382,677 research outputs found
Semiparametric estimation of a panel data proportional hazards model with fixed effects
This paper considers a panel duration model that has a proportional hazards specification
with fixed effects. The paper shows how to estimate the baseline and integrated
baseline hazard functions without assuming that they belong to known, finitedimensional
families of functions. Existing estimators assume that the baseline hazard
function belongs to a known parametric family. Therefore, the estimators presented here
are more general than existing ones. This paper also presents a method for estimating
the parametric part of the proportional hazards model with dependent right censoring,
under which the partial likelihood estimator is inconsistent. The paper presents some
Monte Carlo evidence on the small sample performance of the new estimators
Bioaffinity detection of pathogens on surfaces
The demand for improved technologies capable of rapidly detecting pathogens with high sensitivity and selectivity in complex environments continues to be a significant challenge that helps drive the development of new analytical techniques. Surface-based detection platforms are particularly attractive as multiple bioaffinity interactions between different targets and corresponding probe molecules can be monitored simultaneously in a single measurement. Furthermore, the possibilities for developing new signal transduction mechanisms alongside novel signal amplification strategies aremuchmore varied. In this article, we describe some of the latest advances in the use of surface bioaffinity detection of pathogens. Three major sections will be discussed: (i) a brief overview on the choice of probe molecules such as antibodies, proteins and aptamers specific to pathogens and surface attachment chemistries to immobilize those probes onto various substrates, (ii) highlighting examples among the current generation of surface biosensors, and (iii) exploring emerging technologies that are highly promising and likely to form the basis of the next generation of pathogenic sensors
Communication, coordination and networks
We study experimentally how the network structure and length of pre-play communication affect behavior and outcome in a multi-player coordination game with
conflicting preferences. Network structure matters but the interaction between network and time effects is more subtle. Under each time treatment, substantial variations are observed in both the rate of coordination and distribution of coordinated outcomes across networks. But, increasing the communication length improves both efficiency and equity of coordination. In all treatments, coordination is mostly explained by convergence in communication. We also identify behaviors that explain
variations in the distribution of coordinated outcomes both within and across networks
Nonparametric estimation of an additive quantile regression model
This paper is concerned with estimating the additive components of a nonparametric
additive quantile regression model. We develop an estimator that is asymptotically
normally distributed with a rate of convergence in probability of n^{-r/(2+10)} when the
additive components are r-times continuously differentiable for some r\geq2. This result
holds regardless of the dimension of the covariates and, therefore, the new estimator
has no curse of dimensionality. In addition, the estimator has an oracle property and is
easily extended to a generalized additive quantile regression model with a link function.
The numerical performance and usefulness of the estimator are illustrated by Monte
Carlo experiments and an empirical example
Effect of Diethylenetriamine and Triethylamine sensitization on the critical diameter of Nitromethane
In this work, the critical diameter for detonation was measured for Nitromethane (NM) sensitized with two different amines: Diethylenetriamine (DETA) and Triethylamine (TEA). The critical diameter in glass and polyvinylchloride tubes is found to decrease rapidly as the amount of sensitizer is increased, then increase past a critical amount of sensitizer. Thus the critical diameter reaches a minimum at a critical concentration of sensitizer. It was also found that the critical diameter is lower with DETA than with TEA
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