Um olhar sobre o novo: Orkut é ferramenta de pesquisa

Verifica a pertinência do uso do site de relacionamentos “Orkut” como ferramenta adicional de pesquisa de mercado. Primeiramente, o estudo aborda de que forma a necessidade de informação é fundamental como parte do processo de busca para uma comunicação eficiente. Procura então entender a pesquisa como fonte principal, organizada e legitimada, na obtenção dessas informações. A seguir, o estudo traz um panorama de como a Internet está mudando, discute novos conceitos como “Web 2.0” e “antropologia virtual” e busca entender novas ferramentas como blogs e comunidades virtuais. Através de entrevistas com profissionais do mercado que lidam com pesquisa, leituras afins e observação, o trabalho busca definir, traçar um histórico, rever a importância e ilustrar usos do site de relacionamentos “Orkut”, discutindo a seguir seus métodos, usos, vantagens e por outro lado riscos e limites como ferramenta de pesquisa, traçando paralelos com métodos tradicionais

First Results from the XMM-Newton Slew Survey

We have attempted to analyse all the available data taken by XMM-Newton as it slews between targets. This slew survey, the resultant source catalogue and the analysis procedures used are described in an accompanying paper. In this letter we present the initial science results from the survey. To date, detailed source-searching has been performed in three X-ray bands (soft, hard and total) in the EPIC-pn 0.2-12 keV band over ~6300 sq.degrees (~15% of the sky), and of order 4000 X-ray sources have been detected (~55% of which have IDs). A great variety of sources are seen, including AGN, galaxies, clusters and groups, active stars, SNRs, low- and high-mass XRBs and white dwarfs. In particular, as this survey constitutes the deepest ever hard-band 2-12 keV all-sky survey, a large number of hard sources are detected. Furthermore, the great sensitivity and low-background of the EPIC-pn camera are especially suited to emission from extended sources, and interesting spatial structure is observed in many supernova remnants and clusters of galaxies. The instrument is very adept at mapping large areas of the X-ray sky. Also, as the slew survey is well matched to the ROSAT all-sky survey, long-term variability studies are possible, and a number of extremely variable X-ray sources, some possibly due to the tidal disruption of stars by central supermassive black holes, have been discovered.Comment: 4 Pages, 3 Figs, to appear in PASJ (2006) 58, No 6. Colour version available at http://www.star.le.ac.uk/~amr30/publications.htm

The Herschel PACS photometer calibration - A time dependent flux calibration for the PACS chopped point-source photometry AOT mode

We present a flux calibration scheme for the PACS chopped point-source photometry observing mode based on the photometry of five stellar standard sources. This mode was used for science observations only early in the mission. Later, it was only used for pointing and flux calibration measurements. Its calibration turns this type of observation into fully validated data products in the Herschel Science Archive. Systematic differences in calibration with regard to the principal photometer observation mode, the scan map, are derived and amount to 5-6%. An empirical method to calibrate out an apparent response drift during the first 300 Operational Days is presented. The relative photometric calibration accuracy (repeatability) is as good as 1% in the blue and green band and up to 5% in the red band. Like for the scan map mode, inconsistencies among the stellar calibration models become visible and amount to 2% for the five standard stars used. The absolute calibration accuracy is therefore mainly limited by the model uncertainty, which is 5% for all three bands.Comment: 20 pages, 7 pages of appendix, 11 figures, accepted to appear in Experimental Astronomy, Special Issue for Herschel Calibrations based on the "Herschel Calibration Workshop: Only the Best Data Products for the Legacy Archive", held at ESAC, 25 - 27 March 2013, http://herschel.esac.esa.int/CalibrationWorkshop5.shtm

The reversal of the SF-density relation in a massive, X-ray selected galaxy cluster at z=1.58: results from Herschel

Dusty, star-forming galaxies have a critical role in the formation and evolution of massive galaxies in the Universe. Using deep far-infrared imaging in the range 100-500um obtained with the Herschel telescope, we investigate the dust-obscured star formation in the galaxy cluster XDCP J0044.0-2033 at z=1.58, the most massive cluster at z >1.5, with a measured mass M200= 4.7x10$^{14}$ Msun. We perform an analysis of the spectral energy distributions (SEDs) of 12 cluster members (5 spectroscopically confirmed) detected with >3$\sigma$ significance in the PACS maps, all ULIRGs. The individual star formation rates (SFRs) lie in the range 155-824 Ms/yr, with dust temperatures of 24$\pm$35 K. We measure a strikingly high amount of star formation (SF) in the cluster core, SFR ( 1875$\pm$158 Ms/yr, 4x higher than the amount of star formation in the cluster outskirts. This scenario is unprecedented in a galaxy cluster, showing for the first time a reversal of the SF-density relation at z~1.6 in a massive cluster.Comment: Letter accepted for publication in MNRAS, ESA Press Release on 18 December 201

Star formation in the cluster CLG0218.3-0510 at z=1.62 and its large-scale environment: the infrared perspective

