946 resultados para Humanist and Scientist


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A second English translation of Alexander von Humboldt's account of travel to South America, the Relation historique (1814–25), was published between 1852 and 1853. Appearing some 30 years after the first seven-volume translation (1814–29) by Helen Maria Williams, this second rendering of the Personal Narrative by Thomasina Ross was an abridged version that aimed to make Humboldt's travelogue more relevant to the mid-century reader. This translation has largely been overlooked by Humboldt scholars, despite it being a far more affordable, accessible and popular edition. I discuss here how Ross's revisions can be understood within a larger process of rereading and revision that responded to critics’ assessments of the first translation. Emphasising the status of the Personal Narrative as a text in flux, I assess how Ross modernised it to meet the demands of a new readership, recasting the image that Humboldt had constructed of himself as a travelling scientist, scientific writer and member of the international scientific community.

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This article examines how conventional studio production strategies were active in the construction of political meaning in the 1974 television play 'Absolute Beginners' written by Trevor Griffiths. Produced for the BBC anthology series Fall of Eagles, the play dramatises Lenin's involvement with the Russian Social Democratic Workers Party (RSDWP) and explores the contradictions between personal ethics and political necessity. Through close textual analysis and contextual discussion of other plays in the series, this piece demonstrates how shot patterns and spatial and performative devices in 'Absolute Beginners' supported the drama's socialist-humanist themes. Drawing on existing writing about the studio mode, it argues that the qualities of intimacy and presentational distance that it engendered were highly appropriate for the personal and the political dialectic in 'Absolute Beginners'. While using authorship as a convenient category for referring to the coherence of Griffiths' thematic concerns and dramatic structure during this period, the article complicates notions of the television dramatist as author by arguing for the importance of visual style and showing how 'ordinary' studio form was operational in the play's political meanings.

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Discussions of popular sovereignty in early modern England have usually been premised upon a sharp distinction between ‘legal/constitutional’ forms of discourse (which merely interpret the law) and ‘political’ ones (which focus upon the right to make it). In such readings of the period, Henry Parker has a pivotal position as a writer who abandoned merely legalistic thinking. This chapter takes a different view. It argues that Parker’s major intellectual achievement was not so much to abandon legal/constitutional discourse as to offer a theorisation of its most distinctive features: he offered an account of a new kind of politics in which concern for ‘interests’ in property and in self-preservation replaced humanist concern with promotion of virtue. Parker drew upon ideas about representation best expressed by Sir Thomas Smith and ideas about law best expressed by Oliver St John. The theory he developed was not intended as a justification of legislative sovereignty, but of adjudicative supremacy. His picture of the two Houses as supreme adjudicators was meant to block the path to direct democracy. But the adjudicative standpoint they came to occupy presupposed that freeborn adults had ‘interests’ in life, liberty, and possessions. This had democratising implications.

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The db/db mice serve as a good model for type 2 diabetes characterized by hyperinsulinaemia and progressive hyperglycaemia. There are limited and conflicting data on the cardiovascular changes in this model. The aim of the present study was to characterize the cardiovascular and autonomic phenotype of male db/db mice and evaluate the role of angiotensin II AT(1) receptors. Radiotelemetry was used to monitor 24 h blood pressure (BP) in mice for 8 weeks. Parameters measured were mean arterial pressure (MAP), heart rate (HR) and their variabilities. In 8-week-old db/db mice, the MAP and BP circadian rhythms were not different from age-matched control mice, while HR and locomotor activity were decreased. With ageing, MAP gradually increased in db/db mice, and the 12 h light values did not dip significantly from the 12 h dark periods. In 14-week-old mice, MAP was increased during light (101 +/- 1 versus 117 +/- 2 mmHg, P < 0.01; control versus db/db mice) and dark phases (110 +/- 1.7 versus 121 +/- 3.1 mmHg, P < 0.01; control versus db/db mice). This increase in MAP was associated with a significant increase in plasma angiotensin-converting enzyme activity and angiotensin II levels. Chronic treatment with losartan (10 mg kg(-1) day(-1)) blocked the increase in MAP in db/db mice, with no effect in control animals. Spectral analysis was used to monitor autonomic cardiovascular function. The circadian rhythm observed in systolic arterial pressure variance and its low-frequency component in control mice was absent in db/db mice. There were no changes in HR variability and spontaneous baroreflex sensitivity between control and db/db mice. The results document an age-related increase in MAP in db/db mice, which can be reduced by antagonism of angiotensin II AT(1) receptors, and alterations in autonomic balance and components of the renin-angiotensin system.

