4,198 research outputs found
Significance of arming, potentiating and blocking factors as correlates the tumour-host interaction in the hamster SV40 system.
The study of blocking factors requires in vitro assay of cell mediated immunity that parallels the in vivo response. By microcytotoxicity testing, progressor and immune peripheral blood lymphocytes caused significant target cell reduction. The cytotoxicity was specific as no cytotoxic effect was detected against unrelated normal as well as a malignant target cell lines. No anti-tumour effect was noted when progressor peripheral blood lymphocytes were evaluated in the Winn assay. In marked contrast, immune peripheral blood lymphocytes were capable of preventing tumour growth in the Winn assay. Furthermore, hamsters repeatedly immunized with irradiated SV40 tumour cells could resist a live cell challenge. Thus immune peripheral blood lymphocytes were chosen as the effector population to evaluate the abrogation ability of serum in the microcytotoxicity assay
Investigation of the fundamental constants stability based on the reactor Oklo burn-up analysis
The burn-up for SC56-1472 sample of the natural Oklo reactor zone 3 was
calculated using the modern Monte Carlo codes. We reconstructed the neutron
spectrum in the core by means of the isotope ratios: Sm/Sm and
Lu/Lu. These ratios unambiguously determine the spectrum index
and core temperature. The effective neutron absorption cross section of
Sm calculated using this spectrum was compared with experimental one.
The disagreement between these two values allows to limit a possible shift of
the low laying resonance of Sm even more . Then, these limits were
converted to the limits for the change of the fine structure constant .
We found that for the rate of change the inequality is fulfilled, which is of the next
higher order than our previous limit.Comment: 16 pages, 7 figure
A Time Variation of Proton-Electron Mass Ratio and Grand Unification
Astrophysical observations indicate a time variation of the proton-electron
mass ratio and of the fine-structure constant. We discuss this phenomenon in
models of Grand Unification. In these models a time variation of the
fine-structure constant and of the proton mass are expected, if either the
unified coupling constant or the scale of unification changes, or both change.
We discuss in particular the change of the proton mass. Experiments in Quantum
Optics could be done to check these ideas.Comment: 5 page
Slow roll inflation in the presence of a dark energy coupling
In models of coupled dark energy, in which a dark energy scalar field couples to other matter components, it is natural to expect a coupling to the inflaton as well. We explore the consequences of such a coupling in the context of single-field slow-roll inflation. Assuming an exponential potential for the quintessence field we show that the coupling to the inflaton causes the quintessence field to be attracted toward the minimum of the effective potential. If the coupling is large enough, the field is heavy and is located at the minimum. We show how this affects the expansion rate and the slow-roll of the inflaton field, and therefore the primordial perturbations generated during inflation. We further show that the coupling has an important impact on the processes of reheating and preheating
We Could, but Should We? Ethical Considerations for Providing Access to GeoCities and Other Historical Digital Collections
We live in an era in which the ways that we can make sense of our past are evolving as more artifacts from that past become digital. At the same time, the responsibilities of traditional gatekeepers who have negotiated the ethics of historical data collection and use, such as librarians and archivists, are increasingly being sidelined by the system builders who decide whether and how to provide access to historical digital collections, often without sufficient reflection on the ethical issues at hand. It is our aim to better prepare system builders to grapple with these issues. This paper focuses discussions around one such digital collection from the dawn of the web, asking what sorts of analyses can and should be conducted on archival copies of the GeoCities web hosting platform that dates to 1994.This research was supported by the Natural Sciences and Engineering Research Council of Canada, the Social Sciences and Humanities Research Council of Canada, the US National Science Foundation (grants 1618695 and 1704369), the Andrew W. Mellon Foundation, Start Smart Labs, and Compute Canada
The JCMT 12CO(3-2) Survey of the Cygnus X Region: I. A Pathfinder
Cygnus X is one of the most complex areas in the sky. This complicates
interpretation, but also creates the opportunity to investigate accretion into
molecular clouds and many subsequent stages of star formation, all within one
small field of view. Understanding large complexes like Cygnus X is the key to
understanding the dominant role that massive star complexes play in galaxies
across the Universe.
The main goal of this study is to establish feasibility of a high-resolution
CO survey of the entire Cygnus X region by observing part of it as a
Pathfinder, and to evaluate the survey as a tool for investigating the
star-formation process.
