5,881 research outputs found
HEDONIC ESTIMATION OF SOUTHEASTERN OKLAHOMA FORESTLAND PRICES
Forestland is a composite good, the price of which varies with its characteristics, such as its ability to produce timber and its proximity to markets. Sales of predominately forested land in southeastern Oklahoma were examined to better understand and quantify the influences of physical and spatial characteristics on sales prices.Land Economics/Use,
Farmers’ Valuation of Incentives to Produce GMO-free Milk: A Discrete Choice Experiment
This paper investigates farmers’ willingness to adopt a Genetically Modified Organisms (GMO)-free milk production scheme introduced by the dairy. Incentives like a price premium, advice, quality control and feed procurement are set to encourage the conversion. The analysis is based upon Discrete Choice Experiments with 151 dairy farmers in Germany. Alternative-specific conditional logit estimation reveals the marginal effects of incentives and the amount of compensation. The results indicate that attributes like the price premium, takeover of feed procurement and an external audit affect the likelihood of adoption. Farmer, farm characteristics and attitudes concerning GMO as well as expectations on feed prices were found to be significant determinants of adoption. Moreover the findings demonstrate variation in the values of attributes across regions
Coordinated neuronal ensembles in primary auditory cortical columns.
The synchronous activity of groups of neurons is increasingly thought to be important in cortical information processing and transmission. However, most studies of processing in the primary auditory cortex (AI) have viewed neurons as independent filters; little is known about how coordinated AI neuronal activity is expressed throughout cortical columns and how it might enhance the processing of auditory information. To address this, we recorded from populations of neurons in AI cortical columns of anesthetized rats and, using dimensionality reduction techniques, identified multiple coordinated neuronal ensembles (cNEs), which are groups of neurons with reliable synchronous activity. We show that cNEs reflect local network configurations with enhanced information encoding properties that cannot be accounted for by stimulus-driven synchronization alone. Furthermore, similar cNEs were identified in both spontaneous and evoked activity, indicating that columnar cNEs are stable functional constructs that may represent principal units of information processing in AI
Characterization of the ZFX family of transcription factors that bind downstream of the start site of CpG island promoters
Our study focuses on a family of ubiquitously expressed human C₂H₂ zinc finger proteins comprised of ZFX, ZFY and ZNF711. Although their protein structure suggests that ZFX, ZFY and ZNF711 are transcriptional regulators, the mechanisms by which they influence transcription have not yet been elucidated. We used CRISPR-mediated deletion to create bi-allelic knockouts of ZFX and/or ZNF711 in female HEK293T cells (which naturally lack ZFY). We found that loss of either ZFX or ZNF711 reduced cell growth and that the double knockout cells have major defects in proliferation. RNA-seq analysis revealed that thousands of genes showed altered expression in the double knockout clones, suggesting that these TFs are critical regulators of the transcriptome. To gain insight into how these TFs regulate transcription, we created mutant ZFX proteins and analyzed them for DNA binding and transactivation capability. We found that zinc fingers 11–13 are necessary and sufficient for DNA binding and, in combination with the N terminal region, constitute a functional transactivator. Our functional analyses of the ZFX family provides important new insights into transcriptional regulation in human cells by members of the large, but under-studied family of C₂H₂ zinc finger proteins
Technical development to improve satellite sounding over radiatively complex terrain
High resolution topography was acquired and applied on the McIDAS system. A technique for finding the surface skin temperature in the presence of cloud and reflected sunlight was implemented in the ALPEX retrieval software and the variability of surface emissivity at microwave wavelength was examined. Data containing raw radiances for all HIRS and MSU channels for NOAA-6 and 7 were used. METEOSAT data were used to derive cloud drift and water vapor winds over the Alpine region
Conversations on an Embedded Phone While Driving: Predicted vs. Observed Real-World Airbag Deployment Crash Rates
OBJECTIVE To evaluate hypotheses that may help explain the discrepancy between the predicted vs. observed real-world airbag-deployment crash rates during conversation on a mobile phone embedded in a vehicle. METHOD Previous epidemiological, laboratory, and closed-road studies predict a 2-8 times increase in relative risk of phone conversations during real-world driving compared to baseline driving. Counts of real-world crashes clearly associated with portable cell usage are difficult to obtain and incomplete. However a large and complete body of real-world data exists of conversation usage on mobile phones embedded in vehicles and crashes severe enough to deploy an airbag (Young, 2001). The degree of discrepancy between the observed numbers of real-world crashes in these studies and the predicted risks of wireless conversations from previous studies is calculated. Hypotheses are presented and evaluated that may help to explain the discrepancy. RESULTS The absolute frequency of airbag deployment crashes occurring during conversation on a wireless phone embedded in a vehicle is low, and the relative airbag deployment crash rate is no greater than baseline driving. The pros and cons of five hypotheses are evaluated