FRW and domain walls in higher spin gravity

We present exact solutions to Vasiliev's bosonic higher spin gravity equations in four dimensions with positive and negative cosmological constant that admit an interpretation in terms of domain walls, quasi-instantons and Friedman-Robertson-Walker (FRW) backgrounds. Their isometry algebras are infinite dimensional higher-spin extensions of spacetime isometries generated by six Killing vectors. The solutions presented are obtained by using a method of holomorphic factorization in noncommutative twistor space and gauge functions. In interpreting the solutions in terms of Fronsdal-type fields in spacetime, a field-dependent higher spin transformation is required, which is implemented at leading order. To this order, the scalar field solves Klein-Gordon equation with conformal mass in (anti) de Sitter space. We interpret the FRW solution with de Sitter asymptotics in the context of inflationary cosmology and we expect that the domain wall and FRW solutions are associated with spontaneously broken scaling symmetries in their holographic description. We observe that the factorization method provides a convenient framework for setting up a perturbation theory around the exact solutions, and we propose that the nonlinear completion of particle excitations over FRW and domain wall solutions requires black hole-like states.Comment: 63 page

Non-Gaussianities due to Relativistic Corrections to the Observed Galaxy Bispectrum

High-precision constraints on primordial non-Gaussianity (PNG) will significantly improve our understanding of the physics of the early universe. Among all the subtleties in using large scale structure observables to constrain PNG, accounting for relativistic corrections to the clustering statistics is particularly important for the upcoming galaxy surveys covering progressively larger fraction of the sky. We focus on relativistic projection effects due to the fact that we observe the galaxies through the light that reaches the telescope on perturbed geodesics. These projection effects can give rise to an effective $f_{\rm NL}$ that can be misinterpreted as the primordial non-Gaussianity signal and hence is a systematic to be carefully computed and accounted for in modelling of the bispectrum. We develop the technique to properly account for relativistic effects in terms of purely observable quantities, namely angles and redshifts. We give some examples by applying this approach to a subset of the contributions to the tree-level bispectrum of the observed galaxy number counts calculated within perturbation theory and estimate the corresponding non-Gaussianity parameter, $f_{\rm NL}$, for the local, equilateral and orthogonal shapes. For the local shape, we also compute the local non-Gaussianity resulting from terms obtained using the consistency relation for observed number counts. Our goal here is not to give a precise estimate of $f_{\rm NL}$ for each shape but rather we aim to provide a scheme to compute the non-Gaussian contamination due to relativistic projection effects. For the terms considered in this work, we obtain contamination of $f_{\rm NL}^{\rm loc} \sim {\mathcal O}(1)$.Comment: 31 pages, 6 figures, Typos corrected to match the published version in JCA

Cultivo del brócoli, alternativa de producción hortícola en el oriente antioqueño.

Se refiere al cultivo del brócoli, Brassica oleracea como alternativa de producción para el oriente antioqueño de Colombia, indicando el valor nutritivo de la hortaliza, los requerimientos de clima, suelo y semillas, las distancias de siembra, variedades e híbridos aconsejados y las prácticas de fertilización, desyerba y riego. Se mencionan algunas plagas y enfermedades presentes en la región como Peronospora parasítica, Xanthomonas campestris, Alternaria sp. y la polilla del repollo, Plutella xylostella. Se dan instrucciones sobre cosecha y empaque del producto y su utilizaciónBrócoli-Brassica oleracea var. italic

Producción comercial de hortalizas en el centro de investigación "La Selva": un a estrategia de investigación, validación y transferencia de tecnología

Con este trabajo se busca ofrecer nuevas alternativas a los horticultores, teniendo un permanente contacto con toda la cadena de producción y fue así como se incursionó en nuevos esquemas de transporte, empaque y valor agregado. Se orientaron trabajos de poscosecha que permitieron un mejor aprovechamiento de los productos de segunda

