@article{burkholder_kinder_dickey_reed_arellano_james_mackenzie_allen_lindor_mathis_et al._2022, title={Classic indicators and diel dissolved oxygen versus trend analysis in assessing eutrophication of potable-water reservoirs}, volume={3}, ISSN={["1939-5582"]}, DOI={10.1002/eap.2541}, abstractNote={Abstract}, journal={ECOLOGICAL APPLICATIONS}, author={Burkholder, JoAnn M. and Kinder, Carol A. and Dickey, David A. and Reed, Robert E. and Arellano, Consuelo and James, Jennifer L. and Mackenzie, Linda M. and Allen, Elle H. and Lindor, Nicole L. and Mathis, Joshua G. and et al.}, year={2022}, month={Mar} }
 @article{morkoc_aguilos_noormets_minick_ile_dickey_hardesty_kerrigan_heitman_king_2022, title={Environmental and Plant-Derived Controls on the Seasonality and Partitioning of Soil Respiration in an American Sycamore (Platanus occidentalis) Bioenergy Plantation Grown at Different Planting Densities}, volume={13}, ISSN={1999-4907}, url={http://dx.doi.org/10.3390/f13081286}, DOI={10.3390/f13081286}, abstractNote={Bioenergy is one of the most considered alternatives to fossil fuels. Short-rotation woody crops (SRWCs) as bioenergy sources are capable of alleviating energy constraints and sequestering atmospheric CO2. However, studies investigating soil carbon (C) dynamics at SWRC plantations are scarce. We studied American sycamore (Platanus occidentalis) as a model tree species for SRWC at different planting densities ((1) 0.5 × 2.0 m (10,000 trees·ha−1 or tph), (2) 1.0 × 2.0 m (5000 tph), and (3) 2.0 × 2.0 m (2500 tph)) to examine seasonal variation in total soil respiration (Rtotal), partitioned into heterotrophic (Rh) and autotrophic (Ra) respiration, and we evaluated climatic and biological controls on soil respiration. Rtotal and Rh exhibited larger seasonal variation than Ra (p < 0.05). During the nongrowing seasons, the average Rtotal was 0.60 ± 0.21 g·C·m−2·day−1 in winter and 1.41 ± 0.73 g·C·m−2·day−1 in fall. During the growing season, Rtotal was 2–7 times higher in spring (3.49 ± 1.44 g·C·m−2·day−1) and summer (4.01 ± 1.17 g·C·m−2·day−1) than winter. Average Rtotal was 2.30 ± 0.63 g·C·m−2·day−1 in 2500 tph, 2.43 ± 0.64 g·C·m−2·day−1 in 5000 tph, and 2.41 ± 0.75 g·C·m−2·day−1 in 10,000 tph treatments. Average Rh was 1.72 ± 0.40 g·C·m−2·day−1 in 2500 tph, 1.57 ± 0.39 g·C·m−2·day−1 in 5000 tph, and 1.93 ± 0.64 g·C·m−2·day−1 in 10,000 tph, whereas Ra had the lowest rates, with 0.59 ± 0.53 g·C·m−2·day−1 in 2500 tph, 0.86 ± 0.51 g·C·m−2·d−1 in 5000 tph, and 0.48 ± 0.34 g·C·m−2·day−1 in 10,000 tph treatments. Rh had a greater contribution to Rtotal (63%–80%) compared to Ra (20%–37%). Soil temperature was highly correlated to Rtotal (R2 = 0.92) and Rh (R2 = 0.77), while the correlation to Ra was weak (R2 = 0.21). Rtotal, Rh, and Ra significantly declined with soil water content extremes (e.g., <20% or >50%). Total root biomass in winter (469 ± 127 g·C·m−2) was smaller than in summer (616 ± 161 g·C·m−2), and the relationship of total root biomass to Rtotal, Rh, and Ra was only significant during the growing seasons (R2 = 0.12 to 0.50). The litterfall in 5000 tph (121 ± 16 g DW·m−2) did not differ (p > 0.05) from the 2500 tph (108 ± 16 g DW·m−2) or 10,000 tph (132 ± 16 g DW·m−2) treatments. In no circumstances were Rtotal, Rh, and Ra significantly correlated with litterfall amount across planting densities and seasons (p > 0.05). Overall, our results show that Rtotal in American sycamore SRWC is dominated by the heterotrophic component (Rh), is strongly correlated to soil environmental conditions, and can be minimized by planting at a certain tree density (5000 tph).}, number={8}, journal={Forests}, publisher={MDPI AG}, author={Morkoc, Suna and Aguilos, Maricar and Noormets, Asko and Minick, Kevan J. and Ile, Omoyemeh and Dickey, David A. and Hardesty, Deanna and Kerrigan, Maccoy and Heitman, Joshua and King, John}, year={2022}, month={Aug}, pages={1286} }
 @article{dickey_gonzalez-farias_muriel_2019, title={Asymptotic analysis of non-periodical cointegration with high seasonals}, volume={25}, ISSN={["2296-4495"]}, DOI={10.1007/s40590-018-0201-2}, number={2}, journal={BOLETIN DE LA SOCIEDAD MATEMATICA MEXICANA}, author={Dickey, David A. and Gonzalez-Farias, Graciela and Muriel, Nelson}, year={2019}, month={Jul}, pages={443–459} }
 @article{brown_bray_carlstead_dickey_farin_ange-van heugten_2019, title={Individual and environmental risk factors associated with fecal glucocorticoid metabolite concentrations in zoo-housed Asian and African elephants}, volume={14}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0217326}, abstractNote={A recent large-scale welfare study in North America involving 106 Asian (Elephas maximus) and 131 African (Loxodonta africana) elephants at 64 accredited facilities identified links (i.e., risk factors) between zoo environmental factors and a number of welfare outcomes (stereotypic behavior, ovarian acyclicity, hyperprolactinemia, walking and recumbence, body condition, health status, serum cortisol). For this population of elephants, we used the same epidemiological methods to examine associations between those risk factors and two additional welfare outcomes, mean concentration and individual variability (CV) of fecal glucocorticoid metabolite concentrations (FGM) as indicators of stress. Results indicate that African elephants are more responsive to social stressors than Asians, and that poor joint health is a stress-related welfare problem for Asian, but not African elephants in the North American population. For both species, higher FGM concentrations were associated with zoos located at more northern latitudes, whereas lower FGM concentrations were associated with having free access to indoor/outdoor spaces, and spending more time in managed interactions with staff. Also important for captive management, elephants having diverse enrichment options and belonging to compatible social groups exhibited reduced intra-individual variability in FGM concentrations. Our findings show that aspects of the zoo environment can be potential sources of stress for captive elephants, and that there are management activities that may facilitate coping with zoo conditions. Given species differences in factors that affected FGM, targeted, species-specific management approaches likely are needed to ensure good welfare for all elephants.}, number={9}, journal={PLOS One}, publisher={Cold Spring Harbor Laboratory}, author={Brown, Janine L. and Bray, Jessica D. and Carlstead, Kathy and Dickey, David and Farin, Charlotte and Ange-van Heugten, Kimberly}, editor={Hillmann, EdnaEditor}, year={2019}, month={May}, pages={e0217326} }
