Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

2010

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 8071 - 8100 of 8621

Full-Text Articles in Physical Sciences and Mathematics

Augmented Reality Navigation Interfaces Improve Human Performance In End-Effector Controlled Telerobotics, Keshav Chintamani Jan 2010

Augmented Reality Navigation Interfaces Improve Human Performance In End-Effector Controlled Telerobotics, Keshav Chintamani

Wayne State University Dissertations

On the International Space Station (ISS) and space shuttles, the National Aeronautics and Space Administration (NASA) has used robotic manipulators extensively to perform payload handling and maintenance tasks. Teleoperating robots require expert skills and optimal performance is crucial to mission completion and crew safety. Degradation in performance is observed when manual control is mediated through remote camera views, resulting in poor end-effector navigation quality and extended task completion times. This thesis explores the application of three-dimensional augmented reality (AR) interfaces specifically designed to improve human performance during end-effector controlled teleoperations. A modular telerobotic test bed was developed for this purpose …


Critical Values For The Two Independent Samples Winsorized T Test, Piper Alycee Farrell-Singleton Jan 2010

Critical Values For The Two Independent Samples Winsorized T Test, Piper Alycee Farrell-Singleton

Wayne State University Dissertations

ABSTRACT

CRITICAL VALUES FOR THE TWO INDEPENDENT SAMPLES WINSORIZED T TEST

by

PIPER A. FARRELL-SINGLETON

AUGUST 2010

Advisor: Dr. Shlomo Sawilowsky

Major: (Education, Evaluation and Research)

Degree: Doctor of Philosophy

Through Monte Carlo Simulation, this study explores the approximate behavior of the two sample winsorized t test. Samples are drawn from the normal population and symetrically winsorized up to 20%. The two independent samples winsorized t test is then calculated on each sample using Monte Carlo methods using 1,000,000 iterations. The t values are then sorted from low to high and the critical values for both one and two tailed …


Analysis Of Eurycea Hybrid Zone In Eastern Missouri, Bonnie Jean Beasley Jan 2010

Analysis Of Eurycea Hybrid Zone In Eastern Missouri, Bonnie Jean Beasley

Masters Theses

"Evolutionary mechanisms are often difficult to observe in action because evolution generally works slowly over time. Hybrid zones provide a unique opportunity to observe many evolutionary processes, such as reinforcement, because of the rapid changes that tend to occur in these zones. Salamanders provide an ideal model for examining the rapid changes in populations that result from hybridization because many closely-related species lack reproductive barriers. In Missouri, a well-documented hybridization zone exists among the two subspecies Eurycea longicauda longicauda (long-tailed salamander) and E. L. melanopleura (dark-sided salamander). These salamanders inhabit caves, limestone creek beds, and abandoned mine shafts. A closely …


Contribution-Based Priority Assessment In A Web-Based Intelligent Argumentation Network For Collaborative Software Development, Maithili Satyavolu Jan 2010

Contribution-Based Priority Assessment In A Web-Based Intelligent Argumentation Network For Collaborative Software Development, Maithili Satyavolu

Masters Theses

"Decision making is an important aspect of the collaborative software development process which usually involves complex process of conflict resolution. Stakeholders approach decision making process from multiple perspectives and their priorities play a vital role in it. The priority assessment methods used in the argumentation process so far are usually static. Priorities remain constant throughout the decision making process. In order to make the collaborative system more closely replicate real-world scenarios, this work incorporates dynamic priority assessment into a web-based collaborative system which is based on intelligent computational argumentation. It evaluates priorities dynamically for each cycle of decision process based …


Palynology Of The Middle To Upper Eocene Esmeraldas Formation In The Nuevo Mundo Syncline Area, Middle Magdalena Valley Basin, Colombia, Guillermo Rodriguez-Forero Jan 2010

Palynology Of The Middle To Upper Eocene Esmeraldas Formation In The Nuevo Mundo Syncline Area, Middle Magdalena Valley Basin, Colombia, Guillermo Rodriguez-Forero

