Search results for "GEOM"
showing 10 items of 6506 documents
Guano-related phosphate-rich minerals in European caves
2019
International audience; Guano is a typical deposit found in caves derived from the excretions of bats and in minor cases of birds. These organic deposits decompose and form a series of acid fluids and gases that can interact with the minerals, sediments, and rocks present in the cave. Over sixty phosphates are known and described from caves, but guano decay also often leads to the formation of nitrates and sulfates. In this study twenty-two European caves were investigated for their guano-related secondary minerals. Using various analytical techniques, seventeen phosphates, along with one sulfate (gypsum), were recognized as secondary products of guano decay. Among those minerals, some are …
Modéliser un demi-cercle et autres questions de poids nuls
2018
National audience; Les courbes de Bézier rationnelles avec des points pondérés peinent à prendre en compte certaines situations élémentaires comme la modélisation d'un demi-cercle avec une courbe de degré 2. Dans cet article nous mon-trons comment l'utilisation de courbes de Bézier rationnelles avec des points massiques résout ce problème. Plus largement, nous montrons aussi que la formulation usuelle de Bézier rationnelles n'est pas complète.
Introduction à la modélisation de l'écriture manuscrite par des courbes Bézier Rationnelles massiques
2019
National audience; L’article est une introduction à la modélisation de l’écriture manuscrite. La représentation de l’écriture cursive in- terfère, selon l’approche hors ligne ou en ligne, sur la robustesse des algorithmes de reconnaissance des caractères manuscrits, de l’identification des auteurs et de leur signature. Les caractéristiques de base de l’écriture cursive que sont les traits et leur inclinaisons, les boucles, les pleins et déliés peuvent être modélisés par des courbes. Des méthodes existent. Elles reposent sur les B-splines et leur points de contrôle. Dans un premier temps, des traits, les auteurs proposent une modélisation, rebroussements, boucles, arrondis, pleins et déliés.…
Some remarks on Hilbert's (Weak) Nullstellensatz
2011
Certain remarks are provided related to weak nullstellensatz exploiting some problems proposed in Fulton’s book entitled “An Introduction to Algebraic Geometry” and elementary notions of Functional Analysis.
Oscillation of Second-Order Neutral Differential Equations
2013
Author's version of an article in the journal: Funkcialaj Ekvacioj. Also available from the publisher at: http://www.math.kobe-u.ac.jp/~fe/ We study oscillatory behavior of a class of second-order neutral differential equations relating oscillation of these equations to existence of positive solutions to associated first-order functional differential inequalities. Our assumptions allow applications to differential equations with both delayed and advanced arguments, and not only. New theorems complement and improve a number of results reported in the literature. Two illustrative examples are provided.
El Paleolítico Medio y Superior en la desembocadura del río Millars (Castelló). Geocronología de las terrazas pleistocenas y estudio morfotécnico de …
2011
Los recientes trabajos geoarqueológicos llevados a cabo en el tramo final del rio Millars (Castelló), concretamente en la zona próxima a su desembocadura, han proporcionado datos geomorfológicos y geocronológicos de interés. Las dataciones numéricas por OSL indican el desarrollo de las terrazas bajas del río (T5 y T6) en el MIS 2, entre 25.000 y 21.000 años B.P. aproximadamente. Estos datos permiten contextualizar los conjuntos del Paleolítico Medio y Superior existentes, cuyo análisis morfotécnico se incluye en el presente estudio.
Quasiconformal Jordan Domains
2020
We extend the classical Carath\'eodory extension theorem to quasiconformal Jordan domains $( Y, d_{Y} )$. We say that a metric space $( Y, d_{Y} )$ is a quasiconformal Jordan domain if the completion $\overline{Y}$ of $( Y, d_{Y} )$ has finite Hausdorff $2$-measure, the boundary $\partial Y = \overline{Y} \setminus Y$ is homeomorphic to $\mathbb{S}^{1}$, and there exists a homeomorphism $\phi \colon \mathbb{D} \rightarrow ( Y, d_{Y} )$ that is quasiconformal in the geometric sense. We show that $\phi$ has a continuous, monotone, and surjective extension $\Phi \colon \overline{ \mathbb{D} } \rightarrow \overline{ Y }$. This result is best possible in this generality. In addition, we find a n…
Didáctica de la Geometría, la Medida y la Probabilidad y la Estadística
2020
Manual para la asignatura Didáctica de la Geometría, la Medida y la Probabilidad y la Estadística del grado de Maestro/a en Educación Primaria (cuarto curso).
Ceramic Production in the Indigenous Settlement of Entella (Western Sicily) During the Archaic Age
2010
Indigenous fine tablewares (both plain and with painted geometric patterns/decorations) were widely diffused in western and central Sicily between the seventh and the fifth centuries BC (Gargini 1995; Spatafora 1996; Trombi 1999; Campisi 2003 However, the considerable recurrence of shapes and decorative subjects inhibits the identification of specific production centres merely on the basis of stylistic and morphological analyses. Therefore, the extent of the distribution of objects manufactured in different workshops cannot be fully appreciated, and the network of ceramic trade in Archaic Sicily is acknowledged only in terms of the relationships between the Phoenician and Greek colonies and…
Lenses on very curved zones of a singular line field of ${\mathbb C}^2$ or of a singular plane field of ${\mathbb C}^3$
2020
We renormalize, using suitable lenses, small domains of a singular holomorphic line field of ${\mathbb C}^2$ or plane field of ${\mathbb C}^3$ where the curvature of a plane-field is concentrated. At a proper scale the field is almost invariant by translations. When the field is integrable, the leaves are locally almost translates of a surface that we will call {\it profile}. When the singular rays of the tangent cone (a generalization to a plane-field of the tangent cone of a singular surface is defined) are isolated, we obtain more precise results. We also generalize a result of Merle (\cite{Me}) concerning the contact order of generic polar curves with the singular level $f=0$ when $\ome…