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Articles 1171 - 1200 of 1654

Full-Text Articles in Other Earth Sciences

Relatin Dissolved Oxygen Concentration To Fish Distribution In Jarecki Lake, Adam Sutton Apr 2010

Relatin Dissolved Oxygen Concentration To Fish Distribution In Jarecki Lake, Adam Sutton

Department of Environmental Studies: Undergraduate Student Theses

Abstract Water temperature and dissolved oxygen (DO) profiles were measured once every month from mid July to mid February in a relatively deep sand-pit lake in southeast Nebraska. These profiles showed depleted DO concentrations below the thermocline during summer stratification indicating areas fish will likely avoid in summer months. Colder temperatures in fall caused complete mixing of the water column allowing fish to inhabit all depths of the lake. An inverse temperature stratification occurred directly below the ice during winter months as ice cover cooled the surface water to below 4 degrees Celsius. Ice cover also blocked air – water …


Effects Of Drought On Avian Community Structure, Thomas P. Albright, Anna M. Pidgeon, Chadwick D. Rittenhouse, Murray K. Clayton, Curtis H. Flather, Patrick D. Culbert, Brian D. Wardlows, Volker C. Radeloff Jan 2010

Effects Of Drought On Avian Community Structure, Thomas P. Albright, Anna M. Pidgeon, Chadwick D. Rittenhouse, Murray K. Clayton, Curtis H. Flather, Patrick D. Culbert, Brian D. Wardlows, Volker C. Radeloff

National Drought Mitigation Center: Faculty Publications

Droughts are expected to become more frequent under global climate change. Avifauna depend on precipitation for hydration, cover, and food. While there are indications that avian communities respond negatively to drought, little is known about the response of birds with differing functional and behavioral traits, what time periods and indicators of drought are most relevant, or how response varies geographically at broad spatial scales. Our goals were thus to determine (1) how avian abundance and species richness are related to drought, (2) whether community variations are more related to vegetation vigor or precipitation deviations and at what time periods relationships …


Regional Vs. Local Impact Of Wind On Glaciers In The Andes Mountains, Derek Ferris Jan 2010

Regional Vs. Local Impact Of Wind On Glaciers In The Andes Mountains, Derek Ferris

Undergraduate Review

Northern Peru will face critical water resource issues in the near future as permanent ice in the Andes Mountains continues to rapidly melt. Ironically, the melt-water from these glaciers supports the culture of 100s of thousands of people living at lower elevations, particularly during the dry season, and predictions suggest some glaciers may be gone in less than 100 years. The impact of local warming of “U” shaped valleys running down the dryer western slope of the Andes range is largely disregarded in current climate model predictions because of the complexity of simulating the complex topography. Studies that compare the …


Correlation Between Normalized Ddifference Vvegetation Index And Malaria In A Subtropical Rain Forest Undergoing Rapid Anthropogenic Alteration, Nicole M. Wayant, Diego Maldonado, Antonieta Rojas De Arias, Blanca Cousino, Douglas G. Goodin Jan 2010

Correlation Between Normalized Ddifference Vvegetation Index And Malaria In A Subtropical Rain Forest Undergoing Rapid Anthropogenic Alteration, Nicole M. Wayant, Diego Maldonado, Antonieta Rojas De Arias, Blanca Cousino, Douglas G. Goodin

Center for Advanced Land Management Information Technologies: Publications

Time-series of coarse-resolution greenness values derived through remote sensing have been used as a surrogate environmental variable to help monitor and predict occurrences of a number of vector-borne and zoonotic diseases, including malaria. Often, relationships between a remotely-sensed index of greenness, e.g. the normalized difference vegetation index (NDVI), and disease occurrence are established using temporal correlation analysis. However, the strength of these correlations can vary depending on type and change of land cover during the period of record as well as inter-annual variations in the climate drivers (precipitation, temperature) that control the NDVI values. In this paper, the correlation between …


Geochemical And Mineralogical Evidence For Sahara And Sahel Dust Additions To Quaternary Soils On Lanzarote, Eastern Canary Islands, Spain, Daniel R. Muhs, James Budahn, Gary Skipp, Joseph M. Prospero, Deanna Patterson, E. Arthur Bettis Iii Jan 2010

Geochemical And Mineralogical Evidence For Sahara And Sahel Dust Additions To Quaternary Soils On Lanzarote, Eastern Canary Islands, Spain, Daniel R. Muhs, James Budahn, Gary Skipp, Joseph M. Prospero, Deanna Patterson, E. Arthur Bettis Iii

