Assessing math anxiety in elementary schoolchildren through a Spanish version of the Scale for Early Mathematics Anxiety (SEMA)

Math anxiety (MA) affects students of all age groups. Because of its effects on children’s academic development, the need to recognize its early manifestations has been highlighted. We designed a European-Spanish version of the Scale for Early Mathematics Anxiety (SEMA; Wu et al. (2012)), and assessed its psychometric properties in a sample of children aged 7 to 12 years. The participants (967 typically developing children) were elementary school students recruited from ten schools. Children reported their general and math anxiety levels in an individual session and performed nonverbal IQ and math abilities subtests in a group session. Teachers reported the final math grades. The psychometric indices obtained, and the resulting factor structure revealed that the European-Spanish version of the SEMA developed in this study is a reliable and valid measure to evaluate MA in children from 3rd to 6th grade. Moreover, we explored gender differences, that resulted in small effect sizes, which disappeared when controlling for trait anxiety. Differences across grades were found for both global MA and the numerical processing anxiety factor but not for the situational and performance anxiety factor. Finally, MA was negatively associated with students’ math achievement, although the strength of the associations varied with the MA measure selected, the kind of math achievement analyzed, and the school stage considered. Our findings highlight the relevance of MA in elementary school and highlight the need for an early identification of students at risk of suffering MA to palliate the negative consequences of MA in children’s cognitive and academic development

Extension of formal conjugations between diffeomorphisms

We study the formal conjugacy properties of germs of complex analytic diffeomorphisms defined in the neighborhood of the origin of ${\mathbb C}^{n}$. More precisely, we are interested on the nature of formal conjugations along the fixed points set. We prove that there are formally conjugated local diffeomorphisms $\phi, \eta$ such that every formal conjugation $\hat{\sigma}$ (i.e. $\eta \circ \hat{\sigma} = \hat{\sigma} \circ \phi$) does not extend to the fixed points set $Fix (\phi)$ of $\phi$, meaning that it is not transversally formal (or semi-convergent) along $Fix (\phi)$. We focus on unfoldings of 1-dimensional tangent to the identity diffeomorphisms. We identify the geometrical configurations preventing formal conjugations to extend to the fixed points set: roughly speaking, either the unperturbed fiber is singular or generic fibers contain multiple fixed points.Comment: 34 page

Effortful control is associated with children's school functioning via learning-related behaviors

The goal of the current study was to identify factors that contribute to individual differences in school functioning. We proposed a model including direct effects of Effortful Control (EC) on Spanish 6- to 12-year olds' (N = 142) academic achievement and social adaptation at school, with these relations partially mediated by learning-related behaviors (LRBs). Parents rated children's EC; teachers reported children's LRBs and children' social adaptation in school; children' social preference was assessed through classmates' nominations. Children's academic achievement was measured through standard tests and grades. Analyses were run using structural equation models, controlling by gender, intelligence, age, socioeconomic status, and school. EC was positively and directly related to social adaptation in school. EC was also indirectly related to academic achievement and social adaptation through LRBs. The findings highlight the potential relevance of children's EC and LRBs for adjustment in elementary school

Measurement of sub-pulse-width temporal delays via spectral interference induced by weak value amplification

We demonstrate experimentally a scheme to measure small temporal delays, much smaller than the pulse width, between optical pulses. Specifically, we observe an interference effect, based on the concepts of quantum weak measurements and weak value amplification, through which a sub-pulse-width temporal delay between two femtosecond pulses induces a measurable shift of the central frequency of the pulse. The amount of frequency shift, and the accompanying losses of the measurement, can be tailored by postselecting different states of polarization. Our scheme requires only spectrum measurements and linear optics elements, hence greatly facilitating its implementation. Thus it appears to be a promising technique for measuring small and rapidly varying temporal delays.Peer ReviewedPostprint (published version

Role of the spectral shape of quantum correlations in two-photon virtual-state spectroscopy

The true role of entanglement in two-photon virtual-state spectroscopy (Saleh et al 1998 Phys. Rev. Lett. 80 3483), a two-photon absorption spectroscopic technique that can retrieve information about the energy level structure of an atom or a molecule, is controversial. The consideration of closely related techniques, such as multidimensional pump–probe spectroscopy (Roslyak et al 2009 Phys. Rev. A 79, 063409), suggests that spectroscopic information might also be retrieved by using uncorrelated pairs of photons. Here we show that this is not the case. In the two-photon absorption process, the ability to obtain information about the energy level structure of a medium depends on the spectral shape of existing temporal (frequency) correlations between the absorbed photons. In fact, it is a combination of both the presence of frequency correlations (entanglement) and their specific spectral shape that makes the realization of two-photon virtual-state spectroscopy possible. This result helps in selecting the type of two-photon source that needs to be used in order to experimentally perform the two-photon virtual-state spectroscopy technique.Peer ReviewedPostprint (published version

