1,904 research outputs found

    Hydrogen bonds and asymmetrical heat diffusion in a-Helices. A Computational Analysis

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    In this work, we report the heat rectifying capability of a-helices. Using molecular dynamics simulations we show an increased thermal diffusivity in the C-Terminal to N-Terminal direction of propagation. The origin of this effect seems to be a function of the particular orientation of the hydrogen bonds stabilizing these a-helices. Our results may be relevant for the design of thermal rectification devices for materials science and lend support to the role of normal length hydrogen bonds in the asymmetrical energy flow in proteins

    Educators of Prospective Teachers Hesitate to Embrace Evolution due to Deficient Understanding of Science/Evolution and High Religiosity

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    Acceptance of evolution by educators of prospective teachers remains superficially studied despite their role in having mentored schoolteachers whose weak support of evolution is known. Here, we contrast the views of New England educators of prospective teachers (n = 62; 87% Ph.D./doctorate holders in 32 specializations) with those of the general faculty (n = 244; 93% Ph.D./doctorate holders in 40 disciplines), both members of 35 colleges and universities, and with college students (n = 827; subsample of the 35 institutions) who were polled on: (1) the controversy evolution vs. creationism vs. intelligent design (ID), (2) their understanding of how science/evolution works, and (3) their religiosity. The educators held intermediate positions in respect to the general faculty and the students: 94% of the general faculty, 75% of the educators, and 63% of the students said they accepted evolution openly; and 82% of the general faculty, 71% of the educators, and 58% of the students thought that evolution is definitely true. Only 3% of the general faculty in comparison to 19% of the educators and 24% of the students thought that evolution and creationism are in harmony. Although 93% of the general faculty, educators, and students knew that evolution relies on common ancestry, 26% of the general faculty, 45% of the educators, and 35% of the students did not know that humans are apes. Remarkably, 15% of the general faculty, 32% of the educators, and 35% of the students believed, incorrectly, that the origin of the human mind cannot be explained by evolution; and 30% of the general faculty, 59% of the educators, and 75% of the students were Lamarckian (=believed in inheritance of acquired traits). For science education: 96% of the general faculty, 86% of the educators, and 71% of the students supported the exclusive teaching of evolution, while 4% of the general faculty, 14% of the educators, and 29% of the students favored equal time to evolution, creationism and ID; note that 92% of the general faculty, 82% of the educators, and 50% of the students perceived ID as either not scientific and proposed to counter evolution based on false claims or as religious doctrine consistent with creationism. The general faculty was the most knowledgeable about science/evolution and the least religious (science index, SI = 2.49; evolution index, EI = 2.49; and religiosity index, RI = 0.49); the educators reached lower science/evolution but higher religiosity indexes than the general faculty (SI = 1.96, EI = 1.96, and RI = 0.83); and the students were the least knowledgeable about science/evolution and the most religious (SI = 1.80, EI = 1.60, and RI = 0.89). Understanding of science and evolution were inversely correlated with level of religiosity, and understanding of evolution increased with increasing science literacy. Interestingly, ≈36% of the general faculty, educators and students considered religion to be very important in their lives, and 17% of the general faculty, 34% of the educators, and 28% of the students said they prayed daily. Assessing the perception of evolution by educators of prospective teachers vs. the general faculty and the students of New England, one of the historically most progressive regions in the U.S., is crucial for determining the magnitude of the impact of creationism and ID on attitudes toward science, reason, and education in science

    New England Faculty and College Students Differ in Their Views about Evolution, Creationism, Intelligent Design, and Religiosity

