The WFCAM Science Archive Hambly, N. C.; Collins, R. S.; Cross, N. J. G. ...
Monthly notices of the Royal Astronomical Society,
02/2008, Letnik:
384, Številka:
2
Journal Article
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We describe the WFCAM Science Archive, which is the primary point of access for users of data from the wide-field infrared camera WFCAM on the United Kingdom Infrared Telescope (UKIRT), especially ...science catalogue products from the UKIRT Infrared Deep Sky Survey. We describe the database design with emphasis on those aspects of the system that enable users to fully exploit the survey data sets in a variety of different ways. We give details of the database-driven curation applications that take data from the standard nightly pipeline-processed and calibrated files for the production of science-ready survey data sets. We describe the fundamentals of querying relational databases with a set of astronomy usage examples, and illustrate the results.
Cerebrospinal fluid (CSF) biomarkers are increasingly being used to support a diagnosis of Alzheimer's disease (AD). Their clinical utility for differentiating AD from non-AD neurodegenerative ...dementias, such as dementia with Lewy bodies (DLB) or frontotemporal dementia (FTD), is less well established. We aimed to determine the diagnostic utility of an extended panel of CSF biomarkers to differentiate AD from a range of other neurodegenerative dementias.
We used immunoassays to measure conventional CSF markers of amyloid and tau pathology (amyloid beta (Aβ)1-42, total tau (T-tau), and phosphorylated tau (P-tau)) as well as amyloid processing (AβX-38, AβX-40, AβX-42, soluble amyloid precursor protein (sAPP)α, and sAPPβ), large fibre axonal degeneration (neurofilament light chain (NFL)), and neuroinflammation (YKL-40) in 245 patients with a variety of dementias and 30 controls. Patients fulfilled consensus criteria for AD (n = 156), DLB (n = 20), behavioural variant frontotemporal dementia (bvFTD; n = 45), progressive non-fluent aphasia (PNFA; n = 17), and semantic dementia (SD; n = 7); approximately 10% were pathology/genetically confirmed (n = 26). Global tests based on generalised least squares regression were used to determine differences between groups. Non-parametric receiver operating characteristic (ROC) curves and area under the curve (AUC) analyses were used to quantify how well each biomarker discriminated AD from each of the other diagnostic groups (or combinations of groups). CSF cut-points for the major biomarkers found to have diagnostic utility were validated using an independent cohort which included causes of AD (n = 104), DLB (n = 5), bvFTD (n = 12), PNFA (n = 3), SD (n = 9), and controls (n = 10).
There were significant global differences in Aβ1-42, T-tau, T-tau/Aβ1-42 ratio, P-tau-181, NFL, AβX-42, AβX-42/X-40 ratio, APPα, and APPβ between groups. At a fixed sensitivity of 85%, AβX-42/X-40 could differentiate AD from controls, bvFTD, and SD with specificities of 93%, 85%, and 100%, respectively; for T-tau/Aβ1-42 these specificities were 83%, 70%, and 86%. AβX-42/X-40 had similar or higher specificity than Aβ1-42. No biomarker or ratio could differentiate AD from DLB or PNFA with specificity > 50%. Similar sensitivities and specificities were found in the independent validation cohort for differentiating AD and other dementias and in a pathology/genetically confirmed sub-cohort.
CSF AβX-42/X-40 and T-tau/Aβ1-42 ratios have utility in distinguishing AD from controls, bvFTD, and SD. None of the biomarkers tested had good specificity at distinguishing AD from DLB or PNFA.
Recent observations from the Hinode and Solar Dynamics Observatory spacecraft have provided major advances in understanding the heating of solar active regions (ARs). For ARs comprising many magnetic ...strands or sub-loops heated by small, impulsive events (nanoflares), it is suggested that (i) the time between individual nanoflares in a magnetic strand is 500-2000 s, (ii) a weak 'hot' component (more than 106.6 K) is present, and (iii) nanoflare energies may be as low as a few 1023 ergs. These imply small heating events in a stressed coronal magnetic field, where the time between individual nanoflares on a strand is of order the cooling time. Modelling suggests that the observed properties are incompatible with nanoflare models that require long energy build-up (over 10 s of thousands of seconds) and with steady heating.