Masters Theses

"The palynology of the Eocene Esmeraldas Formation in the Middle Magdalena Valley Basin, Colombia was analyzed in order to constrain the age of the unit. This formation is a very important oil reservoir in the Middle Magdalena Valley Basin, which is a product of a fragmentation of a Cenozoic foreland basin by the Northern Andes. It created structural complexities and syntectonic deposition. The lateral continuity of the formation, as well as its correlations with lithostratigraphic units is adjacent basins, are not clearly understood. The Los Corros Fossil Horizon, a mollusk horizon in the upper part of the Esmeraldas Formation, is …


Applying The “Contextual Integrity” Model Of Privacy To Personal Blogs In The Blogoshere, Frances Grodzinsky, Herman T. Tavani Jan 2010

Applying The “Contextual Integrity” Model Of Privacy To Personal Blogs In The Blogoshere, Frances Grodzinsky, Herman T. Tavani

School of Computer Science & Engineering Faculty Publications

In this paper, we analyze some controversial aspects of blogging and the blogosphere from the perspective of privacy. In particular, we focus on Helen Nissenbaum’s theory of privacy as “contextual integrity” and apply it to personal blogs, in general, and the case of the “Washingtonienne” blogger, in particular. We examine the question of whether personal blogs that are not password protected can be considered “normatively private contexts” according to Nissenbaum’s principles of privacy. We argue that they cannot. Using Nissenbaum’s original model, we conclude that privacy expectations for those who disclose personal information in such blogs are unrealistic. We also …


Multispace & Multistructure. Neutrosophic Transdisciplinarity (100 Collected Papers Of Sciences), Vol. Iv, Florentin Smarandache Jan 2010

Multispace & Multistructure. Neutrosophic Transdisciplinarity (100 Collected Papers Of Sciences), Vol. Iv, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

The fourth volume, in my book series of “Collected Papers”, includes 100 published and unpublished articles, notes, (preliminary) drafts containing just ideas to be further investigated, scientific souvenirs, scientific blogs, project proposals, small experiments, solved and unsolved problems and conjectures, updated or alternative versions of previous papers, short or long humanistic essays, letters to the editors - all collected in the previous three decades (1980-2010) – but most of them are from the last decade (2000-2010), some of them being lost and found, yet others are extended, diversified, improved versions. This is an eclectic tome of 800 pages with papers …


Interval Linear Algebra, Florentin Smarandache, W.B. Vasantha Kandasamy Jan 2010

Interval Linear Algebra, Florentin Smarandache, W.B. Vasantha Kandasamy

Branch Mathematics and Statistics Faculty and Staff Publications

This Interval arithmetic or interval mathematics developed in 1950’s and 1960’s by mathematicians as an approach to putting bounds on rounding errors and measurement error in mathematical computations. However no proper interval algebraic structures have been defined or studies. In this book we for the first time introduce several types of interval linear algebras and study them. This structure has become indispensable for these concepts will find applications in numerical optimization and validation of structural designs. In this book we use only special types of intervals and introduce the notion of different types of interval linear algebras and interval vector …


Super Special Codes Using Super Matrices, Florentin Smarandache, W.B. Vasantha Kandasamy, K. Ilanthenral Jan 2010

Super Special Codes Using Super Matrices, Florentin Smarandache, W.B. Vasantha Kandasamy, K. Ilanthenral

Branch Mathematics and Statistics Faculty and Staff Publications

The new classes of super special codes are constructed in this book using the specially constructed super special vector spaces. These codes mainly use the super matrices. These codes can be realized as a special type of concatenated codes. This book has four chapters. In chapter one basic properties of codes and super matrices are given. A new type of super special vector space is constructed in chapter two of this book. Three new classes of super special codes namely, super special row code, super special column code and super special codes are introduced in chapter three. Applications of these …


