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Existing rolling mills entering the markets for high quality steel may be limited by their descaling systems installed in terms of pressure and flow rate. In addition to the potential for optimizations of existing systems, the potential for optimization of the nozzle design itself has now been fully utilized in order to maximize the impact at a given water flow and pressure. New design methods and production technologies have been applied.
Vagus nerve stimulation (VNS) therapy is associated with a decrease in seizure frequency in partial-onset seizure patients. Initial trials suggest that it may be an effective treatment, with few side-effects, for intractable depression.
An open, uncontrolled European multi-centre study (D03) of VNS therapy was conducted, in addition to stable pharmacotherapy, in 74 patients with treatment-resistant depression (TRD). Treatment remained unchanged for the first 3 months; in the subsequent 9 months, medications and VNS dosing parameters were altered as indicated clinically.
The baseline 28-item Hamilton Depression Rating Scale (HAMD-28) score averaged 34. After 3 months of VNS, response rates (⩾50% reduction in baseline scores) reached 37% and remission rates (HAMD-28 score <10) 17%. Response rates increased to 53% after 1 year of VNS, and remission rates reached 33%. Response was defined as sustained if no relapse occurred during the first year of VNS after response onset; 44% of patients met these criteria. Median time to response was 9 months. Most frequent side-effects were voice alteration (63% at 3 months of stimulation) and coughing (23%).
VNS therapy was effective in reducing severity of depression; efficacy increased over time. Efficacy ratings were in the same range as those previously reported from a USA study using a similar protocol; at 12 months, reduction of symptom severity was significantly higher in the European sample. This might be explained by a small but significant difference in the baseline HAMD-28 score and the lower number of treatments in the current episode in the European study.
Nickel-titanium (NiTi) shape memory alloys undergo relatively large recoverable inelastic deformations via a stress-induced martensitic phase transformation. The nanoindentation experimental results presented in this study are the first to show evidence of discrete forward and reverse stress-induced thermoelastic martensitic transformations in nanometer scaled volumes of material. Shape recovery due to indentation, followed by subsequent heating, is demonstrated for indents depths in the sub 10 nm range via atomic force microscopy. It is also shown that the local material structure can be utilized to modify transformation behavior at nanometer scales, yielding insight into the nature of stress-induced martensitic phase transformations at small scales and providing opportunity for the design of nanometer sized NiTi actuators.
An understanding of genetic variation and structure of pest populations has the potential to improve the efficiency of measures to control them. Genetic analysis was undertaken at five microsatellite loci in four native Australian and 14 introduced New Zealand populations of the common brushtail possum Trichosurus vulpecula in order to document these parameters. Genetic variation in New Zealand populations, and phylogenetic relationships among Australian and New Zealand populations, were largely predicted by the recorded introduction history. Populations on the two main islands of New Zealand had only slightly lower genetic diversity than did Australian populations, except that allelic richness on the South Is. was significantly lower. Diversity was higher in North Is. than in South Is. populations (although not significantly so) and mainland New Zealand populations as a group were significantly more diverse than offshore islands that represented secondary population size bottlenecks. In phylogenetic analyses South Is. and offshore island populations grouped with Tasmania, while North Is. populations grouped either with mainland Australia or were intermediate between the two Australian sources. This scheme was supported by admixture coefficients showing that North and South Is./offshore island populations were largely mainland Australian and Tasmanian in origin, respectively. Population structure differed markedly between the North and South Islands: populations were typically more genetically differentiated on the former than the latter, which also showed significant isolation-by-distance. Substantial linkage disequilibrium in most sampled New Zealand but no Australian population between microsatellite loci Tv16 and Tv27 suggests they may be physically linked.
By the middle of the nineteenth century, the characterization of the big city as evil incarnate – a veritable latter-day Sodom – had achieved the status of national myth in both the United States and Britain, and had become a popular theme for journalists, novelists, and playwrights alike. John Frick examines this phenomenon – what came to be known as the ‘wicked city motif’ – as it manifested itself on the antebellum American stage. Originating in the urbanization of the eighteenth-century gothic novel and the French feuilleton roman and coalescing in Eugène Sue's Les Mystères de Paris and G. W. M. Reynolds's The Mysteries of London, the city mysteries narrative successfully negotiated the unstable border between the public and private spheres to examine the depravity and danger of the modern metropolis. Disseminated through populist politics, sensationalized journalism, popular fiction, and – the focus here – dramatic renderings, the apocalyptic vision of the modern city with its inexplicable and impenetrable secrets became commonplace in the 1840s and 1850s. John Frick is Professor of Theatre and American Studies at the University of Virginia and teaches in the M.Litt. program at Mary Baldwin College. His most recent book, Theatre, Culture, and Temperance Reform in Nineteenth-Century America, was published by Cambridge University Press in 2003.
I disagree with several of Chow's traditional
descriptions and justifications of null hypothesis testing:
(1) accepting the null hypothesis whenever p > .05;
(2) random sampling from a population; (3) the frequentist
interpretation of probability; (4) having the null hypothesis
generate both a probability distribution and a complement
of the desired conclusion; (5) assuming that researchers must
fix their sample size before performing their study.
