304 results on '"Donald J. Brown"'
Search Results
2. Long‐term changes in occurrence, relative abundance, and reproductive fitness of bat species in relation to arrival of White‐nose Syndrome in West Virginia, USA
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Catherine Johnson, Donald J. Brown, Chris Sanders, and Craig W. Stihler
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bats ,body condition ,Corynorhinus townsendii virginianus ,disease ,Eptesicus fuscus ,generalized additive model ,Ecology ,QH540-549.5 - Abstract
Abstract White‐nose syndrome (WNS) is a disease caused by the fungus Pseudogymnoascus destructans which has resulted in the deaths of millions of bats across eastern North America. To date, hibernacula counts have been the predominant means of tracking the spread and impact of this disease on bat populations. However, an understanding of the impacts of WNS on demographic parameters outside the winter season is critical to conservation and recovery of bat populations impacted by this disease. We used long‐term monitoring data to examine WNS‐related impacts to summer populations in West Virginia, where WNS has been documented since 2009. Using capture data from 290 mist‐net sites surveyed from 2003 to 2019 on the Monongahela National Forest, we estimated temporal patterns in presence and relative abundance for each bat species. For species that exhibited a population‐level response to WNS, we investigated post‐WNS changes in adult female reproductive state and body mass. Myotis lucifugus (little brown bat), M. septentrionalis (northern long‐eared bat), and Perimyotis subflavus (tri‐colored bat) all showed significant decreases in presence and relative abundance during and following the introduction of WNS, while Eptesicus fuscus (big brown bat) and Lasiurus borealis (eastern red bat) responded positively during the WNS invasion. Probability of being reproductively active was not significantly different for any species, though a shift to earlier reproduction was estimated for E. fuscus and M. septentrionalis. For some species, body mass appeared to be influenced by the WNS invasion, but the response differed by species and reproductive state. Results suggest that continued long‐term monitoring studies, additional research into impacts of this disease on the fitness of WNS survivors, and a focus on providing optimal nonwintering habitat may be valuable strategies for assessing and promoting recovery of WNS‐affected bat populations.
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- 2021
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3. Influence of landscape condition on relative abundance and body condition of two generalist freshwater turtle species
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Joel L. Mota, Donald J. Brown, Danielle M. Canning, Sara M. Crayton, Darien N. Lozon, Alissa L. Gulette, James T. Anderson, Ivana Mali, Brian E. Dickerson, Michael R. J. Forstner, Mark B. Watson, and Thomas K. Pauley
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Chrysemys picta ,habitat generalist ,land use ,Trachemys scripta elegans ,Ecology ,QH540-549.5 - Abstract
Abstract Anthropogenic land use changes have broad impacts on biological diversity, often resulting in shifts in community composition. While many studies have documented negative impacts on occurrence and abundance of species, less attention has been given to native species that potentially benefit from anthropogenic land use changes. For many species reaching high densities in human‐dominated landscapes, it is unclear whether these environments represent higher quality habitat than more natural environments. We examined the influence of landscape ecological integrity on relative abundance and body condition of two native generalist freshwater turtle species that are prevalent in anthropogenic systems, the painted turtle (Chrysemys picta) and red‐eared slider (Trachemys scripta elegans). Relative abundance was negatively associated with ecological integrity for both species, but the relationship was not strongly supported for painted turtles. Body condition was positively associated with ecological integrity for painted turtles, with no strong association for red‐eared sliders. Our study suggests that both species benefitted at the population level from reduced ecological integrity, but individual‐level habitat quality was reduced for painted turtles. The differing responses between these two habitat generalists could partially explain why red‐eared sliders have become a widespread exotic invasive species, while painted turtles have not.
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- 2021
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4. Distinct forest bird communities are strongly associated with red spruce-northern hardwood ecosystems in Central Appalachia, USA
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Hannah L. Clipp, Donald J. Brown, Christopher T. Rota, and Petra B. Wood
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Appalachian Mountains ,Avian diversity ,Ecological indicator ,Indicator species analysis ,Multivariate regression trees ,Restoration ,Ecology ,QH540-549.5 - Abstract
Degraded red spruce (Picea rubens)-northern hardwood ecosystems are the focus of restoration efforts across high-elevation landscapes in the Central Appalachian region of the eastern United States. To promote ecosystem function and long-term sustainability of restored forests, it is important to understand the associated biota, including bird communities. Certain bird species could serve as ecological indicators, with potential applications for evaluating restoration efforts. However, contemporary and statistically rigorous studies of red spruce bird communities in this region are lacking, as is a formal analysis of indicator species. The purpose of this study was to use multivariate regression trees and indicator species analyses to determine if bird communities and individual bird species, respectively, are strongly associated with the red spruce-northern hardwood ecosystem in Central Appalachia. Specifically, we assessed those associations with three distinct but complementary sets of forest characteristics, focusing on (1) red spruce and northern hardwood forest types, (2) classes of percent red spruce cover, and (3) red spruce and northern hardwood stand size classes. Community-wide avian point count survey data were collected in mid-May to mid-July 2010–2019 at 645 sampling points located in forest stands throughout the Monongahela National Forest in West Virginia. We found that red spruce and northern hardwood forest types had distinct bird communities within the study area, and that community composition differed among red spruce cover classes. In addition, forest type was more influential on bird community composition than stand size class (poletimber or sawtimber). Eleven indicator species were consistently associated with red spruce forests, whereas fewer species were identified as indicator species for northern hardwood forests. Ultimately, the distinctiveness of the bird community in red spruce forests and strength of those associations highlight the critical need for and importance of restoration efforts targeting red spruce-northern hardwood ecosystems in the Central Appalachians to ensure long-term maintenance of regional avian diversity.
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- 2022
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5. Influence of climate change and postdelisting management on long‐term population viability of the conservation‐reliant Kirtland's Warbler
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Donald J. Brown, Deahn M. Donner, Christine A. Ribic, and Carol I. Bocetti
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Bahamas ,bird ,jack pine ,Michigan ,migratory ,Setophaga kirtlandii ,Ecology ,QH540-549.5 - Abstract
Abstract Rapid global climate change is resulting in novel abiotic and biotic conditions and interactions. Identifying management strategies that maximize probability of long‐term persistence requires an understanding of the vulnerability of species to environmental changes. We sought to quantify the vulnerability of Kirtland's Warbler (Setophaga kirtlandii), a rare Neotropical migratory songbird that breeds almost exclusively in the Lower Peninsula of Michigan and winters in the Bahamian Archipelago, to projected environmental changes on the breeding and wintering grounds. We developed a population‐level simulation model that incorporates the influence of annual environmental conditions on the breeding and wintering grounds, and parameterized the model using empirical relationships. We simulated independent and additive effects of reduced breeding grounds habitat quantity and quality, and wintering grounds habitat quality, on population viability. Our results indicated the Kirtland's Warbler population is stable under current environmental and management conditions. Reduced breeding grounds habitat quantity resulted in reductions of the stable population size, but did not cause extinction under the scenarios we examined. In contrast, projected large reductions in wintering grounds precipitation caused the population to decline, with risk of extinction magnified when breeding habitat quantity or quality also decreased. Our study indicates that probability of long‐term persistence for Kirtland's Warbler will depend on climate change impacts to wintering grounds habitat quality and contributes to the growing literature documenting the importance of considering the full annual cycle for understanding population dynamics of migratory species.
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- 2019
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6. Bioaccumulation of the pesticide imidacloprid in stream organisms and sublethal effects on salamanders
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Sara M. Crayton, Petra B. Wood, Donald J. Brown, Alice R. Millikin, Terence J. McManus, Tyler J. Simpson, Kang-Mo Ku, and Yong-Lak Park
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Imidacloprid ,Bioaccumulation ,Stream salamanders ,Hemlock woolly adelgid ,Corticosterone ,Body condition index ,Ecology ,QH540-549.5 - Abstract
Neonicotinoids are one of the most widely used classes of insecticides in the world. The neonicotinoid imidacloprid is commonly applied to hemlock (Tsuga spp.) stands in eastern North America to reduce tree mortality from infestations of the invasive hemlock woolly adelgid (HWA; Adelges tsugae). While laboratory and mesocosm studies have determined that imidacloprid can bioaccumulate in anurans and cause sublethal effects, no field studies have investigated whether salamanders or insects in streams adjacent to HWA treatments bioaccumulate imidacloprid or if sublethal effects are detectable in wild salamanders. We assessed relationships between imidacloprid exposure and stream salamander health in West Virginia, USA, using concentration of the stress hormone corticosterone and body condition indices (BCI) as response variables. Of 107 Desmognathus salamanders from 11 sites tested for bioaccumulation, we detected imidacloprid in 47 salamanders. Of 15 benthic macroinvertebrate samples tested, we detected imidacloprid, imidacloprid-urea, and imidacloprid-olefin in 15, 13, and 1 sample, respectively. Based on 115 Desmognathus salamanders sampled at 11 sites for stress hormone responses, corticosterone concentration increased with imidacloprid concentration in stream water. For 802 salamanders sampled at 48 sites, BCI decreased as concentration of imidacloprid in stream water increased, but explanatory power was low. Our study suggests that chronic leaching of imidacloprid from treated hemlock stands into adjacent streams has the potential to negatively affect aquatic organisms and may provide a route of exposure to higher trophic levels.
