with frequency of the microwave irradiation field is also studied.Comment: 9 pages, 6 figures, submitted to Phys. Rev. B. accepted by Phys. Rev.

Exploiting vulnerabilities of cancer by targeting nuclear receptors of stromal cells in tumor microenvironment.

The tumor microenvironment is a complex and dynamic cellular community comprising the tumor epithelium and various tumor-supporting cells such as immune cells, fibroblasts, immunosuppressive cells, adipose cells, endothelial cells, and pericytes. The interplay between the tumor microenvironment and tumor cells represents a key contributor to immune evasiveness, physiological hardiness and the local and systemic invasiveness of malignant cells. Nuclear receptors are master regulators of physiological processes and are known to play pro-/anti-oncogenic activities in tumor cells. However, the actions of nuclear receptors in tumor-supporting cells have not been widely studied. Given the excellent druggability and extensive regulatory effects of nuclear receptors, understanding their biological functionality in the tumor microenvironment is of utmost importance. Therefore, the present review aims to summarize recent evidence about the roles of nuclear receptors in tumor-supporting cells and their implications for malignant processes such as tumor proliferation, evasion of immune surveillance, angiogenesis, chemotherapeutic resistance, and metastasis. Based on findings derived mostly from cell culture studies and a few in vivo animal cancer models, the functions of VDR, PPARs, AR, ER and GR in tumor-supporting cells are relatively well-characterized. Evidence for other receptors, such as RARβ, RORγ, and FXR, is limited yet promising. Hence, the nuclear receptor signature in the tumor microenvironment may harbor prognostic value. The clinical prospects of a tumor microenvironment-oriented cancer therapy exploiting the nuclear receptors in different tumor-supporting cells are also encouraging. The major challenge, however, lies in the ability to develop a highly specific drug delivery system to facilitate precision medicine in cancer therapy