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2009

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Articles 541 - 557 of 557

Full-Text Articles in Physical Sciences and Mathematics

An Inventory And Condition Survey Of The Lower Murchison River Area, Western Australia, P Hennig Jan 2009

An Inventory And Condition Survey Of The Lower Murchison River Area, Western Australia, P Hennig

Technical Bulletins

The inventory and condition survey of the lower Murchison River area, undertaken by the Department of Agriculture and Food, Western Australia (DAFWA) between 2002 and 2003, describes and maps the natural resources of the region’s pastoral leasehold land. This survey report provides a baseline record of the existence and condition of the natural area’s resources, to assist with the planning and implementation of land management practices. The report identified and described the condition of soils, landforms, vegetation, habitat, ecosystems, and declared plants and animals. It also assessed the impact of pastoralism and made land management recommendations. This survey report presents …

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Farmers And Nature Conservation: What Is Known About Attitudes, Context Factors And Actions Affecting Conservation?, Johan Ahnström, Jenny Höckert, Hanna L. Bergea, Charles A. Francis, Peter Skelton, Lars Hallgren Jan 2009

Farmers And Nature Conservation: What Is Known About Attitudes, Context Factors And Actions Affecting Conservation?, Johan Ahnström, Jenny Höckert, Hanna L. Bergea, Charles A. Francis, Peter Skelton, Lars Hallgren

Department of Agronomy and Horticulture: Faculty Publications

Farmers’ attitudes towards viability of specific conservation practices or actions strongly impact their decisions on adoption and change. This review of ‘attitude’ information reveals a wide range of perceptions about what conservation means and what the impacts of adoption will mean in economic and environmental terms. Farmers operate in a tight financial situation, and in parts of the world they are highly dependent on government subsidies, and cannot afford to risk losing that support. Use of conservation practices is most effective when these are understood in the context of the individual farm, and decisions are rooted in land and resource …

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Farming Systems Education: Case Study Of Swedish Test Pilots, Lennart Salomonsson, Anna Nilsson, Sofia Palmer, Adam Roigart, Charles A. Francis Jan 2009

Farming Systems Education: Case Study Of Swedish Test Pilots, Lennart Salomonsson, Anna Nilsson, Sofia Palmer, Adam Roigart, Charles A. Francis

Department of Agronomy and Horticulture: Faculty Publications

We describe and analyze a pedagogical experiment that introduced a broad and holistic perspective on complete farming systems, systemic learning tools, and a participatory learning strategy at an early stage in agronomy education. The paper describes the adventure of three students, who came from a conventional agronomy program at the Swedish University of Agricultural Sciences (SLU), who were frustrated with the lack of integrated approaches to the study of agricultural systems and a strong focus on molecular-level processes in their first year of education. They encountered a narrow focus in most courses and the overall curricula of agricultural education that …

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Distribution Of Calcifying And Silicifying Phytoplankton In Relation To Environmental And Biogeochemical Parameters During The Late Stages Of The 2005 North East Atlantic Spring Bloom, K. Leblanc, C.E. Hare, Y. Feng, G.M. Berg, G.R. Ditullio, A. Neeley, I. Benner, C. Sprengel, A. Beck, S.A. Sanudo-Wilhemy, U. Passow, K. Klinck, J.M. Rowe, Steven Wilhelm, C.W. Brown, D.A. Hutchins Jan 2009

Distribution Of Calcifying And Silicifying Phytoplankton In Relation To Environmental And Biogeochemical Parameters During The Late Stages Of The 2005 North East Atlantic Spring Bloom, K. Leblanc, C.E. Hare, Y. Feng, G.M. Berg, G.R. Ditullio, A. Neeley, I. Benner, C. Sprengel, A. Beck, S.A. Sanudo-Wilhemy, U. Passow, K. Klinck, J.M. Rowe, Steven Wilhelm, C.W. Brown, D.A. Hutchins

