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Aims: Screening for gestational diabetes mellitus (GDM) may be universal or selective based on risk factors. We audited selective screening with an Oral Glucose Tolerance Test (OGTT). Methods: Clinical and laboratory details of the first 200 women who delivered a baby in 2017 were analysed. Results: Based on national recommendations, 46.5% (n=93) had maternal risk factors (RF) and an additional 6.5% (n=13) had fetal RF. Nine women with RF, for unexplained reasons did not have their OGTT. Of the 95 who had their OGTT, the diagnosis of GDM was made in 27.4% (n=26). The diagnosis of GDM was made in an additional 8 women outside selective screening giving an overall incidence of 17.0%. Discussion: More than half of the women needed to be screened selectively for GDM. Compliance with the national recommendations was incomplete and thus the diagnosis of GDM may be missed even in an academic setting.

資料番号: SA8000206000

Discrete Element Modelling (DEM) is a numerical technique that uses a system of interacting discrete bodies to simulate the movement of material being exposed to external forces. This technique is often used to simulate granular systems; however by adding further elements that inter-connect the bodies, it can be used to simulate the deformation of a large volume of material. This method has precedent for use in the Earth Sciences and recently, with the increase of available computing power, it has been put to good use simulating the evolution of extensional faults in large scale crustal experiments that involve over half a million individual spherical bodies. An interactive environment that provides high quality rendering is presented, showing that interactivity is key in allowing the intelligent application of visualization methods such as colour-mapping and visibility thresholds in order to extract fault information from a geological DEM. It is also shown that glyph representation alone is not sufficient to provide full insight into the complex three dimensional geometries of the faults found within the model. To overcome this, a novel use of the MetaBall method is described, which results in implicit surface representations of sphere sub-sets. The surfaces produced are shown to provide greater insight into the faults found within the data but also raise questions as to their meaning.

Within computer science, reusability of specific modular software components is generally accepted as best practice. Simulation techniques such as Discrete Element Modelling (DEM) rely on the well defined problems of Newtonian physics, and while differences exist in the methods defined to compute solutions to these problems, each method follows the same basic set of premises. Recently, libraries termed Physics Engines (PE) have been released that are designed to solve physics based problems. This paper considers the features of a range PEs and explores whether the techniques and design methodologies can be applicable to the design and implementation of a working simulation. The NVIDIA PhysX engine has been utilised in a practical DEM implementation to simulate the evolution of extensional fault systems in rock. Through understanding the general processing pipeline implemented by a PE, obvious similarities with a range of DEM implementations has became apparent. Discussed are areas that are compatible and also areas within the PE that have been proved unsuited to large scale DEM simulation. It is shown that current versions of PEs may not provide access to techniques giving high enough numerical accuracy for certain applications, but the basic premise of an easy to use and highly optimised library, designed to allow researchers to construct complex simulation scenarios is compelling.

Within computer science, reusability of specific modular software components is generally accepted as best practice. Simulation techniques such as Discrete Element Modelling (DEM) rely on the well defined problems of Newtonian physics, and while differences exist in the methods defined to compute solutions to these problems, each method follows the same basic set of premises. Recently, libraries termed Physics Engines (PE) have been released that are designed to solve physics based problems. This paper considers the features of a range PEs and explores whether the techniques and design methodologies can be applicable to the design and implementation of a working simulation. The NVIDIA PhysX engine has been utilised in a practical DEM implementation to simulate the evolution of extensional fault systems in rock. Through understanding the general processing pipeline implemented by a PE, obvious similarities with a range of DEM implementations has became apparent. Discussed are areas that are compatible and also areas within the PE that have been proved unsuited to large scale DEM simulation. It is shown that current versions of PEs may not provide access to techniques giving high enough numerical accuracy for certain applications, but the basic premise of an easy to use and highly optimised library, designed to allow researchers to construct complex simulation scenarios is compelling.

