1,210 research outputs found

    Fusarium oxysporum Casein Kinase 1, a Negative Regulator of the Plasma Membrane H+-ATPase Pma1, Is Required for Development and Pathogenicity

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    Like many hemibiotrophic plant pathogens, the root-infecting vascular wilt fungus Fusarium oxysporum induces an increase in the pH of the surrounding host tissue. How alkalinization promotes fungal infection is not fully understood, but recent studies point towards the role of cytosolic pH (pHc) and mitogen-activated protein kinase (MAPK) signaling. In fungi, pHc is mainly controlled by the essential plasma membrane H+-ATPase Pma1. Here we created mutants of F. oxysporum lacking casein kinase 1 (Ck1), a known negative regulator of Pma1. We found that the ck1Δ mutants have constitutively high Pma1 activity and exhibit reduced alkalinization of the surrounding medium as well as decreased hyphal growth and conidiation. Importantly, the ck1Δ mutants exhibit defects in hyphal chemotropism towards plant roots and in pathogenicity on tomato plants. Thus, Ck1 is a key regulator of the development and virulence of F. oxysporum

    Towards Guidelines for Assessing Qualities of Machine Learning Systems

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    Nowadays, systems containing components based on machine learning (ML) methods are becoming more widespread. In order to ensure the intended behavior of a software system, there are standards that define necessary quality aspects of the system and its components (such as ISO/IEC 25010). Due to the different nature of ML, we have to adjust quality aspects or add additional ones (such as trustworthiness) and be very precise about which aspect is really relevant for which object of interest (such as completeness of training data), and how to objectively assess adherence to quality requirements. In this article, we present the construction of a quality model (i.e., evaluation objects, quality aspects, and metrics) for an ML system based on an industrial use case. This quality model enables practitioners to specify and assess quality requirements for such kinds of ML systems objectively. In the future, we want to learn how the term quality differs between different types of ML systems and come up with general guidelines for specifying and assessing qualities of ML systems.Comment: Has been accepted at the 13th International Conference on the Quality of Information and Communications Technology QUATIC2020 (https://2020.quatic.org/). QUATIC 2020 proceedings will be included in a volume of Springer CCIS Series (Communications in Computer and Information Science

    Influence of Tillage and Liming on N2O emission from a rainfed crop

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    Nitrous oxide (N2O) is the main greenhouse gas (GHG) produced by agricultural soils due to microbial processes. The application of N fertilizers is associated with an increase of N2O losses. However, it is possible to mitigate these emissions by the introduction of adequate management practices (Snyder et al., 2009). Soil conservation practices (i.e.no tillage, NT) have recently become widespread because they promote several positive effects (increases in soil organic carbonand soil fertility, reduction of soil erosion, etc). In terms of GHG emissions, there is no consensus in the literature on the effects of tillage on N2O. Several studies found that NT can produce greater (Baggs et al., 2003), lower (Malhi et al., 2006) or similar (Grandey et al., 2006) N2O emissions compared to traditional tillage (TT). This large uncertainty is associated with the duration of tillage practices and climatic variability. Liming is widely use to solve problems of soil acidity (Al toxicity, yield penalties, etc). Several studies show a decrease in N2O emissions with liming (Barton et al., 2013) whereas no significant effects or increases were observed in others (Galbally et al., 2010). The aim of this work was to evaluate the effects of tillage (NT vs TT) and liming application or not of Ca-amendment) on N2O emissions from an acid soil during a rainfed crop

    Sesame meal as the first protein source in piglet starter diets and advantages of a phytase: a digestive study

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    Soybean meal (SBM) is the protein source that is used most in feeding piglets, but its high price has prompted a search for alternatives. One option is sesame meal (SM), a by-product of sesame oil. This study evaluated the effects of SM and phytase on the intestinal morphology, total trypsin activity (TTA) and specific trypsin activity (STA), apparent ileal digestibility (AID) of amino acids (AAs), and apparent total tract digestibility (ATTD) of phosphorus (P), calcium (Ca), and energy (E) in weaned piglets. Twenty piglets weaned at 17 days old were placed in metabolic cages in a temperature-controlled room. When the piglets were 21 days old, cannulas were fitted at the terminal ileum. From the fourth day after surgery, piglets received the experimental treatments for nine days, namely an SM or SBM diet, each with or without phytase. The protein source or phytase did not affect villus height, crypt depth, or TTA. However, phytase increased STA. The AID of dry matter (DM), E, crude protein (CP), and AA was similar among treatments, except for arginine, which was more digestible in the SM diets (85.8) than in the SBM ones (81.6). The ATTD of DM and E was higher in the SM than in the SBM diets. Phytase increased the ATTD of Ca (22.7 %) and P (27.9 %). The findings showed that SM can be used as a protein source for piglets and that its consumption increases arginine intake. The addition of phytase to the diet increases the ATTD of P and Ca.Keywords: Amino acids digestibility, arginine, piglets weaning, phosphorus digestibilit

