Digital Commons Network^™

Interannual Variability Of Wintertime Temperature On The Inner Continental Shelf Of The Middle Atlantic Bight, Thomas Connolly, Steven Lentz

Faculty Publications

The shallow depth of the inner continental shelf allows for rapid adjustment of the ocean to air-sea exchange of heat and momentum compared with offshore locations. Observations during 2001–2013 are used to evaluate the contributions of air-sea heat flux and oceanic advection to interannual variability of inner-shelf temperature in the Middle Atlantic Bight. Wintertime processes are important for interpreting regional interannual variability at nearshore locations since winter anomalies account for 69–77% of the variance of the annual anomalies and are correlated over broad along-shelf scales, from New England to North Carolina. At the Martha's Vineyard Coastal Observatory on the 12 …

Tangram: A Comprehensive Toolbox For Mobile Element Insertion Detection, Jiantao Wu, Wan Ping Lee, Alistair Ward, Jerilyn A. Walker, Miriam K. Konkel, Mark A. Batzer, Gabor T. Marth

Faculty Publications

© 2014 Wu et al.; licensee BioMed Central Ltd. Background: Mobile elements (MEs) constitute greater than 50% of the human genome as a result of repeated insertion events during human genome evolution. Although most of these elements are now fixed in the population, some MEs, including ALU, L1, SVA and HERV-K elements, are still actively duplicating. Mobile element insertions (MEIs) have been associated with human genetic disorders, including Crohn's disease, hemophilia, and various types of cancer, motivating the need for accurate MEI detection methods. To comprehensively identify and accurately characterize these variants in whole genome next-generation sequencing (NGS) data, a …

Gibbon Genome And The Fast Karyotype Evolution Of Small Apes, Lucia Carbone, R. Alan Harris, Sante Gnerre, Krishna R. Veeramah, Belen Lorente-Galdos, John Huddleston, Thomas J. Meyer, Javier Herrero, Christian Roos, Bronwen Aken, Fabio Anaclerio, Nicoletta Archidiacono, Carl Baker, Daniel Barrell, Mark A. Batzer, Kathryn Beal, Antoine Blancher, Craig L. Bohrson, Markus Brameier, Michael S. Campbell, Oronzo Capozzi, Claudio Casola, Giorgia Chiatante, Andrew Cree, Annette Damert, Pieter J. De Jong, Laura Dumas, Marcos Fernandez-Callejo, Paul Flicek, Nina V. Fuchs, Ivo Gut, Marta Gut, Matthew W. Hahn, Jessica Hernandez-Rodriguez, Ladeana W. Hillier, Robert Hubley, Bianca Ianc, Zsuzsanna Izsvák, Nina G. Jablonski, Laurel M. Johnstone, Anis Karimpour-Fard, Miriam K. Konkel, Dennis Kostka, Nathan H. Lazar, Sandra L. Lee, Lora R. Lewis, Yue Liu, Devin P. Locke, Swapan Mallick, Fernando L. Mendez, Matthieu Muffato, Lynne V. Nazareth, Kimberly A. Nevonen, Majesta O'Bleness, Cornelia Ochis, Duncan T. Odom, Katherine S. Pollard, Javier Quilez, David Reich, Mariano Rocchi, Gerald G. Schumann, Stephen Searle, James M. Sikela, Gabriella Skollar, Arian Smit, Kemal Sonmez, Boudewijn Ten Hallers, Elizabeth Terhune, Gregg W. C. Thomas, Brygg Ullmer, Mario Ventura, Jerilyn A. Walker, Jeffrey D. Wall, Lutz Walter, Michelle C. Ward, Sarah J. Wheelan, Christopher W. Whelan, Simon White, Larry J. Wilhelm, August E. Woerner, Mark Yandell, Baoli Zhu, Michael F. Hammer, Tomas Marques-Bonet, Evan E. Eichler, Lucinda Fulton, Catrina Fronick, Donna M. Muzny, Wesley C. Warren, Kim C. Worley, Jeffrey Rogers, Richard K. Wilson, Richard A. Gibbs

