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  • 36.10.Dr  (6)
  • 25.30.−c  (4)
  • Computational geometry  (4)
  • phase II  (4)
  • 1
    ISSN: 1434-601X
    Schlagwort(e): 13.10. + q ; 23.20.-g ; 36.10.-k ; 36.10.Dr
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The probabilities for non-radiative (n.r.) excitationsP n.r. in the muonic nuclides208Pb,232Th, and238U have been determined from (μ−,γγ)-measurements by comparing the intensities of muonic X-ray transitions in single and coincidence spectra. The value ofP n.r. (3p→1s), measured for the first time, is about 90% for the actinides232Th and238U, but only about 8% for208Pb. The value ofP n.r. (3d→1s) is found to be 10 % for233Th, 13% for238U, and about 4% for208Pb. For208Pb a vanishing strength of the n.r. decay of the 2p-level is found, while for232Th and for238U n.r. strengths of about 20% and 26%, respectively, are observed. By regarding two subcomplexes of the 2p→1s transitions leading to different mean excitation energies the n.r. transition probabilities were found to be different for238U only, 21.6% and 31.1.%, respectively.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Algorithmica 3 (1988), S. 473-485 
    ISSN: 1432-0541
    Schlagwort(e): Computational geometry ; Curves ; Simplicity testing ; Intersection detection ; Monotone decomposition ; Convex decomposition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik , Mathematik
    Notizen: Abstract A splinegon is a polygon whose edges have been replaced by “well-behaved” curves. We show how to decompose a simple splinegon into a union of monotone pieces and into a union of differences of unions of convex pieces. We also show how to use a fast triangulation algorithm to test whether two given simple splinegons intersect. We conclude with examples of splinegons that make the extension of algorithms from polygons to splinegons difficult.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Algorithmica 4 (1989), S. 3-32 
    ISSN: 1432-0541
    Schlagwort(e): Three-dimensional cell complexes ; Data structures ; Computational geometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik , Mathematik
    Notizen: Abstract Algorithms for manipulating three-dimensional cell complexes are seldom implemented due to the lack of a suitable data structure for representing them. Such a data structure is proposed here along with the primitive operations necessary to make it useful. Applications of the structure are also given.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Algorithmica 5 (1990), S. 421-457 
    ISSN: 1432-0541
    Schlagwort(e): Computational geometry ; Splinegon ; Curve algorithm ; Convexity ; Monotonicity ; Intersection ; Kernel ; diameter decomposition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik , Mathematik
    Notizen: Abstract We extend the results of straight-edged computational geometry into the curved world by defining a pair of new geometric objects, thesplinegon and thesplinehedron, as curved generalizations of the polygon and polyhedron. We identify three distinct techniques for extending polygon algorithms to splinegons: the carrier polygon approach, the bounding polygon approach, and the direct approach. By these methods, large groups of algorithms for polygons can be extended as a class to encompass these new objects. In general, if the original polygon algorithm has time complexityO(f(n)), the comparable splinegon algorithm has time complexity at worstO(Kf(n)) whereK represents a constant number of calls to members of a set of primitive procedures on individual curved edges. These techniques also apply to splinehedra. In addition to presenting the general methods, we state and prove a series of specific theorems. Problem areas include convex hull computation, diameter computation, intersection detection and computation, kernel computation, monotonicity testing, and monotone decomposition, among others.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Algorithmica 5 (1990), S. 561-571 
    ISSN: 1432-0541
    Schlagwort(e): Computational geometry ; Empty convex subsets ; Analysis of algorithms ; Combinatorial geometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik , Mathematik
    Notizen: Abstract A key problem in computational geometry is the identification of subsets of a point set having particular properties. We study this problem for the properties of convexity and emptiness. We show that finding empty triangles is related to the problem of determining pairs of vertices that see each other in a star-shaped polygon. A linear-time algorithm for this problem which is of independent interest yields an optimal algorithm for finding all empty triangles. This result is then extended to an algorithm for finding empty convex r-gons (r〉 3) and for determining a largest empty convex subset. Finally, extensions to higher dimensions are mentioned.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Investigational new drugs 10 (1992), S. 205-209 