    Diversidad de árboles y arbustos en fragmentos de bosque seco tropical en río Hato, Panamá

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    The floristic composition of trees and shrubs in tropical dry forest fragments in Río Hato, Panama was studied. We established 61 plots of 100 m2 distributed randomly, totaling 0.61 hectares. In each sampling unit we measured all individuals above 5.0 cm DAP. We found a total of 52 tree species represented in 25 families, of which Fabaceae, Burseraceae, Myrtaceae and Rubiaceae account for 35% of the species. The species Sloanea terniflora was found in more than 60.6% of the quadrants. This species also proved to be the one with the highest relative dominance (23%) followed by Anacardium excelsum, with only 15 individuals of large diameters, showing a relative dominance of 10%. Mean diversity indices revealed intermediate values (Shannon index 3.13). While the number of tree species is relatively low when compared to other tropical dry forests in the region, the fragments in Río Hato preserve floristic elements of ecological importance for the conservation of tropical dry forests. Garcinia madruno, the most abundant species is a key species in fruit production for wildlife and other species have been overexploited as timber resources, e.g., Manilkara sapota and Copaifera aromatica. Establishing conservation strategies to safeguard these fragments as a source of tropical dry forest species and as wildlife refuges should be a priority for Panama.En fragmentos de bosque seco tropical en Río Hato, Panamá, estudiamos la composición florística según los árboles y arbustos. Establecimos 61 parcelas de 100 m2 distribuidas de forma aleatoria, totalizando 0.61 hectáreas. En cada unidad de muestreo medimos todos los individuos presentes con un DAP >5.0 cm. Encontramos un total de 52 especies de árboles representadas en veinticinco familias, de las cuales Fabaceae, Burseraceae, Myrtaceae y Rubiaceae aportan mayor número de especies (~35%). La especie Sloanea terniflora (Sessé & Moç. ex DC.) Standl se encontró en más del 60.6% de los cuadrantes estudiados y resultó además ser la especie con mayor dominancia relativa (23%), seguida de Anacardium excelsum (Bertero & Balb. ex Kunth) Skeels, que con solo quince individuos de grandes diámetros presentó una dominancia relativa del 10%. La diversidad promedio reveló índices intermedios (3.13 índice de Shannon). A pesar del bajo número de especies en comparación con otros BS-T de la región, los fragmentos en Río Hato conservan elementos florísticos de importancia ecológica y para la conservación de los bosques secos. Garcinia madruno (Kunth) Hammel, una de las especies más abundante es clave en la producción de frutos para la fauna. Otras especies de importancia son Manilkara sapota (L.) P. Royen y Copaifera aromatica Dwyer, las cuales aún son utilizadas como recurso maderero. Es prioritario para Panamá establecer estrategias de conservación que salvaguarden estos fragmentos como fuente de especies del bosque seco tropical y refugio para la vida silvestre.

    High quality optically active and integrable EuOOH films prepared by pulsed laser deposition

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    Rare-earth (RE)-Oxygen-Hydrogen compounds are versatile materials whose composition and properties can be significantly varied by changing the relative O and H contents. Among them hydrides and oxyhydrides have been thoroughly investigated due to its photochromic properties. Instead, research of RE-hydroxides and oxyhydroxides (RE-OH and RE-OOH) is scarce although they show promising properties as light emitters. However, their use and integration in solid state devices have been hindered so far because their usual chemical synthesis routes yield materials in bulk or powder configurations. In this work we demonstrate a physical deposition route based on pulsed laser deposition that results in the unprecedented preparation of high-quality Eu oxyhydroxide (EuOOH) thin films. The synthetized EuOOH films show a well-defined monoclinic structure, are optically active and show a robust red emission related to the intra-f transitions of the Eu3+ ions. The excellent quality of these crystalline films has allowed us to obtain relevant properties of the monoclinic EuOOH phase not previously reported such as its refractive index and its Raman spectrum, including the identification of the characteristic phonon modes. These novel EuOOH films have been prepared both on Si and fused silica substrates, and thus are ready for potential integration in solid state optoelectronic components and devicesThis work was funded by the Spanish Research Agency (AEI, Ministry of Research and Innovation) and the European Regional Development Fund (ERDF) under grants RTI2018-096498-B-I00, RTI2018-101020-B-I00, RTI2018-096918-B-C41 and PID2021-123190OB-I00; by the CSIC (PIE-202050E195 and project 2021AEP128IO); by the Regional Government of Madrid through TECHNOFUSION(III)CM ´ (S2018/EMT-4437); and by Comunidad de Madrid (Spain) multiannual agreement with UC3M, “Excelencia para el Profesorado Universitario” (EPUC3M14) - Fifth regional research plan 2016-2020. The work of A. Cano was partially supported by the Autonomous Community of Madrid and the European Social Fund (PEJD-2019-PRE/TIC-16082

