4,655 research outputs found
Oxygen and SO2 Consumption Rates in White and Rosé Wines: Relationship with and Effects on Wine Chemical Composition
This Article addresses the study of O2 and SO2 consumption rates of white and rosé wines, their relationship to the initial chemical composition, and their effects on the chemical changes experienced by wine during oxidation. Eight wines were subjected to five consecutive air-saturation cycles. O2 was monitored periodically; SO2, color, and antioxidant indexes were determined after each cycle, and the initial and final compositions of the wines were thoroughly determined. Wines consumed oxygen at progressively decreasing rates. In the last cycles, after a strong decrease, consistent increases of oxygen levels were seen. Oxygen consumption rates were satisfactorily modeled, being proportional to wine copper, quercetin, and kaempherol contents and negatively proportional to cinnamic acids. SO2 consumption rates were highly diverse between wines and were positively related to free SO2, Mn, and pH, among others. In the last saturations, SO2 consumption took place regardless of O2 consumption, implying that SO2 should reduce chemical species oxidized in previous saturations. Some volatile phenols seem to be the end point of radical-mediated oxidation of polyphenols taking place preferably in the first saturation
Matter profile effect in neutrino factory
We point out that the matter profile effect --- the effect of matter density
fluctuation on the baseline --- is very important to estimate the parameters in
a neutrino factory with a very long baseline. To make it clear, we propose the
method of the Fourier series expansion of the matter profile. By using this
method, we can take account of both the matter profile effect and its
ambiguity. For very long baseline experiment, such as L=7332km, in the analysis
of the oscillation phenomena we need to introduce a new parameter ---
the Fourier coefficient of the matter profile --- as a theoretical parameter to
deal with the matter profile effects.Comment: 21 pages, 15 figure
Critical sets of nonlinear Sturm-Liouville operators of Ambrosetti-Prodi type
The critical set C of the operator F:H^2_D([0,pi]) -> L^2([0,pi]) defined by
F(u)=-u''+f(u) is studied. Here X:=H^2_D([0,pi]) stands for the set of
functions that satisfy the Dirichlet boundary conditions and whose derivatives
are in L^2([0,pi]). For generic nonlinearities f, C=\cup C_k decomposes into
manifolds of codimension 1 in X. If f''0, the set C_j is shown to be
non-empty if, and only if, -j^2 (the j-th eigenvalue of u -> u'') is in the
range of f'. The critical components C_k are (topological) hyperplanes.Comment: 6 pages, no figure
Seletividade de agroquímicos ao parasitóide de ovos Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) em condições de laboratório.
Recent Advances in Chromospheric and Coronal Polarization Diagnostics
I review some recent advances in methods to diagnose polarized radiation with
which we may hope to explore the magnetism of the solar chromosphere and
corona. These methods are based on the remarkable signatures that the
radiatively induced quantum coherences produce in the emergent spectral line
polarization and on the joint action of the Hanle and Zeeman effects. Some
applications to spicules, prominences, active region filaments, emerging flux
regions and the quiet chromosphere are discussed.Comment: Review paper to appear in "Magnetic Coupling between the Interior and
the Atmosphere of the Sun", eds. S. S. Hasan and R. J. Rutten, Astrophysics
and Space Science Proceedings, Springer-Verlag, 200
A near-IR line of Mn I as a diagnostic tool of the average magnetic energy in the solar photosphere
We report on spectropolarimetric observations of a near-IR line of Mn I
located at 15262.702 A whose intensity and polarization profiles are very
sensitive to the presence of hyperfine structure. A theoretical investigation
of the magnetic sensitivity of this line to the magnetic field uncovers several
interesting properties. The most important one is that the presence of strong
Paschen-Back perturbations due to the hyperfine structure produces an intensity
line profile whose shape changes according to the absolute value of the
magnetic field strength. A line ratio technique is developed from the intrinsic
variations of the line profile. This line ratio technique is applied to
spectropolarimetric observations of the quiet solar photosphere in order to
explore the probability distribution function of the magnetic field strength.
Particular attention is given to the quietest area of the observed field of
view, which was encircled by an enhanced network region. A detailed theoretical
investigation shows that the inferred distribution yields information on the
average magnetic field strength and the spatial scale at which the magnetic
field is organized. A first estimation gives ~250 G for the mean field strength
and a tentative value of ~0.45" for the spatial scale at which the observed
magnetic field is horizontally organized.Comment: 42 pages, 17 figures, accepted for publication in the Astrophysical
Journal. Figures 1 and 9 are in JPG forma
The Lhcb protein and xanthophyll composition of the light harvesting antenna controls the ΔpH-dependency of non-photochemical quenching in Arabidopsis thaliana
AbstractNonphotochemical quenching (NPQ) is the photoprotective dissipation of energy in photosynthetic membranes. The hypothesis that the ΔpH-dependent component of NPQ (qE) component of non-photochemical quenching is controlled allosterically by the xanthophyll cycle has been tested using Arabidopsis mutants with different xanthophyll content and composition of Lhcb proteins. The titration curves of qE against ΔpH were different in chloroplasts containing zeaxanthin or violaxanthin, proving their roles as allosteric activator and inhibitor, respectively. The curves differed in mutants deficient in lutein and specific Lhcb proteins. The results show that qE is determined by xanthophyll occupancy and the structural interactions within the antenna that govern allostericity
Seletividade de agrotóxicos à Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae).
Trichogramma pretiosum é um agente de controle biológico eficaz para utilização em programas de manejo de Pseudoplusia includens e Anticarsia gemmatalis em diferentes áreas geográficas e condições climáticas onde a soja é cultivada. No entanto, atualmente, a utilização de agrotóxicos ainda é necessária para o controle de pragas nessa cultura e por isso é preciso selecionar aqueles com menor impacto negativo aos agentes de controle biológico. Portanto, objetivando selecionar os agrotóxicos mais seletivos ao T. pretiosum, 19 inseticidas, sete herbicidas e 10 fungicidas foram avaliados em pupas e adultos de T. pretiosum em condições de laboratório seguindo os protocolos internacionais padronizados pela International Organization for Biological Control (IOBC). Em geral, os insecticidas foram mais tóxicos para o parasitoide quando comparados com os fungicidas e herbicidas. Entre os inseticidas, os produtos do grupo dos reguladores de crescimento de insetos e os vírus da poliedrose nuclear (baculovírus) foram inócuos, enquanto os do grupo dos piretróides, organofosforados e carbamatos foram classificados como nocivos. Entre os herbicidas o paraquate foi o mais prejudicial e o 2,4-D o mais inócuo, enquanto os demais foram ligeiramente ou moderadamente nocivos. Todos os fungicidas testados foram classificados como seletivos ou levemente nocivos para pupa e adultos do parasitoide. Por conseguinte, tendo essa diferença observada em relação aos efeitos colaterais, os produtos menos nocivos devem ser escolhidos, sempre que possível para serem utilizados no MIP-Soja. Ainda, a seletividade de agrotóxicos mostrou-se ser um critério importante na escolha do melhor agrotóxicos para ser usado na soja, visando a sustentabilidade desta cultura
- …