Microbiology Publications and Other Works

The late stage of the North East Atlantic (NEA) spring bloom was investigated during June 2005 along a transect section from 45 to 66° N between 15 and 20° W in order to characterize the contribution of siliceous and calcareous phytoplankton groups and describe their distribution in relation to environmental factors. We measured several biogeochemical parameters such as nutrients, surface trace metals, algal pigments, biogenic silica (BSi), particulate inorganic carbon (PIC) or calcium carbonate, particulate organic carbon, nitrogen and phosphorus (POC, PON and POP, respectively), as well as transparent exopolymer particles (TEP). Results were compared with other studies undertaken in …

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The Effects Of Increased Pco2 And Temperature On The North Atlantic Spring Bloom: I. The Phytoplankton Community And Biogeochemical Response, Y. Feng, C.E. Hare, K. Leblanc, J.M. Rose, Y Zhang, G.R. Ditullio, P. Lee, Steven Wilhelm, J.M. Rowe, J. Sun, N. Nemcek, C. Gueguen, U. Passow, I. Benner, C. Brown, D.A. Hutchins Jan 2009

The Effects Of Increased Pco2 And Temperature On The North Atlantic Spring Bloom: I. The Phytoplankton Community And Biogeochemical Response, Y. Feng, C.E. Hare, K. Leblanc, J.M. Rose, Y Zhang, G.R. Ditullio, P. Lee, Steven Wilhelm, J.M. Rowe, J. Sun, N. Nemcek, C. Gueguen, U. Passow, I. Benner, C. Brown, D.A. Hutchins

Microbiology Publications and Other Works

ABSTRACT: The North Atlantic spring bloom is one of the largest annual biological events in the ocean, and is characterized by dominance transitions from siliceous (diatoms) to calcareous (coccolithophores) algal groups. To study the effects of future global change on these phytoplankton and the biogeochemical cycles they mediate, a shipboard continuous culture experiment (Ecostat) was conducted in June 2005 during this transition period. Four treatments were examined: (1) 12°C and 390 ppm CO2 (ambient control), (2) 12°C and 690 ppm CO2 (high pCO2), (3) 16°C and 390 ppm CO2 (high temperature), and (4) 16°C and …

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Actinorhodopsin Genes Discovered Diverse In Freshwater Habitats And Among Cultivated Actinobacteria, A.K. Sharma, K. Sommerfeld, G.S. Bullerjahn, A.R. Matteson, Steven Wilhelm, J. Jezbera, U. Brandt, W.F. Doolittle, M.W. Hahn Jan 2009

Actinorhodopsin Genes Discovered Diverse In Freshwater Habitats And Among Cultivated Actinobacteria, A.K. Sharma, K. Sommerfeld, G.S. Bullerjahn, A.R. Matteson, Steven Wilhelm, J. Jezbera, U. Brandt, W.F. Doolittle, M.W. Hahn

Microbiology Publications and Other Works

Microbial rhodopsins are membrane proteins that utilize a retinal chromophore to harvest sunlight for energetic and photosensory functions. Recently, a group of novel rhodopsin sequences named ‘actinorhodopsins’ (ActRs) was hypothesized to exist among uncultured planktonic Actinobacteria. ActRs were discovered by mining metagenomic data obtained during the Venter Institute’s Global Ocean Sampling expedition, from a hypersaline lagoon, two estuaries and a freshwater lake. On the basis of these findings, and many studies that show Actinobacteria are common inhabitants of lakes, we predicted that ActR genes would likely be present in other freshwater habitats and among the genomes of cultivated Actinobacteria …

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Ecosystems Services Of Tidal Shorelines, Center For Coastal Resources Management, Virginia Institute Of Marine Science Jan 2009

Ecosystems Services Of Tidal Shorelines, Center For Coastal Resources Management, Virginia Institute Of Marine Science

Reports

Rivers & Coast is a periodic publication of the Center for Coastal Resources Management, Virginia Institute of Marine Science. The goal of Rivers & Coast is to keep readers well informed of current scientific understanding behind key environmental issues related to watershed rivers and coastal ecosystems of the Chesapeake Bay.

