La evaluación del aprendizaje en la universidad según la experiencia de los estudiantes

En las últimas décadas ha tomado fuerza un modo de entender la evaluación como instrumento para la mejora del aprendizaje. Exploramos mediante métodos de encuesta si esta concepción se corresponde con la realidad de la evaluación en las universidades españolas. Las experiencias de 4580 alumnos de 9 universidades y 54 titulaciones muestran que la evaluación llevada a la práctica corresponde mayoritariamente a un modelo tradicional, con carencias evidentes en cuanto a la participación del alumnado y la retroalimentación proporcionada. Reflexionamos sobre la relevancia de estas carencias y se apuntan vías para mejorar la evaluación del aprendizaje en la universidad

Long-term effects of the consumption of Stevia rebaudiana (Magnoliopsida, Asteraceae) on fertility mice’s

Este trabajo fue realizado con el objetivo de conocer los efectos a largo plazo del consumo de extractos acuosos de hojas de Stevia rebaudiana (Bertoni) sobre el número de crías, la micromorfología de los órganos genitales, niveles de testosterona y estrógeno totales, de ratones albinos. Se Trabajó con cuatro grupos de ratones, cada grupo estuvo conformado por seis macho y seis hembras. Un grupo control (C) y tres tratamientos, el primero consumió alimento y agua mientras que los grupos tratamientos consumieron el mismo alimento pero en vez del agua un extracto de S. rebaudiana a concentraciones de (g/Kg) 3,75 (I), 7,5 (II) y 15 (III), por 120 días. Las crías fueron contadas y pesadas después de cada nacimiento, la histología de los órganos genitales entre los grupos fue comparada, se midió los niveles séricos de testosterona y estrógeno total por inmunoquimio-luminiscencia, así mismo se observó el comportamiento sexual. Los niveles de testosterona total (ng/mL) fueron significativamente diferentes entre los grupos (C= 1,02±0,03; I= 1,12±0,01; II= 1,16±0,02; III= 1,21±0,01). Así mismo los niveles de estrógeno total (pg/mL) también mostraron diferencias significativas (C= 20,77±7,22; I= 30,58±2,07; II= 33,08±3,45; III= 43,58±10,3). Sin embargo no se observaron diferencias significativas entre los pesos (g) de los úteros, trompas y ovarios (C= 0,065±0,005; I= 0,058±0,007; II= 0,058±0,007; III= 0,056±0,005). El peso (g) de testículos mostró diferencias significativas solamente con el tratamiento III (C= 0,153±0,005; I= 0,155±0,005; II= 0,145±0,005; III= 0,110±0,008). No se detectaron diferencias histológicas en los órganos genitales del grupo control y de los grupos tratamientos. La libido en los ratones machos tratados con SrB estuvo aumentada. Finalmente, el peso de las crías (g) fue mayor y estadísticamente diferente en los grupos II y III (C= 7,53±0,26; I= 7,86±0,47; II= 9,37±0,66; III= 9,35±0,45), mientras que el número de crías fue menor y significativamente diferente para los tratamientos II y III (C= 10,83±0,75; I= 11,83±1,17; II= 8,66±0,52; III= 9,17±0,98). Se concluye que el consumo a largo plazo de SrB no afectó la fertilidad de los ratones pero sí disminuyó notablemente el peso y el tamaño de los testículos. Sin embargo los niveles de testosterona y estrógenos aumentaron notablemente.The objective of this work was to determine the long-term effects of consuming aqueous extracts of Stevia rebaudiana (Bertoni) leaves on the number of offspring, microscopic morphology of genitalia, and levels of testosterone and estrogens in albino mice. We studied four groups of mice, each consisting of 6 males and 6 females. One group was the control (C) and received food and plain water. Three groups received treatment of food and water with extract of S. rebaudiana at concentrations of (g/Kg) 3,75g (I), 7,5 (II) and 15 (III) for a period of 120 days. The offspring were counted and the histology of genitalia among the groups was compared. Serum levels of total testosterone and estrogens were measured by immunoassay and sexual behaviour was observed. Levels of total testosterone (ng/mL) were significantly different between groups (C= 1,02±0,03; I=1,12±0,01; II= 1,16±0,02; III= 1,21±0,01). Likewise were also significantly different the levels of total estrogens (pg/mL) (C= 20,77±7,22; I= 30,58±2,07; II= 33,08±3,45; III= 43,58±10,3). But no significant differences were observed between the weights (g) of the uterus, tubes and ovaries in group (C= 0,065±0,005; I= 0,058±0,007, II= 0,058±0,007; III= 0,056±0,005). The weight (g) of the testicles showed significant differences only with the treatment III (C= 0,153±0,005; I= 0,155±0,005, II= 0,145±0,005; III= 0,110±0,008). Histological differences in the genital organs between control group and the treatment groups were not detected. Libido in male mice treated with SrB was increased. The weight of the offspring (g) was higher and statistically different in groups II and III (C= 7,53±0,26; I= 7,86±0,47; II= 9,37±0,66; III= 9,35±0,45). The number of offspring was lower and significantly different for treatments II and III (C= 10,83±0,75; I= 11,83±1,17; II= 8,66±0,52; III= 9,17±0,98). We conclude that consumption of SrB does not affect fertility in mice. However, SrB consumption is associated with markedly diminished weight of the testicles accompanied by increased testosterone and estrogens levels

