1,251 research outputs found
X-ray microtomographic characterization of highly rough titanium cold gas sprayed coating for identification of effective surfaces for osseointegration
A highly rough titanium coating obtained by Cold Gas Spray (CGS) has been characterized by means of high-resolution 3D microtomography (micro-CT) with the aim to evaluate its open and close porosity for possible use in orthopaedic implants to promote osseointegration. Micro-CT allowed a qualitative and quantitative description of the main features, morphology of the pores and surface roughness of the coating. Several numerical values were obtained to describe size, form and distribution of the closed/inner and open/outer pores. Additionally, surface roughness and open porosity were image-analyzed to find the effective surface for osseointegration
An approach to age and growth of south Atlantic swordfish (Xiphias gladius) stock
A first growth function was estimated for the South Atlantic swordfish stock. A total of 406 anal fins were collected from 2006 to 2013. Fins were classified into three types and the most common, type A, was selected. Biometric relationships among several ray section measurements and lower jaw fork length were analysed. A detailed methodological description for swordfish age interpretation has been developed. Inconclusive results have been obtained when indirect validation test, as edge type and marginal increment ratio analysis, were applied. Mean size at age and growth parameters were estimated using the Standard Von Bertalanffy growth model (VBGM) (L∞= 358.7, k= 0.092, t0= -1.929), which showed the best fit in comparison with other VBGMs
Niveles de mercurio y percepción del riesgo en una población minera aurífera del Guainía (Orinoquia colombiana)
Gold mining in the Colombian Orinoquia region had a fast growth in the last 15 years. Mercury is used during the gold amalgam process, and its presence is an important problem of public health because it produces a polluted ecosystem and increases the risk of mercury-related adverse health effects among the exposed human population. The main objective of this study was to determine the mercury levels in blood and hair, and the risk perception of the mercury exposure in a population from Guainía. Fifty-nine blood and sixty-one hair samples were collected to measure the mercury concentration. The findings show a very deteriorated occupational environment that results in contamination of the Orinoquia ecosystem. The subjects perceived the mercury exposure like noxious to their health, although their knowledge about mercury-related health effects is inadequate. The mercury levels in blood are between 6.9 and 168.0 ug/l (mean=59.16) among the mining workers, and between 17.7 y 100.8 ug/l (meanz53.50) among subjects indirectly exposed. The total mercury levels in hair are between 3.0 and 89.2 ud/g (mean=26.93) among the mining workers, and from 2.8 to 48.70 ug/g (meam22.86) among subjects indirectly exposed. No significant differences were found between the two exposure groups studied. We suggest preventive and control measures to minirnize the exposure to mercuty related with gold mining in the region under study.La minería aurífera en la región de la Orinoquia colombiana ha tenido un importante crecimiento en los últimos 15 años. Esta actividad se ha convertido en un importante problema de salud pública debido a varios factores como el uso de mercurio durante el proceso de amalgamación del oro, la contaminación del ecosistema y la exposición de la población de la región. El objetivo del presente trabajo fue determinar los niveles de mercurio en cabello y sangre en una población minera del departamento del Guainía y la percepción que tiene dicha población del riesgo de usar este elemento. Para tal fin, se encuestaron 78 residentes de la región, de los cuales se obtuvieron 59 muestras de sangre y 61 de cabello. Los resultados indican un precario ambiente laboral y una falta de conocimiento del riesgo ecológico, lo cual permite la contaminación del ecosistema de la Orinoquia. Los individuos perciben la exposición al mercurio como nociva para la salud, aunque sus conocimientos al respecto son inadecuados. Los valores de mercurio en sangre entre los mineros oscilaron entre 6,9 y 168,0 ug/l (promedio=59,16) y entre los individuos indirectamente expuestos fluctuó entre 17,7 y 100,8 ug/l (promedio=53,5). Las concentraciones de mercurio total en cabello oscilaron entre 3,0 y 89,2 ug/g (promedio=26,93) en el grupo de mineros y entre 2,8 y 48,7 ug/g (promedio=22,86) entre los expuestos indirectamente. No se encontraron diferencias significativas en los niveles de mercurio entre los dos grupos estudiados. Se sugieren medidas preventivas y de control de la situación generada por el uso de mercurio en las labores de mineria aurífera de la región
Students' perception on learning methods in engineering disciplines
This article is (c) Emerald Group Publishing and permission has been granted for this version to appear here (please insert the web address here). Emerald does not grant permission for this article to be further copied/distributed or hosted elsewhere without the express permission from Emerald Group Publishing Limited.[EN] Purpose - This study explores the preferences for learning methods among the students of seven engineering disciplines in a Spanish technical university. The purpose of this paper is to investigate the students' views and from them contribute to the knowledge of the effectiveness of learning methodologies.
