Universidad Nacional Autonoma De Mexico Research Articles

Surface-deposition and distribution of the radon-decay products indoors

The exposure to radon-decay products is of great concern both in dwellings and workplaces. The model to estimate the lung dose refers to the deposition mechanisms and particle sizes. Unfortunately, most of the dose data available are based on the measurement of radon concentration and the concentration of radon decay products. These combined measurements are widely used in spite of the fact that accurate dose assessments require information on the particle deposition mechanisms and the spatial distribution of radon decay products indoors.Most of the airborne particles and/or radon decay products are deposited onto indoor surfaces, which deposition makes the radon decay products unavailable for inhalation. These deposition processes, if properly known, could be successfully exploited to reduce the exposure to radon decay products. In spite of the importance of the surface deposition of the radon decay products, both for the correct evaluation of the dose and for reducing the exposure; little or no efforts have been made to investigate these deposition processes. Recently, two parallel investigations have been carried out in Rome and at Universidad Nacional Autónoma de México (UNAM) in Mexico City respectively, which address the issue of the surface-deposited radon decay products. Even though these investigations have been carried independently, they complement one another. It is with these considerations in mind that it was decided to report both investigations in the same paper.

Developmental Alterations of Teeth in Young Patients

Research motivation: The objective of this study was to know the frequency of dental developmental alterations in Mexican children and adolescents attending the Stomatological Clinics of the Faculty of Dentistry of the Universidad Nacional Autonoma de Mexico. Research design/methodology: The files of the patients attended in our institution were reviewed and 128 were from patients among 2 and 18 years old with dental developmental alterations were selected. Data on diagnosis, age, gender and involved tooth were analyzed by Students T test and p<0.05 was considered significant. Main findings: The most frequent dental developmental alterations were: supernumeraries, missing teeth and fused teeth. Other entities were also found. Prevalence of dental alterations in the sample was 29.8% and 217 dental alterations were diagnosed. Of 217 teeth, 83.4% were permanent and 16.6% were deciduous teeth. Implications: Data obtained from this study will address the consciousness of the authorities and personnel of the institutions involved in providing health services on the importance to conduct imagenologic studies in children and adolescent population for early recognition of the intrabony pathological conditions.

Development of a Capillary Rheometer for the Characterization of Heavy and Extra-Heavy Oils

Viscosity and flow behavior of crude oils are key properties for the characterization, management, and development of petroleum reservoirs. To measure the rheological properties of heavy crude oils with a high accuracy, a capillary rheometer was designed and built at the Ruhr University in Bochum (RUB), Germany. The capillary rheometer was calibrated with three Newtonian reference blends of 1000, 10 000, and 50 000 mPa s. For these standards, the viscosity tables have been extended up to 1000 bar in the temperature range of 20–120 °C. The extended viscosity data were determined with a falling body viscometer at the Universidad Nacional Autónoma de México (UNAM), obtaining average deviations better than 2.0% at high pressure. The capillary rheometer is then calibrated with the same reference fluids at 40, 60, 80, and 100 °C at pressures from 1 to 260 bar. The deviation from the reference value was found to be lower than 3% at high pressure. The flow behavior of a heavy oil sample is determined at 80, 100, and 120 °C at atmospheric pressure. Furthermore, the viscosity is measured from atmospheric pressure to 180 bar. The investigated heavy oil shows a Newtonian behavior at high temperatures. This is consistent with rheological measurement carried out at UNAM. The viscosity increases with increasing pressure at all temperatures. For example, at 40 °C, the viscosity increases by about 35% by increasing the pressure from 1 to 100 bar.