Rank Distance Bicodes And Their Generalization, Florentin Smarandache, W.B. Vasantha Kandasamy, N. Suresh Babu, R.S. Selvaraj Jan 2010

Rank Distance Bicodes And Their Generalization, Florentin Smarandache, W.B. Vasantha Kandasamy, N. Suresh Babu, R.S. Selvaraj

Branch Mathematics and Statistics Faculty and Staff Publications

In this book the authors introduce the new notion of rank distance bicodes and generalize this concept to Rank Distance n-codes (RD n-codes), n, greater than or equal to three. This definition leads to several classes of new RD bicodes like semi circulant rank bicodes of type I and II, semicyclic circulant rank bicode, circulant rank bicodes, bidivisible bicode and so on. It is important to mention that these new classes of codes will not only multitask simultaneously but also they will be best suited to the present computerised era. Apart from this, these codes are best suited in cryptography. …


Advances And Applications Of Dsmt For Information Fusion (In Chinese), Florentin Smarandache, Jean Dezert Jan 2010

Advances And Applications Of Dsmt For Information Fusion (In Chinese), Florentin Smarandache, Jean Dezert

Branch Mathematics and Statistics Faculty and Staff Publications

No abstract provided.


Large Cardinals, Oliver Pechenik Jan 2010

Large Cardinals, Oliver Pechenik

Honors Papers

Infinite sets are a fundamental object of modern mathematics. Surprisingly, the existence of infinite sets cannot be proven within mathematics. Their existence, or even the consistency of their possible existence, must be justified extra-mathematically or taken as an article of faith. We describe here several varieties of large infinite set that have a similar status in mathematics to that of infinite sets, i.e. their existence cannot be proven, but they seem both reasonable and useful. These large sets are known as large cardinals. We focus on two types of large cardinal: inaccessible cardinals and measurable cardinals. Assuming the existence of …


The Lisa Gravitational Wave Foreground: A Study Of Double White Dwarfs, Ashley J. Ruiter, Krzysztof Belczynski, Matthew Benacquista, Shane L. Larson, Gabriel Williams Jan 2010

The Lisa Gravitational Wave Foreground: A Study Of Double White Dwarfs, Ashley J. Ruiter, Krzysztof Belczynski, Matthew Benacquista, Shane L. Larson, Gabriel Williams

Physics and Astronomy Faculty Publications and Presentations

Double white dwarfs (WDs) are expected to be a source of confusion-limited noise for the future gravitational wave observatory LISA. In a specific frequency range, this \"foreground noise\" is predicted to rise above the instrumental noise and hinder the detection of other types of signals, e.g., gravitational waves arising from stellar-mass objects inspiraling into massive black holes. In many previous studies, only detached populations of compact object binaries have been considered in estimating the LISA gravitational wave foreground signal. Here, we investigate the influence of compact object detached and Roche-Lobe overflow (RLOF) Galactic binaries on the shape and strength of …


Search For Gravitational Waves From Compact Binary Coalescence In Ligo And Virgo Data From S5 And Vsr1, J. Abadie, B. P. Abbott, Matthew Benacquista, Teviet Creighton, Mario C. Diaz, R. Grosso, J. Li, Soumya Mohanty, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Joseph D. Romano, Robert Stone, B. Vaishnav Jan 2010

Search For Gravitational Waves From Compact Binary Coalescence In Ligo And Virgo Data From S5 And Vsr1, J. Abadie, B. P. Abbott, Matthew Benacquista, Teviet Creighton, Mario C. Diaz, R. Grosso, J. Li, Soumya Mohanty, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Joseph D. Romano, Robert Stone, B. Vaishnav

Physics and Astronomy Faculty Publications and Presentations

We report the results of the first search for gravitational waves from compact binary coalescence using data from the Laser Interferometer Gravitational-Wave Observatory and Virgo detectors. Five months of data were collected during the Laser Interferometer Gravitational-Wave Observatory’s S5 and Virgo’s VSR1 science runs. The search focused on signals from binary mergers with a total mass between 2 and 35M⊙. No gravitational waves are identified. The cumulative 90%-confidence upper limits on the rate of compact binary coalescence are calculated for nonspinning binary neutron stars, black hole-neutron star systems, and binary black holes to be 8.7×10−3  yr−1 L−110, 2.2×10−3  yr−1 L−110, …