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Although there is accumulated evidence of a role for Notch in the developing lung, it is still unclear how disruption of Notch signaling affects lung progenitor cell fate and differentiation events in the airway epithelium. To address this issue, we inactivated Notch signaling conditionally in the endoderm using a Shh-Cre deleter mouse line and mice carrying floxed alleles of the Pofut1 gene, which encodes an O-fucosyltransferase essential for Notch-ligand binding. We also took the same conditional approach to inactivate expression of Rbpjk, which encodes the transcriptional effector of canonical Notch signaling. Strikingly, these mutants showed an almost identical lung phenotype characterized by an absence of secretory Clara cells without evidence of cell death, and showed airways populated essentially by ciliated cells, with an increase in neuroendocrine cells. This phenotype could be further replicated in cultured wild-type lungs by disrupting Notch signaling with a gamma-secretase inhibitor. Our data suggest that Notch acts when commitment to a ciliated or non-ciliated cell fate occurs in proximal progenitors, silencing the ciliated program in the cells that will continue to expand and differentiate into secretory cells. This mechanism may be crucial to define the balance of differentiated cell profiles in different generations of the developing airways. It might also be relevant to mediate the metaplastic changes in the respiratory epithelium that occur in pathological conditions, such as asthma and chronic obstructive pulmonary disease.

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Very large scale computations are now becoming routinely used as a methodology to undertake scientific research. In this context, `provenance systems' are regarded as the equivalent of the scientist's logbook for in silico experimentation: provenance captures the documentation of the process that led to some result. Using a protein compressibility analysis application, we derive a set of generic use cases for a provenance system. In order to support these, we address the following fundamental questions: what is provenance? how to record it? what is the performance impact for grid execution? what is the performance of reasoning? In doing so, we define a technologyindependent notion of provenance that captures interactions between components, internal component information and grouping of interactions, so as to allow us to analyse and reason about the execution of scientific processes. In order to support persistent provenance in heterogeneous applications, we introduce a separate provenance store, in which provenance documentation can be stored, archived and queried independently of the technology used to run the application. Through a series of practical tests, we evaluate the performance impact of such a provenance system. In summary, we demonstrate that provenance recording overhead of our prototype system remains under 10% of execution time, and we show that the recorded information successfully supports our use cases in a performant manner.

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Scientific workflows are becoming a valuable tool for scientists to capture and automate e-Science procedures. Their success brings the opportunity to publish, share, reuse and repurpose this explicitly captured knowledge. Within the myGrid project, we have identified key resources that can be shared including complete workflows, fragments of workflows and constituent services. We have examined the alternative ways these can be described by their authors (and subsequent users), and developed a unified descriptive model to support their later discovery. By basing this model on existing standards, we have been able to extend existing Web Service and Semantic Web Service infrastructure whilst still supporting the specific needs of the e-Scientist. myGrid components enable a workflow life-cycle that extends beyond execution, to include discovery of previous relevant designs, reuse of those designs, and subsequent publication. Experience with example groups of scientists indicates that this cycle is valuable. The growing number of workflows and services mean more work is needed to support the user in effective ranking of search results, and to support the repurposing process.

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The number of citations of a scientific publication or of an individual scientist has become an important factor of quality assessment in science. We report a study of the statistical distribution of the citation index of both scientific publications and scientists. We give numerical evidence that Tsallis (power law) statistics explains the entire distribution over eight orders of magnitude (10-4 to 10(4)). Also, we draw Zipf plots in order to analyze the statistical distribution of the citation index of Brazilian and international physicists and chemists. The relatively small group of Brazilian scientists seems more adequate to explain the dynamics of the citation index. In this case, we find that the distribution of the citation index can also be explained by a gradually truncated power law with similar parameters. We finally discuss possible mechanisms behind the citation index of scientists and scientific publications.

