Gravitationally lensed quasars in Gaia: I. Resolving small-separation lenses

Gaia’s exceptional resolution (FWHM ~ 0.1 arcsec) allows identification and cataloguing of the multiple images of gravitationally lensed quasars. We investigate a sample of 49 known lensed quasars in the Sloan Digital Sky Survey (SDSS) footprint, with image separations less than 2 arcsec, and find that eight are detected with multiple components in the first Gaia data release. In the case of the 41 single Gaia detections, we generally are able to distinguish these lensed quasars from single quasars when comparing Gaia flux and position measurements to those of Pan-STARRS and SDSS. This is because the multiple images of these lensed quasars are typically blended in ground-based imaging and therefore the total flux and a flux-weighted centroid are measured, which can differ significantly from the fluxes and centroids of the individual components detected by Gaia. We compare the fluxes through an empirical fit of Pan-STARRS griz photometry to the wide optical Gaia bandpass values using a sample of isolated quasars. The positional offsets are calculated from a recalibrated astrometric SDSS catalogue. Applying flux and centroid difference criteria to spectroscopically confirmed quasars, we discover four new sub-arcsecond-separation lensed quasar candidates which have two distinct components of similar colour in archival Canada–France–Hawaii Telescope or Hyper Suprime Cam data. Our method based on single Gaia detections can be used to identify the ~1400 lensed quasars with image separation above 0.5 arcsec, expected to have only one image bright enough to be detected by Gaia

Gravitationally lensed quasars in Gaia - II. Discoveryof 24 lensed quasars

We report the discovery, spectroscopic confirmation and preliminary characterisation of 24 gravitationally lensed quasars identified using Gaia observations. Candidates were selected in the Pan-STARRS footprint with quasar-like WISE colours or as photometric quasars from SDSS, requiring either multiple detections in Gaia or a single Gaia detection near a morphological galaxy. The Pan-STARRS grizY images were modelled for the most promising candidates and 60 candidate systems were followed up with the William Herschel Telescope. 13 of the lenses were discovered as Gaia multiples and 10 as single Gaia detections near galaxies. We also discover 1 lens identified through a quasar emission line in an SDSS galaxy spectrum. The lenses have median image separation 2.13 arcsec and the source redshifts range from 1.06 to 3.36. 4 systems are quadruply-imaged and 20 are doubly-imaged. Deep CFHT data reveal an Einstein ring in one double system. We also report 12 quasar pairs, 10 of which have components at the same redshift and require further follow-up to rule out the lensing hypothesis. We compare the properties of these lenses and other known lenses recovered by our search method to a complete sample of simulated lenses to show the lenses we are missing are mainly those with small separations and higher source redshifts. The initial Gaia data release only catalogues all images of ~ 30% of known bright lensed quasars, however the improved completeness of Gaia data release 2 will help find all bright lensed quasars on the sky

The discovery of a five-image lensed quasar at z = 3.34 using PanSTARRS1 and Gaia

We report the discovery, spectroscopic confirmation, and mass modelling of the gravitationally lensed quasar system PS J0630-1201. The lens was discovered by matching a photometric quasar catalogue compiled from Pan-STARRS and WISE photometry to the Gaia DR1 catalogue, exploiting the high spatial resolution of the latter (FWHM $\sim$0.1") to identify the three brightest components of the lens. Follow-up spectroscopic observations with the WHT confirm the multiple objects are quasars at redshift $z_{q}=3.34$. Further follow-up with Keck AO high-resolution imaging reveals that the system is composed of two lensing galaxies and the quasar is lensed into a $\sim$2.8" separation four-image cusp configuration with a fifth image clearly visible, and a 1.0" arc due to the lensed quasar host galaxy. The system is well-modelled with two singular isothermal ellipsoids, reproducing the position of the fifth image. We discuss future prospects for measuring time delays between the images and constraining any offset between mass and light using the faintly detected Einstein arcs associated with the quasar host galaxy

The Development of a Set of Principles for Through-Life Management of Engineering Information

