523 research outputs found
XML documents schema design
The eXtensible Markup Language (XML) is fast emerging as the dominant standard for storing, describing and interchanging data among various systems and databases on the intemet. It offers schema such as Document Type Definition (DTD) or XML Schema Definition (XSD) for defining the syntax and structure of XML documents. To enable efficient usage of XML documents in any application in large scale electronic environment, it is necessary to avoid data redundancies and update anomalies. Redundancy and anomalies in XML documents can lead not only to higher data storage cost but also to increased costs for data transfer and data manipulation.To overcome this problem, this thesis proposes to establish a formal framework of XML document schema design. To achieve this aim, we propose a method to improve and simplify XML schema design by incorporating a conceptual model of the DTD with a theory of database normalization. A conceptual diagram, Graph-Document Type Definition (G-DTD) is proposed to describe the structure of XML documents at the schema level. For G- DTD itself, we define a structure which incorporates attributes, simple elements, complex elements, and relationship types among them. Furthermore, semantic constraints are also precisely defined in order to capture semantic meanings among the defined XML objects.In addition, to provide a guideline to a well-designed schema for XML documents, we propose a set of normal forms for G-DTD on the basis of rules proposed by Arenas and Libkin and Lv. et al. The corresponding normalization rules to transform from a G- DTD into a normal form schema are also discussed. A case study is given to illustrate the applicability of the concept. As a result, we found that the new normal forms are more concise and practical, in particular as they allow the user to find an 'optimal' structure of XML elements/attributes at the schema level. To prove that our approach is applicable for the database designer, we develop a prototype of XML document schema design using a Z formal specification language. Finally, using the same case study, this formal specification is tested to check for correctness and consistency of the specification. Thus, this gives a confidence that our prototype can be implemented successfully to generate an automatic XML schema design
Interpreting a Finitary Pi-Calculus in Differential Interaction Nets
15 pagesInternational audienceWe propose and study a translation of a pi-calculus without sums nor replication/recursion into an untyped and essentially promotion-free version of differential interaction nets. We define a transition system of labeled processes and a transition system of labeled differential interaction nets. We prove that our translation from processes to nets is a bisimulation between these two transition systems. This shows that differential interaction nets are sufficiently expressive for representing concurrency and mobility, as formalized by the pi-calculus
Order and Disorder in TypeâII InAs/InAsSb Superlattices
We employ crossâsectional scanning tunneling microscopy (STM) to examine
how an asâgrown InAs/InAsSb superlattice differs from the intended one as regards
translational invariance in (001) planes perpendicular to the growth direction. This
requires atomicâresolution, lateral surveys paralleling the buffer/epilayer interface for up
to a micron in orthogonal (â1â10) or (1â10) cross sections, together with repeated lateral
surveys at representative vertical locations (i.e., spanned superlattice repeats) within the
multilayer stack.
We show that STM may be used to accurately map the period fluctuations
throughout this superlattice. The concept, analogous to Bragg's law in highâresolution
xâray diffraction, relies on an analysis of the [001]âconvolved reciprocalâspace satellite
peaks obtained from discrete Fourier transforms of individual STM images. Properly
implemented, the technique enables local period measurements that reliably discriminate
lateral fluctuations localized to within ~ 40 nm along directions in the growth
plane. While not as accurate as xâray, the inherent, singleâimage measurement error
associated with the method may be made as small as 0.1%, allowing the lateral period
fluctuations contributing to inhomogeneous energy broadening and carrier localization in
these structures to be pinpointed and quantified. The direct visualization of
unexpectedlyâlarge fluctuations on nanometer length scales is tied to a stochastic
description of correlated interface roughness.