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- 2020
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7. Morphometric data for five freshwater turtles in south, central, and west Texas
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Donald J. Brown, Ivana Mali, Melissa C. Jones, and Michael R.J. Forstner
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Computer applications to medicine. Medical informatics ,R858-859.7 ,Science (General) ,Q1-390 - Abstract
From 2008 to 2013, we sampled freshwater turtle populations at 66 sites in south, central, and west Texas, USA. Sampling sites included ponds, lakes, resacas (oxbow lakes), canals, and rivers. We sampled turtle populations using baited hoop nets (66 sites) and basking traps (3 sites), and captured turtles by hand opportunistically in terrestrial habitat. We measured carapace length and width, plastron length and width, body depth, and weight of captured turtles. Excluding recaptures, we measured 356 Apalone spinifera emoryi (Texas Spiny Softshell), 24 Chelydra serpentina (Snapping Turtle), 20 Kinosternon flavescens (Yellow Mud Turtle), 47 Trachemys gaigeae (Big Bend Slider), and 1070 Trachemys scripta elegans (Red-eared Slider). Carapace length of Apalone spinifera emoryi ranged from 85 to 426 mm (mean = 182 mm). Carapace length of Chelydra serpentina ranged from 74 to 320 mm (mean = 233 mm). Carapace length of Kinosternon flavescens ranged from 64 to 147 mm (mean = 114 mm). Carapace length of Trachemys gaigeae ranged from 54 to 203 mm (mean = 141 mm). Carapace length of Trachemys scripta elegans ranged from 30 to 328 mm (mean = 171 mm). These data are useful for assessing spatial and temporal variation in size and body condition of freshwater turtles. Keywords: Carapace, Plastron, Weight, Apalone spinifera emoryi, Chelydra serpentina, Kinosternon flavescens, Trachemys gaigeae, Trachemys scripta elegans
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- 2020
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8. Vulnerability of high-elevation endemic salamanders to climate change: A case study with the Cow Knob Salamander (Plethodon punctatus)
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Carl D. Jacobsen, Donald J. Brown, William D. Flint, Thomas K. Pauley, Kurt A. Buhlmann, and Joseph C. Mitchell
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Ecology ,QH540-549.5 - Abstract
Rapid contemporary climate change is a potential threat to long-term persistence of montane wildlife species because they often have narrow thermal tolerances and have limited potential to shift their distributions. The Appalachian Mountain region in the eastern United States is a global biodiversity hotspot for woodland salamanders (genus Plethodon), many of which are high-elevation endemic species. Robust assessments of the vulnerability of high-elevation endemic salamanders to climate change, including delineation of future potential climate refugia, are needed to guide climate change adaptations strategies. The Cow Knob Salamander (Plethodon punctatus) is a species of conservation concern found at high elevations in the Valley and Ridge Province of western Virginia and eastern West Virginia. We used habitat suitability models to examine relationships between landscape characteristics, climate variables, and P. punctatus occurrence, and estimated effects of future climate scenarios on the species’ climatic niche. We found that elevation, slope, aspect, and hillshade were influential landscape predictors of species occurrence, and that mean annual temperature was the most influential climate variable. Future climate projections indicated this species will likely lose most of its climatic niche by mid-century, and that amount of suitable habitat will continue to decline through 2100. We identified several pockets of habitat that may represent climate change refugia for P. punctatus due to cooler microclimates from greater hillshade and aspects that receive less direct solar radiation; however, we found these refugia exist in small, isolated habitat patches. Our study provides quantitative estimates that support the general concern that high-elevation endemic salamanders are particularly vulnerable to climate change. Our models can be used by natural resource managers to guide current P. punctatus monitoring and habitat conservation efforts, as well as to identify focal areas that will likely serve as refugia for the species as the climate continues to change over this century. Keywords: Amphibian, Appalachia, Climate change, George Washington National Forest, Habitat suitability model, MaxLike
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- 2020
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9. Trade-offs relating to grassland and forest mine reclamation approaches in the central Appalachian region and implications for the songbird community
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Eric L. Margenau, Petra B. Wood, Cathy A. Weakland, and Donald J. Brown
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central appalachians ,mine reclamation ,songbird community ,surface mining ,Ecology ,QH540-549.5 - Abstract
Surface mining in the Appalachian region (USA) converts large areas of mature forest to early successional habitat. This shift in landscape structure has the potential to reduce habitat availability and suitability for forest-dwelling songbirds by reducing and fragmenting mature forest, but also to increase habitat availability for grassland- and shrubland-associated songbirds. We examined the influence of mountaintop mining/valley fill (MTMVF) reclamation habitats (grassland, shrubland, and remnant forest) on songbird community composition and abundance at three former MTMVF mines in southwestern West Virginia, relative to intact forest. We quantified the songbird community in 1999 and 2000 using point counts arranged throughout the mine complexes to assess landscape composition of the songbird community. Community analysis showed songbirds had strong associations with their respective guild based on species habitat preferences. Although remnant and intact forest treatments had similar species compositions, the forest interior guild had greater richness in intact rather than remnant forest. Total species richness was greatest in the reclaimed shrubland treatment. Focal species analysis followed similar trends as community assessments, because most species abundances within treatment types were strongly associated with species habitat preferences. Our results indicate that reclamation habitat decisions, i.e., grasslands versus forests, can have large effects on avian community composition. Determining appropriate mine restoration actions depends on the suite of species desired for long-term occupancy and their conservation priority.
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- 2019
10. GPS Technology for Semi-Aquatic Turtle Research
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Madaline M. Cochrane, Donald J. Brown, and Ron A. Moen
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fix success rate ,GPS technology ,location error ,Minnesota ,reptile ,stationary tests ,temperature ,wood turtle (Glyptemys insculpta) ,Biology (General) ,QH301-705.5 - Abstract
Global positioning system (GPS) telemetry units are now small enough to be deployed on terrestrial and semi-aquatic turtles. Many of these GPS units use snapshot technology which collects raw satellite and timestamp data during brief periods of data recording to minimize size. We evaluated locations from snapshot GPS units in stationary tests and on wood turtles (Glyptemys insculpta) in northeastern Minnesota. Stationary GPS units were placed in wood turtle habitat to evaluate location accuracy, fix success rate, and directional bias. The GPS fix success rate and accuracy were reduced in closed canopy conditions and when the stationary GPS unit was placed under a log to simulate wood turtle hiding behavior. We removed GPS location outliers and used a moving average calculation to reduce mean location error in stationary tests from 27 m (SD = 38) to 10 m (SD = 8). We then deployed GPS units and temperature loggers on wood turtles and collected 122,657 GPS locations and 242,781 temperature readings from 26 turtles from May to September 2015 and 2016. Location outliers accounted for 12% of locations when the GPS receiver was on a turtle. We classified each wood turtle location based on the GPS location and by comparing temperature profiles from river, sun, and shaded locations to the temperature logger on the turtle. We estimated that wood turtles were on land 68% (SD = 12) of the time from May to September. The fix success rate for land locations was 38% (SD = 9), indicating that wood turtles often use habitats with obstructed views of the sky. Mean net daily movement was 55 m (SD = 192). Our results demonstrate that snapshot GPS units and temperature loggers provide fine-scale GPS data useful in describing spatial ecology and habitat use of semi-aquatic turtles.
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- 2019
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11. A Place to Call Home: Amphibian Use of Created and Restored Wetlands
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Donald J. Brown, Garrett M. Street, Robert W. Nairn, and Michael R. J. Forstner
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Ecology ,QH540-549.5 ,General. Including nature conservation, geographical distribution ,QH1-199.5 - Abstract
Loss and degradation of wetland habitats are major contributing factors to the global decline of amphibians. Creation and restoration of wetlands could be a valuable tool for increasing local amphibian species richness and abundance. We synthesized the peer-reviewed literature addressing amphibian use of created and restored wetlands, focusing on aquatic habitat, upland habitat, and wetland connectivity and configuration. Amphibian species richness or abundance at created and restored wetlands was either similar to or greater than reference wetlands in 89% of studies. Use of created and restored wetlands by individual species was driven by aquatic and terrestrial habitat preferences, as well as ability to disperse from source wetlands. We conclude that creating and restoring wetlands can be valuable tools for amphibian conservation. However, the ecological needs and preferences of target species must be considered to maximize the potential for successful colonization and long-term persistence.
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- 2012
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12. Is the future female for turtles? Climate change and wetland configuration predict sex ratios of a freshwater species
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H. Patrick Roberts, Lisabeth L. Willey, Michael T. Jones, Thomas S. B. Akre, David I. King, John Kleopfer, Donald J. Brown, Scott W. Buchanan, Houston C. Chandler, Phillip deMaynadier, Melissa Winters, Lori Erb, Katharine D. Gipe, Glenn Johnson, Kathryn Lauer, Eric B. Liebgold, Jonathan D. Mays, Jessica R. Meck, Joshua Megyesy, Joel L. Mota, Nathan H. Nazdrowicz, Kevin J. Oxenrider, Molly Parren, Tami S. Ransom, Lindsay Rohrbaugh, Scott Smith, Derek Yorks, and Brian Zarate
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Global and Planetary Change ,Ecology ,Environmental Chemistry ,General Environmental Science - Published
- 2023
13. Amyloid Precursor Protein in Abusive Head Trauma Suspects
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Don S, Minckler, Donald J, Brown, Angele, Nalbandian, and Donny W, Suh
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Retinal Ganglion Cells ,Amyloid beta-Protein Precursor ,Ophthalmology ,Case-Control Studies ,Craniocerebral Trauma ,Humans ,Infant ,Child Abuse ,Child ,Retrospective Studies - Abstract
To study orthograde axonal transport with amyloid precursor protein (APP-A4) immunohistochemistry (IHC) in the retina and lamina cribrosa (LC) portion of the optic nerve in abusive head trauma (AHT) suspects.Retrospective, case-control study.Seventy-two eyes from suspected AHT victims referred by the Los Angeles Coroner and control eyes from nontraumatized infants were included. IHC was conducted using University of California, Irvine (UCI), Lab Medicine Department's standard protocol and results analyzed by light microcopy after paraffin processing. Quantitation of LC APP-A4 block was estimated in 21 cases with known survival using MetaMorph, a proprietary biomicroscopy imaging software.The presence or absence of APP-A4 label accumulations in retinal ganglion cells, nerve fiber layer at the disc margin, and in LC axonal bundles were compared to matching tissues from nontraumatized control eyes with only background staining. Among the globes from AHT suspects with nerve heads available for study, 94% were positive for LC accumulation of marker. Among suspect AHT cases with known survival after injury of 1 to 1588 days, most demonstrated LC APP-A4 accumulations.Our findings reinforce a recent publication based on APP-A4 IHC that demonstrated similar orthograde axonal transport block in the LC in children with AHT and recommend that intraocular pressures be recorded and addressed in these patients.
- Published
- 2022
14. Immuno Tomography (IT) and Imaging Mass Cytometry (IMC) for constructing spatially resolved, multiplexed 3D IMC data sets
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Ladan, Gheiratmand, Donald J, Brown, Daaf, Sandkuijl, Alexander, Loboda, and James V, Jester
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Mice ,Ophthalmology ,Imaging, Three-Dimensional ,Stem Cells ,Animals ,Meibomian Glands ,Plastics ,Image Cytometry - Abstract
We have previously used Immuno Tomography (IT) to identify label-retaining stem cell populations in the cornea and meibomian gland. While this method provides the unique ability to quantify stem cell populations comprised of 1-4 cells, the number of antigens that can be sequentially used to characterize these unique cells is limited by antigen stability after antibody stripping and re-probing. To address this deficiency, we have evaluated the capability of Imaging Mass Cytometry™ (IMC™) to generate multiplexed images using metal-conjugated antibodies to label IT plastic sections and generate 3-dimensional IMC data sets (3D IMC).K5-H2B-GFP mice, 56 days after doxycycline chase, were sacrificed and eyelid tissue processed for IT. A total of 400 serial, plastic sections, 2 μm thick, were then probed using metal-tagged antibodies specific for sox 9, collagen type I, E-cadherin, Ki67, GFP, αSMA, vimentin, and DNA intercalator. Multiplexed images were then generated using an Imaging Mass Cytometry system (Fluidigm®), and 3D reconstructions were assembled.All 8 metal-labeled tags were detected and their images were successfully assembled into 3D IMC data sets. GFP-labeled nuclei were identified within the meibomian glands in comparable numbers to those previously reported for slow-cycling meibomian gland stem cells.These findings demonstrate that IMC can be used on plastic sections to generate multiplexed, 3D data sets that can be reconstructed to show the spatial localization of meibomian gland stem cells. We propose that 3D IMC might prove valuable in more fully characterizing stem cell populations in different tissues.
