140,980 research outputs found

    Optimal Grazing Termination Date for Dual-Purpose Winter Wheat Production

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    Dual-purpose winter wheat (fall-winter forage plus grain) production is an important economic enterprise in the southern Great Plains. Grazing termination to enable grain production is a critical decision. The objective is to determine the optimal grazing termination date for dual-purpose wheat. The value of knowing the occurrence of first hollow stem (FHS), a wheat growth threshold for grazing termination, is also determined. Results indicate that for most price situations grazing should be terminated at or before FHS. Marginal wheat returns from extended grazing were negative and the value of FHS information ranges from 1.50to1.50 to 10 per acre.dual-purpose, first hollow stem, plateau function, stocker cattle, value of information, wheat, Agribusiness, Agricultural Finance, Crop Production/Industries, Farm Management, Land Economics/Use, Livestock Production/Industries, Production Economics, Q12, Q16,

    Nexos iconográficos entre las columnas de Tula y los discos de oro de Chichén Itzá. 26. Arqueología

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"Semiotic analysis of Prehis­toric texts, en Semiotics, J.Deely (ed.), N.Y., Un iversity Press of Amer ica, 1987, pp. 183-192. •Slocker, T. y E.Kylar 1984. "Aztec warfare. Sacrifice and cannibalism", en The Explorers Journal, mím 62, pp. 126-133.•Stocker, T., S. Meltzoff y S.Armsev 1979. "Further incerpretations in Formative period iconography", en American antiquity , núm. 45, pp. 740-58.•Stocker T.y M.Spence 1974. "Obsidian eccencrics from Central Mexico'', en Studies in ancient Tollan, R. Diehl (ed.), University of Missouri Monographs in Anthropology, núm. l, pp. 88-94.•Tezozomoc , Hernando Alvarado 1975. Crónica mexicayotl , México, UNAM.•Tozzer ,A. 1957. "Chichén Itzá and its Cenote of Sacrifice: A comparative scudy of contemporaneous Maya and Toltec", en Memoirs of the Peobody Museum of Archaeologyond Ethnology, vols. 11-12.•Umberger, E. 1987. Antiques, revivals, and references to the pase in the Aztec are, en Res, núm. 13, pp. 61-105.•Van de Guchte, M. 1999. "The Inca cognition of landscape", en Archaeologies of landscape: Contemporary perspectives, T. Ashmore y B. Knapp (eds.), Oxford, Blackwell

    Reconsideración del elemento trilobulado en Mesoamérica: examen de los datos, interpretaciones sobre su continuidad y sugerencias para investigaciones futuras. 30. Arqueología

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Aztec Warfare, Norman, University of Oklahoma Press.Healan, D. 1986. “Technological and Nontechnological Aspects of an Obsidian Workshop Excavated at Tula, Hidalgo”, en Barry Isaacs (ed.), Economic Aspects of Prehispanic Highland Mexico, Greenwich, Conn, JAI Press, pp. 133-152.Heyden, D. 1986. “Metaphors, Nahualtocaitl, and Other ‘Disguised’ Terms Among the Aztecs”, en G. Gossen (ed.), Symbol and Meaning Beyond the Closed Community: Essays in Mesoamerican Ideas, Studies in Culture and Society, vol. 1, Albany, Institute for Mesoamerican Studies, University of Albany Press, State University of New York, pp. 35-43.Horcasitas, F., y D. Heyden (trad.) 1971. Book of the Gods and Rites and the Ancient Calendar (by) Fray Diego Duran, Norman, University of Oklahoma Press.Joralemon, P. 1976. “The Olmec Dragon: A Study in Pre- Columbian Iconography”, en H. B. 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Symbolic Notation of Teotihuacan: Elements of Writing in a Mesoamerican Culture of the Classic Period, BAR International Series, 313, Oxford.Lischka, J. 1978. “A Functional Analysis of Middle Classic Ceramics at Kaminaljuyu”, en R. Wetherington (ed.), The Ceramics of Kaminaljuyu, Guatemala, Pennsylvania State University Press Monograph Series on Kaminaljuyu, pp. 223-278.Longyear, J. 1952. Copan Ceramics; A Study of Southeastern Maya Pottery, Carnegie Institution of Washington Pub. 597, Washington D.C., Carnegie Institution.Marcus, J. 1976. “The Iconography of Militarism at Monte Alban and Neighboring Sites in the Valleys of Oaxaca”, en H. B. Nicholson (ed.), Origins of Religious Art and Iconography in Preclassic Mesoamerica, UCLA Latin American Studies Series, vol. 31. Los Angeles, The Ethnic Arts Council of Los Angeles, pp. 123-140.Marcus, J., K. Flannery, y R. Spores 1983. “The Cultural Legacy of the Oaxacan Preceramic”, en K. Flannery y J. 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    Effects of habitat isolation and predation pressure on an arboreal food-web

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    Habitat isolation is expected to reduce population densities of animals via reduced immigration. However, altered trophic interactions in isolated habitats may modify these effects, especially since the strength of isolation effects is expected to increase with trophic rank. Here, we studied effects of habitat isolation on a food-web module consisting of herbivorous beetles, predatory spiders, spider-preying wasps and arthropod-feeding birds. We compare two systems that were studied in subsequent years: a study on 29 mature apple orchards that varied in the degree of isolation from forest, and a study on 20 groups of newly planted cherry trees that showed similar variation in their degree of habitat isolation. No birds were observed on the young fruit trees. Wasps and spiders showed the expected lower abundances in isolated habitats. On mature trees, birds were present and showed lower abundances in isolated habitats. Wasps were reduced to a similar degree by habitat isolation as on the young trees. Surprisingly, spider densities on the mature trees were higher in isolated than in connected habitat. This contrasting response of spiders to habitat isolation is likely to be due to release from bird predation in isolated mature orchards. In both study systems, beetles showed no significant effect of habitat isolation. Our results confirm that the sensitivity to fragmentation increases with trophic rank, and suggest that trophic interactions should receive more attention in fragmentation studies.Swiss National Science foundation [3100A0-114058

