456 research outputs found
Is there any genetic variation among native mexican and argentinian populations of Dalbulus maidis (Hemiptera: Cicadellidae)?.
The corn leafhopper Dalbulus maidis (Delong & Wolcott) (Hemiptera: Cicadellidae) originated in Mexico, but is found from southeastern and southwestern USA to Argentina. Differences in reproductive and phenotypic traits between Mexican (native) and Argentinian (adventive) populations have been previously reported, but information on their genetic variation is currently unavailable. The objective was to investigate possible genetic variability among D. maidis populations collected in Mexico on maize and maize relatives (annual and perennial teosintes) and on maize in Argentina. A region of the mitochondrial gene coding for the cytochrome oxidase subunit I (mtCOI) and the ribosomal internal transcribed spacer (ITS2) were sequenced and analyzed. We developed the forward and reverse primers for the DNA amplification of COI in D. maidis (dalCOI). Twenty two and 17 sequences for dalCOI and ITS2, respectively, were generated and analyzed. No genetic variation among Mexican and Argentinian populations was found in the ribosomal region and low genetic variation was found in the mitochondrial region. These results could be explained by the short evolutionary time scale, since both maize and the corn leafhopper moved throughout the Americas only in the most recent millenia, or in part to the limited host range, and thus a limited change in the corn leafhopper associated bacteria.Fil: Palomera, Veronica. Universidad de Guadalajara; MéxicoFil: Bertin, Sabrina. Universidad de Torino ; ItaliaFil: Rodriguez, Aaron. Universidad de Guadalajara; MéxicoFil: Bosco, Domenico. Universidad de Torino; ItaliaFil: Virla, Eduardo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Moya-Raygoza, Gustavo. Universidad de Guadalajara; Méxic
Clasificación de sitio de la Red de Acelerógrafos de Costa Rica basada en mediciones de VS30 y en el período fundamental
In this paper, a new seismic site classification for the Costa Rican Strong-Motion Network (CRSMN) is proposed. The soil profile classification of the Costa Rican Seismic Code based on the average shear-wave velocity of the top 30 m (VS30) is used as a reference. The site fundamental period (Tf) is included as a parameter to complement the existing characterization. For this, the VS30 measurements from 52 accelerometric stations are related to the site fundamental period obtained through horizontal-to-vertical spectral ratios (HVSR) using ground motion records from the Costa Rican Strong-Motion Database. The H/V ratios are estimated with 5% damped acceleration response spectra and with traditional Fourier amplitude spectra from the S-wave window. From the relation between VS30 and Tf, different ranges of Tf are assigned to the existing soil profile classification and a graph with three-lines and four-areas is proposed to classify the stations of the CRSMN.This research was partially funded by the National Emergency and Risk Prevention Law N° 8933 from Costa Rica and the UCREA funds from the University of Costa Rica through the project referenced as B9780.Peer ReviewedPostprint (published version
Phenomenological description of the states and in some even-even nuclei
A sixth-order quadrupole boson Hamiltonian is used to describe the states
and identified in several nuclei by various types of experiments.
Two alternative descriptions of energy levels are proposed. One corresponds to
a semi-classical approach of the model Hamiltonian while the other one provides
the exact eigenvalues. Both procedures yield close formulas for energies. The
first procedure involves four parameters, while the second involves a compact
formula with five parameters. In each case the parameters are fixed by a
least-square fit procedure. Applications are performed for eight even-even
nuclei.
Both methods yield results which are in a surprisingly good agreement with
the experimental data. We give also our predicted reduced transition
probabilities within the two approaches, although the corresponding
experimental data are not yet available.Comment: 27pages, 18 figure
The effect of three large Mw¿7.3 subduction earth-quakes (August-November 2012) on volcanic unrest in Central America
¿Was the volcanic eruption triggered by the earthquake?¿ The answer to this question usually
is ¿maybe¿ or ¿a coincidence¿. A region like Central America, is an adequate area to find hints to
answer this question because have the necessary ingredients: the frequent occurrence of large
earthquakes (M5+) and dozens of active volcanoes. This research focuses
on whether the
uncommon occurrence of three large earthquakes in the subduction zone of Central America,
within a time span of ten weeks in 2012, promoted enhanced volcanic activity. The time window
analyzed is from 2000 to 2019, which includes a total of 50 volcanic eruptions with a VEI¿2.
