Decoherence in a Josephson junction qubit

The zero-voltage state of a Josephson junction biased with constant current consists of a set of metastable quantum energy levels. We probe the spacings of these levels by using microwave spectroscopy to enhance the escape rate to the voltage state. The widths of the resonances give a measurement of the coherence time of the two states involved in the transitions. We observe a decoherence time shorter than that expected from dissipation alone in resonantly isolated 20 um x 5 um Al/AlOx/Al junctions at 60 mK. The data is well fit by a model including dephasing effects of both low-frequency current noise and the escape rate to the continuum voltage states. We discuss implications for quantum computation using current-biased Josephson junction qubits, including the minimum number of levels needed in the well to obtain an acceptable error limit per gate.Comment: 4 pages, 6 figure

Direct determination of Pb isotope ratios in archaeological materials by coupling liquid chromatography to multicollector ICP-MS

A procedure for the determination of Pb isotope ratios by coupling liquid chromatography to a multicollector ICP-MS has been developed. The procedure allows the direct injection of samples after dissolution without resorting to time-consuming off-line separation procedures. The separation of Pb from concomitant elements is carried out by anionic exchange as ethylenediamine tetraacetic acid (EDTA) chelates using EDTA and ammonium nitrate as a mobile phase. A flow injection system allows the injection of NIST 981 Pb isotopic standard, before and after the Pb peak from the sample, and the on-line addition of Tl for mass bias correction and bracketing. The procedure was validated by injecting NIST 981 into the chromatographic system and by comparing the results for real samples with the classical off-line separation procedure using Pb spec resins. The optimised procedure was applied to archaeological samples containing different concentrations of Pb. It was observed that the only limitation to the accuracy of the procedure was the concentration of Pb in the samples as no preconcentration is performed. Solid archaeological samples containing at least 500 μg g−1 of Pb can be studied using the proposed procedure

Mid-infrared imaging- and spectro-polarimetric subarcsecond observations of NGC 1068

We present sub-arcsecond 7.5$-$13 $\mu$m imaging- and spectro-polarimetric observations of NGC 1068 using CanariCam on the 10.4-m Gran Telescopio CANARIAS. At all wavelengths, we find: (1) A 90 $\times$ 60 pc extended polarized feature in the northern ionization cone, with a uniform $\sim$44$^{\circ}$ polarization angle. Its polarization arises from dust and gas emission in the ionization cone, heated by the active nucleus and jet, and further extinguished by aligned dust grains in the host galaxy. The polarization spectrum of the jet-molecular cloud interaction at $\sim$24 pc from the core is highly polarized, and does not show a silicate feature, suggesting that the dust grains are different from those in the interstellar medium. (2) A southern polarized feature at $\sim$9.6 pc from the core. Its polarization arises from a dust emission component extinguished by a large concentration of dust in the galaxy disc. We cannot distinguish between dust emission from magnetically aligned dust grains directly heated by the jet close to the core, and aligned dust grains in the dusty obscuring material surrounding the central engine. Silicate-like grains reproduce the polarized dust emission in this feature, suggesting different dust compositions in both ionization cones. (3) An upper limit of polarization degree of 0.3 per cent in the core. Based on our polarization model, the expected polarization of the obscuring dusty material is $\lesssim$0.1 per cent in the 8$-$13 $\mu$m wavelength range. This low polarization may be arising from the passage of radiation through aligned dust grains in the shielded edges of the clumps.Comment: 17 pages, 10 figures, accepted for publication at MNRA

Connecting Metainflammation and Neuroinflammation Through the PTN-MK-RPTPβ/ζ Axis: Relevance in Therapeutic Development

Inflammation is a common factor of pathologies such as obesity, type 2 diabetes or neurodegenerative diseases. Chronic inflammation is considered part of the pathogenic mechanisms of different disorders associated with aging. Interestingly, peripheral inflammation and the associated metabolic alterations not only facilitate insulin resistance and diabetes but also neurodegenerative disorders. Therefore, the identification of novel pathways, common to the development of these diseases, which modulate the immune response and signaling is key. It will provide highly relevant information to advance our knowledge of the multifactorial process of aging, and to establish new biomarkers and/or therapeutic targets to counteract the underlying chronic inflammatory processes. One novel pathway that regulates peripheral and central immune responses is triggered by the cytokines pleiotrophin (PTN) and midkine (MK), which bind its receptor, Receptor Protein Tyrosine Phosphatase (RPTP) β/ζ, and inactivate its phosphatase activity. In this review, we compile a growing body of knowledge suggesting that PTN and MK modulate the immune response and/or inflammation in different pathologies characterized by peripheral inflammation associated with insulin resistance, such as aging, and in central disorders characterized by overt neuroinflammation, such as neurodegenerative diseases and endotoxemia. Evidence strongly suggests that regulation of the PTN and MK signaling pathways may provide new therapeutic opportunities particularly in those neurological disorders characterized by increased PTN and/or MK cerebral levels and neuroinflammation. Importantly, we discuss existing therapeutics, and others being developed, that modulate these signaling pathways, and their potential use in pathologies characterized by overt neuroinflammation

