A short note on the nested-sweep polarized traces method for the 2D Helmholtz equation

We present a variant of the solver in Zepeda-N\'u\~nez and Demanet (2014), for the 2D high-frequency Helmholtz equation in heterogeneous acoustic media. By changing the domain decomposition from a layered to a grid-like partition, this variant yields improved asymptotic online and offline runtimes and a lower memory footprint. The solver has online parallel complexity that scales \emph{sub linearly} as $\mathcal{O} \left( \frac{N}{P} \right)$, where $N$ is the number of volume unknowns, and $P$ is the number of processors, provided that $P = \mathcal{O}(N^{1/5})$. The variant in Zepeda-N\'u\~nez and Demanet (2014) only afforded $P = \mathcal{O}(N^{1/8})$. Algorithmic scalability is a prime requirement for wave simulation in regimes of interest for geophysical imaging.Comment: 5 pages, 5 figure

The Cost of Biotechnology Regulation in the Philippines

This paper identifies direct costs and opportunity costs of bio-safety regulation for four transgenic products in the Philippines: Bt eggplant, Bt rice, ringspot-virus resistant papaya, and virus resistant tomatoes. It finds that direct regulatory costs while significant, are generally smaller than the research costs for technology development. However, both research and regulatory costs are overshadowed by even a relatively brief delay in product release, which may occur due to unexpected regulatory delays.Food Consumption/Nutrition/Food Safety, Research and Development/Tech Change/Emerging Technologies,

Catalizadores heterogéneos utilizados para la obtención de biodiesel

El ahorro energético y el cuidado medioambiental son de gran importancia en todos los países, debido a estos aspectos se ha desarrollado la búsqueda de combustibles alternos para sustituir los provenientes defuentes fósiles. En este artículo se presenta información relacionada con los diferentes catalizadores utilizados para la producción de biodiesel, mencionando su clasificación química y física, también se citan las propiedades químicas y las características morfológicas que los hacen ser una opción apropiada para utilizarlos en la reacción de transesterificación, la cual está implicada en la producción de biodiesel. Además, se resalta la importancia de los catalizadores heterogéneos por sus características de baja contaminación al medio ambiente, su capacidad de ser reutilizados y porque pueden separarse fácilmente del producto

Study through Geant4, for Time Resolution characterization of different detectors arrays coupled with two SiPMs, as a function of: the scintillator plastic material, its volumetric dimensions and the location of the radiation emission source

The high time resolution detectors are relevant in those experiments or simulations were the particles to detect, have a very short time of flight (TOF), and due this it´s required that the detections times are ranged between ns. & ps.Using Geant4 software, it was made thirty simulations of coupled detectors to plastic scintillators with two silicon photomultipliers (SiPMs) located on the scintillator’s central sides. To characterize the time resolution, it was required to quantify the optical photons that reach the Score in a certain time, which are generated by muons on the surface of the plastic scintillator. Different configurations of muon beams were simulated at energy of 1 GeV, to interact with the configuration of the scintillator material of its corresponding arrangement. The simulations were made varying three parameters: the scintillator material “BC404 & BC422”, its size, and the location of the radiation source. Fifteen simulations correspond to BC404 material & fifteen simulations to BC422 material respectively. The first five simulations consisted in varying the scintillator’s volumetric size and collocate the muons beam guided randomly distributed over it, the next five simulations differentiate from setting up a directly centered beam, and the last five simulations for guide the beam on the left lower corner of each scintillator.The best time resolution achieved was σ= 8.67 +/− 0.26 ps., reported by the detector with BC422 scintillator material which has a volume of 20x20x3 mm3

Measurement of Content of 226Ra in Drinking Water From Some States of Mexican Republic by Liquid Scintillation Method

To assess the quality of drinking water in respect to the content of radioactivity, usually is carried out an screening program in the locations of interest, that program consist in pick representative samples of drinking water from the wells in that locations, water samples are analyzed to measuring the gross alpha/beta radioactivity by a low background proportional counter or a liquid scintillation system. When some sample exceeds the normative limit then it must be known which radionuclides are in that sample. Expected radionuclides in water are the NORM (normal occurring radioactive material) from the natural radioactive chains. 226Ra is frequently present in drinking water and is one of most important radionuclide because its “radiotoxicity”, the WHO [World Health Organization, Guidelines for drinking-water Quality, (2016)] recommends a reference level for 226Ra of 1 Bq/L (the dose coefficient for 226Ra is 2.8 x 10-7 Sv/Bq). From a national program of drinking water screening in the Mexican Republic, the samples that exceeded the national normative limits were picked again in the same well and analyzed by LS (liquid Scintillation), using the method of two phases with a not water miscible scintillator cocktail. Results of concentrations of 226Ra from drinking water are presented. In general the content of 226Ra in drinking water samples was lower that the guide values recommended for the WHO

