Compositional analysis of archaeological glasses

At CoDaWork'03 we presented work on the analysis of archaeological glass composi-tional data. Such data typically consist of geochemical compositions involving 10-12variables and approximates completely compositional data if the main component, sil-ica, is included. We suggested that what has been termed `crude' principal componentanalysis (PCA) of standardized data often identi ed interpretable pattern in the datamore readily than analyses based on log-ratio transformed data (LRA). The funda-mental problem is that, in LRA, minor oxides with high relative variation, that maynot be structure carrying, can dominate an analysis and obscure pattern associatedwith variables present at higher absolute levels. We investigate this further using sub-compositional data relating to archaeological glasses found on Israeli sites. A simplemodel for glass-making is that it is based on a `recipe' consisting of two `ingredients',sand and a source of soda. Our analysis focuses on the sub-composition of componentsassociated with the sand source. A `crude' PCA of standardized data shows two clearcompositional groups that can be interpreted in terms of di erent recipes being used atdi erent periods, reected in absolute di erences in the composition. LRA analysis canbe undertaken either by normalizing the data or de ning a `residual'. In either case,after some `tuning', these groups are recovered. The results from the normalized LRAare di erently interpreted as showing that the source of sand used to make the glassdi ered. These results are complementary. One relates to the recipe used. The otherrelates to the composition (and presumed sources) of one of the ingredients. It seemsto be axiomatic in some expositions of LRA that statistical analysis of compositionaldata should focus on relative variation via the use of ratios. Our analysis suggests thatabsolute di erences can also be informative

Llenguatges de consulta a l'àmbit de la Web Semàntica : Cas d'estudi SPARQL

El projecte es basa en estudiar i avaluar diferents sistemes gestors de bases de dades (SGBDs) per desar informació dins el context de la Web Semàntica. Els SGBDs hauran de tractar, emmagatzemar i gestionar la informació classificada segons uns criteris semàntics i interrelacionada amb conceptes afins, alhora que permetin la comunicació entre sistemes de manera transparent a l'usuari.

Impacte de les tecnologies de la informació i la comunicació en l’Administració de justícia: modernització i eficiència

L’Administració de Justícia, com servei públic que ha de donar als ciutadans una eficaç resolució dels conflictes, ha de comptar per al correcte compliment de la seva funció institucional, amb una sèrie de mitjans, no tan sols personals i materials, sinó també tecnològics, que li permetin assegurar la consecució de les seves finalitats. Per tant, es precisa una Administració oberta i transparent, caracteritzada per l’efectivitat i per la seva proximitat al ciutadà. La introducció de les TIC en l’Administració de Justícia és un procés bastant recent i encara no tancat, si es compara amb la resta del sector públic, especialment d’altres àmbits de l’Administració molt més avançats en la incorporació de les TIC, com són el tributari i el de la Seguretat Social. No obstant això, avui en dia, on majors èxits s’han assolit en aquest camp en l’Administració de Justícia és en el de la seva utilització interna: informatització interna, gestió interna dels procediments, intranets, etc. Per això, on queda un llarg camí per recórrer encara és en el camp de les relacions telemàtiques entre Administració de Justícia i els operadors jurídics, però especialment amb els ciutadans. D’altra banda, el legislador és sensible cada vegada més a aquest tema i s’ha preocupat de regular determinats aspectes on les TIC incideixen en l’àmbit de la justícia: actuacions dels procuradors, advocats, notificacions telemàtiques, el valor del document electrònic en el procés judicial... Així queda reflectit, per exemple, a la Llei Orgànica del Poder Judicial o la Llei d’Enjudiciament Civil. No obstant això, de lege ferenda, seria convenient l’existència d’un marc normatiu únic regulador de l’aplicació de les TIC en la Justícia. Així mateix, també ha d’assenyalar-se que en el procés institucional d’introducció de les noves tecnologies en la Justícia alguns dels acords adoptats així com les previsions contingudes en la normativa aplicable, no deixen de ser en la majoria dels casos simplement programàtics.

