5,811 research outputs found
Analysis of the Earthquake-Resistant Design Approach for Buildings in Mexico
The development of new codes for earthquake-resistant structures has made possible to guarantee a better performance of buildings, when they are subjected to seismic actions. Therefore, it is convenient that current codes for design of building become conceptually transparent when defining the strength modification factors and assessing maximum lateral displacements, so that the design process can be clearly understood by structural engineers. The aim of this study is to analyze the transparency of earthquake-resistant design approach for buildings in Mexico by means of a critical review of the factors for strength modification and displacement amplification. The approach of building design codes in US is also analyzed. It is concluded that earthquake-resistant design in Mexico have evolved in refinement and complexity. It is also demonstrated that the procedure prescribed by such design codes allows the assessment of the design strengths and displacements in a more rational way, in accordance not only with the present stage of knowledge but also with the contemporary tendencies in building codes. In contrast, the procedures used in US codes may not provide a clear view for seismic response assessment of buildings
Analysis of Moon impact flashes detected during the 2012 and 2013 Perseids
We present the results of our Moon impact flashes detection campaigns
performed around the maximum activity period of the Perseid meteor shower in
2012 and 2013. Just one flash produced by a Perseid meteoroid was detected in
2012 because of very unfavourable geometric conditions, but 12 of these were
confirmed in 2013. The visual magnitude of the flashes ranged between 6.6 and
9.3. A luminous efficiency of 1.8 10 has been estimated for
meteoroids from this stream. According to this value, impactor masses would
range between 1.9 and 190 g. In addition, we propose a criterion to establish,
from a statistical point of view, the likely origin of impact flashes recorded
on the lunar surface.Comment: Accepted for publication in Astronomy and Astrophysics on March 11,
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Diseño de un edificio multifamiliar a base de un sistema constructivo mixto de ferrocemento y concreto, ubicado en el Departamento de Managua-Sabana Grande
Como propósito de esta investigación, se presenta el ferrocemento como un sistema constructivo para un edificio de vivienda multifamiliar, el cual muestra un buen comportamiento sÃsmico de forma que constituya una solución resistente, digna, sostenible, segura y de bajo cost
Prenatal ethanol exposure modifies locomotor activity and induces selective changes in Met-Enkephalin content in adolescent rats
Prenatal ethanol exposure (PEE) facilitates alcohol acceptance and intake, suggesting that ethanol in uteromay increase the probability of drug abuse during adolescence and adulthood. Alcohol reinforcement involves the ethanol-induced activation of opioidergic systems in mesocorticolimbic areas. Changes in opioidneurotransmission may be relevant during ethanol intoxication, as well as in the adaptive neural responsesinduced by the drug. Some studies have assessed the possible changes in opioidergic systems as a functionof ethanol exposure in adolescent animals. However, PEE effects upon locomotive responses elicited by anethanol challenge and modulation of neurotransmission of opioidergic systems remain to be understood. Thiswork assessed the susceptibility of adolescent rats to prenatal and/or postnatal ethanol exposure in terms oflocomotive responses, as well as alcohol-related effects on Methionine-enkephalin (Met-enk) expression inbrain areas related to drug reinforcement. Pregnant rats received a daily intragastric administration of ethanol(2 g/kg) or water, during gestational days 17-20. Adolescents at postnatal day 30 (PD30) were tested in afirst baseline trial (habituation session) and evaluated in terms of spontaneous activity. Thereafter, animalsreceived an ip injection of vehicle (saline 0.9% w/v) (vehicle session) and were immediately evaluated interms of activity during 30 min. After this second trial, animals from both prenatal treatments were injectedwith ethanol (1.0 g/kg ip) or saline, and locomotor activity was immediately assessed for 30 min (drug session). Met-enk content was quantitated by radioimmunoassay in several brain regions: ventral tegmental area[VTA], nucleus accumbens [NAcc], prefrontal cortex [PFC], substantia nigra [SN], caudate-putamen [CP],amygdala, hypothalamus and hippocampus. PEE significantly reduced rearing responses. Ethanol challenge atPD30 decreased horizontal locomotion and showed a tendency to reduce rearings and stereotyped behaviors.PEE increased Met-enk content in the PFC, CP, hypothalamus and hippocampus, but did not alter peptidelevels in the amygdala, VTA and NAcc. These findings suggest that PEE selectively modifies behavioralparameters at PD30 and induces specific changes in Met-enk content in regions of the mesocortical andnigrostriatal pathways, the