Modelo analítico para sistema de descarga de calor en techos

En el presente trabajo, se propone un modelo analítico que describe el comportamiento térmico de un sistema de descarga de calor en techo. Para validarlo, se empleó un prototipo experimental al cual se le realizó una prueba con exposición al sol y se comparó los resultados medidos con los calculados por un modelo analítico propuesto por lo autores. Se encontró variaciones de error entre los datos tomados en la prueba experimental y en el modelo analítico de 6.5 ºC como máximo para la placa de aluminio (o almacenadora de calor) y de 4.6 ºC como máximo para la temperatura en la superficie del vidrio. Se considera que el modelo analítico propuesto puede ser empleado para conocer el comportamiento de un sistema de descarga de calor en techos definiendo las dimensiones del sistema para las condiciones ambientales del lugar donde se va a utilizar.Fil: Hernández G., Víctor. Universidad Nacional Autónoma de México; MéxicoFil: Fernández Z., José. Universidad Nacional Autónoma de México; MéxicoFil: Morillón Galvez, David. Universidad Nacional Autónoma de México; MéxicoFil: Mesa, Nestor Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ciencias Humanas, Sociales y Ambientales; Argentin

Analyzing Modern Biomolecules: The Revolution of Nucleic-Acid Sequencing-Review

Recent developments have revolutionized the study of biomolecules. Among them are molecular markers, amplification and sequencing of nucleic acids. The latter is classified into three generations. The first allows to sequence small DNA fragments. The second one increases throughput, reducing turnaround and pricing, and is therefore more convenient to sequence full genomes and transcriptomes. The third generation is currently pushing technology to its limits, being able to sequence single molecules, without previous amplification, which was previously impossible. Besides, this represents a new revolution, allowing researchers to directly sequence RNA without previous retrotranscription. These technologies are having a significant impact on different areas, such as medicine, agronomy, ecology and biotechnology. Additionally, the study of biomolecules is revealing interesting evolutionary information. That includes deciphering what makes us human, including phenomena like non-coding RNA expansion. All this is redefining the concept of gene and transcript. Basic analyses and applications are now facilitated with new genome editing tools, such as CRISPR. All these developments, in general, and nucleic-acid sequencing, in particular, are opening a new exciting era of biomolecule analyses and applications, including personalized medicine, and diagnosis and prevention of diseases for humans and other animals

Capital humano y descentralizacion de la educacion. El caso para Tlajomulco de Zuñiga, Jalisco

Este trabalho tem por objetivo analisar e determinar o capital humano no processo de descentralização da educação no município de Tlajomulco de Zuniga, Jalisco. Este objectivo é confirmar o relacionamento positivo há uma escolaridade de renda direta destinado a medir como as variáveis de impacto e gerar variações de renda diretamente o andamento do projeto. Assim, na hipótese de capital humano inicial sobre escolaridade em relação ao rendimento de uma nova variável que influencia integra de forma positiva. A pesquisa é principalmente evidência empírica através da análise matemática, estatística e económica. Os resultados confirmam a teoria do capital humano através do impacto de um maior nível de educação sobre a renda dos indivíduos em seu trabalho

Measuring online teaching service quality in higher education in the COVID-19 environment

The use of the Internet to develop new technologies has generated a considerable change in teaching and student learning in higher education. The pandemic caused by COVID-19 has forced universities to switch from face-to-face to online instruction. Furthermore, this transfer process was planned and executed quickly, with urgent redesigns of courses originally conceived for live teaching. The aim of this work is to measure the service quality of online teaching delivered during the COVID- 19 period. The methodology was based on an importance-performance analysis using a structural equations model. The data were obtained from a sample of 467 students attending a university in southern Spain. The results reveal five priority attributes of online teaching that need to be improved in order to enhance the service quality of the virtual instruction provided to students. Universities need to redefine their online format by integrating methodological and technological decisions and involving collaboration between teachers, students and administration staff and services. The results do not apply to educational institutions that exclusively teach courses online, but to those institutions that had to rapidly adapt, and shift course material originally designed for face-to-face training

Highly efficient potentiometric glucose biosensor based on functionalized InN quantum dots

We present a fast, highly sensitive, and efficient potentiometric glucose biosensor based on functionalized InN quantum-dots (QDs). The InN QDs are grown by molecular beam epitaxy. The InN QDs are bio-chemically functionalized through physical adsorption of glucose oxidase (GOD). GOD enzyme-coated InN QDs based biosensor exhibits excellent linear glucose concentration dependent electrochemical response against an Ag/AgCl reference electrode over a wide logarithmic glucose concentration range (1 × 10−5 M to 1 × 10−2 M) with a high sensitivity of 80 mV/decade. It exhibits a fast response time of less than 2 s with good stability and reusability and shows negligible response to common interferents such as ascorbic acid and uric acid. The fabricated biosensor has full potential to be an attractive candidate for blood sugar concentration detection in clinical diagnoses

Amplified Spontaneous Emission in Pentathienoacene Dioxides by Direct Optical Pump and by Energy Transfer: Correlation with Photophysical Parameters

