263 research outputs found
Creating New Opportunities for Ecosystem Restoration on Public Lands: An Analysis of the Potential for Bureau of Land Management Lands
THE INDUSTRY HAS CHANGED, HAVE YOU? THE AGCO STORY
AGCO Corporation is a success story in the agricultural machinery sector. Utilizing marketing strategies of out-sourcing, cross-over selling, and a full line of products, AGCO markets its own way. In 7 years, AGCO has 18 brands sold through 7,000 dealerships in 140 countries. Acquisition and consolidation powered the growth of AGCO using nontraditional buyout financing. Herein lies its real success.Agribusiness, Industrial Organization,
Identifying Target Markets for Landscape Plant Retail Outlets
Landscape plant retailers must identify target markets to maximize marketing effectiveness. A tobit process is used on a system of three equations with fourteen years of data identifies target markets for different retail outlets. Results, compared with a previous study, show effects of time on target markets.Crop Production/Industries,
Conserving Endangered Black-Footed Ferrets: Biological Threats, Political Challenges, and Lessons Learned
There may be few stories in the annals of wildlife management that are as dramatic as the near demise and comeback of the black-footed ferret (Mustela nigripes). Endemic only to North America, this charming little carnivore found only in the continent’s central grasslands was hardly known to science until the mid-20th century. By then, vast colonies of the prey it depended on for food and shelter, the prairie dog (Cynomys spp.), had been wiped out through disease (sylvatic plague) and an agricultural industry with little tolerance for burrowing and grazing rodents. At its low point, the species’ fate would come down to 18 remaining ferrets and a scientific gamble that humans could intervene to save a species on the very brink of extinction. With heroic efforts by federal, state, and private scientists, immediate extinction was forestalled, and a comeback effort mounted. Like so many endangered species stories, the ferret’s tale is a story of tragedy, luck, science, and the acts of people that will determine its ultimate fate. Understanding the challenges going forward for the ferret requires an understanding of the natural history and ecology of black-footed ferrets and prairie dogs, diseases and disease management, and the political landscape, which we present here. The future for black-footed ferrets remains unclear. Ultimately we will need to summon the efforts of conservation biologists, policy makers, and the agricultural industry to determine if ferrets will continue to exist as a valued and unique part of North America’s natural heritage
Modeling of Water Injection into a Vacuum
A loosely coupled two-phase vacuum water plume model has been developed. This model consists of a source flow model to describe the expansion of water vapor, and the Lagrangian equations of motion for particle trajectories. Gas/Particle interaction is modeled through the drag force induced by the relative velocities. Particles are assumed traveling along streamlines. The equations of motion are integrated to obtain particle velocity along the streamline. This model has been used to predict the mass flux in a 5 meter radius hemispherical domain resulting from the burst of a water jet of 1.5 mm in diameter, mass flow rate of 24.2 g/s, and stagnation pressure of 21.0 psia, which is the nominal Orbiter water dump condition. The result is compared with an empirical water plume model deduced from a video image of the STS-29 water dump. To further improve the model, work has begun to numerically simulate the bubble formation and bursting present in a liquid stream injected into a vacuum. The technique of smoothed particle hydrodynamics was used to formulate this simulation. A status and results of the on-going effort are presented and compared to results from the literature
Atmospheric carbon dioxide variability in the Community Earth System Model : evaluation and transient dynamics during the twentieth and twenty-first centuries
Author Posting. © American Meteorological Society, 2013. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Climate 26 (2013): 4447–4475, doi:10.1175/JCLI-D-12-00589.1.Changes in atmospheric CO2 variability during the twenty-first century may provide insight about ecosystem responses to climate change and have implications for the design of carbon monitoring programs. This paper describes changes in the three-dimensional structure of atmospheric CO2 for several representative concentration pathways (RCPs 4.5 and 8.5) using the Community Earth System Model–Biogeochemistry (CESM1-BGC). CO2 simulated for the historical period was first compared to surface, aircraft, and column observations. In a second step, the evolution of spatial and temporal gradients during the twenty-first century was examined. The mean annual cycle in atmospheric CO2 was underestimated for the historical period throughout the Northern Hemisphere, suggesting that the growing season net flux in the Community Land Model (the land component of CESM) was too weak. Consistent with weak summer drawdown in Northern Hemisphere high latitudes, simulated CO2 showed correspondingly weak north–south and vertical gradients during the summer. In the simulations of the twenty-first century, CESM predicted increases in the mean annual cycle of atmospheric CO2 and larger horizontal gradients. Not only did the mean north–south gradient increase due to fossil fuel emissions, but east–west contrasts in CO2 also strengthened because of changing patterns in fossil fuel emissions and terrestrial carbon exchange. In the RCP8.5 simulation, where CO2 increased to 1150 ppm by 2100, the CESM predicted increases in interannual variability in the Northern Hemisphere midlatitudes of up to 60% relative to present variability for time series filtered with a 2–10-yr bandpass. Such an increase in variability may impact detection of changing surface fluxes from atmospheric observations.The CESM project is supported
by the National Science Foundation and the Office of
Science (BER) of the U.S. Department of Energy.
