Transport and spectroscopic properties of superconductor - ferromagnet - superconductor junctions of La1.9Sr0.1CuO4La_{1.9}Sr_{0.1}CuO_4 - La0.67Ca0.33MnO3La_{0.67}Ca_{0.33}MnO_3 - La1.9Sr0.1CuO4La_{1.9}Sr_{0.1}CuO_4

Transport and Conductance spectra measurements of ramp-type junctions made of cuprate superconducting $La_{1.9}Sr_{0.1}CuO_4$ electrodes and a manganite ferromagnetic $La_{0.67}Ca_{0.33}MnO_3$ barrier are reported. At low temperatures below $T_c$, the conductance spectra show Andreev-like broad peaks superposed on a tunneling-like background, and sometimes also sub-gap Andreev resonances. The energy gap values $\Delta$ found from fits of the data ranged mostly between 7-10 mV. As usual, the gap features were suppressed under magnetic fields but revealed the tunneling-like conductance background. After field cycling to 5 or 6 T and back to 0 T, the conductance spectra were always higher than under zero field cooling, reflecting the negative magnetoresistance of the manganite barrier. A signature of superparamagnetism was found in the conductance spectra of junctions with a 12 nm thick LCMO barrier. Observed critical currents with barrier thickness of 12 nm or more, were shown to be an artifact due to incomplete milling of one of the superconducting electrodes.Comment: 10 figure

Attenuation of Noise and Vibration Caused by Underground Trains

Abstract Tunnels are used to convey transportation in dense urban areas, especially by underground trains. Underground trains radiate noise and vibration by airborne sound and by transmission of vibration through the rails to the surrounding ground. The acoustic wave propagates through the ground, being transmitted by soil-structure interactions to nearby buildings. The transportation induced vibrations add to the static and other types of loads, and their specific spectral features are well distinguished and perceived as nuisance to people. The disturbing effect caused by these solid borne vibrations can be significantly mitigated by soil replacement of the material under the rails. This technique, which was described in previous publications by the authors, is further developed and analyzed here by modeling and numerical analysis, for underground applications. Illustrative examples show through spectral analysis the role of soil replacement, avoiding sound bridges. In this context, the required thickness of the soil replacement layer was considered. It is shown that a 0.5 m thick layer may be sufficient for most practical purposes

Organizational Heterogeneity of Vertebrate Genomes

Genomes of higher eukaryotes are mosaics of segments with various structural, functional, and evolutionary properties. The availability of whole-genome sequences allows the investigation of their structure as “texts” using different statistical and computational methods. One such method, referred to as Compositional Spectra (CS) analysis, is based on scoring the occurrences of fixed-length oligonucleotides (k-mers) in the target DNA sequence. CS analysis allows generating species- or region-specific characteristics of the genome, regardless of their length and the presence of coding DNA. In this study, we consider the heterogeneity of vertebrate genomes as a joint effect of regional variation in sequence organization superimposed on the differences in nucleotide composition. We estimated compositional and organizational heterogeneity of genome and chromosome sequences separately and found that both heterogeneity types vary widely among genomes as well as among chromosomes in all investigated taxonomic groups. The high correspondence of heterogeneity scores obtained on three genome fractions, coding, repetitive, and the remaining part of the noncoding DNA (the genome dark matter - GDM) allows the assumption that CS-heterogeneity may have functional relevance to genome regulation. Of special interest for such interpretation is the fact that natural GDM sequences display the highest deviation from the corresponding reshuffled sequences

Mate choice for genetic quality when environments vary: suggestions for empirical progress

Mate choice for good-genes remains one of the most controversial evolutionary processes ever proposed. This is partly because strong directional choice should theoretically deplete the genetic variation that explains the evolution of this type of female mating preferences (the so-called lek paradox). Moreover, good-genes benefits are generally assumed to be too small to outweigh opposing direct selection on females. Here, we review recent progress in the study of mate choice for genetic quality, focussing particularly on the potential for genotype by environment interactions (GEIs) to rescue additive genetic variation for quality, and thereby resolve the lek paradox. We raise five questions that we think will stimulate empirical progress in this field, and suggest directions for research in each area: 1) How is condition-dependence affected by environmental variation? 2) How important are GEIs for maintaining additive genetic variance in condition? 3) How much do GEIs reduce the signalling value of male condition? 4) How does GEI affect the multivariate version of the lek paradox? 5) Have mating biases for high-condition males evolved because of indirect benefits

Avaliação das principais fontes de vibração no meio urbano

No meio urbano existem diversas fontes de vibração que podem gerar a incomodidade ao ser humano, danos estruturais ou prejudicar o funcionamento de equipamentos sensíveis, como os hospitalares, por exemplo. A principal forma de atenuação da energia vibratória é o aumento da distância entre a fonte e o receptor o que vem sendo reduzido sistematicamente pela especulação imobiliária e invasão das áreas de domínio de ferrovias e rodovias. A forma de propagação da energia vibratória depende da fonte, do tipo de solo e da interação entre as ondas de vibração e a estrutura da edificação. As normas técnicas propõem critérios para avaliar a incomodidade dos usuários e danos estruturais das edificações. O parâmetro de análise da vibração é a velocidade da partícula peak (PVP) que é ligada às tensões mecânicas geradas na fundação e estrutura da edificação durante o processo vibratório. O objetivo deste trabalho é avaliar o impacto gerado pelas principais fontes de vibração no meio urbano por meio de medição da velocidade da partícula peak e o cálculo do decaimento da energia vibratória com o aumento da distância. Foram avaliados o tráfego rodoviário, o ferroviário, o processo de cravação de estacas de concreto e metálica e a operação de uma rompedor de concreto movido a ar comprimido. O limite de incomodidade foi superado em todas as análises com exceção da estaca metálica. O limite de danos estruturais foi ultrapassado pelo tráfego ferroviário e operação do bate estacas