588 research outputs found
Mathematical modelling of mass transfer phenomena for sucrose and lactitol molecules during osmotic dehydration of cherries
The diffusion phenomena of sucrose and lactitol in cherries using different proportions during osmotic dehydration was quantified by means of a mathematical model based on Fick's second law. The average effective diffusion coefficient for soluble solids in skin and flesh are 5.37 10−11 m2∕s and 1.24 10−10 m2∕s. Whereas, for water in skin and flesh are 9.27 10−09 m2∕s and 5.48 10−08 m2∕s. A significant difference for water diffusion coefficients (p < 0.05) was observed between the treatments. This could indicate that the diffusion between species and treatments is differential. Effective diffusion coefficients for water in skin and flesh are 2 orders of magnitude greater than effective diffusion coefficients for soluble solids. This is probably due to its lesser molecular weight. Furthermore, the effective diffusion coefficients for water and soluble solids in cherry skin are between 1 and 2 orders of magnitude lower than effective diffusion coefficients for both in cherry flesh, possibly due to the barrier effect exerted by the cherry skin.Fil: Maldonado, Mariela Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Tecnológica Nacional; ArgentinaFil: González Pacheco, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Tecnológica Nacional; Argentin
Antioxidant activity of alkyl gallates and glycosyl alkyl gallates in fish oil in water emulsions: Relevance of their surface active properties and of the type of emulsifier
The antioxidant activity of gallic acid and a series of alkyl gallates (C4-C18) and glycosylated alkyl gallates (C4-C18) on fish oil-in-water emulsions was studied. Three types of emulsifiers, lecithin, Tween-20 and sodium dodecyl sulphate (SDS) were tested. A nonlinear behavior of the antioxidant activity of alkyl gallates when increasing alkyl chain length was observed for emulsions prepared with lecithin. Medium-size alkyl gallates (C6-C12) were the best antioxidants. In contrast, for emulsions prepared with Tween-20, the antioxidants seem to follow the polar paradox. Glucosyl alkyl gallates were shown previously to be better surfactants than alkyl gallates. Nevertheless, they exhibited a worse antioxidant capacity than their corresponding alkyl gallates, in emulsions prepared with lecithin or Tween-20, indicating the greater relevance of having three OH groups at the polar head in comparison with having improved surfactant properties but just a di-ortho phenolic structure in the antioxidant
Evaluación probabilística de fragilidad sísmica para las estructuras de HA, en los barrios periféricos occidentales de la ciudad de Loja.
Earthquakes represent a significant natural hazard, regularly affecting lives and the built environment in earthquake-prone areas around the world, causing social and economic losses, (Guha-Sapir et al., 2016). The HAZUS methodology exhibits a simple, precise and advanced approach for the development of fragility curves, and the estimation of damage (light, moderate, extensive and collapse) of the infrastructures before seismic action, (Patel & Vasanwala, 2019). In Ecuador, municipal governments do not act as an effective urban regulatory agent, it is because there is still a predominance of informal construction. At the local level, in the western zone of the city of Loja, peripheral neighborhoods with reinforced concrete buildings are located, which in a large percentage are built without an earthquake-resistant design, for this reason, this research work aims to analyze and estimate the probability of seismic damageLos sismos representan un peligro natural importante, que afecta regularmente las vidas y el entorno construido en áreas propensas a terremotos en todo el mundo, provocando pérdidas sociales y económicas, (Guha-Sapir et al., 2016). La metodología HAZUS exhibe un enfoque simple, preciso y avanzado para el desarrollo de curvas de fragilidad, y la estimación de daño (leve, moderado, extenso y colapso) de las infraestructuras ante la acción sísmica, (Patel & Vasanwala, 2019). En el Ecuador los gobiernos municipales no actúan como un agente regulador urbano eficaz, es por cuanto, aún existe la predominancia de la construcción informal. A nivel local, en la zona occidental de la ciudad de Loja, se localizan barrios periféricos con edificaciones de hormigón armado, los cuales en un gran porcentaje se encuentran construidos sin un diseño sismorresistente, por esta razón, este trabajo de investigación pretende analizar y estimar la probabilidad de daño sísmico
Learning Effect in a Multilingual Web-Based Argumentative Writing Instruction Model, Called ECM, on Metacognition, Rhetorical Moves, and Self-Efficacy for Scientific Purposes
This research was developed within the framework of ED.INVEST (HUM356) Research Groups financed by the Junta de Andalucia (Spain), with the project "Multilingual Communication and Citizenship Technologies" and the project "Accessible scientific writing course in Moodle to be taught in Spanish, German, English, Italian, and Catalan", financed by the Department of Planning Quality and Evaluation at the University of Granada. Reference PID14-05/Code 14-05.The purpose of this study is to assess the learning effect of a multilingual web-based
argumentative writing instruction model called the Ensayo Científico Multilingüe (ECM, Multilingual
Scientific Essay) adapting the didactic model called Genre-based Writing Instruction (GBWI) in
an experiment conducted over three months. For this purpose, a quasi-experimental research
model was applied to 150 students in the experimental group and 150 in the control group, with
two measurements, pre and post-test, for three dependent variables: (a) writing metacognition
and its dimensions; (b) written argumentative self-efficacy; and (c) rhetorical moves and steps
of an argumentative essay. The latter variable was measured by the content analysis method.