Evaluating the performance of spectral indexes for identify high Andean wetlands

[EN] High Andean wetlands are habitats critical to life forms that have adapted to these extreme high mountain ecosystems, and for living beings that inhabit the lower parts of the basin; they are spaces that contain high diversity of flora and fauna characteristic of these places and are strongly associated with the water component. There lies the importance of identifying and monitoring ecosystems, using easy applicable methods and allowing results every two weeks approximately, they are inexpensive and highly reliable. Methods of monitoring in short periods, they are economically profitable and provide reliable information, they correspond to the evaluations by satellite images, specifically applying the methods of spectral indices. Thereby, the objective of the research was to evaluate the performance of six indices, considered to be the most used to identify high Andean wetlands (humidity index at surface level, normalized difference water index, normalized difference vegetation index, enhanced vegetation index, index of vegetation to the surface and tasseled CAP vegetation), in periods of low precipitation, using imagery Landsat 8 OLI. Comparing the performance of those indexes in the identification of wetlands through cross-validation and bootstrap statistical learning, the index that showed better performance was tasseled CAP vegetation, revealing the lowest value of the average of the mean square error of iterations between the test failure rate and training. The index tasseled CAP vegetation, shows greater reliability to identify and evaluate high Andean wetlands.[ES] Los humedales altoandinos son hábitats fundamentales para las formas de vida que se han adaptado a estos ecosistemas extremos de alta montaña, y para los seres vivos que habitan en las partes bajas de la cuenca; son espacios que albergan alta diversidad de flora y fauna propias de estos lugares y están fuertemente asociados con el componente hídrico. De allí radica la importancia de identificar y monitorear, utilizando métodos fácilmente aplicables y que permitan obtener resultados cada dos semanas aproximadamente, que sean poco costosos y altamente confiables. Los métodos de monitoreo en periodos cortos, económicamente rentables y proveen información confiable, corresponden a las evaluaciones mediante imágenes satelitales, específicamente aplicando los métodos de índices espectrales. De tal modo, el objetivo de la investigación fue evaluar el desempeño de seis índices, considerados como los más utilizados para identificar humedales altoandinos (índice de humedad a nivel de superficie, índice de diferencia normalizada de agua, índice de vegetación de diferencia normalizada, índice de vegetación mejorada, índice de vegetación ajustada a la superficie y tasseled CAP vegetación), en periodos de escasa precipitación, utilizando imágenes Landsat 8 OLI. Comparando el desempeño de los referidos índices en la identificación de humedales mediante el aprendizaje estadístico de validación cruzada y bootstrap, el índice que mostró mejor desempeño fue tasseled CAP vegetación, revelando el valor más bajo del promedio de error medio cuadrático de las iteraciones entre la tasa de error de prueba y el entrenamiento. El índice tasseled CAP vegetación, muestra mayor confiabilidad para identificar y evaluar humedales altoandinos.Aponte-Saravia, J.; Ospina-Noreña, JE. (2019). Evaluando el desempeño de índices espectrales para identificar humedales alto andinos. Revista de Teledetección. (53):59-72. https://doi.org/10.4995/raet.2019.10580SWORD59725

Situación patológica de las hortalizas cultivadas en el oriente antioqueño.

Se indican los principales problemas fitopatológicos de las hortalizas en el Oriente Antioqueño, con énfasis en los cultivos de tomate, zanahoria, repollo, pimentón, remolacha, lechuga, cebolla de rama y coliflor. En relación con el tomate se mencionan los hongos Phytophthora infestans, Phoma andina, Xanthomonas campestris, Pseudomonas solanacearum, Alternaria solani y Botrytis cinerea principalmente. La zanahoria es atacada por los siguientes patógenos: Cercospora carotae, Alternaria dauci, el nematodo Meloidogyne spp. y por los hongos Rosellinia, Sclerotium rolfsii y Pythium. En el repollo se presenta ataque de Xanthomonas campestris, Mycosphaerela brassicola y Alternaria brassicae. En pimentón Alternaria solani, Cercospora capsci y Brotrytis cinerea. En las demás hortalizas prevalecen los hongos Cercospora beticola en remolacha, Sclerotinia sclerotiorum en lechuga y Alternaria porri y Peronospara destructor en ceboll