We also introduce a new technique to automatically tabulate the crystalline
coordinates of previouslyâidentified topâlayer antimony atoms and construct the
antimony pairâcorrelation functions for orthogonal cross sections. Nearestâneighbor
correlations on opposing cleavage faces are inversely related, with the (â1â10) deficit at
nearestâneighbor sites balanced by a compensating (1â10) surplus. The logarithm of this
preference scales inversely with bulk antimony fraction. In more vivid physical terms,
the preferential [110]âincorporation of nearestâneighbor antimony atoms in the bulk is
traced to the inferred concentration of [110]âoriented antimony dimers at the growth
surfac
Network Meta-Analysis of Chicken Microarray Data following Avian Influenza Challenge-A Comparison of Highly and Lowly Pathogenic Strains
The current bioinformatics study was undertaken to analyze the transcriptome of chicken (Gallus gallus) after influenza A virus challenge. A meta-analysis was carried out to explore the host expression response after challenge with lowly pathogenic avian influenza (LPAI) (H1N1, H2N3, H5N2, H5N3 and H9N2) and with highly pathogenic avian influenza (HPAI) H5N1 strains. To do so, ten microarray datasets obtained from the Gene Expression Omnibus (GEO) database were normalized and meta-analyzed for the LPAI and HPAI host response individually. Different undirected networks were constructed and their metrics determined e.g., degree centrality, closeness centrality, harmonic centrality, subgraph centrality and eigenvector centrality. The results showed that, based on criteria of centrality, the CMTR1, EPSTI1, RNF213, HERC4L, IFIT5 and LY96 genes were the most significant during HPAI challenge, with PARD6G, HMG20A, PEX14, RNF151 and TLK1L having the lowest values. However, for LPAI challenge, ZDHHC9, IMMP2L, COX7C, RBM18, DCTN3, and NDUFB1 genes had the largest values for aforementioned criteria, with GTF3C5, DROSHA, ATRX, RFWD2, MED23 and SEC23B genes having the lowest values. The results of this study can be used as a basis for future development of treatments/preventions of the effects of avian influenza in chicken
Geochemical Aspects of Fluid/rock Interaction in Hydrothermal Kaolinization at the Hiraki Mine, Hyogo Prefecture, Japan
A kaolin deposit at the Hiraki mine, situated approximately 50 km northwest of Osaka, SW Japan, occurs in the rhyolitic non-welded tuff sandwiched between underlying rhyolite and overlying rhyolitic welded tuff of Late Cretaceous. Volcanostratigraphy of the mine area is designated as follows: (in ascending order) the rhyolite, the non-welded tuff (with three members) and the Hiraki rhyolitic vitritic welded tuff. The boundary between the rhyolite and the non-welded tuff is transitional, whereas that between the non-welded tuff and the Hiraki welded tuff is defined as unconformity. Chemically, these volcanic and pyroclastic rocks are all of low alkali and peraluminous. Variation diagrams for incompatible element pairs, both major and trace elements, suggest that the deposit was altered from a single precursor, the rhyolitic non-welded tuff. The deposit was formed by the interaction between the rhyolitic non-welded tuff and acidic fluids which passed mainly through the fracture zones formed after the emplacement of the overlying welded tuff. Mineralogically, it is composed exclusively of kaolin group with a few chlorite, illite, montmorillonite, mixed-layer clay minerals, sericite and pyrophyllite, confined to fracture zones, and ubiquitous occurrence of quartz throughout the deposit in varying degrees of abundance. Essentially, it is a kaolinite monomineralic deposit, showing no distinct zonal distribution of alteration mineral assemblages.
K-Ar ages were measured on the whole-rock samples of felsic volcanics and the clays from the Hiraki mine. The results are: (1) 70.0 ± 1.5 Ma for the underlying Kamogawa rhyolite; (2) 68.9 ± 1.6 Ma and 69.1 ± 1.6 Ma for the least-altered and altered rhyolitic non-welded tuff (= ore horizon), respectively; (3) 67.6 ± 1.5 Ma for the unconformably overlying rhyolitic Hiraki welded tuff; and (4) 63.8 ± 1.5 Ma for clays from the fracture zone crosscutting the whole volcanic sequence. These ages are fairly consistent with the volcanostratigraphy in the mine area, indicating that various volcanisms and mineralization took place within a time span of a few million years in the latest Cretaceous to the earliest Tertiary Periods. The unconformity recognized, therefore, means a minor time-gap, not a long cessation of volcanism, at least in the Hiraki mine area.
Immobility of element during the hydrothermal alteration was tested for Al2O3, TiO2, Nb and Zr. Among them Zr and Nb show highest immobility throughout the deposit. Mass-transfer calculation, based on Zr as an immobile element monitor, and petrographic evidences reveal the followings: (1) dissolution of CaO, Na2O, K2O, Fe2O3 and MnO in the kaolinite zone; (2) slight enrichment of K2O and Fe2O3 in the sericite "zone"** and chlorite "zone", respectively; (3) dissolution of silica at the initial stage and later precipitated as quartz from the fluid introduced to the system during alteration process; (4) immobility of Zr and Nb, as well as less immobility of TiO2 and Al2O3 in the whole deposit; and (5) Al2O3 content in the non-welded tuff might vary within the range of 15 to 24 wt% .
Hydrogen and oxygen isotopic studies were carried out on the ore specimens and whole-rock samples to obtain information on the type of water responsible for alteration process and nature of water-rock interaction at the Hiraki mine. ÎŽD and ÎŽ18O analyses, expressed as â° relative to SMOW, of the volcanic host rocks and ores (kaolinite+quartz) reveal that all the volcanic sequences display their magmatic ÎŽ18O nature but with D-depleted nature except for the overlying rhyolitic welded tuff, while ores, exclusively localized in the underlying non-welded tuff, are much depleted in both D and ÎŽ18O compared to a protolith, the non-welded tuff. Hydrothermal quartz shows ÎŽ18O values of around 8â°. Kaolinite has a fairly consistent isotope values at ÎŽD of -94 â° and ÎŽ18O of 0.9 â°. Among alteration minerals, chlorite shows isotopically lowest value in ÎŽD of -138 â°, probably due to its Fe-rich composition.
