Browsing Ciencias básicas by Title
Now showing items 1-20 of 2730
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1,1-Diphenyl-4-(thiophen-2-yl)but-3-yn-1-ol
(2018-11)The asymmetric unit of the title homopropargyl alcohol, C20H16OS, contains two independent molecules comprising a hydroxy group, a 3-(2-thiophenyl)- propargylic moiety and two aromatic rings linked to a central carbon atom. ... -
1,3-Bis{[(2,6-dimethylphenyl)sulfanyl]methyl}benzene
(2019)The structure of the title compound, C24H26S2, an example of a pincer ligand with an SCS-chelation motif, illustrates the steric effects of the methyl groups in the thiophenyl rings at the 2- and 6-positions, forcing a ... -
1-Nitro-4-(1-propyn-1-yl)benzene
(2019)The title compound, C9H7NO2, was prepared by alkynylation of 4-iodonitrobenzene with 1,3-dilithiopropyne in the presence of 1 equivalent of CuI and catalytic amounts of Pd(PPh3)2Cl2. The complete molecule is generated ... -
(1S,3R)-N-{(3S,10S,12S,13R,17R)-12-Hydroxy-17- [(R)-5-hydroxypentan-2-yl]-10,13-dimethylhexa- decahydro-1H-cyclopenta[a]phenanthren-3-yl}- adamantane-1-carboxamide 0.25-hydrate
(2022-10-12)The title compound, C 35H 57 NO 3 0.25H 2O, was synthesized from deoxycholic acid followed by a protection, a Mitsonobu substitution, a Staudinger reduction, formation of an amide and final reduction in the lateral chain. ... -
5,5-Diphenyl-cis-penta-2,4-dienoic acid
(2019)In the title compound, C17H14O2, the dihedral angle between the phenyl rings is 76.52 (7)°. In the crystal, pairwise O—H⋯O hydrogen bonds link the molecules into carboxylic acid inversion dimers. -
A basic model for the propagation of ideologies
(2022-11)Ideas and ideologies move the world and are involved in almost every aspect of human life and society. This paper presents a mathematical model for the propagation of two different ideologies in a group of people that could ... -
A BDDC algorithm with deluxe scaling for H(curl) in two dimensions with irregular subdomains
(2015)A bound is obtained for the condition number of a BDDC algorithm for problems posed in H(curl) in two dimensions, where the subdomains are only assumed to be uniform in the sense of Peter Jones. For the primal variable ... -
A biogeographical evaluation of high-elevation myxomycete assemblages in the northern Neotropics
(2011-08)This study represented an effort to apply some of the relatively well-known biogeographical and macroecological models to the observed structure of myxomycete assemblages, with emphasis on the northern Neotropical region. ... -
A brief survey of Higgs bundles
(2019-06)Considering a compact Riemann surface of genus greater or equal than two, a Higgs bundle is a pair composed of a holomorphic bundle over the Riemann surface, joint with an auxiliar vector field, so-called Higgs field. This ... -
A call-and-response system facilitates group cohesion among disc-winged bats
(2013)Acoustic signals are important in maintaining group cohesion, particularly in highly mobile species. For these signals to facilitate group cohesion, individuals must be able to recognize, and respond to, calls emitted by ... -
A carbonate platform associated with shallow cold methane seeps in Golfo Dulce, Pacific Costa Rica
(2015)Marine methane seeps are typically observed in cold, anoxic and organic-rich deep-sea environments, such as in the Black Sea, where methane emissions fuel the authigenic accretion of calcium carbonate structures via microbial ... -
A Chronoamperometric Screen Printed Carbon Biosensor Based on Alkaline Phosphatase Inhibition for W(VI) Determination in Water, Using 2-Phospho-l-Ascorbic Acid Trisodium Salt as a Substrate
(2015)This paper presents a chronoamperometric method to determine tungsten in water using screen-printed carbon electrodes modified with gold nanoparticles and cross linked alkaline phosphatase immobilized in the working ... -
A ClC Chloride Channel Homolog and Ornithine-Containing Membrane Lipids of Rhizobium tropici CIAT899 Are Involved in Symbiotic Efficiency and Acid Tolerance
(2005)Rhizobium tropici CIAT899 is highly tolerant to several environmental stresses and is a good competitor for nodule occupancy of common bean plants in acid soils. Random transposon mutagenesis was performed to identify novel ... -
A climate change projection for summer hydrologic conditions in a semiarid watershed of central Arizona
(2015-03-05)Potential climate change impacts on summer precipitation and subsequent hydrologic responses in the southwestern U.S. are poorly constrained at present due to a lack of studies accounting for high resolution processes. In ... -
A Climate Feature of the Tropical Americas: The Trade Wind Easterly Jet
(1998-06)Utilizando datos medios mensuales globales de los Reanálisis de NCEP/NCARP para el periodo 1982-1994 se documenta una característica de la circulación de las Américas tropicales no reportada hasta el momento en la literatura: ... -
A climatology of low level wind regimes over Central America using a weather type classification approach
(2015-04)Based on the potential of the weather types classification method to study synoptic features, this study proposes the application of such methodology for the identification of the main large scale patterns related with ... -
A Comparison of four Methods to Evaluate the Butterfly Abundance. Using a Tropical Community
(Journal of the Lepidopterists' Society 45(3), 1991, 241-243, 1991-03-18)In recent years. several transect methods to evaluate the abundance of butterflies have been proposed (Pollard, E. 1977, Biol. Conserv. 12:115—134; Feltwell, 3. 1982. Proc. Trans. Br. Entomol. Nat. Hist. Soc. 15:17—24). ... -
A comparison of Monstera deliciosa and M. tacanaensis, with comments on Monstera section Tornelia (Araceae)
(2020)Monstera deliciosa, one of the most commonly cultivated aroids, is a morphologically variable species and has traditionally been considered native to southern Mexico, Guatemala, Costa Rica and Panama. We demonstrate that ... -
A Constrained 3D Density Model of the Upper Crust from Gravity Data Interpretation for Central Costa Rica
(2010-01-05)The map of complete Bouguer anomaly of Costa Rica shows an elongated NW-SE trending gravity low in the central region. This gravity low coincides with the geographical region known as the Cordillera Volcánica Central. It ... -
A correction to the Lepanthes guatemalensis group (Orchidaceae: Pleurothallidinae) in Costa Rica, with a new species
(2021)The true Lepanthes edwardsii is first recorded for the flora of Costa Rica, described and illustrated on the basis of a Costa Rican voucher. The taxon previously recorded under that name is described as new to science as ...