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

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&

High-pressure study of the non-Fermi liquid material U_2Pt_2In

The effect of hydrostatic pressure (p<= 1.8 GPa) on the non-Fermi liquid state of U_2Pt_2In is investigated by electrical resistivity measurements in the temperature interval 0.3-300 K. The experiments were carried out on single-crystals with the current along (I||c) and perpendicular (I||a) to the tetragonal axis. The pressure effect is strongly current-direction dependent. For I||a we observe a rapid recovery of the Fermi-liquid T^2-term with pressure. The low-temperature resistivity can be analysed satisfactorily within the magnetotransport theory of Rosch, which provides strong evidence for the location of U_2Pt_2In at an antiferromagnetic quantum critical point. For I||c the resistivity increases under pressure, indicating the enhancement of an additional scattering mechanism. In addition, we have measured the pressure dependence of the antiferromagnetic ordering temperature (T_N= 37.6 K) of the related compound U_2Pd_2In. A simple Doniach-type diagram for U_2Pt_2In and U_2Pd_2In under pressure is presented.Comment: 21 pages (including 5 figures); pdf forma

Notes on the taxonomy, iconography, and ecology of <i>Aloe pluridens</i> Haw. (Asphodelaceae: Alooideae), an endemic species from southeastern South Africa

The history of the discovery of Aloe pluridens Haw (Asphodelaceae: Alooideae) by the Kew collector James Bowie in 1822–23 in the Eastern Cape Province of South Africa and its subsequent description in 1824 is discussed. The surprising dearth of published illustrations of this long-known species is emphasised and the first known photograph dating from only 1900 is reproduced. It is also shown that a painting at Kew by George Bond that dates from 1829 does not qualify as having been associated with the species by the author of the name, Adrian Hardy Haworth and cannot supersede the specimen on which the name A. pluridens was previously effectively neo-typified. The name A. pluridens Haw. var. beckeri Schönland is lectotypified and it is shown that the name Aloe atherstonei does not have a type as it was previously typified on an apparently non-existent specimen. Additionally the species is illustrated both in habitat and in cultivation. Observations on the ecology and cultivation of the species are also included

Magnetic quantum critical point and superconductivity in UPt3 doped with Pd

Transverse-field muon spin relaxation measurements have been carried out on the heavy-fermion superconductor UPt3 doped with small amounts of Pd. We find that the critical Pd concentration for the emergence of the large-moment antiferromagnetic phase is ~0.6 at.%Pd. At the same Pd content, superconductivity is completely suppressed. The existence of a magnetic quantum critical point in the phase diagram, which coincides with the critical point for superconductivity, provides evidence for ferromagnetic spin-fluctuation mediated odd-parity superconductivity, which competes with antiferromagnetic order.Comment: 4 pages (includes 3 figures); postscript fil

Magnetic quantum critical point and superconductivity in UPt3 doped with Pd

Transverse-field muon spin relaxation measurements have been carried out on the heavy-fermion superconductor UPt3 doped with small amounts of Pd. We find that the critical Pd concentration for the emergence of the large-moment antiferromagnetic phase is ~0.6 at.%Pd. At the same Pd content, superconductivity is completely suppressed. The existence of a magnetic quantum critical point in the phase diagram, which coincides with the critical point for superconductivity, provides evidence for ferromagnetic spin-fluctuation mediated odd-parity superconductivity, which competes with antiferromagnetic order.Comment: 4 pages (includes 3 figures); postscript fil

Proteção dos frutos do abacaxi ao ataque de Strymon megarus (Godt., 1824) utilizando óleo essencial rico em dilapiol.