Equilibrium oxygen isotopic fractionation between quartz and kaolinite in ore is indicative of the formation temperature of about 150â , which is consistent with the preservation of marcasite throughout the ore deposit. Pressure prevailing in the alteration process is estimated to be vapor pressure. The fluid-rock interaction is likely to have been isothermal and isobaric process. Isotope-shift and the presence of marcasite in the deposit indicate that the kaolin mineralization occurred under acidic condition (pH < 5).
Fluid flux, which passed through the system during the hydrothermal alteration, is calculated based on the material-balance of K+ between fluid and precursor. The result reveals that the amount of fluid would be as much as 15000 times (in volume) of the host rock.
Infiltration metasomatism is a possible mechanism of the hydrothermal alteration at the Hiraki kaolin deposit. The fluid incurred the non-welded tuff at the inlet of metasomatic column was equilibrium with kaolinite and would have a concentration of log mK+ = -4.29 and log mAl3+ = -11.39 at assumed concentration of log mSiO2 = -2.8 and pH = 4.79. Most of time in the course of alteration, hydrothermal fluid would be slightly undersaturated with respect to muscovite. Non-stoichiometric clays were formed in place of muscovite. It is pointed out that the hydrothermal alteration process could be primarily controlled by composition, especially of a H+ (pH), of the fluid which reacted with the host rock.
Nature of the isotope shift between the host-rock and ores suggests that the water, i. e. ore fluid, reacted with the non-welded tuff would be a mixture of acidic meteoric water with isotope values of ÎŽD = -120â° and ÎŽ18O = -16â°, and magmatic water. Possible existence of meteoric water with such extremely light isotope values in the Hiraki mine area suggests that the Japanese island would be situated at much further north of the present location during the latest Cretaceous to the earliest Tertiary.
During the formation of kaolin deposit, the Hiraki welded tuff served as a cap-rock. Possible sources of magmatic water and heat would be the latest Cretaceous granite intrusions, though not exposed in the mine area, but crop out somewhere in the Hyogo Prefecture. A possible model of formation of the Hiraki kaolin deposit is presented.
** The word "zone" is used as an informal term for the mineral assemblages with indistinctive boundary in spatial distribution
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Granite Petrogenesis in the Cordillera Real, Bolivia and Crustal Evolution in the Central Andes
Isotopic, trace and major element studies of intrusives from the Cordillera Real, Bolivia have identified two distinct granitoid types. Crustally derived granitoids are characterized by high Rb/Sr and Rb/Ba ratios, high degrees of peraluminosity, high eSr and Nd model ages of approximately 1 G a. Granitoids containing a mantle component are characterized by low Rb/Sr and Rb/Ba ratios, peraluminous or metaluminous character, low eSr and younger Nd model ages between 0.5 to 1 Ga.
Sr isotope geochronology has identified two periods of intrusion; late Carboniferous to early Permian and mid Miocene, both times of crustal thickening. Within plate and subduction related mantle components have been identified in specific granitoids on trace element grounds. Both AFC and simple mixing have been identified and quantitatively modelled as processes of combining mantle and crustal components to produce the least evolved samples studied.
The observed evolution of the granitoids was an isotopically closed system process and is modelled as fractional crystallization. The dominant role of accessory phases in controlling the REEs has been quantitatively modelled.
Intra-pluton variations in ESr and ENd can be modelled as either mixing between mantle and crust or episodic crustal remobilization. Individual plutons display homogeneous ESr and heterogeneous ENd values, reflecting the role of xenocrystic accessory phases in preserving the Nd isotope heterogeneity of the source.
The boundary between Hercynian and Andean Orogenies (250 Ma), is marked by: a sharp fall in Nd model ages of magmatic samples, (1 to 0.5 Ga); a fall in the calculated average source Rb/Sr ratio (0.6 to 0.2); and decrease in the inferred crustal reworking rate from between 1.75x Ga-i and 1.2x Ga-i to below 1.2x Ga b All these features reflect an increase in mantle involvement in the Andean orogeny relative to the Hercynian. A second shift in Nd model ages occurs at 25 Ma, the Nd model ages increase back to values comparable to the Hercynian data. Crustal thickening occurred at both these times, the first event probably involved magmatic underplating, the second was a purely intra-crustal event
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