2,818 research outputs found

    Conformal Field Theory as Microscopic Dynamics of Incompressible Euler and Navier-Stokes Equations

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    We consider the hydrodynamics of relativistic conformal field theories at finite temperature. We show that the limit of slow motions of the ideal hydrodynamics leads to the non-relativistic incompressible Euler equation. For viscous hydrodynamics we show that the limit of slow motions leads to the non-relativistic incompressible Navier-Stokes equation. We explain the physical reasons for the reduction and discuss the implications. We propose that conformal field theories provide a fundamental microscopic viewpoint of the equations and the dynamics governed by them.Comment: 4 page

    Partition functions of chiral gauge theories on the two dimensional torus and their duality properties

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    Two different families of abelian chiral gauge theories on the torus are investigated: the aim is to test the consistency of two-dimensional anomalous gauge theories in the presence of global degrees of freedom for the gauge field. An explicit computation of the partition functions shows that unitarity is recovered in particular regions of parameter space and that the effective dynamics is described in terms of fermionic interacting models. For the first family, this connection with fermionic models uncovers an exact duality which is conjectured to hold in the nonabelian case as well.Comment: RevTex, 13 pages, references adde

    Gut inflammatory diseases, infection, and nutrition

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    Factors associated with relationship dissolution of Australian families with children

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    This project investigated the context in which relationship instability occurs by examining the factors (at the individual, and the couple/family levels) that precede relationship dissolution within Australian families with children. The report considers whether mental health problems, impaired physical functioning, hazardous levels of alcohol consumption and smoking are associated with later divorce or separation

    Dise?o e implementaci?n del mundo caim?n del videojuego jaguares, que da a conocer la morfolog?a, uso y significado de la cer?mica de los ancestros del Tolima.

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    98 p. Recurso Electr?nicoDurante d?cadas, el Museo Antropol?gico de la Universidad del Tolima y el grupo GRAPA (Grupo de Investigaci?n en Arqueolog?a y Patrimonio Regional) han realizado investigaciones arqueol?gicas a lo largo del territorio tolimense, logrando hallazgos f?siles de animales y vegetales, adem?s de elementos cer?micos que datan desde 10.000 a.C. hasta la conquista y colonia espa?ola. Sin embargo, las nuevas generaciones se muestran indiferentes ante los conocimientos obtenidos. Este proyecto busca crear un videojuego para ense?ar de manera novedosa, a ni?os con edades entre ocho a catorce a?os sobre las cer?micas tolimenses. Se implementa sobre Unity v5.5.1f1, aplicando la metodolog?a de desarrollo ?gil SUM que se adapta para la creaci?n de videojuegos utilizando roles de SCRUM, e incorpora seis fases consecutivas que son: concepto, planificaci?n, elaboraci?n, beta, cierre y gesti?n de riesgos que se realiza de manera continua durante la ejecuci?n del desarrollo. Durante la fase de concepto se realiza una investigaci?n amplia sobre la cer?mica tolimense, que posteriormente sirve como insumo para crear una propuesta detallada y s?lida en la etapa de planificaci?n. En la fase de elaboraci?n se aplica la metodolog?a de Arquitectura Dirigida por Modelos (MDA) orientada a la elaboraci?n de videojuegos. Esta fase se realiza de manera iterativa y en conjunto con las pruebas Beta que permiten evaluar el cumplimiento de los objetivos planteados a medida que se avanza en el desarrollo. Por ?ltimo en la fase de cierre se generan los productos finales y se eval?an las lecciones aprendidas. Palabras claves: Unity, Videojuego 2D, Videojuego Educativo, Metodolog?a SUM, Museo Antropol?gico, Cer?mica tolimense.For decades, the Anthropological Museum of the University of Tolima and the group GRAPA (Research Group in Archeology and Regional Heritage) have carried out archaeological research throughout the territory of Tolima, finding fossil of animals and plants, as well as ceramic elements dating back to from 10,000 BC until the Spanish conquest and colony. However, the new generations are indifferent to the knowledge obtained. This project seeks to create a video game to teach in a novel way, to children aged between eight and fourteen years old, about the ceramics of Tolima. It is implemented on Unity v5.5.1f1, applying the agile development methodology SUM that is adapted for the creation of video games using SCRUM roles, and incorporates six consecutive phases that are: concept, planning, preparation, beta, closure and risk management that is done continuously during the execution of the development. During the concept phase, a comprehensive investigation is carried out on ceramic of Tolima, which later serves as an input to create a detailed and solid proposal in the planning stage. In the elaboration phase, the methodology of Model-Directed Architecture (MDA), oriented to the elaboration of videogames is applied. This phase is carried out iteratively and in conjunction with Beta tests that allow evaluating compliance with the objectives set as progress is made in development. Finally, in the closing phase, the final products are generated and the lessons learned are evaluated. Keywords: Unity, 2D Videogame, Educational Videogame, SUM Methodology, Anthropological Museum, Tolima?s Ceramics