A 2x4 degree area of the Cygnus X region has been mapped in the 12CO(3-2)
line at an angular resolution of 15" and a velocity resolution of ~0.4km/s
using HARP-B and ACSIS on the James Clerk Maxwell Telescope. The star formation
process is heavily connected to the life-cycle of the molecular material in the
interstellar medium. The high critical density of the 12CO(3-2) transition
reveals clouds in key stages of molecule formation, and shows processes that
turn a molecular cloud into a star.
We observed ~15% of Cygnus X, and demonstrated that a full survey would be
feasible and rewarding. We detected three distinct layers of 12CO(3-2)
emission, related to the Cygnus Rift (500-800 pc), to W75N (1-1.8 kpc), and to
DR21 (1.5-2.5 kpc). Within the Cygnus Rift, HI self-absorption features are
tightly correlated with faint diffuse CO emission, while HISA features in the
DR21 layer are mostly unrelated to any CO emission. 47 molecular outflows were
detected in the Pathfinder, 27 of them previously unknown. Sequentially
triggered star formation is a widespread phenomenon.Comment: 18 pages, 13 figures, accepted for publication in Astronomy &
Astrophysic
The Indian family on UK reality television: Convivial culture in salient contexts
This is the author's accepted manuscript. The final published article is available from the link below, copyright 2012 @ the author.This article demonstrates how The Family (2009), a fly-on-the wall UK reality series about a British Indian family, facilitates both current public service broadcasting requirements and mass audience appeal. From a critical cultural studies perspective, the author examines the journalistic and viewer responses to the series where authenticity, universality, and comedy emerge as major themes. Textual analysis of the racialized screen representations also helps locate the series within the contexts of contested multiculturalism, genre developments in reality television and public service broadcasting. Paul Gilroyâs concept of convivial culture is used as a frame in understanding how meanings of the series are produced within a South Asian popular representational space. The author suggests that the social comedy taxonomy is a prerequisite for the making of this particular observational documentary. Further, the popular (comedic) mode of conviviality on which the series depends is both expedient and necessary within the various sociopolitical contexts outlined
Processing Multi-Spectral Scanning Electron Microscopy Images for Quantitative Microfabric Analysis
Multi-spectral image analysis is a powerful method to characterise quantitatively the mineralogy and microfabric of soils, sediments, and other particulate materials. Backscattered scanning electron microscope (SEM) images of polished, resin-impregnated samples are grouped with the corresponding X-ray elemental maps using classification methods commonly used in remote sensing. However, the resulting mineral-segmented images require processing to render them suitable for quantification. In the past, this has been done subjectively and interactively, but the new objective methods described in this paper largely eliminate this subjectivity. An intensity gradient magnitude image of the original backscattered electron image is used as the basis of an interactive erosion and dilation sequence to generate skeleton outlines defining the edges of the mineral grains. The areas defined within the skeleton areas are then classified as a particular mineral according to the predominant feature in the corresponding mineral-segmented image. Subsequent processing tackles the problems of \u27holes\u27 defined by the skeleton outlines, and the over-segmentation associated with certain classes of mineral grain. Further methods to deal with particles made up of more than one mineral are considered.
The matrix and porosity information is recombined to generate an image suitable for analysis using feature size statistics or general orientation analysis. The techniques described can be combined to permit batch processing of images. Applications of the techniques are illustrated on a soil from the East Anglian Breckland
Transcriptomic profiling of 39 commonly-used neuroblastoma cell lines
Neuroblastoma cell lines are an important and cost-effective model used to study oncogenic drivers of the disease. While many of these cell lines have been previously characterized with SNP, methylation, and/or mRNA expression microarrays, there has not been an effort to comprehensively sequence these cell lines. Here, we present raw whole transcriptome data generated by RNA sequencing of 39 commonly-used neuroblastoma cell lines. These data can be used to perform differential expression analysis based on a genetic aberration or phenotype in neuroblastoma (e.g., MYCN ampliïŹcation status, ALK mutation status, chromosome arm 1p, 11q and/or 17q status, sensitivity to pharmacologic perturbation). Additionally, we designed this experiment to enable structural variant and/or long-noncoding RNA analysis across these cell lines. Finally, as more DNase/ATAC and histone/transcription factor ChIP sequencing is performed in these cell lines, our RNA-Seq data will be an important complement to inform transcriptional targets as well as regulatory (enhancer or repressor) elements in neuroblastoma
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