Corporate business models are shifting away from product delivery paradigms to product-service paradigms, where ongoing through-life service support is preeminent. In the UK, a Grand Challenge project (www.kimproject.org) was established to investigate and develop good practice with regard to the design and use of information, knowledge support systems, and business methods necessary for organisations to succeed and profit within this new environment. A key outcome of this work has been the development of a series of principles for through-life management of engineering information, derived from the research insights and experiences of project members in both academia and industry, and supported by detailed explanations and implementation guidance. This report is an approved version of the Principles and their development.This work was undertaken through the “Immortal Information and Through-Life Knowledge Management: Strategies and Tools for the Emerging Product-Service Paradigm” (KIM) project, funded by the UK Engineering and Physical Sciences Research Council (EPSRC) and the Economic and Social Research Council (ESRC), under grant number EP/C534220/1

Sialic Acid Glycobiology Unveils Trypanosoma cruzi Trypomastigote Membrane Physiology.

Trypanosoma cruzi, the flagellate protozoan agent of Chagas disease or American trypanosomiasis, is unable to synthesize sialic acids de novo. Mucins and trans-sialidase (TS) are substrate and enzyme, respectively, of the glycobiological system that scavenges sialic acid from the host in a crucial interplay for T. cruzi life cycle. The acquisition of the sialyl residue allows the parasite to avoid lysis by serum factors and to interact with the host cell. A major drawback to studying the sialylation kinetics and turnover of the trypomastigote glycoconjugates is the difficulty to identify and follow the recently acquired sialyl residues. To tackle this issue, we followed an unnatural sugar approach as bioorthogonal chemical reporters, where the use of azidosialyl residues allowed identifying the acquired sugar. Advanced microscopy techniques, together with biochemical methods, were used to study the trypomastigote membrane from its glycobiological perspective. Main sialyl acceptors were identified as mucins by biochemical procedures and protein markers. Together with determining their shedding and turnover rates, we also report that several membrane proteins, including TS and its substrates, both glycosylphosphatidylinositol-anchored proteins, are separately distributed on parasite surface and contained in different and highly stable membrane microdomains. Notably, labeling for α(1,3)Galactosyl residues only partially colocalize with sialylated mucins, indicating that two species of glycosylated mucins do exist, which are segregated at the parasite surface. Moreover, sialylated mucins were included in lipid-raft-domains, whereas TS molecules are not. The location of the surface-anchored TS resulted too far off as to be capable to sialylate mucins, a role played by the shed TS instead. Phosphatidylinositol-phospholipase-C activity is actually not present in trypomastigotes. Therefore, shedding of TS occurs via microvesicles instead of as a fully soluble form

Change in Composition of the Anopheles Gambiae Complex and its Possible Implications for the Transmission of Malaria and Lymphatic Filariasis in North-Eastern Tanzania.

A dramatic decline in the incidence of malaria due to Plasmodium falciparum infection in coastal East Africa has recently been reported to be paralleled (or even preceded) by an equally dramatic decline in malaria vector density, despite absence of organized vector control. As part of investigations into possible causes for the change in vector population density, the present study analysed the Anopheles gambiae s.l. sibling species composition in north-eastern Tanzania. The study was in two parts. The first compared current species complex composition in freshly caught An. gambiae s.l. complex from three villages to the composition reported from previous studies carried out 2-4 decades ago in the same villages. The second took advantage of a sample of archived dried An. gambiae s.l. complex specimens collected regularly from a fourth study village since 2005. Both fresh and archived dried specimens were identified to sibling species of the An. gambiae s.l. complex by PCR. The same specimens were moreover examined for Plasmodium falciparum and Wuchereria bancrofti infection by PCR. As in earlier studies, An. gambiae s.s., Anopheles merus and Anopheles arabiensis were identified as sibling species found in the area. However, both study parts indicated a marked change in sibling species composition over time. From being by far the most abundant in the past An. gambiae s.s. was now the most rare, whereas An. arabiensis had changed from being the most rare to the most common. P. falciparum infection was rarely detected in the examined specimens (and only in An. arabiensis) whereas W. bancrofti infection was prevalent and detected in all three sibling species. The study indicates that a major shift in An. gambiae s.l. sibling species composition has taken place in the study area in recent years. Combined with the earlier reported decline in overall malaria vector density, the study suggests that this decline has been most marked for An. gambiae s.s., and least for An. arabiensis, leading to current predominance of the latter. Due to differences in biology and vectorial capacity of the An. gambiae s.l. complex the change in sibling species composition will have important implications for the epidemiology and control of malaria and lymphatic filariasis in the study area

