Improvement of Surface Roughness and Hydrophobicity in PETG Parts Manufactured via Fused Deposition Modeling (FDM): An Application in 3D Printed Self–Cleaning Parts

The fused deposition modeling (FDM) technique is used today by companies engaged in the fabrication of tra c signs for the manufacture of light-emitting diode LED spotlights. In this sector, the surface properties of the elements used (surface finish, hydrophobic features) are decisive because surfaces that retain little dirt and favor self–cleaning behavior are needed. A design of experiments (L27) with five factors and three levels has been carried out. The factors studied were: Layer height (LH), print temperature (T), print speed (PS), print acceleration (PA), and flow rate (F). Polyethylene terephthalate glycol (PETG) specimens of 25.0 25.0 2.4 mm have been printed and, in each of them, the surface roughness (Ra,0, Ra,90), sliding angle (SA0, SA90), and contact angle (CA0, CA90) in both perpendicular directions have been measured. Taguchi and ANOVA analysis shows that the most influential variables in this case are printing acceleration for Ra, 0 (p–value = 0.052) and for SA0 (p–value = 0.051) and flow rate for Ra, 90 (p–value = 0.001) and for SA90 (p–value = 0.012). Although the ANOVA results for the contact angle are not significant, specimen 8 (PA = 1500 mm/s2 and flow rate F = 110%) and specimen 10 (PA =1500 mm/s2 and F = 100%) have reached contact angle values above or near the limit value for hydrophobia, respectively

Decision Tree Methods for Predicting Surface Roughness in Fused Deposition Modeling Parts

3D printing using fused deposition modeling (FDM) includes a multitude of control parameters. It is difficult to predict a priori what surface finish will be achieved when certain values are set for these parameters. The objective of this work is to compare the models generated by decision tree algorithms (C4.5, random forest, and random tree) and to analyze which makes the best prediction of the surface roughness in polyethylene terephthalate glycol (PETG) parts printed in 3D using the FDM technique. The models have been created using a dataset of 27 instances with the following attributes: layer height, extrusion temperature, print speed, print acceleration, and flow rate. In addition, a dataset has been created to evaluate the models, consisting of 15 additional instances. The models generated by the random tree algorithm achieve the best results for predicting the surface roughness in FDM parts

Designing conservation strategies to preserve the genetic diversity of Astragalus edulis Bunge, an endangered species from western Mediterranean region

[EN] Astragalus edulis (Fabaceae) is an endangered annual species from the western Mediterranean region that colonized the SE Iberian Peninsula, NE and SW Morocco, and the easternmost Macaronesian islands (Lanzarote and Fuerteventura). Although in Spain some conservation measures have been adopted, it is still necessary to develop an appropriate management plan to preserve genetic diversity across the entire distribution area of the species. Our main objective was to use population genetics as well as ecological and phylogeographic data to select Relevant Genetic Units for Conservation (RGUCs) as the first step in designing conservation plans for A. edulis. We identified six RGUCs for in situ conservation, based on estimations of population genetic structure and probabilities of loss of rare alleles. Additionally, further population parameters, i.e. occupation area, population size, vulnerability, legal status of the population areas, and the historical haplotype distribution, were considered in order to establish which populations deserve conservation priority. Three populations from the Iberian Peninsula, two from Morocco, and one from the Canary Islands represent the total genetic diversity of the species and the rarest allelic variation. Ex situ conservation is recommended to complement the preservation of A. edulis, given that effective in situ population protection is not feasible in all cases. The consideration of complementary phylogeographic and ecological data is useful for management efforts to preserve the evolutionary potential of the species

Time course of early metabolic changes following diffuse traumatic brain injury in rats as detected by 1H NMR spectroscopy

