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Search Results: 1 - 10 of 147265 matches for " Brenda B. Jackson "
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Development and Validation of a Smartphone Heart Rate Acquisition Application for Health Promotion and Wellness Telehealth Applications
Mathew J. Gregoski,Martina Mueller,Alexey Vertegel,Aleksey Shaporev,Brenda B. Jackson,Ronja M. Frenzel,Sara M. Sprehn,Frank A. Treiber
International Journal of Telemedicine and Applications , 2012, DOI: 10.1155/2012/696324
Abstract: Objective. Current generation smartphones' video camera technologies enable photoplethysmographic (PPG) acquisition and heart rate (HR) measurement. The study objective was to develop an Android application and compare HRs derived from a Motorola Droid to electrocardiograph (ECG) and Nonin 9560BT pulse oximeter readings during various movement-free tasks. Materials and Methods. HRs were collected simultaneously from 14 subjects, ages 20 to 58, healthy or with clinical conditions, using the 3 devices during 5-minute periods while at rest, reading aloud under observation, and playing a video game. Correlation between the 3 devices was determined, and Bland-Altman plots for all possible pairs of devices across all conditions assessed agreement. Results. Across conditions, all device pairs showed high correlations. Bland-Altman plots further revealed the Droid as a valid measure for HR acquisition. Across all conditions, the Droid compared to ECG, 95% of the data points (differences between devices) fell within the limits of agreement. Conclusion. The Android application provides valid HRs at varying levels of movement free mental/perceptual motor exertion. Lack of electrode patches or wireless sensor telemetric straps make it advantageous for use in mobile-cell-phone-delivered health promotion and wellness programs. Further validation is needed to determine its applicability while engaging in physical movement-related activities. 1. Introduction Many cellular phones now possess high-speed data transmission capabilities (e.g., 3G, 4G) and have embedded microprocessors (e.g., Bluetooth, ANT) with the capability to wirelessly connect to external devices. As a result, cell phones offer several advantages over desktop or laptop computers in telemonitoring-related applications such as higher population penetration, increased privacy, lower cost to purchase, easier ability to transport, and overall increased personal convenience of use [1, 2]. Cell phones are widely used in telemonitoring serving as a conduit for receiving biohealth information from portable medical devices (e.g., blood pressure, glucose and pulse oximeter monitors, weight scales) and mobile sensors (e.g., physical activity; accelerometer counts, heart rate, respiration rate, pulse pressure via chest- or armbands, and wireless electrodes). Once cell phones have received the pertinent information, it is microprocessed, encrypted, and the data packets are transferred to some form of localized or web-based server for secondary processing. At the server level, the data packets are organized into a
Depressive-like behavioral response of adult male rhesus monkeys during routine animal husbandry procedure
Michael B. Hennessy,Brenda McCowan
Frontiers in Behavioral Neuroscience , 2014, DOI: 10.3389/fnbeh.2014.00309
Abstract: Social isolation is a major risk factor for the development of depressive illness; yet, no practical nonhuman primate model is available for studying processes involved in this effect. In a first study, we noted that adult male rhesus monkeys housed individually indoors occasionally exhibited a hunched, depressive-like posture. Therefore, Study 2 investigated the occurrence of a hunched posture by adult males brought from outdoor social groups to indoor individual housing. We also scored two other behaviors—lying on the substrate and day time sleeping—that convey an impression of depression. During the first week of observation following individual housing, 18 of 26 adult males exhibited the hunched posture and 21 of 26 displayed at least one depressive-like behavior. Over 2 weeks, 23 of 26 males showed depressive-like behavior during a total of only 20 min observation. Further, the behavior during the first week was positively related to the level of initial response to a maternal separation procedure experienced in infancy. In Study 3, more than half of 23 adult males of a new sample displayed depressive-like behavior during 10 min of observation each of Weeks 7–14 of individual housing. The surprisingly high frequency of depressive-like behavior in Studies 2 and 3 may have been due to recording behavior via camera with no human in the room to elicit competing responses. These results suggest that a common animal husbandry procedure might provide a practical means for examining effects of social isolation on depression-related endpoints in a nonhuman primate. The findings also suggest that trait-like differences in emotional responsiveness during separation in infancy may predict differences in responsiveness during social isolation in adulthood.
Quadrupole collective modes in trapped finite-temperature Bose-Einstein condensates
B. Jackson,E. Zaremba
Physics , 2002, DOI: 10.1103/PhysRevLett.88.180402
Abstract: Finite temperature simulations are used to study quadrupole excitations of a trapped Bose-Einstein condensate. We focus specifically on the m=0 mode, where a long-standing theoretical problem has been to account for an anomalous variation of the mode frequency with temperature. We explain this behavior in terms of the excitation of two separate modes, corresponding to coupled motion of the condensate and thermal cloud. The relative amplitudes of the modes depends sensitively on the temperature and on the frequency of the harmonic drive used to excite them. Good agreement with experiment is found for appropriate drive frequencies.