United States Geological Survey: Staff Publications

Africa is the most important source of dust in the world today, and dust storms are frequent on the nearby Canary Islands. Previous workers have inferred that the Sahara is the most important source of dust to Canary Islands soils, with little contribution from the Sahel region. Soils overlying a late Quaternary basalt flow on Lanzarote, Canary Islands, contain, in addition to volcanic minerals, quartz and mica, exotic to the island!s bedrock. Kaolinite in the soils also likely has an exotic origin. Trace-element geochemistry shows that the soils are derived from varying proportions of locally derived basalt and African dust. …


Development And Application Of A Pollen-Based Paleohydrologic Reconstruction From The Lower Roanoke River Basin, North Carolina, Usa, Debra Willard, Christopher Bernhardt, Roger Brown, Bryan Landacre, Philip A. Townsend Jan 2010

Development And Application Of A Pollen-Based Paleohydrologic Reconstruction From The Lower Roanoke River Basin, North Carolina, Usa, Debra Willard, Christopher Bernhardt, Roger Brown, Bryan Landacre, Philip A. Townsend

United States Geological Survey: Staff Publications

We used pollen assemblages to reconstruct late-Holocene paleohydrologic patterns in floodplain deposits from the lower Roanoke River basin (North Carolina, southeastern USA). Using 120 surface samples from 38 transects, we documented statistical relationships between pollen assemblages, vegetation, and landforms. Backswamp pollen assemblages (long hydroperiods) are dominated by Nyssa (tupelo) and Taxodium (cypress) and have high pollen concentrations. Sediments from elevated levees and seasonally flooded forests (shorter hydroperiods) are characterized by dominant Pinus (pine) pollen, variable abundance of hardwood taxa, and low pollen concentrations. We apply the calibration data set to interpret past vegetation and paleohydrology. Pollen from a radiocarbon-dated sediment …


Droughtscape, Winter 2010, Kelly Smith Jan 2010

Droughtscape, Winter 2010, Kelly Smith

DroughtScape: Quarterly Newsletter of the National Drought Mitigation Center (2007–2023)

USDM Forum Highlights

Drought Likely to Ease

Research Shows Birds Vulnerable to Drought

Drought Recedes in 2009

CA, TX Suffer Impacts from Ongoing Drought

NDMC Wishes Ryu Well

Conferees Pick SPI for Global Drought Index


Absorption And Biotransformation Of Polybrominated Diphenyl Ethers De-71 And De-79 In Chicken (Gallus Gallus), Mallard (Anas Platyrhynchos), American Kestrel (Falco Sparverius) And Black-Crowned Night-Heron (Nycticorax Nycticorax) Eggs, Moira A. Mckernan, Barnett A. Rattner, Jeff S. Hatfield, Robert C. Hale, Mary Ann Ottinger Jan 2010

Absorption And Biotransformation Of Polybrominated Diphenyl Ethers De-71 And De-79 In Chicken (Gallus Gallus), Mallard (Anas Platyrhynchos), American Kestrel (Falco Sparverius) And Black-Crowned Night-Heron (Nycticorax Nycticorax) Eggs, Moira A. Mckernan, Barnett A. Rattner, Jeff S. Hatfield, Robert C. Hale, Mary Ann Ottinger

United States Geological Survey: Staff Publications

We recently reported that air cell administration of penta-brominated diphenyl ether (penta-BDE; DE-71) evokes biochemical and immunologic effects in chicken (Gallus gallus) embryos at very low doses, and impairs pipping (i.e., stage immediately prior to hatching) and hatching success at 1.8 µg g-1 egg (actual dose absorbed) in American kestrels (Falco sparverius). In the present study, absorption of polybrominated diphenyl ether (PBDE) congeners was measured following air cell administration of a penta-BDE mixture (11.1 lg DE-71 g-1 egg) or an octa-brominated diphenyl ether mixture (octa BDE; DE-79; 15.4 lg DE-79 g- …


Paleogeographic, Paleoceanographic, And Tectonic Controls On Early Late Ordovician Graptolite Diversity Patterns, Daniel Goldman, Shuang-Ye Wu Jan 2010

Paleogeographic, Paleoceanographic, And Tectonic Controls On Early Late Ordovician Graptolite Diversity Patterns, Daniel Goldman, Shuang-Ye Wu

Department of Earth, Environment and Sustainability Faculty Publications

The Katian Age (early Late Ordovician) was a time of significant decline in marine biodiversity, but whether this decline was a real phenomenon or an artifact of the relatively few studies devoted to this interval requires further research. We examined the pattern of graptolite faunal changes across the boundary between the Climacograptus bicornis and Diplacanthograptus caudatus graptolite zones in North America and on several other continents.