Fusion Of Imprecise Qualitative Information, Florentin Smarandache, Xinde Li, Xianzhong Dai, Jean Dezert Jan 2010

Fusion Of Imprecise Qualitative Information, Florentin Smarandache, Xinde Li, Xianzhong Dai, Jean Dezert

Branch Mathematics and Statistics Faculty and Staff Publications

In this paper, we present a new 2-tuple linguistic representation model, i.e. Distribution Function Model (DFM), for combining imprecise qualitative information using fusion rules drawn from Dezert-Smarandache Theory (DSmT) framework. Such new approach allows to preserve the precision and efficiency of the combination of linguistic information in the case of either equidistant or unbalanced label model. Some basic operators on imprecise 2-tuple labels are presented together with their extensions for imprecise 2-tuple labels. We also give simple examples to show how precise and imprecise qualitative information can be combined for reasoning under uncertainty. It is concluded that DSmT can deal …


Toward A Pro-Life Environmental Movement, Lucia A. Silecchia Jan 2010

Toward A Pro-Life Environmental Movement, Lucia A. Silecchia

Scholarly Articles

In modern times, the secular environmental movement seems to have taken on an anti-life message, in ways both subtle and direct. This anti-human – and often anti-life – view has crept into the heart of the “mainstream” ecological movement with consequences that can be detrimental to both human dignity and to the environment itself. This essay does not aim to analyze the complexities inherent in economic development, demographic predictions, or climatology. Instead, it is a call to reflect carefully and soberly on the troubling moral consequences of grounding respect for the environment in disrespect for the dignity of the human …


Neutrosophic Bilinear Algebras And Their Generalizations, Florentin Smarandache, W.B. Vasantha Kandasamy Jan 2010

Neutrosophic Bilinear Algebras And Their Generalizations, Florentin Smarandache, W.B. Vasantha Kandasamy

Branch Mathematics and Statistics Faculty and Staff Publications

This book introduces the concept of neutrosophic bilinear algebras and their generalizations to n-linear algebras, n>2. This book has five chapters. The reader should be well-versed with the notions of linear algebras as well as the concepts of bilinear algebras and n- linear algebras. Further the reader is expected to know about neutrosophic algebraic structures as we have not given any detailed literature about it. The first chapter is introductory in nature and gives a few essential definitions and references for the reader to make use of the literature in case the reader is not thorough with the basics. …


United States Land Cover Land Use Change, Albedo And Radiative Forcing: Past And Potential Climate Implications, Christopher A. Barnes Jan 2010

United States Land Cover Land Use Change, Albedo And Radiative Forcing: Past And Potential Climate Implications, Christopher A. Barnes

Electronic Theses and Dissertations

Land Cover Land Use (LCLU) change affects Earth surface properties including albedo that impose a radiative forcing on the climate. Recent spatially explicit satellite derived contemporary LCLU, albedo, and projected LCLU data are used to study the impact of LCLU change from 1973 to 2000, and from 2000 to 2050, on albedo and surface radiative forcing for the conterminous United States. Four research hypotheses concerned with past and potential future climate implications of LCLU change are addressed. The research described in this dissertation makes an important contribution to advancing understanding of the role of LCLU change on the climate system, …


Transition-Metal Ion Exchange Using Poly(Ethylene Glycol) Oligomers As Solvents, Gina M. Canfield, Michael Bizimis, Susan E. Latturner Jan 2010

Transition-Metal Ion Exchange Using Poly(Ethylene Glycol) Oligomers As Solvents, Gina M. Canfield, Michael Bizimis, Susan E. Latturner