Amplified spontaneous emission (ASE) is observed, under optical pump, in polystyrene films doped with two pentathienoacene derivatives functionalised with thienyl-S,S-dioxide groups (compounds 2 and 3). The effect of the dioxide groups on the ASE properties is analysed by comparing the performance with that of its corresponding non-oxidized analogue (1). Films containing either 2 or 3 show ASE at 511 and 574 nm, respectively, when excited directly (at 435 nm) on their absorption bands, showing thresholds and linewidths larger than those obtained from films doped with 1, pumped at 355 nm. ASE is also observed under excitation at 355 nm, in samples containing 1 (host) and either 2 or 3 (guests), due to energy transfer from host to guest. For the blends with 3, the ASE threshold is lower than that obtained when the films are excited directly. Results are interpreted in terms of the photophysical parameters such as absorption capacity, fluorescence efficiency, singlet-to-triplet intersystem crossing leading to triplet-triplet re-absorptions, bimolecular energy-transfer efficiency, efficiency of internal conversion process, etc. State-of-the-art quantum chemical calculations are used in the interpretation of the experimental results.Authors from the University of Alicante acknowledge support from the Spanish Government (MINECO) and the European Community (FEDER) through grants MAT2008–06648-C02–01 and MAT2011–28167-C02–01. The work at the University of Málaga is supported by the MEC projects CTQ2012–33733 and by the PO9–4708 project by the Junta de Andalucía. Raquel Rondão acknowledges FCT for a PhD grant (SFRH/BD/38882/2007). D.A.S.F. gratefully acknowledges the financial support from the Brazilian Research Councils: CAPES, CNPq (grant 303084/2010–3) and FAP-DF (Fundação de Apoio à Pesquisa do Distrito Federal)

Model mjerenja učinkovitosti učenja i zadovoljstva studenata tijekom pandemije bolesti COVID-19

The aim of this research was to assess the learning efficacy and level of satisfaction of university students as they adapted to the online teaching model amid the restrictions imposed as a result of COVID-19. The sample consisted of 467 students attending a public University of Spain. The study applied a structural equations methodology with a triangulated approach. The results show that the most influential factor in student online learning satisfaction is teacher-student interaction. On the other hand, student learning efficacy mainly depends on their attitude towards the use of technology; this makes it essential to understand which elements of the online learning system facilitate and incentivize the creation of a good learning environment. Moreover, the design quality of the system and the tools that make it function, and how they link to content and competences, all directly influence perceived ease-of-use and student satisfaction with online teaching.Cilj ovoga istraživanja bio je procijeniti učinkovitost učenja i razinu zadovoljstva studenata tijekom privikavanja na online nastavu uslijed ograničenja nametnutih zbog pandemije bolesti COVID-19. Uzorak ispitanika sastojao se od 467 studenata državnoga sveučilišta u Španjolskoj. U istraživanju je primijenjena metodologija strukturnih jednadžbi i pristup triangulacije. Rezultati pokazuju da je najutjecajniji faktor zadovoljstva učenjem u online okružju interakcija između studenta i nastavnika. S druge strane, učinkovitost učenja najviše ovisi o njihovim stavovima prema korištenju tehnologije. Zbog toga je nužno razumjeti koji elementi učenja u online okružju pomažu i potiču stvaranje dobroga okružja za učenje. Štoviše, kvaliteta dizajna sustava, alati koji im omogućuju rad te kako se oni povezuju sa sadržajem i kompetencijama zajedno izravno utječu na percepciju lakoće korištenja i na zadovoljstvo studenata online nastavom

Transmission of light in deep sea water at the site of the ANTARES neutrino telescope

The ANTARES neutrino telescope is a large photomultiplier array designed to detect neutrino-induced upward-going muons by their Cherenkov radiation. Understanding the absorption and scattering of light in the deep Mediterranean is fundamental to optimising the design and performance of the detector. This paper presents measurements of blue and UV light transmission at the ANTARES site taken between 1997 and 2000. The derived values for the scattering length and the angular distribution of particulate scattering were found to be highly correlated, and results are therefore presented in terms of an absorption length;,ab, and an effective scattering length lambda(sct)(eff). The values for blue (UV) light are found to be lambda(abs) similar or equal to 60(26) m, lambda(sct)(eff similar or equal to) 265(122) m, with significant (similar to15%) time variability. Finally, the results of ANTARES simulations showing the effect of these water properties on the anticipated performance of the detector are presented

STRATEGIC INTERNATIONALIZATION OF MEXICAN EMERGING MULTINATIONALS

The opening of the Mexican economy and globalization bring new opportunities for Mexican companies to expand their markets and get their products around the world. The internationalization process requires a sound strategy for the consolidation in foreign markets. The aim of this study is to analyze the different internationalization strategies followed by three Mexican companies with a global presence: Grupo Modelo, Grupo Bimbo and Cemex. We conclude that the differences in their strategies arise from the characteristics of each of these companies