W+W- Hadronic Decay Properties

Recent measurements of the properties of W+W- events produced in e+e- collisions at Ecm=183 GeV at LEP are reviewed. The data are used to investigate the predicted effects of final state interactions, specifically "colour reconnection".Comment: 6 pages, 7 figures. To appear in the "Proceedings of the XXIX International Conference on High Energy Physics", Vancouver, CA, 23-29 July 199

Payload/burned-out motor case separation system Patent

Payload/spent rocket engine case separation syste

Experimental aspects of colour reconnection

This report summarises experimental aspects of the phenomena of colour reconnection in W+W- production, concentrating on charged multiplicity and event shapes, which were carried out as part of the Phenomenology Workshop on LEP2 Physics, Oxford, Physics Department and Keble College, 14-18 April, 1997. The work includes new estimates of the systematic uncertainty which may be attributed to colour reconnection effects in experimental measurements of Mw.Comment: 10 pages, 4 figures. To be published in proceedings of Phenomenology Workshop on LEP2 Physics, Oxford 14-18 April 199

A new thermal vacuum facility at the Martin Marietta Waterton plant

A new thermal-vacuum facility has been recently completed at the Martin Marietta Waterton plant near Denver, Colorado. The facility was designed, fabricated, installed, and tested as a turn-key project by Pitt-Des Moines Inc. and CVI Inc. The chamber has a 5.49 M by 6.10 M (18 ft by 20 ft) flat floor and a half-cylindrical roof with a diameter of 5.49 M (18 ft). Both ends of the chamber have full cross section doors, with one equipped with translating motors for horizontal motion. The chamber is provided with four 0.91 M (36 inches) cryopumps to obtain an ultimate pressure of 9 x 10(exp -8) Torr (Clean-Dry-Empty). The thermal shroud is designed to operate at a maximum of -179 C (-290 F) with an internal heat input of 316 MJ/Hr (300,000 BTU/Hr) using liquid nitrogen. The shroud is also designed to operate at any temperature between -156 C (-250 F) and 121 C (+250 F) using gaseous nitrogen, and heat or cool at a rate of 1.1 C (2 F) per minute

Gluon Correlators in the Kogan-Kovner Model

The Lorentz-invariant gluon correlation functions, corresponding to scalar and pseudo-scalar glueballs, are calculated for Kogan's and Kovner's variational ansatz for the pure SU(N) Yang-Mills wavefunctional. One expects that only one dynamical mass scale should be present in QCD; the ansatz generates the expected scale for both glueballs, as well as an additional scale for the scalar glueball. The additional mass scale must therefore vanish, or be close to the expected one. This is shown to constrain the nature of the phase transition in the Kogan-Kovner ansatz.Comment: 9 pages, no figure

Human platelet activation by Escherichia coli: roles for FcγRIIA and integrin αIIbβ3

Gram-negative Escherichia coli cause diseases such as sepsis and hemolytic uremic syndrome in which thrombotic disorders can be found. Direct platelet–bacterium interactions might contribute to some of these conditions; however, mechanisms of human platelet activation by E. coli leading to thrombus formation are poorly understood. While the IgG receptor FcγRIIA has a key role in platelet response to various Gram-positive species, its role in activation to Gram-negative bacteria is poorly defined. This study aimed to investigate the molecular mechanisms of human platelet activation by E. coli, including the potential role of FcγRIIA. Using light-transmission aggregometry, measurements of ATP release and tyrosine-phosphorylation, we investigated the ability of two E. coli clinical isolates to activate platelets in plasma, in the presence or absence of specific receptors and signaling inhibitors. Aggregation assays with washed platelets supplemented with IgGs were performed to evaluate the requirement of this plasma component in activation. We found a critical role for the immune receptor FcγRIIA, αIIbβ3, and Src and Syk tyrosine kinases in platelet activation in response to E. coli. IgG and αIIbβ3 engagement was required for FcγRIIA activation. Moreover, feedback mediators adenosine 5’-diphosphate (ADP) and thromboxane A₂ (TxA₂) were essential for platelet aggregation. These findings suggest that human platelet responses to E. coli isolates are similar to those induced by Gram-positive organisms. Our observations support the existence of a central FcγRIIA-mediated pathway by which human platelets respond to both Gram-negative and Gram-positive bacteria

The shape of primordial non-Gaussianity and the CMB bispectrum

We present a set of formalisms for comparing, evolving and constraining primordial non-Gaussian models through the CMB bispectrum. We describe improved methods for efficient computation of the full CMB bispectrum for any general (non-separable) primordial bispectrum, incorporating a flat sky approximation and a new cubic interpolation. We review all the primordial non-Gaussian models in the present literature and calculate the CMB bispectrum up to l <2000 for each different model. This allows us to determine the observational independence of these models by calculating the cross-correlation of their CMB bispectra. We are able to identify several distinct classes of primordial shapes - including equilateral, local, warm, flat and feature (non-scale invariant) - which should be distinguishable given a significant detection of CMB non-Gaussianity. We demonstrate that a simple shape correlator provides a fast and reliable method for determining whether or not CMB shapes are well correlated. We use an eigenmode decomposition of the primordial shape to characterise and understand model independence. Finally, we advocate a standardised normalisation method for $f_{NL}$ based on the shape autocorrelator, so that observational limits and errors can be consistently compared for different models.Comment: 32 pages, 20 figure

Collagen-hyaluronic acid scaffolds for adipose tissue engineering.

Three-dimensional (3-D) in vitro models of the mammary gland require a scaffold matrix that supports the development of adipose stroma within a robust freely permeable matrix. 3-D porous collagen-hyaluronic acid (HA: 7.5% and 15%) scaffolds were produced by controlled freeze-drying technique and crosslinking with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride. All scaffolds displayed uniform, interconnected pore structure (total porosity approximately 85%). Physical and chemical analysis showed no signs of collagen denaturation during the formation process. The values of thermal characteristics indicated that crosslinking occurred and that its efficiency was enhanced by the presence of HA. Although the crosslinking reduced the swelling of the strut material in water, the collagen-HA matrix as a whole tended to swell more and show higher dissolution resistance than pure collagen samples. The compressive modulus and elastic collapse stress were higher for collagen-HA composites. All the scaffolds were shown to support the proliferation and differentiation 3T3-L1 preadipocytes while collagen-HA samples maintained a significantly increased proportion of cycling cells (Ki-67+). Furthermore, collagen-HA composites displayed significantly raised Adipsin gene expression with adipogenic culture supplementation for 8 days vs. control conditions. These results indicate that collagen-HA scaffolds may offer robust, freely permeable 3-D matrices that enhance mammary stromal tissue development in vitro.This was supported by the Biotechnology and Biological Sciences Research Council