143 research outputs found
Análisis polínico de mieles en las regiones de Ouazzane y Costa Atlántica (Noroeste de Marruecos)
Análisis polínico de mieles en las regiones de Ouazzane y Costa Atlántica (Noroeste de Marruecos). Se ha realizado el análisis microscópico de 13 muestras de miel de las regiones de Ouazzane y Costa Atlántica. Las muestras fueron proporcionadas directamente por los apicultores, en su mayoría aficionados. Los resultados reflejan que el néctar de las flores es la principal fuente de miel en el territorio y que siete de las muestras son pobres polinicamente, con 4.600-47.800 GP (Clase I y II de Maurizio), dos muestras presentan una riqueza media, con 189.000-209.700 GP (Clase III), y cuatro son ricas o muy ricas, con 872.000-2.950.000 GP (Clases IV y V). Se han identificado 63 taxones por el análisis microscópico, resultando seis de las mieles monoflorales: dos de Eucalyptus sp., dos de Lythrum sp., una de Leucojum sp. y una de Citrus sp
Solutions for the General, Confluent and Biconfluent Heun equations and their connection with Abel equations
In a recent paper, the canonical forms of a new multi-parameter class of Abel
differential equations, so-called AIR, all of whose members can be mapped into
Riccati equations, were shown to be related to the differential equations for
the hypergeometric 2F1, 1F1 and 0F1 functions. In this paper, a connection
between the AIR canonical forms and the Heun General (GHE), Confluent (CHE) and
Biconfluent (BHE) equations is presented. This connection fixes the value of
one of the Heun parameters, expresses another one in terms of those remaining,
and provides closed form solutions in terms of pFq functions for the resulting
GHE, CHE and BHE, respectively depending on four, three and two irreducible
parameters. This connection also turns evident what is the relation between the
Heun parameters such that the solutions admit Liouvillian form, and suggests a
mechanism for relating linear equations with N and N-1 singularities through
the canonical forms of a non-linear equation of one order less.Comment: Original version submitted to Journal of Physics A: 16 pages, related
to math.GM/0002059 and math-ph/0402040. Revised version according to
referee's comments: 23 pages. Sign corrected (June/17) in formula (79).
Second revised version (July/25): 25 pages. See also
http://lie.uwaterloo.ca/odetools.ht
Incomplete beta-function expansions of the solutions to the confluent Heun equation
Several expansions of the solutions to the confluent Heun equation in terms
of incomplete Beta functions are constructed. A new type of expansion involving
certain combinations of the incomplete Beta functions as expansion functions is
introduced. The necessary and sufficient conditions when the derived expansions
are terminated, thus generating closed-form solutions, are discussed. It is
shown that termination of a Beta-function series solution always leads to a
solution that is necessarily an elementary function
Self-Similar Collapse of Conformally Coupled Scalar Fields
A massless scalar field minimally coupled to the gravitational field in a
simplified spherical symmetry is discussed. It is shown that, in this case, the
solution found by Roberts, describing a scalar field collapse, is in fact the
most general one. Taking that solution as departure point, a study of the
gravitational collapse for the self-similar conformal case is presented.Comment: 9 pages, accepted for publication, Classical and Quantum Gravity.
Available at http://dft.if.uerj.br/preprint/e-17.tex or at
ftp://dft.if.uerj.br/preprint/e-17.tex . Figures can be obtained on request
at [email protected]
Diversity of xerotolerant and xerophilic fungi in honey
Fungi can colonize most of the substrata on Earth. Honey, a sugary food produced by bees (and other insects) has
been studied little in terms of its fungal diversity. We have surveyed and evaluated the presence of xerotolerant
and xerophilic fungi in a set of honey bee samples collected from across Spain. From 84 samples, a total of 104
fungal strains were isolated, and morphologically and phylogenetically characterized. We identified 32 species
distributed across 16 genera, most of them belonging to the ascomycetous genera Aspergillus, Bettsia, Candida,
Eremascus, Monascus, Oidiodendron, Penicillium, Skoua, Talaromyces and Zygosaccharomyces. As a result of this
survey, eight new taxa are proposed: i.e. the new family Helicoarthrosporaceae, two new genera, Helicoarthrosporum
and Strongyloarthrosporum in Onygenales; three new species of Eurotiales, Talaromyces affinitatimellis, T.