Faculty Publications

Poly(ethylene glycol) oligomers have been found to be effective as alternative solvents for the ion exchange of Mn2þ , Fe2 þ , and Co2þ into hydrated and dehydrated Zeolite X (Na80Al80Si112- O384 3 nH2O). When attempted in aqueous solutions, the exchange of these cations quickly leads to destruction of the zeolite structure within 1-2 exchange cycles. However, in PEG oligomer solvents, the structure can be maintained and exchanges of 48% (Co2þ ), 80% (Mn2þ ), and 91% (Fe2þ ) are observed after one cycle under hydrated conditions. When rigorous steps are taken to remove all water from the zeolite before …


A Study Of The Elongation Of Fibrils Of The Alzheimer's Amyloid Beta Protein With A Coarse-Grained Force Field, Ana Rojas Jan 2010

A Study Of The Elongation Of Fibrils Of The Alzheimer's Amyloid Beta Protein With A Coarse-Grained Force Field, Ana Rojas

LSU Doctoral Dissertations

Alzheimer’s disease (AD) is a brain disorder named after the German psychiatrist Alois Alzheimer, who first described the disease in 1906. AD is a form of dementia, characterized by impairment of memory and other intellectual abilities, caused by the loss of neurons and synapses (the structures that permit communication between neurons) in certain regions of the brain. Although the mechanism by which neurons are affected is not yet well understood, research points to a small protein, the beta-amyloid peptide (Abeta), as the first suspect. Ab chains are present in the brains of healthy individuals, but in AD patients, they associate …


Iron (Iii) Oxide And Copper (Ii) Oxide Mediated Formation Of Pcdd/Fs From Thermal Degradation Of 2-Mcp And 1,2-Dcbz, Shadrack Kirwa Nganai Jan 2010

Iron (Iii) Oxide And Copper (Ii) Oxide Mediated Formation Of Pcdd/Fs From Thermal Degradation Of 2-Mcp And 1,2-Dcbz, Shadrack Kirwa Nganai

LSU Doctoral Dissertations

Formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) which occurs inexorably from most thermal and combustion processes constitutes a major toxic component of environmental pollutants. Generally, it is well established that transition metal-mediated reactions account for the majority of PCDD/F emissions from combustion sources. Specifically, both copper and iron ions, which occur abundantly in combustion generated particulate matter, are considered probably the most active in promoting PCDD/F formation typically in the low temperature post-combustion zone and flue gas pollution control devices. It has also been demonstrated that chlorinated phenols are key intermediates in essentially all pathways of PCDD/F formation. Chlorinated benzenes …


Cross-Talk-Free Dual-Color Fluorescence Cross-Correlation Spectroscopy For High-Throughtput Screening, Wonbae Lee Jan 2010

Cross-Talk-Free Dual-Color Fluorescence Cross-Correlation Spectroscopy For High-Throughtput Screening, Wonbae Lee

LSU Doctoral Dissertations

High throughput processing of chemical/biochemical information is critical in many areas, such as genome sequencing, drug discovery and clinical diagnostics. Integral to collecting information at high rates with the necessary throughput is the development of systems that can not only monitor the results with high precision and accuracy, but also prepare and process samples prior to the analytical measurement. To achieve the required throughput, we have conducted work directed toward developing a system that provides detection sensitivity at the single-molecule detection (SMD) level. The research was first focused on the development of a sensitive strategy for the detection of proteins …


Quantifying The Impact Of Data Quality On Searches For Gravitational Waves From Binary Coalescing Systems With Ligo, Jacob Peter Slutsky Jan 2010

Quantifying The Impact Of Data Quality On Searches For Gravitational Waves From Binary Coalescing Systems With Ligo, Jacob Peter Slutsky

