Digital Commons Network^™

Large Deviations For Small Noise Diffusions In A Fast Markovian Environment, Amarjit Budhiraja, Paul Dupuis, Arnab Ganguly

Faculty Publications

A large deviation principle is established for a two-scale stochastic system in which the slow component is a continuous process given by a small noise finite dimensional Itô stochastic differential equation, and the fast component is a finite state pure jump process. Previous works have considered settings where the coupling between the components is weak in a certain sense. In the current work we study a fully coupled system in which the drift and diffusion coefficient of the slow component and the jump intensity function and jump distribution of the fast process depend on the states of both components. In …

Mesoscale Effects On Carbon Export: A Global Perspective, C.S. Harrison, M.C. Long, N.S. Lovenduski, J.K. Moore

Faculty Publications

No abstract provided.

Recognizing The Danger Zone: Response Of Female White-Tailed To Discrete Hunting Events, Jeffery D. Sullivan, Stephen S. Ditchkoff, Bret A. Collier, Charles R. Ruth, Joshua B. Raglin

Faculty Publications

The landscape of fear theory proposes that prey should utilize habitat over space and time such that demographic risk is minimized. White-Tailed deer Odocoileus virginianus respond to temporally and spatially predictable threats posed by humans consistent with the landscape of fear theory. However, few studies examining the response of deer to hunting have accounted for the localized nature of risk. To determine if white-Tailed deer are able to recognize and respond to risks posed by hunters relative to specific hunting locations, we equipped 38 female white-Tailed deer with GPS collars August-December 2013-2015. Deer were generally found to increase use of …

Variation In ‘Bayou Belle’ And ‘Beauregard’ Sweetpotato Root Length In Response To Experimental Phosphorus Deficiency And Compacted Layer Treatments, Arthur Villordon, Jeffrey Cole Gregorie, Don Labonte, Awais Khan, Michael Selvaraj

Faculty Publications

Phosphorus deprivation (—P) reduced sweetpotato storage root length (SRL) regardless of the presence or absence of a compacted layer (CL). The combination of — P and the presence of a simulated compacted layer (+CL) reduced SRL relative to the P-sufficient (+P) control plants grown without a compacted layer (—CL) by 44% and 40%, respectively, in ‘Bayou Belle’ and ‘Beauregard’ cultivars. In both cultivars, the combination of — P and — CL also reduced SRL by 36% (‘Bayou Belle’) and 28% (‘Beauregard’) relative to the control plants. There was a significant planting date X cultivar effect in the temporal — P …

Looking At The Big Picture: Understanding How The Oviduct's Dialogue With Gametes And The Embryo Shapes Reproductive Success, Beatriz Fernandez-Fuertes, Beatriz Rodríguez-Alonso, José María Sánchez, Constantine A. Simintiras, Patrick Lonergan, Dimitrios Rizos

Faculty Publications

The oviduct is a tubular organ comprising three distinct anatomical regions (the infundibulum, the ampulla and the isthmus) connecting the ovary and the uterus. Oviductal function is regulated by ovarian hormones, gametes, and embryo-derived factors, for optimally facilitating key reproductive events. A cross-talk is established between the oviduct and the gametes and embryo and this dialogue shapes the microenvironment in which gamete transport, fertilization, and early embryonic development occur. This review aims to address each participant in this conversation in a holistic manner by delineating several advances in the field within the greater context of understanding how oviduct-gamete and oviduct-embryo …

Gluten-Free Bakery And Pasta Products: Prevalence And Quality Improvement, Yupeng Gao, Marlene E. Janes, Busarawan Chaiya, Margaret A. Brennan, Charles S. Brennan, Witoon Prinyawiwatkul

Faculty Publications

An increasing demand of gluten-free (GF) products is caused by a growing number of diagnosed coeliacs and a consumption trend to eliminate allergenic proteins from diet. Driven by the rapidly growing market, comprehensive understanding of GF products is necessary. The purpose of this review was to concisely present an overview of various approaches to improve physicochemical and sensory qualities of GF bread, cake/muffin and pasta/noodle products. Some novel techniques used in GF products were discussed in this review. These techniques included the use of different alternative flours (including GF cereals, pseudo-cereals, legume flours, fruit and vegetable powders and seafood powders), …

