28 research outputs found

    XMM-Newton Surveys of the Canada-France Redshift Survey Fields - III: The Environments of X-ray Selected AGN at 0.4<z<0.6

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    The environmental properties of a sample of 31 hard X-ray selected AGN are investigated, from scales of 500 kpc down to 30 kpc, and are compared to a control sample of inactive galaxies. The AGN all lie in the redshift range 0.4<z<0.6. The accretion luminosity-density of the Universe peaks close to this redshift range, and the AGN in the sample have X-ray luminosities close to the knee in the hard X-ray luminosity function, making them representative of the population which dominated this important phase of energy conversion. Using both the spatial clustering amplitude and near neighbour counts it is found that the AGN have environments that are indistinguishable from normal, inactive galaxies over the same redshift range and with similar optical properties. Typically, the environments are of sub-cluster richness, in contrast to similar studies of high-z quasars, which are often found in clusters with comparable richness to the Abell R>=0 clusters. It is suggested that minor mergers with low mass companions is a likely candidate for the mechanism by which these modest luminosity AGN are fuelled.Comment: 12 pages, 6 figures, accepted by MNRA

    XMM—Newton surveys of the Canada—France Redshift Survey Fields — III. The environments of X-ray selected active galactic nuclei at 0.4 < z < 0.6

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    The environmental properties of a sample of 31 hard X-ray selected active galactic nuclei (AGN) are investigated, from scales of 500 kpc down to 30 kpc, and are compared to a control sample of inactive galaxies. All the AGN lie in the redshift range 0.4 < z < 0.6. The accretion luminosity density of the Universe peaks close to this redshift range, and the AGN in the sample have X-ray luminosities close to the knee in the hard X-ray luminosity function, making them representative of the population that dominated this important phase of energy conversion. Using both the spatial clustering amplitude and near-neighbour counts, it is found that the AGN have environments that are indistinguishable from normal, inactive galaxies over the same redshift range and with similar optical properties. Typically, the environments are of subcluster richness, in contrast to similar studies of high-z quasars, which are often found in clusters with comparable richness to the Abell R≥ 0 clusters. It is suggested that minor mergers with low-mass companions are a likely candidate for the mechanism by which these modest luminosity AGN are fuelle

    Determining the optimum scan map strategy for Herschel-SPIRE using the SPIRE photometer simulator

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    The forthcoming Herschel space mission will provide an unprecedented view of the far-infrared/submillimetre Universe, with the SPIRE instrument covering the 200–670 μm wavelength range. To obtain the best quality of astronomical data from such an expensive mission the observing modes must be optimized as far as possible. This paper presents the possible scanning strategies that can be utilized by the SPIRE photometer, within the limitations imposed by the Herschel spacecraft. Each strategy is investigated for effectiveness by performing simulated observations, using the SPIRE photometer simulator. By quantifying the data quality using a simple metric, we have been able to select the optimum scanning strategy for SPIRE when it begins taking science data within the next couple of years. Additionally, this work has led to the development of a specific SPIRE mapmaking algorithm, based on the CMB code MADmap, to be provided as part of the SPIRE data pipeline processing suite. This will allow every SPIRE user to take full advantage of the optimized scan map strategy, which requires the use of maximum likelihood mapmakers such as MADmap

    XMM-Newton surveys of the Canada-France Redshift Survey fields - II. The X-ray catalogues, the properties of the host galaxies and the redshift distribution

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    We present the X-ray source catalogues for the XMM surveys of the 3-h and 14-h Canada-France Redshift Survey fields (0.5-10 keV flux range ∼2 × 10−15-10−13 erg cm−2 s−1). We use a subset of the XMM sources, which have Chandra positions, to determine the best method of obtaining optical identifications of sources with only XMM positions. We find optical identifications for 79 per cent of the XMM sources for which there are deep optical images. The sources without optical identifications are likely to be optically fainter and have higher redshifts than the sources with identifications. We have estimated ‘photometric redshifts' for the identified sources, calibrating our method using ∼200 galaxies in the fields with spectroscopic redshifts. We find that the redshift distribution has a strong peak at z∼ 0.7. The host galaxies of active galactic nuclei (AGN) identified in this work cover a wide range of optical properties, with every galaxy type being represented and no obvious preference for one type over another. Redder types tend to be more luminous than blue types, particularly at lower redshifts. The host galaxies also span a wide range of optical luminosity, in contrast to the narrow range found for the starburst galaxies detected in μJy radio surveys. We find a strong correlation between optical and X-ray luminosity similar to the Magorrian relation, although selection effects cannot be ruled ou

