Technical advantages for weak value amplification: When less is more

The technical merits of weak value amplification techniques are analyzed. We consider models of several different types of technical noise in an optical context and show that weak value amplification techniques (which only use a small fraction of the photons) compare favorably with standard techniques (which uses all of them). Using the Fisher information metric, we demonstrate that weak value techniques can put all of the Fisher information about the detected parameter into a small portion of the events and show how this fact alone gives technical advantages. We go on to consider a time correlated noise model, and find that a Fisher information analysis indicates that while the standard method can have much larger information about the detected parameter than the postselected technique. However, the estimator needed to gather the information is technically difficult to implement, showing that the inefficient (but practical) signal-to-noise estimation of the parameter is usually superior. We also describe other technical advantages unique to imaginary weak value amplification techniques, focusing on beam deflection measurements. In this case, we discuss combined noise types (such as detector transverse jitter, angular beam jitter before the interferometer and turbulence) for which the interferometric weak value technique gives higher Fisher information over conventional methods. We go on to calculate the Fisher information of the recently proposed photon recycling scheme for beam deflection measurements, and show it further boosts the Fisher information by the inverse postselection probability relative to the standard measurement case

Inferring broken detailed balance in the absence of observable currents

Identifying dissipation is essential for understanding the physical mechanisms underlying nonequilibrium processes. {In living systems, for example, the dissipation is directly related to the hydrolysis of fuel molecules such as adenosine triphosphate (ATP)}. Nevertheless, detecting broken time-reversal symmetry, which is the hallmark of dissipative processes, remains a challenge in the absence of observable directed motion, flows, or fluxes. Furthermore, quantifying the entropy production in a complex system requires detailed information about its dynamics and internal degrees of freedom. Here we introduce a novel approach to detect time irreversibility and estimate the entropy production from time-series measurements, even in the absence of observable currents. We apply our technique to two different physical systems, namely, a partially hidden network and a molecular motor. Our method does not require complete information about the system dynamics and thus provides a new tool for studying nonequilibrium phenomena.Comment: 14 pages, 6 figure

Investigating the effectiveness of spatial frequencies to the left and right of central vision during reading:Evidence from reading times and eye movements

Printed words are complex visual stimuli containing a range of different spatial frequencies, and several studies have suggested that various spatial frequencies are effective for skilled adult reading. But while it is well known that the area of text from which information is acquired during reading extends to the left and right of each fixation, the effectiveness of spatial frequencies falling each side of fixation has yet to be determined. To investigate this issue, we used a spatial frequency adaptation of the gaze-contingent moving-window paradigm in which sentences were shown to skilled adult readers either entirely as normal or filtered to contain only low, medium, or high spatial frequencies except for a window of normal text around each point of fixation. Windows replaced filtered text either symmetrically 1 character to the left and right of each fixated character, or asymmetrically, 1 character to the left and 7 or 13 to the right, or 1 character to the right and 7 or 13 to the left. Reading times and eye-movement measures showed that reading performance for sentences presented entirely as normal generally changed very little with filtered displays when windows extended to the right but was often disrupted when windows extended to the left. However, asymmetrical windows affected performance on both sides of fixation. Indeed, increasing the leftward extent of windows from 7 to 13 characters produced decreases in both reading times and fixation durations, suggesting that reading was influenced by the spatial frequency content of leftward areas of text some considerable distance from fixation. Overall, the findings show that while a range of different spatial frequencies can be used by skilled adult readers, the effectiveness of spatial frequencies differs for text on each side of central vision, and may reflect different roles played by these two areas of text during reading

Programa de alfabetización en los medios de comunicación para reducir el bullying en adolescentes.

