419 research outputs found

    Sustainable Grassland Management: An Exploratory Study of Progressive Ranchers in Nebraska

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    Well-managed grasslands provide numerous ecosystem services. Ranchers who employ sustainable grazing practices limit grassland conversion and conserve critical habitats. This phenomenological study explored the grassland management decisions of progressive ranchers in Nebraska. Each individual interviewed for this study is proactive about the state of their grasslands, whether they are motivated by financial or conservation factors. Throughout the evolution of their businesses, these ranchers have taken steps to improve their management techniques and continue to employ new strategies while planning for the long-term productivity of their grasslands. For policy makers and educators seeking to improve grassland management decisions, demonstrating new methods to be economical, promoting stewardship, and allowing for flexible implementation may increase acceptance of recommendations. Because progressive ranchers’ livelihoods are connected to the land, and they are long-term goal oriented, they closely scrutinize, yet are open to advancing grassland management practices that benefit their cash flow, their pastures, their animals, and their families

    Sustainable Grassland Management: An Exploratory Study of Progressive Ranchers in Nebraska

    Get PDF
    Well-managed grasslands provide numerous ecosystem services. Ranchers who employ sustainable grazing practices limit grassland conversion and conserve critical habitats. This phenomenological study explored the grassland management decisions of progressive ranchers in Nebraska. Each individual interviewed for this study is proactive about the state of their grasslands, whether they are motivated by financial or conservation factors. Throughout the evolution of their businesses, these ranchers have taken steps to improve their management techniques and continue to employ new strategies while planning for the long-term productivity of their grasslands. For policy makers and educators seeking to improve grassland management decisions, demonstrating new methods to be economical, promoting stewardship, and allowing for flexible implementation may increase acceptance of recommendations. Because progressive ranchers’ livelihoods are connected to the land, and they are long-term goal oriented, they closely scrutinize, yet are open to advancing grassland management practices that benefit their cash flow, their pastures, their animals, and their families

    Factors influencing ranchers’ intentions to manage for vegetation heterogeneity and promote cross-boundary management in the northern Great Plains

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    Most private grasslands in the Great Plains are managed with the goal to optimize beef production, which tends to homogenize rangeland habitats. The subsequent loss of vegetation heterogeneity on private lands is detrimental to ecosystem function. However, conservation planners should understand the factors that lead to variation in management of rangelands. We used a mail survey targeted to ranchers in counties with intact rangeland in North Dakota, South Dakota, and Nebraska in 2016 to examine factors predicted to be related to attitudes about strategies leading to heterogeneity such as innovativeness and low risk aversion, and intended behaviors associated with creation of heterogeneity. We used survey questions and a set of relevant scales to examine predictors of behavioral intentions for rangeland management and conservation. Attitudes about fire and prairie dogs, two strategies that create heterogeneity, were largely negative, and ranchers with positive attitudes about fire and prairie dogs and higher perceived behavioral control of their ranch and surrounding landscapes had greater intention to engage in heterogeneity-promoting behaviors. Social norms were also important in predicting intended behaviors and attitudes. Our research suggests that heterogeneity of grasslands may remain low unless land managers understand the importance of spatial and temporal heterogeneity and recognize prescribed fire and prairie dogs, and other burrowing colonial mammals, as principal drivers of ecological processes on rangelands. Conservation organizations may find success by modeling management tools, reducing the perceived effort producers must make to adopt behaviors that support heterogeneity, and by developing programs that work to change social norms around fire and prairie dogs

    Grassland Bird Responses to Three Edge Types in a Fragmented Mixed- Grass Prairie Réactions des oiseaux de prairie à trois types de bordures dans une prairie mixte fragmentée

