123 research outputs found
High order quantum decoherence via multi-particle amplitude for boson system
In this paper we depict the high order quantum coherence of a boson system by
using the multi-particle wave amplitude, whose norm square is just the high
order correlation function. This multi-time amplitude can be shown to be a
superposition of several "multi-particle paths". When the environment or a
apparatus entangles with them to form a generalized "which-way" measurement for
many particle system, the quantum decoherence happens in the high order case
dynamically. An explicit illustration is also given with an intracavity system
of two modes interacting with a moving mirror.Comment: 7 pages, revtex, 4 eps figure
Effects of crossed states on photoluminescence excitation spectroscopy of InAs quantum dots
In this report, the influence of the intrinsic transitions between bound-to-delocalized states (crossed states or quasicontinuous density of electron-hole states) on photoluminescence excitation (PLE) spectra of InAs quantum dots (QDs) was investigated. The InAs QDs were different in size, shape, and number of bound states. Results from the PLE spectroscopy at low temperature and under a high magnetic field (up to 14 T) were compared. Our findings show that the profile of the PLE resonances associated with the bound transitions disintegrated and broadened. This was attributed to the coupling of the localized QD excited states to the crossed states and scattering of longitudinal acoustical (LA) phonons. The degree of spectral linewidth broadening was larger for the excited state in smaller QDs because of the higher crossed joint density of states and scattering rate
Antiferromagnetism and superconductivity of the two-dimensional extended t–J model
The mechanism of high-temperature superconductivity (HTS) and the correlation between the antiferromagnetic long-range order (AFLRO) and superconductivity (SC) phases are the central issues of the study of HTS theory. SC and AFLRO of the hole-doped two-dimensional extended t- J model are studied by the variational Monte Carlo method. The results show that SC is greatly enhanced by the long-range hopping terms t' and t" for the optimal and overdoped cases. The phase of coexisting SC and AFM in the t-J model disappears when t and t" are included. It is concluded that the extended t-J model provides a more accurate description for HTS than the traditional t-J model does. The momentum distribution function n(k) and the shape of Fermi surface play critical roles for establishing the phase diagram of HTS materials
Meta-Stable Dynamical Supersymmetry Breaking Near Points of Enhanced Symmetry
We show that metastable supersymmetry breaking is generic near certain
enhanced symmetry points of gauge theory moduli spaces. Our model consists of
two sectors coupled by a singlet and combines dynamical supersymmetry breaking
with an O'Raifeartaigh mechanism in terms of confined variables. All relevant
mass parameters, including the supersymmetry breaking scale, are generated
dynamically. The metastable vacua appear as a result of a balance between
non-perturbative and perturbative quantum effects along a pseudo-runaway
direction.Comment: 27 pages, harvmac, 6 figure
Identifying the Independent Inertial Parameter Space of Robot Manipulators
This paper presents a new approach to the problem of finding the minimum number of inertial parameters of robot manipulator dynamic equations of motion. Based upon the energy difference equation, it is equally applica ble to serial link manipulators as well as graph structured manipulators. The method is conceptually simple, compu tationally efficient, and easy to implement. In particular, the manipulator kinematics and the joint positions and velocities are the only inputs to the algorithm. Applica tions to a serial link and a graph structured manipulator are illustrated.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67982/2/10.1177_027836499101000606.pd
A Note on Domain Walls and the Parameter Space of N=1 Gauge Theories
We study the spectrum of BPS domain walls within the parameter space of N=1
U(N) gauge theories with adjoint matter and a cubic superpotential. Using a low
energy description obtained by compactifying the theory on R^3 x S^1, we
examine the wall spectrum by combining direct calculations at special points in
the parameter space with insight drawn from the leading order potential between
minimal walls, i.e those interpolating between adjacent vacua. We show that the
multiplicity of composite BPS walls -- as characterised by the CFIV index --
exhibits discontinuities on marginal stability curves within the parameter
space of the maximally confining branch. The structure of these marginal
stability curves for large N appears tied to certain singularities within the
matrix model description of the confining vacua.Comment: 33 pages, LaTeX, 6 eps figures; v2: references adde
Supersymmetric Gauge Theories, Intersecting Branes and Free Fermions
We show that various holomorphic quantities in supersymmetric gauge theories
can be conveniently computed by configurations of D4-branes and D6-branes.
