925 research outputs found
Phylogeography of Acartia tonsa Dana, 1849 (Calanoida: Copepoda) and phylogenetic reconstruction of the genus Acartia Dana, 1846
The calanoid copepod, Acartia tonsa Dana, 1849 is one of the most abundant and well-studied estuarian species with a worldwide distribution. In this research, we use the mitochondrial cytochrome oxidase subunit I gene to study the phylogeography of A. tonsa by analyzing sequences from specimens collected in the western Gulf of Mexico (GOM) along with all sequences from previous research. We reconstruct the phylogeny for the genus Acartia Dana, 1846 and highlight numerous potential misidentifications of Acartia species deposited in GenBank. The incorrect taxonomy assigned to some of these sequences results in apparently paraphyletic relationships. This study demonstrates that A. tonsa is a species complex with multiple, deeply diverging, lineages of varying geographic affinities. Multiple new lineages are found in the Texas GOM that is basal to northwestern Atlantic lineages with phylogenetic connectivity also observed between Brazil and the Texas GOM. Results show two major phylogeographic breaks in the North American continent, one at the border between the Gulf of Mexico and the Northwest Atlantic, and the other at about 35° N. One of the major clades in the A. tonsa species complex shows a clear pattern of divergence that follows the prevailing currents. Within this clade, older lineages are found in the western GOM while newer lineages are found in the eastern GOM and the southern coast of the northwest Atlantic, with the youngest lineages diversifying in the north. The results show that A. tonsa can be used as a model species for observing phylogeographical structuring of coastal plankton along the American continent
The complete mitochondrial genome of Tanacetipathes thamnea Warner, 1981 (Antipatharia: Myriopathidae)
Specimens of the black coral Tanacetipathes thamnea were collected from the Northwestern Gulf of Mexico. The complete mitochondrial genome of one of these specimens was obtained from genomic DNA by next-generation sequencing technology on the Illumina HiSeq 2500. Only three species of black corals have a completely sequenced mitochondrial genome. These were used to reconstruct the phylogeny for the order Antipatharia. The mitochondrial genome of T. thamnea is 17,712 base pairs and contains 13 protein-coding genes, 2 ribosomal RNAs, and 2 transfer RNAs in the following order: 16s RNA, COX3, COX1 (with intron), ND4L, COX2, ND4, ND6, ATP8, ATP6, and ND5 (with intron and copies of ND1 and ND3), tRNA-Trp, ND2, 12s RNA, CYTB, tRNA-Met. The gene arrangement is the same as that for Myriopathes japonica with a nearly identical sequence (99.35% identical). These results show that the mitochondrial genome within the family Myriopathidae is highly conserved
Mitogenomic phylogenetic analyses of Leptogorgia virgulata and Leptogorgia hebes (Anthozoa: Octocorallia) from the Gulf of Mexico provides insight on Gorgoniidae divergence between Pacific and Atlantic lineages
The use of genetics in recent years has brought to light the need to reevaluate the classification of many gorgonian octocorals. This study focuses on two Leptogorgia species—Leptogorgia virgulata and Leptogorgia hebes—from the northwestern Gulf of Mexico (GOM). We target complete mitochondrial genomes and mtMutS sequences, and integrate this data with previous genetic research of gorgonian corals to resolve phylogenetic relationships and estimate divergence times. This study contributes the first complete mitochondrial genomes for L. ptogorgia virgulata and L. hebes. Our resulting phylogenies stress the need to redefine the taxonomy of the genus Leptogorgia in its entirety. The fossil-calibrated divergence times for Eastern Pacific and Western Atlantic Leptogorgia species based on complete mitochondrial genomes shows that the use of multiple genes results in estimates of more recent speciation events than previous research based on single genes. These more recent divergence times are in agreement with geologic data pertaining to the formation of the Isthmus of Panama
Early warning system for coffee rust disease based on error correcting output codes: a proposal
