2,050 research outputs found
La técnica de precoloración de Walker para evaluar Plasmodium vivax Grassi y Plasmodium malariao Laveran en comunidades asháninkas en Satipo (Junín, Perú)
The precoloration technique of Walker was assayed in comparation with the classic Giemsa technique as a differential method to Plasmodium vivax and Plasmodium malariae, in 208 blood samples of seven Ashaninka communities from Rio Tambo district, Satipo, Junin, Peru. Density of parasites by crossing system (+) and by parasites/mL were higher with precoloration of Walker. The prevalence of the parasites was to P. vivax (24,52%) and P. malariae (0,48%) of all samples assayed. Of the seven communities evaluated from Rio Tambo district: Puerto Ocopa, Unión Puerto Ashaninka and Shimavenzo communities showed the highest prevalence of infection with 42,42%, 27,27% y 27,27% respectively. The ages between 0 to 10 and 41-50 years showed the highest prevalence of infection with 31,30% and 40% respectively. The prevalence of infection was independent with the sex. Density of parasites/mL with both techniques were higher in Puerto Prado community; but statistically independent with age and sex. The advantage of precoloration technique of Walker was investigated and some factors that would influence variations in the prevalence of infection and density of parasites of plasmodia assayed dependent on what communities were sampled, age and sex.Se evaluó la técnica de precoloración de Walker en comparación con la técnica de Giemsa clásica como método de diferenciación para las especies de Plasmodium vivax y Plasmodium malaria, en 208 muestras de sangre de siete comunidades Asháninkas en el distrito de Río Tambo, Satipo, Junín, Perú. La densidad parasitaria por el sistema de cruces (+) y por parásitos/mL fue mayor en la técnica de precoloración de Walker. La prevalencia del parásito en el total de muestras evaluadas fue: P vivax (24,52%) y P. malariae (0,48%). De las siete comunidades evaluadas en el distrito de Río Tambo: Puerto Ocopa, Unión Puerto Asháninka y Shimavenzo presentaron la mayor prevalencia de infección con 42,42%, 27,27% y 27,27% respectivamente. Las edades de 0 a 10 años y 41-50 años presentaron la mayor prevalencia de infección con 31,30% y 40% respectivamente. La prevalencia de infección por plasmodio fue independiente del sexo. La densidad de parásitos/mL por ambas técnicas de diferenciación, fue mayor en la comunidad Puerto Prado, pero estadísticamente independiente de los grupos etáreos y el sexo. Se analizan las ventajas de la técnica de la precoloración de Walker y algunos factores que influirían en las variaciones en la prevalencia de infección y densidad parasitaria de los plasmodios en dependencia de las comunidades evaluadas, grupos etáreos y el sexo
Support effects on NiO-based catalysts for the oxidative dehydrogenation (ODH) of ethane
[EN] We report on the effect of NiO-support interactions on the chemical nature of Ni species in a series of supported NiO catalysts for the ODH of ethane. SiO2, TiO2-anatase, a high surface area TiO2 and a porous clay hetero-structure (PCH) with TiO2 and SiO2 pillars were used as supports, which led to a selectivity to ethylene in the range 30-90% over supported NiO catalysts. The catalysts were characterized by means of XRD, N-2-Adsorption, H-2-TPR, XPS and in situ (under H-2 reductive atmosphere) and ex situ XAS spectroscopy. The catalytic performance of supported materials is discussed in terms of their reducibility and specific reduction kinetics, but also taking into account the specific chemical nature of Ni species on each catalyst. The influence of the particle size and the presence of Ni and O vacancies on the catalytic performance in the ODH of ethane is inferred.Authors would like to thank the DGICYT in Spain CTQ2015-68951-C3-1-R, CTQ2015-68951-C3-3-R, CTQ2012-37925-C03-2 and ENE2017-88818-C2-1-R. Also authors want to acknowledge the ALBA Synchrotron Light Source (Project ID: 2015021258 at CLAESS beamline). Authors from ITQ thank Project SEV-2016-0683 for financial support. D. D. also thanks MINECO and Severo Ochoa Excellence Program for his fellowship (SVP-2014-068669). Authors from UV thank the University of Valencia (UV-INV-AE16-484416 project) and MINECO (MAT2017-84118-C2-1-R project) for funding.Delgado-Muñoz, D.; Sanchís, R.; Cecilia, JA.; Rodríguez-Castellón, E.; Caballero, A.; Solsona, B.; López Nieto, JM. (2019). Support effects on NiO-based catalysts for the oxidative dehydrogenation
(ODH) of ethane. Catalysis Today. 333:10-16. https://doi.org/10.1016/j.cattod.2018.07.010S101633
Co on Fe3O4(001): Towards precise control of surface properties
A novel approach to incorporate cobalt atoms into a magnetite single crystal is demonstrated by a combination of x-ray spectro-microscopy, low-energy electron diffraction, and density-functional theory calculations. Co is deposited at room temperature on the reconstructed magnetite (001) surface filling first the subsurface octahedral vacancies and then occupying adatom sites on the surface. Progressive annealing treatments at temperatures up to 733 K diffuse the Co atoms into deeper crystal positions, mainly into octahedral ones with a marked inversion level. The oxidation state, coordination, and magnetic moments of the cobalt atoms are followed from their adsorption to their final incorporation into the bulk, mostly as octahedral Co. This precise control of the near-surface Co atoms location opens up the way to accurately tune the surface physical and magnetic properties of mixed spinel oxides.Peer Reviewe
