139 research outputs found
Characterizing Salinity Tolerance in Greenhouse Roses
Among ornamental plants, roses (Rosa L.) are considered the most
economically important, being among the most popular garden shrubs, as well
as the favorite cut flowers sold by florists. In the past roses have been classified
as fairly salt-sensitive, however, recent nutrition studies suggest that they may
actually tolerate moderate to relatively high salinities. The general objective of
this research was to reassess the limits of tolerance to salinity of roses and the
influence of the rootstock used, to determine the ameliorative properties of
supplemental Ca2+ on the response to salt stress, and to establish the influence
of Na+- and Cl--counter ions on the detrimental effects caused by these
salinizing elements.
The NaCl or NaCl-CaCl2-salinity tolerance limit for greenhouse roses,
although greatly influenced by the rootstock, was between 12 and 15 mmol.L-1.
Plants grafted on ?Manetti? sustained their productivity/quality characteristics for
longer time periods, tolerated greater salinity concentrations, and accumulated
less Cl- and Na+ in leaves of flowering shoots than those grafted on ?Natal Briar?,
confirming the greater ability of the former rootstock to tolerate salt stress.
Supplementing the saline solution with 0-10 mmol.L-1 Ca2+ (as CaSO4) did
not alleviate the harmful effects caused by NaCl-salt stress (12 mmol.L-1) on the
productivity and quality responses of roses.
The detrimental effects caused by Na- and Cl-based salinity were greatly
influenced by the composition of the salt mixtures (i.e. their counter ions). Sodium sulfate and CaCl2 were the least harmful salts; NaCl had intermediate
effects, while NaNO3 and KCl were the most deleterious. Among the most
distinguishable effects caused by the more toxic Na+ and Cl- counter ions were
lower osmotic potential (piSS) and greater electrical conductivity (ECSS) of the
salinized solutions, markedly increased uptake and/or transport of either Na+ or
Cl- to the flowering shoot leaves, and altered uptake and/or transport of other
mineral nutrients.
Computations of the saline solutions? chemical speciation revealed that
salts containing divalent ions had lower ionization and exhibited greater ion
associations compared to monovalent ion salts, rendering a lower number in
free ions/molecules in solution which caused greater SS and lower ECSS in
those solutions
An annotated list of the Lepidoptera of Honduras
A biodiversity inventory of the Lepidoptera of Pico Bonito National Park and vicinity, in the Department of Atlantida of northern Honduras, was initiated in 2009 to obtain baseline data. We present a revised checklist of Honduran butterfly species (updated from the initial 1967 lists), as well as the first comprehensive list of Honduran moths. Our updated list includes 550 species of Papilionoidea, 311 Hesperioidea, and 1,441 moth species
An annotated list of the Lepidoptera of Honduras
A biodiversity inventory of the Lepidoptera of Pico Bonito National Park and vicinity, in the Department of Atlantida of northern Honduras, was initiated in 2009 to obtain baseline data. We present a revised checklist of Honduran butterfly species (updated from the initial 1967 lists), as well as the first comprehensive list of Honduran moths. Our updated list includes 550 species of Papilionoidea, 311 Hesperioidea, and 1,441 moth species
Biosynthesis of Silver Nanoparticles on Orthodontic Elastomeric Modules: Evaluation of Mechanical and Antibacterial Properties
Abstract: In the present study, silver nanoparticles (AgNPs) were synthesized in situ on orthodontic elastomeric modules (OEM) using silver nitrate salts as metal-ion precursors and extract of the plant Hetheroteca inuloides (H. inuloides) as bioreductant via a simple and eco-friendly method. The synthesized AgNPs were characterized by UV-visible spectroscopy; scanning electron microscopy-energy-dispersive spectroscopy (SEM-EDS) and transmission electron microscopy (TEM). The surface plasmon resonance peak found at 472 nm confirmed the formation of AgNPs. SEM and TEM images reveal that the particles are quasi-spherical. The EDS analysis of the AgNPs confirmed the presence of elemental silver. The antibacterial properties of OEM with AgNPs were evaluated against the clinical isolates Streptococcus mutans, Lactobacillus casei, Staphylococcus aureus and Escherichia coli using agar diffusion tests. The physical properties were evaluated by a universal testing machine. OEM with AgNPs had shown inhibition halos for all microorganisms in comparison with OEM control. Physical properties increased with respect to the control group. The results suggest the potential of the material to combat dental biofilm and in turn decrease the incidence of demineralization in dental enamel, ensuring their performance in patients with orthodontic treatmentUAEME