Before the 2012 earthquakes, 22 eruptions occurred.
The Monte Carlo statistical simulation
method allowed to demonstrate that this increase in the number of volcanic eruptions after the
three large earthquakes of 2012 it is not a temporal coincidence. We analyzed the characteristics
of each earthquake and described how they could disturb the volcanic systems. Although Central
America hosts 24 volcanoes with historical eruptions, only 11 of them erupted after the 2012
earthquakes. Why did only these volcanoes erupt? To answer this question, we calculated the
dynamic and static stress in each volcano and the level of volcanic unrest (the change in volcanic
activity beyond background behavior to worrisome levels) prior to the earthquakes. We found
that volcanoes in a unrest stage before the earthquakes but, without experiencing explosive
eruptions before, erupted after receiving the seismic shocks. This fact suggests that the
earthquakes by themselves did not transfer enough energy to generate the volcanic eruptions
when volcanoes were not ready to erupt. However, earthquakes could promote volcanic
eruptions when volcanoes were already at unrest. This research offers a tool for forecasting
volcanic activity when a large earthquake hits a region, if the volcanic activity
is previously
monitored
Increment in the volcanic unrest and number of eruptions after the 2012 large earthquakes sequence in Central America.
Understanding the relationship cause/effect between tectonic earthquakes and volcanic eruptions is a striking topic in Earth Sciences. Volcanoes erupt with variable reaction times as a consequence of the impact of seismic waves (i.e. dynamic stress) and changes in the stress field (i.e. static stress).In2012, three large(Mw≥7.3)subductionearthquakes struck Central Americawithin a period of 10 weeks;subsequently, some volcanoesin the regionerupted a few days after, whileotherstook months or even years to erupt. Here, we show thatthese threeearthquakes contributed to the increase in the number of volcanic eruptionsduring the 7 years that followed these seismic events. We found that onlythosevolcanoes that were already in a critical state ofunrest eventually erupted, which indicates that the earthquakes only prompted the eruptions. Therefore, we recommend the permanent monitoring of active volcanoes toreveal which are more susceptible to culminate into eruption in the aftermath of the next large-magnitude earthquake hits a region.Funding was provided by Japan International Cooperation Agency (JICA) and Istitute Nazionale di Geofisica e Vulcanologia (INGV).Peer reviewe
Author Correction: Increment in the volcanic unrest and number of eruptions after the 2012 large earthquakes sequence in Central America
Correction to: Scientific Reports https://doi.org/10.1038/s41598-021-01725-1, published online 17 November 2021.The original version of this Article contained a repeated error in the Introduction, in Figure 1 and its accompanying legend, in the Results section under the subheading ‘Stress changes caused by the earthquakes’, in the Discussion and conclusions section under the subheading ‘Volcanic eruptions long after the earthquakes’, and in the Supplementary Information file, where the earthquake that occurred on November 7, 2012 was incorrectly mentioned as having occurred on November 11, 2012. The original Fig. 1 and accompanying legend appear below. The original Article and the Supplementary Information file that accompanies the original Article have been corrected.Peer reviewe
Measurement of the production of a W boson in association with a charm quark in pp collisions at √s = 7 TeV with the ATLAS detector
The production of a W boson in association with a single charm quark is studied using 4.6 fb−1 of pp collision data at s√ = 7 TeV collected with the ATLAS detector at the Large Hadron Collider. In events in which a W boson decays to an electron or muon, the charm quark is tagged either by its semileptonic decay to a muon or by the presence of a charmed meson. The integrated and differential cross sections as a function of the pseudorapidity of the lepton from the W-boson decay are measured. Results are compared to the predictions of next-to-leading-order QCD calculations obtained from various parton distribution function parameterisations. The ratio of the strange-to-down sea-quark distributions is determined to be 0.96+0.26−0.30 at Q 2 = 1.9 GeV2, which supports the hypothesis of an SU(3)-symmetric composition of the light-quark sea. Additionally, the cross-section ratio σ(W + +c¯¯)/σ(W − + c) is compared to the predictions obtained using parton distribution function parameterisations with different assumptions about the s−s¯¯¯ quark asymmetry