Experimental models of traumatic brain injury (TBI) provide a useful tool for understanding the cerebral metabolic changes induced by this pathological condition. Here, we report on the time course of changes in cerebral metabolites after TBI and its correlation with early brain morphological changes using a combination of high-resolution proton magnetic resonance spectroscopy ( 1H MRS) and magnetic resonance imaging (MRI). Adult male Sprague-Dawley rats were subjected to closed head impact and examined by MRI at 1, 9, 24, 48, and and 72 h after the injury. Extracts from funnel frozen rat brains were then obtained and analyzed quantitatively by high-resolution 1H MRS. Finally, statistical multivariate analysis was carried out to identify the combination of cerebral metabolites that best described the time evolution of diffuse TBI. The temporal changes observed in the concentration of cerebral metabolites followed three different patterns. The first pattern included taurine, threonine, and glycine, with concentrations peaking 24 h after the injury. The second pattern included glutamate, GABA, and alanine, with concentrations remaining elevated between 24 and 48 h post-injury. The third one involved creatine-phosphocreatine, N-acetylaspartate, and myo-inositol, with concentrations peaking 48 h after the injury. A multivariate stepwise discriminant analysis revealed that the combination of the organic osmolytes taurine and myo-inositol allowed optimal discrimination among the different time groups. Our findings suggest that the profile of some specific brain molecules that play a role as organic osmolytes can be used to follow-up the progression of the early diffuse brain edema response induced by TBI. © Mary Ann Liebert, Inc.This work was partly supported by Spanish Ministry of Education and Science (grants SAF 2001-224 and SAF 2004-03197 to J.M.R. and S.C.) and by Spanish Ministry of Health (grants FISss C03/08, C03/10, and G03/155 to J.M.R. and S.C.).Peer Reviewe

Cambios en los parámetros fisiológicos por diarrea neonatal en crías de alpaca

Alpacas in the pre-weaning stage often present neonatal diarrhoea, usually of infectious type, causing high mortality. This study determined the physiological parameters and their changes in animals with diarrhoea. In total, 79 neonate alpacas less than 60 days of age from Pasco and Junín regions, Peru, were used. Of them, 60 had clinical diarrhoea lasting 1 to 3 days, and 19 were healthy (controls). Heart and respiratory rate, peripheral capillary oxygen saturation, body temperature, capillary refill time, and mucous color were determined. A significant increase in heart rate in crias with diarrhea compared to healthy ones was found (p<0.05). Besides, no differences in other physiological parameters between diseased and apparently healthy offspring was found.Las crías de alpaca en la etapa pre-destete cursan con frecuencia con cuadros diarreicos, por lo general de tipo infeccioso, causantes de alta mortalidad. El presente estudio determinó los parámetros fisiológicos y sus cambios en animales con diarrea. Se utilizaron 79 alpacas neonatas menores de 60 días de edad de las zonas de Pasco y Junín, Perú. De ellas, 60 cursaban con cuadros de diarrea entre 1 a 3 días y 19 estaban sanas (controles). Se determinó la frecuencia cardiaca y respiratoria, saturación de la sangre por la presión parcial de oxígeno, temperatura corporal, tiempo de llenado capilar y coloración de las mucosas. Se encontró un aumento significativo de la frecuencia cardiaca (p<0.05) en crías con diarrea en comparación a las sanas, no habiendo diferencias en los demás parámetros fisiológicos entre crías enfermas y aparentemente sanas

Estudios mediáticos y fenómenos migratorios: una revisión sistemática de la literatura desde 2011 hasta 2021

Hacía falta un estado del arte que describiera los principales enfoques, resultados, métodos y teorías de la investigación académica en comunicación sobre el fenómeno migratorio durante la última década. Este análisis bibliométrico de 196 artículos en 37 revistas mayoritariamente escritas en español identificó las publicaciones principales en comunicación que han aportado al entendimiento de las migraciones. Los resultados de esta revisión de la literatura muestran que quienes trabajan en los medios atribuyen las fallas de su oficio a la falta de preparación y a la ausencia de manuales deontológicos; que la calidad de los productos mediáticos sobre la migración tiende a ser pobre; y que la literatura sobre las audiencias documenta los efectos de los medios y la percepción de los públicos receptores de migración. Esos hallazgos sugieren que existe un sesgo académico hacia los fenómenos migratorios latinoamericanos desde perspectivas interseccionales; que hacen falta acercamientos etnográficos a los procesos de creación mediática; que la investigación sobre los productos resulta repetitiva; y que, mientras los estudios sobre las audiencias europeas abundan, los de públicos migrantes escasean. La discusión invita a comprobar esas hipótesis y a incluir más voces latinoamericanas en la conversación global sobre las migraciones

