Vibrating soap films: An analog for quantum chaos on billiards

We present an experimental setup based on the normal modes of vibrating soap films which shows quantum features of integrable and chaotic billiards. In particular, we obtain the so-called scars -narrow linear regions with high probability along classical periodic orbits- for the classically chaotic billiards. We show that these scars are also visible at low frequencies. Finally, we suggest some applications of our experimental setup in other related two-dimensional wave phenomena.Comment: 5 pages, 7 figures. Better Postscript figures available on reques

Agility in primary education students: differences by age and gender

Se evaluó la agilidad en 110 niños (63 chicos y 47 chicas) divididos en dos grupos de alumnos de educación primaria: (a) Grupo 1 (G1) (n=53): alumnos de 1º curso (6.3±0.6 años), y (2) Grupo 2 (G2) (n=57): alumnos de 4º curso (9.5±0.4 años). Se utilizó una modificación respecto al MAT (28) para la valoración de la agilidad: el MAT2. Los propósitos del estudio fueron cuantificar el nivel de agilidad de los dos grupos, comprobar la influencia de las variables edad y sexo en la agilidad en edades tempranas y determinar la fiabilidad y reproducibilidad del test MAT2 en niños de 6 y 9 años. Se han obtenido diferencias significativas (p<0.05) entre los resultados generales obtenidos por el G1 (9.76±0.90 s) y el G2 (8.29±0.80 s). En el análisis realizado en cada grupo no se han encontrado diferencias significativas atendiendo al sexo en el G1 pero si en el G2. Se han obtenido buenos valores de fiabilidad en el test MAT2.Agility was assessed in 110 children (63 boys and 47 girls) divided into two groups: (a) Group 1 (G1) (n=53): first year student in primary education (age: 6.3±0.6 years) and (b) Group 2 (G2) (n=57): fourth year students in primary education (age: 9.5±0.4 years). A modified version of MAT (28) was used to determine agility: MAT2. The purposes of the study were to assess the agility level of the two groups, verify the influence of age and gender in agility performance at an early age and determine the reliability and reproducibility of MAT2. Good reliability values were found in MAT2. Significant differences (p<0.05) were found between general results of G1 (9.76±0.90 s) and G2 (8.29±0.80 s). No significant results were found according to gender in G1 but if in G2 (p<0.05)

Optimization of DNA recovery and amplification from non-carbonized archaeobotanical remains

Ancient DNA (aDNA) recovered from archaeobotanical remains can provide key insights into many prominent archaeological research questions, including processes of domestication, past subsistence strategies, and human interactions with the environment. However, it is often difficult to isolate aDNA from ancient plant materials, and furthermore, such DNA extracts frequently contain inhibitory substances that preclude successful PCR amplification. In the age of high-throughput sequencing, this problem is even more significant because each additional endogenous aDNA molecule improves analytical resolution. Therefore, in this paper, we compare a variety of DNA extraction techniques on primarily desiccated archaeobotanical remains and identify which method consistently yields the greatest amount of purified DNA. In addition, we test five DNA polymerases to determine how well they replicate DNA extracted from non-charred ancient plant remains. Based upon the criteria of resistance to enzymatic inhibition, behavior in quantitative real-time PCR, replication fidelity, and compatibility with aDNA damage, we conclude these polymerases have nuanced properties, requiring researchers to make educated decisions as to which one to use for a given task. The experimental findings should prove useful to the aDNA and archaeological communities by guiding future research methodologies and ensuring precious archaeobotanical remains are studied in optimal ways, and may thereby yield important new perspectives on the interactions between humans and past plant communities

One-Loop Yang-Mills Integrands from Scattering Equations

We investigate in the context of the scattering equations, how one-loop linear propagator integrands in gauge theories can be linked to integrands with quadratic propagators using a double forward limit. We illustrate our procedure through examples and demonstrate how the different parts of the derived quadratic integrand are consistent with cut-integrands derived from four-dimensional generalized unitarity. We also comment on applications and discuss possible further generalizations.Comment: 20 pages, 6 figures, typos corrected, added clarifications and comments. Version to be published in PR