Investigating The Role Of Mitochondrial Respiratory Dysfunction During Hexavalent Chromium-Induced Lung Carcinogenesis, James T.F. Wise, Lei Wang, Michael C. Alstott, Ntube N.O. Ngalame, Yuting Wang, Zhuo Zhang, Xianglin Shi

Faculty Publications

Hexavalent chromium [Cr(VI)] is a lung carcinogen and its complete mechanism of action remains to be investigated. Metabolic reprogramming of key energy metabolism pathways (e.g., increased anaerobic glycolysis in the presence of oxygen or “Warburg effect,” dysregulated mitochondrial function, and lipogenesis) are important to cancer cell and tumor survival and growth. In our current understanding of Cr(VI)-induced carcinogenesis, the role for metabolic reprogramming remains unclear. In this study, we treated human lung epithelial cells (BEAS-2B) with Cr(VI) for 6 months and obtained malignantly transformed cells from an isolated colony grown in soft agar. We also used Cr(VI)-transformed cells from two …

Genetic Mapping Of Quantitative Trait Loci For Grain Yield Under Drought In Rice Under Controlled Greenhouse Conditions, Julio Solis, Andres Gutierrez, Venkata Mangu, Eduardo Sánchez Timm, Renesh Bedre, Steve Linscombe, Niranjan Baisakh

Faculty Publications

Drought stress is a constant threat to rice production worldwide. Most modern rice cultivars are sensitive to drought, and the effect is severe at the reproductive stage. Conventional breeding for drought resistant (DR) rice varieties is slow and limited due to the quantitative nature of the DR traits. Identification of genes (QTLs)/markers associated with DR traits is a prerequisite for marker-assisted breeding. Grain yield is the most important trait and to this end drought yield QTLs have been identified under field conditions. The present study reports identification of drought yield QTLs under controlled conditions without confounding effects of other factors …

An Annotated List Of Auchenorrhyncha And Heteroptera Collected In The Coastal Salt Marshes Of The Mississippi Delta In Louisiana, I. M. Sokolov, X. Chen, R. M. Strecker, L. M. Hooper-Bùi

Faculty Publications

Insects that live in the saltwater and brackish marshes, which fringe the northern coast of the Gulf of Mexico, are largely unstudied. During 2011-2013, a survey of insect fauna of the coastal salt marshes of the Mississippi Delta in Louisiana was conducted. We present the species of terrestrial representatives of Heteroptera and Auchenorrhyncha collected during that study. The Auchenorrhyncha are represented by 33 species in 6 families, with Cicadellidae (16 species) and Delphacidae (13 spp.), and are the most diverse. The terrestrial heteropterans are represented by 11 species in 5 families with the majority of species in Miridae (6 spp.). …

Saltmarsh Plants, But Not Fertilizer, Facilitate Invertebrate Recolonization After An Oil Spill, David Samuel Johnson, John W. Fleeger, Maria Rita Riggio, Irving A. Mendelssohn, Qianxin Lin, Sean A. Graham, Donald R. Deis, Aixin Hou

Faculty Publications

Foundation species contribute to the recovery of animal communities from disturbance by engineering, by improving habitat quality, and by regulating food availability. In a salt marsh impacted by the Deepwater Horizon oil spill, we tested the hypothesis that nutrient subsidies would enhance the positive effects of the foundation species Spartina alterniflora on the initial recolonization of benthic invertebrate communities (e.g., copepods, annelids, nematodes) by augmenting food (i.e., microalgae) availability. After two months, plantings of S. alterniflora significantly elevated the densities of the polychaete Capitella capitata, meiofauna-sized annelids, and total macroinfauna over unplanted plots. After 7 months, the significant effect of …

Convergence Analysis Of A Finite Element Approximation Of Minimum Action Methods, Xiaoliang Wan, Haijun Yu, Jiayu Zhai

Faculty Publications

In this work, we address the convergence of a finite element approximation of the minimizer of the Freidlin–Wentzell (F-W) action functional for nongradient dynamical systems perturbed by small noise. The F-W theory of large deviations is a rigorous mathematical tool to study small-noise-induced transitions in a dynamical system. The central task in the application of F-W theory of large deviations is to seek the minimizer and minimum of the F-W action functional. We discretize the F-W action functional using linear finite elements and establish the convergence of the approximation through G-convergence.

