On wild extensions of a p-adic field

In this paper we consider the problem of classifying the isomorphism classes of extensions of degree pk of a p-adic field, restricting to the case of extensions without intermediate fields. We establish a correspondence between the isomorphism classes of these extensions and some Kummer extensions of a suitable field F containing K. We then describe such classes in terms of the representations of Gal(F/K). Finally, for k = 2 and for each possible Galois group G, we count the number of isomorphism classes of the extensions whose normal closure has a Galois group isomorphic to G. As a byproduct, we get the total number of isomorphism classes

Applying the proto-theory of design to explain and modify the parameter analysis method of conceptual design

This article reports on the outcomes of applying the notions provided by the reconstructed proto-theory of design, based on Aristotle’s remarks, to the parameter analysis (PA) method of conceptual design. Two research questions are addressed: (1) What further clarification and explanation to the approach of PA is provided by the proto-theory? (2) Which conclusions can be drawn from the study of an empirically derived design approach through the proto-theory regarding usefulness, validity and range of that theory? An overview of PA and an application example illustrate its present model and unique characteristics. Then, seven features of the proto-theory are explained and demonstrated through geometrical problem solving and analogies are drawn between these features and the corresponding ideas in modern design thinking. Historical and current uses of the terms analysis and synthesis in design are also outlined and contrasted, showing that caution should be exercised when applying them. Consequences regarding the design moves, process and strategy of PA allow proposing modifications to its model, while demonstrating how the ancient method of analysis can contribute to better understanding of contemporary design-theoretic issues

Santa María de la Sierra: una curiosa opción ornamental dentro del Císter castellanoleonés

Despite the well known Cistercian reluctance to figurative representation in their monasteries, the vegetal ornamental patterns precept was not as preferred as thought nor it was as honoured as expected in some of them. One of the exceptions that prove the rule to Cistercian aniconism is found in the very humble church of Santa María de la Sierra-Sotosalbos (Collado Hermoso, Segovia); this discrete abbatial temple holds in its ruins –and among its vegetal capitals- a small zoological collection of birds, lions and hares capable of significantly enriching the repertoire used by this religious order, demonstrating that the importance of ornamental models itinerancy and the influence of the geographically nearby and historically precedent Romanic options –even the contemporary Romanic- was stronger than thought, taking to pieces the unfounded theory –backed by many authors- of the existence of the so called “Cistercian Style”.A pesar de las conocidas reticencias del Císter a la representación figurativa dentro de sus monasterios, en algunos de ellos la opción ornamental de tipo vegetal no fue tan preferente como se cree, ni tan respetada como cabría esperar. Una de esas excepciones que confirman la regla del aniconismo cisterciense es la modestísima iglesia de Santa María de la Sierra-Sotosalbos (Collado Hermoso, Segovia). Este discreto templo abacial custodia entre sus ruinas –y entre sus capiteles vegetales– un pequeño muestrario zoológico de aves, leones y liebres, capaz de enriquecer significativamente el repertorio empleado por esta Orden religiosa, demostrando la importancia de la itinerancia de modelos y la influencia de las opciones del románico geográficamente circundante e inmediatamente precedente –o incluso contemporáneo–, que fue más fuerte de lo que se piensa, desmontando la teoría infundada –y respaldada por muchos autores– de la existencia del llamado “estilo cisterciense”

Variabilidade do "upwelling" costeiro durante o holocénico nas margens atlânticas ocidental e meridional da Península Ibérica