    Influence of seat-belt use on the severity of injury in traffic accidents

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    ABSTRACT: Background: About 1.35 million people died in traffic accidents around the world in 2018, make this type of accidents the 8th cause of death in the world. Particularly, in Spain, there were 204,596 traffic accidents during 2016 and 2017, out of which 349,810 drivers were injured. The objective of this study was to understand to what extent seat belt non-use and human factors contribute to drivers injury severity. Methodology: The results are based on the information and 2016-17 data provided by the Spain national traffic department "Dirección General de Tráfico" (DGT). The discretization model and Bayesian Networks were developed based on important variables from the literature. These variables were classified as; human factor, demographic factor, conditioning factor and seat belt use. Results: The results showed that failure to wear the seat belt by drivers are likely to increase the risk of fatal and sever injury significantly. Moreover, distraction and road type road can contribute to the accident severity

    Gender gap in STEM: a cross-sectional study of primary school students’ self-perception and test anxiety in mathematics

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    Contribution: Significant gender differences are observed on primary school students’ perception of self-efficacy and test anxiety in mathematics. Girls perceive themselves to be significantly worse than boys in mathematics and report higher test anxiety toward mathematics exams. Gender differences in self-efficacy become more pronounced as students grow up, and test anxiety increases for all students. However, the present study shows that teachers’ do not perceive differences in self-efficacy in mathematics between boys and girls. Background: The low presence of women in science, technology, engineering, and mathematics (STEM) might be explained by the attitude of young students toward mathematics. Different studies show that girls are less interested in STEM areas than boys during secondary school. A study on the reasons for this fact pointed out that the early years of education can provide a relevant insight to reverse the situation. Research Questions: Is there any age-dependent gender difference in primary school students in aspects related to mathematics? Are teachers aware of students’ perceptions? Methodology: This work presents a study of over 2000 primary school students (6–12 years old) and 200 teachers in Aragón (Spain). The study consists of a survey on aspects that influence the experience of female and male students with mathematics and Spanish language for comparison purposes and teacher’s awareness of students’ perception. Findings: The present study shows that during primary school, girls are more likely to experiment a negative attitude toward mathematics than boys as they grow up, and teachers may not perceive girls’ situation. La baja presencia de mujeres en ciencia, tecnología, la ingeniería y las matemáticas (STEM) podrían explicarse por la actitud de las niños y niñas hacia las matemáticas. Diferentes estudios muestran que las niñas están menos interesadas en las áreas STEM que niños cuando cursan educación secundaria. Además, un estudio sobre los motivos para este hecho señaló que los primeros años de educación podrían proporcionar una visión relevante para revertir la situación. Por ello, este trabajo parte de las siguientes preguntas de investigación, ¿Existe alguna diferencia de género que sea dependiente de la edad en estudiantes de educación primaria en aspectos relacionados con las matemáticas? ¿Conoce el profesorado la autopercepción de sus estudiantes? Las principales contribuciones de este trabajo son que las diferencias significativas de género se observan en la percepción de autoeficacia de los estudiantes de primaria y ansiedad ante los exámenes en matemáticas. Las niñas se perciben a sí mismas significativamente peor que los niños en matemáticas e indican mayor ansiedad ante los exámenes de matemáticas. Las diferencias de género en la autoeficacia se vuelven más pronunciada a medida que los estudiantes crecen, mientras que la ansiedad ante los exámenes aumenta para todos los estudiantes. Pese a estos resultados, el presente estudio muestra que los profesores no perciben diferencias en la autoeficacia en matemáticas entre niños y niñas. Este estudio se basa en las encuestas realizadas a más de 2000 escolares (6-12 años) y 200 profesores en Aragón (España). El estudio consiste en una encuesta a los estudiantes sobre aspectos que pueden influir en la experiencia de los niños y niñas con las matemáticas, así como con la lengua española para disponer de una materia que permita establecer comparaciones y una encuesta al profesor que incluye cuestiones sobre su percepción de los estudiantes. El principal hallazgo del estudio es que, durante la escuela primaria, es más probable que las niñas experimenten una actitud negativa hacia matemáticas que los niños a medida que crecen, y que los maestros pueden no ser conscientes de la situación de las niñas
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