O óleo essencial de Piper aduncum L. apresenta potencial de uso inseticida relatado em vários trabalhos realizados em condições de laboratório. No estado do Acre, esta piperácea é abundante e a produção do óleo em escala comercial apresenta viabilidade econômica. O efeito inseticida desse óleo essencial, rico em dilapiol, foi avaliado ao nível de campo, no controle da broca-do-abacaxi, Strymon megarus (Godt., 1824), por meio de um experimento em blocos casualizados com 7 repetições dos seguintes tratamentos: a) óleo de P. aduncum (75,3% de dilapiol) a 1,5 L/ha; b) inseticida comercial a base de deltametrina a 300 mL/ha e c) testemunha (pulverização com água). A cultivar regional utilizada foi a Rio Branco plantada em fileiras duplas no espaçamento de 1,20m x 0,50 m x 0,50m. Adotou-se como parcela experimental 8 fileiras de 10 m de comprimento cada, correspondendo a 160 plantas (frutos). A uniformização do florescimento foi realizada por indução com carbureto de cálcio. As pulverizações dos tratamentos e a contagem dos frutos com sintomas de ataque da broca foram realizadas quinzenalmente a partir do florescimento, totalizando sete avaliações. A comparação do número médio de frutos atacados foi realizada pelo teste de Tukey a 5% de probabilidade. Não houve diferença significativa dentro de cada época de avaliação, entre o número de frutos atacados por S. megarus em plantas tratadas com o óleo de P. aduncum e o inseticida a base de deltametrina, que mantiveram, respectivamente, o nível de danos entre 13% e 6% do total de frutos avaliados. Tais valores diferiram significativamente da testemunhada (60% de frutos danificados). Desta forma, pode-se considerar promissora a utilização do óleo essencial de P. aduncum na proteção de frutos de abacaxi contra a broca dos frutos, S. megarus.Projeto 03.10.01.026.00.0

Fabrication of a Horizontal and a Vertical Large Surface Area Nanogap Electrochemical Sensor

Nanogap sensors have a wide range of applications as they can provide accurate direct detection of biomolecules through impedimetric or amperometric signals. Signal response from nanogap sensors is dependent on both the electrode spacing and surface area. However, creating large surface area nanogap sensors presents several challenges during fabrication. We show two different approaches to achieve both horizontal and vertical coplanar nanogap geometries. In the first method we use electron-beam lithography (EBL) to pattern an 11 mm long serpentine nanogap (215 nm) between two electrodes. For the second method we use inductively-coupled plasma (ICP) reactive ion etching (RIE) to create a channel in a silicon substrate, optically pattern a buried 1.0 mm 1.5 mm electrode before anodically bonding a second identical electrode, patterned on glass, directly above. The devices have a wide range of applicability in different sensing techniques with the large area nanogaps presenting advantages over other devices of the same family. As a case study we explore the detection of peptide nucleic acid (PNA)&amp;#x100000;DNA binding events using dielectric spectroscopy with the horizontal coplanar device

Potencialidades da pimenta-de-macaco (Piper aduncum L.): características gerais e resultados de pesquisa.

A diversidade da flora brasileira, em especial a da Região Amazônica, apresenta um imenso potencial para a produção de compostos secundários de plantas, que têm sido demandados continuamente pela indústria nas últimas décadas, devido ao incremento da utilização de produtos naturais na agropecuária. Estima-se que existam 500 mil espécies de plantas no mundo, sendo .16% delas encontradas na florésta amazônica. No entanto, a pesquisa de substâncias ativas derivadas de plantas no Brasil ainda é muito incipiente. Mesmo considerando os incrementos significativos da pesquisa nas últimas duas décadas, há, evidentemente, uma grande lacuna de conhecimento da nossa flora a ser preenchida. A partir da década de 90 a Embrapa Acre vem intensificando atividades de pesquisa no sentido de viabilizar a utilização de recursos não-madeireiros das florestas do Acre. Destacam-se dentre eles, produtos promissores oriundos de piperáceas, como o óleo essencial rico em safrol, produzido a partir da biomassa da Piper hispidinervum e, mais recentemente, o óleo essencial de P. aduncum com altos teores de dilapiol. P. aduncum é uma espécie de planta que vem apresentando um crescente interesse, principalmente quanto à extração em escala industrial do seu óleo essencial. A elaboração deste documento tem como finalidade contribuir para o conhecimento da potencialidade do emprego dessa planta na elaboração de produtos para o controle de pragas de interesse agropecuário e utilização na medicina humana.bitstream/item/117348/1/14457.pd

Current Results of the EC-sponsored Catchment Modelling (CatchMod) Cluster

To support the Water Framework Directive implementation, much research has been commissioned at both national and European levels. CatchMod is a cluster of these projects, which is focusing on the development of computational catchment models and related tools. This paper presents an overview of the results of the CatchMod cluster to dat