Calculating all elements of minimal index in the infinite parametric family of simplest quartic fields

summary:It is a classical problem in algebraic number theory to decide if a number field is monogeneous, that is if it admits power integral bases. It is especially interesting to consider this question in an infinite parametric family of number fields. In this paper we consider the infinite parametric family of simplest quartic fields $K$ generated by a root $\xi$ of the polynomial $P_t(x)=x^4-tx^3-6x^2+tx+1$, assuming that $t>0$, $t\neq 3$ and $t^2+16$ has no odd square factors. In addition to generators of power integral bases we also calculate the minimal index and all elements of minimal index in all fields in this family

Pressure effects on the transport coefficients of Ba(Fe1-xCox)2As2

We report the temperature dependence of the resistivity and thermoelectric power under hydrostatic pressure of the itinerant antiferromagnet BaFe2As2 and the electron-doped superconductor Ba(Fe0.9Co0.1)2As2. We observe a hole-like contribution to the thermopower below the structural-magnetic transition in the parent compound that is suppressed in magnitude and temperature with pressure. Pressure increases the contribution of electrons to transport in both the doped and undoped compound. In the 10% Co-doped sample, we used a two-band model for thermopower to estimate the carrier concentrations and determine the effect of pressure on the band structure

Implicates dos controles estruturais do depósito caraíbana colocação dos corpos cupríferos do Vale do Curaçá, Bahia - Brasil

O depósito cuprífero Caraíba é o maor dentre diversos corpos de rochas máficas -ultramáficas encontradas no Vale do Curaçá (norte do Estado da Bahia) na parte norte do Cráton do São Francisco. O depósito, que vem sendo explorado desde 1978,consiste de hiperstenito senoritos mineralisados a calcopirita e bornita disseminadas e/ou emagregados disformes. O Valedo Curaçá é um terreno de alto grau metamórfico compreendendo supracrustais, gnaisses do seu provável em basamento e as rochas máficas / ultramáficas colocadas como sills, sendo todas intrudidas por ortognaisses tonalíticos/granodioríticos e granites(G1-G3) Cedo atardi tectônicos a eventos deformacionais altamente dúcteis ocorridos entre 2.25 e 2.05 Ga (idadeUPbdezircões). Eventos final se localisados ocorreram sob fácies xisto verde até cercade 1,9 Ga atrás (isócronaSm-Ndderocha totalem hiperstenitos). A exceção de G2 e G3 todas as rochas já mencionadas apresentam um bandamento metamórfico penetrative (Si) no fácies anfibolito afetado por duas fases de dobramentos respectivamente associados a metamorfismo de fácies granulito e anfibolito. Devido à interferência desses dobramentos mais jovens o depósito Caraíba adquiriu a forma de um cogumelo, com cerca de 5 km de comprimento NS e 800 m de largura EW, e encontra-se alojado em sin forma com piano axial fortemente inclinado para o este e com caimento duplo de eixo para N ou S, fazendo parte do flanco oeste da estrutura maior a antiforma Caraíba. A complexa geometria do depósito, aliada ao intense desmembramento rúptil dúctil que o afetou durante a evolução estrutural da área, tem dificultado o planejamento e as operações de lavra. Uma vez que o corpo mineral atuou como barreira relativamente resistente à de formação intensa e rica em mobilisados da terceira fase, as estruturas da segunda fase puderam ser melhor preservadas nas cercanias de Caraíba, e este fator contribuiu sobre maneira para o entendimento da evolução tectônica do Vale do Curaçá. Os controles estruturais da mineralização cuprífera tem importantes implicações na gênese dos depósitos cupríferos da região, como discutido em detalhe. _______________________________________________________________________________ ABSTRACTThe Caraíba deposit of Bahia, Brazil, is a Paleoproterozoic sill like intrusion consisting of magnetite-bearing hypersthenites, melanorites and norites mainly mineralized with disseminated-type Cu-ore (chalcopyrite and bornite) exploited since 1978. The intrusion is the largest of a set of 100's mafic ultramafic bodies found within the Curaçá Valley terrane,a N-S trending strip of high grade rocks in the northern part of the São Francisco Craton. This terrane comprises supracrustais and gneisses of their probable basement, the maficul tramafic rocks emplaced as sills, all intruded by G1-G3 early-to late-tectonic tonalitic granodioritic orthogneisses and granites related to highly ductile deformation events between 2.25 to 2.05 Ga (U Pb ages of zircons). Final and localized events under greenschist metamorphism lasted up to 1,9 Ga (whole rocks Sm Nd isochron on hypersthenites). A penetrative, layer-parallel amphibolite facies metamorphic banding (Si) occurs in all mentioned rocks-apart from G2 and G3 and is affected by two younger folding events respectively under granulite and amphibolite facies. As a result of this evolution, the Caraíba Cu-deposit is a N-S trending, tight isoclinal and asymmetric F3 synform, with 1000 m of amplitude and axial plane dipping 70°75°to the W, and lies in the western limb of a normal, regional-scale F3 antiform plunging about 18°S. However, because of the interference pattern of F3 with E-W trending F2 folds, the deposit has a nearly 5 km-long and 800 m-wide mushroom shape. Brittle fracturing and boudinage disrupted the orebody throughout the structural evolution, so mining planning and underground exploitation are difficult in some parts of the mine. Because the Caraíba orebody was a relatively rigid barrier to the intense, ductile and melt assisted D3 event,the structural evolution of the Curaçá. Valley terrane is reconstructed with confidence. The evidence for F2 folds in and around the ore-body is better preserved than elsewhere within the Curaçá Valley high grade terrane, where most of the earlier structures were tightened and/or brought intoparallelism with the S3 foliation. The structural controls of Caraíba also bear implications for the genesis of theore body

Lateral Separation of Macromolecules and Polyelectrolytes in Microlithographic Arrays

A new approach to separation of a variety of microscopic and mesoscopic objects in dilute solution is presented. The approach takes advantage of unique properties of a specially designed separation device (sieve), which can be readily built using already developed microlithographic techniques. Due to the broken reflection symmetry in its design, the direction of motion of an object in the sieve varies as a function of its self-diffusion constant, causing separation transverse to its direction of motion. This gives the device some significant and unique advantages over existing fractionation methods based on centrifugation and electrophoresis.Comment: 4 pages with 3 eps figures, needs RevTeX 3.0 and epsf, also available in postscript form http://cmtw.harvard.edu/~deniz

Pressure Induced Quantum Critical Point and Non-Fermi-Liquid Behavior in BaVS3

The phase diagram of BaVS3 is studied under pressure using resistivity measurements. The temperature of the metal to nonmagnetic Mott insulator transition decreases under pressure, and vanishes at the quantum critical point p_cr=20kbar. We find two kinds of anomalous conducting states. The high-pressure metallic phase is a non-Fermi liquid described by Delta rho = T^n where n=1.2-1.3 at 1K < T < 60K. At p<p_cr, the transition is preceded by a wide precursor region with critically increasing resistivity which we ascribe to the opening of a soft Coulomb gap.Comment: 4 pages, 5 eps figures, problem with figure correcte