Faculty Publications

©2014 Macmillan Publishers Limited. All rights reserved. Gibbons are small arboreal apes that display an accelerated rate of evolutionary chromosomal rearrangement and occupy a key node in the primate phylogeny between Old World monkeys and great apes. Here we present the assembly and analysis of a northern white-cheeked gibbon (Nomascus leucogenys) genome. We describe the propensity for a gibbon-specific retrotransposon (LAVA) to insert into chromosome segregation genes and alter transcription by providing a premature termination site, suggesting a possible molecular mechanism for the genome plasticity of the gibbon lineage. We further show that the gibbon genera (Nomascus, Hylobates, Hoolock and …

Space Radiation: The Number One Risk To Astronaut Health Beyond Low Earth Orbit, Jeffery C. Chancellor, Graham B.I. Scott, Jeffrey P. Sutton

Faculty Publications

Projecting a vision for space radiobiological research necessitates understanding the nature of the space radiation environment and how radiation risks influence mission planning, timelines and operational decisions. Exposure to space radiation increases the risks of astronauts developing cancer, experiencing central nervous system (CNS) decrements, exhibiting degenerative tissue effects or developing acute radiation syndrome. One or more of these deleterious health effects could develop during future multi-year space exploration missions beyond low Earth orbit (LEO). Shielding is an effective countermeasure against solar particle events (SPEs), but is ineffective in protecting crew members from the biological impacts of fast moving, highly-charged galactic …

Protozoacidal Trojan-Horse: Use Of A Ligand-Lytic Peptide For Selective Destruction Of Symbiotic Protozoa Within Termite Guts, Amit Sethi, Jennifer Delatte, Lane Foil, Claudia Husseneder

Faculty Publications

© 2014 Sethi et al. For novel biotechnology-based termite control, we developed a cellulose bait containing freeze-dried genetically engineered yeast which expresses a protozoacidal lytic peptide attached to a protozoa-recognizing ligand. The yeast acts as a 'Trojan-Horse' that kills the cellulose-digesting protozoa in the termite gut, which leads to the death of termites, presumably due to inefficient cellulose digestion. The ligand targets the lytic peptide specifically to protozoa, thereby increasing its protozoacidal efficiency while protecting non-target organisms. After ingestion of the bait, the yeast propagates in the termite's gut and is spread throughout the termite colony via social interactions. This …

Antiviral Responses In Mouse Embryonic Stem Cells: Differential Development Of Cellular Mechanisms In Type I Interferon Production And Response, Ruoxing Wang, Jundi Wang, Dhiraj Acharya, Amber M. Paul, Fengwei Bai, Faqing Huang, Yan-Lin Guo

Faculty Publications

We have recently reported that mouse embryonic stem cells (mESCs) are deficient in expressing type I interferons (IFNs) in response to viral infection and synthetic viral RNA analogs (Wang, R., Wang, J., Paul, A. M., Acharya, D., Bai, F., Huang, F., and Guo, Y. L. (2013) J. Biol. Chem. 288, 15926–15936). Here, we report that mESCs are able to respond to type I IFNs, express IFN-stimulated genes, and mediate the antiviral effect of type I IFNs against La Crosse virus and chikungunya virus. The major signaling components in the IFN pathway are expressed in mESCs. Therefore, the basic molecular mechanisms …

Intergeniculate Leaflet Lesions Result In Differential Activation Of Brain Regions Following The Presentation Of Photic Stimuli In Nile Grass Rats, Andrew J. Gall, Lily Yan, Laura Smale, Antonio A. Nunez

Faculty Publications

The intergeniculate leaflet (IGL) plays an important role in the entrainment of circadian rhythms and the mediation of acute behavioral responses to light (i.e., masking). Recently, we reported that IGL lesions in diurnal grass rats result in a reversal in masking responses to light as compared to controls. Here, we used Fos as a marker of neural activation to examine the mechanisms by which the IGL may influence this masking effect of light in grass rats. Specifically, we examined the patterns of Fos activation in retinorecipient areas and in brain regions that receive IGL inputs following 1-h light pulses given …