Variables (a) and (b) were both measured with instruments validated in a population of 518 university
students using structural equations. The findings demonstrate the positive effect of the ECM, which
combines WBWI and GBWI in argumentative written learning in the students’ mother tongue in all
variables measured, applying statistics such as the Shapiro–Wilk statistic, parametric contrast, and
the Wilcoxon signed-rank test. In relation to the findings, with respect to the evaluated variables,
it was discovered, specifically, that the rhetorical steps in which the students showed a significant
improvement were innovations, quotes/research, definitions of concepts, refutations, definitive
reasons, and bibliographical references. Likewise, the rhetorical steps that did not present significant
differences following the application of the ECM were discovered, and they were: reason summary,
formulation of premise, and reasons for. Furthermore, it can be stated that for the ECM there was
an increase, above all, in awareness of the following metacognitive dimensions: (a) writing selfregulation;
(b) writing planning; and (c) writing revision, as well as argumentative self-efficacy. The
novelties of this research with respect to the precedents reside in that it offers valid and concrete
results on the effect of a multilingual web design integrated into a well-defined didactic model of
argumentative writing on writing metacognition and its dimensions, argumentative structuring
and its rhetorical steps, and argumentative self-efficacy. The related studies consider only some of
these variables, but not all of them together or their complexity. These results have allowed us to
establish specific didactic–technological proposals for improving the ECM that are transferable to
didactic designs to guide written argumentation at higher academic levels using multilingual web
technologies and integrating the metacognitive, behavioral, and motivational dimensions of writing.Junta de Andalucia
European Commission HUM356Department of Planning Quality and Evaluation at the University of Granada PID14-05/Code 14-0
Descripción y resultados de un programa de animación a la lectura
[Resumen] Se describe la intervención en animación a la lectura llevada a cabo en 298 alumnas de 8° de E.G.B. para conseguir una actividad lectora continuada. Se presentan los resultados obtenidos a lo largo del programa experimental relacionados con la actividad lectora conseguida, las estrategias de lectura utilizadas, la permanencia del efecto del programa en las alumnas, así como la posible influencia de dicha actividad lectora en la composición escrita de los mismos sujetos, para lo cual es utilizado un grupo de control
One Cut‐Point Phase‐Type Distributions in Reliability. An Application to Resistive Random Access Memories
A new probability distribution to study lifetime data in reliability is introduced in this
paper. This one is a first approach to a non‐homogeneous phase‐type distribution. It is built by
considering one cut‐point in the non‐negative semi‐line of a phase‐type distribution. The density
function is defined and the main measures associated, such as the reliability function, hazard rate,
cumulative hazard rate and the characteristic function, are also worked out. This new class of dis‐
tributions enables us to decrease the number of parameters in the estimate when inference is con‐
sidered. Additionally, the likelihood distribution is built to estimate the model parameters by
maximum likelihood. Several applications considering Resistive Random Access Memories com‐
pare the adjustment when phase type distributions and one cut‐point phase‐type distributions are
considered. The developed methodology has been computationally implemented in R‐cran.This paper is partially supported by the project FQM‐307 of the Government of Andalu‐
sia (Spain), by the project PID2020‐113961GB‐I00 of the Spanish Ministry of Science and Innovation
(also supported by the European Regional Development Fund program, ERDF) and by the project
PPJIB2020‐01 of the University of Granada. Additionally, the first and second authors acknowledge
financial support by the IMAG–María de Maeztu grant
CEX2020‐001105‐M/AEI/10.13039/501100011033. They also acknowledge the financial support of
