5,275 research outputs found
Universal Indexes for Highly Repetitive Document Collections
Indexing highly repetitive collections has become a relevant problem with the
emergence of large repositories of versioned documents, among other
applications. These collections may reach huge sizes, but are formed mostly of
documents that are near-copies of others. Traditional techniques for indexing
these collections fail to properly exploit their regularities in order to
reduce space.
We introduce new techniques for compressing inverted indexes that exploit
this near-copy regularity. They are based on run-length, Lempel-Ziv, or grammar
compression of the differential inverted lists, instead of the usual practice
of gap-encoding them. We show that, in this highly repetitive setting, our
compression methods significantly reduce the space obtained with classical
techniques, at the price of moderate slowdowns. Moreover, our best methods are
universal, that is, they do not need to know the versioning structure of the
collection, nor that a clear versioning structure even exists.
We also introduce compressed self-indexes in the comparison. These are
designed for general strings (not only natural language texts) and represent
the text collection plus the index structure (not an inverted index) in
integrated form. We show that these techniques can compress much further, using
a small fraction of the space required by our new inverted indexes. Yet, they
are orders of magnitude slower.Comment: This research has received funding from the European Union's Horizon
2020 research and innovation programme under the Marie Sk{\l}odowska-Curie
Actions H2020-MSCA-RISE-2015 BIRDS GA No. 69094
Milne-Eddington inversions of the He I 10830 {\AA} Stokes profiles: Influence of the Paschen-Back effect
The Paschen-Back effect influences the Zeeman sublevels of the He I multiplet
at 10830 {\AA}, leading to changes in strength and in position of the Zeeman
components of these lines. We illustrate the relevance of this effect using
synthetic Stokes profiles of the He I 10830 {\AA} multiplet lines and
investigate its influence on the inversion of polarimetric data. We invert data
obtained with the Tenerife Infrared Polarimeter (TIP) at the German Vacuum
Tower Telescope (VTT). We compare the results of inversions based on synthetic
profiles calculated with and without the Paschen-Back effect being included. We
find that when taking into account the incomplete Paschen-Back effect, on
average 16% higher field strength values are obtained. We also show that this
effect is not the main cause for the area asymmetry exhibited by many He I
10830 Stokes V-profiles. This points to the importance of velocity and magnetic
field gradients over the formation height range of these lines.Comment: Accepted for publication in A&A on Jun 12th 200
Micobacteriosis en una tortuga mediterránea
Se describe un caso de Micobacteriosis en una tortuga mediterránea mantenida en cautividad. Se presenta el cuadro clínico y los hallazgos microbiológicos y anatornopatológicos, haciendo hincapié en las posibles repercusiones epidemiológicas para la salud humana.A case of Mycobacteriosis in a captive Hermann Tortoise is described. The clinical, microbiological and anatomopathological findings are presented With especial reference to posible consequences for human health
Análisis de las diferencias de género en la elección de estudios universitarios
Esta investigación analiza el interés del
alumnado de Bachillerato por realizar una carrera universitaria
concreta y los motivos de dicha elección según
la variable sexo. Se utilizó un diseño de investigación
transversal con encuesta. Los resultados muestran
que las chicas eligen principalmente carreras de Humanidades,
Ciencias Experimentales, Ciencias Sociales,
Jurídicas y de la Salud y sus principales motivos de elección
son porque les gusta, por vocación y para ayudar a
otras personas, mientras que ellos se decantan por estudios
técnicos para ganar un buen sueldo. Se discute la
pertinencia de una orientación vocacional individualizada
que garantice la igualdad de oportunidades
Fracturas diafisarias de húmero en adultos: estudio retrospectivo de 53 casos
Se estudian retrospectivamente 53 pacientes adultos con fractura diafisaria de
húmero, 36 de los cuales siguieron el tratamiento ortopédico funcional. En otros 17 casos,
pacientes politraumatizados o con fracturas de tercio medio transversas, realizamos tratamiento
quirúrgico. La edad media de los pacientes fue 48 ± 2 2 años. Se afectó más el lado derecho,
siendo el antecedente etiológico más frecuente el accidente casual. No hubo diferencia entre
el tiempo de consolidación con el tratamiento ortopédico-funcional (60 ± 14 días) y el tratamiento
quirúrgico (56 ±1 2 días). Como complicaciones hubo 7 pseudoartrosis (4 tras tratamiento
ortopédico-funcional y 3 tratamiento quirúrgico). La edad media de los pacientes con
pseudoartrosis fue superior a la de los pacientes con consolidación completa. Ocho casos cursaron
con lesión del nervio radial, obteniendo una recuperación funcional del 100% en un
tiempo medio de 38 ± 30 semanas. Valorando los resultados con arreglo a los criterios de Gayet,
hemos obtenido un 80% de buenos y muy buenos resultados con tratamiento ortopédico
funcional y un 70% con tratamiento quirúrgico.Fifty three adult patients with fracture of the humeral shaft were retrospectively
studied. Orthopaedic-functional treatment was applied in 36 cases. Seventeen patients with
either multiple injuries or transverse middle-shaft fractures were surgically treated. The mean
age of patients was 48 ± 21 years. Right side was most frecuently affected and casual fall was
the predominated etiology. There were no differences regarding the average consolidation period
between fractures treated conservatively (60 ± 14 days) and those undergoing surgery (56 ± 12
days). As complications, there were 7 monounions (4 conservative and 3 operative treatment).