El objetivo de esta investigación fue implementar un programa de alfabetización en medios de comunicación para reducir los índices de bullying en adolescentes. La investigación se realizó con adolescentes de primer año de secundaria del municipio de Nezahualcóyotl, teniendo como muestra dos grupos: el grupo control tuvo un total de 29 adolescentes y el grupo intervención 29 adolescentes, su edad oscilaba entre 11 y 14. Se utilizaron dos cuestionarios tipo Likert, el primero de 29 ítems permitió identificar situaciones de bullying presenciados, realizados y vividos. El segundo cuestionario de 22 ítems, permitió identificar cuáles son los programas de televisión que más ven los adolescentes y de qué manera estos influyen en sus actividades cotidianas. Los resultados encontrados para la presente investigación mostraron que el primer cuestionario presenta una Alfa total de Cronbach de 0.82 y el segundo una puntuación de 0.79 indicando que ambos cuestionarios son buenos y consistentes

Integral transformation solution of free-space cylindrical vector beams and prediction of modified-Bessel-Gaussian vector beams

A unified description of the free-space cylindrical vector beams is presented, which is an integral transformation solution to the vector Helmholtz equation and the transversality condition. The amplitude 2-form of the angular spectrum involved in this solution can be arbitrarily chosen. When one of the two elements is zero, we arrive at either transverse-electric or transverse-magnetic beam mode. In the paraxial condition, this solution not only includes the known $J_1$ Bessel-Gaussian vector beam and the axisymmetric Laguerre-Gaussian vector beam that were obtained by solving the paraxial wave equations, but also predicts two new kinds of vector beam, called the modified-Bessel-Gaussian vector beam.Comment: 8 pages and 1 figur

Evaluating Neural Language Models as Cognitive Models of Language Acquisition

The success of neural language models (LMs) on many technological tasks has brought about their potential relevance as scientific theories of language despite some clear differences between LM training and child language acquisition. In this paper we argue that some of the most prominent benchmarks for evaluating the syntactic capacities of LMs may not be sufficiently rigorous. In particular, we show that the template-based benchmarks lack the structural diversity commonly found in the theoretical and psychological studies of language. When trained on small-scale data modeling child language acquisition, the LMs can be readily matched by simple baseline models. We advocate for the use of the readily available, carefully curated datasets that have been evaluated for gradient acceptability by large pools of native speakers and are designed to probe the structural basis of grammar specifically. On one such dataset, the LI-Adger dataset, LMs evaluate sentences in a way inconsistent with human language users. We conclude with suggestions for better connecting LMs with the empirical study of child language acquisition.Comment: To appear in the GenBench 2023 workshop proceedings, the first workshop on (benchmarking) generalisation in NLP. GenBench 2023 will be held at EMNLP 2023 on December 6, 202

Efectos de las medidas para mitigar la propagación del COVID-19 en las decisiones de viaje y uso del tiempo en Ecuador

Las medidas restrictivas impuestas por los gobiernos para mitigar la propagación del COVID-19 han provocado cambios importantes en la realización de actividades y patrones de movilidad de las personas en todo el mundo. Esta investigación tiene como objetivo comprender los efectos de la cuarentena adoptada en Ecuador entre el 27 de abril y el 24 de mayo del 2020 en el uso del tiempo y las decisiones de viaje, junto con identificar quienes fueron los grupos poblacionales más afectados y así plantear políticas orientadas a preservar el bienestar de todas las personas ante la posibilidad de una nueva pandemia en el futuro. El estudio utilizó datos de preferencias reveladas obtenidos a través de una encuesta online, los cuales permitieron capturar los cambios en los hábitos diarios de los ecuatorianos y como difieren entre grupos socioeconómicos, antes y durante la pandemia. Los condicionantes socioeconómicos que influencian las prácticas de movilidad durante la pandemia fueron estudiados mediante modelos de elección discreta como Logit Multinomial (MNL) y Logit Ordinal (OL). Además, se estudiaron los cambios en el uso del tiempo mediante modelos discretos-continuos (MDCEV) con la finalidad de modelar conjuntamente la elección de realizar múltiples actividades y su duración. Los resultados permitieron identificar cambios en las decisiones de viaje y uso del tiempo que evidencian las desigualdades que han experimentado diferentes grupos sociales durante la pandemia y así lograr plantear lineamientos políticos que contribuyan a mejorar la calidad de vida y el bienestar de las personas a través de una movilidad segura y equitativa durante la fase de reconstrucción posterior al COVID-19 y ante la posibilidad de una nueva pandemia.MaestríaMagister en Ingeniería Civi