 @article{eickholt_carter_taliercio_dickey_dean_delheimer_li_2019, title={Registration of USDA-Max x Soja Core Set-1: Recovering 99% of Wild Soybean Genome from PI 366122 in 17 Agronomic Interspecific Germplasm Lines}, volume={13}, ISSN={["1940-3496"]}, DOI={10.3198/jpr2017.09.0059crg}, abstractNote={USDA‐Max × Soja Core Set‐1 (USDA‐MxS‐CS1‐1 to USDA‐MxS‐CS1‐17 [Reg. No. GP‐417 to GP‐433, PI 689053 to PI 689069]) is a group of 17 interspecific breeding lines developed from the hybridization of lodging‐resistant soybean cultivar N7103 [Glycine max (L.) Merr.] with wild soybean plant introduction PI 366122 [G. soja Siebold & Zucc.]. These materials were released by the USDA‐ARS and the North Carolina Agricultural Research Service (March 2017) to expand the North American soybean breeding pool. The full‐sib breeding lines are 50% wild soybean by pedigree and developed through bulk breeding and pedigree selection. Marker analysis of 2455 well‐distributed polymorphic single‐nucleotide polymorphism loci revealed that individual breeding lines ranged from 21 to 40% alleles derived from wild soybean. Collectively, most of the wild soybean genome was transferred to the core set in that 5, 10, and 17 breeding lines captured 83, 98, and 99% of G. soja–derived polymorphic alleles. Physical linkage maps suggested that extensive recombination occurred between the G. max and G. soja genomes. The 17 breeding lines are well adapted to the southeastern United States, exhibited seed yield ranging from 75 to 97% of the domesticated parent, and are group VI or VII maturity. Some breeding lines displayed increased seed protein, oil, or methionine content, and all exhibited increased seed size as compared to the domesticated parent. The novel genetic diversity, positive agronomic performance, and improved seed composition of these lines suggest that they are valuable genetic resources for US soybean breeding.}, number={2}, journal={JOURNAL OF PLANT REGISTRATIONS}, author={Eickholt, David and Carter, Thomas E., Jr. and Taliercio, Earl and Dickey, David and Dean, Lisa O. and Delheimer, Jake and Li, Zenglu}, year={2019}, month={May}, pages={217–236} }
 @article{niedziela_depa_nelson_willits_peet_dickey_mingis_2018, title={Effects of Carbon Dioxide and Photosynthetic Photon Flux on Mineral Content in Chrysanthemum Allowing for Growth as a Covariate}, volume={53}, ISSN={["2327-9834"]}, DOI={10.21273/hortsci12425-17}, abstractNote={The effect of CO2 concentration (330 and 675 μL·L−1) and photosynthetic photon flux (PPF) (mean daily peaks of 550–1400 μmol·m−2·s−1) on total mineral contents in shoots was studied in chrysanthemum [Dendranthema ×grandiflorum (Ramat) Kitam ‘Fiesta’] during three times of the year. Growth (as measured by shoot dry weight) and shoot mineral contents (weight of nutrient per shoot) of hydroponically grown plants were analyzed after 5 weeks. There was a positive synergistic interaction of CO2 concentration and PPF on growth with the greatest growth at high PPF (1400 μmol·m−2·s−1) with high CO2 (675 μL·L−1). When growth was not used as a covariate in the statistical model, both CO2 concentration and PPF significantly affected the content of all eight nutrients. However, after growth was included as a covariate in the model, nutrients were classified into three categories based on whether CO2 concentration and PPF level were needed in addition to growth to predict shoot nutrient content. Neither CO2 concentration nor PPF level was needed for Mg, Fe, and Mn contents, whereas PPF level was needed for N, P, K, and Ca contents, and both CO2 concentration and PPF level were required for B content.}, number={1}, journal={HORTSCIENCE}, author={Niedziela, Carl E., Jr. and Depa, Mary A. and Nelson, Paul V. and Willits, Daniel H. and Peet, Mary M. and Dickey, David A. and Mingis, Nancy C.}, year={2018}, month={Jan}, pages={73–77} }
 @article{williams_wells_dickey_hu_maul_raskin_reberg-horton_mirsky_2018, title={Establishing the relationship of soil nitrogen immobilization to cereal rye residues in a mulched system}, volume={426}, ISSN={["1573-5036"]}, DOI={10.1007/s11104-018-3566-0}, abstractNote={Soil nitrogen (N) immobilization from cover crop residues may help suppress weeds. We established a gradient of cereal rye shoot biomass to determine the extent that soil N can be immobilized and its effect on redroot pigweed (Amaranthus retroflexus L.). A microplot study was conducted in no-till cereal rye (Secale cereale L.)—soybean (Glycine max L. (Merr.)) systems at two sites in eastern USA. Microplots received 0, 2000, 5000, 8000, 12,000 or 15,000 kg ha−1 of cereal rye shoot biomass, and were injected with two mg 15N kg−1 soil 5 cm below the soil surface. Pigweeds were sown and allowed to germinate. Maximum rates of cereal rye shoot decomposition were observed at ≥5000 kg ha−1. Although cereal rye shoot N declined, shoots became enriched with 15N, indicating fungal transfer of soil N to shoots. Soil inorganic N declined by an average of 5 kg N ha−1. Pigweed tissue N and biomass were reduced in the presence of cereal rye. The magnitude of pigweed N reduction was similar across all shoot application rates. We found weak evidence for a cereal rye shoot-based N immobilization mechanism of weed suppression. Our results indicate N immobilization may be primarily due to root residues.}, number={1-2}, journal={PLANT AND SOIL}, author={Williams, Alwyn and Wells, M. Scott and Dickey, David A. and Hu, Shuijin and Maul, Jude and Raskin, Daniel T. and Reberg-Horton, S. Chris and Mirsky, Steven B.}, year={2018}, month={May}, pages={95–107} }
 @article{zhang_truong_tanguay_reif_2017, title={A New Statistical Approach to Characterize Chemical-Elicited Behavioral Effects in High-Throughput Studies Using Zebrafish}, volume={12}, ISSN={["1932-6203"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85010006539&partnerID=MN8TOARS}, DOI={10.1371/journal.pone.0169408}, abstractNote={Zebrafish have become an important alternative model for characterizing chemical bioactivity, partly due to the efficiency at which systematic, high-dimensional data can be generated. However, these new data present analytical challenges associated with scale and diversity. We developed a novel, robust statistical approach to characterize chemical-elicited effects in behavioral data from high-throughput screening (HTS) of all 1,060 Toxicity Forecaster (ToxCast™) chemicals across 5 concentrations at 120 hours post-fertilization (hpf). Taking advantage of the immense scale of data for a global view, we show that this new approach reduces bias introduced by extreme values yet allows for diverse response patterns that confound the application of traditional statistics. We have also shown that, as a summary measure of response for local tests of chemical-associated behavioral effects, it achieves a significant reduction in coefficient of variation compared to many traditional statistical modeling methods. This effective increase in signal-to-noise ratio augments statistical power and is observed across experimental periods (light/dark conditions) that display varied distributional response patterns. Finally, we integrated results with data from concomitant developmental endpoint measurements to show that appropriate statistical handling of HTS behavioral data can add important biological context that informs mechanistic hypotheses.}, number={1}, journal={PLOS ONE}, author={Zhang, Guozhu and Truong, Lisa and Tanguay, Robert L. and Reif, David M.}, editor={Neuhauss, Stephan C.F.Editor}, year={2017}, month={Jan} }