The evaluation of sports performance in Sports Psychology: A systematic review

La presente revisión bibliográfica sistemática tiene como objetivo identificar, describir y sintetizar cómo se ha estudiado el rendimiento deportivo en los artículos empíricos que incluyen variables psicológicas. Se indagó en siete buscadores académicos analizando las características de las revistas, artículos, y diseños implementados. Además, se clasificó las disciplinas deportivas y las medidas de rendimiento deportivo para describir su implicación. Se comprende el rendimiento deportivo como un término polisémico y principalmente sensible a disciplina deportiva siendo necesario un consenso para su operacionalización y avanzar en la comparación y replicación de los estudios empíricos.This systematic literature review aims to identify, describe and synthesize how sports performance has been studied in empirical articles that include psychological variables. It was investigated in seven academic search engines analyzing the characteristics of the magazines, articles, and designs implemented. In addition, sports disciplines and sports performance measures were classified to describe their involvement. Sports performance is understood as a polysemic term and mainly sensitive to sports discipline, a consensus being necessary for its operationalization and advancing in the comparison and replication of empirical studies.Fil: Ursino, Damian Javier. Universidad de Buenos Aires. Facultad de Psicología; ArgentinaFil: Abal, Facundo Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Psicología; ArgentinaFil: Cirami, Lautaro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Psicología; ArgentinaFil: Barrios, Raul M.. Universidad de Buenos Aires. Facultad de Psicología; Argentin

Influencia de la fertilización nitrogenada sobre las concentraciones de K+, Mg2+ y Ca2+ y sus bioindicadores en raíces y hojas de plantas de judía

The pyruvate kinase (PK) and ATPase activities taking part in nitrogen (N) assimilation is essential for the growth and development of plants. Studies on the kinetics of these enzymes reveal that its activities are dependent of the cofactors K+, Ca2+, and Mg2+. Therefore, the objective of the present work was to determine the effect of different doses of N on enzymatic activities of ATPase and PK as potentials biochemical indicators of the levels of K+, Mg2+, and Ca2+ in the roots and leaves of green bean plants. The N was applied to the nutrient solution as NH4NO3 at the following rates: 1.5, 3.0, 6.0, 12.0, 18.0, and 24.0 mM of N. These results indicate that deficient conditions of N (N1 and N2) were characterized by the lowest accumulation of K+, Mg2+ and Ca2+ in both total and soluble forms, and also minimum activities of PK and ATPase induced by K+, Mg2+ and Ca2+, with respect to the activity of basal PK and ATPase; this could mean near optimum conditions for these cations. On the contrary, high-N treatments (N4, N5 and N6) were characterized by presenting decreasing concentrations of total and soluble K+, Mg2+ and Ca2+ in roots and leaves of green bean plants; however, the activities of PK and ATPase induced with K+, Mg2+ and Ca2+ were increased reaching their maximum activity with respect to basal PK and ATPase, both enzymes reflecting the level of cations in roots and leaves, hence being considered as good physiological bioindicators of these cations.Las actividades piruvato kinasa (PK) y ATPasa participan en la asimilación de nitrógeno (N), la cual es esencial para el crecimiento y desarrollo de las plantas. Estudios sobre cinéticas de estas enzimas revelan que sus actividades son dependientes de los cofactores K+, Ca2+ y Mg2+. Por lo tanto, el objetivo del presente trabajo fue determinar el efecto de diferentes dosis de N sobre las actividades de la ATPasa y PK como posibles bioindicadores de los niveles de K+, Mg2+ y Ca2+ en raíces y hojas de plantas de judía (Phaseolus vulgaris L. cv. Strike). Se aplicó N a la solución nutritiva como NH4NO3 en las siguientes dosis: N1=1,5 mM, N2=3,0 mM, N3=6,0 mM, N4=12,0 mM, N5=18,0 mM y N6=24,0 mM. Los resultados indican que bajo condiciones deficientes de N (N1 y N2), las plantas presentaron menor acumulación de K+, Mg2+ y Ca2+ en su forma total y soluble, así como mínimas actividades PK y ATPasa inducidas por K+, Mg2+ y Ca2+ respecto a la actividad PK y ATPasa basal; lo cual indica condiciones cercanas a las óptimas de estos cationes. Por el contrario, en los tratamientos elevados de N (N4, N5 y N6) las plantas presentaron concentraciones decrecientes de K+, Mg2+ y Ca2+ total y soluble tanto en raíces como en hojas; sin embargo, las actividades PK y ATPasa inducidas con K+, Mg2+ y Ca2+ se incrementaron alcanzando sus máximas actividades con respecto a la PK y ATPasa basal, lo que indica una mayor necesidad fisiológica de estos cationes en los tratamientos elevados de N. Finalmente, la actividad ATPasa basal y la inducida con K+, Mg2+ y Ca2+ se comportaron de forma similar a la actividad PK, lo que refleja el nivel de cationes en raíces y en hojas, por lo que se consideran buenos bioindicadores fisiológicos de estos cationes