35,903 research outputs found

    European Railway Comparisons: Final Report

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    The Institute for Transport Studies (ITS), University of Leeds and the British Railways Board (BRB) carried out a major comparative study of Western European railways in the late 1970s (BRB and University of Leeds, 1979). Follow-up work was carried out by ITS financed by the Social Science Research Council and reported by Nash (1985). It was deaded to revive this work at ITS for a number of reasons: It is over ten years since the last set of comparisons (for 1981) were made at ITS and therefore a review of the changes in costs and productivity may be timely. There has been a number of technical developments that make the use of statistical cost analysis more promising. These developments include the use of more flexible functional forms such as the translog, and the development of comprehensive total factor productivity indices (see, for example, Dodgson, 1985 and, more recently, Hensher and Waters, 1993). There is increasing interest in the organisational structure of railway industries as a result of the 1988 Transport Act in Sweden, the EC directive 91/4-40 and the publication of proposals for privatising British Rail in July 1992 (see, for example, ECMT, 1993). Given the explosion in information technology, there were some hopes that data availability would have improved. (Continues..

    Industrial Coal Demand in China: A Provincial Analysis

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    The general concern on the environmental implications of the rising demand for coal registered in China during the last few years has induced considerable research effort to produce accurate forecasts of China’s energy requirements. Nevertheless, no previous study has modelled the coal demand in China at provincial level. The aim of this paper is twofold. First, we estimate and forecast the Chinese demand for coal using panel data disaggregated by provinces and accounting for spatial heterogeneity. Second, given the spatial nature of the data, we explicitly capture the spatial autocorrelation among provinces using spatial econometrics. In particular, we specify the Chinese industrial coal demand at provincial level with a fixed-effect spatial lag model and a fixed-effect spatial error model. The fixedeffect spatial lag model seems to better capture the existing interdependence between provinces. This model forecasts an average annual increase in coal demand to 2010 of 4 percent.Energy demand in China, Coal demand in China, Chinese provinces, Panel data; Spatial econometrics, Forecasting

    THE DIFFUSION OF LIVESTOCK BREEDING TECHNOLOGY IN THE U.S.: OBSERVATIONS ON THE RELATIONSHIP BETWEEN TECHNICAL CHANGE AND INDUSTRY STRUCTURE

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    Livestock Production/Industries, Research and Development/Tech Change/Emerging Technologies,

    Multi-temporal evaluation of soil moisture and land surface temperature dynamics using in situ and satellite observations

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    Soil moisture (SM) is an important component of the Earth’s surface water balance and by extension the energy balance, regulating the land surface temperature (LST) and evapotranspiration (ET). Nowadays, there are two missions dedicated to monitoring the Earth’s surface SM using L-band radiometers: ESA’s Soil Moisture and Ocean Salinity (SMOS) and NASA’s Soil Moisture Active Passive (SMAP). LST is remotely sensed using thermal infrared (TIR) sensors on-board satellites, such as NASA’s Terra/Aqua MODIS or ESA & EUMETSAT’s MSG SEVIRI. This study provides an assessment of SM and LST dynamics at daily and seasonal scales, using 4 years (2011–2014) of in situ and satellite observations over the central part of the river Duero basin in Spain. Specifically, the agreement of instantaneous SM with a variety of LST-derived parameters is analyzed to better understand the fundamental link of the SM–LST relationship through ET and thermal inertia. Ground-based SM and LST measurements from the REMEDHUS network are compared to SMOS SM and MODIS LST spaceborne observations. ET is obtained from the HidroMORE regional hydrological model. At the daily scale, a strong anticorrelation is observed between in situ SM and maximum LST (R ˜ -0.6 to -0.8), and between SMOS SM and MODIS LST Terra/Aqua day (R ˜ - 0.7). At the seasonal scale, results show a stronger anticorrelation in autumn, spring and summer (in situ R ˜ -0.5 to -0.7; satellite R ˜ -0.4 to -0.7) indicating SM–LST coupling, than in winter (in situ R ˜ +0.3; satellite R ˜ -0.3) indicating SM–LST decoupling. These different behaviors evidence changes from water-limited to energy-limited moisture flux across seasons, which are confirmed by the observed ET evolution. In water-limited periods, SM is extracted from the soil through ET until critical SM is reached. A method to estimate the soil critical SM is proposed. For REMEDHUS, the critical SM is estimated to be ~0.12 m3/m3 , stable over the study period and consistent between in situ and satellite observations. A better understanding of the SM–LST link could not only help improving the representation of LST in current hydrological and climate prediction models, but also refining SM retrieval or microwave-optical disaggregation algorithms, related to ET and vegetation status.Peer ReviewedPostprint (published version

