12,046 research outputs found
Mott-Hubbard quantum criticality in paramagnetic CMR pyrochlores
We present a correlated {\it ab initio} description of the paramagnetic phase
of TlMnO, employing a combined local density approximation (LDA)
with multiorbital dynamical mean field theory (DMFT) treatment. We show that
the insulating state observed in this colossal magnetoresistance (CMR)
pyrochlore is determined by strong Mn intra- and inter-orbital local
electron-electron interactions. Hybridization effects are reinforced by the
correlation-induced spectral weight transfer. Our result coincides with optical
conductivity measurements, whose low energy features are remarkably accounted
for by our theory. Based on this agreement, we study the disorder-driven
insulator-metal transition of doped compounds, showing the proximity of
TlMnO to quantum phase transitions, in agreement with recent
measurements.Comment: 4 pages, 4 figure
A Robust Filter for the BeppoSAX Gamma Ray Burst Monitor Triggers
The BeppoSAX Gamma Ray Burst Monitor (GRBM) is triggered any time a
statistically significant counting excess is simultaneously revealed by at
least two of its four independent detectors. Several spurious effects,
including highly ionizing particles crossing two detectors, are recorded as
onboard triggers. In fact, a large number of false triggers is detected, in the
order of 10/day. A software code, based on an heuristic algorithm, was written
to discriminate between real and false triggers. We present the results of the
analysis on an homogeneous sample of GRBM triggers, thus providing an estimate
of the efficiency of the GRB detection system consisting of the GRBM and the
software.Comment: Proc. 5th Huntsville GRB Symposiu
Lymphocyte Subsets and Inflammatory Cytokines of Monoclonal Gammopathy of Undetermined Significance and Multiple Myeloma
Almost all multiple myeloma (MM) cases have been demonstrated to be linked to earlier monoclonal gammopathy of undetermined significance (MGUS). Nevertheless, there are no identified characteristics in the diagnosis of MGUS that have been helpful in differentiating subjects whose cancer may progress to a malignant situation. Regarding malignancy, the role of lymphocyte subsets and cytokines at the beginning of neoplastic diseases is now incontestable. In this review, we have concentrated our attention on the equilibrium between the diverse lymphocyte subsets and the cytokine system and summarized the current state of knowledge, providing an overview of the condition of the entire system in MGUS and MM. In an age where the therapy of neoplastic monoclonal gammopathies largely relies on drugs capable of acting on the immune system (immunomodulants, immunological checkpoint inhibitors, CAR-T), detailed knowledge of the the differences existing in benign and neoplastic forms of gammopathy is the main foundation for the adequate and optimal use of new drugs
FEM Updating of the Heritage Court Building Structure
This paper describes results of a model updating study conducted on a 15-storey reinforced concrete shear core building. The output-only modal identification results obtained from ambient vibration measurements of the building were used to update a finite element model of the structure. The starting model of the structure was developed from the information provided in the design documentation of the building. Different parameters of the model were then modified using an automated procedure to improve the correlation between measured and calculated modal parameters. Careful attention was placed to the selection of the parameters to be modified by the updating software in order to ensure that the necessary changes to the model were realistic and physically realisable and meaningfull. The paper highlights the model updating process and provides an assessment of the usefulness of using an automatic model updating procedure combined with results from an output-only modal identification
An insight into Capella (alpha Aurigae): from the extent of core overshoot to its evolutionary history
The binary star alpha Aurigae (otherwise known as Capella) is extremely
important to understand the core hydrogen and helium burning phases of the
stars, as the primary star is likely evolving through the core helium burning
phase, and the masses of the two components are 2.5 Msun and 2.6 Msun, which
fall into a mass range for which the extention of the core overshoot during the
main sequence phase is uncertain. We aim at deriving the extent of the core
overshoot experienced during the core burning phases and testing the efficiency
of the convective transport of energy in the external envelope, by comparing
results from stellar evolution modelling with the results from the
observations. We consider evolutionary tracks calculated on purpose for the
present work, for the primary and secondary star of Capella. We determine the
extent of the extra-mixing from the core during the main sequence evolution and
the age of the system, by requiring that the effective temperatures and surface
gravities of the model stars reproduce those derived from the observations at
the same epoch. We further check consistency between the observed and predicted
surface chemistry of the stars. Consistency between results from stellar
evolution modelling and the observations of Capella is found when extra-mixing
from the core is assumed, the extent of the extra-mixed zone being of the order
of 0.25 H_P. The age of the system is estimated to be 710 Myr. These results
allow to nicely reproduce the observed surface chemistry, particularly the
recent determination of the 12C/13C ratio based on LBT (Large Binocular
Telescope) and VATT (Vatican Advanced Technology Telescope) observation
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