Douglas E Jones
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- Jones, D., & Jones, D. (0). Deaf and hearing parents' perceptions of family functioning. Nursing research, 44(2).More infoThe purpose of this descriptive study was to compare Deaf and hearing parents' perceptions of family functioning. The Feetham Family Functioning Survey (FFFS) was administered in American Sign Language on videotape to 40 Deaf mothers and fathers and in its original written English form to a comparison group of 40 hearing mothers and fathers. There were no statistically significant differences in FFFS discrepancy (D) subscale scores among Deaf versus hearing parents. Deaf and hearing parents' scores on the FFFS importance (C) subscale items were used to identify the 10 areas of family functioning most important to the parents. Agreement among Deaf and hearing parents was noted on 7 of 10 items ranked as most important. One difference was that Deaf parents ranked leisure/recreational activities as more important than hearing parents.
- Jones, D., Kolesik, M., Wright, E. M., Andreasen, J., Brown, J. M., Carlson, D. R., & Jones, D. (2012). Space-time resolved simulation of femtosecond nonlinear light-matter interactions using a holistic quantum atomic model: application to near-threshold harmonics. Optics express, 20(14).More infoWe introduce a new computational approach for femtosecond pulse propagation in the transparency region of gases that permits full resolution in three space dimensions plus time while fully incorporating quantum coherent effects such as high-harmonic generation and strong-field ionization in a holistic fashion. This is achieved by utilizing a one-dimensional model atom with a delta-function potential which allows for a closed-form solution for the nonlinear optical response due to ground-state to continuum transitions. It side-steps evaluation of the wave function, and offers more than one hundred-fold reduction in computation time in comparison to direct solution of the atomic Schrödinger equation. To illustrate the capability of our new computational approach, we apply it to the example of near-threshold harmonic generation in Xenon, and we also present a qualitative comparison between our model and results from an in-house experiment on extreme ultraviolet generation in a femtosecond enhancement cavity.
- Jones, D., Carlson, D. R., Lee, J., Mongelli, J., Wright, E. M., & Jones, D. (2011). Intracavity ionization and pulse formation in femtosecond enhancement cavities. Optics letters, 36(15).More infoWe experimentally and numerically investigate the intracavity ionization of a dilute gas target by an ultrashort pulse inside a femtosecond enhancement cavity. Numerical simulations detail how the dynamic ionization of the gas target limits the achievable peak intensity of the evolving intracavity pulse beyond that of linear cavity losses, setting a constraint on the strength of the nonlinear interaction that can be sustained in such optical cavities. Experimental measurements combined with numerical simulations predict ionization levels in a femtosecond enhancement cavity for the first time. We demonstrate how the resonant response of the femtosecond enhancement cavity can itself be used as a sensitive probe of optical nonlinearities at high intensities.
- Jones, D., Wu, T., Kieu, K., Peyghambarian, N., & Jones, D. (2011). Low noise erbium fiber fs frequency comb based on a tapered-fiber carbon nanotube design. Optics express, 19(6).More infoWe report on a low noise all-fiber erbium fs frequency comb based on a simple and robust tapered-fiber carbon nanotube (tf-CNT) design. We mitigate dominant noise sources to show that the free-running linewidth of the carrier-envelope offset frequency (fceo) can be comparable to the best reported performance to date for fiber-based frequency combs. A free-running fceo linewidth of ~20 kHz is demonstrated, corresponding to an improvement of ~30 times over previous work based on a CNT mode-locked fiber laser [Opt. Express 18, 1667 (2010)]. We also demonstrate the use of an acousto-optic modulator external to the laser cavity to stabilize fceo, enabling a 300 kHz feedback control bandwidth. The offset frequency is phase-locked with an in-loop integrated phase noise of ~0.8 rad from 10Hz to 400kHz. We show a resolution-limited linewidth of ~1 Hz, demonstrating over 90% of the carrier power within the coherent fceo signal. The results demonstrate that the relatively simple tf-CNT fiber laser design can provide a compact, robust and high-performance fs frequency comb.
- Jones, D., Ochman, H., & Jones, D. (2000). Evolutionary dynamics of full genome content in Escherichia coli. The EMBO journal, 19(24).More infoThe evolutionary history of the entire Escherichia coli chromosome was traced by examining the distribution of the approximately 4300 open reading frames (ORFs) from E.coli MG1655 among strains of known genealogical relationships. Using this framework to deduce the incidence of gene transfer and gene loss, a total of 67 events-37 additions and 30 deletions-were required to account for the distribution of all genes now present in the MG1655 chromosome. Nearly 90% of the ORFs were common to all strains examined, but, given the variation in gene content and chromosome size, strains can contain well over a megabase of unique DNA, conferring traits that distinguish them from other members of the species. Moreover, strains vary widely in their frequencies of deletions, which probably accounts for the variation in genome size within the species.