Natural capital and ecosystem service concepts are embodied in the ecosystems approach to sustainable development, which is a framework being consistently adopted by decision making bodies ranging ...from national governments to the United Nations. In the Millennium Ecosystem Assessment soils are given the vital role of a supporting service, but many of the other soil goods and services remain obscured. In this review we address this using and earth-system approach, highlighting the final goods and services soils produce, in a stock-fund, fund-service model of the pedosphere. We also argue that focusing on final goods and services will be counterproductive in the long run and emphasize that final goods and services are derived from an ecosystem supply chain that relies on ecological infrastructure. We propose that an appropriate ecosystems framework for soils should incorporate soil stocks (natural capital) showing their contribution to stock-flows and emergent fund-services as part of the supply chain. By so doing, an operational ecosystems concept for soils can draw on much more supporting data on soil stocks as demonstrated in a case study with soils data from England and Wales showing stocks, gaps in monitoring and drivers of change. Although the focus of this review is on soils, we believe the earth-system approach and principles of the ecosystem supply chain are widely applicable to the ecosystems approach and bring clarity in terms of where goods and services are derived from.
► We critically review natural capital and ecosystem service concepts for soil science. ► We present a new soil framework based on the stock-flow, fund-service concepts and the ecosystem supply chain. ► We identify explicit soil provisioning goods and emergent ecosystem services soils provide. ► We present a synthesis of soil data for England and Wales within the soil ecosystem service framework.
A new gravitational wave verification source Kilic, Mukremin; Brown, Warren R; Gianninas, A ...
Monthly notices of the Royal Astronomical Society. Letters,
10/2014, Letnik:
444, Številka:
1
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We report the discovery of a detached 20-min orbital period binary white dwarf (WD). WD 0931+444 (SDSS J093506.93+441106.9) was previously classified as a WD + M dwarf system based on its optical ...spectrum. Our time-resolved optical spectroscopy observations obtained at the 8 m Gemini and 6.5 m MMT reveal peak-to-peak radial velocity variations of ≈400 km s−1 every 20 min for the WD, but no velocity variations for the M dwarf. In addition, high-speed photometry from the McDonald 2.1 m telescope shows no evidence of variability nor evidence of a reflection effect. An M dwarf companion is physically too large to fit into a 20 min orbit. Thus, the orbital motion of the WD is almost certainly due to an invisible WD companion. The M dwarf must be either an unrelated background object or the tertiary component of a hierarchical triple system. WD 0931+444 contains a pair of WDs, a 0.32 M⊙ primary and a ≥0.14 M⊙ secondary, at a separation of ≥0.19 R⊙. After J0651+2844, WD 0931+444 becomes the second shortest period detached binary WD currently known. The two WDs will lose angular momentum through gravitational wave radiation and merge in ≤9 Myr. The log h ≃ −22 gravitational wave strain from WD 0931+444 is strong enough to make it a verification source for gravitational wave missions in the milli-Hertz frequency range, e.g. the evolved Laser Interferometer Space Antenna (eLISA), bringing the total number of known eLISA verification sources to nine.
There is general agreement that, after initial processing in unimodal sensory cortex, the processing pathways for spoken and written language converge to access verbal meaning. However, the existing ...literature provides conflicting accounts of the cortical location of this convergence. Most aphasic stroke studies localize verbal comprehension to posterior temporal and inferior parietal cortex (Wernicke's area), whereas evidence from focal cortical neurodegenerative syndromes instead implicates anterior temporal cortex. Previous functional imaging studies in normal subjects have failed to reconcile these opposing positions. Using a functional imaging paradigm in normal subjects that used spoken and written narratives and multiple baselines, we demonstrated common activation during implicit comprehension of spoken and written language in inferior and lateral regions of the left anterior temporal cortex and at the junction of temporal, occipital, and parietal cortex. These results indicate that verbal comprehension uses unimodal processing streams that converge in both anterior and posterior heteromodal cortical regions in the left temporal lobe.
Accumulating evidence in humans and non-human primates implicates the posterior superior temporal plane (STP) in the processing of both auditory spatial information and vocal sounds. Such evidence is ...difficult to reconcile with existing accounts of the primate auditory brain. We propose that the posteromedial STP generates sequenced auditory representations by matching incoming auditory information with stored templates. These sequenced auditory representations are subsequently used to constrain motor responses. We argue for a re-assessment of the much-debated dorsal auditory pathway in terms of its generic behavioral role as an auditory ‘do’ pathway.
