1,102 research outputs found
Crystal structure of bis-[4-(1H-pyrrol-1-yl)phen-yl] ferrocene-1,1'-di-carboxyl-ate: a potential chemotherapeutic drug.
The title iron(II) complex, [Fe(C16H12NO2)2], crystallizes in the ortho-rhom-bic space group Pbca with the Fe(2+) cation positioned on an inversion center. The cyclo-penta-dienyl (Cp) rings adopt an anti conformation in contrast with other substituted ferrocenes in which the Cp rings appear in a nearly eclipsed conformation. The Cp and the aromatic rings are positioned out of the plane, with a twist angle of 70.20 (12)°, and the C(Cp)-C(CO) bond length is shorter than a typical C-C single bond, which suggests a partial double-bond character and delocalization with the Cp π system. The structure of the complex is compared to other functionalized ferrocenes synthesized in our laboratory
Sedimentary heterogeneity and petrophysical characterization of Barremian tsunami and barrier island/inlet deposits: The Aliaga outcrop as a reservoir analogue (Galve sub-basin, eastern Spain)
The present study examined two sandstone deposits in the Aliaga outcrop as a reservoir analogue over a distance of 200-m-long and attempted to establish a correlation between sand facies and the petrophysical properties of the sandstones in order to investigate the reservoir heterogeneity. The Aliaga reservoir analogue represents the upper part of Camarillas Fm., deposited during the Barremian synrift phase of the Galve sub-basin (Iberian Basin, Spain). It is characterized by a transitional sedimentary interval from sandy-dominant deposits to carbonate-dominant deposits, which were deposited under the same palaeoenvironmental conditions (in relation to systems of back-barrier sedimentation).
The description of the Aliaga outcrop provided here consists of lithological descriptions of two sandstone deposits: a tsunami and a barrier island/inlet, at both mesoscopic (decimetres to tens of metres) and microscopic scales (millimetres to centimetres). Both deposits recognized at the basin scale were described in terms of sand grain size, sand sorting and cementation; further cores were drilled along outcrop to collect samples for porosity and permeability measurements.
Both sandstone reservoirs are the result of different sedimentary processes that determined facies characteristics, as the different petrophysical properties observed in these deposits. Consequently, the sedimentary process controls the heterogeneity of the sandstones facies and thus, the sand heterogeneity controls the distribution of the petrophysical properties. The classification of sand facies in terms of sand sorting seems to be more appropriate for describing sand heterogeneity; accordingly, petrophysical parameters in both deposits were also influenced by sand sorting.
The sand facies and petrophysics heterogeneity of the described deposits can be hierarchically ordered. First-order heterogeneity is related to the basin scale, second-order heterogeneity is related to genesis and the conditions of sediment deposition, and third-order heterogeneity is related to synsedimentary faults and/or post-sedimentation events.This research is a contribution to the project: Análisis de Cuencas Sedimentarias Continentales, of the Gobierno de Aragón, the Análisis de Cuencas Sedimentarias Group of the UCM-CAM, and the projects CGL2011-23717 (Ministerio de Ciencia e Innovación of the Spanish Government and FEDER) and UZ2015-CIE-10 (University of Zaragoza). Additional financial support was provided by a Cnpq (Conselho Nacional de Pesquisa e Desenvolvimento Tecnologico, Brasil) Research Grant (200147/2011-0) and an IAS Schema 1st session 2014 Postgraduate Grant to F. Veloso.Peer reviewe
The age and abundance structure of the stellar populations in the central sub-kpc of the Milky Way
The four main findings about the age and abundance structure of the Milky Way
bulge based on microlensed dwarf and subgiant stars are: (1) a wide metallicity
distribution with distinct peaks at [Fe/H]=-1.09, -0.63, -0.20, +0.12, +0.41;
(2) a high fraction of intermediate-age to young stars where at [Fe/H]>0 more
than 35 % are younger than 8 Gyr, (3) several episodes of significant star
formation in the bulge 3, 6, 8, and 11 Gyr ago; (4) the `knee' in the
alpha-element abundance trends of the sub-solar metallicity bulge appears to be
located at a slightly higher [Fe/H] (about 0.05 to 0.1 dex) than in the local
thick disk.Comment: 4 pages, contributed talk at the IAU Symposium 334 "Rediscovering our
Galaxy" in Potsdam, July 10-14, 201
A Reflection on Growth Mindset and Meritocracy
As mathematicians working in higher education we reflect on meritocracy and growth mindset with a focus on the relationship between the two. We also note the subtle differences between growth mindset and grit. Our reflection ends with suggestions for how to move forward in the math classroom and throughout the collegiate level
COLECTA Y CONSERVACIÓN in vitro Y ex situ DE RECURSOS FITOGENÉTICOS DE Carica papaya L.
