Listar Ciencias básicas por título
Mostrando ítems 1514-1533 de 3122
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Híbridos silvestres de patos (Anseriformes: Anatidae) registrados en Costa Rica
(2016-09)Informamos la existencia de tres híbridos silvestres de patos en Costa Rica, basados en observaciones esporádicas en el país. Adicionalmente, proveemos una explicación de cuáles, serían las especies que dieron origen a ... -
Homoplasious colony morphology and mito-nuclear phylogenetic discordance among Eastern Pacific octocorals
(2016)Octocorals are a diverse and ecologically important group of cnidarians. However, the phylogenetic relationships of many octocoral groups are not well understood and are based mostly on mitochondrial sequence data. In ... -
Homopropargyl alcohol 1,1-diphenylbut-3-yn-1-ol
(2018)The asymmetric unit of the title compound, C16H14O, contains one molecule with a central carbon atom having a distorted tetrahedral geometry made of a propargylic fragment, a hydroxy group and two aromatic rings. ... -
Homopropargyl alcohol 5,5-diphenylpent-2-yne-1,5-diol
(2018)In the title compound, C17H16O2, the central carbon atom has a distorted tetrahedral geometry [spread of angles = 105.71 (8)–112.75 (9)°] for its bonds to a homopropargylic but-2-yn-1-ol moiety, a hydroxy group and two ... -
Hopf algebras in noncommutative geometry
(2003)We give an introductory survey to the use of Hopf algebras in several problems of noncommutative geometry. The main example, the Hopf algebra of rooted trees, is a graded, connected Hopf algebra arising from a universal ... -
Horichia dressleri. A new genus recorded for Costa Rica and a truly rare orchid?
(2017)Orchid collectors, as well as scientists, know that some species are rarer than others. “Know” should perhaps be used in this context with some caution as, in general, rarity is something closer to a perception than ... -
Horichia Jenny
(2022)Rarity, in orchids, is often closer to a perception than to a specific category of frequency, assessed on the basis of documented data. Rare species are frequently only a way to say that they are rarely seen in living ... -
Hot carrier extraction from multilayer graphene
(2016)Hot carriers in semiconductor or metal nanostructures are relevant, for instance, to enhance the activity of oxide-supported metal catalysts or to achieve efficient photodetection using ultrathin semiconductor layers. ... -
House Wrens Troglodytes aedon reduce repertoire size and change song element frequencies in response to anthropogenic noise
(2020-06-09)Anthropogenic noise (≤ 3 kHz) can affect key features of birds’ acoustic communication via two different processes: (1) song-learning, because songbirds need to hear themselves and other birds to crystallize their song, ... -
How many species of Pleurothallidinae are there?
(2019)Subtribe Pleurothallidinae is possibly the most species-rich of all orchid groups. Nevertheless, they are a young group of plants in terms of scientific learning. The last three decades have been the most active with respect ... -
Hub thread removal behaviour in the orb weaver Leucauge mariana (Araneae: Tetragnathidae)
(2020-11-05)Many orb-weaving spiders break the central lines of the hub at the end of web construction. Nevertheless, very little is known of how spiders break these lines and whether this behaviour differs among taxa. Here, we describe ... -
Human Influences On Eastern Tropical Pacific Coral Communities and Coral Reefs
(2016)Coral reefs world-wide have been impacted by direct and indirect human activity and natural disturbances. This has led to the degradation and disappearance of many reef structures. On a basin-wide scale, the natural impact ... -
Human waste used as nesting material affects nest cooling in the clay-colored thrush
(2021-09-01)The internal temperature of nests largely depends on the materials used in their construction because the characteristics of each material affect the isolation of nest walls. In urban environments, the availability of natural ... -
Human-Induced Changes in the Hydrology of the Western United States
(2008-02-22)Observations have shown that the hydrological cycle of the western United States changed significantly over the last half of the 20th century. We present a regional, multivariable climate change detection and attribution ... -
Humedales del Parque Nacional Chirripó, Costa Rica: características, relaciones geomorfológicas y escenarios de cambio climático
(2018-12)The geomorphological, climatological and hydrological characteristics of the high Andean wetlands of the Chirripó National Park (PNCh) are analyzed. The PNCh is located in south-central Costa Rica, Central America. This ... -
Hundreds of nuclear and plastid loci yield novel insights into orchid relationships
(2021)PREMISE: The inference of evolutionary relationships in the species- rich family Orchidaceae has hitherto relied heavily on plastid DNA sequences and limited taxon sampling. Previous studies have provided a robust plastid ... -
(Hydro)climatological studies of climate change and variability in Central America
(2018-06-26)This is the presentation of Hugo Hidalgo at the CORDEX Central America and South America Training Workshop on Downscaling Techniques, in La Paz, Bolivia, June 25 to 27, 2018. -
Hydro-Climatic Variability and Change in Central America. Supporting Risk Reduction Through Improved Analyses and Data
(2017)Floods and droughts are frequent in Central America and cause large social, economic and environmental impacts. A crucial step in disaster risk reduction is to have a good understanding of the causing mechanisms of extreme ... -
Hydrogen production by immobilized Synechocystis sp. PCC 6803
(2016)The ability of the immobilized Synechocystis sp. PCC 6803 cells to produce hydrogen via an indirect light driven process was investigated. Cells were successfully immobilized in a calcium alginate gel matrix. Beads were ... -
Hydrological climate change projections for Central America
(Journal of Hydrology 495: 94–112, 2013-05-04)Runoff climate change projections for the 21st century were calculated from a suite of 30 General Circulation Model (GCM) simulations for the A1B emission scenario in a 0.5 0.5 grid over Central America. The GCM data ...