794 research outputs found
On the origin and early evolution of biological catalysis and other studies on chemical evolution
One of the lines of research in molecular evolution which we have developed for the past three years is related to the experimental and theoretical study of the origin and early evolution of biological catalysis. In an attempt to understand the nature of the first peptidic catalysts and coenzymes, we have achieved the non-enzymatic synthesis of the coenzymes ADPG, GDPG, and CDP-ethanolamine, under conditions considered to have been prevalent on the primitive Earth. We have also accomplished the prebiotic synthesis of histidine, as well as histidyl-histidine, and we have measured the enhancing effects of this catalytic dipeptide on the dephosphorylation of deoxyribonucleotide monophosphates, the hydrolysis of oligo A, and the oligomerization 2', 3' cAMP. We reviewed and further developed the hypothesis that RNA preceded double stranded DNA molecules as a reservoir of cellular genetic information. This led us to undertake the study of extant RNA polymerases in an attempt to discover vestigial sequences preserved from early Archean times. In addition, we continued our studies of on the chemical evolution of organic compounds in the solar system and beyond
On the Theory of Evolution Versus the Concept of Evolution: Three Observations
Here we address three misconceptions stated by Rice et al. in their observations of our article Paz-y-Miño and Espinosa (Evo Edu Outreach 2:655–675, 2009), published in this journal. The five authors titled their note “The Theory of Evolution is Not an Explanation for the Origin of Life.” First, we argue that it is fallacious to believe that because the formulation of the theory of evolution, as conceived in the 1800s, did not include an explanation for the origin of life, nor of the universe, the concept of evolution would not allow us to hypothesize the possible beginnings of life and its connections to the cosmos. Not only Stanley Miller’s experiments of 1953 led scientists to envision a continuum from the inorganic world to the origin and diversification of life, but also Darwin’s own writings of 1871. Second, to dismiss the notion of Rice et al. that evolution does not provide explanations concerning the universe or the cosmos, we identify compelling scientific discussions on the topics: Zaikowski et al. (Evo Edu Outreach 1:65–73, 2008), Krauss (Evo Edu Outreach 3:193–197, 2010), Peretó et al. (Orig Life Evol Biosph 39:395–406, 2009) and Follmann and Brownson (Naturwissenschaften 96:1265–1292, 2009). Third, although we acknowledge that the term Darwinism may not be inclusive of all new discoveries in evolution, and also that creationists and Intelligent Designers hijack the term to portray evolution as ideology, we demonstrate that there is no statistical evidence suggesting that the word Darwinism interferes with public acceptance of evolution, nor does the inclusion of the origin of life or the universe within the concept of evolution. We examine the epistemological and empirical distinction between the theory of evolution and the concept of evolution and conclude that, although the distinction is important, it should not compromise scientific logic
Should the teaching of biological evolution include the origin of life?
The development of mainstream research on the origin of life as an outcome of Darwinian evolution is discussed. It is argued that prebiotic evolution and the origin of life should not be excluded from the syllabus and should be part of classes on biological evolution, and that the transition from non-living to living matter is best understood when seen as part of evolutionary biology. The wide acceptance of evolutionary approaches to the study of the emergence of life in European and Latin American countries is discussed
Presentación: Covid 19 y Sociedad
It introduces the content of the monograph and highlights the efforts of the authors as well as their perspective of the pandemic and its social impact in three different countries.Introduce el contenido del monográfico y destaca el esfuerzo de los autores así como su perspectiva de la pandemia y su impacto social en tres países distintos
Egoístas y autómatas del capitalismo global
Capitalist globalization configures a new social order founded on selfish individualism. The free market establishes purposes and meanings of life that do not favor empathic and solidarity experiences among human beings. Throughout history there have been various cultural matrices and ego modeling, which have been determinants for social coexistence. Selfishness exalted by capitalist globalization leads to accumulation and disputes over material wealth. The global technical advance broadens the domain of some economic sectors over the rest of society. The increasing presence of automatons in everyday life causes the displacement of workers, invasion of privacy and the control of the expectations of demographic majorities. It is through the generalized questioning of the civilizing course that new and better perspectives of humanism may emerge in the present centuryLa globalización capitalista configura un nuevo orden social fundado en el individualismo egoísta. El libre mercado instaura propósitos y sentidos de vida que no favorecen las experiencias empáticas y solidarias entre los seres humanos. A lo largo de la historia han existido diversas matrices culturales y modelamientos del ego, que han sido determinantes para la convivencia social. El egoísmo exaltado por la globalización capitalista propicia acumulación y disputas por la riqueza material. El avance técnico a escala mundial amplia el dominio de algunos sectores económicos sobre el resto de la sociedad. La presencia creciente de autómatas en la vida cotidiana provoca el desplazamiento de trabajadores, invasión de la privacidad y el control de las expectativas de las mayorías demográficas. Es a través del cuestionamiento generalizado del rumbo civilizatorio que podrá emerger en el presente siglo nuevas y mejores perspectivas de humanism
