2016-2017 Open Access Publishing Fund
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Item Open Access The Valuation of an Equity-Linked Life Insurance Using the Theory of Indifference Pricing(2016-11-26) Choi, JungminItem Open Access The effects of an afterschool STEM program on students’ motivation and engagement(2017-06-12) Chittum, Jessica R.; Jones, Brett D.; Akalin, Sehmuz; Schram, Asta B.Background: One significant factor in facilitating students’ career intentions and persistence in STEM (science, technology, engineering, and mathematics) fields is targeting their interests and motivation before eighth grade. To reach students at this critical stage, a design-based afterschool STEM program, titled Studio STEM, was implemented to foster motivation and engagement in STEM topics and activities. The purpose of this study is twofold: (a) to investigate how Studio STEM affected students’ beliefs about science and whether these beliefs differed from their peers who did not participate in the program, and (b) to examine a case study of one Studio STEM implementation to investigate elements of the curriculum that motivated students to engage in the program. Results: After completing two Studio STEM programs, participants’ ratings of their values for science and science competence were higher than those of non participants. In addition, the Studio STEM participants’ motivational beliefs about science and intentions to pursue a college degree were more resilient over time than their peers. We also found that students could be motivated in a voluntary afterschool program (Studio STEM) in which they grappled with STEM concepts and activities, and could verbalize specific program elements that motivated them. Conclusions: Through this study, we found that students could be motivated in Studio STEM and that the experience had a positive impact on their perceptions about science as a field. Importantly, Studio STEM appeared to halt the decline in these students’ motivational beliefs about science that typically occurs during the middle school years, indicating that after school programs can be one way to help students maintain their motivation in science. Studying the program features that the students found motivating may help educators to make connections between research and theory, and their classroom instruction to motivate their students.Item Open Access Seasonal home range dynamics and sex differences in habitat use in a threatened, coastal marsh bird(2016-12-22) Kolts, Jaan Runyon; McRae, Susan B.A comprehensive understanding of spatiotemporal ecology is needed to develop conservation strategies for declining species. The king rail (Rallus elegans) is a secretive marsh bird whose range historically extended across the eastern United States. Inland migratory populations have been greatly reduced with most remaining populations inhabiting the coastal margins. Our objectives were to determine the migratory status of breeding king rails on the mid-Atlantic coast and to characterize home range size, seasonal patterns of movement, and habitat use. Using radiotelemetry, we tracked individual king rails among seasons, and established that at least a segment of this breeding population is resident. Mean (±SE) home range size was 19.8 ± 5.0 ha (95% kernel density) or 2.5 ± 0.9 (50% kernel density). We detected seasonal variation and sex differences in home range size and habitat use. In the nonbreeding season, resident male home ranges coincided essentially with their breeding territories. Overwintering males were more likely than females to be found in natural emergent marsh with a greater area of open water. Females tended to have larger home ranges than males during the nonbreeding season. We report for the first time the use of wooded natural marsh by overwintering females. Brood-rearing king rails led their young considerable distances away from their nests (average maximum distance: ~600 ± 200 m) and used both wooded natural and impounded marsh. King rails moved between natural marsh and managed impoundments during all life stages, but the proximity of these habitat types particularly benefitted brood-rearing parents seeking foraging areas with shallower water in proximity to cover. Our results demonstrate the importance of interspersion of habitat types to support resident breeders. Summer draining of impounded wetlands that are seasonally flooded for wintering waterfowl allows regrowth of vegetation and provides additional habitat at a critical time for wading birds.Item Open Access A high-efficiency CRISPR/Cas9 system for targeted mutagenesis in Cotton (Gossypium hirsutum L.)