139 research outputs found
Preparation of some alkynes and alkenynes
The following thesis concerns the preparation of several alkynes and their conversion to alkenynes. Alkynes are of interest because of their potential biological activity (1), general reactivity to boranes (2), complexing ability with some transition metals (3), as well as other general reactions of π bonds (4). It was the intention of this investigation to prepare several alkynes with varying degrees of steric hindrance and evaluate the effect of this property. Double bonds were incorporated in several of these compounds to aid in the assessment
Interpolation réelle avec une fonction paramètre
We first discuss the existing relations between the Boyd functions and the admissible sequences
with a particular interest to the Boyd indices. These notions are intended to be tools
in order to generalize some functional spaces. Here, we generalize certain classic results of interpolation theory such as the Aronzajn-Gagliardo theorem
Generalized Interpolation: a Functorial Point of View
Many spaces, such as the Besov spaces, naturally arise through the (real)
interpolation theory. A classical generalization of these interpolation methods has been introduced in
the eighties. The idea is to replace the linear formula (1 -alpha)t + alpha u by a more
general function alpha -> f(alpha). As the interpolation theory can be expressed using
the language of categories, it is natural to do the same with the generalized
interpolation spaces. This is the purpose of this talks.
We first discuss the existing relations between the Boyd functions and the
admissible sequences, with a particular interest to the Boyd indices. These
notions are intended to be tools in order to generalize some functional spaces.
We then define interpolation functors depending on Boyd functions from the
category of compatible normed vector spaces to the category of normed vector
spaces. Next, we generalize some classic results of interpolation theory and
apply them to some classical functional spaces
Prediction of the efficiency for decision making in the agricultural sector through artificial intelligence
Agriculture plays an important role in Latin American countries where the demand for provisions to reduce hunger and poverty represents a significant priority in order to improve the development and quality of life in the region. In this research, linear data analysis techniques and soil classification are reviewed through neural networks for decision making in agriculture. The results permit to conclude that precision agriculture, observation and control technologies are gaining ground, making it possible to determine the production demand in these countrie
Youth study Growing up in Central Eastern Europe 2022: An international comparison of the living conditions of young people in Czech Republic, Hungary, Poland and Slovakia
In the Visegrad Four countries - Poland, Slovakia, the Czech Republic and Hungary - economic and socioeconomic issues are of prime importance. Especially for young women, youth unemployment rates continue to pose a challenge in the region. This study is based on a representative survey of 6,000 young people aged 15 to 29 in the Visegrad 4 countries, conducted in 2021 with a quantitative and qualitative approach. It aims to shed light on the everyday realities, values, and political opinions of young people in Central Europe
Model for predicting academic performance in virtual courses through supervised learning
Since virtual courses are asynchronous and non-presential environments, the following of student tasks can be a hard work. Virtual Education and Learning Environments (VELE) often provide tools for this purpose (Zaharia et al. in Commun ACM 59(11):56-65, 2016, [1]). In Moodle, some plugins take information about students’ activities, providing statistics to the teacher. This information may not be accurate with respect to leadership ability or risk of abandonment. The use of artificial neural networks (ANNs) can help predict student behavior and draw conclusions at early stages of the learning process in a VELE. This paper proposes a plugin for Moodle that analyzes social metrics through graph theory. This article outlines the advantages of integrating an ANN into this development that complements the use of the graph to provide rich conclusions about student performance in a Moodle virtual course
Biotipos y susceptibilidad antimicrobiana de S. mutans en niños con y sin caries dental
Objetivos: investigar los biotipos de S. mutans aislados de niños con y sin caries dentaly determinar su susceptibilidad antimicrobiana. Métodos: este estudio observacionaldescriptivo incluyó 206 niños entre los 3 y 5 años de dos preescolares en Bogotá, D.C., Colombia. Después de su aislamiento en agar Mitis Salivarius Bacitracina, lascepas S. mutans se identificaron por pruebas bioquímicas y se biotipificaron por elsistema api-ZYM. En todos los aislamientos se determinó por el método de diluciónenvagar la concentración inhibitoria mínima (CIM) de Penicilina, Amoxicilina, Cefazolina, Eritromicina, Clindamicina, Imipenem, Vancomicina y Teicoplanina.Resultados: Se encontró S. mutans en 30 de los 79 niños sin caries dental (38%) y en56 de los 127 niños con caries (44,1%). Los niños con caries presentaron un recuentosuperior de S. mutans en comparación con los niños sin caries (p 0,05). En totalse identificaron 121 cepas de S. mutans en los 86 niños: 43 cepas en los 30 niños sincaries dental y 78 en los 56 niños con caries dental. Las 121 cepas fueron agrupadasen 38 biotipos: 24 en el grupo de caries y 14 en el grupo sin caries. En el grupo decaries los biotipos más frecuentes fueron el XV, XI, XII y XVII, respectivamente,con 26, 12, 11 y 4 cepas y en el grupo sin caries los biotipos más frecuentes fueronel XXVI, XX y XXXVI, respectivamente, con 14, 8 y 7 cepas. Todos los biotiposObjectives: The main objective was to investigate the biotypes of S. mutans isolated from children with and without dental caries and determine its antimicrobial susceptibility. Methods: this descriptive observational study included 206 children aged 3 to 5 years of two preschool institutions in Bogota-Colombia. After isolation on agar Mitis Salivarius Bacitracin, S. mutans strains were identified by biochemical tests and biotyped by the api-ZYM system. The minimal inhibitory concentrations (MICs) of the S. mutans isolates were evaluated against penicillin, amoxicillin, cefazolin, erythromycin, clindamycin, imipenem, vancomycin and teicoplanin by an agar dilution method. Results: S. mutans was found in 30 of the 79 children without dental caries (38%) and in 56 of the 127 children with caries (44.1%). Children with cavities had a higher count of S. mutans compared to children without caries (p 0.05). A total of 121 strains of S. mutans were identified in 86 children: 43 strains in 30 children with dental caries and 78 in the 56 children with dental caries. The 121 strains were grouped into 38 biotypes: 24 in the group caries and 14 in the group without caries. In the group caries the most common biotypes were the XV, XI, XII and XVII, respectively, with 26, 12, 11 and 4 strains and the group caries the most common biotypes were the XXVI, XX and XXXVI, respectively, with 14, 8 and 7 strains. All biotypes were highly sensitive to all antimicrobials tested; 50 and 90% of S. mutans strains were inhibited by using concentrations lower than 0.12 and 1 µg/ml, respectively, for all antibiotics studied. The lowest MICs average values were obtained for penicillin, erythromycin and imipenem. Conclusions: In the study population a wide variety of biotypes was found, isolates were highly sensitive to antimicrobials evaluated and in each clinical group were identified unique patters that could indicate a specific colonization
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