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Search Results: 1 - 10 of 170158 matches for " Brittany E. Evans "
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Determinants of Physiological and Perceived Physiological Stress Reactivity in Children and Adolescents
Brittany E. Evans, Kirstin Greaves-Lord, Anja S. Euser, Joke H. M. Tulen, Ingmar H. A. Franken, Anja C. Huizink
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0061724
Abstract: Aims Abnormal physiological stress reactivity is increasingly investigated as a vulnerability marker for various physical and psychological health problems. However, studies are inconsistent in taking into account potential covariates that may influence the developing stress system. We systematically tested determinants (individual, developmental, environmental and substance use-related) of physiological and perceived physiological stress reactivity. We also examined the relation between physiological and perceived physiological stress reactivity. Method In a stratified sample of 363 children (7–12 years) and 344 adolescents (13–20 years) from the general population, we examined cortisol, heart rate, respiratory sinus arrhythmia and perceived physiological stress reactivity to a psychosocial stress procedure. Results Using multivariate linear regression models, we found that individual, developmental, environmental and substance use-related factors were related to each of the stress response indices. These determinant factors were different for each of the stress reactivity indices, and different in children versus adolescents. Perceived physiological stress reactivity predicted cortisol reactivity in adolescents only. All other relations between perceived physiological and physiological stress reactivity were not significant. Conclusions As physiological stress variables are often examined as vulnerability markers for the development of health problems, we maintain that it is essential that future studies take into consideration factors that may account for found relations. Our study provides an overview and indication of which variables should be considered in the investigation of the relation between physiological stress indices and illness.
Multifactorial Determinants of Target and Novelty-Evoked P300 Amplitudes in Children of Addicted Parents
Anja S. Euser, Brittany E. Evans, Kirstin Greaves-Lord, Ben J. M. van de Wetering, Anja C. Huizink, Ingmar H. A. Franken
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0080087
Abstract: Background Although P300 amplitude reductions constitute a persistent finding in children of addicted parents, relatively little is known about the specificity of this finding. The major aim of this study was to investigate the association between parental rearing, adverse life events, stress-reactivity, substance use and psychopathology on the one hand, and P300 amplitude in response to both target and novel distracter stimuli on the other hand. Moreover, we assessed whether risk group status (i.e., having a parental history of Substance Use Disorders [SUD]) uniquely contributed to P300 amplitude variation above and beyond these other variables. Methods Event-related potentials were recorded in high-risk adolescents with a parental history of SUD (HR;n=80) and normal-risk controls (NR;n=100) while performing a visual Novelty Oddball paradigm. Stress-evoked cortisol levels were assessed and parenting, life adversities, substance use and psychopathology were examined by using self-reports. Results HR adolescents displayed smaller P300 amplitudes in response to novel- and to target stimuli than NR controls, while the latter only approached significance. Interestingly, the effect of having a parental history of SUD on target-P300 disappeared when all other variables were taken into account. Externalizing problem behavior was a powerful predictor of target-P300. In contrast, risk group status uniquely predicted novelty-P300 amplitude reductions above and beyond all other factors. Conclusion Overall, the present findings suggest that the P300 amplitude reduction to novel stimuli might be a more specific endophenotype for SUD than the target-P300 amplitude. This pattern of results underscores the importance of conducting multifactorial assessments when examining important cognitive processes in at-risk adolescents.
Subsurface Facies Analysis of the Late Cambrian Mt. Simon Sandstone in Western Ohio (Midcontinent North America)  [PDF]
Aram Saeed, James E. Evans
Open Journal of Geology (OJG) , 2012, DOI: 10.4236/ojg.2012.22004
Abstract: The Cambrian Mt. Simon Sandstone (MSS) is a possible unconventional gas reservoir in the Illinois, Michigan, and Appalachian Basins, but comparatively little is known about the unit. This study used core and well logs from two deep exploratory wells to interpret the depositional environment of the MSS under western Ohio, where the MSS is about 120 m thick and found 1060 m below ground surface. In western Ohio, the MSS unconformably overlies the Precambrian Middle Run Formation, is conformably overlain by the Cambrian Eau Claire Formation, and has a distinctive gamma-ray log-signature. In well DGS-2627, the MSS consists of tan, friable, moderately sorted, rounded, coarse- to very coarse-grained siliceous quartz arenite with minor heterolithic sandstone-mudstone couplets (rhythmites) and quartz granule conglomerate. Features indicative of tidally-influenced, shallow marine settings include tidal rhythmites, lenticular-, flaser-, and wavy-bedding, herringbone cross-bedding, mud-drapes, tidal bundles, reactivation surfaces, intraclasts, and bioturbation. The unit generally coarsens- and thickens-upward, and is interpreted as migration of a tidally-influenced transgressive barrier sequence. A subsurface facies model for the MSS is developed by interpreting geophysical logs and cores from DGS-2627l, and this model is semi-quantitatively tested by first interpreting well BP-4 using geophysical logs alone, then confirming the results using core.
