324 research outputs found
Ruinous Natures: The Approach of Social Timespace
This Dissertation advances across three areas: first, a theory of social timespace that borrows from critical social theories, post-ontological systems theory, and literary critique; second, it proposes a revisioning of sociological ‘methods’ by an historical reproachment: how sociology is a method among others for the study of society and culture, what are called variously the social sciences, and how sociology also has a method of its own developed in the work of the first sociological institutions in the United States, Germany, and France, that is parallel to linguistic structuralism in the same historical period and has mostly been advanced outside the discipline in narrative and discourse analysis; third, the substantive matter of this dissertation concerns a shift in the sociology of the environment to a political ecology, and critique of the latter. The binding theoretic development, mode of analysis, and the object of a political ecology formed in environmental sociology, are configured under the singular term of socioanalysis. The technique of socioanalysis, its eco-environmental object, and theory implied by the practice of socioanalysis are the guiding proposition of this research
Remodelatge de la cromatina durant la inducció per progesterona del promotor de l'MMTV
Per a comprendre els mecanismes que governen l'expressió dels gens inclosos en els genomes
eucariòtics és necessari prendre en consideració la manera en què les regions reguladores
d'aquests gens estan organitzades en la cromatina. Les diferències en l'organització de la cromatina
i en les modificacions químiques dels components de la cromatina expliquen els diferents
patrons de l'expressió gènica en diversos tipus de cèll. ules i la seva resposta específica a senyals
externs. Basant-nos en els nostres estudis sobre la inducció hormonal del promotor del mouse
mammary tumour virus (MMTV), podem concloure que la seqüència nucleotídica primària
determina no solament la manera en què la doble hèlix de DNA envolta l'octàmer d'histona,
i així l'accessibilitat de punts d'unió per als factors de transcripció, sinó també la manera en
què aquests factors estableixen sinergismes i la naturalesa del remodelatge de la cromatina dependent
d'ATP. A més, la senyalització via crosstalk amb cascades de cinases citoplasmàtiques
canvia l'estructura de la cromatina en els gens diana i és fonamental per a la correcta regulació
a través de receptors d'hormones esteroidees.Understanding the mechanisms governing the expression of the genes encompassed in the
eukaryotic genomes requires a careful consideration of the way regulatory regions of these
genes are packaged in chromatin. Differences in the chromatin organization and in the chemical
modifications of chromatin components account for the different patterns of gene expression
in various cell types and for their specific response to external signals. Based on our studies on the hormonal induction of mouse mammary tumour virus (MMTV) promoter we conclude
that the primary nucleotide sequence determines not only the way theDNAdouble helix wraps
around the histone octamer, and so the accessibility of binding sites for transcription factors, but
also the way these factors synergize and the nature of the ATP-dependent chromatin remodelling.
Moreover, signalling via crosstalk with cytoplasmic kinase cascades changes the chromatin
structure of target genes and is essential for proper regulation by steroid hormone receptors
Chandra Detection of X-ray Absorption Associated with a Damped Lyman Alpha System
We have observed three quasars, PKS 1127-145, Q 1331+171 and Q0054+144, with
the ACIS-S aboard the Chandra X-ray Observatory, in order to measure soft X-ray
absorption associated with intervening 21-cm and damped Ly absorbers.
For PKS 1127-145, we detect absorption which, if associated with an intervening
z_{abs}=0.312 absorber, implies a metallicity of 23% solar. If the absorption
is not at z_{abs}=0.312, then the metallicity is still constrained to be less
than 23% solar. The advantage of the X-ray measurement is that the derived
metallicity is insensitive to ionization, inclusion of an atom in a molecule,
or depletion onto grains. The X-ray absorption is mostly due to oxygen, and is
consistent with the oxygen abundance of 30% solar derived from optical nebular
emission lines in a foreground galaxy at the redshift of the absorber.
For Q1331+171 and Q 0054+144, only upper limits were obtained, although the
exposure times were intentionally short, since for these two objects we were
interested primarily in measuring flux levels to plan for future observations.
The imaging results are presented in a companion paper.Comment: 23 pages, 6 figures, accepted for publication in the Astrophysical
Journa
X-ray emission from GPS/CSS sources
The high spatial resolution of the Chandra X-ray Observatory allows us to
study the environment of GPS/CSS sources to within an arcsec of the strong
compact core. We present the discovery of X-ray jets in two GPS quasars,
PKS1127-145 and B2 0738+393, indicating that X-ray emission associated with the
relativistic plasma is present at large distances from the GPS nucleus. We also
discuss first results from Chandra observations of our GPS/CSS sample. We find
that 6 out of 10 sources show intrinsic absorption at a level which may be
sufficient to confine the GPS source.Comment: contribution to the Third Workshop on CSS/GPS Radio Sources,
Kerastari, Greece, May 2002. Published in PASA, 2003 vol 20, p.11
Chandra Discovery of a 300 kpc X-ray Jet in the GPS Quasar PKS1127-145
We have discovered an X-ray jet with Chandra imaging of the z=1.187
radio-loud quasar PKS1127-145. In this paper we present the Chandra X-ray data,
follow-up VLA observations, and optical imaging using the HST WFPC2. The X-ray
jet contains 273+/-5 net counts in 27ksec and extends ~30 arcsec, from the
quasar core, corresponding to a minimum projected linear size of ~330/h_50 kpc.
The evaluation of the X-ray emission processes is complicated by the observed
offsets between X-ray and radio brightness peaks. We discuss the problems posed
by these observations to jet models. In addition, PKS1127-145 is a Giga-Hertz
Peaked Spectrum radio source, a member of the class of radio sources suspected
to be young or ``frustrated'' versions of FRI radio galaxies. However the
discovery of an X-ray and radio jet extending well outside the host galaxy of
PKS1127-145 suggests that activity in this and other GPS sources may be
long-lived and complex.Comment: 22 pages, 11 ps figures, 1 figure in a JPG file, 3 tables. AASTEX.
Accepted by The Astrophysical Journa
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Feasibility Study for Operable Unit 7-13/14
The Subsurface Disposal Area is a radioactive waste landfill located within the Radioactive Waste Management Complex at the Idaho National Laboratory Site in southeastern Idaho. This Feasibility Study for Operable Unit 7-13/14 analyzes options for mitigating risks to human health and the environment associated with the landfill. Analysis is conducted in accordance with the Comprehensive Environmental Response, Compensation, and Liability Act, using nine evaluation criteria to develop detailed and comparative analysis of five assembled alternatives. Assembled alternatives are composed of discrete modules. Ultimately, decision-makers will select, recombine, and sum various modules into an optimized preferred alternative and final remedial decision
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