Interaction-induced chaos in a two-electron quantum-dot system

A quasi-one-dimensional quantum dot containing two interacting electrons is analyzed in search of signatures of chaos. The two-electron energy spectrum is obtained by diagonalization of the Hamiltonian including the exact Coulomb interaction. We find that the level-spacing fluctuations follow closely a Wigner-Dyson distribution, which indicates the emergence of quantum signatures of chaos due to the Coulomb interaction in an otherwise non-chaotic system. In general, the Poincar\'e maps of a classical analog of this quantum mechanical problem can exhibit a mixed classical dynamics. However, for the range of energies involved in the present system, the dynamics is strongly chaotic, aside from small regular regions. The system we study models a realistic semiconductor nanostructure, with electronic parameters typical of gallium arsenide.Comment: 4 pages, 3ps figure

Emotional Intelligence in Times of Covid-19: a Comparative Study in Peruvian Universities

Objective:The aim of the study was to compare emotional intelligence in Peruvian university students from public and private universities.Theoretical framework: In higher education, emotionally intelligent students have the ability to interact appropriately with others, achieve good academic results, and reach personal and professional goals.Method: The methodology was descriptive-comparative, the sample consisted of 838 university students of both sexes from public (471) and private (364) universities belonging to the coast, highlands and jungle regions of Peru. A sociodemographic form created for the study and the emotional intelligence scale (TMMS-24) were used as measurement instruments.Results and conclusion:The results showed that university students over 30 years of age, women, those from the highlands and those who worked had high levels of emotional intelligence.Implications of the research:It is necessary for university institutions to reorganize their academic conditions and provide the necessary inputs to apply socioemotional strategies to students. Researchers linked to the lines of research on emotional intelligence should develop predictive studies to know which factors may be predicting adequate or inadequate emotional intelligence in university students.Originality:This study demonstrates that it is essential to attend to and provide emotional intelligence tools to those students whodo not have the necessary resources to face different situations in the face of the COVID-19 pandemic and contributes to the training of educators, especially environmental educators in crisis contexts

Efecto genotóxico y citotóxico del plomo en meristemos radiculares de dos variedades de Vicia faba L. y su relación con la domesticación

Las problemáticas ambientales asociadas al incremento de metales pesados como el plomo han promovido la búsqueda de bioindicadores eficientes; Vicia faba es uno de los más utilizados, sin embargo, su aprovechamiento a nivel mundial ha provocado el uso indistinto de sus variedades silvestres y domesticadas, sin considerar las implicaciones del proceso de domesticación. Por tal motivo, la presente investigación tiene como objetivo evaluar el efecto genotóxico y citotóxico del plomo en células meristemáticas de raíz de semillas de V. faba  silvestre y de la variedad Major (domesticada) a través de la presencia de micronúcleos y la determinación del índice mitótico, con la finalidad de conocer sus respuestas ante este metal y su relación con la domesticación, así como sugerir el uso de la variedad más sensible como bioindicador. Para ello, los meristemos radiculares se sometieron a tratamientos con 0, 0.005, 0.01 y 0.02 g L-1 de acetato de plomo y se realizaron tinciones con aceto-orceína; se obtuvo la frecuencia de micronúcleos y el índice mitótico por cada 1000 células observadas. Los resultados obtenidos indican que el acetato de plomo tiene un efecto genotóxico y citotóxico diferencial entre ambas variedades, siendo V. faba var. Major la que presenta una alta sensibilidad al metal pesado, debido a una pérdida en la resistencia al estrés, por lo que se sugiere su uso como bioindicador; mientras que en las semillas silvestres mostraron mayor tolerancia al tener un bajo grado de domesticación

Inclusión de harinas de follajes arbóreos y arbustivos tropicales (morus alba; erythrina poeppigiana; tithonia diversifolia e hibiscus rosa-sinensis) en la alimentación de cuyes (cavia porcellus linnaeus)