Herpetofauna en dos sitios en el municipio de Soto la Marina, Tamaulipas, México
We conducted a herpetofaunal study from November 2009 to July 2010 on the ranches El Herradero and San Jose de los Leones, both in the municipality of Soto la Marina, in the centraleastern part of the state of Tamaulipas, northeastern Mexico. Their location corresponds to a peninsula surrounded by the Laguna Madre. The objectives were to conduct a herpetological inventory and to determine the distribution of the species in the plant communities and the status of each species following the criteria of the NOM-059-SEMARNAT-2010. The information will be useful in delineating an area to set aside for conservation easement for the species. We followed the transect method described by Campbell & Christman (1982). We recorded 17 species: one anuran, one crocodile, six turtles, three lizards and six snakes. Of these, eight are new records for the municipality of Soto la Marina, 10 species are at risk, six are of special concern, three are threatened, and one is endangered. The ranches contain 34.69% of the herpetofauna species present in the municipality.Se realizó un estudio herpetofaunístico en los ranchos El Herradero y San José de los Leones ambos ubicados en el municipio de Soto la Marina, en la porción central-oriental del estado de Tamaulipas al Noreste de México. Estos predios se ubican en una forma de península rodeada por agua perteneciente a la Laguna Madre. Los objetivos fueron: realizar un inventario herpetológico, determinar la asociación de la herpetofauna con las comunidades vegetales y determinar el estatus de cada una de las especies de acuerdo a la NOM-059-SEMARNAT-2010. Lo anterior con la finalidad de que el área ocupada por los ranchos sea para establecer sitios de conservación como servidumbre ecológica de especies. Se siguió el muestreo de transectos descrito por Campbell & Christman (1982). El estudio se realizó desde noviembre de 2009 hasta julio de 2010. Se registraron 17 especies: un anuro, seis tortugas, un cocodrilo, tres lagartijas y seis serpientes. De estos, ocho son nuevos reportes para el municipio de Soto la Marina, y de acuerdo con la NOM-059-SEMARNAT-2010 se reportaron 10 especies donde seis se encuentran Sujetas a Protección Especial, tres se encuentran Amenazadas y una en Peligro de Extinción. Los ranchos cuentan con 34.69% de las especies de herpetofauna presente en el municipio
Oil extraction and crude oil price behavior in the United States: a fractional integration and cointegration analysis.
This study reviews the relationship between the different types of oil extraction such as horizontal drilling or fracking, or directional drilling, which is a hybrid between vertical and horizontal, on the behavior of West Texas Intermediate crude oil prices. In doing so the study adds a new dimension to the literature on the relationship between oil price and extraction techniques. The analysis is based on statistical properties using the VAR model of Fractional Cointegration, reflecting evidence of cointegration between the series, and indicating a long-term equilibrium relationship. In addition, we apply the wavelet transform to analyze the structural changes in the price of West Texas Intermediate brought about by changes in drilling technology. Our results show that all three forms of extraction and West Texas Intermediate prices reach high levels of correlation, particularly around 2014. We conclude that a decrease in production based on any form of crude oil extraction leads to an increase in the price of crude oil.pre-print1097 K
Cultura de la legalidad ciudadana
La cultura de la legalidad es un conjunto de valores y acciones que genera en la ciudadanía la defensa de un Estado de derecho y el rechazo a la ilegalidad. Es a través de este mecanismo que la ciudadanía se autorregula, ya que son creencias compartidas regidas en forma democrática
Aprendizaje-Servicio y exclusión social. Una experiencia en Educación Infantil
Este trabajo fin de grado trata de la metodología de aprendizaje-servicio aplicado
en relación a las necesidades sociales que detectamos en el verano del 2014 en la
escuela de verano con niños, de entre 3 y 12 años, del barrio de Dos Hermanas que
padecen riesgo de exclusión social. Con la intención de ayudarles y atenderles hemos
desarrollado una programación didáctica.
Hemos profundizado en conceptos trabajados en las asignaturas del grado de
Educación Infantil como son la educación, las nuevas pedagogías o las necesidades
sociales, pero también hemos ampliado conocimientos teóricos en relación al
aprendizaje-servicio y su aplicación práctica. En concreto se ha realizado una
programación útil y realista para un grupo de niños de la etapa de educación infantil.
Tras la revisión de material bibliográfico tanto nacional como internacional, nos
hemos propuesto ofrecer una programación didáctica que en primer lugar cubra sus
necesidades alimenticias y de higiene de este grupo específico, y en un segundo lugar,
que les aporte un apoyo escolar acompañado de actividades lúdicas.
Hemos podido concluir lo importante que es ofrecer a todas las personas una
educación digna que pueda servir para asegurar una igualdad de oportunidades, y pueda
ayudar a estos niños a alcanzar su máximo desarrollo atendiendo a sus necesidades
personales, sociales y académicas. De este modo el aprendizaje-servicio se presenta
como una metodología útil para contribuir a solucionar las necesidades que presenta
este grupo en exclusión social
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