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    Public acceptance of evolution in Northeastern U.S. is the highest nationwide, only 59%. Here, we compare perspectives about evolution, creationism, intelligent design (ID), and religiosity between highly educated New England faculty (n = 244; 90% Ph.D. holders in 40 disciplines at 35 colleges/universities) and college students from public secular (n = 161), private secular (n = 298), and religious (n = 185) institutions: 94/3% of the faculty vs. 64/14% of the students admitted to accepting evolution openly and/or privately, and 82/18% of the faculty vs. 58/42% of the students thought that evolution is definitely true or probably true, respectively. Only 3% of the faculty vs. 23% of the students thought that evolution and creationism are in harmony. Although 92% of faculty and students thought that evolution relies on common ancestry, one in every four faculty and one in every three students did not know that humans are apes; 15% of the faculty vs. 34% of the students believed, incorrectly, that the origin of the human mind cannot be explained by evolution, and 30% of the faculty vs. 72% of the students was Lamarckian (believed in inheritance of acquired traits). Notably, 91% of the faculty was very concerned (64%) or somehow concerned (27%) about the controversy evolution vs creationism vs ID and its implications for science education: 96% of the faculty vs. 72% of the students supported the exclusive teaching of evolution while 4% of the faculty vs. 28% of the students favored equal time to evolution, creationism and ID; 92% of the faculty vs. 52% of the students perceived ID as not scientific and proposed to counter evolution or as doctrine consistent with creationism. Although ≈30% of both faculty and students considered religion to be very important in their lives, and ≈20% admitted to praying daily, the faculty was less religious (Religiosity Index faculty = 0.5 and students = 0.75) and, as expected, more knowledgeable about science (Science Index faculty = 2.27 and students = 1.60) and evolution (Evolution Index faculty = 2.48 and students = 1.65) than the students. Because attitudes toward evolution correlate (1) positively with understanding of science/evolution and (2) negatively with religiosity/political ideology, we conclude that science education combined with vigorous public debate should suffice to increase acceptance of naturalistic rationalism and decrease the negative impact of creationism and ID on society’s evolution literacy

    Acceptance of Evolution by America’s Educators of Prospective Teachers

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    Paz-y-Miño-C G & Espinosa A. 2014. Acceptance of Evolution by America’s Educators of Prospective Teachers. New England Science Public: Series Evolution 2(1): 1-92 (ISSN: 2326-0971). In NESP Series Evolution Vol 2 No 1, Paz-y-Miño-C and Espinosa use the conceptual framework of the Incompatibility Hypothesis (i.e. science/evolution and belief in supernatural causation are incompatible) to document the patterns of acceptance of evolution of 495 Educators of Prospective Teachers affiliated with 281 colleges and universities widely distributed in 4 regions, 9 divisions, and 50 states in the United States. These higher-education professionals (65% PhD-, 22% doctorate-holders) were polled in five areas: (i) their views about evolution, creationism and Intelligent Design, (ii) their understanding of how science and the evolutionary process work, (iii) their position about the hypothetical ‘harmony or compatibility’ between science/evolution and supernatural causation, (iv) their awareness of the age of the Earth, its moon, our solar system and the universe, and the application of the concept of evolution to the cosmos, and (v) their personal convictions concerning the evolution and/or creation of humans in the context of the educators’ religiosity. The authors report that acceptance of evolution among these educators was influenced by their level of understanding the foundations of science/evolution and their beliefs in supernatural causation. In comparison to two other populations, whose acceptance of evolution had already been documented in Paz-y-Miño-C’s and Espinosa’s previous research (i.e. New England research faculty, non-educators, and college students; NESP Ser Evol Vol 1 No 1), the educators had an intermediate level of understanding science/evolution, low acceptance of evolution, and high religiosity, as follows: 59% of the educators accepted evolution openly, 51% thought that evolution is definitely true, and 59% admitted to be religious. Among the New England researchers, 94% accepted evolution openly, 82% thought that evolution is definitely true, and 29% admitted to be religious. Among the students, 63% accepted evolution openly, 58% thought that evolution is definitely true, and 37% admitted to be religious. Educators in each of the four regions of the United States (North East, Midwest, South, and West) had science- and evolution-literacy scores below the researchers’ but above the students.’ The educators’ rejection of evolution increased, conspicuously, with increasing level of religiosity. Paz-y-Miño-C and Espinosa indicate that their study is the first to document, comprehensively, the disturbing reality of evolution illiteracy among educators of prospective teachers in the United States. The authors highlight that these professionals are responsible for mentoring the teachers-to-be in the American school system and that their hesitation to embrace evolution resides in a deficient understanding of science/evolution and high religiosity. Paz-y-Miño-C and Espinosa conclude –as in NESP Ser Evol Vol 1 No 1– that harmonious coexistence between science/evolution and religion is illusory. If co-persisting in the future, the relationship between science and religion will fluctuate between moderate and intense antagonism. Note: The complete 92-page study includes 23 figures, statistics, 34 maps, 12 tables, and a companion slide show ‘Image Resources’ for science journalists, researchers and educators (available at Additional Files below). The supplementary materials include 15s figures and 25s tables

