1,509 research outputs found
Competing Ground States in Triple-layered Sr4Ru3O10: Verging on Itinerant Ferromagnetism with Critical Fluctuations
Sr4Ru3O10 is characterized by a sharp metamagnetic transition and
ferromagnetic behavior occurring within the basal plane and along the c-axis,
respectively. Resistivity at magnetic field, B, exhibits low-frequency quantum
oscillations when B||c-axis and large magnetoresistivity accompanied by
critical fluctuations driven by the metamagnetism when B^c-axis. The complex
behavior evidenced in resistivity, magnetization and specific heat presented is
not characteristic of any obvious ground states, and points to an exotic state
that shows a delicate balance between fluctuations and order.Comment: 18 pages, 4 figure
Filling Control of the Mott Insulator Ca2RuO4
We have grown single crystals of electron doping system Ca2-xLaxRuO4 (0.00 <=
x <= 0.20) by a floating zone method. The first order metal/non-metal
transition and canted antiferromagnetic ordering occur for 0.00 < x < 0.15,
similar to those in the bandwidth controlled system Ca2-xSrxRuO4 (CSRO).
However, comparing with CSRO, we found a rather different metallic ground state
adjacent to the non-metallic ground state with canted antiferromagnetic order.
Instead of short-range antiferromagnetic correlation found in CSRO (0.20 <= x <
0.50), the metallic ground state of the present system is characterized by
strong ferromagnetic correlation.Comment: 8 pages, 8 figures (eps), submitted to J. Phys. Soc. Jp
Uncertainties of the Inclusive Higgs Production Cross Section at the Tevatron and the LHC
We study uncertainties of the predicted inclusive Higgs production cross
section due to the uncertainties of parton distribution functions (PDF).
Particular attention is given to bbH Yukawa coupling enhanced production
mechanisms in beyond SM scenarios, such as MSSM. The PDF uncertainties are
determined by the robust Lagrange Multiplier method within the CTEQ global
analysis framework. We show that PDF uncertainties dominate over theoretical
uncertainties of the perturbative calculation (usually estimated by the scale
dependence of the calculated cross sections), except for low Higgs masses at
LHC. Thus for the proper interpretation of any Higgs signal, and for better
understanding of the underlying electroweak symmetry breaking mechanism, it is
important to gain better control of the uncertainties of the PDFs.Comment: LaTeX, JHEP, 19 pages, 14 figure
Quantum Oscillations, Colossal Magnetoresistance and Magnetoelastic Interaction in Bilayered Ca3Ru2O7
We report magnetic and inter-plane transport properties of Ca3Ru2O7 at high
magnetic fields and low temperatures. Ca3Ru2O7 with a bilayered orthorhombic
structure is a Mott-like system with a narrow charge gap of 0.1eV. Of a host of
unusual physical phenomena revealed in this study, a few are particularly
intriguing: (1) a collapse of the c-axis lattice parameter at a metal-nonmetal
transition, TMI (=48 K), and a rapid increase of TMI with low uniaxial pressure
applied along the c-axis; (2) quantum oscillations in the gapped, nonmetallic
state for 20 mK<T<6.5 K; (3) tunneling colossal magnetoresistance, which yields
a precipitate drop in resistivity by as much as three orders of magnitude; (4)
different in-plane anisotropies of the colossal magnetoresistance and
magnetization. All results appear to indicate a highly anisotropic ground state
and a critical role of coupling between lattice and magnetism. The implication
of these phenomena is discussed.Comment: 27 pages, 9 figure
Society for Immunotherapy of Cancer (SITC) consensus definitions for resistance to combinations of immune checkpoint inhibitors with chemotherapy
Although immunotherapy can offer profound clinical benefit for patients with a variety of difficult-to-treat cancers, many tumors either do not respond to upfront treatment with immune checkpoint inhibitors (ICIs) or progressive/recurrent disease occurs after an interval of initial control. Improved response rates have been demonstrated with the addition of ICIs to cytotoxic therapies, leading to approvals from the US Food and Drug Administration and regulatory agencies in other countries for ICI-chemotherapy combinations in a number of solid tumor indications, including breast, head and neck, gastric, and lung cancer. Designing trials for patients with tumors that do not respond or stop responding to treatment with immunotherapy combinations, however, is challenging without uniform definitions of resistance. Previously, the Society for Immunotherapy of Cancer (SITC) published consensus definitions for resistance to single-agent anti-programmed cell death protein 1 (PD-1). To provide guidance for clinical trial design and to support analyses of emerging molecular and cellular data surrounding mechanisms of resistance to ICI-based combinations, SITC convened a follow-up workshop in 2021 to develop consensus definitions for resistance to multiagent ICI combinations. This manuscript reports the consensus clinical definitions for combinations of ICIs and chemotherapies. Definitions for resistance to ICIs in combination with targeted therapies and with other ICIs will be published in companion volumes to this paper
Nucleation in Systems with Elastic Forces
Systems with long-range interactions when quenced into a metastable state
near the pseudo-spinodal exhibit nucleation processes that are quite different
from the classical nucleation seen near the coexistence curve. In systems with
long-range elastic forces the description of the nucleation process can be
quite subtle due to the presence of bulk/interface elastic compatibility
constraints. We analyze the nucleation process in a simple 2d model with
elastic forces and show that the nucleation process generates critical droplets
with a different structure than the stable phase. This has implications for
nucleation in many crystal-crystal transitions and the structure of the final
state
Study of and
The decays and have been
investigated with a sample of 225.2 million events collected with the
BESIII detector at the BEPCII collider. The branching fractions are
determined to be and . Distributions of the angle
between the proton or anti-neutron and the beam direction are well
described by the form , and we find
for and
for . Our branching-fraction
results suggest a large phase angle between the strong and electromagnetic
amplitudes describing the decay.Comment: 16 pages, 13 figures, the 2nd version, submitted to PR
Thermoelectric properties of lead chalcogenide core-shell nanostructures
We present the full thermoelectric characterization of nanostructured bulk
PbTe and PbTe-PbSe samples fabricated from colloidal core-shell nanoparticles
followed by spark plasma sintering. An unusually large thermopower is found in
both materials, and the possibility of energy filtering as opposed to grain
boundary scattering as an explanation is discussed. A decreased Debye
temperature and an increased molar specific heat are in accordance with recent
predictions for nanostructured materials. On the basis of these results we
propose suitable core-shell material combinations for future thermoelectric
materials of large electric conductivities in combination with an increased
thermopower by energy filtering.Comment: 12 pages, 8 figure
A novel class of microRNA-recognition elements that function only within open reading frames.
MicroRNAs (miRNAs) are well known to target 3' untranslated regions (3' UTRs) in mRNAs, thereby silencing gene expression at the post-transcriptional level. Multiple reports have also indicated the ability of miRNAs to target protein-coding sequences (CDS); however, miRNAs have been generally believed to function through similar mechanisms regardless of the locations of their sites of action. Here, we report a class of miRNA-recognition elements (MREs) that function exclusively in CDS regions. Through functional and mechanistic characterization of these 'unusual' MREs, we demonstrate that CDS-targeted miRNAs require extensive base-pairing at the 3' side rather than the 5' seed; cause gene silencing in an Argonaute-dependent but GW182-independent manner; and repress translation by inducing transient ribosome stalling instead of mRNA destabilization. These findings reveal distinct mechanisms and functional consequences of miRNAs that target CDS versus the 3' UTR and suggest that CDS-targeted miRNAs may use a translational quality-control-related mechanism to regulate translation in mammalian cells
- …