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Climate Change And Submerged Aquatic Vegetation In Virginia, Kenneth A. Moore, Robert J. Orth, Virginia Institute Of Marine Science. Initiative For Coastal Climate Change Research Jan 2009

Climate Change And Submerged Aquatic Vegetation In Virginia, Kenneth A. Moore, Robert J. Orth, Virginia Institute Of Marine Science. Initiative For Coastal Climate Change Research

Reports

VIMS climate change white paper: Climate change and submerged aquatic vegetation in Virginia

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Planning For Sea Level Rise And Coastal Flooding, John D. Boon, Harry V. Wang, Jian Shen, Virginia Institute Of Marine Science. Initiative For Coastal Climate Change Research Jan 2009

Planning For Sea Level Rise And Coastal Flooding, John D. Boon, Harry V. Wang, Jian Shen, Virginia Institute Of Marine Science. Initiative For Coastal Climate Change Research

Reports

VIMS climate change white papers: Planning for sea level rise and coastal flooding

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Extreme Storm Events Increase The Risk For Chemical Contamination Of Coastal Waters, Michael A. Unger, Virginia Institute Of Marine Science. Initiative For Coastal Climate Change Research Jan 2009

Extreme Storm Events Increase The Risk For Chemical Contamination Of Coastal Waters, Michael A. Unger, Virginia Institute Of Marine Science. Initiative For Coastal Climate Change Research

Reports

Sea-level rise and an increase in the severity of coastal storms are probable outcomes for the Chesapeake Bay due to global climate change. A consequent ecological and economic risk for tidewater Virginia and other low-lying coastal zones is the contamination of coastal waters by industrial and agricultural chemicals released by accidental spills during severe storm events. . . .

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Land-Coast Connections And Climate Change : Carbon Cycling In Chesapeake Bay And Its Watershed, Elizabeth A. Canuel, James E. Bauer, Virginia Institute Of Marine Science, Initiative For Coastal Climate Change Research Jan 2009

Land-Coast Connections And Climate Change : Carbon Cycling In Chesapeake Bay And Its Watershed, Elizabeth A. Canuel, James E. Bauer, Virginia Institute Of Marine Science, Initiative For Coastal Climate Change Research

Reports

VIMS climate change white paper: Land-coast connections and climate change : carbon cycling in Chesapeake Bay and its watershed

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Vanishing And Emerging Ecosystems Of Coastal Virginia : Climate Change Impacts And Adaptation, Emmett J. Duffy, Virginia Institute Of Marine Science. Initiative For Coastal Climate Change Research Jan 2009

Vanishing And Emerging Ecosystems Of Coastal Virginia : Climate Change Impacts And Adaptation, Emmett J. Duffy, Virginia Institute Of Marine Science. Initiative For Coastal Climate Change Research

Reports

VIMS climate change white papers: Vanishing and emerging ecosystems of coastal Virginia : climate change impacts and adaptation

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Climate Change And Aquatic Animal Health In Virginia : Effects And Responses, Wolfgang K. Vogelbein, Eugene M. Burreson, Ryan Carnegie, Jeffrey D. Shields, Virginia Institute Of Marine Science. Initiative For Coastal Climate Change Reseach Jan 2009

Climate Change And Aquatic Animal Health In Virginia : Effects And Responses, Wolfgang K. Vogelbein, Eugene M. Burreson, Ryan Carnegie, Jeffrey D. Shields, Virginia Institute Of Marine Science. Initiative For Coastal Climate Change Reseach

Reports

Climate change, with concomitant increases in sea level, temperature, greenhouse gases and alterations in precipitation, is a major environmental challenge for the future management of Virginia’s valuable marine resources.

