A one-sided Prime Ideal Principle for noncommutative rings

Completely prime right ideals are introduced as a one-sided generalization of the concept of a prime ideal in a commutative ring. Some of their basic properties are investigated, pointing out both similarities and differences between these right ideals and their commutative counterparts. We prove the Completely Prime Ideal Principle, a theorem stating that right ideals that are maximal in a specific sense must be completely prime. We offer a number of applications of the Completely Prime Ideal Principle arising from many diverse concepts in rings and modules. These applications show how completely prime right ideals control the one-sided structure of a ring, and they recover earlier theorems stating that certain noncommutative rings are domains (namely, proper right PCI rings and rings with the right restricted minimum condition that are not right artinian). In order to provide a deeper understanding of the set of completely prime right ideals in a general ring, we study the special subset of comonoform right ideals.Comment: 38 page

Accretion Disk Instabilities, CDM models and their role in Quasar Evolution

We have developed a consistent analytical model to describe the observed evolution of the quasar luminosity function. Our model combines black hole mass distributions based on the Press - Schechter theory of the structure formation in the Universe with quasar luminosity functions resulting from a physics-based emission model that takes into account the time-dependent phenomena occurring in the accretion disks. Quasar evolution and CDM models are mutually constraining, therefore our model gives an estimation of the exponent, n, of the power spectrum, P(k), which is found to be -1.8 < n < -1.6. We were able to reject a generally assumed hypothesis of a constant ratio between Dark Matter Halo and the Black Hole mass, since the observed data could not be fitted under this assumption. We found that the relation between the Dark Matter Halos and Black Hole masses is better described by M_{BH}=M_{DMH}^{0.668}. This model provides a reasonable fit to the observed quasar luminosity function at redshifts higher than ~2.0. We suggest that the disagreement at lower redshift is due to mergers. Based on the agreement at high redshift, we estimated the merger rate at lower redshift, and argue that this rate should depend on the redshift, like (1+z)^3.Comment: 15 pages, 18 figures, Accepted for Publication in Ap

Are routinely collected NHS administrative records suitable for endpoint identification in clinical trials? Evidence from the West of Scotland coronary prevention study

Background: Routinely collected electronic patient records are already widely used in epidemiological research. In this work we investigated the potential for using them to identify endpoints in clinical trials.&lt;p&gt;&lt;/p&gt; Methods: The events recorded in the West of Scotland Coronary Prevention Study (WOSCOPS), a large clinical trial of pravastatin in middle-aged hypercholesterolaemic men in the 1990s, were compared with those in the record-linked deaths and hospitalisations records routinely collected in Scotland.&lt;p&gt;&lt;/p&gt; Results: We matched 99% of fatal study events by date. We showed excellent matching (97%) of the causes of fatal endpoint events and good matching (.80% for first events) of the causes of nonfatal endpoint events with a slightly lower rate of mismatching of record linkage than study events (19% of first study myocardial infarctions (MI) and 4% of first record linkage MIs not matched as MI). We also investigated the matching of non-endpoint events and showed a good level of matching, with .78% of first stroke/TIA events being matched as stroke/TIA. The primary reasons for mismatches were record linkage data recording readmissions for procedures or previous events, differences between the diagnoses in the routinely collected data and the conclusions of the clinical trial expert adjudication committee, events occurring outside Scotland and therefore being missed by record linkage data, miscoding of cardiac events in hospitalisations data as ‘unspecified chest pain’, some general miscoding in the record linkage data and some record linkage errors.&lt;p&gt;&lt;/p&gt; Conclusions: We conclude that routinely collected data could be used for recording cardiovascular endpoints in clinical trials and would give very similar results to rigorously collected clinical trial data, in countries with unified health systems such as Scotland. The endpoint types would need to be carefully thought through and an expert endpoint adjudication committee should be involved.&lt;p&gt;&lt;/p&gt

A deep ROSAT survey - IV. The evolution of X-ray-selected QSOs

We report on a new estimate of the QSO X-ray luminosity function and its evolution with redshift based on a sample of 107 QSOs detected at faint X-ray fluxes, $S{\rm(0.5-2\,keV)}>4\times10^{-15}\,$\ergcms , with the {\it ROSAT} X-ray satellite. For $q_0=0.5$, the X-ray evolution of QSOs in this sample is consistent with strong luminosity evolution, $L_{\rm X} ^*(z) \propto (1+z)^{3.25\pm0.1}$, at low redshifts ($z<1.60$) and a constant comoving space density at higher redshifts. The derived rate of evolution at low redshifts is thus significantly higher than that obtained previously for the {\it Einstein} Extended Medium Sensitivity Survey (EMSS). Indeed, most luminosity evolution models provide a very poor fit (rejected at the 99 per cent confidence level) when applied to the combined EMSS and {\it ROSAT} samples, although a polynomial evolution model, $L_{\rm X} ^*(z) \propto 10^{(1.14\,z -0.23\,z^2)}$, provides an adequate fit for $q_0=0$. For $q_0=0.5$, a simple power-law luminosity evolution model with a redshift cut-off ($L_{\rm X} ^*(z) \propto (1+z)^{2.51\pm0.1}$,Comment: Accepted for publication in MNRAS. 10 pages including 4 figures; uuencoded compressed postscript; RGO-20

Quasar clustering: evidence for an increase with redshift and implications for the nature of AGNs