Medicalizing Blackness: Making Racial Difference In The Atlantic World, 1780-1840, Alexandra Cornelius

Civil War Book Review

Using compelling evidence collected from archives in the United Kingdom, Jamaica, South Carolina, and Philadelphia, Rana Hogarth argues persuasively that physicians working among enslaved societies in the Atlantic world during the late eighteenth and early nineteenth centuries played a decisive role in the racialization of physiological and physical differences among humans.

Quantifying Episodic Erosion And Transient Storage On The Western Margin Of The Tibetan Plateau, Upper Indus River, Tara N. Jonell, Lewis A. Owen, Andrew Carter, Jean Luc Schwenniger, Peter D. Clift

Faculty Publications

Copyright © University of Washington. Published by Cambridge University Press, 2017. Transient storage and erosion of valley fills, or sediment buffering, is a fundamental but poorly quantified process that may significantly bias fluvial sediment budgets and marine archives used for paleoclimatic and tectonic reconstructions. Prolific sediment buffering is now recognized to occur within the mountainous upper Indus River headwaters and is quantified here for the first time using optically stimulated luminescence dating, petrography, detrital zircon U-Pb geochronology, and morphometric analysis to define the timing, provenance, and volumes of prominent valley fills. This study finds that climatically modulated sediment buffering occurs …

Changes In Estuarine Sediment Phosphorus Fractions During A Large-Scale Mississippi River Diversion, Eric D. Roy, Nhan T. Nguyen, John R. White

Faculty Publications

Ongoing deterioration and loss of wetlands in the Mississippi River delta threatens the survival of Louisiana's coastal ecosystems and human settlements. In response, the State of Louisiana has proposed a $50 billion, 50-year restoration program. A central piece of this program is the reintroduction of Mississippi River water into the deltaic plain using managed diversions that mimic natural flood pulses. These diversions would transport critically needed sediment, but also deliver large nutrient loads. Coastal eutrophication is therefore a concern, particularly blooms of toxin-producing cyanobacteria. The Bonnet Carré Spillway (BCS) is an existing large flood diversion that protects New Orleans and …

Microfluidic Pore Model Study On Physical And Geomechanical Factors Influencing Fluid Flow Behavior In Porous Media, Shuang Cao

LSU Doctoral Dissertations

Fluid flow in porous media is a subject of fundamental importance and relevant to numerous engineering applications. The comprehensive description of fluid interaction parameters containing wetting properties, fluid-fluid displacement ratio, and capillary pressure, are inevitably needed. Moreover, the fine-grained sediments’ response to various pore fluids and migration in porous media influences reservoir geomechanical properties and pore clogging is essential to a better understanding of fluids flow behavior.

This dissertation provides a detailed study of physical and geomechanical factors influencing fluids flow behavior in porous media. The two-dimensional micromodel tests have been conducted under a wide selection of fluids flow conditions. …

Perchlorate-Coupled Carbon Monoxide (Co) Oxidation: Evidence For A Plausible Microbe-Mediated Reaction In Martian Brines, Marisa R. Myers, Gary M. King

Faculty Publications

© 2017 Myers and King. The presence of hydrated salts on Mars indicates that some regions of its surface might be habitable if suitable metabolizable substrates are available. However, several lines of evidence have shown that Mars' regolith contains only trace levels of the organic matter needed to support heterotrophic microbes. Due to the scarcity of organic carbon, carbon monoxide (CO) at a concentration of about 700 parts per million (about 0.4 Pa) might be the single most abundant readily available substrate that could support near-surface bacterial activity. Although a variety of electron acceptors can be coupled to CO oxidation, …