A sharp decline in species diversity occurs in the Appalachian Basin. Scores for normalized diversity dropped from 20 in the C. bicornis Zone to 7 in the D. caudatus Zone. Only 11% of the …


Combined Effects Of Heat Waves And Droughts On Avian Communities Across The Conterminous United States, Thomas P. Albright, Anna M. Pidgeon, Chadwick D. Rittenhouse, Murray K. Clayton, Brian D. Wardlow, Curtis H. Flather, Patrick D. Culbert, Volker C. Radeloff Jan 2010

Combined Effects Of Heat Waves And Droughts On Avian Communities Across The Conterminous United States, Thomas P. Albright, Anna M. Pidgeon, Chadwick D. Rittenhouse, Murray K. Clayton, Brian D. Wardlow, Curtis H. Flather, Patrick D. Culbert, Volker C. Radeloff

National Drought Mitigation Center: Faculty Publications

Increasing surface temperatures and climatic variability associated with global climate change are expected to produce more frequent and intense heat waves and droughts in many parts of the world. Our goal was to elucidate the fundamental, but poorly understood, effects of these extreme weather events on avian communities across the conterminous United States. Specifically, we explored: (1) the effects of timing and duration of heat and drought events, (2) the effects of jointly occurring drought and heat waves relative to these events occurring in isolation, and (3) how effects vary among functional groups related to nest location and migratory habit, …


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 …


Evidence For Recent Population Bottlenecks In Northern Spotted Owls (Strix Occidentalis Caurina), W. Chris Funk, Eric D. Forsman, Matthew Johnson, Thomas D. Mullins, Susan M. Haig Jan 2010

Evidence For Recent Population Bottlenecks In Northern Spotted Owls (Strix Occidentalis Caurina), W. Chris Funk, Eric D. Forsman, Matthew Johnson, Thomas D. Mullins, Susan M. Haig

United States Geological Survey: Staff Publications

The northern spotted owl (Strix occidentalis caurina) is one of the most controversial threatened subspecies ever listed under the US Endangered Species Act. Despite protection of its remaining forest habitat, recent field studies show continued declines of northern spotted owls. One potential threat to northern spotted owls which has not yet been shown is loss of genetic variation from population bottlenecks. Bottlenecks can increase the probability of mating among related individuals, potentially causing inbreeding depression, and can decrease adaptive potential. Here we report evidence for recent bottlenecks in northern spotted owls using a large genetic dataset (352 individuals …


Subspecies Status And Population Genetic Structure In Piping Plover (Charadrius Melodus), Mark P. Miller, Susan M. Haig, Cheri L. Gratto-Trevor, Thomas D. Mullins Jan 2010

Subspecies Status And Population Genetic Structure In Piping Plover (Charadrius Melodus), Mark P. Miller, Susan M. Haig, Cheri L. Gratto-Trevor, Thomas D. Mullins

United States Geological Survey: Staff Publications

Piping Plover (Charadrius melodus) is a migratory shorebird that is listed as endangered in Canada and the U.S. Great Lakes and as threatened throughout the rest of its breeding and winter range. We undertook a comprehensive molecular-genetic investigation to (1) address subspecific taxonomy, (2) characterize population genetic structure, and (3) infer past bottlenecks and demographic processes in this species. Analyses included individuals from 23 U.S. states and Canadian provinces and were based on mitochondrial DNA sequences (580 base pairs, n = 245) and 8 nuclear microsatellite loci (n = 229). Our findings provide support for separate Atlantic and …


The Cleaning Of Burned And Contaminated Archaeological Maize Prior To 87sr/86sr Analysis, L.V. Benson, H. E. Taylor, T. I. Plowman, D. A. Roth, R. C. Antweiler Jan 2010

The Cleaning Of Burned And Contaminated Archaeological Maize Prior To 87sr/86sr Analysis, L.V. Benson, H. E. Taylor, T. I. Plowman, D. A. Roth, R. C. Antweiler