- Jones, D., Parsons, L. C., Crosby, L. J., Perlis, M., Britt, T., & Jones, D. (1997). Longitudinal sleep EEG power spectral analysis studies in adolescents with minor head injury. Journal of neurotrauma, 14(8).More infoPower spectral analysis (PSA) was used to evaluate the longitudinal overnight electroencephalographic (EEG) sleep recordings of eight subjects, between the ages of 15 and 19 years, who had sustained a minor head injury (MHI). Recordings occurred within 72 h, 6 weeks, and 12 weeks following MHI. A conditioning night preceded the first study night during which EEG electrodes were in place and subjects slept at least 7.5 h with a mean sleep efficiency of 91%. PSA was performed on four channels of EEG data recorded from fronto-temporal (F3-T3, F4-T4), and temporal (T3-T5, T4-T6) electrodes. The three waveforms associated with sleep, Delta, Theta, and Alpha-1 were all significantly elevated within 72 h post-MHI. Over time all wave forms decreased in mean log power. Theta in rapid eye movement (REM) sleep Cycle 1 decreased significantly within 6 weeks postinjury. The greatest number of significant changes, over the 12-week period were recorded during the non-REM (NREM) sleep. Changes included (1) significant decreases in mean log power of Theta and Alpha-1 in Cycle 1 from fronto-temporal leads; (2) significant decreases in Delta, Theta, and Alpha-1 in Cycle 2 from fronto-temporal leads, and (3) significant decreases in Delta and Theta for consistency during Cycle 2 from temporal leads. The intrusion of Theta into the first REM cycle within 6 weeks and its subsequent decrease within 6 weeks suggested the initiation of recovery toward baseline values. This was followed by decreased levels of Theta power during NREM Cycles 1 and 2, and Delta power in Cycle 2, both of which approached their lowest levels within 12 wks. The decrease in Alpha-1 power occurred last. Alpha-1 remained elevated through both Cycles 1 and 2 of the 6th week and then showed a precipitous decrease between the sixth and twelfth week. These findings suggested that following MHI, the brain has a specific sequence of recovery as illustrated by Delta, Theta, and Alpha-1 powers requiring different time frames to reach their lowest levels.
- Jones, D., & Jones, D. (1996). Deaf and hearing mothers' interactions with normally hearing infants and toddlers. Journal of pediatric nursing, 11(1).More infoThe purpose of this study was to compare the interactions between Deaf mothers and their normally hearing infants and toddlers with the interactions between hearing mothers and their normally hearing infants and toddlers. The Nursing Child Assessment Teaching Scale (NCATS), modified to credit Deaf mothers and their children for both spoken and signed communications, was used to assess mother-child interactions. There were no statistically significant differences in scores on the NCATS Parent subscales, NCATS Child subscales, or in total NCATS scores of the Deaf mother/child dyads compared with the hearing mother/child dyads. Implications for clinical practice are discussed.
- Jones, D., Rodriguez, J. A., & Jones, D. (1996). Foster parents' early adaptation to the placement of a child with developmental disabilities in their home. Journal of pediatric nursing, 11(2).More infoEight foster parents of children with developmental disabilities (DD) were interviewed about their early adaptation to placement of the child in their homes. Analysis using a grounded theory methodology showed important adaptations in the physiological, role function, interdependence, and self-concept modes of adaptation. Parents described less attention to their own physical health, dominance of the parenting role over all other roles, decreased social interactions, and a sense of personal satisfaction in response to placement of a child with DD in their homes. Implications for nursing practice are included.
- Jones, D., Yoshino, M. T., Carmody, R., Fajardo, L. L., Seeger, J., & Jones, D. (1992). Diagnostic performance of teleradiology in cervical spine fracture detection. Investigative radiology, 27(1).More infoThis study was done to assess the diagnostic accuracy of high-resolution (5 lp/mm) teleradiology for detecting cervical spine fractures. Single radiographs from 25 patients with and 25 patients without cervical spine fractures were transmitted between two units of our teleradiology system (Dupont DTR 2000) located 5 miles apart. Each image was examined by four readers. Fracture detection accuracy was assessed by generating receiver operating characteristic (ROC) curves and comparing the areas under each reader's curves for original and transmitted images. Two readers had statistically significant better fracture detection using nontransmitted images, whereas two had no significant differences in accuracy. The authors conclude that high resolution in and of itself is not adequate for fracture detection, and that issues concerning image contrast manipulation also will have to be addressed before teleradiology systems can be used for clinical cervical spine fracture screening.
- Jones, D., Barrowcliffe, M. P., Otto, C., & Jones, D. (1988). Pulmonary clearance of 99mTc-DTPA: influence of background activity. Journal of applied physiology (Bethesda, Md. : 1985), 64(3).More infoWe examined the effect of intravascular and tissue accumulation of tracer when measuring pulmonary clearance of sodium pertechnetate-labeled diethylenetriamine pentaacetate (99mTc-DTPA). Pigs were intubated with endobronchial tubes, permitting deposition of an aerosol of 99mTc-DTPA only into the left lung. Scintillation detectors recorded radioactivity separately from one thigh and from the lung and chest wall on the left and right side. 99mTc-DTPA was given intravenously after 30 min, so that the chest counts from the left lung could be corrected for background activity in either the right lung or the thigh. The uncorrected clearance half time (t1/2) mean +/- SE from the left chest was 118.5 +/- 14.4 min. When corrected for background activity in the right chest, the t1/2 was 82.1 +/- 10.5 min, and when corrected for background activity in the thigh, the t1/2 was 80.9 +/- 10.6 min. There was no significant difference between t1/2 corrected by the measurements from the right chest or the thigh, and in four of five animals the corrected t1/2 by either method was significantly different from the uncorrected t1/2 (P less than 0.05). There was no correlation between the uncorrected t1/2 and the magnitude of the required correction. We conclude that correction for intravascular and tissue accumulation of tracer is an important refinement of the technique and can easily be accomplished by measuring accumulation of tracer in the thigh.
- Jones, D., Armstrong, E. P., Nako, N., Plezia, P. M., Kramer, T. H., & Jones, D. (1987). Steady-state pharmacokinetics of two sustained-release theophylline products during once-daily and twice-daily dosing. Clinical pharmacy, 6(10).