Genetic differentiation between two geographic subpopulations of Bermeya goat

Ponencia publicada en ITEA, vol.104Este trabajo es un análisis preliminar de la diversidad y grado de diferenciación genética entre las subpoblaciones Oriental y Occidental de la cabra de raza Bermeya de Asturias. Se han genotipado 27 microsatélites en 122 individuos pertenecientes a las poblaciones de cabra Bermeya Oriental, Bermeya Occidental, del Guadarrama, Alpine y Saanen. Las poblaciones de raza Bermeya presentaron heterocigosis esperadas menores de 0,6 y coascendencias moleculares dentro de población de 0,419, reflejando una alta identidad genética entre individuos. Asimismo, el número medio de alelos por locus, ajustado por el tamaño muestral, de las poblaciones Bermeya Oriental y Occidental fueron los menores encontrados (3,8 y 3,9, respectivamente). La mayor coascendencia molecular se encontró entre las poblaciones Bermeya Oriental-Guadarrama (0,388 ± 0,006), como consecuencia de la introgresión, en el Oriente asturiano de individuos de tipo Pirenáico. Este parámetro entre las poblaciones de Bermeya Oriental y Occidental fue de 0,371 ± 0,007. Puede ser necesario establecer estrategias de conservación diferenciadas para las dos poblaciones geográficas de cabra Bermeya.Two geographic subpopulations (Eastern and Western) of the Asturian Bermeya goat were analysed using 27 microsatellites. A total of 122 individuals of Bermeya, Guadarrama, Alpine and Saanen goat breeds were genotyped. The Eastern and Western Bermeya subpopulations had expected heterozygosity values lower than 0.6 and within-subpopulations molecular coancestry values of 0.419, thus illustrating a high between individuals genetic identity. The rarefacted average number of alleles per locus found in both the Eastern and the Western Bermeya subpopulations were the lowest in the dataset (3.8 and 3.9, respectively). The higher between-populations molecular coancestry values was found for the pair Eastern Bermeya-Guadarrama (0.388 ± 0.006), thus reflecting the introgression of the Pyrenean-type goat into Eastern Asturias. This parameter between the two Bermeya subpopulations was of 0.371 ± 0.007. It could be recommended the implementation of different conservation strategies for each of the geographic subpopulations of Bermeya goat

Los procesos para la canonización de san Francisco Javier

The article analyzes the complicated itinerary that followed the various processes of canonization of the cause of St. Francis Xavier until the his canonization in 1622. These processes, which took place in two stages, are notable for the a variety of geographical settings where they had place and by the number of witnesses who intervened. The first five trials (1556-1557) were carried out by order of King John III of Portugal. The second group is made up of nine pontifical processes (called «remisoriales»), held between 1610 and 1617 within the framework of the cause of canonization carried carried out by the Congregation of Rites by order of Pope Paul V.El artículo analiza el complicado itinerario que siguieron los diversos procesos de canonización de la causa de san Francisco Javier hasta la plasmación en su canonización de 1622. Estos procesos, que se desarrollaron en dos etapas, destacan por la gran variedad de escenarios geográficos donde tuvieron lugar y por la cantidad de testigos que intervinieron. Los cinco primeros procesos (1556-1557) fueron realizados por orden del rey Juan III de Portugal. El segundo grupo está formado por nueve procesos pontificios (llamados «renisoriales»), celebrados entre 1610 y 1617 en el marco de la causa de canonización llevada a cabo por la Congregación de los Ritos por orden del papa Paulo V

Fármacocinética del genérico zidovudina en pacientes cubanos infectados por el virus de la inmunodeficiencia humana