Note: Accepted for publication in The Astrophysical Journal., 資料番号: SA8000384000

Recently, software libraries known as physics engines have begun to gain interest within the computing communities. They are designed primarily for use within the computer game industry but also currently find credence within real-time animation and robotics simulation. The technical requirements of a Discrete Element Model (DEM) are markedly similar to that of a gaming rigid body problem. A DEM needs to calculate which elements are in contact and integrate forces in time to avoid inter-body penetration accordingly. The contact detection techniques utilised in a physics engine are relatively complex and as a result, many DEM simulations do not make use of these optimised techniques. Physics engines provide a well documented and maintained software library upon which a researcher could build a complex rigid body simulation such as a DEM. This also has the effect that DEM simulations that utilise a known physics engine are being calculated using standardised code, something which is considered best practice amongst the computing community when dealing with well defined algorithms. This paper discusses the suitability of the modern physics engine architecture for calculating a DEM. It also details a novel distributed parallelisation technique to allow a physics engine to be used to calculate a DEM with more elements than the majority of current physics engines will allow. The technique is described and a pictorial example given.

Discrete Element Modelling (DEM) is a technique used widely throughout science and engineering. It offers a convenient method with which to numerically simulate a system prone to developing discontinuities within its structure. Often the technique gets overlooked as designing and implementing a model on a scale large enough to be worthwhile can be both time consuming and require specialist programming skills. Currently there are a few notable efforts to produce homogenised software to allow researchers to quickly design and run DEMs with in excess of 1 million elements. However, these applications, while open source, are still complex in nature and require significant input from their original publishers in order for them to include new features as a researcher needs them. Recently software libraries notably from the computer gaming and graphics industries, known as physics engines, have emerged. These are designed specifically to calculate the physical movement and interaction of a system of independent rigid bodies. They provide conceptual equivalents of real world constructions with which an approximation of a realistic scenario can be quickly built. This paper presents a method to utilise the most notable of these engines, NVIDIA's PhysX, to produce a parallelised geological DEM capable of supporting in excess of a million elements.

著者人数: 18名, Note: Accepted for publication in The Astrophysical Journal (Letters), 資料番号: SA8000434000

著者人数: 11名, Note: Presented at Georgia State University Conference on "Variability of Active Galactic Nuclei", May 2-4, 1990. Georgia State University in Atlanta., 資料番号: SA8000441000

著者人数: 15名, Note: Accepted for publication in The Astrophysical Journal on July 24, 1990. To appear in the February 1, 1991 issue., 資料番号: SA8000443000

XMM Newton observations of five high-luminosity radio-quiet QSOs (Q 0144-3938, UM 269, PG 1634+706, SBS 0909+532 and PG 1247+267) are presented. Spectral energy distributions were calculated from the XMM-Newton EPIC (European Photon Imaging Camera) and OM (Optical Monitor) data, with bolometric luminosities estimated in the range from 7 x 10^45 to 2 x 10^48 erg s^-1 for the sample, peaking in the UV. At least four of the QSOs show a similar soft excess, which can be well modelled by either one or two blackbody components, in addition to the hard X-ray power-law. The temperatures of these blackbodies (~100-500 eV) are too high to be direct thermal emission from the accretion disc, so Comptonization is suggested. Two populations of Comptonizing electrons, with different temperatures, are needed to model the broad-band spectrum. The hotter of these produces what is seen as the hard X-ray power-law, while the cooler (~0.25-0.5 keV) population models the spectral curvature at low energies. Only one of the QSOs shows evidence for an absorption component, while three of the five show neutral iron emission. Of these, PG 1247+267 seems to have a broad line (EW ~ 250 eV), with a strong, associated reflection component (R ~ 2), measured out to 30 keV in the rest frame of the QSO. Finally, it is concluded that the X-ray continuum shape of AGN remains essentially constant over a wide range of black hole mass and luminosity., Comment: 12 pages, 6 figures, accepted for publication in MNRAS

