• Gaps, Inexperience, Inconsistencies, and Overlaps: Crisis in the Regulation of Genetically Modified Plants and Animals

      Mandel, Gregory N. (2004)
      The regulation of genetically modified products pursuant to statutes enacted decades prior to the advent of biotechnology has created a regulatory system that is passive rather than proactive about risks, has difficulty adapting to biotechnology advances, and is highly fractured and inefficient-transgenic plants and animals are governed by at least twelve different statutes and five different agencies or services. The deficiencies resulting from this piecemeal approach to regulation unnecessarily expose society and the environment to adverse risks of biotechnology and introduce numerous inefficiencies into the regulatory system. These risks and inefficiencies include gaps in regulation, duplicative and inconsistent regulation, unnecessary regulatory expense, agencies acting outside their areas of expertise, and unnecessary increases in the cost of and delay in the development and commercialization of new biotechnology products. These deficiencies also increase the risk of further unnecessary biotechnology scares, which may cause public overreaction against biotechnology products, preventing the maximization of social welfare. With science and society poised to soar from first-generation biotechnology (focused on crops modified for agricultural benefit), to next-generation developments (including transgenic fish, insects, and livestock, and pharmaceutical-producing and industrial compound-producing plants and animals), it is necessary to establish a comprehensive, efficient, and scientifically rigorous regulatory system. This Article details how to achieve such a result through fixing the deficiencies in, and risks created by, the current regulatory structure. Ignoring many details, the solutions can be summarized in two categories. First, statutory and regulatory gaps that are identified must be closed with new legislation and regulation. Second, regulation of genetically modified products must be shifted from a haphazard model based on statutes not intended to cover biotechnology to a system based upon agency expertise in handling particular types of risks.
    • Gene expression signatures can aid diagnosis of sexually transmitted infection-induced endometritis in women

      Zheng, X; O'Connell, CM; Zhong, W; Poston, TB; Wiesenfeld, HC; Hillier, SL; Trent, M; Gaydos, C; Tseng, G; Taylor, BD; Darville, T; Taylor, Brandie|0000-0002-8234-1815 (2018-09-20)
      © 2007 - 2018 Frontiers Media S.A. All Rights Reserved. Sexually transmitted infection (STI) of the upper reproductive tract can result in inflammation and infertility. A biomarker of STI-induced upper tract inflammation would be significant as many women are asymptomatic and delayed treatment increases risk of sequelae. Blood mRNA from 111 women from three cohorts was profiled using microarray. Unsupervised analysis revealed a transcriptional profile that distinguished 9 cases of STI-induced endometritis from 18 with cervical STI or uninfected controls. Using a hybrid feature selection algorithm we identified 21 genes that yielded maximal classification accuracy within our training dataset. Predictive accuracy was evaluated using an independent testing dataset of 5 cases and 10 controls. Sensitivity was evaluated in a separate test set of 12 women with asymptomatic STI-induced endometritis in whom cervical burden was determined by PCR; and specificity in an additional test set of 15 uninfected women with pelvic pain due to unknown cause. Disease module preservation was assessed in 42 women with a clinical diagnosis of pelvic inflammatory disease (PID). We also tested the ability of the biomarker to discriminate STI-induced endometritis from other diseases. The biomarker was 86.7% (13/15) accurate in correctly distinguishing cases from controls in the testing dataset. Sensitivity was 83.3% (5/6) in women with high cervical Chlamydia trachomatis burden and asymptomatic endometritis, but 0% (0/6) in women with low burden. Specificity in patients with non-STI-induced pelvic pain was 86.7% (13/15). Disease modules were preserved in all 8 biomarker predicted cases. The 21-gene biomarker was highly discriminatory for systemic infections, lupus, and appendicitis, but wrongly predicted tuberculosis as STI-induced endometritis in 52.4%. A 21-gene biomarker can identify asymptomatic women with STI-induced endometritis that places them at risk for chronic disease development and discriminate STI-induced endometritis from non-STI pelvic pain and other diseases.
    • General anesthetics predicted to block the GLIC pore with micromolar affinity

