1,481 research outputs found

    Understanding the Biology of Clover Root Curculio and Improving Their Management Using Biofumigation in Alfalfa

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    Clover root curculio (CRC) is a pest of alfalfa where larvae feed belowground damaging alfalfa roots. Regional knowledge of CRC activity and biology is limited making the development of pest management strategies difficult. One potential management technique for soil-dwelling pests is the use of biofumigant containing cover crops. Biofumigation can affect the survival and behavior of pest insects. However, biofumigant crops have not been evaluated against CRC or as a rotational crop compatible with alfalfa. The goals of this research were to determine 1) phenology, population sizes, and root damage severity of CRC occurring in the Intermountain region and 2) the direct and indirect suppressive effects of biofumigant cover crop incorporations on CRC and its agronomic compatibility in rotation with alfalfa. First, I observed that larval activity occurred from mid-spring to mid-summer and local larval densities were generally lower than those reported in the eastern U.S. Adult CRC began emerging from the soil in mid-summer having two population peaks. After the second fall peak of adults was when most eggs were deposited which continued through early winter. CRC damage to taproots was cumulative, increasing as stands age, with most damage occurring in the first few years of stand life and mostly occurring in the top 20 cm of roots. While the incorporation of biofumigant crops appeared to be compatible with alfalfa and did not negatively affect yield, in field trials, biofumigation did not suppress CRC, disrupt egg laying, or decrease feeding damage. In one greenhouse trial, biofumigants significantly suppressed adult feeding rates more than non-biofumigant plants but the effect was not consistent. Biofumigant incorporation timing, for field trials in particular, may have contributed to the lack of CRC suppression. Overall, my research provides a better understanding of CRC phenology and activity in northern Utah and will assist in improving the timing of management approaches in alfalfa

    Extending the Latent Multinomial Model with Complex Error Processes and Dynamic Markov Bases

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    The latent multinomial model (LMM) model of Link et al. (2010) provided a general framework for modelling mark-recapture data with potential errors in identification. Key to this approach was a Markov chain Monte Carlo (MCMC) scheme for sampling possible configurations of the counts true capture histories that could have generated the observed data. This MCMC algorithm used vectors from a basis for the kernel of the linear map between the true and observed counts to move between the possible configurations of the true data. Schofield and Bonner (2015) showed that a strict basis was sufficient for some models of the errors, including the model presented by Link et al. (2010), but a larger set called a Markov basis may be required for more complex models. We address two further challenges with this approach: 1) that models with more complex error mechanisms do not fit easily within the LMM and 2) that the Markov basis can be difficult or impossible to compute for even moderate sized studies. We address these issues by extending the LMM to separately model the capture/demographic process and the error process and by developing a new MCMC sampling scheme using dynamic Markov bases. Our work is motivated by a study of Queen snakes (Regina septemvittata) in Kentucky, USA, and we use simulation to compare the use of PIT tags, with perfect identification, and brands, which are prone to error, when estimating survival rates

    Urbanization and Stream Salamanders: A Review, Conservation Options, and Research Needs

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    Urban areas are increasing in size and human population density. The implications of widespread urbanization are apparent for a wide variety of stream organisms, but the responses of stream-dwelling salamanders to urbanization have been understudied historically. Studies on this assemblage have increased sufficiently over the last decade to warrant a review and synthesis of current knowledge. Our survey of the literature indicates a research bias toward species within the Piedmont ecoregion of the USA and a strong emphasis on changes in species richness, relative abundance, and occupancy along an urbanization gradient. Very few investigators have examined vital rates for specific life stages, population dynamics over extended periods, or mechanistic explanations for the specific aspects of urbanization that drive species loss and decline. We reviewed a broad array of literature on stream salamanders to identify the key abiotic and biotic drivers that explain species responses in urban watersheds. Based on these findings and the applied ecological literature, we identified conservation options for urban areas where decision makers and stakeholders wish to preserve stream salamanders and their habitats. We have listed 7 future research priorities that will further efforts to conserve stream salamanders in rapidly urbanizing regions

