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Search Results: 1 - 10 of 228879 matches for " Jennifer R. Dungan "
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The genetic basis for survivorship in coronary artery disease
Jennifer R. Dungan,Elizabeth R. Hauser
Frontiers in Genetics , 2013, DOI: 10.3389/fgene.2013.00191
Abstract: Survivorship is a trait characterized by endurance and virility in the face of hardship. It is largely considered a psychosocial attribute developed during fatal conditions, rather than a biological trait for robustness in the context of complex, age-dependent diseases like coronary artery disease (CAD). The purpose of this paper is to present the novel phenotype, survivorship in CAD as an observed survival advantage concurrent with clinically significant CAD. We present a model for characterizing survivorship in CAD and its relationships with overlapping time- and clinically-related phenotypes. We offer an optimal measurement interval for investigating survivorship in CAD. We hypothesize genetic contributions to this construct and review the literature for evidence of genetic contribution to overlapping phenotypes in support of our hypothesis. We also present preliminary evidence of genetic effects on survival in people with clinically significant CAD from a primary case-control study of symptomatic coronary disease. Identifying gene variants that confer improved survival in the context of clinically appreciable CAD may improve our understanding of cardioprotective mechanisms acting at the gene level and potentially impact patients clinically in the future. Further, characterizing other survival-variant genetic effects may improve signal-to-noise ratio in detecting gene associations for CAD.
Sentinel-2 MSI Radiometric Characterization and Cross-Calibration with Landsat-8 OLI  [PDF]
Shuang Li, Sangram Ganguly, Jennifer L. Dungan, Weile Wang, Ramakrishna R. Nemani
Advances in Remote Sensing (ARS) , 2017, DOI: 10.4236/ars.2017.62011
Abstract: Near-nadir observations by the Multispectral Instrument (MSI) onboard the Sentinel-2 and the Operational Land Imager (OLI) onboard Landsat 8 were collected during two Simultaneous Nadir Overpasses (SNO). Multispectral images with 10, 20, and 30 m resolution from a spatially uniform area in the Saharan desert were acquired for direct comparison of MSI and OLI Top- Of-Atmosphere (TOA) reflectances. This paper presents an initial radiometric cross-calibration of the 8 corresponding spectral bands of the Sentinel-2 MSI and Landsat 8 OLI sensors. With the well-calibrated Landsat 8 OLI as a reference, the comparison indicates that 6 MSI bands are consistent with OLI within 3% in terms of spectral band adjustment factors Bi . The Near-Infra-Red (NIR) and cirrus bands are exceptions. They yield radiometric differences on the order of 8% and 15% respectively. Cross-calibration results show that the radiometric difference of the 7 corresponding bands are consistent to OLI within 1% or better, except on cirrus band. A pixel-by-pixel match between the MSI and OLI observations for different land covers showed that. This initial study suggests that the red-edge band B8A of MSI can be used to replace the NIR band B08 when conducting vegetation monitoring.
Spliced Leader RNAs, Mitochondrial Gene Frameshifts and Multi-Protein Phylogeny Expand Support for the Genus Perkinsus as a Unique Group of Alveolates
Huan Zhang,David A. Campbell,Nancy R. Sturm,Christopher F. Dungan,Senjie Lin
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0019933
Abstract: The genus Perkinsus occupies a precarious phylogenetic position. To gain a better understanding of the relationship between perkinsids, dinoflagellates and other alveolates, we analyzed the nuclear-encoded spliced-leader (SL) RNA and mitochondrial genes, intron prevalence, and multi-protein phylogenies. In contrast to the canonical 22-nt SL found in dinoflagellates (DinoSL), P. marinus has a shorter (21-nt) and a longer (22-nt) SL with slightly different sequences than DinoSL. The major SL RNA transcripts range in size between 80–83 nt in P. marinus, and ~83 nt in P. chesapeaki, significantly larger than the typical ≤56-nt dinoflagellate SL RNA. In most of the phylogenetic trees based on 41 predicted protein sequences, P. marinus branched at the base of the dinoflagellate clade that included the ancient taxa Oxyrrhis and Amoebophrya, sister to the clade of apicomplexans, and in some cases clustered with apicomplexans as a sister to the dinoflagellate clade. Of 104 Perkinsus spp. genes examined 69.2% had introns, a higher intron prevalence than in dinoflagellates. Examination of Perkinsus spp. mitochondrial cytochrome B and cytochrome C oxidase subunit I genes and their cDNAs revealed no mRNA editing, but these transcripts can only be translated when frameshifts are introduced at every AGG and CCC codon as if AGGY codes for glycine and CCCCU for proline. These results, along with the presence of the numerous uncharacterized ‘marine alveolate group I' and Perkinsus-like lineages separating perkinsids from core dinoflagellates, expand support for the affiliation of the genus Perkinsus with an independent lineage (Perkinsozoa) positioned between the phyla of Apicomplexa and Dinoflagellata.
