Gaussian process convolutions for Bayesian spatial classification

Master's Project (M.S.) University of Alaska Fairbanks, 2016We compare three models for their ability to perform binary spatial classification. A geospatial data set consisting of observations that are either permafrost or not is used for this comparison. All three use an underlying Gaussian process. The first model considers this process to represent the log-odds of a positive classification (i.e. as permafrost). The second model uses a cutoff. Any locations where the process is positive are classified positively, while those that are negative are classified negatively. A probability of misclassification then gives the likelihood. The third model depends on two separate processes. The first represents a positive classification, while the second a negative classification. Of these two, the process with greater value at a location provides the classification. A probability of misclassification is also used to formulate the likelihood for this model. In all three cases, realizations of the underlying Gaussian processes were generated using a process convolution. A grid of knots (whose values were sampled using Markov Chain Monte Carlo) were convolved using an anisotropic Gaussian kernel. All three models provided adequate classifications, but the single and two-process models showed much tighter bounds on the border between the two states

Phylogeny as a proxy for ecology in seagrass amphipods: which traits are most conserved?

Increasingly, studies of community assembly and ecosystem function combine trait data and phylogenetic relationships to gain novel insight into the ecological and evolutionary constraints on community dynamics. However, the key to interpreting these two types of information is an understanding of the extent to which traits are phylogenetically conserved. In this study, we develop the necessary framework for community phylogenetics approaches in a system of marine crustacean herbivores that play an important role in the ecosystem functioning of seagrass systems worldwide. For 16 species of amphipods and isopods, we (1) reconstructed phylogenetic relationships using COI, 16S, and 18S sequences and Bayesian analyses, (2) measured traits that are potentially important for assembling species between and within habitats, and (3) compared the degree to which each of these traits are evolutionarily conserved. Despite poor phylogenetic resolution for the order Amphipoda as a whole, we resolved almost all of the topology for the species in our system, and used a sampling of ultrametric trees from the posterior distribution to account for remaining uncertainty in topology and branch lengths. We found that traits varied widely in their degree of phylogenetic signal. Body mass, fecundity, and tube building showed very strong phylogenetic signal, and temperature tolerance and feeding traits showed much less. As such, the degree of signal was not predictable based on whether the trait is related to environmental filtering or to resource partitioning. Further, we found that even with strong phylogenetic signal in body size, (which may have large impacts on ecosystem function), the predictive relationship between phylogenetic diversity and ecosystem function is not straightforward. We show that patterns of phylogenetic diversity in communities of seagrass mesograzers could lead to a variety of interpretations and predictions, and that detailed study of trait similarities and differences will be necessary to interpret these patterns

Crustal evolution of the northern Arabian Platform beneath the Syrian Arab Republic

Copyright 1991, John Best. See also: http://atlas.geo.cornell.edu/dissertations/Best_1991.htmNewly released geological and geophysical data from the Syrian Arab Republic are used to document the geological history of the northern Arabian platform in the Middle East. The primary observation of this synthesis is the focusing of various phases of Phanerozoic deformation (Mesozoic rifting and Cenozoic transpression) along strike of a proposed Proterozoic suture that has acted as a long-lived zone of crustal weakness. This deformation zone is presently manifested by the intracontinental Palmyride mountain belt, an inverted rift, trending NE-SW through central Syria. The geological history recognized for the northern Arabian platform is similar in many respects to that of the southern Arabian platform, including: (1) Proterozoic convergence and cratonization, (2) minor Cambrian extension, (3) a relatively stable Paleozoic margin of Gondwanaland marked by predominantly clastic deposition, (4) eastward tilting of the Arabian plate in the Cenozoic. The important difference in the evolution of the northern platform from the southern platform occurs during the Mesozoic with the development of the Levantine margin in the eastern Mediterranean and the Palmyride rift in the continental interior. The intracontinental Palmyride mountain belt is the result of Late Cretaceous-present inversion of the Palmyride rift. Reactivation of rift boundary faults occurred in response to transpressive movement along basement-controlled strike-slip faults. The belt is divided into three provinces based on changes in structural style: the south Palmyride fold belt characterized by narrow, en enchelon ridges, the Bishri, and Bilas blocks expressed as broad, antiformal structures. The mountain belt may be characterized by thin-skinned deformation in the south fold belt and thick-skinned deformation in the northern and eastern provinces

Investigation of length changes in prestressed concrete slabs with outside exposures