(2017-03-03) Zhang, Baohong; Li, Chao; Unver, TurgayThe complex allotetraploid genome is one of major challenges in cotton for repressing gene expression. Developing site-specific DNA mutation is the long-term dream for cotton breeding scientists. The clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) system is emerging as a robust biotechnology for targeted-DNA mutation. In this study, two sgRNAs, GhMYB25-like-sgRNA1 and GhMYB25-like-sgRNA2, were designed in the identical genomic regions of GhMYB25-like A and GhMYB25-like D, which were encoded by cotton A subgenome and the D subgenome, respectively, was assembled to direct Cas9-mediated allotetraploid cotton genome editing. High proportion (14.2–21.4%) CRISPR/Cas9-induced specific truncation events, either from GhMYB25-like A DNA site or from GhMYB25-like D DNA site, were detected in 50% examined transgenic cotton through PCR amplification assay and sequencing analyses. Sequencing results also demonstrated that 100% and 98.8% mutation frequency were occurred on GhMYB25-like-sgRNA1 and GhMYB25-like-sgRNA2 target site respectively. The off-target effect was evaluated by sequencing two putative off-target sites, which have 3 and 1 mismatched nucleotides with GhMYB25-like-sgRNA1 and GhMYB25-like-sgRNA2, respectively; all the examined samples were not detected any off-targetcaused mutation events. Thus, these results demonstrated that CRISPR/Cas9 is qualified for generating DNA level mutations on allotetraploid cotton genome with high-efficiency and high-specificity.Item Open Access A Content Analysis of Psychological Resilience Among First Responders and the General Population(2017-03) Crowe, Allison; Glass, J. Scott; Lancaster, Mandee F.; Raines, Justin M.; Waggy, Megan R.The current study examined how first responders and the general population described the concept of resilience. Categories of resilience were coded a priori using Stemler’s content analysis. For the general population, positive coping was the most frequently occurring category followed by social support and adaptability. The next most frequently occurring terms were societal resources and personal competence. Consistent with the general population, first responders described resilience most frequently with positive coping. Social support was the next most frequently occurring category, followed by personal competence, perseverance, emotional regulation, and physical fitness. Although both the general population and first responder participants highlighted the importance of having a support network, first responders suggested that dealing with traumatic experiences was more of an individual process, and seeking professional help was not common practice. Implications for mental health professionals and future directions for research are offered.Item Open Access Nearshore mixing and nutrient delivery along the western Antarctic Peninsula(2017) Corbett, D. Reide (David Reide), 1971-; Crenshaw, Jared; Null, Kimberly; Peterson, Richard N.; Peterson, Leigha E.; Lyons, W. BerryThe surface waters of the Southern Ocean play a key role in the global climate and carbon cycles by promoting growth of some of the world’s largest phytoplankton blooms. Several studies have emphasized the importance of glacial and sediment inputs of Fe that fuel the primary production of the Fe-limited Southern Ocean. Although the fertile surface waters along the shelf of the western Antarctic Peninsula (WAP) are influenced by large inputs of freshwater, this freshwater may take multiple pathways (e.g. calving, streams, groundwater discharge) with different degrees of water-rock interactions leading to variable Fe flux to coastal waters. During the summers of 2012–13 and 2013–14, seawater samples were collected along the WAP, near Anvers Island, to observe water column dynamics in nearshore and offshore waters. Tracers (223,224Ra, 222Rn, 18O, 2H) were used to evaluate the source and transport of water and nutrients in coastal fjords and across the shelf. Coastal waters are compared across two field seasons, with increased freshwater observed during 2014. Horizontal mixing rates of water masses along the WAP ranged from 110–3600 m2 s-1. These mixing rates suggest a rapid transport mechanism for moving meltwater offshore.Item Open Access Biophysical Mechanisms Mediating Fibrin Fiber Lysis(2017-05-28) Hudson, Nathan E.The formation and dissolution of blood clots is both a biochemical and a biomechanical process. While much of the chemistry has been worked out for both processes, the influence of biophysical properties is less well understood. This review considers the impact of several structural and mechanical parameters on lytic rates of fibrin fibers. The influences of fiber and network architecture, fiber strain, FXIIIa cross-linking, and particle transport phenomena will be assessed. The importance of the mechanical aspects of fibrinolysis is emphasized, and future research avenues are discussed.Item Open Access Resolving power of diffraction imaging with an objective: a numerical study(2017-05) Wang, Wenjin; Liu, Jing; Lu, Jun Q.; Ding, Junhua; Hu, Xin-HuaDiffraction imaging in the far-field can detect 3D morphological features of an object for its coherent nature. We describe methods for accurate calculation and analysis of diffraction images of scatterers of single and double spheres by an imaging unit based on microscope objective at non-conjugate positions. A quantitative study of the calculated diffraction imaging in spectral domain has been performed to assess the resolving power of diffraction imaging. It has been shown numerically that with coherent illumination of 532 nm in wavelength the imaging unit can resolve single spheres of 2 μm or larger in diameters and double spheres separated by less than 300 nm between their centers.Item Open Access The effects of elevated temperature and dissolved ρCO2 on a marine foundation species(2017-04) Speights, Cori J.; Silliman, Brian R.; McCoy, Michael W.Understanding how climate change and other environmental stressors will affect species is a fundamental concern of modern ecology. Indeed, numerous studies have documented how climate stressors affect species distributions and population