1,677 research outputs found
Pedagogical use of cinematic imagery in Augusta Read Thomas\u27s Piano Etudes
This document is a study of Augusta Read Thomas’s piano études from the point of view of mood and atmosphere. These expressive aspects of Thomas’s piano pieces spring out from both the descriptive titles and from the suggestive piano writing. The music analysis of Thomas’s piano études utilizes cinema art as a means to elaborate on musical imagery, based on the cinema’s potential to convey mood and atmosphere. The crossroads between Thomas’s piano études and cinema art affords to create a pedagogical tool as a means for expressive and convincing performances of Thomas’s pieces
Speeds and stance of titanosaur sauropods: analysis of Titanopodus tracks
Speed estimations from trackways of Titanopodus mendozensis González Riga and Calvo provide information about the locomotion of titanosaurian sauropods that lived in South America during the Late Cretaceous. Titanopodus ichnites were found at Agua del Choique, a newly discovered track site in the Loncoche Formation, Late Campanian-Early Maastrichtian of Mendoza, Argentina. This speed study follows the hypothesis of dynamic similarity proposed by Alexander. As a refinement of this method, a complementary equation is presented here based on an articulated titanosaurian specimen collected in strata that are regarded as correlative to those that have yielded Titanopodus tracks (Allen Formation, Neuquén Basin). This analysis indicates that hip height can be estimated as 4.586 times the length of the pes track in derived titanosaurs. With an estimation of the hip height and the stride measurements, the speed is calculated. The study of two wide-gauge trackways indicates that Titanopodus ichnites were produced by mediumsized titanosaurs (hip height of 211-229 cm) that walked at 4.7-4.9 km/h towards the south and southwest, following, in part, a sinuous pathway. These speeds and some taphonomic features of tracks (prominent rims, distorted elongated shapes) indicate the capacity of derived titanosaurs for walking effectively over a very wet and slippery substrate. In the ichnological record, the walking speeds of Titanopodus trackmakers are somewhat faster than those previously inferred for most sauropods. Key words: speed, Sauropoda, Titanopodus, Cretaceous, ArgentinaFil: Gonzalez Riga, Bernardo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Científico Tecnológico Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina. Universidad Nacional de Cuyo; Argentin
Colossal dinosaurs: discoveries and palaeobiology of south American titanosaurs
The number of named titanosaurs has increased dramatically in recent years, with roughly 50 valid species from South America alone. Preservation of relatively complete skeletons in huge sauropods is difficult because its bones suffer a strong disarticulation processes before the burial. This is a consequence of both extrinsic or environmental and intrinsic or biological factors. For instance, in southern Mendoza Province (Argentina), three partially skeletons of an unnamed new titanosaur species show exceptional preservation andare related with both type of factors. Specimen UNCUYO-LD 303 has almost complete axial skeleton (from the first cervical to the last caudalvertebrae, but do not have skull). In a second specimen UNCUYO LD 309, a partially disarticulated skeleton has a relative complete skull whichis preserved below a huge sacrum that protects it and avoids the fluvial transport. In the specimen UNCUYO LD 302, fragments of skull are relatedwith an articulated cervical series, and disarticulated dorsal vertebrae and appendicular bones. These specimens come from the same Plottier Formation (upper Coniacian?lower Santonian) and are separated each other around 50 to 60 meters,but were recovered in different sedimentary facies of the same meandering fluvial system with ephemeral episodes. These and other taphonomicquarries of huge sauropods can allow describing at least two important intrinsic factors related with the bone anatomy: ?structural fragility? and ?weakpoints of disarticulation?. The first one refers to those bones that destroy more easily, such as the case of the characteristic weak and small skull ofthese dinosaurs. The second factor refers to vulnerable joints where the skeleton frequently is disarticulated. This is the case of the atlas-skull, thetarsal-metatarsals and the last caudal centra. From phylogenetic viewpoint, the results of four recent, largely independent analyses support the existenceof a derived