Channel Evolution of Sandy Reservoir Sediments Following Low-Head Dam Removal, Ottawa River, Northwestern Ohio, U.S.A.  [PDF]
Nathan Harris, James E. Evans
Open Journal of Modern Hydrology (OJMH) , 2014, DOI: 10.4236/ojmh.2014.42004
Dozens of low-head dams are removed annually for reasons of obsolescence, financial liability, public safety, or as part of aquatic ecosystem restoration. Prior to removing a dam, hydrologic and sedimentologic studies are used to predict channel changes that would occur after the proposed dam removal. One commonly used predictive approach is a channel evolution model (CEM). However, most CEMs assume that the reservoir has trapped cohesive silts and muds. This study looks at the effects of low-head dam removal on a reservoir in filled with sand-rich sediment. The Secor Dam (2.5 m tall, 17 m wide) was constructed on the Ottawa River in northwestern Ohio (USA) during 1928 and was removed in 2007. High resolution channel cross-sections were measured at 17 locations prior to dam removal and re-measured every approximately 30 days for 6 months following the removal. Sediment sampling, sediment traps, substrate sampling, differential GPS tracking of channel bed forms and sediment coring were also used to characterize the channel sediment response to dam removal. Breaching of the dam produced a diffuse nickzone which was the width of the channel and about 10 m in length. One initial response was downstream migration of a sediment wave at rates up to 0.5 m/hr. The overall effect was erosion of the former reservoir to a distance of 150 m upstream of the former dam. Portions of the former reservoir were incised >1 m. Within the first 6 months after removal, approximately 800 m3 of sand had been mobilized from the former reservoir, transported downstream past the former dam, and had primarily in-filled pre-existing pools within a reach approximately 150 m downstream of the former dam. This behavior significantly differs from the predicted results of current CEMs which anticipate a first flush of suspended sediment and minor deposition of bed load materials in the channel downstream of the former dam.
Shallow-Water Origin of a Devonian Black Shale, Cleveland Shale Member (Ohio Shale), Northeastern Ohio, USA  [PDF]
Saeed Alshahrani, James E. Evans
Open Journal of Geology (OJG) , 2014, DOI: 10.4236/ojg.2014.412048
Abstract: Black shales are usually interpreted to require anoxic bottom waters and deeper water sedimentation. There has long been a debate about whether the Devonian Cleveland Shale Member of the Ohio Shale (CSM) was deposited in shallow- or deep-water depositional environments. This study looked at the CSM at 3 stratigraphic sections and 5 well cores in northeastern Ohio. The CSM mostly consists of sapropelite (interbedded carbonaceous black mudstones and gray calcareous claystones). The black and gray “shales” are rhythmically bedded at micro- (<1 cm thick), meso- (<10 cm thick) and macro-scales (10s of cm thick) and represent changes in organic matter content (ranging from 7% - 20% TOC). Three types of event layers are interbedded with the mudrocks: 1) tempestites, 2) proximal turbidites, and 3) hyperpycnites. Individual tempestites and turbidites are laterally continuous ≥35 km, while hyperpycnites are too thin (<1 cm) to trace laterally. Tempestites consist of hummocky stratified sandstones with groove casts and escape burrows overlain by planar laminated sandstones with wave ripples at the top. Tempestites average 13 cm thick, but can be amalgamated up to 45 cm thick, and are more common in the lower half of the unit. Turbidites are incomplete Bouma sequences that average 6 cm thick, show evidence of combined flow (“wave-modified turbidites”), and are more common toward the top of the unit. Hyperpycnites (density underflows from river discharge) consist of inverse-to-normal graded sandy or silty microlaminae that have been studied primarily by using petrography and SEM. Condensed sections in the CSM are probable firmgrounds with carbonate concretions, and indicate intervals of low sedimentation rates. The evidence shows that the CSM depositional environment was receiving siliciclastics from the northeast (e.g., Catskill delta), and that the coarser-grained clastic sediment was primarily transported as density underflows (turbidites and hyperpycnites). However, significant storm deposits (tempestites) within the CSM indicate erosion and redeposition occurred on a muddy clastic marine shelf at paleo-water depths less than storm-weather wave base (probably ≤50 m depth).
