992 research outputs found

    Wavelets: a powerful tool for studying rotation, activity, and pulsation in Kepler and CoRoT stellar light curves

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    Aims. The wavelet transform has been used as a powerful tool for treating several problems in astrophysics. In this work, we show that the time-frequency analysis of stellar light curves using the wavelet transform is a practical tool for identifying rotation, magnetic activity, and pulsation signatures. We present the wavelet spectral composition and multiscale variations of the time series for four classes of stars: targets dominated by magnetic activity, stars with transiting planets, those with binary transits, and pulsating stars. Methods. We applied the Morlet wavelet (6th order), which offers high time and frequency resolution. By applying the wavelet transform to the signal, we obtain the wavelet local and global power spectra. The first is interpreted as energy distribution of the signal in time-frequency space, and the second is obtained by time integration of the local map. Results. Since the wavelet transform is a useful mathematical tool for nonstationary signals, this technique applied to Kepler and CoRoT light curves allows us to clearly identify particular signatures for different phenomena. In particular, patterns were identified for the temporal evolution of the rotation period and other periodicity due to active regions affecting these light curves. In addition, a beat-pattern signature in the local wavelet map of pulsating stars over the entire time span was also detected.Comment: Accepted for publication on A&

    Dextran-Coated Magnetic Supports Modified with a Biomimetic Ligand for IgG Purification

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    The authors thank the financial support from Fundacao para a Ciencia e a Tecnologia through Grant PEst-C/EQB/LA0006/2011 and contracts no. PTDC/EBB-BIO/102163/2008, PTDC/EBB-BIO/098961/2008, PTDC/EBB-BIO/118317/2010, SFRH/BD/72650/2010 for V.L.D, and Santander Totta Bank - Universidade Nova de Lisboa for the Scientific Award 2009/2010. The authors are grateful to Dr. Abid Hussain and M. Telma Barroso (REQUIMTE, FCT-UNL, Portugal) for the preparation of the synthetic affinity ligands, to Lonza Biologics, U.K. (Dr. Richard Alldread), and the Animal Cell Technology Unit of ITQB-UNL/IBET (Dr. Paula M Alves and Dr. Ana Teixeira) for providing the cells and the culture bulks and to Mr. Filipe Cardoso and Prof. Paulo Freitas (INESC-MN, Lisbon, Portugal) for the help with the VSM measurements.Dextran-coated iron oxide magnetic particles modified with ligand 22/8, a protein A mimetic ligand, were prepared and assessed for IgG purification. Dextran was chosen as the agent to modify the surface of magnetic particles by presenting a negligible level of nonspecific adsorption. For the functionalization of the particles with the affinity ligand toward antibodies, three methods have been explored. The optimum coupling method yielded a theoretical maximum capacity for human IgG calculated as 568 ± 33 mg/g and a binding affinity constant of 7.7 × 10⁴ M⁻¹. Regeneration, recycle and reuse of particles was also highly successful for five cycles with minor loss of capacity. Moreover, this support presented specificity and effectiveness for IgG adsorption and elution at pH 11 directly from crude extracts with a final purity of 95% in the eluted fraction.proofpublishe

    Caracterização molecular para o estabelecimento de fingerprint de híbridos de bananeiras ornamentais utilizando marcadores ISSR e SSR.

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    A utilização de fruteiras ornamentais constitui-se em alternativa para o segmento da floricultura. A plasticidade das fruteiras variam desde o uso como plantas de parques, jardins, flores de corte, plantas de vaso, folhagens, até uso como minifrutos ornamentais. A Embrapa Mandioca e Fruticultura possui Bancos de Germoplasma (BAGs) de diferentes fruteiras, que recentemente começaram a ser explorados para diversas finalidades ornamentais. Dentre esses bancos, destaca-se o da Bananeira, com 341 acessos

    Fluid escape structures in the Gulf of Cadiz. Evidence of structural control from combined seismic reflection and sidescan sonar interpretation

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    The Gulf of Cadiz is situated in a tectonically complex and active region, close to a major plate boundary. The tectonic regime in the area is characterized by a combination of important strike-slip movement and compressional tectonics related to the Africa-Eurasia NW-directed convergence, responsible for the formation of the Gibraltar Arc. Extensive mud volcanism, pockmarks, mud diapirism and carbonate chimneys related to hydrocarbon rich fluid venting are observed throughout the area. There is an extensive coverage of seismic reflection profiles in the area that includes industry data, a few deep-multichannel lines (IAM, ARRIFANO and BIGSETS) and many single-channel lines (both Sparker and Airgun data). During the TTR-12 (July/2002) and the GAP (Nov-Dec/2003) cruises, several single and multi channel seismic lines were acquired in this area that complement the existing database collected during previous TTR Cruises. These lines have re-processed to enhance the deeper structure.A combined interpretation of the available side-scan sonar imaging obtained by the Naval Research Laboratory in 1992 and the available seismic lines (both single channel and multichannel) shows clear evidence of the structural control of the mud volcanism in the study area. In particular, it appears that some of the mud volcanoes are located at the intersection between NW-SE strike-slip faults and thrusts of variable orientation, reflecting the curvature of the Gibraltar Arc

    Profile of depressive symptoms in women in the perinatal and outside the perinatal period: similar or not?

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    Purposes To analyze which Beck Depression Inventory-II (BDI-II) and Postpartum Depression Screening Scores (PDSS) total and dimensional scores, as well as symptomatic answers proportions significantly differ between women in the perinatal period (pregnant/postpartum) without major depression, with major depression and women outside the perinatal period. Methods 572 pregnant women in the third trimester completed Beck Depression Inventory-II and Postpartum Depression Screening Scale and were assessed with the Diagnostic Interview for Genetic Studies. 417 of these were also assessed (with the same instruments) at three months postpartum. Ninety non-pregnant women or that did not have a child in the last year (mean age=29.42±7.159 years) also filled in the questionnaires. Results Non-depressed pregnant women showed lower scores than depressed pregnant women and higher scores than women outside the perinatal period in the BDI-II total score and in its Somatic-Anxiety dimension. Non-depressed postpartum women showed significantly higher scores than women outside the perinatal period only at Sleep/Eating Disturbances. Compared to women outside the perinatal period, pregnant women without depression presented higher scores only in the somatic items. Women with vs. without depression in the postpartum period did not significantly differ and both presented higher scores than women outside the perinatal period in the proportions of loss of energy and sleep changes. Limitations Women outside the perinatal period were not diagnosed for the presence of a depressive disorder, but their BDI-II mean score was similar to the figures reported worldwide regarding women in childbearing age. Conclusion In the perinatal period, most particularly at pregnancy, women experience significant somatic changes even if not clinically depressed. Cognitive-affective symptoms are more useful when assessing the presence of perinatal depression
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