Higher education and economic development: the importance of building technological capabilities

Higher education and development has not been a priority of global policy or research funding in recent decades. Yet, since the millennium, Southern governments have become believers in the global knowledge economy and higher education enrolment growth has been phenomenal. In this paper we offer an original account of how higher education institutions contribute to economic development by drawing on evolutionary economics and the national innovation systems approach. This offers distinct advantages in conceptualising higher education's developmental role, through its stress on the importance of education, skills, work, innovation and production for economic development. Using these concepts, we examine how well South African higher education is positioned to contribute to economic development through a consideration of two case studies from astronomy and automotives. These highlight the importance of the intersection between global, national, sectoral and spatial dimensions of the education - economic development relationship. We suggest that dynamics at multiple scalar levels work in complex ways to shape possibilities for development. We argue that such an approach offers a way forward for international education and development thinking about the relationship between education, technological innovation, production and development

Comparison of self-reported health & healthcare utilisation between asylum seekers and refugees: an observational study

<p>Abstract</p> <p>Background</p> <p>Adult refugees and asylum seekers living in Western countries experience a high prevalence of mental health problems, especially post traumatic stress disorder (PTSD), depression and anxiety. This study compares and contrasts the prevalence of health problems, and potential risk factors as well as the utilisation of health services by asylum seekers and refugees in the Irish context.</p> <p>Methods</p> <p>Cross sectional study using validated self reported health status questionnaires of adult asylum seekers (n = 60) and refugees (n = 28) from 30 countries, living in Ireland. Outcome measures included: general health status (SF-36), presence of PTSD symptoms and anxiety/depression symptoms. Data on chronic conditions and pre or post migration stressors are also reported. The two groups are compared for utilisation of the health care system and the use of over the counter medications.</p> <p>Results</p> <p>Asylum seekers were significantly more likely than refugees to report symptoms of PTSD (OR 6.3, 95% CI: 2.2–17.9) and depression/anxiety (OR 5.8, 95% CI: 2.2–15.4), while no significant difference was found in self-reported general health. When adjusted by multivariable regression, the presence of more than one chronic disease (OR 4.0, 95%CI: 1.3–12.7; OR 3.4, 95% CI: 1.2–10.1), high levels of pre migration stressors (OR 3.6, 95% CI: 1.1–11.9; OR 3.3, 95% CI: 1.0–10.4) or post migration stressors (OR 17.3, 95% CI: 4.9–60.8; OR 3.9, 95% CI: 1.2–12.3) were independent predictors of self reported PTSD or depression/anxiety symptoms respectively, however, residence status was no longer significantly associated with PTSD or depression/anxiety. Residence status may act as a marker for other explanatory variables; our results show it has a strong relationship with post migration stressors (χ²= 19.74, df = 1, P < 0.001).</p> <p>In terms of health care utilisation, asylum seekers use GP services more often than refugees, while no significant difference was found between these groups for use of dentists, medication, hospitalisation or mental health services.</p> <p>Conclusion</p> <p>Asylum seekers have a higher level of self reported PTSD and depression/anxiety symptoms compared to refugees. However, residence status appears to act as a marker for post migration stressors. Compared to refugees, asylum seekers utilise GP services more often, but not mental health services.</p

Practices, patients and (im)perfect data - feasibility of a randomised controlled clinical drug trial in German general practices

