2,978 research outputs found
Implementing semantic tableaux
This report describes implementions of the tableau calculus for
first-order logic. First an extremely simple implementation,
called leanTAP, is presented, which nonetheless covers the full
functionality of the calculus and is also competitive with respect
to performance. A second approach uses compilation techniques for
proof search. Improvements inculding universal variables and
lemmata are considered as well as more efficient data structures
using reduced ordered binary decision diagrams. The implementation
language is PROLOG. In all cases fully operational PROLOG code is
given. For leanTAP a formal proof of the correctness of the
implementation is given relying on the operational semantics of
PROLOG as given by the SLD-tree model.
This report will appear as a chapter in the
Handbook of Tableau-based Methods in Automated Deduction
edited by: D. Gabbay, M. D\u27Agostino, R. H\"{a}hnle, and
J.Posegga
published by: KLUWER ACADEMIC PUBLISHERS
Electronic availability will be discontinued after final acceptance
for publication is obtained
Bestimmung der glomerulÀren Filtrationsrate bei Kindern und Jugendlichen: Alternative Methoden zur Inulin-Clearance und der Einfluss der laborchemischen Untersuchungsmethoden
Hintergrund:
Welche Methode zur Bestimmung der glomerulĂ€ren Filtrationsrate (GFR) bei Kindern im klinischen Alltag die beste Ăbereinstimmung mit der Inulin-Clearance liefert, ist in der Literatur nicht eindeutig geklĂ€rt.
Patienten und Methoden:
An 27 Patienten wurden parallel zur Inulin-Clearance 10 verschiedene GFR-Bestimmungsmethoden evaluiert. Eine Kurz-Zeit-Kreatinin-Clearance mit 3 x 90 minĂŒtiger Urinsammlung, eine klassische 24-Stunden-Kreatinin-Clearance, eine Formelberechnung nach Schwartz sowie die Bestimmung von Cystatin C. Die Kreatinin-Bestimmungen erfolgten aus jeder Probe durch drei verschieden Tests: naĂ-enzymatisch durch Creatinin plus, trocken-enzymatisch durch Ektachem und durch die klassische JaffĂ©-Methode.
AuĂerdem wurde an sechs erwachsenen Kontrollprobanden das gesamte Studienprotokoll an zwei aufeinander folgenden Tagen durchgefĂŒhrt.
Ergebnisse:
Alle 10 Methoden wichen in klinisch relevantem MaĂ von der Inulin-Clearance ab.
Die Kurz-Zeit-Kreatinin-Clearance lieferte Àhnliche Werte, wie die 24-Stunden-Kreatinin-Clearance.
Die Bestimmung der GFR durch die Schwartz-Clearance, bestimmt mit dem klassischen JaffĂ©-Test, lieferte die beste Ăbereinstimmung mit der Inulin-Clearance und ist zudem am wenigsten belastend fĂŒr Kinder.
Auch bei den erwachsenen Kontrollprobanden zeigte sich durch diese Methode die geringste von Tag-zu-Tag-Abweichung.
Die Kreatinin-abhĂ€ngigen Methoden zeigen unabhĂ€ngig von der Untersuchungsmethode mit JaffĂ© die beste Ăbereinstimmung mit der Inulin-Clearance.
Schlussfolgerung:
Keine der 10 untersuchten Methoden kann die GFR zuverlÀssig bestimmen.