The mean age of patients with non-unions was higther than those with complete fracture consolidation.
Radial nerve injury was seen in 8 cases. In all there patients, a complete functional
were recovery was obtained with a mean average time of 38 ± 30 weeks. When evaluating functional
results according to Gayet, satisfactory results were found in 80 per cent of patients with
conservative treatment and 70 per cent of those surgically treated
La comunicación desde una perspectiva sociocultural: secuencias de una conversación académica
En el marco del XV Encuentro del Consejo Nacional para la Enseñanza y la Investigación de las Ciencias de la Comunicación (CONEICC), celebrado en la Universidad Iberoamericana de la Ciudad de México en octubre de 2010, se realizó la presentación del libro de Raúl Fuentes “La comunicación desde una perspectiva sociocultural, acercamientos y provocaciones 1997-2007” publicado por el ITESO casi dos años antes. La presentación dio pie a una estimulante conversación en público entre el autor, el doctor Manuel Alejandro Guerrero, coordinador del Departamento de Comunicación de la Universidad Iberoamericana, y la maestra Gabriela Flores, académica de la misma institución. Gracias a la recuperación del registro digital, la conversación pudo ser reconstruida por escrito.ITESO, A.C
Aplasia del arco posterior del Atlas
Las anomalías congénitas del arco posterior del Atlas son poco frecuentes. Se
presenta el caso de una paciente, que tras sufrir un accidente se diagnosticó de aplasia parcial
del atlas. Esta lesión es considerada como una variante anatómica benigna de la región cráneovertebral.
Se expone el desarrollo y el significado de esta anomalía.Congenital anomalies of the posterior arch of the atlas are uncommon. This
paper presents the case of a patient who, as result of an accident, was diagnosed as having a
congenital partial agenesia of the posterior arch of the atlas. This finding is considered as a
benign anatomical variation of the craniovertebral junction region. The development and clinical
significance of this anomaly are discussed
Enhanced quench propagation in 2G-HTS coils co-wound with stainless steel or anodised aluminium tapes
Early quench detection and thermal stability of superconducting coils are of great relevance for practical applications. Magnets made with second generation high temperature superconducting (2G-HTS) tapes present low quench propagation velocities and therefore slow voltage development and high local temperature rises, which may cause irreversible damage. Since quench propagation depends on the anisotropy of the thermal conductivity, this may be used to achieve an improvement of the thermal stability and robustness of 2G-HTS coils. On pancake type coils, the thermal conductivity along the tapes (coil's azimuthal direction) is mostly fixed by the 2G-HTS tape characteristics, so that the reduction of anisotropy relies on the improvement of the radial thermal conductivity, which depends on the used materials between superconducting tapes, as well as on the winding and impregnation processes. In this contribution, we have explored two possibilities for such anisotropy reduction: by using anodised aluminium or stainless steel tapes co-wound with the 2G-HTS tapes. For all the analysed coils, critical current distribution, minimum quench energy values and both tangential and radial quench propagation velocities at different temperatures and currents are reported and compared with the results of similar coils co-wound with polyimide (Kapton®) tapes.This work was supported by the Spanish Ministerio de Economía y Competitividad and the European FEDER Program (Projects MAT2011-22719 and ENE-2014-52105-R), and by the Gobierno de Aragón (research group T12).Peer reviewe
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