North American Vegetation Dynamics Observed with Multi-Resolution Satellite Data

North American vegetation has been discovered to be a net carbon sink, with atypical behavior of drawing down more carbon from the atmosphere during the past century. It has been suggested that the Northern Hemisphere will respond favorably to climate warming by enhancing productivity and reducing the impact of fossil fuel emissions into the atmosphere. Many investigations are currently underway to understand and identify mechanisms of storage so they might be actively managed to offset carbon emissions which have detrimental consequences to the functioning of ecosystems and human well being. This paper used a time series of satellite data from multiple sensors at multiple resolutions over the past thlrty years to identify and understand mechanisms of change to vegetation productivity throughout North America. We found that humans had a marked impact to vegetation growth in half of the six selected study regions which cover greater than two million km2. We found climatic influences of increasing temperatures, and longer growing seasons with reduced snow cover in the northern regions of North America with forest fire recovery in the Northern coniferous forests of Canada. The Mid-latitudes had more direct land cover changes induced by humans coupled with climatic influences such as severe drought and altered production strategies of rain-fed agriculture in the upper Midwest, expansion of irrigated agriculture in the lower Midwest, and insect outbreaks followed by subsequent logging in the upper Northeast. Vegetation growth over long time periods (20+ years) in North America appears to be associated with long term climate change but most of the marked changes appear to be associated with climate variability on decadal and shorter time scales along with direct human land cover conversions. Our results document regional land cover land use change and climatic influences that have altered continental scale vegetation dynamics in North America

Review of \u27Republican Theology: The Civil Religion of American Evangelicals\u27

Although I find Lynerd’s characterization of the Christian Right unpersuasive (for reasons explained below), Republican Theology nonetheless performs a valuable service in highlighting the reciprocal influence of religious and political ideas, particularly in the early years of the republic... Lynerd makes a strong case that American evangelicals, while aware of the potential for tension, viewed each commitment as indispensable to the formation of a Godly republic

The Relationship Between the Relative Legibility of Textual Material and Resolving Power in a Microphotographic System

The application of microphotographic methods for the processing and storage of information has grown steadily during the last two decades. The microphotographic system, through which the information must pass at a minimum is as follows: Step 1: Photographing of the original document at a large reduction onto a silver halide microfilm. Step 2: Duplicating through contact printing onto a non-silver photographic material. Step 3: Second generation duplication onto a nonsilver photographic material (This image may be used on a microfilm reader). Step 4: Enlargement of the second generation duplicate to give a hard copy print. One of the main objectives of this system is the production of a legible image at the end of the process. As the steps mentioned above indicate, the creation of the original negative at a large reduction is the first major step and critical to the success of future steps in the process. A mistake in camera exposure at this point may well cause an illegible image to be produced at the end of the system. A technique long utilized by the microfilm industry for the measurement of small scale image quality of greatly reduced images is resolution in lines per millimeter. The purpose of this experiment is to determine the relationship between resolution and legibility for similarly produced original negatives. The methodology of the experiment consisted of producing original negatives in a conventional microphotographic system at 24x reduction of two types of resolution test targets. The NBS 10-10 (100:1 contrast) test chart and the R.I.T. alphanumeric (100:1 and 8:1 contrast) test objects v/ere the three targets used. The three targets were photographed at eight equally spaced exposure levels with a total ratio of 10:1. Replicate images were made at each exposure level. The resolution measurements were read from an 80x microscope and from a microfilm reader at 24x by this author. A series of standard documents in two different type faces (ten point serif and sanserif) were exposed and processed in the same manner as the resolution targets. Replicate sets were made at each exposure level. The standard documents consisted of meaningful, continuous, textual material. The original negatives of these standard documents were evaluated for their legibility by placing them in a microfilm reader (24x) and determining the distance at which the images became legible. Fifteen observers were employed. The average distance measurements were used to determine the relative legibility of the original negatives. A two- factor ANOVA at an alpha risk of 0.05 indicated that type face did not affect the relative legibility of the negatives. Camera exposure level was found to be significant, which means that images of varying legibility were produced. The functional relationships between resolution from the three targets versus camera exposure level and between relative legibility versus camera exposure level were determined and found to fit second-order models. The optimum camera exposure for both measures of image quality were less than one-third of a stop apart. The correlation between resolution and relative legibility was high in all cases (minimum of .86) and significant at the 0.01 level. A linear model best fits these functional relationships. The R.I.T. 8:1 contrast target provided the highest correlation with r equal to O.96. The NBS and R.I.T. test charts were very similar in the resolution measurements obtained from each. However, when a secondary observer\u27s measurements were compared to this author\u27s the between observer differences in resolution values for the NBS target were nearly four times as large as the differences on the R.I.T. target. In summary, the camera exposure of the original negative that provides the highest resolution in a microfilm system will also be very close to the exposure that yields the optimum legibility for commonly employed type styles and sizes. The resolution measurements can be obtained directly from the microfilm reader that is a part of the system. If the R.I .T. 8:1 contrast target is used the legibility predictions will have a high level of accuracy and excel lent precision