persistence. However, relatively few studies have investigated how multiple climate stressors might affect species. In this study, we investigate the impacts of how two climate change factors affect an important foundation species. Specifically, we tested how ocean acidification from dissolution of CO2 and increased sea surface temperatures affect multiple characteristics of juvenile eastern oysters (Crassostrea virginica). We found strong impacts of each stressor, but no interaction between the two. Simulated warming to mimic heat stressed summers reduced oyster growth, survival, and filtration rates. Additionally, we found that CO2-induced acidification reduced strength of oyster shells, which could potentially facilitate crab predation. As past studies have detected few impacts of these stressors on adult oysters, these results indicate that early life stages of calcareous marine organisms may be more susceptible to effects of ocean acidification and global warming. Overall, these data show that predicted changes in temperature and CO2 can differentially influence direct effects on individual species, which could have important implications for the nature of their trophic interactions.Item Open Access Health effects following subacute exposure to geogenic dust collected from active drainage surfaces (Nellis Dunes Recreation Area, Las Vegas, NV)(2017-12-08) DeWitt, Jamie C.; Buck, Brenda J.; Goossens, Dirk; Teng, Yuanxin; Pollard, James; McLaurin, Brett T.; Gerads, Russell; Keil, Deborah E.The specific health effects of directinhalation of fine minerogenic dusts generated by natural soil surfaces remain poorly known and relatively little researched. To learn more about this exposure and its contribution to human health effects, we surveyed surface sediment and characterized dust from the Nellis Dunes Recreation Area (NDRA) in Clark County, Nevada, a popular off-road vehicle (ORV) recreational site. Dry drainage systems at NDRA are commonly used as natural trail systems for ORV recreation; these surfaces also are characterized by high concentrations of heavy metals. Geogenic dust with a median diameter of 4.05 m, collected from drainage surfaces at NDRA contained a total elemental concentration of aluminum (79,651 g/g), vanadium (100 g/g), chromium (54 g/g), manganese (753 g/g), iron (33,266 g/g), cobalt(14 g/g), copper (37 g/g) zinc (135 g/g), arsenic (71 g/g), strontium (666 g/g), cesium (15 g/g), lead (34 g/g), and uranium (54.9 g/g).Adultfemale B6C3F1 mice exposed via oropharyngeal aspiration to 0.01–100 mg dust/kg body weight, four times, a week apart, for 28-days, were evaluated for immuno- and neurotoxicological outcomes 24 h after the last exposure. Antigen-specific IgM responses were dose-responsively suppressed at 0.1, 1.0, 10 and 100 mg/kg. Splenic lymphocytic subpopulations, hematological and clinical chemistry parameters were affected. In brain tissue, antibodies against NF-68, and GFAP were not affected, whereas IgM antibodies against MBP were reduced by 26.6% only in the highest dose group. A lowest observed adverse effect level (LOAEL) of 0.1 mg/kg/day and a no observed adverse effect level (NOAEL) of 0.01 mg/kg/day were derived based on the antigen primary IgM responses after subacute exposure to this geogenic dust.Item Open Access A 14-year longitudinal study of the impact of clean indoor air legislation on state smoking prevalence, USA, 1997-2010(2017) Becker, Craig M.; Lee, Joseph G. L.; Hudson, Suzanne; Hoover, Jeanne K.; Civils, DonaldWhile clean indoor air legislation at the state level is an evidence-based recommendation, only limited evidence exists regarding the impact of clean indoor air policies on state smoking prevalence. Using state smoking prevalence data from 1997 to 2010, a repeated measures observational analysis assessed the association between clean indoor air policies (i.e., workplace, restaurant, and bar) and state smoking prevalence while controlling for state cigarette taxes and year. The impacts from the number of previous years with any clean indoor air policy, the number of policies newly in effect during the current year, and the number of policies in effect the previous year were analyzed. Findings indicate a smoking prevalence predicted decrease of 0.13 percentage points (p = 0.03) for each additional year one or more clean indoor air policies were in effect, a predicted decrease of 0.12 percentage points (p = 0.09) for each policy newly in effect in the current year, and a predicted decrease of 0.22 percentage points (p = 0.01) for each policy in effect in the previous year on the subsequent year. Clean indoor air policies show measurable associations with reductions in smoking prevalence within a year of implementation above and beyond taxes and time trends. Further efforts are needed to diffuse clean indoor air policies across states and provinces that have not yet adopted such policies.Item Open Access A possible dose–response association between distance to farmers’ markets and roadside produce stands, frequency of shopping, fruit and vegetable consumption, and body mass index among customers in the Southern United States(2017-01) Jilcott Pitts, Stephanie Bell; Hinkley, Jedediah; Wu, Qiang; McGuirt, Jared T.; Lyonnais, Mary Jane; Rafferty, Ann P.; Whitt, Olivia R.; Winterbauer, Nancy L.; Phillips, LisaBackground: The association between farmers’ market characteristics and consumer shopping habits remains unclear. Our