 @article{waldeck_burkey_carter_dickey_song_taliercio_2017, title={RNA-Seq study reveals genetic responses of diverse wild soybean accessions to increased ozone levels}, volume={18}, ISSN={["1471-2164"]}, DOI={10.1186/s12864-017-3876-2}, abstractNote={Ozone is an air pollutant widely known to cause a decrease in productivity in many plant species, including soybean (Glycine max (L.) Merr). While the response of cultivated soybean to ozone has been studied, very little information is available regarding the ozone response of its wild relatives. Ozone-resistant wild soybean accessions were identified by measuring the response of a genetically diverse group of 66 wild soybean (Glycine soja Zucc. and Sieb.) accessions to elevated ozone levels. RNA-Seq analyses were performed on leaves of different ages from selected ozone-sensitive and ozone-resistant accessions that were subjected to treatment with an environmentally relevant level of ozone. Many more genes responded to elevated ozone in the two ozone-sensitive accessions than in the ozone-resistant accessions. Analyses of the ozone response genes indicated that leaves of different ages responded differently to ozone. Older leaves displayed a consistent reduction in expression of genes involved in photosynthesis in response to ozone, while changes in expression of defense genes dominated younger leaf tissue in response to ozone. As expected, there is a substantial difference between the response of ozone-sensitive and ozone-resistant accessions. Genes associated with photosystem 2 were substantially reduced in expression in response to ozone in the ozone-resistant accessions. A decrease in peptidase inhibitors was one of several responses specific to one of the ozone resistant accessions. The decrease in expression in genes associated with photosynthesis confirms that the photosynthetic apparatus may be an early casualty in response to moderate levels of ozone. A compromise of photosynthesis would substantially impact plant growth and seed production. However, the resistant accessions may preserve their photosynthetic apparatus in response to the ozone levels used in this study. Older leaf tissue of the ozone-resistant accessions showed a unique down-regulation of genes associated with endopeptidase inhibitor activity. This study demonstrates the existence of significant diversity in wild soybean for ozone response. Wild soybean accessions characterized in this study can be used by soybean breeders to enhance ozone tolerance of this important food crop.}, journal={BMC GENOMICS}, author={Waldeck, Nathan and Burkey, Kent and Carter, Thomas and Dickey, David and Song, Qijian and Taliercio, Earl}, year={2017}, month={Jun} }
 @article{yan_pietrafesa_dickey_gayes_bao_2015, title={Seasonal prediction of landfalling hurricanes along Eastern Seaboard of the United States}, volume={35}, ISSN={["1097-0088"]}, DOI={10.1002/joc.4163}, abstractNote={Statistical models for the seasonal prediction of hurricane strikes on the Eastern Seaboard of the United States (ESUS) are developed with the application of the statistical software (SAS) generalized linear model (GENMOD) to perform a Poisson regression linked by a logarithmic function. Preseason climatic/oceanic signals of the El Nino South Oscillation (ENSO), the Atlantic Meridional Mode (AMM), the Atlantic Multi‐decadal Oscillation (AMO), Sahel rainfall (20°–10°N, 20°W–10°E) and the North Atlantic sea surface temperature (SST) across a selected domain, all of which are closely associated with the dominant principal components of the North Atlantic Hurricane Track Density Function (HTDF), are applied as predictors.}, number={9}, journal={INTERNATIONAL JOURNAL OF CLIMATOLOGY}, author={Yan, T. and Pietrafesa, L. J. and Dickey, D. A. and Gayes, P. T. and Bao, S.}, year={2015}, month={Jul}, pages={2647–2653} }
 @article{barnes_nelson_whipker_dickey_hesterberg_shi_2014, title={Statistical model for describing macronutrient impacts on container substrate pH over time}, volume={49}, number={2}, journal={HortScience}, author={Barnes, J. and Nelson, P. and Whipker, B. E. and Dickey, D. A. and Hesterberg, D. and Shi, W.}, year={2014}, pages={207–214} }
 @article{yan_pietrafesa_bell_dickey_2013, title={On the inverse relationship between North American snow extent and North Atlantic hurricane activity}, volume={33}, ISSN={["1097-0088"]}, DOI={10.1002/joc.3485}, abstractNote={Abstract}, number={4}, journal={INTERNATIONAL JOURNAL OF CLIMATOLOGY}, author={Yan, T. and Pietrafesa, L. J. and Bell, G. D. and Dickey, D. A.}, year={2013}, month={Mar}, pages={992–1000} }
 @article{mosavi_dickey_seracino_rizkalla_2012, title={Identifying damage locations under ambient vibrations utilizing vector autoregressive models and Mahalanobis distances}, volume={26}, ISSN={["0888-3270"]}, DOI={10.1016/j.ymssp.2011.06.009}, abstractNote={This paper presents a study for identifying damage locations in an idealized steel bridge girder using the ambient vibration measurements. A sensitive damage feature is proposed in the context of statistical pattern recognition to address the damage detection problem. The study utilizes an experimental program that consists of a two-span continuous steel beam subjected to ambient vibrations. The vibration responses of the beam are measured along its length under simulated ambient vibrations and different healthy/damage conditions of the beam. The ambient vibration is simulated using a hydraulic actuator, and damages are induced by cutting portions of the flange at two locations. Multivariate vector autoregressive models were fitted to the vibration response time histories measured at the multiple sensor locations. A sensitive damage feature is proposed for identifying the damage location by applying Mahalanobis distances to the coefficients of the vector autoregressive models. A linear discriminant criterion was used to evaluate the amount of variations in the damage features obtained for different sensor locations with respect to the healthy condition of the beam. The analyses indicate that the highest variations in the damage features were coincident with the sensors closely located to the damages. The presented method showed a promising sensitivity to identify the damage location even when the induced damage was very small.}, journal={MECHANICAL SYSTEMS AND SIGNAL PROCESSING}, author={Mosavi, A. A. and Dickey, D. and Seracino, R. and Rizkalla, S.}, year={2012}, month={Jan}, pages={254–267} }
 @article{nelson_dickey_smith_2011, title={Estimating time series and cross section tourism demand models: Mainland United States to Hawaii data}, volume={32}, ISSN={["1879-3193"]}, DOI={10.1016/j.tourman.2009.10.005}, abstractNote={A study of factors affecting the number of visitors to Hawaii during the period 1993–2007 prompted by an observed waning of the U. S. mainland to Hawaii visitor market was conducted. Both time series and cross section analyses revealed that Log Gross State Product, Log Chained Airfare and Log Distance to Orlando, Florida were the most important predictor variables. A mixed model which modeled Log Chained Gross State Product, Log Chained Airfare, two recessions plus the September 11, 2001 effect in addition to other fixed effects and random state effects was used. Cross section (spatial) airfare elasticities on an annual basis were high and growing over time, but those estimated from the time series analysis (temporal) were much lower. Elasticities derived from Gross State Product were moderately high and very stable over time. To counteract the distance effect, stopovers in existing mainland resort cities when en route to Hawaii and other promotions to develop a stronger presence of a Hawaii image were recommended.}, number={1}, journal={TOURISM MANAGEMENT}, author={Nelson, Larry A. and Dickey, David A. and Smith, Joy M.}, year={2011}, month={Feb}, pages={28–38} }
 @article{place_reberg-horton_dickey_carter_2011, title={Identifying Soybean Traits of Interest for Weed Competition}, volume={51}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2010.11.0654}, abstractNote={ABSTRACT}, number={6}, journal={CROP SCIENCE}, publisher={Crop Science Society of America}, author={Place, George T. and Reberg-Horton, S. Chris and Dickey, David A. and Carter, Thomas E., Jr.}, year={2011}, month={Nov}, pages={2642–2654} }
