Importancia de la polinización del Kiwi (Actinia chinensis) en la calidad del fruto

Preprin

Detecció d'errors en l'aprenentatge dels triangles

Curs 2012-2013Aquest treball es basa en realitzar un estudi per tal d'identificar quins errors matemàtics cometen un grup d'alumnes de primer curs d'educació primària, en relació a la geometria. Concretament, aquest estudi és per identificar, mitjançant una prova, quines dificultats presenten els nens en relació als triangles. A partir dels errors que hagin sorgit, es dissenyarà la intervenció per tal d'intentar-los solucionar. Finalment, s'analitzarà si amb el treball realitzat els alumnes milloren els errors. En aquest treball s'ha utilitzat el mètode Concret-Representació-Abstracte de Bruner i les propostes que proposen certs autors (Bamberger, Schultz-Ferrell, ...) per ajudar a superar aquests errors. Realitzant aquest estudi s'ha pogut observar que els alumnes tenen la imatge d'un triangle prototípic. Això fa que cometin errors quan se'ls presenten altres triangles.This work is based on a study to identify mathematical errors committed by a group of students in their first year of primary education in relation to geometry. Specifically, this study is to identify, through a test, the difficulties children have in relation to triangles. From the errors that have arisen, the intervention is designed to try to solve them. Finally, we analyse whether the students, after the intervention, don't make similar errors. In this paper we have used the Bruner's method Concrete-Representational- Abstract and proposals that suggest some authors (Bamberger, Schultz-Ferrell, ...) to help overcome these errors. In this study it was observed that the students have the prototypical image of a triangle. Children make errors when showed other triangles

VPD-based models of dead fine fuel moisture provide best estimates in a global dataset

Dead fine fuel moisture content (FM) is one of the most important determinants of fire behavior. Fire scientists have attempted to effectively estimate FM for nearly a century, but we are still lacking broad scale evaluations of the different approaches for prediction. Here we tackle this problem by taking advantage or a recently compiled global fire behavior database (BONFIRE) gathering 1603 records of 1h (i.e., <6 mm diameter or thickness) dead fuel moisture content from measurements before experimental fires. We compared the results of models routinely used by different agencies worldwide, empirical models, semi-mechanistic models and also non-linear and machine learning approaches based on either temperature and relative humidity or vapor pressure deficit (VPD). A semi-mechanistic model based on VPD showed the best performance across all FM ranges and a historical model developed in Australia (MK5) was additionally recommended for low fuel moisture estimations. We also observed significant differences in FM dynamics between vegetation types with FM in grasslands more responsive to changes in atmospheric dryness than woody ecosystems. The addition of computational complexity through machine learning is not recommended since the gain in model fit is small relative to the increase in complexity. Future research efforts should concentrate on predictions at low FM (<10 %) as this is the range most significant for fire behavior and where the poorest model performance was observed. Model predictions are available from https://hcfm.shinyapps.io/shinyfmd/.This work was supported by the Portuguese Foundation for Science and Technology (projects UIDB/04033/2020 and PTDC/AAG-MAA/ 2656/2014), the Spanish MICINN (RTI2018-094691-B-C31, PID2020- 116556RA-I00) and EU H2020 (grant agreements 101003890-FirEUrisk, and 101037419-FireRES).info:eu-repo/semantics/publishedVersio

Estudio de la aptitud de diferentes variedades de cerezas para su transformación industria

Preprin

Esterification of levulinic acid with butanol over ion exchange resins

Alkyl levulinates are biobased chemicals with a great number of applications and great biofuel potential for blending to conventional diesel or gasoline. The present work focuses on the liquid-phase synthesis of butyl levulinate (BL) by esterification of levulinic acid (LA) with 1-butanol (BuOH) using a set of acidic ion-exchange resins. Experiments were performed at 80 °C and 2.5 MPa in a batch reactor by using an initial molar ratio AL/BuOH of 1/3 and a catalyst loading of 0.8%. It has been found that BL could be successfully obtained over ion-exchange resins with a selectivity higher than 99.5%. LA conversions ranged from 64% (Amberlyst 46, macroreticular, surface sulfonated) to 94% (Dowex 50Wx2, gel-type resin, conventionally sulfonated) at 8 h reaction time. By comparing their catalytic behavior, it was seen that resins morphology plays a very important role in the synthesis of BL making easier the access of reactants to acid sites. Accessibility of LA and BuOH to acid centers was high over highly swollen and low polymer density resins. Thus, gel-type resins with low divinylbenzene (DVB) content have been found as the most suitable to produce BL, e.g. Dowex 50Wx2, Dowex 50Wx4 and Purolite® CT224. Among them, Dowex 50Wx2 (2% DVB) is the most efficient catalyst tested