titanosaurian lineage distinct from the ?Saltasaurinae line,? which is termed Colossosauria. At present, this clade includes severalgigantic species like Patagotitan, Argentinosaurus, Puertasaurus and Notocolossus. From paleobiological viewpoint, giant sauropods were recorded in different moments of their evolutionary history (like diplodocids in the Jurassic and titanosaurs in the Cretaceous). Unfortunately, our understandingof the gigantism of these animals is at initial stage. Recently, some studies on sauropods indicates that abiotical factors (environmental parameters) cannot easily correlate with their gigantism. In contrast, a ?biological evolutionary cascade model? has been proposed to better explain the huge size. This model can explain the main biological changes of sauropods to reach large bodies, but the coexistence of relatively small and large titanosaur sauropods do not have satisfactory explanation until more accurate morphofunctional and behavioral studies are made. Gregarious behaviors inferred based on titanosaur tracks (e.g. Titanopodus) and nests from Auca Mahuevo (Patagonia) are important adaptions to evaluate in this palaeobiological framework. Finally, in titanosaurs we are in a stage of discovery of new species every years, which is extremely attractive and include an unsuspectedbiological diversity.Fil: Gonzalez Riga, Bernardo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Laboratorio de Dinosaurios.; ArgentinaXXVI Congresso Brasileiro de PaleontologiaUberlandiaBrasilUniversidad Federal de Uberlandi
Bases para el análisis de la problematización de la inseguridad en México
El presente artículo tiene como objetivo presentar algunos rasgos de la forma en cómo se define el problema de inseguridad en México como paso inicial en la formación de una política pública en la materia. Se parte del supuesto de que la seguridad pública puede ser concebida de diversas maneras sin que ello signifique establecer los criterios más adecuados para garantizarla como bien público.El presente artículo tiene como objetivo presentar algunos rasgos de la forma en cómo se define el problema de inseguridad en México como paso inicial en la formación de una política pública en la materia. Se parte del supuesto de que la seguridad pública puede ser concebida de diversas maneras sin que ello signifique establecer los criterios más adecuados para garantizarla como bien público
Spin Weyl Topological Insulators
The quantum nature of electron spin is crucial for establishing topological
invariants in real materials. Since the spin does not in general commute with
the Hamiltonian, some of the topological features of the material can be
extracted from its study. In insulating materials, the spin operator induces a
projected operator on valence states called the spin valence operator. Its
spectrum contains information with regard to the different phases of the spin
Chern class. If the spin valence spectrum is gapped, the spin Chern numbers are
constant along parallel planes thus defining spin Chern insulating materials.
If the spin valence spectrum is not gapped, the changes in the spin Chern
numbers occur whenever this spectrum is zero. Materials whose spin valence
spectrum are gapless will be denoted spin Weyl topological insulators and its
definition together with some of their properties will be presented in this
work. The classification of materials from the properties of the spin valence
operator provides a new characterization which complements the existing list of
topological invariants.Comment: 12 pages, 6 figure
On quasi-nodal spheres and the spin Hall effect: the case of YH3 and CaTe
Band inversion is a known feature in a wide range of topological insulators
characterized by a change of orbital type around a high-symmetry point close to
the Fermi level. In some cases of band inversion in topological insulators, the
existence of quasinodal spheres has been detected, and the change of orbital
type is shown to be concentrated along these spheres in momentum space. To
understand this phenomenon, we develop a local effective fourfold Hamiltonian
that models the band inversion and reproduces the quasinodal sphere. This model
shows that the signal of the spin Hall conductivity, as well as the change of
orbital type, are both localized on the quasinodal sphere, and moreover, that
these two indicators characterize the topological nature of the material. Using
K-theoretical methods, we show that the change of orbital type parametrized by
an odd clutching function is equivalent to the strong Fu-Kane-Mele invariant.