      LeBard, DN; Hénin, J; Eckenhoff, RG; Klein, ML; Brannigan, G (2012-05-01)
      Although general anesthetics are known to modulate the activity of ligand-gated ion channels in the Cys-loop superfamily, there is at present neither consensus on the underlying mechanisms, nor predictive models of this modulation. Viable models need to offer quantitative assessment of the relative importance of several identified anesthetic binding sites. However, to date, precise affinity data for individual sites has been challenging to obtain by biophysical means. Here, the likely role of pore block inhibition by the general anesthetics isoflurane and propofol of the prokaryotic pentameric channel GLIC is investigated by molecular simulations. Microscopic affinities are calculated for both single and double occupancy binding of isoflurane and propofol to the GLIC pore. Computations are carried out for an open-pore conformation in which the pore is restrained to crystallographic radius, and a closed-pore conformation that results from unrestrained molecular dynamics equilibration of the structure. The GLIC pore is predicted to be blocked at the micromolar concentrations for which inhibition by isofluorane and propofol is observed experimentally. Calculated affinities suggest that pore block by propofol occurs at signifcantly lower concentrations than those for which inhibition is observed: we argue that this discrepancy may result from binding of propofol to an allosteric site recently identified by X-ray crystallography, which may cause a competing gain-of-function effect. Affinities of isoflurane and propofol to the allosteric site are also calculated, and shown to be 3 mM for isoflurane and 10μM for propofol; both anesthetics have a lower affinity for the allosteric site than for the unoccupied pore. © 2012 LeBard et al.
    • General parenting styles and children's obesity risk: Changing focus

      Larsen, JK; Sleddens, EFC; Vink, JM; Fisher, JO; Kremers, SPJ (2018-11-06)
    • Generalized TMDs and the exclusive double Drell–Yan process

      Bhattacharya, S; Metz, A; Zhou, J (2017-08-01)
      © 2017 The Authors Generalized transverse momentum dependent parton distributions (GTMDs) are the most general parton correlation functions of hadrons. By considering the exclusive double Drell–Yan process it is shown for the first time how quark GTMDs can be measured. Specific GTMDs can be addressed by means of polarization observables.
    • Generation, Resuspension, and Transport of Particulate Matter From Biochar-Amended Soils: A Potential Health Risk

      Ravi, S; Li, J; Meng, Z; Zhang, J; Mohanty, S; Ravi, Sujith|0000-0002-0425-9373 (2020-11-01)
      ©2020. The Authors. Large-scale soil application of biochar is one of the terrestrial carbon sequestration strategies for future climate change mitigation pathways, which can also help remove and sequester pollutants from contaminated soil and water. However, black carbon emissions from biochar-amended soils can deteriorate air quality and affect human health, as the biochar particles often contain a higher amount of sorbed toxic pollutants than the soil. Yet, the extent and mechanism of inhalable particulate matter (PM10) emission from biochar-amended soils at different wind regimes have not been evaluated. Using wind tunnel experiments to simulate different wind regimes, we quantified particulate emission from sand amended with 1–4% (by weight) biochar at two size fractions: with and without <2-mm biochar. At wind speeds below the threshold speed for soil erosion, biochar application significantly increased PM10 emission by up to 400% due to the direct resuspension of inhalable biochar particles. At wind speeds above the threshold speed, emission increased by up to 300% even from biochar without inhalable fractions due to collisions of fast-moving sand particles with large biochar particles. Using a theoretical framework, we show that particulate matter emissions from biochar-amended soils could be higher than that previously expected at wind speeds below the erosion threshold wind speed for background soil. Our results indicate that current models for fugitive dust emissions may underestimate the particulate matter emission potential of biochar-amended soils and will help improve the assessment of biochar emission from amended soils.
    • Genetic diversity and population structure of genes encoding vaccine candidate antigens of Plasmodium vivax

