1,502 research outputs found
CMB signal in WMAP 3yr data with FastICA
We present an application of the fast Independent Component Analysis
(FastICA) to the WMAP 3yr data with the goal of extracting the CMB signal. We
evaluate the confidence of our results by means of Monte Carlo simulations
including CMB, foreground contaminations and instrumental noise specific of
each WMAP frequency band. We perform a complete analysis involving all or a
subset of the WMAP channels in order to select the optimal combination for CMB
extraction, using the frequency scaling of the reconstructed component as a
figure of merit. We found that the combination KQVW provides the best CMB
frequency scaling, indicating that the low frequency foreground contamination
in Q, V and W bands is better traced by the emission in the K band. The CMB
angular power spectrum is recovered up to the degree scale, it is consistent
within errors for all WMAP channel combination considered, and in close
agreement with the WMAP 3yr results. We perform a statistical analysis of the
recovered CMB pattern, and confirm the sky asymmetry reported in several
previous works with independent techniques.Comment: 10 pages, 7 figures, submitted to MNRA
Challenging women’s vulnerability
This paper considers explanations of rape related to perceptions of women’s
vulnerability and of men’s violence and strength as problematic, because of the
limitations they impose on women’s agency. Under the framework of poststructuralist
feminist politics of rape and politics of representation, it analyses
how to bring about change, in relation to these beliefs, at the level of
discourses. The principal justification to focus on the production of discourses
rests on the argument that ideas of women’s vulnerability and men’s strength
participate in constructing discourses that legitimise and normalise rape. These
reflections are then used to look at the experience of “Sexto Sentido,” a
Nicaraguan feminist telenovela, produced to incite stimulating critical
reflection and debate on different oppressive relations of power. More
specifically, this study discursively analyses how this soap opera challenges
dominant discourses on masculinity, femininity and rape in Nicaragua. Overall,
the paper critically discusses the potentialities and challenges of fostering social
change through discourses
Border Studies
In the last two decades, a novel interdisciplinary field of inquiry has emerged under the label of Border Studies. This area of research has mainly reflected on the nature and functionalities of borders and boundaries, bringing up discussions on space, politics, economics, and culture. In particular, Border Studies have significantly contributed to the understanding of the role of borders in shaping migratory movements. In order to map this very large field of investigation, numerous state of the art reviews have been published. However, none of the reviews encountered has addressed the following issues: first, the main assumptions informing different theoretical perspectives in Border Studies; second, the application of Border Studies to analyse human mobility in the Global South. Thus, in order to participate in producing a more complete understanding of the knowledge produced in this field, the present paper pursues a pair of objectives. One objective is to critically present the main theoretical approaches employed in the field of Border Studies, reflecting on their heuristic possibilities and limitations as well as their political implications. The other objective is to explore the intertwining of Border and Migration Studies with a specific focus on Africa, Asia and Latin America, devoting particular attention to the way this body of research has analysed the condition of migrant women workers. Overall, the essay generates suggestions for future significant investigations
An optical spectroscopic survey of the 3CR sample of radio galaxies with z<0.3. III. Completing the sample
We present optical nuclear spectra for nine 3CR radio sources obtained with
the Telescopio Nazionale Galileo, that complete our spectroscopic observations
of the sample up to redshifts 0.3. We measure emission line luminosities
and ratios, and derive a spectroscopic classification for these sources.Comment: Accepted for publication in A&A. We provide as additional material
two tables presenting the main data for the whole sample, combining the
results presented here with those of Paper I and Paper I
Flexibility properties in Complex Analysis and Affine Algebraic Geometry
In the last decades affine algebraic varieties and Stein manifolds with big
(infinite-dimensional) automorphism groups have been intensively studied.
Several notions expressing that the automorphisms group is big have been
proposed. All of them imply that the manifold in question is an
Oka-Forstneri\v{c} manifold. This important notion has also recently merged
from the intensive studies around the homotopy principle in Complex Analysis.
This homotopy principle, which goes back to the 1930's, has had an enormous
impact on the development of the area of Several Complex Variables and the
number of its applications is constantly growing. In this overview article we
present 3 classes of properties: 1. density property, 2. flexibility 3.
Oka-Forstneri\v{c}. For each class we give the relevant definitions, its most
significant features and explain the known implications between all these
properties. Many difficult mathematical problems could be solved by applying
the developed theory, we indicate some of the most spectacular ones.Comment: thanks added, minor correction
Avaliação do modelo CANEGRO/DSSAT para quatro cultivares de cana-de-açúcar.
