1,400 research outputs found

    1,5-Bis(2,5-dimethyl-1H-pyrrol-1-yl)naphthalene

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    In the title compound, C22H22N2, the asymmetric unit contains one half-mol­ecule. A crystallographic inversion centre is located at the mid-point of the bond common to both rings, in the central naphthalene unit. Quantum-mechanical ab initio calculations on the isolated mol­ecule showed that the minimum energy configuration occurs when the naphthalene ring system and the pyrrolyl groups deviate only slightly from perpendicularity. In the crystal, due to the effects of crystal packing, the mol­ecule deviates by approximately 4° from the a priori expected ideal value of 90° [C—C—N—C torsion angle = 86.11 (15)°]

    Análise sensorial e microbiológica da carne ovina submetida a diferentes formas de conservação no pós-abate.

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    Foram utilizados seis cordeiros machos da raça Santa Inês, castrados, com idade média de quatro meses, que foram abatidos com peso entre 30-35 kg com o objetivo de avaliar o e feito de três tipos de acondicionamento da carne ovina (natural, resfriada e congelada) na qualidade sensorial e microbiológica da carne. Para a análise sensorial foi separado e preparado o músculo Longissimus dorsi para um painel de provadores que avaliaram a carne quanto ao aroma, sabor, maciez, suculência, mastigabilidade e aparência geral. O mesmo músculo foi utilizado para a análise microbiológica onde se determinaram coliformes totais e fecais, bolores e leveduras. A carne in natura foi mais macia e de melhor mastigabilidade (p<0,05) em relação à resfriada e congelada. Observou-se também nas carcaças não resfriadas maior incidência de bolores e leveduras e presença de coliformes fecais. Apesar da carne in natura ter apresentado maior maciez, o crescimento microbiano foi maior neste tipo de conservação pós abate, o que pode comprometer a saúde humana

    THE VLT LEGA-C spectroscopic survey:the physics of galaxies at a lookback time of 7 Gyr

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    The Large Early Galaxy Census (LEGA-C) is a Public Spectroscopic Survey of ~3200 K-band selected galaxies at redshifts z = 0.6 − 1.0 with stellar masses M>1010M{M}_{*}\gt {10}^{10}\quad {M}_{\odot }, conducted with VIMOS on ESO's Very Large Telescope. The survey is embedded in the COSMOS field (R.A. = 10h00; decl.  =  +2  deg\mathrm{decl}.\;=\;+2\;\mathrm{deg}). The 20 hr long integrations produce high-signal-to-noise ratio continuum spectra that reveal ages, metallicities and velocity dispersions of the stellar populations. LEGA-C's unique combination of sample size and depth will enable us for the first time to map the stellar content at large lookback time, across galaxies of different types and star formation activity. Observations started in 2014 December and are planned to be completed by mid 2018, with early data releases of the spectra and value-added products. In this paper we present the science case, the observing strategy, an overview of the data reduction process and data products, and a first look at the relationship between galaxy structure and spectral properties, as it existed 7 Gyr ago

    Mutual and self-diffusion of charged porphyrines in aqueous solutions

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    a b s t r a c t We have investigated the diffusion properties for an ionic porphyrin in water. Specifically, for the {tetra-sodium tetraphenylporphyrintetrasulfonate (Na 4 TPPS) + water} binary system, the self-diffusion coefficients of TPPS 4À and Na + , and the mutual diffusion coefficients were experimentally determined as a function of Na 4 TPPS concentration from (0 to 4) Á 10 À3 mol Á dm À3 at T = 298.15 K. Absorption spectra for this system were obtained over the same concentration range. Molecular mechanics were used to compute size and shape of the TPPS 4À porphyrin. We have found that, at low solute concentrations ), the mutual diffusion coefficient sharply decreases as the concentration increases. This can be related to both the ionic nature of the porphyrin and complex associative processes in solution. Our experimental results are discussed on the basis of the Nernst equation, Onsager-Fuoss theory and porphyrin metal ion association. In addition, self-diffusion of TPPS 4À was used, together with the Stokes-Einstein equation, to determine the equivalent hydrodynamic radius of TPPS 4À . By approximating this porphyrin to a disk, we have estimated structural parameters of TPPS 4À . These were found to be in good agreement with those obtained using molecular mechanics. Our work shows how the self-diffusion coefficient of an ionic porphyrin in water is substantially different from the corresponding mutual-diffusion coefficient in both magnitude and concentration dependence. This aspect should be taken into account when diffusion-based transport is modelled for in vitro and in vivo applications of pharmaceutical relevance

    The MHD nature of ionospheric wave packets excited by the solar terminator

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    We obtained the first experimental evidence for the magnetohydrodynamic (MHD) nature of ionospheric medium-scale travelling wave packets (MSTWP). We used data on total electron content (TEC) measurements obtained at the dense Japanese network GPS/GEONET (1220 stations) in 2008-2009. We found that the diurnal, seasonal and spectral MSTWP characteristics are specified by the solar terminator (ST) dynamics. MSTWPs are the chains of narrow-band TEC oscillations with single packet's duration of about 1-2 hours and oscillation periods of 10-20 minutes. Their total duration is about 4--6 hours. The MSTWP spatial structure is characterized by a high degree of anisotropy and coherence at the distance of more than 10 wavelengths. The MSTWP direction of travelling is characterized by a high directivity regardless of seasons. Occurrence rate of daytime MSTWPs is high in winter and during equinoxes. Occurrence rate of nighttime MSTIDs has its peak in summer. These features are consistent with previous MS travelling ionosphere disturbance (TID) statistics obtained from 630-nm airglow imaging observations in Japan. In winter, MSTWPs in the northern hemisphere are observed 3-4 hours after the morning ST passage. In summer, MSTWPs are detected 1.5-2 hours before the evening ST occurrence at the point of observations, at the moment of the evening ST passage in the magneto-conjugate point. Both the high Q-factor of oscillatory system and synchronization of MSTWP occurrence with the solar terminator passage at the point of observations and in the magneto-conjugate area testify the MHD nature of ST-excited MSTWP generation. The obtained results are the first experimental evidence for the hypothesis of the ST-generated ion sound waves.Comment: 12 pages, 3 figure
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