These D-branes intersect along a Riemann surface that is described by a
holomorphic curve in a complex surface. The resulting I-brane carries
two-dimensional chiral fermions on its world-volume. This system can be mapped
directly to the topological string on a large class of non-compact Calabi-Yau
manifolds. Inclusion of the string coupling constant corresponds to turning on
a constant B-field on the complex surface, which makes this space
non-commutative. Including all string loop corrections the free fermion theory
is elegantly formulated in terms of holonomic D-modules that replace the
classical holomorphic curve in the quantum case.Comment: 67 pages, 6 figure
An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics
For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types
Driver Fusions and Their Implications in the Development and Treatment of Human Cancers.
Gene fusions represent an important class of somatic alterations in cancer. We systematically investigated fusions in 9,624 tumors across 33 cancer types using multiple fusion calling tools. We identified a total of 25,664 fusions, with a 63% validation rate. Integration of gene expression, copy number, and fusion annotation data revealed that fusions involving oncogenes tend to exhibit increased expression, whereas fusions involving tumor suppressors have the opposite effect. For fusions involving kinases, we found 1,275 with an intact kinase domain, the proportion of which varied significantly across cancer types. Our study suggests that fusions drive the development of 16.5% of cancer cases and function as the sole driver in more than 1% of them. Finally, we identified druggable fusions involving genes such as TMPRSS2, RET, FGFR3, ALK, and ESR1 in 6.0% of cases, and we predicted immunogenic peptides, suggesting that fusions may provide leads for targeted drug and immune therapy
Effects of ertugliflozin on kidney composite outcomes, renal function and albuminuria in patients with type 2 diabetes mellitus: an analysis from the randomised VERTIS CV trial
Aims/hypothesis In previous work, we reported the HR for the risk (95% CI) of the secondary kidney composite endpoint (time
to first event of doubling of serum creatinine from baseline, renal dialysis/transplant or renal death) with ertugliflozin compared
with placebo as 0.81 (0.63, 1.04). The effect of ertugliflozin on exploratory kidney-related outcomes was evaluated using data
from the eValuation of ERTugliflozin effIcacy and Safety CardioVascular outcomes (VERTIS CV) trial (NCT01986881).
Methods Individuals with type 2 diabetes mellitus and established atherosclerotic CVD were randomised to receive ertugliflozin
5 mg or 15 mg (observations from both doses were pooled), or matching placebo, added on to existing treatment. The kidney
composite outcome in VERTIS CV (reported previously) was time to first event of doubling of serum creatinine from baseline,
renal dialysis/transplant or renal death. The pre-specified exploratory composite outcome replaced doubling of serum creatinine
with sustained 40% decrease from baseline in eGFR. In addition, the impact of ertugliflozin on urinary albumin/creatinine ratio
(UACR) and eGFR over time was assessed.
Results A total of 8246 individuals were randomised and followed for a mean of 3.5 years. The exploratory kidney composite
outcome of sustained 40% reduction from baseline in eGFR, chronic kidney dialysis/transplant or renal death occurred at a lower event
rate (events per 1000 person-years) in the ertugliflozin group than with the placebo group (6.0 vs 9.0); the HR (95% CI) was 0.66
(0.50, 0.88). At 60 months, in the ertugliflozin group, placebo-corrected changes from baseline (95% CIs) in UACR and eGFR were
−16.2% (−23.9, −7.6) and 2.6 ml min−1 [1.73 m]−2 (1.5, 3.6), respectively. Ertugliflozin was associated with a consistent decrease in
UACR and attenuation of eGFR decline across subgroups, with a suggested larger effect observed in the macroalbuminuria and
Kidney Disease: Improving Global Outcomes in Chronic Kidney Disease (KDIGO CKD) high/very high-risk subgroups.
Conclusions/interpretation Among individuals with type 2 diabetes and atherosclerotic CVD, ertugliflozin reduced the risk for
the pre-specified exploratory composite renal endpoint and was associated with preservation of eGFR and reduced UACR.
Trial registration ClinicalTrials.gov NCT0198688
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