Antioxidant and Anti-Inflammatory Effects of Peanut Skin Extracts  [PDF]
Wanida E. Lewis, Gabriel K. Harris, Timothy H. Sanders, Brittany L. White, Lisa L. Dean
Food and Nutrition Sciences (FNS) , 2013, DOI: 10.4236/fns.2013.48A003
Abstract: Peanut skins are regarded as a low economic value by-product of the peanut industry; however, they contain high levels of bioactive compounds including catechins and procyanidins, which are known for their health-promoting properties. The in vitro antioxidant activity of peanut skin extracts (PSE) has been reported but the associated anti-inflammatory properties have not been widely examined. This study investigated the anti-inflammatory effects of PSE on the pro-inflammatory enzyme, Cyclooxygenase-2 (COX-2) protein expression, on its downstream product, prostaglandin E2 (PGE2), and on nitrous oxide (NO) levels. Defatted peanut skins were extracted using two aqueous solvent mixtures (50% acetone and 90% ethanol), in order to compare the effects of the two solvent systems on antioxidant and anti-inflammatory properties. PSE antioxidant activity was determined by the hydrophilic oxygen radical absorbance capacity (H-ORAC) assay, while total phenolics were determined by the Folin-Ciocalteu assay and flavan-3-ols and procyanidins were quantified by HPLC. Acetone extracted PSE (A-PSE) exhibited numerically, but not statistically higher H-ORAC and total phenolic values than the ethanol extracted PSE (E-PSE) (1836 μmol Trolox/100 g and 67.9 mg GAE/g, and 1830 μmol Trolox/100 g and 51.8 GAE/g respectively). A-PSE also had higher levels of flavan-3-ols and procyanidins than E-PSE. RAW 264.7 cells were pretreated with 1.0%, 2.5% and 5.0% (v/v) of A-PSE or E-PSE and induced with the inflammatory marker, lipopolysaccharide (LPS) for 12 hours. COX-2 protein expression, measured by Western blotting was significantly (p < 0.05) inhibited by A-PSE and E-PSE at 2.5% and 5.0% concentrations. PGE2 and NO levels measured by ELISA, were significantly (p < 0.05) decreased with increasing added levels of A-PSE and E-PSE suggesting that A-PSE and E-PSE not also possess similar antioxidant properties, but also exhibit similar anti-inflammatory effects.
UV Spectroscopy of Star-Grazing Comets within the 49 Ceti Debris Disk
Brittany E. Miles,Aki Roberge,Barry Welsh
Physics , 2015,
Abstract: We present analysis of time-variable, shifted absorption features in far-UV spectra of the unusual 49 Ceti debris disk. This nearly edge-on disk is one of the brightest known, and is one of the very few containing detectable amounts of circumstellar gas as well as dust. In our two visits of Hubble Space Telescope STIS spectra, variable absorption features are seen on the wings of lines arising from C II and C IV, but not for any of the other circumstellar absorption lines. Similar variable features have long been seen in spectra of the well-studied $\beta$ Pictoris debris disk and attributed to the transits of star-grazing comets. We calculate the velocity ranges and apparent column densities of the 49 Cet variable gas, which appears to be moving at velocities of tens to hundreds of km s$^{-1}$ relative to the central star. The velocities of the gas in the redshifted variable event in Visit 2 show that the maximum distances of the infalling gas at the time of transit are about 0.05 to 0.2 AU from the central star. A preliminary attempt at a composition analysis of the redshifted event suggests that the C/O ratio in the infalling gas may be super-solar, as it is in the bulk of the stable disk gas.
