1,247 research outputs found
Preliminary study on the potential use of RPA images to quantify the influence of the defoliation after coffee harvesting to its yield
Received: January 24th, 2023 ; Accepted: May 22nd, 2023 ; Published: September 18th, 2023 ; Correspondence: [email protected] is an agricultural commodity with global commercial importance capable of
impacting the production chain. The quantification of defoliation at harvest is important for
monitoring crop yield because defoliation is one of the main types of damage caused by this
agricultural operation in coffee crops. Thus, the objective of this study was to evaluate the
relationship between yield and defoliation obtained in the field and obtained through remotely
piloted aircraft (RPA) images. The experiment was conducted in a coffee plantation belonging to
the Federal University of Lavras (UFLA), Lavras, Minas Gerais state, Brazil. An RPA with a
rotary wing containing a multispectral camera was used in autonomous flight mode with a height
of 30 m, an image overlap of 80%, and a speed of 3 m s-1
. The images were collected before and
after the 2020 and 2021 harvest, defoliation data obtained in the field were measured in 2020 and
2021, and the yield was measured from 2019 to 2021. Image processing was performed in the
software PhotoScan, postimage processing was performed in QGIS, and statistical analyses were
performed using the software R. With the processing of the images in 2020, the crop showed
reductions of 17.3% and 18.4% in leaf area and volume, respectively, after harvest. In 2021, the
crop showed reductions of 12.8% and 9.8% in leaf area and volume, respectively, after harvest.
The leaf area and leaf volume of the coffee plantation after harvest could be quantified by means
of images obtained by RPA, which allowed the observation of the loss of area and volume of the
coffee plantation. Furthermore, it was possible to analyse the interactions between field data and
the yield of the same harvest year, which were directly proportional, and the interaction of image
data from one year with the previous yield, which were inversely proportional. In the year 2020,
there was a reduction of 17.3% in leaf area after harvest, and a reduction of 18.4% in leaf volume
after harvest in the plots under study.In the processing carried out in 2021, there was a 12.8%
reduction in leaf area after harvest, and a 9.8% decrease in leaf volume after harvest in the plots
under study
Antibiotic resistance genes detected in the marine sponge <i>Petromica citrina</i> from Brazilian coast
Although antibiotic-resistant pathogens pose a significant threat to human health, the environmental reservoirs of the resistance determinants are still poorly understood. This study reports the detection of resistance genes (ermB, mecA, mupA, qnrA, qnrB and tetL) to antibiotics among certain culturable and unculturable bacteria associated with the marine sponge Petromica citrina. The antimicrobial activities elicited by P. citrina and its associated bacteria are also described. The results indicate that the marine environment could play an important role in the development of antibiotic resistance and the dissemination of resistance genes among bacteria
Draft genome sequences of photobacterium damselae subsp. piscicida SNW-8.1 and PP3, two fish-isolated strains containing a type III secretion system
Here, we report the draft genome sequences of two strains of the fishpathogenPhotobacterium damselaesubsp.piscicida, isolated fromSalmo salar(SNW-8.1) andSeriola quinqueradiata(PP3). The identification of a type III secretion systemin the two genomes furthers our understanding of the pathobiology of this sub-speciesThis work has been supported by grant AGL2016-79738-R (AEI/FEDER, EU) from the Agencia Estatal de Investigación (AEI) of Spain and cofunded by the FEDER Program from the European Union. The support of Xunta de Galicia (Spain) with grant ED431C 2018/18 is also acknowledgedS
Magnetic and pair correlations of the Hubbard model with next-nearest-neighbor hopping
A combination of analytical approaches and quantum Monte Carlo simulations is
used to study both magnetic and pairing correlations for a version of the
Hubbard model that includes second-neighbor hopping as a
model for high-temperature superconductors. Magnetic properties are analyzed
using the Two-Particle Self-Consistent approach. The maximum in magnetic
susceptibility as a function of doping appears both at finite
and at but for two totally different physical reasons. When
, it is induced by antiferromagnetic correlations while at
it is a band structure effect amplified by interactions.
Finally, pairing fluctuations are compared with -matrix results to
disentangle the effects of van Hove singularity and of nesting on
superconducting correlations. The addition of antiferromagnetic fluctuations
increases slightly the -wave superconducting correlations despite the
presence of a van Hove singularity which tends to decrease them in the
repulsive model. Some aspects of the phase diagram and some subtleties of
finite-size scaling in Monte Carlo simulations, such as inverted finite-size
dependence, are also discussed.Comment: Revtex, 8 pages + 15 uuencoded postcript figure
Análise geoambiental do riacho Santa Bárbara Zona urbana – Parnarama-Maranhão
Análise geoambiental do riacho Santa BárbaraZona urbana – Parnarama-Maranhã
Superconductivity in the Nb2SnC compound
Nb2SnC is a member of the large family of lamellar materials that crystallize
in the hexagonal structure with space group P63/mmc which are isomorphs with
Cr2AlC, also named H-phase. In spite of the great number of compounds which
belong to this family, the superconductivity has been reported only for two
cases: Mo2GaC and Nb2SC. In this work we show that superconductivity can be
observed in Nb2SnC depending on the synthesis method used. The quality of the
superconductor is strongly dependent of the synthesis method and the optimal
results were reached for samples synthesized at 2.5 GPa and 523 +/- 50oC. This
sample showed a critical temperature close to 7.8K, revealed from magnetization
and transport measurement, the highest critical temperature reported up to now
for an H-phase.Comment: paper with 12 pages and 4 figure
Chemical similarity among domesticated and wild genotypes of peanut based on n-alkanes profiles
From cosmic deceleration to acceleration: new constraints from SN Ia and BAO/CMB
We use type Ia supernovae (SN Ia) data in combination with recent baryonic
acoustic oscillations (BAO) and cosmic microwave background (CMB) observations
to constrain a kink-like parametrization of the deceleration parameter ().
This -parametrization can be written in terms of the initial () and
present () values of the deceleration parameter, the redshift of the
cosmic transition from deceleration to acceleration () and the redshift
width of such transition (). By assuming a flat space geometry,
and adopting a likelihood approach to deal with the SN Ia data we obtain, at
the 68% confidence level (C.L.), that: ,
and when we combine
BAO/CMB observations with SN Ia data processed with the MLCS2k2 light-curve
fitter. When in this combination we use the SALT2 fitter we get instead, at the
same C.L.: , and
. Our results indicate, with a quite general and
model independent approach, that MLCS2k2 favors Dvali-Gabadadze-Porrati-like
cosmological models, while SALT2 favors CDM-like ones. Progress in
determining the transition redshift and/or the present value of the
deceleration parameter depends crucially on solving the issue of the difference
obtained when using these two light-curve fitters.Comment: 25 pages, 9 figure
Semi-automatic segmentation of skin lesions based on superpixels and hybrid texture information
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