    Average seasonal changes in chlorophyll a in Icelandic waters

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    The standard algorithms used to derive sea surface chlorophyll a concentration from remotely sensed ocean colour data are based almost entirely on the measurements of surface water samples collected in open sea (case 1) waters which cover ~60% of the worlds oceans, where strong correlations between reflectance and chlorophyll concentration have been found. However, satellite chlorophyll data for waters outside the defined case 1 areas, but derived using standard calibrations, are frequently used without reference to local in situ measurements and despite well-known factors likely to lead to inaccuracy. In Icelandic waters, multiannual averages of 8-d composites of SeaWiFS chlorophyll concentration accounted for just 20% of the variance in a multiannual dataset of in situ chlorophyll a measurements. Nevertheless, applying penalized regression spline methodology to model the spatial and temporal patterns of in situ measurements, using satellite chlorophyll as one of the predictor variables, improved the correlation considerably. Day number, representing seasonal variation, accounted for substantial deviation between SeaWiFS and in situ estimates of surface chlorophyll. The final model, using bottom depth and bearing to the sampling location as well as the two variables mentioned above, explained 49% of the variance in the fitting dataset

    European Investment Bank 25 Years: 1958-1983

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    How Polycentric is a Monocentric City? The Role of Agglomeration Economies

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    Can the demise of the monocentric economy across cities during the 20th century be explained by decreasing transport costs to the city center or are other fundamental forces at work? Taking a hybrid perspec¬tive of classical bid-rent theory and a world where clustering of economic activity is driven by (knowledge) spillovers, Berlin, Germany, from 1890 to 1936 serves as a case in point. We assess the extent to which firms in an environment of decreasing transport costs and industrial transformation face a trade-off between distance to the CBD and land rents and how agglomeration economies come into play in shaping their location deci¬sions. Our results suggest that an observable flattening of the traditional distance to the CBD gradient may mask the emergence of significant agglomeration economies, especially within predominantly service-based inner city districts.Transport Innovations, Land Values, Location Productivity, Agglomeration Economies, Economic History, Berlin.

    Modeling the Vertical Distributions of Downwelling Plane Irradiance and Diffuse Attenuation Coefficient in Optically Deep Waters

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    The diffuse attenuation coefficient Kᵈ is critical to understand the vertical distribution of underwater downwelling irradiance (Eᵈ). Theoretically Eᵈ is composed of the direct solar beam and the diffuse sky irradiance. Applying the statistical results from Hydrolight radiative transfer simulations, Kᵈ is expressed into a mathematical equation (named as PZ06) integrated from the contribution of direct solar beam and diffuse sky irradiance with the knowledge of sky and water conditions. The percent root mean square errors (RMSE) for the vertical distribution of Eᵈ(z) under various sky and water conditions between PZ06 and Hydrolight results are typically less than 4%. Field observations from the southern Middle Atlantic Bight (SMAB) and global in situ data set (NOMAD) also confirmed the validity of PZ06 in reproducing Kᵈ. PZ06 provides an alternative and improvement to the simpler models (e. g., Gordon, 1989; and Kirk, 1991) and an operational ocean color algorithm, while the latter two kinds of models are valid to limited sky and water conditions. PZ06 can be applied to study Kᵈ from satellite remotely sensed images and seems to improve Kᵈ derivation over current operational ocean color algorithm
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