Monitoring of hepatitis E virus in zoo animals from Spain, 2007–2021
Hepatitis E virus (HEV, family Hepeviridae) is an important emerging and zoonotic pathogen. In recent decades, the number of human cases of zoonotic hepatitis E has increased considerably in industrialized countries and HEV has been detected in an expanding range of mammal species. Although domestic pigs and wild boar are considered the main reservoirs of zoonotic HEV genotypes, the role of other susceptible animals in the epidemiology of the virus is still poorly understood. A large-scale, long-term study was carried out (1) to assess HEV exposure in captive zoo animals in Spain and (2) to determine the dynamics of seropositivity in individuals that were sampled longitudinally during the study period. Between 2007 and 2021, serum samples from 425 zoo animals belonging to 109 animal species (including artiodactyls, carnivores, perissodactyls, proboscideans and rodents) were collected from 11 different zoological parks in Spain. Forty-six of these animals at seven of these zoos were also longitudinally sampled. Anti-HEV antibodies were detected in 36 (8.5%; 95% CI: 5.8–11.1) of 425 sampled zoo animals. Specific antibodies against HEV-3 and HEV-C1 antigens were confirmed in ELISA-positive animals using western blot assay. Two of 46 longitudinally surveyed animals seroconverted during the study period. Seropositivity was significantly higher in carnivores and perissodactyls than in artiodactyls, and also during the period 2012–2016 compared with 2007–2011. HEV RNA was not detected in any of the 262 animals that could be tested by RT-PCR. To the best of the author's knowledge, this is the first large-scale, long-term surveillance on HEV in different orders of zoo mammals. Our results indicate exposure to HEV-3 and HEV-C1 in zoo animals in Spain and confirm a widespread but not homogeneous spatiotemporal circulation of HEV in captive species in this country. Further studies are required to determine the role of zoo species, particularly carnivores and perissodactyls, in the epidemiology of HEV and to clarify the origins of infection in zoological parks
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory
The Auger Engineering Radio Array (AERA) is part of the Pierre Auger
Observatory and is used to detect the radio emission of cosmic-ray air showers.
These observations are compared to the data of the surface detector stations of
the Observatory, which provide well-calibrated information on the cosmic-ray
energies and arrival directions. The response of the radio stations in the 30
to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of
the incoming electric field. For the latter, the energy deposit per area is
determined from the radio pulses at each observer position and is interpolated
using a two-dimensional function that takes into account signal asymmetries due
to interference between the geomagnetic and charge-excess emission components.
The spatial integral over the signal distribution gives a direct measurement of
the energy transferred from the primary cosmic ray into radio emission in the
AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air
shower arriving perpendicularly to the geomagnetic field. This radiation energy
-- corrected for geometrical effects -- is used as a cosmic-ray energy
estimator. Performing an absolute energy calibration against the
surface-detector information, we observe that this radio-energy estimator
scales quadratically with the cosmic-ray energy as expected for coherent
emission. We find an energy resolution of the radio reconstruction of 22% for
the data set and 17% for a high-quality subset containing only events with at
least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO
Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy
We measure the energy emitted by extensive air showers in the form of radio
emission in the frequency range from 30 to 80 MHz. Exploiting the accurate
energy scale of the Pierre Auger Observatory, we obtain a radiation energy of
15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV
arriving perpendicularly to a geomagnetic field of 0.24 G, scaling
quadratically with the cosmic-ray energy. A comparison with predictions from
state-of-the-art first-principle calculations shows agreement with our
measurement. The radiation energy provides direct access to the calorimetric
energy in the electromagnetic cascade of extensive air showers. Comparison with
our result thus allows the direct calibration of any cosmic-ray radio detector
against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI.
Supplemental material in the ancillary file
CMS physics technical design report : Addendum on high density QCD with heavy ions
Peer reviewe
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