LSU Doctoral Dissertations

Gravitational waves are ripples in space-time itself, predicted by Einstein's General theory of relativity, which propagate at the speed of light and are not scattered or extinguished by passing through matter almost at all. In particular, the gravitational waves from the coalescences of binary systems of compact objects, such as neutron stars and black holes, are exciting prospects for observation. The Laser Interferometer Gravitational-wave Observatory experiment intends to make the _x000C_first direct measurement of gravitational waves, and use the results to uncover new astrophysics. These observations will not be limited by extinction from dust and gas, and will probe astrophysical …


Primes Of The Form X² + Ny² In Function Fields, Piotr Maciak Jan 2010

Primes Of The Form X² + Ny² In Function Fields, Piotr Maciak

LSU Doctoral Dissertations

Let n be a square-free polynomial over F_q, where q is an odd prime power. In this work, we determine which irreducible polynomials p in F_q[x] can be represented in the form X^2+nY^2 with X, Y in F_q[x]. We restrict ourselves to the case where X^2+nY^2 is anisotropic at infinity. As in the classical case over Z, the representability of p by the quadratic form X^2+nY^2 is governed by conditions coming from class field theory. A necessary and almost sufficient condition is that the ideal generated by p splits completely in the Hilbert class field H of K=F_q(x,sqrt(-n)) for the …


Computer Simulation Of Ion-Induced Nucleation In The Presence Of Single Ions And Ion Pairs, Samuel Keasler Jan 2010

Computer Simulation Of Ion-Induced Nucleation In The Presence Of Single Ions And Ion Pairs, Samuel Keasler

LSU Doctoral Dissertations

Atmospheric aerosol particles play an important role in climate and human health. Despite their importance, the mechanisms of their formation are still poorly understood. Ion-induced nucleation may play a role in the process, but details are lacking about how the nucleation rate depends on the size, charge, and number of ions in the cluster. In order to better understand the role that ions might play in new particle formation, we have performed a series of AVUS-HR simulations of the water nucleation in the presence of both single ions and ion pairs. These simulations have shown that the location of the …


Investigations Of Structure / Property Interrelationships Of Organic Thin Films Using Scanning Probe Microscopy And Nanolithography, Zorabel Mallorca Lejeune Jan 2010

Investigations Of Structure / Property Interrelationships Of Organic Thin Films Using Scanning Probe Microscopy And Nanolithography, Zorabel Mallorca Lejeune

LSU Doctoral Dissertations

Studies of the surface assembly and molecular organization of organic thin films were studied using scanning probe microscopy (SPM) and scanning probe lithography (SPL). Systems of organic thin films such as n-alkanethiols and pyridyl functionalized porphyrins were characterized at the molecular level, and measurements of the conductive properties of polythiophenes containing in-chain cobaltabisdicarbollides were accomplished. Understanding the self-organization and mechanisms of self-assembly of organic molecules provides fundamental insight for structure/property interrelationships. Investigations of the surface assembly of 5,10-diphenyl-15,20-di-pyridin-4-yl-porphyrin (DPP) on Au(111) were done using SPL methods of nanoshaving and nanografting. Automated computer designs were developed for nanofabrication to provide local …


Modeling The Impacts Of Pulsed Riverine Inflows On Hydrodynamics And Water Quality In The Barataria Bay Estuary, Anindita Das Jan 2010

Modeling The Impacts Of Pulsed Riverine Inflows On Hydrodynamics And Water Quality In The Barataria Bay Estuary, Anindita Das

LSU Doctoral Dissertations

Eutrophication and coastal wetland loss are the major environmental problems affecting estuaries around the world. In Louisiana, controlled diversions of the Mississippi River water back into coastal wetlands are thought to be an important engineering solution that could reverse coastal land loss. There are concerns, however, that freshwater diversions may increase nutrient inputs and create severe eutrophication problems in estuaries and wetlands adjacent to the diversion sites. My dissertation research concerns modeling the effects of the observed and hypothetical freshwater diversion discharges on the hydrodynamics, salinity and water quality in the Barataria estuary, a deltaic estuary in south Louisiana. This …