      Chenet, SM; Tapia, LL; Escalante, AA; Durand, S; Lucas, C; Bacon, DJ (2012-03-15)
      Background: A major concern in malaria vaccine development is genetic polymorphisms typically observed among Plasmodium isolates in different geographical areas across the world. Highly polymorphic regions have been observed in Plasmodium falciparum and Plasmodium vivax antigenic surface proteins such as Circumsporozoite protein (CSP), Duffy-binding protein (DBP), Merozoite surface protein-1 (MSP-1), Apical membrane antigen-1 (AMA-1) and Thrombospondin related anonymous protein (TRAP). Methods. Genetic variability was assessed in important polymorphic regions of various vaccine candidate antigens in P. vivax among 106 isolates from the Amazon Region of Loreto, Peru. In addition, genetic diversity determined in Peruvian isolates was compared to population studies from various geographical locations worldwide. Results: The structured diversity found in P. vivax populations did not show a geographic pattern and haplotypes from all gene candidates were distributed worldwide. In addition, evidence of balancing selection was found in polymorphic regions of the trap, dbp and ama-1 genes. Conclusions: It is important to have a good representation of the haplotypes circulating worldwide when implementing a vaccine, regardless of the geographic region of deployment since selective pressure plays an important role in structuring antigen diversity. © 2012 Chenet et al; licensee BioMed Central Ltd.
    • Genetic diversity of vaccine candidate antigens in Plasmodium falciparum isolates from the Amazon basin of Peru

      Chenet, SM; Branch, OLH; Escalante, AA; Lucas, CM; Bacon, DJ (2008-06-26)
      Background. Several of the intended Plasmodium falciparum vaccine candidate antigens are highly polymorphic and could render a vaccine ineffective if their antigenic sites were not represented in the vaccine. In this study, characterization of genetic variability was performed in major B and T-cell epitopes within vaccine candidate antigens in isolates of P. falciparum from Peru. Methods. DNA sequencing analysis was completed on 139 isolates of P. falciparum collected from endemic areas of the Amazon basin in Loreto, Peru from years 1998 to 2006. Genetic diversity was determined in immunological important regions in circumsporozoite protein (CSP), merozoite surface protein-1 (MSP-1), apical membrane antigen-1 (AMA-1), liver stage antigen-1 (LSA-1) and thrombospondin-related anonymous protein (TRAP). Alleles identified by DNA sequencing were aligned with the vaccine strain 3D7 and DNA polymorphism analysis and FST study-year pairwise comparisons were done using the DnaSP software. Multilocus analysis (MLA) was performed and average of expected heterozygosity was calculated for each loci and haplotype over time. Results. Three different alleles for CSP, seven for MSP-1 Block 2, one for MSP-1 Block 17, three for AMA-1 and for LSA-1 each and one for TRAP were identified. There were 24 different haplotypes in 125 infections with complete locus typing for each gene. Conclusion. Characterization of the genetic diversity in Plasmodium isolates from the Amazon Region of Peru showed that P. falciparum T and B cell epitopes in these antigens have polymorphisms more similar to India than to Africa. These findings are helpful in the formulation of a vaccine considering restricted repertoire populations. © 2008 Chenet et al; licensee BioMed Central Ltd.
    • Genetic effects on gene expression across human tissues

