Dissolved concentrations of four forms of arsenic: arsenite, arsenate, monomethylarsenic, and dimethylarsenic, were measured in the Patuxent River Estuary near Benedict, Maryland, over two annual cycles. In each year, total arsenic concentrations peaked in the summer, in lateJuly and August, while minimum concentrations occurred in winter. Except in late winter, arsenate was a predominant form ...

Identifying the authorship either of an anonymous or a doubtful document constitutes a cornerstone for automatic forensic applications. Moreover, it is a challenging task for both humans and computers. Clustering documents according to the linguistic style of the authors who wrote them has been a task little studied by the research community. In order to address this problem, PAN Evaluation Fra...

Groups of the Guatemalan black howler monkey (Alouatta pigra) in a fragmented northern Guatemalan cloud forest in the Sierra Yalijux were analyzed for group composition and size using an ornithological census technique. Audio and visual records were combined to estimate each group’s home range size. The 361 observations in 2002 estimated 50 individuals in seven groups. Two home range classes we...

This paper shows that an integrable approximation of the spring pendulum, when tuned to be in 1 : 1 : 2 resonance, has monodromy. The stepwise precession angle of the swing plane of the resonant spring pendulum is shown to be a rotation number of the integrable approximation. Due to the monodromy, this rotation number is not a globally defined function of the integrals. In fact at lowest order ...

The facility layout problem is concerned with finding the most efficient arrangement of a given number of departments with unequal area requirements within a facility. The facility layout problem is a hard problem, and therefore, exact solution methods are only feasible for small or greatly restricted problems. In this paper, we propose a spring-embedding approach that unlike previous approache...

Dr. Constance E. Ruhl is an Epidemiologist at Social & Scientific Systems, Inc., Silver Spring, MD. Dr. Jeanne M. Clark is a Professor of Medicine and Epidemiology and Director of the Division of General Internal Medicine at The Johns Hopkins University, Baltimore, MD. Dr. James E. Everhart was Chief of the Epidemiology and Clinical Trials Branch in the Division of Digestive Diseases and Nutrit...

The spring-loaded inverted pendulum (SLIP), or monopedal hopper, is an archetypal model for running in numerous animal species. Although locomotion is generally considered a complex task requiring sophisticated control strategies to account for coordination and stability, we show that stable gaits can be found in the SLIP with both linear and "air" springs, controlled by a simple fixed-leg rese...

In this paper, we present our implementation of physically-based simulation of hair strips. We used a mass-spring model followed by a hybrid approach where particle systems and the method of clustering of hair strands are employed. All the forces related to springs are implemented: gravity, repulsions from collisions (head and ground), absorption (ground only), frictions (ground and air), inter...

The spring pendulum in resonance is a model system for formal reduction to one degree of freedom, where some symmetry (reversibility) is maintained. The reduction can be handled by equivariant singularity theory with a distinguished parameter, yielding an integrable approximation of the Poincar e map. This makes a concise description of certain bifurcations possible. The computation of reparame...

Digital watermarking techniques have been proposed to protect the copyright of multimedia data. Robustness against geometric distortion is one of the most important issues to be solved to increase the robustness of digital image watermarking systems. Such attacks are very simple to implement, so they can defeat most existing watermarking algorithms without causing serious perceptual distortion....