Design/methodology/approach - An online anonymous questionnaire survey was adopted to collect students' perceptions. Seven learning methods were compared in seven engineering degrees. The authors sampled 1660 students, and 426 completed responses were analysed. In addition to a descriptive analysis of the results, a multiple correspondence analysis (MCA) was performed using R data processing software.
Findings - It was found that project-based learning and problem-based learning were perceived as the more effective ones. MCA identified response patterns between the preference and the efficiency of learning methods showing that students can be classified into two groups according to their preferred level of activeness in learning.
Research limitations/implications - The study focusses on a single technical university and not all engineering degrees could be sampled. However, five different engineering fields were studied and no significant differences among them were found.
Practical implications - The results add up to the known literature showing that students have different learning needs and consequently they perceive some methods as more effective. Instructors can use this information to strengthen their learning activities. Results also suggest that students can be classified into two groups in relation to their level of activeness in learning. This can also help to enhance general student motivation if two paths with different levels of activeness are planned.
Originality/value - No previous studies have compared several learning methods in different engineering fields. Thus, this study contributes to fill this gap and contributes to the body of evidence around learning methodologies from the perspective of students.Vidal Rodriguez, B.; Fenollosa Ribera, ML.; Ribal, J.; Sanchis Kilders, P.; García-Rupérez, J.; Bes-Piá, M.; Blasco-Tamarit, E.... (2022). Students' perception on learning methods in engineering disciplines. Journal of Applied Research in Higher Education. 14(3):946-957. https://doi.org/10.1108/JARHE-01-2021-0041S94695714
Variation for Composition and Quality in a Collection of the Resilient Mediterranean 'de penjar' Long Shelf-Life Tomato Under High and Low N Fertilization Levels
[EN] The 'de penjar' tomato (Solanum lycopersicum L.) is a group of local varieties from the Spanish Mediterranean region carrying the alc mutation, which provides long shelf-life. Their evolution under low-input management practices has led to the selection of resilient genotypes to adverse conditions. Here we present the first evaluation on nutritional fruit composition of a collection of 44 varieties of 'de penjar' tomato under two N fertilization levels, provided by doses of manure equivalent to 162 kg N ha(-1) in the high N treatment and 49 kg N ha(-1) in the low N treatment. Twenty-seven fruit composition and quality traits, as well as plant yield and SPAD value, were evaluated. A large variation was observed, with lycopene being the composition trait with the highest relative range of variation (over 4-fold) under both N treatments, and significant differences among varieties were detected for all traits. While yield and most quality traits were not affected by the reduction in N fertilization, fruits from the low N treatment had, on average, higher values for hue (5.9%) and lower for fructose (-11.5%), glucose (-15.8%), and total sweetness index (-12.9%). In addition, lycopene and beta-carotene presented a strongly significant genotype x N input interaction. Local varieties had higher values than commercial varieties for traits related to the ratio of sweetness to acidity and for vitamin C, which reinforces the appreciation for their organoleptic and nutritional quality. Highest-yielding varieties under both conditions displayed wide variation in the composition and quality profiles, which may allow the selection of specific ideotypes with high quality under low N conditions. These results revealed the potential of 'de penjar' varieties as a genetic resource in breeding for low N inputs and improving the organoleptic and nutritional tomato fruit quality.This work has been funded by the European Union's Horizon 2020 Research and Innovation Programme under grant agreement no. 774244 (Breeding for resilient, efficient and sustainable organic vegetable production; BRESOV), by the Spanish Agencia Estatal de Investigacion under grant agreement no. PCI2019-103375 (project SOLNUE in the framework of the H2020 call SusCrop-ERA-Net; ID#47), and by Generalitat Valenciana (Conselleria d'Innovacio, Universitats, Ciencia I Societat Digital) under grant agreement no. AICO/2020/042. ER-M is grateful to the Spanish Ministerio de Economia, Industria y Competitividad for a pre-doctoral grant (BES-2016-077482).Rosa-Martínez, E.; Adalid-Martinez, AM.; Alvarado, LE.; Burguet-Belda, R.; García-Martínez, MD.; Pereira-Días, L.; Casanova-Calancha, C.... (2021). Variation for Composition and Quality in a Collection of the Resilient Mediterranean 'de penjar' Long Shelf-Life Tomato Under High and Low N Fertilization Levels. Frontiers in Plant Science. 12:1-19. https://doi.org/10.3389/fpls.2021.6339571191
Development of lessons on chemical and biological reactors in Moodle platform