We corroborate these results with ab initio calculations for the materials YH3
and CaTe, where in both cases the signal of the spin Hall conductivity is
localized on the quasinodal spheres in momentum space. We conclude that a
nontrivial spin Hall conductivity localized on the points of change of orbital
type is a good indicator for topological insulation.Comment: 10 pages, 5 figure
Proliferation dynamics of germinative zone cells in the intact and excitotoxically lesioned postnatal rat brain
BACKGROUND: The forebrain subventricular zone (SVZ)-olfactory bulb pathway and hippocampal subgranular zone (SGZ) generate neurons into adulthood in the mammalian brain. Neurogenesis increases after injury to the adult brain, but few studies examine the effect of injury on neural and glial precursors in the postnatal brain. To characterize the spatio-temporal dynamics of cell proliferation in the germinative zones, this study utilized a model of postnatal damage induced by NMDA injection in the right sensorimotor cortex at postnatal day 9. Dividing cell populations were labeled with 5-Bromodeoxyuridine (BrdU) in the intact and damaged postnatal brain. Identity of proliferating cells was determined by double immunolabeling with nestin, GFAP, NeuN and tomato lectin (TL). RESULTS: In the control brain, grouped BrdU+ cells were observed in the Rostral Migratory Stream (RMS), SVZ and SGZ. Maximal proliferation was seen at P12, persisted until P23 and diminished by P49. After injury, a striking reduction in the number of BrdU+ cells was observed in the ipsilateral SVZ from 10 hours (58% decrease) until 14 days post-lesion (88% decrease). In contrast, an increase in grouped BrdU+ cells was seen in the striatum adjacent to the depleted SVZ. Significantly reduced numbers of BrdU+ cells were also seen in the RMS until 3 days post-lesion. No changes were noted in the SGZ. Both in controls and lesioned hemispheres, BrdU+ cells located in the germinal zones were mostly nestin positive and negative for GFAP, NeuN, and TL. In the SVZ area lining the ventricle, BrdU+/nestin+ cells were mainly located between TL+ ependyma and parenchymal GFAP+ astrocytes. After excitotoxicity, a decrease in the number and orientation of GFAP/nestin+ prolongations leaving the SVZ to the cortex, corpus callosum and striatum was noted until 5 days post-lesion. CONCLUSION: Postnatal excitotoxic injury differentially affects proliferating cells in the germinative zones: no change is observed in the dentate gyrus whereas excitotoxicity causes a significant decrease in proliferating cells in the SVZ and RMS. Depletion of BrdU+ cells in the postnatal SVZ and RMS differs from previous studies after adult brain injury and may affect the SVZ-RMS migration and is suggestive of progenitor recruitment to injured areas
Calidad de lana Merino de esquila preparto: Una aproximación a su variabilidad en la provincia de Río Negro
La cría de ovinos Merino para lana y carne es la principal actividad ganadera en las regiones áridas y semiáridas de la provincia de Río Negro. La producción de lana Merino es uno de los principales productos de esta actividad y una fuente relevante de ingresos económicos de las poblaciones del interior de la provincia. Esta actividad se realiza en diversas condiciones ambientales, y en sistemas productivos extensivos que son fuertemente afectados por las fluctuaciones ambientales debido a una dependencia casi exclusiva sobre la oferta forrajera de los pastizales naturales, y un bajo nivel de infraestructura y uso de insumos para afrontar las variaciones climáticas. A pesar de esta realidad productiva se desconoce la variabilidad de la calidad de lana a escala regional. El objetivo general de esta tesis fue estudiar la variabilidad en la calidad de lana en la provincia de Río Negro y su dinámica en el tiempo. Para ello, se analizaron muestras de lana comercial representativas de la producción anual del (período 2014-2015) de 68 establecimientos, y registros de análisis comerciales de 113 establecimientos (periodo 2002-2015) realizados por el Laboratorio de Fibras Textiles INTA Bariloche de lana Merino de esquila preparto mediante técnicas de estadística multivariada. Los resultados sugieren la existencia de un gradiente de variación en la calidad de lana Merino de esquila preparto con orientación Oeste-Este en el área de estudio. Esta variabilidad reflejaría posibles asociaciones entre algunos