Liposome formation with wool lipid extracts rich in ceramides

Internal wool lipids (IWLs) are rich in cholesterol, free fatty acids, cholesteryl sulfate, and, mainly, ceramides. The repairing effect of these lipids structured as liposomes was demonstrated by reinforcing the skin-barrier integrity and increasing the water-holding capacity when applied onto the skin. This work was focused on the formation of liposomes with IWLs rich in ceramides, obtained at pilot plant level with organic solvent extraction by using methanol and acetone. The lipid composition of the two extracts was quantitatively analyzed. IWL extracts containing different amounts of sterol sulfate were used to form liposomes at physiologic pH. Vesicle size distribution, polydispersity index, and zeta potential of all liposomes were determined to characterize them and to study their stability. The results obtained showed that IWL extract composition, which was different depending on the extraction methodologies used, greatly influences the characteristics of the liposomes formed. Vesicular size and polydispersity index liposomes were smaller when the extract composition contained a higher proportion of either free fatty acids or sterol sulfate. Moreover, liposome stability was improved when some amount of sterol sulfate was added to the composition of methanol and acetone extracts. This natural mixture with keratinaceous origin could have a special interest for cosmetic or dermopharmaceutical companies.We acknowledge Mr. G. von Knorring for his expert technical assistance. We are also indebted to the DGICYT Program (PPQ 2002-94136-C02-01 and C02-02) for financial support

Chemical compositions of stars in two stellar streams from the Galactic thick disk

We present abundances for 20 elements for stars in two stellar streams identified by Arifyanto & Fuchs (2006, A&A, 449, 533): 18 stars from the Arcturus stream and 26 from a new stream, which we call AF06 stream, both from the Galactic thick disk. Results show both streams are metal-poor and very old (10$-$14 Gyrs) with kinematics and abundances overlapping with the properties of local field thick disk stars. Both streams exhibit a range in metallicity but with relative elemental abundances that are identical to those of thick disk stars of the same metallicity. These results show that neither stream can result from dissolution of an open cluster. It is highly unlikely that either stream represents tidal debris from an accreted satellite galaxy. Both streams most probably owe their origin to dynamical perturbations within the Galaxy.Comment: 10 figures, Accepted for publication in MNRA

Estrategia pedagógica basada en el teatro y el dibujo para promover la construcción de la escritura en los niños y niñas en educación inicial vinculados al programa Ondas de la Institución Educativa Técnico Alfonso López sede la Concordia

Maestría en Educación desde la Diversidad, Facultad de Ciencias Sociales y Humanas.La producción escrita se considera una habilidad lingüística compleja que contempla en la construcción de palabras los siguientes niveles del lenguaje: presilábico, silábico, silábico-alfabético y alfabético. En el ámbito educativo, esta destreza es esencial para el fortalecimiento de las competencias comunicativas. El presente trabajo investigativo de tipo cuantitativo, con diseño pre experimental, busca determinar la efectividad de una estrategia pedagógica basada en el teatro y el dibujo para promover la construcción de la escritura; la población objeto es de 20 estudiantes de educación inicial de la Institución Educativa Técnico Alfonso López (sede Concordia de La Dorada, Caldas), vinculados al programa Ondas de Colciencias. Para conseguir el propósito, se aplicó un pre-test con la finalidad de conocer el nivel de escritura que poseían los estudiantes. Así mismo, se estructuró y desarrolló una estrategia pedagógica basada en el teatro y el dibujo con el objetivo de acrecentar habilidades escriturales enfocadas en las cuatro actividades rectoras, destacando en ellas, habilidades para la literatura, el juego, el arte y la exploración del medio. Finalmente, se usó un pos-test para determinar el proceso evolutivo de construcción de la escritura. El tratamiento estadístico de resultados se analizó con la utilización del programa SPSS. La investigación comprobó que la estrategia propuesta impulsa el tránsito por los niveles de construcción de la escritura de los estudiantes, la cual incrementó de 0 % al 100 % en la escala de niveles de escritura clasificada así por Emilia Ferreiro y Ana Teberosky. La adquisición de esas habilidades permitió a los niños avanzar en la apropiación de elementos básicos y herramientas necesarias para iniciar el proceso de la escritura

Mitochondrial Aging and Metabolism: The Importance of a Good Relationship in the Central Nervous System