      Aguet, F; Brown, AA; Castel, SE; Davis, JR; He, Y; Jo, B; Mohammadi, P; Park, YS; Parsana, P; Segrè, AV; Strober, BJ; Zappala, Z; Cummings, BB; Gelfand, ET; Hadley, K; Huang, KH; Lek, M; Li, X; Nedzel, JL; Nguyen, DY; Noble, MS; Sullivan, TJ; Tukiainen, T; MacArthur, DG; Getz, G; Addington, A; Guan, P; Koester, S; Little, AR; Lockhart, NC; Moore, HM; Rao, A; Struewing, JP; Volpi, S; Brigham, LE; Hasz, R; Hunter, M; Johns, C; Johnson, M; Kopen, G; Leinweber, WF; Lonsdale, JT; McDonald, A; Mestichelli, B; Myer, K; Roe, B; Salvatore, M; Shad, S; Thomas, JA; Walters, G; Washington, M; Wheeler, J; Bridge, J; Foster, BA; Gillard, BM; Karasik, E; Kumar, R; Miklos, M; Moser, MT; Jewell, SD; Montroy, RG; Rohrer, DC; Valley, D; Mash, DC; Davis, DA; Sobin, L; Barcus, ME; Branton, PA; Abell, NS; Balliu, B; Delaneau, O; Frésard, L; Gamazon, ER; Garrido-Martín, D; Gewirtz, ADH; Gliner, G; Gloudemans, MJ; Han, B; He, AZ; Hormozdiari, F; Li, X; Liu, B; Kang, EY; McDowell, IC; Ongen, H; Palowitch, JJ; Peterson, CB; Quon, G; Ripke, S; Saha, A; Shabalin, AA; Shimko, TC; Sul, JH; Teran, NA; Tsang, EK; Zhang, H; Zhou, YH; Bustamante, CD; Cox, NJ; Guigó, R; Siminoff, Laura|0000-0002-6775-665X; Gardiner, Heather Marie|0000-0003-2017-991X (2017-10-11)
      © 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved. Characterization of the molecular function of the human genome and its variation across individuals is essential for identifying the cellular mechanisms that underlie human genetic traits and diseases. The Genotype-Tissue Expression (GTEx) project aims to characterize variation in gene expression levels across individuals and diverse tissues of the human body, many of which are not easily accessible. Here we describe genetic effects on gene expression levels across 44 human tissues. We find that local genetic variation affects gene expression levels for the majority of genes, and we further identify inter-chromosomal genetic effects for 93 genes and 112 loci. On the basis of the identified genetic effects, we characterize patterns of tissue specificity, compare local and distal effects, and evaluate the functional properties of the genetic effects. We also demonstrate that multi-tissue, multi-individual data can be used to identify genes and pathways affected by human disease-associated variation, enabling a mechanistic interpretation of gene regulation and the genetic basis of disease.
    • Genetic findings in sport-related concussions: potential for individualized medicine?

      McDevitt, Jane; Krynetskiy, Evgeny (2017-03)
      Concussion is a traumatic transient disturbance of the brain. In sport, the initial time and severity of concussion is known giving an opportunity for subsequent analysis. Variability in susceptibility and recovery between individual athletes depends, among other parameters, on genetic factors. The genes-encoding polypeptides that determine incidence, severity and prognosis for concussion are the primary candidates for genetic analysis. Genetic polymorphisms in the genes contributing to plasticity and repair (APOE), synaptic connectivity (GRIN2A), calcium influx (CACNA1E), uptake and deposit of glutamate (SLC17A7) are potential biomarkers of concussion incidence and recovery rate. With catalogued genetic variants, prospective genotyping of athletes at the beginning of their career will allow medical professionals to improve concussion management and return-to-play decisions.
    • Genome-Wide changes in genetic diversity in a population of myotis lucifugus affected by white-nose syndrome

      Lilley, TM; Wilson, IW; Field, KA; Reeder, DAM; Vodzak, ME; Turner, GG; Kurta, A; Blomberg, AS; Hoff, S; Herzog, CJ; Sewall, BJ; Paterson, S (2020-06-01)
      Copyright © 2020 Lilley et al. Novel pathogens can cause massive declines in populations, and even extirpation of hosts. But disease can also act as a selective pressure on survivors, driving the evolution of resistance or tolerance. Bat white-nose syndrome (WNS) is a rapidly spreading wildlife disease in North America. The fungus causing the disease invades skin tissues of hibernating bats, resulting in disruption of hibernation behavior, premature energy depletion, and subsequent death. We used whole-genome sequencing to investigate changes in allele frequencies within a population of Myotis lucifugus in eastern North America to search for genetic resistance to WNS. Our results show low FST values within the population across time, i.e., prior to WNS (Pre-WNS) compared to the population that has survived WNS (Post-WNS). However, when dividing the population with a geographical cut-off between the states of Pennsylvania and New York, a sharp increase in values on scaffold GL429776 is evident in the Post-WNS samples. Genes present in the diverged area are associated with thermoregulation and promotion of brown fat production. Thus, although WNS may not have subjected the entire M. lucifugus population to selective pressure, it may have selected for specific alleles in Pennsylvania through decreased gene flow within the population. However, the persistence of remnant sub-populations in the aftermath of WNS is likely due to multiple factors in bat life history.
    • Genome-wide influence of indel Substitutions on evolution of bacteria of the PVC superphylum, revealed using a novel computational method.