A parametrização do modelo DSSAT/CANEGRO para a realidade brasileira é de grande importância para a obtenção de uma ferramenta para o monitoramento de safras agrícolas e para a elaboração de cenários agrícolas futuros. O presente trabalho enfocou as cultivares R570, NCo376, RB72-454 e SP83-2847 nas condições de Piracicaba/SP. Os dados biométricos foram coletados no Centro de Tecnologia Canavieira, comparando-se os valores observados com as simulações para as seguintes variáveis: perfilhamento, altura de colmo, IAF, número de folhas verdes; e a fitomassa da parte aérea. O modelo apresentou resultados satisfatórios para todas as cultivares testadas, com exceção da NCo376, para a qual houve subestimativa da massa seca da parte aérea (-32%) e índice de área foliar (-13%).CBA 2009
The Jet of 3C 17 and the Use of Jet Curvature as a Diagnostic of the X-ray Emission Process
We report on the X-ray emission from the radio jet of 3C 17 from Chandra
observations and compare the X-ray emission with radio maps from the VLA
archive and with the optical-IR archival images from the Hubble Space
Telescope. X-ray detections of two knots in the 3C 17 jet are found and both of
these features have optical counterparts. We derive the spectral energy
distribution for the knots in the jet and give source parameters required for
the various X-ray emission models, finding that both IC/CMB and synchrotron are
viable to explain the high energy emission. A curious optical feature (with no
radio or X-ray counterparts) possibly associated with the 3C 17 jet is
described. We also discuss the use of curved jets for the problem of
identifying inverse Compton X-ray emission via scattering on CMB photons.Comment: 6 pages, 6 figure (3 in color), 4 tables, ApJ accepte
Hydatid disease of the liver: thirty years of surgical experience.
Hydatid disease of the liver is a relatively frequent disease. Although the natural history is almost completely known, several complications may occur. The aim of this study was to show that radical surgical resection of the hepatic hydatid cyst is a safe and very effective technique, based on our results after 30-year experience. A review of most significant studies was carried out. We retrospectively evaluated our surgical cases. From January 1973 to December 2003 we treated 216 patients, 98 males and 118 females. Survival was compared with the Kaplan-Meier test, using log-rank analysis to compare data. Differences with a p value less than 0.05 were considered significant. A total of 279 cysts were excised. We performed pericystectomy in 122 cases, 73 of which closed. We also performed 19 atypical resections, 10 segmentectomies, 20 lobectomies and 2 percutaneous treatments. In more than 90% of cases, preoperative data collection was completed by preoperative ultrasound. The cumulative morbidity was 13%. The recurrence rate amounted to 4.3% at 5 years and 7% at 10 years: of these, 6 occurred after non-radical surgery and 2 after total pericystectomy or liver resection (p < 0.001). Technical advances and accumulated experience permit safe treatment of hepatic hydatid cysts by radical resection, with an almost zero recurrence rate, making it the treatment of choice over partial resection. The utility of percutaneous treatment remains confined to limited indications, such as laparoscopy
The merging/AGN connection II. Ionization of the circumnuclear regions
We report the first results of a study of a sample of 20 galaxy
mergers/interacting systems, using the VIMOS and PMAS integral field
spectrographs. For each object, we extracted the integrated spectrum of the
central regions and analyzed the ionization state using classical diagnostic
diagrams (Veilleux & Osterbrock 1987). There is evidence of AGN ionization in 4
of the objects, i.e. 20% of the sample, a considerably higher fraction than
found in previous studies ~4%Comment: 4 pages, 2 figures, accepted for publishing in A&A Letter
Convection in colloidal suspensions with particle-concentration-dependent viscosity
The onset of thermal convection in a horizontal layer of a colloidal
suspension is investigated in terms of a continuum model for binary-fluid
mixtures where the viscosity depends on the local concentration of colloidal
particles. With an increasing difference between the viscosity at the warmer
and the colder boundary the threshold of convection is reduced in the range of
positive values of the separation ratio psi with the onset of stationary
convection as well as in the range of negative values of psi with an
oscillatory Hopf bifurcation. Additionally the convection rolls are shifted
downwards with respect to the center of the horizontal layer for stationary
convection (psi>0) and upwards for the Hopf bifurcation (psi<0).Comment: 8 pages, 6 figures, submitted to European Physical Journal
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