United States Geological Survey: Staff Publications

Accurate trace-metal and strontium-isotope analyses of archaeological corn cobs require that metal contaminants be removed prior to chemical analysis. Archaeological cobs are often coated with construction debris, dust, or soilwhich contains mineral particles. In addition, most archaeological cobs are partially or completely burned and the burned parts incorporate mineral debris in their hardened residual structures. Unburned cobs are weak ion exchangers and most metals within a cob are not firmly bound to cob organic matter; therefore, immersing cobs in acids and rinsing them in deionized water to remove mineral contaminants may result in the undesirable loss of metals, including strontium, …


Tree-Ring Dates And Demographic Change In The Southern Colorado Plateau And Rio Grande Regions, Michael S. Berry, Larry Benson Jan 2010

Tree-Ring Dates And Demographic Change In The Southern Colorado Plateau And Rio Grande Regions, Michael S. Berry, Larry Benson

United States Geological Survey: Staff Publications

In this chapter, tree-ring dates from the southern Colorado Plateau, Mogollon Highlands, and Rio Grande areas (fig. 3-1) (hereafter referred to as the study area) are used to estimate regional-scale timber-harvesting and construction activities between AD 600 and 1600 (the Basketmaker III through Pueblo IV periods). Within that time span, we focus our attention particularly on the AD 1045-1300 period, a time when anomalously wet periods alternated with megadroughts (fig. 3.2). Treering- date distributions (histograms) for eight archaeological subregions within the study area have been created using a database of more than twenty-four thousand tree-ring dates from archaeological sites. These …


Barcoding Bushmeat: Molecular Identification Of Central African And South American Harvested Vertebrates, Mitchell J. Eaton, Greta J. Meyers, Sergios-Orestis Kolokotronis, Matthew S. Leslie, Andrew P. Martin, George Amato Jan 2010

Barcoding Bushmeat: Molecular Identification Of Central African And South American Harvested Vertebrates, Mitchell J. Eaton, Greta J. Meyers, Sergios-Orestis Kolokotronis, Matthew S. Leslie, Andrew P. Martin, George Amato

United States Geological Survey: Staff Publications

The creation and use of a globally available database of DNA sequences from a standardized gene region has been proposed as a tool for species identification, assessing genetic diversity and monitoring the legal and illegal trade in wildlife species. Here, we contribute to the Barcode of Life Data System and test whether a short region of the mitochondrial cytochrome c oxidase subunit 1 (COX1) gene would reliably distinguish among a suite of commonly hunted African and South American mammal and reptile species. We used universal primers to generate reference barcode sequences of 645 bp for 23 species from five vertebrate …


Barcoding Bushmeat: Molecular Identification Of Central African And South American Harvested Vertebrates, Mitchell J. Eaton, Greta L. Meyers, Sergios-Orestis Kolokotronis, Matthew S. Leslie, Andrew P. Martin, George Amato Jan 2010

Barcoding Bushmeat: Molecular Identification Of Central African And South American Harvested Vertebrates, Mitchell J. Eaton, Greta L. Meyers, Sergios-Orestis Kolokotronis, Matthew S. Leslie, Andrew P. Martin, George Amato

United States Geological Survey: Staff Publications

The creation and use of a globally available database of DNA sequences from a standardized gene region has been proposed as a tool for species identification, assessing genetic diversity and monitoring the legal and illegal trade in wildlife species. Here, we contribute to the Barcode of Life Data System and test whether a short region of the mitochondrial cytochrome c oxidase subunit 1 (COX1) gene would reliably distinguish among a suite of commonly hunted African and South American mammal and reptile species. We used universal primers to generate reference barcode sequences of 645 bp for 23 species from five vertebrate …


The Role Of African Dust In The Formation Of Quaternary Soils On Mallorca, Spain And Implications For The Genesis Of Red Mediterranean Soils, Daniel R. Muhs, James Budahn, Anna Avila, Gary Skipp, Joshua Freeman, Deanna Patterson Jan 2010

The Role Of African Dust In The Formation Of Quaternary Soils On Mallorca, Spain And Implications For The Genesis Of Red Mediterranean Soils, Daniel R. Muhs, James Budahn, Anna Avila, Gary Skipp, Joshua Freeman, Deanna Patterson