Investigation of Open Abdomen Visceral Skin Graft Revascularization and Separation from Peritoneal Contents  [PDF]
Katharine E. Caldwell, Ross M. Clark, Brittany B. Coffman, Jacquelyn S. Brandenburg, Thomas R. Howdieshell
Surgical Science (SS) , 2018, DOI: 10.4236/ss.2018.91004
Abstract: Background: Despite increasing survival following damage control laparotomy and open abdomen technique, little is known about the biology of visceral skin graft revascularization and separation from peritoneal contents. Methods: Following laparotomy for trauma, patients with visceral edema preventing fascial closure underwent Vicryl mesh closure followed by visceral split-thickness skin grafting and readmission graft excision and abdominal wall reconstruction. Utilizing laser speckle contrast imaging, immunochemical staining of histologic sections, and RT-PCR array technology, we examined the revascularization, microvascular anatomy, morphology, and change in gene expression of visceral skin grafts. Results: Ten patients ranging in age from 25 to 46 years underwent visceral grafting for cutaneous coverage of an open abdomen. Skin graft perfusion peaked at a mean of 350 PU by post-operative day 14 synchronous with closure of meshed interstices, and remained constant until excision. Time to graft excision ranged from 6 to 18 months. CD-31 immunostaining documented a significant (p = 0.04) increase in vascular surface area in excised grafts compared to control skin. Trichrome staining revealed an 8-fold increase in excised graft thickness. Mesothelial cells were identified within the dermal matrix of excised grafts. RT-PCR demonstrated significant up-regulation of genes involved in matrix structure and remodeling, cytoskeleton regulation, and WNT signaling; and down-regulation of genes involved in inflammation and matrix proteolysis in excised grafts compared to control skin. Conclusion: Our data document early visceral skin graft perfusion and a plateau in revascularization. Histology reveals a robust dermal matrix populated by fibroblasts and mesothelial cells within a complex supporting vascular network. Genetic analysis of excised grafts reveals growth factor, collagen, and matrix remodeling gene expression.
Control of Glyphosate-Resistant Waterhemp with Two-Pass Weed Control Strategies in Glyphosate/Dicamba-Resistant Soybean  [PDF]
Brittany K. Hedges, Nader Soltani, David C. Hooker, Darren E. Robinson, Peter H. Sikkema
American Journal of Plant Sciences (AJPS) , 2018, DOI: 10.4236/ajps.2018.97104
Abstract: Waterhemp is a small-seeded, dioecious, broadleaf weed that emerges throughout the growing season. If left uncontrolled, waterhemp interference can reduce soybean yield up to 73%. Glyphosate-resistant (GR) waterhemp was first discovered in one county in Ontario in 2014; as of 2017, it has been found in two other counties. Glyphosate/dicamba-resistant soybean can be sprayed with glyphosate and/or dicamba preplant (PP), preemergence (PRE) and/or postemergence (POST). The objective of this study was to determine the control of GR waterhemp in glyphosate/dicamba-resistant soybean with PRE residual herbicides, glyphosate/dicamba applied POST or a two-pass program of a PRE residual herbicide followed by
Avulsion Dynamics in a River with Alternating Bedrock and Alluvial Reaches, Huron River, Northern Ohio (USA)  [PDF]
Mark J. Potucek, James E. Evans
Open Journal of Modern Hydrology (OJMH) , 2019, DOI: 10.4236/ojmh.2019.91002
Abstract: The Huron River consists of alternating bedrock reaches and alluvial reaches. Analysis of historical aerial photography from 1950-2015 reveals six major channel avulsion events in the 8-km study area. These avulsions occurred in the alluvial reaches but were strongly influenced by the properties of the upstream bedrock reach (“inherited characteristics”). The bedrock reaches aligned with the azimuth of joint sets in the underlying bedrock. One inherited characteristic in the alluvial reach downstream is that the avulsion channels diverged only slightly from the orientation of the upstream bedrock channel (range 2 ° - 38 °, mean and standard deviation 12.1 ° ± 13.7 °). A second inherited characteristic is that avulsion channels were initiated from short distances downstream after exiting the upstream bedrock channel reach (range 62 - 266 m, mean and standard deviation 143.7 ± 71.0 m), which is a fraction of the meander wavelength (1.2 km). Field evidence shows that some avulsion channel sites were re-occupied episodically. In addition, two properties were necessary for channel avulsions: 1) avulsion events were triggered by channel-forming hydrologic events (5-year recurrence interval flows), but not every channel-forming hydrologic event resulted in an avulsion, and 2) channel sinuosity (P) increased to 1.72 - 1.77 prior to an avulsion then decreased to 1.65 - 1.70 following an avulsion, suggesting that P ≥ 1.72 is the “critical sinuosity” or triggering value for avulsions on the Huron River. In summary, for this river consisting of alternating bedrock and alluvial reaches, the bedrock reaches impose certain parameters on downstream alluvial reaches (including sediment supply, channel direction and avulsion channel position downstream after exiting a bedrock reach) while adjustments in sinuosity and sediment storage occur in the alluvial reaches.
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