1,061 research outputs found
Elliptic curves with torsion group
We exhibit several families of elliptic curves with torsion group isomorphic
to and generic rank at least . Families of this kind have been
constructed previously by several authors: Lecacheux, Kihara, Eroshkin and Woo.
We mention the details of some of them and we add other examples developed more
recently by Dujella and Peral, and MacLeod.
Then we apply an algorithm of Gusi\'c and Tadi\'c and we find the exact rank
over \Q(t) to be 3 and we also determine free generators of the Mordell-Weil
group for each family. By suitable specializations, we obtain the known and new
examples of curves over \Q with torsion and rank , which is the
current record
Existence results for a fourth order partial differential equation arising in condensed matter physics
We study a higher order parabolic partial differential equation that arises
in the context of condensed matter physics. It is a fourth order semilinear
equation whose nonlinearity is the determinant of the Hessian matrix of the
solution. We consider this model in a bounded domain of the real plane and
study its stationary solutions both when the geometry of this domain is
arbitrary and when it is the unit ball and the solution is radially symmetric.
We also consider the initial-boundary value problem for the full parabolic
equation. We summarize our results on existence of solutions in these cases and
propose an open problem related to the existence of self-similar solutions.Comment: To appear in Mathematica Bohemic
Translation of Pronominal Anaphora between English and Spanish: Discrepancies and Evaluation
This paper evaluates the different tasks carried out in the translation of
pronominal anaphora in a machine translation (MT) system. The MT interlingua
approach named AGIR (Anaphora Generation with an Interlingua Representation)
improves upon other proposals presented to date because it is able to translate
intersentential anaphors, detect co-reference chains, and translate Spanish
zero pronouns into English---issues hardly considered by other systems. The
paper presents the resolution and evaluation of these anaphora problems in AGIR
with the use of different kinds of knowledge (lexical, morphological,
syntactic, and semantic). The translation of English and Spanish anaphoric
third-person personal pronouns (including Spanish zero pronouns) into the
target language has been evaluated on unrestricted corpora. We have obtained a
precision of 80.4% and 84.8% in the translation of Spanish and English
pronouns, respectively. Although we have only studied the Spanish and English
languages, our approach can be easily extended to other languages such as
Portuguese, Italian, or Japanese
Inferencia del origen del bovino Criollo Cubano a través del análisis de patri- y matrilinajes
Antes de descubrimiento, no existían bovinos en América. Los primeros, fueron introducidos en la Antillas Mayores (La Española, Puerto Rico, Jamaica y Cuba), y desde allí trasladados al resto de Latinoamérica. Actualmente, existen en Cuba alrededor de 1300 bovinos Criollos, concentrados principalmente en la región oriental. Con el objetivo de analizar el origen materno de esta raza y detectar eventos contemporáneos de flujo génico por vía paterna, se analizó un fragmento de 240 pb del D-loop mitocondrial (mtADN) y 5 microsatélites del cromosoma Y (BTY), en 36 hembras y 21 machos respectivamente. La diversidad genética se estimó mediante el número de haplotipos, el número de sitios polimórficos, el número de diferencias nucleotídicas entre pares de secuencias y el índice de diversidad nucleotídica, mientras que el análisis filogenético se realizó utilizando el método de median joining network. Dicho análisis permitió detectar 15 haplotipos mitocondriales (10 del haplogrupo europeo T3, 3 del africano T1, 1 del cercano oriente T2 y 1 ambiguo T1-T3) y 3 haplotipos en el BTY, ambos del haplogrupo cebuíno Y3. En el mtADN se detectaron 23 sitios polimórficos con una diversidad nucleotídica de 0,014 y 3,36 diferencias medias entre pares de secuencias. En conclusión, la población de bovinos Criollos Cubanos presentó una composición haplotípica mitocondrial comparable a la de otras razas criollas y mediterráneas, hecho que concuerda con su origen histórico. El BTY evidenció altos niveles de introgresion paterna de genes del zebú.Cattle was absent from America before the discovery. Initially, bovine were brought to Greater Antilles (La Española, Puerto Rico, Jamaica and Cuba islands), and in the course of a few years, they were taken from Caribbean islands to the rest of Latin America. Nowadays, Cuban Creole cattle population is about 1300 heads, mainly located in the eastern region of the island. With the aim of analyzing the maternal origin of Cuban Creole cattle and detect possible contemporaneous, male mediated, gene flow, a 240 pb fragment of mitochondrial D-loop (mtDNA) and five microsatellites of Y chromosome (BTY) were studied in 36 dams and 21 sires, respectively. Genetic diversity was evaluated through number of haplotypes, mean number of pairwise differences and nucleotide diversity. The phylogenetic analysis was performed using a median joining. A total of 15 mtDNA haplotypes were detected in the studied population (10 from the European haplogroup T3, 3 from the African T1, 1 from the Nearern East T2, and 1 ambiguous T1-T3). The number of polymorphic sites, the mean nucleotide diversity, and the mean number of pairwise differences were 23, 0.014 and 3.36, respectively. Two patrilinages were detected, both belonging to the Y3 Zebu haplogroup. In conclusion, Cuban Creole cattle population had a mtDNA haplotypic composition similar to the observed in Creole and Mediterranean breeds, what is in concordance with its historical origin. Y chromosome analysis evidenced a male mediated process of zebu introgression.Fil: Liron, Juan Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Acosta, A.. Centro Nacional de Sanidad Agropecuaria. Laboratorio de Genética Molecular; CubaFil: Rogberg Muñoz, Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Uffo, O.. Centro Nacional de Sanidad Agropecuaria. Laboratorio de Genética Molecular; CubaFil: Posik, Diego Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Garcia, J.. Ministerio de la Agricultura. Dirección Nacional de Genética; CubaFil: Peral Garcia, Pilar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Giovambattista, Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; Argentin
Thin and thick cloud top height retrieval algorithm with the Infrared Camera and LIDAR of the JEM-EUSO Space Mission
The origin of cosmic rays have remained a mistery for more than a century.