Khronon inflation

We study the possibility that the approximate time shift symmetry during inflation is promoted to the full invariance under time reparametrization t \to \tilde t(t), or equivalently under field redefinition of the inflaton \phi \to \tilde\phi(\phi). The symmetry allows only two operators at leading order in derivatives, so that all n-point functions of scalar perturbations are fixed in terms of the power spectrum normalization and the speed of sound. During inflation the decaying mode only decays as 1/a and this opens up the possibility to violate some of the consistency relations in the squeezed limit, although this violation is suppressed by the (small) breaking of the field reparametrization symmetry. In particular one can get terms in the 3-point function that are only suppressed by 1/k_L in the squeezed limit k_L \to 0 compared to the local shape.Comment: 15 pages, 1 figure, v2. changes regarding the violation of the consistency relation. JCAP published versio

Conformal consistency relations for single-field inflation

We generalize the single-field consistency relations to capture not only the leading term in the squeezed limit---going as 1/q^3, where q is the small wavevector---but also the subleading one, going as 1/q^2. This term, for an (n+1)-point function, is fixed in terms of the variation of the n-point function under a special conformal transformation; this parallels the fact that the 1/q^3 term is related with the scale dependence of the n-point function. For the squeezed limit of the 3-point function, this conformal consistency relation implies that there are no terms going as 1/q^2. We verify that the squeezed limit of the 4-point function is related to the conformal variation of the 3-point function both in the case of canonical slow-roll inflation and in models with reduced speed of sound. In the second case the conformal consistency conditions capture, at the level of observables, the relation among operators induced by the non-linear realization of Lorentz invariance in the Lagrangian. These results mean that, in any single-field model, primordial correlation functions of \zeta are endowed with an SO(4,1) symmetry, with dilations and special conformal transformations non-linearly realized by \zeta. We also verify the conformal consistency relations for any n-point function in models with a modulation of the inflaton potential, where the scale dependence is not negligible. Finally, we generalize (some of) the consistency relations involving tensors and soft internal momenta.Comment: 26 pages, 1 figure. v2. Corrected typos, notably a sign error in eq. (54). Matches JCAP published versio

The Efficacy of Auditory Perceptual Training for Tinnitus: A Systematic Review

Auditory perceptual training affects neural plasticity and so represents a potential strategy for tinnitus management. We assessed the effects of auditory perceptual training on tinnitus perception and/or its intrusiveness via a systematic review of published literature. An electronic database search using the keywords ‘tinnitus and learning’ or ‘tinnitus and training’ was conducted, updated by a hand search. The ten studies identified were reviewed independently by two reviewers, data were extracted, study quality was assessed according to a number of specific criteria and the information was synthesised using a narrative approach. Nine out of the ten studies reported some significant change in either self-reported or psychoacoustic outcome measures after auditory training. However, all studies were quality rated as providing low or moderate levels of evidence for an effect. We identify a need for appropriately randomised and controlled studies that will generate high-quality unbiased and generalisable evidence to ascertain whether or not auditory perceptual training has a clinically relevant effect on tinnitus

The Effective Theory of Quintessence: the w<-1 Side Unveiled

We study generic single-field dark energy models, by a parametrization of the most general theory of their perturbations around a given background, including higher derivative terms. In appropriate limits this approach reproduces standard quintessence, k-essence and ghost condensation. We find no general pathology associated to an equation of state w_Q < -1 or in crossing the phantom divide w_Q = -1. Stability requires that the w_Q < -1 side of dark energy behaves, on cosmological scales, as a k-essence fluid with a virtually zero speed of sound. This implies that one should set the speed of sound to zero when comparing with data models with w_Q < -1 or crossing the phantom divide. We summarize the theoretical and stability constraints on the quintessential plane (1+w_Q) vs. speed of sound squared.Comment: 35 pages, 5 figures, v3: minor modifications, JCAP published versio