Listar Ciencias básicas por título
Mostrando ítems 1680-1699 de 3121
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Janzen-Connell effects shape gene flow patterns and realized fitness in the tropical dioecious tree Spondias purpurea (ANACARDIACEAE)
(2020-03-12)Pollination and seed dispersal patterns determine gene flow within plant populations. In tropical forests, a high proportion of trees are dioecious, insect pollinated and dispersed by vertebrates. Dispersal vectors and ... -
Joaquín Bernardo García Castro, 1944-2001
(2002-04)No nos recuperábamos del pesar causado por la muerte de la ex directora del Jardín Botánico Lankester, Dora Emilia Mora-Retana, cuando recibimos con gran dolor la noticia del fallecimiento de su gran amigo colaborador, el ... -
Karma, a new genus in the Pleurothallidinae (Orchidaceae)
(2023-06-29)The new generic name Karma (Orchidaceae: Pleurothallidinae) is proposed to substitute the concept of Tubella (Luer) Archila [2009], which is illegitimate on account of the prior homonym Tubella Archila [2006], a genus in ... -
Karyotype of the yellow-bellied sea snake, Pelamis platurus
(1980)In this paper we describe the karyotype of the yellow-bellied sea snake, Pelamis platurus from Costa Rica. The diploid number is 38 chromosomes, with 20 macrochromosomes and 18 microchromosomes. The pairs 1 and 2 are ... -
Kaurene diterpenes from Mikania vitifolia
(1998)From the aerial parts of Mikania vitifolia three new ent-kaurane diterpenes, ent-7α-cinnamoyloxy-15β-hydroxy-kaur-16-en-19-oic acid, ent-15β-cinnamoyloxy-7α-hydroxy-kaur-16-en-19-oic acid and ent-15β-hydroxy-7α-(E)-lachn ... -
Key to the species of the genus Scleria (Cyperaceae) in Costa Rica based on the morphology of achenes
(2016)We described the achenes of 21 species of the genus Scleria reported in Costa Rica using 16 morphological characters and developed a key based only on achene characteristics. Specimens deposited in herbaria in Costa Rica ... -
Kinetik und Thermodynamik einer thermischen Umlagerung in der λ5-Phosphorinreihe. Die Umlagerung von 1-Acetoxy-λ5-phosphorin* in 6-Acetyl-1-oxo-1λ5-phospha-2,,4-cyclohexadien
(1974-03)Beim Erhitzen von 1-Acetoxy-1-isopropoxy-2,4,6-triphenyl-λ5-phosphorin (1c) in 1,4-Dioxan entsteht 6c-Acetyl-1-isopropoxy-1r-oxo-2,4,6-triphenyl-1λ5-phospha-2,4-cyclohexadien (2c), das durch säurekatalysierte Epimerisierung ... -
Kinship, association, and social complexity in bats
(2019-01)Among mammals, bats exhibit extreme variation in sociality, with some species living largely solitary lives while others form colonies of more than a million individuals. Some tropical species form groups during the day ... -
Laboratorio de matemática: Fascículo #1
(Universidad de Costa Rica. Sede de Occidente, 1992, 1992)Este fascículo consiste en una serie de guías para utilizar los modelos didácticos correspondientes a diversos conceptos matemáticos incluidos en los programas de los cursos de la enseñanza primaria y secundaria. Incluye ... -
Lack of early inbreeding depression and distribution of selfing rates in the neotropical emergent tree Ceiba pentandra: Assessment from several reproductive events
(2015)Premise of the study: Selfing and mixed mating systems are prevalent in many flowering plants. Purging of genetic load can occur in these species, reducing negative effects of selfing. Long‐term studies of the temporal and ... -
Lactrodectismo en Costa Rica
(2017)Se reporta un accidente causado por la araña Latrodectus geometricus, incluida en el grupo conocido como “viudas negras”, en Costa Rica. El accidente le ocurrió a una mujer de 27 años vecina de la ciudad de Cartago, en su ... -
Lacunary discrete spherical maximal functions
(2019)We prove new l^p(Z^d) bounds for discrete spherical averages in dimensions d greater than or equal to 5. We focus on the case of lacunary radii, first for general lacunary radii, and then for certain kinds of highly ... -
Laelia Lindl. [with a new combination]
(2022-02)Se presentan, discuten e ilustran especies costarricenses del género Laelia (Orchidaceae). Una nueva combinación, Laelia lueddemannii subsp. costaricana, se propone. -
Lamellar fluctuations melt ferroelectricity
(2023)We consider a standard Ginzburg-Landau model of a ferroelectric whose electrical polarization is coupled to gradients of elastic strain [1–4]. At the harmonic level, such flexoelectric interaction is known to hybridize ... -
Landau theory and giant room-temperature barocaloric effect
(2017-10-17)The structural phase transitions of MF3 (M = Al, Cr, V, Fe, Ti, Sc) metal trifluorides are studied within a simple Landau theory consisting of tilts of rigid MF6 octahedra associated with soft antiferrodistortive optic ... -
Landing manoeuvres predict roost-site preferences in bats
(2022-11-11)Roosts are vital for the survival of many species, and how individuals choose one site over another is affected by various factors. In bats, for example, species may use stiff roosts such as caves or compliant ones such ... -
Lankester Botanical Garden: Fifty years spent with enthusiasm
(2023-11)The preservation of the Lankester Garden in Costa Rica is the greatest conservation effort made by those who love orchids. -
Lankester-Garten, der Botanische Garten in Cartago, Costa Rica
(2002)The Lankester Botanical Garden of the University of Costa Rica was founded in 1973, it was named in honor of the English natural scientist and previous owner Charles H. Lankester (1879-1969). This garden is internationally ...