    Developmental Regulation of Small-Conductance Ca²⁺-Activated K⁺ Channel Expression and Function in Rat Purkinje Neurons

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    Calcium transients play an important role in the early and later phases of differentiation and maturation of single neurons and neuronal networks. Small-conductance calcium-activated potassium channels of the SK type modulate membrane excitability and are important determinants of the firing properties of central neurons. Increases in the intracellular calcium concentration activate SK channels, leading to a hyperpolarization of the membrane potential, which in turn reduces the calcium inflow into the cell. This feedback mechanism is ideally suited to regulate the spatiotemporal occurrence of calcium transients. However, the role of SK channels in neuronal development has not been addressed so far. We have concentrated on the ontogenesis and function of SK channels in the developing rat cerebellum, focusing particularly on Purkinje neurons. Electrophysiological recordings combined with specific pharmacological tools have revealed for the first time the presence of an afterhyperpolarizing current (I_{AHP}) in immature Purkinje cells in rat cerebellar slices. The channel subunits underlying this current were identified as SK2 and localized by in situ hybridization and subunit-specific antibodies. Their expression level was shown to be high at birth and subsequently to decline during the first 3 weeks of postnatal life, both at the mRNA and protein levels. This developmental regulation was tightly correlated with the expression of I_{AHP} and the prominent role of SK2 channels in shaping the spontaneous firing pattern in young, but not in adult, Purkinje neurons. These results provide the first evidence of the developmental regulation and function of SK channels in central neurons

    Auditoría energética en una microcervecería.

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    Proyecto Final Integrador de IngenieríaEn el siguiente trabajo, se realizó una evaluación energética de una microcervecería localizada en el Parque Industrial Buen Ayre, Zona Oeste del Gran Buenos Aires, Argentina. Para ello, se siguieron los lineamientos definidos por la norma ISO 50.001 de Sistemas de Gestión de la Energía, particularmente el apartado referente a la revisión energética. A su vez, se utilizó el modelo de auditoría energética de nivel 1, descripto en la norma ISO 50.002.Fil: Stocker, Ignacio. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Buenos Aires, Argentin

    Seismic Protection of Automated Stocker System by Customized Viscous Fluid Dampers

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    The hi-tech industries in the Science Park at southern Taiwan were heavily damaged by a strong earthquake early 2016. The financial loss in this event was attributed primarily to the automated stocker system handling fully processed products, and recovery of the automated stocker system from the aftermath proved to contribute major lead time. Therefore, development of effective means for protection of stockers against earthquakes has become the highest priority for risk minimization and business continuity. This study proposes to mitigate the seismic response of the stockers by introducing viscous fluid dampers in between the ceiling and the top of the stockers. The stocker is expected to vibrate less violently with a passive control force on top. Linear damper is considered in this application with an optimal damping coefficient determined from a preliminary parametric study. The damper is small in size in comparison with those adopted for building or bridge applications. Component test of the dampers has been carried out to make sure they meet the design requirement. Shake table tests have been further conducted to verify the proposed scheme under realistic earthquake conditions. Encouraging results have been achieved by effectively reducing the seismic responses of up to 60% and preventing the FOUPs from falling off the shelves that would otherwise be the case if left unprotected. Effectiveness of adopting a viscous fluid damper for seismic control of the stocker on top against the ceiling has been confirmed. This technique has been adopted by Macronix International Co., LTD for seismic retrofit of existing stockers. Demonstrative projects on the application of the proposed technique are planned underway for other companies in the display industry as well

    Spatially-localized time dependent solutions including turbulence and their interactions in 2D Kolmogorov flow

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    In 2D Kolmogorov flow in small aspect ratio domains, spatially-localized solutions such as kink, traveling or time-dependent kink-antikink pars coexist. However, the conservation of the flow rate in the y direction strongly restrict combination of localized solutions and their positioning. We find that by adding a homogeneous flow U y their positioning is controlled and each of localized solutions including a spatially-localized chaos is isolated. Numerical results suggest that these isolated solutions can be elements constructing a whole flow

    Characteristics of overlap region in high-Reynolds number turbulent channel flow

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    Direct numerical simulation of the fully developed turbulent channel flows have been carried out at the Reynolds number based on the friction velocity and the channel half width, 2000, 4000 and 8000. A hybrid 10th order accurate finite difference scheme in the stream and spanwise directions, and a second-order scheme in the wall-normal direction is adapted as the spatial discretization method. We observed the plateau profiles in the indicator function corresponded to the von Karman constant. Furthermore, second peak of streamwise pre-multiplied spectra were appeared in the same wall normal height, 300 < y+ < 600, in case of Re = 4000. Nevertheless, the effects of the lager than the channel half height scale on the streamwise turbulent intensity are fixed contributions without dependence on Reynolds number. These results suggested that the new streamwise vortexes are formed between buffer layer and outer layer with increasing of Reynolds number
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