Complete Mitochondrial Genomes Of Three Neotropical Sleeper Gobies: Eleotris Amblyopsis, E. Picta And Hemieleotris Latifasciata (Gobiiformes: Eleotridae), Fernando Alda, Alexandria J. Adams, W. Owen Mcmillan, Prosanta Chakrabarty

Faculty Publications

© 2017 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. We report the first complete mitochondrial genomes of three species of eleotrid fishes from the Pacific and Atlantic watersheds of Panama: Eleotris amblyopsis, E. picta, and Hemieleotris latifasciata. The three species have similar mitochondrial genomes with identical gene order; however, there are differences in the length of control region, 16S rRNA, and in seven of the tRNAs. In addition, ATP8 is one codon shorter in E. picta than in E. amblyopsis or H. latifasciata. We infer a phylogeny for Gobiiformes based on all mitochondrial protein-coding …

Dna Base Excision Repair And Double Strand Break Repair In Human Fibroblast, Mingyang Li

LSU Doctoral Dissertations

In eukaryotes, DNA repair mechanisms detect and repair damaged DNA. DNA damage is primarily caused by a variety of exogenous and endogenous sources. Several types of damage to DNA are repaired by different kinds of DNA repair pathways. This dissertation focused on repair of N-methylpurines (NMPs) and double-strand breaks (DSBs) in human fibroblasts.

NMPs, including N⁷-methylguanine (7MeG) and N³-methyladenine (3MeA), can be induced by environmental methylating agents (e.g. the soil fumigant methyl bromide), chemotherapeutics (e.g. nitrogen mustards), and natural cellular methyl donors like S-adenosylmethionine. In human cells, NMPs are repaired by the multi-step …

Context-Dependent Chemosensory Signaling, Aggression And Neural Activation Patterns In Gravid Female African Cichlid Fish, Karen E. Field, Karen P. Maruska

Faculty Publications

© 2017. Published by The Company of Biologists Ltd . Social animals must constantly assess their environment to make appropriate behavioral decisions. The use of various sensory modalities is imperative in this process and it is hypothesized that the highly conserved brain nuclei comprising the social decisionmaking network (SDMN) integrates social information with an animal's internal state to elicit behavioral responses. Here, we used the highly social African cichlid fish, Astatotilapia burtoni, to investigate whether reproductively receptive (gravid) females show contextual chemosensory signaling, social behaviors and neural activation patterns within the SDMN. We exposed gravid females to different social contexts: …

Global Awakening Of Cryptic Biosynthetic Gene Clusters In Burkholderia Thailandensis, Ashish Gupta, Renesh Bedre, Sudarshan Singh Thapa, Afsana Sabrin, Guannan Wang, Maheshi Dassanayake, Anne Grove

Faculty Publications

© 2017 American Chemical Society. Many bacteria encode biosynthetic proteins that produce a vast array of natural products. These compounds are often synthesized during host invasion as they function as virulence factors. In addition, such secondary metabolites have yielded numerous molecular scaffolds with pharmaceutical and clinical importance. The gene clusters that encode proteins responsible for synthesis of these compounds are typically silenced or "cryptic" under laboratory growth conditions, hampering discovery of novel lead compounds. We report here that MftR is a global repressor of secondary metabolite synthesis in Burkholderia thailandensis and that urate functions as a physiologically relevant inducer of …

Characterization Of Pathogenic Vibrio Parahaemolyticus From The Chesapeake Bay, Maryland, Arlene J. Chen, Nur A. Hasan, Bradd J. Haley, Elisa Taviani, Mitch Tarnowski, Kathy Brohawn, Crystal N. Johnson, Rita R. Colwell, Anwar Huq