Studies Of Nanoparticles From A Group Of Uniform Materials Based On Organic Salts (Gumbos), Aaron Tesfai Jan 2010

Studies Of Nanoparticles From A Group Of Uniform Materials Based On Organic Salts (Gumbos), Aaron Tesfai

LSU Doctoral Dissertations

Tesfai, Aaron, B.S., B.A., University of Missouri, Columbia, 2003 Doctor of Philosophy, Spring Commencement 2010 Major: Chemistry Studies of Nanoparticles from a Group of Uniform Materials Based on Organic Salts (GUMBOS) Dissertation directed by Professor Isiah M. Warner Pages in dissertation, 101. Words in abstract, 271. Ionic liquids (ILs) are defined as organic salts composed of ions with melting points at or below 100 °C. ILs have gained considerable attention because of their desirable properties such as low volatility, high thermal stability, and tunability. GUMBOS are an emergent class of organic salts, many of which are ionic liquids (ILs). However, …


Application-Level Optimization Of End-To-End Data Transfer Throughput, Esma Yildirim Jan 2010

Application-Level Optimization Of End-To-End Data Transfer Throughput, Esma Yildirim

LSU Doctoral Dissertations

For large-scale distributed applications, effective use of available network throughput and optimization of data transfer speed is crucial for end-to-end application performance. Today, many regional and national optical networking initiatives such as LONI, ESnet and Teragrid provide high speed network connectivity to their users. However, majority of the users fail to obtain even a fraction of the theoretical speeds promised by these networks due to issues such as sub-optimal protocol tuning, disk bottleneck on the sending and/or receiving ends, and processor limitations. This implies that having high speed networks in place is important but not sufficient for the improvement of …


Early Life History Dynamics Of The Fish Community In The Atchafalaya River Basin, B. Thorpe Halloran Jan 2010

Early Life History Dynamics Of The Fish Community In The Atchafalaya River Basin, B. Thorpe Halloran

LSU Doctoral Dissertations

Seasonal overbank flooding in systems like the Atchafalaya River Basin (ARB) provides the opportunity for fishes in the mainstem to access off-channel areas on the floodplain. Typically, newly inundated floodplain habitats allow adult fishes to add biomass, avoid predation, and potentially, to reproduce. However, in systems like the ARB, the timing, duration, and magnitude of flooding infrequently coincides with known reproductive periods of many fishes assumed to be floodplain-dependent. To quantify the level of floodplain-exploitative fish reproduction in the ARB, I collected larval and juvenile fish with a variety of sampling gear that allowed estimates in both ultra-shallow (< 2-m) and continuously-inundated habitats (headwater lakes, canals, and bayous). A suite of water quality parameters, river stage, flow, and hours of daylight were used to gauge the influence of environmental phenomena on age-0 abundance during both inundation and drawdown. The results of the 19-month study suggest that many taxa do not rely on the floodplain to ensure high survivorship. Interestingly, the reproductive ecologies of many ARB fishes appeared to be largely independent of widespread connectivity. Although an increasing hydrograph appeared to enhance reproductive output, the interannual timing and intensity of spawning showed limited variability. Larval densities were also contrasted with the microcrustacean zooplankton (copepods and cladocerans) population to assess if a potential food limitation existed in the weeks and months following hatching. During the study, increased zooplankter abundance was typically preceded by elevated river-floodplain connectivity. Conversely, as floodwaters receded during the summer, zooplankton abundance declined to lowest levels observed during the study. Overall, there was limited synchronous overlap between the hatchlings of most fish taxa and their zooplankter prey. This could have potentially resulted in starvation and reduced annual recruitment. Yet, my analysis of the factors that regulate larval fish abundance in the ARB suggest that the density of zooplankton was highly significant although high numbers of larvae and zooplankton rarely coincided. Finally, I compared the intraday (morning vs. afternoon) density and mean length of larval fish at fixed sample sites. The results suggest that once-daily ichthyoplankton collections may fail to provide accurate density and length measurements for young fish populations.