439 research outputs found
Thermal and chemical treatments of common bean seeds: Efficiency in Curtobacterium flaccumfaciens pv. flaccumfaciens eradication and effects on the physiological quality of seeds
Foram testados o efeito da termo e quimioterapia na erradicação de Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff) e sobre a qualidade fisiológica de sementes de feijoeiro (Phaseolus vulgaris) cv. Pérola. Os tempos (30 min, 1 e 2 h)
de embebição em água e em soluções de AGRIMAICIN 500 (sulfato de cobre, 500 g + oxitetraciclina, 30 g/kg do produto)
nas concentrações de 5 e 10 g/L de água; o calor seco (60 e 70 ºC por 1, 2, 3, 6 e 12 h); e calor a 60 ºC/3 h em sementes
previamente embebidas em água por 30 min, 1 e 2 h foram aplicados. Sementes embebidas em água por mais de 1 h tiveram
o vigor afetado. Embebição das sementes (30 min, 1 e 2 h) em solução com 10 g de AGRIMAICIN 500/L de água afetou
o comprimento das radículas e dos caulículos, enquanto que a germinação só foi afetada com 2 h. O tratamento eliminou a
bactéria de sementes naturalmente infectadas, no entanto, em sementes inoculadas (108 ufc/mL) o tratamento não foi efetivo.
Exposição ao calor seco (60 e 70 ºC) por mais de 3 h reduziu significativamente o vigor das sementes, mas não eliminou a
bactéria. Embebição das sementes em água por 30 min e 1 h + 60 ºC/3 h afetou o comprimento dos caulículos e das radículas,
mas não eliminou a bactéria. Embebição das sementes por duas horas em água + 60 ºC/3 h reduziu significativamente a
germinação e o vigor; reduziu, ainda, significativamente o número de células de Cff em sementes inoculadas e eliminou a
bactéria em sementes naturalmente infectadas. _________________________________________________________________________________ ABSTRACTThe effect of thermo and chemotherapy on the eradication of Curtobacterium flaccumfaciens pv. flaccumfaciens
(Cff) and on the physiological quality of seeds of common bean (Phaseolus vulgaris) cv. Pérola were tested. Soaking times
(30 min, 1 and 2 h) in water and in AGRIMAICIN 500 solutions (copper sulphate, 500 g + oxytetracyclin, 30 g/kg of the
product) in concentrations of 5 and 10 g/L of water; dry heat (60 and 70 ºC for 1, 2, 3, 6 and 12 h); and heat of 60 ºC/3 h
on previously soaked seeds for 30 min, 1 and 2 h were tested. The vigor of seeds soaked in water for more than 1 h was
affected. Soaking the seeds (30 min, 1 and 2 h) in solution with 10 g of AGRIMAICIN 500/L of water affected the length
of the rootlet and the stem, whereas germination was affected only with 2 h. The treatment eliminated the bacterium from
naturally infected seeds; however it was not effective in inoculated seeds (108 ufc/mL). Dry heat (60 and 70 ºC) for more
than 3 h reduced significantly the vigor of the seeds and did not eliminate the bacterium. Soaking the seeds for 30 min and 1
h + 60 ºC/3 h affected the length of the stem and rootlet but did not eliminate the bacterium. Two hours of soaking the seeds
in water ± 60 ºC/3 h reduced significantly the germination and the vigor; it also reduced significantly the Cff in inoculated
seeds, whereas it eliminated the bacterium in naturally infected ones
Relationship between nitrogen sources, germination and vigor of soybean seeds
This research was conducted in two experimental areas; the first had been under cultivation with Bradyrhizobium japonicum anually inoculated for several years and the second was cultivated with sugarcane for many years receiving only mineral fertilization. Mineral nitrogen (urea and ammonium) effect was compared with the effects of inoculant treatments (liquid and peat carriers) on plant development, yield and seed quality. After harvesting, seeds were stored under normal environmental conditions and tested periodically. Germination, accelerated aging, electrical conductivity and seedling emergence tests showed that seeds coming from the area where inoculation was practiced have better quality. Best plant performance regarding plant height at different growth stages and yield was also found in this area. Among the nitrogen sources studied, best results were obtained when peat was the inoculant carrier.A pesquisa foi conduzida em duas áreas experimentais do Departamento de Agricultura, ESALQ/USP. A primeira, cultivada com soja anualmente inoculada com Bradyrhizobium japonicum, durante vários anos e, a segunda, anteriormente cultivada com cana-de-açúcar, recebendo apenas adubação mineral. Os efeitos da aplicação de uréia e de sulfato de amonio foram comparados com os da inoculação de sementes, utilizando-se, produtos veiculados em turfa ou em meio líquido; avaliaram-se o desenvolvimento das plantas, a produção final e a qualidade das sementes (testes de germinação e de vigor) logo após a colheita e durante o armazenamento. Os resultados permitiram constatar o melhor desempenho fisiológico das sementes produzidas em área anteriormente cultivada com soja, o mesmo ocorrendo com o desenvolvimento inicial das plantas. Dentre as fontes de nitrogênio avaliadas, a utilização de inoculante veiculado em turfa se mostrou mais favorável
Photoacoustic Characterization Of Photovoltaic Cells
