3,335 research outputs found
Modeling atmospheric effects of the September 1859 Solar Flare
We have modeled atmospheric effects, especially ozone depletion, due to a
solar proton event which probably accompanied the extreme magnetic storm of 1-2
September 1859. We use an inferred proton fluence for this event as estimated
from nitrate levels in Greenland ice cores. We present results showing
production of odd nitrogen compounds and their impact on ozone. We also compute
rainout of nitrate in our model and compare to values from ice core data.Comment: Revised version including improved figures; Accepted for publication
in Geophys. Res. Lett, chosen to be highlighted by AG
Labour Market Policy and the Reallocation of Labour Across Sectors
This paper investigates the extent of labour market allocation across broad industrial sectors in the transition of economies of Eastern Europe since 1989. It offers various measures of the magnitude of labour misallocation and of the speed and efficiency of reallocation during the first half of the 1980s. It compares the performance of the economies of Eastern Europe with one another and with two Southern European economies, Greece and Portugal, which have also been experiencing substantial economic change. Contrary to much a pirori theorising, the paper finds no correlation between unemployment and the speed or effectiveness of labour market reallocation. The authors argue that the analysis in the paper strengthens the case for an active as against a passive approach to labour market policy.
The ChIP-seq-defined networks of Bcl-3 gene binding support its required role in skeletal muscle atrophy
NF-kappaB transcriptional activation is required for skeletal muscle disuse atrophy. We are continuing to study how the activation of NF-kB regulates the genes that encode the protein products that cause atrophy. Using ChIP-sequencing we found that Bcl-3, an NF-kB transcriptional activator required for atrophy, binds to the promoters of a number of genes whose collective function describes two major aspects of muscle wasting. By means of bioinformatics analysis of ChIP-sequencing data we found Bcl-3 to be directing transcription networks of proteolysis and energy metabolism. The proteolytic arm of the Bcl-3 networks includes many E3 ligases associated with proteasomal protein degradation, including that of the N-end rule pathway. The metabolic arm appears to be involved in organizing the change from oxidative phosphorylation to glycolysis in atrophying muscle. For one gene, MuRF1, ChIP-sequencing data identified the location of Bcl-3 and p50 binding in the promoter region which directed the creation of deletant and base-substitution mutations of MuRF1 promoter constructs to determine the effect on gene transcription. The results provide the first direct confirmation that the NF-kB binding site is involved in the muscle unloading regulation of MuRF1. Finally, we have combined the ChIP-sequencing results with gene expression microarray data from unloaded muscle to map several direct targets of Bcl-3 that are transcription factors whose own targets describe a set of indirect targets for NF-kB in atrophy. ChIP-sequencing provides the first molecular explanation for the finding that Bcl3 knockout mice are resistant to disuse muscle atrophy. Mapping the transcriptional regulation of muscle atrophy requires an unbiased analysis of the whole genome, which we show is now possible with ChIP-sequencing.R01 AR041705 - NIAMS NIH HHS; R01 AR060217 - NIAMS NIH HHS; AR041705 - NIAMS NIH HHS; AR060217 - NIAMS NIH HH
A key role for leukemia inhibitory factor in C26 cancer cachexia
Cachexia is an exacerbating event in many types of cancer that is strongly associated with a poor prognosis. We have identified cytokine, signaling, and transcription factors that are required for cachexia in the mouse C26 colon carcinoma model of cancer. C2C12 myotubes treated with conditioned medium from C26 cancer cells induced atrophy and activated a STAT-dependent reporter gene but not reporter genes dependent on SMAD, FOXO, C/EBP, NF-κB, or AP-1. Of the gp130 family members IL-11, IL-6, oncostatin M (OSM), and leukemia inhibitory factor (LIF), only OSM and LIF were sufficient to activate the STAT reporter in myotubes. LIF was elevated in C26 conditioned medium (CM), but IL-6, OSM, TNFα, and myostatin were not. A LIF-blocking antibody abolished C26 CM-induced STAT reporter activation, STAT3 phosphorylation, and myotube atrophy but blocking antibodies to IL-6 or OSM did not. JAK2 inhibitors also blocked C26 CM-induced STAT reporter activation, STAT3 phosphorylation, and atrophy in myotubes. LIF at levels found in the C26 CM was sufficient for STAT reporter activation and atrophy in myotubes. In vivo, an increase in serum LIF preceded the increase in IL-6 in mice with C26 tumors. Overexpression of a dominant negative Stat3Cβ-EGFP gene in myotubes and in mouse muscle blocked the atrophy caused by C26 CM or C26 tumors, respectively. Taken together, these data support an important role of LIF-JAK2-STAT3 in C26 cachexia and point to a therapeutic approach for at least some types of cancer cachexia.R01 AR060217 - NIAMS NIH HHS; UL1 TR000157 - NCATS NIH HHS; UL1-TR000157 - NCATS NIH HHShttp://www.jbc.org/content/290/32/19976.full.pdf?sid=936d126d-814b-4f54-961d-0e98caa31314Published versio
Some sociological issues of live music performance