Accidental suppression of Landau damping of the transverse breathing mode in elongated Bose-Einstein condensates
B. Jackson,E. Zaremba
Physics , 2002, DOI: 10.1103/PhysRevLett.89.150402
Abstract: We study transverse radial oscillations of an elongated Bose-Einstein condensate using finite temperature simulations, in the context of a recent experiment at ENS. We demonstrate the existence of a mode corresponding to an in-phase collective oscillation of both the condensate and thermal cloud. Excitation of this mode accounts for the very small damping rate observed experimentally, and we find excellent quantitative agreement between experiment and theory. In contrast to other condensate modes, interatomic collisions are found to be the dominant damping mechanism in this case.
Transverse modes of a cigar-shaped Bose-Einstein condensate
B. Jackson,E. Zaremba
Physics , 2002,
Abstract: We discuss the collective modes in a harmonically trapped, highly-elongated Bose condensed gas. The transverse breathing mode exhibits a number of interesting features, such as the insensitivity of the condensate mode frequency to the interaction strength, and the closeness of the frequency to that of the non-condensed thermal cloud in the collisionless limit. Using finite temperature simulations, we show that these features are responsible for the very small damping rate observed experimentally. Our results for the temperature dependence of the damping rate and frequency shift are in excellent agreement with experiment. We also demonstrate that the unusually small damping rate does not arise for the $m=2$ mode or for more isotropic trap potentials, suggesting further possible experimental tests of our theory.
Finite-temperature simulations of the scissors mode in Bose-Einstein condensed gases
B. Jackson,E. Zaremba
Physics , 2001, DOI: 10.1103/PhysRevLett.87.100404
Abstract: The dynamics of a trapped Bose-condensed gas at finite temperatures is described by a generalized Gross-Pitaevskii equation for the condensate order parameter and a semi-classical kinetic equation for the thermal cloud, solved using $N$-body simulations. The two components are coupled by mean fields as well as collisional processes that transfer atoms between the two. We use this scheme to investigate scissors modes in anisotropic traps as a function of temperature. Frequency shifts and damping rates of the condensate mode are extracted, and are found to be in good agreement with recent experiments.
Dynamical Simulations of Trapped Bose Gases at Finite Temperatures
B. Jackson,E. Zaremba
Physics , 2001,
Abstract: In this paper, we develop a numerical procedure for investigating the dynamics of trapped Bose gases based on the ZGN theory. The dynamical equations used consist of a generalized Gross-Pitaevskii equation for the condensate order parameter and a semiclassical kinetic equation for the thermal cloud. The former is solved using a fast Fourier transform split-operator technique while the Boltzmann equation is treated by means of N-body simulations. The two components are coupled by mean fields as well as collisional processes that transfer atoms between the two. This scheme has been applied to a model equilibration problem, dipole oscillations in isotropic traps and scissors modes in anisotropic traps. In the case of the latter, the frequencies and damping rates of the condensate mode have been extracted from the simulations for a wide range of temperatures. Good agreement with recent experiments has been found.
Landau damping in trapped Bose-condensed gases
B. Jackson,E. Zaremba
Physics , 2003, DOI: 10.1088/1367-2630/5/1/388
Abstract: We study Landau damping in dilute Bose-Einstein condensed gases in both spherical and prolate ellipsoidal harmonic traps. We solve the Bogoliubov equations for the mode spectrum in both of these cases, and calculate the damping by summing over transitions between excited quasiparticle states. The results for the spherical case are compared to those obtained in the Hartree-Fock approximation, where the excitations take on a single-particle character, and excellent agreement between the two approaches is found. We have also taken the semiclassical limit of the Hartree-Fock approximation and obtain a novel expression for the Landau damping rate involving the time dependent self-diffusion function of the thermal cloud. As a final approach, we study the decay of a condensate mode by making use of dynamical simulations in which both the condensate and thermal cloud are evolved explicitly as a function of time. A detailed comparison of all these methods over a wide range of sample sizes and trap geometries is presented.
Modelling Bose-condensed gases at finite temperatures with $N$-body simulations
B. Jackson,E. Zaremba
Physics , 2002, DOI: 10.1103/PhysRevA.66.033606
Abstract: We consider a model of a dilute Bose-Einstein condensed gas at finite temperatures, where the condensate coexists in a trap with a cloud of thermal excitations. Within the ZGN formalism, the dynamics of the condensate is described by a generalized Gross-Pitaevskii equation, while the thermal cloud is represented by a semiclassical kinetic equation. Our numerical approach simulates the kinetic equation using a cloud of representative test particles, while collisions are treated by means of a Monte Carlo sampling technique. A full 3D split-operator Fast Fourier Transform method is used to evolve the condensate wavefunction. We give details regarding the numerical methods used and discuss simulations carried out to test the accuracy of the numerics. We use this scheme to simulate the monopole mode in a spherical trap. The dynamical coupling between the condensate and thermal cloud is responsible for frequency shifts and damping of the condensate collective mode. We compare our results to previous theoretical approaches, not only to confirm the reliability of our numerical scheme, but also to check the validity of approximations which have been used in the past.
Safe Staffing in Massachusetts: A Year of Legislative Action
Linda Curtin,Gail B. Gall,Brenda Vigue
Online Journal of Issues in Nursing , 2006,
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