Impact of Synonymous Genome Recoding on the HIV Life Cycle

Synonymous mutations within protein coding regions introduce changes in DNA or messenger (m) RNA, without mutating the encoded proteins. Synonymous recoding of virus genomes has facilitated the identification of previously unknown virus biological features. Moreover, large-scale synonymous recoding of the genome of human immunodeficiency virus type 1 (HIV-1) has elucidated new antiviral mechanisms within the innate immune response, and has improved our knowledge of new functional virus genome structures, the relevance of codon usage for the temporal regulation of viral gene expression, and HIV-1 mutational robustness and adaptability. Continuous improvements in our understanding of the impacts of synonymous substitutions on virus phenotype - coupled with the decreased cost of chemically synthesizing DNA and improved methods for assembling DNA fragments - have enhanced our ability to identify potential HIV-1 and host factors and other aspects involved in the infection process. In this review, we address how silent mutagenesis impacts HIV-1 phenotype and replication capacity. We also discuss the general potential of synonymous recoding of the HIV-1 genome to elucidate unknown aspects of the virus life cycle, and to identify new therapeutic targets

Analytical maximum likelihood estimation of stellar magnetic fields

The polarised spectrum of stellar radiation encodes valuable information on the conditions of stellar atmospheres and the magnetic fields that permeate them. In this paper, we give explicit expressions to estimate the magnetic field vector and its associated error from the observed Stokes parameters. We study the solar case where specific intensities are observed and then the stellar case, where we receive the polarised flux. In this second case, we concentrate on the explicit expression for the case of a slow rotator with a dipolar magnetic field geometry. Moreover, we also give explicit formulae to retrieve the magnetic field vector from the LSD profiles without assuming mean values for the LSD artificial spectral line. The formulae have been obtained assuming that the spectral lines can be described in the weak field regime and using a maximum likelihood approach. The errors are recovered by means of the hermitian matrix. The bias of the estimators are analysed in depth.Comment: accepted for publication in MNRA

Crystalline-Size Dependence of Dual Emission Peak on Hybrid Organic Lead-Iodide Perovskite Films at Low Temperatures

In this work, we have investigated the crystalline-size dependence of optical absorption and photolumines-cence emission of CH3NH3PbI3 films, which is necessary to identify the potencial practical applications of the gadgets based on perovskite films. This study was carried out at low temperatures to minimize the extra complexity induced by thermal effects. The purpose was clarifying the origin of the dual emission peak previously reported in literature. We have found that the grain-size is responsible of the appearance or disappearance of this dual emission on CH3NH3PbI3 at low temperatures, whereas we have inferred that the thickness of the perovskite layer is a much more important factor than the size of the grains in the location of the energy of the bandgap. Moreover, the increase in the grain size allows slowing down the phase transition. Additionally, we evidence a decrease in the effective Rydberg energy of the exciton in several samples, from 23-25 meV at 7 K to 12-13 meV at 165 K, by fitting to Elliot-Toyozawa theory. We have extracted other im-portant physical parameters of perovskites from the photoluminescence-data deconvolution, such as bandgap, exciton-phonon interaction and exciton binding energy. A new phase transition at 45.5 K was determined by the temperature dependence of full width at half maximum and integrated intensity of the photoluminescence, and it was confirmed by the radiative lifetime obtained from the time-resolved photoluminescence emission by mean of time-correlated single photon counting at different temperatures, excitation fluencies and emission energies