The mitochondrial theory of aging suggests that mitochondria have a decrease in production capacity of adenosine triphosphate (ATP). The question may seem trivial, but it becomes more complex when considering that dysfunctional mitochondria can be eliminated by lysosomal digestion and that cell with dysfunctional mitochondria can undergo the process of apoptosis. In organs with regenerative capacity, like the liver, cell proliferation can almost completely hide mitochondrial dysfunction. However, evidence indicates selective damage in mitochondria during aging, and so the mitochondrial aging theory is gaining recognition and respect. There is solid evidence that accumulated DNA damage in mitochondria is a cause directly related to metabolic disorders such as diabetes and degenerative disorders such as Alzheimer’s disease. The central nervous system is particularly susceptible to oxidative damage due to several factors, among which are its high oxygen consumption, its dependence on aerobic carbohydrate metabolism, and its complex composition of membrane lipids. Free radicals are generated at many cell sites, and the mitochondrial respiratory chain is one of the main sources. While many studies have been conducted in experimental animal models, the results are relevant because at least some of their interventions suggest a directing aim at reducing the effects of aging

Missing Features Reconstruction Using a Wasserstein Generative Adversarial Imputation Network

Missing data is one of the most common preprocessing problems. In this paper, we experimentally research the use of generative and non-generative models for feature reconstruction. Variational Autoencoder with Arbitrary Conditioning (VAEAC) and Generative Adversarial Imputation Network (GAIN) were researched as representatives of generative models, while the denoising autoencoder (DAE) represented non-generative models. Performance of the models is compared to traditional methods k-nearest neighbors (k-NN) and Multiple Imputation by Chained Equations (MICE). Moreover, we introduce WGAIN as the Wasserstein modification of GAIN, which turns out to be the best imputation model when the degree of missingness is less than or equal to 30%. Experiments were performed on real-world and artificial datasets with continuous features where different percentages of features, varying from 10% to 50%, were missing. Evaluation of algorithms was done by measuring the accuracy of the classification model previously trained on the uncorrupted dataset. The results show that GAIN and especially WGAIN are the best imputers regardless of the conditions. In general, they outperform or are comparative to MICE, k-NN, DAE, and VAEAC.Comment: Preprint of the conference paper (ICCS 2020), part of the Lecture Notes in Computer Scienc

Aplicación del proceso de jerarquía analítica (AHP) en la selección de tecnología logística

El transporte terrestre es una de las modalidades más utilizadas en el mundo para transportar mercaderías, luego del transporte marítimo, moviéndose anualmente más de 6.000 Tn/km (Banco Mundial, 2019). Por lo tanto, es un motor fundamental en la economía de los países y esto lleva a que exista un gran interés por parte de las empresas transportistas y de los clientes para encontrar formas de optimizar este proceso. En la composición de los costos empresariales, se calcula que el costo total de distribución representa un 7,65%, del cual el costo de transporte es el de mayor incidencia con un 3,34% (Ballou, 2004), por lo tanto, su análisis y optimización son fundamentales para lograr competitividad. En la empresa logística bajo estudio, se cuenta con personal encargado para la carga y selección de la mejor ubicación de las mercaderías dentro de semirremolques, quienes utilizan su experiencia y métodos empíricos para hacer el trabajo. Para esta organización en particular, no está establecido el uso de alguna plataforma digital para la gestión del llenado eficiente de los vehículos de carga. En este trabajo, se abordó, el problema de selección de un sistema computacional logístico para la gestión de la carga y su ubicación eficiente dentro de semirremolques de una empresa paraguaya, importadora y exportadora de mercaderías. Dado que, para la elección del mejor software, especializado para la carga eficiente de móviles con mercaderías, se debe tener en cuenta múltiples criterios, se presenta una propuesta de selección basada en el Proceso de Jerarquía Analítica (Analytical Hierarchy Process, AHP), para comparar los sistemas computacionales para la logística de carga y ubicación de mercaderías. De esta manera, se pudo definir una ponderación de los criterios a evaluar en términos de pesos, de acuerdo con su nivel de importancia, gerencial y operacional, para finalmente tener una elección objetiva y que cumpla con los requerimientos predefinidos. Los sistemas computacionales disponibles son Easy Cargo, Searates, Goodloading y Logen Solutions. Mientras que los criterios analizados fueron funcionalidad, practicidad, precio, idiomas de interfaz, y conectividad con otras plataformas, con ese orden para el valor de las ponderaciones de mayor a menor. Con estas variables, se realizó la jerarquización, construyendo matrices de comparación pareadas para evaluar cada alternativa respecto de cada criterio, como así también, criterio versus criterio. Se realizó un test de consistencia para cada matriz pareada; por un lado, para matrices de comparación entre alternativas criterio por criterio, y para la matriz de comparación criterio versus criterio. Al efectuar el test de consistencia de cada matriz pareada, se determinó que cada Razón de Consistencia (RC) para las matrices de comparación entre alternativas fue menor a 0.09 (9%), cota superior permitida para matrices de orden 4x4 según Aznar y Guijarro (2012). En cuanto a la RC de la matriz de comparación criterio versus criterio, no se sobrepasó la cota superior de 0,1(10%) para matrices de orden 5x5. Se concluye que la metodología propuesta es aceptable, pues permitió la jerarquización y la selección del mejor sistema computacional logístico para carga y ubicación de mercaderías, de acuerdo con los criterios tomados en cuenta. De acuerdo con los resultados de la ponderación final para la elección el mejor sistema es Logen Solutions (0.38). Se propone como trabajo futuro, incrementar el número de opciones de sistemas computacionales, y ahondar en más criterios como costo de mantenimiento, tiempo de capacitación, tiempo de implementación, entre otros.Sociedad Argentina de Informática e Investigación Operativ