XMM-Newton observations of seven QSOs are presented and the EPIC spectra analysed. Five of the AGN show evidence for Fe K-alpha emission, with three being slightly better fitted by lines of finite width; at the 99 per cent level they are consistent with being intrinsically narrow, though. The broad-band spectra can be well modelled by a combination of different temperature blackbodies with a power-law, with temperatures between kT ~ 100-300 eV. On the whole, these temperatures are too high to be direct thermal emission from the accretion disc, so a Comptonization model was used as a more physical parametrization. The Comptonizing electron population forms the soft excess emission, with an electron temperature of ~ 120-680 eV. Power-law, thermal plasma and disc blackbody models were also fitted to the soft X-ray excess. Of the sample, four of the AGN are radio-quiet and three radio-loud. The radio-quiet QSOs may have slightly stronger soft excesses, although the electron temperatures cover the same range for both groups., Comment: 13 pages, 7 figures, accepted for publication in MNRAS

The X-ray spectra of serendipitously observed AGN in the XMM-Newton fields of Mrk 205 and QSO 0130-403 are analysed. The sample consists of 23 objects, none of which is detected at radio frequencies, with a median X-ray luminosity of ~ 4 x 10^44 erg s^-1 and redshifts ranging from ~0.1 to just over 3. The mean photon index was found to be 1.89 +/- 0.04. In contrast to past ASCA and ROSAT observations of high-redshift radio-loud quasars, we find little evidence for excess intrinsic absorption in these radio-quiet objects, with only three sources requiring a column density in excess of the Galactic value. Comparing the measured spectral indices over the redshift range, we also find there is no X-ray spectral evolution of QSOs with time, up to redshift 3. Within the sample there is no evidence for evolution of the optical to X-ray spectral index, alpha-ox, with redshift, the mean value being -1.66 +/- 0.04. However, upon comparing the values from the Bright Quasar Survey at low redshift (z < 0.5) and high redshift QSOs detected by Chandra (z > 4), a slight steepening of alpha-ox is noted for the more distant objects. In most of the sources there is no significant requirement for a soft excess, although a weak thermal component (< 10% of Lx) cannot be excluded. There is an indication of spectral flattening (by delta gamma=0.2) at higher energies (> 3 keV, QSO rest frame) for the sample as a whole. This is consistent with the presence of a Compton reflection component in these radio-quiet AGN, with the scattering medium (such as an accretion disc or molecular torus) occupying a solid angle of 2 pi steradians to the X-ray source., 10 pages, 10 figures; accepted by MNRAS

Since their identification with cosmological distances, Gamma-ray bursts (GRBs) have been recognised as the most energetic phenomena in the Universe, with an isotropic burst energy as high as 10^54 ergs. However, the progenitors responsible for the bursts remain elusive, favoured models ranging from a neutron star binary merger, to the collapse of a massive star. Crucial to our understanding of the origins of GRBs is the study of the afterglow emission, where spectroscopy can reveal details of the environment of the burst. Here we report on an XMM-Newton observation of the X-ray afterglow of GRB 011211. The X-ray spectrum reveals evidence for emission lines of Magnesium, Silicon, Sulphur, Argon, Calcium, and possibly Nickel, arising in enriched material with an outflow velocity of order 0.1c. This is the first direct measurement of outflowing matter in a gamma ray burst. The observations strongly favour models where a supernova explosion from a massive stellar progenitor precedes the burst event and is responsible for the outflowing matter., Comment: 13 pages, including figures. Published in Nature (April 4th issue)