hypothalamus and hippocampus. Prenatal and postnatal ethanol actions on motoractivity in adolescents could involve activation of specific neural enkephalinergic pathways.Fil: Méndez Ubach, Milagros. Instituto Nacional de PsiquiatrÃa Ramón de la Fuente; MéxicoFil: Hernández Fonseca, Karla. Instituto Nacional de PsiquiatrÃa Ramón de la Fuente; MéxicoFil: Abate, Paula. Universidad Nacional de Córdoba. Instituto de Investigaciones Psicológicas. - Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Psicológicas; Argentina. Universidad Nacional de Córdoba. Facultad de PsicologÃa; ArgentinaIX International Meeting of the Latin American Society for Biomedical Research on Alcoholism: Determinants of Alcoholism: Bridging the gap between epidemiological and basic researchCórdobaArgentinaLatin American Society for Biomedical Research on Alcoholis
Cumplimiento del protocolo de preeclampsia del servicio de maternidad del Hospital Alemán Nicaragüense, Enero-Diciembre 2015
Se realizó un estudio con el objetivo de determinar el cumplimiento del protocolo de Preeclampsia del personal de salud en el Servicio de Maternidad del Hospital Alemán Nicaragüense, Enero - Diciembre 2015. El presente estudio es de tipo descriptivo, de corte transversal, con una muestra constituida por81 pacientes, de las cuales 7 presentaron diagnóstico de preeclampsia moderada y 74 pacientes con preeclampsia grave. Como criterios de inclusión se tomaron en cuenta los expedientes clÃnicos con información completa y disponible en el servicio de estadÃstica, pacientes ingresadas con diagnóstico de Hipertensión Gestacional pero que evolucionaron a Preeclampsia en cualquiera de sus dos entidades y pacientes sin otra patologÃa agregada.
Entre los principales resultados se obtuvo que tanto para preeclampsia moderada como grave las principales caracterÃsticas sociodemográficas fueron, la edad predominante era entre 20-34 años. La procedencia de las pacientes fue en su totalidad urbana. La escolaridad fue principalmente secundaria incompleta y el estado civil de las pacientes fue en su mayorÃa unión libre.
El nivel de cumplimiento de protocolo tomando en cuenta criterios diagnósticos, medidas generales, tratamiento farmacológico, criterios de alta y control y seguimiento, se cumplió en 42.9% de las pacientes con preeclampsia moderada y en preeclampsia grave el nivel de cumplimiento de protocolo fue de 66.2%
Entrepreneurship in Costa Rica: Stagnation in the transition to innovation
Costa Rica está estancada en una fase de desarrollo de transición entre una economÃa basada en eficiencia y una tendiente a la innovación, sin promover adecuadamente las condiciones de emprendedurismo que le permitan llevar a cabo dicha transformación. Mientras tanto,otros paÃses de la región se ubican en mejor posición para fomentar emprendimientos de este tipo. Ante esta situación resulta importante cuestionarse,¿cuáles son las condiciones sobre emprendedurismo en Costa Rica que podrÃan mejorar la transición hacia una economÃa basa en la innovación? Para mejorar esta situación el paÃs debe desarrollar un programa de apoyo interinstitucional tendiente a generar atracción de inversión extranjera directa, encadenamientos productivos, mejorar el capital humano y los servicios de capacitación, incubación, aceleración y financiamiento, asà como la articulación de la polÃtica pública.Costa Rica is stuck in a transition phase between an efficiency-based economy and an innovation-based economy and is not promoting the necessary entrepreneurial conditions that would lead to the required transformation. Meanwhile, other countries in the region are in a better position to encourage entrepreneurship. In this situation, it is important to ask which are the conditions regarding entrepreneurship in Costa Rica that could improve the transition to an innovation-based economy. To improve this situation, the country must develop an interinstitutional support program that attracts direct foreign investment and linkages between businesses, improve human capital, provide training, incubation and funding, and have better articulation of public policy.UCR::Sedes Regionales::Sede de OccidenteUCR::VicerrectorÃa de Docencia::Ciencias Sociales::Facultad de Ciencias Económicas::Escuela de EconomÃ
La investigación escolar en la construcción de explicaciones acerca de la transmisión de caracteres hereditarios. sistematización de la unidad didáctica ¡moscas!... a enseñar herencia
El presente trabajo expondrá el desarrollo significativo respecto a conceptos, procedimientos y actitudes referidos a la herencia de caracteres hereditarios, que alcanzaron los estudiantes del grado octavo del IEDIT Rodrigo de Triana, en un periodo de tres meses en el año 2008, durante el cual se ejecutó el diseño, aplicación y sistematización de la unidad didáctica ¡Moscas! a enseñar herencia. En esta experiencia educativa se adoptaron los postulados del Enfoque de Enseñanza por Investigación Dirigida y el instrumento metodológico de Investigación Acción, donde los estudiantes organizados en equipos de trabajo abordaron una pregunta problema para desarrollar una investigación escolar, bajo la atenta dirección de las docentes, quienes corroboraron un cambio procedimental, conceptual y actitudinal en los estudiantes del grado 803