The First Data Release (DR1) of the United Kingdom Infrared Telescope Infrared Deep Sky Survey (UKIDSS) took place on 2006 July 21. The UKIDSS is a set of five large near-infrared surveys, covering a ...complementary range of areas, depths and Galactic latitudes. The DR1 is the first large release of survey-quality data from the UKIDSS and includes 320 deg2 of multicolour data to (Vega) K= 18, complete (depending on the survey) in three to five bands from the set ZYJHK, together with 4 deg2 of deep JK data to an average depth K= 21. In addition, the release includes a similar quantity of data with incomplete filter coverage. In JHK, in regions of low extinction, the photometric uniformity of the calibration is better than 0.02 mag in each band. The accuracy of the calibration in ZY remains to be quantified, and the same is true of JHK in regions of high extinction. The median image full width at half-maximum across the data set is 0.82 arcsec. We describe changes since the Early Data Release in the implementation, pipeline and calibration, quality control, and archive procedures. We provide maps of the areas surveyed, and summarize the contents of each of the five surveys in terms of filters, areas and depths. The DR1 marks completion of 7 per cent of the UKIDSS seven-year goals.
ABSTRACT
When modelling strong gravitational lenses, i.e. where there are multiple images of the same source, the most widely used parametrization for the mass profile in the lens galaxy is the ...singular power-law model ρ(r)∝r−γ. This model may be insufficiently flexible for very accurate work, for example, measuring the Hubble constant based on time delays between multiple images. Here, we derive the lensing properties – deflection angle, shear, and magnification – of a more adaptable model where the projected mass surface density is parametrized as a continuous two-dimensional broken power law (2DBPL). This elliptical 2DBPL model is characterized by power-law slopes t1 and t2 either side of the break radius θB. The key to the 2DBPL model is the derivation of the lensing properties of the truncated power-law (TPL) model, where the surface density is a power law out to the truncation radius θT and zero beyond. This TPL model is also useful by itself. We create mock observations of lensing by a TPL profile where the images form outside the truncation radius, so there is no mass in the annulus covered by the images. We then show that the slope of the profile interior to the images may be accurately recovered for lenses of moderate ellipticity. This demonstrates that the widely held notion that lensing measures the slope of the mass profile in the annulus of the images, and is insensitive to the mass distribution at radii interior to the images, is incorrect.
We measure the mass density profile of the lens galaxy in the Einstein ring system 0047-2808 using our semilinear inversion method developed in an earlier paper. By introducing an adaptively gridded ...source plane, we are able to eliminate the need for regularization of the inversion. This removes the problem of a poorly defined number of degrees of freedom, encountered by inversion methods that employ regularization, and so allows a proper statistical comparison between models. We confirm previous results indicating that the source is double and that a power-law model gives a significantly better fit than the singular isothermal ellipsoid model. We measure a slope a = 2.11 c 0.04. We find, furthermore, than a dual-component constant M/L baryonic+dark halo model gives a significantly better fit than the power-law model, at the 99.7% confidence level. The inner logarithmic slope of the dark halo profile is found to be 0.87 super(+) sub(-) super(0) sub(0) super(.) sub(.) super(6) sub(6) super(9) sub(1) (95% CL), consistent with the predictions of cold dark matter simulations of structure formation. We determine an unevolved B-band mass-to-light ratio for the baryons (only) of 3.05 super(+) sub(-) super(0) sub(0) super(.) sub(.) super(5) sub(9) super(3) sub(0) h sub(65) M sub( )/L sub(B ) (95% CL). This is the first measurement of the baryonic M/L of a single galaxy by purely gravitational lens methods. The baryons account for 65 super(+) sub(-) super(1) sub(1) super(0) sub(8)% (95% CL) of the total projected mass, or, assuming spherical symmetry, 84 super(+) sub(-) super(1) sub(2) super(2) sub(4)% (95% CL) of the total three-dimensional mass within the mean radius of 1".16 (7.5 h super(-) sub(6) super(1) sub(5) kpc) traced by the ring. Finally, at the level of >3 s, we find that the halo mass is rounder than the baryonic distribution and that the two components are offset in orientation from one another.
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