the Consejería de Conocimiento, Investigación y Universidad, Junta de Andalucía (Spain) and the
FEDER programme for projects A.TIC.117.UGR18, IE2017‐5414, B.TIC.624.UGR20 and
A‐FQM‐66‐UGR20
Compromiso protector del omento mayor en una ruptura uterina asintomática en una perra : reporte de un caso
ABSTRACT: The great omentum plays an important role in protecting the peritoneal cavity from bacteria and contaminating material and providing the peritoneum with leukocytes from the omental milky spots (OMS). However, there are no reports on the existence of OMS in dogs. In this report an unusual case of asymptomatic uterine rupture (UR) is described in a 16 month old pointer bitch that was admitted at the CES University Veterinary Clinic in Medellin (Colombia) for elective neutering. In the abdominal surgical plane, the great omentum was found sequestering abundant macerated fetal debris and uterine content released near the ruptured uterine wall. A severe congestive and brown-like appearance of peritoneum suggesting a protective inflammatory process was observed. All uterine contents, uterus and compromised great omentum were completely removed. The dog recovered satisfactorily with no clinical complications after a long term postsurgical period. Additionally we discuss the existence of OMS in the canine omentum.RESUMEN: El omento mayor juega un papel importante en la protección de la cavidad peritoneal contra infecciones bacterianas y material contaminante proporcionando leucocitos al peritoneo producidos en los puntos lechosos del omento (OMS). Sin embargo, en la literatura científica no hay reportes sobre la existencia de los OMS en caninos. En este reporte es descrito un caso poco usual de ruptura uterina (UR) asintomática en una perra de la raza pointer de 16 meses de edad, que fue atendida en la consulta del Centro de Medicina Veterinaria y Zootecnia de la Universidad CES en Medellín (Colombia) para ser sometida a ovariohisterectomía electiva. Una vez fue alcanzado el plano quirúrgico abdominal el omento mayor fue encontrado recubriendo una cantidad abundante de restos fetales macerados y otro contenido uterino que había sido liberado a la cavidad peritoneal cerca al sitio de ruptura de la pared uterina. El omento presentaba un aspecto de congestión severa de color parduzco, que sugería una reacción inflamatoria intensa. Todo el útero y el contenido revertido a la cavidad fueron removidos quirúrgicamente, como también el omento mayor. La perra se recuperó de manera satisfactoria sin complicaciones clínicas después de un largo periodo posterior a la cirugía. En la discusión es planteada la existencia de los OMS en el omento canino
Ultrasonography and physiological description of essential events for reproductive management in dairy cattle. Review
El ultrasonido permite visualizar el tracto reproductivo femenino y ayuda a comprender algunos de los eventos reproductivos más relevantes como el desarrollo folicular y del cuerpo lúteo, la ovulación, el diagnóstico de gestación, las infecciones uterinas, el crecimiento embrionario y fetal, entre otros. Hoy en día, existe una gran cantidad de información sobre la fisiología y la ultrasonografía de los eventos reproductivos mencionados anteriormente. Sin embargo, el abrumador número de artículos disponibles revisa los aspectos técnicos de la ultrasonografía, la fisiología y el manejo reproductivo por separado. Por lo tanto, el objetivo de la presente revisión es fusionar una descripción fisiológica con el manejo reproductivo y los aspectos técnicos de imágenes de ultrasonido originales de los eventos reproductivos más relevantes en el ganado lechero, para promover el uso de ultrasonido durante el manejo reproductivo del ganado lechero por parte de profesionales e investigadores.The ultrasound allows to visualize the female reproductive tract and helps to understand some of the most relevant reproductive events such as follicular and corpus luteum development, ovulation, pregnancy diagnosis, uterine infections, embryo and fetal growth, among others. Nowadays, there is a massive amount of information regarding the physiology and ultrasonography of the reproductive events mentioned above. However, the overwhelming number of available papers review technical aspects of ultrasonography, physiology and reproductive management separately. Therefore, the objective of the present review is to merge a physiological description with reproductive management and technical aspects of original ultrasound pictures of the most relevant reproductive events in dairy cattle to promote ultrasound use during dairy cattle reproductive management by practitioners and researchers