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    ABSTRACT. One possible factor that may have contributed to the decline of grassland bird populations is edge avoidance. In the mixed-grass prairie, habitat fragmentation is often caused by juxtaposition of habitats with vegetation that is structurally similar to prairie, making it difficult to understand why birds avoid habitat edges. We hypothesized that display height or resource-use strategy, i.e., the degree to which a species depends on grassland habitat, might explain variation in sensitivity to habitat edges among different species of grassland birds. To test our hypotheses, we used data on the abundance of grassland birds in native mixed-grass prairie fields in southern Alberta, Canada, from 2000 to 2002. Point counts were conducted up to 4.1 km from croplands, 2.2 km from roads, and 1.8 km from wetlands. We used nonlinear regression models to determine the distance at which relative abundance of 12 bird species changed in response to edge, and linear regression to determine if display height or resource-use strategy explained variation in response to different types of edges. Variation in response to edge was not explained by display height or resource-use strategy. However, six species avoided wetland edges, two avoided roads, and four avoided cropland. Two species of conservation concern, Chestnut-collared Longspurs (Calcarius ornatus) and Sprague's Pipits (Anthus spragueii), declined in abundance by 25% or more within 1.95 km and 0.91 km, respectively, of cropland edges. Because Chestnut-collared Longspurs avoided croplands to at least 1.95 km, it will be important to prevent further fragmentation of mixed-grass prairies by agriculture. RÉSUMÉ. L'Ă©vitement des bordures est un des facteurs avancĂ©s dans le dĂ©clin des populations d'oiseaux de prairie. Dans la prairie mixte, la fragmentation d'habitat se prĂ©sente souvent sous la forme d'une juxtaposition de milieux dont la vĂ©gĂ©tation est structurellement similaire Ă  la prairie, ce qui rend difficile de comprendre pourquoi les oiseaux Ă©vitent les bordures d'habitat. Nous avons Ă©mis l'hypothĂšse voulant que la hauteur de parade ou la stratĂ©gie d'utilisation des ressources, c'est-Ă -dire Ă  quel degrĂ© une espĂšce dĂ©pend de l'habitat de prairie, expliquerait peut-ĂȘtre la variation de sensibilitĂ© aux bordures chez diffĂ©rentes espĂšces d'oiseaux de prairie. Afin de tester notre hypothĂšse, nous avons utilisĂ© des donnĂ©es d'abondance des oiseaux de prairie dans des champs de prairie mixte naturelle du sud de l'Alberta, au Canada, de 2000 Ă  2002. Des dĂ©nombrements par points d'Ă©coute ont Ă©tĂ© effectuĂ©s jusqu'Ă  4,1 km de terres cultivĂ©es, jusqu'Ă  2,2 km de routes et jusqu'Ă  1,8 km de milieux humides. Nous avons utilisĂ© la rĂ©gression non linĂ©aire dans le but de dĂ©terminer la distance Ă  laquelle l'abondance relative de 12 espĂšces d'oiseaux changeait en rĂ©action aux bordures, et la rĂ©gression linĂ©aire pour Ă©tablir si la hauteur de parade ou la stratĂ©gie d'utilisation des ressources expliquait la variation de rĂ©action selon les diffĂ©rents types de bordure. La variation dans la rĂ©action aux bordures n'a pas Ă©tĂ© expliquĂ©e par la hauteur de parade ni par la stratĂ©gie d'utilisation des ressources. Toutefois, six espĂšces ont Ă©vitĂ© les bordures avec les milieux humides, deux ont Ă©vitĂ© celles avec les routes et quatre, celles avec les terres cultivĂ©es. L'abondance de deux espĂšces dont la conservation est prĂ©occupante, le Plectrophane Ă  ventre noir (Calcarius ornatus) et le Pipit de Sprague (Anthus spragueii), a dĂ©clinĂ© d'au moins 25 % en deçà de 1,95 km et de 0,91 km d'une bordure de terre cultivĂ©e, respectivement. Étant donnĂ© que le plectrophane a Ă©vitĂ© les terres cultivĂ©es par 1,95 km au minimum, il sera important d'empĂȘcher davantage la fragmentation des prairies mixtes par l'agriculture

