245 research outputs found
High-Field ESR Measurements of S=1/2 Kagome Lattice Antiferromagnet BaCuVO(OH)
High-field electron spin resonance (ESR) measurements have been performed on
vesignieite BaCuVO(OH), which is considered as a nearly ideal
model substance of =1/2 kagome antiferromagnet, in the temperature region
from 1.9 to 265 K. The frequency region is from 60 to 360 GHz and the applied
pulsed magnetic field is up to 16 T. Observed g-value and linewidth show the
increase below 20 K, which suggest the development of the short range order.
Moreover, a gapless spin liquid ground state is suggested from the
frequency-field relation at 1.9 K.Comment: 5 pages, 6 figures, jpsj2 class file, to be published in J. Phys.
Soc. Jp
Microscopic and macroscopic properties of A-superstatistics
The microscopic and the macroscopic properties of A-superstatistics, related
to the class A(0,n-1)\equiv sl(1|n) of simple Lie superalgebras are
investigated. The algebra sl(1|n) is described in terms of generators f_1^\pm,
>..., f_n^\pm, which satisfy certain triple relations and are called Jacobson
generators. The Fock spaces of A-superstatistics are investigated and the Pauli
principle of the corresponding statistics is formulated. Some thermal
properties of A-superstatistics are constructed under the assumption that the
particles interact only via statistical interaction imposed by the Pauli
principle. The grand partition function and the average number of particles are
written down explicitly in the general case and in two particular examples: 1)
the particles have one and the same energy and chemical potential; 2) the
energy spectrum of the orbitals is equidistant.Comment: 26 pages, 3 figure
Comparison of Isoscalar Vector Meson Production Cross Sections in Proton-Proton Collisions
The reaction was investigated with the TOF
spectrometer, which is an external experiment at the accelerator COSY
(Forschungszentrum J\"ulich, Germany). Total as well as differential cross
sections were determined at an excess energy of (). Using the total cross section of for the
reaction determined here and existing data for the reaction
, the ratio
turns out to be
significantly larger than expected by the Okubo-Zweig-Iizuka (OZI) rule. The
uncertainty of this ratio is considerably smaller than in previous
determinations. The differential distributions show that the
production is still dominated by S-wave production at this excess energy,
however higher partial waves clearly contribute. A comparison of the measured
angular distributions for production to published distributions for
production at shows that the data are consistent with an
identical production mechanism for both vector mesons
Production of mesons in proton-proton collisions
The cross section for the production of mesons in proton-proton
collisions has been measured in a previously unexplored region of incident
energies. Cross sections were extracted at 92 MeV and 173 MeV excess energy,
respectively. The angular distribution of the at =173 MeV is
strongly anisotropic, demonstrating the importance of partial waves beyond pure
s-wave production at this energy.Comment: 12 pages, 4 figures submitted to Physics Letters B v2: figure 1
added, discussion detailing the data analysis, figure 3 (fig. 2 in v1)
modified in line styles and systematic errors displayed on dat
Complex circular subsidence structures in tephra deposited on large blocks of ice: Varða tuff cone, Öræfajökull, Iceland
Several broadly circular structures up to 16 m in diameter, into which higher strata have sagged and locally collapsed, are present in a tephra outcrop on southwest Öræfajökull, southern Iceland. The tephra was sourced in a nearby basaltic tuff cone at Varða. The structures have not previously been described in tuff cones, and they probably formed by the melting out of large buried blocks of ice emplaced during a preceding jökulhlaup that may have been triggered by a subglacial eruption within the Öræfajökull ice cap. They are named ice-melt subsidence structures, and they are analogous to kettle holes that are commonly found in proglacial sandurs and some lahars sourced in ice-clad volcanoes. The internal structure is better exposed in the Varða examples because of an absence of fluvial infilling and reworking, and erosion of the outcrop to reveal the deeper geometry. The ice-melt subsidence structures at Varða are a proxy for buried ice. They are the only known evidence for a subglacial eruption and associated jökulhlaup that created the ice blocks. The recognition of such structures elsewhere will be useful in reconstructing more complete regional volcanic histories as well as for identifying ice-proximal settings during palaeoenvironmental investigations
A case report of pulmonary tumor thrombotic microangiopathy (PTTM) caused by esophageal squamous cell carcinoma
DEFORMATION and RUPTURE of the OCEANIC CRUST MAY CONTROL GROWTH of HAWAIIAN VOLCANOES
Hawaiian volcanoes are formed by the eruption of large quantities of basaltic magma related to hot- spot activity below the Pacific Plate(1,2). Despite the apparent simplicity of the parent process emission of magma onto the oceanic crust - the resulting edifices display some topographic complexity(3-5). Certain features, such as rift zones and large flank slides, are common to all Hawaiian volcanoes, indicating similarities in their genesis; however, the underlying mechanism controlling this process remains unknown(6,7). Here we use seismological investigations and finite-element mechanical modelling to show that the load exerted by large Hawaiian volcanoes can be sufficient to rupture the oceanic crust. This intense deformation, combined with the accelerated subsidence of the oceanic crust and the weakness of the volcanic edifice/ oceanic crust interface, may control the surface morphology of Hawaiian volcanoes, especially the existence of their giant flank instabilities(8-10). Further studies are needed to determine whether such processes occur in other active intraplate volcanoes
The App-Runx1 Region Is Critical for Birth Defects and Electrocardiographic Dysfunctions Observed in a Down Syndrome Mouse Model
Down syndrome (DS) leads to complex phenotypes and is the main genetic cause of birth defects and heart diseases. The Ts65Dn DS mouse model is trisomic for the distal part of mouse chromosome 16 and displays similar features with post-natal lethality and cardiovascular defects. In order to better understand these defects, we defined electrocardiogram (ECG) with a precordial set-up, and we found conduction defects and modifications in wave shape, amplitudes, and durations in Ts65Dn mice. By using a genetic approach consisting of crossing Ts65Dn mice with Ms5Yah mice monosomic for the App-Runx1 genetic interval, we showed that the Ts65Dn viability and ECG were improved by this reduction of gene copy number. Whole-genome expression studies confirmed gene dosage effect in Ts65Dn, Ms5Yah, and Ts65Dn/Ms5Yah hearts and showed an overall perturbation of pathways connected to post-natal lethality (Coq7, Dyrk1a, F5, Gabpa, Hmgn1, Pde10a, Morc3, Slc5a3, and Vwf) and heart function (Tfb1m, Adam19, Slc8a1/Ncx1, and Rcan1). In addition cardiac connexins (Cx40, Cx43) and sodium channel sub-units (Scn5a, Scn1b, Scn10a) were found down-regulated in Ts65Dn atria with additional down-regulation of Cx40 in Ts65Dn ventricles and were likely contributing to conduction defects. All these data pinpoint new cardiac phenotypes in the Ts65Dn, mimicking aspects of human DS features and pathways altered in the mouse model. In addition they highlight the role of the App-Runx1 interval, including Sod1 and Tiam1, in the induction of post-natal lethality and of the cardiac conduction defects in Ts65Dn. These results might lead to new therapeutic strategies to improve the care of DS people
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