- Published
- 2022
15. Microhabitat Associations for the Threatened Cheat Mountain Salamander in Relation to Early-Stage Red Spruce Restoration Areas
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Donald J. Brown, Lacy E. Rucker, Catherine Johnson, Shane Jones, and Thomas K. Pauley
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Ecology ,Animal Science and Zoology ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
The Central Appalachian Spruce Restoration Initiative was formed to promote restoration of red spruce Picea rubens forests in Central Appalachia. One goal of the initiative is to increase availability and enhance quality of habitat for wildlife, including the threatened Cheat Mountain salamander Plethodon nettingi. The purpose of this research was to compare microhabitat characteristics between an occupied Cheat Mountain salamander site and early-stage spruce restoration sites, and between four occupied sites and proximal nondetection sites. We found that soil pH was higher and soil moisture was lower at spruce restoration sites compared with the occupied site, and that light intensity, subcanopy air temperature, and ground-level air temperature were higher in spruce restoration sites with reduced canopy cover. We found that soil moisture was higher at occupied sites compared with proximal nondetection sites, but soil pH was not significantly different. Our study suggests that Cheat Mountain salamanders are associated with low soil pH and high soil moisture, and thus spruce restoration could enhance habitat quality for this species in the long-term.
- Published
- 2022
16. Expression of Acyl-CoA wax-alcohol acyltransferase 2 (AWAT2) by human and rabbit meibomian glands and meibocytes
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Fangyuna Gao, James V. Jester, Donald J. Brown, Yilu Xie, Chang Rae Rho, Sun Woong Kim, Jinseor Kim, Dorota Skowronska-Krawczyk, and Shelley Lane
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chemistry.chemical_classification ,Confluency ,Meibomian Glands ,RNA ,Meibomian gland ,Molecular biology ,Blot ,Ophthalmology ,Enzyme ,medicine.anatomical_structure ,chemistry ,Cell culture ,Acyltransferase ,medicine ,Animals ,Humans ,Rabbits ,Progenitor cell ,Acyltransferases - Abstract
Purpose Previously, we showed that Acyl-CoA wax-alcohol acyltransferase 2 (AWAT2), an essential enzyme required for meibum wax ester synthesis, was not expressed by immortalized human meibomian gland epithelial cells (hMGEC) in culture. To begin to understand the mechanisms controlling AWAT2 expression, we have analyzed its expression in human and rabbit meibomian glands and cultured meibocytes. Methods Rabbit meibocyte progenitor cells (rMPC) were first grown in Cnt-BM.1 basal medium (Cellntec) supplemented with rhEGF, FGF10, and ROCK inhibitor (Y-27632 dihydrochloride), and then passed at 70–80% confluency with Accutase. Differentiation of rMPC to meibocytes (rMC) was induced by removal of Y-27632 and addition of 1 mM calcium with and without PPARγ agonists. RNA from the tissue, primary, passaged rMPC and differentiated rMC were obtained for AWAT2 qPCR analysis. Proteins and cells were evaluated for western blotting and neutral lipid synthesis, respectively. For comparison, human meibomian glands were separated for RNA and protein analysis. hMGEC was cultured to collect RNA and protein. Results Rabbit rMPCs were successfully grown, passaged, and differentiated, showing a significant increase in lipid droplet accumulation. AWAT2 RNA was highly expressed in tissue but showed a −16.9 log2 fold decrease in primary and passaged rMPCs and was not induced by differentiation to rMC. By comparison, human meibomian glands showed high expression of AWAT2, and hMGEC expressed non-detectable levels of AWAT2 transcripts or protein. Conclusions AWAT2 expression is lost in cultured rMPC and rMC suggesting that cells in culture do not undergo complete meibocyte differentiation and require yet to be identified culture conditions.
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- 2022
17. A Guide to Sexing Salamanders in Central Appalachia, United States
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Donald J. Brown, Kevin R. Messenger, Thomas K. Pauley, Erik R. Wild, Lacy E. Rucker, and Carl D. Jacobsen
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Pseudotriton ,Salamandridae ,Ecology ,biology ,Wildlife ,Proteidae ,Sexing ,biology.organism_classification ,Sexual dimorphism ,Geography ,Desmognathus ,Evolutionary biology ,biology.animal ,Salamander ,Animal Science and Zoology ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
Documenting the sex of individuals encountered during wildlife research and monitoring activities is important for understanding and tracking changes in populations. However, sexing salamanders can be particularly difficult because secondary sex characters are often subtle or only visible during the breeding season, and guidance on species-specific sex determination is lacking from most field guides. The purpose of this guide is to provide a reference to assist biologists in the Central Appalachian region with identifying sex of live adult salamanders. In the main text we provide summary tables and figures to serve as concise references in the field. We provide individual species accounts that contain concise yet comprehensive information for each species based on the published literature, as well as many images depicting sexually dimorphic characters. Our focal region encompasses partial or entire distributions for 56 species of salamanders in 5 families (Ambystomidae, Cryptobranchidae, Plethodontidae, Proteidae, and Salamandridae). We identified seven morphological characters that are strongly sexually dimorphic and useful for sexing live, nonanesthetized, adult salamanders in the field, with males of individual species exhibiting one to five of the characters. We identified more than 20 additional characters that are weakly sexually dimorphic, difficult to distinguish in the field, or species-specific. Our guide serves as a synthesis of sexually dimorphic characters for salamanders in Central Appalachia, and we anticipate it will have broad value for researchers, monitoring programs, and salamander enthusiasts in eastern and central North America.
- Published
- 2021
18. Effects of landscape structure and land use on turtle communities across the eastern United States
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H. Patrick Roberts, Lisabeth L. Willey, Michael T. Jones, David I. King, Thomas S.B. Akre, John Kleopfer, Donald J. Brown, Scott W. Buchanan, Houston C. Chandler, Phillip deMaynadier, Melissa Winters, Lori Erb, Katharine D. Gipe, Glenn Johnson, Kathryn Lauer, Eric B. Liebgold, Jonathan D. Mays, Jessica R. Meck, Joshua Megyesy, Joel L. Mota, Nathan H. Nazdrowicz, Kevin J. Oxenrider, Molly Parren, Tami S. Ransom, Lindsay Rohrbaugh, Scott Smith, Derek Yorks, and Brian Zarate
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Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Published
- 2023
19. Influence of landscape condition on relative abundance and body condition of two generalist freshwater turtle species
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Alissa L. Gulette, Brian E. Dickerson, James T. Anderson, Sara M. Crayton, Donald J. Brown, Joel L. Mota, Darien N. Lozon, Thomas K. Pauley, Mark B. Watson, Michael R. J. Forstner, Ivana Mali, and Danielle M. Canning
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0106 biological sciences ,Biodiversity ,Introduced species ,Generalist and specialist species ,010603 evolutionary biology ,01 natural sciences ,law.invention ,03 medical and health sciences ,law ,Abundance (ecology) ,Turtle (robot) ,Relative species abundance ,QH540-549.5 ,Ecology, Evolution, Behavior and Systematics ,Original Research ,Trachemys scripta elegans ,030304 developmental biology ,Nature and Landscape Conservation ,0303 health sciences ,Ecology ,biology ,habitat generalist ,Chrysemys picta ,land use ,biology.organism_classification ,Habitat ,Painted turtle - Abstract
Anthropogenic land use changes have broad impacts on biological diversity, often resulting in shifts in community composition. While many studies have documented negative impacts on occurrence and abundance of species, less attention has been given to native species that potentially benefit from anthropogenic land use changes. For many species reaching high densities in human‐dominated landscapes, it is unclear whether these environments represent higher quality habitat than more natural environments. We examined the influence of landscape ecological integrity on relative abundance and body condition of two native generalist freshwater turtle species that are prevalent in anthropogenic systems, the painted turtle (Chrysemys picta) and red‐eared slider (Trachemys scripta elegans). Relative abundance was negatively associated with ecological integrity for both species, but the relationship was not strongly supported for painted turtles. Body condition was positively associated with ecological integrity for painted turtles, with no strong association for red‐eared sliders. Our study suggests that both species benefitted at the population level from reduced ecological integrity, but individual‐level habitat quality was reduced for painted turtles. The differing responses between these two habitat generalists could partially explain why red‐eared sliders have become a widespread exotic invasive species, while painted turtles have not., Identifying the differences in the relationship between landscape integrity and body condition for painted turtles and red‐eared sliders may porovide insight on how red‐eared sliders have become a widespread invasive species, while painted turtles have not. We collected and collated turtle capture and morphometric data to create model‐estimated relationships between mean 2.5 km landscape condition value (LCV) and standardized body condition index (BCI) scores for (A) painted turtles (Chrysemys picta; n = 625) sampled at 46 wetlands across 10 counties in West Virginia and (B) red‐eared sliders (Trachemys scripta elegans; n = 715) sampled at 42 wetlands across five counties in Texas.
- Published
- 2021
20. PREVALENCE OF RANAVIRUS IN SPOTTED SALAMANDER (AMBYSTOMA MACULATUM) LARVAE FROM CREATED VERNAL POOLS IN WEST VIRGINIA, USA
- Author
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Alice R. Millikin, Drew R. Davis, Donald J. Brown, Sarah K. Woodley, Stephanie Coster, Amy Welsh, Jacob L. Kerby, and James T. Anderson
- Subjects
Ecology ,Ecology, Evolution, Behavior and Systematics - Abstract
Ranavirosis is a disease of high concern for amphibians due to widespread documentation of its lethal and sublethal impacts and its high transmission potential across populations and species. We investigated whether spotted salamander (Ambystoma maculatum) ranavirus prevalence and viral load were associated with habitat characteristics, genetic diversity, corticosterone levels, and body size. In 2015 and 2016, we sampled 34 recently created vernal pools in the Monongahela National Forest, West Virginia, USA. We collected tail clippings from 1,128 spotted salamander larvae and waterborne hormone samples from 436 of those larvae, along with eight environmental characteristics of the pools. Over the 2-yr period, we detected ranavirus in 62% of pools, with prevalence ranging from 0% to 63% (mean, 7.68%). Spotted salamander size was positively correlated with ranavirus presence and viral load; however, we did not find associations between ranavirus prevalence or viral load and habitat characteristics, spotted salamander genetic diversity, relatedness, effective number of breeders, or corticosterone levels. The widespread occurrence of ranavirus in the vernal pools illustrates the potential for rapid natural introduction of the pathogen to created wetlands. Managers could consider monitoring local distributions of ranavirus before creation of new vernal pools to guide strategic placement of the wetlands to minimize occurrence and prevalence of this pathogen.