Shared Preferences by Predators and Females for Male Ornaments in Swordtails

Sexually dimorphic traits in many mate recognition systems have evolved in response to preexisting female biases. These biases are often quite general in form and are likely to be shared by predators, thereby imposing a cost on male trait expression. The Mexican tetra Astyanax mexicanus (Pisces: Characidae), a visual predator of swordtail fishes, exhibits the same visual preferences for male body size morphs as do females. Furthermore, tetras in populations where swordtails are absent prefer males with sword ornaments over males with swords removed. The predator preference is thus likely to have arisen prior to contact with fishes beating the ornaments, as has also been suggested for mating preferences for swords.Waller Creek Working Grou

Potential control of forest diseases by solutions of chitosan oligomers, propolis and nanosilver

There is a growing necessity to replace chemical agents with ecofriendly materials, arising from the impact on the environment and/or human health, which calls for the design of new broad-spectrum fungicides. In this work, chitosan oligomers (COs), propolis (Ps) and silver nanoparticles (AgNPs) mixtures in solution were assessed to control the growth of different phytopathogenic fungi and oomycetes in vitro. Binary solutions of COs-Ps and COs-AgNPs evinced the highest antifungal effect against Fusarium circinatum and Diplodia pinea fungi, respectively, with a ca. 80% reduction in their mycelial growth. The COs solution by itself also proved to be greatly effective against Gremmeniella abietina, Cryphonectria parasitica and Heterobasidion annosum fungi, causing a reduction of 78%, 86% and 93% in their growth rate, respectively. Likewise, COs also attained a 100% growth inhibition on the oomycete Phytophthora cambivora. On the other hand, Ps inhibited totally the growth of Phytophthora ×alni and Phytophthora plurivora. The application of AgNPs reduced the mycelial growth of F. circinatum and D. pinea. However, the AgNPs in some binary and ternary mixtures had a counter-productive effect on the anti-fungal/oomycete activity. In spite of the fact that the anti-fungal/oomycete activity of the different treatments showed a dependence on the particular type of microorganism, these solutions based on natural compounds can be deemed as a promising tool for control of tree diseases

The best fit for the observed galaxy Counts-in-Cell distribution function

The Sloan Digital Sky Survey (SDSS) is the first dense redshift survey encompassing a volume large enough to find the best analytic probability density function that fits the galaxy Counts-in-Cells distribution $f_V(N)$, the frequency distribution of galaxy counts in a volume $V$. Different analytic functions have been previously proposed that can account for some of the observed features of the observed frequency counts, but fail to provide an overall good fit to this important statistical descriptor of the galaxy large-scale distribution. Our goal is to find the probability density function that better fits the observed Counts-in-Cells distribution $f_V(N)$. We have made a systematic study of this function applied to several samples drawn from the SDSS. We show the effective ways to deal with incompleteness of the sample (masked data) in the calculation of $f_V(N)$. We use LasDamas simulations to estimate the errors in the calculation. We test four different distribution functions to find the best fit: the Gravitational Quasi-Equilibrium distribution, the Negative Binomial Distribution, the Log Normal distribution and the Log Normal Distribution including a bias parameter. In the two latter cases, we apply a shot-noise correction to the distributions assuming the local Poisson model. We show that the best fit for the Counts-in-Cells distribution function is provided by the Negative Binomial distribution. In addition, at large scales the Log Normal distribution modified with the inclusion of the bias term also performs a satisfactory fit of the empirical values of $f_V(N)$. Our results demonstrate that the inclusion of a bias term in the Log Normal distribution is necessary to fit the observed galaxy Count-in-Cells distribution function.Comment: 12 pages, 16 figures. Accepted for publication in Astronomy & Astrophysic