Magnetic resonance imaging (MRI): a technique to study flow an microstructure of concentrated emulsions
d'Avila, M. A.;Powell, R. L.;Phillips, R. J.;Shapley, N. C.;Walton, J. H.;Dungan, S. R.;
Brazilian Journal of Chemical Engineering , 2005, DOI: 10.1590/S0104-66322005000100006
Abstract: nuclear magnetic resonance (nmr) and magnetic resonance imaging (mri) have recently been recognized as important techniques for r&d of products and processes, as is attested by several successful applications in different areas of chemical engineering in recent years. in this article we present new experimental methods based on mri to study flow and microstructure of concentrated emulsions. the objective is to present the unique features of this noninvasive technique to accurately measure different properties of flowing particulate opaque systems. experimental results of velocity profiles, spatial distribution of droplet sizes and spatial homogeneity of an oil-in-water dispersion in a horizontal, concentric cylinder geometry using different pulse sequences are presented. the application of these techniques allowed probing important information on flow and microstructure of multiphase systems of interest in chemical engineering and food science.
Varying-G Cosmology with Type Ia Supernovae
Rutger Dungan,Harrison B. Prosper
Physics , 2009,
Abstract: The observation that Type Ia supernovae are fainter than expected given their red shifts has led to the conclusion that the expansion of the universe is accelerating. The widely accepted hypothesis is that this acceleration is caused by a cosmological constant or, more generally, some dark energy field that pervades the universe. This hypothesis presents a challenge to physics so severe that one is motivated to explore alternative explanations. In this paper, we explore whether the data from Type Ia supernovae can be explained with an idea that is almost as old as that of the cosmological constant, namely, that the strength of gravity varies on a cosmic timescale. This topic is an ideal one for investigation by an undergraduate physics major because the entire chain of reasoning from models to data analysis is well within the mathematical and conceptual sophistication of a motivated undergraduate.
Neural correlates of focused attention in cognitively normal older adults  [PDF]
Jennifer R. Bowes, Patrick Stroman, Angeles Garcia
World Journal of Neuroscience (WJNS) , 2011, DOI: 10.4236/wjns.2011.12003
Abstract: Focused attention (FA) is among the cognitive functions that decline with aging. The Stroop task was used to investigate the neural correlates underlying FA in cognitively normal older adults. Twenty-one participants underwent a novel functional magnetic resonance imaging (fMRI) verbal Stroop task paradigm. Colour words were printed in an incongruent ink colour. Series 1 consisted of four blocks “Read the word” followed by four blocks “Say the colour of the ink”; Series 2 alternated between the two conditions. Functional data were analyzed using SPM5 to detect anatomical areas with significant signal intensity differences between the conditions. Within-group analyses of the “Say the colour of the ink” minus “Read the word” contrast yielded significant activation in the left supplementary motor area, bilateral inferior frontal gyrus, bilateral precentral gyrus, left insula and right superior frontal gyrus (p < 0.05, uncorrected). These results, using verbal responses, are consistent with previous manual modality Stroop-fMRI studies in older adults. Verbal responses may provide a more suitable modality for older adults and certain patient populations.
Neural correlates of focused attention in patients with mild Alzheimer’s disease  [PDF]
Jennifer R. Bowes, Patrick Stroman, Angeles Garcia
World Journal of Neuroscience (WJNS) , 2012, DOI: 10.4236/wjns.2012.24034
Abstract: Alzheimer’s Disease (AD) is characterized by an early and significant memory impairment, and progresses to affect other cognitive domains. Impairments in Focused Attention (FA) have been observed in patients diagnosed with mild AD. A functional magnetic resonance imaging (fMRI) Stroop paradigm with verbal responses was used to investigate the neural correlates of FA in AD patients. Twenty-one patients diagnosed with mild AD performed a verbal Stroop—fMRI paradigm. Colour words were printed in an incongruent ink colour. Series 1 consisted of four blocks “Read the word” followed by four blocks “Say the colour of the ink”; Series 2 alternated between the two conditions. Functional data were analyzed using SPM5 to detect anatomical areas with significant signal intensity differences between the conditions. Within-group analyses of the colour minus word contrast yielded significant activation in the following left hemisphere regions: precentral gyrus, inferior frontal gyrus, fusiform gyrus and supplementary motor area (p < 0.05, uncorrected). Relative to cognitively normal older adults who underwent the same experimental task, Stroop performance was significantly worse in AD patients. The fMRI task yielded similar activated brain regions between the two groups. The use of verbal responses in this novel fMRI Stroop task avoids the confusion and memorizing of button locations seen with the manual response modality, allowing the neural correlates of FA to be investigated in AD patients.