In general, pavements may be classed as being either rigid or flexible. The term “rigid pavement”, as commonly used in the United States, is applied only to wearing surfaces constructed of portland-cement concrete. All other types of pavements are classed as “flexible”. A pavement constructed of portland-cement concrete is assumed to possess considerable flexural strength which will permit it to act as a beam and allow it to bridge any minor irregularities which may occur in the base on which it rests, hence the term “rigid”…. In view of the experience and information gathered in over 50 years of road building, one might expect to find precise and standardized methods for the design of portland-cement concrete pavements. Instead, nearly every state has different design practices. Because of increased usage and heavier loadings, what was once considered good design practice is now to some extent inadequate. The results of the increased usage and loadings is evident in the fact that pavements that were designed for a life expectancy of 20 to 25 years are being completely destroyed in approximately half that time…. It is the purpose of this investigation to determine, by tests conducted on normal pavement concretes placed on prepared subgrades, the daily cycles of length changes with temperature variation, and also to determine the longtime changes in length of slabs on subgrades with moisture and evaporation variables approximating those of normal highway slabs. Each slab will be subjected to a known, relatively constant, average intensity of prestress. In accord with the above purpose, the primary objective of this project is to determine overall length changes for daily and seasonal cyclic changes of temperature and moisture on short sections of prestressed concrete slabs. The slabs will be placed in outside exposure on prepared highway subbases. A secondary objective of this project is to investigate changes in one-directional warping measurements along the length of these slabs. This will be done under the different intensities of average known prestress for daily and seasonal changes in slab temperature and moisture --Introduction, pages 1, 2, 5

Effects of ethephon on sex expression and yields of summer squash

The plant growth regulator 2-chloroethylphosphonic acid (ethephon) was applied to four summer squash cultivars to determine its effects on yield and flowering habits. Four ethephon rates, three application regimes, and two locations were used in field studies. Flowering patterns were examined for two cultivars under early fall greenhouse growth conditions. Four ethephon rates and four stages of plant growth for ethephon application were utilized in the greenhouse study. Ethephon levels of 150, 300, and 600 ppm were tested in field studies. The 150 ppm level resulted in the highest yields with the least amount of quality reduction as defined by percentage of fruit marketable. The 600 ppm level resulted in the highest percentage of unmarketable fruit, especially for Zucchini cultivars. Fruit quality was lowered by inadequate pollination, and supplemental pollen sources planted near ethephon treated plants helped alleviate the problem. Average fruit weight was lowered by ethephon for about two weeks after treatment. In field studies, ethephon at the 150 ppm rate applied at the three-leaf stage resulted in higher early yields than did the control in all cultivars. \u27Early Prolific\u27 (a yellow open-pollinated cultivar), \u27Dixie\u27 (a yellow hybrid cultivar), \u27Aristocrat\u27 and \u27Senator\u27 (Zucchini cultivars) exhibited early yield increases of 540, 58, 51, and 150 per cent respectively with the 150 ppm, three-leaf stage ethephon treatment. Only Senator exhibited a season total yield increase (32 percent) resultant from ethephon treatment. Ethephon treatment resulted in an increase in total fruit number but not total yield for Early Prolific. Split application of 150 or 300 ppm ethephon were no more successful in increasing yields than were single, three-leaf stage applications of these treatments. Plants treated with split applications tended to distribute yields throughout the season rather than concentrating them at the early part of the harvest period, thereby exhibiting a yield pattern similar to that of control plants. Ethephon levels of 75, 150, and 300 ppm resulted in about the same total numbers of pistillate flowers as did the control for either Early Prolific or Dixie plants grown under early fall greenhouse conditions. However, due to a shortage of staminate flowers, all ethephon treated plants had significantly fewer pollinated pistillate flowers than did control plants. Numbers of pistillate primordia which formed on plants but aborted prior to reaching the flowering stage were 307 to 382 percent higher for Early Prolific plants treated with 75 and 300 ppm ethephon respectively than for control plants. Plants treated with ethephon at the first flower stage had more fruit formed partheno-carpically than did control plants or those treated at the seed stage (seeds were soaked in ethephon for 30 minutes prior to planting) or first fruit stage

Sequential cropping of vegetables for market windows

With the decline in profitability of several Southern commodities, farmers in Tennessee and other surrounding areas have been forced to reevaluate the crops they are producing. This study provides information that is beneficial to these farmers on alternative crops they can use in their decision making processes. How good an alternative crop is at producing income on average can be determined by using simple statistical procedures and price data for different crops. Price risk, which is one of the most important risks to be considered when growing vegetables, can be observed by finding the standard deviation that goes with the average price. A coefficient of variation can be found using the average price and the standard deviation for a product. The coefficient of variation provides a relative risk rating for comparison of the vegetables in this study. Production risk can also be looked at using temperature data in the same manner as price data. Data needed for the study came from several different sources. The price data for the vegetables came from wholesale market reports at different locations in the region. The temperature data used came from the state of Tennessee. Other budgets and expenses came from different publications and businesses around the area. Vegetable production in Tennessee appears to be profitable under the conditions of this study. Depending on the actual size of his farm and his current financial condition, a farmer can produce for market windows by targeting his harvest dates and increase his income. Other farmers with fewer resources who prefer lower risk can sequence crops and make the most effective use of their land and other limiting resources

Costs and Benefits of Full Dual-Frame Telephone Survey Designs

Assesses the cost, sample composition, weighting, and substantive effect on survey results involved in interviewing respondents by cell phone, including those with landlines. Includes demographic profiles of cell phone-only, landline-only, and dual users