      Kamneva, OK; Liberles, DA; Ward, NL; Liberles, David A|0000-0003-3487-8826 (2010-01-01)
      Whole-genome scans for positive Darwinian selection are widely used to detect evolution of genome novelty. Most approaches are based on evaluation of nonsynonymous to synonymous substitution rate ratio across evolutionary lineages. These methods are sensitive to saturation of synonymous sites and thus cannot be used to study evolution of distantly related organisms. In contrast, indels occur less frequently than amino acid replacements, accumulate more slowly, and can be employed to characterize evolution of diverged organisms. As indels are also subject to the forces of natural selection, they can generate functional changes through positive selection. Here, we present a new computational approach to detect selective constraints on indel substitutions at the whole-genome level for distantly related organisms. Our method is based on ancestral sequence reconstruction, takes into account the varying susceptibility of different types of secondary structure to indels, and according to simulation studies is conservative. We applied this newly developed framework to characterize the evolution of organisms of the Planctomycetes, Verrucomicrobia, Chlamydiae (PVC) bacterial superphylum. The superphylum contains organisms with unique cell biology, physiology, and diverse lifestyles. It includes bacteria with simple cell organization and more complex eukaryote-like compartmentalization. Lifestyles range from free-living organisms to obligate pathogens. In this study, we conduct a whole-genome level analysis of indel substitutions specific to evolutionary lineages of the PVC superphylum and found that indels evolved under positive selection on up to 12% of gene tree branches. We also analyzed possible functional consequences for several case studies of predicted indel events.
    • Genomic analyses of African Trypanozoon strains to assess evolutionary relationships and identify markers for strain identification

      Richardson, JB; Lee, KY; Mireji, P; Enyaru, J; Sistrom, M; Aksoy, S; Zhao, H; Caccone, A (2017-09-29)
      © 2017 Richardson et al. African trypanosomes of the sub-genus Trypanozoon) are eukaryotic parasitesthat cause disease in either humans or livestock. The development of genomic resources can be of great use to those interested in studying and controlling the spread of these trypanosomes. Here we present a large comparative analysis of Trypanozoon whole genomes, 83 in total, including human and animal infective African trypanosomes: 21 T. brucei brucei, 22 T. b. gambiense, 35 T. b. rhodesiense and 4 T. evansi strains, of which 21 were from Uganda. We constructed a maximum likelihood phylogeny based on 162,210 single nucleotide polymorphisms (SNPs.) The three Trypanosoma brucei sub-species and Trypanosoma evansi are not monophyletic, confirming earlier studies that indicated high similarity among Trypanosoma “sub-species”. We also used discriminant analysis of principal components (DAPC) on the same set of SNPs, identifying seven genetic clusters. These clusters do not correspond well with existing taxonomic classifications, in agreement with the phylogenetic analysis. Geographic origin is reflected in both the phylogeny and clustering analysis. Finally, we used sparse linear discriminant analysis to rank SNPs by their informativeness in differentiating the strains in our data set. As few as 84 SNPs can completely distinguish the strains used in our study, and discriminant analysis was still able to detect genetic structure using as few as 10 SNPs. Our results reinforce earlier results of high genetic similarity between the African Trypanozoon. Despite this, a small subset of SNPs can be used to identify genetic markers that can be used for strain identification or other epidemiological investigations.
    • Genomic signatures of domestication on neurogenetic genes in Drosophila melanogaster

