Obtaining Maxwell's equations heuristically

Starting from the experimental fact that a moving charge experiences the Lorentz force and applying the fundamental principles of simplicity (first order derivatives only) and linearity (superposition principle), we show that the structure of the microscopic Maxwell equations for the electromagnetic fields can be deduced heuristically by using the transformation properties of the fields under space inversion and time reversal. Using the experimental facts of charge conservation and that electromagnetic waves propagate with the speed of light together with Galileo invariance of the Lorentz force allows us to introduce arbitrary electrodynamic units naturally.Comment: 11 page

The siliciclastic sediments of the synorogenic Hochwipfel Formation in the Carboniferous of the Western Karawanken Mountains (Austria/Slovenia/Italy) : sedimentology, geochemistry and provenance

Die vorliegende Arbeit befaßt sich mit den karbonen Sedimenten der Westkarawanken (Österreich/Slowenien/Italien). Mit Hilfe eines kombinierten sedimentologisch-petrographisch-geochemischen Untersuchungsansatzes wird ein Modell für die Provenienz, die karbone Entwicklung des Ablagerungsraumes sowie dessen geodynamische Stellung während des jüngeren Paläozoikum vorgeschlagen. Zur Anwendung kamen folgende Methoden: Dünnschliffpetrographie, Schwermineralchemie, Illitkristallinität, RFA, XRD, SEM, KL, EMP. Die paläozoische geodynamische Entwicklung des Sedimentationsbeckens der Westkarawanken stellt sich folgendermaßen dar: Während des Alt- und älteren Jungpaläozoikum herrschte eine passive Kontinentalrandsituation mit sich verstärkender Dehnungstektonik. Die Extension erreichte im jüngeren Oberdevon bis älteren Unterkarbon ihren Höhepunkt. Während die ältere Hochwipfel-Sedimentation noch in einem transtensionalen Regime stattfand, wurden die jüngeren Teile der Hochwipfel-Formation in einem transpressionalen Regime abgelagert. Die Schüttungen aus den vorwiegend kristallinen und untergeordnet sedimentären Liefergebieten wurden durch Randbecken und tektonische Hochzonen zurückgehalten und nachfolgend durch „bypass“-Kanäle in das Hochwipfel-Becken verfrachtet. Die Auernig-Formation wurde winkeldiskordant auf den Hochwipfel-Sedimenten abgelagert. Die geodynamische Entwicklung der Karawanken während des Jungpaläozoikum läßt sich in einem „Mega-Transform“-Modell darstellen, bei dem der Sedimentationsraum der Hochwipfel-Formation als „pull-apart“-ähnliche Beckenbildung eines „strike-slip“-Kontinentalrandes zwischen Gondwana und einem alpinen Terran angesehen werden kann.This study focusses on the Carboniferous sediments of the Western Karawanken Mountains (Austria/Slovenia/Italy). Based on sedimentological, petrographical and geochemical provenance analysis, a model for the Carboniferous evolution of the sedimentary basin of the Western Karawanken Mountains and the geodynamic situation during the Upper Paleozoic time will be proposed. The following methods were applied: thin section petrography, chemistry of heavy minerals, Illite crystallinity, XRF, XRD, SEM, CL, EMP. The Paleozoic geodynamic evolution of the sedimentary basin of the Western Karawanken Mountains can be described as follows: During the Early and lower Late Paleozoic, a passive continental margin situation with advancing extensional tectonics exists. The extension reached its climax during the upper Late Devonian to lower Early Carboniferous. Whereas the lower Hochwipfel sedimentation took place in an transtensional regime, the upper portions of the Hochwipfel Formation were deposited in a transpressional regime. The sedimentary input from the basement and sedimentary source areas was retained and trapped by marginal basins and tectonic highs, and subsequently transported via bypass-channels into the Hochwipfel basin. The Auernig Formation was deposited above the Hochwipfel sediments with an angular unconformity. The geodynamic evolution of the Karawanken Mountains during the Late Paleozoic can be explained by a "mega-transform" model, where the sedimentary basin of the Hochwipfel Formation can be considered as a pull-apart basin at the strike-slip continental margin between Gondwana and an Alpine terrane

Petrographische und geochemische Provenanz-Indikatoren der Hochwipfel Formation (Karbon, Karawanken) / Petrographie and geochemical provenance indicators of the Carboniferous Hochwipfel Formation (Karawanken Mountains)

In the eastern Karawanken Mountains, the siliciclastic sedimentary succession of the Hochwipfel Formation was deposited within a narrow marginal basin of the western Paleotethys. Variations of detrital sandstone modes define four petrofacies types, and allow the succession to be stratigraphically divided into Lower and Upper Hochwipfel Formation. Petrographical and geochemical provenance analysis indicate that the basal quartz-rich sandstones derived mainly from the Intraalpine Terrane in the north and the passive Gondwana margin in the south. In the sediments of the Upper Hochwipfel Formation, an increase of (meta)sedimentary as well as of magmatic lithoclasts is discernible indicating a convergent tectonic situation and increased sediment supply derived from a magmatic arc. Zusammenfassung: Die klastische Sedimentabfolge der karhonen HochwipfelFormation der Ostkarawanken wurde in einem schmalen Randbecken der westlichen Paläotethys abgelagert. Auf Grund der Modalzusammensetzung der Sandsteine lassen sich vier Petrofaziestypen unterscheiden, und die sedimentäre Abfolge in eine Untere und eine Obere Hochwipfel-Formation gliedern. Petrographische und geochemische Provenienz-Indikatoren deuten darauf hin, dass die basalen quarzreichen Sandsteine der unteren Hochwipfel-Formation überwiegend von dem nördlich gelegenen Intraalpinen Terran bzw. dem südlich gelegenen passiven Kontinentalrand Gondwanas stammen. In den Sedimenten der oberen Hochwipfel-Formation ist eine Zunahme von (meta)sedimentären Lithoklasten sowie magmatischen Gesteinsbruchstücken zu beobachten. Dies zeigt den Übergang zu einer konvergenten tektonischen Situation und den verstärkten Sedimenteintrag aus einem magmatischen Bogen an