JEM-EUSO is a pioneer space-based telescope that will be located at the
International Space Station (ISS) and its aim is to detect Ultra High Energy
Cosmic Rays (UHECR) and Extremely High Energy Cosmic Rays (EHECR) by observing
the atmosphere. Unlike ground-based telescopes, JEM-EUSO will observe from
upwards, and therefore, for a properly UHECR reconstruction under cloudy
conditions, a key element of JEM-EUSO is an Atmospheric Monitoring System
(AMS). This AMS consists of a space qualified bi-spectral Infrared Camera, that
will provide the cloud coverage and cloud top height in the JEM-EUSO Field of
View (FoV) and a LIDAR, that will measure the atmospheric optical depth in the
direction it has been shot. In this paper we will explain the effects of clouds
for the determination of the UHECR arrival direction. Moreover, since the cloud
top height retrieval is crucial to analyze the UHECR and EHECR events under
cloudy conditions, the retrieval algorithm that fulfills the technical
requierements of the Infrared Camera of JEM-EUSO to reconstruct the cloud top
height is presently reported.Comment: 5 pages, 6 figures, Atmohead Conference 201
Utilising the Cross Industry Standard Process for Data Mining to reduce uncertainty in the Measurement and Verification of energy savings
This paper investigates the application of Data Mining (DM) to predict baseline energy consumption for the improvement of energy savings estimation accuracy in Measurement and Verification (M&V). M&V is a requirement of a certified energy management system (EnMS). A critical stage of the M&V process is the normalisation of data post Energy Conservation Measure (ECM) to pre-ECM conditions. Traditional M&V approaches utilise simplistic modelling techniques, which dilute the power of the available data. DM enables the true power of the available energy data to be harnessed with complex modelling techniques. The methodology proposed incorporates DM into the M&V process to improve prediction accuracy. The application of multi-variate regression and artificial neural networks to predict compressed air energy consumption in a manufacturing facility is presented. Predictions made using DM were consistently more accurate than those found using traditional approaches when the training period was greater than two months
Pseudiverticulosis múltiple en intestino delgado en un caballo
This paper reports one case of a horse with acute colic syndrome that was referred to the Teaching Hospital Complutense of Madrid. Based on the history, clinical signs and complementary diagnostic tests, a colon displacement was diagnosed. In the exploratory celiotomy, a right dorsal displacement of the large colon and generalized enteritis were found. During the surgery, adhesions all along the small intestine and multiple diverticula of different size in the mesenteric border in portions of the jejunum were also found. Due to these findings and the poor condition of the patient, euthanasia was performed on human grounds. This case report concludes that attending veterinarian should include this uncommon pathology in their differential diagnosis when chronic signs of colic, weight loss or diarrheas are a feature.Describimos el caso clínico de un caballo con síndrome cólico agudo que fue remitido al Hospital Clínico Veterinario Complutense. En base a los datos de la historia clínica, la sintomatología y las pruebas complementarias realizadas, se le diagnosticó un desplazamiento de colon por lo que se decidió proceder a una laparotomía exploratoria en la que se observó un desplazamiento dorsal derecho de la flexura pelviana, una severa enteritis generalizada y una peritonitis séptica. Durante la cirugía también se hallaron adherencias a lo largo de todo el intestino delgado y divertículos de diversas dimensiones en el borde mesentérico en diferentes porciones del yeyuno. Debido a estos hallazgos y a la peritonitis séptica, se decidió llevar a cabo la eutanasia humanitaria intraoperatoria del caballo. Aunque la diverticulosis es una patología infrecuente, debe ser incluida en el diagnóstico diferencial de caballos que presentan cuadros cólicos recurrentes, pérdida de peso o cuadros diarreicos
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