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Suspended sediment loads mobilized during high flow periods in rivers and streams are largely uncharacterized. In smaller and intermittent streams, a large storm may transport a majority of the annual sediment budget. Therefore monitoring techniques that can measure high suspended sediment concentrations at semi-continuous time intervals are needed. A Fiber optic In-stream Transmissometer (FIT) is presented for continuous measurement of high concentration suspended sediment in storm runoff. FIT performance and precision were demonstrated to be reasonably good for suspended sediment concentrations up to 10g/L. The FIT was compared to two commercially available turbidity devices and provided better precision and accuracy at both high and low concentrations. Both turbidity devices were unable to collect measurements at concentrat...
Background: Decreased heart rate variability (HRV) has been associated with future cardiac morbidity and mortality and is often used as a marker of altered cardiac autonomic balance in studies of health effects of airborne particulate matter. Fewer studies have evaluated associations between air pollutants and cardiac arrhythmia.Objectives: We examined relationships between cardiac arrhythmias, HRV, and exposures to airborne particulate matter.Methods: We measured HRV and arrhythmia with ambulatory electrocardiograms in a cohort panel study for up to 235 hr per participant among 50 nonsmokers with coronary artery disease who were ≥ 71 years of age and living in four retirement communities in the Los Angeles, California, Air Basin. Exposures included hourly outdoor gases, hourly traffic-related and secondary organic aerosol markers, and...
We present an algorithm for shape matching and recognition based on a generative model for how one shape can be generated by the other. This generative model allows for a class of transformations, such as affine and non-rigid transformations, and induces a similarity measure between shapes. The matching process if formulated in the EM algorithm. To have a fast algorithm and avoid local minima, we show how the EM algorithm can be approximated by using informative features, which have two key properties-invariant and representative. They are also similar to the proposal probabilities used in DDMCMC [13]. The formulation allows us to know when and why approximations can be made and justifies the use of bottom-up features, which are used in a wide range of vision problems. This integrates generative models and feature-based approaches with...
Using confidential microdata from the U.S. Census Bureau, we investigate the performance of female-owned businesses, making comparisons to male-owned businesses. Using regression estimates and a decomposition technique, we explore the role that human capital, especially through prior work experience, and financial capital play in contributing to why female-owned businesses have lower survival rates, profits, employment, and sales. We find that female-owned businesses are less successful than male-owned businesses because they have less startup capital, less business human capital acquired through prior work experience in a similar business, and less prior work experience in a family business. We also find some evidence that female business owners work fewer hours and may have different preferences for the goals of their businesses, whi...
Possible causes of the spring persistence barrier in ENSO sea surface temperature anomalies are examined using a coupled atmosphere-ocean general circulation model (CGCM). Our study indicates that the persistence barrier is significantly enhanced when both Pacific and Indian Ocean couplings are included in the CGCM, compared to the simulation that includes only the Pacific Ocean coupling. ENSO's variance, phase locking to the annual cycle, and biennial variability are also increased in the Indo-Pacific Run. Further analysis reveals that the overall amplitude of ENSO is not a primary factor in determining the strength of the persistence barrier, rather, it is the amplitude of the biennial component of ENSO affecting the barrier the most. The persistence barrier is consistently strong (weak) when biennial ENSO variability is large (small...