parámetros de calidad de lana y la heterogeneidad del ambiente, expresándose mayormente en los establecimientos ubicados en los extremos longitudinales del área de estudio. Por otro lado, la calidad de lana reflejo una sensibilidad frente a las perturbaciones ambientales ocurridas durante el periodo estudiado, registrando también una capacidad de recuperación luego de estos impactos. Esta tesis aporta nuevos desafíos en la búsqueda por entender la variabilidad en la calidad de lanas a escala regional, y remarca la necesidad de avanzar en una mayor comprensión de la influencia ambiental sobre parámetros de calidad de lana.The breeding of Merino sheep for wool and meat is the main livestock activity in the arid and semi-arid regions of the province of Río Negro. The production of Merino wool is one of the main products of this activity and a relevant source of economic income of the populations of the interior of the province. This activity is carried out in diverse environmental conditions, and in extensive productive systems that are strongly affected by environmental fluctuations
due to an almost exclusive dependence on the forage supply of natural pastures, and a low level of infrastructure and use of inputs to face the climatic variations. In spite of this productive reality, the variability of wool production and quality at provincial regional scale is unknown. The general objective of this thesis was to study the variability in wool quality in the province of Río Negro and its dynamics over time. We used wool samples of Merino sheep representative of the annual production of (period 2014-2015) of 68 farms, and data from commercial analysis records of 113 farms (period 2002-2015) processed by the Laboratorio de Fibras Textiles from the Instituto Nacional de Tecnología Agropecuaria
(INTA) Bariloche. This data set was analysed with multivariate techniques (Cluster and Principal Components). We found a gradient of variation in wool quality with West-East orientation in the study area. This variability would reflect possible associations between some parameters of wool quality and the heterogeneity of the environment. We record that the wool quality was sensitivity to environmental disturbances that occurred during the
period studied, and also a capacity for recovery after these impacts. The results of this thesis encourage the need to advance in a greater understanding of the environmental influence on wool quality. This thesis is a first approach to understand and describe the regional variation of wool quality during an extensive period of study and in a wide area of the province of Rio Negro. The information generated contributes to the design and implementation of public policies and differential technological developments, considering
the variability of the environment and production.Estación Experimental Agropecuaria BarilocheFil: Gonzalez, Ezequiel Bernardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Área Producción Animal. Laboratorio de Fibras Textiles de Origen Animal; Argentin
Sistema de costos por lote de aves, para determinar los resultados económicos de la empresa Avikonor S. A. C. en el año 2019
El presente trabajo tiene como objetivo general describir la implementación del sistema de costos por lotes de aves en ciclo de producción, esto ante la necesidad de la empresa AVIKONOR S.A.C. para determinar los resultados económicos durante la etapa de postura de cada lote de gallinas y tomar la decisión de realizar la venta en el momento más adecuado, de manera que no afecte a la rentabilidad de la empresa.
El aporte como asesor contable fue diseñar, desarrollar e implementar un sistema de costos por lotes de aves en el periodo de producción, utilizando como herramienta un software que permite registrar y acumular la información de costos y de esta manera tener el análisis de rentabilidad de cada lote durante la etapa de postura.
El sistema de costeo utilizado fue el Costeo Directo, el cual identifica las operaciones que valúan el inventario de alimento, la mano de obra y los gastos de fabricación que varían en relación al volumen de huevos producidos por cada lote. En este sistema los costos y gastos son los que directamente se incurren en cada lote, eliminando aquellos que no tienen relación directa con el manejo de las gallinas por considerarlas como gastos administrativos del periodo
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