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2006

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Articles 4261 - 4290 of 5872

Full-Text Articles in Physical Sciences and Mathematics

Assessment Of Wind Power Potential For Coastal Areas Of Pakistan, M. Akhlaque Ahmed, Firoz Ahmed, M. Wasim Akhtar Jan 2006

Assessment Of Wind Power Potential For Coastal Areas Of Pakistan, M. Akhlaque Ahmed, Firoz Ahmed, M. Wasim Akhtar

Turkish Journal of Physics

Selected coastal areas of Pakistan (Karachi, Ormara, Jivani and Pasni) were studied for the possibility of wind energy generation, using available meteorological data. Wind speed pattern, Extractable Wind power, Wind Energy and associated Weibull parameter for these coastal areas have been examined. The analysis also includes seasonal changes in wind speed values. The power output using fast and slow wind machines using different blade diameters have been estimated to explore the possible use for irrigation deep well pumping and small scale power generation. Along with this, 4 KW and 20 KW aero generators were also examined. It was found that, …

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Effect Of Thermal Annealing On The Band Gap And Optical Properties Of Chemical Bath Deposited Znse Thin Films, F. I. Ezema, A. B. C. Ekwealor, R. U. Osuji Jan 2006

Effect Of Thermal Annealing On The Band Gap And Optical Properties Of Chemical Bath Deposited Znse Thin Films, F. I. Ezema, A. B. C. Ekwealor, R. U. Osuji

Turkish Journal of Physics

Zinc selenide (ZnSe) thin films were deposited on glass substrate using the chemical bath deposition method at room temperature from aqueous solutions of zinc sulphate and sodium selenosulfate in which sodium hydroxide was employed as complexing agents. The `as-deposited' ZnSe thin films are red in color and annealed in oven at 473 K for 1 hour and on a hot plate in open air at 333 K for 5 minutes, affecting the morphological and optical properties. Optical properties such as absorption coefficient \alpha and extinction coefficient k, were determined using the absorbance and transmission measurement from Unico UV-2102 PC spectrophotometer, …

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Phase Distribution Of The Output Of Jaynes-Cummings Model With The Superposition Of Squeezed Displaced Fock States, Gamal Mohamed Abd Al-Kader Jan 2006

Phase Distribution Of The Output Of Jaynes-Cummings Model With The Superposition Of Squeezed Displaced Fock States, Gamal Mohamed Abd Al-Kader

Turkish Journal of Physics

The Wigner quasi-probability function for the superposition of squeezed displaced Fock states (SDFS's) is reviewed. The interaction of these states with a two-level atom in cavity with the presence of additional Kerr medium is studied. Exact general matrix elements of the time-dependent operators of a Jaynes-Cummings model (JCM), in the presence of a Kerr medium, with these states are derived. We have obtained the phase distribution by two different ways: one is by Pegg-Barnett formalism, the second is by integration of the Wigner function over the radial variable. Results of these two approaches are compared. The Wigner phase distributions for …

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Modulated Photoconductivity Studies Of A-As_2se_3 Thin Films, Ruhi̇ Kaplan Jan 2006

Modulated Photoconductivity Studies Of A-As_2se_3 Thin Films, Ruhi̇ Kaplan

Turkish Journal of Physics

Modulated photocurrent measurements in amorphous arsenic triselenide (a-As_2Se_3) is reported. Particular focus is paid towards photocarrier lifetimes as a function of temperature, and applied electric field (i.e. dc) were determined by using the quadrature frequency-resolved spectroscopy method. The activation energy from the photocurrent as a function of temperature was determined to be about 125 meV for a constant illumination intensity of 2.3 mW. Its value was found to be almost independent of the applied electric field. The exponent \nu in the power law relationship (I_{ph} \propto G^v) between generating flux and photocurrent was obtained under different electric fields. The electric …

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Electrical Switching Behaviour In Lead Phosphovanadate Glasses, B. Sujatha, C. Narayana Reddy Jan 2006

Electrical Switching Behaviour In Lead Phosphovanadate Glasses, B. Sujatha, C. Narayana Reddy

Turkish Journal of Physics

Electrical switching behaviour of lead phosphovanadate glasses were studied by determining the current-voltage characteristics. All the investigated glasses exhibit the dependence of threshold voltages on temperature, thickness and composition. Below holding current the I - V characteristics obey Ohms law followed by a negative resistance region where the bulk behaviour dominates and at higher values of current the samples goes to a low resistance state. The studied glasses exhibit memory type switching. It is suggested that the initial switching and channel formation are due to electronic, while thermal effects dominate in the formation of channels.