 @article{dickey_zhang_2010, title={Seasonal unit root tests in long periodicity cases}, volume={39}, ISSN={["1226-3192"]}, DOI={10.1016/j.jkss.2010.02.006}, number={3}, journal={JOURNAL OF THE KOREAN STATISTICAL SOCIETY}, author={Dickey, David A. and Zhang, Ying}, year={2010}, month={Sep}, pages={271–279} }
 @inproceedings{mosavi_dickey_seracino_rizkalla_2010, title={Time-series models for identifying damage location in structural members subjected to ambient vibrations}, volume={7650}, booktitle={Health monitoring of structural and biological systems 2010, pts 1 and 2}, author={Mosavi, A. A. and Dickey, D. and Seracino, R. and Rizkalla, S. H.}, year={2010} }
 @article{taylor_miller_pietrafesa_dickey_ross_2010, title={Winter winds and river discharge determine juvenile southern flounder (Paralichthys lethostigma) recruitment and distribution in North Carolina estuaries}, volume={64}, ISSN={["1873-1414"]}, DOI={10.1016/j.seares.2009.09.006}, abstractNote={Retrospective analyses of a 23 year data set on abundance of Age 0 southern flounder in 105 estuarine nursery areas in the coastal region of North Carolina showed that discernible temporal and spatial patterns exist among clusters of stations. Furthermore, these patterns could be quantitatively related to certain meteorological and hydrological variables, namely winds from the east–southeast (E–SE) and from the north–northeast (N–NE) sectors and river runoff, which explained up to 83% of the interannual variability in numbers. We developed a regression model using recent catch data (1987–2002) and used the model to hindcast an earlier segment of the time series (1979–1986). The model was found to be quite robust, and could predict year class strength within 1 to 80% in the test set of data. We interpret these results to mean that hydrodynamic factors are principally responsible for the observed interannual recruitment variability in southern flounder in NC, since the interannual pattern in abundance of Age 0 fish persists for 2 more years of adult life. Finally, we discuss the implications of the variable spatial distribution patterns for estimates of year class strength from juvenile abundance data. It is possible that estimates of year class strength with a useful level of confidence could be obtained from meteorological data during the larval migration period.}, number={1-2}, journal={JOURNAL OF SEA RESEARCH}, author={Taylor, J. Christopher and Miller, John M. and Pietrafesa, Leonard J. and Dickey, David A. and Ross, Steve W.}, year={2010}, pages={15–25} }
 @article{pilar munoz_dickey_2009, title={Are electricity prices affected by the US dollar to Euro exchange rate? The Spanish case}, volume={31}, ISSN={["1873-6181"]}, DOI={10.1016/j.eneco.2009.05.011}, abstractNote={The objective of this paper is to investigate the relationships between Spanish electricity spot prices and the US dollar/Euro (USD/Euro) exchange rate during the period 2005–2007, taking into account the study of the association between dollar and oil prices, in order to better understand the evolution of the former over time. The first finding in this study is that Spanish electricity spots prices, the USD/Euro exchange rate and oil prices are cointegrated; therefore there is a long-run equilibrium relationship between the three variables. Short-run relationships have been detected between oil prices and Spanish electricity prices and USD/Euro exchange rate in the sense that Spanish electricity prices and USD/Euro exchange rate are affected by oil prices in the short run. There is a transmission of volatility between USD/Euro exchange rate and oil prices to Spanish electricity prices; so although Spanish electricity prices are not affected in level by the movements of USD/Euro exchange rate, they are in volatility. In this kind of scenario the conclusions confirm that for countries so dependent on external causes as Spain, one possible solution for guarantying the energy security would be the promotion of the renewable energies. Therefore we cannot ignore the impact in the internal expenses of the cost of installation and generation of green energies so there must be a balance between the increase in renewables and the reasonable market price of the electricity.}, number={6}, journal={ENERGY ECONOMICS}, author={Pilar Munoz, M. and Dickey, David A.}, year={2009}, month={Nov}, pages={857–866} }
 @article{xie_flippin_deighton_funk_dickey_buchwalter_2009, title={Mercury(II) Bioaccumulation and Antioxidant Physiology in Four Aquatic Insects}, volume={43}, ISSN={["1520-5851"]}, DOI={10.1021/es802323r}, abstractNote={We examined Hg(II) bioaccumulation and compartmentalization patterns in conjunction with antioxidant responses in four aquatic insect species: two caddisflies (Chimarra sp. and Hydropsyche betteni) and two mayflies (Maccaffertium modestum and Isonychia sp). Total antioxidant capabilities differed among unexposed larvae, with both caddisfly species exhibiting elevated antioxidant activities relative to the mayflies. We were able to account for these differences by examining the constitutive activities of catalase (CAT), glutathione peroxidase (GPx), glutathione S-transferase (GST), and superoxide dismutase (SOD), in the four species. We also examined levels of reduced and oxidized glutathione and cysteine in the insects. Glutathione peroxidase and SOD were the most responsive to Hg exposure, with GPx catalytic activity increasing between 50 and 310%. Superoxide dismutase activity decreased between 35 and 50%. This SOD suppression was shown to be dose-dependent in both caddisflies, butthe strength of this suppression did not appear to be related to rates of uptake. Surprisingly, little Hg (<10%) was found in the heat-stable cytosolic protein subcellular compartment in each of the four species, suggesting that Hg was not well detoxified. By combining bioaccumulation studies with other physiological measures, we can begin to better understand the consequences of trace metal pollutants in nature.}, number={3}, journal={ENVIRONMENTAL SCIENCE & TECHNOLOGY}, author={Xie, Lingtian and Flippin, Jennifer L. and Deighton, Nigel and Funk, David H. and Dickey, David A. and Buchwalter, David B.}, year={2009}, month={Feb}, pages={934–940} }
