Stable propagation of pulsed beams in Kerr focusing media with modulated dispersion

We propose the modulation of dispersion to prevent collapse of planar pulsed beams which propagate in Kerr-type self-focusing optical media. As a result, we find a new type of two-dimensional spatio-temporal solitons stabilized by dispersion management. We have studied the existence and properties of these solitary waves both analytically and numerically. We show that the adequate choice of the modulation parameters optimizes the stabilization of the pulse.Comment: 3 pages, 3 figures, submitted to Optics Letter

Mineralogical Characterization and Ceramic Aplication of Muds From Washing of Natural Detritic Deposits

Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasFALSEpu

Controllable soliton emission from a Bose-Einstein condensate

We demonstrate, through numerical simulations, the controllable emission of matter-wave bursts from a Bose-Einstein Condensate in a shallow optical dipole trap. The process is triggered by spatial variations of the scattering length along the trapping axis. In our approach, the outcoupling mechanism are atom-atom interactions and thus, the trap remains unaltered. Once emitted, the matter wave forms a robust soliton. We calculate analytically the parameters for the experimental implementation of this atomic soliton machine gun.Comment: 4 pages, 5 figure

Determination of the pole position of the lightest hybrid meson candidate

Mapping states with explicit gluonic degrees of freedom in the light sector is a challenge, and has led to controversies in the past. In particular, the experiments have reported two different hybrid candidates with spin-exotic signature, pi1(1400) and pi1(1600), which couple separately to eta pi and eta' pi. This picture is not compatible with recent Lattice QCD estimates for hybrid states, nor with most phenomenological models. We consider the recent partial wave analysis of the eta(') pi system by the COMPASS collaboration. We fit the extracted intensities and phases with a coupled-channel amplitude that enforces the unitarity and analyticity of the S-matrix. We provide a robust extraction of a single exotic pi1 resonant pole, with mass and width 1564 +- 24 +- 86 MeV and 492 +- 54 +- 102 MeV, which couples to both eta(') pi channels. We find no evidence for a second exotic state. We also provide the resonance parameters of the a2(1320) and a2'(1700).Comment: 6 pages + 3 pages of supplemental material. Version to appear on Phys.Rev.Let

A Deep Learning based Generalized Ground Motion Model for the Chilean Subduction Seismic Environment

This paper proposes a deep learning-based generalized ground motion model (GGMM) for interface and inslab subduction earthquakes recorded in Chile. A total of ~7000 ground-motion records from ~1700 events are used to train the GGMM. Unlike common ground-motion models (GMM), which generally consider individual ground-motion intensity measures such as spectral acceleration at a given period, the proposed GGMM is a data-driven framework that coherently uses recurrent neural networks (RNN) and hierarchical mixed-effects regression to output a cross-dependent vector of 35 ground-motion intensity measures (IM). The IM vector includes geomean of Arias intensity, peak ground velocity, peak ground acceleration, and significant duration, and RotD50 spectral accelerations at 32 periods between 0.05 to 5 seconds (denoted as Sa(T)). The inputs to the GMM include six causal seismic source and site parameters. The statistical evaluation of the proposed GGMM shows that the proposed framework results in high prediction power with coefficient of determination R2 > 0.7 for most IMs while maintaining the cross-IM dependencies. Furthermore, it is observed that the proposed GGMM leads to better goodness of fit for all periods of Sa(T) compared to two state-of-the-art Chilean GMMs (on average 0.2 higher R2)

Migration of Rural China: The Consequences of the New Economic System

During 30 years, China has stand out over other countries due to the accelerated growth process that it has been presenting, also for having an emergent economy with the highest foreign investment indicators which allow the country to count with a dynamic international trade. But all this success is not for free; to accomplish a rapid growth, this country had to take some special measures like the creation of technological and economic development zones, industrial parks, between others that permit China to be an attractive country for foreigners. But even though the country is achieving its main economical objective; the situation China is living today in the interior of the coun¬try, makes all the economical efforts worthless. The majority of income resulting from direct foreign investment and trade is only staying in the hands of few people and the gaps between urban and rural zones are getting bigger by the day, situa¬tion that impulses migration at a scandalous growing rates. There is also a lack of work regulations which result in multinationals augmenting their greed of earning more money by reducing costs at the expense of scarifying their employees´ right of counting with a safe and healthy work environment

Analysis of human physical vulnerability using static equilibrium techniques of a Hazard flood for the determination of unsafe areas in the city of Catacaos - Piura, Peru