Fruit buds from Creole papaya (Carica papaya L.) were collected in the center and south of the state of Baja California Sur, MĂ©xico, in the localities of El Pescadero, Ejido en ComondĂş Ley Federal de Aguas #2, La Paz, La PurĂsima, La Ribera, San Bartolo, San Javier, San Miguel de ComondĂş and Todos Santos, with the aim of conservation and multiplication. The buds were multiplied under aseptic conditions, in glass containers with 20 ml of Murashige-Skoog (MS) (1962) medium, with 3 % sucrose and 0.8 % agar for its in vitro cultivation. Treatments were used for the in vitro propagation and rooting of the buds; the results obtained show that 2 mg L-1 of naphthalene acetic acid increase the production of buds. The indole-butyric acid at a concentration of 3 uM generates the rooting of the buds, which once established develop quickly. Part of this material was transferred to greenhouse conditions for its acclimation and later planting into the field. Therefore, germplasm from Creole papaya seeds and plants is conserved in vitro and ex situ.Se recolectaron frutos brotes de papaya (Carica papaya L.) criolla en el centro y sur de Estado de Baja California Sur, MĂ©xico, en las localidades de El Pescadero, Ejido en ComondĂş Ley Federal de Aguas #2, La Paz, La PurĂsima, La Ribera, San Bartolo, San Javier, San Miguel de ComondĂş y Todos Santos, con el fin de conservaciĂłn y multiplicaciĂłn. Se multiplicaron los brotes en condiciones asĂ©pticas, en frascos de vidrio conteniendo 20 ml de medio Murashige-Skoog (MS) (1962) con 3% de sacarosa y 0.8% de agar para su cultivo in vitro. Se realizaron tratamientos para la propagaciĂłn y enraizamiento in vitro de los brotes, los resultados obtenidos muestran que 2 mg L-1 de ácido naftalen acĂ©tico incrementa la producciĂłn de brotes. El ácido indol butĂrico a concentraciones de 3 uM genera el enraizamiento de los brotes, los cuales una vez establecidos, se desarrollan rápidamente. Parte de este material fue transferido a condiciones de invernadero para su aclimataciĂłn y posterior siembra a campo. Por lo que actualmente se conserva germoplasma de semillas y plantas de papaya criolla in vitro y ex situ
The Solar Twin Planet Search. V. Close-in, low-mass planet candidates and evidence of planet accretion in the solar twin HIP 68468
[Methods]. We obtained high-precision radial velocities with HARPS on the ESO
3.6 m telescope and determined precise stellar elemental abundances (~0.01 dex)
using MIKE spectra on the Magellan 6.5m telescope. [Results]. Our data indicate
the presence of a planet with a minimum mass of 26 Earth masses around the
solar twin HIP 68468. The planet is a super-Neptune, but unlike the distant
Neptune in our solar system (30 AU), HIP 68468c is close-in, with a semi-major
axis of 0.66 AU, similar to that of Venus. The data also suggest the presence
of a super-Earth with a minimum mass of 2.9 Earth masses at 0.03 AU; if the
planet is confirmed, it will be the fifth least massive radial velocity planet
discovery to date and the first super-Earth around a solar twin. Both
isochrones (5.9 Gyr) and the abundance ratio [Y/Mg] (6.4 Gyr) indicate an age
of about 6 billion years. The star is enhanced in refractory elements when
compared to the Sun, and the refractory enrichment is even stronger after
corrections for Galactic chemical evolution. We determined a NLTE Li abundance
of 1.52 dex, which is four times higher than what would be expected for the age
of HIP 68468. The older age is also supported by the low log(R'HK) (-5.05) and
low jitter. Engulfment of a rocky planet of 6 Earth masses can explain the
enhancement in both lithium and the refractory elements. [Conclusions]. The
super-Neptune planet candidate is too massive for in situ formation, and
therefore its current location is most likely the result of planet migration
that could also have driven other planets towards its host star, enhancing thus
the abundance of lithium and refractory elements in HIP 68468. The intriguing
evidence of planet accretion warrants further observations to verify the
existence of the planets that are indicated by our data and to better constrain
the nature of the planetary system around this unique star.Comment: A&A, in pres
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