objective was to examine associations among distance to farmers’ markets, amenities within farmers’ markets, frequency of farmers’ market shopping, fruit and vegetable consumption, and body mass index (BMI). We hypothesized that the relationship between frequency of farmers’ market shopping and BMI would be mediated by fruit and vegetable consumption. Methods: In 15 farmers’ markets in northeastern North Carolina, July–September 2015, we conducted a crosssectional survey among 263 farmers’ market customers (199 provided complete address data) and conducted farmers’ market audits. To participate, customers had to be over 18 years of age, and English speaking. Dependent variables included farmers’ market shopping frequency, fruit and vegetable consumption, and BMI. Analysis of variance, adjusted multinomial logistic regression, Poisson regression, and linear regression models, adjusted for age, race, sex, and education, were used to examine associations between distance to farmers’ markets, amenities within farmers’ markets, frequency of farmers’ market shopping, fruit and vegetable consumption, and BMI. Results: Those who reported shopping at farmers’ markets a few times per year or less reported consuming 4.4 (standard deviation = 1.7) daily servings of fruits and vegetables, and those who reported shopping 2 or more times per week reported consuming 5.5 (2.2) daily servings. There was no association between farmers’ market amenities, and shopping frequency or fruit and vegetable consumption. Those who shopped 2 or more times per week had a statistically significantly lower BMI than those who shopped less frequently. There was no evidence of mediation of the relationship between frequency of shopping and BMI by fruit and vegetable consumption. Conclusions: More work should be done to understand factors within farmers’ markets that encourage fruit and vegetable purchases.Item Open Access Applying Community-Based Participatory Research Partnership Principles to Public Health Practice-Based Research Networks(2016) Winterbauer, Nancy L.; Bekemeier, Betty; VanRaemdonck, Lisa; Hoover, Anna G.With real-world relevance and translatability as important goals, applied methodological approaches have arisen along the participatory continuum that value context and empower stakeholders to partner actively with academics throughout the research process. Community-based participatory research (CBPR) provides the gold standard for equitable, partnered research in traditional communities. Practice-based research networks (PBRNs) also have developed, coalescing communities of practice and of academics to identify, study, and answer practice-relevant questions. To optimize PBRN potential for expanding scientific knowledge, while bridging divides across knowledge production, dissemination, and implementation, we elucidate how PBRN partnerships can be strengthened by applying CBPR principles to build and maintain research collaboratives that empower practice partners. Examining the applicability of CBPR partnership principles to public health (PH) PBRNs, we conclude that PH-PBRNs can serve as authentic, sustainable CBPR partnerships, ensuring the co-production of new knowledge, while also improving and expanding the implementation and impact of research findings in real-world settings.Item Open Access The Short-Term Effect of Weight Loss Surgery on Volumetric Breast Density and Fibroglandular Volume(2016-10-26) Vohra, Nasreen A.; Kachare, Swapnil D.; Vos, Paul; Schroeder, Bruce F.; Schuth, Olga; Suttle, Dylan; Fitzgerald, Timothy L.; Wong, Jan H.; Verbanac, Kathryn M.Purpose: Obesity and breast density are both associated with an increased risk of breast cancer and are potentially modifiable. Weight loss surgery (WLS) causes a significant reduction in the amount of body fat and a decrease in breast cancer risk. The effect of WLS on breast density and its components has not been documented. Here, we analyze the impact of WLS on volumetric breast density (VBD) and on each of its components (fibroglandular volume and breast volume) by using three-dimensional methods. Materials and Methods: Fibroglandular volume, breast volume, and their ratio, the VBD, were calculated from mammograms before and after WLS by using Volpara™ automated software. Results: For the 80 women included, average body mass index decreased from 46.0 ± 7.22 to 33.7 ± 7.06 kg/m2. Mammograms were performed on average 11.6 ± 9.4 months before and 10.1 ± 7 months after WLS. There was a significant reduction in average breast volume (39.4 % decrease) and average fibroglandular volume (15.5 % decrease), and thus, the average VBD increased from 5.15 to 7.87 % (p < 1 × 10−9) after WLS. When stratified by menopausal status and diabetic status, VBD increased significantly in all groups but only perimenopausal and postmenopausal women and non-diabetics experienced a significant reduction in fibroglandular volume. Conclusions: Breast volume and fibroglandular volume decreased, and VBD increased following WLS, with the most significant change observed in postmenopausal women and non-diabetics. Further studies are warranted to determine how physical and biological alterations in breast density components after WLS may impact breast cancer risk.Item Open Access Does Land Degradation Increase Poverty in Developing Countries?