to help explain the discrepancy from previous studies predicting an increased crash rate from wireless phone conversations in general: (1) the reaction time increase arising from conversations in previous studies may be too small to give rise to a detectable increase in real-world crash rates; (2) labbased event detection does not account fully for similar types of event detection in real driving, let alone for crashes (Angell et al., 2006; Curry et al., 2005; Young et al., 2005); (3) conversation may at times mitigate risks such as fatigue; (4) portable and embedded cell phones may have substantially different human factor properties; and (5) drivers may tend to change behavior during calls in ways that reduce net risk: place calls in relatively benign driving conditions, reduce risky driving maneuvers, increase headway, glance longer to the forward roadway, increase glances to mirrors after an event. CONCLUSIONS The observed real-world airbag-deployment crash rate during conversations on an embedded hands-free device is substantially lower than predicted by previous simulator, closed-road, or epidemiological studies. Several hypotheses, if validated, may help resolve the discrepancy. REFERENCES Angell, L.S., Auflick, L.L., Austria, P.A., Kochhar, D.S. & Tijerina, L. (2006). Driver workload metrics project: Task 2 final report. Submitted to U.S. Dept. of Transportation, FHA, & NHTSA under Cooperative Agreement Number DTFH61-01-X-00014. Curry, R.C., Greenberg, J.A., & Kiefer, R.J. (2005). NADS versus CAMP closed-course comparison examining ‘last second’ braking and steering maneuvers under various kinematic conditions. Crash Avoidance Metrics Partnership (CAMP), Contract DTFH61-01-X-00014, Washington, DC, August, DOT HS 809 925. Young, R. (2001). Association between embedded cellular phone calls and vehicle crashes involving air bag deployment. Proceedings of Driving Assessment 2001: International Symposium on Human Factors in Driver Assessment, Training and Vehicle Design, Snowmass, Utah, August, 390-400. Young, R.A., Aryal, B.J., Muresan, M., Ding, X., Oja, S. & Simpson, S. (2005). Road-to-lab: Validation of the Static Load Test for predicting on-road driving performance while using advanced in-vehicle information and communication devices. Proceedings of the Third International Driving Symposium on Human Factors in Driver Assessment, Training and Vehicle Design, Rockport, Maine, July, 240-25
Investigation of the Periodic Magnetic Field Modulation Inside Apertures of LHC Superconducting Dipole Models
The windings of high-field accelerator magnets are usually made of Rutherford-type superconducting cables. The magnetic field distribution along the axis of such magnets exhibits a pronounced periodic modulation with a wavelength equal to the twist pitch length of the cable used in the winding. Such an effect, resulting from quasi-persistent currents, was investigated with a Hall probe array inserted inside the aperture of 1-metre long LHC superconducting dipole models. The amplitude and the time dependence of this periodic field oscillation have been studied as a function of the transport current history. The impact on the magnet stability of the non-uniform current redistribution producing such a field modulation is discussed
Culturas intercalares de milho (Zea mays L.) em reflorestamentos de Pinus taeda L. no sul do Paraná.
Este trabalho foi planejado com o objetivo de se avaliar, na região dos Campos Gerais do Paraná, o rendimento de associações de Pinus taeda L. com milho (Zea mays L.), em função de três densidades populacionais desta cultura: 50 mil, 67 mil e 83 mil plantas/ha, dispostas, respectivamente, em duas, três e quatro linhas, entre as linhas do Pinus plantado no espaçamento de 3 x 2 m. O plantio do Pinus e o da primeira cultura de milho foram efetuados no ano agrícola 1981/82; duas novas culturas de milho foram plantadas em 1982 e em 1983. Até a terceira colheita do milho, não se registraram diferenças entre as sobrevivências do Pinus associado com duas, três e quatro linhas do cereal, nem entre estas e as da testemunha sem consórcio (média de 91,33%). Quanto à altura e ao diâmetro da espécie florestal, no entanto, os incrementos registrados no consórcio com quatro linhas de milho (3,65 m e 5,73 cm) foram menores que na testemunha sem consórcio (4,17 m e 6,92 cm), enquanto que nos consórcios com duas e três linhas, estes ficaram em posição intermediária. As produções de milho, no primeiro e no segundo ano, propiciaram, respectivamente, retornos sobre o capital investido nesta cultura, da ordem de 135 e 94%. Já no terceiro ano, quando o desenvolvimento do Pinus tornou-se suficiente para sombrear parcialmente a cultura agrícola, sua produção foi deficitária, embora em pequeno grau. A população de 50 mil plantas de milho por hectare, dispostas em duas linhas, entre as linhas do Pinus, mostrou-se a mais indicada para o sistema
Investigation of the Periodic Magnetic Field Modulation in LHC Superconducting Dipoles
The windings of high-field accelerator magnets are usually made of Rutherford-type superconducting cables. The magnetic field distribution along the axis of such magnets exhibits a periodic modulation with a wavelength equal to the twist pitch length of the cable used in the winding. This effect, resulting from quasi-persistent currents, was investigated with a Hall probes array inserted inside the aperture of the LHC superconducting dipoles, both in short models and full-scale prototypes. The amplitude and the time dependence of this periodic field oscillation have been studied as a function of the magnet current history. The origin and the impact on the LHC dipoles stability of the non-uniform current redistribution producing such a field modulation are discussed
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