Building a Successful e-Learning Project in Higher Education
Internet has made our world, the way we live andeducate, more dynamic and virtual than ever, creating greaterchallenges and new possibilities. In this way, it is important thathigher education institutions have, as a priority, the goal offinding effective ways of providing new learning opportunitiesaccording to their environment: student characteristics; teachertraining; economic crisis and advancing technology in an effortto make learning more efficient, equitable and innovative. AtGuarda Polytechnic Institute, Portugal (IPG), we recognize theneeds and the opportunities to create and develop new eeducationcourses in order to engage and motivate students andteachers according to their needs. Thus, we have, in this lastdecade, developed and implemented a set of institutionalobjectives with regard to teaching electronic courses which aimto provide intuitive content online courses, easy to accessanywhere, any time. The main purpose of this paper is to presentour strategies as an institution, vision and goals when we talkabout electronic learning. We bring forward what we believe tobe extremely important and that must be considered when anorganization wants to implement and develop e-Learning. Thepaper also presents the outcomes and synthesizes the insightscollected since when we implemented a mobile learning solution.Findings indicate that building a successful e-learning projectdepends basically on two components, teachers’ training andstudents’ characteristics. The focus attention on these twocomponents can create new, successful and powerfulopportunities of e-learning
Expresión proteica de p53 y proliferación celular en leucoplasias orales
Objetivos: Conocer la expresión proteica de las alteraciones
genéticas que se producen en las etapas precoces de la cancerización
del campo de cavidad oral en nuestro medio. Estudiar
la proliferación celular mediante Ki-67 y la expresión de la
proteÃna p53 para valorar si las alteraciones en la expresión
proteica de estos marcadores suceden de forma secuencial a
través de las distintas etapas en la cancerización del campo de
la cavidad oral.
Material y métodos: Se realizó un estudio mediante técnicas de
inmunohistoquÃmica sobre 53 pacientes que presentaron lesiones
de leucoplasia oral, atendidos por el Servicio de O.R.L del
Hospital Universitario de Salamanca, desde 1.990 hasta 2000.
Se incluyen en el estudio 11 muestras de epitelio normal, 15
displasias leves y moderadas, 15 carcinomas in situ, y 12 carcinomas
microinvasores. Resultados: Encontramos la proliferación
celular aumentada y sobreexpresión de p53 a medida que avanzamos
en el grado de severidad histopatológica de las lesiones.
Las alteraciones más precoces son el aumento significativo de
la proliferación celular en displasias leves y moderadas y el
aumento de expresión de p53.
Conclusión: La leucoplasia oral es un estado precanceroso que
constituye una lesión cancerizable debido a las alteraciones genéticas
que intervienen en la evolución de la lesión. El estudio
inmunohistoquÃmico y molecular de las lesiones es un medio rutinario
que permite conocer la expresión proteica de las alteraciones
genéticas, que puede ayudar en el diagnóstico precoz y tratamiento
de esta patologÃa, teniendo especial relevancia el estudio de Ki-67
en etapas iniciales y p53 en lesiones más avanzadas.OBJECTIVES: We intend to know the protein expression of
genetic alterations that take place in the early stages in the field
cancerization of oral cavity in our means as well as to study the
cellular proliferation by means of Ki-67 and the protein product
expression of p53 to value if the alterations in the protein
products expression of these markers happen in a sequential
pathway through the different stages in the field cancerization
of oral cavity.
MATERIALS AND METHODS: A study was made by immunohistochemistry
on 53 patients that presented lesions of oral
leukoplaquia, assisted by the ENT service at University Hospital
of Salamanca, from 1.990 up to 2000. 11 samples of normal epithelium,
15 mild to moderate dysplasias, 15 in situ carcinomas
and 12 microinvasive carcinomas are included in the study.
RESULTS: we find an increased cellular proliferation and p53
over-expression as we advance in the grade of severity histopathologic
of these lesions. The most early alterations are a
significant increase of cell proliferation in mild and moderate
dysplasias and an increased p53 over-expression.
CONCLUSIONS: Oral leukoplaquia is a precancerous stage that constitutes a canzerisable lesion due to the genetic alterations
that mediate in the evolution of lesion. Routine Immunohistochemical
and molecular study of these lesions allow us to
know the protein expression of genetic alterations that can help
in the early diagnosis and treatment of this pathology, having
special relevance the study of Ki-67 in early stages and p53 in
advanced lesions
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