Ethanol-Induced Oxidative Stress Modifies Inflammation and Angiogenesis Biomarkers in Retinal Pigment Epithelial Cells (ARPE-19): Role of CYP2E1 and its Inhibition by Antioxidants

The retinal pigment epithelium (RPE) plays a key role in retinal health, being essential for the protection against reactive oxygen species (ROS). Nevertheless, excessive oxidative stress can induce RPE dysfunction, promoting visual loss. Our aim is to clarify the possible implication of CYP2E1 in ethanol (EtOH)-induced oxidative stress in RPE alterations. Despite the increase in the levels of ROS, measured by fluorescence probes, the RPE cells exposed to the lowest EtOH concentrations were able to maintain cell survival, measured by the Cell Proliferation Kit II (XTT). However, EtOH-induced oxidative stress modified inflammation and angiogenesis biomarkers, analyzed by proteome array, ELISA, qPCR and Western blot. The highest EtOH concentration used stimulated a large increase in ROS levels, upregulating the cytochrome P450-2E1 (CYP2E1) and promoting cell death. The use of antioxidants such as N-acetylcysteine (NAC) and diallyl sulfide (DAS), which is also a CYP2E1 inhibitor, reverted cell death and oxidative stress, modulating also the upstream angiogenesis and inflammation regulators. Because oxidative stress plays a central role in most frequent ocular diseases, the results herein support the proposal that CYP2E1 upregulation could aggravate retinal degeneration, especially in those patients with high baseline oxidative stress levels due to their ocular pathology and should be considered as a risk factor.LVG was recipient of a pre-doctoral fellowship (EDUCV-PRE-2015-006). Financial support by grant #94/2016 from the PROMETEO program from the Generalitat Valenciana, Valencia, Spain, to FJR

Deciphering Main Climate and Edaphic Components Driving Oat Adaptation to Mediterranean Environments

Oat, Avena sativa, is an important crop traditionally grown in cool-temperate regions. However, its cultivated area in the Mediterranean rim steadily increased during the last 20 years due to its good adaptation to a wide range of soils. Nevertheless, under Mediterranean cultivation conditions, oats have to face high temperatures and drought episodes that reduce its yield as compared with northern regions. Therefore, oat crop needs to be improved for adaptation to Mediterranean environments. In this work, we investigated the influence of climatic and edaphic variables on a collection of 709 Mediterranean landraces and cultivars growing under Mediterranean conditions. We performed genotype–environment interaction analysis using heritability-adjusted genotype plus genotype–environment biplot analyses to determine the best performing accessions. Further, their local adaptation to different environmental variables and the partial contribution of climate and edaphic factors to the different agronomic traits was determined through canonical correspondence, redundancy analysis, and variation partitioning. Here, we show that northern bred elite cultivars were not among the best performing accessions in Mediterranean environments, with several landraces outyielding these. While all the best performing cultivars had early flowering, this was not the case for all the best performing landraces, which showed different patterns of adaption to Mediterranean agroclimatic conditions. Thus, higher yielding landraces showed adaptation to moderate to low levels of rain during pre- and postflowering periods and moderate to high temperature and radiation during post-flowering period. This analysis also highlights landraces adapted to more extreme environmental conditions. The study allowed the selection of oat genotypes adapted to different climate and edaphic factors, reducing undesired effect of environmental variables on agronomic traits and highlights the usefulness of variation partitioning for selecting genotypes adapted to specific climate and edaphic conditionsThis work was supported by the grant PID2019-104518RBI00 funded by MCIN/AEI/10.13039/501100011033. FC and LMG-S are holder of a FPI fellowship (BES-2014-071044) and (BES-2017-080152), respectively, from the Spanish Ministry of Economy and Competitiveness. GM-B is holder of a Junta de Andalucia grant for Doctors [DOC_00394]. We thank CRF and USDA for supplying the seed