14,827 research outputs found
Why can't every year be a National Year of Reading? An evaluation of the NYR in Yorkshire
An evaluation of the National Year of Reading in Yorkshire was conducted by Leeds Metropolitan University in response to a brief from Museums, Libraries and Archives, Yorkshire. This paper outlines the development and planning of phase one of this small scale qualitative research project and the analysis of the initial results which looks at the impact of NYR on the organisations that delivered the campaign and their work with target groups. The Generic Social Outcomes and the National Indicators were used to develop a theoretical framework. Data were gathered via in depth interviews and focus groups with NYR steering group partners in Calderdale and North Lincolnshire, selected as the two case study authorities. The use of MAXQDA computer-assisted qualitative data analysis software (CAQDAS) enabled data and coding structures to be stored and will facilitate comparison in this longitudinal study. This evaluation will provide material that local library authorities can use for advocacy with a range of audiences including local and central government
Next-to-Leading Order Corrections to Single Top Quark Production and Decay at the Tevatron: 2. -channel Process
We present a study of the -channel mode of single top quark production at
the upgraded Tevatron collider, including the next-to-leading order
(NLO) QCD corrections to the production and the decay of a single top quark.
The narrow width approximation was adopted in order to preserve the spin of the
top quark in its production and decay. We discuss the effects of different
contributions on the inclusive cross section as well as various
kinematic distributions after imposing the relevant cuts to select -channel
single top signal events.Comment: 46 pages, 47 figures. One typo in LaTeX source file is correcte
A new approach to mass spectrometer measurements of thermospheric density
The gas sampling problem in satellite and high velocity probes was investigated by applying the theory of a drifting Maxwellian gas. A lens system using a free stream ion source was developed and experimentally evaluated over the pressure range of 0.00001 to 0.01 N/m sq (approx. 10 to the minus 7th power to 0.0001 torr). The source has high beam transparency, which minimizes gas-surface collisions within, or near, the ionization volume. It is shown that for high ion energy (60 eV), the extracted ion beam has an on-axis energy spread of less than 4 eV, and that 90 percent of the ions are within 2.5 deg of the beam axis. It is concluded that the molecular beam mass spectrometer concept, developed for gas density measurements in the upper atmosphere, substantially reduces gas-surface scattering and gas-surface reactions in the sample, and preserves the integrity of the gas sample during the analysis process. Studies show that both the Scout and Delta launch vehicles have adequate volume, control, velocity, and data acquisition capability necessary to obtain thermospheric number density in real time
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Absence of an embryonic stem cell DNA methylation signature in human cancer.
BackgroundDifferentiated cells that arise from stem cells in early development contain DNA methylation features that provide a memory trace of their fetal cell origin (FCO). The FCO signature was developed to estimate the proportion of cells in a mixture of cell types that are of fetal origin and are reminiscent of embryonic stem cell lineage. Here we implemented the FCO signature estimation method to compare the fraction of cells with the FCO signature in tumor tissues and their corresponding nontumor normal tissues.MethodsWe applied our FCO algorithm to discovery data sets obtained from The Cancer Genome Atlas (TCGA) and replication data sets obtained from the Gene Expression Omnibus (GEO) data repository. Wilcoxon rank sum tests, linear regression models with adjustments for potential confounders and non-parametric randomization-based tests were used to test the association of FCO proportion between tumor tissues and nontumor normal tissues. P-values of < 0.05 were considered statistically significant.ResultsAcross 20 different tumor types we observed a consistently lower FCO signature in tumor tissues compared with nontumor normal tissues, with 18 observed to have significantly lower FCO fractions in tumor tissue (total n = 6,795 tumor, n = 922 nontumor, P < 0.05). We replicated our findings in 15 tumor types using data from independent subjects in 15 publicly available data sets (total n = 740 tumor, n = 424 nontumor, P < 0.05).ConclusionsThe results suggest that cancer development itself is substantially devoid of recapitulation of normal embryologic processes. Our results emphasize the distinction between DNA methylation in normal tightly regulated stem cell driven differentiation and cancer stem cell reprogramming that involves altered methylation in the service of great cell heterogeneity and plasticity
Time Dependent Clustering Analysis of the Second BATSE Gamma-Ray Burst Catalog
A time dependent two-point correlation-function analysis of the BATSE 2B
catalog finds no evidence of burst repetition. As part of this analysis, we
discuss the effects of sky exposure on the observability of burst repetition
and present the equation describing the signature of burst repetition in the
data. For a model of all burst repetition from a source occurring in less than
five days we derive upper limits on the number of bursts in the catalog from
repeaters and model-dependent upper limits on the fraction of burst sources
that produce multiple outbursts.Comment: To appear in the Astrophysical Journal Letters, uuencoded compressed
PostScript, 11 pages with 4 embedded figure
Radiocarbon dates from the Oxford AMS system: archaeometry datelist 35
This is the 35th list of AMS radiocarbon determinations measured at the Oxford Radiocarbon Accelerator Unit (ORAU). Amongst some of the sites included here are the latest series of determinations from the key sites of Abydos, El MirĂłn, Ban Chiang, Grotte de Pigeons (Taforalt), Alepotrypa and Oberkassel, as well as others dating to the Palaeolithic, Mesolithic and later periods. Comments on the significance of the results are provided by the submitters of the material
American skullcap (Scutellaria lateriflora): an ancient remedy for today’s anxiety?
Anxiety is a common but potentially serious disorder as it can lead to somatic and social dysfunction. Orthodox anxiolytics are associated with unpleasant side-effects and dependency. American skullcap (Scutellaria lateriflora) is a popular herb in traditional medicine systems and the western materia medica for anxiety and related disorders. Preliminary clinical and in vitro research provides encouraging support for its potential as a safe, well-tolerated and effective alternative
Synthesis, Structure and Properties of Tetragonal Sr2M3As2O2 (M3 = Mn3, Mn2Cu and MnZn2) Compounds Containing Alternating CuO2-Type and FeAs-Type Layers
Polycrystalline samples of Sr2Mn2CuAs2O2, Sr2Mn3As2O2, and Sr2Zn2MnAs2O2 were
synthesized. Their temperature- and applied magnetic field-dependent
structural, transport, thermal, and magnetic properties were characterized by
means of x-ray and neutron diffraction, electrical resistivity rho, heat
capacity, magnetization and magnetic susceptibility measurements. These
compounds have a body-centered-tetragonal crystal structure (space group
I4/mmm) that consists of MO2 (M = Zn and/or Mn) oxide layers similar to the
CuO2 layers in high superconducting transition temperature Tc cuprate
superconductors, and intermetallic MAs (M = Cu and/or Mn) layers similar to the
FeAs layers in high-Tc pnictides. These two types of layers alternate along the
crystallographic c-axis and are separated by Sr atoms. The site occupancies of
Mn, Cu and Zn were studied using Rietveld refinements of x-ray and neutron
powder diffraction data. The temperature dependences of rho suggest metallic
character for Sr2Mn2CuAs2O2 and semiconducting character for Sr2Mn3As2O2 and
Sr2Zn2MnAs2O2. Sr2Mn2CuAs2O2 is inferred to be a ferrimagnet with a Curie
temperature TC = 95(1) K. Remarkably, we find that the magnetic ground state
structure changes from a G-type antiferromagnetic structure in Sr2Mn3As2O2 to
an A-type ferrimagnetic structure in Sr2Mn2CuAs2O2 in which the Mn ions in each
layer are ferromagnetically aligned, but are antiferromagnetically aligned
between layers.Comment: 18 pages, 16 figures, 6 tables; submitted to Phys. Rev.
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