Surface-deposition and Distribution of the Radon (222Rn and 220Rn) Decay Products Indoors

The exposure to radon (222Rn and 220Rn) decay products is of great concern both in dwellings and workplaces. The model to estimate the lung dose refers to the deposition mechanisms and particle sizes. Unfortunately, most of the dose data available are based on the measurement of radon concentration and the concentration of radon decay products. These combined measurements are widely used in spite of the fact that accurate dose assessments require information on the particle deposition mechanisms and the spatial distribution of radon decay products indoors. Most of the airborne particles and/or radon decay products are deposited onto indoor surfaces, which deposition makes the radon decay products unavailable for inhalation. These deposition processes, if properly known, could be successfully exploited to reduce the exposure to radon decay products. In spite of the importance of the surface deposition of the radon decay products, both for the correct evaluation of the dose and for reducing the exposure, little or no efforts have been made to investigate these deposition processes. Recently, two parallel investigations have been carried out in Rome and at Universidad Nacional Autónoma de México (UNAM) in Mexico City respectively, which address the issue of the surface-deposited radon decay products. Even though these investigations have been carried independently, they complement one another. It is with these considerations in mind that it was decided to report both investigations in the same paper.

Discursive Interactions between University Students during a Laboratory Practice Using SDIS-GSEQ

This paper shows the discourse analysis among students during a laboratory practice using the Software SDIS-GSEQ; the cooperation and teamwork among students are analyzed through their discursive participation in order to streamline their learning and performance in a laboratory practice. The study group consisted of students from the second semester of Biology of Facultad de Estudios Superiores Iztacala, in Universidad Nacional Autonoma de Mexico. The process involved the creation of an instrument in which a set of categories were articulated and a verbal subsystem with subcategories was defined based on the discourse; the software SDIS-GSEQ was used and it established the categorical sequences that were present in the interaction of students during the practice. The results show inhibitory and excitatory categories, as well as flows and cycles of discursive interactions, the latter of which is defined as static and dynamic; the results also include complex discursive cycles, from using the text book, which show a lack of understanding of such text book.

Polymer‐Based Nano/Composites: Theory, Synthesis, Modifications, and Properties

1Department of Physics and Astronomy, The University of Texas Rio Grande Valley, 1201 W. University Drive, Edinburg, TX 78539, USA 2Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong 3Department of Materials Science, Faculty of Engineering, Tarbiat Modares University, Tehran, Iran 4Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico (UNAM), Cuernavaca, MOR, Mexico 5Centre for Advanced Materials and Performance Textiles, RMIT University, Room 8, Building 512, 25 Dawson Street, Brunswick, VIC 3056, Australia

Homologías nocionales en la resignificación de los conceptos formación-competencia: repercusiones en la educación universitaria

&lt;p align="justify"&gt;El presente texto es un esfuerzo por explorar limitaciones y posi- 163 bilidades de los conceptos &lt;em&gt;formación-competencia&lt;/em&gt; desde el caso concreto de la Universidad Nacional Autónoma de México, institución que a finales de los años noventa entró en crisis coyuntural de sentidos (tradicionalista-modernista) donde confluyeron horizontes interpretativos diversos sobre esos conceptos. Aquí se presentan dos apartados vinculados por un tema común: la conjunción formación-competencia a través de una interpretación específica de la educación dentro de un marco conceptual humanístico. Tales apartados son: 1) indagación conceptual para delimitar el sentido formación-competencia en el espectro semántico que despliega el concepto &lt;em&gt;universidad&lt;/em&gt; y 2) planteamientos para el esbozo de algunas opciones para el empleo de competencias en la formación universitaria.&lt;/p&gt;

Identification of calcified atheromatous plaques from patients attending a dental clinic unit in León, México

Atherosclerosis is a chronic inflammatory process that affects the arteries of different vascular beds. The most common site is the origin of the internal carotid. It is estimated that 50% of strokes are caused by atherosclerotic plaques. Panoramic radiographs are routine and inexpensive radiographic studies that allow us to observe flatly dental structures, maxillary and mandibular. Friendlander in 1981 published for the first time the possibility of identifying through panoramic radiographs atherosclerotic plaques calcified at this bifurcation giving importance of this study the opportunity for early detection of this disease. Objective: To determine the prevalence of carotid calcifications in 316 patients admitted to clinic admission of the Escuela Nacional de Estudios Superiores, Unidad Leon, Universidad Nacional Autonoma de Mexico (UNAM). Results: Consistent findings were obtained with atheroma calcified carotid in 7 patients with which it is concluded on the importance of training of imaging diagnosis undergraduates for early diagnosis and prevention of stroke in patients at risk of stroke.

