1,334 research outputs found
Recommended from our members
The Telemetry Agile Manufacturing Effort
The Telemetry Agile Manufacturing Effort (TAME) is an agile enterprising demonstration sponsored by the US Department of Energy (DOE). The project experimented with new approaches to product realization and assessed their impacts on performance, cost, flow time, and agility. The purpose of the project was to design the electrical and mechanical features of an integrated telemetry processor, establish the manufacturing processes, and produce an initial production lot of two to six units. This paper outlines the major methodologies utilized by the TAME, describes the accomplishments that can be attributed to each methodology, and finally, examines the lessons learned and explores the opportunities for improvement associated with the overall effort. The areas for improvement are discussed relative to an ideal vision of the future for agile enterprises. By the end of the experiment, the TAME reduced production flow time by approximately 50% and life cycle cost by more than 30%. Product performance was improved compared with conventional DOE production approaches
Gauge Invariant Variational Approach with Fermions: the Schwinger Model
We extend the gauge invariant variational approach of Phys. Rev. D52 (1995)
3719, hep-th/9408081, to theories with fermions. As the simplest example we
consider the massless Schwinger model in 1+1 dimensions. We show that in this
solvable model the simple variational calculation gives exact results.Comment: 14 pages, 1 figur
QCD Phase Transition with Strange Quark in Wilson Formalism for Fermions
The nature of QCD phase transition is studied with massless up and down
quarks and a light strange quark, using the Wilson formalism for quarks on a
lattice with the temporal direction extension . We find that the phase
transition is first order in the cases of both about 150 MeV and 400 MeV for
the strange quark mass. These results together with those for three degenerate
quarks suggest that QCD phase transition in nature is first order.Comment: uuencoded compressed tar file, LaTeX, 13 pages, 9 figures, Minor
errors for quoting references are corrected and a reference is adde
Nature of singularity formed by the gravitational collapse in Husain space-time with electromagnetic field and scalar field
In this work, we have investigated the outcome of gravitational collapse in
Husain space-time in the presence of electro-magnetic and a scalar field with
potential. In order to study the nature of the singularity, global behavior of
radial null geodesics have been taken into account. The nature of singularities
formed has been thoroughly studied for all possible variations of the
parameters. These choices of parameters has been presented in tabular form in
various dimensions. It is seen that irrespective of whatever values of the
parameters chosen, the collapse always results in a naked singularity in all
dimensions. There is less possibility of formation of a black hole. Hence this
work is a significant counterexample of the cosmic censorship hypothesis.Comment: 9 pages, 19 figure
Rapid modification of the bone microenvironment following short-term treatment with Cabozantinib in vivo
Introduction: Bone metastasis remains incurable with treatment restricted to palliative care. Cabozantinib (CBZ) is
targeted against multiple receptor tyrosine kinases involved in tumour pathobiology, including hepatocyte growth
factor receptor (MET) and vascular endothelial growth factor receptor 2 (VEGFR-2). CBZ has demonstrated clinical
activity in advanced prostate cancer with resolution of lesions visible on bone scans, implicating a potential role of
the bone microenvironment as a mediator of CBZ effects. We characterised the effects of short-term administration
of CBZ on bone in a range of in vivo models to determine how CBZ affects bone in the absence of tumour.
Methods: Studies were performed in a variety of in vivo models including male and female BALB/c nude mice (age 6–
17-weeks). Animals received CBZ (30 mg/kg, 5× weekly) or sterile H2O control for 5 or 10 days. Effects on bone integrity
(μCT), bone cell activity (PINP, TRAP ELISA), osteoblast and osteoclast number/mm trabecular bone surface,
area of epiphyseal growth plate cartilage, megakaryocyte numbers and bone marrow composition were assessed.
Effects of longer-term treatment (15-day & 6-week administration) were assessed in male NOD/SCID and beige
SCID mice.
Results: CBZ treatment had significant effects on the bone microenvironment, including reduced osteoclast and increased
osteoblast numbers compared to control. Trabecular bone structure was altered after 8 administrations. A
significant elongation of the epiphyseal growth plate, in particular the hypertrophic chondrocyte zone, was observed
in all CBZ treated animals irrespective of administration schedule. Both male and female BALB/c nude mice had increased
megakaryocyte numbers/mm2 tissue after 10-day CBZ treatment, in addition to vascular ectasia, reduced
bone marrow cellularity and extravasation of red blood cells into the extra-vascular bone marrow. All CBZinduced
effects were transient and rapidly lost following cessation of treatment.