United States Geological Survey: Staff Publications

African dust additions explain the origin of terra rossa soils that are common on the carbonate-platform island of Mallorca, Spain. Mineralogical and geochemical analyses indicate that Quaternary carbonate eolianites on Mallorca have a very high purity, usually composed of more than 90% carbonate minerals (calcite, dolomite, and aragonite). In contrast, terra rossa soils developed on these eolianites have lower carbonate contents and contain higher concentrations of quartz and other silicates. Analyses of immobile trace elements indicate that the non-carbonate fractions of the eolianites have distinctive Zr/Hf, La/Yb, Cr/Sc and Th/Ta values that differ from the superjacent terra rossa soils. These …


Assessing The Potential For Luminescence Dating Of Basalts, S. Tsukamoto, G. A.T. Duller, A. G. Wintle, Daniel R. Muhs Jan 2010

Assessing The Potential For Luminescence Dating Of Basalts, S. Tsukamoto, G. A.T. Duller, A. G. Wintle, Daniel R. Muhs

United States Geological Survey: Staff Publications

The possibility of dating basalt using luminescence was tested on four samples with independent age control from Cima volcanic !eld, California, with the ultimate aim of assessing whether the technique could be used to date sediments on the surface of Mars. Previous analysis of these samples had demonstrated that the infrared stimulated luminescence (IRSL) signal is most suitable for dating as it showed the lowest fading rate among various luminescence signals. In this study, changes in equivalent dose as a function of preheat are described. The ages for the two youngest Cima samples agree with the independent ages based on …


Citizen Professionals: The Effective Practices Of Experts Helping Community Organizations, Sarah Hippensteel Hall Jan 2010

Citizen Professionals: The Effective Practices Of Experts Helping Community Organizations, Sarah Hippensteel Hall

Antioch University Dissertations & Theses

Although numerous local, state, and federal laws and policies address water pollution, many problems remain. To address these problems thousands of groups of citizens, who are concerned with their water resources - rivers, streams, lakes, ponds, and groundwater - organized around the U.S. over the past several decades. To succeed, these community organizations need the resources and capacity to reach their goals. To gain capacity, some community organizations turn to people outside the organization for assistance. Citizen professionals are helpers who work jointly with an organization to help develop an organization's adaptive capacity to deal with challenges and achieve goals. …


Relating Fires’ Effect On Forest Succession And Forest's Effect On Fire Severity In One Burned And Unburned Environment, Tyler Jay Seiboldt Dec 2009

Relating Fires’ Effect On Forest Succession And Forest's Effect On Fire Severity In One Burned And Unburned Environment, Tyler Jay Seiboldt

Department of Environmental Studies: Undergraduate Student Theses

Wildfires are a natural part of many forest ecosystems and play a vital role in maintaining their health.  Wildfires can have a critical influence on a landscapes plant community through their relative frequency, seasonality, and severity.  One of the most heavily influenced regions by wildfire disturbance is the Klamath Mountain region of California.  I looked at the affect a wildfires severity had on the Whiskey creek valley within the Whiskeytown National Recreation Area.  8 tree species and 4 flower species were examined on both the burned and unburned regions within this valley nearly a year after the wildfire (May 17-23 …


Estimation Of Chlorophyll-A Concentration In Case Ii Waters Using Modis And Meris Data—Successes And Challenges, Wesley Moses, Anatoly Gitelson, Sergey Berdnikov, Vasiliy Povazhnyi Oct 2009

Estimation Of Chlorophyll-A Concentration In Case Ii Waters Using Modis And Meris Data—Successes And Challenges, Wesley Moses, Anatoly Gitelson, Sergey Berdnikov, Vasiliy Povazhnyi

School of Natural Resources: Faculty Publications

We present and discuss here the results of our work using MODIS (moderate resolution imaging spectroradiometer) and MERIS (medium resolution imaging spectrometer) satellite data to estimate the concentration of chlorophyll-a (chl-a) in reservoirs of the Dnieper River and the Sea of Azov, which are typical case II waters, i.e., turbid and productive. Our objective was to test the potential of satellite remote sensing as a tool for near-real-time monitoring of chl-a distribution in these water bodies. We tested the performance of a recently developed three-band model, and its special case, a two-band model, which use the reflectance at red and …


Geogram 2009, David J. Keeling Editor, Wku Department Of Geography And Geology Oct 2009

Geogram 2009, David J. Keeling Editor, Wku Department Of Geography And Geology

Earth, Environmental, and Atmospheric Sciences Publications

No abstract provided.


