Frequency doubling of femtosecond pulses in walk-off compensated npp

Summary form only given. N-(4-nitrophenyl)-L-prolinol (NPP) is an organic molecular crystal developped by molecular engineering, that exhibits one of the highest phase-matchable second-order susceptibilities reported so far in the near-infrared spectral range (d/sub eff//spl ap/56 pm/V). However, the large spatial and temporal walk-off existing in NPP can limit severely the usefulness of the material away from the noncritical phase-matching (ncpm) wavelength and for shorter pulses. Here we show that subpicosecond pulses can be efficiently frequency-doubled and mixed in NPP with moderate pump intensities, by employing tilted pulse techniques. These techniques make use of the large Poynting vector walk-off exhibited by NPP crystals outside the ncpm. Such techniques are based on the diffraction of the input pump wave by a grating so that each spectral component is dispersed in a different direction, thus the resulting signal is a tilted pulse.Peer ReviewedPostprint (published version

Tailored particle current in an optical lattice by a weak time-symmetric harmonic potential

Quantum ratchets exhibit asymptotic currents when driven by a time-periodic potential of zero mean if the proper spatio-temporal symmetries are broken. There has been recent debate on whether directed currents may arise for potentials which do not break these symmetries. We show here that, in the presence of degeneracies in the quasienergy spectrum, long-lasting directed currents can be induced, even if the time reversal symmetry is not broken. Our model can be realized with ultracold atoms in optical lattices in the tight-binding regime, and we show that the time scale of the average current can be controlled by extremely weak fields.Comment: 4 pages, 4 figure

Intercalation and dynamics of hydrated Fe2+ in the vermiculites from Santa Olalla and Ojén

Although the intercalation of Fe3+ into layered phyllosicilicates-especially into smectites-attracted much attention in the past two decades, the information about Fe2+ loaded phyllosilicates is sparse. Here we present an investigation of the Fe2+ exchanged vermiculites from Santa Olalla and Ojén (Andalusia, Spain) by means of Mössbauer spectroscopy. The room temperature Mössbauer spectra are very similar to those of the starting compounds (Na forms) except for a decrease of the contribution of structural Fe3+ and a concomitant increase of the contribution of Fe2+ sites, indicating an internal redox process. The extent of this redox reaction is different for the two vermiculites. Thus, the intercalated Fe2+ acts as an electron mediator from the external medium to the structural Fe3+ ions. A new component attributable to intercalated Fe2+ is practically invisible in the room temperature Mössbauer spectra, but increases strongly and continuously during cooling to 4.2 K, where it is the dominant feature of the Mössbauer patterns. At 4.2 K, its quadruple splitting amounts to 3.31 mm/s, which is in excellent agreement with the quadrupole slitting of Fe2+ coordinated to six water molecules in a highly symmetric octahedral arrangement. The strong decrease of the Mössbauer-Lamb factor of this component with increasing temperature indicates a weak bonding of the Fe 2+ in the interlayer space

Current Status, Perspectives, and Future Directions of Multivessel Disease and Left Main Coronary Disease: Its Treatment by PCI or Surgery

MVD has evolved from an era where it was mandatory to treat all lesions, even very thin vessels. With the advent of more realistic anatomical scores such as the ERACI score and the gradient measurements with the fractional flow of reserve (FFR) and instantaneous wave-free ratio (iwFR), a more conservative era has begun, which benefits the patient in the long-term follow-up. The treatment of the LMCA remains a challenging lesion because of the amount of irrigation. It can be divided the treatment of the LMCA with a low or high ERACI score, in the first group is where the PCI has gained in confidence and dedication in addition to knowledge and bifurcation techniques. The second group with high score can only be performed in centers with high PCI experience, since their alternative will always be surgical as the first choice. The revascularization in MVD with STEMI, the priority is the culprit vessel and then evaluate the underlying lesions, an invasive or with a functional test in the short term. The patient with DM is a singular patient, and its treatment should always be evaluated by a multidisciplinary team. We believe that patients with low ERACI score have the possibility of being treated with PCI, but patients with high score are surgical

Nudging Youth to Develop Savings Habits: Experimental Evidence Using SMS Messages

In this working paper, we report on a field experiment articulating financial information via cellphone text messages and financial decisions among low-income youth in Colombia. For twelve months, youth accountholders are randomly assigned to receive either: (a) monthly financial education messages, (b) monthly savings reminders, (c) semimonthly reminders, or (d) control. After 12 months, account balances in monthly and semimonthly reminders groups increase by 28% and 43%, respectively, relative to controls. Financial education messages do not increase balances. Over two thirds of balance increases in reminder groups are net savings. Savings effects of reminders last eight months after youth stop receiving messages

The complete mitogenome of the trilobite beetle, Platerodrilus sp. (Elateroidea: Lycidae)