 @article{aneja_arya_rumsey_kim_bajwa_arkinson_semunegus_dickey_stefanski_todd_et al._2008, title={Characterizing ammonia emissions from swine farms in eastern North Carolina: Part 2 - Potential environmentally superior technologies for waste treatment}, volume={58}, ISSN={["2162-2906"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-53849100726&partnerID=MN8TOARS}, DOI={10.3155/1047-3289.58.9.1145}, abstractNote={Abstract The need for developing environmentally superior and sustainable solutions for managing the animal waste at commercial swine farms in eastern North Carolina has been recognized in recent years. Program OPEN (Odor, Pathogens, and Emissions of Nitrogen), funded by the North Carolina State University Animal and Poultry Waste Management Center (APWMC), was initiated and charged with the evaluation of potential environmentally superior technologies (ESTs) that have been developed and implemented at selected swine farms or facilities. The OPEN program has demonstrated the effectiveness of a new paradigm for policy-relevant environmental research related to North Carolina’s animal waste management programs. This new paradigm is based on a commitment to improve scientific understanding associated with a wide array of environmental issues (i.e., issues related to the movement of N from animal waste into air, water, and soil media; the transmission of odor and odorants; disease-transmitting vectors; and airborne pathogens). The primary focus of this paper is on emissions of ammonia (NH3) from some potential ESTs that were being evaluated at full-scale swine facilities. During 2-week-long periods in two different seasons (warm and cold), NH3 fluxes from water-holding structures and NH3 emissions from animal houses or barns were measured at six potential EST sites: (1) Barham farm—in-ground ambient temperature anaerobic digester/energy recovery/greenhouse vegetable production system; (2) BOC #93 farm—upflow biofiltration system—EKOKAN ; (3) Carrolls farm—aerobic blanket system—ISSUES-ABS; (4) Corbett #1 farm—solids separation/gasification for energy and ash recovery centralized system—BEST; (5) Corbett #2 farm—solid separation/reciprocating water technology—ReCip; and (6) Vestal farm—Recycling of Nutrient, Energy and Water System—ISSUES—RENEW. The ESTs were compared with similar measurements made at two conventional lagoon and spray technology (LST) farms (Moore farm and Stokes farm). A flow-through dynamic chamber system and two sets of open-path Fourier transform infrared (OP-FTIR) spectrometers measured NH3 fluxes continuously from water-holding structures and emissions from housing units at the EST and conventional LST sites. A statisticalobservational model for lagoon NH3 flux was developed using a multiple linear regression analysis of 15-min averaged NH3 flux data against the relevant environmental parameters measured at the two conventional farms during two different seasons of the year. This was used to compare the water-holding structures at ESTs with those from lagoons at conventional sites under similar environmental conditions. Percentage reductions in NH3 emissions from different components of each potential EST, as well as the whole farm on which the EST was located were evaluated from the estimated emissions from water-holding structures, barns, etc., all normalized by the appropriate nitrogen excretion rate at the potential EST farm, as well as from the appropriate conventional farm. This study showed that ammonia emissions were reduced by all but one potential EST for both experimental periods. However, on the basis of our evaluation results and analysis and available information in the scientific literature, the evaluated alternative technologies may require additional technical modifications to be qualified as unconditional ESTs relative to NH3 emissions reductions.}, number={9}, journal={JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION}, author={Aneja, Viney P. and Arya, S. Pal and Rumsey, Ian C. and Kim, D. -S. and Bajwa, K. and Arkinson, H. L. and Semunegus, H. and Dickey, D. A. and Stefanski, L. A. and Todd, L. and et al.}, year={2008}, month={Sep}, pages={1145–1157} }
 @article{aneja_arya_kim_rumsey_arkinson_semunegus_bajwa_dickey_stefanski_todd_et al._2008, title={Characterizing ammonia emissions from swine farms in eastern north carolina: Part 1-conventional lagoon and spray technology for waste treatment}, volume={58}, ISSN={["1047-3289"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-53849107841&partnerID=MN8TOARS}, DOI={10.3155/1047-3289.58.9.1130}, abstractNote={Abstract Ammonia (NH3) fluxes from waste treatment lagoons and barns at two conventional swine farms in eastern North Carolina were measured. The waste treatment lagoon data were analyzed to elucidate the temporal (seasonal and diurnal) variability and to derive regression relationships between NH3 flux and lagoon temperature, pH and ammonium content of the lagoon, and the most relevant meteorological parameters. NH3 fluxes were measured at various sampling locations on the lagoons by a flow-through dynamic chamber system interfaced to an environmentally controlled mobile laboratory. Two sets of open-path Fourier transform infrared (FTIR) spectrometers were also used to measure NH3 concentrations for estimating NH3 emissions from the animal housing units (barns) at the lagoon and spray technology (LST) sites.Two different types of ventilation systems were used at the two farms. Moore farm used fan ventilation, and Stokes farm used natural ventilation. The early fall and winter season intensive measurement campaigns were conducted during September 9 to October 11, 2002 (lagoon temperature ranged from 21.2 to 33.6 °C) and January 6 to February 2, 2003 (lagoon temperature ranged from 1.7 to 12 °C), respectively. Significant differences in seasonal NH3 fluxes from the waste treatment lagoons were found at both farms. Typical diurnal variation of NH3 flux with its maximum value in the afternoon was observed during both experimental periods. Exponentially increasing flux with increasing surface lagoon temperature was observed, and a linear regression relationship between logarithm of NH3 flux and lagoon surface temperature (T l) was obtained. Correlations between lagoon NH3 flux and chemical parameters, such as pH, total Kjeldahl nitrogen (TKN), and total ammoniacal nitrogen (TAN) were found to be statistically insignificant or weak. In addition to lagoon surface temperature, the difference (D) between air temperature and the lagoon surface temperature was also found to influence the NH3 flux, especially when D > 0 (i.e., air hotter than lagoon). This hot-air effect is included in the statistical-observational model obtained in this study, which was used further in the companion study (Part II), to compare the emissions from potential environmental superior technologies to evaluate the effectiveness of each technology.}, number={9}, journal={JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION}, author={Aneja, Viney P. and Arya, S. Pal and Kim, D. -S. and Rumsey, Ian C. and Arkinson, H. L. and Semunegus, H. and Bajwa, K. S. and Dickey, D. A. and Stefanski, L. A. and Todd, L. and et al.}, year={2008}, month={Sep}, pages={1130–1144} }
 @article{reed_dickey_burkholder_kinder_brownie_2008, title={Water level variations in the Neuse and Pamlico Estuaries, North Carolina due to local and remote forcing}, volume={76}, ISSN={["1096-0015"]}, DOI={10.1016/j.ecss.2007.05.049}, abstractNote={Water level time series records from the Neuse and Pamlico River Estuaries were statistically compared to local and distant wind field data, water level records within the Pamlico Sound and also coastal ocean sites to determine the relative contribution of each time series to water levels in the Neuse and Pamlico Estuaries. The objectives of this study were to examine these time series data using various statistical methods (i.e. autoregressive, empirical orthogonal function analysis (EOF), exploratory data analysis (EDA)) to determine short- and long-time-scale variability, and to develop predictive statistical models that can be used to estimate past water level fluctuations in both the Neuse Estuary (NE) and Pamlico Estuary (PE). Short- and long-time-scale similarities were observed in all time series of estuarine, Pamlico Sound and subtidal coastal ocean water level and wind component data, due to events (nor'easters, fronts and tropical systems) and seasonality. Empirical orthogonal function analyses revealed a strong coastal ocean and wind field contribution to water level in the NE and PE. Approximately 95% of the variation was captured in the first two EOF components for water level data from the NE, sound and coastal ocean, and 70% for the PE, sound and coastal ocean. Spectral density plots revealed strong diurnal signals in both wind and water level data, and a strong cross correlation and coherency between the NE water level and the North/South wind component. There was good agreement between data and predictions using autoregressive statistical models for the NE (R2 = 0.92) and PE (R2 = 0.76). These methods also revealed significant autoregressive lags for the NE (days 1 and 3) and for the PE (days 1, 2 and 3). Significant departures from predictions are attributed to local meteorological and hydrological events. The autoregressive techniques showed significant predictive improvement over ordinary least squares methods. The results are considered within the context of providing long time-scale hindcast data for the two estuaries, and the importance of these data for multidisciplinary researchers and managers.