- Published
- 2022
21. Spatially structured brown-headed cowbird control measures and their effects on Kirtland’s warbler long-term population sustainability
- Author
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Eric L. Margenau, Nathan W. Cooper, Donald J. Brown, Deahn M. Donner, Peter P. Marra, and Pat Ryan
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Management, Monitoring, Policy and Law ,Ecology, Evolution, Behavior and Systematics - Published
- 2022
22. Evaluating Mechanisms of Short-term Woodland Salamander Response to Forest Management
- Author
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Eric L. Margenau, Petra B. Wood, Donald J. Brown, and Christopher W. Ryan
- Subjects
Global and Planetary Change ,Ecology ,Pollution - Abstract
Contemporary forest management often requires meeting diverse ecological objectives including maintaining ecosystem function and promoting biodiversity through timber harvesting. Wildlife are essential in this process by providing ecological services that can facilitate forest resiliency in response to timber harvesting. However, the mechanisms driving species' responses remain ambiguous. The goal of this study was to assess mechanisms influencing eastern red-backed salamander (RBS; Plethodon cinereus) response to overstory cover removal. We evaluated two mitigation strategies for the RBS in response to overstory removal. We used a before-after-control-impact design to study how (1) retaining residual trees or (2) eliminating soil compaction affected RBS surface counts and body condition index (BCI) up to two-years post-treatment. Additionally, we assessed how surface counts of RBS were influenced by overstory tree cover. Surface counts of RBS were not strongly influenced by overstory removal when tree residuals were retained. Body condition index increased in treatments where harvest residuals were retained. In treatments where soil compaction was eliminated, surface counts and BCI were inversely related. Finally, surface counts from both mitigation strategies were not strongly influenced by overstory cover. Overall, both mitigation techniques appeared to ameliorate impacts of overstory removal on RBS. These results highlight the importance of understanding mechanisms driving species' responses to forest management. To reduce the perceived negative effects of overstory removal on RBS, incorporating these mitigation measures may contribute to the viability and stability of RBS populations. Incorporating species' life history traits into management strategies could increase continuity of ecological function and integrity through harvesting.
- Published
- 2021
23. Transcriptome analysis after PPARγ activation in human meibomian gland epithelial cells (hMGEC)
- Author
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James V. Jester, Donald J. Brown, and Sun Woong Kim
- Subjects
0301 basic medicine ,Cells ,1.1 Normal biological development and functioning ,Blotting, Western ,Peroxisome proliferator-activated receptor ,Cell Count ,RNA-Seq ,Biology ,Ophthalmology & Optometry ,PPAR ,Article ,Rosiglitazone ,Transcriptome ,03 medical and health sciences ,0302 clinical medicine ,Underpinning research ,Opthalmology and Optometry ,Gene expression ,Genetics ,medicine ,Humans ,Gene ,Cells, Cultured ,chemistry.chemical_classification ,Cultured ,Blotting ,Gene Expression Profiling ,Human Genome ,Wnt signaling pathway ,Meibomian Glands ,Epithelial Cells ,Cell Differentiation ,Molecular biology ,Meibocyte ,PPAR gamma ,Human meibomian gland epithelial cell ,Ophthalmology ,030104 developmental biology ,Real-time polymerase chain reaction ,chemistry ,030221 ophthalmology & optometry ,RNA ,Western ,medicine.drug - Abstract
Purpose PPARγ plays a critical role in the maturation of immortalized human meibomian gland epithelial cells (hMGEC). To further understand the molecular changes associated with meibocyte differentiation, we analyzed transcriptome profiles from hMGEC after PPARγ activation. Methods Three sets of cultivated hMGEC with or without exposure to PPARγ agonist, rosiglitazone were used for RNA-seq analysis. RNA was isolated and processed to generate 6 libraries. The libraries were then sequenced and mapped to the human reference genome, and the expression results were gathered as reads per length of transcript in kilobases per million mapped reads (RPKM) values. Differential gene expression analyses were performed using DESeq2 and NOISeq. Gene ontology enrichment analysis (GOEA) was performed on gene sets that were upregulated or downregulated after rosiglitazone treatment. Five genes were selected for validation and differential expression was confirmed using quantitative PCR. The Differential expression of CK5 was evaluated using Western blotting. Results Expression data indicated that about 58,000 genes are expressed in hMGEC. DESeq2 and NOISeq indicated that 296 and 3436 genes were upregulated and 258 and 3592 genes were down regulated after rosiglitazone treatment, respectively. Of genes showing significant differences > 2 fold, GOEA indicated that cellular and metabolic processes were highly represented. Expression of ANGPTL4, PLIN2, SQSTM1, and DDIT3 were significantly upregulated and HHIP was downregulated by rosiglitazone. CK5 was downregulated by rosiglitazone. Conclusions The RNA-seq data suggested that PPARγ activation induced alterations in cell differentiation and metabolic process and affected multiple signaling pathways such as PPAR, autophagy, WNT, and Hedgehog.
- Published
- 2019
24. Influence of climate change and postdelisting management on long‐term population viability of the conservation‐reliant Kirtland's Warbler
- Author
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Christine A. Ribic, Deahn M. Donner, Donald J. Brown, and Carol I. Bocetti
- Subjects
0106 biological sciences ,Michigan ,bird ,Setophaga kirtlandii ,Bahamas ,Population ,Climate change ,010603 evolutionary biology ,01 natural sciences ,Warbler ,03 medical and health sciences ,lcsh:QH540-549.5 ,jack pine ,education ,Ecology, Evolution, Behavior and Systematics ,030304 developmental biology ,Nature and Landscape Conservation ,Original Research ,Abiotic component ,0303 health sciences ,education.field_of_study ,Extinction ,Ecology ,simulation model ,Population size ,Global warming ,Geography ,Habitat ,lcsh:Ecology ,migratory ,STELLA - Abstract
Rapid global climate change is resulting in novel abiotic and biotic conditions and interactions. Identifying management strategies that maximize probability of long‐term persistence requires an understanding of the vulnerability of species to environmental changes. We sought to quantify the vulnerability of Kirtland's Warbler (Setophaga kirtlandii), a rare Neotropical migratory songbird that breeds almost exclusively in the Lower Peninsula of Michigan and winters in the Bahamian Archipelago, to projected environmental changes on the breeding and wintering grounds. We developed a population‐level simulation model that incorporates the influence of annual environmental conditions on the breeding and wintering grounds, and parameterized the model using empirical relationships. We simulated independent and additive effects of reduced breeding grounds habitat quantity and quality, and wintering grounds habitat quality, on population viability. Our results indicated the Kirtland's Warbler population is stable under current environmental and management conditions. Reduced breeding grounds habitat quantity resulted in reductions of the stable population size, but did not cause extinction under the scenarios we examined. In contrast, projected large reductions in wintering grounds precipitation caused the population to decline, with risk of extinction magnified when breeding habitat quantity or quality also decreased. Our study indicates that probability of long‐term persistence for Kirtland's Warbler will depend on climate change impacts to wintering grounds habitat quality and contributes to the growing literature documenting the importance of considering the full annual cycle for understanding population dynamics of migratory species., We sought to quantify the vulnerability of the rare Neotropical migratory songbird Kirtland's Warbler to projected environmental changes on the breeding and wintering grounds. We simulated independent and additive effects of reduced breeding grounds habitat quantity and quality, and wintering grounds habitat quality, on population viability. Projected large reductions in wintering grounds precipitation caused the population to decline, with risk of extinction magnified when breeding habitat quantity or quality also decreased.
- Published
- 2019
25. Response to Letter to Editor 'Comments on ‘Cell regulation of collagen fibril macrostructure during corneal morphogenesis’ by Koudouna et al.'
- Author
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Robert D. Young, Donald J. Brown, Eric Mikula, James V. Jester, Andrew J. Quantock, and Elena Koudouna
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Biomaterials ,Chemistry ,Biomedical Engineering ,Cell regulation ,Morphogenesis ,General Medicine ,Molecular Biology ,Biochemistry ,Biotechnology ,Collagen fibril ,Cell biology - Published
- 2021
26. Managing forest habitat for conservation-reliant species in a changing climate: The case of the endangered Kirtland’s Warbler
- Author
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Deahn M. Donner, Christine A. Ribic, Donald J. Brown, Mark D. Nelson, and Tim Greco
- Subjects
0106 biological sciences ,010504 meteorology & atmospheric sciences ,Ecology ,Endangered species ,Forestry ,Context (language use) ,Management, Monitoring, Policy and Law ,010603 evolutionary biology ,01 natural sciences ,Warbler ,Conservation reliant species ,Geography ,Species of concern ,Nest ,Habitat ,Regeneration (ecology) ,0105 earth and related environmental sciences ,Nature and Landscape Conservation - Abstract
Conservation and recovery of species of concern necessitates evaluating forest habitat conditions under changing climate conditions, especially in the early stages of the delisting process. Managers must weigh implications of near-term habitat management activities within the context of changing environmental conditions and a species’ biological traits that may influence their vulnerability to changing conditions. Here we applied established population-habitat relationships based on decades of monitoring and research-management collaborations for the Kirtland’s Warbler (Setophaga kirtlandii) to project potential impacts of changing environmental conditions to breeding habitat distribution, quantity, and quality in the near future. Kirtland’s warblers are habitat-specialists that nest exclusively within dense jack pine (Pinus banksiana) forests between ca. 5–20 years of age. Using Random Forests to predict changes in distribution and growth rate of jack pine under future scenarios, results indicate the projected distribution of jack pine will contract considerably (ca. 75%) throughout the Lake States region, U.S.A. in response to projected environmental conditions in 2099 under RCP 4.5 and 8.5 climate scenarios regardless of climate model. Reduced suitability for jack pine regeneration across the Lake States may constrain management options, especially for creating high stem-density plantations nesting habitat. However, conditions remain suitable for jack pine regeneration within their historical and current core breeding range in northern Lower Michigan and several satellite breeding areas. Projected changes in jack pine growth rates varied within the core breeding area, but altered growth rates did not greatly alter the duration that habitat remained suitable for nesting by the Kirtland’s Warblers. These findings contribute to Kirtland’s Warbler conservation by informing habitat spatial planning of plantation management to provide a constant supply of nesting habitat based on the spatial variability of potential loss or gain of lands environmentally suitable for regenerating jack pine in the long-term.