Faculty Publications

Vibrio parahaemolyticus is the leading cause of bacterial gastroenteritis associated with seafood consumption in the United States. Here we investigated the presence of virulence factors and genetic diversity of V. parahaemolyticus isolated from water, oyster, and sediment samples from the Chesapeake Bay, Maryland. Of more than 2,350 presumptive Vibrio collected, more than half were confirmed through PCR as V. parahaemolyticus, with 10 encoding both tdh and trh and 6 encoding only trh. Potentially pathogenic V. parahaemolyticus were then serotyped with O1:KUT and O3:KUT predominant. Furthermore, pulsed-field gel electrophoresis was performed and the constructed dendrogram displayed high diversity, as did results …

Habitat Selection, Survival, And Movement Ecology Of The American Woodcock (Scolopax Minor) In Louisiana Usa, Elisa Constancia Elizondo

LSU Master's Theses

The American Woodcock (Scolopax minor) is a migratory upland game species occurring across much of eastern North America. Across its breeding range in the northern U.S. and southern Canada, this species has experienced significant, pervasive declines over the last half century. As woodcock populations continue to decline, active habitat management for this species has become increasingly important.

The state of Louisiana has substantial amounts of woodcock habitat and receives wintering birds from across the woodcock range. However, few data exist regarding survival rates, habitat utilization, and movement patterns across the state.

In order to better manage for woodcock …

Surface Enhanced Raman Scattering (Sers) Substrates And Probes, Srismrita Basu

LSU Doctoral Dissertations

Raman spectroscopy is a well-known technique for complex molecular detection. In Raman spectrometry, laser beam is focused on a sample to generate a unique "fingerprint" of the molecule. The Raman signal is very weak. To overcome this problem nano rough metallic substrates are fabricated to enhance the signal strength. In clinical applications, remote contact and minimally invasive probes inside the specimen are needed.

This research work is divided in: (1) development of Surface Enhanced Raman Scattering (SERS) substrate using gold coated etched aluminum foil, (2) development of the SERS probe using the aluminum based substrate with a single optical fiber …

Dinoflagellate Cysts Track Eutrophication In The Northern Gulf Of Mexico, Andrea M. Price, Melissa M. Baustian, R. Eugene Turner, Nancy N. Rabalais, Gail L. Chmura

Faculty Publications

We examined organic-walled dinoflagellate cysts from one 210Pb-dated sediment core and 39 surface sediment samples from the northern Gulf of Mexico to determine the relationship between nutrient enrichment and cyst assemblages in this region characterized by oxygen deficiency. The core spans from 1962 to 1997 and its sampling location is directly influenced by the Mississippi River plume. Surface sediments were collected in 2006, 2007, 2008, and 2014 and represent approximately 1 to 4 years of accumulation. A total of 57 cyst taxa were recorded, and four heterotrophic taxa in particular were found to increase in the top section (1986–1997) of …

Erosion And Accretion On A Mudflat: The Importance Of Very Shallow-Water Effects, Benwei Shi, James R. Cooper, Paula D. Pratolongo, Shu Gao, T. J. Bouma, Gaocong Li, Chunyan Li, S. L. Yang, Ya Ping Wang

Faculty Publications

Understanding erosion and accretion dynamics during an entire tidal cycle is important for assessing their impacts on the habitats of biological communities and the long-term morphological evolution of intertidal mudflats. However, previous studies often omitted erosion and accretion during very shallow-water stages (VSWS, water depths < 0.20 m). It is during these VSWS that bottom friction becomes relatively strong and thus erosion and accretion dynamics are likely to differ from those during deeper flows. In this study, we examine the contribution of very shallow-water effects to erosion and accretion of the entire tidal cycle, based on measured and modeled time-series of bed-level changes. Our field experiments revealed that the VSWS accounted for only 11% of the duration of the entire tidal cycle, but erosion and accretion during these stages accounted for 35% of the bed-level changes of the entire tidal cycle. Predicted cumulative bed-level changes agree much better with measured results when the entire tidal cycle is modeled than when only the conditions at water depths of >0.2 m (i.e., probe submerged) are considered. These findings suggest that the magnitude of bed-level changes during VSWS should not be neglected when modeling morphodynamic processes. Our results are useful in understanding the mechanisms of micro-topography formation and destruction that often occur at VSWS, and also improve our understanding and modeling ability of coastal morphological …