Heavy rains and El Nio phenomenon are recurring natural phenomena at a national level. These can cause floods due to the overflowing of rivers, which, when close to cities, can cause both human and material losses. The district of Catacaos, located in the city of Piura, was the one with the highest number of injuries due to the flood caused by El Nio phenomenon in 2017. This phenomenon causes a large amounts of rainfalls due to the presence of abnormally warm waters along the northern coast of Peru [1]. It is for this reason that the need arose to carry out an analysis of the physical vulnerability due to instability of people through static equilibrium, in said district, in order to present maps of unsafe areas in the face of this phenomenon. In this investigation, flood hazard maps are generated simulating the one presented in 2017, using 2D hydraulic modeling. For the generation of vulnerability curves, the instability analysis is performed by moment and drag force. Finally, maps with unsafe areas are made using ArcGis software. Where the results obtained indicate that 29.37% of the city was flooded. Likewise, the vulnerability maps generated show us that women and men over 18 years of age in the city of Catacaos would be vulnerable to dragging and overturning in the face of floods in 16.54% and 13.21%, respectively, of the total studied area. This information will be useful for the development of future evacuation plans during floods, carried out by national entities. © Published under licence by IOP Publishing Ltd

A recurrent-neural-network-based generalized ground-motion model for the Chilean subduction seismic environment

This paper proposes a deep learning-based generalized ground motion model (GGMM) for interface and intraslab subduction earthquakes recorded in Chile. A total of ∼7000 ground-motion records from ∼1700 events are used to train the proposed GGMM. Unlike common ground-motion models (GMMs), which generally consider individual ground-motion intensity measures such as peak ground acceleration and spectral accelerations at given structural periods, the proposed GGMM is based on a data-driven framework that coherently uses recurrent neural networks (RNNs) and hierarchical mixed-effects regression to output a cross-dependent vector of 35 ground-motion intensity measures (denoted as IM). The IM vector includes geometric mean of Arias intensity, peak ground velocity, peak ground acceleration, and significant duration (denoted as Iageom, PGVgeom, PGAgeom, and D5-95geom, respectively), and RotD50 spectral accelerations at 31 periods between 0.05 and 5 s for a 5 % damped oscillator (denoted as Sa(T)). The inputs to the GGMM include six causal seismic source and site parameters, including fault slab mechanism, moment magnitude, closest rupture distance, Joyne-Boore distance, soil shear-wave velocity, and hypocentral depth. The statistical evaluation of the proposed GGMM shows high prediction power with R2 > 0.7 for most IMs while maintaining the cross-IM dependencies. Furthermore, the GGMM is carefully compared against two state-of-the-art Chilean GMMs, showing that the proposed GGMM leads to better goodness of fit for all periods of Sa(T) compared to the two considered GMMs (on average 0.2 higher R2). Finally, the GGMM is implemented to select hazard-consistent ground motions for nonlinear time history analysis of a sophisticated finite-element model of a 20-story steel special moment-resisting frame. Results of this analysis are statistically compared against those for hazard-consistent ground motions selected based on the conditional mean spectrum (CMS) approach. In general, it is observed that the drift demands computed using the two approaches cannot be considered statistically similar and the GGMM leads to higher demands

Actividad hidrolítica de aislados bacterianos con potencial aplicación en el tratamiento de efluentes de frigorífico

Los efluentes de la industria frigorífica se caracterizan por presentar altas concentraciones de proteínas, grasas y polisacáridos. La degradación de estos compuestos a sus constituyentes monoméricos es realizada por la acción de enzimas extracelulares, producidas y secretadas por bacterias hidrolíticas (BH). En consecuencia, la actividad de estos microorganismos favorece el aumento de las tasas de degradación de la fracción orgánica presente en este tipo de residuos. En el presente estudio, un total de 15 bacterias productoras de enzimas extracelulares fueron aisladas y seleccionadas al presentar un índice de actividad enzimática ? 2,0. De estos 15 aislados, 7 presentaron actividad proteolítica (46,6%), 3 amilolítica (20%), 3 celulolítica (20%) y 2 lipolítica (13,4%). Adicionalmente, fue evidenciado efecto antagónico entre algunos de los aislados seleccionados, indicando su posible desventaja competitiva en condiciones naturales. Se concluye que las BH obtenidas evidencian un potencial promisorio para la optimización de sistemas de tratamiento de aguas residuales procedentes de la industria frigorífica

On the value of early marine weather observations: The Malaspina expedition (1789–94)

Great advances in meteorological science were made in the late eighteenth century. In particular, meteorological instruments were carried on ships and the first systematic meteorological readings over the oceans were made. One of these collections of instrumental meteorological readings was carried out by the Malaspina expedition (1789–94), organized by the Spanish Crown to study its vast possessions around the world. We have recovered meteorological variables such as air temperature (maximum and minimum), atmospheric pressure (maximum and minimum), wind (intensity and direction), and appearance (state of the sky) from the documentation generated by the explorers during the journey. In total, nearly 13, 000 instrumental data have been digitized and rescued from this maritime expedition. The comparison of daily temperature and pressure observations with reanalysis and weather stations data shows a good overall agreement. Moreover, apparent discrepancies during several anchored periods have allowed for testing the consistency and quality of these early instrumental marine weather readings