    Attitudes toward Evolution at New England Colleges and Universities, United States

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    Paz-y-Miño-C G & Espinosa A. 2013. Attitudes toward Evolution at New England Colleges and Universities, United States. New England Science Public: Series Evolution 1(1): 1-32 (ISSN: 2326-0971). We compile the most significant results of our conceptual and quantitative studies on the patterns of acceptance of evolution at New England colleges and universities, conducted between 2009 and 2012. We examine the views of New England Faculty and Educators of Prospective Teachers (higher-education faculty themselves, specialized in training future teachers) from 35 colleges and universities, as well as a representative sample of College Students from a Public, Private and two Religious institutions who were polled in three areas: the controversy over evolution versus creationism versus Intelligent Design; their understanding of how science and the evolutionary process work; and their personal convictions concerning the evolution and/or creation of humans in the context of their religiosity. We conclude that the controversy over science/evolution and creationism is inherent to the incompatibility between scientific rationalism/empiricism and the belief in supernatural causation, and that long-term harmonious coexistence between science/evolution and creationism –and all its forms— is illusory. Societies will struggle indefinitely with this incompatibility, therefore the interaction between science/evolution and religiosity is destined to fluctuate historically between intense and moderate antagonism

    Dimorphism in quaternary scelidotheriinae (mammalia, xenarthra, phyllophaga)

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    The contributions concerning possible cases of sexual dimorphisms in fossil and living sloths are scarce. Until now, studies in fossil ground sloth sexual dimorphism have been limited to the subfamilies Megatheriinae (Eremotherium) and Mylodontinae (Paramylodon) from the Pliocene and Pleistocene of South America and North America.Scelidotheriinae constitutes an endemic lineage of ground sloths from South American, with a biochron age ranging the lapse ?Friasian?-Lujanian SALMAs (middle Miocene-early Holocene). An integral phylogenetic and taxonomic revision of the Quaternary Scelidotheriinae shows that it is possible to recognize three genera and six species: Scelidotherium Owen (Scelidotherium leptocephalum and S. bravardi), Valgipes Gervais (Valgipes bucklandi), and Catonyx Ameghino (Catonyx cuvieri, C. tarijensis, and C. chiliensis). One of the most noticeable aspects in some specimens analyzed (n= 47) was the presence of two morphtypes in each species at the level of the dorsal crests of the skull (parasagittal crests and sagittal crest) and at the level of the distal-most region of the mandible (only in C. tarijensis). In all but two species (S. leptocephalum and S. bravardi) the two types involve the absence and presence of a sagittal crest. We suggest that specimens with sagittal crest are males, and specimens lacking sagittal crest are females. This represents the third reported ground sloth clade with evidence of sexual dimorphism of the skull and mandible.Fil: Miño Boilini, Ángel Ramón. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Zurita, Alfredo Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentin

    Functional magnetic materials prepared by rapid quenching.

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    165 p.La presente tesis doctoral se fundamenta en la preparación de materiales magnéticos funcionales por el enfriamiento ultrarrápido y en la caracterización de sus propiedades. Los dos primeros capítulos son dedicados a la explicación teórica de la memoria de forma, la súper elasticidad, y la magnetorresistencia gigante. La memoria de forma es un proceso que permite al material deformado regresar a su forma original después del calentamiento térmico

    Functional magnetic materials prepared by rapid quenching.

