Reply to `A comment on `The Cauchy problem of f(R) gravity''

We reply to a comment by Capozziello and Vignolo about the Cauchy problem of Palatini f(R) gravity.Comment: 3 pages, late

Hydrological cycle over South and Southeast Asian river basins as simulated by PCMDI/CMIP3 experiments

We investigate how the climate models contributing to the PCMDI/CMIP3 dataset describe the hydrological cycle over four major South and Southeast Asian river basins (Indus, Ganges, Brahmaputra and Mekong) for the 20th, 21st (13 models) and 22nd (10 models) centuries. For the 20th century, some models do not seem to conserve water at the river basin scale up to a good degree of approximation. The simulated precipitation minus evaporation (P − E), total runoff (R) and precipitation (P) quantities are neither consistent with the observations nor among the models themselves. Most of the models underestimate P − E for all four river basins, which is mainly associated with the underestimation of precipitation. This is in agreement with the recent results on the biases of the representation of monsoonal dynamics by GCMs. Overall, a modest inter-model agreement is found only for the evaporation and inter-annual variability of P − E. For the 21st and 22nd centuries, models agree on the negative (positive) changes of P − E for the Indus basin (Ganges, Brahmaputra and Mekong basins). Most of the models foresee an increase in the inter-annual variability of P − E for the Ganges and Mekong basins, thus suggesting an increase in large low-frequency dry/wet events. Instead, no considerable future change in the inter-annual variability of P − E is found for the Indus and Brahmaputra basins

A Likelihood-Free Inference Framework for Population Genetic Data using Exchangeable Neural Networks

An explosion of high-throughput DNA sequencing in the past decade has led to a surge of interest in population-scale inference with whole-genome data. Recent work in population genetics has centered on designing inference methods for relatively simple model classes, and few scalable general-purpose inference techniques exist for more realistic, complex models. To achieve this, two inferential challenges need to be addressed: (1) population data are exchangeable, calling for methods that efficiently exploit the symmetries of the data, and (2) computing likelihoods is intractable as it requires integrating over a set of correlated, extremely high-dimensional latent variables. These challenges are traditionally tackled by likelihood-free methods that use scientific simulators to generate datasets and reduce them to hand-designed, permutation-invariant summary statistics, often leading to inaccurate inference. In this work, we develop an exchangeable neural network that performs summary statistic-free, likelihood-free inference. Our framework can be applied in a black-box fashion across a variety of simulation-based tasks, both within and outside biology. We demonstrate the power of our approach on the recombination hotspot testing problem, outperforming the state-of-the-art.Comment: 9 pages, 8 figure

Efecto de la defoliación post-quema sobre el crecimiento de dos gramíneas nativas en el Caldenal, Argentina

El crecimiento en los pastizales naturales semiáridos puede ser afectado por la longitud de tiempo que el pastoreo es excluido durante el período de regeneración post-fuego. El objetivo de este trabajo a campo fue estudiar el efecto de la defoliación post-fuego en diferentes estados fenológicos: vegetativo (defoliación temprana) y elongación de entrenudos (defoliación tardía) sobre el crecimiento de Piptochaetium napostaense y Poa ligularis, dos gramíneas nativas perennes muy importantes en la región semiárida templada central de Argentina (Caldenal). En general, los tratamientos de defoliación post-quema no afectaron el número de hojas verdes en las macollas de P. napostaense. La defoliación temprana después del tratamiento de fuego generalmente redujo el número de hojas verdes en las macollas de P. ligularis con respecto a las plantas control. Contrariamente, la defoliación tardía usualmente incrementó el número de hojas verdes en las macollas de P. ligularis. Sin embargo, en ambos casos, muy pocas de las diferencias detectadas fueron significativas (p0,05) a aquellas de las plantas no defoliadas. Inmediatamente después de los tratamientos de defoliación temprana y tardía, las tasas de crecimiento relativas de la altura y la longitud verde total de las macollas de las plantas de ambas especies fueron reducidas (p0.05) than values on non-defoliated plants, respectively. Immediately after early- and late-season defoliation treatments, relative growth rates for tiller height and total green length were reduced (p<0.05) on plants of both species with respect to control plants. Our results suggest that a one-year-period without severe defoliations after fire would be at least necessary for not risking the persistence of these perennial grasses in the Caldenal community.Fil: Pelaez, Daniel Valerio. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Boo, Roberto Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Mayor, M. D.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Elia, Omar Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Martinez, S. A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentin

Multipartite fully-nonlocal quantum states

We present a general method to characterize the quantum correlations obtained after local measurements on multipartite systems. Sufficient conditions for a quantum system to be fully-nonlocal according to a given partition, as well as being (genuinely) multipartite fully-nonlocal, are derived. These conditions allow us to identify all completely-connected graph states as multipartite fully-nonlocal quantum states. Moreover, we show that this feature can also be observed in mixed states: the tensor product of five copies of the Smolin state, a biseparable and bound entangled state, is multipartite fully-nonlocal.Comment: 5 pages, 1 figure. Version published in PRA. Note that it does not contain all the results from the previous version; these will be included in a later, more general, pape

On the local and non-local content of bipartite qubit and qutrit correlations

The local and non-local contents of non-local probability distributions are studied using the approach of Elitzur, Popescu and Rohrlich [Phys. Lett. A \textbf{162}, 25 (1992)]. This work focuses on distributions that can be obtained by single-copy von Neumann measurements on bipartite quantum systems. For pure two-qubit states Psi(theta)=cos(theta)|00>+sin(theta)|11>, with cos(theta)>=sin(theta), the local content of the corresponding probability distribution is found to lie between 1-sin(2*theta) and cos(2*theta). For the family Psi(gamma)= (|00>+|11>+gamma*|22>)/sqrt(2+gamma^2) of two-qutrit states, non-zero local content is found for gamma>2.Comment: Accepted version. Previous title "The Elitzur-Popescu-Rohrlich approach to quantum non-locality" changed for editorial reason

Euler Polynomials and Identities for Non-Commutative Operators

Three kinds of identities involving non-commutating operators and Euler and Bernoulli polynomials are studied. The first identity, as given by Bender and Bettencourt, expresses the nested commutator of the Hamiltonian and momentum operators as the commutator of the momentum and the shifted Euler polynomial of the Hamiltonian. The second one, due to J.-C. Pain, links the commutators and anti-commutators of the monomials of the position and momentum operators. The third appears in a work by Figuieira de Morisson and Fring in the context of non-Hermitian Hamiltonian systems. In each case, we provide several proofs and extensions of these identities that highlight the role of Euler and Bernoulli polynomials.Comment: 20 page

A viability criterion for modified gravity with an extra force

A recently proposed theory of modified gravity with an explicit ``anomalous'' coupling of the Ricci curvature to matter is discussed, and an inequality is derived which expresses a necessary and sufficient condition to avoid the notorius Dolgov-Kawasaki instability.Comment: 4 latex pages, to appear in Phys. Rev.