Solar driven lasers for power satellite applications

The technological feasibility of using multimagawatt lasers for space power transmission is discussed. Candidate lasers include electric discharge lasers, direct optically pumped lasers, and free electron lasers

South Dakota Grasslands, Their Condition and Management

Statewide surveys of South Dakota grasslands have been made in 1940, 1942, and 1946. The stocking rates presented on the map (center pages) were determined from the 1946 survey, based upon the past ten years\u27 actual use-grazing records from representative farms and ranches. The range and pasture condition method of study was introduced into the 1946 resurvey of South Dakota grassland. The condition approach is much more usable by stockmen and agricultural workers alike than former methods of making grassland inventories. The 1946 inventory of range and pasture condition shows South Dakota grasslands are near the peak of productivity. Above-average rainfall is largely responsible for this condition. When the precipitation cycle becomes less favorable and dry years come and they surely will-then only good management of our grasslands can maintain their productivity and prevent the unfavorable conditions of the mid-thirties. Further studies and follow-up surveys will be made periodically to keep abreast of changes in condition and stocking rates for South Dakota grassland

Evaluating remote sensing of deciduous forest phenology at multiple spatial scales using PhenoCam imagery

Plant phenology regulates ecosystem services at local and global scales and is a sensitive indicator of global change. Estimates of phenophase transition dates, such as the start of spring or end of autumn, can be derived from sensor-based time series data at the near-surface and remote scales, but must be interpreted in terms of biologically relevant events. We use the PhenoCam archive of digital repeat photography to implement a consistent protocol for visual assessment of canopy phenology at 13 temperate deciduous forest sites throughout eastern North America, as well as to perform digital image analysis for time series-based estimates of phenology dates. We then compare these near-surface results to remote sensing metrics of phenology at the landscape scale, derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Advanced Very High Resolution Radiometer (AVHRR) sensors. We present a new type of curve fit, using a generalized sigmoid, to estimate phenology dates. We quantify the statistical uncertainty of phenophase transition dates estimated using this method and show that the generalized sigmoid results in less statistical uncertainty than other curve-fitting methods. Additionally, we find that dates derived from analysis of high-frequency PhenoCam imagery have smaller uncertainties than remote sensing metrics of phenology, and that dates derived from the remotely-sensed enhanced vegetation index (EVI) have smaller uncertainty than those derived from the normalized difference vegetation index (NDVI). Near-surface time series estimates for the start of spring are found to closely match visual assessment of leaf out, as well as remote sensing-derived estimates of the start of spring. However late spring and autumn phenology exhibit larger differences between near-surface and remote scales. Differences in late spring phenology between near-surface and remote scales are found to correlate with a landscape metric of deciduous forest cover. These results quantify the effect of landscape heterogeneity when aggregating to the coarser spatial scales of remote sensing, and demonstrate the importance of accurate curve fitting and vegetation index selection when analyzing and interpreting phenology time series.Organismic and Evolutionary Biolog

Beef cows and calves, 1979: a summary of research

Response of fall-born calves to monensin on orchardgrass / alfalfa or tall fescue / alfalfa pastures / F. M. Byers, C. F. Parker, and R. W. Van Keuren -- Effects of forage system and breed type on the performance of fall calving cows / C. F. Parker and R. W. Van Keuren -- Forage management for beef production / R. W. Van Keuren, C. F. Parker, and E. W. Klosterman -- Breeding and management systems to optimize beef breeding herd productivity / E. W. Klosterman, R. W. Van Keuren, C. F. Parker, and F. M. Byers -- Voluntary feed intake of mature cows as related to breed type, condition, and forage quality / E. W. Klosterman, F. M. Byers, and C. F. Parker -- Weight and condition changes of pregnant beef cows wintered on corn stover stacks / G. R. Wilson, J. G. Gordon, J. H. Cline, K. M. Irvin, and E. W. Klosterman -- Estrus synchronization of beef cows and heifers with prostaglandin F2a under field conditions / G. R. Wilson, T. L. Benecke, K. M. Irvin, T. M. Ludwick, C. E. Marshall, and R. A. Wallac

Deriving the number of jobs in proximity services from the number of inhabitants in French rural municipalities

We use a minimum requirement approach to derive the number of jobs in proximity services per inhabitant in French rural municipalities. We first classify the municipalities according to their time distance to the municipality where the inhabitants go the most frequently to get services (called MFM). For each set corresponding to a range of time distance to MFM, we perform a quantile regression estimating the minimum number of service jobs per inhabitant, that we interpret as an estimation of the number of proximity jobs per inhabitant. We observe that the minimum number of service jobs per inhabitant is smaller in small municipalities. Moreover, for municipalities of similar sizes, when the distance to the MFM increases, we find that the number of jobs of proximity services per inhabitant increases.Comment: 6 pages, 5 figure