    Tiling strategies for optical follow-up of gravitational wave triggers by wide field of view telescopes

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    Binary neutron stars are among the most promising candidates for joint gravitational-wave and electromagnetic astronomy. The goal of this work is to investigate the strategy of using gravitational wave sky-localizations for binary neutron star systems, to search for electromagnetic counterparts using wide field of view optical telescopes. We examine various strategies of scanning the gravitational wave sky-localizations on the mock 2015-16 gravitational-wave events. We propose an optimal tiling-strategy that would ensure the most economical coverage of the gravitational wave sky-localization, while keeping in mind the realistic constrains of transient optical astronomy. Our analysis reveals that the proposed tiling strategy improves the sky-localization coverage over naive contour-covering method. The improvement is more significant for observations conducted using larger field of view telescopes, or for observations conducted over smaller confidence interval of gravitational wave sky-localization probability distribution. Next, we investigate the performance of the tiling strategy for telescope arrays and compare their performance against monolithic giant field of view telescopes. We observed that distributing the field of view of the telescopes into arrays of multiple telescopes significantly improves the coverage efficiency by as much as 50% over a single large FOV telescope in 2016 localizations while scanning around 100 sq. degrees. Finally, we studied the ability of optical counterpart detection by various types of telescopes. In Our analysis for a range of wide field-of-view telescopes we found improvement in detection upon sacrificing coverage of localization in order to achieve greater observation depth for very large field-of-view - small aperture telescopes, especially if the intrinsic brightness of the optical counterparts are weak.Comment: Accepted for publication in A&A. 10 pages, 10 figure

    Southeast Utah Turfgrass Management Calendar

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    This is a calendar for turfgrass management for southeast Utah and includes guidelines for seeding, overseeding, sodding, fertilization, mowing, aeration, weed control, and irrigation

    St. George, Utah, Turfgrass Management Calendar

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    This is a calendar for turfgrass management for St. George, Utah, and includes guidelines for seeding, overseeding, sodding, fertilization, mowing, aeration, weed control, and irrigation

    Drag resistance of 2D electronic microemulsions

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    Motivated by recent experiments of Pillarisetty {\it et al}, \prl {\bf 90}, 226801 (2003), we present a theory of drag in electronic double layers at low electron concentration. We show that the drag effect in such systems is anomolously large, it has unusual temperature and magnetic field dependences accociated with the Pomeranchuk effect, and does not vanish at zero temperature

    The Diet of the Cumberland Plateau Salamander (Plethodon kentucki) in an old growth forest of southeastern Kentucky

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    Examining the diet of salamanders is important for understanding their effects on invertebrate communities and the interactions among sympatric salamander species. We examined the diet of the Cumberland Plateau Salamander, Plethodon kentucki (Mittleman), in an old growth forest in southeastern Kentucky. A total of 763 prey items were recovered from 73 salamanders with an average of 10.75 prey items per stomach. The four most important prey groups were Formicidae (ants), Araneae (spiders), Coleoptera (beetles), and Collembola (springtails). Overall, we found a total of 58 different prey types in the stomach contents from 20 invertebrate orders. This study represents one of the few successful uses of nonlethal gastric lavage methods on a large plethodontid salamander and the first description of P. kentucki diet identified to family and genus. Future work should examine diet throughout the year, compare prey species composition to sympatric salamander species, and look at local prey abundances and diversity to explore salamander foraging behavior

    The Diet of the Cumberland Plateau Salamander (Plethodon kentucki) in an old growth forest of southeastern Kentucky

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    Terrestrial lungless salamanders are known to reach very high densities in forested ecosystems of the United States. They can be important for the top down regulation of invertebrates Diets of 57% (31 of 54) Plethodonsalamanders are still poorly known The Cumberland Plateau Salamander (Plethodon kentucki) is a large plethodontid common in the Central Appalachians, however, its diet is only known from West Virginia DOI: 10.13140/RG.2.2.18118.4768
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