863 research outputs found
Development and assimilate partition in Phaseolus vulgaris as a function of three light levels and three nitrogen doses
O crescimento, a morfologia, a partição de assimilados e a produção de matéria seca foram estudados em Phaseolus vulgaris L. cv. Negrito 897, em condições de campo, sob três níveis de radiação solar (100%, 70% e 30%) e três doses de nitrogênio (zero, 30 e 60 kg de N/ha). A variação da densidade do fluxo radiante e das doses de nitrogênio induziu a planta a modificar a distribuição dos seus fotoassimilados, alterando, consequentemente, seu crescimento e morfologia. A redução da radiação solar e o incremento das doses de nitrogênio promoveram o aumento da altura e da área foliar das plantas. O aumento da razão parte aérea e sistema radicular promovida pelo sombreamento, associado com o incremento das doses de nitrogênio, alterou a partição de assimilados entre os órgãos, resultando em menor proporção de assimilados nas raízes. A ordem sequencial dos drenos metabólicos preferenciais, no entanto, não foi alterada pelos níveis de luz e doses de nitrogênio. A diminuição da radiação solar incidente e das doses de nitrogênio reduziu as taxas de acúmulo de matéria seca na planta toda e em suas partes. Observou-se uma interação significativa entre luz e nitrogênio, em relação ao número de sementes, sendo o maior número alcançado ao nível de 100% de radiação associado com 60 kg de N/ha. A redução da densidade do fluxo radiante promoveu uma diminuição na temperatura da copa das plantas, o que, possivelmente, retardou a senescência de órgãos das plantas sombreadas. Growth, morphology, assimilate partition and dry matter production were studied in Phaseolus vulgaris L. cv. Negrito 897, under field conditions, at three light levels (30%, 70% and 100% of sunlight) and three nitrogen doses (zero, 30 and 60 kg of N/ha). Light flux densities and nitrogen levels induced modifications on the pattern of assimilate distribution, changing the growth and morphology of the plant. Solar energy reduction associated to an increase in nitrogen levels increased stem elongation and leaf area. Shoot/root ratio increased with shading and/or increment of nitrogen levels, changing the normal assimilate partition among organs, and proportionally, less amount of assimilate was exported to roots. However, the preferential sink sequence was not changed by treatments. The rate of dry matter production of the whole plant and its parts decreased with decreasing nitrogen levels and/or shading. A significant interaction between light and nitrogen on one hand and number and dry weight of the seeds on the other was observed. Reduction in light levels decreased the shoot temperature and, probably, delayed the senescence of the plant parts as a consequence of shading.
The effects of nitrogen and light levels on carbohydrate and nitrogen contents in Phaseolus vulgaris
Os efeitos da combinação de três níveis de radiação solar incidente (30%, 70% e 100%) e de três doses de nitrogênio (0, 30 e 60 kg/ha de N) sobre os teores de carboidratos solúveis totais, amido e nitrogênio foram estudados em plantas de Phaseolus vulgaris L. cv. Negrito 897, em condições de campo, durante todo o ciclo da cultura. O aumento da densidade do fluxo luminoso e o das doses de nitrogênio promoveram um incremento nos teores de carboidratos e nitrogênio nos diversos órgãos da planta, sendo os valores máximos observados aos níveis de 70% e 100% de radiação solar e a 30 e 60 kg/ha de N. A 30% de radiação solar incidente e a 30 e 60 kg/ha de N, ocorreu uma redução mais acentuada nos teores dos compostos estudados nas diversas partes da planta, enquanto no tratamento ao qual não se adicionou nitrogênio, independentemente dos níveis de radiação solar, obtiveram-se, também, baixos teores de carboidratos e nitrogênio. Em todos os tratamentos, o acúmulo de nitrogênio total, nas partes da planta, foi proporcional à produção de matéria seca. Observou-se estreita correlação entre o teor de nitrogênio nas folhas, no início da floração, e o número de vagens, na maturação. O maior acúmulo de carboidratos e nitrogênio nas sementes no período de maturidade fisiológica, nos níveis de 70% e 100% de radiação e a 30 e 60 kg/ha de N, deveu-se, principalmente, à fotossíntese e mobilização de assimilados do tecido foliar durante o enchimento de grãos, bem como à mobilização de assimilados armazenados nos caules e raízes durante a fase vegetativa. The effects of three light levels (30%, 70% and 100% of incident sunlight) combined with three nitrogen doses (0, 30 and 60 kg/ha of N) on total soluble carbohydrate, starch and