The variability behavior of CoRoT M-giant Stars

For 6 years the Convection, Rotation, and Planetary Transits (CoRoT) space mission has acquired photometric data from more than one hundred thousand point sources towards and directly opposite from the inner and outer regions of the Galaxy. The high temporal resolution of the CoRoT data combined with the wide time span of the observations has enabled the study of short and long time variations in unprecedented detail. From the initial sample of 2534 stars classified as M-giants in the CoRoT databasis, we selected 1428 targets that exhibit well defined variability, using visual inspection. The variability period and amplitude of C1 stars (stars having Teff < 4200 K) were computed using Lomb-Scargle and harmonic fit methods. The trends found in the V-I vs J-K color-color diagram are in agreement with standard empirical calibrations for M-giants. The sources located towards the inner regions of the Galaxy are distributed throughout the diagram while the majority of the stars towards the outer regions of the Galaxy are spread between the calibrations of M-giants and the predicted position for Carbon stars. The stars classified as supergiants follow a different sequence from the one found for giant stars. We also performed a KS test of the period and amplitude of stars towards the inner and outer regions of the Galaxy. We obtained a low probability that the two samples come from the same parent distribution. The observed behavior of the period-amplitude and period-Teff diagrams are, in general, in agreement with those found for Kepler sources and ground based photometry, with pulsation being the dominant cause responsible for the observed modulation. We also conclude that short-time variations on M-Giant stars do not exist orare very rare and the few cases we found are possibly related to biases or background stars.Comment: 11 pages, 6 figure

Near-infrared luminescent and magnetic cyano-bridged coordination polymers Nd(phen)(n)(DMF)(m)[M(CN)(8)] (M = Mo, W)

New cyano-bridged coordination polymers [Nd(phen)(2)(DMF)(2)(H(2)O)Mo(CN)(8)] center dot 2H(2)O (1) and [Nd(phen)(DMF)(5)M(CN)(8)] center dot xH(2)O [M = Mo (2), W (3); phen = 1,10-phenanthroline] have one-dimensional structures with variable number of phenanthroline ligands. Compounds exhibit photoluminescence in the near-infrared region and ferromagnetic Nd(3+)-M(5+) interactions

Multifunctionality of the [C2mim][Ln(fod)4] series (Ln = Nd-Tm except Pm):magnetic, luminescent and thermochemical studies

A series of nine tetrakis lanthanide β-diketonate complexes of the type [C2mim][Ln(fod)4] (C2mim = 1-ethyl-3-methylimidazolium, fod = 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate) were prepared, with yields above 80%, and their thermochemical, photophysical and magnetic susceptibilities were evaluated. Thermochemical studies presented a rare and reversible conversion between two solid phases (polymorphism), characteristic of the [Ln(fod)4]− anion. Photophysical and magnetic studies revealed that Dy and Er presented the multifunctionality of being simultaneously SMMs and visible (Dy) or near infra-red (Er) emitters. The Nd, Ho and Tm analogues present characteristic emission bands in the NIR region (800–1200 nm), while Sm, Eu, Tb and Dy present emissions in the visible range. Magnetic susceptibility of Tb, Dy, Ho, Er and Tm salts were measured in the temperature range of 2–300 K, showing paramagnetic behaviour, although with different regimes, with AC susceptibility measurements, at different frequencies in the range of 10–10 000 Hz, providing evidence of slow magnetic relaxation processes for Gd, Dy and Er analogues with SMM behavior.publishe

Aplicação de um método de interpolação físico-estatístico para a temperatura e pressão atmosférica sobre uma região de topográfica variável.

No presente trabalho os dados observados durante a campanha de campo de observações meteorológicas, associado à base de dados topográficos 3s-SRTM, foram utilizados para extrapolar as observações de temperatura do ar e pressão atmosférica para a região do Parque Nacional de Itatiaia (PNI). Para interpolação dos dados de temperatura e pressão sobre a área do PNI foram utilizados princípios físicos e estatísticos de interpolação. O método de interpolação pelo quadrado da distância utilizado juntamente com as outras equações físicas para estimar a temperatura do ar e a pressão atmosférica, sobre região do PNI, apresentou valores consistentes com os observados. Logo, o método pode ser empregado para a geração de mapas destas variáveis meteorológicas para regiões onde há baixa densidade de estações meteorológicas, em particular onde há acentuada variação topográfica

Influência do fósforo e de diferentes regimes de corte sobre a digestibilidade in vitro do capim-de-raiz (Chloris orthonoton, Doell).