}, number={2}, journal={ESTUARINE COASTAL AND SHELF SCIENCE}, author={Reed, Robert E. and Dickey, David A. and Burkholder, Joann M. and Kinder, Carol A. and Brownie, Cavell}, year={2008}, month={Jan}, pages={431–446} }
 @article{gustafson_ellis_beattie_chang_dickey_robinson_marenghi_moffett_page_2007, title={Hydrographics and the timing of infectious salmon anemia outbreaks among Atlantic salmon (Salmo salar L.) farms in the Quoddy region of Maine, USA and New Brunswick, Canada}, volume={78}, ISSN={["1873-1716"]}, DOI={10.1016/j.prevetmed.2006.09.006}, abstractNote={Infectious salmon anemia (ISA) has caused severe morbidity and mortality in farmed Atlantic salmon in North America, Norway, Scotland and the Faroe Islands. The Quoddy region of Maine, United States of America (USA), and New Brunswick (NB), Canada is characterized by extensive tidal mixing and close proximity between farms. This region is also prone to recurrent appearances of ISA, though control measures limit disease spread and severity on infected farms. We conducted a retrospective longitudinal analysis of the apparent impact of hydrographics on the incidence and timing of ISA outbreaks on Atlantic salmon (Salmo salar L.) farms in the Quoddy region from May 2002 to August 2004. A time-series cross-sectional regression of 32 farms over 28 months demonstrated a limited, but statistically significant, spatio-temporal clustering of ISA outbreaks linked hydrographically. New outbreaks correlated temporally with those occurring on-site 1 and 3 months prior, and those occurring within one tidal-excursion upstream the same month. Other risk factors included holdover of previous year-class fish, wharf sharing, and possibly harvests of cages infected in previous months. Conclusions suggest that tidal dispersion does play a role in ISAV transmission in the Quoddy region. Dispersal of free virus and/or tidal distribution of lice or other hydrographically influenced vectors or fomites could all contribute to the spatio-temporal patterns described.}, number={1}, journal={PREVENTIVE VETERINARY MEDICINE}, author={Gustafson, L. L. and Ellis, S. K. and Beattie, M. J. and Chang, B. D. and Dickey, D. A. and Robinson, T. L. and Marenghi, F. P. and Moffett, P. J. and Page, F. H.}, year={2007}, month={Jan}, pages={35–56} }
 @article{pietrafesa_buckley_peng_bao_liu_peng_xie_dickey_2007, title={On coastal ocean systems, coupled model architectures, products and services: Morphing from observations to operations and applications}, volume={41}, ISSN={["1948-1209"]}, DOI={10.4031/002533207787442268}, abstractNote={The national build-up of “coastal ocean observing systems” (COOSs) to establish the coastal observing component of the national component of the Integrated Ocean Observing System (IOOS) network must be well organized and must acknowledge, understand and address the needs
 of the principal clients, the federal, and in some cases state as well, agencies that provide financial support if it is to have substantive value. The funds being spent in support of COOS should be invested in pursuit of the establishment of the National Backbone (NB) that is needed: to greatly
 improve atmospheric, oceanic and coastal “weather” forecasting, broadly defined; for ecosystem management; and to document climate variability and change in coastal zones. However, this process has not occurred in a well conceived, orderly, well integrated manner due to historical
 and cultural bases and because of local priorities. A sub-regional effort that is designed to meet federal agency needs and mission responsibilities with an emphasis on meeting societal needs is presented by way of example to show that university and industry partners with federal agencies
 have an important role to play in the future of building out ocean and coastal observing and prediction systems and networks.}, number={1}, journal={MARINE TECHNOLOGY SOCIETY JOURNAL}, author={Pietrafesa, L. J. and Buckley, E. B. and Peng, M. and Bao, S. and Liu, H. and Peng, S. and Xie, L. and Dickey, D. A.}, year={2007}, pages={44–52} }
 @article{pietrafesa_kelleher_karl_davidson_peng_bao_dickey_xie_liu_xia_2006, title={A new architecture for coastal inundation and flood warning prediction}, volume={40}, ISSN={["0025-3324"]}, DOI={10.4031/002533206787353205}, abstractNote={The marine atmosphere, coastal ocean, estuary, harbor and river water systems constitute a physically coupled system. While these systems have always been heavily impacted by coastal storms, increases in population density, infrastructure, and personal and business merchandise have
 exacerbated the economic and personal impacts of these events over the past half century. As such there has been increased focus on the need for more timely and accurate forecasts of impending events. Traditionally model forecast architectures for coastal storm surge, flooding and inundation
 of coastal and inland areas have taken the approach of dealing with each system separately: rivers, estuaries, harbors and offshore facing areas. However, given advances in coupled modeling and the availability of real-time data, the ability to accurately predict and project coastal, estuary
 and inland flooding related to the passage of high energy and wet atmospheric events is rapidly emerging and requires a new paradigm in system architecture. No longer do monthly averaged winds or river discharge or water levels have to be invoked in developing hindcasts for planning purposes
 or for real-time forecasts. In 1999 a hurricane associated flood on the North Carolina coast took 56 lives and caused more than $6 billion in economic impacts. None of the models existing at that time were able to properly forecast the massive flooding and clearly called for a new model
 paradigm. Here we propose a model system that couples atmospheric information to fully three dimensional, non-linear time dependent ocean basin, coastal and estuary hydrodynamic models coupled to interactive river models with input of real or modeled winds, observed or modeled precipitation,
 measured and modeled water levels, and streamflow. The river and estuarine components must both be capable of going into modes of storage or accelerated discharge. Spatial scales must downscale in the horizontal from thousands to tens meters and in the vertical from hundreds to several centimeters.