Recommending audio mixing workflows

This paper describes our work on Audio Advisor, a workflow recommender for audio mixing. We examine the process of eliciting, formalising and modelling the domain knowledge and expert’s experience. We are also describing the effects and problems associated with the knowledge formalisation processes. We decided to employ structured case-based reasoning using the myCBR 3 to capture the vagueness encountered in the audio domain. We detail on how we used extensive similarity measure modelling to counter the vagueness associated with the attempt to formalise knowledge about and descriptors of emotions. To improve usability we added GATE to process natural language queries within Audio Advisor. We demonstrate the use of the Audio Advisor software prototype and provide a first evaluation of the performance and quality of recommendations of Audio Advisor

Fish associated with floating drifting objects as a feeding resource for Balearic Shearwaters Puffinus mauretanicus during the breeding season

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Effects of different contextual interference programs in agility (Efectos producidos por diferentes programas de interferencia contextual en la agilidad)

En este estudio participaron 76 alumnos de 9-10 años de edad de un colegio público de educación primaria (44 chicos y 32 chicas). Los participantes fueron randomizados en función del resultado del pretest en cuatro grupos: interferencia contextual baja (ICB, n=19), interferencia contextual moderada (ICM, n=19) interferencia contextual alta (ICA, n=19) y Grupo Control (GC, n=19). El objetivo de este estudio fue conocer que método de entrenamiento de la agilidad en función de la interferencia contextual baja, moderada o alta (ICB, ICM e ICA) es más efectivo en escolares de cuarto curso de educación primaria, con el fin de dilucidar qué método de desarrollo de esta capacidad resultó el idóneo en esta etapa de escolarización. La agilidad fue evaluada mediante el test MAT2. Salvo en el grupo control (CG), se obtuvieron diferencias significativas en la agilidad (test MAT2), en todos los grupos después de un programa de intervención de 4 semanas de duración en alumnos del cuarto curso de primaria. Estas diferencias han sido superiores en el grupo de ICM (p<0,01, ES=1,12). Se encontraron diferencias significativas (p<0,05, ES=0,79) en el postest entre el grupo de ICM e ICB. This study involved 76 students from 9-10 years old in a public elementary school (44 boys and 32 girls). Participants were randomized to the outcome of the pretest into four groups: low contextual interference (ICB, n = 19), moderate contextual interference (ICM, n = 19) high contextual interference (ICA, n = 19) and Control Group (GC, n = 19). The aim of this study was to determine which method of agility training (ICB, ICM or ICA) is more effective in primary school children (9-10 years), in order to figure out what method of development of this capacity was the appropriate at this stage of schooling. The agility was evaluated by MAT2 test. Except in the control group (GC), there were significant differences in agility (MAT2 test) in all groups (ICB, ICM and ICA) after an intervention program of 4-week fourth-year students of elementary school. These differences have been higher in the ICM group (p<0.01, ES=1.12). We found significant differences (p<0.05, ES=0.79) in the posttest between the ICM and ICB group

Utility of a Short Neuropsychological Protocol for Detecting HIV-Associated Neurocognitive Disorders in Patients with Asymptomatic HIV-1 Infection

