817 research outputs found

    N. E. Hansen\u27s Contributions to Alfalfa Breeding in North America

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    This bulletin provides biographical information about N.E. Hanson and his contributions to alfalfa breeding

    Alfalfa Varieties for South Dakota

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    Alfalfa varieties for South Dakota discusses varietal selection, persistence, winter hardiness, drought tolerance, disease and insect resistance, and use of alfalfa. Also included are definitions of terminology related to alfalfa crops

    Alfalfa Varieties for South Dakota

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    Alfalfa varieties for South Dakota discusses varietal selection, persistence, winter hardiness, drought tolerance, disease and insect resistance, and use of alfalfa. Also included are definitions of terminology related to alfalfa crops

    Alfalfa Varieties for South Dakota

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    Alfalfa varieties for South Dakota discusses varietal selection, persistence, winter hardiness, drought tolerance, disease and insect resistance, and use of alfalfa. Also included are definitions of terminology related to alfalfa crops

    Alfalfa Management

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    Guide to alfalfa management discusses alfalfa-grass mixtures, stand establishment, harvesting and grazing management, fertilization, insect, weed, and disease control, and using alfalfa as a soil-building crop

    The Violent Youth of Bright and Massive Cluster Galaxies and their Maturation over 7 Billion Years

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    In this study we investigate the formation and evolution mechanisms of the brightest cluster galaxies (BCGs) over cosmic time. At high redshift (z∼0.9z\sim0.9), we selected BCGs and most massive cluster galaxies (MMCGs) from the Cl1604 supercluster and compared them to low-redshift (z∼0.1z\sim0.1) counterparts drawn from the MCXC meta-catalog, supplemented by SDSS imaging and spectroscopy. We observed striking differences in the morphological, color, spectral, and stellar mass properties of the BCGs/MMCGs in the two samples. High-redshift BCGs/MMCGs were, in many cases, star-forming, late-type galaxies, with blue broadband colors, properties largely absent amongst the low-redshift BCGs/MMCGs. The stellar mass of BCGs was found to increase by an average factor of 2.51±0.712.51\pm0.71 from z∼0.9z\sim0.9 to z∼0.1z\sim0.1. Through this and other comparisons we conclude that a combination of major merging (mainly wet or mixed) and \emph{in situ} star formation are the main mechanisms which build stellar mass in BCGs/MMCGs. The stellar mass growth of the BCGs/MMCGs also appears to grow in lockstep with both the stellar baryonic and total mass of the cluster. Additionally, BCGs/MMCGs were found to grow in size, on average, a factor of ∼3\sim3, while their average S\'ersic index increased by ∼\sim0.45 from z∼0.9z\sim0.9 to z∼0.1z\sim0.1, also supporting a scenario involving major merging, though some adiabatic expansion is required. These observational results are compared to both models and simulations to further explore the implications on processes which shape and evolve BCGs/MMCGs over the past ∼\sim7 Gyr.Comment: Accepted for publication in MNRA

    Alfalfa Management on Dryland

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    Alfalfa management on dryland discusses alfalfa-grass mixtures, stand establishment, harvesting and grazing management, fertilization, insect, weed, and disease control, and using alfalfa as a soil-building crop

    Emotional engagements predict and enhance social cognition in young chimpanzees

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    Social cognition in infancy is evident in coordinated triadic engagements, that is, infants attending jointly with social partners and objects. Current evolutionary theories of primate social cognition tend to highlight species differences in cognition based on human-unique cooperative motives. We consider a developmental model in which engagement experiences produce differential outcomes. We conducted a 10-year-long study in which two groups of laboratory-raised chimpanzee infants were given quantifiably different engagement experiences. Joint attention, cooperativeness, affect, and different levels of cognition were measured in 5- to 12-month-old chimpanzees, and compared to outcomes derived from a normative human database. We found that joint attention skills significantly improved across development for all infants, but by 12 months, the humans significantly surpassed the chimpanzees. We found that cooperativeness was stable in the humans, but by 12 months, the chimpanzee group given enriched engagement experiences significantly surpassed the humans. Past engagement experiences and concurrent affect were significant unique predictors of both joint attention and cooperativeness in 5- to 12-month-old chimpanzees. When engagement experiences and concurrent affect were statistically controlled, joint attention and cooperation were not associated. We explain differential social cognition outcomes in terms of the significant influences of previous engagement experiences and affect, in addition to cognition. Our study highlights developmental processes that underpin the emergence of social cognition in support of evolutionary continuity

    Travois: An Alfalfa for Grazing

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    In 1948, M. W. Adams and G. Semeniuk recognized the economic potential of introducing alfalfa into ranges and pastures of the more arid parts of South Dakota. They initiated a breeding program directed toward developing very hardy, disease resistant alfalfas which would persist indefinitely when grazed by livestock. Travois is an outgrowth of that program and is believed to meet these requirements

    The Properties of Radio Galaxies and the Effect of Environment in Large Scale Structures at z∼1z\sim1

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    In this study we investigate 89 radio galaxies that are spectroscopically-confirmed to be members of five large scale structures in the redshift range of 0.65≤z≤0.960.65 \le z \le 0.96. Based on a two-stage classification scheme, the radio galaxies are classified into three sub-classes: active galactic nucleus (AGN), hybrid, and star-forming galaxy (SFG). We study the properties of the three radio sub-classes and their global and local environmental preferences. We find AGN hosts are the most massive population and exhibit quiescence in their star-formation activity. The SFG population has a comparable stellar mass to those hosting a radio AGN but are unequivocally powered by star formation. Hybrids, though selected as an intermediate population in our classification scheme, were found in almost all analyses to be a unique type of radio galaxies rather than a mixture of AGN and SFGs. They are dominated by a high-excitation radio galaxy (HERG) population. We discuss environmental effects and scenarios for each sub-class. AGN tend to be preferentially located in locally dense environments and in the cores of clusters/groups, with these preferences persisting when comparing to galaxies of similar colour and stellar mass, suggesting that their activity may be ignited in the cluster/group virialized core regions. Conversely, SFGs exhibit a strong preference for intermediate-density global environments, suggesting that dusty starbursting activity in LSSs is largely driven by galaxy-galaxy interactions and merging.Comment: 28 pages, 10 figures, accepted to MNRA
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