460 research outputs found

    Validation of Factors Influencing Successful Small Scale Farming in North Carolina

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    This phase of the research project involves developing a survey instrument to test the validity and predictive value of the variables identified in previous case studies. Given the importance of small farm viability, this research project focuses on identifying ways to further enhance successful small farming in North Carolina. The survey instrument was designed to solicit production and financial data, attitudes and beliefs about farming, as well as demographic questions. The results demonstrated that successful farmers indicators were the “love of farming” and “manageable debt”. Other strong indicators of successful farmers included a combination of marketing strategies that utilize technology such as websites as well as local farmers markets and educational level. Knowledge about the successful small farm is likely to provide valuable information about how to evaluate the “successfulness” of small farm operations and produce best practices models for small scale farm operations.Small Farmers, Agribusiness, Agribusiness, Farm Management,

    Case Studies of Successful Small Scale Farming in North Carolina

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    The goal of this study focuses on determining factors that contribute to a successful small farm in North Carolina and on identifying ways to further enhance successful small farming. North Carolina farms vary extensively in size and other characteristics, ranging from very small retirement and residential farms to establishments with millions of dollars in sales. Farming continues to be a distinctive industry in part because most production, even among very large farms, is carried out on family-operated farms whose operators often balance farm and off-farm employment and investment decisions. The case studies of successful small farmers conducted in November 2007 were the primary sources of data. The North Carolina Cooperative Extension Program identified three “successful” farmers from its sampling frame to participate in the case studies. Researchers identified sets of variables associated with small farm success through various literature, published and unpublished reports and recommendations from experts in the field. After the variables were operationalized, a questionnaire was developed as a guide for conducting the case studies interview protocols. Each case study consisted of a one-visit protocol with electronic follow-up. Researchers conducted on-site interviews, and then toured the individual farms. The case study farmers used a diverse mix of enterprises including specialty crops and a combination of marketing strategies. The educational level ranged from post high school to Ph.D. although all farmers attended several workshops. All farmers minimized risk through diversity, contractual sales and insurance. Only one farmer used computers for record keeping and finance. The overall “love of farming” seemed to be the biggest driving force behind the farmer’s view of success.Small Farmer, Agribusiness, Agricultural Finance, Teaching/Communication/Extension/Profession,

    Spacelab system analysis: A study of the Marshall Avionics System Testbed (MAST)

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    An analysis of the Marshall Avionics Systems Testbed (MAST) communications requirements is presented. The average offered load for typical nodes is estimated. Suitable local area networks are determined

    Spacelab system analysis: A study of communications systems for advanced launch systems

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    An analysis of the required performance of internal avionics data bases for future launch vehicles is presented. Suitable local area networks that can service these requirements are determined

    Bifurcation and upwelling of the equatorial undercurrent west of the Galapagos Archipelago

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    Author Posting. © American Meteorological Society, 2020. 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 Physical Oceanography 50(4), (2020): 887-905, doi:10.1175/JPO-D-19-0110.1.The Equatorial Undercurrent (EUC) encounters the GalĂĄpagos Archipelago on the equator as it flows eastward across the Pacific. The impact of the GalĂĄpagos Archipelago on the EUC in the eastern equatorial Pacific remains largely unknown. In this study, the path of the EUC as it reaches the GalĂĄpagos Archipelago is measured directly using high-resolution observations obtained by autonomous underwater gliders. Gliders were deployed along three lines that define a closed region with the GalĂĄpagos Archipelago as the eastern boundary and 93°W from 2°S to 2°N as the western boundary. Twelve transects were simultaneously occupied along the three lines during 52 days in April–May 2016. Analysis of individual glider transects and average sections along each line show that the EUC splits around the GalĂĄpagos Archipelago. Velocity normal to the transects is used to estimate net horizontal volume transport into the volume. Downward integration of the net horizontal transport profile provides an estimate of the time- and areal-averaged vertical velocity profile over the 52-day time period. Local maxima in vertical velocity occur at depths of 25 and 280 m with magnitudes of (1.7 ± 0.6) × 10−5 m s−1 and (8.0 ± 1.6) × 10−5 m s−1, respectively. Volume transport as a function of salinity indicates that water crossing 93°W south (north) of 0.4°S tends to flow around the south (north) side of the GalĂĄpagos Archipelago. Comparisons are made between previous observational and modeling studies with differences attributed to effects of the strong 2015/16 El Niño event, the annual cycle of local winds, and varying longitudes between studies of the equatorial Pacific.This work was supported by National Science Foundation (Grants OCE-1232971 and OCE-1233282) and the NASA Earth and Space Science Fellowship Program (Grant 80NSSC17K0443)

    Sarmentine, a natural herbicide from Piper species with multiple herbicide mechanisms of action