      Stanley, CE; Kulathinal, RJ; Kulathinal, Rob|0000-0003-1907-2744 (2016-01-05)
      © 2016 Stanley and Kulathinal. Background: Domesticated animals quickly evolve docile and submissive behaviors after isolation from their wild conspecifics. Model organisms reared for prolonged periods in the laboratory also exhibit similar shifts towards these domesticated behaviors. Yet whether this divergence is due to inadvertent selection in the lab or the fixation of deleterious mutations remains unknown. Results: Here, we compare the genomes of lab-reared and wild-caught Drosophila melanogaster to understand the genetic basis of these recently endowed behaviors common to laboratory models. From reassembled genomes of common lab strains, we identify unique, derived variants not present in global populations (lab-specific SNPs). Decreased selective constraints across low frequency SNPs (unique to one or two lab strains) are different from patterns found in the wild and more similar to neutral expectations, suggesting an overall accumulation of deleterious mutations. However, high-frequency lab SNPs found in most or all lab strains reveal an enrichment of X-linked loci and neuro-sensory genes across large extended haplotypes. Among shared polymorphisms, we also find highly differentiated SNPs, in which the derived allele is higher in frequency in the wild (Fstwild>lab), enriched for similar neurogenetic ontologies, indicative of relaxed selection on more active wild alleles in the lab. Conclusions: Among random mutations that continuously accumulate in the laboratory, we detect common adaptive signatures in domesticated lab strains of fruit flies. Our results demonstrate that lab animals can quickly evolve domesticated behaviors via unconscious selection by humans early on a broad pool of disproportionately large neurogenetic targets followed by the fixation of accumulated deleterious mutations on functionally similar targets.
    • Genomic timetree and historical biogeography of Caribbean island ameiva lizards (Pholidoscelis: Teiidae)

      Tucker, DB; Hedges, SB; Colli, GR; Pyron, RA; Sites, JW (2017-09-01)
      © 2017 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. The phylogenetic relationships and biogeographic history of Caribbean island ameivas (Pholidoscelis) are not well-known because of incomplete sampling, conflicting datasets, and poor support for many clades. Here, we use phylogenomic and mitochondrial DNA datasets to reconstruct a well-supported phylogeny and assess historical colonization patterns in the group. We obtained sequence data from 316 nuclear loci and one mitochondrial marker for 16 of 19 extant species of the Caribbean endemic genus Pholidoscelis. Phylogenetic analyses were carried out using both concatenation and species tree approaches. To estimate divergence times, we used fossil teiids to calibrate a timetree which was used to elucidate the historical biogeography of these lizards. All phylogenetic analyses recovered four well-supported species groups (clades) recognized previously and supported novel relationships of those groups, including a (P. auberi + P. lineolatus) clade (western + central Caribbean), and a (P. exsul + P. plei) clade (eastern Caribbean). Divergence between Pholidoscelis and its sister clade was estimated to have occurred ~25 Ma, with subsequent diversification on Caribbean islands occurring over the last 11 Myr. Of the six models compared in the biogeographic analyses, the scenario which considered the distance among islands and allowed dispersal in all directions best fit the data. These reconstructions suggest that the ancestor of this group colonized either Hispaniola or Puerto Rico from Middle America. We provide a well-supported phylogeny of Pholidoscelis with novel relationships not reported in previous studies that were based on significantly smaller datasets. We propose that Pholidoscelis colonized the eastern Greater Antilles from Middle America based on our biogeographic analysis, phylogeny, and divergence time estimates. The closing of the Central American Seaway and subsequent formation of the modern Atlantic meridional overturning circulation may have promoted dispersal in this group.
    • Geographic disparities in colorectal cancer survival

      Henry, KA; Niu, X; Boscoe, FP (2009-07-23)
      Background: Examining geographic variation in cancer patient survival can help identify important prognostic factors that are linked by geography and generate hypotheses about the underlying causes of survival disparities. In this study, we apply a recently developed spatial scan statistic method, designed for time-to-event data, to determine whether colorectal cancer (CRC) patient survival varies by place of residence after adjusting survival times for several prognostic factors. Methods: Using data from a population-based, statewide cancer registry, we examined a cohort of 25,040 men and women from New Jersey who were newly diagnosed with local or regional stage colorectal cancer from 1996 through 2003 and followed to the end of 2006. Survival times were adjusted for significant prognostic factors (sex, age, stage at diagnosis, race/ethnicity and census tract socioeconomic deprivation) and evaluated using a spatial scan statistic to identify places where CRC survival was significantly longer or shorter than the statewide experience. Results: Age, sex and stage adjusted survival times revealed several areas in the northern part of the state where CRC survival was significantly different than expected. The shortest and longest survival areas had an adjusted 5-year survival rate of 73.1% (95% CI 71.5, 74.9) and 88.3% (95% CI 85.4, 91.3) respectively, compared with the state average of 80.0% (95% CI 79.4, 80.5). Analysis of survival times adjusted for age, sex and stage as well as race/ethnicity and area socioeconomic deprivation attenuated the risk of death from CRC in several areas, but survival disparities persisted. Conclusion: The results suggest that in areas where additional adjustments for race/ethnicity and area socioeconomic deprivation changed the geographic survival patterns and reduced the risk of death from CRC, the adjustment factors may be contributing causes of the disparities. Further studies should focus on specific and modifiable individual and neighborhood factors in the high risk areas that may affect a person's chance of surviving cancer. © 2009 Henry et al; licensee BioMed Central Ltd.
    • Geographic Imputation of Missing Activity Space Data from Ecological Momentary Assessment (EMA) GPS Positions