Die Schwartz-Clearance bestimmt durch JaffĂ© ist fĂŒr den klinischen Alltag die Methode der besten Ăbereinstimmung mit der tatsĂ€chlichen GFR und ist zudem einfach durch zu fĂŒhren und fĂŒr den Patienten wenig belastend
Weekly assessment of worry: an adaptation of the Penn State Worry Questionnaire for monitoring changes during treatment
An adaptation of the Penn State Worry Questionnaire (PSWQ) [Meyer, T. J., Miller, M. L., Metzger, R. L. and Borkovec, T. D. (1990). Development and validation of the Penn State Worry Questionnaire. Behaviour Research and Therapy, 28, 487-495.] for weekly assessment of worry was evaluated in a brief treatment study. Cognitive restructuring techniques were taught to 28 nonclinical high-worriers, 14 of whom served as a control group in a lagged waiting-list design. Results showed that the Penn State Worry Questionnaire-Past Week (PSWQ-PW) was highly reliable and substantially valid in the assessment of both (a) weekly status of worry and (b) treatment-related changes in worry: average Cronbach's alpha was 0.91; average convergent correlation with a past-week adaptation of the Worry Domains Questionnaire [Tallis, F., Eysenck, M. W. and Mathews, A. (1992). A questionnaire for the measurement of nonpathological worry. Personality and Individual Differences, 13, 161-168.] was 0.63 and pre-post improvement on PSWQ-PW showed a 0.71 correlation with the Questionnaire of Changes in Experiencing and Behavior [Zielke, M. and Kopf-Mehnert, C. (1978). VerÀnderungsfragebogen des Erlebens und Verhaltens. Weinheim, Germany: Beltz Test Gesellschaft.]. It is concluded that the PSWQ-PW is a useful instrument for monitoring pathological worry in experimental and applied settings
The role of the Kupferschiefer in the formation of hydrothermal base metal mineralization in the Spessart ore district, Germany: insight from detailed sulfur isotope studies
The Spessart district (SW Germany), located at the southwestern margin of the Permian Kupferschiefer basin in Central Europe, hosts abundant stratabound and structurally controlled base metal mineralization. The mineralization styles identified are (1) stratabound Cu-Pb-Zn-(Ag) ores in Zechstein sedimentary rocks, (2) structurally controlled Cu-As-(Ag) ores in Zechstein sedimentary rocks, (3) crosscutting Co-Ni-(Bi)-As and Cu-Fe-As veins, (4) stratabound metasomatic Fe-Mn carbonate ores in Zechstein dolomite, (5) barren barite veins, and (6) Fe-Mn-As veins in Permian rhyolites. Building on previous work that involved mineralogical, textural, and chemical characterization of the major mineralization types, we have performed a comprehensive sulfur isotope study that applied both conventional and novel laser-ablation multi-collector inductively coupled plasma mass spectrometry techniques. The ÎŽ34S values of sulfide minerals from the different ore types are consistently negative and highly variable, in the range between â44.5â° and â3.9â°, whereas the ÎŽ34S values of barite are all positive in the range between 4.7â° and 18.9â°. Remarkably, stratabound and structurally controlled mineralization in Zechstein sedimentary rocks has the least negative ÎŽ34S values, whereas vein-type deposits have consistently more negative ÎŽ34S values. The observed pattern of sulfide ÎŽ34S values can be best interpreted in terms of fluid mixing at the basement-cover interface. Hydrothermal fluids originating from the crystalline basement migrated upward along subvertical fault zones and were periodically injected into groundwaters that were flowing in the post-Variscan sedimentary cover. These groundwaters had interacted with the Zechstein sedimentary rocks, resulting in fluids characterized by elevated concentrations of reduced sulfur (with negative ÎŽ34S values) and alkaline pH. Repeated mixing between both chemically contrasting fluids caused rapid and efficient precipitation of sulfide ore minerals in hydrothermal veins with highly variable but distinctly negative ÎŽ34S value
Bile acid retention and activation of endogenous hepatic farnesoid-X-receptor in the pathogenesis of fatty liver disease in ob/ob-mice
The nuclear bile acid receptor FXR (farnesoid-X-receptor) has recently been implicated in the pathophysiology of non-alcoholic fatty liver disease because selective FXR-agonists improve glucose and lipid metabolism in rodent models of obesity. However, the regulation of FXR and other relevant nuclear receptors as well as their lipogenic target genes in fatty liver is still not revealed in detail. Livers were harvested from 14-week-old male ob/ob mice and wild-type controls. Serum bile acids were quantified by radioimmunoassay. mRNA and protein expression of transporters and nuclear receptors was analyzed by reverse transcriptase-polymerase chain reaction and Western blotting, whereas DNA binding to the IR-1 element was examined by electrophoretic mobility shift assay. In this study we show: (i) bile acid retention in ob/ob mice, (ii) a resulting FXR upregulation and binding to the IR-1 element in ob/ob animals and (iii) concomitant activation of the fatty acid synthase as a potential lipogenic FXR target gene in vivo. The present study suggests a potential role of hepatic bile acid retention and FXR activation in the induction of lipogenic target genes. Differences between intestinal and hepatic FXR could explain apparent contradictory information regarding its effects on fatty liver diseas
Correlated Three-Electron Continuum States in Triple Ionization by Fast Heavy-Ion Impact
We have performed a kinematically complete experiment for triple ionization in atomic collisions. Data were obtained for 3.6-MeV/amu Au53+ impact on Ne. A specific Dalitz representation was developed allowing one to plot in a single spectrum the energy of all three ionized electrons and, simultaneously, obtain information on their emission angles with respect to the projectile direction. The data show distinct fragmentation patterns favoring very asymmetric energy partitionings with one fast and two slow electrons. They are compared to various Classical Trajectory Monte Carlo (CTMC) models. The experimental results are well described only if the electron-electron interaction is included throughout the collision and surprisingly, if the classically modeled electrons are fully correlated in the initial state
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