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  • 1
    Electronic Resource
    Electronic Resource
    SU(2) quantum kinematics: Rotation-observable versus angular-momentum generalized commutation relations (1998)
    College Park, Md. : American Institute of Physics (AIP)
    Journal of Mathematical Physics 39 (1998), S. 5798-5810 
    Details
    ISSN: 1089-7658
    Source: AIP Digital Archive
    Topics: Mathematics , Physics
    Notes: The canonical commutation relations of quantum mechanics are generalized to the case where appropriate dynamical variables are angular-momentum, rotation-angle, and rotation-axis observables. To this end, SU(2) is "quantized" on the compact group manifold, according to the standard procedure of non-Abelian quantum kinematics. Quantum-kinematic invariant operators are introduced, and their commutation relations with the rotation variables are found in an explicit manner. The quantum-kinematic invariants yield superselection rules in the form of eigenvalue equations of an isotopic structure (which one should solve in the applications, in order to get multiplets that carry the irreducible representations of the underlying quantum kinematic models). A wide range of applicability of SU(2) quantum kinematics is suggested. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.532594
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  • 2
    Electronic Resource
    Electronic Resource
    Is there always an influence of shoal size on predator hunting success? (1998)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 52 (1998), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Theoretical and empirical studies predict that there should be a decrease in hunting success of predators with increasing prey group size. Most of these studies investigated situations in which predator and prey were in full view of each other before, during and after an attack. In this study, single rock bass Ambloplites rupestris were given an opportunity to launch surprise attacks at shoals of creek chub Semotilus atromaculatus that ranged in size from two to 13 fish. There was no significant influence of either shoal size or attack distance on predator success rate and no significant relationship between attack distance and shoal size. Furthermore, it was found that the leading fish of a shoal was attacked significantly more often than fish in other shoal positions, indicating that predation risk was not shared equally among shoal members. Also, leading fish in larger shoals (eight to 13 fish) were not more likely to survive a predator attack than ones in small shoals (two to seven fish).The consequences of these results are discussed in the general context of antipredator benefits of grouping.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1998.tb02012.x
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  • 3
    Electronic Resource
    Electronic Resource
    Habitat choice in shoals of roach as a function of water temperature and feeding rate (1998)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 53 (1998), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Temperature and food availability are two important factors which affect fish growth and therefore are expected to influence habitat choice in fish. In this study, shoals of 16 juvenile roach, Rutilus rutilus, were given a choice between two chambers that differed in temperature by 1·5°C or 3°C whereas food availability was the same in both chambers (ratio 1 : 1) or higher in the colder one (ratio 4 : 1). The number of fish in each chamber was recorded for 10 min each during a pre-feeding, feeding and post-feeding period. Roach generally preferred the warmer over the colder chamber during the pre-feeding periods. Temperature had a significant effect on the distribution of fish during all three time periods whereas food availability was a significant factor only during the feeding period. The important role of temperature was emphasized further by the fact that a relatively small difference in the temperature gradient of 1·5°C had a stronger effect on fish distribution than a four times higher feeding rate during the feeding period. The implications for growth rates of such short-term decision-making of roach are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1998.tb00987.x
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  • 4
    Electronic Resource
    Electronic Resource
    Das hyperkinetische Syndrom (Aufmerksamkeitsdefizit-/ Hyperaktivitätsstörung) des Erwachsenenalters (1998)
    Springer
    Der Nervenarzt 69 (1998), S. 543-556 
    Details
    ISSN: 1433-0407
    Keywords: Schlüsselwörter Hyperkinetisches Syndrom beim Erwachsenen ; Aufmerksamkeitsdefizit-/Hyperaktivitätsstörung ; Methylphenidat ; Pemolin ; Key words Hyperkinetic syndrome ; Attention deficit ; Hyperactivity ; Impulsivity in adults
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The clinical picture of adult hyperkinetic syndrome (HKS) or attention deficit/hyperactivity disorder is nearly unknown in Germany. It can be estimated, that approximately one third of affected children also show symptoms as adults. In the combined type of the syndrome symptoms of inattention as well as of hyperactivity and impulsivity are present, a predominantly inattentive or hyperactive-impulsive type is possible. Retrospective diagnosis of HKS in childhood can be difficult. Disorganization, emotional disturbances and stress intolerance are common in adults with HKS as well as residual symptoms of learning disorders like dyslexia, dyscalculia and dysgraphia. In differential diagnosis especially affective, anxiety and antisocial personality disorders have to be considered, for which on the other side a frequent comorbidity with HKS is known. There is strong evidence for genetic transmission. Neurobiological findings revealed dysregulation of neurotransmitters. For treatment stimulants as pemoline and methamphetamin are effective, in addition tricyclic antidepressants or beta blockers; positive effects are probable for moclobemide, bupropion, fluoxetine and venlafaxine.