- Published
- 2018
27. Collagen fiber crimping following in vivo UVA-induced corneal crosslinking
- Author
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James V. Jester, Donald J. Brown, Eric Mikula, Samantha Bradford, and Tibor Juhasz
- Subjects
0301 basic medicine ,Keratoconus ,medicine.medical_specialty ,Ultraviolet Rays ,Corneal Stroma ,Riboflavin ,In vivo confocal microscopy ,Corneal crosslinking ,Medical Biochemistry and Metabolomics ,Eye ,Ophthalmology & Optometry ,Corneal collagen ,Article ,Epithelium ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,Nonlinear optical ,0302 clinical medicine ,Opthalmology and Optometry ,In vivo ,Collagen fiber ,Ophthalmology ,Cornea ,medicine ,Animals ,Eye Disease and Disorders of Vision ,Photosensitizing Agents ,Corneal Haze ,Chemistry ,Epithelium, Corneal ,Neurosciences ,Corneal ,Corneal imaging ,medicine.disease ,eye diseases ,Sensory Systems ,Autofluorescence ,Cross-Linking Reagents ,030104 developmental biology ,medicine.anatomical_structure ,030221 ophthalmology & optometry ,Rabbits ,Collagen ,sense organs - Abstract
The purpose of this study was to measure collagen fiber crimping (CFC) using nonlinear optical imaging of second harmonic generated (SHG) signals to determine the effects of UVA-riboflavin induced corneal collagen crosslinking (UVA CXL) on collagen structure. Two groups, four rabbits each, were treated in the right eye with standard UVA CXL. In vivo confocal microscopy was performed at 1, 2, and 4 weeks after treatment for the first group and up to three months for the second group to measure epithelial/stromal thickness and corneal haze during recovery. Rabbits were sacrificed at one and three months, respectively, and their corneas fixed under pressure. Regions of crosslinking were identified by the presence of collagen autofluorescence (CAF) and then collagen structure was imaged using SHG microscopy. The degree of CFC was determined by measuring the percentage difference between the length of the collagen fiber and the linear distance traveled. CFC was measured in the central anterior and posterior CXL region, the peripheral non-crosslinked region in the same cornea, and the central cornea of the non-crosslinked contralateral eye. No change in corneal thickness was detected after one month, however the stromal thickness surpassed its original baseline thickness at three months by 25.9 μm. Corneal haze peaked at one month and then began to clear. Increased CAF was detected in all CXL corneas, localized to the anterior stroma and extending to 42.4 ± 3.4% and 47.7 ± 7.6% of the corneal thickness at one and three months. There was a significant (P
- Published
- 2018
28. Evaluating the effect of expert elicitation techniques on population status assessment in the face of large uncertainty
- Author
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Jennifer F. Moore, Julien Martin, Hardin Waddle, Evan H. Campbell Grant, Jill Fleming, Eve Bohnett, Thomas S.B. Akre, Donald J. Brown, Michael T. Jones, Jessica R. Meck, Kevin Oxenrider, Anthony Tur, Lisabeth L. Willey, and Fred Johnson
- Subjects
Environmental Engineering ,Data Collection ,Uncertainty ,Animals ,General Medicine ,Management, Monitoring, Policy and Law ,Waste Management and Disposal ,Turtles - Abstract
Population projection models are important tools for conservation and management. They are often used for population status assessments, for threat analyses, and to predict the consequences of conservation actions. Although conservation decisions should be informed by science, critical decisions are often made with very little information to support decision-making. Conversely, postponing decisions until better information is available may reduce the benefit of a conservation decision. When empirical data are limited or lacking, expert elicitation can be used to supplement existing data and inform model parameter estimates. The use of rigorous techniques for expert elicitation that account for uncertainty can improve the quality of the expert elicited values and therefore the accuracy of the projection models. One recurring challenge for summarizing expert elicited values is how to aggregate them. Here, we illustrate a process for population status assessment using a combination of expert elicitation and data from the ecological literature. We discuss the importance of considering various aggregation techniques, and illustrate this process using matrix population models for the wood turtle (Glyptemys insculpta) to assist U.S. Fish and Wildlife Service decision-makers with their Species Status Assessment. We compare estimates of population growth using data from the ecological literature and four alternative aggregation techniques for the expert-elicited values. The estimate of population growth rate based on estimates from the literature (λ
- Published
- 2022
29. Hand-drawn Symbol Recognition of Surgical Flowsheet Graphs with Deep Image Segmentation
- Author
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Donald J. Brown, Angela Yi, William Adorno, and Marcel E. Durieux
- Subjects
Computer science ,business.industry ,Template matching ,Deep learning ,Value (computer science) ,020206 networking & telecommunications ,Pattern recognition ,02 engineering and technology ,Image segmentation ,Symbol (chemistry) ,Approximation error ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Segmentation ,Artificial intelligence ,business ,Digitization - Abstract
Perioperative data are essential to investigating the causes of adverse surgical outcomes. In some low to middle income countries, these data are computationally inaccessible due to a lack of digitization of surgical flowsheets. In this paper, we present a deep image segmentation approach using a U-Net architecture that can detect hand-drawn symbols on a flowsheet graph. The segmentation mask outputs are post-processed with techniques unique to each symbol to convert into numeric values. The U-Net method can detect, at the appropriate time intervals, the symbols for heart rate and blood pressure with over 99 percent accuracy. Over 95 percent of the predictions fall within an absolute error of five when compared to the actual value. The deep learning model outperformed template matching even with a small size of annotated images available for the training set.
- Published
- 2020
30. Eicosapentaenoic acid (EPA) activates PPARγ signaling leading to cell cycle exit, lipid accumulation, and autophagy in human meibomian gland epithelial cells (hMGEC)
- Author
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Yilu Xie, Chang Rae Rho, Richard C. Prince, James V. Jester, Eric O. Potma, Jinseor Kim, Khawla Mustafa, Donald J. Brown, and Sun Woong Kim
- Subjects
0301 basic medicine ,PPARγ ,1.1 Normal biological development and functioning ,Peroxisome proliferator-activated receptor ,Ophthalmology & Optometry ,Article ,PPAR agonist ,03 medical and health sciences ,0302 clinical medicine ,Cyclin D1 ,Downregulation and upregulation ,Underpinning research ,Opthalmology and Optometry ,Lipid droplet ,Autophagy ,Humans ,Cancer ,chemistry.chemical_classification ,Cell cycle exit ,Cell Cycle ,Meibomian Glands ,Lipid metabolism ,Epithelial Cells ,Cell cycle ,Cell biology ,Meibocyte ,PPAR gamma ,Human meibomian gland epithelial cell ,Ophthalmology ,030104 developmental biology ,chemistry ,Eicosapentaenoic Acid ,030221 ophthalmology & optometry ,lipids (amino acids, peptides, and proteins) - Abstract
PurposeThe purpose of this study was to access the ability of the natural PPAR agonist, eicosapentaenoic acid (EPA), to activate PPAR gamma (γ) signaling leading to meibocyte differentiation in human meibomian gland epithelial cell (hMGEC).MethodsHMGEC were exposed to EPA, alone and in combination with the specific PPARγ antagonist, T0070907, to selectively block PPARγ signaling. Expression of PPARγ response genes were evaluated by qPCR. Effect on cell cycle was evaluated using Ki-67 labelling and western blots. During differentiation, autophagy was monitored using the Autophagy Tandem Sensor (ATS) and LysoTracker. Lipid accumulation was characterized by Stimulated Raman Scattering microscopy (SRS) and neutral lipid staining in combination with ER-Tracker, LysoTracker, and ATS. Autophagy was also investigated using western blotting. Seahorse XF analysis was performed to monitor mitochondrial function.ResultsEPA specifically upregulated expression of genes related to lipid synthesis and induced cell cycle exit through reduced cyclin D1 expression and increased p21 and p27 expression. EPA also induced accumulation of lipid droplets in a time and dose dependent manner (P 
- Published
- 2020
31. A comprehensive framework for handling location error in animal tracking data
- Author
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Ronald Moen, Koji Yamazaki, Kamran Safi, Kristie A. Stein, Tom S. B. Akre, Alexandre Roulin, Nicholas P. Gould, Jared A. Stabach, Jill M. Shephard, Justin M. Calabrese, Nandintsetseg Dejid, Christopher M. Tonra, Yayoi Kaneko, Thomas Pfeiffer, Robin Séchaud, J.N. Dunlop, Vickie DeNicola, Shaun S. Killen, Michael J. Noonan, Kyana N. Pike, Donald J. Brown, Christopher S. DePerno, Roland Kays, Jack Hollins, Madaline M. Cochrane, Christen H. Fleming, Tricia A. Miller, Emília Patrícia Medici, Anne K. Scharf, Sergio A. Lambertucci, William F. Fagan, Hiroaki Ishii, Bernd-U. Meyburg, Barbara Koeck, Thomas Mueller, Scott D. LaPoint, and Jonathan Drescher-Lehman
- Subjects
Schedule ,Computer science ,business.industry ,Inference ,Estimator ,computer.software_genre ,Visualization ,Global Positioning System ,Relevance (information retrieval) ,Anomaly detection ,Data mining ,Scale (map) ,business ,computer - Abstract
Animal tracking data are being collected more frequently, in greater detail, and on smaller taxa than ever before. These data hold the promise to increase the relevance of animal movement for understanding ecological processes, but this potential will only be fully realized if their accompanying location error is properly addressed. Historically, coarsely-sampled movement data have proved invaluable for understanding large scale processes (e.g., home range, habitat selection, etc.), but modern fine-scale data promise to unlock far more ecological information. While GPS location error can often be ignored in coarsely sampled data, fine-scale data require more care, and tools to do this have not kept pace. Current approaches to dealing with location error largely fall into two categories—either discarding the least accurate location estimates prior to analysis or simultaneously fitting movement and error parameters in a hidden-state model. In some cases these approaches can provide a level of correction, but they have known limitations, and in some cases they can be worse than doing nothing. Here, we provide a general framework to account for location error in the analysis of triangulated and trilatcralizcd animal tracking data, which includes GPS, Argos Doppler-shift, triangulated VHF, trilatcralized acoustic and cellular location data. We apply our error-modelselection framework to 190 GPS, cellular, and acoustic devices representing 27 models from 14 manufacturers. Collectively, these devices were used to track a wide range of taxa comprising birds, fish, reptiles, and mammals of different sizes and with different behaviors, in urban, suburban, and wild settings. In almost half of the tested device models, error-model selection was necessary to obtain the best performing error model, and in almost a quarter of tested device models, the reported DOP values were actually misinformative. Then, using empirical tracking data from multiple species, we provide an overview of modern, error-informed movement analyses, including continuous-time path reconstruction, home-range distribution, home-range overlap, speed, and distance estimation. Adding to these techniques, we introduce new error-informed estimators for outlier detection and autocorrelation visualization. Because error-induced biases depend on many factors—sampling schedule, movement characteristics, tracking device, habitat, etc.—differential bias can easily confound biological inference and lead researchers to draw false conclusions. We demonstrate how error-informed analyses on calibrated tracking data can provide more accurate estimates are that are insensitive to location error, and allow researchers to use all of their data.