Transcriptional Profiles Of Bovine In Vivo Pre-Implantation Development, Zongliang Jiang, Jiangwen Sun, Hong Dong, Oscar Luo, Xinbao Zheng, Craig Obergfell, Yong Tang, Jinbo Bi, Rachel O'Neill, Yijun Ruan, Jingbo Chen, Xiuchun Tian

Faculty Publications

© 2014 Jiang et al.; licensee BioMed Central Ltd. Background: During mammalian pre-implantation embryonic development dramatic and orchestrated changes occur in gene transcription. The identification of the complete changes has not been possible until the development of the Next Generation Sequencing Technology.Results: Here we report comprehensive transcriptome dynamics of single matured bovine oocytes and pre-implantation embryos developed in vivo. Surprisingly, more than half of the estimated 22,000 bovine genes, 11,488 to 12,729 involved in more than 100 pathways, is expressed in oocytes and early embryos. Despite the similarity in the total numbers of genes expressed across stages, the nature of …

Verifying And Validating Multirobot Missions, Damian M. Lyons, Ronald C. Arkin, Shu Jiang, Dagon Harrington, Tsung-Ming Liu

Faculty Publications

We have developed an approach that can be used by mission designers to determine whether or not a performance guarantee for their mission software, when carried out under the uncertain conditions of a real-world environment, will hold within a threshold probability. In this paper we demonstrate its utility for verifying multirobot missions, in particular a bounding overwatch mission.

'Sophisticated Robots': Balancing Liability, Regulation, And Innovation, F. Patrick Hubbard

Faculty Publications

Our lives are being transformed by large mobile “sophisticated robots” with increasingly higher levels of autonomy, intelligence, and interconnectivity among themselves. For example, driverless automobiles are likely to become commercially available within a decade. Many people who suffer physical injuries from these robots will seek legal redress for their injury, and regulatory schemes are likely to impose requirements to reduce the number and severity of injuries.

This Article addresses the issue of whether the current liability and regulatory systems provide a fair, efficient method for balancing the concern for physical safety against the need to incentivize the innovation necessary to …

Relative Importance Of Environmental, Geographic, And Spatial Variables On Zooplankton Metacommunities, Tad Dallas, John M. Drake

Faculty Publications

© 2014 Dallas and Drake. Understanding the factors responsible for structuring ecological communities is a central goal in community ecology. Previous work has focused on determining the relative roles of two classes of variables (e.g., spatial and environmental) on community composition. However, this approach may ignore the disproportionate impact of variables within classes, and is often confounded by spatial autocorrelation leading to collinearity among variables of different classes. Here, we combine pattern-based metacommunity and machine learning analyses to characterize metacommunity structure of zooplankton from lakes in the northeast United States and to identify environmental, spatial, and geographic covariates associated with …

Efficiency Of Sampling To Determine Population Size Of Cyrtobagous Salviniae (Coleoptera: Curculionidae), Michael J. Grodowitz, Seth Johnson, Aaron N. Schad

Faculty Publications

Salvinia molesta D. S. Mitchell (Salviniales: Salviniaceae), a small floating fern introduced from South America, is causing an increasing number of problems in the US. Increased reliance on the biocontrol agent, Cyrtobagous salviniae, in the US is becoming more commonplace and several mass-rearing facilities have been developed. Because of differences in sampling protocols including sample size, reporting parameters, and numbers released, an investigation into sampling efficiency was initiated. A small pond in southern Louisiana was sampled in an effort to understand what constitutes an adequate sample size and methodologies needed to estimate numbers of weevils. A clumped distribution in the …

The Association Of The Vanin-1 N131s Variant With Blood Pressure Is Mediated By Endoplasmic Reticulum-Associated Degradation And Loss Of Function, Ya Juan Wang, Bamidele O. Tayo, Anupam Bandyopadhyay, Heming Wang, Tao Feng, Nora Franceschini, Hua Tang, Jianmin Gao, Yun Ju Sung, Robert C. Elston, Scott M. Williams, Richard S. Cooper, Ting Wei Mu, Xiaofeng Zhu, Daniel Levy