      Mennis, Jeremy; Mason, Michael J.; Coffman, Donna L.; Henry, Kevin; 0000-0001-6319-8622; 0000-0002-5348-9669 (2018-12-04)
      This research presents a pilot study to develop and compare methods of geographic imputation for estimating the location of missing activity space data collected using geographic ecological momentary assessment (GEMA). As a demonstration, we use data from a previously published analysis of the effect of neighborhood disadvantage, captured at the U.S. Census Bureau tract level, on momentary psychological stress among a sample of 137 urban adolescents. We investigate the impact of listwise deletion on model results and test two geographic imputation techniques adapted for activity space data from hot deck and centroid imputation approaches. Our results indicate that listwise deletion can bias estimates of place effects on health, and that these impacts are mitigated by the use of geographic imputation, particularly regarding inflation of the standard errors. These geographic imputation techniques may be extended in future research by incorporating approaches from the non-spatial imputation literature as well as from conventional geographic imputation and spatial interpolation research that focus on non-activity space data.
    • Geometric symmetry of dielectric antenna influencing light absorption in quantum-sized metal nanocrystals: A comparative study

      Dai, X; Rasamani, KD; Hall, G; Makrypodi, R; Sun, Y; Sun, Yugang|0000-0001-6351-6977 (2018-10-01)
      © 2018 Dai, Rasamani, Hall, Makrypodi and Sun. Silica nanoparticles, optically transparent in the visible spectral region, represent a class of dielectric antenna to tune the propagation and local field distribution of the visible light through surface scattering while the energy loss is minimized. The light scattering on the surface of silica nanoparticles include resonant scattering and random scattering that strongly depend on their geometry: spherical silica nanoparticles with the highest geometrical symmetry favors the light scattering resonances on the nanoparticle surfaces to promote resonant scattering while non-spherical silica nanoparticles mainly support random scattering. Both resonant scattering and random scattering of light on the silica nanoparticles are capable of enhancing the light absorption in quantum-sized metal nanocrystals attached to the surfaces of the silica nanoparticles. The contributions of resonant scattering and random scattering to the enhancement of light absorption have been compared and discussed. The understanding highlights the importance of the geometry of the silica nanoparticle antenna on the design and synthesis of composite materials for efficient light harvesting.
    • Getting everyone onboard: Framing collective goal progress broadens participation in collective marketing campaigns

      Kim, Y; Reeck, C; Reeck, Crystal|0000-0002-1540-5321 (2019-01-01)
      © 2019 Kim and Reeck. Collective marketing campaigns may feature goals that are not shared equally by all customers, such as a fundraiser for an environmental cause. For such campaigns, how can marketers encourage broad participation? The present research demonstrates that the framing of collective progress in such campaigns can broaden participation by highlighting the “large area” of progress toward the goal, emphasizing progress achieved for campaigns in their late stages and progress remaining in their early stages. We tested this large area hypothesis in the context of a waste reduction drive, examining the reactions of Democrats and Republicans who might be more or less inclined to support the drive respectively. Study 1 examined these processes when the drive was nearing completion, finding that an accumulating frame (focusing on progress achieved) increased motivation to participate for Republicans to levels comparable with Democrats. Study 2 evaluated these processes at earlier stages in the drive’s progress. In these circumstances, a remaining frame (focusing on contributions still needed) increased motivation to participate among Republicans to a similar level as Democrats. These findings indicate framings that highlight the large area in collective progress broaden participation in collective marketing campaigns, suggesting that marketers should highlight remaining contributions needed early on and accumulated contributions received later in collective marketing campaigns.