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Potential Export Of Unattached Benthic Macroalgae To The Deep Sea Through Wind Driven Langmuir Circulation, H. M. Dierssen, Richard C. Zimmerman, Lisa A. Drake, David J. Burdige Jan 2009

Potential Export Of Unattached Benthic Macroalgae To The Deep Sea Through Wind Driven Langmuir Circulation, H. M. Dierssen, Richard C. Zimmerman, Lisa A. Drake, David J. Burdige

OES Faculty Publications

Carbon export to the deep sea is conventionally attributed to the sinking of open ocean phytoplankton. Here, we report a Langmuir supercell event driven by high winds across the shallow Great Bahama Bank that organized benthic non-attached macroalgae, Colpomenia sp., into visible windrows on the seafloor. Ocean color satellite imagery obtained before and after the windrows revealed a 588 km2 patch that rapidly shifted from highly productive macroalgae to bare sand. We assess a number of possible fates for this macroalgae and contend that this event potentially transported negatively buoyant macroalgae to the deep Tongue of the Ocean …

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Spatial Variation In Otolith Chemistry Of Atlantic Croaker Larvae In The Mid-Atlantic Bight, Jason J. Schaffler, Christian S. Reiss, Cynthia M. Jones Jan 2009

Spatial Variation In Otolith Chemistry Of Atlantic Croaker Larvae In The Mid-Atlantic Bight, Jason J. Schaffler, Christian S. Reiss, Cynthia M. Jones

OES Faculty Publications

Larval Atlantic croaker Micropogonias undulatus (1 to 7 mm in standard length) were collected on the east coast of the United States from North Carolina to Delaware during 2000. We defined 3 water-mass boundaries for potential groups of spawning Atlantic croaker using temperature and salinity measured at each sampling station. We tested the hypothesis that distinct otolith chemistries existed among 3 groups of larval Atlantic croaker collected from these water masses using solution-based inductively coupled plasma-mass spectrometry. Multivariate analysis of variance indicated that otolith chemistry differed significantly among water masses. Using a quadratic discriminant function, we were able to correctly …

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Synergistic Effects Of Iron And Temperature On Antarctic Phytoplankton And Microzooplankton Assemblages, J. M. Rose, Y. Feng, G. R. Ditullio, R. B. Dunbar, C. E. Hare, P. A. Lee, M. Lohan, M. Long, W. O. Smith Jr., B. Sohst, S. Tozzi, Y. Zhang, D. A. Hutchins Jan 2009

Synergistic Effects Of Iron And Temperature On Antarctic Phytoplankton And Microzooplankton Assemblages, J. M. Rose, Y. Feng, G. R. Ditullio, R. B. Dunbar, C. E. Hare, P. A. Lee, M. Lohan, M. Long, W. O. Smith Jr., B. Sohst, S. Tozzi, Y. Zhang, D. A. Hutchins

OES Faculty Publications

Iron availability and temperature are important limiting factors for the biota in many areas of the world ocean, and both have been predicted to change in future climate scenarios. However, the impacts of combined changes in these two key factors on microbial trophic dynamics and nutrient cycling are unknown. We examined the relative effects of iron addition (+1 nM) and increased temperature (+4° C) on plankton assemblages of the Ross Sea, Antarctica, a region characterized by annual algal blooms and an active microbial community. Increased iron and temperature individually had consistently significant but relatively minor positive effects on total phytoplankton …

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Multiple Imputation To Correct For Measurement Error In Admixture Estimates In Genetic Structured Association Testing, Miguel A. Padilla, Jamin Divers, Laura K. Vaughan, David B. Allison, Hemant K. Tiwari Jan 2009

Multiple Imputation To Correct For Measurement Error In Admixture Estimates In Genetic Structured Association Testing, Miguel A. Padilla, Jamin Divers, Laura K. Vaughan, David B. Allison, Hemant K. Tiwari

Psychology Faculty Publications

Objectives: Structured association tests ( SAT), like any statistical model, assumes that all variables are measured without error. Measurement error can bias parameter estimates and confound residual variance in linear models. It has been shown that admixture estimates can be contaminated with measurement error causing SAT models to suffer from the same afflictions. Multiple imputation (MI) is presented as a viable tool for correcting measurement error problems in SAT linear models with emphasis on correcting measurement error contaminated admixture estimates. Methods: Several MI methods are presented and compared, via simulation, in terms of controlling Type I error rates for both …

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