    ISSN: 1573-0646
    Schlagwort(e): phase II ; fazarabine ; adenocarcinoma ; pancreas
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Abstract We conducted a phase II evaluation of fazarabine 1.75–2.0 mg/m2hr over 72 hours every 28 days in 14 previously untreated patients with advanced adenocarcinoma of the pancreas. The intial dose was 1.75 mg/m2/hr in 10 patients, and 2.0 mg/m2hr in 4 patients. The dose was escalated in 8 patients, including all 4 who started at the higher dose level. Toxicity was unexpectedly mild. The median WBC nadir was 4.4 (range: 2.4–15.8)×103/μl, the median absolute neutrophil nadir was 3.2 (range: 0.9–13.0)×103/μl, and the median platelet count was 134.0 (range: 48.0–291.0)×103/μl. Gastrointestinal toxicity was generally mild. No major responses were seen, excluding, with 95% confidence, a response rate in excess of 20%.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Investigational new drugs 10 (1992), S. 313-316 
    ISSN: 1573-0646
    Schlagwort(e): phase II ; edatrexate ; adenocarcinoma ; pancreas
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Abstract We conducted a phase II evaluation of edatrexate in 17 previously untreated patients with advanced adenocarcinoma of the pancreas; 14 patients had at least one month of therapy. The initial dose was 80 mg/m2iv. Treatment was administered weekly for 5 weeks, then every other week. Toxicity was generally mild. The median WBC nadir was 5.4 (range 0.6–7.4)×103/μl, and the median platelet nadir was 164.0 (range 62.0–341.0)×103/μl. One patient died with sepsis and gastrointestinal bleeding associated with pancytopenia. Five patients had a mild rash. Nausea occurred in 6 patients, including 3 who had vomiting. In addition, 11 patients complained of vague malaise which seemed to begin within 24–48 hours after administration of edatrexate, and lasted for 2 to 3 days, resolving within 6 days of drug administration. Median survival was 85 days. Although 5 patients had stable disease, including one with relief of pain, no major responses were seen, excluding, with 95% confidence, a response rate in excess of 20%.
    Materialart: Digitale Medien
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  • 8
    ISSN: 1434-601X
    Schlagwort(e): 13.10.+q ; 23.20.−g ; 36.10.−k ; 36.10.Dr
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The probability for non-radiative (n.r.) excitations in muonic209Bi was determined from a (μ −,γγ)-measurement by comparing the intensities of muonic X-ray transitions in single and coincidence spectra. The values of Pn.r(3p→1s)=(17.9±2.0)% and Pn.r.(3d→1s)=(3.0±2.2)% were measured for the first time. The strength of the n.r. decay of the 2p-level was found to be (4.2±2.2)%. The n.r. transition probabilities of two subcomplexes of the (2p→1s)-transition leading to different mean excitation energies are (3.2±1.8)% and (5.0±2.0)%, respectively.
    Materialart: Digitale Medien
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  • 9
    ISSN: 1434-601X
    Schlagwort(e): 23.40.−s ; 25.30.−c ; 25.85.−w
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Fission fragments from the reaction237Np(μ −,γ,f) have been measured in coincidence with muonic X-rays. The efficiency of the fission fragment detector is determined from (μ −,γ,f)-data of the same experiment. The total fission probability perμ-stopP t has been measured as well as the fission probabilities Pf of the non-radiative muonic (3d→1s)- and (2p→1s)-transitions; the latter has been divided into two parts leading to different mean excitation energiesE:P t =(54±17)%,P f (3d→1s)=(41±21)%,P f (2p→1s,E=6.218 MeV)=(61±19)%, andP f (2p→1s,E=6.525 MeV)=(57±18)%. The influence of the muon on the fission barrier is discussed. The fission probability after muon capture is compared with a calculated value using a distribution of nuclear excitation energies following muon capture and the fission probability as measured in a238U(3He,αf)-reaction.
    Materialart: Digitale Medien
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  • 10
    ISSN: 1434-601X
    Schlagwort(e): 13.10.+q ; 14.60.Ef ; 25.85.Ge ; 27.90.+b ; 36.10.Dr
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The ratios of prompt to delayed fission yields for the isotopes233U,234U,235U,236U,238U,237Np,242Pu, and244Pu and the fission probabilities relative to each other have been investigated experimentally. Using the value of the total fission probability for237Np the absolute probabilities for prompt and delayed fission have been determined. The fission probabilities per muon captureP fc have been derived for all the isotopes and compared with an evaluation based on excitation functions from theory.
    Materialart: Digitale Medien
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