Aportes de la teoría de la equilibración para el análisis de modalidades educativas en línea

En el presente reporte de investigación y como parte de la tesis que estoy realizando dentro del doctorado en Ciencias y Humanidades para el Desarrollo Interdisciplinario que ofertan la Universidad Autónoma de Coahuila y la Universidad Nacional Autónoma de México, a continuación refiero cómo he configurado desde la investigación interdisciplinaria, los Sistemas Sociales Complejos y la Epistemología Genética, el componente psico-cognitivo de mi unidad de análisis para la evaluación de los procesos cognoscitivos por los que cursan profesores y estudiantes que usan distintos recursos, soportes, herramientas o dispositivos que proveen las tecnologías de la información y comunicación, para los procesos de enseñanza y aprendizaje en línea de la modalidad semiescolarizada de la Benemérita Universidad Autónoma de Puebla.

Introduction of Gerardo Pérez-Ponce de León, recipient of the 2014 Clark P. Read Mentor Award.

Introduction of Gerardo Pérez-Ponce de León, recipient of the 2014 Clark P. Read Mentor Award.

Satisfacción con la residencia de Cirugía Pediátrica en México: Resultados de una encuesta de opinión

Much is known with regard to education and conformity of residents of all medical surgical disciplines, particularly since the implementation of the Plan Unico de Especializaciones Medicas. However, for pediatric surgeon little has been investigated. Objective: To evaluate the opinion of recently graduated pediatric surgeons with respect to the institution where they were formed, their teachers, their evaluation processes and themselves. Methods: A questionnaire was given to recently graduated pediatric surgeons in order to obtain information about the institutions where they were trained, their teachers, and evaluations of themselves. Results. Universidad Nacional Autonoma de Mexico and the Instituto Politecnico Nacional had the highest number of graduates the highest college grades average. Slightly over half of them said their training was excellent as residents. However 18 of the total reported that they lacked training in some disciplines. Conclusions. Even with some contradictions, the most valuable finding of the study was the need to promote interchanges with rotations in other institutions.

Efecto de un curso-taller de formación docente sobre los referentes pedagógicos de profesores de Embriología

IntroductionThe Faculty of Medicine of the Universidad Nacional Autónoma de México (UNAM) is currently working with the 2010 Curriculum for students admitted into the Bachelor of the Medicine program, which promotes the development of eight competencies in students. Indeed, educational systems depend on the quality and performance of their teachers, thus their training must be aimed at strengthening aspects that have an impact on the diversification of teaching strategies of pedagogical models. ObjectiveTo identify changes in the pedagogical models of teachers after attending the “Competency-Based Education Teacher Training Workshop Course”. MethodAn observational, descriptive, prospective and longitudinal study. The study population consisted of 24 teacher assistants who taught Human Embryology during the school year 2012-2013. The course was held for 30 hours. A questionnaire of pedagogical models comprised of 42 items with Likert scale and Cronbach’s alpha of 0.77 was applied before and after this course. The items were grouped into five strategies: learning, planning, methodology, assessment and teacher-student relationship. ResultsThe 17% and 10% of teachers who agreed with the traditional model on learning and planning strategies, respectively, showed a change towards alternative and educational technology models after attending the course. It should be noted that after the course, most of the teachers agreed with the traditional model in regards to the teacher-student relationship. ConclusionWe found that some teachers keep beliefs related to the traditional model in the methodology, assessing and teacher-student relationship before and after the workshop course.It is necessary that teaching training workshops include a wide variety of teaching strategies that consider the use of technology as a teaching tool, as well as different assessing processes/procedures that better fit the institutional educational context.