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Plane Symmetric Solutions Of Gravitational Field Equations In Five Dimensions, A. N. Aliev, Hakan Cebeci̇, Teki̇n Dereli̇ Jan 2006

Plane Symmetric Solutions Of Gravitational Field Equations In Five Dimensions, A. N. Aliev, Hakan Cebeci̇, Teki̇n Dereli̇

Turkish Journal of Physics

We present the effective field equations obtained from a generalized gravity action with Euler-Poincaré term and a cosmological constant in a D dimensional bulk space-time. A class of plane-symmetric solutions that describe a 3-brane world embedded in a D=5 dimensional bulk space-time are given.

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Degenerate Spin Structures And The Lévy-Leblond Equation, Teki̇n Dereli̇, Şahi̇n Koçak, Murat Li̇moncu Jan 2006

Degenerate Spin Structures And The Lévy-Leblond Equation, Teki̇n Dereli̇, Şahi̇n Koçak, Murat Li̇moncu

Turkish Journal of Physics

Newton-Cartan manifolds and the Galilei group are defined by the use of co-rank one degenerate metric tensor. Newton-Cartan connection is lifted to the degenerate spinor bundle over a Newton-Cartan 4-manifold by the aid of degenerate spin group. Levy-Leblond equation is constructed with the lifted connection.

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Isopiestic Measurement Of The Osmotic Coefficients Of Aqueous {Xh2So4 + (1−X)Fe2(So4)3} Solutions At 298.15 And 323.15 K, Mariano Velazquez-Rivera, Donald Palmer, Richard Kettler Jan 2006

Isopiestic Measurement Of The Osmotic Coefficients Of Aqueous {Xh2So4 + (1−X)Fe2(So4)3} Solutions At 298.15 And 323.15 K, Mariano Velazquez-Rivera, Donald Palmer, Richard Kettler

Department of Earth and Atmospheric Sciences: Faculty Publications

This study measures the osmotic coefficients of {xH2SO4 +(1−x)Fe2 (SO4)3}(aq) solutions at 298.15 and 323.15 K that have ionic strengths as great as 19.3 mol•kg-1, using the isopiestic method. Experiments utilized both aqueous NaCl and H2SO4 as reference solutions. Equilibrium values of the osmotic coefficient obtained using the two different reference solutions were in satisfactory internal agreement. The solutions follow generally the Zdanovskii empirical linear relationship and yield values of aw for the Fe2 (SO4)3–H2O binary system at 298.15 …

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The Earth All Around Us: Selected Building Stone In Lincoln, Nebraska. A Walking Tour, William J. Wayne Jan 2006

The Earth All Around Us: Selected Building Stone In Lincoln, Nebraska. A Walking Tour, William J. Wayne

Department of Earth and Atmospheric Sciences: Faculty Publications

Stone has been a primary building material for millennia. Cities, therefore, are treasure troves of earth materials. A wide variety of stones from many places are used for walls, as foundations to support entire buildings, as trim, and more recently as cladding (facing, an overlay). The Earth science teacher can find, in the limited space of an urban environment, a superb collection of stones with which to introduce students to these materials. The surfaces of stones on the outsides of buildings illustrate the durability and the vulnerability of each kind of stone to the local climate. And the history of …

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Some General Notions Of Stochastic Orderings For Weighted Reliability And Uncertainty Measures With Applications, Broderick O. Oluyede Jan 2006

Some General Notions Of Stochastic Orderings For Weighted Reliability And Uncertainty Measures With Applications, Broderick O. Oluyede

Department of Mathematical Sciences Faculty Publications

In this note, stochastic comparisons of reliability measures and related functions are presented. Inequalities for uncertainty of a residual life distribution and certain modified cross-entropy or discrimination information measures under weighted models are established. Comparisons of the expected uncertainty about the remaining lifetime of a component for weighted conditional distributions and unweighted conditional distributions are presented.