Chromosome structural variants: Epidemiology, identification and contribution to human diseases

Editorial on the Research Topic: Chromosome structural variants: Epidemiology, identification and contribution to human diseases.Human chromosome structural variants (SVs) are balanced/unbalanced genomic abnormalities that include translocation, inversion, insertion, and deletion/duplication (also known as copy-number variants, CNVs) events with a size of >50 bp. Currently, the capability of genome sequencing in the research and clinical fields has increased our capacity to detect cryptic SVs and further delineate the complexity of karyotypically/microarray detectable SVs. This has increased our knowledge of pathogenicity mechanisms by considering dysregulation of gene expression through position effects and complex interactions between gene dosage and mutational burden. However, much of the contribution of SVs to human disease is left to explore, as the incidence of SVs is still underestimated owing to limitations of current sequencing technologies and analytical pipelines, and few studies have comprehensively integrated SV information with single nucleotide variants in congenital diseases. Rigorous investigation of SV pathogenicity is warranted for clinical applications. The Research Topic in this issue is divided into three main sections: three articles demonstrate methodologies in SV identification and pathogenicity annotation; five papers discuss the spectrum of SVs in individuals with different indications; and two reports characterize sequence complexity of SVs [...].CCM acknowledges NIH P01 GM061354 and support by the NIHR Manchester Biomedical Research Centreinfo:eu-repo/semantics/publishedVersio

Hegemonia e precariedade acadêmica: a educação universitária no Chile em tempos de Covid 19

Resumen: La emergencia sanitaria ha evidenciado una serie de nudos críticos relacionados con el campo educativo. En este sentido, el cómo se relacionan los sujetos es un aspecto importante a considerar. El presente artículo intenciona la discusión sobre cuáles podrían ser las tensiones que genera la posición de poder de los académicos en una universidad regional. Con el propósito de realizar esta discusión, se analizaron los postulados relativos a la reproducción social de Bourdieu y al concepto de dispositivo de Foucault. Asimismo, se describe la relación hegemónica establecida por algunos académicos y sus posibles efectos en el proceso de enseñanza aprendizaje. El fenómeno descrito, entendido como la hegemonía pedagógica se comporta como un dispositivo de poder basado en el concepto etnocéntrico que posee el rol desempeñado por académicos, docentes de esta institución. Desde una perspectiva anclada en Bourdieu, esta práctica es esencialmente pragmática con características coercitivas las cuales no son evidentes aunque sí son validadas por los sujetos en relaciones intersubjetivas. La negación del habitus de los estudiantes universitarios es ejercido tanto por esta casa de estudio como por quienes ejercen docencia en ella: la institución no ha realizado procesos de revisión, cuestionamiento ni espacios de reflexión tipo claustro para discutir con respecto a la práctica pedagógica frente a la diferencia.Abstract: The pandemic has evidenced a series of problems regarding the educational field. In this sense, how individuals from a specific educational institution relate is a crucial aspect to consider. This article attempts to discuss the stress provoked by the power relations that the academic staff hold at a public university. In order to carry out this pondering, Bourdieu´s views on social reproduction and Focault´s dispositive are analysed. Additionally, the results of these hegemonic practices within the teaching learning process are describedResumo: A emergência sanitária revelou uma série de nós críticos relacionados ao campo educacional. Nesse sentido, a forma como os assuntos se relacionam é um aspecto importante a ser considerado. Este artigo tem como objetivo discutir quais poderiam ser as tensões geradas pela posição de poder dos acadêmicos em uma universidade regional. Com o objetivo de realizar essa discussão, foram analisados os postulados relacionados à reprodução social de Bourdieu e ao conceito de dispositivo de Foucault. Da mesma forma, descreve-se a relação hegemônica estabelecida por alguns acadêmicos e seus possíveis efeitos no processo ensino-aprendizage