Tese de dout., Ciências do Mar, Faculdade de Ciências do Mar e do Ambiente, Univ. do Algarve, 2005O estudo levado a cabo permitiu, pela primeira vez, identificar os eventos de frio 5 e 4 de Bond e o de 0,8 ka cal BP de deMenocal nos teores em radiocarbono das conchas e confirmá-los como fenómenos à escala global (circum-atlântico norte). Esses eventos revelam-se por valores positivos muito elevados de ΔR e são precursores de reorganizações climáticas. Os dois primeiros, datados de 7810±90 BP e de 5640±100 BP, respectivamente, foram apenas detectados na série de valores de ΔR (e de 13) determinados para a costa portuguesa, uma vez que as séries para a costa andaluza e para a costa galega se iniciam em 4580±110 BP, a primeira, e em 2440±29 BP, a segunda. O evento de frio de 0,8 ka foi determinado quer para a costa portuguesa quer para a costa galega com datas estatisticamente idênticas – costa portuguesa: 870±90 BP; costa galega: 860±90 BP. Além dos picos de ΔR correspondentes a estes três eventos, dois outros picos foram obtidos: um, datado por volta de 4000 BP e um outro cerca de 1100 BP. O primeiro, detectado quer para a costa portuguesa quer para a orla oriental do Golfo de Cádiz, deverá ser a tradução de um “upwelling” costeiro muito intenso, uma vez que o 13C das conchas analisadas apresenta valores positivos ao contrário do que sucede com os outros picos. Além disso, entre 4000 e 3200 BP terá havido uma época de secura, com expansão de espécies termomediterrâneas no noroeste alentejano, enquanto que no sudeste e, possivelmente, também no sudoeste espanhol, o intervalo de 4500 e 4000 BP, corresponderá a uma época de aridez e, por conseguinte, a uma insolação intensa, que se traduziu no aparecimento e intensificação do fenómeno do “upwelling” costeiro, como os valores positivos de ΔR que acompanham o pico de ca. 4000 BP da série andaluza sugerem. Então os dois picos aparentemente síncronos não o serão, tendo lugar, entre eles, uma reorganização climática cujo mecanismo forçador terá sido o evento 3 de Bond. O outro pico, em 1140±45 BP, foi só detectado na costa portuguesa, possivelmente ligado à reorganização climática que originou o Pequeno Óptimo Climático e o seu valor não resultará de qualquer intensificação do “upwelling” nesse momento. A análise das séries de valores de ΔR em função do tempo, conjugada com outros indicadores paleoclimáticos e paleoceanográficos, permitem ainda as seguintes conclusões: i) Entre o evento 8 de Bond (ca. 11100 cal BP) e o final do Pré-Boreal (até ao evento 7, ca. 10300 cal BP) terá existido na costa portuguesa um regime de “upwelling” costeiro, cuja intensidade terá aumentado ao longo desse período. ii) Durante o Boreal, a que corresponde um clima frio, terá ocorrido entre o evento 6 (ca. 9,4 ka cal BP) e o 5 (ca. 8,2 ka cal BP) um “upwelling” costeiro pouco activo ou mesmo inexistente, como os valores negativos para ΔR indiciam. iii) Os intervalos de tempo entre os eventos 5 e 4 (ca. 5,9 ka cal BP) e entre este e o 3 (ca. 4,2 ka cal BP ou ca. 4000 BP) encontram-se muito mal amostrados, pelo que quaisquer inferências deverão ser posteriormente validadas com mais dados. No entanto, com a reorganização climática associada ao evento “8,2 ka”, assiste-se a uma modificação no padrão de povoamento mesolítico na faixa costeira portuguesa, provavelmente relacionada com uma melhoria do clima (um aquecimento climático), pelo que será expectável um “upwelling” costeiro activo, embora fraco, como os dois únicos valores de ΔR determinados para o primeiro intervalo também sugerem. Para o segundo intervalo, para a costa portuguesa, para um momento próximo do seu final (4530-4830 cal BP), foi obtido um valor de ΔR negativo, ao contrário do que se obteve para o Golfo de Cádiz, o que sugere condições climáticas diferentes entre a fachada atlântica ocidental da Península (diminuição da temperatura, menor insolação das massas continentais) e o sudoeste espanhol (aridez, maior insolação). De qualquer modo, após a reorganização climática que o evento 3 terá provocado, num momento muito próximo, não possível de distinguir com as datas de radiocarbono obtidas, ter-se-á verificado uma intensificação do “upwelling” na costa portuguesa, que se traduziu por um máximo na série de ΔRs, enquanto que, com essa reorganização climática, terminou o período de cerca de 500 anos de existência de um “upwelling” activo na costa andaluza do Golfo de Cádiz, para não mais esse fenómeno voltar a ocorrer de um modo activo naquela orla costeira. iv) O período entre 4000 e 3000 BP, a que corresponderá um clima mais quente e seco do que o anterior para a costa portuguesa, com expansão de taxa termomediterrâneos, deverá caracterizar-se por um “upwelling” costeiro intenso e, por conseguinte, por valores altos de ΔR. No entanto, a inexistência da determinação de qualquer valor de ΔR para este intervalo de tempo, quer para a costa portuguesa, quer para a costa andaluza do Golfo de Cádiz, quer para a costa ocidental galega, torna impossível corroborar as inferências anteriores. v) Pelo contrário, a partir de 3000 BP dispôe-se de uma boa amostragem para a costa portuguesa e razoável para os outros troços de costa investigados. Verifica-se que, na costa galega, ao contrário do que sucede para a costa portuguesa, os valores de ΔR são todos negativos até ca. 1000 cal AD, o que sugere um “upwelling” inexistente ou, quando muito, de fraca intensidade. O mesmo acontecerá para a costa andaluza, embora aqui essa situação ocorra muito provavelmente desde 4000 BP e se prolongue até à actualidade. Para a costa portuguesa, a partir de 3000 BP terá existido um “upwelling” activo, mas menos intenso que o actual, excepto durante o Pequeno Óptimo Climático, quando se terá aproximado dos valores modernos. Por seu lado, na costa galega, a partir do pico de ca. 1000 cal AD, isto é, a partir da reorganização climática desencadeada por esse evento, observa-se o aparecimento e intensificação do “upwelling” costeiro, embora dentro de uma certa variabilidade como os valores positivos e negativos determinados para ΔR sugerem. A grande variabilidade climática do Holocénico, com uma dimensão insuspeitada até à poucos anos atrás (por ex., os eventos de frio foram apenas identificados e estudados a partir dos meados dos anos noventa), tem, como este estudo demonstra, reflexos profundos na intensidade do “upwelling” costeiro nas margens atlânticas ocidental e meridional da Península Ibérica. Deverá sublinhar-se que esta dissertação constitui o estudo mais completo até hoje efectuado sobre o efeito de reservatório oceânico e que este é o “proxy” que proporciona o sinal mais directo sobre a actividade do “upwelling” costeiro