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.This research seeks to explore some of the sociological aspects of live music performance contexts. Research into the impact of contemporary mechanical means of musical reproduction has tended to divert attention away from the study of live performance. But the two major music traditions in western Industrial societies, Western European Art Music (WEAM) and Afro-American have their origins in the pre-recording era. Consideration of the development of their forms must take into account the changing contexts within which they were performed. The development of notation coupled with the emphasis on composition within WEAM facilitated the rise of an aesthetic autonomy for the 'work' giving rise to the most appropriate context for its performance: the purpose built modern concert hall celebrating in its rituals and relations a particular form of aesthetic address. The Afro-American tradition with its roots in disadvantaged and dominated black culture, and its emphasis on improvisation rather than formal composition, is less autonomous and is mediated more closely by the social relations of the contexts within which it is performed. Observations of various performance venues was undertaken, using a comparative frame developed from that used by Qureshi (1987) modified to take into account the comrnodification of music in an economic market. Observations were supported by interviews of jazz musicians about attitudes to performance and preferred settings. Two venues have been selected for detailed consideration: The Royal Festival Hall (a classical concert) and The Pontalba Cafe (a Jazz cafe in New Orleans). On the basis of the observations, the Interviews and consideration of the current literature, models of aesthetic ideology are constructed. It is suggested that there is an homology between 'fixed' forms and 'tight' contexts and 'flexible' forms and 'loose' contexts
Assessing the Genetic Status and Factors Leading to the Decline of the Roanoke Bass (Ambloplites Cavifrons)
Although numerous factors have led to the staggering declines in freshwater biodiversity throughout the United States and the world, habitat alteration and introduced species pose some of the greatest challenges to conservation efforts. Learning more about how these two factors lead to the decline of an endemic organism could help prevent the future loss of unique species and the premature conclusion of evolutionary trajectories. Roanoke bass (Ambloplites cavifrons) is a sport fish endemic to portions of the Roanoke, Chowan, Tar, and Neuse river basins of North Carolina and Virginia. This species has been in decline for many years, and it is believed that their continued existence is threatened by competition, and potentially hybridization and introgression with their introduced relative, the rock bass (Ambloplites rupestris). In addition to interactions with this invasive species, significant alteration of habitat is likely also a contributing factor in the decline of A. cavifrons. This study seeks to evaluate the relative contributions of these various factors to the decline of A. cavifrons. I utilized a combination of nuclear markers and mitochondrial sequence data to address the question of whether or not the two species are hybridizing in areas of syntopy, and furthermore to determine whether hybrids are fertile and able to breed back with the parental species. In addition, I identified extant populations of A. cavifrons throughout their historic range, and evaluated the genetic diversity of these populations and correlated these values with changes to the landscape in the form of alterations to watershed land use and the construction of impoundments. My results indicate large portions of the historic range of A. cavifrons no longer contain the species, and that remaining populations occur at the stream level and exist in isolation from one another. Obtaining this information allows for a better understanding of the current state of this unique species, provides information that may help managers prevent its disappearance from its native range, and affords insight into the interactions of an introduced and a native species in a landscape that has been heavily altered by human activity
Ethical and compliance-competence evaluation: a key element of sound corporate governance
Motivated by the ongoing post-Enron refocusing on corporate governance and the shift by the Financial Services Authority (FSA) in the UK to promoting compliance- competence within the financial services sector, this paper demonstrates how template analysis can be used as a tool for evaluating compliance-competence. Focusing on the ethical dimension of compliance-competence, we illustrate how this can be subjectively appraised. We propose that this evaluation technique could be utilised as a starting point in informing senior management of corporate governance issues and be used to monitor and demonstrate key compliance and ethical aspects of an institution to external stakeholders and regulators
The Power of Information and Communities of Color
In this age of the Information Superhighway, access to information has become a human rights issue for communities of color. Access to information is the backbone for economic growth in the world marketplace. Information literacy, the ability to find, evaluate, analyze, and use information effectively is the currency of infinite power and control of one\u27s economic, social, and political destiny. For communities of color to gain access to this phenomenal communications/technological revolution, there is a need to become information literate
Climatic and Biogeochemical Effects of a Galactic Gamma-Ray Burst
It is likely that one or more gamma-ray bursts within our galaxy have
strongly irradiated the Earth in the last Gy. This produces significant
atmospheric ionization and dissociation, resulting in ozone depletion and
DNA-damaging ultraviolet solar flux reaching the surface for up to a decade.
Here we show the first detailed computation of two other significant effects.
Visible opacity of NO2 is sufficient to reduce solar energy at the surface up
to a few percent, with the greatest effect at the poles, which may be
sufficient to initiate glaciation. Rainout of dilute nitric acid is could have
been important for a burst nearer than our conservative nearest burst. These
results support the hypothesis that the characteristics of the late Ordovician
mass extinction are consistent with GRB initiation.Comment: 12 pages, 2 figures, in press at Geophysical Research Letters. Minor
revisions, including details on falsifying the hypothesi
- …