Geographic Population Structure of the Sugarcane Borer, Diatraea saccharalis (F.) (Lepidoptera: Crambidae), in the Southern United States
The sugarcane borer moth, Diatraea saccharalis, is widespread throughout the Western Hemisphere, and is considered an introduced species in the southern United States. Although this moth has a wide distribution and is a pest of many crop plants including sugarcane, corn, sorghum and rice, it is considered one species. The objective was to investigate whether more than one introduction of D. saccharalis had occurred in the southern United States and whether any cryptic species were present. We field collected D. saccharalis in Texas, Louisiana and Florida in the southern United States. Two molecular markers, AFLPs and mitochondrial COI, were used to examine genetic variation among these regional populations and to compare the sequences with those available in GenBank and BOLD. We found geographic population structure in the southern United States which suggests two introductions and the presence of a previously unknown cryptic species. Management of D. saccharalis would likely benefit from further investigation of population genetics throughout the range of this species
USO DE APLICACIONES DE LA WEB 2.0 PARA LA EVALUACIÓN DEL APRENDIZAJE SIGNIFICATIVO (USE OF WEB 2.0 APPLICATIONS FOR THE EVALUATION OF SIGNIFICANT LEARNING)
Ante las tendencias tecnológicas y las opciones que brindan las aplicaciones de la Web 2.0 para múltiples dispositivos, se aspira estudiar, si las herramientas de la Web 2.0 incrementan el aprendizaje significativo, contribuyendo a potenciar el rendimiento académico, se utilizaron las Apps Kahoot!, Socrative, Drive y Formularios de la Suite de Google. La investigación es cuantitativa, tipo correlacional y diseño cuasi experimental. Los resultados obtenidos muestran; un incremento en el aprovechamiento de un 9.83%, detectando una mejora en el logro de las competencias establecidas en la unidad de aprendizaje de Tecnologías de la Comunicación y Gestión de Información, a la par se estudiaron aspectos pedagógicos y técnicos de las Apps utilizadas, los resultados prueban que 100% de los estudiantes opinaron de Muy buena (50%) a buena (50%) su evaluación educativa con las aplicaciones implementadas, apoyando la ventaja de utilizar herramientas de la web 2.0 para la evaluación del aprendizaje significativo.Given the technological trends and the options offered by Web 2.0 applications for multiple devices, we aspire to study, if Web 2.0 tools increase meaningful learning, contributing to enhance academic performance, Kahoot! Socrative Apps were used, Drive and Forms of the Google Suite. The research is quantitative, correlational type and quasi-experimental design. The results obtained show; an increase in the use of 9.83%, detecting an improvement in the achievement of the competences established in the Learning Unit of Communication Technologies and Information Management, at the same time pedagogical and technical aspects of the Apps used were studied. results prove that 100% of students rated Very good (50%) as good (50%) their educational evaluation with the applications implemented, supporting the advantage of using Web 2.0 tools for the evaluation of meaningful learning
Toward reconstructing the evolution of advanced moths and butterflies (Lepidoptera: Ditrysia): an initial molecular study
<p>Abstract</p> <p>Background</p> <p>In the mega-diverse insect order Lepidoptera (butterflies and moths; 165,000 described species), deeper relationships are little understood within the clade Ditrysia, to which 98% of the species belong. To begin addressing this problem, we tested the ability of five protein-coding nuclear genes (6.7 kb total), and character subsets therein, to resolve relationships among 123 species representing 27 (of 33) superfamilies and 55 (of 100) families of Ditrysia under maximum likelihood analysis.</p> <p>Results</p> <p>Our trees show broad concordance with previous morphological hypotheses of ditrysian phylogeny, although most relationships among superfamilies are weakly supported. There are also notable surprises, such as a consistently closer relationship of Pyraloidea than of butterflies to most Macrolepidoptera. Monophyly is significantly rejected by one or more character sets for the putative clades Macrolepidoptera as currently defined (<it>P </it>< 0.05) and Macrolepidoptera excluding Noctuoidea and Bombycoidea sensu lato (<it>P </it>≤ 0.005), and nearly so for the superfamily Drepanoidea as currently defined (<it>P </it>< 0.08). Superfamilies are typically recovered or nearly so, but usually without strong support. Relationships within superfamilies and families, however, are often robustly resolved. We provide some of the first strong molecular evidence on deeper splits within Pyraloidea, Tortricoidea, Geometroidea, Noctuoidea and others.