Reduction of the formaldehyde content in leathers treated with formaldehyde resins by means of plant polyphenols

Formaldehyde has applications in many industrial processes, including synthesis of resins and syntans to be used in the retanning process of leather. When resins are employed, they can hydrolyse, releasing formaldehyde. Due to the carcinogenicity of formaldehyde, its presence in leather should be avoided or kept below allowable limits. The aim of this study is to determine the effect of polyphenols contained in vegetable compounds (mimosa, quebracho and tara) in the reduction of the formaldehyde content in leathers treated with resins synthesized with formaldehyde (melamine-formaldehyde and dicyandiamide-formaldehyde). The formaldehyde content in leathers treated only with resin increases with time while the formaldehyde content in leathers treated additionally with vegetable compounds is reduced. The lower the formaldehyde content in the leather, the higher the ability of vegetable compounds to reduce such content. Mimosa shows the strongest ability to reduce the formaldehyde content, and this capacity increases with ageing. The addition of 4% (on shaved wet-blue weight) of mimosa gives rise to an 85% reduction in the formaldehyde content 140 days after leather processing of split hides treated with a formaldehyde resin of low formaldehyde content. However, this reduction is 68% in splits hides treated with a resin of high formaldehyde content. This is of great importance in baby’s leather articles, in which the formaldehyde content is low; therefore, the addition of a small amount (3%) of vegetable compounds (especially mimosa) guarantees that the formaldehyde content is below the allowed limits (16 mg/kg in the most restrictive regulation). Reducing the formaldehyde content using the polyphenols contained in vegetable compounds constitutes a good alternative not only in the leather sector but also in other industrial sectors (wood, textile, etc.) that use formaldehyde resins.Peer ReviewedPostprint (published version