- Published
- 2020
32. HMIC: Hierarchical Medical Image Classification, A Deep Learning Approach
- Author
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Rasoul Sali, Kamran Kowsari, Beatrice Amadi, Donald J. Brown, William Adorno, Sana Syed, Lubaina Ehsan, Paul Kelly, Sean R. Moore, and Asad Ali
- Subjects
FOS: Computer and information sciences ,Computer Science - Machine Learning ,Computer Science - Artificial Intelligence ,Computer science ,Computer Vision and Pattern Recognition (cs.CV) ,Big data ,Computer Science - Computer Vision and Pattern Recognition ,medical imaging ,Machine Learning (stat.ML) ,02 engineering and technology ,computer.software_genre ,hierarchical medical image classification ,Field (computer science) ,Article ,Machine Learning (cs.LG) ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Statistics - Machine Learning ,deep Learning ,FOS: Electrical engineering, electronic engineering, information engineering ,0202 electrical engineering, electronic engineering, information engineering ,Medical imaging ,deep Learning, hierarchical classification, hierarchical medical image classification, medical imaging ,Hierarchy ,lcsh:T58.5-58.64 ,Contextual image classification ,lcsh:Information technology ,business.industry ,Deep learning ,Image and Video Processing (eess.IV) ,Information processing ,Electrical Engineering and Systems Science - Image and Video Processing ,hierarchical classification ,Comprehension ,Artificial Intelligence (cs.AI) ,020201 artificial intelligence & image processing ,Artificial intelligence ,business ,computer ,Natural language processing ,Information Systems - Abstract
Image classification is central to the big data revolution in medicine. Improved information processing methods for diagnosis and classification of digital medical images have shown to be successful via deep learning approaches. As this field is explored, there are limitations to the performance of traditional supervised classifiers. This paper outlines an approach that is different from the current medical image classification tasks that view the issue as multi-class classification. We performed a hierarchical classification using our Hierarchical Medical Image classification (HMIC) approach. HMIC uses stacks of deep learning models to give particular comprehension at each level of the clinical picture hierarchy. For testing our performance, we use biopsy of the small bowel images that contain three categories in the parent level (Celiac Disease, Environmental Enteropathy, and histologically normal controls). For the child level, Celiac Disease Severity is classified into 4 classes (I, IIIa, IIIb, and IIIC).
- Published
- 2020
33. A novel transillumination meibography device for in vivo imaging of mouse meibomian glands
- Author
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Ho Sik Hwang, Donald J. Brown, Yilu Xie, James V. Jester, and Eric Mikula
- Subjects
0301 basic medicine ,Male ,medicine.medical_specialty ,Meibomian gland ,Transillumination ,03 medical and health sciences ,Broad spectrum ,Mice ,0302 clinical medicine ,Light source ,stomatognathic system ,Ophthalmology ,medicine ,Animals ,Mice, Inbred BALB C ,business.industry ,Meibomian gland dysfunction ,Meibomian Glands ,body regions ,030104 developmental biology ,medicine.anatomical_structure ,Low light level ,Tears ,030221 ophthalmology & optometry ,Eyelid Diseases ,sense organs ,Eyelid ,business ,Preclinical imaging - Abstract
Purpose While mouse models of dry eye disease (DED) have been developed, studies evaluating the role of the meibomian glands limited by the inability to temporally document changes. In this report we describe the development of a novel mouse transillumination meibography device and assess the ability of this device to detect age-related changes in the meibomian glands of young and old mice. Methods The mouse meibography device was comprised of a 3 mm wide right angle prism attached to broad spectrum light source by an optical fiber. Eyelids were then pulled over the prism using double tooth forceps and imaged using a stereomicroscope and low light level camera. Meibomian glands from four young and four old male, BALB/c mice were then imaged and analyzed using ImageJ. Results In young mice, meibography documented the presence of 7–8 meibomian glands appearing as black and distinct eyelid structures with the length shorter in the lower eyelid compared to the upper eyelids. Eyelids of old mice showed apparent dropout of meibomian glands along with smaller and more irregularly shaped acini. The mean acini area of one meibomian gland was 0.088 ± 0.025 mm2 in young mice and 0.080 ± 0.020 mm2 in old mice (p = 0.564), but the Meibomian gland density was significantly lower in older mice (41.7 ± 6.4%, 27.3 ± 4.2%) (p = 0.021). Conclusion We have developed an in vivo meibography device that may prove useful in sequentially documenting changes during development of meibomian gland dysfunction and following treatment.
- Published
- 2020
34. Enhanced Transepithelial Riboflavin Delivery Using Femtosecond Laser-Machined Epithelial Microchannels
- Author
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James V. Jester, Yilu Xie, Donald J. Brown, Tibor Juhasz, Samantha Bradford, and Eric Mikula
- Subjects
Stromal cell ,Materials science ,Riboflavin ,Corneal collagen cross-linking ,Biomedical Engineering ,Organ culture ,Eye ,Article ,Epithelium ,Cornea ,Benzalkonium chloride ,femtosecond laser ,Opthalmology and Optometry ,medicine ,Animals ,crosslinking ,Eye Disease and Disorders of Vision ,Corneal epithelium ,Photosensitizing Agents ,Lasers ,Epithelium, Corneal ,Corneal ,Penetration (firestop) ,eye diseases ,Ophthalmology ,medicine.anatomical_structure ,nonlinear ,sense organs ,Rabbits ,medicine.drug ,Biomedical engineering - Abstract
Author(s): Bradford, Samantha; Mikula, Eric; Xie, Yilu; Juhasz, Tibor; Brown, Donald J; Jester, James V | Abstract: PurposeThis study describes a femtosecond laser (FS) approach to machine corneal epithelial microchannels for enhancing riboflavin (Rf) penetration into the cornea prior to corneal crosslinking (CXL).MethodsUsing a 1030-nm FS laser with 5- to 10-µJ pulse energy, the corneal epithelium of slaughterhouse rabbit eyes was machined to create 2-µm-diameter by 25-µm-long microchannels at a density of 100 or 400 channels/mm2. Rf penetration through the microchannels was then determined by applying 1% Rf in phosphate-buffered saline for 30 minutes followed by removal of the cornea and extraction from the central stromal button. Stromal Rf concentrations were then compared to those obtained using standard epithelial debridement or 0.01% benzalkonium chloride (BAK) to disrupt the epithelial barrier.ResultsMicrochannels formed using a 5-µJ/pulse at a density of 400 channels/mm2 achieved a stromal Rf concentration that was 50% of that achieved by removal of the corneal epithelium and imbibing with 1% Rf. Stromal Rf levels were also equal to that of debrided corneas soaked with 0.5% Rf, threefold higher than those soaked with 0.1% Rf, and twofold higher than corneas soaked in BAK without epithelial debridement. Organ culture of treated corneas showed a normal corneal epithelium following FS machining while BAK-treated corneas showed extensive epithelial and stromal damage at 24 hours posttreatment.ConclusionsFS corneal epithelial machining can be used to enhance penetration of Rf into the stroma for corneal CXL.Translational relevanceThe creation of epithelial microchannels allows for stromal Rf concentrations high enough to perform true transepithelial crosslinking.
- Published
- 2020
35. Approximate Solutions of Walrasian and Gorman Polar Form Equilibrium Inequalities
- Author
-
Donald J. Brown
- Subjects
Computer Science::Computer Science and Game Theory ,General equilibrium theory ,Degree (graph theory) ,Gorman polar form ,Uniform boundedness ,Algorithmic game theory ,Mathematical economics ,Time complexity ,Integer programming ,Computer Science::Computers and Society ,Dual (category theory) ,Mathematics - Abstract
Recently Cherchye et al. (2011) reformulated the Walrasian equilibrium inequalities, introduced by Brown and Matzkin (1996), as an integer programming problem and proved that solving the Walrasian equilibrium inequalities is NP-hard. Following Brown and Shannon (2000), we reformulate the Walrasian equilibrium inequalities as the dual Walrasian equilibrium inequalities. Brown and Shannon proved that the Walrasian equilibrium inequalities are solvable iff the dual Walrasian equilibrium inequalities are solvable. We show that solving the dual Walrasian equilibrium inequalities is equivalent to solving a NP-hard minimization problem. Approximation theorems are polynomial time algorithms for computing approximate solutions of NP-hard minimization problems. The primary contribution of this paper is an approximation theorem for the equivalent NP-hard minimization problem. In this theorem, we propose a polynomial time algorithm for computing an approximate solution to the dual Walrasian equilibrium inequalities, where the marginal utilities of income are uniformly bounded. We derive explicit bounds on the degree of approximation from observable market data. The second contribution is the derivation of the Gorman polar form equilibrium inequalities for an exchange economy, where each consumer is endowed with an indirect utility function in Gorman polar form. If the marginal utilities of income are uniformly bounded then we prove a similar approximation theorem for the Gorman polar form equilibrium inequalities.
- Published
- 2020
36. Approximate Solutions of Walrasian Equilibrium Inequalities with Bounded Marginal Utilities of Income
- Author
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Donald J. Brown
- Subjects
Computer Science::Computer Science and Game Theory ,General equilibrium theory ,Degree (graph theory) ,Bounded function ,Applied mathematics ,Observable ,Algorithmic game theory ,Integer programming ,Time complexity ,Mathematics ,Dual (category theory) - Abstract
Recently Cherchye et al. (2011) reformulated the Walrasian equilibrium inequalities, introduced by Brown and Matzkin (1996), as an integer programming problem and proved that solving the Walrasian equilibrium inequalities is NP-hard. Brown and Shannon (2002) derived an equivalent system of equilibrium inequalities,i.e., the dual Walrasian equilibrium inequalities. That is, the Walrasian equilibrium inequalities are solvable iff the dual Walrasian equilibrium inequalities are solvable. We show that solving the dual Walrsian equilibrium inequalities is equivalent to solving a NP-hard minimization problem. Approximation theorems are polynomial time algorithms for computing approximate solutions of NP-hard minimization problems. The primary contribution of this paper is an approximation theorem for the equivalent NP-hard minimization problem. In this theorem, we derive explicit bounds, where the degree of approximation is determined by observable market data.
- Published
- 2020
37. Introduction
- Author
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Donald J. Brown
- Published
- 2020
38. Affective Portfolio Analysis: Risk, Ambiguity and (IR)rationality
- Author
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Donald J. Brown
- Subjects
Microeconomics ,Prospect theory ,Portfolio insurance ,Fiat money ,Economics ,Ambiguity aversion ,Portfolio investment ,Hedge (finance) ,Modern portfolio theory ,Expected utility hypothesis - Abstract
Ambiguous assets are characterized as assets where objective and subjective probabilities of tomorrow’s asset-returns are ill- defined or may not exist, e.g., bitcoin, volatility indices or any IPO. Investors may choose to diversify their portfolios of fiat money, stocks and bonds by investing in ambiguous assets, a fourth asset class, to hedge the uncertainties of future returns that are not risks. (IR)rational probabilities are computable alternative descriptions of the distribution of returns for ambiguous assets. (IR)rational probabilities can be used to define an investor’s (IR)rational expected utility function in the class of non-expected utilities. Investment advisors use revealed preference analysis to elicit the investor’s composite preferences for risk tolerance, ambiguity aversion and optimism. Investors rationalize (IR)rational expected utilities over portfolios of fiat money, stocks, bonds and ambiguous assets by choosing their optimal portfolio investments with (IR)rational expected utilities. Subsequently, investors can hedge future losses of their optimal portfolios by purchasing minimum-cost portfolio insurance.