El aceite de oliva en nutrición clínica

The different beneficial effects of olive oil have a rational and scientific basis due to advances in the knowledge of lipid metabolism. The evidence that for a similar plasma cholesterol concentration, the rate of cardiovascular deaths is lower in the Mediterranean countries than in other ones, suggests that the beneficial effects of olive oil may not be only related to the known quantitative changes in plasma lipoproteins, but also to other, as yet unknown or little known, anti-atherogenic factors. The peculiarities of olive oil in terms of certain biochemical, biological and nutritional characteristics, open up a field of application in normal clinical practice. The benefits of olive oil in clinical nutrition correlate with its action on lipid metabolism and the cardiovascular system. Even a moderate increase in the ingestion of monounsaturated fats and a reduction in the ingestion of carbohydrates could be more advantageous in those patients with diabetes and hypertriglyceridemia and/or in those where loss of weight is not a priority. Different studies have also demonstrated the benefits of olive oil in different inflammatory and autoimmune diseases, such as rheumatoid arthritis. The chemical composition of extra virgin olive oil contributes to daily requirements of essential fatty acids and active antioxidant nutrients in vitamin E deficiency. This particular and well-balanced situation [oleic acid (18:1 n -9) and minor components in an ideal ratio] undoubtedly has a significant relevance in human clinical nutrition.Los avances en el conocimiento del metabolismo lipídico están permitiendo establecer las bases científicas de los efectos saludables del aceite de oliva. En los países del área Mediterránea, la mortalidad cardiovascular es menor que en otros, aunque la concentración de colesterol en sangre es similar. Es muy probable que la capacidad cardio-protectora del aceite de oliva se relacione con otros factores de riesgo, algunos de los cuales son poco o completamente desconocidos. Las propiedades bioquímicas, biológicas y nutricionales del aceite de oliva son peculiares y permiten su aplicación en la nutrición clínica. Los beneficios del aceite de oliva se correlacionan con su acción sobre el metabolismo lipídico y el sistema cardiovascular. Un aumento moderado en la ingesta de grasa monoinsaturada (aceite de oliva), a expensas de los carbohidratos, es la recomendación en pacientes con diabetes e hipertrigliceridemia. En nutrición clínica, el aceite de oliva también tiene efectos beneficiosos en enfermedades relacionadas con respuestas inflamatorias y autoinmunes, como la artritis reumatoide. La composición química del aceite de oliva virgen extra contribuye a las necesidades diarias de ácidos grasos esenciales y de antioxidantes, especialmente en situaciones patológicas de deficiencia en vitamina E. Sin duda, el aceite de oliva (virgen extra) tiene máxima relevancia, por su contenido de ácido oleico (18:1 n -9) y compuestos minoritarios, en la nutrición clínica

Real-World Safety and Effectiveness Evidence of a Microcrystalline Tyrosine-Associated Mite Allergoid in Children and Adolescents with Allergic Rhinitis

Rinitis al·lèrgica; Infants i adolescents; Tirosina microcristal·linaRinitis alérgica; Niños y adolescentes; Tirosina microcristalinaAllerghic rhinitis; Children and adolescents; Microcrystalline tyrosineEvidence regarding allergen immunotherapy (AIT) in pediatric population is scarce. We have assessed safety and effectiveness of subcutaneous AIT with a microcrystalline tyrosine (MCT)-associated mite allergoid, Acarovac Plus®, in children and adolescents with allergic rhinitis (AR), with and without asthma, in the real-world setting. This was a retrospective, multicenter study including children and adolescents aged 5 years to 17 years with AR, with and without asthma, and sensitized to mites, receiving AIT with Acarovac Plus® during ≥6 months. Primary and secondary objectives were safety and effectiveness, respectively. Effectiveness variables were assessed during 12 months before and after AIT and included unscheduled visits to the healthcare center and emergency room admissions, rhinitis and asthma symptoms according to ARIA and GEMA classifications, respectively, medication use, and patients’ and physicians’ disease perception graded on a visual analog scale (VAS). All 79 patients included had a mean (SD) age of 12.7 (3.3) years. Two patients experienced systemic adverse reactions (none severe). Unscheduled visits to the healthcare center and emergency room admissions decreased (mean (SD) 3.02 [2.48] and 0.63 [1.35] vs. 1.08 [1.38] and 0.09 [0.38], before and after treatment, p < 0.001 and p = 0.001, respectively). After AIT, rhinitis and asthma classification changed (p < 0.0001 for all classifications), showing improvements in symptoms and a significant decrease in rhinitis and use of medication for asthma and VAS scores grading patients’ and physicians’ disease perception (p < 0.001). In conclusion, these results show that AIT with an MCT-associated mite allergoid appears safe and effective in children and adolescents with AR treated in the real-world setting.This study was supported by Allergy Therapeutics Ibérica