The galaxy cluster CLG0218.3-0510 at z=1.62 is one of the most distant galaxy clusters known, with a rich muti-wavelength data set that confirms a mature galaxy population already in place. Using very deep, wide area (20x20 Mpc) imaging by Spitzer/MIPS at 24um, in conjunction with Herschel 5-band imaging from 100-500um, we investigate the dust-obscured, star-formation properties in the cluster and its associated large scale environment. Our galaxy sample of 693 galaxies at z=1.62 detected at 24um (10 spectroscopic and 683 photo-z) includes both cluster galaxies (i.e. within r <1 Mpc projected clustercentric radius) and field galaxies, defined as the region beyond a radius of 3 Mpc. The star-formation rates (SFRs) derived from the measured infrared luminosity range from 18 to 2500 Ms/yr, with a median of 55 Ms/yr, over the entire radial range (10 Mpc). The cluster brightest FIR galaxy, taken as the centre of the galaxy system, is vigorously forming stars at a rate of 256$\pm$70 Ms/yr, and the total cluster SFR enclosed in a circle of 1 Mpc is 1161$\pm$96 Ms/yr. We estimate a dust extinction of about 3 magnitudes by comparing the SFRs derived from [OII] luminosity with the ones computed from the 24um fluxes. We find that the in-falling region (1-3 Mpc) is special: there is a significant decrement (3.5x) of passive relative to star-forming galaxies in this region, and the total SFR of the galaxies located in this region is lower (130 Ms/yr/Mpc2) than anywhere in the cluster or field, regardless of their stellar mass. In a complementary approach we compute the local galaxy density, Sigma5, and find no trend between SFR and Sigma5. However, we measure an excess of star-forming galaxies in the cluster relative to the field by a factor 1.7, that lends support to a reversal of the SF-density relation in CLG0218.Comment: accepted for publication in MNRAS. v2: minor correction

The Pointing System of the Herschel Space Observatory. Description, Calibration, Performance and Improvements

We present the activities carried out to calibrate and characterise the performance of the elements of attitude control and measurement on board the Herschel spacecraft. The main calibration parameters and the evolution of the indicators of the pointing performance are described, from the initial values derived from the observations carried out in the performance verification phase to those attained in the last year and half of mission, an absolute pointing error around or even below 1 arcsec, a spatial relative pointing error of some 1 arcsec and a pointing stability below 0.2 arsec. The actions carried out at the ground segment to improve the spacecraft pointing measurements are outlined. On-going and future developments towards a final refinement of the Herschel astrometry are also summarised. A brief description of the different components of the attitude control and measurement system (both in the space and in the ground segments) is also given for reference. We stress the importance of the cooperation between the different actors (scientists, flight dynamics and systems engineers, attitude control and measurement hardware designers, star-tracker manufacturers, etc.) to attain the final level of performance.Comment: 28 pages, 8 figures, accepted for publication in Experimental Astronom

The Benefits of Using XML Technologies in Astronomical Data Retrieval and Interpretation

This paper describes a solution found during recent research that could provide improvements in the efficiency, reliability and cost of retrieving stored astronomical data. This solution uses XML Technologies in showing that when querying a variety of astronomical data sources a standardised data structure can be output into an XML query results Document. This paper shows the astronomical XMLSchema that has been partially developed in conjunction with simple custom supporting system software. It also discusses briefly possible future implications

Shmt2: a stat3 signaling new player in prostate cancer energy metabolism

Prostate cancer (PCa) is a multifactorial disease characterized by the aberrant activity of different regulatory pathways. STAT3 protein mediates some of these pathways and its activation is implicated in the modulation of several metabolic enzymes. A bioinformatic analysis indicated a STAT3 binding site in the upstream region of SHMT2 gene. We demonstrated that in LNCaP, PCa cells' SHMT2 expression is upregulated by the JAK2/STAT3 canonical pathway upon IL-6 stimulation. Activation of SHTM2 leads to a decrease in serine levels, pushing PKM2 towards the nuclear compartment where it can activate STAT3 in a non-canonical fashion that in turn promotes a transient shift toward anaerobic metabolism. These results were also confirmed on FFPE prostate tissue sections at different Gleason scores. STAT3/SHMT2/PKM2 loop in LNCaP cells can modulate a metabolic shift in response to inflammation at early stages of cancer progression, whereas a non-canonical STAT3 activation involving the STAT3/HIF-1α/PKM2 loop is responsible for the maintenance of Warburg effect distinctive of more aggressive PCa cells. Chronic inflammation might thus prime the transition of PCa cells towards more advanced stages, and SHMT2 could represent a missing factor to further understand the molecular mechanisms responsible for the transition of prostate cancer towards a more aggressive phenotyp

The cosmological analysis of X-ray cluster surveys: II- Application of the CR-HR method to the XMM archive

We have processed 2774 high-galactic observations from the XMM archive (as of May 2010) and extracted a serendipitous catalogue of some 850 clusters of galaxies based on purely X-ray criteria, following the methodology developed for the XMM-LSS survey. Restricting the sample to the highest signal-to-noise objects (347 clusters), we perform a cosmological analysis using the X-ray information only. The analysis consists in the modelling of the observed colour-magnitude (CR-HR) diagram constructed from cluster instrumental count-rates measured in the [0.5-2], [1-2] and [0.5-1] keV bands. A MCMC procedure simultaneously fits the cosmological parameters, the evolution of the cluster scaling laws and the selection effects. Our results are consistent with the sigma_8 and Omega_m values obtained by WMAP-5 and point toward a negative evolution of the cluster scaling relations with respect to the self-similar expectation. We are further able to constrain the cluster fractional radius xc0=r_c/r500c, to xc0=0.24 +/- 0.04. This study stresses again the critical role of selection effects in deriving cluster scaling relations, even in the local universe. Finally, we show that CR-HR method applied to the eRosita all-sky survey - provided that cluster photometric redshifts are available - will enable the determination of the equation of state of the dark energy at the level of the DETF stage IV predictions; simultaneously, the evolution of the cluster scaling-relations will be unambiguously determined. The XMM CLuster Archive Super Survey (XCLASS) serendipitous cluster catalogue is available online at: http://xmm-lss.in2p3.fr:8080/l4sdb/.Comment: 26 pages, 24 figures, 9 tables. Accepted for publication in MNRAS (minor changes with respect to submitted version). The corresponding galaxy cluster catalogue is available at http://xmm-lss.in2p3.fr:8080/l4sdb