363 research outputs found
Particle Acceleration in Pulsar Wind Nebulae: PIC modelling
We discuss the role of particle-in-cell (PIC) simulations in unveiling the
origin of the emitting particles in PWNe. After describing the basics of the
PIC technique, we summarize its implications for the quiescent and the flaring
emission of the Crab Nebula, as a prototype of PWNe. A consensus seems to be
emerging that, in addition to the standard scenario of particle acceleration
via the Fermi process at the termination shock of the pulsar wind, magnetic
reconnection in the wind, at the termination shock and in the Nebula plays a
major role in powering the multi-wavelength signatures of PWNe.Comment: 32 pages, 16 figures, to appear in the book "Modelling Nebulae"
edited by D. Torres for Springer, based on the invited contributions to the
workshop held in Sant Cugat (Barcelona), June 14-17, 201
A without-prejudice list of generic names of fungi for protection under the International Code of Nomenclature for algae, fungi, and plants
As a first step towards the production of a List of Protected Generic Names for Fungi, a without-prejudice list is presented here as a basis for future discussion and the production of a List for formal adoption. We include 6995 generic names out of the 17072 validly published names proposed for fungi and invite comments from all interested mycologists by 31 March 2014. The selection of names for inclusion takes note of recent major publications on different groups of fungi, and further the decisions reached so far by international working groups concerned with particular families or genera. Changes will be sought in the Code to provide for this and lists at other ranks to be protected against any competing unlisted names, and to permit the inclusion of names of lichen-forming fungi. A revised draft will be made available for further discussion at the 10th International Mycological Congress in Bangkok in August 2014. A schedule is suggested for the steps needed to produce a list for adoption by the International Botanical Congress in August 2017. This initiative provides mycologists with an opportunity to place nomenclature at the generic level on a more secure and stable base
Opportunistic, human-pathogenic species in the Herpotrichiellaceae are phenotypically similar to saprobic or phytopathogenic species in the Venturiaceae
Although morphologically similar, species of Cladophialophora
(Herpotrichiellaceae) were shown to be phylogenetically distinct from
Pseudocladosporium (Venturiaceae), which was revealed to be
synonymous with the older genus, Fusicladium. Other than being
associated with human disorders, species of Cladophialophora were
found to also be phytopathogenic, or to occur as saprobes on organic material,
or in water, fruit juices, or sports drinks, along with species of
Exophiala. Caproventuria and Metacoleroa were
confirmed to be synonyms of Venturia, which has Fusicladium
(= Pseudocladosporium) anamorphs. Apiosporina, based on
A. collinsii, clustered basal to the Venturia clade, and
appears to represent a further synonym. Several species with a
pseudocladosporium-like morphology in vitro represent a sister clade
to the Venturia clade, and are unrelated to Polyscytalum.
These taxa are newly described in Fusicladium, which is
morphologically close to Anungitea, a heterogeneous genus with
unknown phylogenetic affinity. In contrast to the
Herpotrichiellaceae, which were shown to produce numerous
synanamorphs in culture, species of the Venturiaceae were
morphologically and phylogenetically more uniform. Several new species and new
combinations were introduced in Cladophialophora, Cyphellophora
(Herpotrichiellaceae), Exophiala, Fusicladium, Venturia
(Venturiaceae), and Cylindrosympodium (incertae
sedis)
Inclusive production of and mesons in charged current interactions
The inclusive production of the meson resonances ,
and in neutrino-nucleus charged current interactions has been
studied with the NOMAD detector exposed to the wide band neutrino beam
generated by 450 GeV protons at the CERN SPS. For the first time the
meson is observed in neutrino interactions. The statistical
significance of its observation is 6 standard deviations. The presence of
in neutrino interactions is reliably established. The average
multiplicity of these three resonances is measured as a function of several
kinematic variables. The experimental results are compared to the
multiplicities obtained from a simulation based on the Lund model. In addition,
the average multiplicity of in antineutrino - nucleus
interactions is measured.Comment: 23 pages, 14 figures, 8 tables. To appear in Nucl. Phys.
Mycosphaerella is polyphyletic
Mycosphaerella, one of the largest genera of ascomycetes,
encompasses several thousand species and has anamorphs residing in more than
30 form genera. Although previous phylogenetic studies based on the ITS rDNA
locus supported the monophyly of the genus, DNA sequence data derived from the
LSU gene distinguish several clades and families in what has hitherto been
considered to represent the Mycosphaerellaceae. Several important
leaf spotting and extremotolerant species need to be disposed to the genus
Teratosphaeria, for which a new family, the
Teratosphaeriaceae, is introduced. Other distinct clades represent
the Schizothyriaceae, Davidiellaceae, Capnodiaceae,
and the Mycosphaerellaceae. Within the two major clades, namely
Teratosphaeriaceae and Mycosphaerellaceae, most anamorph
genera are polyphyletic, and new anamorph concepts need to be derived to cope
with dual nomenclature within the Mycosphaerella complex
Biodiversity in the Cladosporium herbarum complex (Davidiellaceae, Capnodiales), with standardisation of methods for Cladosporium taxonomy and diagnostics
The Cladosporium herbarum complex comprises five species for which
Davidiella teleomorphs are known. Cladosporium herbarum s.
