590 research outputs found
Limited evidence of HCV transmission in stable heterosexual couples from Bahia, Brazil
Subtractive phage display selection from canine visceral leishmaniasis identifies novel epitopes that mimic leishmania infantum antigens with potential serodiagnosis applications
Visceral leishmaniasis (VL) is a zoonotic disease that is endemic to Brazil, where dogs are the main domestic parasite reservoirs,
and the percentages of infected dogs living in regions where canine VL (CVL) is endemic have ranged from 10% to 62%. Despite
technological advances, some problems have been reported with CVL serodiagnosis. The present study describes a sequential
subtractive selection through phage display technology from polyclonal antibodies of negative and positive sera that resulted in
the identification of potential bacteriophage-fused peptides that were highly sensitive and specific to antibodies of CVL. A negative
selection was performed in which phage clones were adhered to purified IgGs from healthy and Trypanosoma cruzi-infected
dogs to eliminate cross-reactive phages. The remaining supernatant nonadhered phages were submitted to positive selection
against IgG from the blood serum of dogs that were infected with Leishmania infantum. Phage clones that adhered to purified
IgGs from the CVL-infected serum samples were selected. Eighteen clones were identified and their reactivities tested by a phage
enzyme-linked immunosorbent assay (phage-ELISA) against the serum samples from infected dogs (n 31) compared to those
from vaccinated dogs (n 21), experimentally infected dogs with cross-reactive parasites (n 23), and healthy controls (n
17). Eight clones presented sensitivity, specificity, and positive and negative predictive values of 100%, and they showed no crossreactivity
with T. cruzi- or Ehrlichia canis-infected dogs or with dogs vaccinated with two different commercial CVL vaccines in
Brazil. Our study identified eight mimotopes of L. infantum antigens with 100% accuracy for CVL serodiagnosis. The use of
these mimotopes by phage-ELISA proved to be an excellent assay that was reproducible, simple, fast, and inexpensive, and it can
be applied in CVL-monitoring programsThis work was supported by grants from the Pró-Reitoria de Pesquisa
of UFMG (supported 03/2013), the Instituto Nacional de Ciência e
Tecnologia em Nano-Biofarmacêutica (INCT Nano-Biofar), Rede
Nanobiotec/Brasil-UFU (CAPES), PRONEX-FAPEMIG (APQ-01019-
09), FAPEMIG (APQ-00496-11 and APQ-00819-12), and CNPq (APQ-
472090/2011-9 and APQ-482976/2012-8). E.A.F.C. and L.R.G. are recipients
of grants from CNPq. M.A.C.-F. is the recipient of a grant from
FAPEMIG/CAPE
Checklist of the dipterofauna (Insecta) from Roraima, Brazil, with special reference to the Brazilian Ecological Station of Maracá
Roraima is a Brazilian state located in the northern portion of the Amazon basin, with few studies regarding its biodiversity. The Ecological Station of Maracá (Brazil, state of Roraima) harbors the third largest Brazilian pluvial island and is composed of a transitional landscape of savanna and Amazon rainforest components. Despite its ecological importance and strategic localization, few studies covered the dipterofauna of this locality. An updated checklist addressing 41 families of true flies (Diptera) occurring in Roraima is presented based on the literature and the specimens collected during a field expedition that occurred in 2015. This checklist brings several improvements such as new records of 165 taxa to the state of Roraima, 29 taxa to Brazil, and 259 morphotypes, mostly likely representing undescribed species
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
Pervasive gaps in Amazonian ecological research
Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4
While the increasing availability of global databases on ecological communities has advanced our knowledge
of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In
the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of
Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus
crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced
environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian
Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by
2050. This means that unless we take immediate action, we will not be able to establish their current status,
much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio
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