Waveplate retarders based on overhead transparencies

We describe procedures for constructing inexpensive waveplates of desired retardation out of ordinary commercially available transparencies. Various relevant properties of the transparencies are investigated: the dependence of retardation on rotation of the film, tilt, wavelength, position, and temperature. Constructing waveplates out of combinations of transparency sheets is also explored.Comment: 7 pages, 12 fig

CIXL2: A Crossover Operator for Evolutionary Algorithms Based on Population Features

In this paper we propose a crossover operator for evolutionary algorithms with real values that is based on the statistical theory of population distributions. The operator is based on the theoretical distribution of the values of the genes of the best individuals in the population. The proposed operator takes into account the localization and dispersion features of the best individuals of the population with the objective that these features would be inherited by the offspring. Our aim is the optimization of the balance between exploration and exploitation in the search process. In order to test the efficiency and robustness of this crossover, we have used a set of functions to be optimized with regard to different criteria, such as, multimodality, separability, regularity and epistasis. With this set of functions we can extract conclusions in function of the problem at hand. We analyze the results using ANOVA and multiple comparison statistical tests. As an example of how our crossover can be used to solve artificial intelligence problems, we have applied the proposed model to the problem of obtaining the weight of each network in a ensemble of neural networks. The results obtained are above the performance of standard methods

Square-free class sizes in products of groups

We obtain some structural properties of a factorised group $G = AB$, given that the conjugacy class sizes of certain elements in $A\cup B$ are not divisible by $p^2$, for some prime $p$. The case when $G = AB$ is a mutually permutable product is especially considered

Petroleum in the Spanish Iberian Peninsula

The main events of the history of petroleum in Spain are the following: 1) The mining concession of petroleum named El Progreso is the first one in Spain and occurred only seven years after Edwin Drake (1819-1880) drilled the first oil well in Pennsylvania. 2) The first survey of oil production in Spain, well known as the Tejon borehole, was conducted by the Sondeos de Huidobro Company in 1900, in Huidobro (Burgos), and reached 501 m of depth. 3) In 1964 CAMPSA and AMOSPAIN found petroleum in the Ayoluengo field (Burgos), with a borehole of 1,349 m of depth. This was the first and only petroleum field in the continental Spain in this zone. The Ayoluengo petroleum field has been active during 35 years. In this paper we will review the history of petroleum in peninsular Spain

Information about petroleum in America prior to the nineteenth Century

The petroleum substances have been used a lot of centuries ago: bitumen has been used in Neolithic Period to fix head's hammer of stone and to set beads. The authors of this paper want to show the knowledge of bitumen and asphalt in South America until the 19t h century through documents of Spaniards conquerors. Besides, we have done a comparative study between different words to design these petroleum product

Perspectivas curriculares y uso didáctico de la modelación en educación matemática

En Relme 15, comieza a gestarse la realización de actividades de modelación lo cual se evidencia en hechos como el curso breve denominado “Ecuaciones Diferenciales con Aplicaciones” (Martínez Luaces, 2002). Algunos de los problemas considerados en dicho curso fueron: a) Cinética: Adsorción de COB2B sobre superficie facetada de platino, b) Mezclas y tanques: Sistema con tres tanques interconectados, c) Transferencia de masa: Difusión de glucosa en una cereza y d) Transferencia de masa: Secado de un vegetal por las caras. Con el abordaje de cada situación se logró acercar a los docentes a los problemas de modelado vinculados a otras asignaturas o situaciones del mundo real. Aunque esto por si solo no garantiza cambios sustantivos en la práctica docente, ya que “modelar es un modo de vivir” Houston (2001). Esto significa que se requiere generar las condiciones para que el cambio sea posible. Y este grupo de trabajo pretende coadyuvar en tan impostergable tarea

