Dos aproximaciones a la inquietud de investigación: 1. Una aproximación empírica y; 2. Una aproximación teórica

La presente reflexión forma parte de los avances de investigación doctoral titulada “Vivienda Social y Segregación Territorial en Lerma, Estado de México”, dentro del Programa de Posgrado en Diseño y Estudios Urbanos de la División de Ciencias y Artes para el Diseño en la UAM Azcapotzalco. Estas dos aproximaciones a la inquietud de investigación representan, por una parte, una aproximación empírica y por otra; una aproximación teórica. El objetivo es conocer la manera en que ambas se proponen, construyen y definen la estructura de la indagación. Al final conoceremos si ambas aproximaciones se complementan o se excluyen.This reflection is part of the advances in doctoral research “Vivienda Social y Segregación Territorial en Lerma, Estado de México”. Postgraduate Program in Design and Urban Studies, CYAD, UAM Azcapotzalco. These two approaches to the research concern represent, on the one hand, an empirical approach and on the other; a theoretical approach. The objective is to know the way in which both propose, construct, and define the structure of the inquiry. In the end we will know if both approaches complement or exclude each other.Coordinación de Posgrado de Ciencias y Artes para el Diseñ

Variable speed liquid chiller drop-in modeling for predicting energy performance of R1234yf as low-GWP refrigerant

This paper presents a model for a variable-speed liquid chiller integrating a compressor model based on Buckingham π-theorem to accurately predict the system performance when R134a is replaced with R1234yf, using a wide range of data obtained from an experimental setup. Relevant variables such as temperature, pressure, mass and volumetric flow rates, compressor power consumption and rotation speed were measured at several positions along the refrigeration and secondary circuits and were used to validate the developed model. Model results show that cooling capacity and power consumption predicted values are in good agreement with experimental data, within ±5%, being slightly higher for the deviation obtained for R134a than for R1234yf. Moreover, model results indicate that R1234yf has a reduction of coefficient of performance (COP) compared with R134a (between 2 and 11.3%), and that R1234yf COP reduction is diminished at intermediate volumetric flow rate and higher inlet temperature for the evaporator secondary fluid, respectively. On the other hand, an environmental analysis based on TEWI (total equivalent warming impact) method showed that direct emissions are almost negligible for R1234yf. However, there are no environmental benefits in terms of indirect greenhouse gas emissions using R1234yf without system modifications (as for instance the addition of internal heat exchanger or R1234yf new design components), which are required to reduce the liquid chiller climate change contribution using it as low GWP alternative in comparison with the typically used R134a refrigerant

Invited review: Artisanal Mexican cheeses

AbstractThe objective of this review is to present an overview of some of the most commonly consumed artisanal Mexican cheeses, as well as those cheeses that show potential for a protected designation of origin. A description is given for each of these cheeses, including information on their distinguishing characteristics that makes some of them potential candidates for achieving a protected designation of origin status. This distinction could help to expand their frontiers and allow them to become better known and appreciated in other parts of the world. Due to the scarcity of scientific studies concerning artisanal Mexican cheeses, which would ultimately aid in the standardization of manufacturing processes and in the establishment of regulations related to their production, more than 40 varieties of artisanal cheese are in danger of disappearing. To preserve these cheeses, it is necessary to address this challenge by working jointly with government, artisanal cheesemaking organizations, industry, academics, and commercial partners on the implementation of strategies to protect and preserve their artisanal means of production. With sufficient information, official Mexican regulations could be established that would encompass and regulate the manufacture of Mexican artisanal cheeses. Finally, as many Mexican artisanal cheeses are produced from raw milk, more scientific studies are required to show the role of the lactic acid bacteria and their antagonistic effect on pathogenic microorganisms during aging following cheese making

Comparative evaluation of R1234yf, R1234ze(E) and R450A as alternatives to R134a in a variable speed reciprocating compressor

A comparative energetic evaluation of R1234yf, R1234ze(E) and R450A as alternatives to R134a in a variable speed compressor is carried out. A compressor model based on dimensionless numbers was obtained using the Buckingham p -theorem, which was validated with experimental data; showing that the prediction error of the model is lower than ± 10% and ± 2 K for temperature. The experimental data were obtained by testing R134a, R1234yf, R1234ze(E) and R450A for a wide range of operating condi- tions. Results obtained with the validated model, show that the dimensionless approach provides a similar estimation of energy parameters compared with the experimental results, such as power con- sumption, refrigerant mass fl ow rate, cooling capacity, COP, discharge temperature and compressor ef- fi ciencies for each refrigerant tested using the dimensionless approach proposed. The comparative evaluation of the compressor predictions shows a reduction in the cooling capacity obtained with R1234yf, R450A and R1234ze(E), in comparison with R134a. Also, COP values for R1234yf, R450A, and R1234ze(E) are lower than those obtained from R134a. Finally, results shows that the dimensionless correlation compressor model can be used to predict the performance of other reciprocating compres- sors, at similar operating conditions for a wide range of compressor rotation speed, with a reasonable accuracy.The authors thankfully acknowledge to the "Consejo Nacional deCiencia y Tecnología (CONACYT)” for their support to this study, and to the “Ministerio de Educación, Cultura y Deporte” (Grant number FPU12/02841) for sponsoring this work through “Becas y Contratosde Formación de Profesorado Universitario del Programa Nacional de Formación de Recursos Humanos de Investigación del ejercicio 2012”