La investigación se ejecutó en la Finca Experimental “La María” propiedad de la Universidad Técnica Estatal de Quevedo (UTEQ) localizada en el km 71/2 de la vía Quevedo-Mocache; Provincia de Los Ríos cuya ubicación geográfica de 1º 6’ 23” de latitud sur y 79º 29’ 12” de longitud oeste y a una altura de 73 msnm. El objetivo principal fue evaluar el comportamiento productivo con la inclusión del 20% de harinas arbustivas y arbóreas tropicales.  Se utilizaron 40 cuyes machos de 30 días de edad. Se empleó un diseño completamente al azar con cinco tratamientos, cuatro réplicas y la unidad experimental estuvo conformado por 2 cuyes. Para determinar las diferencias entre medias de tratamientos se aplicó la prueba de Tukey (P≤0,05). Se evaluaron cinco tratamientos en dietas de: (T0) dieta 100% balanceado, (T1) 80% dieta y 20% harina de Morus alba, (T2) 80% dieta y 20% harina de Erythrina poeppigiana, (T3) 80% dieta y 20% harina de Tithonia diversifolia, (T4) 80% dieta y 20% harina de Hibiscus rosa-sinensis. Las variables bajo estudio fueron: Consumo de alimento de balanceado en materia seca g (CABMS), ganancia de peso g (GP), índice de conversión alimenticia (ICA) y rendimiento a la canal % (RC). La rentabilidad de los tratamientos se la determinó a través de la relación beneficio-costo (R b/c). El mayor (P and lt;0,01) CABMS; GP-ICA; RC-Rentabilidad, la registraron los tratamientos: T0 (48,34 g MS animal-1 d-1); T1 (8,80 g animal-1 d-1 y 5,04) y el T3 (77,67% y 26,20%, respectivamente)

Body weight impact of the sugar- sweetened beverages tax in Mexican children: A modeling study

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156213/3/ijpo12636_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156213/2/ijpo12636-sup-0001-supinfo.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156213/1/ijpo12636.pd

Monitoreo de la actividad enzimática de las lipasas intracelulares de Ustilago maydis expresada durante el crecimiento en limitación de nitrógeno y su correlación en reacciones lipolíticas

Under nitrogen starvation, Ustilago maydis forms lipid droplets (LDs). Although the dynamics of these organelles are known in the literature, the identity of the lipases implicated in their degradation is unknown. We determined lipase activity and identified the intracellular lipases expressed during growth under nitrogen starvation and YPD media by zymograms. The results showed that cytosolic extracts exhibited higher lipase activity when cells were grown in YPD. Under nitrogen starvation, lipase activity was not detected after 24 h of culture, resulting in lipid accumulation in LDs. This suggests that these lipases could be implicated in LD degradation. In the zymogram, two bands, one of 25 and the other of 37 kDa, presented lipase activity. The YPD extracts showed lipase activity in olive and almond oils, which contain triacylglycerols with mono and polyunsaturated fatty acids. This is the first report about U. maydis cytosolic lipases involved in LD degradation.En ausencia de nitrógeno, Ustilago maydis forma cuerpos lipídicos (LDs). Aunque se conoce la dinámica de estos organelos, se desconoce la identidad de las lipasas implicadas en su degradación. En este estudio se determinó la actividad de lipasa, y se identificaron las lipasas intracelulares expresadas durante el crecimiento sin nitrógeno y en YPD mediante zimogramas. Los extractos citosólicos de células en YPD exhibieron mayor actividad de lipasa. En medio sin nitrógeno no se detectó actividad de lipasa después de 24 h de cultivo, presentándose acumulación de lípidos en los LDs. Esto sugiere que estas lipasas podrían implicarse en la degradación de los LDs. En el zimograma bandas de 25 y 37 kDa, presentaron actividad de lipasa. Los extractos de células cultivadas en YPD hidrolizaron triacilgliceroles compuestos de ácidos grasos mono y poliinsaturados. Este es el primer reporte sobre lipasas citosólicas de U. maydis implicadas en la degradación de LDs

General Microbiota of the Soft Tick Ornithodoros turicata Parasitizing the Bolson Tortoise (Gopherus flavomarginatus) in the Mapimi Biosphere Reserve, Mexico