<p>Abstract</p> <p>Background</p> <p>Randomised controlled clinical (drug) trials supply high quality evidence for therapeutic strategies in primary care. Until now, experience with drug trials in German general practice has been sparse. In 2007/2008, the authors conducted an investigator-initiated, non-commercial, double-blind, randomised controlled pilot trial (HWI-01) to assess the clinical equivalence of ibuprofen and ciprofloxacin in the treatment of uncomplicated urinary tract infection (UTI). Here, we report the feasibility of this trial in German general practices and the implementation of Good Clinical Practice (GCP) standards as defined by the International Conference on Harmonisation (ICH) in mainly inexperienced general practices.</p> <p>Methods</p> <p>This report is based on the experience of the HWI-01 study conducted in 29 German general practices. Feasibility was defined by 1) successful practice recruitment, 2) sufficient patient recruitment, 3) complete and accurate data collection and 4) appropriate protection of patient safety.</p> <p>Results</p> <p>The final practice recruitment rate was 18%. In these practices, 79 of 195 screened UTI patients were enrolled. Recruitment differed strongly between practices (range 0-12, mean 2.8 patients per practice) and was below the recruitment goal of approximately 100 patients. As anticipated, practice nurses became the key figures in the screening und recruitment of patients. Clinical trial demands, in particular for completing symptom questionnaires, documentation of source data and reporting of adverse events, did not agree well with GPs' documentation habits and required support from study nurses. In many cases, GPs and practice staff seemed to be overwhelmed by the amount of information and regulations. No sudden unexpected serious adverse reactions (SUSARs) were observed during the trial.</p> <p>Conclusions</p> <p>To enable drug trials in general practice, it is necessary to adapt the setup of clinical research infrastructure to the needs of GPs and their practice staff. Risk adaption of clinical trial regulations is necessary to facilitate non-commercial comparative effectiveness trials in primary health care.</p> <p>Trial Registration</p> <p>Trial registration number: <a href="http://www.controlled-trials.com/ISRCTN00470468">ISRCTN00470468</a></p

Does the aldosterone: renin ratio predict the efficacy of spironolactone over bendroflumethiazide in hypertension? A clinical trial protocol for RENALDO (RENin-ALDOsterone) study

&lt;p&gt;Background: High blood pressure is an important determinant of cardiovascular disease risk. Treated hypertensives do not attain a risk level equivalent to normotensives. This may be a consequence of suboptimal blood pressure control to which indiscriminate use of antihypertensive drugs may contribute. Indeed the recent ALLHAT[1]study suggests that thiazides should be given first to virtually all hypertensives. Whether this is correct or whether different antihypertensive therapies should be targeted towards different patients is a major unresolved issue, which we address in this study.&lt;/p&gt; &lt;p&gt;The measurement of the ratio of aldosterone: renin is used to identify hypertensive subjects who may respond well to treatment with the aldosterone antagonist spironolactone. It is not known if subjects with a high ratio have aldosteronism or aldosterone-sensitive hypertension is debated but it is important to know whether spironolactone is superior to other diuretics such as bendroflumethiazide in this setting.&lt;/p&gt; &lt;p&gt;Methods/design: The study is a double-blind, randomised, crossover, controlled trial that will randomise 120 hypertensive subjects to 12 weeks treatment with spironolactone 50 mg once daily and 12 weeks treatment with bendroflumethiazide 2.5 mg once daily. The 2 treatment periods are separated by a 2-week washout period. Randomisation is stratified by aldosterone: renin ratio to include equal numbers of subjects with high and low aldosterone: renin ratios.&lt;/p&gt; &lt;p&gt;Primary Objective – To test the hypothesis that the aldosterone: renin ratio predicts the antihypertensive response to spironolactone, specifically that the effect of spironolactone 50 mg is greater than that of bendroflumethiazide 2.5 mg in hypertensive subjects with high aldosterone: renin ratios.&lt;/p&gt; &lt;p&gt;Secondary Objectives – To determine whether bendroflumethiazide induces adverse metabolic abnormalities, especially in subjects with high aldosterone: renin ratios and if baseline renin measurement predicts the antihypertensive response to spironolactone and/or bendrofluazide.&lt;/p&gt; &lt;p&gt;Discussion: The numerous deleterious effects of hypertension dictate the need for a systematic approach for its treatment. In spite of various therapies, resistant hypertension is widely prevalent. Among various factors, primary aldosteronism is an important cause of resistant hypertension and is now more commonly recognised. More significantly, hypertensives with primary aldosteronism are also exposed to various other deleterious effects of excess aldosterone. Hence treating hypertension with specific aldosterone antagonists may be a better approach in this group of patients. It may lead on to better blood pressures with fewer medications.&lt;/p&gt