Modular Invariance on the Torus and Abelian Chern-Simons Theory

The implementation of modular invariance on the torus as a phase space at the quantum level is discussed in a group-theoretical framework. Unlike the classical case, at the quantum level some restrictions on the parameters of the theory should be imposed to ensure modular invariance. Two cases must be considered, depending on the cohomology class of the symplectic form on the torus. If it is of integer cohomology class $n$, then full modular invariance is achieved at the quantum level only for those wave functions on the torus which are periodic if $n$ is even, or antiperiodic if $n$ is odd. If the symplectic form is of rational cohomology class $\frac{n}{r}$, a similar result holds --the wave functions must be either periodic or antiperiodic on a torus $r$ times larger in both direccions, depending on the parity of $nr$. Application of these results to the Abelian Chern-Simons is discussed.Comment: 24 pages, latex, no figures; title changed; last version published in JM

Higher-U(2,2)-spin fields and higher-dimensional W-gravities: quantum AdS space and radiation phenomena

A physical and geometrical interpretation of previously introduced tensor operator algebras of U(2,2) in terms of algebras of higher-conformal-spin quantum fields on the anti-de Sitter space AdS_5 is provided. These are higher-dimensional W-like algebras and constitute a potential gauge guide principle towards the formulation of induced conformal gravities (Wess-Zumino-Witten-like models) in realistic dimensions. Some remarks on quantum (Moyal) deformations are given and potentially tractable versions of noncommutative AdS spaces are also sketched. The role of conformal symmetry in the microscopic description of Unruh and Hawking's radiation effects is discussed.Comment: LaTeX, 30 pages, 2 figures, final version to appear in Class. and Quant. Gra

Structure Constants for New Infinite-Dimensional Lie Algebras of U(N+,N-) Tensor Operators and Applications

The structure constants for Moyal brackets of an infinite basis of functions on the algebraic manifolds M of pseudo-unitary groups U(N_+,N_-) are provided. They generalize the Virasoro and W_\infty algebras to higher dimensions. The connection with volume-preserving diffeomorphisms on M, higher generalized-spin and tensor operator algebras of U(N_+,N_-) is discussed. These centrally-extended, infinite-dimensional Lie-algebras provide also the arena for non-linear integrable field theories in higher dimensions, residual gauge symmetries of higher-extended objects in the light-cone gauge and C^*-algebras for tractable non-commutative versions of symmetric curved spaces.Comment: 8 pages, LaTeX, no figures; minor comments added; to appear in J. Phys A (Math. Gen.

Non-Canonical Perturbation Theory of Non-Linear Sigma Models

We explore the O(N)-invariant Non-Linear Sigma Model (NLSM) in a different perturbative regime from the usual relativistic-free-field one, by using non-canonical basic commutation relations adapted to the underlying O(N) symmetry of the system, which also account for the non-trivial (non-flat) geometry and topology of the target manifold.Comment: 11 pages, 1 figure, LaTe

Documentação fotográfica do desempenho silvicultural de espécies arbóreas na recuperação de áreas degradadas pela deposição de rejeitos finos da mineração de cobre.

O presente trabalho documenta fotograficamente o desempenho silvicultural de espécies arbóreas plantadas numa área degradada pela deposição de rejeitos finos da Mineração Caraíba situada no sertão baiano, em Jaguarari,BA. A primeira fase de seleção das espécies mais tolerantes às áreas de rejeito aconteceu no período de 1991 até 1995, sendo as espécies arbóreas/arbustivas testadas: algaroba (Prosopis juliflora), angico (Anadenanthera columbina),aroeira(Myracrod), entre outras

Sampling Theorem and Discrete Fourier Transform on the Riemann Sphere

Using coherent-state techniques, we prove a sampling theorem for Majorana's (holomorphic) functions on the Riemann sphere and we provide an exact reconstruction formula as a convolution product of $N$ samples and a given reconstruction kernel (a sinc-type function). We also discuss the effect of over- and under-sampling. Sample points are roots of unity, a fact which allows explicit inversion formulas for resolution and overlapping kernel operators through the theory of Circulant Matrices and Rectangular Fourier Matrices. The case of band-limited functions on the Riemann sphere, with spins up to $J$, is also considered. The connection with the standard Euler angle picture, in terms of spherical harmonics, is established through a discrete Bargmann transform.Comment: 26 latex pages. Final version published in J. Fourier Anal. App

