4,385 research outputs found

    Wheat Productivity Estimates Using LANDSAT Data

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    The author has identified the following significant results. The biological leaf area index data show that there can be large variations in field vegetative condition from point to point. This is especially true in flood-irrigated fields, in which plant density (and development) varies drastically between rows that are in channels vs. those that are in raised areas. Considerable care must be used in interpreting the significance of isolated leaf area index measurements made from a single wheat row

    Application of LANDSAT system for improving methodology for inventory and classification of wetlands

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    There are no author-identified significant results in this report

    Protein sectors: statistical coupling analysis versus conservation

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    Statistical coupling analysis (SCA) is a method for analyzing multiple sequence alignments that was used to identify groups of coevolving residues termed "sectors". The method applies spectral analysis to a matrix obtained by combining correlation information with sequence conservation. It has been asserted that the protein sectors identified by SCA are functionally significant, with different sectors controlling different biochemical properties of the protein. Here we reconsider the available experimental data and note that it involves almost exclusively proteins with a single sector. We show that in this case sequence conservation is the dominating factor in SCA, and can alone be used to make statistically equivalent functional predictions. Therefore, we suggest shifting the experimental focus to proteins for which SCA identifies several sectors. Correlations in protein alignments, which have been shown to be informative in a number of independent studies, would then be less dominated by sequence conservation.Comment: 36 pages, 17 figure

    A Meaner, More Callous Digital World for Youth? The Relationship Between Violent Digital Games, Motivation, Bullying and Civic Behavior amongst Children

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    The relationship between violent digital games and youth behavior remains contested in the scholarly literature. To date considerable scholarship has focused on university students with fewer studies of adolescents or children. The current study examines correlational relationships between violent game exposure and bullying behaviors, antisocial attitudes, civic attitudes and civic behaviors in a sample of 304 children from the United Kingdom (Mean age = 12.81). The paper also considered motivational influences on use of violent digital games. Results indicated that violent game exposure did not correlate meaningfully with either antisocial or civic behaviors or attitudes. These results are discussed in a motivational and developmental context

    Modeling of transient heat pipe operation

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    The overall goal is to gain a better understanding of the transient behavior of heat pipes operating under both normal and adverse conditions. Normal operation refers to cases where the capillary structure remains fully wetted. Adverse operation occurs when drying, re-wetting, choking, noncontinuum flow, freezing, thawing etc., occur within the heat pipe. The work was redirected towards developing the capability to predict operational behavior of liquid metal heat pipes used for cooling aerodynamic structures. Of particular interest is the startup of such heat pipes from an initially frozen state such as might occur during re-entry of a space vehicle into the Earth's atmosphere or during flight of hypersonic aircraft

    Yield prediction by analysis of multispectral scanner data

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    A preliminary model describing the growth and grain yield of wheat was developed. The modeled growth characteristics of the wheat crop were used to compute wheat canopy reflectance using a model of vegetation canopy reflectance. The modeled reflectance characteristics were compared with the corresponding growth characteristics and grain yield in order to infer their relationships. It appears that periodic wheat canopy reflectance characteristics potentially derivable from earth satellites will be useful in forecasting wheat grain yield

    Development of an Emulation-simulation Thermal Control Model for Space Station Application

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    Analysis techniques to evaluate the effects of changing thermal loads and the methods utilized to control temperature distributions in the orbital space station are essential. Analysis techniques including a user-friendly computer program, were developed which should prove useful in thermal design and system analysis of the the space station. The program uses a data base and user input to compute costs, sizes, and power requirements for individual components and complete systems. User input consists of selecting mission parameters, selecting thermal acquisition configurations, transport systems and distances, and thermal rejection configurations

    Modeling of Transient Heat Pipe Operation

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    The major goal of this project is to develop mathematical models of heat pipes which can be used to predict transient behavior under normal and adverse conditions. The models and solution techniques are to be formulated so that they can be incorporated into existing NASA structural design codes. The major parameters of interest are heat flux distribution, temperature distribution, working fluid pressure distribution, fluid and containment thermal and mechanical properties and geometry. Normal transient operation is taken to be operating conditions where the capillary structure remains fully wetted. Adverse transient operation occurs when drying, re-wetting, choking, non-continuum flow, thawing, freezing, etc., occur in the internal heat pipe working fluid

    Lack of Consensus Among Scholars on the Issue of Video Game “Addiction”

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    Whether pathological video game overuse constitutes a distinct mental disorder remains an issue of controversy among scholars. Both empirical data and scholarly opinions differ regarding the status of pathological gaming and whether “addiction” is the best frame by which to understand video game use. The current study sought to examine the status of scholarly opinions in a survey of 214 scholars to examine their opinion of possible behavioral effects of games. Results indicated a variance of opinions. About 60.8% of scholars agreed pathological gaming could be a mental health problem, whereas 30.4% were skeptical. However, only 49.7% believed the DSM criteria for “internet gaming disorder” were valid, with slightly higher numbers, 56.5%, supporting the World Health Organization “gaming disorder” diagnosis. More scholars worried about both the DSM and WHO criteria over-pathologizing normal youth than weren’t worried about this. Scholars were likewise split over whether the DSM/WHO had precipitated moral panics over video games. Belief in pathological gaming was positively predicted by hostile attitudes toward children and negatively by participants’ experience with games. Overall results indicated continued significant disagreements among scholars related to pathological gaming. Claims of consensus are, at this juncture, likely prematur
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