Faculty Publications

High blood pressure (BP) is the most common cardiovascular risk factor worldwide and a major contributor to heart disease and stroke. We previously discovered a BP-associated missense SNP (single nucleotide polymorphism)–rs2272996–in the gene encoding vanin-1, a glycosylphosphatidylinositol (GPI)-anchored membrane pantetheinase. In the present study, we first replicated the association of rs2272996 and BP traits with a total sample size of nearly 30,000 individuals from the Continental Origins and Genetic Epidemiology Network (COGENT) of African Americans (P = 0.01). This association was further validated using patient plasma samples; we observed that the N131S mutation is associated with significantly lower plasma vanin-1 …

Effects Of Oil On Terrestrial Vertebrates: Predicting Impacts Of The Macondo Blowout, Christine M.Bergeon Burns, Jill A. Olin, Philip C. Stouffer, Sabrina S. Taylor, Stefan Woltmann

Faculty Publications

In addition to external oiling, marine oil spills may affect vertebrate animals through degradation of habitat; alterations in food web structure; and contamination of resources by toxic compounds, including polycyclic aromatic hydrocarbons. These processes are not well understood for vertebrates breeding and foraging in terrestrial ecosystems affected by oil, such as coastal marshes that were heavily oiled following the 2010 Macondo oil spill. Here, we review what is known about the ecological and physiological effects of oil exposure on vertebrates in general. We then apply these concepts to salt-marsh vertebrates, with special reference to our ongoing monitoring of impacts and …

Effects Of Oil Spills On Terrestrial Arthropods In Coastal Wetlands, Steven C. Pennings, Brittany D. Mccall, Linda Hooper-Bui

Faculty Publications

Coastal wetlands are important to human well-being and vulnerable to oil spills. Research on biotic effects of oil has been focused on microbes, plants, and benthic invertebrates, neglecting terrestrial arthropods. We review how oil affects terrestrial arthropods in coastal marshes and suggest future research topics. Terrestrial arthropods play important ecological roles in coastal marshes, affecting primary production and decomposition and providing food to terrestrial and marine vertebrates. Some species are pests and disease vectors for humans and livestock. Terrestrial arthropods are sensitive to oil exposure and are suppressed even in lightly oiled sites where plants are not affected. Some arthropods …

Oh, Behave! Behavior As An Interaction Between Genes & The Environment, Emily G. Weigel, Michael Denieu, Andrew J. Gall

Faculty Publications

This lesson is designed to teach students that behavior is a trait shaped by both genes and the environment. Students will read a scientific paper, discuss and generate predictions based on the ideas and data therein, and model the relationships between genes, the environment, and behavior. The lesson is targeted to meet the educational goals of undergraduate introductory biology, evolution, and animal behavior courses, but it is also suitable for advanced high school biology students. This lesson meets the criteria for the Next Generation Science Standard HS-LS4, Biological Evolution: Unity and Diversity (NGSS Lead States, 2013).

Improving The Efficiency Of Electrical Stimulation Activities After Spinal Cord Injury, David Dolbow, William R. Holcomb, Ashraf Gorgey

Faculty Publications

In order to enhance spinal cord injury (SCI) rehabilitation programs using neuromuscular electrical stimulation (NMES) and functional electrical stimulation (FES) it is important to examine the manner in which muscle fibers are recruited and the dose–response relationship. A review of the literature suggests that premature force decline and early fatigue with NMES and FES activities may be alleviated with decreased current frequency and increased current intensity. Dose–response relationships with NMES and FES are dependent on the goals of interest as reversing muscle atrophy can be achieved with activities 2–3 times per week for 6 or more weeks while increasing bone …

Influence Of Resource Levels, Organic Compounds And Laboratory Colonization On Interspecific Competition Between The Asian Tiger Mosquito Aedes Albopictus (Stegomyia Albopicta) And The Southern House Mosquito Culex Quinquefasciatus, D.W. Allgood, Donald A. Yee