- Published
- 2020
39. Affective Decision Making Under Uncertainty
- Author
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Donald J. Brown
- Published
- 2020
40. The Ambiguity of Black Swans
- Author
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Donald J. Brown
- Subjects
Contingency table ,Core (game theory) ,Status quo ,Prospect theory ,media_common.quotation_subject ,Statistics ,Ambiguity ,Certainty effect ,Row ,Black swan theory ,media_common ,Mathematics - Abstract
The fourfold pattern of decision-making under risk, discussed in (Kahneman 2011), is described by the author as “one of the core achievements of prospect theory”. It is a 2 × 2 contingency table, where the columns are high probability, the certainty effect, and low probability, the possibility effect, and the rows are gains and losses from a given status quo.
- Published
- 2020
41. Computational Complexity of the Walrasian Equilibrium Inequalities
- Author
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Donald J. Brown
- Subjects
Computer Science::Computer Science and Game Theory ,General equilibrium theory ,Computational complexity theory ,Inequality ,media_common.quotation_subject ,Mathematical economics ,Integer programming ,Computer Science::Computers and Society ,media_common ,Mathematics - Abstract
Recently Cherchye et al. (2011) reformulated the Walrasian equilibrium inequalities, introduced by (Brown and Matzkin,.Econometrica 64:1249–1262, 1996), as an integer programming problem and proved that solving the Walrasian equilibrium inequalities is NP-hard. Following (Brown and Shannon,.Econometrica 68:1529–1539, 2000), we reformulate the Walrasian equilibrium inequalities as the Hicksian equilibrium inequalities.
- Published
- 2020
42. Long-term occupancy dynamics of the threatened Cheat Mountain salamander and its competitors in relation to linear habitat fragmentation
- Author
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Lacy E. Rucker, Thomas K. Pauley, Donald J. Brown, and Mark B. Watson
- Subjects
Habitat fragmentation ,Ecology ,Plethodon nettingi ,fungi ,Fragmentation (computing) ,Forestry ,Plethodon wehrlei ,Management, Monitoring, Policy and Law ,Biology ,biology.organism_classification ,Habitat destruction ,Habitat ,Plethodon cinereus ,biology.animal ,Salamander ,human activities ,Nature and Landscape Conservation - Abstract
Amphibians are declining globally and while many factors are contributing to this decline, habitat loss and degradation caused by climate and land use changes are among the most critical. Habitat degradation and increased interspecific competition are both concerns for long-term viability of the federally-threatened Cheat Mountain salamander (Plethodon nettingi) which is endemic to high elevations in West Virginia. In this study, we quantified the impacts of linear habitat fragmentation (i.e., a linear forest clearing for creation of a ski slope) on local colonization and extinction probabilities in adjacent forested habitat for the Cheat Mountain salamander and two co-occurring competitor species, eastern red-backed salamander (Plethodon cinereus) and Wehrle’s salamander (Plethodon wehrlei). We also quantified long-term changes in total occupancy of the species within the high elevation study area. We surveyed the salamander community annually from 1988 to 2021 using diurnal natural cover object searches at 43 plots, with 1988 representing three years following linear habitat fragmentation. For each species, we used dynamic occupancy models to identify and model influential covariates for initial occupancy, colonization, extinction, and detection probability. We found that distance to fragmentation was positively correlated with colonization probability for Cheat Mountain salamanders, indicating negative edge effects of the linear forest clearing. Distance to fragmentation was negatively correlated with colonization probability for eastern red-backed salamanders, potentially indicating this species benefited from increased solar radiation or reduced competition from Cheat Mountain salamanders. Predicted occupancy of eastern red-backed salamanders and Wehrle’s salamanders increased over the 34 year monitoring period, indicating potential for increased competitive interactions. Our study suggests that extensive linear habitat fragmentation could result in degraded habitat for Cheat Mountain salamanders in the adjacent forest, and that potential for interactions with competitor species is increasing in high elevation forest stands.
- Published
- 2022
43. PPARγ regulates meibocyte differentiation and lipid synthesis of cultured human meibomian gland epithelial cells (hMGEC)
- Author
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Donald J. Brown, Sun Woong Kim, Paul Nguyen, James V. Jester, Yilu Xie, Vickie T. Bui, Jonathan S. Kang, and Kelly Do Huynh
- Subjects
0301 basic medicine ,Cells ,1.1 Normal biological development and functioning ,Cell ,Peroxisome proliferator-activated receptor ,Ophthalmology & Optometry ,PPAR ,Article ,Rosiglitazone ,03 medical and health sciences ,0302 clinical medicine ,Downregulation and upregulation ,Underpinning research ,Opthalmology and Optometry ,Lipid droplet ,medicine ,Humans ,Cells, Cultured ,chemistry.chemical_classification ,Cultured ,MGD ,Lipogenesis ,Meibomian Glands ,Cell Differentiation ,Epithelial Cells ,Lipid metabolism ,Cell cycle ,Lipids ,Meibocyte ,Cell biology ,PPAR gamma ,Ophthalmology ,030104 developmental biology ,medicine.anatomical_structure ,chemistry ,Meibomian gland ,030221 ophthalmology & optometry ,medicine.drug - Abstract
PURPOSE: To evaluate the role of PPARγ in regulating meibocyte differentiation and lipid synthesis in a human meibomian gland epithelial cell line (hMGEC). METHODS: HMGEC were exposed to the PPARγ agonist, Rosiglitazone, from 10–50 μM. Cultures were also exposed to specific PPARγ antagonist, T0070907, to block PPARγ receptor signaling. Cells were then stained with Ki-67 and LipidTox to determine the effects on cell cycling and lipid synthesis, respectively. Expression of meibocyte differentiation related proteins, ADFP, PPARγ, ELOVL4, and FABP4, were evaluated by quantitative PCR and western blotting. A human corneal epithelial cell line (hTCEpi) was used as a control. RESULT: Rosiglitazone significantly decreased Ki-67 staining within 2 days in a dose-dependent manner (P = 0.003) and increased lipid accumulation in hMGEC in a dose dependent manner. T0070907 suppressed both lipid droplet synthesis and cell cycle exit. Rosiglitazone significantly upregulated expression of ADFP, PPARγ, ELOVL4, and FABP4 by 9.6, 2.7, 2.6, and 3.3 fold on average (all P < 0.05 except for FABP4, P = 0.057) in hMGEC. T0070907 significantly abrogated rosiglitazone-induced upregulation of these genes when treated prior to rosiglitazone treatment (all P < 0.05). The observed lipogenic differentiation response was not duplicated in hTCEpi after exposure to rosiglitazone. CONCLUSION: Rosiglitazone induced cell cycle exit and upregulation of lipogenic gene expression leading to lipid accumulation in hMGEC. These effects were suppressed by PPARγ antagonist indicating that PPARγ signaling specifically directs lipogenesis in hMGEC. These findings suggest that PPARγ plays a critical role in meibocyte differentiation.
- Published
- 2018
44. Light transmission/absorption characteristics of the meibomian gland
- Author
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James V. Jester, Donald J. Brown, Kyung-Sun Na, Yilu Xie, Young-Sik Yoo, Suk-Woo Yang, Ho Sik Hwang, and Elena Koudouna
- Subjects
0301 basic medicine ,Infrared Rays ,Tarsus (eyelids) ,Meibomian gland ,Diagnostic Techniques, Ophthalmological ,Article ,Light scattering ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Nuclear magnetic resonance ,Dermis ,Microscopy ,medicine ,Animals ,Humans ,Paraformaldehyde ,Analysis of Variance ,Bright-field microscopy ,Meibomian Glands ,Ophthalmology ,030104 developmental biology ,medicine.anatomical_structure ,chemistry ,030221 ophthalmology & optometry ,Rabbits ,Eyelid - Abstract
PURPOSE: While meibography has proven useful in identifying structural changes in the meibomian gland (MG), little is known regarding the MG spectral transmission and absorption characteristics. The purpose of this study was to measure the transmission/absorption spectra of the MG compared to other eyelid tissues. METHODS: Human and rabbit eyelids were fixed in paraformaldehyde, serial sectioned (50 μm) using a cryotome and imaged by brightfield and reflectance microscopy. Eyelid regions (MG, muscle, tarsus and dermis) were then illuminated by a 100 μm spot using a infrared enhanced white light source. Transmission spectra over a 550–950 nm range were then measured using a spectrometer and differences compared using two-way analysis of variance. RESULTS: Brightfield microscopy of both human and rabbit eyelid tissue showed a marked decrease in light transmission for MG acini compared to other eyelid tissues. In rabbit, the dermis showed 5 × and the muscle showed 2 × more light transmission compared to MG (P < .001 and P < .001, respectively). For human, the muscle showed 14 × and the tarsus showed 84 × more light transmission compared to MG (P < .01 and P < .001, respectively). No specific spectral region of light absorption could be detected in either rabbit or human MG. Loss of light transmission in MG was localized to acini containing small lipid droplets, averaging 2.7 ± 0.8 μm in diameter. CONCLUSIONS: The data suggest that light transmission is dramatically reduced in the acini due to light scattering by small lipid droplets, suggesting that Meibography detects active lipid synthesis in differentiating meibocytes.
- Published
- 2018
45. Effects of an Extreme Flood Event on Federally Endangered Diamond Darter Abundances
- Author
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Donald J. Brown, Patricia A. Thompson, Austin A. Rizzo, Christopher T. Rota, and Stuart A. Welsh
- Subjects
0106 biological sciences ,Hydrology ,biology ,Flood myth ,Crystallaria cincotta ,010604 marine biology & hydrobiology ,fungi ,Rare species ,Endangered species ,Small population size ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Darter ,Habitat ,Abundance (ecology) ,parasitic diseases ,Environmental science ,Ecology, Evolution, Behavior and Systematics - Abstract
Extreme flood events can substantially affect riverine systems, modifying in-stream habitat and influencing fish assemblages and densities. Rare species are especially vulnerable to these disturbance events because of their small population size and often reduced phenotypic heterogeneity. In June 2016 the lower Elk River in West Virginia experienced severe flooding, resulting in a peak discharge that exceeded the 0.005 annual exceedance probability (>200 y flood) in the main stem. We obtained pre-flood and post-flood population count data and estimated abundances for one cohort of the federally endangered Diamond Darter (Crystallaria cincotta) at 15 sites. While both the total count data and total estimated abundance decreased following the flood, our analyses did not indicate the extreme flood event strongly impacted Diamond Darter abundance. This indicates individuals are able to withstand high velocities and resist displacement or mortality. In addition site-level abundances were estimated at three sentinel sites during 2015 and 2016 using a multinomial N-mixture model that accounted for variation in detectability resulting from water temperature. Mean estimated abundance varied among the three sites and between the 2 y. Our results suggest there is substantial variation in year-class strength between the two cohorts we sampled. It is suggested that survey efforts at established sentinel sites be continued on an annual basis in order to help determine factors influencing year-class strength.