Colombian coffee producers have had to face the severe consequences of the coffee rust disease since it was first reported in the country in 1983. Recently, machine learning researchers have tried to predict infection through classifiers such as decision trees, regression Support Vector MaÂchines (SVM), non-deterministic classifiers and Bayesian Networks, but it has been theoretically and empirically demonstrated that combining multiple classifiers can substantially improve the classification perforÂmance of the constituent members. An Early Warning System (EWS) for coffee rust disease was therefore proposed based on Error Correcting Output Codes (ECOC) and SVM to compute the binary functions of Plant Density, Shadow Level, Soil Acidity, Last Nighttime Rainfall Intensity and Last Days Relative Humidity.Los productores de café colombianos han sufrido severas consecuencias por la Roya desde que fue reportada por primera vez en el paÃs en el año 1983. Recientemente, investigadores de aprendizaje automático han intentado predecir la roya a través de clasificadores como: arboles de deÂcisión, máquinas de vector de soporte, clasificadores no determinÃsticos y redes bayesianas, pero se ha demostrado teórica y empÃricamente que la combinación de múltiples clasificadores puede mejorar sustancialmente el rendimiento en la clasificación. En este sentido es propuesto un sistema de alerta temprana para la roya en el café, basado en códigos de salida de corrección de error y máquinas de vector de soporte para calcular las funciones binarias de la densidad de planta, el nivel de sombra, la acidez del suelo, la intensidad de lluvia en la última noche, y en últimos dÃas, con humedad relativa
Multiwavelength optical observations of chromospherically active binary systems. 1. Simultaneous H alpha, Na I D_1, D_2, and He I D_3 observations
This is the first paper of a series aimed at studying the chromosphere of active binary systems using the information provided for several optical spectroscopic features. Simultaneous H_α, Na I D_1, D_2, and He I D_3 spectroscopic observations are reported here for 18 systems. The chromospheric contribution in these Lines have been determined using the spectral subtraction technique. Very broad wings have been found in the subtracted H_α profile of some of the more active stars. These profiles are well matched using a two-components Gaussian fit (narrow and broad) and the broad component could be interpreted as arising from microflaring. Prominence-like extended material have been detected in a near-eclipse H_α observation of the system AR Lac. The excess emission found in the Na I D_1 and D_2 lines by application of the spectral subtraction technique and the behaviour of the H_α line in the corresponding simultaneous observations indicate that the filling-in of the core of these lines is a chromospheric activity indicator. For giant stars of the sample the He I D_3 line has been detected in absorption in the subtracted spectra. An optical flare has been detected in UX Ari and II Peg through the presence of the He I D_3 in emission incoincidence with the enhancement of the H_α emission
Association between the Use of Antibiotics and the Development of Acute Renal Injury in Patients Hospitalized for COVID-19 in a Hospital in the Peruvian Amazon
"Introduction: A significant antibiotic prescribing pattern associated with the COVID-19 pandemic has been described. Multiple protocols included empirical antimicrobials, leading to a substantial increase in antimicrobial consumption in medical care. A higher mortality rate is described among
patients diagnosed with COVID-19 who received antibiotics. Objectives: To determine the association
between the use of antibiotics and the development of acute renal injury in patients infected with
SARS-CoV-2 in patients treated at the Hospital II EsSalud de Ucayali, 2021. Methods: A cross-sectionalanalytical study was conducted, evaluating the medical records of patients admitted to the intensive
care unit between July 2020 and July 2021. For the statistical analysis, measures of central tendency
and dispersion, statistical hypothesis contrast tests were used in relation to acute kidney injury (AKI),
antibiotic use and associated factors, derived from linear regression models. Results: The factors that
were positively associated with the development of AKI were sepsis (aPR: 2.86; 95% CI: 1.26–6.43),
shock (aPR:2.49; 95% CI: 1.28–4.86), mechanical ventilation (aPR:9.11; 95% CI: 1.23–67.57), and use
of vancomycin (aPR: 3.15; 95% CI: 1.19–8.27). Conclusions: In the Peruvian Amazon, there is a high
consumption and inadequate prescription of antibiotics. The drugs most commonly used for the
treatment of COVID-19 were: aminoglycosides, vancomycin, ivermectin, azithromycin, tocilizumab,
and corticosteroids. The development of AKI among hospitalized patients was found to be related
to vancomycin administration. In addition, an association was found with the use of mechanical
ventilation, a high body mass index, and the presence of complications such as sepsis or shock.
Therefore, inappropriate antibiotic use for COVID-19 has been associated with multiple negative
outcomes and consequences.