Agradecemos al personal médico y de enfermería del Hospital del Instituto “Pedro Kourí” que atendió a los pacientes incluidos en el estudio. Así como al técnico Ramón Caro que ayudó en la preparación de soluciones y muestras.Objetivo: El objetivo del presente trabajo es caracterizar los parámetros farmacocinéticos de la zidovudina (AZT) en pacientes cubanos seropositivos al virus de la inmunodeficiencia humana (VIH). Materiales y métodos: Para ello se realizó un estudio de dosis única (300mg) a 13 pacientes “naives” seropositivos al VIH-1 donde se midieron, según la cinética establecida, las concentraciones de AZT en plasma y orina. Estas concentraciones se determinaron por cromatografía líquida de alta resolución en fase reversa (RP-HPLC) con detección UV (λ=267nm). Resultados: Los parámetros farmacocinéticos fueron calculados usando técnicas estándares no compartimentales. Entre las variables determinadas están: Concentración máxima (Cmax= 3,35±1,41 μg/mL), Recobrado urinario (RU= 25,36±9,25%), Aclaramiento renal (ClR= 17,56±7,78L/h), Aclaramiento plasmático (CLp= 47,09±29,45 L/h), Tiempo de vida media de eliminación (t½= 1,19±0,30h) y Biodisponibilidad relativa (F= 63,12±16,59%). Conclusiones: Los valores de los parámetros calculados posibilitan la caracterización del perfil farmacocinético del genérico cubano AZT. Esto es útil para posteriores correcciones de los regímenes de dosificación según las especificidades de cada paciente.Aims: The purpose of this study was to characterize pharmacokinetic parameters of zidovudine generic (AZT) in human inmunodeficiency virus (HIV) infected cuban patients. Materials and methods: A single-dose study (300mg AZT) was made in 13 ¨naive¨ patientes for determination of the AZT concentrations in plasma and urine, fallowed an established kinetic. These concentration values were measured by reversed-phase liquid chromatography (RP-HPLC) with UV detection (λ=267nm). Results: Pharmacokinetic parameters for zidovudine were estimated from data of concentration in plasma and urine versus time by using noncompartmental methods. The most important parameters obtained were: maximum concentration (Cmax= 3,35±1,41 μg/mL), urinary recovery (UR= 25,36±9,25 %), renal clearance (ClR= 17,56±7,78L/h), plasmatic clearance (CLp= 47,09±29,45 L/h), terminal elimination half-life (t½= 1,19±0,30h), and apparent bioavailability (F= 63,12±16,59%). Conclusions: The values of pharmacokinetic parameters made possible to the establishment of the pharmacokinetic profile for the Cuban generic zidovudine. This is very important for future dose adjustment of patients

The zeta-function of a quasi-ordinary singularity.II.

Depto. de Álgebra, Geometría y TopologíaFac. de Ciencias MatemáticasTRUEpu

Estudio de la resistencia mecánica a la compresión de ladrillos elaborados a partir de mezclas arcilla roja-cemento Portland

A proposal for the development of handcrafted bricks of clay soil stabilized with gray portland cement, as an alternative to reduce the level of pollution caused by emissions of carbon dioxide from the use of wood as a source of combustion during the baking step of bricks is presented. The work was carried out in the soil bank of one brickyard located in La Paz Centro, Nicaragua. Moreover, two different brands of Portland cement were used. Cement/soil samples were prepared according to the established norms, and the mechanical-physical properties were compared with bricks cooked through a full mixed factorial design experiment. The parameters studied were ratios of cement /soil, water /cement binder and cement brand. The best results for samples of cement/soil reached resistances higher than 12 MPa after 28 days of curing and absorption percentages lower than 15%. Hydration products, responsible for the development of mechanical strength, were analyzed using infrared spectroscopy. The largest number of hydrated calcium silicate was obtained for samples with Canal cement. DOI: http://dx.doi.org/10.5377/nexo.v27i2.1945Se presenta una propuesta para la elaboración de ladrillos artesanales a base del suelo arcilloso estabilizado con cementoPortland gris, como alternativa para reducir el grado de contaminación causado por emisiones de dióxido de carbono a causadel uso de madera, usada como fuente de combustión durante la etapa de cocción de los ladrillos elaborados artesanalmente anivel nacional. Se trabajó básicamente con el banco de suelo de una de las ladrilleras ubicada en La Paz Centro, Nicaragua ydos marcas diferentes de cemento portland. Se elaboraron muestras de cemento/suelo según las normas y se compararon laspropiedades físico mecánicas con los ladrillos cocidos por medio de un diseño de experimento de tipo factorial mixto completo.Los factores que se estudiaron fueron las porciones de cemento/suelo, agua/ligante y marca de cemento. Los mejores resultadospara muestras de cemento/suelo presentaron resistencias superiores a los 12 MPa después de 28 días de curado y porcentajes deabsorción inferiores al 15%. Los productos de hidratación responsables del desarrollo de la resistencia mecánica se analizaronpor medio de pruebas de espectroscopia infrarroja, mostrando la mayor cantidad de silicatos de calcio hidratado en muestras concemento Canal.DOI: http://dx.doi.org/10.5377/nexo.v27i2.194