Faculty Publications

The mosquitoes Aedes albopictus (Stegomyia albopicta) (Skuse) and Culex quinquefasciatus (Say) (Diptera: Culicidae) are common inhabitants of tyres and other artificial containers, which constitute important peridomestic mosquito breeding habitats. We tested the hypotheses that interspecific resource competition between the larvae of these species is asymmetrical, that the concentration of chemicals associated with decomposing detritus affects the competitive outcomes of these species, and that wild and colonized strains of Cx. quinquefasciatus are affected differently by competition with Ae. albopictus. We conducted two laboratory competition experiments wherein we measured survivorship and estimated population growth (λ′) in both species under …

Molecular Characterization Of Two Opecoelid Trematodes From Fishes In The Gulf Of Mexico, With A Desceiption Of A New Species Of Helicometra, Michael J. Andres, Candis L. Ray, Eric E. Pulis, Stephen S. Curran, Robin M. Overstreet

Faculty Publications

The plagioporine opecoelids Helicometra fasciata (Rudolphi, 1819) Odhner, 1902, and Macvicaria crassigula (Linton, 1910) Bartoli, Bray, and Gibson, 1989 have been reported from fishes in expansive geographic regions, disjointed from their type localities. New material of M. crassigula was collected from near its type locality as well as specimens resembling Helicometra fasciata sensu lato from three triglids in the Gulf of Mexico. Comparisons of the ribosomal DNA (rDNA) sequences, comprising the partial 18S rDNA, internal transcribed spacer region (= ITS1, 5.8S, and ITS2), and partial 28S rDNA gene, from M. crassigula and Helicometra fasciata sensu lato in the Gulf of …

The Lotic Intersite Nitrogen Experiments: An Example Of Successful Ecological Research Collaboration, Linx Collaborators, Walter K. Dodds, Jackson R. Webster, Chelsea L. Crenshaw, Ashley M. Helton, Jonathan M. O'Brien, Eugenia Marti, Anne E. Hershey

Faculty Publications

Collaboration is an essential skill for modern ecologists because it brings together diverse expertise, viewpoints, and study systems. The Lotic Intersite Nitrogen eXperiments (LINX I and II), a 17-y research endeavor involving scores of early- to late-career stream ecologists, is an example of the benefits, challenges, and approaches of successful collaborative research in ecology. The scientific success of LINX reflected tangible attributes including clear scientific goals (hypothesis-driven research), coordinated research methods, a team of cooperative scientists, excellent leadership, extensive communication, and a philosophy of respect for input from all collaborators. Intangible aspects of the collaboration included camaraderie and strong team …

Extended Formation Flight At Transonic Speeds, Andrew Ning, Ilan Kroo, Michael Aftosmis, Marian Nemec, James Kless

Faculty Publications

Aircraft flown in formation can realize significant reductions in induced drag by flying in regions of wake upwash. However, most transports fly at transonic speeds where the impact of compressibility on formation flight is not well understood. This study utilizes an Euler solver to analyze the inviscid aerodynamic forces and moments of transonic wing/body configurations flying in a two-aircraft formation. Formations with large streamwise separation distances (10-50 wingspans) are considered.

This work indicates that compressibility-related drag penalties in formation flight may be eliminated by slowing 2-3% below the nominal out-of-formation cruise Mach number (either at fixed lift coefficient or fixed …

Three-Year Change In The Wellbeing Of Orphaned And Separated Children In Institutional And Family-Based Care Settings In Five Low- And Middle-Income Countries, Kathryn Whetten, Jan Ostermann, Brian W. Pence, Rachel A. Whetten, Lynne C. Messer, Sumedha Ariely, Karen O'Donnell, Augustine I. Wasonga, Vanroth Vann, Dafrosa Itemba, Misganaw Eticha, Ira Madan, Nathan M. Thielman, The Positive Outcomes For Orphans (Pofo) Research Team

Faculty Publications

Background With more than 2 million children living in group homes, or “institutions”, worldwide, the extent to which institution-based caregiving negatively affects development and wellbeing is a central question for international policymakers.