English Intermediate-Task Training Improves Zero-Shot Cross-Lingual Transfer Too

Intermediate-task training---fine-tuning a pretrained model on an intermediate task before fine-tuning again on the target task---often improves model performance substantially on language understanding tasks in monolingual English settings. We investigate whether English intermediate-task training is still helpful on non-English target tasks. Using nine intermediate language-understanding tasks, we evaluate intermediate-task transfer in a zero-shot cross-lingual setting on the XTREME benchmark. We see large improvements from intermediate training on the BUCC and Tatoeba sentence retrieval tasks and moderate improvements on question-answering target tasks. MNLI, SQuAD and HellaSwag achieve the best overall results as intermediate tasks, while multi-task intermediate offers small additional improvements. Using our best intermediate-task models for each target task, we obtain a 5.4 point improvement over XLM-R Large on the XTREME benchmark, setting the state of the art as of June 2020. We also investigate continuing multilingual MLM during intermediate-task training and using machine-translated intermediate-task data, but neither consistently outperforms simply performing English intermediate-task training

DESARROLLO DE UN SOFTWARE PARA UN SISTEMA INTEGRADO DE MONITOREO Y CONTROL BOVINO MEDIANTE DISPOSITIVOS DE RASTREO Y TECNOLOGÍAS DE TELECOMUNICACIONES

According to the Cattle Census in Colombia, carried out by the Colombian Agricultural Institute- ICA (2021), the bovine population is distributed in 633,408 farms and totals 27,973,390 animals. Of the 633,408 properties in the country, Boyacá has 14.0% destined for cattle [1], a percentage that offers a great opportunity for the development of technologies that can impact on an improvement of its management and production, this is how the idea of ​​implementing an integrated bovine monitoring and control system arises through the articulation of software development, tracking devices and telecommunications technologies. The development consists of the creation of a mobile application-type software that managesbovine vaccination cycles, allowing information to be stored and processed, thus contributing to increasing the competitiveness of ranchers in the department of Boyacá by preventing diseases and improving immunity to the same In addition, the system allows the monitoring of cattle through GPS location devices, located in each cattle, which send the information using the GSM network, this gives the farmer the possibility of identifying conditions escape or theft of bovines. The methodology implemented for the development of the project is raised in the following stages: 1. Search and analysis of information, 2. Know the opinion of the livestock producers, 3. Design and development of the application. The software contributes to the farmer in the implementation of good farming practices by allowing the administration of the bovine inventory, management of vaccination, access to information on diseases, knowing the delimitation of the property and generating reports of each one of the bovines, allowing timely and pertinent decision-making in eventualities.Según Censo bovino en Colombia, realizado por Instituto Colombiano Agropecuario-ICA (2021), la población bovina está distribuida en 633.408 predios ytotaliza 27.973.390 animales. De los 633.408 predios en el país, Boyacá tieneel 14,0% destinado a bovinos [1], porcentaje que brinda una gran oportunidadpara el desarrollo de tecnologías que puedan impactar en una mejora de su gestión yproducción, es así como surge la idea de implementar un sistema integrado de monitoreoy control bovino mediante la articulación de un desarrollo de software, dispositivosde rastreo y tecnologías de telecomunicaciones.El desarrollo consiste en la creación de un software tipo aplicación móvil que gestionalos ciclos de vacunación de los bovinos, permitiendo almacenar y procesar la información,contribuyendo así al aumento de la competitividad de los ganaderos en el departamentode Boyacá mediante prevención de enfermedades y mejora de la inmunidada las mismas. Además, el sistema permite el monitoreo de los bovinos mediante dispositivoslocalización GPS, ubicados en cada bovino, los cuales envían la información utilizandola red GSM, esto brinda al ganadero la posibilidad de identificar condicionesde fuga o hurto de los bovinos.La metodología implementada para el desarrollo del proyecto está planteada en lassiguientes etapas: 1. Búsqueda y análisis de información, 2. Conocer la opinión de losproductores ganaderos, 3. Diseño y desarrollo de la aplicación.El software aporta al ganadero en la implementación de buenas prácticas ganaderasal permitir administrar el inventario bovino, gestionar la vacunación, acceder a informaciónsobre enfermedades, conocer la delimitación del predio y generar informes decada uno de los bovinos, permitiendo la toma de decisiones oportunas y pertinentesen las eventualidades