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In 1956 African honeybee queens (Apis mellifera scutellata) were imported from South Africa and Tanzania to Brazil, as part of a government project to increase Brazilian honey production. The European honeybees existing in that country had not adapted well to the tropical conditions and consequently, had a low productivity. The newly introduced bee was known to produce substantially more honey than the other subspecies, but was also famous for its great aggressiveness and quicker attack of intruders with less disturbance. Hoping to create a new hybrid bee that would be both docile and productive, the scientist Warwick Estevam Kerr tried to cross the African and the European subspecies under controlled conditions. However, an accident resulted in the escape of 26 swarms into the Brazilian countryside, where their queens mated with drones of the European resident honeybees. The poly-hybrid bees resulting from these crossings expressed scutellata-like reproductive, foraging, and defensive behaviors and, for this reason, were called Africanized honeybees. They spread rapidly from the introduction area of the African honeybees (near Rio Claro, São Paulo state) to as far south as mid-Argentina and to the north of Texas, also settling in Arizona, New Mexico, California and Nevada, due to their high adaptability to variable ecological conditions. In spite of a few undesirable behaviors, these bees have been invoking larger economic interest because they produce much more honey, have good resistance to diseases and are excellent pollinators. In Brazil, because people frequently disturb the environment, the occupation of urban refuges by Africanized honeybees has been increasing in the last years. The concern with accidents is generally associated with the high swarming frequency recorded during the year and the variety of shelters available in urban areas. This paper deals with the biological characteristics of the Africanized honeybees, their nesting behavior in urban environments, and accidents caused by these bees in Brazilian cities.

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Carbon nanoscrolls (graphene layers rolled up into papyrus-like tubular structures) are nanostructures with unique and interesting characteristics that could be exploited to build several new nanodevices. However, an efficient and controlled synthesis of these structures was not achieved yet, making its large scale production a challenge to materials scientists. Also, the formation process and detailed mechanisms that occur during its synthesis are not completely known. In this work, using fully atomistic molecular dynamics simulations, we discuss a possible route to nanoscrolls made from graphene layers deposited over silicon oxide substrates containing chambers/pits. The scrolling mechanism is triggered by carbon nanotubes deposited on the layers. The process is completely general and can be used to produce scrolls from other lamellar materials, like boron nitride, for instance. © 2013 American Institute of Physics.

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Festuccia WT, Blanchard PG, Oliveira TB, Magdalon J, Paschoal VA, Richard D, Deshaies Y. PPAR gamma activation attenuates cold-induced upregulation of thyroid status and brown adipose tissue PGC-1 alpha and D2. Am J Physiol Regul Integr Comp Physiol 303: R1277-R1285, 2012. First published October 24, 2012; doi:10.1152/ajpregu.00299.2012.-Here, we investigated whether pharmacological PPAR gamma activation modulates key early events in brown adipose tissue (BAT) recruitment induced by acute cold exposure with the aim of unraveling the interrelationships between sympathetic and PPAR gamma signaling. Sprague-Dawley rats treated or not with the PPAR gamma ligand rosiglitazone (15 mg.kg(-1).day(-1), 7 days) were kept at 23 degrees C or exposed to cold (5 degrees C) for 24 h and evaluated for BAT gene expression, sympathetic activity, thyroid status, and adrenergic signaling. Rosiglitazone did not affect the reduction in body weight gain and the increase in feed efficiency, VO2, and BAT sympathetic activity induced by 24-h cold exposure. Rosiglitazone strongly attenuated the increase in serum total and free T4 and T3 levels and BAT iodothyronine deiodinase type 2 (D2) and PGC-1 alpha mRNA levels and potentiated the reduction in BAT thyroid hormone receptor (THR) beta mRNA levels induced by cold. Administration of T3 to rosiglitazone-treated rats exacerbated the cold-induced increase in energy expenditure but did not restore a proper activation of D2 and PGC-1 alpha, nor further increased uncoupling protein 1 expression. Regarding adrenergic signaling, rosiglitazone did not affect the changes in BAT cAMP content and PKA activity induced by cold. Rosiglitazone alone or in combination with cold increased CREB binding to DNA, but it markedly reduced the expression of one of its major coactivators, CREB binding protein. In conclusion, pharmacological PPAR gamma activation impairs short-term cold elicitation of BAT adrenergic and thyroid signaling, which may result in abnormal tissue recruitment and thermogenic activity.

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We analyse the dependence of the luminosity function (LF) of galaxies in groups on group dynamical state. We use the Gaussianity of the velocity distribution of galaxy members as a measurement of the dynamical equilibrium of groups identified in the Sloan Digital Sky Survey Data Release 7 by Zandivarez & Martinez. We apply the Anderson-Darling goodness-of-fit test to distinguish between groups according to whether they have Gaussian or non-Gaussian velocity distributions, i.e. whether they are relaxed or not. For these two subsamples, we compute the (0.1)r-band LF as a function of group virial mass and group total luminosity. For massive groups, , we find statistically significant differences between the LF of the two subsamples: the LFs of groups that have Gaussian velocity distributions have a brighter characteristic absolute magnitude (similar to 0.3 mag) and a steeper faint-end slope (similar to 0.25). We detect a similar effect when comparing the LF of bright [M-0.1r(group) - 5log(h) < -23.5] Gaussian and non-Gaussian groups. Our results indicate that, for massive/luminous groups, the dynamical state of the system is directly related to the luminosity of its galaxy members.

