212 research outputs found
Extensions of BV compactness criteria
Helly's selection theorem provides a criterion for compactness of sets of
single-variable functions with bounded pointwise variation. Fra{\v{n}}kov{\'a}
has given a proper extension of Helly's theorem to the setting of
single-variable regulated functions. We show how a similar approach yields
extensions of the standard compactness criterion for multi-variable functions
of bounded variation
Manifolds counting and class field towers
In [BGLM] and [GLNP] it was conjectured that if is a simple Lie group of
real rank at least 2, then the number of conjugacy classes of (arithmetic)
lattices in of covolume at most is where is an explicit constant computable from the (absolute)
root system of . In this paper we prove that this conjecture is false. In
fact, we show that the growth is at rate . A crucial ingredient of
the proof is the existence of towers of field extensions with bounded root
discriminant which follows from the seminal work of Golod and Shafarevich on
class field towers.Comment: 27 pages, a small change in title, final revision, to appear in Adv.
Mat
Mass transfer in a gas-solid packed column at trickle flow
The height of an overall transfer unit has been evaluated in a gasāsolid packed column at trickle flow by measuring column performance during steady state adsorption experiments. Results have been interpreted with an extraction model: mass transfer and axial dispersion in both phases. Using Bodenstein numbers for the gas and solid phases from a previous investigation the height of a true transfer unit has been calculated.\ud
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The column was filled with dumped Pall rings, the solid phase was a freely flowing catalyst carrier, and the gas phase was air at ambient conditions containing freon-12 as adsorbing component.\ud
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At low gas velocities column performance is entirely determined by axial dispersion but at higher gas velocities mass transfer limitations become important. For conditions of practical importance the height of a true transfer unit corresponds to 4 ā 9 Pall ring layers
Study of the B-Meson Lifetime and the Performance of the Outer Tracker at LHCb
Brand, J.F.J. van den [Promotor]Pellegrino, A. [Copromotor]Raven, H.G. [Copromotor
Concentrations of manganese and iron in some woody and herbs plants
Heavy metals are the substances that indicate environmental pollution. The plants polluted with heavy metals may endanger natural environment and cause health problems in humans. In our multidisciplinary research of the concentrations of pollutants in forest ecosystems and natural environment in Belgrade, we examined the contents of heavy metals essential for plants but harmful in greater concentrations on a long-term basis. The fact that heavy metals manganese and iron are accumulated in plants to the greatest extent focused our work on determination of the level of concentrations of Mn and Fe in the vegetative parts of 8 plant types on three locations on the Avala Mountain and one location in the centre of the city of Belgrade. The analyses of heavy metals contents in plants were performed by the method of flame atomic absorption spectrophotometry. The examination of the existence of important differences between the average values was performed by implementation of Duncanās test for the level of significance of 95%. The current contents of heavy metals in plants in the area of the protected natural resource Avala do not represent danger that would presently cause notable damage to forests but show the tendency of the increase of concentrations. Therefore, this issue should be constantly monitored
Some extinct plant taxa on the territory of Novi Sad and their vulnerability status in Vojvodina and Serbia
Natural habitats on the territory of Novi Sad are almost fully destroyed today, as well as their characteristic plant taxa. The reason for disappearance of natural habitats is the development of suburban communities, which is an irreversible process. Plant taxa, specific for wet, salty, and sandy ecosystems grew on those habitats twenty years ago and earlier. This paper presents the overview of 9 taxa (Suaeda maritima subsp. maritima, Androsace elongata subsp. elongata, Cirsium boujartii subsp. boujartii, Aster sedifolius subsp. canus, Blackstonia perfoliata subsp. serotina, Plantago maritima subsp. maritima, Salvia nutans, Allium angulosum, and Typha schuttleworthii). These taxa presented integral parts of autochthonous flora of Novi Sad. Since some of these taxa were found in the field 21 years ago and some even 93 years ago, they are extinct from the flora of Novi Sad
Neuronal bases of structural coherence in contemporary dance observation
The neuronal processes underlying dance observation have been the focus of an increasing number of brain imaging studies over the past decade. However, the existing literature mainly dealt with effects of motor and visual expertise, whereas the neural and cognitive mechanisms that underlie the interpretation of dance choreographies remained unexplored. Hence, much attention has been given to the Action Observation Network (AON) whereas the role of other potentially relevant neuro-cognitive mechanisms such as mentalizing (theory of mind) or language (narrative comprehension) in dance understanding is yet to be elucidated. We report the results of an fMRI study where the structural coherence of short contemporary dance choreographies was manipulated parametrically using the same taped movement material. Our participants were all trained dancers. The whole-brain analysis argues that the interpretation of structurally coherent dance phrases involves a subpart (Superior Parietal) of the AON as well as mentalizing regions in the dorsomedial Prefrontal Cortex. An ROI analysis based on a similar study using linguistic materials (Pallier et al. 2011) suggests that structural processing in language and dance might share certain neural mechanisms
ALPINSKE MAGMATSKO-METALOGENETSKE FORMACIJE SJEVEROZAPADNIH I SREDIÅ NJIH DINARIDA
In the paper are presented basic geological, petrologieca1, geochemi-cal and mineral deposit data for five main magmatic-metallogenic formations of the northwestern and central Dinarides: (l)The Permo Triassic rifting related andesite-diorite formations; (2) The Jurassic-Lower Cretaceous accretionary (ophiolite) formations; (3) The Upper Cretaceous-Paleogene subduction related basalt-rhyohite formations; (4) The Paleogene collisional granite formations, and (5) The Oligo-cene-Neogene postsubduction andesite formations.
All these magmatic-metallogenic formations originated in different geotectonic settings during the Alpine evolution of the Dinaridic parts of thc Tethys and the postorogenic evolution of the Paratethys and the Pannonian Basin, respectively.U Älanku su prikazani osnovni geoloÅ”ki, petroloÅ”ki, geokemijski i rudnoležiÅ”ni podaci za pet glavnih magmatsko-metalogenetskih formacija sjeverozapadnih i srediÅ”njih Dinarida: (1) permo-trijaske andezit-sko-diuritske riftne formacije; (2) jursko-donjokredne akrecione (ofiolitske) formacije; (3) gornjokredno-paleogene subdukcijske bazalt-riolitne formacije; (4) paleogene kolizijske granitne formacije, i (5) oligocensko-neogene postsubdukcijske andezitske formacije.
Sve te magmatsko-metalogene formacije stvarane su u razliÄitim geotektonskim ambijentima za vrijeme alpinotipne evolucije dinarskih dijelova Tetisa i postorogene evolucije Paratetisa, odnosno bazena Panona
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