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    165 p.La presente tesis doctoral se fundamenta en la preparación de materiales magnéticos funcionales por el enfriamiento ultrarrápido y en la caracterización de sus propiedades. Los dos primeros capítulos son dedicados a la explicación teórica de la memoria de forma, la súper elasticidad, y la magnetorresistencia gigante. La memoria de forma es un proceso que permite al material deformado regresar a su forma original después del calentamiento térmico

    Fundamentos del diseno e industrializacion de muebles de linea plana.

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    159 p.Las posibilidades de un país maderero, como lo es Chile, de incrementar sustancialmente sus exportaciones en el rubro muebles, están claramente demostradas en estudios comparativos realizados en otros países exportadores, por ejemplo, Taiwán, país importador de madera, exporta más de 2000 millones de dólares anuales. (INFOR, 2004) A nivel nacional, en los últimos años la industria manufacturera de muebles ha tenido un gran auge de exportaciones; este crecimiento ha generado necesidades inmediatas, entre las cuales se ha podido detectar: Falta de personal capacitado a nivel de trabajadores y profesionales, falta de diseños propios, problemas de calidad, tecnologías atrasadas, etc. (INFOR, 2004) La demanda por muebles continuará aumentando: El país sólo podrá hacer frente a esta demanda en la medida que tenga personal capacitado, una red de productores; pequeños, medianos y grandes, pueda ofrecer diseños, que siendo propios tengan acogida en el mercado internacional, además de un sistema de Calidad para la fabricación de muebles, donde se realicen cabalmente las uniones y se escoja apropiadamente los herrajes de acuerdo al diseño de éstos. La memoria desarrollada pretende en lo fundamental capacitar, transfiriendo al sector productivo, información sobre diseños, sistemas constructivos adecuados para el mercado interno y de exportación y el uso de maquinarias. De acuerdo a lo anterior esta memoria está destinada a la descripción de los principales aspectos del funcionamiento y el uso de maquinaria, sistemas de herrajes y diseño de muebles de línea plana; esto se consiguió adaptando experiencias extranjeras en general, a la realidad nacional, mediante bibliografía obtenida a través de medios digitales, como también por revisiones bibliográficas

    The Jackprot Simulation Couples Mutation Rate with Natural Selection to Illustrate How Protein Evolution Is Not Random

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    Protein evolution is not a random process. Views which attribute randomness to molecular change, deleterious nature to single-gene mutations, insufficient geological time, or population size for molecular improvements to occur, or invoke “design creationism” to account for complexity in molecular structures and biological processes, are unfounded. Scientific evidence suggests that natural selection tinkers with molecular improvements by retaining adaptive peptide sequence. We used slot-machine probabilities and ion channels to show biological directionality on molecular change. Because ion channels reside in the lipid bilayer of cell membranes, their residue location must be in balance with the membrane’s hydrophobic/philic nature; a selective “pore” for ion passage is located within the hydrophobic region. We contrasted the random generation of DNA sequence for KcsA, a bacterial two-transmembrane-domain (2TM) potassium channel, from Streptomyces lividans, with an under-selection scenario, the “jackprot,” which predicted much faster evolution than by chance. We wrote a computer program in JAVA APPLET version 1.0 and designed an online interface, The Jackprot Simulation http://faculty.rwu.edu/cbai/JackprotSimulation.htm, to model a numerical interaction between mutation rate and natural selection during a scenario of polypeptide evolution. Winning the “jackprot,” or highest-fitness complete-peptide sequence, required cumulative smaller “wins” (rewarded by selection) at the first, second, and third positions in each of the 161 KcsA codons (“jackdons” that led to “jackacids” that led to the “jackprot”). The “jackprot” is a didactic tool to demonstrate how mutation rate coupled with natural selection suffices to explain the evolution of specialized proteins, such as the complex six-transmembrane (6TM) domain potassium, sodium, or calcium channels. Ancestral DNA sequences coding for 2TM-like proteins underwent nucleotide “edition” and gene duplications to generate the 6TMs. Ion channels are essential to the physiology of neurons, ganglia, and brains, and were crucial to the evolutionary advent of consciousness. The Jackprot Simulation illustrates in a computer model that evolution is not and cannot be a random process as conceived by design creationists
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