Low diversity and host specificity in the gut microbiome community of Eciton army ants (Hymenoptera: Formicidae: Dorylinae) in a Costa Rican rainforest

Neotropical army ants of the genus Eciton are top arthropod predators in tropical rainforests. Microbial symbionts, including Unclassified Firmicutes (UF) and Unclassified Entomoplasmatales (UE), are associated with this genus and likely play a significant role in the biology of these ants. While previous work focused on associations of army ants and gut microbes across large geographic scales, here we report a community survey of the gut microbes colonizing the six sympatric Eciton army ant species in a single Costa Rican location. Furthermore, we characterized the gut microbiota associated with different army ant castes in the swarm-raiding species Eciton burchellii. We employed a combination of 16S ribosomal RNA (rRNA) amplicon sequencing as well as fluorescence and electron microscopy to identify gut microbes and to verify their presence in ant guts. We also measured the diversity and interaction specificity of the ant-gut microbe interaction network. The two most dominant operational taxonomic unit (OTU) phylotypes in all species were related to UF and UE previously found in army ants, followed by OTUs assigned to the genus Weissella. Furthermore, the worker castes of E. burchellii shared similar gut microbiota, also dominated by UF and UE phylotypes. Overall, we found a low diversity of gut microbes and a low interaction specificity between army ants and microbes at the community level, mainly because most microbe strains were detected in various Eciton species. The fluorescence in-situ hybridization analyses documented the presence of the two dominant phylotypes within ant guts, and electron microscopy located bacterial biofilms in the hindgut near the microvilli. Their morphology suggests that these bacteria probably belong to the dominant phylotypes UF and UE. Taken together, our results confirm that the Eciton gut microbiome is consistently dominated by a few species of specialized bacteria that may improve nutrient uptake efficiency of host ants. Further research should employ multi-omics and culture-dependent strategies to fully understand the role of these potential symbionts in ant ecophysiology

Guía de práctica clínica para el diagnóstico y tratamiento de hemofilia en el Seguro Social de Salud del Perú (EsSalud)

Introduction. Hemophilia is a rare congenital bleeding disorder; which requires interdisciplinary, complex, and often expensive management. The objective of this clinical practice guideline (CPG) is to provide evidence-based clinical recommendations for the evaluation and management of patients with hemophilia in the Peruvian Social Security (EsSalud). Methods. A local elaboration group (GEG-Local) was established, conformed by specialists in hematology and methodologists. The GEG-Local formulated 8 clinical questions to be answered by this CPG. We searched for and selected hemophilia CPGs that answered the questions posed and obtained a score higher than 60% in domains 1 and 3 of the Appraisal of Guidelines for Research and Evaluation II (AGREE-II). During 2016, bibliographic searches were conducted in Pubmed, EMBASE and the Cochrane library, to update 7 clinical questions of the preselected CPG, and to answer a question de novo. In regular work meetings, the GEG-Local reviewed the evidence and formulated the recommendations and flowcharts using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology. Finally, the CPG was approved with Resolution No. 32-IETSI-ESSALUD-2016. Results. This CPG addressed 8 clinical questions. Based on these questions, 22 recommendations were formulated (three strong recommendations and 19 weak recommendations) and four flowcharts. Conclusion. This article is the summary of the EsSalud CPG, in which the available scientific evidence on the diagnosis and treatment of hemophilia was assessed.Introducción. La hemofilia es un trastorno hemorrágico congénito poco común que requiere un manejo interdisciplinario, complejo, y frecuentemente costoso. El objetivo de la presente guía de práctica clínica (GPC) es proveer recomendaciones clínicas basadas en evidencia para el diagnóstico y tratamiento de hemofilia en el seguro social del Perú (EsSalud). Métodos. Se conformó un grupo elaborador local (GEG-Local) conformado por especialistas en hematología y metodólogos. El GEG-Local formuló ocho preguntas clínicas a ser respondidas por la presente GPC. Se buscaron y seleccionaron GPC de hemofilia que respondieran a las preguntas planteadas y obtuvieran un puntaje mayor a 60% en los dominios uno y tres del instrumento Appraisal of Guidelines for Research and Evaluation II (AGREE-II). Durante el 2016 se realizaron búsquedas bibliográficas en Pubmed, EMBASE y biblioteca Cochrane, para actualizar siete preguntas clínicas de la GPC preseleccionada, y para responder una pregunta de novo. En reuniones de trabajo periódicas, el GEGLocal revisó la evidencia y formuló las recomendaciones y flujogramas usando la metodología Grading of Recommendations Assessment, Development, and Evaluation (GRADE). Finalmente, la GPC fue aprobada con Resolución N° 32-IETSI-ESSALUD-2016. Resultados. La presente GPC abordó ocho preguntas clínicas. En base a dichas preguntas se formularon 22 recomendaciones (tres recomendaciones fuertes y 19 recomendaciones condicionales) y cuatro flujogramas. Conclusión. Este artículo es el resumen de la GPC de EsSalud, en la cual se valoró la evidencia científica disponible sobre diagnóstico y tratamiento de hemofilia