1,495 research outputs found
Hadron Spectroscopy with COMPASS at CERN
The aim of the COMPASS hadron programme is to study the light-quark hadron
spectrum, and in particular, to search for evidence of hybrids and glueballs.
COMPASS is a fixed-target experiment at the CERN SPS and features a two-stage
spectrometer with high momentum resolution, large acceptance, particle
identification and calorimetry. A short pilot run in 2004 resulted in the
observation of a spin-exotic state with consistent with the
debated . In addition, Coulomb production at low momentum transfer
data provide a test of Chiral Perturbation Theory. During 2008 and 2009, a
world leading data set was collected with hadron beam which is currently being
analysed. The large statistics allows for a thorough decomposition of the data
into partial waves. The COMPASS hadron data span over a broad range of channels
and shed light on several different aspects of QCD.Comment: 4 pages, 5 figure
Magnetic properties of single-crystalline CeCuGa3
The magnetic behavior of single-crystalline CeCuGa3 has been investigated.
The compound forms in a tetragonal BaAl4-type structure consisting of
rare-earth planes separated by Cu-Ga layers. If the Cu-Ga site disorder is
reduced, CeCuGa3 adopts the related, likewise tetragonal BaNiSn3-type
structure, in which the Ce ion are surrounded by different Cu and Ga layers and
the inversion symmetry is lost. In the literature conflicting reports about the
magnetic order of CeCuGa3 have been published. Single crystals with the
centrosymmetric structure variant exhibit ferromagnetic order below approx. 4 K
with a strong planar anisotropy. The magnetic behavior above the transition
temperature can be well understood by the crystal-field splitting of the 4f
Hund's rule ground-state multiplet of the Ce ions
Photobiont selectivity leads to ecological tolerance and evolutionary divergence in a polymorphic complex of lichenized fungi
Background and Aims The integrity and evolution of lichen symbioses depend on a fine-tuned combination of
algal and fungal genotypes. Geographically widespread species complexes of lichenized fungi can occur in habitats
with slightly varying ecological conditions, and it remains unclear howthis variation correlates with symbiont selectivity
patterns in lichens. In an attempt to address this question, .300 samples were taken of the globally distributed
and ecologically variable lichen-forming species complex Tephromela atra, together with closely allied species, in
order to study genetic diversity and the selectivity patterns of their photobionts.
\u2020 Methods Lichen thalli of T. atra and of closely related species T. grumosa, T. nashii and T. atrocaesia were
collected from six continents, across 24 countries and 62 localities representing a wide range of habitats. Analyses
of genetic diversity and phylogenetic relationships were carried out both for photobionts amplified directly from
the lichen thalli and from those isolated in axenic cultures. Morphological and anatomical traits were studied with
light and transmission electron microscopy in the isolated algal strains.
\u2020 Key Results Tephromela fungal species were found to associate with 12 lineages of Trebouxia. Five new clades
demonstrate the still-unrecognized genetic diversity of lichen algae. Culturable, undescribed lineageswere also characterized
by phenotypic traits. Strong selectivity of the mycobionts for the photobionts was observed in six monophyletic
Tephromela clades. Seven Trebouxia lineages were detected in the poorly resolved lineage T. atra sensu
lato, where co-occurrence of multiple photobiont lineages in single thalli was repeatedly observed.
