6,080 research outputs found
The economic structure of russian towns in the second half of the 18th and the first half of the 19th centuries
Der vorliegende Beitrag beschreibt die Entwicklung der russischen Stadt von 1760 bis 1850 mittels der folgenden funktionalen Klassifikation: (1) eine Stadt durch 'offizielle' Definition (2); ein kommerzielles und industrielles Zentrum (3); ein industriell-kommerzielles oder ein militärisch-administratives Zentrum oder die Kombination von beidem (4); ein industriell-kommerzielles Zentrum mit einer 'bürgerlich-städtischen' Gemeinschaft. Die Analyse zeigt, daß der vorherrschende Typ für den beschriebenen Zeitraum die am ländlichen Umfeld orientierte militärisch-administrative Stadt war. Erst ab der Mitte des vorigen Jahrhunderts entwickelte sich der vierte Typ. (pmb)'The economic structure of Russian towns in the second part of the 18th and first part of the 19th centuries is analysed. The author emploies a functional approach to classify towns according to their economic types in the 1760s, 1790s and 1850s. The functional approach of the classification of towns allowed to embrace all historically and geografically diverse types of towns, avoiding overestimations of some types of activities and underestimation of the other. The analysis shows that in the Russian towns according to their functions the prevailing type of the urban settlement was the agrarian, administrative-military town. The conversion of the town from the mainly agrarian into mainly industrial commercial centre occured only by the mid-19th century.' (author's abstract
Stabilization of dipole solitons in nonlocal nonlinear media
We address the stabilization of dipole solitons in nonlocal nonlinear
materials by two different approaches. First, we study the properties of such
solitons in thermal nonlinear media, where the refractive index landscapes
induced by laser beams strongly depend on the boundary conditions and on the
sample geometry. We show how the sample geometry impacts the stability of
higher-order solitons in thermal nonlinear media and reveal that dipole
solitons can be made dynami-cally stable in rectangular geometries in contrast
to their counterparts in thermal samples with square cross-section. Second, we
discuss the impact of the saturation of the nonlocal nonlinear response on the
properties of multipole solitons. We find that the saturable response also
stabi-lizes dipole solitons even in symmetric geometries, provided that the
input power exceeds a criti-cal value.Comment: 29 pages, 8 figures, to appear in Phys. Rev.
Is Strong Gravitational Radiation predicted by TeV-Gravity?
In TeV-gravity models the gravitational coupling to particles with energies
E\sim m_{Pl} \sim 10 TeV is not suppressed by powers of ultra-small ratio
E/M_{Pl} with M_{Pl} \sim 10^{19} GeV. Therefore one could imagine strong
synchrotron radiation of gravitons by the accelerating particles to become the
most pronounced manifestation of TeV-gravity at LHC. However, this turns out to
be not true: considerable damping continues to exist, only the place of
E/M_{Pl} it taken by a power of a ratio \theta\omega/E, where the typical
frequency \omega of emitted radiation, while increased by a number of
\gamma-factors, can not reach E/\vartheta unless particles are accelerated by
nearly critical fields. Moreover, for currently available magnetic fields B
\sim 10 Tesla, multi-dimensionality does not enhance gravitational radiation at
all even if TeV-gravity is correct.Comment: 7 pages, LaTe
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