Assessing Sleep Disturbance in Low Back Pain: The Validity of Portable Instruments
Saad M. Alsaadi, James H. McAuley, Julia M. Hush, Delwyn J. Bartlett, Zoe M. McKeough, Ronald R. Grunstein, George C. Dungan, Chris G. Maher
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0095824
Abstract: Although portable instruments have been used in the assessment of sleep disturbance for patients with low back pain (LBP), the accuracy of the instruments in detecting sleep/wake episodes for this population is unknown. This study investigated the criterion validity of two portable instruments (Armband and Actiwatch) for assessing sleep disturbance in patients with LBP. 50 patients with LBP performed simultaneous overnight sleep recordings in a university sleep laboratory. All 50 participants were assessed by Polysomnography (PSG) and the Armband and a subgroup of 33 participants wore an Actiwatch. Criterion validity was determined by calculating epoch-by-epoch agreement, sensitivity, specificity and prevalence and bias- adjusted kappa (PABAK) for sleep versus wake between each instrument and PSG. The relationship between PSG and the two instruments was assessed using intraclass correlation coefficients (ICC 2, 1). The study participants showed symptoms of sub-threshold insomnia (mean ISI = 13.2, 95% CI = 6.36) and poor sleep quality (mean PSQI = 9.20, 95% CI = 4.27). Observed agreement with PSG was 85% and 88% for the Armband and Actiwatch. Sensitivity was 0.90 for both instruments and specificity was 0.54 and 0.67 and PABAK of 0.69 and 0.77 for the Armband and Actiwatch respectively. The ICC (95%CI) was 0.76 (0.61 to 0.86) and 0.80 (0.46 to 0.92) for total sleep time, 0.52 (0.29 to 0.70) and 0.55 (0.14 to 0.77) for sleep efficiency, 0.64 (0.45 to 0.78) and 0.52 (0.23 to 0.73) for wake after sleep onset and 0.13 (?0.15 to 0.39) and 0.33 (?0.05 to 0.63) for sleep onset latency, for the Armband and Actiwatch, respectively. The findings showed that both instruments have varied criterion validity across the sleep parameters from excellent validity for measures of total sleep time, good validity for measures of sleep efficiency and wake after onset to poor validity for sleep onset latency.
Radiative Decay of Neutron-Unbound Intruder States in $^{19}$O
R. Dungan,S. L. Tabor,Vandana Tripathi,A. Volya,K. Kravvaris,B. Abromeit,D. D. Caussyn,S. Morrow,J. J. Parker IV,P. -L. Tai,J. M. VonMoss
Physics , 2015,
Abstract: The $^{9}$Be($^{14}$C, $\alpha$$\gamma$) reaction at E$_{Lab}$=30 and 35 MeV was used to study excited states of $^{19}$O. The Florida State University (FSU) $\gamma$ detector array was used to detect $\gamma$ radiation in coincidence with charged particles detected and identified with a silicon $\Delta$E-E particle telescope. Gamma decays have been observed for the first time from six states ranging from 368 to 2147 keV above the neutron separation energy (S$_{n}$=3962 keV) in $^{19}$O. The $\gamma$ decaying states are interspersed among states previously observed to decay by neutron emission. The ability of electromagnetic decay to compete successfully with neutron decay is explained in terms of neutron angular momentum barriers and small spectroscopic factors implying higher spin and complex structure for these intruder states. These results illustrate the need for complementary experimental approaches to best illuminate the complete nuclear structure.
Fostering critical thinking skills: a strategy for enhancing evidence based wellness care
Jennifer R Jamison
Chiropractic & Manual Therapies , 2005, DOI: 10.1186/1746-1340-13-19
Abstract: This paper describes a unit which prepares chiropractic students for the role of "wellness coaches". Emphasis is placed on providing students with exercises in critical thinking in an effort to prepare them for the challenge of interfacing with an increasingly evidence based health care system.This case study describes how health may be promoted and disease prevented through development of personalized wellness programs. As critical thinking is essential to the provision of evidence based wellness care, diverse learning opportunities for developing and refining critical thinking skills have been created. Three of the learning opportunities are an intrinsic component of the subject and, taken together, contributed over 50% of the final grade of the unit. They include a literature review, developing a client wellness contract and peer evaluation. In addition to these 3 compulsory exercises, students were also given an opportunity to develop their critical appraisal skills by undertaking voluntary self- and unit evaluation. Several opportunities for informal self-appraisal were offered in a structured self-study guide, while unit appraisal was undertaken by means of a questionnaire and group discussion at which the Head of School was present.Formal assessment showed all students capable of preparing a wellness program consistent with current thinking in contemporary health care. The small group of students who appraised the unit seemed to value the diversity of learning experiences provided. Opportunities for voluntary unit and self-appraisal were used to varying degrees.Unit evaluation provided useful feedback that led to substantial changes in unit structure.Students have demonstrated themselves capable of applying critical thinking in construction of evidence based wellness programs. With respect to unit design, selective use of learning opportunities highlighted the desirability of using obligatory learning opportunities to ensure exposure to core constructs while
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