\u2020Conclusions Lowselectivity apparently allows widespread lichen-forming fungi to establish successful symbioses
with locally adapted photobionts in a broader range of habitats. This flexibility might correlate with both lower phylogenetic
resolution and evolutionary divergence in species complexes of crustose lichen-forming fungi
Immunological characterization of chromogranins A and B and secretogranin II in the bovine pancreatic islet
Antisera against chromogranin A and B and secretogranin II were used for analysing the bovine pancreas by immunoblotting and immunohistochemistry. All three antigens were found in extracts of fetal pancreas by one dimensional immunoblotting. A comparison with the soluble proteins of chromaffin granules revealed that in adrenal medulla and in pancreas antigens which migrated identically in electrophoresis were present. In immunohistochemistry, chromogranin A was found in all pancreatic endocrine cell types with the exception of most pancreatic polypeptide-(PP-) producing cells. For chromogranin B, only a faint immunostaining was obtained. For secretorgranin II, A-and B-cells were faintly positive, whereas the majority of PP-cells exhibited a strong immunostaining for this antigen. These results establish that chromogranins A and B and secretogranin II are present in the endocrine pancreas, but that they exhibit a distinct cellular localization
Geoconservation, history of
[Excerto] The word "geoconservation" was probably used for the first time in Tasmania (Australia) in the beginning of the 1990s
(Sharples 1993). Sharples, a pioneer of Australian geoconservation, reports that during the period of 1993-1994, the
Forestry Commission of Tasmania prepared several reports with preliminary inventories of landforms in the state forests
of Tasmania in order to facilitate "the conservation of Earth systems ('Geoconservation')" (Sharples 1993). However,
initiatives to protect particular geological and geomorphological features started centuries before, during the seventeenth
century. The first example of the protection of geological features dates back to 1668, concerning the protection of the
Baumannshöhle cave in the Harz Mountains in Germany (Grube 1994)...info:eu-repo/semantics/publishedVersio
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An overview of ISCAT 2000
The Investigation of Sulfur Chemistry in the Antarctic Troposphere (ISCAT) took place over the timer period of 15 November to 31 December in the year 2000. The study location was the Amundsen Scott Station in Antarctica. ISCAT 2000 defines the second phase of a program designed to explore tropospheric chemistry in Antarctica. As in 1998, the 2000 ISCAT study revealed a strong oxidizing environment at South Pole (SP). During the 2000 investigation, however, the suite of measurements was greatly expanded. These new measurements established the recycling of reactive nitrogen as a critical component of this unique environment. This paper first presents the historical background leading up to the ISCAT 2000 observations; then it focuses on providing a summary of the year 2000 results and contrasts these with those recorded during 1998. Important developments made during the 2000 study included the recording of SP data for several species being emitted from the snowpack. These included NO, H 2O2 and CH2O. In this context, eddy-diffusion flux measurements provided the first quantitative estimates of the SP NO and NOx snow-to-atmosphere fluxes. This study also revealed that HNO 3 and HO2NO2 were major sink species for HOx and NOx radicals. And, it identified the critical factors responsible for SP NO levels exceeding those at other polar sites by nearly an order of magnitude. Finally, it reports on the levels of gas phase sulfur species and provides evidence indicating that the absence of DMS at SP is most likely due to its greatly shorten chemical lifetime in the near vicinity of the plateau. It is proposed that this is due to the influence of NO on the distribution of OH in the lower free troposphere over a region that extends well beyond the plateau itself. Details related to each of the above findings plus others can be found in the 11 accompanying Special Issue papers. © 2004 Elsevier Ltd. All rights reserved
Деталізація припису статті 67 Конституції України у вихідних конструкціях податково-правового регулювання
Multiwavelength Observations of 1ES 1959+650, One Year After the Strong Outburst of 2002
In April-May 2003, the blazar 1ES 1959+650 showed an increased level of X-ray
activity. This prompted a multiwavelength observation campaign with the Whipple
10 m gamma-ray telescope, the Rossi X-ray Timing Explorer, the Bordeaux Optical
Observatory, and the University of Michigan Radio Astrophysical Observatory. We
present the multiwavelength data taken from May 2, 2003 to June 7, 2003 and
compare the source characteristics with those measured during observations
taken during the years 2000 and 2002. The X-ray observations gave a data set
with high signal-to-noise light curves and energy spectra; however, the
gamma-ray observations did not reveal a major TeV gamma-ray flare. Furthermore,
we find that the radio and optical fluxes do not show statistically significant
deviations from those measured during the 2002 flaring periods. While the X-ray
flux and X-ray photon index appear correlated during subsequent observations,
the apparent correlation evolved significantly between the years 2000, 2002,
and 2003. We discuss the implications of this finding for the mechanism that
causes the flaring activity.Comment: 17 pages, 6 figures, 2 table
Anomalously large oxygen-ordering contribution to the thermal expansion of untwinned YBa2Cu3O6.95 single crystals: a glass-like transition near room temperature
We present high-resolution capacitance dilatometry studies from 5 - 500 K of
untwinned YBa2Cu3Ox (Y123) single crystals for x ~ 6.95 and x = 7.0. Large
contributions to the thermal expansivities due to O-ordering are found for x ~
6.95, which disappear below a kinetic glass-like transition near room
temperature. The kinetics at this glass transition is governed by an energy
barrier of 0.98 +- 0.07 eV, in very good agreement with other O-ordering
studies. Using thermodynamic arguments, we show that O-ordering in the Y123
system is particularly sensitive to uniaxial pressure (stress) along the chain
axis and that the lack of well-ordered chains in Nd123 and La123 is most likely
a consequence of a chemical-pressure effect.Comment: 4 pages, 3 figures, submitted to PR
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