Antithrombotic Treatment of Embolic Stroke of Undetermined Source

Background and Purpose- The RE-SPECT ESUS trial (Randomized, Double-Blind, Evaluation in Secondary Stroke Prevention Comparing the Efficacy and Safety of the Oral Thrombin Inhibitor Dabigatran Etexilate Versus Acetylsalicylic Acid in Patients With Embolic Stroke of Undetermined Source) tested the hypothesis that dabigatran would be superior to aspirin for the prevention of recurrent stroke in patients with embolic stroke of undetermined source. This exploratory subgroup analysis investigates the impact of age, renal function (both predefined), and dabigatran dose (post hoc) on the rates of recurrent stroke and major bleeding. Methods- RE-SPECT ESUS was a multicenter, randomized, double-blind trial of dabigatran 150 or 110 mg (for patients aged ≥75 years and/or with creatinine clearance 30 to <50 mL/minute) twice daily compared with aspirin 100 mg once daily. The primary outcome was recurrent stroke. Results- The trial, which enrolled 5390 patients from December 2014 to January 2018, did not demonstrate superiority of dabigatran versus aspirin for prevention of recurrent stroke in patients with embolic stroke of undetermined source. However, among the population qualifying for the lower dabigatran dose, the rate of recurrent stroke was reduced with dabigatran versus aspirin (7.4% versus 13.0%; hazard ratio, 0.57 [95% CI, 0.39-0.82]; interaction P=0.01). This was driven mainly by the subgroup aged ≥75 years (7.8% versus 12.4%; hazard ratio, 0.63 [95% CI, 0.43-0.94]; interaction P=0.10). Stroke rates tended to be lower with dabigatran versus aspirin with declining renal function. Risks for major bleeding were similar between treatments, irrespective of renal function, but with a trend for lower bleeding rates with dabigatran versus aspirin in older patients. Conclusions- In subgroup analyses of RE-SPECT ESUS, dabigatran reduced the rate of recurrent stroke compared with aspirin in patients qualifying for the lower dose of dabigatran. These results are hypothesis-generating. Aspirin remains the standard antithrombotic treatment for patients with embolic stroke of undetermined source. Registration- URL: https://www.clinicaltrials.gov; Unique identifier: NCT02239120

Antithrombotic Treatment of Embolic Stroke of Undetermined Source: RE-SPECT ESUS Elderly and Renally Impaired Subgroups.

Background and Purpose- The RE-SPECT ESUS trial (Randomized, Double-Blind, Evaluation in Secondary Stroke Prevention Comparing the Efficacy and Safety of the Oral Thrombin Inhibitor Dabigatran Etexilate Versus Acetylsalicylic Acid in Patients With Embolic Stroke of Undetermined Source) tested the hypothesis that dabigatran would be superior to aspirin for the prevention of recurrent stroke in patients with embolic stroke of undetermined source. This exploratory subgroup analysis investigates the impact of age, renal function (both predefined), and dabigatran dose (post hoc) on the rates of recurrent stroke and major bleeding. Methods- RE-SPECT ESUS was a multicenter, randomized, double-blind trial of dabigatran 150 or 110 mg (for patients aged ≥75 years and/or with creatinine clearance 30 to <50 mL/minute) twice daily compared with aspirin 100 mg once daily. The primary outcome was recurrent stroke. Results- The trial, which enrolled 5390 patients from December 2014 to January 2018, did not demonstrate superiority of dabigatran versus aspirin for prevention of recurrent stroke in patients with embolic stroke of undetermined source. However, among the population qualifying for the lower dabigatran dose, the rate of recurrent stroke was reduced with dabigatran versus aspirin (7.4% versus 13.0%; hazard ratio, 0.57 [95% CI, 0.39-0.82]; interaction P=0.01). This was driven mainly by the subgroup aged ≥75 years (7.8% versus 12.4%; hazard ratio, 0.63 [95% CI, 0.43-0.94]; interaction P=0.10). Stroke rates tended to be lower with dabigatran versus aspirin with declining renal function. Risks for major bleeding were similar between treatments, irrespective of renal function, but with a trend for lower bleeding rates with dabigatran versus aspirin in older patients. Conclusions- In subgroup analyses of RE-SPECT ESUS, dabigatran reduced the rate of recurrent stroke compared with aspirin in patients qualifying for the lower dose of dabigatran. These results are hypothesis-generating. Aspirin remains the standard antithrombotic treatment for patients with embolic stroke of undetermined source. Registration- URL: https://www.clinicaltrials.gov; Unique identifier: NCT02239120

Visits to tourist attractions 1998

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