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Multinational Web Uses And Gratifications: Measuring The Social Impact Of Online Community Participation Across National Boundaries, Patricia Grace-Farfaglia, Ad Dekkers, Binod Sundararajan, Lois Peters, Sung-Hee Park Jan 2006

Multinational Web Uses And Gratifications: Measuring The Social Impact Of Online Community Participation Across National Boundaries, Patricia Grace-Farfaglia, Ad Dekkers, Binod Sundararajan, Lois Peters, Sung-Hee Park

Nutrition Sciences Faculty Publications

This paper describes the rationale and findings from a multinational study of online uses and gratifications conducted in theUnited States,Korea, and theNetherlandsin spring 2003. Survey questions developed in three languages by native speaking researchers was presented to approximately 400 respondents in each country via the Web. Web uses and gratifications were analyzed cross-nationally in a comparative fashion focusing on involvement in different types of on-line communities. Findings indicate that demographic characteristics, cultural values, and Internet connection type emerged as critical factors that explain why the same technology is adopted differently.

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Monte Carlo Random Walk Simulations Based On Distributed Order Differential Equations With Applications In Cell Biology, Erik Andries, Sabir Umarov, Stanly Steinberg Jan 2006

Monte Carlo Random Walk Simulations Based On Distributed Order Differential Equations With Applications In Cell Biology, Erik Andries, Sabir Umarov, Stanly Steinberg

Mathematics Faculty Publications

In this paper the multi-dimensional random walk models governed by distributed fractional order differential equations and multi-term fractional order differential equations are constructed. The scaling limits of these random walks to a diffusion process in the sense of distributions is proved. Simulations based upon multi-term fractional order differential equations are performed.

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Leading Hackers Down The Garden Path, Suen Yek Jan 2006

Leading Hackers Down The Garden Path, Suen Yek

Research outputs pre 2011

Can a hacker be controlled by predetermined deception? Limiting the decision making capabilities of hackers is one technique of network countermeasure that a honeynet enables. By furnishing a honeynet with a realistic range of services but restricted vulnerabilities, a hacker may be forced to direct their attacks to the only available exploits. This research discusses the deployment of a honeynet configured with a deceptive TELNET and TFTP exploit. Four hackers were invited to attack the honeynet and the analysis of their compromise identified if they engaged in a guided pathway to the intended deception. Hand trace analysis was performed on …

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Improving Community Water Conservation Behaviour In Chachoengsao, Thailand, Kuakul Sathapornvajana, Lynne Cohen, Neil Drew, Julie Ann Pooley Jan 2006

Improving Community Water Conservation Behaviour In Chachoengsao, Thailand, Kuakul Sathapornvajana, Lynne Cohen, Neil Drew, Julie Ann Pooley

EDU-COM International Conference

The issue of water supply throughout the world is of concern for many reasons. A major factor is water pollution by industry, agriculture and residential sectors. Less than 3% of water is fresh and potable, while the remainder is saline. It is projected that by the year 2025, two-thirds of the world‘s population will encounter moderate to severe water shortages. As a result of unsustainable development over the past decade, Thailand has faced pollution problems as well as the depletion of many natural resources. These problems have impacted the country‘s main rivers (Chaopraya River, Thachine River, and the Bangpakong River), …

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Temporal And Vertical Dynamics In Picoplankton Photoheterotrophic Production In The Subtropical North Pacific Ocean, M. J. Church, H. W. Ducklow, Et Al Jan 2006

Temporal And Vertical Dynamics In Picoplankton Photoheterotrophic Production In The Subtropical North Pacific Ocean, M. J. Church, H. W. Ducklow, Et Al