Studies in stoichiometry with compositional data

Geochemical data that is derived from the whole or partial analysis of various geologic materialsrepresent a composition of mineralogies or solute species. Minerals are composed of structuredrelationships between cations and anions which, through atomic and molecular forces, keep the elementsbound in specific configurations. The chemical compositions of minerals have specific relationships thatare governed by these molecular controls. In the case of olivine, there is a well-defined relationshipbetween Mn-Fe-Mg with Si. Balances between the principal elements defining olivine composition andother significant constituents in the composition (Al, Ti) have been defined, resulting in a near-linearrelationship between the logarithmic relative proportion of Si versus (MgMnFe) and Mg versus (MnFe),which is typically described but poorly illustrated in the simplex.The present contribution corresponds to ongoing research, which attempts to relate stoichiometry andgeochemical data using compositional geometry. We describe here the approach by which stoichiometricrelationships based on mineralogical constraints can be accounted for in the space of simplicialcoordinates using olivines as an example. Further examples for other mineral types (plagioclases andmore complex minerals such as clays) are needed. Issues that remain to be dealt with include thereduction of a bulk chemical composition of a rock comprised of several minerals from which appropriatebalances can be used to describe the composition in a realistic mineralogical framework. The overallobjective of our research is to answer the question: In the cases where the mineralogy is unknown, arethere suitable proxies that can be substituted?Kew words: Aitchison geometry, balances, mineral composition, oxides

The CFSP/ESDP, Parliamentary Accountability, and the ´Future of Europe´ Convention debate

This paper examines the importance that the current Convention on the Future of Europe is giving (or not) to the question of democratic accountability in European foreign and defence policy. As all European Union (EU) member states are parliamentary democracies1, and as there is a European Parliament (EP) which also covers CFSP (Common Foreign and Security Policy) and ESDP (European Security and Defence Policy2) matters, I will concentrate on parliamentary accountability rather than democratic accountability more widely defined. Where appropriate, I will also refer to the work of other transnational parliamentary bodies such as the North Atlantic Assembly or NAA (NATO´s Parliamentary Assembly) or the Western European Union (WEU) Parliamentary Assembly3. The article will consist of three sections. First, I will briefly put the question under study within its wider context (section 1). Then, I will examine the current level of parliamentary accountability in CFSP and defence matters (section 2). Finally, I will consider the current Convention debate and assess how much attention is being given to the question of accountability in foreign and defence policies (section 3). This study basically argues that, once again, there is very little interest in an issue that should be considered as vital for the future democratic development of a European foreign and defence policy. It is important to note however that this paper does not cover the wider debate about how to democratise and make the EU more transparent and closer to its citizens. It concentrates on its Second Pillar because its claim is that very little if any attention is being given to this question

Grain size analyses in tin-lead glazes based on 2d-sections

A problem in the archaeometric classification of Catalan Renaissance pottery is the fact, thatthe clay supply of the pottery workshops was centrally organized by guilds, and thereforeusually all potters of a single production centre produced chemically similar ceramics.However, analysing the glazes of the ware usually a large number of inclusions in the glaze isfound, which reveal technological differences between single workshops. These inclusionshave been used by the potters in order to opacify the transparent glaze and to achieve a whitebackground for further decoration.In order to distinguish different technological preparation procedures of the single workshops,at a Scanning Electron Microscope the chemical composition of those inclusions as well astheir size in the two-dimensional cut is recorded. Based on the latter, a frequency distributionof the apparent diameters is estimated for each sample and type of inclusion.Following an approach by S.D. Wicksell (1925), it is principally possible to transform thedistributions of the apparent 2D-diameters back to those of the true three-dimensional bodies.The applicability of this approach and its practical problems are examined using differentways of kernel density estimation and Monte-Carlo tests of the methodology. Finally, it istested in how far the obtained frequency distributions can be used to classify the pottery

Aegis : Conexión a bases de datos distribuidas

Esta aplicación pretende ser en un cliente ligero de conexión a las distintas bases de datos, de tal forma que, de manera transparente y simplemente seleccionando un esquema de ejecución, se permitan consultas tanto de forma online como programada.

Vibration and two-photon absorption

The rigorous and transparent treatment of the effects of nuclear vibrational motion in two-photon absorption (TPA) was discussed. Perturbation formula for diatomic molecules were developed and applied to the X¹Σ+–A¹Π transition in CO. The analysis showed that the vibrations played an important role in TPA, just as their role in the calculation of conventional nonlinear optical (NLO) hyperpolarizabilities

Oxidation of silicon: further tests for the interfacial silicon emission model

The classical description of Si oxidation given by Deal and Grove has well-known limitations for thin oxides (below 200 Ã). Among the large number of alternative models published so far, the interfacial emission model has shown the greatest ability to fit the experimental oxidation curves. It relies on the assumption that during oxidation Si interstitials are emitted to the oxide to release strain and that the accumulation of these interstitials near the interface reduces the reaction rate there. The resulting set of differential equations makes it possible to model diverse oxidation experiments. In this paper, we have compared its predictions with two sets of experiments: (1) the pressure dependence for subatmospheric oxygen pressure and (2) the enhancement of the oxidation rate after annealing in inert atmosphere. The result is not satisfactory and raises serious doubts about the model’s correctness