    An Integration Testing Facility for the CERN Accelerator Controls System

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    A major effort has been invested in the design, development, and deployment of the LHC Control System. This large control system is made up of a set of core components and dependencies, which although tested individually, are often not able to be tested together on a system capable of representing the complete control system environment, including hardware. Furthermore this control system is being adapted and applied to CERN's whole accelerator complex, and in particular for the forthcoming renovation of the PS accelerators. To ensure quality is maintained as the system evolves, and toimprove defect prevention, the Controls Group launched a project to provide a dedicated facility for continuous, automated, integration testing of its core components to incorporate into its production process. We describe the project, initial lessons from its application, status, and future directions

    Eruption of Shallow Crystal Cumulates during Explosive Phonolitic Eruptions on Tenerife, Canary Islands

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    The recent eruptive history on the island of Tenerife is characterized in part by the presence of zoned phonolitic ignimbrites, some of which prominently display two types of juvenile clasts (i.e. light-colored, aphyric pumices alongside darker, more crystal-rich pumices, here dubbed ‘crystal-poor' and ‘crystal-rich', respectively). Petrographic observation of the crystal-rich pumices reveals intensely resorbed and intergrown mineral textures, consistent with the system reaching a high crystallinity, followed by perturbation and remobilization prior to eruption. Some trace elements show anomalous concentrations in such crystal-rich pumices (e.g. bulk Ba > 2000 ppm alongside low Zr and a positive Eu anomaly) indicative of crystal accumulation (of feldspar ± biotite). Many biotite and feldspar crystals are reversely zoned, with rim concentrations that are high in Ba but low in Sr, implying crystallization from an ‘enriched' melt, potentially derived from remobilization by partial melting of the aforementioned cumulate zones. Given (1) the presence of cumulates in the eruptive record on Tenerife and a bimodality of pumice textures, (2) the presence of three dominant compositions (basanite, phonotephrite, phonolite, separated by compositional gaps) in the volcanic record, and (3) abundant support for crystal fractionation as the dominant drive for magmatic evolution in Tenerife, it is hypothesized that crystal-poor magmas are extracted from mushy reservoirs in both the lower and upper crust. The thermodynamic software MELTS is used to test a polybaric differentiation model whereby phonolites (sensu lato) are generated by extraction of residual liquids from an intermediate-crystallinity phonotephritic mush in the upper crust, which is in turn generated from the residual liquids of an intermediate-crystallinity basanitic mush at deeper levels. Latent heat spikes following crystallization of successive phases in the upper crustal reservoir provide a thermal buffering mechanism to slow down cooling and crystallization, permitting enhanced melt extraction at a particular crystallinity interval (mostly ∌40-60 vol. % crystals). MELTS modeling typically fits the observed chemical data adequately, although some major elements (mostly Al2O3) also indicate partial ‘cannibalization' of feldspar along with some magma mixing (and potentially minor crustal contamination

    Emerging market financial services development: the case of leasing in Poland and China

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    The aim of this paper is to present Polish and Chinese developments in this area in the period of 1999–2009 for the former and 2005–2008 the latter and then to compare both markets for 2007 and 2008 using different metrics. The time horizon is limited due to the lack of Chinese data. The results show that both economies used leasing to finance ongoing business and both markets have many common features. The results show also that although the Chinese leasing market is less developed, it catches up with the more developed Polish counterpart

    The Arabidopsis AAA ATPase SKD1 is involved in multivesicular endosome function and interacts with its positive regulator LYST-INTERACTING PROTEIN5