Experticia del ajedrecista desde una perspectiva microfenomenológica
Diferentes investigaciones han abordado el fenómeno de cómo el jugador de ajedrez alcanza un nivel alto de experticia; sin embargo, la gran mayoría se han llevado a cabo desde una perspectiva en tercera persona, es decir, sin tomar en cuenta la experiencia subjetiva del ajedrecista. El presente trabajo tiene como objetivos: 1) analizar la experticia de ajedrecistas de nivel proficiente desde una perspectiva fenomenológica, esto es, desde la experiencia subjetiva del jugador; 2) señalar los estados internos que parecen ser cognitivamente relevantes en las acciones de los ajedrecistas; 3) teorizar sobre el eventual papel que juega la intuición en las acciones de los jugadores de ajedrez. Para ello se realizó un estudio exploratorio con cinco jugadores de ajedrez durante una competencia de corte nacional en México, utilizando como método la entrevista microfenomenológica propuesta por Claire Petitmengin. Los resultados indican que hay regularidades en los estados internos de los jugadores a nivel intra e interpersonal asociadas implícitamente a momentos críticos de las partidas. Lo anterior permite ofrecer una definición operacional de la intuición y afirmar que esta, en efecto, forma parte de los procesos cognitivamente relevantes de los ajedrecistas de nivel proficiente, aunque las acciones de estos aún dependen, en buena medida, de los cálculos explícitos que realizan durante los momentos críticos
Label-free detection of nosocomial bacteria using a nanophotonic interferometric biosensor
Nosocomial infections are a major concern at the worldwide level. Early and accurate identification of nosocomial pathogens is crucial to provide timely and adequate treatment. A prompt response also prevents the progression of the infection to life-threatening conditions, such as septicemia or generalized bloodstream infection. We have implemented two highly sensitive methodologies using an ultrasensitive photonic biosensor based on a bimodal waveguide interferometer (BiMW) for the fast detection of Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA), two of the most prevalent bacteria associated with nosocomial infections. For that, we have developed a biofunctionalization strategy based on the use of a PEGylated silane (silane-PEG-COOH) which provides a highly resistant and bacteria-repelling surface, which is crucial to specifically detect each bacterium. Two different biosensor assays have been set under standard buffer conditions: One based on a specific direct immunoassay employing polyclonal antibodies for the detection of P. aeruginosa and another one employing aptamers for the direct detection of MRSA. The biosensor immunoassay for P. aeruginosa is fast (it only takes 12 min) and specific and has experimentally detected concentrations down to 800 cfu mL (cfu: Colony forming unit). The second one relies on the use of an aptamer that specifically detects penicillin-binding protein 2a (PBP2a), a protein only expressed in the MRSA mutant, providing a photonic biosensor with the ability to identify the resistant pathogen MRSA and differentiate it from methicillin-susceptible S. aureus (MSSA). Direct, label-free, and selective detection of whole MRSA bacteria has been achieved, making possible the direct detection of also 800 cfu mL. According to the signal-to-noise (S/N) ratio of the device, a theoretical limit of detection (LOD) of around 49 and 29 cfu mL was estimated for P. aeruginosa and MRSA, respectively. Both results obtained under standard conditions reveal the great potential this interferometric biosensor device has as a versatile and specific tool for bacterial detection and quantification, providing a rapid method for the identification of nosocomial pathogens within the clinical requirements of sensitivity for the diagnosis of infections
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