basipetosporus, and T. brunneosporus; and two new species of Myxotrichaceae, Oidiodendron mellicola, and Skoua
asexualis.Instituto de Ciencia, Tecnología e Innovación. (México)Consejo Nacional de Ciencia y Tecnología (México)Ministerio de Economía y Competitividad español CGL2017–88094-
Phenolic compounds and color of labeled resin spurge honey and their correlations with pollen content
Our aim in this study was to outline phenolic and color characteristic that characterize the labeled unifloral resin spurge (Euphorbia resinifera) honey. With respect to phenolic composition, 17 phenolic compounds have been analyzed in the 29 honey samples. The proposed markers (syringic acid, ethyl gallate, m-coumaric acid and naringenin) might help to the enhancement of this honey type and thus, guarantee its commercial value. The color characterization by diffuse reflectance spectrophotometry revealed typical values of light amber honey (lightness ranged from 36 to 70 units, and chroma from 18 to 30 units). On the other hand, many correlations between the color attributes and phenolic acids, total phenolic compounds, caffeic acid, p- and m-coumaric acids and hesperidin have been demonstrated, also, correlation between phenols, color parameters and percentage of pollen of E. resinifera has been found. This study is one of the rare researches which have correlated the CIELAB color parameters with the individual phenolic acids and flavonoid compounds within the same unifloral honey
Chaos in Anisotropic Pre-Inflationary Universes
We study the dynamics of anisotropic Bianchi type-IX models with matter and
cosmological constant. The models can be thought as describing the role of
anisotropy in the early stages of inflation. The concurrence of the
cosmological constant and anisotropy are sufficient to produce a chaotic
dynamics in the gravitational degrees of freedom, connected to the presence of
a critical point of saddle-center type in the phase space of the system. The
invariant character of chaos is guaranteed by the topology of the cylinders
emanating from unstable periodic orbits in the neighborhood of the
saddle-center. We discuss a possible mechanism for amplification of specific
wavelengths of inhomogeneous fluctuations in the models. A geometrical
interpretation is given for Wald's inequality in terms of invariant tori and
their destruction by increasing values of the cosmological constant.Comment: 14 pages, figures available under request. submitted to Physical
Review
Early diversification and permeable species boundaries in the Mediterranean firs
BACKGROUND AND AIMS:
Inferring the evolutionary relationships of species and their boundaries is critical in order to understand patterns of diversification and their historical drivers. Despite Abies (Pinaceae) being the second most diverse group of conifers, the evolutionary history of Circum-Mediterranean firs (CMF) remains under debate.
METHODS:
We used restriction site associated DNA sequencing (RAD-seq) on all proposed CMF taxa to investigate their phylogenetic relationships and taxonomic status.
KEY RESULTS:
Based on thousands of genome-wide SNPs, we present here the first formal test of species delimitation, and the first fully resolved, complete species tree for CMF. We discovered that all previously recognized taxa in the Mediterranean should be treated as independent species, with the exception of A. tazaotana and A. marocana. An unexpectedly early pulse of speciation in the Oligocene-Miocene boundary is here documented for the group, pre-dating previous hypotheses by millions of years, revealing a complex evolutionary history encompassing both ancient and recent gene flow between distant lineages.
CONCLUSIONS:
Our phylogenomic results contribute to shed light on conifers' diversification. Our efforts to resolve the CMF phylogenetic relationships help refine their taxonomy and our knowledge of their evolutio
[SADE] A Maple package for the Symmetry Analysis of Differential Equations
We present the package SADE (Symmetry Analysis of Differential Equations) for
the determination of symmetries and related properties of systems of
differential equations. The main methods implemented are: Lie, nonclassical,
Lie-B\"acklund and potential symmetries, invariant solutions, first-integrals,
N\"other theorem for both discrete and continuous systems, solution of ordinary
differential equations, reduction of order or dimension using Lie symmetries,
classification of differential equations, Casimir invariants, and the
quasi-polynomial formalism for ODE's (previously implemented in the package
QPSI by the authors) for the determination of quasi-polynomial first-integrals,
Lie symmetries and invariant surfaces. Examples of use of the package are
given
Kalb-Ramond excitations in a thick-brane scenario with dilaton
We compute the full spectrum and eigenstates of the Kalb-Ramond field in a
warped non-compact Randall-Sundrum -type five-dimensional spacetime in which
the ordinary four-dimensional braneworld is represented by a sine-Gordon
soliton. This 3-brane solution is fully consistent with both the warped
gravitational field and bulk dilaton configurations. In such a background we
embed a bulk antisymmetric tensor field and obtain, after reduction, an
infinite tower of normalizable Kaluza-Klein massive components along with a
zero-mode. The low lying mass eigenstates of the Kalb-Ramond field may be
related to the axion pseudoscalar. This yields phenomenological implications on
the space of parameters, particularly on the dilaton coupling constant. Both
analytical and numerical results are given.Comment: 10 pages, 13 figures, and 2 tables. Final version to appear in The
European Physical Journal
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