    Chemical composition and toxic activity of essential oil of Caryopteris incana against Sitophilus zeamais

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    During our screening program for new agrochemicals from Chinese medicinal herbs, essential oil of Caryopteris incana aerial parts was found to possess strong insecticidal activities against the maize weevil, Sitophilus zeamais. A total of 37 components of the essential oil were identified by GC and GC/MS. Estragole (24.8%) and linalool (14.0%) are the two main components of the essential oil followed by 1,8-cineol (5.2%) and δ-guaiene (4.1%). The essential oil possesses strong fumigant toxicity against S. zeamais adults with an LC50 value of 10.05 mg/L air. The essential oil of C. incana also showed contact toxicity against S. zeamais adults with an LD50 value of 122.65 μg/adult. The essential oil C. incana may have potential to be developed as a new natural fumigant/insecticide for the control of stored product insects.Key words: Caryopteris incana, Sitophilus zeamais, fumigant, contact toxicity, essential oil composition, estragole, linalool

    Toward Generic Models for Green LAI Estimation in Maize and Soybean: Satellite Observations

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    Informative spectral bands for green leaf area index (LAI) estimation in two crops were identified and generic models for soybean and maize were developed and validated using spectral data taken at close range. The objective of this paper was to test developed models using Aqua and Terra MODIS, Landsat TM and ETM+, ENVISAT MERIS surface reflectance products, and simulated data of the recently-launched Sentinel 2 MSI and Sentinel 3 OLCI. Special emphasis was placed on testing generic models which require no re-parameterization for these species. Four techniques were investigated: support vector machines (SVM), neural network (NN), multiple linear regression (MLR), and vegetation indices (VI). For each technique two types of models were tested based on (a) reflectance data, taken at close range and resampled to simulate spectral bands of satellite sensors; and (b) surface reflectance satellite products. Both types of models were validated using MODIS, TM/ETM+, and MERIS data. MERIS was used as a prototype of OLCI Sentinel-3 data which allowed for assessment of the anticipated accuracy of OLCI. All models tested provided a robust and consistent selection of spectral bands related to green LAI in crops representing a wide range of biochemical and structural traits. The MERIS observations had the lowest errors (around 11%) compared to the remaining satellites with observational data. Sentinel 2 MSI and OLCI Sentinel 3 estimates, based on simulated data, had errors below 8%. However the accuracy of these models with actual MSI and OLCI surface reflectance products remains to be determined

    The orientation and kinematics of inner tidal tails around dwarf galaxies orbiting the Milky Way