 Topography and elevation data should be of the highest resolution available, necessary for highly accurate predictions of the timing and location of the inundation and retreat of flood waters. Precipitation information must be derived from the optimal mix of direct radar, satellite and ground-based
 observations. Creating the capability described above will advance the modernization of hydrologic services provided by the National Oceanic & Atmospheric Administration and provide more accurate and timely forecasts and climatologies of coastal and estuary flooding. The goal of these
 climatologies and improved forecasts is to provide better information to local and regional planners, emergency managers, highway patrols and to improve the capacity of coastal communities to mitigate against the impacts of coastal flooding.}, number={4}, journal={MARINE TECHNOLOGY SOCIETY JOURNAL}, author={Pietrafesa, L. J. and Kelleher, K. and Karl, T. and Davidson, M. and Peng, M. and Bao, S. and Dickey, D. and Xie, L. and Liu, H. and Xia, M.}, year={2006}, pages={71–77} }
 @article{dickey_dickey_stewart_willson_2006, title={An Automated Statistical Process Control Study of Inline Mixing Using Spectrophotometric Detection}, volume={83}, DOI={10.1021/ed083p110}, abstractNote={Statistical process control (SPC) charts are used to distinguish natural, random variations in a process parameter from fluctuations associated with an assignable cause, such as equipment malfunction or operator error. SPC charts are widely used in industry for quality and process control. In fact, feedback from recent graduates of the undergraduate chemical engineering program indicates that familiarity with SPC charts is one of the most valuable skills for newly hired process engineers. In the following experiment, students are introduced to the concept of SPC through a simple inline mixing experiment. Students learn to create SPC control charts and, more importantly, to understand their function.}, number={1}, journal={Journal of Chemical Education}, publisher={American Chemical Society (ACS)}, author={Dickey, David A. and Dickey, Michael D. and Stewart, Michael D. and Willson, C. Grant}, year={2006}, month={Jan}, pages={110} }
 @misc{burkholder_dickey_kinder_reed_mallin_mciver_cahoon_melia_brownie_smith_et al._2006, title={Comprehensive trend analysis of nutrients and related variables in a large eutrophic estuary: A decadal study of anthropogenic and climatic influences}, volume={51}, ISSN={["1939-5590"]}, DOI={10.4319/lo.2006.51.1_part_2.0463}, abstractNote={We used a decadal data set, with weekly to biweekly sampling in April—October and monthly sampling in November—March, to characterize climatic (hurricane‐level storms, a sustained 3‐yr drought) and anthropogenic influences on N and P concentrations and loadings to a large eutrophic, poorly flushed estuary, the Neuse Estuary of the Albemarle—Pamlico Estuarine System. Mass volume transport data were obtained with cross‐estuary transect flow measurements taken near the entrance to the estuary. Although trends were minimally influenced by hurricanes, analyses were significantly affected by the sustained drought near the end of the study. As examples, decreasing trends in total N (TN), total P (TP), and bottom‐water dissolved oxygen concentrations, and in TN loadings were significant considering all data, but these trends were not significant when the sustained drought was excluded from analysis. In addition, the trend in TN loading was especially sensitive to the initial sampling period. NH4+ concentrations dramatically increased (overall by ~500%) as a persistent trend regardless of attempts to control for climatic events. An increasing trend in NH4+ also was documented in an adjacent, rapidly flushed Coastal Plain estuary, the Cape Fear. The NH4+ data suggest a regional‐scale effect of high inputs from inadequately controlled, increasing nonpoint sources. The fragility of TN loading trends, the striking increase in NH4+ concentrations, and the lack of management emphasis on controlling nonpoint sources such as “new” industrialized swine production collectively do not support recent reports of achievement of a 30% reduction in TN loading to the Neuse. Nonpoint sources remain a critical target for reduction to alleviate the negative effects of cultural eutrophication in this system, as in many estuaries throughout the world.}, number={1}, journal={LIMNOLOGY AND OCEANOGRAPHY}, author={Burkholder, JoAnn M. and Dickey, David A. and Kinder, Carol A. and Reed, Robert E. and Mallin, Michael A. and McIver, Matthew R. and Cahoon, Lawrence B. and Melia, Greg and Brownie, Cavell and Smith, Joy and et al.}, year={2006}, month={Jan}, pages={463–487} }
 @inproceedings{lin_chao_hao_kim_palmieri_kim_dickey_ho_willson_2006, title={Planarization for reverse-tone step and flash imprint lithography - art. no. 61512G}, volume={6151}, booktitle={Proceedings of the society of photo-optical instrumentation engineers}, author={Lin, M. W. and Chao, H. L. and Hao, J. J. and Kim, E. K. and Palmieri, F. and Kim, W. C. and Dickey, M. and Ho, P. S. and Willson, C. G.}, year={2006}, pages={G1512–1512} }
 @article{low_bielory_qureshi_dunn_stuhlmiller_dickey_2006, title={The relation of stroke admissions to recent weather, airborne allergens, air pollution, seasons, upper respiratory infections, and asthma incidence, September 11, 2001, and day of the week}, volume={37}, ISSN={["0039-2499"]}, DOI={10.1161/01.STR.0000214681.94680.66}, abstractNote={
            
              Background and Purpose—
            
            Some previous research links stroke incidence to weather, some links strokes to air pollution, and some report seasonal effects. Alveolar inflammation was proposed as the mechanistic link. We present a unified model of time, weather, pollution, and upper respiratory infection (URI) incidence.
          }, number={4}, journal={STROKE}, author={Low, RB and Bielory, L and Qureshi, AI and Dunn, V and Stuhlmiller, DFE and Dickey, DA}, year={2006}, month={Apr}, pages={951–957} }
 @article{phillips_ghosh_dickey_2005, title={Stress relaxation of tufted carpets and carpet components: Analysis of the tufted carpet structure}, volume={75}, ISSN={["1746-7748"]}, DOI={10.1177/0040517505053844}, abstractNote={ Dimensional stability of tufted carpets has been a continuing problem in the carpet industry for years. When a tufted carpet is installed by the stretch-in method, it experiences stress relaxation over time which can cause the carpet to buckle, wrinkle and become loose with the only option being a costly re-stretching of the carpet. Analysis of the various components of the tufted carpet composite structure was performed to identify the role each component plays in the phenomenon of stress relaxation. A biaxial loading system was used to test various samples of the primary backing alone, primary backing after tufting (with tufts), secondary backing alone, and the finished carpet after attaching the backings with various binder weights per area. The four variables under consideration included primary and secondary backing constructions, tufting density, and latex weight. A rheological model that includes representations of each component in the carpet structure was developed and will be presented in a following paper. }, number={6}, journal={TEXTILE RESEARCH JOURNAL}, author={Phillips, KJ and Ghosh, TK and Dickey, DA}, year={2005}, month={Jun}, pages={485–491} }
 @article{huh_dickey_meador_ruhl_2005, title={Temporal analysis of the frequency and duration of low and high streamflow: years of record needed to characterize streamflow variability}, volume={310}, ISSN={["1879-2707"]}, DOI={10.1016/j.jhydrol.2004.12.008}, abstractNote={A temporal analysis of the number and duration of exceedences of high- and low-flow thresholds was conducted to determine the number of years required to detect a level shift using data from Virginia, North Carolina, and South Carolina. Two methods were used—ordinary least squares assuming a known error variance and generalized least squares without a known error variance. Using ordinary least squares, the mean number of years required to detect a one standard deviation level shift in measures of low-flow variability was 57.2 (28.6 on either side of the break), compared to 40.0 years for measures of high-flow variability. These means become 57.6 and 41.6 when generalized least squares is used. No significant relations between years and elevation or drainage area were detected (P>0.05). Cluster analysis did not suggest geographic patterns in years related to physiography or major hydrologic regions. Referring to the number of observations required to detect a one standard deviation shift as ‘characterizing’ the variability, it appears that at least 20 years of record on either side of a shift may be necessary to adequately characterize high-flow variability. A longer streamflow record (about 30 years on either side) may be required to characterize low-flow variability.}, number={1-4}, journal={JOURNAL OF HYDROLOGY}, author={Huh, SH and Dickey, DA and Meador, MR and Ruhl, KE}, year={2005}, month={Aug}, pages={78–94} }