nitrogen contents were studied in Phaseolus vulgaris L. cv. Negrito 897, grown under field conditions, during the entire cycle of the crop. The carbohydrate and nitrogen contents in the plant parts increased with the increase of the light and nitrogen levels. Maxima values are observed under 70% and 100% of sunlight combined with 30 and 60 kg/ha of N. A sharp reduction on carbohydrate and nitrogen contents was observed in all plant parts, caused by the lowest light level associated with high nitrogen levels (30 and 60 kg/ha of N). Lower carbohydrate and nitrogen contents were obtained by no nitrogen addition, independently of light levels. The total nitrogen contents in the plant organs was proportional to dry matter production. A close correlation between leaf nitrogen content at onset of the flowering stage and number of pods at maturation was found. The high accumulation of carbohydrate and nitrogen in the seeds caused by high nitrogen and light levels was due mainly to photosynthesis and assimilate mobilization of leaf tissues during grain filling, as well as mobilization of assimilate stored in stems and roots during the vegetative phase.
Lipolytic Enzymes with Hydrolytic and Esterification Activities Produced by Filamentous Fungi Isolated from Decomposition Leaves in an Aquatic Environment
Microbial lipases are prominent biocatalysts able to catalyze a wide variety of reactions in aqueous and nonaqueous media. In this work, filamentous fungi isolated from leaves decomposed in an aquatic environment were screened for lipase production with hydrolytic activity and esterification. Agar plates with Tween 20 and Rhodamine B were used for selection, while submerged cultures with olive oil were subsequently used to select 38 filamentous fungi. Trichoderma harzianum, Fusarium solani, Trichoderma harzianum F5, and Penicillium sp. F36 were grown in six different culture media. F. solani presented the highest lipase production (2.37 U/mL) with esterification activity of 0.07 U/mL using medium composed of (g.L-1) KH2PO4 1.00, MgSO4 H2O 1.123, and CuSO4 0.06. Supplementation of this culture medium with organic nitrogen sources increased lipase production by 461.3% using tryptone and by 419.4% using yeast extract. Among the vegetable oils from the Amazon region, degummed cotton oil induced lipase production up to 8.14 U/mL. The lipase produced by F. solani F61 has great potential to application in conventional processes and biodiesel production by transesterification of vegetable oils, as well as food industries in the production of fatty acid esters by hydrolysis and esterification. © 2019 D. B. Mendes et al
The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment
The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in
operation since July 2014. This paper describes the second data release from
this phase, and the fourteenth from SDSS overall (making this, Data Release
Fourteen or DR14). This release makes public data taken by SDSS-IV in its first
two years of operation (July 2014-2016). Like all previous SDSS releases, DR14
is cumulative, including the most recent reductions and calibrations of all
data taken by SDSS since the first phase began operations in 2000. New in DR14
is the first public release of data from the extended Baryon Oscillation
Spectroscopic Survey (eBOSS); the first data from the second phase of the
Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2),
including stellar parameter estimates from an innovative data driven machine
learning algorithm known as "The Cannon"; and almost twice as many data cubes
from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous
release (N = 2812 in total). This paper describes the location and format of
the publicly available data from SDSS-IV surveys. We provide references to the
important technical papers describing how these data have been taken (both
targeting and observation details) and processed for scientific use. The SDSS
website (www.sdss.org) has been updated for this release, and provides links to
data downloads, as well as tutorials and examples of data use. SDSS-IV is
planning to continue to collect astronomical data until 2020, and will be
followed by SDSS-V.Comment: SDSS-IV collaboration alphabetical author data release paper. DR14
happened on 31st July 2017. 19 pages, 5 figures. Accepted by ApJS on 28th Nov
2017 (this is the "post-print" and "post-proofs" version; minor corrections
only from v1, and most of errors found in proofs corrected
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
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
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