Human Immunodeficiency Virus type 1 (HIV-1) infection is a chronic disease that affects ~40 million people worldwide. HIV-associated neurocognitive disorders (HAND) are common in individuals with HIV-1 Infection, and represent a recent public health problem. Here we evaluate the performance of a recently proposed short protocol for detecting HAND by studying 60 individuals with HIV-1-Infection and 60 seronegative controls from a Caribbean community in Barranquilla, Colombia. The short evaluation protocol used significant neuropsychological tests from a previous study of asymptomatic HIV-1 infected patients and a group of seronegative controls. Brief screening instruments, i.e., the Mini-mental State Examination (MMSE) and the International HIV Dementia Scale (IHDS), were also applied. Using machine-learning techniques, we derived predictive models of HAND status, and evaluated their performance with the ROC curves. The proposed short protocol performs exceptionally well yielding sensitivity, specificity, and overall prediction values >90%, and better predictive capacity than that of the MMSE and IHDS. Community-specific cut-off values for HAND diagnosis, based on the MMSE and IHDS, make this protocol suitable for HAND screening in individuals from this Caribbean community. This study shows the effectivity of a recently proposed short protocol to detect HAND in individuals with asymptomatic HIV-1-Infection. The application of community-specific cut-off values for HAND diagnosis in the clinical setting may improve HAND screening accuracy and facilitate patients’ treatment and follow-up. Further studies are needed to assess the performance of this protocol in other Latin American populations

Spectroscopic and Theoretical Study of CuI Binding to His111 in the Human Prion Protein Fragment 106-115

The ability of the cellular prion protein (PrPC) to bind copper in vivo points to a physiological role for PrPC in copper transport. Six copper binding sites have been identified in the nonstructured N-terminal region of human PrPC. Among these sites, the His111 site is unique in that it contains a MKHM motif that would confer interesting CuI and CuII binding properties. We have evaluated CuI coordination to the PrP(106-115) fragment of the human PrP protein, using NMR and X-ray absorption spectroscopies and electronic structure calculations. We find that Met109 and Met112 play an important role in anchoring this metal ion. CuI coordination to His111 is pH-dependent: at pH >8, 2N1O1S species are formed with one Met ligand; in the range of pH 5-8, both methionine (Met) residues bind to CuI, forming a 1N1O2S species, where N is from His111 and O is from a backbone carbonyl or a water molecule; at pH <5, only the two Met residues remain coordinated. Thus, even upon drastic changes in the chemical environment, such as those occurring during endocytosis of PrPC (decreased pH and a reducing potential), the two Met residues in the MKHM motif enable PrPC to maintain the bound CuI ions, consistent with a copper transport function for this protein. We also find that the physiologically relevant CuI-1N1O2S species activates dioxygen via an inner-sphere mechanism, likely involving the formation of a copper(II) superoxide complex. In this process, the Met residues are partially oxidized to sulfoxide; this ability to scavenge superoxide may play a role in the proposed antioxidant properties of PrPC. This study provides further insight into the CuI coordination properties of His111 in human PrPC and the molecular mechanism of oxygen activation by this site.Fil: Arcos López, Trinidad. Instituto Politécnico Nacional. Centro de Investigación y de Estudios Avanzado; MéxicoFil: Qayyum, Munzarin. University of Stanford; Estados UnidosFil: Rivillas Acevedo, Lina. Instituto Politécnico Nacional. Centro de Investigación y de Estudios Avanzado; MéxicoFil: Miotto, Marco César. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones para el Descubrimiento de Fármacos de Rosario. Universidad Nacional de Rosario. Instituto de Investigaciones para el Descubrimiento de Fármacos de Rosario; Argentina. Max Planck Laboratory for Structural Biology; ArgentinaFil: Grande Aztatzi, Rafael. Instituto Politécnico Nacional. Centro de Investigación y de Estudios Avanzado; MéxicoFil: Fernandez, Claudio Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones para el Descubrimiento de Fármacos de Rosario. Universidad Nacional de Rosario. Instituto de Investigaciones para el Descubrimiento de Fármacos de Rosario; Argentina. Max Planck Laboratory for Structural Biology; ArgentinaFil: Hedman, Britt. University of Stanford; Estados UnidosFil: Hodgson, Keith O.. University of Stanford; Estados UnidosFil: Vela, Alberto. Instituto Politécnico Nacional. Centro de Investigación y de Estudios Avanzado; MéxicoFil: Solomon, Edward I.. University of Stanford; Estados UnidosFil: Quintanar, Liliana. Instituto Politécnico Nacional. Centro de Investigación y de Estudios Avanzado; Méxic