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A new x-ray spectrometer has been constructed which incorporates a novel large area, low capacitance Si(Li) detector and a low noise JFET (junction field effect transistor) preamplifier. The spectrometer operates at high count Tates without the conventional compromise in energy resolution. For example, at an amplifier peaking time of 1 p.sec and a throughput count rate of 145,000 counts sec-1, the energy resolution at 5.9 keV is 220 eV FWHM. Commercially available spectrometers utilizing conventional geometry Si(Li) detectors with areas equivalent to the new detector have resolutions on the order of 540 eV under the same conditions. Conventional x-ray spectrometers offering high energy resolution must employ detectors with areas one-tenth the size of the new LBL detector (20 mm2 compared with 200 mm2). However, even with the use of the smaller area detectors, the energy resolution of a commercial system is typically limited to approximately 300 eV (again, at 1 μsec and 5.9 keV) due to the noise of the commercially available JFET's. The new large area detector is useful in high count rate applications, but is also useful in the detection of weak photon signals, in which it is desirable to subtend as large an angle of the available photon flux as possible, while still maintaining excellent energy resolution. X-ray fluorescence data from die new spectrometer is shown in comparison to a commercially available system in the analysis of a dilute muhi-element material, and also in conjunction with high count rate synchrotron EXAFS applications.
Background: The association of myasthenia gravis (MG) and inflammatory myositis (IM) is rare and often only one of the diseases is diagnosed. Methods: In this study, we reviewed medical records of patients seen at NMDU from 2004 to 2017 who had diagnosis of concurrent MG and IM. The data is presented descriptively. -Results: We identified 7 patients with MG-IM overlap. Clinical features, laboratory and pathology data of the patients are summarized in Table 1. Conclusions: This is one of the largest case series with MG-IM overlap. It is very important to recognize such association and the different pattern of muscle involvement because therapies may be adjusted to treat both conditions. In patients with thymic pathology, conventional disease modifying agents, IVIG and glucocorticoid in addition to thymoma resection appear to be effective. In patients with refractory MG and myositis who were AChR negative, rituximab may be effective.
In places on the solar surface where longitudinal magnetic fields are detectable using Leighton's photographic technique, spectroheliograms taken in the cores of many Fraunhofer lines show a bright photospheric network similar to, but with finer structure than, the familiar chromospheric network visible on Ca+ K232 spectroheliograms. This paper describes preliminary results of a study of the relation between the photospheric network and its associated magnetic fields.
We report on the analysis of virtual powder-diffraction patterns from serial femtosecond crystallography (SFX) data collected at an X-ray free-electron laser. Different approaches to binning and normalizing these patterns are discussed with respect to the microstructural characteristics which each highlights. Analysis of SFX data from a powder of Pr0.5Ca0.5MnO3 in this way finds evidence of other trace phases in its microstructure which was not detectable in a standard powder-diffraction measurement. Furthermore, a comparison between two virtual powder pattern integration strategies is shown to yield different diffraction peak broadening, indicating sensitivity to different types of microstrain. This paper is a first step in developing new data analysis methods for microstructure characterization from serial crystallography data.
This paper describes the system architecture of a newly constructed radio telescope – the Boolardy engineering test array, which is a prototype of the Australian square kilometre array pathfinder telescope. Phased array feed technology is used to form multiple simultaneous beams per antenna, providing astronomers with unprecedented survey speed. The test array described here is a six-antenna interferometer, fitted with prototype signal processing hardware capable of forming at least nine dual-polarisation beams simultaneously, allowing several square degrees to be imaged in a single pointed observation. The main purpose of the test array is to develop beamforming and wide-field calibration methods for use with the full telescope, but it will also be capable of limited early science demonstrations.
The existence of a stream of tidally stripped stars from the Sagittarius dwarf galaxy demonstrates that the Milky Way is still in the process of accreting mass. More recently, an extensive stream of stars has been uncovered in the halo of the Andromeda galaxy (M31), revealing that it too is cannibalising a small companion. This paper reports the recent observations of this stream, determining its spatial and kinematic properties, and tracing its three-dimensional structure, as well as describing future observations and what we may learn about the Andromeda galaxy from this giant tidal stream.
The Parkes pulsar data archive currently provides access to 144044 data files obtained from observations carried out at the Parkes observatory since the year 1991. Around 105 files are from surveys of the sky, the remainder are observations of 775 individual pulsars and their corresponding calibration signals. Survey observations are included from the Parkes 70 cm and the Swinburne Intermediate Latitude surveys. Individual pulsar observations are included from young pulsar timing projects, the Parkes Pulsar Timing Array and from the PULSE@Parkes outreach program. The data files and access methods are compatible with Virtual Observatory protocols. This paper describes the data currently stored in the archive and presents ways in which these data can be searched and downloaded.
The fishery for Norway lobsters Nephrops norvegicus began in the 1950s and has since become one of the most valuable assets of the Clyde Sea Area. Landings of Nephrops reached a peak of 26001 in 1972. Following a decline in landings up to 1975 there has been a further increase to over 45001 in 1983, valued at £4–5 million. Most of the landings are made by inshore trawlers working from Ayr, Troon, Girvan, Largs, Campbeltown and Tarbert. Recently a small creel fishery has developed in some sea lochs. The abundance of the stock appears to have been maintained; landings per unit of fishing effort have fluctuated without any obvious trend.