En este proyecto docente se han desarrollado una serie de actividades académicamente dirigidas dedicadas a los reactores químicos y biológicos, en concreto, se ha empleado una herramienta denominada lección que se encuentra disponible a través de la plataforma virtual Moodle, dichas lecciones se basan en una serie de ventanas secuenciales que permiten profundizar en todos los conceptos fundamentales de los reactores químicos y/o biológicos y, a través de diversas cuestiones complementarias sobre el tema, incluidas durante el desarrollo de dicha lección, permite al alumno realizar un aprendizaje más activo que favorece la consolidación de los conceptos de forma gradual. Previo al estudio de los reactores químicos y/o biológicos es necesario tener en cuenta diversos aspectos químicos, físicos, matemáticos, biológicos e ingenieriles que han de considerarse para desarrollar los aspectos fundamentales básicos para poder alcanzar dicho objetivo y se pretende facilitar esta labor al alumnado con el empleo de las lecciones elaboradas. Previamente a la elaboración de las lecciones se ha realizado una importante labor de preparación y síntesis de toda la información, posteriormente se han desarrollado diferentes lecciones para los conceptos tratados en cada uno de los temas implicados en la elaboración de este proyecto docente y tras una profunda revisión se han puesto a disposición de los alumnos.In this teaching project have developed a series of academic activities devoted to the chemical and biological reactors, in particular, it has been using a tool called lesson which is available through the Moodle virtual platform, these lessons are based on a series of sequential windows allowing to delve into all the fundamental concepts of chemical and/or biological reactors and through various complementary on the theme, including issues during the development of this lesson, students perform a more active learning that promotes the consolidation of concepts gradually. Prior to the study of chemical reactors and/or biological is necessary to take account of various chemical, physical, mathematical, biological and engineering aspects that are to be considered to develop the basic fundamentals to achieve the aim and is intended to facilitate this work to the students with the use of elaborate lessons. Important preparation work has been prior to the preparation of the lessons and synthesis of information, have subsequently developed different lessons for the concepts dealt with in each of the issues involved in the development of this educational project and after a thorough review have been available to the students
Gibberellin A1 Metabolism Contributes to the Control of Photoperiod-Mediated Tuberization in Potato
Some potato species require a short-day (SD) photoperiod for tuberization, a process that is negatively affected by gibberellins (GAs). Here we report the isolation of StGA3ox2, a gene encoding a GA 3-oxidase, whose expression is increased in the aerial parts and is repressed in the stolons after transfer of photoperiod-dependent potato plants to SD conditions. Over-expression of StGA3ox2 under control of constitutive or leaf-specific promoters results in taller plants which, in contrast to StGA20ox1 over-expressers previously reported, tuberize earlier under SD conditions than the controls. By contrast, StGA3ox2 tuber-specific over-expression results in non-elongated plants with slightly delayed tuber induction. Together, our experiments support that StGA3ox2 expression and gibberellin metabolism significantly contribute to the tuberization time in strictly photoperiod-dependent potato plants
IFNγ Response to Mycobacterium tuberculosis, Risk of Infection and Disease in Household Contacts of Tuberculosis Patients in Colombia
OBJECTIVES: Household contacts (HHCs) of pulmonary tuberculosis patients are at high risk of Mycobacterium tuberculosis infection and early disease development. Identification of individuals at risk of tuberculosis disease is a desirable goal for tuberculosis control. Interferon-gamma release assays (IGRAs) using specific M. tuberculosis antigens provide an alternative to tuberculin skin testing (TST) for infection detection. Additionally, the levels of IFNgamma produced in response to these antigens may have prognostic value. We estimated the prevalence of M. tuberculosis infection by IGRA and TST in HHCs and their source population (SP), and assessed whether IFNgamma levels in HHCs correlate with tuberculosis development. METHODS: A cohort of 2060 HHCs was followed for 2-3 years after exposure to a tuberculosis case. Besides TST, IFNgamma responses to mycobacterial antigens: CFP, CFP-10, HspX and Ag85A were assessed in 7-days whole blood cultures and compared to 766 individuals from the SP in Medellín, Colombia. Isoniazid prophylaxis was not offered to child contacts because Colombian tuberculosis regulations consider it only in children under 5 years, TST positive without BCG vaccination. RESULTS: Using TST 65.9% of HHCs and 42.7% subjects from the SP were positive (OR 2.60, p<0.0001). IFNgamma response to CFP-10, a biomarker of M. tuberculosis infection, tested positive in 66.3% HHCs and 24.3% from the SP (OR = 6.07, p<0.0001). Tuberculosis incidence rate was 7.0/1000 person years. Children <5 years accounted for 21.6% of incident cases. No significant difference was found between positive and negative IFNgamma responders to CFP-10 (HR 1.82 95% CI 0.79-4.20 p = 0.16). However, a significant trend for tuberculosis development amongst high HHC IFNgamma producers was observed (trend Log rank p = 0.007). DISCUSSION: CFP-10-induced IFNgamma production is useful to establish tuberculosis infection prevalence amongst HHC and identify those at highest risk of disease. The high tuberculosis incidence amongst children supports administration of chemoprophylaxis to child contacts regardless of BCG vaccination
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