Reintroduction of the Scarlet Macaw (Ara Macao Cyanoptera) in the Tropical Rainforests of Palenque, Mexico: Project Design and First Year Progress

There are 17 extant species of macaws in the Neotropics, most of them found in South America. Two subspecies of scarlet macaw ( Ara macao) are distinguished in Mesoamerica: Ara macao cyanoptera, from Mexico to central Nicaragua, and Ara macao macao, from southern Nicaragua to South America. Habitat loss, hunting, and in particular illegal traffic have resulted in the local and regional extinction of this macaw within its historical range. In Mexico, the scarlet macaw has disappeared from about 98% of its indigenous range; it is extinct in El Salvador and occurs in very low numbers in Guatemala, Belize, Honduras, and Nicaragua. The IUCN recommends two tactics for population restoration: Reintroduction and Reinforcement. In this paper we report the design and first-year progress of a project to reintroduce the scarlet macaw ( A. macao cyanoptera) in the tropical rainforests of Palenque, Mexico, where this macaw has been extinct for more than 70 years. The project is spearheaded by Aluxes Ecopark Palenque, bringing together Xcaret Ecopark (as donor of captive-bred scarlet macaws) and the Institute of Biology of Universidad Nacional Autonoma de Mexico (UNAM; provider of the scientific platform for the project). The design of the project adheres to the IUCN/SSC guidelines for reintroductions. A soft-release protocol was developed as a major axis of the reintroduction of the scarlet macaw. This includes a preparation phase to enhance survival in the wild and a long-term post-release monitoring program. Broad social support was considered essential for the success of the project, and a program was implemented to include the local inhabitants as partners in this initiative. Between April 2013 and June 2014, we conducted six successful releases of a total of 92 macaws. Survival to August 2014 was 92%. The reintroduction of the scarlet macaw in the tropical rainforests of Palenque will restore a seed- and fruit-eating avian species with important consequences for ecosystem functions and processes, in a project that reconnects people with their natural heritage.

“Nacimiento de la pasión que se busca en el núcleo de su vida’’. Aproximaciones al sufismo desde un poemario de Francisco Magaña

In 1992, Francisco Magana published his third book of poems Calendas, laMirada, under the collection “El ala de tigre” of the Universidad Nacional Autonoma de Mexico. Nostalgia for a past time is suggested from the titleand is reinforced by the opening epigraph, which belongs to the Persian mysticalpoet Jalal al-Din Rumi: “Estuvimos en el cielo, eramos amigos / de losangeles; Padre, dejanos / regresar alli, pues esa es nuestra / tierra”. In thisbook, there are many intertexts and hypertexts referring to typical themes ofSufism. The call to contemplation, the relation between music and dance, theimages of sama, childhood and love as a path of union with the divine aresome of the more recurrent topics in this book, in which the Tabascan poet, rather than participating in a sufi mystical experience, amazed, writes abouthis discovery of this tradition.

Solar absorption infrared spectroscopic measurements over Mexico City: Methane enhancements

In this work, the experiment for performing solar-absorption infrared measurements from the atmospheric observatory of the Universidad Nacional Autónoma de México (UNAM) located at the university campus in Mexico City is described. The Fourier transform infrared (FTIR) spectrometer and solar-tracking system have been operating since June 2010, and from the recorded spectra the total column amounts of several atmospheric gases can be derived. The current study presents the results obtained for methane (CH4), an important pollutant involved in ozone production and a rapidly increasing greenhouse gas. The total column amounts, retrieved with high temporal resolution, present a large dispersion and day-to-day variability. A mean value of 2.88 × 1019 molecules/cm2 (1.829 ppm), with a 95% confidence interval between 2.62 and 3.14 × 1019 molecules/cm2, has been obtained for the period from June 2010 to December 2011. No clear annual cycle can be determined from the monthly means due to the large variability in the measurements, suggesting a significant effect of local emissions on the natural background concentrations. Some days with extraordinary enhancements are presented and a simple back trajectory analysis points to a predominant source direction from the northeast of the measurement site. The methane-contaminated air masses passing over the UNAM atmospheric observatory, however, originate presumably not from one but several dispersed sources. A more detailed analysis with modeling of the dynamics of these air masses is required.

