1,449 research outputs found
Diversification processes between monogenoids (Dactylogyridae) and their marine catfish (Siluriformes: Ariidae) from the Atlantic coast of South America
Due to their high specificity, monogenoids from fish provide an interesting model to study historical associations of hosts and parasites. High agreement between host and parasite phylogeny is often interpreted as evidence of cospeciation. However, cophylogenetic signal may also arise from other, either adaptive or non-adaptive, processes. We applied the recently developed Cophylospace Framework to better understand the evolutionary relationship between monogenoids and marine catfish from the Atlantic coast of South America. The associations between 12 marine catfish and 10 monogenoid species were assessed. Molecular data of host and parasite species were used for phylogenetic reconstruction. We used anchor morphology based on Procrustes coordinates to evaluate whether closely related hosts are associated with morphologically similar parasites. To assess the association between parasite phylogeny and host morphology, we produced a distance matrix based on morphological characters of catfishes. Agreement between phylogenies and between phylogeny and morphology was measured using Procrustes R2 computed with PACo. The parasite phylogeny obtained in this study represents the first complete phylogenetic hypothesis of monogenoids parasitizing ariids from South America. The Cophylospace analysis suggested that phylogenetic and morphological distance of monogenoids contributes similarly to explain the pattern of host-parasite associations, whereas parasite phylogeny is more strongly associated with the morphological traits of the hosts than with host phylogeny. This evidence suggests that cospeciation is not a major force accounting for diversification in the monogenoids studied. Rather host morphological traits seem to be a more important driver, which conforms with evidence from other host‒monogenoid systems
Copper and lead residues in olives after olive tree treatments with three different copper formulations.
Validation of a method to quantify copper and other metals in olive fruit by ETAAS. Application to the residual metal control after olive tree treatments with different copper formulations
An electrothermal atomization atomic absorption spectrometry method was validated to quantify residues of copper, aluminum, cadmium, chromium, iron, lead, and nickel in olive fruit. The linearity
ranges under the optimized conditions were 0.19-20.0, 1.11-50.0, 0.02-2.0, 0.15-20.0, 0.80-
20.0, 0.35-50.0, and 0.60-50.0 Ăg/L, respectively. The limits of quantification were, expressed in
nanograms per gram of dry weight, 12.6, 74.0, 1.34, 10.0, 53.4, 23.4, and 40.0, respectively. For all
of the metals the precision of the instrumental method was <6.3% and that of the analytical method
was always <10%, except for aluminum, for which the precision was 12%. The accuracy of the method
was evaluated according to the standard additions method, the recoveries being >90% for all of the
added concentrations. An interference study was also carried out in a simulated matrix, and it was
verified that the deviations of the expected values were <6% for all of the metals. The method was
applied to the monitoring of the residues of the referred metals in olive fruits collected from trees
pulverized with three different copper formulations available on the market to control fungal diseases
Mechanisms of Spontaneous Current Generation in an Inhomogeneous d-Wave Superconductor
A boundary between two d-wave superconductors or an s-wave and a d-wave
superconductor generally breaks time-reversal symmetry and can generate
spontaneous currents due to proximity effect. On the other hand, surfaces and
interfaces in d-wave superconductors can produce localized current-carrying
states by supporting the T-breaking combination of dominant and subdominant
order parameters. We investigate spontaneous currents in the presence of both
mechanisms and show that at low temperature, counter-intuitively, the
subdominant coupling decreases the amplitude of the spontaneous current due to
proximity effect. Superscreening of spontaneous currents is demonstrated to be
present in any d-d (but not s-d) junction and surface with d+id' order
parameter symmetry. We show that this supercreening is the result of
contributions from the local magnetic moment of the condensate to the
spontaneous current.Comment: 4 pages, 5 figures, RevTe
Metal composition of table olives from the portuguese market.
Olive tree (Olea europaea L.) is one of the most important fruit trees in the Mediterranean countries. Their products, olive oil and also table olives, are important components of the Mediterranean diet and are largely consumed in the world. Table olives are well-known sources of compounds with important biological properties. The preparation of table olives follows three main trades, namely green or Spanish-style olives (Green Olives in Brine - GOB), black ripe or Californian-style olives (Black Ripe Olives), and naturally fermented olives (Direct Brined Olives – DBO). Heavy metals can be present in olive fruits for several reasons: endogenous, depending on the mineral constitution of the soils where the olive trees are located, or exogenous, resulting from the air pollution, contamination by phyto-chemical products and during technological processing. Besides the toxicological characteristics of these elements, the presence of transition metals in these fat matrices can negatively influence the organoleptic and nutritional properties as well as the shelf life of the products
Antioxidant activity and phenolic contents of Olea europaea L. leaves sprayed with different copper formulations
Olive trees (Olea europaea L. Cv. Cobranc¸osa) from the northeast of Portugal were sprayed with three different copper formulations
[bordeaux mixture (copper sulphate + calcium hydroxide - 20% Cu), copper hydroxide (40% Cu) and copper oxychloride (50% Cu)] to
control olive fungal diseases. The residues of copper in olive leaves, harvested at different times, were evaluated by atomic absorption
spectrometry. At all the collection times, treated olive leaves had significantly higher copper contents, compared to the control. The different
copper amounts in pesticide formulations lowered the leaves contents in total phenols and hence their antioxidant properties. Olive
leaves sprayed with copper oxychloride possessed the highest copper levels and the lowest content in phenols, which influenced its antioxidant
activity (higher EC50 values for reducing power, scavenging effect on DPPH radicals and inhibition of erythrocyte hemolysis).
Leaves without copper residues proved to be a good natural source of antioxidants, giving values comparable to the reference
compounds
Copper residues in olives after olive tree treatments with three different copper formulations.
A Comment on the Topological Phase for Anti-Particles in a Lorentz-violating environment
Recently, a scheme to analyse topological phases in Quantum Mechanics by
means of the non-relativistic limit of fermions non-minimally coupled to a
Lorentz-breaking background has been proposed. In this letter, we show that the
fixed background, responsible for the Lorentz-symmetry violation, may induce
opposite Aharonov-Casher phases for a particle and its corresponding
antiparticle. We then argue that such a difference may be used to investigate
the asymmetry for particle/anti-particle as well as to propose bounds on the
associated Lorentz-symmetry violating parameters.Comment: 4 pages - A published versio
Caractéristiques et classification des principaux sols du Val Jaguaribe (Etat du Ceara, Brésil)
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