760 research outputs found
Dynamics of abelian subgroups of GL(n, C): a structure's Theorem
In this paper, we characterize the dynamic of every abelian subgroups
of GL(, ), or
. We show that there exists a -invariant, dense open
set in saturated by minimal orbits with a union of at most -invariant vectorial subspaces of
of dimension or on . As a consequence,
has height at most and in particular it admits a minimal set
in .Comment: 16 page
Investigating Diversity in the Banking Sector in Europe: The Performance and Role of Savings Banks. CEPS Paperbacks. June 2009
In the aftermath of the financial crisis, the foundations of modern and innovative financial systems developed over decades have suffered serious damage. This has triggered massive state interventions and has led authorities to revamp the regulatory structures and frameworks. While many voices have called for a return to more traditional approaches to banking and finance, no one has argued the merits of diversity.
This book investigates the merits of a diverse banking system with a special focus on the performance and role of savings banks in selected European countries where they are still prominent (Austria, Germany and Spain) and where they have progressively disappeared (Belgium and Italy). The theoretical and empirical arguments that are developed in this book tend to support the view that it is economically and socially beneficial to have âdual bottom-lineâ institutions, such as savings banks. For those who accept this premise, it would suggest that policy-makers should not take or support actions that could jeopardise this valuable element of the financial system in various countries in Europe and of the emerging integrated European financial system
Linear semigroups with coarsely dense orbits
Let be a finitely generated abelian semigroup of invertible linear
operators on a finite dimensional real or complex vector space . We show
that every coarsely dense orbit of is actually dense in . More
generally, if the orbit contains a coarsely dense subset of some open cone
in then the closure of the orbit contains the closure of . In the
complex case the orbit is then actually dense in . For the real case we give
precise information about the possible cases for the closure of the orbit.Comment: We added comments and remarks at various places. 14 page
Space-time variation of ciliates related to environmental factors in 15 nearshore stations of the Gulf of Gabes
Diversity and structure of ciliate communities in the Gulf of Gabes (Tunisia) were investigated based on a survey of 15 nearshore stations along 237 Km, by monthly sampling over a 1-year. Ciliated protozoa were identiïŹed to genus and/or species level and enumerated. Statistic tools were used to explain the ciliates assemblage. High ciliates species richness from 133 taxa was recorded, including new records of 76 species. This study showed a longitudinal distribution of ciliate communities, which are organized in northern stations (from Tabia to Harbor of Gabes) and southern stations (from Zarrat to Jabiat Haj Ali). The number of taxa increased significantly in northern stations but decreased in the southern. This distribution was mainly influenced by the salinity and phytoplankton abundance. Ciliate taxa were grouped into fives size-classes: 15-30 ”m, 30-50 ”m, 50-100 ”m, 100-200 ”m and >200 ”m. In terms of abundance, most abundant size groups were small ciliates (15-30 ÎŒm) accounted from 15 to 79 %, while the greatest biomass contribution came from the 50-100 ÎŒm size classes. We thus conclude high diversity of ciliates communities that showed a geographical distribution influenced by abiotic and biotic factors along the coast of Gulf of Gabes
Contribution a lâĂ©tude physicochimique de lâĂ©cosystĂšme lacustre Dayet Aoua au Maroc
LâĂ©tude consiste Ă la dĂ©termination de la qualitĂ© physicochimique des eaux du lac Dayet Aoua situĂ© dans le Moyen Atlas au Maroc juste aprĂšs son dernier dessĂ©chement survenu en Ă©tĂ© 2002. Les rĂ©sultats dâanalyse obtenus au cours de la pĂ©riode dâĂ©tude comprise entre fĂ©vrier et juillet 2005, montrent que les eaux du lac sont bicarbonatĂ©es calciques et magnĂ©siennes, dures Ă trĂšs dures. La duretĂ© dĂ©pend essentiellement des ions magnĂ©sium. Les analyses des formes azotĂ©es et des orthophosphates des eaux du lac donnent des valeurs trĂšs faibles, et ne dĂ©cĂšlent aucune sorte de pollution de type organique pouvant engendrer son eutrophisation, ce qui permet de le classeractuellement parmi les lacs oligotrophes.Mots-clĂ©s : lac, physico-chimie, pollution organique, oligotrophe
Local and regional factors influencing zooplankton communities in the connected Kasseb Reservoir, Tunisia
Associations between zooplankton community structure and abiotic (temperature, dissolved oxygen, turbidity, nutriments) and biotic factors (chlorophyll a and phytoplankton community) were examined, in Kasseb Reservoir, northern Tunisia. Samples were taken bimonthly from July to December 2002 at 3 sampling stations (deepest station: Station 1, Brik River: Station 2 and MâZaz Stama River: Station 3). From our results it is evident that zooplankton exhibit seasonally and spatially heterogeneous distribution. The highest density of zooplankton was recorded in September at a depth of 5 m (10.8 Ă 103 ind·l-1). At Station 1 cyclopoid copepods (65% of total abundance) were the most abundant group followed by Cladocera (21% of total abundance). At Station 2 (93% of total abundance) and Station 3 (98% of total abundance) cyclopoid copepodswere numerically dominant throughout the study period. Canonical correspondence analysis (CCA) was used to estimate the influence of abiotic and biotic factors in structuring the zooplankton assemblage. Zooplankton abundance was negatively correlated with turbidity (r= -0.381,
Pyrene bisiminopyridine ligand and its zinc complex
The synthesis of a pyrene bisiminopyridine ligand L was successfully accomplished by condensation between 1-aminopyrene and 2,6-pyridinecarboxaldehyde. The complexation of L with zinc triflate afforded a neutral metal complex formulated as [Zn(H2O)LCF3SO3)2].2Et2O. In the complex, the ligand is coordinated to zinc(II) through its three nitrogen atoms which form a distorted octahedral environment together with three oxygen atoms, two from the triflate anions and one from aqua ligand. Both compounds have been characterized using NMR, elemental analysis, mass spectrometry, electronic absorption (UV-Vis) and infrared. Luminescence properties of these compounds show an emission maxima at 412Â nm, indicating a pyrene monomer emission
Hamatum osteoblastoma
SummaryWe report the case of an osteoblastoma of the hamate bone that was successfully treated by curettage. This tumor is very rare in a carpal bone and only nine cases have been reported in the literature. Pathological examination is mandatory before treatment due to the lack of distinctive clinical and radiological features. Osteoblastomas are benign, but potentially aggressive bone tumors. Treatment of the lesion may either be a conservative âintralesional resectionâ or radical âwide en bloc resectionâ. The latter option, which has non-negligible functional consequences in the wrist, should be reserved for recurrence after curettage but may also be considered a primary immediate alternative for aggressive forms
Magnetic properties in amorphous Co95ÂxDyxZr5 thin films
Amorphous Co95-xDyxZr5 thin films were prepared by RF sputtering and their magnetic properties were studied as a function of temperature and for the composition range 0<x<30. The mean field theory has been used to explain the temperature dependence of the magnetization. The exchange interactions between Co-Co and Dy-Co atom pairs have been evaluated. The magnetic phase diagrams are presented.Amorphous Co95-xDyxZr5 thin films were prepared by RF sputtering and their magnetic properties were studied as a function of temperature and for the composition range 0<x<30. The mean field theory has been used to explain the temperature dependence of the magnetization. The exchange interactions between Co-Co and Dy-Co atom pairs have been evaluated. The magnetic phase diagrams are presented
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