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  • 1
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Chaos 4 (1994), S. 203-212 
    ISSN: 1089-7682
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Large, long-lived vortices, surviving during many turnaround times and far longer than the dispersive linear Rossby wave packets, are abundant in planetary atmospheres and oceans. Nonlinear effects which prevent dispersive decay of intense cyclones and anticyclones and provide their self-propelling propagation are revised here using shallow water equations and their balanced approximations. The main physical mechanism allowing vortical structures to be long-lived in planetary fluid is the quick fluid rotation inside their cores which prevents growth in the amplitude of asymmetric circulation arising due to the beta-effect. Intense vortices of both signs survive essentially longer than the linear Rossby wave packet if their azimuthal velocity is much larger than the Rossby wave speed. However, in the long-time evolution, cyclonic and anticyclonic vortices behave essentially differently that is illustrated by the conservative intermediate geostrophic model. Asymmetric circulation governing vortex propagation is described by the azimuthal mode m=1 for the initial value problem as well as for steadily propagating solutions. Cyclonic vortices move west-poleward decaying gradually due to Rossby wave radiation while anticyclonic ones adjust to non-radiating solitary vortices. Slow weakening of an intense cyclone with decreasing of its size and shrinking of the core is described assuming zero azimuthal velocity outside the core while drifting poleward. The poleward tendency of the cyclone motion relative to the stirring flow corresponds to characteristic trajectories of tropical cyclones in the Earth's atmosphere. The asymmetry in dispersion-nonlinear properties of cyclones and anticyclones is thought to be one of the essential reasons for the observed predominance of anticyclones among long-lived vortices in the atmospheres of the giant planets and also among intrathermoclinic eddies in the ocean.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Industrial & engineering chemistry research 33 (1994), S. 2248-2250 
    ISSN: 1520-5045
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Chromatography B: Biomedical Sciences and Applications 613 (1993), S. 34-42 
    ISSN: 0378-4347
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1433-0474
    Keywords: Schlüsselwörter Herzerkrankung ; Thoraxschmerz ; Psychosomatische Störung ; Key words Heart disease ; Chest pain ; Psychosomatic disorder
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Aims: Chest pain in children is often suspected to originate from cardiac disease. Aim of this study was to characterise the symptomatology of supposed cardiac chest pain in children and to investigate whether cardiac disease indeed underlies the pain or not. Furthermore, indications for a psychosomatic origin of the pain were searched for. Methods: The study involved 456 children referred to a pediatric cardiology outpatient department for chest pain. The patients were evaluated by ECG and echocardiogram. In selected cases, a chest radiograph, exercise ECG, or a 24-hour ECG monitoring was performed. A subgroup of 52 children and parents was interviewed on the basis of a questionnaire to evaluate the symptomatology of the pain, the family history, and psychosocial factors. Results: 15% of the children had diverse structural anomalies or arrhythmias usually of a low grade. The frequency of these findings did not differ from that of a control group without chest pain. Independent of the presence of these findings cardiac function was normal during exercise. The characteristic symptomatology (short, sharp, no radiation) did not correspond to that of ischemic heart disease, and was largely identical in children with and without cardiac findings. Factors typical of psychosomatic disorders were observed: a positive family history of „functional cardiac complaints” and other psychosomatic disorders particularly with regard to the mother, other somatic complaints prior to or along with the chest pain, and the presence of stressful life events. Conclusions: These data suggest that the described chest pain in children is a psychosomatic condition rather than caused by organic cardiac disease.