Droughtscape, Fall 2009, Kelly Smith Oct 2009

Droughtscape, Fall 2009, Kelly Smith

DroughtScape: Quarterly Newsletter of the National Drought Mitigation Center (2007–2023)

DroughtScape, Fall 2009


Heat And Smoke Effects On Red Brome Soil Seed Banks, Scott R. Abella, E. Cayenne Engel Oct 2009

Heat And Smoke Effects On Red Brome Soil Seed Banks, Scott R. Abella, E. Cayenne Engel

Public Policy and Leadership Faculty Research

Management of exotic plants that are annuals entails understanding and managing their soil seed banks. We completed a study of the influences of heat and liquid smoke on red brome (Bromus rubens) soil seed banks collected from Red Rock Canyon in southern Nevada as part of a collaborative fire effects monitoring effort with Bureau of Land Management - Las Vegas. We collected the samples from the 2005 Loop Fire, where we observed in a monitoring field study that exotic grasses such as red brome were relatively sparse in the first 2-3 years (which were during a dry period) following the …


Droughtscape, Summer 2009, Kelly Smith Jul 2009

Droughtscape, Summer 2009, Kelly Smith

DroughtScape: Quarterly Newsletter of the National Drought Mitigation Center (2007–2023)

U.S. Drought Monitor Forum, 2009

El Niño Could Bring Wet Winter After Hot Summer

Around the World

Agriculture Hit Hard in California, Texas

Predictable Patterns in Missouri River Basin?

Seeking Low-Flow Effects in Colorado, Southeast

VegDRI Began Coast-to-Coast Coverage in May


Land Rehabilitation Of Construction Damaged Parcel At Santa Fe Road And Hoover Avenue In San Luis Obispo, California, Patience J. West Jun 2009

Land Rehabilitation Of Construction Damaged Parcel At Santa Fe Road And Hoover Avenue In San Luis Obispo, California, Patience J. West

Earth and Soil Sciences

A plan for the rehabilitation of a construction damaged parcel of land with constructed swale running through it using native plants.


Droughtscape, Spring 2009, Kelly Smith Apr 2009

Droughtscape, Spring 2009, Kelly Smith

DroughtScape: Quarterly Newsletter of the National Drought Mitigation Center (2007–2023)

U.S. Drought Monitor Publishes Map 500!

Weakening La Niña May Mean Relief for Texas

Upcoming Workshops

Drought Impacts Worst in California, Texas

CoCoRaHS to Request Drought Impact Data, Too

NDMC Adds Researcher

K-12 Students Learn About Drought


Paleomagnetic Behavior Of Volcanic Rocks From Isla Socorro, Mexico, Elise Sbarbori, Lisa Tauxe, Avto Goguitchaichvili, Jaime Urrutia-Fucugauchi, Wendy A. Bohrson Jan 2009

Paleomagnetic Behavior Of Volcanic Rocks From Isla Socorro, Mexico, Elise Sbarbori, Lisa Tauxe, Avto Goguitchaichvili, Jaime Urrutia-Fucugauchi, Wendy A. Bohrson

All Faculty Scholarship for the College of the Sciences

The direction and magnitude of the geomagnetic field vary both spatially and temporally and undergo significant departures from that of a geocentric axial dipole. In order to properly characterize persistent behaviors, time-averaged field models must be based on the highest quality data. Here we present full-vector paleomagnetic data for volcanic units exposed in the southeast quadrant of the island of Socorro, Mexico. We carried out a joint expedition between the Scripps Institution of Oceanography and the Universidad Nacional Autónoma México to Isla Socorro in January of 2005 during which we collected oriented paleomagnetic samples from 21 sites, representing as many …


Structured Decision Making As A Conceptual Framework To Identify Thresholds For Conservation And Management, Julien Martin, Michael C. Runge, James D. Nichols, Bruce C. Lubow, William L. Kendall Jan 2009

Structured Decision Making As A Conceptual Framework To Identify Thresholds For Conservation And Management, Julien Martin, Michael C. Runge, James D. Nichols, Bruce C. Lubow, William L. Kendall

United States Geological Survey: Staff Publications

Thresholds and their relevance to conservation have become a major topic of discussion in the ecological literature. Unfortunately, in many cases the lack of a clear conceptual framework for thinking about thresholds may have led to confusion in attempts to apply the concept of thresholds to conservation decisions. Here, we advocate a framework for thinking about thresholds in terms of a structured decision making process. The purpose of this framework is to promote a logical and transparent process for making informed decisions for conservation.

Specification of such a framework leads naturally to consideration of definitions and roles of different kinds …