Conclusion: Short-term administration of CBZ induces rapid, reversible effects on the bone microenvironmentin vivo
highlighting a potential role in mediating treatment responses
Terminal n-linked galactose is the primary receptor for adeno-associated virus
Sialylated glycans serve as cell surface attachment factors for a broad range of pathogens. We report an atypical example, where desialylation increases cell surface binding and infectivity of adeno-associated virus (AAV) serotype 9, a human parvovirus isolate. Enzymatic removal of sialic acid, but not heparan sulfate or chondroitin sulfate, increased AAV9 transduction regardless of cell type. Viral binding and transduction assays on mutant Chinese hamster ovary (CHO) cell lines defective in various stages of glycan chain synthesis revealed a potential role for core glycan residues under sialic acid in AAV9 transduction. Treatment with chemical inhibitors of glycosylation and competitive inhibition studies with different lectins suggest that N-linked glycans with terminal galactosyl residues facilitate cell surface binding and transduction by AAV9. In corollary, resialylation of galactosylated glycans on the sialic acid-deficient CHO Lec2 cell line with different sialyltransferases partially blocked AAV9 transduction. Quantitative analysis of AAV9 binding to parental, sialidase-treated or sialic acid-deficient mutant CHO cells revealed a 3-15-fold increase in relative binding potential of AAV9 particles upon desialylation. Finally, pretreatment of well differentiated human airway epithelial cultures and intranasal instillation of recombinant sialidase in murine airways enhanced transduction efficiency of AAV9 by > 1 order of magnitude. Taken together, the studies described herein provide a molecular basis for low infectivity of AAV9 in vitro and a biochemical strategy to enhance gene transfer by AAV9 vectors in general
Cosmic String Cusps with Small-Scale Structure: Their Forms and Gravitational Waveforms
We present a method for the introduction of small-scale structure into
strings constructed from products of rotation matrices. We use this method to
illustrate a range of possibilities for the shape of cusps that depends on the
properties of the small-scale structure. We further argue that the presence of
structure at cusps under most circumstances leads to the formation of loops at
the size of the smallest scales. On the other hand we show that the
gravitational waveform of a cusp remains generally unchanged; the primary
effect of small-scale structure is to smooth out the sharp waveform emitted in
the direction of cusp motion.Comment: RevTeX, 8 pages. Replaced with version accepted for publication by
PR
Anisotropy of exchange stiffness and its effect on the properties of magnets
Using the spin-spiral formulation of the tight-binding linear muffin-tin
orbital method, the principal components of the exchange stiffness tensor are
calculated for typical hard magnets including tetragonal CoPt-type and
hexagonal YCo5 alloys. The exchange stiffness is strongly anisotropic in all
studied alloys. This anisotropy makes the domain wall surface tension
anisotropic. Competition between this anisotropic surface tension and
magnetostatic energy controls the formation and dynamics of nanoscale domain
structures in hard magnets. Anisotropic domain wall bending is described in
detail from the general point of view and with application to cellular Sm-Co
magnets. It is shown that the repulsive cell-boundary pinning mechanism in
these magnets is feasible only due to the anisotropic exchange stiffness if
suitably oriented initial pinning centers are available. In polytwinned
CoPt-type magnets the exchange stiffness anisotropy controls the orientation of
macrodomain wall segments. These segments may reorient both statically during
microstructural coarsening and dynamically during the macrodomain wall
splitting in external field. Reorientation of segments may facilitate their
pinning at antiphase boundaries.Comment: 9 pages, 2 figures, revtex4; to be published in J. Magn. Magn Mate
Multiplicative renormalizability and quark propagator
The renormalized Dyson-Schwinger equation for the quark propagator is
studied, in Landau gauge, in a novel truncation which preserves multiplicative
renormalizability. The renormalization constants are formally eliminated from
the integral equations, and the running coupling explicitly enters the kernels
of the new equations. To construct a truncation which preserves multiplicative
renormalizability, and reproduces the correct leading order perturbative
behavior, non-trivial cancellations involving the full quark-gluon vertex are
assumed in the quark self-energy loop. A model for the running coupling is
introduced, with infrared fixed point in agreement with previous
Dyson-Schwinger studies of the gauge sector, and with correct logarithmic tail.
Dynamical chiral symmetry breaking is investigated, and the generated quark
mass is of the order of the extension of the infrared plateau of the coupling,
and about three times larger than in the Abelian approximation, which violates
multiplicative renormalizability. The generated scale is of the right size for
hadronic phenomenology, without requiring an infrared enhancement of the
running coupling.Comment: 17 pages; minor corrections, comparison to lattice results added;
accepted for publication in Phys. Rev.
Earthworm records and habitat associations in the British Isles
The National Earthworm Recording Scheme (NERS) is the most comprehensive national database of earthworm species occurrence records for the British Isles, and possibly for any individual country in the world. Utilising the NERS database, we sought to update the current knowledge of earthworm species occurrences in the UK, Ireland and Channel Islands; identify species-specific habitat and microhabitat associations; reveal any biases and complementarities between amateur naturalist and research-related earthworm record collection; and inform how future earthworm sampling can be better focussed to improve our knowledge of earthworm ecology. We found that the most commonly occurring earthworm species were present in farmland and woodland, and recovered via soil pit sampling, the most common habitat-sampling protocol combinations. However, several earthworm species showed specificity to alternative habitats (such as trees, wetlands, and compost), and association with microhabitat (non-soil) sampling. There were clear disparities between scientific researchers and amateur naturalist recorders in terms of habitat types visited and sampling protocols/microhabitats used in the collection of earthworm records. Most importantly, we found that earthworm species currently considered to be nationally ‘rare’ in the British Isles are significantly associated with the most under-represented habitat-protocol/microhabitat combinations (forest deadwood and other microhabitats, in addition to scrubland, wetland and heathland habitats), and thus may not be rare, only under-sampled. We therefore encourage earthworm researchers and recorders to give greater attention to these situations, to gain new insights into these earthworm species' ecologies and distributions. Finally, we would like to promote the establishment of earthworm recording schemes in other countries, to enable national and global collaborative monitoring of earthworm responses to environmental change
- …