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    In yeast and mammals, the AAA ATPase Vps4p/SKD1 (for Vacuolar protein sorting 4/SUPPRESSOR OF K+ TRANSPORT GROWTH DEFECT1) is required for the endosomal sorting of secretory and endocytic cargo. We identified a VPS4/SKD1 homolog in Arabidopsis thaliana, which localizes to the cytoplasm and to multivesicular endosomes. In addition, green fluorescent protein-SKD1 colocalizes on multivesicular bodies with fluorescent fusion protein endosomal Rab GTPases, such as ARA6/RabF1, RHA1/RabF2a, and ARA7/RabF2b, and with the endocytic marker FM4-64. The expression of SKD1E232Q, an ATPase-deficient version of SKD1, induces alterations in the endosomal system of tobacco (Nicotiana tabacum) Bright Yellow 2 cells and ultimately leads to cell death. The inducible expression ofSKD1E232Q in Arabidopsis resulted in enlarged endosomes with a reduced number of internal vesicles. In a yeast two-hybrid screen using Arabidopsis SKD1 as bait, we isolated a putative homolog of mammalian LYST-INTERACTING PROTEIN5 (LIP5)/SKD1 BINDING PROTEIN1 and yeast Vta1p (for Vps twenty associated 1 protein). Arabidopsis LIP5 acts as a positive regulator of SKD1 by increasing fourfold to fivefold its in vitro ATPase activity. We isolated a knockout homozygous Arabidopsis mutant line with a T-DNA insertion in LIP5. lip5 plants are viable and show no phenotypic alterations under normal growth conditions, suggesting that basal SKD1 ATPase activity is sufficient for plant development and growth.Facultad de Ciencias Agrarias y Forestale

    Third International Conference on Applications of Optics and Photonics

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    Organic semiconductor rubrene (C42H28) belongs to most preferred spintronic materials because of the high charge carrier mobility up to 40 cm(2)(V.s)(-1). However, the fabrication of a defect-free, polycrystalline rubrene for spintronic applications represents a difficult task. We report preparation and properties of rubrene thin films deposited by pulsed laser evaporation of solidified solutions. Samples of rubrene dissolved in aromatic solvents toluene, xylene, dichloromethane and 1,1-dichloroethane (0.23-1% wt) were cooled to temperatures in the range of 16.5-163 K and served as targets. The target ablation was provided by a pulsed 1064 nm or 266 nm laser. For films of thickness up to 100 nm deposited on Si, glass and ITO glass substrates, the Raman and AFM data show presence of the mixed crystalline and amorphous rubrene phases. Agglomerates of rubrene crystals are revealed by SEM observation too, and presence of oxide/peroxide (C42H28O2) in the films is concluded from matrix-assisted laser desorption/ionization time-offlight spectroscopic analysis

    The secret life of wild animals revealed by accelerometer data: how landscape diversity and seasonality influence the behavioural types of European hares

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    Context Landscape composition and configuration, as well as seasonal landscape dynamics shape the behaviour, movement and energy expenditure of animals, i.e. foraging, hiding or fleeing, and ultimately survival. Especially in highly modified agricultural systems, it is crucial to understand how animal behaviour is influenced by landscape context to develop sustainable land management concepts. Objectives We show how landscape composition and configuration, together with seasonal dynamics affect animal behavioural types, accounting for the different life-history events in both sexes. Methods We investigated 34 European hares in two contrasting agricultural landscapes (a simple and a complex landscape) by using tri-axial accelerometer data to classify the animals’ behaviour into five categories: resting, foraging, moving, grooming and standing upright (i.e. vigilance behaviour). We tested whether the amount of behaviours per category changed with landscape composition and configuration, season and sex. Results During peak breeding, hares in areas of high habitat diversity rested more, moved less and spent less time searching for resources. During winter, hares moved more and rested less. Females rested less and foraged more in areas with large agricultural fields. Conclusions A complex landscape is particularly important during the breeding season, allowing animals to allocate enough energy into reproduction. In winter, hares in areas of low habitat diversity may not find enough thermal and anti-predator shelter to move as much as they would need to meet their requirements. Hence, high habitat diversity and small field sizes guarantee species persistence in human-altered agricultural areas throughout the year
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