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    Using high-resolution collisionless N-body simulations we study the properties of tidal tails formed in the immediate vicinity of a two-component dwarf galaxy evolving in a static potential of the Milky Way (MW). The stellar component of the dwarf is initially in the form of a disk and the galaxy is placed on an eccentric orbit motivated by CDM-based cosmological simulations. We measure the orientation, density and velocity distribution of the stars in the tails. Due to the geometry of the orbit, in the vicinity of the dwarf, where the tails are densest and therefore most likely to be detectable, they are typically oriented towards the MW and not along the orbit. We report on an interesting phenomenon of `tidal tail flipping': on the way from the pericentre to the apocentre the old tails following the orbit are dissolved and new ones pointing towards the MW are formed over a short timescale. We also find a tight linear relation between the velocity of stars in the tidal tails and their distance from the dwarf. Using mock data sets we demonstrate that if dwarf spheroidal (dSph) galaxies in the vicinity of the MW are tidally affected their kinematic samples are very likely contaminated by tidally stripped stars which tend to artificially inflate the measured velocity dispersion. The effect is stronger for dwarfs on their way from the peri- to the apocentre due to the formation of new tidal tails after pericentre. Realistic mass estimates of dSph galaxies thus require removal of these stars from kinematic samples.Comment: 8 pages, 7 figures, accepted for publication in MNRA

    Interactions Between the Serotonergic and Other Neurotransmitter Systems in the Basal Ganglia: Role in Parkinson's Disease and Adverse Effects of L-DOPA

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    Parkinson's disease (PD) is characterized by the progressive loss of dopaminergic neurons in the substantia nigra. However, other non-dopaminergic neuronal systems such as the serotonergic system are also involved. Serotonergic dysfunction is associated with non-motor symptoms and complications, including anxiety, depression, dementia, and sleep disturbances. This pathology reduces patient quality of life. Interaction between the serotonergic and other neurotransmitters systems such as dopamine, noradrenaline, glutamate, and GABA controls the activity of striatal neurons and are particularly interesting for understanding the pathophysiology of PD. Moreover, serotonergic dysfunction also causes motor symptoms. Interestingly, serotonergic neurons play an important role in the effects of L-DOPA in advanced PD stages. Serotonergic terminals can convert L-DOPA to dopamine, which mediates dopamine release as a "false" transmitter. The lack of any autoregulatory feedback control in serotonergic neurons to regulate L-DOPA-derived dopamine release contributes to the appearance of L-DOPA-induced dyskinesia (LID). This mechanism may also be involved in the development of graft-induced dyskinesias (GID), possibly due to the inclusion of serotonin neurons in the grafted tissue. Consistent with this, the administration of serotonergic agonists suppressed LID. In this review article, we summarize the interactions between the serotonergic and other systems. We also discuss the role of the serotonergic system in LID and if therapeutic approaches specifically targeting this system may constitute an effective strategy in PD

    Informative spectral bands for remote green LAI estimation in C3 and C4 crops

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    Green leaf area index (LAI) provides insight into the productivity, physiological and phenological status of vegetation. Measurement of spectral reflectance offers a fast and nondestructive estimation of green LAI. A number of methods have been used for the estimation of green LAI; however, the specific spectral bands employed varied widely among the methods and data used. Our objectives were (i) to find informative spectral bands retained in three types of methods, neural network (NN), partial least squares (PLS) regression and vegetation indices (VI), for estimating green LAI in maize (a C4 species) and soybean (a C3 species); (ii) to assess the accuracy of the algorithms estimating green LAI using a minimal number of bands for each crop and generic algorithms for the two crops combined. Hyperspectral reflectance and green LAI of irrigated and rainfed maize and soybean were taken during eight years of observations (altogether 24 field-years) in very different weather conditions. The bands retained in the best NN, PLS and VI methods were in close agreement. The validity of these bands was further confirmed via the uninformative variable elimination PLS technique. The red edge and the NIR bands were selected in all models and were found the most informative. Identifying informative spectral bands across all four techniques provided insight into spectral features of reflectance specific for each species as well as those that are common to species with different leaf structures, canopy architectures and photosynthetic pathways. The analyses allowed development of algorithms for estimating green LAI in soybean and maize with no re-parameterization. These findings lay a strong foundation for the development of generic algorithms which is crucial for remote sensing of vegetation biophysical parameters
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