    Notes: Zusammenfassung Fragestellung: Thoraxschmerzen bei Kindern werden häufig mit Erkrankungen des Herzens in Zusammenhang gebracht. Im Rahmen dieser Studie sollten der Symptomkomplex kindlicher „Herzschmerzen” charakterisiert und seine Genese aus kardiologischer Sicht untersucht werden. Ein weiteres Ziel bestand darin, Hinweise auf psychogene Faktoren in der Schmerzgenese zu erhalten. Methode: In die Studie waren 456 Kinder einbezogen, die unter dem Verdacht von „Herzschmerzen” an kinderkardiologische Ambulanzen überwiesen worden waren. Die Basisdiagnostik umfaßte EKG und Echokardiographie. In vielen Fällen erfolgten zusätzlich Langzeit-EKG, Thoraxröntgen oder Belastungs-EKG. Zur Beschreibung der Symptomatik und zur Evaluierung familiärer und psychosozialer Faktoren wurde ein Fragebogen ausgearbeitet und damit eine Untergruppe von 52 Kindern untersucht. Ergebnisse: Bei 15% der Kinder wurden verschiedenartige und meist geringfügige strukturelle und funktionelle Abweichungen vom Normalbefund des Herzens beobachtet. Ihre Prävalenz war nicht höher als in einer Kontrollpopulation. Unabhängig vom Vorhandensein dieser Befunde war die kardiale Leistungsfähigkeit normal. Die typische Symptomatik (kurz, stechend, ohne Ausstrahlung) entsprach nicht der des ischämischen Herzschmerzes und war bei Kindern mit und ohne kardiale Veränderungen weitgehend identisch. Es wurden Faktoren beobachtet, die typisch für psychosomatische Erkrankungen sind: eine positive Familienanamnese für „funktionelle Herzbeschwerden” und andere psychosomatische Erkrankungen insbesondere hinsichtlich der Mutter, das gleichzeitige oder zeitlich versetzte Auftreten anderer Schmerzsyndrome und potentielle psychosoziale Belastungen. Schlußfolgerungen: Vermutlich spielen nicht manifeste organische Veränderungen am Herzen, sondern psychosomatische Faktoren in der Pathogenese des hier charakterisierten kindlichen Thoraxschmerzes eine Rolle.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-0956
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Large, long-lived vortices are abundant in the atmospheres of the giant planets. Some of them survive a few orders of magnitude longer than the dispersive linear Rossby wave packets, e.g. the Great Red Spot (GRS), Little Red Spot (LRS) and White Ovals (WO) of Jupiter, Big Bertha, Brown Spot and Anne's Spot of Saturn, the Great Dark Spot (GDS) of Neptune, etc. Nonlinear effects which prevent their dispersion spreading are the main subject of our consideration. Particular emphasis is placed on determining the dynamical processes which may explain the remarkable properties of observed vortices such as anticyclonic rotation in preference to cyclonic one and the uniqueness of the GRS, the largest coherent vortex, along the perimeter of Jupiter at corresponding latitude. We review recent experimental and theoretical studies of steadily translating solitary Rossby vortices (anticyclones) in a rotating shallow fluid. Two-dimensional monopolar solitary vortices trap fluid which is transported westward. These dualistic structures appear to be vortices, on the one hand, and solitary “waves”, on the other hand. Owing to the presence of the trapped fluid, such solitary structures collide inelastically and have a memory of the initial disturbance which is responsible for the formation of the structure. As a consequence, they have no definite relationship between the amplitude and characteristic size. Their vortical properties are connected with geostrophic advection of local vorticity. Their solitary properties (nonspreading and stationary translation) are due to a balance between Rossby wave dispersion and nonlinear effects which allow the anticyclones, with an elevation of a free surface, to propagate faster than the linear waves, without a resonance with linear waves, i.e. without wave radiation. On the other hand, cyclones, with a depression of a free surface, are dispersive and nonstationary features. This asymmetry in dispersion-nonlinear properties of cyclones and anticyclones is thought to be one of the essential reasons for the observed predominance of anticyclones among the long-lived vortices in the atmospheres of the giant planets and also among the intrathermocline oceanic eddies. The effects of shear flows and differences between the properties of monopolar vortices in planetary flows and various laboratory experiments are discussed. General geostrophic (GG) theory of Rossby vortices is presented. It differs essentially from the traditional quasi-geostrophic (QG) and intermediate-geostrophic (IG) approximations by the account of (i) all scales between the deformation radius and the planetary scale and (ii) the arbitrary amplitudes of vortices. It is shown that, unlike QG- and IG-models, the GG-model allows for explaining the mentioned cyclonic-anticyclonic asymmetry not only in planetary flows, but also in laboratory modeling with vessels of near paraboloidal form.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of cancer research and clinical oncology 63 (1960), S. 511-518 
