2,112 research outputs found
Relation between space-time inversion and particle-antiparticle symmetry and the microscopic essence of special relativity
After analyzing the implication of investigations on the C, P and T
transformations since 1956, we propose that there is a basic symmetry in
particle physics. The combined space-time inversion is equivalent to
particle-antiparticle transformation, denoted by . It is shown
that the relativistic quantum mechanics and quantum field theory do contain
this invariance explicitly or implicitly. In particular, (a) the appearance of
negative energy or negative probability density in single particle theory --
corresponding to the fact of existence of antiparticle, (b) spin- statistics
connection, (c) CPT theorem, (d) the Feynman propagator are linked together via
this symmetry. Furthermore, we try to derive the main results of special
relativity, especially, (e) the mass-energy relation, (f) the Lorentz
transformation by this one ``relativistic'' postulate and some
``nonrelativistic'' knowledge.Comment: 29 pages, Latex, 1 figur
Mean Response Models of Repeated Measurements in Presence of Varying Effectiveness Onset
Repeated measurements are often collected over time to evaluate treatment efficacy in clinical trials. Most of the statistical models of the repeated measurements have been focusing on their mean response as function of time. These models usually assume that the treatment has persistent effect of constant additivity or multiplicity on the mean response functions throughout the observation period of time. In reality, however, such assumption may be confounded by the potential existence of the so-called effectiveness action onset, although they are often unobserved or difficult to obtain. Instead of including nonparametric time-varying coefficients in the mean response models, we propose and study some semiparametric mean response models to accommodate such effectiveness times. Our methodologies will be demonstrated by a real randomised clinical trial data
Semiparametric Regression Analysis of Mean Residual Life with Censored Survival Data
As a function of time t, mean residual life is the remaining life expectancy of a subject given survival up to t. The proportional mean residual life model, proposed by Oakes & Dasu (1990), provides an alternative to the Cox proportional hazards model to study the association between survival times and covariates. In the presence of censoring, we develop semiparametric inference procedures for the regression coefficients of the Oakes-Dasu model using martingale theory for counting processes. We also present simulation studies and an application to the Veterans\u27 Administration lung cancer data
Spin transfer in a ferromagnet-quantum dot and tunnel barrier coupled Aharonov-Bohm ring system with Rashba spin-orbit interactions
The spin transfer effect in ferromagnet-quantum dot (insulator)-ferromagnet
Aharonov-Bohm (AB) ring system with Rashba spin-orbit (SO) interactions is
investigated by means of Keldysh nonequilibrium Green function method. It is
found that both the magnitude and direction of the spin transfer torque (STT)
acting on the right ferromagnet electrode can be effectively controlled by
changing the magnetic flux threading the AB ring or the gate voltage on the
quantum dot. The STT can be greatly augmented by matching a proper magnetic
flux and an SO interaction at a cost of low electrical current. The STT,
electrical current, and spin current are uncovered to oscillate with the
magnetic flux. The present results are expected to be useful for information
storage in nanospintronics.Comment: 17pages, 7figure
Estimating a Treatment Effect with Repeated Measurements Accounting for Varying Effectiveness Duration
To assess treatment efficacy in clinical trials, certain clinical outcomes are repeatedly measured for same subject over time. They can be regarded as function of time. The difference in their mean functions between the treatment arms usually characterises a treatment effect. Due to the potential existence of subject-specific treatment effectiveness lag and saturation times, erosion of treatment effect in the difference may occur during the observation period of time. Instead of using ad hoc parametric or purely nonparametric time-varying coefficients in statistical modeling, we first propose to model the treatment effectiveness durations, which are the varying time intervals between the lag and saturation times. Then some mean response models are used to include such treatment effectiveness durations. Our methodologies are demonstrated by simulations and an application to the dataset of a landmark HIV/AIDS clinical trial of short-course nevirapine against mother-to-child HIV vertical transmission during labour and delivery
SheetCopilot: Bringing Software Productivity to the Next Level through Large Language Models
Computer end users have spent billions of hours completing daily tasks like
tabular data processing and project timeline scheduling. Most of these tasks
are repetitive and error-prone, yet most end users lack the skill to automate
these burdensome works. With the advent of large language models (LLMs),
directing software with natural language user requests become a reachable goal.
In this work, we propose a SheetCopilot agent that takes natural language task
and control spreadsheet to fulfill the requirements. We propose a set of atomic
actions as an abstraction of spreadsheet software functionalities. We further
design a state machine-based task planning framework for LLMs to robustly
interact with spreadsheets. We curate a representative dataset containing 221
spreadsheet control tasks and establish a fully automated evaluation pipeline
for rigorously benchmarking the ability of LLMs in software control tasks. Our
SheetCopilot correctly completes 44.3\% of tasks for a single generation,
outperforming the strong code generation baseline by a wide margin. Our project
page:https://sheetcopilot.github.io/.Comment: Accepted to NeurIPS 202
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