HYBRID SYSTEMS: COLD ATOMS COUPLED TO MICRO MECHANICAL OSCILLATORS

Micro mechanical oscillators can serve as probes in precision measurements, as transducersto mediate photon-phonon interactions, and when functionalized with magneticmaterial, as tools to manipulate spins in quantum systems. This dissertationincludes two projects where the interactions between cold atoms and mechanical oscillatorsare studied.In one of the experiments, we have manipulated the Zeeman state of magneticallytrapped Rubidium atoms with a magnetic micro cantilever [1]. The results show aspatially localized effect produced by the cantilever that agrees with Landau-Zenertheory. In the future, such a scalable system with highly localized interactions andthe potential for single-spin sensitivity could be useful for applications in quantuminformation science or quantum simulation.In a second experiment, work is in progress to couple a sample of optically trappedRubidium atoms to a levitated nanosphere via an optical lattice [2]. This couplingenables the cooling of the center-of-mass motion of the nanosphere by laser coolingthe atoms. In this system, the atoms are trapped in the optical lattice while thesphere is levitated in a separate vacuum chamber by a single-beam optical tweezer.Theoretical analysis of such a system has determined that cooling the center-of-massmotion of the sphere to its quantum ground state is possible, even when starting atroom temperature, due to the excellent environmental decoupling achievable in thissetup. Nanospheres cooled to the quantum regime can provide new tests of quantumbehavior at mesoscopic scales and have novel applications in precision sensing

Social dynamics in conferences: analyses of data from the Live Social Semantics application

Popularity and spread of online social networking in recent years has given a great momentum to the study of dynamics and patterns of social interactions. However, these studies have often been confined to the online world, neglecting its interdependencies with the offline world. This is mainly due to the lack of real data that spans across this divide. The Live Social Semantics application is a novel platform that dissolves this divide, by collecting and integrating data about people from (a) their online social networks and tagging activities from popular social networking sites, (b) their publications and co-authorship networks from semantic repositories, and (c) their real-world face-to-face contacts with other attendees collected via a network of wearable active sensors. This paper investigates the data collected by this application during its deployment at three major conferences, where it was used by more than 400 people. Our analyses show the robustness of the patterns of contacts at various conferences, and the influence of various personal properties (e.g. seniority, conference attendance) on social networking patterns

Evolution and excitation conditions of outflows in high-mass star-forming regions

Theoretical models suggest that massive stars form via disk-mediated accretion, with bipolar outflows playing a fundamental role. A recent study toward massive molecular outflows has revealed a decrease of the SiO line intensity as the object evolves. The present study aims at characterizing the variation of the molecular outflow properties with time, and at studying the SiO excitation conditions in outflows associated with massive YSOs. We used the IRAM30m telescope to map 14 massive star-forming regions in the SiO(2-1), SiO(5-4) and HCO+(1-0) outflow lines, and in several dense gas and hot core tracers. Hi-GAL data was used to improve the spectral energy distributions and the L/M ratio, which is believed to be a good indicator of the evolutionary stage of the YSO. We detect SiO and HCO+ outflow emission in all the sources, and bipolar structures in six of them. The outflow parameters are similar to those found toward other massive YSOs. We find an increase of the HCO+ outflow energetics as the object evolve, and a decrease of the SiO abundance with time, from 10^(-8) to 10^(-9). The SiO(5-4) to (2-1) line ratio is found to be low at the ambient gas velocity, and increases as we move to high velocities, indicating that the excitation conditions of the SiO change with the velocity of the gas (with larger densities and/or temperatures for the high-velocity gas component). The properties of the SiO and HCO+ outflow emission suggest a scenario in which SiO is largely enhanced in the first evolutionary stages, probably due to strong shocks produced by the protostellar jet. As the object evolves, the power of the jet would decrease and so does the SiO abundance. During this process, however, the material surrounding the protostar would have been been swept up by the jet, and the outflow activity, traced by entrained molecular material (HCO+), would increase with time.Comment: 31 pages, 10 figures and 5 tables (plus 2 figures and 3 tables in the appendix). Accepted for publication in A&A. [Abstract modified to fit the arXiv requirements.