    ISSN: 1432-1335
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The changes in the content of nucleic acids and in the adsorption capacity of RNS in skin tumors of mice induced by benzpyrene have been studied. The cytochemical observations revealed an increased RNA basophilia of the cytoplasm and nucleoli. The DNA basophilia of the nuclei remained either normal or in some cells was increased. The importance of selecting the proper tissue for controls in the biochemical investigations was pointed out. The RNA and the DNA in the tumors were greatly increased when compared with the skin. When compared with the content of RNA of epidermis, which from the histogenetic point of view is a much more adequate control, the RNA in the papilloma decreased, reaching the value for the epidermis only in fully developed carcinoma. The content of DNA of all tumors was decreased, however, due to the presence of some connective tissue and of cornified regions in the tumors. The ratio RNA/DNA of the tumors was always increased, independent of the tissue taken as control, thus indicating an increased content of RNA per cell. It was shown that the RNA of the tumor tissue bound more pyronine than that of normal skin. The authors assumed, on the basis of their previous investigations and from data given in the literature, that the increased adsorption capacity of RNA in the tumor tissue was due to the presence of a greater quantity of free RNA: that is, RNA not linked to the protein and hence more active metabolically.
    Notes: Zusammenfassung Es werden die Veränderungen im Nucleinsäuregehalt wie auch die Adsorptionsfähigkeit der RNS in durch Benzpyren induzierten Hauttumoren bei Mäusen untersucht. Histochemisch wurde eine gesteigerte RNS-Basophilie im Cytoplasma und in den Nucleolen und normale oder in manchen Kernen gesteigerte DNS-Basophilie festgestellt. Bei den biochemischen Befunden ist die Bedeutung des zum Vergleich herangezogenen Kontrollgewebes betont. Den Hautkontrollen gegenübergestellt, ist der Gehalt beider Nucleinsäuren in den Geschwulsten wesentlich erhöht, während im Vergleich zur Epidermis, die histogenetisch den Hauttumoren viel näher steht, der RNS-Gehalt in den Papillomen herabgesetzt ist und erst in den völlig entwickelten Carcinomen die RNS-Werte der Epidermis erreicht. Der DNS-Gehalt dagegen ist in beiden Geschwülstgruppen niedriger, was auf das Vorhandensein verhornender Bezirke wie auch auf das bindegewebige Stroma zurückzuführen ist. Abgesehen von dem zum Vergleich herangezogenen Kontrollgewebe ist das Verhältnis RNS/DNS in den Tumoren immer erhöht, was auf einen angestiegenen RNS-Gehalt pro Zelle hinweist. Es wurde weiter gezeigt, daß die RNS im Tumorgewebe das Pyronin mehr als in den betreffenden Hautkontrollen an sich bindet. Auf Grund ihrer früheren Untersuchungen als auch gewisser Literaturangaben nehmen die Verfasser an, daß die gesteigerte Adsorptionsfähigkeit der RNS im Tumorgewebe durch das Vorhandensein von mehr freier, d. h. nicht eiweißgebundener und infolgedessen metabolisch wirksamerer RNS bedingt ist.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 20 (1997), S. 378-383 
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Catalytic decontamination of waste gases in a fixed bed reactor, operating at non-steady state conditions achieved by periodic gas flow reversal, is simulated on the basis of a mathematical model. The opportunity to utilize a significant part of the reaction heat is discussed and the effect of catalyst inactivation upon reactor performance is analyzed. Stable temperature regime and conversion exceeding 99.5% could be ensured by a more than eightfold reduction of catalyst activity.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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