The general bacterial microbiota of the soft tick Ornithodoros turicata found on Bolson tortoises (Gopherus flavomarginatus) were analyzed using next generation sequencing. The main aims of the study were to establish the relative abundance of bacterial taxa in the tick, and to document the presence of potentially pathogenic species for this tortoise, other animals, and humans. The study was carried-out in the Mapimi Biosphere Reserve in the northern-arid part of Mexico. Bolson tortoises (n = 45) were inspected for the presence of soft ticks, from which 11 tortoises (24.4%) had ticks in low loads (1–3 ticks per individual). Tick pools (five adult ticks each) were analyzed through 16S rRNA V3–V4 region amplification in a MiSeq Illumina, using EzBioCloud as a taxonomical reference. The operational taxonomic units (OTUs) revealed 28 phyla, 84 classes, 165 orders, 342 families, 1013 genera, and 1326 species. The high number of taxa registered for O. turicata may be the result of the variety of hosts that this tick parasitizes as they live inside G. flavomarginatus burrows. While the most abundant phyla were Proteobacteria, Actinobacteria, and Firmicutes, the most abundant species were two endosymbionts of ticks (Midichloria-like and Coxiella-like). Two bacteria documented as pathogenic to Gopherus spp. were registered (Mycoplasma spp. and Pasteurella testudinis). The bovine and ovine tick-borne pathogens A. marginale and A. ovis, respectively, were recorded, as well as the zoonotic bacteria A. phagocytophilum,Coxiella burnetii, and Neoehrlichia sp. Tortoises parasitized with O. turicata did not show evident signs of disease, which could indicate a possible ecological role as a reservoir that has yet to be demonstrated. In fact, the defense mechanisms of this tortoise against the microorganisms transmitted by ticks during their feeding process are still unknown. Future studies on soft ticks should expand our knowledge about what components of the microbiota are notable across multiple host–microbe dynamics. Likewise, studies are required to better understand the host competence of this tortoise, considered the largest terrestrial reptile in North America distributed throughout the Chihuahuan Desert since the late Pleistocene

Spectral study of heat treatment process of wheat flour by VIS/SW-NIR image system

The capability of the VIS/SW-NIR (visible/short wave near infrared) hyperspectral imaging system to characterize the heat treatment process of cake wheat flour was studied. Combinations of heat treatments of flour were run at different temperatures (80, 100 and 130 °C) and for various times (10, 20 and 30 min). The resulting treated flours were analyzed by the imaging technique. The hyperspectral results, studied by multivariate statistical methods, showed a pattern evolution of the flours treated by different heat treatments. The wavelengths that contributed the most, and implied in the differentiations, were detected. The selection of wavelengths allowed us to optimize the analysis, which reduced from 54 to 6 wavelengths. To ensure that the VIS/SW-NIR information depended on the heat treatment influence on flours, cakes were produced and characterized according to height, mass loss during the baking process, crumb structure and textural properties. The VIS/SW-NIR imaging analysis was capable of following the changes that occurred during the different heat treatments of flours. VIS/SW-NIR was applied to determine and adjust the heat treatment process variables to improve the features of flours during the cake production process.Verdú Amat, S.; Ivorra Martínez, E.; Sánchez Salmerón, AJ.; Barat Baviera, JM.; Grau Meló, R. (2016). Spectral study of heat treatment process of wheat flour by VIS/SW-NIR image system. Journal of Cereal Science. 71:99-107. doi:10.1016/j.jcs.2016.08.008S991077

A search for point sources of EeV photons

Measurements of air showers made using the hybrid technique developed with the fluorescence and surface detectors of the Pierre Auger Observatory allow a sensitive search for point sources of EeV photons anywhere in the exposed sky. A multivariate analysis reduces the background of hadronic cosmic rays. The search is sensitive to a declination band from -85{\deg} to +20{\deg}, in an energy range from 10^17.3 eV to 10^18.5 eV. No photon point source has been detected. An upper limit on the photon flux has been derived for every direction. The mean value of the energy flux limit that results from this, assuming a photon spectral index of -2, is 0.06 eV cm^-2 s^-1, and no celestial direction exceeds 0.25 eV cm^-2 s^-1. These upper limits constrain scenarios in which EeV cosmic ray protons are emitted by non-transient sources in the Galaxy.Comment: 28 pages, 10 figures, accepted for publication in The Astrophysical Journa