The effect of atmospheric absorption of sunlight on the runaway greenhouse point

The longwave emission of planetary atmospheres that contain a condensable absorbing gas in the infrared (i.e., longwave), which is in equilibrium with its liquid phase at the surface, may exhibit an upper bound. Here we analyze the effect of the atmospheric absorption of sunlight on this radiation limit. We assume that the atmospheric absorption of infrared radiation is independent of wavelength except within the spectral width of the atmospheric window, where it is zero. The temperature profile in radiative equilibrium is obtained analytically as a function of the longwave optical thickness. For illustrative purposes, numerical values for the infrared atmospheric absorption (i.e., greenhouse effect) and the liquid vapor equilibrium curve of the condensable absorbing gas refer to water. Values for the atmospheric absorption of sunlight (i.e., antigreenhouse effect) take a wide range since our aim is to provide a qualitative view of their effects. We find that atmospheres with a transparent region in the infrared spectrum do not present an absolute upper bound on the infrared emission. This result may be also found in atmospheres opaque at all infrared wavelengths if the fraction of absorbed sunlight in the atmosphere increases with the longwave opacity

Economia digital : una sortida per a múltiples sistemes comercials

Economia Digital: Una sortida per a múltiples sistemes comercials, és un treball de recerca que tracta sobre el comerç electrònic en tots els seus aspectes, partint d’un anàlisi teòric que estableix les bases d’aquest sistema comercial; seguit d’un estudi de dos casos concrets d’empreses que han introduït Internet en la seva activitat. Per una banda, una d’aquestes empreses, Destil·leries Julián Segarra, s’ha servit de les noves tecnologies, amb un ús publicitari, per tal de donar-se a conèixer però sense oferir la possibilitat de venda online. D’altra banda, Surfdevils S.L. no només utilitza els recursos que ofereix la xarxa de manera informativa, sinó que va més enllà i permet adquirir els seus productes mitjançant el seu espai web. A més es realitza un breu estudi sobre els hàbits de compra per Internet, mitjançant una enquesta efectuada a una mostra de la població.Tot aquest estudi, serveix per arribar a la conclusió que introduir el comerç electrònic dins del seu funcionament és rentable per a les empreses i beneficiós pels consumidors, ja que els ofereix la possibilitat d’adquirir els productes en un mercat més ampli, transparent i competitiu.

ILS-ESP An efficient, simple, and parameter-free algorithm for solving the permutation flow-shop problem

From a managerial point of view, the more effcient, simple, and parameter-free (ESP) an algorithm is, the more likely it will be used in practice for solving real-life problems. Following this principle, an ESP algorithm for solving the Permutation Flowshop Sequencing Problem (PFSP) is proposed in this article. Using an Iterated Local Search (ILS) framework, the so-called ILS-ESP algorithm is able to compete in performance with other well-known ILS-based approaches, which are considered among the most effcient algorithms for the PFSP. However, while other similar approaches still employ several parameters that can affect their performance if not properly chosen, our algorithm does not require any particular fine-tuning process since it uses basic "common sense" rules for the local search, perturbation, and acceptance criterion stages of the ILS metaheuristic. Our approach defines a new operator for the ILS perturbation process, a new acceptance criterion based on extremely simple and transparent rules, and a biased randomization process of the initial solution to randomly generate different alternative initial solutions of similar quality -which is attained by applying a biased randomization to a classical PFSP heuristic. This diversification of the initial solution aims at avoiding poorly designed starting points and, thus, allows the methodology to take advantage of current trends in parallel and distributed computing. A set of extensive tests, based on literature benchmarks, has been carried out in order to validate our algorithm and compare it against other approaches. These tests show that our parameter-free algorithm is able to compete with state-of-the-art metaheuristics for the PFSP. Also, the experiments show that, when using parallel computing, it is possible to improve the top ILS-based metaheuristic by just incorporating to it our biased randomization process with a high-quality pseudo-random number generator.