Molecular techniques and their limitations shape our view of the holobiont
It is now recognised that the biology of almost any organism cannot be fully understood without recognising the existence and potential functional importance of associated microbes. Arguably, the emergence of this holistic viewpoint may never have occurred without the development of a crucial molecular technique, 16S rDNA amplicon sequencing, which allowed microbial communities to be easily profiled across a broad range of contexts. A diverse array of molecular techniques are now used to profile microbial communities, infer their evolutionary histories, visualise them in host tissues, and measure their molecular activity. In this review, we examine each of these categories of measurement and inference with a focus on the questions they make tractable, and the degree to which their capabilities and limitations shape our view of the holobiont
Decreased surfactant phosphatidylcholine synthesis in neonates with congenital diaphragmatic hernia during extracorporeal membrane oxygenation
Purpose: Congenital diaphragmatic hernia (CDH) may result in severe respiratory insufficiency with a high morbidity. The role of a disturbed surfactant metabolism in the pathogenesis of CDH is unclear. We therefore studied endogenous surfactant metabolism in the most severe CDH patients who required extracorporeal membrane oxygenation (ECMO). Methods: Eleven neonates with CDH who required ECMO and ten ventilated neonates without significant lung disease received a 24-h infusion of the stable isotope [U-13C] glucose. The13C-incorporation into palmitic acid in surfactant phosphatidylcholine (PC) isolated from serial tracheal aspirates was measured. Mean PC concentration in epithelial lining fluid (ELF) was measured during the first 4 days of the study. Results: Fractional surfactant PC synthesis was decreased in CDH-ECMO patients compared to controls (2.4 ± 0.33 vs. 8.0 ± 2.4%/day, p = 0.04). The control group had a higher maximal enrichment (0.18 ± 0.03 vs. 0.09 ± 0.02 APE, p = 0.04) and reached this maximal enrichment earlier (46.7 ± 3.0 vs. 69.4 ± 6.6 h, p = 0.004) compared to the CDH-ECMO group, which reflects higher and faster precursor incorporation in the control group. Surfactant PC concentration in ELF was similar in both groups. Conclusion: These results show that CDH patients who require ECMO have a decreased surfactant PC synthesis, which may be part of the pathogenesis of severe pulmonary insufficiency and has a negative impact on weaning from ECMO
Decreased surfactant phosphatidylcholine synthesis in neonates with congenital diaphragmatic hernia during extracorporeal membrane oxygenation
Purpose: Congenital diaphragmatic hernia (CDH) may result in severe respiratory insufficiency with a high morbidity. The role of a disturbed surfactant metabolism in the pathogenesis of CDH is unclear. We therefore studied endogenous surfactant metabolism in the most severe CDH patients who required extracorporeal membrane oxygenation (ECMO). Methods: Eleven neonates with CDH who required ECMO and ten ventilated neonates without significant lung disease received a 24-h infusion of the stable isotope [U-13C] glucose. The13C-incorporation into palmitic acid in surfactant phosphatidylcholine (PC) isolated from serial tracheal aspirates was measured. Mean PC concentration in epithelial lining fluid (ELF) was measured during the first 4 days of the study. Results: Fractional surfactant PC synthesis was decreased in CDH-ECMO patients compared to controls (2.4 ± 0.33 vs. 8.0 ± 2.4%/day, p = 0.04). The control group had a higher maximal enrichment (0.18 ± 0.03 vs. 0.09 ± 0.02 APE, p = 0.04) and reached this maximal enrichment earlier (46.7 ± 3.0 vs. 69.4 ± 6.6 h, p = 0.004) compared to the CDH-ECMO group, which reflects higher and faster precursor incorporation in the control group. Surfactant PC concentration in ELF was similar in both groups. Conclusion: These results show that CDH patients who require ECMO have a decreased surfactant PC synthesis, which may be part of the pathogenesis of severe pulmonary insufficiency and has a negative impact on weaning from ECMO
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