    Notes: Zusammenfassung Das Krankheitsbild des hyperkinetischen Syndroms (HKS) oder der Aufmerksamkeitsdefizit-/Hyperaktivitätsstörung beim Erwachsenen ist im deutschsprachigen Raum wenig bekannt. Es ist davon auszugehen, daß etwa ein Drittel der betroffenen Kinder Symptome auch im Erwachsenenalter zeigt. Beim Mischtypus finden sich sowohl Konzentrationsprobleme als auch motorische Unruhe und Impulsivität, deutliche Betonung der einen (vorwiegend unaufmerksamer Typus) oder anderen (vorwiegend hyperaktiv-impulsiver Typus) Symptomengruppe ist möglich. Die retrospektive Diagnose eines HKS im Kindesalter kann schwierig sein. Desorganisation im beruflichen und privaten Bereich, emotionale Störungen und Streßintoleranz sind bei Erwachsenen mit HKS häufig, Symptome von oft mit dem HKS vergesellschafteten Teilleistungsstörungen wie Lese- und Rechtschreibschwäche, Dysgraphie und Dyskalkulie können persistieren. Differentialdiagnostisch sind v. a. affektive Störungen, Angststörungen und dissoziale Entwicklungsstörungen abzugrenzen, wobei eine Komorbidität des HKS mit diesen Krankheitsbildern vorkommen kann. Ätiologisch ist eine genetische Ursache wahrscheinlich. Pathogenetisch ergeben sich Hinweise auf eine komplexe Dysregulation verschiedener Neurotransmitter. Therapeutisch können Pemolin und Methylphenidat, außerdem trizyklische Antidepressiva oder Betarezeptorenblocker eingesetzt werden; günstige Effekte sind wahrscheinlich für Moclobemid, Bupropion, Fluoxetin und Venlafaxin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001150050311
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  • 5
    Electronic Resource
    Electronic Resource
    ACE-Hemmer-induziertes Angioödem Die häufigste Ursache eines oropharyngealen Ödems (1998)
    Springer
    HNO 46 (1998), S. 56-59 
    Details
    ISSN: 1433-0458
    Keywords: Schlüsselwörter Angioödem ; ACE-Hemmer ; Medikamentennebenwirkungen ; Therapie ; Key words Angioedema ; Acetylcholinesterase inhibitor ; Drug side effects ; Therapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Acetylcholinesterase (ACE) inhibitor-induced angioedema is supposed to be an uncommon cause for oropharyngeal edema. Between January 1, 1993 and February 1, 1997 we treated 20 patients with edema of the oropharyngeal region that was not caused by infection or irradiation. The most common reason was an ACE-inhibitor-induced angioedema and occurred in 9 cases, all of whom required inpatient treatment. The medical management consisted of the administra- tion of intravenous (i.v.) glucocorticosteroids in all cases, H1-blockers in 6 cases, epinephrine by inhalation in one case and i.v. epinephrine in another case. Tracheostomy had to be performed in one patient. In our experience it is necessary to reconsider ACE inhibitor-induced angioedma in any case of an oropharyngeal edema. However, there is no reason for the routine application of epinephrine in these cases.
    Notes: Zusammenfassung Plötzlich auftretende Ödeme des Mund-Rachen-Bereichs sind potentiell lebensbedrohliche Erscheinungen. Ein durch ACE-Hemmer induziertes Angioödem gilt als seltene Differentialdiagnose. Zur Klärung der Frage, wie häufig ein ACE-Hemmer-induziertes Angioödem tatsächlich vorkommt, untersuchten wir in einer retrospektiven Studie das die Patienten, die in der Zeit von 1/93 bis 2/97 wegen eines akut aufgetretenen Ödems der oropharyngealen Region in der Universitäts-Hals-Nasen-Ohrenklinik Erlangen behandelt worden waren. Es handelte sich um 20 Patienten. Bei 9 Patienten lag ein ACE-Hemmer-induziertes Angioödem vor, das somit die häufigste Einzelgruppe darstellte. Alle Patienten wurden stationär aufgenommen. Allen Patienten wurden hochdosiert Glukokortikoide verabreicht, 6 Patienten zusätzlich ein H1-Blocker und je einem weitereren Patienten ein Adrenalin-Medihaler und Epinephrin i.v. Ein Patient mußte tracheotomiert werden. Nach unserer Erfahrung muß man somit bei jedem akuten Ödem im Mund-Rachen-Bereich an die Nebenwirkung von ACE-Hemmern denken. Die Gabe von Epinephrin ist nicht regelmäßig notwendig.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001060050197
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  • 6
    Electronic Resource
    Electronic Resource
    Quantum Kinematic Theory of the Poincare Group in Two-Dimensional Spacetime (1998)
    Springer
    International journal of theoretical physics 37 (1998), S. 759-784 
    Details
    ISSN: 1572-9575
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Non-Abelian quantum kinematics is applied to thePoincare group P + ↑ (1, 1),as an example of the quantization-through-the-symmetryapproach to quantum mechanics. Upon quantizing thegroup, generalized Heisenberg commutation relations are obtained, and aclosed Heisenberg–Weyl algebra follows. Then,according to the general theory, the three basicquantum-kinematic invariant operators are calculated;these afford the superselection rules for diagonalizing theincoherent rigged Hilbert space H(P + ↑ ) of the regularrepresentation. This paper examines only one of thesediagonalization schemes, while introducing a irreducible spacetime representation carried by isotopicplane-wave eigenvectors of two compatible superselectionoperators (which define a Poincare-invariant linear2-momentum). Thereafter, the principle of microcausality produces massive 2-spinor isotopic states in 1+ 1 Minkowski space. The Dirac equation is thus deducedwithin the quantum kinematic formalism, and the familiarJordan–Pauli propagation kernel in 2-dimensional spacetime is also obtained as a Hurwitzinvariant integral over the group manifold. The maininterest of this approach lies in the adoptedgroup-quantization technique, which is a strictlydeductive method and uses exclusively the assumed Poincaresymmetry.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026664412516
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