Computing resources were provided by the Climate
Simulation Laboratory at NCAR’s Computational and
Information Systems Laboratory (CISL), sponsored by
the National Science Foundation and other agencies.
G.K.A. acknowledges support of a NOAA Climate and
Global Change postdoctoral fellowship. J.T.R., N.M.M.,
S.C.D., K.L., and J.K.M. acknowledge support of Collaborative
Research: Improved Regional and Decadal
Predictions of the Carbon Cycle (NSF AGS-1048827,
AGS-1021776,AGS-1048890). TheHIPPO Programwas
supported byNSF GrantsATM-0628575,ATM-0628519,
and ATM-0628388 to Harvard University, University of
California (San Diego), and by University Corporation
for Atmospheric Research, University of Colorado/
CIRES, by the NCAR and by the NOAAEarth System
Research Laboratory. Sunyoung Park, Greg Santoni,
Eric Kort, and Jasna Pittman collected data during
HIPPO. The ACME project was supported by the Office
of Biological and Environmental Research of the U.S.
Department of Energy under Contract DE-AC02-
05CH11231 as part of the Atmospheric Radiation Measurement
Program (ARM), the ARM Aerial Facility,
and the Terrestrial EcosystemScience Program. TCCON
measurements at Eureka were made by the Canadian
Network for Detection of Atmospheric Composition
Change (CANDAC) with additional support from the
Canadian Space Agency. The Lauder TCCON program
was funded by the New Zealand Foundation for Research
Science and Technology contracts CO1X0204,
CO1X0703, and CO1X0406. Measurements at Darwin
andWollongong were supported by Australian Research
Council Grants DP0879468 and DP110103118 and
were undertaken by David Griffith, Nicholas Deutscher,
and Ronald Macatangay. We thank Pauli Heikkinen,
Petteri Ahonen, and Esko Kyr€o of the Finnish Meteorological
Institute for contributing the Sodankyl€a
TCCON data. Measurements at Park Falls, Lamont, and
Pasadena were supported byNASAGrant NNX11AG01G
and the NASA Orbiting Carbon Observatory Program.
Data at these sites were obtained by Geoff Toon, Jean-
Francois Blavier, Coleen Roehl, and Debra Wunch.2014-01-0
Planetary Candidates Observed by Kepler V: Planet Sample from Q1-Q12 (36 Months)
The Kepler mission discovered 2842 exoplanet candidates with 2 years of data.
We provide updates to the Kepler planet candidate sample based upon 3 years
(Q1-Q12) of data. Through a series of tests to exclude false-positives,
primarily caused by eclipsing binary stars and instrumental systematics, 855
additional planetary candidates have been discovered, bringing the total number
known to 3697. We provide revised transit parameters and accompanying posterior
distributions based on a Markov Chain Monte Carlo algorithm for the cumulative
catalogue of Kepler Objects of Interest. There are now 130 candidates in the
cumulative catalogue that receive less than twice the flux the Earth receives
and more than 1100 have a radius less than 1.5 Rearth. There are now a dozen
candidates meeting both criteria, roughly doubling the number of candidate
Earth analogs. A majority of planetary candidates have a high probability of
being bonafide planets, however, there are populations of likely
false-positives. We discuss and suggest additional cuts that can be easily
applied to the catalogue to produce a set of planetary candidates with good
fidelity. The full catalogue is publicly available at the NASA Exoplanet
Archive.Comment: Accepted for publication, ApJ
Development of a Benchmark Eddy Flux Evapotranspiration Dataset for Evaluation of Satellite-Driven Evapotranspiration Models Over the CONUS
A large sample of ground-based evapotranspiration (ET) measurements made in the United States, primarily from eddy covariance systems, were post-processed to produce a benchmark ET dataset. The dataset was produced primarily to support the intercomparison and evaluation of the OpenET satellite-based remote sensing ET (RSET) models and could also be used to evaluate ET data from other models and approaches. OpenET is a web-based service that makes field-delineated and pixel-level ET estimates from well-established RSET models readily available to water managers, agricultural producers, and the public. The benchmark dataset is composed of flux and meteorological data from a variety of providers covering native vegetation and agricultural settings. Flux footprint predictions were developed for each station and included static flux footprints developed based on average wind direction and speed, as well as dynamic hourly footprints that were generated with a physically based model of upwind source area. The two footprint prediction methods were rigorously compared to evaluate their relative spatial coverage. Data from all sources were post-processed in a consistent and reproducible manner including data handling, gap-filling, temporal aggregation, and energy balance closure correction. The resulting dataset included 243,048 daily and 5,284 monthly ET values from 194 stations, with all data falling between 1995 and 2021. We assessed average daily energy imbalance using 172 flux sites with a total of 193,021 days of data, finding that overall turbulent fluxes were understated by about 12% on average relative to available energy. Multiple linear regression analyses indicated that daily average latent energy flux may be typically understated slightly more than sensible heat flux. This dataset was developed to provide a consistent reference to support evaluation of RSET data being developed for a wide range of applications related to water accounting and water resources management at field to watershed scales
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