(2016-05-11) Barbier, Edward B.; Hochard, Jacob P.Land degradation is a global problem that particularly impacts the poor rural inhabitants of low and middle-income countries. We improve upon existing literature by estimating the extent of rural populations in 2000 and 2010 globally on degrading and improving agricultural land, taking into account the role of market access, and analyzing the resulting impacts on poverty. Using a variety of spatially referenced datasets, we estimate that 1.33 billion people worldwide in 2000 were located on degrading agricultural land (DAL), of which 1.26 billion were in developing countries. Almost all the world’s 200 million people on remote DAL were in developing countries, which is about 6% of their rural population. There were also 1.54 billion rural people on improving agricultural land (IAL), with 1.34 billion in developing countries. We find that a lower share of people in 2000 on DAL, or a higher share on IAL, lowers significantly how much overall economic growth reduces poverty from 2000 to 2012 across 83 developing countries. As the population on DAL and IAL in developing countries grew by 13% and 15% respectively from 2000 to 2010, these changing spatial distributions of rural populations could impact significantly future poverty in developing countries.Item Open Access The mismatch between current statistical practice and doctoral training in ecology(2016-08-17) Touchon, Justin C.; McCoy, Michael W.Ecologists are studying increasingly complex and important issues such as climate change and ecosystem services. These topics often involve large data sets and the application of complicated quantitative models. We evaluated changes in statistics used by ecologists by searching nearly 20,000 published articles in ecology from 1990 to 2013. We found that there has been a rise in sophisticated and computationally intensive statistical techniques such as mixed effects models and Bayesian statistics and a decline in reliance on approaches such as ANOVA or t tests. Similarly, ecologists have shifted away from software such as SAS and SPSS to the open source program R. We also searched the published curricula and syllabi of 154 doctoral programs in the United States and found that despite obvious changes in the statistical practices of ecologists, more than one-third of doctoral programs showed no record of required or optional statistics classes. Approximately one-quarter of programs did require a statistics course, but most of those did not cover contemporary statistical philosophy or advanced techniques. Only one-third of doctoral programs surveyed even listed an optional course that teaches some aspect of contemporary statistics. We call for graduate programs to lead the charge in improving training of future ecologists with skills needed to address and understand the ecological challenges facing humanity.Item Open Access A Genetic Mosaic Screen Reveals Ecdysone-Responsive Genes Regulating Drosophila Oogenesis(2016-08) Ables, Elizabeth Tweedie; Hwang, Grace H.; Finger, Danielle S.; Hinnant, Taylor D.; Drummond-Barbosa, DanielaMultiple aspects of Drosophila oogenesis, including germline stem cell activity, germ cell differentiation, and follicle survival, are regulated by the steroid hormone ecdysone. While the transcriptional targets of ecdysone signaling during development have been studied extensively, targets in the ovary remain largely unknown. Early studies of salivary gland polytene chromosomes led to a model in which ecdysone stimulates a hierarchical transcriptional cascade, wherein a core group of ecdysone-sensitive transcription factors induce tissue-specific responses by activating secondary branches of transcriptional targets. More recently, genome-wide approaches have identified hundreds of putative ecdysone-responsive targets. Determining whether these putative targets represent bona fide targets in vivo, however, requires that they be tested via traditional mutant analysis in a cell-type specific fashion. To investigate the molecular mechanisms whereby ecdysone signaling regulates oogenesis, we used genetic mosaic analysis to screen putative ecdysone-responsive genes for novel roles in the control of the earliest steps of oogenesis. We identified a cohort of genes required for stem cell maintenance, stem and progenitor cell proliferation, and follicle encapsulation, growth, and survival. These genes encode transcription factors, chromatin modulators, and factors required for RNA transport, stability, and ribosome biogenesis, suggesting that ecdysone might control a wide range of molecular processes during oogenesis. Our results suggest that, although ecdysone target genes are known to have cell type-specific roles, many ecdysone response genes that control larval or pupal cell types at developmental transitions are used reiteratively in the adult ovary. These results provide novel insights into the molecular mechanisms by which ecdysone signaling controls oogenesis, laying new ground for future studies.Item Open Access Author Impact Measures in Communication Sciences and Disorders(2015-11-13) Thomas, William Joseph; Stuart, Andrew; Faucette, Sarah P.Author impact metrics were collected from approximately 2000 academic research faculty in 257 accredited universities in the US and Canada. Three databases (Scopus, Google Scholar, and ResearchGate) were utilized. Indices (e.g., publications, citations, and h-index) were examined as a function of gender, rank, area of study, region, and Carnegie Classification.