Since September, 1979. several aspects of the biology of Nephrops have been studied in an area south of the Little Cumbrae at the north end of the east Arran Basin. Data are presented on the density, size composition, growth rate, reproductive biology and feeding of Nephrops in this area. The results are compared with those obtained for other Nephrops populations, revealing some unusual features of Clyde Nephrops. In the Clyde, densities were lower than in a number of other areas, while growth rate was much higher and animals grew to larger sizes. Sexual maturity was attained at a larger size in Clyde Nephrops and studies of ovary development revealed that considerable numbers of large females did not reproduce annually, in contrast to some other areas. Recent observations suggest that the biological characteristics of Nephrops populations in an area may be influenced by features of the local physical environment such as the particle size distribution and organic carbon content of the sediment. Differences between Clyde Nephrops and those from other areas are discussed in relation to this.
In an attempt to establish a chronology for volcanic neck emplacement and so elucidate petrogenesis, isotopic studies have been carried out on various cumulate inclusions, blocks and megacrysts which occur chiefly in association with tuffs infilling several Scottish vents. K-Ar ages of 13 samples of low-pressure cumulate minerals (biotite, hornblende and pyroxene) from necks in East Fife indicate crystallisation at shallow depth at 314 Ma. U-Pb analyses of zircons are concordant at 318 Ma suggesting they are also members of this suite and their formation is penecontemporaneous with the Namurian volcanic activity which is welldocumented stratigraphically. By 295 Ma crystallisation of anorthoclase megacrysts had been completed, perhaps from the fractionated residuum. An eruption from considerable depth (within the stability field of garnet precipitation) then broke through to the surface bearing high-pressure megacrysts. This penetrated and disrupted the early cumulates carrying them to the surface and producing the diverse vent assemblages. K-Ar dating of basanites suggest that the Duncansby Ness neck in Caithness was emplaced around 270 Ma in the early Permian. For two Fife necks the balance of evidence favours an age of 290 Ma (Stephanian) for this final explosive activity associated with vent formation.
One of the many subjects on which Thomas Charles-Edwards has immeasurably broadened our understanding over the years is that of early Irish legal education. Through his work we have been invited to contemplate not merely what, but how, budding lawyers were being taught in the schools. No tract addresses the issue of instructional method specifically; however, given the traditional understanding of the extant law tracts as textbooks for junior jurists, it seems only reasonable to imagine that one might be able to infer something about this from the texts that remain. Particularly difficult to reconstruct from this distance are the oral aspects of early legal instruction, though one tract in the corpus has always seemed to me especially promising in this respect. Berrad Airechta, an early-eighth-century tract on suretyship and contract (and the first text I ever read with Professor Charles-Edwards thirty years ago at Oxford), is well known among specialists for the large amount of purportedly oral material it contains. Not only is it one of our most important sources for sayings attributed to the traditional oral law known as Fénechas, but at the core of the tract are replicated what purport to be the ritualised oral exchanges used by creditor and debtor in contracting obligations. Equally intriguing are the ten quotations not ascribed to Fénechas but introduced in the text by expressions such as is de asberr, ‘it is regarding this that this is said’, or cid dia nepir, ‘why is this said?’
Early medieval stone sculpture is the most important archaeological evidence we currently have for identifying the process of conversion to Christianity and the development and distribution of ecclesiastical foundations and related sites in Wales before the twelfth century. Moreover, close examination of the sculpture – including quantification, and consideration of its archaeological and historical context, geology, form, function, ornament and inscriptions – also allows us to study it as an important manifestation of material, economic and social investment and consequently to pose other interesting questions concerning cultural contacts, wealth and patronage, the ownership of land and the relationship between secular rulers and the Church.
To date, research on the early medieval sculpture of north-west Wales has tended to focus on the inscribed memorial stones of the fifth to seventh centuries. Though some of the later monuments have been discussed, notably by H. Harold Hughes and C. A. R. Radford, a number were not noted in Nash-Williams's Early Christian Monuments of Wales and several others have come to light more recently. The aim of this paper is to focus on the Viking-Age sculpture of northwest Wales, especially Anglesey, which is broadly datable from the tenth to early twelfth centuries, and to examine the complete range of carved stone monuments, not just the large-scale, free-standing decorated crosses, particularly those at Penmon, which have tended to receive most attention in the past.
Christian iconography is not so plentiful in the post-Roman states of Britain that we can afford to ignore a varied and interesting range of crosses and other motifs from a period when we are otherwise heavily dependent on epigraphic evidence, a tradition that was largely peculiar to the far west and north. The problem is the source: like Dean Swift's island of Laputa, a substantial body of hanging-bowls floats above the cultural landscape of seventh-century Britain. Often labelled ‘Anglo-Saxon’ from their usual find-places in furnished burials in eastern England, considerable ingenuity has been expended in the past in arguing for a Germanic context for the manufacture of these distinctive vessels, despite their late Celtic decoration. Most hanging-bowls are demonstrably not made for or by Germanic owners and in their ornament they bear unique witness to the pretensions, changing tastes and religion of the Celtic patrons for whom most of these luxury items were originally manufactured. The tally of early bowls is now well over 150 and steadily rising through metal-detecting and controlled excavations, but is certainly an underestimate because the parts that survive best are the applied mounts, comprising suspension hooks with a decorated plate, separate appliqués or basal plates attached to the inside or outside of the vessel. Otherwise unrecorded bowl-mounts pass through coin fairs and appear on Internet sale sites.