Local representations of change and conservation of the riparian forests along the São Francisco River (Northeast Brazil).

Investigations of local representations about the environment allow for the elucidation of historical landscape transformation and the elaboration of strategies for environmental conservation. Thus, this study aimed to answer the following questions. How does the local population represent the possible changes in riparian vegetation over time? What historical events were responsible for these possible changes? How does the local population represent concerns related to the use andmaintenance of riparian vegetation? This study was carried out with 87 informants from three communities: two rural ex-settlement communities and one quilombo in Northeastern Brazil. According to the informants, therewere changes in the riparian vegetation. Themain causes of these changes include the type of agriculture practiced in the region and the building of a large dam to provide water to the city of Sobradinho in the state of Bahia. However, there was no significant difference between the number of informants who said that the changes were for the worse and those who said that they were for the better. In addition, the respondents reported an increase in the abundance of exotic species and a decrease in the abundance of native species. Thus, the importance of including this group of people in the process of the forest restoration that will occur in the region is emphasized because they possess information about the past vegetation changes and their causes. They can also indicatewhich species should be prioritized for replanting according to their usage needs and they understand the importance of conserving riparian vegetation

Representações dos proprietários e funcionários de fazendas sobre as mudanças e conservação da vegetação ciliar às margens do rio São Francisco, Nordeste do Brasil.

No Brasil, foi marcante a ocupação de grupos humanos em áreas com potencial hídrico elevado para o desenvolvimento da agricultura irrigada. Neste contexto, inseri-se o rio São Francisco, que vem passando por constantes mudanças em relação à sua cobertura vegetal original. O presente estudo buscou responder as seguintes perguntas: Como fazendeiros e funcionários representam as possíveis mudanças da vegetação ciliar ao longo do tempo? Quais os eventos históricos responsáveis por essas possíveis mudanças? Como os fazendeiros e funcionários representam os aspectos relacionados às utilidades e à conservação da vegetação ciliar? Um total de 17 homens e oito mulheres, proprietários e funcionários de áreas próximas à vegetação ripária em cinco municípios dos estados da Bahia e Pernambuco, participaram da pesquisa. Entrevistas semiestruturadas e entrevista semiestruturada do tipo projetiva foram empregadas para investigar as representações sobre conservação da mata ciliar e mudanças locais da paisagem, bem como resgatar os eventos históricos que as influenciaram. Com o objetivo de registrar o conhecimento local sobre a diversidade de espécies úteis mais importantes foi utilizada a técnica de lista livre. Em relação às modificações da paisagem verificou-se que apenas um entrevistado afirmou não haver mudanças na vegetação ciliar, seis afirmaram que houve mudanças para pior e quatro para melhor. Quatro proprietários responderam que as mudanças na vegetação iniciaram há 10 anos, seis há mais de 30 anos, dois não sabiam e um não verificou mudanças. Entre os funcionários, cinco afirmaram que elas ocorreram há mais de 20 anos, quatro há mais de 10 anos e para quatro deles a vegetação não mudou. Observou-se que todos os informantes concordaram que a vegetação deve ser conservada, sendo que 64% destacaram que ela protege o rio e os outros 36% indicaram outras utilidades para a vegetação ciliar, tais como: atrair chuva, fazer sombra, usos medicinais e aumentar a quantidade de oxigênio. Sobre quem seriam os responsáveis pela conservação: 48% disseram que eram os próprios proprietários de terras, 48% afirmaram que era dever de todos conservar e 4% atribuíram a responsabilidade ao IBAMA. Eles também apontaram soluções para a conservação da vegetação ripária, como o reflorestamento (39%), não desmatar (17%), educação ambiental (13%) e cuidar bem (13%). Futuros projetos de restauração que podem vir a ocorrer nessa área devem levar em consideração essas diferentes representações, demandas e expectativas