Methods A two-stage random sampling methodology identified community representative samples of 1,357 institution-dwelling orphaned and separated children (OSC) and 1,480 family-dwelling OSC aged 6–12 from 5 low and middle income countries. Data were collected from children and their primary caregivers. Survey-analytic techniques and linear mixed effects models describe child wellbeing collected at baseline and at 36 months, including physical and emotional health, growth, cognitive development and memory, and …

Integration Of Apo-Α-Phycocyanin Into Phycobilisomes And Its Association With FnrLIn The Absence Of The Phycocyanin Α-Subunit Lyase (Cpcf) In Synechocystis Sp. Pcc 6803, Pengpeng Zhang, Laurie K. Frankel, Terry M. Bricker

Faculty Publications

Phycocyanin is an important component of the phycobilisome, which is the principal light-harvesting complex in cyanobacteria. The covalent attachment of the phycocyanobilin chromophore to phycocyanin is catalyzed by the enzyme phycocyanin lyase. The photosynthetic properties and phycobilisome assembly state were characterized in wild type and two mutants which lack holo-α-phycocyanin. Insertional inactivation of the phycocyanin α-subunit lyase (ΔcpcF mutant) prevents the ligation of phycocyanobilin to α-phycocyanin (CpcA), while disruption of the cpcB/A/C2/C1 operon in the CK mutant prevents synthesis of both apo-α-phycocyanin (apo-CpcA) and apo-β-phycocyanin (apo-CpcB). Both mutants exhibited similar light saturation curves under white actinic light illumination conditions, indicating …

Robust Meta-Analysis Shows That Glioma Transcriptional Subtyping Complements Traditional Approaches, Sanghoon Lee, Stephen Piccolo, Kristina Allen-Brady

Faculty Publications

Background Gliomas traditionally have been sub-classified
based on histopathological observations. However, this ap-
proach is subject to inter-observer variability, and histopatho-
logical features may not reflect the biological mechanisms that
drive tumor growth. High-throughput transcriptional profiling
has shown promise in objectively and reproducibly identify-
ing glioma subtypes. Most prior studies have typically used
only modest sample sizes and have sometimes overlooked
important data-processing steps to ensure sample quality and
to evaluate the robustness of quantitative findings. The pur-
pose of our study was to define robust glioma subtypes by
applying rigorous preprocessing and validation steps to 1,952
microarray samples aggregated …

Effects Of Caste On The Expression Of Genes Associated With Septic Injury And Xenobiotic Exposure In The Formosan Subterranean Termite, Claudia Husseneder, Dawn M. Simms

Faculty Publications

As social insects, termites live in densely populated colonies with specialized castes under conditions conducive to microbial growth and transmission. Furthermore, termites are exposed to xenobiotics in soil and their lignocellulose diet. Therefore, termites are valuable models for studying gene expression involved in response to septic injury, immunity and detoxification in relation to caste membership. In this study, workers and soldiers of the Formosan subterranean termite, Coptotermes formosanus, were challenged by bacterial injection or by no-choice feeding with a sublethal concentration (0.5%) of phenobarbital. Constitutive and induced expression of six putative immune response genes (two encoding for lectin-like proteins, one …

Discovery Of Common Sequences Absent In The Human Reference Genome Using Pooled Samples From Next Generation Sequencing, Yu Liu, Mehmet Koyutürk, Sean Maxwell, Min Xiang, Martina Veigl, Richard S. Cooper, Bamidele O. Tayo, Li Li, Thomas Laframboise, Zhenghe Wang, Xiaofeng Zhu, Mark R. Chance

Faculty Publications

Background: Sequences up to several megabases in length have been found to be present in individual genomes but absent in the human reference genome. These sequences may be common in populations, and their absence in the reference genome may indicate rare variants in the genomes of individuals who served as donors for the human genome project. As the reference genome is used in probe design for microarray technology and mapping short reads in next generation sequencing (NGS), this missing sequence could be a source of bias in functional genomic studies and variant analysis. One End Anchor (OEA) and/or orphan reads …