 @article{lee_dickey_2004, title={Limiting distributions of unconditional maximum likelihood unit root test statistics in seasonal time-series models}, volume={25}, ISSN={["0143-9782"]}, DOI={10.1111/j.1467-9892.2004.01814.x}, abstractNote={Abstract.  The likelihood function of a seasonal model, Yt = ρYt−d + et as implemented in computer algorithms under the assumption of stationary initial conditions is a function of ρ which is zero at the point ρ = 1. It is a smooth function for ρ in the above seasonal model with a well‐defined maximum regardless of the data‐generating mechanism. Gonzalez‐Farias (PhD Thesis, North Carolina State University, 1992) proposed tests for unit roots based on maximizing the stationary likelihood function in nonseasonal time series. We extend it to seasonal time series. The limiting distribution of seasonal unit root test statistics based on the unconditional maximum likelihood estimators are shown. Models having a single mean, seasonal means, and a single‐trend variable across the seasons are considered.}, number={4}, journal={JOURNAL OF TIME SERIES ANALYSIS}, author={Lee, T and Dickey, DA}, year={2004}, month={Jul}, pages={551–561} }
 @inbook{pietrafesa_xie_dickey_peng_yan_2003, title={North Carolina State University coastal and estuary storm surge and flood prediction system}, ISBN={1853128341}, booktitle={Ecosystems and Sustainable Development IV}, publisher={Southampton; Boston: WIT Press}, author={Pietrafesa, L. J. and Xie, L. and Dickey, D. A. and Peng, M. and Yan, S.}, editor={E. Tiezzi, C. A. Brebbia and Uso, J. L.Editors}, year={2003}, pages={101–110} }
 @article{dickey_pantula_2002, title={Determining the order of differencing in autoregressive processes (Reprinted)}, volume={20}, ISSN={["1537-2707"]}, DOI={10.1198/073500102753410363}, abstractNote={One way of handling nonstationarity in time series is to compute first differences and fit a model to the differenced series unless the differenced series also looks nonstationary. In that case, second- or higher-order differencing is done. To decide if the current degree of differencing is sufficient, one can look at the autocorrelation function for slow decay. A formal statistical test for the need to difference further is available if one is willing to assume that at most one more difference will render the series stationary. In this article, we present a proper sequence of statistical tests that allows the practitioner to handle cases in which a high order of differencing may be needed. The proper sequence is not the traditional sequence, which begins with a test for a single unit root.}, number={1}, journal={JOURNAL OF BUSINESS & ECONOMIC STATISTICS}, author={Dickey, DA and Pantula, SG}, year={2002}, month={Jan}, pages={18–24} }
 @article{evans_dickey_2002, title={Normalizations for periodogram-based unit root tests}, volume={60}, ISSN={["0167-7152"]}, DOI={10.1016/S0167-7152(02)00154-2}, abstractNote={We explore a periodogram-based unit root test that is invariant to nonzero means and invariant to nuisance parameters in the error series. We present modifications to account for trends and deterministic seasonal components.}, number={4}, journal={STATISTICS & PROBABILITY LETTERS}, author={Evans, BA and Dickey, DA}, year={2002}, month={Dec}, pages={343–350} }
 @article{walker_aneja_dickey_2000, title={Atmospheric transport and wet deposition of ammonium in North Carolina}, volume={34}, ISSN={["1873-2844"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0034114438&partnerID=MN8TOARS}, DOI={10.1016/S1352-2310(99)00499-9}, abstractNote={Wet deposition and transport analysis has been performed for ammonium (NH4+) in North Carolina, USA. Multiple regression analysis is employed to model the temporal trend and seasonality in monthly volume-weighted mean NH4+ concentrations in precipitation from 1983 to 1996 at six National Atmospheric Deposition Program/National Trends Network (NADP/NTN) sites. A significant (p<0.01) increasing trend beginning in 1990, which corresponds to an annual concentration increase of approximately 9.5%, is detected at the rural Sampson County site (NC35), which is located within a densely populated network of swine and poultry operations. This trend is positively correlated with increasing ammonia (NH3) emissions related to the vigorous growth of North Carolina's swine population since 1990, particularly in the state's Coastal Plain region. A source–receptor regression model, which utilizes weekly NH4+ concentrations in precipitation in conjunction with boundary layer air mass back trajectories, is developed to statistically test for the influence of a particular NH3 source region on NH4+ concentrations at surrounding NADP/NTN sites for the years 1995–1996. NH3 emissions from this source region, primarily evolving from swine and poultry operations, are found to increase NH4+ concentration in precipitation at sites up to ≈80 km away. At the Scotland County (NC36) and Wake County (NC41) sites, mean NH4+ concentrations show increases of at least 44% for weeks during which 25% or more back trajectories are influenced by this source region.}, number={20}, journal={ATMOSPHERIC ENVIRONMENT}, author={Walker, JT and Aneja, VP and Dickey, DA}, year={2000}, pages={3407–3418} }
 @article{gonzalez-farias_dickey_1999, title={Unit root test: An unconditional maximum likelihood approach}, volume={5}, number={1}, journal={Boletin De La Sociedad Matematica Mexicana}, author={Gonzalez-Farias, G. and Dickey, D. A.}, year={1999}, pages={199–221} }
 @book{rawling_pantula_dickey_1998, title={Applied regression analysis: A research tool}, ISBN={0387984542}, publisher={New York: Springer}, author={Rawling, J. O. and Pantula, S. G. and Dickey, D. A.}, year={1998} }
 @article{akdi_dickey_1998, title={Periodograms of unit root time series: Distributions and tests}, volume={27}, ISSN={["0361-0926"]}, DOI={10.1080/03610929808832651}, abstractNote={Periodograms are often used to characterize time series. They decompose the variation in the data into periodic components and their statistical properties for stationary series are well understood. The periodogram can be computed for any sequence of numbers and we are interested in studying its statistical properties when the underlying data have a time series structure with a unit root. Knowing these properties gives us the ability to look at nonstationarity on a frequency by frequency basis. The pervasive use of periodogram ordinates in applied work and the frequent occurrence of apparently nonstationary data in practice are sufficient alone to motivate interest in these distributions, however we also suggest a way to use the results in a formal test for unit roots. The test has the advantage of using nonseasonal ordinates of the periodogram, thus being invariant to regular periodicities in the data. Section 1 of the paper is introductory. Section 2 develops the periodogram and a convenient normalizati...}, number={1}, journal={COMMUNICATIONS IN STATISTICS-THEORY AND METHODS}, author={Akdi, Y and Dickey, DA}, year={1998}, pages={69–87} }
 @book{steel_torrie_a._1997, title={Principles and procedures of statistics: A biometrical approach}, ISBN={0070610282}, publisher={New York: McGraw-Hill}, author={Steel, R. G. D. and Torrie, J. H. and A., Dickey D.}, year={1997} }
 @article{said_dickey_1984, title={Testing for unit roots in autoregressive-moving average models of unknown order}, volume={71}, number={3}, journal={Biometrika}, author={Said, S. E. and Dickey, D. A.}, year={1984}, pages={599–607} }
 @article{dickey_fuller_1981, title={LIKELIHOOD RATIO STATISTICS FOR AUTOREGRESSIVE TIME-SERIES WITH A UNIT-ROOT}, volume={49}, ISSN={["1468-0262"]}, DOI={10.2307/1912517}, number={4}, journal={ECONOMETRICA}, author={DICKEY, DA and FULLER, WA}, year={1981}, pages={1057–1072} }
 @article{dickey_fuller_1979, title={DISTRIBUTION OF THE ESTIMATORS FOR AUTOREGRESSIVE TIME-SERIES WITH A UNIT ROOT}, volume={74}, ISSN={["1537-274X"]}, DOI={10.2307/2286348}, number={366}, journal={JOURNAL OF THE AMERICAN STATISTICAL ASSOCIATION}, author={DICKEY, DA and FULLER, WA}, year={1979}, pages={427–431} }