The evolution of quasar clustering is investigated with a new sample of 388 quasars with 0.3<z<=2.2, B<=20.5 and Mb<-23, selected over an area of 24.6 sq. deg. in the South Galactic Pole. Assuming a two-point correlation function of the form xi(r) = (r/r_o)^-1.8, we detect clustering with r_0=6.2 +/- 1.6 h^-1 comoving Mpc at an average redshift of z=1.3. We find a 2 sigma significant increase of the quasar clustering between z=0.95 and z=1.8, independent of the quasar absolute magnitude and inconsistent with recent evidence on the evolution of galaxy clustering. If other quasar samples are added (resulting in a total data-set of 737 quasars) the increase of the quasar clustering is still favoured although it becomes less significant. We find epsilon=-2.5. Evolutionary parameters epsilon>0.0 are excluded at a 0.3% probability level, to be compared with epsilon=0.8 found for galaxies. The observed clustering properties appear qualitatively consistent with a scenario of Omega=1 CDM in which a) the difference between the quasar and the galaxy clustering can be explained as a difference in the effective bias and redshift distributions, and b) the quasars, with a lifetime of t~10^8 yr, sparsely sample halos of mass greater than M_min~10^12-10^13 h^-1 M_sun. We discuss also the possibility that the observed change in the quasar clustering is due to an increase in the fraction of early-type galaxies as quasar hosts at high z.Comment: 8 pages including 2 eps figures, LaTeX (AAS v4.0), ApJ in pres

Full Thermoelectric Characterization of Stoichiometric Electrodeposited Thin Film Tin Selenide (SnSe)

Tin selenide (SnSe) has attracted much attention in the thermoelectric community since the discovery of the record figure of merit (ZT) of 2.6 in single crystal tin selenide in 2014. There have been many reports since of the thermoelectric characterization of SnSe synthesized or manufactured by several methods, but so far none of these have concerned the electrodeposition of SnSe. In this work, stoichiometric SnSe was successfully electrodeposited at −0.50 V vs SCE as shown by EDX, XPS, UPS, and XRD. The full ZT of the electrodeposits were then measured. This was done by both a delamination technique to measure the Seebeck coefficient and electrical conductivity which showed a peak power factor of 4.2 and 5.8 μW m–1 K–2 for the as deposited and heat-treated films, respectively. A novel modified transient 3ω method was used to measure the thermal conductivity of the deposited films on the deposition substrate. This revealed the thermal conductivity to be similar to the ultralow thermal conductivity of single crystal SnSe, with a value of 0.34 W m–1 K–1 being observed at 313 K

Are There Any Type 2 QSOs? The Case of AXJ0341.4-4453

The X-ray source AXJ0341.4-4453 was described by Boyle et al. as a Type 2 AGN at z = 0.672 based on the absence of broad emission lines in the observed wavelength range 4000-7000 Angstroms. We obtained a new spectrum of AXJ0341.4-4453 extending to 9600 Angstroms which reveals broad Balmer lines and other characteristics of Seyfert 1 galaxies. The FWHM of broad H-beta is at least 1600 km/s, while [O III]5007 has FWHM = 730 km/s. The flux ratio [O III]5007/H-beta = 1. Thus, AXJ0341.4-4453 is by definition a narrow-line Seyfert 1 galaxy, or perhaps a moderately reddened Seyfert 1 galaxy, but it is not a Type 2 QSO. Although examples of the latter have long been sought, particularly in connection with the problem of the X-ray background, there is still virtually no evidence for the existence of any Type 2 QSO among X-ray selected samples.Comment: 4 pages, 3 figures, to appear in MNRA

Evidence-based interventions in dementia: A pragmatic cluster-randomised trial of an educational intervention to promote earlier recognition and response to dementia in primary care (EVIDEM-ED)

Background: The National Dementia Strategy seeks to enhance general practitioners' diagnostic and management skills in dementia. Early diagnosis in dementia within primary care is important as this allows those with dementia and their family care networks to engage with support services and plan for the future. There is, however, evidence that dementia remains under-detected and sub-optimally managed in general practice. An earlier unblinded, cluster randomised controlled study tested the effectiveness of educational interventions in improving detection rates and management of dementia in primary care. In this original trial, a computer decision support system and practice-based educational workshops were effective in improving rates of detecting dementia although not in changing clinical management. The challenge therefore is to find methods of changing clinical management. Our aim in this new trial is to test a customised educational intervention developed for general practice, promoting both earlier diagnosis and concordance with management guidelines.Design/Method: The customised educational intervention combines practice-based workshops and electronic support material. Its effectiveness will be tested in an unblinded cluster randomised controlled trial with a pre-post intervention design, with two arms; normal care versus the educational intervention. Twenty primary care practices have been recruited with the aim of gaining 200 patient participants. We will examine whether the intervention is effective, pragmatic and feasible within the primary care setting. Our primary outcome measure is an increase in the proportion of patients with dementia who receive at least two dementia-specific management reviews per year. We will also examine important secondary outcomes such as practice concordance with management guidelines and benefits to patients and carers in terms of quality of life and carer strain.Discussion: The EVIDEM-ED trial builds on the earlier study but the intervention is different in that it is specifically customised to the educational needs of each practice. If this trial is successful it could have implications for the implementation of the National Dementia Strategy

The discovery of a high redshift type 2 QSO

We report the discovery of a high redshift, narrow emission-line galaxy identified in the optical follow-up of deep ROSAT fields. The object has a redshift of z=2.35 and its narrow emission lines together with its high optical and X-ray luminosity imply that this is a rare example of a type 2 QSO. The intrinsic X-ray absorption is either very low or we are observing scattered flux which does not come directly from the nucleus. The X-ray spectrum of this object is harder than that of normal QSOs, and it is possible that a hitherto unidentified population of similar objects at fainter X-ray fluxes could account for the missing hard component of the X-ray background.Comment: uuencoded compressed postscript. The preprint is also available at http://www.ast.cam.ac.uk/preprint/PrePrint.htm