The herpetofauna of Hidalgo, Mexico: Composition, distribution, and conservation status

The herpetofauna of Hidalgo, Mexico, is comprised of 203 species, including 42 anurans, 17 caudates, one crocodylian, 137 squamates, and six turtles. Here, the distribution of the herpetofaunal species are catalogued among the four recognized physiographic regions. The total number of species varies from 77 in the Mexican Plateau to 166 in the Sierra Madre Oriental. The individual species occupy from one to four regions (mean = 2.1). About 69% of the Hidalgo herpetofauna is found in only one or two of the four regions, which is of considerable conservation significance. The greatest number of single-region species occupies the Sierra Madre Oriental (25), followed by the Gulf Coastal Lowlands (15), the Trans-Mexican Volcanic Belt (6), and the Mexican Plateau (2). The Coefficient of Biogeographic Resemblance (CBR) indicates that the Sierra Madre Oriental and the Gulf Coastal lowlands share the most species (72), because of their adjacent geographic position and they contain a significant number of generalist species that occur in the Gulf lowlands of Mexico, southern USA, Central America, and/or South America. The two largest geographic regions in Hidalgo by area, Sierra Madre Oriental and Mexican Plateau, reflect opposite patterns in species richness (166 and 77 species, respectively) due to overall differences in the ecological characteristics between them. A similarity dendrogram based on the Unweighted Pair Group Method with Arithmetic Averages (UPGMA) depicts two distinct clusters, one between the Sierra Madre Oriental and Gulf Coastal Lowlands and the other between the Mexican Plateau and Trans-Mexican Volcanic Belt. The former cluster reflects the two regions sharing a substantial number of herpetofaunal species that occur on the Gulf lowlands of North America and Central America, as well as a few that enter South America. The second cluster is due to the two montane regions being adjacent to one another and their ecological similarities. With respect to the distributional categories, the largest number of species is that of the country endemics (104 of 203), followed by non-endemics (92), state endemics (four), and non-natives (three). The principal environmental threats to the Hidalgo herpetofauna are deforestation, livestock, roads, pollution of water sources, cultural factors, and diseases. The conservation status of each native species was assessed by means of the SEMARNAT (NOM-059), IUCN, and EVS systems, of which the EVS system was the most useful. The Relative Herpetofaunal Priority (RHP) method was also used to designate the rank order significance of the physiographic regions and the highest values were found for the Sierra Madre Oriental. Most of the five protected areas in Hidalgo are located in the Trans-Mexican Volcanic Belt, which is only the second most important region from a conservation perspective. In addition, only 78 of the 200 native species found in Hidalgo are recorded in total from the five protected areas. Finally, a set of conclusions and recommendations are offered for the future protection of the Hidalgo herpetofauna

Multiple Imputation Ensembles (MIE) for dealing with missing data

Missing data is a significant issue in many real-world datasets, yet there are no robust methods for dealing with it appropriately. In this paper, we propose a robust approach to dealing with missing data in classification problems: Multiple Imputation Ensembles (MIE). Our method integrates two approaches: multiple imputation and ensemble methods and compares two types of ensembles: bagging and stacking. We also propose a robust experimental set-up using 20 benchmark datasets from the UCI machine learning repository. For each dataset, we introduce increasing amounts of data Missing Completely at Random. Firstly, we use a number of single/multiple imputation methods to recover the missing values and then ensemble a number of different classifiers built on the imputed data. We assess the quality of the imputation by using dissimilarity measures. We also evaluate the MIE performance by comparing classification accuracy on the complete and imputed data. Furthermore, we use the accuracy of simple imputation as a benchmark for comparison. We find that our proposed approach combining multiple imputation with ensemble techniques outperform others, particularly as missing data increases