- Published
- 2018
46. Response of Lizards to High-Severity Wildfires in a Southern United States Mixed Pine/Hardwood Forest
- Author
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Donald J. Brown, Michael R. J. Forstner, and Adam Duarte
- Subjects
0106 biological sciences ,Skink ,geography ,geography.geographical_feature_category ,biology ,Lizard ,Ecology ,010604 marine biology & hydrobiology ,Aquatic Science ,biology.organism_classification ,010603 evolutionary biology ,01 natural sciences ,Aspidoscelis sexlineata ,Ecoregion ,Abundance (ecology) ,biology.animal ,Spring (hydrology) ,Animal Science and Zoology ,High severity ,Ecology, Evolution, Behavior and Systematics ,Scincella - Abstract
High-severity forest fires are increasing in large areas of the southern and western United States as the climate becomes warmer and drier. Natural resource managers need a better understanding of the short- and long-term effects of wildfires on lizard populations, but there is a paucity of studies focused on lizard-wildfire relationships. We used a before-after, control-impact (BACI) sample design to assess the response of three lizard species—Six-lined Racerunner (Aspidoscelis sexlineata), Prairie Lizard (Sceloporus consobrinus), and Little Brown Skink (Scincella lateralis)—to high-severity wildfires that occurred in the Lost Pines Ecoregion, Texas, USA. Specifically, we analyzed monitoring data collected across 17 trapping sessions from spring 2008 to spring 2013 using stratified N-mixture models to estimate trends in lizard abundances, while accounting for environmental parameters that might influence lizard detectability. We found no evidence of a fire-induced change in abundance for any of the lizar...
- Published
- 2017
47. Responses of Terrestrial Herpetofauna to Persistent, Novel Ecosystems Resulting from Mountaintop Removal Mining
- Author
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Petra Bohall Wood, Donald J. Brown, and Jennifer M. Williams
- Subjects
0106 biological sciences ,geography ,geography.geographical_feature_category ,Ecology ,010603 evolutionary biology ,01 natural sciences ,Novel ecosystem ,Grassland ,Shrubland ,010601 ecology ,Mountaintop removal mining ,Surface mining ,Habitat ,Disturbance (ecology) ,Environmental science ,Soil horizon ,Animal Science and Zoology ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
Mountaintop removal mining is a large-scale surface mining technique that removes entire floral and faunal communities, along with soil horizons located above coal seams. In West Virginia, the majority of this mining occurs on forested mountaintops. However, after mining ceases the land is typically reclaimed to grasslands and shrublands, resulting in novel ecosystems. In this study, we examined responses of herpetofauna to these novel ecosystems 10–28 y postreclamation. We quantified differences in species-specific habitat associations, (sub)order-level abundances, and habitat characteristics in four habitat types: reclaimed grassland, reclaimed shrubland, forest fragments in mined areas, and nonmined intact forest. Habitat type accounted for 33.2% of the variation in species-specific captures. With few exceptions, forest specialists were associated with intact forest and fragmented forest sites, while habitat generalists were either associated with grassland and shrubland sites or were distributed among all habitat types. At the (sub)order level, salamander (Order Urodela) captures were highest at fragmented and intact forest sites, frog and toad (Order Anura) captures were lowest at intact forest sites, and snake (Suborder Serpentes) captures were highest at shrubland sites. Habitat type was a strong predictor for estimated total abundance of urodeles, but not for anurans or snakes. Tree stem densities in grasslands differed from the other three habitat types, and large trees (>38 cm diameter at breast height) were only present at forest sites. Overstory vegetation cover was greater in forested than in reclaimed habitat types. Ground cover in reclaimed grasslands was distinct from forest treatments with generally less woody debris and litter cover and more vegetative cover. It is important to consider the distributions of habitat specialists of conservation concern when delineating potential mountaintop mine sites, as these sites will likely contain unsuitable habitat for forest specialists for decades or centuries when reclaimed to grassland or shrubland.
- Published
- 2017
48. Factors Influencing Detection of the Federally Endangered Diamond Darter Crystallaria cincotta: Implications for Long-Term Monitoring Strategies
- Author
-
Stuart A. Welsh, Patricia A. Thompson, Donald J. Brown, and Austin A. Rizzo
- Subjects
0106 biological sciences ,education.field_of_study ,Ecology ,Crystallaria cincotta ,010604 marine biology & hydrobiology ,Population ,Endangered species ,Biology ,biology.organism_classification ,01 natural sciences ,Darter ,010601 ecology ,Habitat ,Long term monitoring ,education ,Ecology, Evolution, Behavior and Systematics - Abstract
Population monitoring is an essential component of endangered species recovery programs. The federally endangered Diamond Darter Crystallaria cincotta is in need of an effective monitoring design to improve our understanding of its distribution and track population trends. Because of their small size, cryptic coloration, and nocturnal behavior, along with limitations associated with current sampling methods, individuals are difficult to detect at known occupied sites. Therefore, research is needed to determine if survey efforts can be improved by increasing probability of individual detection. The primary objective of this study was to determine if there are seasonal and diel patterns in Diamond Darter detectability during population surveys. In addition to temporal factors, we also assessed five habitat variables that might influence individual detection. We used N-mixture models to estimate site abundances and relationships between covariates and individual detectability and ranked models using...
- Published
- 2017
49. Survey and analysis design for wood turtle population monitoring
- Author
-
Ronald Moen, Donald J. Brown, and Madaline M. Cochrane
- Subjects
0106 biological sciences ,Range (biology) ,Population ,010603 evolutionary biology ,01 natural sciences ,law.invention ,Abundance (ecology) ,law ,Wildlife management ,Turtle (robot) ,Transect ,education ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation ,General Environmental Science ,education.field_of_study ,Ecology ,biology ,Sampling (statistics) ,biology.organism_classification ,010601 ecology ,Fishery ,Geography ,General Earth and Planetary Sciences ,Glyptemys insculpta - Abstract
Population monitoring is a fundamental component of wildlife management, and is necessary to track site- and regional-level status and recovery of species of conservation concern. The wood turtle (Glyptemys insculpta) is a species of conservation concern for federal and state agencies because of population declines across the species' range. We developed and tested a survey and analysis design to assist agencies in the Upper Midwest, USA, with establishment of long-term monitoring programs for wood turtle populations. In spring of 2016, we conducted 8 replicate population surveys at 8 candidate long-term monitoring sites in northeastern Minnesota, USA. Using field survey data and simulation models, we assessed the influence of distance from river surveyed, number of survey replications, and number of sites on abundance estimates; we also delineated important survey covariates and compared demographic estimates based on distance from river surveyed. We estimated site-level abundances and compared survey designs using a multinomial N-mixture model that included a removal sampling observation process. Mean abundance estimates were similar when surveying 2 transects (i.e., the river-land interface to ~25m inland) or 4 transects (i.e., the river-land interface to ~55m inland), but decreasing the survey distance from river reduced the precision of estimates. Mean abundance estimates were similar with ?6 replications. Air temperature was an important predictor of survey-specific detection probability, with maximum detectability at 19-23?C. Sex ratio and mean carapace length did not differ based on whether we surveyed 2 or 4 transects, and percentage of individuals by size class was nearly identical between the sampling designs. Simulations indicated that 75% of mean abundance estimates were within ?8% of true abundance when ?15 sites were surveyed. The wood turtle survey and analysis design we developed and tested was effective for estimating abundance of wood turtle populations in northeastern Minnesota, and we encourage its use as a template for wood turtle monitoring programs in the Upper Midwest.
- Published
- 2017
50. Nonlinear Optical Corneal Crosslinking, Mechanical Stiffening, and Corneal Flattening Using Amplified Femtosecond Pulses
- Author
-
Sun Woong Kim, James V. Jester, Eric Mikula, Yilu Xie, Tibor Juhasz, Donald J. Brown, and Samantha Bradford
- Subjects
0301 basic medicine ,Keratoconus ,Materials science ,keratoconus ,Corneal collagen cross-linking ,Biomedical Engineering ,Bioengineering ,law.invention ,03 medical and health sciences ,Rare Diseases ,0302 clinical medicine ,law ,femtosecond laser ,Opthalmology and Optometry ,Cornea ,cornea ,medicine ,crosslinking ,myopia ,medicine.diagnostic_test ,Articles ,medicine.disease ,Corneal topography ,Laser ,Optical parametric amplifier ,eye diseases ,Numerical aperture ,Ophthalmology ,030104 developmental biology ,medicine.anatomical_structure ,Femtosecond ,030221 ophthalmology & optometry ,nonlinear ,sense organs ,Biomedical engineering - Abstract
Author(s): Bradford, Samantha; Mikula, Eric; Kim, Sun Woong; Xie, Yilu; Juhasz, Tibor; Brown, Donald J; Jester, James V | Abstract: Purpose:We have shown that nonlinear optical corneal crosslinking (NLO CXL) and stiffening can be achieved in ex vivo rabbit corneas using an 80-MHz, 760-nm femtosecond (FS) laser, however the required power was beyond the American National Standard Institute limit. The purpose of this study was to test the efficacy of amplified FS pulses to perform CXL to reduce power by increasing pulse energy. Methods:A variable numerical aperture laser scanning delivery system was coupled to a 1030-nm laser with a noncollinear optical parametric amplifier to generate 760 nm, 50 to 150 kHz amplified FS pulses with 79.5-μm axial and 2.9-μm lateral two-photon focal volume. Ex vivo rabbit corneas received NLO CXL, and effectiveness was assessed by measuring collagen autofluorescence (CAF) and mechanical stiffening. NLO CXL was also performed in 14 live rabbits, and changes in corneal topography were measured using an Orbscan. Results:Amplified pulses (0.3 μJ) generated significant CAF that increased logarithmically with decreasing scan speed; achieving equivalent CAF to UVA CXL at 15.5 mm/s. Indentation testing detected a 62% increase in stiffness compared to control, and corneal topography measurements revealed a significant decrease of 1.0 ± 0.8 diopter by 1 month (P l 0.05). Conclusions:These results show that NLO CXL using amplified pulses can produce corneal collagen CXL comparable to UVA CXL. Translational Relevance:NLO CXL using amplified pulses can produce corneal CXL comparable to UVA CXL, suggesting a potential clinical application in which NLO CXL can be used to perform personalized crosslinking for treatment of refractive errors and keratoconus.
- Published
- 2019
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