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Full-Text Articles in Life Sciences

Complex Dynamics And Multistability In A Damped Harmonic Oscillator With Delayed Negative Feedback, Sue Ann Campbell, Jacques Bélair, Toru Ohira, John Milton Dec 1995

Complex Dynamics And Multistability In A Damped Harmonic Oscillator With Delayed Negative Feedback, Sue Ann Campbell, Jacques Bélair, Toru Ohira, John Milton

WM Keck Science Faculty Papers

A center manifold reduction and numerical calculations are used to demonstrate the presence of limit cycles, two-tori, and multistability in the damped harmonic oscillator with delayed negative feedback. This model is the prototype of a mechanical system operating with delayed feedback. Complex dynamics are thus seen to arise in very plausible and commonly occurring mechanical and neuromechanical feedback systems.


Static Forces And Moments Generated In The Insect Leg: Comparison Of A Three-Dimensional Musculo-Skeletal Computer Model With Experimental Measurements, Robert J. Full, Anna N. Ahn Jun 1995

Static Forces And Moments Generated In The Insect Leg: Comparison Of A Three-Dimensional Musculo-Skeletal Computer Model With Experimental Measurements, Robert J. Full, Anna N. Ahn

All HMC Faculty Publications and Research

As a first step towards the integration of information on neural control, biomechanics and isolated muscle function, we constructed a three-dimensional musculo-skeletal model of the hind leg of the death-head cockroach Blaberus discoidalis. We tested the model by measuring the maximum force generated in vivo by the hind leg of the cockroach, the coxa-femur joint angle and the position of this leg during a behavior, wedging, that was likely to require maximum torque or moment production. The product of the maximum force of the leg and its moment arm yielded a measured coxa-femur joint moment for wedging behavior. The …


A High-Bandwidth Frequency-Domain Photon Migration Instrument For Clinical Use, Steen J. Madsen, Eric R. Anderson, Richard C. Haskell, Bruce J. Tromberg May 1995

A High-Bandwidth Frequency-Domain Photon Migration Instrument For Clinical Use, Steen J. Madsen, Eric R. Anderson, Richard C. Haskell, Bruce J. Tromberg

All HMC Faculty Publications and Research

We have developed a high-bandwidth frequency-domain photon migration (FDPM) instrument which is capable of noninvasively determining the optical properties of biological tissues in near-real-time. This portable, inexpensive, diode-based instrument is unique in the sense that we employ direct diode laser modulation and avalanche photodiode detection. Diffusion models were used to extract the optical properties (absorption and transport scattering coefficients)of tissue-simulating solutions.from the 300 kHz to I GHz photon density wave data.


Dynamic Diseases In Neurology And Psychiatry, John Milton, Deborah Black Mar 1995

Dynamic Diseases In Neurology And Psychiatry, John Milton, Deborah Black

WM Keck Science Faculty Papers

Thirty-two (32) periodic diseases of the nervous system are identified in which symptoms and/or signs recur. In 10/32, the recurrence of a symptom complex is one of the defining features of the illness, whereas in 22/32 oscillatory signs occur in the setting of an ongoing nervous system disorder. We discuss the possibility that these disorders may be dynamic diseases.


Dynamical Disease: Identification, Temporal Aspects And Treatment Strategies For Human Illness, Jacques Bélair, Leon Glass, Uwe An Der Heiden, John Milton Mar 1995

Dynamical Disease: Identification, Temporal Aspects And Treatment Strategies For Human Illness, Jacques Bélair, Leon Glass, Uwe An Der Heiden, John Milton

WM Keck Science Faculty Papers

Dynamical diseases are characterized by sudden changes in the qualitative dynamics of physiological processes, leading to abnormal dynamics and disease. Thus, there is a natural matching between the mathematical field of nonlinear dynamics and medicine. This paper summarizes advances in the study of dynamical disease with emphasis on a NATO Advanced Research Workshop held in Mont Tremblant, Quebec, Canada in February 1994. We describe the international effort currently underway to identify dynamical diseases and to study these diseases from a perspective of nonlinear dynamics. Linear and nonlinear time series analysis combined with analysis of bifurcations in dynamics are being used …


Bones Of Puffinus Lherminieri Lesson (Aves: Procellaridae) And Two Other Vertebrates From Cueva Del Agua, Mona Isalnd, Puerto Rico (West Indies), Angel M. Nieves-Rivera, John M. Mylroie, Donald A. Mcfarlane Jan 1995

Bones Of Puffinus Lherminieri Lesson (Aves: Procellaridae) And Two Other Vertebrates From Cueva Del Agua, Mona Isalnd, Puerto Rico (West Indies), Angel M. Nieves-Rivera, John M. Mylroie, Donald A. Mcfarlane

WM Keck Science Faculty Papers

From a dive in Cueva del Agua, Mona Island, Puerto Rico, twelve un-mineralized bones of Puffinus Lherminieri Lesson, one of Cyclura stejnegeri Stejneger, and one of Moormops blainvilii Leach were collected. The subfossil evidence confirms that P. Lherminieri was a common species on Mona Island. Cyclura stejnegeri and M. blainvilii probably became trapped and died in the pool chamber.