VIMS Articles

Heterotrophic microbial production is a fundamental determinant in the flow of bioelements and energy within the pelagic ecosystems of the open ocean. To characterize the temporal dynamics in rates of heterotrophic picoplankton production (HPP), we examined vertical profiles of H-3-leucine (H-3-leu) and [methyl-H-3]-thymidine (H-3-TdR) incorporation at Stn ALOHA (22 degrees 45'N, 158 degrees W) in the oligotrophic North Pacific Ocean. Euphotic zone rates of H-3-leu and H-3-TdR incorporation were measured in situ under light and dark conditions on cruises to Stn ALOHA between April 2000 and August 2005. Rates of H-3-leu and H-3-TdR incorporation were elevated in the well-lit upper …

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Synthesis And Analysis Of An Α-Amylase Inhibitor And An Antimicrobial Peptide, Brahmlin Kaur Sethi Jan 2006

Synthesis And Analysis Of An Α-Amylase Inhibitor And An Antimicrobial Peptide, Brahmlin Kaur Sethi

Senior Honors Theses and Projects

Abstract 1: α-Amylase is an important enzyme in the body responsible for hydrolyzing many polysaccharides such as dietary starch. Inhibition of this enzyme could be extremely beneficial in diabetic patients because it could lower the glucose levels in the blood. Our objective is to synthesize a small analog of a natural α-amylase inhibitor, Tendamistat. This molecule has 15-22 residue segment that are critical for its activity. The peptide was synthesized, cleaved, purified, analyzed, and an enzyme assay was run. Michaelis Menton and Lineweaver-Burk plots were constructed to determine the Vmax, Km, and Ki for each …

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A Taxonomy Of Teleology: Phillip Johnson, The Intelligent Design Community, And Young-Earth Creationism, Marcus R. Ross, P. A. Nelson Jan 2006

A Taxonomy Of Teleology: Phillip Johnson, The Intelligent Design Community, And Young-Earth Creationism, Marcus R. Ross, P. A. Nelson

Faculty Publications and Presentations

No abstract provided.

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A Proposed Architecture For The Geni Backbone Platform, Jonathan Turner Jan 2006

A Proposed Architecture For The Geni Backbone Platform, Jonathan Turner

All Computer Science and Engineering Research

The GENI Project (Global Environment for Network Innovation) is a major NSF-sponsored initiative that seeks to create a national research facility to enable experimental deployment of innovative new network architectures on a sufficient scale to enable realistic evaluation. One key component of the GENI system will be the GENI Backbone Platform (GBP) that provides the resources needed to allow multiple experimental networks to co-exist within the shared GENI infrastructure. This report reviews the objectives for the GBP, reviews the key issues that affect its design and develops a detailed reference architecture in order to provide a concrete example for how …

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Feature Detection Using Curvature Maps And The Min-Cut/Max-Flow Graph Cut Algorithm, Timothy Gatzke, Cindy Grimm Jan 2006

Feature Detection Using Curvature Maps And The Min-Cut/Max-Flow Graph Cut Algorithm, Timothy Gatzke, Cindy Grimm

All Computer Science and Engineering Research

Automatic detection of features in three-dimensional objects is a critical part of shape matching tasks such as object registration and recognition. Previous approaches to local surface matching have either focused on man-made objects, where features are generally well-defined, or required some type of user interaction to select features. Manual selection of corresponding features and subjective determination of the difference between objects are time consuming processes requiring a high level of expertise. Curvature is a useful property of a surface, but curvature calculation on a discrete mesh is often noisy and not always accurate. However, the em Curvature Map, which represents …

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Acceleration Of Gapped Alignment In Blastp Using The Mercury System, Brandon B. Harris Jan 2006

Acceleration Of Gapped Alignment In Blastp Using The Mercury System, Brandon B. Harris

All Computer Science and Engineering Research

Protein databases have grown exponentially over the last decade. This exponential growth has made extracting valuable information from these databases increasingly time consuming. This project presents a new method of accelerating a commonly used program for performing similarity searching on protein databases, BLASTP. This project describes the design and implementation of Mercury BLASTP, a customized hardware accelerated variant of BLASTP. This project focuses on the gapped alignment stage of Mercury BLASTP and provides design details and implementation results.