The nucleotide sequence of the complete mitogenome of the trilobite beetle, Platerodrilus sp. was determined. This is the first complete mitogenome reported for the family Lycidae (Elateroidea: Coleoptera). The newly determined sequence is 16,394 bp long and shows a relatively high AT content (76.2%). The gene arrangement of the trilobite beetle mt genome is the same found in other related beetle mitogenomes. The reconstructed tree recovered Elateroidea as a strongly supported monophyletic group but could not resolve phylogenetic relationships among studied elateroid families, including Lycidae.Spanish Ministry of Science and Innovation, 10.13039/501100004837 [CGL2013-45211-C2-2-P], [BES-2011-051469,CGL2013-45211-C2-2-P] and [CGL2015-66571-P MINECO/FEDER].Peer reviewe

Thermal discrete dipole approximation for near-field radiative heat transfer in many-body systems with arbitrary nonreciprocal bodies

The theoretical study of many-body effects in the context of near-field radiative heat transfer (NFRHT) has already led to the prediction of a plethora of thermal radiation phenomena. Special attention has been paid to nonreciprocal systems in which the lack of the Lorentz reciprocity has been shown to give rise to unique physical effects. However, most of the theoretical work in this regard has been carried out with the help of approaches that consider either pointlike particles or highly symmetric bodies (such as spheres), which are not easy to realize and explore experimentally. In this work we develop a many-body approach based on the thermal discrete dipole approximation (TDDA) that is able to describe the NFRHT between nonreciprocal objects of arbitrary size and shape. We illustrate the potential and the relevance of this approach with the analysis of two related phenomena, namely the existence of persistent thermal currents and the photon thermal Hall effect, in a system with several magneto-optical bodies. Our many-body TDDA approach paves the way for closing the gap between experiment and theory that is hindering the progress of the topic of NFRHT in many-body systemsJ.C.C. acknowledges funding from the Spanish Ministry of Science and Innovation (Grant No. PID2020-114880GB-I00

Luminescent and Scintillating Properties of Lanthanum Fluoride Nanocrystals in Response to Gamma/Neutron Irradiation: Codoping with Ce Activator, Yb Wavelength Shifter, and Gd Neutron Captor

A novel concept for detection and spectroscopy of gamma rays, and detection of thermal neutrons based on codoped lanthanum fluoride nanocrystals containing gadolinium is presented.The trends of colloidal synthesis of the mentioned material, LaF3 co-doped with Ce as the activator, Yb as the wavelength-shifter and Gd as the neutron captor, is reported. Nanocrystals of the mentioned material were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), optical absorption, and photoluminescence spectroscopy. Gamma detection and its potential spectroscopy feature have been confirmed. The neutron detection capability has been confirmed by experiments performed using a 252Cf neutron source.Comment: 5 figures, 16 page

Mirador Comedor Emergente

74 p.Mirador Comedor Emergente es un proyecto de Ctulo de la Escuela de arquitectura de la Universidad de Talca que trata de un comedor de temporeros para un predio agrícola de viñas y manzanos llamado Gajardo & Compañía, ubicado en el kilómetro 3 de la ruta J-- 665, del Camino El Maitén, Los Niches, Curicó. El comedor busca satisfacer una necesidad actual del campo, en donde los trabajadores actualmente almuerzan en el piso. Para ello se desarrolla este proyecto en busca de satisfacer a actual necesidad de los 15 trabajadores que trabajan las faenas de cosecha y vendimia del predio. Entonces, el principal objetivo del proyecto es lograr un buen comer, y solucionar la actual necesidad. Se busca lograr que los usuarios , mediante la obra logren reconocer el paisaje en donde se desempeñan desde otro punto lograr en cierta medida que escapen de la sensación de trabajo llegada al suelo que logren mediante el proyecto emerger por sobre el paisaje llegando así a un nuevo recon0cimiento del mismo. La obra fue concebida en base a materiales de deshecho reales, madera de bins de deshecho, retazos de alambre reciclado de replantaciones de parrones rocas sobrantes de procesos de defensas fluviales, y malla desechada de packins vecinos. El proyecto no se busca mas que satisfacer la necesidad de un buen comedor a través de la arquitectura y los medios contractivos utilizados por el campesin

ABC and Hamiltonian Monte-Carlo methods in COGARCH models

The analysis of financial series, assuming calendar effects and unequally spaced times over continuous time, can be studied by means of COGARCH models based on Lévy processes. In order to estimate the COGARCH model parameters, we propose to use two different Bayesian approaches. First, we suggest to use a Hamiltonian Montecarlo (HMC) algorithm that improves the performance of standard MCMC methods. Secondly, we introduce an Approximate Bayesian Computational (ABC) methodology which allows to work with analytically infeasible or computationally expensive likelihoods. After a simulation and comparison study for both methods, HMC and ABC, we apply them to model the behaviour of some NASDAQ time series and we discuss the results