</p> <p>Separate analyses of mostly synonymous versus non-synonymous character sets revealed notable differences (though not strong conflict), including a marked influence of compositional heterogeneity on apparent signal in the third codon position (nt3). As available model partitioning methods cannot correct for this variation, we assessed overall phylogeny resolution through separate examination of trees from each character set. Exploration of "tree space" with GARLI, using grid computing, showed that hundreds of searches are typically needed to find the best-feasible phylogeny estimate for these data.</p> <p>Conclusion</p> <p>Our results (a) corroborate the broad outlines of the current working phylogenetic hypothesis for Ditrysia, (b) demonstrate that some prominent features of that hypothesis, including the position of the butterflies, need revision, and (c) resolve the majority of family and subfamily relationships within superfamilies as thus far sampled. Much further gene and taxon sampling will be needed, however, to strongly resolve individual deeper nodes.</p
Global genetic diversity of Aedes aegypti
Mosquitoes, especially Aedes aegypti, are becoming important models for studying invasion biology. We characterized genetic variation at 12 microsatellite loci in 79 populations of Ae. aegypti from 30 countries in six continents, and used them to infer historical and modern patterns of invasion. Our results support the two subspecies Ae. aegypti formosus and Ae. aegypti aegypti as genetically distinct units. Ae. aegypti aegypti populations outside Africa are derived from ancestral African populations and are monophyletic. The two subspecies co-occur in both East Africa (Kenya) and West Africa (Senegal). In rural/forest settings (Rabai District of Kenya), the two subspecies remain genetically distinct, whereas in urban settings, they introgress freely. Populations outside Africa are highly genetically structured likely due to a combination of recent founder effects, discrete discontinuous habitats and low migration rates. Ancestral populations in sub-Saharan Africa are less genetically structured, as are the populations in Asia. Introduction of Ae. aegypti to the New World coinciding with trans-Atlantic shipping in the 16th to 18th centuries was followed by its introduction to Asia in the late 19th century from the New World or from now extinct populations in the Mediterranean Basin. Aedes mascarensis is a genetically distinct sister species to Ae. aegypti s.l. This study provides a reference database of genetic diversity that can be used to determine the likely origin of new introductions that occur regularly for this invasive species. The genetic uniqueness of many populations and regions has important implications for attempts to control Ae. aegypti, especially for the methods using genetic modification of populations.Centro de Estudios Parasitológicos y de Vectore
Global genetic diversity of Aedes aegypti
Mosquitoes, especially Aedes aegypti, are becoming important models for studying invasion biology. We characterized genetic variation at 12 microsatellite loci in 79 populations of Ae. aegypti from 30 countries in six continents, and used them to infer historical and modern patterns of invasion. Our results support the two subspecies Ae. aegypti formosus and Ae. aegypti aegypti as genetically distinct units. Ae. aegypti aegypti populations outside Africa are derived from ancestral African populations and are monophyletic. The two subspecies co-occur in both East Africa (Kenya) and West Africa (Senegal). In rural/forest settings (Rabai District of Kenya), the two subspecies remain genetically distinct, whereas in urban settings, they introgress freely. Populations outside Africa are highly genetically structured likely due to a combination of recent founder effects, discrete discontinuous habitats and low migration rates. Ancestral populations in sub-Saharan Africa are less genetically structured, as are the populations in Asia. Introduction of Ae. aegypti to the New World coinciding with trans-Atlantic shipping in the 16th to 18th centuries was followed by its introduction to Asia in the late 19th century from the New World or from now extinct populations in the Mediterranean Basin. Aedes mascarensis is a genetically distinct sister species to Ae. aegypti s.l. This study provides a reference database of genetic diversity that can be used to determine the likely origin of new introductions that occur regularly for this invasive species. The genetic uniqueness of many populations and regions has important implications for attempts to control Ae. aegypti, especially for the methods using genetic modification of populations.Centro de Estudios Parasitológicos y de Vectore
- …