Reversible ferromagnetic switching in ZnO:(Co,Mn) powders

We report here on the magnetic properties of ZnO:Mn- and ZnO:Co-doped nanoparticles. We have found that the ferromagnetism of ZnO:Mn can be switched on and off by consecutive low-temperature annealings in O2 and N2, respectively, while the opposite phenomenology was observed for ZnO:Co. These results suggest that different defects (presumably n-type for ZnO:Co and p-type for ZnO:Mn) are required to induce a ferromagnetic coupling in each case. We will argue that ferromagnetism is likely to be restricted to a very thin, nanometric layer at the grain surface. These findings reveal and give insight into the dramatic relevance of surface effects to the occurrence of ferromagnetism in ZnO-doped oxides.

Ophiolite-related ultramafic rocks (Serpentinites) in the Caribbean region: a review of their occurrence, composition, origin, emplacements and Ni-Laterite soil formation

Ultramafic rocks, mainly serpentinized peridotites of mantle origin, are mostly associated with the ophiolites of Mesozoic age that occur in belts along three of the margins of the Caribbean plate. The most extensive exposures are in Cuba. The ultramafic-mafic association (ophiolites) were formed and emplaced in several different tectonic environments. Mineralogical studies of the ultramafic rocks and the chemistry of the associated mafic rocks indicate that most of the ultramafic-mafic associations in both the northern and southern margins of the plate were formed in arc-related environments. There is little mantle peridotite exposed in the ophiolitic associations of the west coast of Central America, in the south Caribbean in Curacao and in the Andean belts in Colombia. In these occurrences the chemistry and age of the mafic rocks indicates that this association is mainly part of the 89 Ma Caribbean plateau province. The age of the mantle peridotites and associated ophiolites is probably mainly late Jurassic or Early Cretaceous. Emplacement of the ophiolites possibly began in the Early Cretaceous in Hispaniola and Puerto Rico, but most emplacement took place in the Late Cretaceous to Eocene (e.g. Cuba). Along the northern South America plate margin, in the Caribbean mountain belt, emplacement was by major thrusting and probably was not completed until the Oligocene or even the early Miocene. Caribbean mantle peridotites, before serpentinization, were mainly harzburgites, but dunites and lherzolites are also present. In detail, the mineralogical and chemical composition varies even within one ultramafic body, reflecting melting processes and peridotite/melt interaction in the upper mantle. At least for the northern Caribbean, uplift (postemplacement tectonics) exposed the ultramafic massifs as a land surface to effective laterization in the beginning of the Miocene. Tectonic factors, determining the uplift, exposing the peridotites to weathering varied. In the northern Caribbean, in Guatemala, Jamaica, and Hispaniola, uplift occurred as a result of transpresional movement along pre-existing major faults. In Cuba, uplift occurred on a regional scale, determined by isostatic adjustment. In the south Caribbean, uplift of the Cordillera de la Costa and Serrania del Interior exposing the peridotites, also appears to be related to strike-slip movement along the El Pilar fault system. In the Caribbean, Ni-laterite deposits are currently being mined in the central Dominican Republic, eastern Cuba, northern Venezuela and northwest Colombia. Although apparently formed over ultramafic rocks of similar composition and under similar climatic conditions, the composition of the lateritic soils varies. Factors that probably determined these differences in laterite composition are geomorphology, topography, drainage and tectonics. According to the mineralogy of principal ore-bearing phases, Dominican Ni-laterite deposits are classified as the hydrous silicate-type. The main Ni-bearing minerals are hydrated Mg-Ni silicates (serpentine and ¿garnierite¿) occurring deeper in the profile (saprolite horizon). In contrast, in the deposits of eastern Cuba, the Ni and Cooccurs mainly in the limonite zone composed of Fe hydroxides and oxides as the dominant mineralogy in the upper part of the profile, and are classified as the oxide-type.

X-ray photoelectron spectroscopy analysis of ion¿beam¿induced oxidation of GaAs and AlGaAs

The oxidation of GaAs and AlGaAs targets subjected to O2+ bombardment has been analyzed, using in situ x¿ray photoelectron spectroscopy, as a function of time until steady state is reached. The oxides formed by the O2+ bombardment have been characterized in terms of composition and binding energy. A strong energy and angular dependence for the oxidation of As relative to Ga is found. Low energies as well as near normal angles of incidence favor the oxidation of As. The difference between Ga and As can be explained in terms of the formation enthalpy for the oxide and the excess supply of oxygen. In an AlGaAs target the Al is very quickly completely oxidized irrespective of the experimental conditions. The steady state composition of the altered layers show in all cases a preferential removal of As.