str. (D. tassiana), C. macrocarpum (D.
macrocarpa) and C. bruhnei (D. allicina) are
distinguishable by having conidia of different width, and by teleomorph
characters. Davidiella variabile is introduced as teleomorph of
C. variabile, a homothallic species occurring on Spinacia,
and D. macrospora is known to be the teleomorph of C. iridis
on Iris spp. The C. herbarum complex combines low molecular
distance with a high degree of clonal or inbreeding diversity. Entities differ
from each other by multilocus sequence data and by phenetic differences, and
thus can be interpreted to represent individual taxa. Isolates of the C.
herbarum complex that were formerly associated with opportunistic human
infections, cluster with C. bruhnei. Several species are newly
described from hypersaline water, namely C. ramotenellum, C.
tenellum, C. subinflatum, and C. herbaroides.
Cladosporium pseudiridis collected from Iris sp. in New
Zealand, is also a member of this species complex and shown to be distinct
from C. iridis that occurs on this host elsewhere in the world. A
further new species from New Zealand is C. sinuosum on Fuchsia
excorticata. Cladosporium antarcticum is newly described from a
lichen, Caloplaca regalis, collected in Antarctica, and C.
subtilissimum from grape berries in the U.S.A., while the new combination
C. ossifragi, the oldest valid name of the Cladosporium
known from Narthecium in Europe, is proposed. Standard protocols and
media are herewith proposed to facilitate future morphological examination of
Cladosporium spp. in culture, and neotypes or epitypes are proposed
for all species treated
The PHENIX Experiment at RHIC
The physics emphases of the PHENIX collaboration and the design and current
status of the PHENIX detector are discussed. The plan of the collaboration for
making the most effective use of the available luminosity in the first years of
RHIC operation is also presented.Comment: 5 pages, 1 figure. Further details of the PHENIX physics program
available at http://www.rhic.bnl.gov/phenix
Phylogeny and ecology of the ubiquitous saprobe Cladosporium sphaerospermum, with descriptions of seven new species from hypersaline environments
Saprobic Cladosporium isolates morphologically similar to C.
sphaerospermum are phylogenetically analysed on the basis of DNA
sequences of the ribosomal RNA gene cluster, including the internal
transcribed spacer regions ITS1 and ITS2, the 5.8S rDNA (ITS) and the small
subunit (SSU) rDNA as well as β-tubulin and actin gene introns and exons.
Most of the C. sphaerospermum-like species show halotolerance as a
recurrent feature. Cladosporium sphaerospermum, which is
characterised by almost globose conidia, is redefined on the basis of its
ex-neotype culture. Cladosporium dominicanum, C.
psychrotolerans, C. velox, C. spinulosum and C.
halotolerans, all with globoid conidia, are newly described on the basis
of phylogenetic analyses and cryptic morphological and physiological
characters. Cladosporium halotolerans was isolated from hypersaline
water and bathrooms and detected once on dolphin skin. Cladosporium
dominicanum and C. velox were isolated from plant material and
hypersaline water. Cladosporium psychrotolerans, which grows well at
4 °C but not at 30 °C, and C. spinulosum, having
conspicuously ornamented conidia with long digitate projections, are currently
only known from hypersaline water. We also newly describe C. salinae
from hypersaline water and C. fusiforme from hypersaline water and
animal feed. Both species have ovoid to ellipsoid conidia and are therefore
reminiscent of C. herbarum. Cladosporium langeronii (=
Hormodendrum langeronii) previously described as a pathogen on human
skin, is halotolerant but has not yet been recorded from hypersaline
environments
Phylogenetic lineages in the Capnodiales
The Capnodiales incorporates plant and human pathogens,
endophytes, saprobes and epiphytes, with a wide range of nutritional modes.
Several species are lichenised, or occur as parasites on fungi, or animals.
The aim of the present study was to use DNA sequence data of the nuclear
ribosomal small and large subunit RNA genes to test the monophyly of the
Capnodiales, and resolve families within the order. We designed
primers to allow the amplification and sequencing of almost the complete
nuclear ribosomal small and large subunit RNA genes. Other than the
Capnodiaceae (sooty moulds), and the Davidiellaceae, which
contains saprobes and plant pathogens, the order presently incorporates
families of major plant pathological importance such as the
Mycosphaerellaceae, Teratosphaeriaceae and
Schizothyriaceae. The Piedraiaceae was not supported, but
resolves in the Teratosphaeriaceae. The Dissoconiaceae is
introduced as a new family to accommodate Dissoconium and
Ramichloridium. Lichenisation, as well as the ability to be saprobic
or plant pathogenic evolved more than once in several families, though the
taxa in the upper clades of the tree lead us to conclude that the strictly
plant pathogenic, nectrotrophic families evolved from saprobic ancestors
(Capnodiaceae), which is the more primitive state
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