Species Are Not Most Abundant In The Centre Of Their Geographic Range Or Climatic Niche, Tad Dallas, Robin R. Decker, Alan Hastings

Faculty Publications

© 2017 John Wiley & Sons Ltd/CNRS The pervasive idea that species should be most abundant in the centre of their geographic range or centre of their climatic niche is a key assumption in many existing ecological hypotheses and has been declared a general macroecological rule. However, empirical support for decreasing population abundance with increasing distance from geographic range or climatic niche centre (distance–abundance relationships) remains fairly weak. We examine over 1400 bird, mammal, fish and tree species to provide a thorough test of distance–abundance relationships, and their associations with species traits and phylogenetic relationships. We failed to detect consistent …

Editorial: Special Thematic Issue On Inland Aquatic Ecosystems, Hongchen Jiang, Yongqin Liu, Gary King

Faculty Publications

No abstract provided.

Pyruvate Dehydrogenase Complex (Pdc) Subunits Moonlight As Interaction Partners Of Phosphorylated Stat5 In Adipocytes And Adipose Tissue, Allison J. Richard, Hardy Hang, Jacqueline M. Stephens

Faculty Publications

© 2017 by The American Society for Biochemistry and Molecular Biology, Inc. STAT5 proteins play a role in adipocyte development and function, but their specific functions are largely unknown. To this end, we used an unbiased MS-based approach to identify novel STAT5-interacting proteins. We observed that STAT5A bound the E1 and E2 subunits of the pyruvate dehydrogenase complex (PDC). Whereas STAT5A typically localizes to the cytosol or nucleus, PDC normally resides within the mitochondrial matrix where it converts pyruvate to acetyl-CoA. We employed affinity purification and immunoblotting to validate the interaction between STAT5A and PDC subunits in murine and human …

Swim Bladder Morphology Changes With Female Reproductive State In The Mouth-Brooding African Cichlid Astatotilapia Burtoni, Julie M. Butler, Sarah M. Whitlow, Anwei P. Gwan, Prosanta Chakrabarty, Karen P. Maruska

Faculty Publications

© 2017. Published by The Company of Biologists Ltd. Journal of Experimental Biology. Mouth brooding is an extreme form of parental care in which the brooding parent carries the developing young in their buccal cavity for the duration of development. Brooding fish need to compensate for the brood weight on the anterior portion of their body. For fishes with a compartmentalized swim bladder, gas distribution between the chambers may aid in regulating buoyancy during brooding. To test this hypothesis, we took radiographs of Astatotilapia burtoni to compare the swim bladder morphology of gravid, mouth-brooding and recovering females. Following spawning, females …

Intramyocellular Lipid Droplet Size Rather Than Total Lipid Content Is Related To Insulin Sensitivity After 8 Weeks Of Overfeeding, Jeffrey D. Covington, Darcy L. Johannsen, Paul M. Coen, David H. Burk, Diana N. Obanda, Philip J. Ebenezer, Charmaine S. Tam, Bret H. Goodpaster, Eric Ravussin, Sudip Bajpeyi

Faculty Publications

© 2017 The Obesity Society Objective: Intramyocellular lipid (IMCL) is inversely related to insulin sensitivity in sedentary populations, yet no prospective studies in humans have examined IMCL accumulation with overfeeding. Methods: Twenty-nine males were overfed a high-fat diet (140% caloric intake, 44% from fat) for 8 weeks. Measures of IMCL, whole-body fat oxidation from a 24-hour metabolic chamber, muscle protein extracts, and muscle ceramide measures were obtained before and after the intervention. Results: Eight weeks of overfeeding did not increase overall IMCL. The content of smaller lipid droplets peripherally located in the myofiber decreased, while increases in larger droplets correlated …