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Mixed-Integer Linear Programming Solution To Multi-Robot Task Allocation Problem, Nuzhet Atay, Burchan Bayazit Jan 2006

Mixed-Integer Linear Programming Solution To Multi-Robot Task Allocation Problem, Nuzhet Atay, Burchan Bayazit

All Computer Science and Engineering Research

Multi-robot systems require efficient and accurate planning in order to perform mission-critical tasks. This paper introduces a mixed-integer linear programming solution to coordinate multiple heterogenenous robots for detecting and controlling multiple regions of interest in an unknown environment. The objective function contains four basic requirements of a multi-robot system serving this purpose: control regions of interest, provide communication between robots, control maximum area and detect regions of interest. Our solution defines optimum locations of robots in order to maximize the objective function while efficiently satisfying some constraints such as avoiding obstacles and staying within the speed capabilities of the robots. …

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Prairie Wetlands And Climate Change - Droughts And Ducks On The Prairies, Glenn R. Guntenspergen, W.Carter Johnson, David E. Naugle Jan 2006

Prairie Wetlands And Climate Change - Droughts And Ducks On The Prairies, Glenn R. Guntenspergen, W.Carter Johnson, David E. Naugle

Natural Resource Management Faculty Publications

The Prairie Pothole Region (PPR) contains 5-8 million small wetlands and is one of the most ecologically valuable freshwater resources of the Nation. These wetlands provide abundant ecosystem services, including groundwater recharge, water for agriculture, water purification, and recreation. The PPR is best known as the “duck factory” of North America. By some estimates, this region produces over 50% of the ducks in North America.

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Nebraska Cooperative Fish And Wildlife Research Unit: Report Of Activities July 2004 – October 2006 Jan 2006

Nebraska Cooperative Fish And Wildlife Research Unit: Report Of Activities July 2004 – October 2006

Nebraska Cooperative Fish and Wildlife Research Unit: Annual Reports

Contents
Personnel and Cooperators . 1
Coordinating Committee Members. 1
Nebraska Cooperative Fish and Wildlife Research Unit Staff . 1
University of Nebraska–Lincoln Faculty Cooperators. 2
Nebraska Game and Parks Commission Cooperators. 2
Federal Agency Cooperators . 2
State Agency Cooperators . 2
Private Sector Cooperators . 3
Other Faculty Cooperators . 3
Graduate Degree Candidates . 3
Post-Doctoral Research Associates . 4
Research Technicians. 4
Federal Work-Study Students . 4
Other Cooperative Unit Staff . 4
Projects in Fisheries Science. 5
Projects in Wildlife Science. 11
Teaching . 23
Training and Workshops . 25
Professional Activities. 27
Peer-Reviewed Publications …

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Search For Scalar Leptoquarks In The Acoplanar Jet Topology In Pp Collisions At √ S = 1.96 Tev, V. M. Abazov, Kenneth A. Bloom, Gregory Snow, D0 Collaboration Jan 2006

Search For Scalar Leptoquarks In The Acoplanar Jet Topology In Pp Collisions At √ S = 1.96 Tev, V. M. Abazov, Kenneth A. Bloom, Gregory Snow, D0 Collaboration

Kenneth Bloom Publications

A search for leptoquarks has been performed in 310 pb−1 of data from pp collisions at a center-of-mass energy of 1.96 TeV, collected by the D0 detector at the Fermilab Tevatron Collider. The topology analyzed consists of acoplanar jets with missing transverse energy. The data show good agreement with standard model expectations, and a lower mass limit of 136 GeV has been set at the 95% C.L. for a scalar leptoquark decaying exclusively into a quark and a neutrino.