The photoacoustic characterization of Si solar-cell samples having distinct internal resistances, both at low and high modulation frequencies, yielded results significantly different from each other. For large samples with very small internal resistances (∼0.1 Ω), the additional contribution of the current dissipation near short-circuit conditions yielded results similar to those obtained with photothermal radiometry or the pyroelectric detection. For small samples, the results for the conversion efficiency, both at low and high modulation frequencies, are similar to ones obtained from the conventional electrical measurements.61115176517
A home monitoring program including real-time wireless home spirometry in idiopathic pulmonary fibrosis
In idiopathic pulmonary fibrosis (IPF), home monitoring experiences are limited, not yet real-time available nor implemented in daily care. We evaluated feasibility and potential barriers of a new home monitoring program with real-time wireless home spirometry in IPF. Ten patients with IPF were asked to test this home monitoring program, including daily home spirometry, for four weeks. Measurements of home and hospital spirometry showed good agreement. All patients considered real-time wireless spirometry useful and highly feasible. Both patients and researchers suggested relatively easy solutions for the identified potential barriers regarding real-time home monitoring in IPF
Small Fermi surface in the one-dimensional Kondo lattice model
We study the one-dimensional Kondo lattice model through the density matrix
renormalization group (DMRG). Our results for the spin correlation function
indicate the presence of a small Fermi surface in large portions of the phase
diagram, in contrast to some previous studies that used the same technique. We
argue that the discrepancy is due to the open boundary conditions, which
introduce strong charge perturbations that strongly affect the spin Friedel
oscillations.Comment: 5 pages, 7 figure
High-resolution x-ray study of the nematic - smectic-A and smectic-A - smectic-C transitions in 8barS5-aerosil gels
The effects of dispersed aerosil nanoparticles on two of the phase
transitions of the thermotropic liquid crystal material
4-n-pentylphenylthiol-4'-n-octyloxybenzoate 8barS5 have been studied using
high-resolution x-ray diffraction techniques. The aerosils hydrogen bond
together to form a gel which imposes a weak quenched disorder on the liquid
crystal. The smectic-A fluctuations are well characterized by a two-component
line shape representing thermal and random-field contributions. An elaboration
on this line shape is required to describe the fluctuations in the smectic-C
phase; specifically the effect of the tilt on the wave-vector dependence of the
thermal fluctuations must be explicitly taken into account. Both the magnitude
and the temperature dependence of the smectic-C tilt order parameter are
observed to be unaffected by the disorder. This may be a consequence of the
large bare smectic correlation length in the direction of modulation for this
transition. These results show that the understanding developed for the nematic
to smectic-A transition for octylcyanobiphenyl (8CB) and octyloxycyanobiphenyl
(8OCB) liquid crystals with quenched disorder can be extended to quite
different materials and transitions.Comment: 7 pages, 8 figure
Regularization of point vortices for the Euler equation in dimension two
In this paper, we construct stationary classical solutions of the
incompressible Euler equation approximating singular stationary solutions of
this equation.
This procedure is carried out by constructing solutions to the following
elliptic problem [ -\ep^2 \Delta
u=(u-q-\frac{\kappa}{2\pi}\ln\frac{1}{\ep})_+^p, \quad & x\in\Omega, u=0, \quad
& x\in\partial\Omega, ] where , is a bounded
domain, is a harmonic function.
We showed that if is simply-connected smooth domain, then for any
given non-degenerate critical point of Kirchhoff-Routh function
with the same strength , there is a
stationary classical solution approximating stationary points vortex
solution of incompressible Euler equations with vorticity .
Existence and asymptotic behavior of single point non-vanishing vortex
solutions were studied by D. Smets and J. Van Schaftingen (2010).Comment: 32page
Disorder-to-order transition in the magnetic and electronic properties of URh_2Ge_2
We present a study of annealing effects on the physical properties of
tetragonal single--crystalline URh_2Ge_2. This system, which in as-grown form
was recently established as the first metallic 3D random-bond heavy-fermion
spin glass, is transformed by an annealing treatment into a long-range
antiferromagnetically (AFM) ordered heavy-fermion compound. The transport
properties, which in the as-grown material were dominated by the structural
disorder, exhibit in the annealed material signs of typical metallic behavior
along the crystallographic a axis. From our study URh_2Ge_2 emerges as
exemplary material highlighting the role and relevance of structural disorder
for the properties of strongly correlated electron systems. We discuss the link
between the magnetic and electronic behavior and how they are affected by the
structural disorder.Comment: Phys. Rev. B, in print (scheduled 1 Mar 2000
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