Renewable energy research progress in Mexico: A review

Mexico ranks 9th in the world in crude oil reserves, 4th in natural gas reserves in America and it is also highly rich in renewable energy sources (solar, wind, biomasss, hydropower and geothermal). However, the potential of this type of energy has not been fully exploited. Hydropower is the renewable energy source with the highest installed capacity within the country (11,603 MW), while geothermal power capacity (958 MW) makes Mexico to be ranked 4th in the use of this energy worldwide. Wind energy potential is concentrated in five different zones, mainly in the state of Oaxaca, and solar energy has a high potential due to Mexico's ideal location in the so called Solar Belt. Biomass energy has the highest potential (2635 to 3771 PJ/year) and has been the subject of the highest number of research publications in the country during the last 30 years (1982–2012). Universidad Nacional Autonoma de Mexico has led research publications in hydropower, wind, solar and biomass energy and Instituto de Investigaciones Electricas in geothermal energy during this period. According to the General Law for Climate Change the country has set the goal of generating 35% of its energy needs from renewable sources by 2024. This paper presents an overview of the renewable energy options available in Mexico, current status, main positive results to date and future potential. It also analyses barriers hindering improvements and proposes pertinent solutions.

Perfil de ingreso de los alumnos de Enfermería, Facultades de Estudios Superiores Iztacala y Zaragoza, UNAM

Introduction: The University has as one of its tasks to better know the profiles and trajectories of students, so that supporting innovative and functional policies can be designed and implemented. Objective: To analyze the profile of students enrolling into the Nursing Undergraduate System at the Iztacala and Zaragoza Superior Studies Faculty. Method: Basic-descriptive study with freshmen students of the 2011-I generation of the Nursing Bachelors Degree program at the FES Zaragoza and Iztacala. the population was 600 alumni. A questionnaire was used to gather data. the instrument reliability was equivalent to a 0.875 Cronbach Alpha score. A SPSS ® database was created and data were analyzed through descriptive statistics. Results: the 49% of the students came from the “automatic pass” format. the enrollment grade point average went from 8.1 to 9.0. For the 61% of the students, nursing was their first choice of major. the socioeconomic level of the students was low. the 76% of the students obtained a grade point average between 8.0 and 10.0 during all their freshman year. Discussion: unlike other careers at the Universidad Nacional Autónoma de México (UNAM), Nursing accepts almost 50% of the prospects from external schools, situation which does not occur in other careers. Although the majority of students who entered have a low social-economical level, they have other favorable characteristics for their school trajectory such as a good grade point average and that they were accepted in the career that they chose.

Three new species ofGraphis(Ascomycota:Ostropales:Graphidaceae) from Mexico, with updates to taxonomic key entries for 41 species described between 2009 and 2013

AbstractThree species ofGraphis(Graphidaceae) are described from Mexico from two research stations of the Universidad Nacional Autónoma de México (UNAM): Chamela Biological Station in the Cuixmala-Chamela Biosphere Reserve, Jalisco, and Los Tuxtlas Tropical Biological Station in the Los Tuxtlas Biosphere Reserve, Veracruz. The new speciesGraphis bungartziiBarcenas-Peña, Lücking, Herrera-Campos &amp; R. Miranda is characterized by erumpent lirellae with a lateral thalline margin, striate labia and laterally carbonized exciple, transversely septate ascospores, and norstictic and connorstictic acids.Graphis chamelensisBarcenas-Peña &amp; Lücking has prominent lirellae with a basal to lateral thalline margin, entire labia and completely carbonized exciple, transversely septate ascospores, and norstictic acid. Finally,Graphis rosae-emiliaeBarcenas-Peña &amp; Lücking is characterized by erumpent lirellae with lateral thalline margin, striate labia and completely carbonized exciple, transversely septate ascospores, and no substances detected by TLC. We present updates to the world key toGraphisfor 41 newly described or reinstated species since the world key was published in 2009. The following new combination is proposed:Pallidogramme parvicarpum(B. O. Sharma &amp; Khadilkar) Lücking comb. nov., based onGraphis parvicarpaB. O. Sharma &amp; Khadilkar.