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Congenital heart disease (CHD) occurs in similar to 1% of newborns. CHD arises from many distinct etiologies, ranging from genetic or genomic variation to exposure to teratogens, which elicit diverse cell and molecular responses during cardiac development. To systematically explore the relationships between CHD risk factors and responses, we compiled and integrated comprehensive datasets from studies of CHD in humans and model organisms. We examined two alternative models of potential functional relationships between genes in these datasets: direct convergence, in which CHD risk factors significantly and directly impact the same genes and molecules and functional convergence, in which risk factors significantly impact different molecules that participate in a discrete heart development network. We observed no evidence for direct convergence. In contrast, we show that CHD risk factors functionally converge in protein networks driving the development of specific anatomical structures (e.g., outflow tract, ventricular septum, and atrial septum) that are malformed by CHD. This integrative analysis of CHD risk factors and responses suggests a complex pattern of functional interactions between genomic variation and environmental exposures that modulate critical biological systems during heart development.

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The relation between the intercepted light and orchard productivity was considered linear, although this dependence seems to be more subordinate to planting system rather than light intensity. At whole plant level not always the increase of irradiance determines productivity improvement. One of the reasons can be the plant intrinsic un-efficiency in using energy. Generally in full light only the 5 – 10% of the total incoming energy is allocated to net photosynthesis. Therefore preserving or improving this efficiency becomes pivotal for scientist and fruit growers. Even tough a conspicuous energy amount is reflected or transmitted, plants can not avoid to absorb photons in excess. The chlorophyll over-excitation promotes the reactive species production increasing the photoinhibition risks. The dangerous consequences of photoinhibition forced plants to evolve a complex and multilevel machine able to dissipate the energy excess quenching heat (Non Photochemical Quenching), moving electrons (water-water cycle , cyclic transport around PSI, glutathione-ascorbate cycle and photorespiration) and scavenging the generated reactive species. The price plants must pay for this equipment is the use of CO2 and reducing power with a consequent decrease of the photosynthetic efficiency, both because some photons are not used for carboxylation and an effective CO2 and reducing power loss occurs. Net photosynthesis increases with light until the saturation point, additional PPFD doesn’t improve carboxylation but it rises the efficiency of the alternative pathways in energy dissipation but also ROS production and photoinhibition risks. The wide photo-protective apparatus, although is not able to cope with the excessive incoming energy, therefore photodamage occurs. Each event increasing the photon pressure and/or decreasing the efficiency of the described photo-protective mechanisms (i.e. thermal stress, water and nutritional deficiency) can emphasize the photoinhibition. Likely in nature a small amount of not damaged photosystems is found because of the effective, efficient and energy consuming recovery system. Since the damaged PSII is quickly repaired with energy expense, it would be interesting to investigate how much PSII recovery costs to plant productivity. This PhD. dissertation purposes to improve the knowledge about the several strategies accomplished for managing the incoming energy and the light excess implication on photo-damage in peach. The thesis is organized in three scientific units. In the first section a new rapid, non-intrusive, whole tissue and universal technique for functional PSII determination was implemented and validated on different kinds of plants as C3 and C4 species, woody and herbaceous plants, wild type and Chlorophyll b-less mutant and monocot and dicot plants. In the second unit, using a “singular” experimental orchard named “Asymmetric orchard”, the relation between light environment and photosynthetic performance, water use and photoinhibition was investigated in peach at whole plant level, furthermore the effect of photon pressure variation on energy management was considered on single leaf. In the third section the quenching analysis method suggested by Kornyeyev and Hendrickson (2007) was validate on peach. Afterwards it was applied in the field where the influence of moderate light and water reduction on peach photosynthetic performances, water requirements, energy management and photoinhibition was studied. Using solar energy as fuel for life plant is intrinsically suicidal since the high constant photodamage risk. This dissertation would try to highlight the complex relation existing between plant, in particular peach, and light analysing the principal strategies plants developed to manage the incoming light for deriving the maximal benefits as possible minimizing the risks. In the first instance the new method proposed for functional PSII determination based on P700 redox kinetics seems to be a valid, non intrusive, universal and field-applicable technique, even because it is able to measure in deep the whole leaf tissue rather than the first leaf layers as fluorescence. Fluorescence Fv/Fm parameter gives a good estimate of functional PSII but only when data obtained by ad-axial and ab-axial leaf surface are averaged. In addition to this method the energy quenching analysis proposed by Kornyeyev and Hendrickson (2007), combined with the photosynthesis model proposed by von Caemmerer (2000) is a forceful tool to analyse and study, even in the field, the relation between plant and environmental factors such as water, temperature but first of all light. “Asymmetric” training system is a good way to study light energy, photosynthetic performance and water use relations in the field. At whole plant level net carboxylation increases with PPFD reaching a saturating point. Light excess rather than improve photosynthesis may emphasize water and thermal stress leading to stomatal limitation. Furthermore too much light does not promote net carboxylation improvement but PSII damage, in fact in the most light exposed plants about 50-60% of the total PSII is inactivated. At single leaf level, net carboxylation increases till saturation point (1000 – 1200 μmolm-2s-1) and light excess is dissipated by non photochemical quenching and non net carboxylative transports. The latter follows a quite similar pattern of Pn/PPFD curve reaching the saturation point at almost the same photon flux density. At middle-low irradiance NPQ seems to be lumen pH limited because the incoming photon pressure is not enough to generate the optimum lumen pH for violaxanthin de-epoxidase (VDE) full activation. Peach leaves try to cope with the light excess increasing the non net carboxylative transports. While PPFD rises the xanthophyll cycle is more and more activated and the rate of non net carboxylative transports is reduced. Some of these alternative transports, such as the water-water cycle, the cyclic transport around the PSI and the glutathione-ascorbate cycle are able to generate additional H+ in lumen in order to support the VDE activation when light can be limiting. Moreover the alternative transports seems to be involved as an important dissipative way when high temperature and sub-optimal conductance emphasize the photoinhibition risks. In peach, a moderate water and light reduction does not determine net carboxylation decrease but, diminishing the incoming light and the environmental evapo-transpiration request, stomatal conductance decreases, improving water use efficiency. Therefore lowering light intensity till not limiting levels, water could be saved not compromising net photosynthesis. The quenching analysis is able to partition absorbed energy in the several utilization, photoprotection and photo-oxidation pathways. When recovery is permitted only few PSII remained un-repaired, although more net PSII damage is recorded in plants placed in full light. Even in this experiment, in over saturating light the main dissipation pathway is the non photochemical quenching; at middle-low irradiance it seems to be pH limited and other transports, such as photorespiration and alternative transports, are used to support photoprotection and to contribute for creating the optimal trans-thylakoidal ΔpH for violaxanthin de-epoxidase. These alternative pathways become the main quenching mechanisms at very low light environment. Another aspect pointed out by this study is the role of NPQ as dissipative pathway when conductance becomes severely limiting. The evidence that in nature a small amount of damaged PSII is seen indicates the presence of an effective and efficient recovery mechanism that masks the real photodamage occurring during the day. At single leaf level, when repair is not allowed leaves in full light are two fold more photoinhibited than the shaded ones. Therefore light in excess of the photosynthetic optima does not promote net carboxylation but increases water loss and PSII damage. The more is photoinhibition the more must be the photosystems to be repaired and consequently the energy and dry matter to allocate in this essential activity. Since above the saturation point net photosynthesis is constant while photoinhibition increases it would be interesting to investigate how photodamage costs in terms of tree productivity. An other aspect of pivotal importance to be further widened is the combined influence of light and other environmental parameters, like water status, temperature and nutrition on peach light, water and phtosyntate management.

