1,998 research outputs found

    The Zero-Removing Property and Lagrange-Type Interpolation Series

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    The classical Kramer sampling theorem, which provides a method for obtaining orthogonal sampling formulas, can be formulated in a more general nonorthogonal setting. In this setting, a challenging problem is to characterize the situations when the obtained nonorthogonal sampling formulas can be expressed as Lagrange-type interpolation series. In this article a necessary and sufficient condition is given in terms of the zero removing property. Roughly speaking, this property concerns the stability of the sampled functions on removing a finite number of their zeros

    Percolation on two- and three-dimensional lattices

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    In this work we apply a highly efficient Monte Carlo algorithm recently proposed by Newman and Ziff to treat percolation problems. The site and bond percolation are studied on a number of lattices in two and three dimensions. Quite good results for the wrapping probabilities, correlation length critical exponent and critical concentration are obtained for the square, simple cubic, HCP and hexagonal lattices by using relatively small systems. We also confirm the universal aspect of the wrapping probabilities regarding site and bond dilution.Comment: 15 pages, 6 figures, 3 table

    Some extremal functions in Fourier analysis, III

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    We obtain the best approximation in L1(R)L^1(\R), by entire functions of exponential type, for a class of even functions that includes eλxe^{-\lambda|x|}, where λ>0\lambda >0, logx\log |x| and xα|x|^{\alpha}, where 1<α<1-1 < \alpha < 1. We also give periodic versions of these results where the approximating functions are trigonometric polynomials of bounded degree.Comment: 26 pages. Submitte

    The IRIS Network of Excellence:: Integrating Research in Interactive Storytelling

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    Abstract. Interactive Storytelling is a major endeavour to develop new media which could offer a radically new user experience, with a potential to revolutionise digital entertainment. European research in Interactive Storytelling has played a leading role in the development of the field, and this creates a unique opportunity to strengthen its position even further by structuring collaboration between some of its main actors. IRIS (Integrating Research in Interactive Storytelling) aims at creating a virtual centre of excellence that will be able to progress the understanding of fundamental aspects of Interactive Storytelling and the development of corresponding technologies

    Extragalactic jets on subpc and large scales

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    Jets can be probed in their innermost regions (d~0.1 pc) through the study of the relativistically-boosted emission of blazars. On the other extreme of spatial scales, the study of structure and dynamics of extragalactic relativistic jets received renewed impulse after the discovery, made by Chandra, of bright X-ray emission from regions at distances larger than hundreds of kpc from the central engine. At both scales it is thus possible to infer some of the basic parameters of the flow (speed, density, magnetic field intensity, power). After a brief review of the available observational evidence, I discuss how the comparison between the physical quantities independently derived at the two scales can be used to shed light on the global dynamics of the jet, from the innermost regions to the hundreds of kpc scale.Comment: Proceedings of the 5th Stromlo Symposium: Disks, Winds, and Jets - from Planets to Quasars. Accepted, to be published in Astrophysics & Space Scienc

    Multipliers for p-Bessel sequences in Banach spaces

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    Multipliers have been recently introduced as operators for Bessel sequences and frames in Hilbert spaces. These operators are defined by a fixed multiplication pattern (the symbol) which is inserted between the analysis and synthesis operators. In this paper, we will generalize the concept of Bessel multipliers for p-Bessel and p-Riesz sequences in Banach spaces. It will be shown that bounded symbols lead to bounded operators. Symbols converging to zero induce compact operators. Furthermore, we will give sufficient conditions for multipliers to be nuclear operators. Finally, we will show the continuous dependency of the multipliers on their parameters.Comment: 17 page

    Herpes nodules in the lung of the African elephant, Loxodonta africana (Blumenbach, 1797)

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    Lymphoid nodules associated with Cowdry Type A intranuclear inclusions in epithelial and syncytial cells were found in the lungs of 74% of 50 African elephants in the Kruger National Park. Subsequent studies proved these were caused by a herpes virus (Erasmus, McCully, Pienaar, Young, Pieterse & Els, 1971). The disease appears to be subclinical or latent. This virus, in common with other herpes viruses, might be more pathogenic in some other host. The pathogenesis of the lymphoid nodules and the various stages of their formation are given and the detailed characteristics are illustrated.The journals have been scanned in colour with a HP 5590 scanner; 600 dpi. Adobe Acrobat v.11 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

    The democratic origins of the term "group analysis": Karl Mannheim's "third way" for psychoanalysis and social science.

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    It is well known that Foulkes acknowledged Karl Mannheim as the first to use the term ‘group analysis’. However, Mannheim’s work is otherwise not well known. This article examines the foundations of Mannheim’s sociological interest in groups using the Frankfurt School (1929–1933) as a start point through to the brief correspondence of 1945 between Mannheim and Foulkes (previously unpublished). It is argued that there is close conjunction between Mannheim’s and Foulkes’s revision of clinical psychoanalysis along sociological lines. Current renderings of the Frankfurt School tradition pay almost exclusive attention to the American connection (Herbert Marcuse, Eric Fromm, Theodor Adorno and Max Horkheimer) overlooking the contribution of the English connection through the work of Mannheim and Foulkes

    Dynamic Scaling in Diluted Systems Phase Transitions: Deactivation trough Thermal Dilution

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    Activated scaling is confirmed to hold in transverse field induced phase transitions of randomly diluted Ising systems. Quantum Monte Carlo calculations have been made not just at the percolation threshold but well bellow and above it including the Griffiths-McCoy phase. A novel deactivation phenomena in the Griffiths-McCoy phase is observed using a thermal (in contrast to random) dilution of the system.Comment: 4 pages, 4 figures, RevTe

    Some parasitic and other natural diseases of the African elephant in the Kruger National Park

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    Detailed descriptions are given of the lesions encountered at autopsy on a random selection of 32 free-living African elephants [Loxodonta africana (Blumenbach, 1797)]. Lymphoid nodules with inclusion bearing syncytia caused by a herpes virus were found in many lungs and similar lesions occurred in the pancreas. Suspected viral lesions somewhat resembling bovine granular vaginitis were encountered in the genitalia. Dipetalonema gossi Baylis, 1923, which was originally recorded from the abdominal cavity, was recovered from the portal veins of several animals. They proved to be responsible for severe intrahepatic vasculitis and eosinophilic hepatitis in 50% of the elephants. Grammocephalus clathratus (Baird, 1868) Railliet & Henry 1910 was constantly present in the bile ducts where fairly marked cholangitis was produced. Even mild localized pancreatitis was sometimes caused by these parasites. Parabronema africanum Baylis, 1921 was found in large numbers in gastric ulcers. A new mite, Loxanoetus bassoni Fain, 1970 was obtained from the ears. The livers of two elephants contained a few suspected schistosome ova. Siderotic and haemangiomatoid splenic lesions occurred in several adult animals. Many of the cows had multiple periuterine papillomata. Arteriosclerosis of the aorta was occasionally encountered. Skin lesions resembling porcine lesions of zinc deficiency were observed. Mycotic lesions were seen once in the lungs and lymph nodes. The aetiology of focal disseminated cystitis in 39% of the cows was not established.The journals have been scanned in colour with a HP 5590 scanner; 600 dpi. Adobe Acrobat v.11 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format
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