Spatial spillovers in public expenditure on a municipal level in Spain

A key function of local governments is to provide a wide array of public services. The supply of these services has been found to create spatial spillovers among neighbouring municipalities. Although it is generally agreed that spillovers are present in models that explain government expenditures, their type—whether endogenous, exogenous or residual—and sign—whether positive or negative—remain ambiguous. In most cases, a subjective process is used to select the type of spatial regression model used in analysis, with mixed results. Per capita expenditures of ten subprogrammes (Security, Housing, Welfare, Environment, Social services, Employment promotion, Health, Education, Culture and Sport) are analysed for all Spanish municipalities with more than 5000 inhabitants in the 2010–2012 period. A Spatial Seemingly Unrelated Regression methodology in a panel framework is used to incorporate correlation between different subprogrammes and spatial dependence. Our results show that the three types of spatial effects are present. Furthermore, substantive dependence is positive in most cases, while negative residual dependence is observed in some.We gratefully acknowledge the contribution of three anonymous reviewers in helping us improve the quality of this paper. Prof. Fernando A. López , grateful for the financial support offered by the projects from Programa de Ayudas a Grupos de Excelencia de la Región de Murcia, Fundación Seneca (#19884-GERM-15) and Ministry of Economy and Competiveness (ECO2015-651758)

MT1a mRNA Expression in Human Lung Cells (BEAS 2B) After Airborne PM10 and Copper Exposure: A Possible Biomarker for Asthma

Puerto Ricans have the highest prevalence, morbidity and mortality of asthma than any other ethnic group in the U.S. and can be triggered by different stimuli such as airborne Particle pollution (PM). PM transfers transition metals, including cooper, to the human airways generating reactive oxygen species (ROS). Metallothionein protein (MT1A) is a free radical scavenger expected to be induced in lung cells by PM exposure; however, this has never been proven nor demonstrated. The hypothesis involves the amounts of PM10 in 2004, which would be significantly higher in the urban sites during months of March and June, thereby increasing PM metal exposure and inducing MT1A gene at the urban site. PM10 filters for Urban (Guaynabo) and rural (Fajardo) site were provided by the PREQB. Organic extracts were prepared from filters by means of Soxhlet Extraction and heavy metals were determined using Atomic Absorption Spectrometry. BEAS-2B cells were cultured and exposed to PM10 during 4 hrs. RNA was isolated and relative mRNA levels of MT1A were determined by RT-PCR. Urban PM10 concentrations were 35 ug/m3 and 60ug/m3 for the months of March and June, respectively. Concentrations of copper for this urban PM10 were 29.6 ppm and 50.3 ppm, for March and June, respectively. Exposure to Cu leads to an MT1A expression in lung cells demonstrating its response to metal exposure. Cellular response for the mRNA expression of MT1A was greater in relative high inflammation markers than in PM10 samples

Social Transformation From Participation In Community Media

Estamos en un contexto en el que cada vez tenemos más facilidades para que la ciudadanía participe en los medios de comunicación; sin embargo, estas oportunidades no han conseguido cambiar el paradigma de los medios tradicionales en favor de un modelo comunicativo horizontal y participativo. De hecho, todavía mucha gente sigue sin conocer en qué consisten las experiencias comunicativas comunitarias. Por ese motivo, queremos conocer estas experiencias y estudiar los efectos personales y sociales que provoca implicarse en un proceso de este tipo a través de la narración de las historias de vida de sus participantes. Hasta ahora, la mayor parte de los entrevistados ha reconocido un aprendizaje, una transformación personal y en cierta medida, también social. Sin embargo, los resultados no son muchas veces los esperados, y los entrevistados reflexionan sobre los problemas y dificultades de los medios comunitarios.We are in a context where we have more facilities for citizenship participate in community media; however, these opportunities haven’t achieve to change traditional media model in favor of one more horizontal and participatory. In fact, there are a lot of people don’t know what are the communicative community experiences. For this reason, we want to know these experiences and to study the personal and social effect, that cause involvement in a this kind of experience, from the narration of the life stories of its participants. Until now, the most of the interviewees have recognized an important learning, a personal transformation and in some measure, also social. Although the results are not often as expected, they reflect on their problems in order to achieve the objectives set as community media.Ministerio de Economía y Competitividad CSO2016-78386-