Sistema de alerta temprana para la roya en el café basado en códigos de salida de corrección de error: una propuesta
Colombian coffee producers have had to face the severe consequences of the coffee rust disease since it was first reported in the country in 1983. Recently, machine learning researchers have tried to predict infection through classifiers such as decision trees, regression Support Vector MaÂchines (SVM), non-deterministic classifiers and Bayesian Networks, but it has been theoretically and empirically demonstrated that combining multiple classifiers can substantially improve the classification perforÂmance of the constituent members. An Early Warning System (EWS) for coffee rust disease was therefore proposed based on Error Correcting Output Codes (ECOC) and SVM to compute the binary functions of Plant Density, Shadow Level, Soil Acidity, Last Nighttime Rainfall Intensity and Last Days Relative Humidity.Los productores de café colombianos han sufrido severas consecuencias por la Roya desde que fue reportada por primera vez en el paÃs en el año 1983. Recientemente, investigadores de aprendizaje automático han intentado predecir la roya a través de clasificadores como: arboles de deÂcisión, máquinas de vector de soporte, clasificadores no determinÃsticos y redes bayesianas, pero se ha demostrado teórica y empÃricamente que la combinación de múltiples clasificadores puede mejorar sustancialmente el rendimiento en la clasificación. En este sentido es propuesto un sistema de alerta temprana para la roya en el café, basado en códigos de salida de corrección de error y máquinas de vector de soporte para calcular las funciones binarias de la densidad de planta, el nivel de sombra, la acidez del suelo, la intensidad de lluvia en la última noche, y en últimos dÃas, con humedad relativa
Formation and characterization of crosslinks, including Tyr-Trp species, on one electron oxidation of free Tyr and Trp residues by carbonate radical anion
Dityrosine and ditryptophan bonds have been implied in protein crosslinking. This is associated with oxidative stress conditions including those involved in neurodegenerative pathologies and age-related processes. Formation of dityrosine and ditryptophan derives from radical–radical reactions involving Tyr˙ and Trp˙ radicals. However, cross reactions of Tyr˙ and Trp˙ leading to Tyr–Trp crosslinks and their biological consequences have been less explored. In the present work we hypothesized that exposure of free Tyr and Trp to a high concentration of carbonate anion radicals (CO(3)˙(−)), under anaerobic conditions, would result in the formation of Tyr–Trp species, as well as dityrosine and ditryptophan crosslinks. Here we report a simple experimental procedure, employing CO(3)˙(−) generated photochemically by illumination of a Co(iii) complex at 254 nm, that produces micromolar concentrations of Tyr–Trp crosslinks. Analysis by mass spectrometry of solutions containing only the individual amino acids, and the Co(iii) complex, provided evidence for the formation of o,o′-dityrosine and isodityrosine from Tyr, and three ditryptophan dimers from Trp. When mixtures of Tyr and Trp were illuminated in an identical manner, Tyr–Trp crosslinks were detected together with dityrosine and ditryptophan dimers. These results indicate that there is a balance between the formation of these three classes of crosslinks, which is dependent on the Tyr and Trp concentrations. The methods reported here allow the generation of significant yields of isolated Tyr–Trp adducts and their characterization. This technology should facilitate the detection, and examination of the biological consequences of Tyr–Trp crosslink formation in complex systems in future investigations
Multiwavelength optical observations of chromospherically active binary systems - II. EZ Pegasi
The star EZ Peg, long ago classified as cataclysmic variable, has been shown to be a chromospherically active binary system of the RS CVn-type. In this paper we have analysed, using the spectral subtraction technique, simultaneous spectroscopic observations of the Hα, Hβ, Na I D_1 and D_2, He I D_3, Mg I b triplet, Ca II H & K, and Ca II infrared triplet lines. We have found that the hot component is the active star of the system, showing strong emission in the Hα, Ca Ir H & K, Hε, and Ca II IRT lines, and a strong filling-in of the Hβ line, however the Na I D_1 and D_2 and Mg I b triplet lines do not present filled-in. The He I D_3 could present a total filling-in due to microflaring. The observed variations (in different epochs and with the orbital phase) of the different activity indicators, formed at different height in the chromosphere, are correlated. Very broad wings have been found in the subtracted profiles of Hα and Ca II IRT λ8498 and λ8662 lines. These profiles are well matched using a two-component Gaussian fit (narrow and broad) and the broad component could be interpreted as arising from microflaring. The higher luminosity class of the hot component, that our spectra seem to indicate, could explain why the hot component is the active star of the system
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A consensus definition for lamellar macular hole
Background: A consensus on an optical coherence tomography (OCT) definition of lamellar macular hole (LMH) and similar conditions is needed.
Methods: The panel reviewed relevant peer-reviewed literature to reach a consensus on LMH definition and to differentiate LMH from other similar conditions.
Results: The panel reached a consensus on the definition of 3 clinical entities: LMH, epiretinal membrane (ERM) foveoschisis and macular pseudohole (MPH). LMH definition is based on 3 mandatory criteria and 3 optional anatomical features. The 3 mandatory criteria are the presence of irregular foveal contour, the presence of a foveal cavity with undermined edges, and the apparent loss of foveal tissue. Optional anatomical features include the presence of epiretinal proliferation, the presence of a foveal bump and the disruption of the ellipsoid line. ERM foveoschisis definition is based on 2 mandatory criteria: the presence of ERM and the presence of schisis at the level of Henle’s fiber layer. Three optional anatomical features can also be present: the presence of microcystoid spaces in the inner nuclear layer (INL), an increase of retinal thickness, and the presence of retinal wrinkling. MPH definition is based on 3 mandatory criteria and 2 optional anatomical features. Mandatory criteria include the presence of a foveal sparing ERM, the presence of a steepened foveal profile and an increased central retinal thickness. Optional anatomical features are the presence of microcystoid spaces in the INL and a normal retinal thickness.
Conclusions: The use of the proposed definitions may provide uniform language for clinicians and future research
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