Synthesis And In Vitro Evaluation Of Bbb Permeability, Tumor Cell Uptake, And Cytotoxicity Of A Series Of Carboranylporphyrin Conjugates, N. V.S.Dinesh K. Bhupathiraju, Xiaoke Hu, Zehua Zhou, Frank R. Fronczek, Pierre Olivier Couraud, Ignacio A. Romero, Babette Weksler, M. Graça H. Vicente

Faculty Publications

A series of tri[(p-carboranylmethylthio)tetrafluorophenyl]porphyrin conjugates of linear and branched polyamines, glucose, arginine, tri(ethylene glycol), and Tyr-d-Arg-Phe-β-Ala (YRFA) peptide were synthesized. These conjugates were investigated for their BBB permeability in human hCMEC/D3 brain endothelial cells, and their cytotoxicity and uptake were assessed using human glioma T98G cells. For comparison purposes, a symmetric tetra[(p- carboranylmethylthio)tetrafluorophenyl]porphyrin was also synthesized, and its crystal structure was obtained. All porphyrin conjugates show low dark cytotoxicity (IC50 > 400 μM) and low phototoxicity (IC 50 > 100 μM at 1.5 J/cm2) toward T98G cells. All conjugates were efficiently taken up by T98G cells, particularly the cationic polyamine and arginine …

Dynamics Of Methane Ebullition From A Peat Monolith Revealed From A Dynamic Flux Chamber System, Zhongjie Yu, Lee D. Slater, Karina V. R. Schafer, Andrew S. Reeve, Ruth K. Varner

Faculty Publications

Methane (CH4) ebullition in northern peatlands is poorly quantified in part due to its high spatiotemporal variability. In this study, a dynamic flux chamber (DFC) system was used to continuously measure CH4 fluxes from a monolith of near‐surface Sphagnum peat at the laboratory scale to understand the complex behavior of CH4 ebullition. Coincident transmission ground penetrating radar measurements of gas content were also acquired at three depths within the monolith. A graphical method was developed to separate diffusion, steady ebullition, and episodic ebullition fluxes from the total CH4 flux recorded and to identify the timing and CH4 content of individual …

Carbon Dynamics On The Louisiana Continental Shelf And Cross-Shelf Feeding Of Hypoxia, Brian Fry, Dubravko Justic, Philip Riekenberg, Erick M. Swenson, R. Eugene Turner, Lixia Wang, Lora Pride, Nancy N. Rabalais, Janis C. Kurtz, John C. Lehrter, Michael C. Murrell, Elizabeth H. Shadwick, Brandon Boyd

Faculty Publications

Large-scale hypoxia regularly develops during the summer on the Louisiana continental shelf. Traditionally, hypoxia has been linked to the vast winter and spring nutrient inputs from the Mississippi River and its distributary, the Atchafalaya River. However, recent studies indicate that much of the shelf ecosystem is heterotrophic. We used data from five late July shelfwide cruises from 2006 to 2010 to examine carbon and oxygen production and identify net autotrophic areas of phytoplankton growth on the Louisiana shelf. During these summer times of moderate river flows, shelfwide pH and particulate organic carbon (POC) consistently showed strong signals for net autotrophy …

Brief Intervention For Truant Youth Sexual Risk Behavior And Marijuana Use, Richard Dembo, Rhissa Briones-Robinson, Kimberly Barrett, Rocio Ungaro, Ken C. Winters, Steven Belenko, Lora M. Karas, Laura Gulledge, Jennifer Wareham

Faculty Publications

Substance use and sexual risk behaviors are common among adolescents, but research has focused attention on alcohol use. Much less is known about the relationship of marijuana use and sexual risk behavior among high-risk, especially truant, youths. We report interim findings from a NIDA-funded experimental, brief intervention (BI) study involving truant youths and their parents/guardians. Longitudinal data were analyzed to study (1) the relationships between the youths' marijuana use and sexual risk behavior and (2) the effects of a substance use BI on their marijuana use and sexual risk behavior. A growth model analysis for parallel processes was conducted to …