47,530 research outputs found
Microscopes and computers combined for analysis of chromosomes
Scanning machine CHLOE, developed for photographic use, is combined with a digital computer to obtain quantitative and statistically significant data on chromosome shapes, distribution, density, and pairing. CHLOE permits data acquisition about a chromosome complement to be obtained two times faster than by manual pairing
Online reflective diaries - using technology to strengthen the learning experience
Internet based technologies have benefits for students and staff in terms of time and information sharing. Students at the University of Glasgow were required to engage in reflective writing, with tutor support, as part of their course assessment. We examine the benefits of this approach in fostering a deep, holistic approach to learning, student contribution to course development through this reflection, and the issues in support of these activities
The structural response of unsymmetrically laminated composite cylinders
The responses of an unsymmetrically laminated fiber-reinforced composite cylinder to an axial compressive load, a torsional load, and the temperature change associated with cooling from the processing temperature to the service temperature are investigated. These problems are considered axisymmetric and the response is studied in the context of linear elastic material behavior and geometrically linear kinematics. Four different laminates are studied: a general unsymmetric laminate; two unsymmetric but more conventional laminates; and a conventional quasi-isotropic symmetric laminate. The responses based on closed-form solutions for different boundary conditions are computed and studied in detail. Particular emphasis is directed at understanding the influence of elastic couplings in the laminates. The influence of coupling decreased from a large effect in the general unsymmetric laminate, to practically no effect in the quasi-isotropic laminate. For example, the torsional loading of the general unsymmetric laminate resulted in a radial displacement. The temperature change also caused a significant radial displacement to occur near the ends of the cylinder. On the other hand, the more conventional unsymmetric laminate and the quasi-isotropic cylinder did not deform radially when subjected to a torsional load. From the results obtained, it is clear the degree of elastic coupling can be controlled and indeed designed into a cylinder, the degree and character of the coupling being dictated by the application
Neutrino Physics and Nuclear Axial Two-Body Interactions
We consider the counter-term describing isoscalar axial two-body currents in
the nucleon-nucleon interaction, L1A, in the effective field theory approach.
We determine this quantity using the solar neutrino data. We investigate the
variation of L1A when different sets of data are used.Comment: 8 pages with 4 figures. To be published in the Proceedings of the
Conference "Blueprints For The Nucleus: From First Principles to Collective
Motion" held at Feza Gursey Institute, Istanbul, Turkey; May 17 -22, 200
Lepton-nucleon interactions at the next-to-the-leading order
Next-to-Leading-Order (NLO) effects play a crucial role in tests of the
Standard Model (SM), and require careful theoretical evaluation. Electroweak
physics, which has just entered the precision age, is an excellent place to
search for new physics, but also requires considerable theoretical input. We
show how we applied computational packages such as FeynArts, FormCalc, Form and
LoopTools for the evaluation of one-loop electroweak and hadronic radiative
corrections
Tidal influence on self-potential measurements
DJM was supported by NERC CASE studentship NE/I018417/1. The authors would also like to thank Southern Water for access to the borehole at Saltdean. Atkins Global and Southern Water are thanked for funding installation of the equipment and for additional funding under the NERC studentship. The laboratory components of this work were carried out in the TOTAL Reservoir Physics Laboratory at Imperial College London and their support is gratefully acknowledged. Jackson acknowledges partial support from TOTAL under the TOTAL Chairs programme. The data supporting the conclusions of this work are available through the corresponding author.Peer reviewedPublisher PD
Development of polyisocyanurate pour foam formulation for space shuttle external tank thermal protection system
Four commercially available polyisocyanurate polyurethane spray-foam insulation formulations are used to coat the external tank of the space shuttle. There are several problems associated with these formulations. For example, some do not perform well as pourable closeout/repair systems. Some do not perform well at cryogenic temperatures (poor adhesion to aluminum at liquid nitrogen temperatures). Their thermal stability at elevated temperatures is not adequate. A major defect in all the systems is the lack of detailed chemical information. The formulations are simply supplied to NASA and Martin Marietta, the primary contractor, as components; Part A (isocyanate) and Part B (poly(s) and additives). Because of the lack of chemical information the performance behavior data for the current system, NASA sought the development of a non-proprietary room temperature curable foam insulation. Requirements for the developed system were that it should exhibit equal or better thermal stability both at elevated and cryogenic temperatures with better adhesion to aluminum as compared to the current system. Several formulations were developed that met these requirements, i.e., thermal stability, good pourability, and good bonding to aluminum
Not All Antibodies Are Created Equal: Factors That Influence Antibody Mediated Rejection.
Consistent with Dr. Paul Terasaki's "humoral theory of rejection" numerous studies have shown that HLA antibodies can cause acute and chronic antibody mediated rejection (AMR) and decreased graft survival. New evidence also supports a role for antibodies to non-HLA antigens in AMR and allograft injury. Despite the remarkable efforts by leaders in the field who pioneered single antigen bead technology for detection of donor specific antibodies, a considerable amount of work is still needed to better define the antibody attributes that are associated with AMR pathology. This review highlights what is currently known about the clinical context of pre and posttransplant antibodies, antibody characteristics that influence AMR, and the paths after donor specific antibody production (no rejection, subclinical rejection, and clinical dysfunction with AMR)
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