    The Strong Protective Effect of Circumcision against Cancer of the Penis

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    Male circumcision protects against cancer of the penis, the invasive form of which is a devastating disease confined almost exclusively to uncircumcised men. Major etiological factors are phimosis, balanitis, and high-risk types of human papillomavirus (HPV), which are more prevalent in the glans penis and coronal sulcus covered by the foreskin, as well as on the penile shaft, of uncircumcised men. Circumcised men clear HPV infections more quickly. Phimosis (a constricted foreskin opening impeding the passage of urine) is confined to uncircumcised men, in whom balanitis (affecting 10%) is more common than in circumcised men. Each is strongly associated with risk of penile cancer. These findings have led to calls for promotion of male circumcision, especially in infancy, to help reduce the global burden of penile cancer. Even more relevant globally is protection from cervical cancer, which is 10-times more common, being much higher in women with uncircumcised male partners. Male circumcision also provides indirect protection against various other infections in women, along with direct protection for men from a number of genital tract infections, including HIV. Given that adverse consequences of medical male circumcision, especially when performed in infancy, are rare, this simple prophylactic procedure should be promoted

    XMM-Newton Surveys of the Canada-France Redshift Survey Fields - II: The X-ray Catalogues, the Properties of the Host Galaxies, and the Redshift Distribution

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    We present the X-ray source catalogues for the XMM surveys of the 3-h and 14-h Canada-France Redshift Survey fields (0.5-10 keV flux range ~2E-15 - 1E-13 erg cm^-2 s^-1). We use a subset of the XMM sources, which have Chandra positions, to determine the best method of obtaining optical identifications of sources with only XMM positions. We find optical identifications for 79% of the XMM sources for which there are deep optical images. The sources without optical identifications are likely to be optically fainter and have higher redshifts than the sources with identifications. We have estimated `photometric redshifts' for the identified sources, calibrating our method using ~200 galaxies in the fields with spectroscopic redshifts. We find that the redshift distribution has a strong peak at z~0.7. The host galaxies of AGN identified in this work cover a wide range of optical properties with every galaxy type being represented, and no obvious preference for one type over another. Redder types tend to be more luminous than blue types, particularly at lower redshifts. The host galaxies also span a wide range of optical luminosity, in contrast to the narrow range found for the starburst galaxies detected in micro Jy radio surveys. We find a strong correlation between optical and X-ray luminosity similar to the Magorrian relation, although selection effects cannot be ruled out.Comment: 14 pages, 11 figure, accepted to MNRA

    Game Plan: What AI can do for Football, and What Football can do for AI

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    The rapid progress in artificial intelligence (AI) and machine learning has opened unprecedented analytics possibilities in various team and individual sports, including baseball, basketball, and tennis. More recently, AI techniques have been applied to football, due to a huge increase in data collection by professional teams, increased computational power, and advances in machine learning, with the goal of better addressing new scientific challenges involved in the analysis of both individual players’ and coordinated teams’ behaviors. The research challenges associated with predictive and prescriptive football analytics require new developments and progress at the intersection of statistical learning, game theory, and computer vision. In this paper, we provide an overarching perspective highlighting how the combination of these fields, in particular, forms a unique microcosm for AI research, while offering mutual benefits for professional teams, spectators, and broadcasters in the years to come. We illustrate that this duality makes football analytics a game changer of tremendous value, in terms of not only changing the game of football itself, but also in terms of what this domain can mean for the field of AI. We review the state-of-theart and exemplify the types of analysis enabled by combining the aforementioned fields, including illustrative examples of counterfactual analysis using predictive models, and the combination of game-theoretic analysis of penalty kicks with statistical learning of player attributes. We conclude by highlighting envisioned downstream impacts, including possibilities for extensions to other sports (real and virtual)

    Review: A critical evaluation of arguments opposing male circumcision for HIV prevention in developed countries

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    A potential impediment to evidence-based policy development on medical male circumcision (MC) for HIV prevention in all countries worldwide is the uncritical acceptance by some of arguments used by opponents of this procedure. Here we evaluate recent opinion-pieces of 13 individuals opposed to MC. We find that these statements misrepresent good studies, selectively cite references, some containing fallacious information, and draw erroneous conclusions. In marked contrast, the scientific evidence shows MC to be a simple, low-risk procedure with very little or no adverse long-term effect on sexual function, sensitivity, sensation during arousal or overall satisfaction. Unscientific arguments have been recently used to drive ballot measures aimed at banning MC of minors in the USA, eliminate insurance coverage for medical MC for low-income families, and threaten large fines and incarceration for health care providers. Medical MC is a preventative health measure akin to immunisation, given its protective effect against HIV infection, genital cancers and various other conditions. Protection afforded by neonatal MC against a diversity of common medical conditions starts in infancy with urinary tract infections and extends throughout life. Besides protection in adulthood against acquiring HIV, MC also reduces morbidity and mortality from multiple other sexually transmitted infections (STIs) and genital cancers in men and their female sexual partners. It is estimated that over their lifetime one-third of uncircumcised males will suffer at least one foreskin-related medical condition. The scientific evidence indicates that medical MC is safe and effective. Its favourable risk/benefit ratio and cost/benefit support the advantages of medical MC

    Catalog of Radio Galaxies with z>0.3. I:Construction of the Sample

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    The procedure of the construction of a sample of distant (z>0.3z>0.3) radio galaxies using NED, SDSS, and CATS databases for further application in statistical tests is described. The sample is assumed to be cleaned from objects with quasar properties. Primary statistical analysis of the list is performed and the regression dependence of the spectral index on redshift is found.Comment: 9 pages, 6 figures, 2 table
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