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    Sarmentine, 1-(1-pyrrolidinyl)-(2E,4E)-2,4-decadien-1-one, is a natural amide isolated from the fruits of Piper species. The compound has a number of interesting biological properties, including its broad-spectrum activity on weeds as a contact herbicide. Initial studies highlighted a similarity in response between plants treated with sarmentine and herbicidal soaps such as pelargonic acid (nonanoic acid). However, little was known about the mechanism of action leading to the rapid desiccation of foliage treated by sarmentine. In cucumber cotyledon disc-assays, sarmentine induced rapid light-independent loss of membrane integrity at 100 ”M or higher concentration, whereas 3 mM pelargonic acid was required for a similar effect. Sarmentine was between 10 and 30 times more active than pelargonic acid on wild mustard, velvetleaf, redroot pigweed and crabgrass. Additionally, the potency of 30 ”M sarmentine was greatly stimulated by light, suggesting that this natural product may also interfere with photosynthetic processes. This was confirmed by observing a complete inhibition of photosynthetic electron transport at that concentration. Sarmentine also acted as an inhibitor of photosystem II on isolated thylakoid membranes by competing for the binding site of plastoquinone. This can be attributed in part to structural similarities between herbicides like sarmentine and diuron. While this mechanism of action accounts for the light stimulation of the activity of sarmentine, it does not account for its ability to destabilize membranes in darkness. In this respect, sarmentine has some structural similarity to crotonoyl-CoA, the substrate of enoyl-ACP reductase, a key enzyme in the early steps of fatty acid synthesis. Inhibitors of this enzyme, such as triclosan, cause rapid loss of membrane integrity in the dark. Sarmentine inhibited the activity of enoyl-ACP reductase, with an I50app of 18.3 ”M. Therefore, the herbicidal activity of sarmentine appears to be a complex proces

    The equatorial current system west of the Galapagos Islands during the 2014-16 El Niño as observed by underwater gliders

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    Author Posting. © American Meteorological Society, 2021. 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 Physical Oceanography 51(1),(2021): 3-17, https://doi.org/10.1175/JPO-D-20-0064.1.The strong El Niño of 2014–16 was observed west of the GalĂĄpagos Islands through sustained deployment of underwater gliders. Three years of observations began in October 2013 and ended in October 2016, with observations at longitudes 93° and 95°W between latitudes 2°N and 2°S. In total, there were over 3000 glider-days of data, covering over 50 000 km with over 12 000 profiles. Coverage was superior closer to the GalĂĄpagos on 93°W, where gliders were equipped with sensors to measure velocity as well as temperature, salinity, and pressure. The repeated glider transects are analyzed to produce highly resolved mean sections and maps of observed variables as functions of time, latitude, and depth. The mean sections reveal the structure of the Equatorial Undercurrent (EUC), the South Equatorial Current, and the equatorial front. The mean fields are used to calculate potential vorticity Q and Richardson number Ri. Gradients in the mean are strong enough to make the sign of Q opposite to that of planetary vorticity and to have Ri near unity, suggestive of mixing. Temporal variability is dominated by the 2014–16 El Niño, with the arrival of depressed isopycnals documented in 2014 and 2015. Increases in eastward velocity advect anomalously salty water and are uncorrelated with warm temperatures and deep isopycnals. Thus, vertical advection is important to changes in heat, and horizontal advection is relevant to changes in salt. Implications of this work include possibilities for future research, model assessment and improvement, and sustained observations across the equatorial Pacific.We gratefully acknowledge the support of the National Science Foundation (OCE-1232971, OCE-1233282) and the Ocean Observing and Monitoring Division of the National Oceanographic and Atmospheric Administration (NA13OAR4830216)

    The Pacific Equatorial Undercurrent in three generations of global climate models and glider observations

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    Author Posting. © American Geophysical Union, 2020. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 125, (2020): e2020JC016609, doi:10.1029/2020JC016609.The Equatorial Undercurrent (EUC) is a vital component of the coupled ocean‐atmosphere system in the tropical Pacific. The details of its termination near the GalĂĄpagos Islands in the eastern Pacific have an outsized importance to regional circulation and ecosystems. Subject to diverse physical processes, the EUC is also a rigorous benchmark for global climate models (GCMs). Simulations of the EUC in three generations of GCMs are evaluated relative to recent underwater glider observations along 93°W. Simulations of the EUC have improved, but a slow bias of ~36% remains in the eastern Pacific, along with a dependence on resolution. Additionally, the westward surface current is too slow, and stratification is too strong (weak) by ~50% above (within) the EUC. These biases have implications for mixing in the equatorial cold tongue. Downstream lies the GalĂĄpagos, now resolved to varying degrees by GCMs. Properly representing the GalĂĄpagos is necessary to avoid new biases as the EUC improves.We gratefully acknowledge support from the National Science Foundation (OCE‐1232971 and OCE‐1233282) and the Global Ocean Monitoring and Observing program (formerly the Ocean Observing and Monitoring Division) of the National Oceanographic and Atmospheric Administration (NA13OAR4830216).2021-04-2
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