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Our generation of computational scientists is living in an exciting time: not only do we get to pioneer important algorithms and computations, we also get to set standards on how computational research should be conducted and published. From Euclid’s reasoning and Galileo’s experiments, it took hundreds of years for the theoretical and experimental branches of science to develop standards for publication and peer review. Computational science, rightly regarded as the third branch, can walk the same road much faster. The success and credibility of science are anchored in the willingness of scientists to expose their ideas and results to independent testing and replication by other scientists. This requires the complete and open exchange of data, procedures and materials. The idea of a “replication by other scientists” in reference to computations is more commonly known as “reproducible research”. In this context the journal “EAI Endorsed Transactions on Performance & Modeling, Simulation, Experimentation and Complex Systems” had the exciting and original idea to make the scientist able to submit simultaneously the article and the computation materials (software, data, etc..) which has been used to produce the contents of the article. The goal of this procedure is to allow the scientific community to verify the content of the paper, reproducing it in the platform independently from the OS chosen, confirm or invalidate it and especially allow its reuse to reproduce new results. This procedure is therefore not helpful if there is no minimum methodological support. In fact, the raw data sets and the software are difficult to exploit without the logic that guided their use or their production. This led us to think that in addition to the data sets and the software, an additional element must be provided: the workflow that relies all of them.