2,216 research outputs found
How large dimension guarantees a given angle?
We study the following two problems:
(1) Given and \al, how large Hausdorff dimension can a compact set
A\su\Rn have if does not contain three points that form an angle \al?
(2) Given \al and \de, how large Hausdorff dimension can a %compact
subset of a Euclidean space have if does not contain three points that
form an angle in the \de-neighborhood of \al?
An interesting phenomenon is that different angles show different behaviour
in the above problems. Apart from the clearly special extreme angles 0 and
, the angles and also play special
role in problem (2): the maximal dimension is smaller for these special angles
than for the other angles. In problem (1) the angle seems to behave
differently from other angles
A Phase Transition for Circle Maps and Cherry Flows
We study weakly order preserving circle maps with a flat interval.
The main result of the paper is about a sharp transition from degenerate
geometry to bounded geometry depending on the degree of the singularities at
the boundary of the flat interval. We prove that the non-wandering set has zero
Hausdorff dimension in the case of degenerate geometry and it has Hausdorff
dimension strictly greater than zero in the case of bounded geometry. Our
results about circle maps allow to establish a sharp phase transition in the
dynamics of Cherry flows
Digestibility Estimates Based on a Grass Growth Model Are Distributed via Internet to Finnish Farmers
Optimising the harvesting time of grass in primary growth is difficult under Finnish climatic conditions, because the digestibility of grass decreases on average by 0.5 percentage units daily. We constructed a model based on cumulative temperature and geographical location which estimates the digestibility of grass. This model is used to produce estimates utilising real time weather information. The estimates are presented as a map, which is revised daily. Farmers have free access to the maps via Internet
Sixty Years of Fractal Projections
Sixty years ago, John Marstrand published a paper which, among other things,
relates the Hausdorff dimension of a plane set to the dimensions of its
orthogonal projections onto lines. For many years, the paper attracted very
little attention. However, over the past 30 years, Marstrand's projection
theorems have become the prototype for many results in fractal geometry with
numerous variants and applications and they continue to motivate leading
research.Comment: Submitted to proceedings of Fractals and Stochastics
Higher-dimensional multifractal value sets for conformal infinite graph directed Markov systems
We give a description of the level sets in the higher dimensional
multifractal formalism for infinite conformal graph directed Markov systems. If
these systems possess a certain degree of regularity this description is
complete in the sense that we identify all values with non-empty level sets and
determine their Hausdorff dimension. This result is also partially new for the
finite alphabet case.Comment: 20 pages, 1 figur
Hyvinvoinnin turvaamisen rajat : Näköaloja talouskriisiin ja hyvinvointivaltion kehitykseen Suomessa
Miten syksyllä 2008 alkanut globaali talouskriisi vaikuttaa pitkällä aikavälillä suomalaiseen hyvinvointivaltioon? Jos olisimme antiikin Kreikassa, voisimme mennä Delfoin oraakkelin luo Apollonin temppeliin ja esittää tämän kysymyksen ennuspapittarelle. Eräänä lokakuun päivänä 2009 Kelan tiloihin kokoontui joukko suomalaisia hyvinvointivaltion huippuasiantuntijoita. He kertoivat julkisen talouden, kansalaisten toimeentulon ja terveyden näkökulmista kolmelle ”professori-oraakkelille” eli tanskalaiselle Nina Smithille, ruotsalaiselle Johan Fritzellille ja saksalaisille Karl Hinrichsille Suomen kokemuksista edellisestä, 1990-luvun alun lamasta, sen jälkeisestä kehityksestä sekä omista tulevaisuuden arvioistaan. Seuraavana päivänä oraakkelit lausuivat ennustuksensa, joka paljastetaan tässä raportissa.10,00 euro
Temperature and pressure-induced spin-state transitions in LaCoO3
We report the continuous variation of the spin moment of cobalt in LaCoO3
across its temperature and pressure-induced spin transitions evidenced with
K\beta emission spectra. The first thermal transition is best described by a
transition to an orbitally nondegenerate intermediate spin (S=1) state. In
parallel, continuous redistribution of the 3d electrons is also indicated by
partial fluorescence yield X-ray absorption spectra. At high pressure, our
study confirms that the material becomes low spin between 40 and 70 kbar at
room temperature
Comments on ``The first detections of the Extragalactic Background Light at 3000, 5500, and 8000 A'' by Bernstein, Freedman and Madore
A critical discussion is presented of the data analysis applied by Bernstein,
Freedman and Madore (2002 ApJ, 571, 56; and ApJ 571, 85) in their measurement
of the Extragalactic Background Light. There are questionable assumptions in
the analysis of the ground-based observations of the Zodiacal Light. The
modeling of the Diffuse Galactic Light is based on an underestimated value of
the dust column density along the line of sight. Comparison with the previously
presented results from the same observations reveals a puzzling situation: in
spite of a large difference in the atmospheric scattered light corrections the
derived Extragalactic Background Light values are exactly the same. The claim
of the paper of a ``detection of the Extragalactic Background Light'' appears
premature.Comment: 6 pages, accepted for Ap
Lipschitz equivalence of subsets of self-conformal sets
We give sufficient conditions to guarantee that if two self-conformal sets E
and F have Lipschitz equivalent subsets of positive measure, then there is a
bilipschitz map of E into, or onto, F
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