2,110 research outputs found
Міжнародна наукова конференція "Архівознавство як наука"
Проаналізовано внесок істориків і архівістів України в розвиток архівної науки. Вказуються основні розділи архівознавства як науки, що вимагають подальших досліджень.Проанализирован вклад историков и архивистов Украины в развитие архивной науки. Указываются основные разделы архивоведения как науки, которые требуют дальнейших исследований.A contribution of Ukrainian historians and archivists to the archival science development is covered. The basic sections of the archival science which need the further study are indicated
Investigation of MoOx/Al2O3 under Cyclic Operation for Oxidative and Non-Oxidative Dehydrogenation of Propane
A MoOx/Al2O3 catalyst was synthesised and tested for oxidative (ODP) and non-oxidative (DP) dehydrogenation of propane in a reaction cycle of ODP followed by DP and a second ODP run. Characterisation results show that the fresh catalyst contains highly dispersed Mo oxide species in the +6 oxidation state with tetrahedral coordination as [MoVIO4]2− moieties. In situ X-ray Absorption Spectroscopy (XAS) shows that [MoVIO4]2− is present during the first ODP run of the reaction cycle and is reduced to MoIVO2 in the following DP run. The reduced species are partly re-oxidised in the subsequent second ODP run of the reaction cycle. The partly re-oxidised species exhibit oxidation and coordination states that are lower than 6 but higher than 4 and are referred to as MoxOy. These species significantly improved propene formation (relatively 27% higher) in the second ODP run at similar propane conversion activity. Accordingly, the initial tetrahedral [MoVIO4]2− present during the first ODP run of the reaction cycle is active for propane conversion; however, it is unselective for propene. The reduced MoIVO2 species are relatively less active and selective for DP. It is suggested that the MoxOy species generated by the reaction cycle are active and selective for ODP. The vibrational spectroscopic data indicate that the retained surface species are amorphous carbon deposits with a higher proportion of aromatic/olefinic like species
Application of Inelastic Neutron Scattering to the Methanol-to-Gasoline Reaction Over a ZSM-5 Catalyst
Inelastic neutron scattering (INS) is used to investigate a ZSM-5 catalyst that has been exposed to methanol vapour at elevated temperature. In-line mass spectrometric analysis of the catalyst exit stream confirms methanol-to-gasoline chemistry, whilst ex situ INS measurements detect hydrocarbon species formed in/on the catalyst during methanol conversion. These preliminary studies demonstrate the capability of INS to complement infrared spectroscopic characterisation of the hydrocarbon pool present in/on ZSM-5 during the MTG reaction
Quantum delocalization of molecular hydrogen in alkali-graphite intercalates
The adsorption of molecular hydrogen (H-2) in the graphite intercalation compound KC24 is studied both experimentally and theoretically. High-resolution inelastic neutron data show spectral features consistent with a strong pinning of H-2 along a single axis. First-principles calculations provide novel insight into the nature of H-2 binding in intercalates but fail to account for the symmetry of the H-2 orientational potential deduced from experiment. The above discrepancy disappears once the H-2 center of mass is allowed to delocalize in the quantum-mechanical sense across three vicinal adsorption sites, naturally leading to the well-known saturation coverage of similar to 2H(2) per metal atom in this material. Our results demonstrate that H-2 storage in metal-doped carbon substrates can be severely affected by hitherto unexplored quantum-mechanical effects
The effects of supernovae on the dynamical evolution of binary stars and star clusters
In this chapter I review the effects of supernovae explosions on the
dynamical evolution of (1) binary stars and (2) star clusters.
(1) Supernovae in binaries can drastically alter the orbit of the system,
sometimes disrupting it entirely, and are thought to be partially responsible
for `runaway' massive stars - stars in the Galaxy with large peculiar
velocities. The ejection of the lower-mass secondary component of a binary
occurs often in the event of the more massive primary star exploding as a
supernova. The orbital properties of binaries that contain massive stars mean
that the observed velocities of runaway stars (10s - 100s km s) are
consistent with this scenario.
(2) Star formation is an inherently inefficient process, and much of the
potential in young star clusters remains in the form of gas. Supernovae can in
principle expel this gas, which would drastically alter the dynamics of the
cluster by unbinding the stars from the potential. However, recent numerical
simulations, and observational evidence that gas-free clusters are observed to
be bound, suggest that the effects of supernova explosions on the dynamics of
star clusters are likely to be minimal.Comment: 16 pages, to appear in the 'Handbook of Supernovae', eds. Paul Murdin
and Athem Alsabti. This version replaces an earlier version that contained
several typo
Eles, os juízes
O exercício democrático da atividade jurisdicional impõe a motivação das decisões emanadas do Poder Judiciário, uma das faces do poder estatal. Assim, a fundamental necessidade de motivação dos atos judiciais decisórios, como a sentença, contribuiu para a elevação dessa garantia à categoria de princípio constitucional fundamental, incidente sobre o âmbito do processo civil e com repercussões sobre todo o plano do sistema jurídico. Contudo, igualmente necessária é a extração dos significantes a respeito do referido imperativo, assim como o estabelecimento de critérios para a adequada e racional fundamentação das decisões judiciais. Nesse sentido, deve a fundamentação observar os requisitos da racionalidade, coerência e razoabilidade. À admissão de tais condicionantes acrescenta-se breve análise sobre o respeito aos precedentes como forma de conferir legitimidade à decisão, bem como de realizar a segurança jurídica, a previsibilidade e a igualdade na aplicação do direito, ideais fundamentais ao Estado democrático de direito
Robot life: simulation and participation in the study of evolution and social behavior.
This paper explores the case of using robots to simulate evolution, in particular the case of Hamilton's Law. The uses of robots raises several questions that this paper seeks to address. The first concerns the role of the robots in biological research: do they simulate something (life, evolution, sociality) or do they participate in something? The second question concerns the physicality of the robots: what difference does embodiment make to the role of the robot in these experiments. Thirdly, how do life, embodiment and social behavior relate in contemporary biology and why is it possible for robots to illuminate this relation? These questions are provoked by a strange similarity that has not been noted before: between the problem of simulation in philosophy of science, and Deleuze's reading of Plato on the relationship of ideas, copies and simulacra
Inference of population splits and mixtures from genome-wide allele frequency data
Many aspects of the historical relationships between populations in a species
are reflected in genetic data. Inferring these relationships from genetic data,
however, remains a challenging task. In this paper, we present a statistical
model for inferring the patterns of population splits and mixtures in multiple
populations. In this model, the sampled populations in a species are related to
their common ancestor through a graph of ancestral populations. Using
genome-wide allele frequency data and a Gaussian approximation to genetic
drift, we infer the structure of this graph. We applied this method to a set of
55 human populations and a set of 82 dog breeds and wild canids. In both
species, we show that a simple bifurcating tree does not fully describe the
data; in contrast, we infer many migration events. While some of the migration
events that we find have been detected previously, many have not. For example,
in the human data we infer that Cambodians trace approximately 16% of their
ancestry to a population ancestral to other extant East Asian populations. In
the dog data, we infer that both the boxer and basenji trace a considerable
fraction of their ancestry (9% and 25%, respectively) to wolves subsequent to
domestication, and that East Asian toy breeds (the Shih Tzu and the Pekingese)
result from admixture between modern toy breeds and "ancient" Asian breeds.
Software implementing the model described here, called TreeMix, is available at
http://treemix.googlecode.comComment: 28 pages, 6 figures in main text. Attached supplement is 22 pages, 15
figures. This is an updated version of the preprint available at
http://precedings.nature.com/documents/6956/version/
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