14,040 research outputs found
Notas sobre el género Entoloma en el noroeste de la Península Ibérica (IV): Entoloma legionense, una nueva especie del subgénero Leptonia
Notes about the genus Entoloma in the Northwest of the Iberian Peninsula
(IV): Entoloma legionense, a new species of subgenus Leptonia. A new species of the genus
Entoloma, found in León (Northwest of the Iberian Peninsula) is described. Entoloma legionense,
sp. nov. differs from the most affine taxa of the subgenus Leptonia by the following combination
of characters: stipe partially green-blackish, cheilocystidia frequently thick-walled, a more diverse
in forms that in the neighbouring taxa, presence of encrusting pigment in numerous hyphae,
presence of caulobasidia and caulocystidia and fructification on rotten wood of beech.Notas sobre el género Entoloma en el Noroeste de la Península Ibérica (IV):
Entoloma legionense, una nueva especie del subgénero Leptonia. Se describe una especie
nueva del género Entoloma, encontrada en León (Noroeste de la Península Ibérica). Entoloma
legionense, sp. nov. se diferencia de los taxones más próximos del subgénero Leptonia en el que
se encuadra, por presentar la siguiente combinación de caracteres: estipe parcialmente verdenegruzco,
queilocistidios frecuentemente de pared gruesa, con una mayor diversidad de formas
respecto a los taxones más cercanos, presencia de pigmento incrustante en numerosas hifas,
presencia de caulobasidios y caulocistidios y fructificación sobre madera de haya, en
descomposición
Notas sobre el género Entoloma en el noroeste de la Península Ibérica (IV): Entoloma legionense, una nueva especie del subgénero Leptonia
Notes about the genus Entoloma in the Northwest of the Iberian Peninsula
(IV): Entoloma legionense, a new species of subgenus Leptonia. A new species of the genus
Entoloma, found in León (Northwest of the Iberian Peninsula) is described. Entoloma legionense,
sp. nov. differs from the most affine taxa of the subgenus Leptonia by the following combination
of characters: stipe partially green-blackish, cheilocystidia frequently thick-walled, a more diverse
in forms that in the neighbouring taxa, presence of encrusting pigment in numerous hyphae,
presence of caulobasidia and caulocystidia and fructification on rotten wood of beech.Notas sobre el género Entoloma en el Noroeste de la Península Ibérica (IV):
Entoloma legionense, una nueva especie del subgénero Leptonia. Se describe una especie
nueva del género Entoloma, encontrada en León (Noroeste de la Península Ibérica). Entoloma
legionense, sp. nov. se diferencia de los taxones más próximos del subgénero Leptonia en el que
se encuadra, por presentar la siguiente combinación de caracteres: estipe parcialmente verdenegruzco,
queilocistidios frecuentemente de pared gruesa, con una mayor diversidad de formas
respecto a los taxones más cercanos, presencia de pigmento incrustante en numerosas hifas,
presencia de caulobasidios y caulocistidios y fructificación sobre madera de haya, en
descomposición
Field theory simulation of Abelian-Higgs cosmic string cusps
We have performed a lattice field theory simulation of cusps in Abelian-Higgs
cosmic strings. The results are in accord with the theory that the portion of
the strings which overlaps near the cusp is released as radiation. The radius
of the string cores which must touch to produce the evaporation is
approximately in natural units. In general, the modifications to the
string shape due to the cusp may produce many cusps later in the evolution of a
string loop, but these later cusps will be much smaller in magnitude and more
closely resemble kinks.Comment: 9 pages, RevTeX, 13 figures with eps
Decay of flux vacua to nothing
We construct instanton solutions describing the decay of flux
compactifications of a gauge theory by generalizing the Kaluza-Klein
bubble of nothing. The surface of the bubble is described by a smooth
magnetically charged solitonic brane whose asymptotic flux is precisely that
responsible for stabilizing the 4d compactification. We describe several
instances of bubble geometries for the various vacua occurring in a
Einstein-Maxwell theory namely, AdS_4 x S^2, R^{1,3} x S^2, and dS_4 x S^2.
Unlike conventional solutions, the bubbles of nothing introduced here occur
where a {\em two}-sphere compactification manifold homogeneously degenerates.Comment: 31 pages, 15 figure
Bubbles from Nothing
Within the framework of flux compactifications, we construct an instanton
describing the quantum creation of an open universe from nothing. The solution
has many features in common with the smooth 6d bubble of nothing solutions
discussed recently, where the spacetime is described by a 4d compactification
of a 6d Einstein-Maxwell theory on S^2 stabilized by flux. The four-dimensional
description of this instanton reduces to that of Hawking and Turok. The choice
of parameters uniquely determines all future evolution, which we additionally
find to be stable against bubble of nothing instabilities.Comment: 19 pages, 6 figure
Strings at the bottom of the deformed conifold
We present solutions of the equations of motion of macroscopic F and D
strings extending along the non compact 4D sections of the conifold geometry
and winding around the internal directions. The effect of the Goldstone modes
associated with the position of the strings on the internal manifold can be
seen as a current on the string that prevents it from collapsing and allows the
possibility of static 4D loops. Its relevance in recent models of brane
inflation is discussed.Comment: 9+1 page
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