O presente trabalho objetivou avaliar a digestibilidade do capim-de-raiz submetido a diferentes doses de fósforo, frequências e intensidades de corte

Application of PEG400 in the one-pot synthesis of 7-[4-alkyl- or (hetero) aryl-1H-1,2,3-triazol-1-yl]thieno[3,2-b]pyridines via SNAr and Cu(I)- Catalyzed Azide-Alkyne Cycloaddition and preliminary evaluation of their anti-tumour activity

Several novel 7-[4-alkyl- or (hetero)aryl-1H-1,2,3-triazol-1-yl]thieno[3,2-b]pyridines were prepared in good to high yields, using the environmentally friendly solvent PEG400 in a one-pot procedure from 7- chlorothieno[3,2-b]pyridine to form the corresponding azide via SNAr with NaN3, followed by Cu(I)-catalyzed Azide-Alkyne Cycloaddition (CuAAC) using different types of alkynes. This one-pot reaction in PEG400 starting from a halogenated heteroaromatic system is reported for the first time and demonstrated a wide scope of application for alkynes. Preliminary anti-tumour activity on human tumour cell lines using the prepared 1,4-di(hetero)aryl-1,2,3-triazoles was evaluated, together with their toxicity in non-tumour cells. Among the tested compounds the most promising one was a 2-ethynylpyridine derivative.Fundação para a Ciência e Tecnologia (FCT)–Portugal financially supports CQUM (UID/QUI/686/2019), CIMO-IPBragança (UID/ AGR/690/2019), the research project PTDC/QUI-QFI/28020/2017 (POCI-01-0145-FEDER-028020) also financed by European Regional Development Fund (ERDF), COMPETE2020 and Portugal2020, the PTNMR network also supported by Portugal2020 and the PhD grant of J.M.R. (SFRH/BD/115844/2016) also financed by ESF (European Social Fund) and HCOP (Human Capital Operational Programme).info:eu-repo/semantics/publishedVersio

Latin American platform comparative critical analysis. Learning from the KASSA platforms' reports.

1 CD-ROM. Projeto DG-Research - Contract nº GOCE-CT-2004-505582

Synthesis, characterisation and luminescent properties of lanthanide-organic polymers with picolinic and glutaric acids

Three new lanthanide(III) complexes (Ln = Sm, Tb and Eu) of picolinic and glutaric acid were prepared and characterised. The crystal structure of the complex [Sm(glu)(pic)- (H2O)2] (where Hpic and H2glu stand for picolinic and glutaric acid, respectively) was determined by single-crystal Xray diffraction. All the Ln complexes were characterised by elemental analysis, infrared spectroscopy, X-ray powder diffraction and thermoanalytical measurements. The combined Introduction The design of functional units from the molecular scale to macroscopic assemblies has emerged as a new paradigm in materials synthesis resulting in an interplay between conventional molecular chemistry and conventional solid-state science. This has been particularly clear in the development of functional materials using coordination compounds such as in the field of semiconductors technology, supramolecular machinery, microporous and hybrid materials and catalysis.[ 1] In some cases, the development of these functional materials is based on the chemistry of well-known coordination compounds as illustrated by the assembly of inorganic- organic extended lattices[2] and in the thermolysis of metal thiolato compounds to produce thin films or nanoparticles.[ 3] Metals coordinated to aromatic ambidentate ligands form a class of compounds with a wide variety of coordination modes which has long attracted the attention of chemists.[ 4] Griffith and co-workers extended this type of chemistry to the second row transition metals and, in particular, [a] Department of Chemistry, University of Aveiro, CICECO, 3810-193 Aveiro, Portugal Fax: +351-234-370-084 E-mail: [email protected] [b] Department of Physics, University of Aveiro, CICECO, 3810-193 Aveiro, Portugal [c] Department of Chemistry, University of Cambridge, Lensfield Road, CB2 1EW Cambridge, United Kingdom Supporting information for this article is available on the WWW under http://www.eurjic.org or from the author. © 2007 Wiley-VCH Verlag 4238 GmbH & Co. KGaA, Weinheim Eur. J. Inorg. Chem. 2007, 4238–4246 data show that these Ln complexes are isostructural. The effect of both organic ligands on the photoluminescent behaviour of the Sm3+, Eu3+ and Tb3+ complexes is discussed and we anticipate the possibility of controlling the photoluminescence of picolinic-containing lanthanide compounds by systematically varying the length of the bridging ligand.FCT - POCI/QUI/58377/2004Grant - SFRH/BD/17968/2004Grant - SFRH/BPD/14954/ 200