Browsing Ciencias básicas by Title
Now showing items 2937-2956 of 3078
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Ultrastructural and microbial analyses of cellulose degradation in leaf-cutter ant colonies
(2017)Leaf-cutter ants (Atta and Acromyrmex) use fresh leaves to cultivate a mutualistic fungus (Leucoagaricus gongylophorus) for food in underground gardens. A new ant queen propagates the cultivar by taking a small fragment ... -
Ultrastructural demonstration of the model of Litopenaeus vannamei (Crustacea, Penaeidae) male sexual maturation and spermatozoal capacitation
(2016)The present study demonstrates ultrastructurally the model of Litopenaeus vannamei male sexual maturation and spermatozoal capacitation. The results show that phase 1 of the model occurred in the seminiferous tubules and ... -
Ultrastructure and histology of organogenesis induced from shoot tips of maize (Zea mays, Poaceae)
(Revista de Biología Tropical; vol.57(supl.1), 2009-11)Shoot tips of maize (Zea mays L.) were cultured on Murashige and Skoog medium supplemented with 2 mg/l BA +1 mg/l 2,4-D +40 mg/l, to investigate phases of ontogenetic development. The study used light microscopy as well ... -
Ultrastructure of Deinopis egg sac (Araneae: Deinopidae)
(2014)Attacks by predators and parasitoids on spider eggs are common. To counteract their negative effect, spiders have evolved a series of behaviours and features related to their egg sacs. In the genus Deinopis (Deinopidae) ... -
Uncovering the Cultivable Microbial Diversity of Costa Rican Beetles and Its Ability to Break Down Plant Cell Wall Components
(2014)Coleopterans are the most diverse insect order described to date. These organisms have acquired an array of survival mechanisms through their evolution, including highly efficient digestive systems. Therefore, the coleopteran ... -
Unearthing 20th-century treasures: new records of deep-sea crustaceans from the Costa Rican Pacific
(2020-09)We report on 13 species collected during the 1973 expedition onboard the MY “Velero IV”: seven Euphausiidae (krill), two Benthesicymidae shrimp, two Sergestidae shrimp, one Acanthephyridae shrimp, and one Portunidae crab. ... -
Uniform sparse bounds for discrete quadratic phase Hilbert transforms
(2017-09)Consider the discrete quadratic phase Hilbert Transform acting on $\ell^{2}(\mathbb{Z})$ finitely supported functions $$ H^{\alpha} f(n) : = \sum_{m \neq 0} \frac{e^{i\alpha m^2} f(n - m)}{m}. $$ We prove that, ... -
Unraveling the whole story: An Ultraestructural study of the common bean "amachamiento" disease caused by Aphelencoides besseyi
(2019-07-21)Se identificó Aphelencoides besseyi como responsable del amachamiento del frijol -
Unusual Microbial Xylanases from Insect Guts
(2004-06-07)Recombinant DNA technologies enable the direct isolation and expression of novel genes from biotopes containing complex consortia of uncultured microorganisms. In this study, genomic libraries were constructed from microbial ... -
Unusual records of waterbirds in Costa Rica: possible connection to El Niño 2015-2016
(2016)These records were reported during the winter migrations in 2015 and 2016; five of the six species were apparently migrating from their reproductive sites in North America to their wintering grounds on the Pacific coast ... -
Unveiling the Hidden Bat Diversity of a Neotropical Montane Forest
(2016-10)Mountain environments, characterized by high levels of endemism, are at risk of experiencing significant biodiversity loss due to current trends in global warming. While many acknowledge their importance and vulnerability, ... -
Updated checklist and analysis of completeness of the marine fish fauna of Isla del Coco, Pacific of Costa Rica
(2016)Isla del Coco, Costa Rica, is one of the five groups of oceanic islands of the Eastern Tropical Pacific (ETP), and is considered one of the most diverse. Since the mid-19th century, it has been the target of a number of ... -
UPLC-HRMS Polyphenolic Characterization, Contents and Antioxidant Activity of Zingiber officinale Roscoe rhizomes from Costa Rica
(2022)Zingiber offcinale Roscoe rhizomes have been associated with multiple health benefits, such as blocking blood clotting, digestive and antinausea effects and aid in respiratory conditions. These effects have been linked ... -
Upwelling Increases Net Primary Production of Corals and Reef-Wide Gross Primary Production Along the Pacific Coast of Costa Rica
(2015-12-23)Photosynthetic production is a key ecosystem service provided by tropical coral reefs, but knowledge about the contribution of corals and other reef-associated organisms and the controlling environmental factors is scarce. ... -
Urban endoliths: incidental microbial communities occurring inside concrete
(2023-03-30)Concrete is now a prevalent type of synthetic rock, and its production and usage have major environmental implications. Yet, assessments of ordinary concrete have rarely considered that concrete itself is potential habitat ... -
Urban noise influences vocalization structure in the House Wren Troglodytes aedon
(2013)Urban habitats are noisy and constrain acoustic communication in birds. We analysed the effect of anthropogenic noise on the vocalization characteristics of House Wrens Troglodytes aedon at two sites with different noise ... -
Urbanization has opposite effects on the territory size of two passerine birds
(2020-04-28)Background: Urban expansion has been identified as one of the leading drivers of biodiversity change or loss. For birds, urbanization is specifically related to survival, breeding success, and territory size. Understanding ... -
Urbanization, habitat extension and spatial pattern, threaten a Costa Rican endemic bird
(2021)Introduction: Migration of people from rural environments to cities has accelerated urbanization and modified the landscape as well as the ecological processes and communities in these areas. The Costa Rican endemic Cabanis´s ... -
Use of a theoretical prediction method and quantum chemical calculations for the design, synthesis and experimental evaluation of three green corrosion inhibitors for mild steel
(2020)Three phenylmethanimine derivatives (Schiff bases) were designed after a theoretical prediction of their corrosion inhibition efficiencies and a corroboration through the use of quantum chemical calculations. The molecules ...