We present a measure of the hard (2Y8 keV ) X-ray luminosity function (XLF) of AGNs up to z $ 5. At high redshifts, the wide area coverage of the Chandra Multiwavength Project is crucial to detect rare and luminous (L X > 10 44 ergs s À1 ) AGNs. The inclusion of samples from deeper published surveys, such as the Chandra Deep Fields, allows us to span the lower L X range of the XLF. Our sample is selected from both the hard (z < 3, f 2Y8 keV > 6:3 ; 10 À16 ergs cm À2 s À1 ) and soft (z > 3, f 0:5Y2:0 keV > 1:0 ; 10 À16 ergs cm À2 s À1 ) energy band detections. Within our optical magnitude limits (r 0 ; i 0 < 24), we achieve an adequate level of completeness (>50%) regarding X-ray source identification (i.e., redshift). We find that the luminosity function is similar to that found in previous X-ray surveys up to z $ 3 with an evolution dependent on both luminosity and redshift. At z > 3, there is a significant decline in the numbers of AGNs with an evolution rate similar to that found by studies of optically selected QSOs. Based on our XLF, we assess the resolved fraction of the cosmic X-ray background, the cumulative mass density of SMBHs, and the comparison of the mean accretion rate onto SMBHs and the star formation history of galaxies as a function of redshift. A coevolution scenario up to z $ 2 is plausible, although at higher redshifts the accretion rate onto SMBHs drops more rapidly. Finally, we highlight the need for better statistics of high-redshift AGNs at z k 3, which is achievable with the upcoming Chandra surveys.

Our data suggest that the TLR4+896A>G polymorphism is a risk factor for noncardia gastric carcinoma and its precursors. The findings underscore the role of the host innate immune response in outcome of H pylori infection.

Gastric cancer remains a global killer with a shifting burden from the developed to the developing world. The cancer develops along a multistage process that is defined by distinct histological and pathophysiological phases. Several genetic and epigenetic alterations mediate the transition from one stage to another and these include mutations in oncogenes, tumour suppressor genes and cell cycle and mismatch repair genes. The most significant advance in the fight against gastric cancer came with the recognition of the role of Helicobacter pylori (H pylori) as the most important acquired aetiological agent for this cancer. Recent work has focussed on elucidating the complex host/microbial interactions that underlie the neoplastic process. There is now considerable insight into the pathogenesis of this cancer and the prospect of preventing and eradicating the disease has become a reality. Perhaps more importantly, the study of H pylori-induced gastric carcinogenesis offers a paradigm for understanding more complex human cancers. In this review, we examine the molecular and cellular events that underlie H pylori-induced gastric cancer.

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Summary 0[ The present study investigated breeding success and causes of breeding failure of curlew\ a species for which the UK holds internationally important breeding numbers[ Studies were undertaken between 0882 and 0884 in two areas of Northern Ireland\ where the species| breeding range has recently contracted and breeding numbers are declining[ Avian nest predators were abundant in both areas\ whereas foxes were abundant on the Antrim study area but generally were absent from the Lough Erne study area\ which was mainly islands[ 1[ Productivity was estimated to be 9=03Ð9=15~edglings per pair in Antrim and 9=19Ð 9=36~edglings per pair on Lough Erne[ These _gures are lower than most estimates of productivity from other studies of breeding curlew[ The di}erences between the recorded productivity levels and those estimated to be required to maintain a stable population are su.cient to account for the observed decline in Northern Ireland|s breeding curlew population[ 2[ Predation was the main proximate cause of breeding failure\ with nest predation being of most importance in reducing productivity[ Only 2=5Ð08=9) of all nests hatched on each study area in each year\ with nest predation accounting for 74Ð86) of failures[ Survival of chicks from hatching to 20 days of age was 27=4) in Antrim and 08=0Ð18=1) on Lough Erne[ Predation accounted for 63) of chick mortality[ 3[ Nest failure rates were not related to the vegetation height around nests nor to clutch laying date on either study area[ They di}ered among the islands and one shoreside site on Lough Erne[ Almost all nest predation on Lough Erne was attribu! table to avian predators\ but in Antrim foxes probably accounted for most nest predation[ The likelihood of predation on chicks was not related to their hatching date\ hatching weight or body condition[ 4[ The results from this study suggest that predation rates on curlew nests in Northern Ireland may have increased in recent decades[ Levels of predator control in Northern Ireland have declined but there have also been considerable changes in land!use that could bene_t generalist predator species or increase the vulnerability of curlew nests to predation[ It is recommended that large!scale trials of legalized predator control and land!use manipulation should be undertaken to identify appropriate conservation management methods[ Key!words] breeding waders\ nesting success\ population decline\ predation[ Journal of Applied Ecology "0888# 25\ 48Ð63