Control, Analysis, and Modeling of Vehicular Systems

1 Institute for Scientific and Technological Research of San Luis Potosi (IPICyT), Camino a la Presa San Jose 2055, Col. Lomas 4ta, 78216 San Luis Potosi, SLP, Mexico 2Department of Electrical and Computer Engineering, Concordia University, Montreal, QC, Canada H4G 2M1 3 Electrical Engineering Department, University of Texas at Arlington, Arlington, TX 76019, USA 4 Institute of Engineering, Universidad Nacional Autonoma de Mexico, 04510 Mexico City, DF, Mexico

Remembering William Carlos Williams: Hugo Rodríguez Alcalá (1917–2007)

Remembering William Carlos Williams:Hugo Rodríguez Alcalá (1917–2007) Paul Mariani On Tuesday afternoon, April 22, 1958, three men, two in their early forties, the third ten years younger, knocked on the front door of William Carlos Williams’s Victorian home at 9 Ridge Road in Rutherford, New Jersey, where the Williamses had lived for the past forty-six years. They were there to talk with Williams about a group of some twelve early and mid-twentieth century poems he had agreed to translate from the Spanish into a contemporary American idiom. The oldest of the three was José Vázquez Amaral, 44, a professor of Romance languages at Rutgers, where he had been teaching for the past eleven years. He was also a well-known member of Ezra Pound’s Ezraversity which held its peripatetic classes on the grounds of St. Elizabeths Hospital for the Criminally Insane in Washington, DC. It was there that Pound had spent the past twelve and a half years for his wartime radio broadcasts from Rome, often excoriating the American banking system and the FDR administration (once telling Williams in a letter that Roosevelt was nothing if not “an ambulating dunghill”).1 Over the past eight years, the handsome, genial Amaral had become a regular visitor of Pound’s at the hospital and had already translated Pound’s Pisan Cantos into Spanish. (He would translate and publish all 120 Cantos as Cantares Completos into Spanish three years after Pound’s death). Amaral had been born in Los Reyes, Jalisco, Mexico, and had earned degrees from La Universidad Nacional Autonoma de Mexico, including a law degree. Back in December 1951, Pound had sent Amaral an “anonymous communication” telling him to get in touch with Dr. W. Carlos Williams at his home in Rutherford. Pound had described Williams as “an honest man, who has spent most of his life in Rutherford.” Moreover, he was “part spanish, and has for 50 years been meaning to translate MORE spanish [End Page 1] poetry into north-american.” Amaral would do well, he added, “to call on him, and Old Bill might help stir up some enthusiasm at Rutgers” for greater respect shown to Iberian languages and literatures, in particular Latin American. Earlier Amaral had taught a seminar at Swarthmore on Spanish American poetry, and had done some translations into English “of Neruda, Villaurrutia, Carlos Pellicer and Jose Gorostiza,” which the translator Dudley Fitts had thought “rather good.”2 He wondered if Dr. Williams would be interested in seeing them, and of course Williams was. Pound, Amaral added, quoting Williams, was surely “one of the very few products of American, especially US, culture of sufficient stature to interest anyone.”3 The trouble was that the authorities were keeping Pound “in a cage in Washington” so as not to let him “mingle with other U. S. bipeds,” a fact which “baffled and confused” his Mexican sensibilities a great deal. In any event, he did think it “would be a fruitful thing to me” if he and Williams were “to become acquainted,” even “on the slightest pretext.”4 Four years later, on February 1, 1956, Amaral sent Williams a sheaf of poems by various Latin American poets, explaining that “the work of cultural interpenetration between English and Spanish America seems to have arrived.”5 Finally, in the spring of 1958, Amaral received a Rockefeller Foundation grant which allowed him to put into action the plan he had been devising, one of whose chief objectives, as he wrote Williams on April 17, 1958, was “to encourage translations from Latin American literature by eminently qualified people like yourself.” Only in this way, Amaral felt, could “the cause of better knowledge of Latin American literature” be properly served. As part of his larger project, Amaral was editing a Latin American number for New World Writing, in which Williams’s translations would appear. Earlier he’d sent Williams a dozen Spanish poems, along with literal translations he himself had made “to save [Williams] some useless trouble.”6 Now it would be Williams’ job was to turn them into poems. “I have been handed a job which I let myself in for without suspecting how...