Aerogels are a unique class of materials possessing an open-cell structure with ultrafine cells/pores (<100nm), high surface area (400–1100 m2/g), and a solid matrix composed of interconnected particles, fibers, or platelets with characteristic dimensions of 10nm. Although monolithic aerogels are ideal candidates for many applications (e.g. transparent window insulation), current processing methods have limited their introduction into the commercial marketplace. Our research focuses on the formation of resorcinol-formaldehyde (RF) aerogel microspheres which offer an attractive alternative to monolith production. An inverse emulsion polymerization is used to produce these spherical gel particles which undergo solvent exchange followed by supercritical drying with carbon dioxide. This process yields aerogel microspheres (10–80μ diameter) which can be used as loosely packed powders, compression molded into nearnet shapes using a polymer binder, or used as additives in conventional foaming operations to produce new aerogel composites with superior thermal properties. The emulsification procedure, thermal characterization, mechanical properties, and potential applications of RF aerogel microspheres will be discussed.
In the past several Wolf–Rayet stars have been investigated photometrically by different authors to search for fast pulsations. So far all results were negative. However, in 1992 Blecha, Schaller & Maeder published a 627sec period with a semi–amplitude of about 2.5mmag for the Southern Wolf–Rayet star WR40 (HD96548).
An investigation of the stability properties of stellar models describing massive stars is motivated observationally by the necessity to explain the observed Humphreys - Davidson (HD) limit and the variability of the most massive stars known, i.e. the existence of luminous blue variables (LBVs). Theoretically, a determination of the upper mass limit for stable stellar objects together with its physical explanation and interpretation is of fundamental interest.
All recently completed controlled two-year studies on intermittent, early neuroleptic intervention treatment have failed to compare favourably with studies on maintenance treatment concerning relapse prevention. The reason for this failure is still unclear. Therefore the implicit, but as yet unproven, hypothesis that a relapse can be predicted from prodromal symptoms was tested from the perspective of our German multicentre study. Results demonstrate that this is not the case. Possible reasons for and clinical implications of this negative finding are discussed.
This paper reviews the current status of the Grimsel radionuclide migration experiment, with especial reference to the advances of the last four years. Details are provided on the unusually extensive support programme and the general philosophy of undertaking such a large and costly field experiment.
The occurrence and quantitative properties of Seyfert 1 and Seyfert 2 galaxies as a function of the galaxy environment have been studied in a systematic way. For this investigation we have selected from the Catalogue of Quasars and Active Nuclei (Veron & Veron, 1989) all Seyfert galaxies with the following properties:
(i) mV ≤ 15,
(ii) listed classification as Sey 1, Sey 2, or Sey 3,
(iii) vrad ≤ 20000 km s-1.
This results in a sample size of 242 Seyfert galaxies. For all these objects their galaxy environment has been inspected on POSS and ESO/SRC plates.
The vicinity of each sample Seyfert galaxy was searched for companion galaxies out to at least 0.5 Mpc. Lacking redshift information we adopted as a companion galaxy any galaxy in this area having a size between 20 and 200 percent of the Seyfert galaxy size.
35 years ago Baade and Minkowski (1954) suggested that a galaxy collision - diagnosed from the peculiar appearance of the parent object and its strong emission lines - is responsible for the strong radio-source CygA. This was the first time that gravitational interactions between galaxies were suggested to trigger nuclear activity. Over the following decades after the detection of the quasars and the gradual realization that quasars, comparable to the Seyfert phenomenon, are events at the nuclei of seemingly isolated galaxies, the collision hypothesis was abandoned. Efforts concentrated on the understanding of the activity as internal processes in the host galaxies, possibly aided by infall of gas from the intergalactic medium (cf. Rees, 1978; Gunn, 1979).
NGC 2992 is a nearby Seyfert galaxy (z=0.008, 1″=150 pc, for HO=75 km s−1 Mpc−1) seen almost edge-on (i=70°). A dust lane crossing the galaxy has been detected (Burbidge et al. 1972, see also Fig. 1) and the presence of two extended radio-emitting regions at position angles P.A. 130° and P.A. 160° has been reported (Ulvestad and Wilson, 1984).
This paper describes the programme for an in-situ radionuclide migration experiment in fractured crystalline rock and presents the first results of site characterisation work. This study is particularly notable for its extensive hydrologic/geochemical support programme and the use of radiotracers identified as important in safety assessment studies.
Multiple nucleus Markarian Galaxies may owe their origin to merging processes among galaxies. They may therefore be key objects for our understanding of galaxy evolution and the origin of nuclear activity. From morphological and multi-spectral data we show that these objects are in an unusually high state of dynamical and nuclear activity (starbursts, Seyfert activity) as would be expected from advanced stages of galaxy mergers.
Results from a spectroscopic survey of groups around Seyfert galaxies and of an appropriate control sample are reported. The groups are ≲1 Mpc across. A nuclear spectroscopic “activity class” is assigned to each group member. The active types show a peaked distribution around the Seyfert galaxy and are confined to a critical radius ~300 kpc while the nonactive members are uniformly distributed over the whole extent of the groups. These results are briefly discussed.