Ciencias básicas
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Biología [1436]
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Meteorología [387]
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Química [291]
Recent Submissions
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Three new bird species for Cocos Island, Costa Rica, and additional observations of other vagrants
(2019)En esta nota presentamos tres nuevos registros de especies en la isla del Coco, Costa Rica: Aguja Lomiblanca Limosa haemastica, Mosquerito de Traill Empidonax traillii / Mosquerito de Charral E. alnorum y Reinita de Costados ... -
Genetic structure in neotropical birds with different tolerance to urbanization
(2022)Gene flow in birds can be affected by urbanization depending on natural history traits and adaptability to habitat change. Contrasting results can be expected when comparing species with opposite resilience to urbanization. ... -
The role of learning, acoustic similarity and phylogenetic relatedness in the recognition of distress calls in birds
(2021-05)Many groups of vertebrates produce distress calls when attacked by predators as a last attempt to survive. However, few studies investigate whether recognition of distress calls involves learning or acoustic similarity to ... -
Range expansion and noteworthy records of Costa Rican birds (Aves)
(2018-01-19)We present new distribution information for 19 species of Costa Rican birds. Thirteen species show changes in altitudinal distribution, 9 are recorded at higher elevations such as Egretta rufescens (Gmelin, 1789), Heliomaster ... -
Megaherbivore exclusion led to more complex seagrass canopies and increased biomass and sediment Corg pools in a tropical meadow
(2022)In some regions of the Caribbean Sea, seagrasses have been negatively affected by sea turtle overgrazing. Seagrass canopy complexity has declined at a long-term monitoring site in Costa Rica. We deployed megaherbivore ... -
Synthesis and preliminary determination of antibacterial activity of some 1,3-enynes
(2019)The synthesis of five 1,3-enynes was performed and its activity against Gram-positive and Gram-negative bacteria was determined. -
Antimicrobial activity of sodium carboxylates against arcobacter sp. y campylobacter Sp.
(2019)Arcobacter and Campylobacter genres are pathogenic microorganisms associated with gastrointestinal diseases and their main transmission route is through food and water. Both genres have been strongly associated to poultry, ... -
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. -
N-[3-(Prop-1-yn-1-yl)phenyl]benzenesulfonamide
(2019)In the title sulfanilamide derivative, C15H13NO2S, which shows significant activity against Staphylococcus aureus and Escherichia coli, the dihedral angle between the planes of the aromatic rings is 62.15 (19)° and the ... -
A Facile Method for the Titration of Organolithium Reagents using Naphtylamine or Naphtylmethylamine as Indicators
(2019)A simple method for the titration of alkyllithiums with sec-butanol, using naphtylamine or naphtylmethylamine as color indicator, is reported. Both amines gave sharp-end points, easily determined by color changes from ... -
One-Pot Conversion of Aldehydes and Ketones into 1-Substituted and 1,4-Disubstituted 1,3-Enynes
(2018)Sequential treatment of 2,3-dichloropropene with magnesium and n-BuLi generates the operational equivalent of 1,3-dilithiopropyne, which upon treatment with aldehydes or ketones, produces the corresponding alkoxy lithium ... -
Synthesis and Biological Activity of New Antifungal Compounds: A Preliminary Study
(2018)In the present study, we synthesized three 1,3-enynes from their corresponding aldehydes. They exhibited antifungal activity, which was evaluated against Trichophyton rubrum, the most common dermatophyte responsible for ... -
Description of the nest and eggs of the green thorntail (discosura conversii)
(2016-06-15)The breeding biology of the genus Discosura (Trochilidae) is poorly known. Here, we describe in detail the nest and eggs of the Green Thorntail (D. conversii). We analyze two nests; one was collected with two eggs at Limón ... -
A facile method for the preparation of bishomopropargylic alcohols from acyl chlorides
(2014)Controlled dilithiation of propargyl bromide with two equivalents of n-butyllithium, in the presence of TMEDA, produces the operational equivalent of the dianion 1,3-dilithiopropyne. The latter reacts efficiently with ... -
Nueva síntesis de la feromona sexual de la polilla del repollo Plutella Xylostella
(2007)El compuesto (Z)-11-hexadecenal, feromona sexual de la polilla Plutella xylostella, fue preparado mediante tres secuencias sintéticas. La primer secuencia consistió de siete pasos y un rendimiento total de 47%. En las otras ... -
Synthesis and Determination of Antitumor Activity of Jacaranone and Synthetic Analogs
(2018)Natural product jacaranone, 1, and three analog derivatives were synthesized and their apoptotic and necrotic activity against four cancer cell lines was tested. One of these derivatives 7, was more active than the natural ... -
Nuevos métodos de preparación del 1,3-Dilitiopropino y sus aplicaciones en la síntesis de compuestos bioactivos
(2006)Se desarrolló un método para la preparación del 1,3-dilitiopropino, a partir de bromuro de propargilo. Este procedimiento ha sido usado para desarrollar nuevos métodos de síntesis de alcoholes homopropargílicos, 1,5-diinos, ... -
Stereospecific Synthesis of (E, Z)- and (Z, Z)-Hexadeca-10,12-dienal. Sex Pheromone Components of Diaphania hyalinata
(1998)Isomeric (E,Z)- and (Z,Z)-hexadeca-10,12-dienal were prepared, stereospecifically, in 51% and 43% overall yields from dec-1-yne. -
Propargylation of Carbonyl Compounds: An Efficient Method for the Synthesis of Homopropargyl Alcohols
(1998)Controlled dilithiation of allene, with two equivalents of n-butytlithium, produces the propargyl dianion 5. The latter couple efficiently with carbonyl compounds to produce homopropargyl alcohols in high yields. -
Biological and dosimetric evaluation of [11C]S-adenosyl methionine as a potential agent for prostate cancer diagnosis
(2018)Introduction: [11C]Choline ([11C]COL) has been widely used for prostate cancer diagnosis; however, this radiopharmaceutical is not recommended for patients with a low absolute PSA value (< 1 ng/mL) due to its limited ...
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