The bright blazar Mkn 421 has been observed four times for uninterrupted durations of ~ 9 - 13 hr during the performance verification and calibration phases of the XMM-Newton mission. The source was strongly variable in all epochs, with variability amplitudes that generally increased to higher energy bands. Although the detailed relationship between soft (0.1 - 0.75 keV) and hard (2 - 10 keV) band differed from one epoch to the next, in no case was there any evidence for a measurable interband lag, with robust upper limits of $| \tau | < 0.08 $ hr in the best-correlated light curves. This is in conflict with previous claims of both hard and soft lags of ~1 hr in this and other blazars. However, previous observations suffered a repeated 1.6 hr feature induced by the low-Earth orbital period, a feature that is not present in the uninterrupted XMM-Newton data. The new upper limit on $|\tau|$ leads to a lower limit on the magnetic field strength and Doppler factor of $ B \delta^{1/3} \gs 4.7 $ G, mildly out of line with the predictions from a variety of homogeneous synchrotron self-Compton emission models in the literature of $ B \delta^{1/3} = 0.2 - 0.8 $ G. Time-dependent spectral fitting was performed on all epochs, and no detectable spectral hysteresis was seen. We note however that the source exhibited significantly different spectral evolutionary behavior from one epoch to the next, with the strongest correlations in the first and last and an actual divergance between soft and hard X-ray bands in the third. This indicates that the range of spectral variability behavior in Mkn 421 is not fully described in these short snippets; significantly longer uninterrupted light curves are required, and can be obtained with XMM-Newton., Comment: 21 pages, 4 figures, accepted for ApJ, scheduled for August 1, 2002

We present the first results on the identifications of a medium sensitivity survey (X-ray flux limit 2 × 10-14 erg cm-2s-1 in the 0.5-4.5 keV band) at high galactic latitude (|b| > 20°) carried out with the XMM-Newton X-ray observatory within the AXIS observing programme. This study is being conducted as part of the XMM-Newton Survey Science Centre activities towards the identification of the sources in the X-ray serendipitous sky survey. The sample contains 29 X-ray sources in a solid angle of 0.26 deg2 (source density 113±21 sources deg-2), out of which 27 (93%) have been identified. The majority of the sources are broad-line AGN (19), followed by narrow emission line X-ray emitting galaxies (6, all of which turn out to be AGN), 1 nearby non-emission line galaxy (NGC 4291) and 1 active coronal star. Among the identified sources we find 2 broad-absorption line QSOs (z ∼ 1.8 and z ∼ 1.9), which constitute ∼10% of the AGN population at this flux level, similar to optically selected samples. Identifications of a further 10 X-ray sources fainter than our survey limit are also presented., XB, FJC, MTC and SM acknowledge financial support by the Spanish MCYT under project AYA2000-1690. RDC and TM acknowledge partial financial support by the Italian Space Agency (ASI) and by the MURST (Cofin00-32-36). This project was supported by the DLR under grants 50 OR 9908 0 (GPS) and 50 OX 9801 3 (HB).

著者人数: 13名, Note: submitted to Nature on 23 Dec. 1987., 資料番号: SA8000514000

著者人数: 11名, Note: accepted for publication in Astrophysical Journal on Sept. 5, 1989., 資料番号: SA8000473000

Accepted: 1989-04-28, 資料番号: SA1001402000

著者人数：17名, Accepted: 1989-02-23, 資料番号: SA1001404000

The XMM-Newton observatory has the largest collecting area flown so far for an X-ray imaging system, resulting in a very high sensitivity over a broad spectral range. In order to exploit fully these performances, a very accurate calibration of the XMM-Newton instruments is required, and has led to an extensive ground and flight calibration program. We report here on the current status of the EPIC/MOS cameras calibrations, highlighting areas for which a reasonably good accuracy has been achieved, and noting points where further work is needed., 7 pages, 10 figures, to appear in the Proceedings of the Symposium `New Visions of the X-ray Universe in the XMM-Newton and Chandra era', 26-30 November 2001, ESTEC, Noordwijk, The Netherlands

XEUS is the potential successor to ESA's XMM-Newton X-ray observatory and is being proposed in response to the Cosmic Vision 2015-2025 long term plan for ESA's Science Programme. A new mission configuration was developed in the last year, accommodating the boundary conditions of a European-led mission with a formation-flying mirror and detector spacecraft in L2 with a focal length of 35m and an effective area of >5 m2 at 1 keV. Here the new capabilities are compared with the key scientific questions presented to the Cosmic Vision exercise: the evolution of large scale structure and nucleosynthesis, the co-evolution of supermassive black holes and their host galaxies, and the study of matter under extreme conditions.