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Efficient Scheduling For Sdmg Cioq Switches, Mei Yang, S. Q. Zheng Jan 2006

Efficient Scheduling For Sdmg Cioq Switches, Mei Yang, S. Q. Zheng

Electrical & Computer Engineering Faculty Research

Combined input and output queuing (CIOQ) switches are being considered as high-performance switch architectures due to their ability to achieve 100% throughput and perfectly emulate output queuing (OQ) switch performance with a small speedup factor S. To realize a speedup factor S, a conventional CIOQ switch requires the switching fabric and memories to operate S times faster than the line rate. In this paper, we propose to use a CIOQ switch with space-division multiplexing expansion and grouped input/output ports (SDMG CIOQ switch for short) to realize speedup while only requiring the switching fabric and memories to operate at the line …

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Multiple Hypotheses Testing Of Fish Incidence Patterns In An Urbanized Ecosystem, Christopher J. Chizinski, C.L. Higgins, C.E. Shavlik, Kevin L. Pope Jan 2006

Multiple Hypotheses Testing Of Fish Incidence Patterns In An Urbanized Ecosystem, Christopher J. Chizinski, C.L. Higgins, C.E. Shavlik, Kevin L. Pope

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Ecological and evolutionary theories have focused traditionally on natural processes with little attempt to incorporate anthropogenic influences despite the fact that humans are such an integral part of virtually all ecosystems. A series of alternate models that incorporated anthropogenic factors and traditional ecological mechanisms of invasion to account for fish incidence patterns in urban lakes was tested. The models were based on fish biology, human intervention, and habitat characteristics. However, the only models to account for empirical patterns were those that included fish invasiveness, which incorporated speciesspecific information about overall tolerance and fecundity. This suggests that species-specific characteristics are more …

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Temperature-Caused Fish Kill In A Flowing Great Plains River, Bart W. Durham, Gene R. Wilde, Kevin L. Pope Jan 2006

Temperature-Caused Fish Kill In A Flowing Great Plains River, Bart W. Durham, Gene R. Wilde, Kevin L. Pope

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

On 9 July 2002, while sampling a flowing segment of the North Fork Ninnescah River 10 km upstream from Cheney Reservoir, Reno County, Kansas, we observed and collected dead and dying specimens of 5 fish species. We attribute the fish kill to high water temperature, which reached 38.0°C on this day.

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A Framework For Spatial Risk Assessments: Potential Impacts Of Nonindigenous Invasive Species On Native Species, Craig R. Allen, Alan R, Johnson, Leslie Parris Jan 2006

A Framework For Spatial Risk Assessments: Potential Impacts Of Nonindigenous Invasive Species On Native Species, Craig R. Allen, Alan R, Johnson, Leslie Parris

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Many populations of wild animals and plants are declining and face increasing threats from habitat fragmentation and loss as well as exposure to stressors ranging from toxicants to diseases to invasive nonindigenous species. We describe and demonstrate a spatially explicit ecological risk assessment that allows for the incorporation of a broad array of information that may influence the distribution of an invasive species, toxicants, or other stressors, and the incorporation of landscape variables that may influence the spread of a species or substances. The first step in our analyses is to develop species models and quantify spatial overlap between stressor …

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Predictors Of Introduction Success In The South Florida Avifauna, Craig R. Allen Jan 2006

Predictors Of Introduction Success In The South Florida Avifauna, Craig R. Allen

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Biological invasions are an increasing global challenge, for which single-species studies and analyses focused on testing single hypotheses of causation in isolation are unlikely to provide much additional insight. Species interact with other species to create communities, which derive from species interactions and from the interactions of species with the scale specific elements of the landscape that provide suitable habitat and exploitable resources. I used logistic regression analysis to sort among potential intrinsic, community and landscape variables that theoretically influence introduction success. I utilized the avian fauna of the Everglades of South Florida, and the variables body mass, distance to …

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Habitat Selection Responses Of Parents To Offspring Predation Risk: An Experimental Test, J. J. Fontaine, T. E. Martin Jan 2006

Habitat Selection Responses Of Parents To Offspring Predation Risk: An Experimental Test, J. J. Fontaine, T. E. Martin

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

The ability of nest predation to influence habitat settlement decisions in birds is widely debated, despite its importance in limiting fitness. Here, we experimentally manipulated nest predation risk across a landscape and asked the question, do migratory birds assess and respond to variation in nest predation risk when choosing breeding habitats? We examined habitat preference by quantifying the density and settlement date of eight species of migratory passerines breeding in areas with and without intact nest predator communities. We found consistently more individuals nesting in areas with reduced nest predation than in areas with intact predator assemblages, although predation risk …

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