Horticultural Studies 1999

Horticultural Studies 1999 is the second edition of a Research Series dedicated to horticultural programs in the University of Arkansas Division of Agriculture and the Dale Bumpers College of Agricultural, Food and Life Sciences. This publication summarizes research, extension, and educational activities that serve horticultural industries and interest groups in Arkansas. The goals of this publication are to provide relevant information to the growers and end-users of horticulture crops in Arkansas and to inform the citizens of Arkansas and the surrounding region of activities related to horticulture

Horticultural Studies 1998

Horticulture connects with people in many ways including an enhanced awareness concerning the importance of fruits and vegetables in our diet. The health benefits of such a diet is gaining wide recognition throughout the public and will likely provide tremendous opportunities for research, education and business development. Significant faculty additions and programmatic efforts were made to the university’s fruit and vegetable programs in 1998

Contractually altering integrated project delivery\u27s success

Invigorated Project Delivery (IPD) is one of the newest delivery methods within the construction industry. This new approach revolutionizes the way projects are conducted by creating a collaborative work environment that harnesses the resources of its participants to create a finished product that is both of a higher quality and cheaper. This is made possible through the delivery method\u27s unique focus which prides itself on its reputation for increasing efficiency levels and reducing project waste. Even though IPD is wonderful delivery method that looks great on paper, it does not change the fact that the delivery method is currently struggling to produce successful projects. Many professionals ignore the issues surrounding failed projects and merely push IPD off as a failed process. These individuals believe it is the delivery methods fault by claiming the process is flawed. However, such individuals are neglecting to consider alternative issues surrounding their failed projects. After all, the delivery method is not the only piece of the project delivery puzzle. The IPD contract provides detail on how a project will be delivered. Essentially everything there is to know will be located within a project\u27s contract. My theory is IPD contracts are limiting the success of this delivery method. This research thesis will set out to accomplish two goals: First, determine if IPD contracts are limiting the delivery methods success. Upon determining the merit of this claim, the research will then tum to the areas of the contracts that may be responsible for limiting IPD\u27s success. IPD is currently believed to be a failed method. I hope this thesis shows otherwise

Modelling individual variability in cognitive development

Investigating variability in reasoning tasks can provide insights into key issues in the study of cognitive development. These include the mechanisms that underlie developmental transitions, and the distinction between individual differences and developmental disorders. We explored the mechanistic basis of variability in two connectionist models of cognitive development, a model of the Piagetian balance scale task (McClelland, 1989) and a model of the Piagetian conservation task (Shultz, 1998). For the balance scale task, we began with a simple feed-forward connectionist model and training patterns based on McClelland (1989). We investigated computational parameters, problem encodings, and training environments that contributed to variability in development, both across groups and within individuals. We report on the parameters that affect the complexity of reasoning and the nature of ‘rule’ transitions exhibited by networks learning to reason about balance scale problems. For the conservation task, we took the task structure and problem encoding of Shultz (1998) as our base model. We examined the computational parameters, problem encodings, and training environments that contributed to variability in development, in particular examining the parameters that affected the emergence of abstraction. We relate the findings to existing cognitive theories on the causes of individual differences in development

Measuring Stolons and Rhizomes of Turfgrasses Using a Digital Image Analysis System

Length and diameter of stolons or rhizomes are usually measured using simple rulers and calipers. This procedure is slow and laborious, so it is often used on a limited number of stolons or rhizomes. For this reason, these traits are limited in their use for morphological characterization of plants. The use of digital image analysis software technology may overcome measurement errors due to human mistakes, which tend to increase as the number and size of samples also increase. The protocol can be used for any kind of crop but is particularly suitable for forage or grasses, where plants are small and numerous. Turf samples consist of aboveground biomass and an upper soil layer to the depth of maximum rhizome development, depending on the species of interest. In studies, samples are washed from the soil, and stolons/rhizomes are cleaned by hand before analysis by digital image analysis software. The samples are further dried in a laboratory heating oven to measure dry weight; therefore, for each sample, the resultant data are total length, total dry weight, and average diameter. Scanned images can be corrected before analysis by excluding visible extraneous parts, such as remaining roots or leaves not removed with the cleaning process. Indeed, these fragments normally have much smaller diameters than stolons or rhizomes, so they can be easily excluded from analysis by fixing the minimum diameter below which objects are not considered. Stolon or rhizome density per unit area can then be calculated based on sample size. The advantage of this method is quick and efficient measurement of the length and average diameter of large sample numbers of stolons or rhizomes

Modelling the complex dynamics of vegetation livestock and rainfall in a semiarid rangeland in South Africa

Predicting the effect of different management strategies on range condition is a challenge for farmers in highly variable environments. A model that explains how the relations between rainfall, livestock and vegetation composition vary over time and interact is needed. Rangeland ecosystems have a hierarchical structure that can be described in terms of vegetation composition, stocking rate and rainfall at the ecosystem level, and the performance of individual animals and plants at the lower level. In this paper, we present mathematical models that incorporate ideas from complex systems theory to integrate several strands of rangeland theory in a hierarchical framework. Compared with observed data from South Africa, the model successfully predicted the relationship between rainfall, vegetation composition and animal numbers over 30 years. Extending model runs over 100 years suggested that initial starting conditions can have a major effect on rangeland dynamics (divergence), and that hysteresis is more likely during a series of low rainfall years. Our model suggests that applying an upper threshold to animal numbers may help to conserve the biodiversity and resilience of grazing systems, whilst maintaining farmers’ ability to respond to changing environmental conditions, a management option here termed controlled disequilibrium

The classification and structure of megafaunal assemblages in the Venezuela Basin, Caribbean Sea

Data from 23 benthic trawls collected from the Venezuela Basin (3411–5062 m water depth) indicate that megafauna are less abundant than in basins of similar depths in the Atlantic and are segregated by sedimentary province. Taxonomic assemblages, in terms of abundance and biomass, from three sites coincide with distinctions of sedimentary characteristics among the pelagic, hemipelagic and turbidite sedimentary provinces. Mollusks, decapods and fishes are most abundant in trawls collected from the pelagic and hemipelagic provinces and anemones and holothurians are most abundant in trawls collected from the turbidite province. Sponges dominate the biomass of fauna in trawls collected in the turbidite and hemipelagic provinces and fishes dominate the biomass of trawls collected in the pelagic province. Several biological and physical aspects of the basin contribute to the segregation of the megafauna into distinct communities. Sponges and anthropogenic debris (coal, coal clinker and tar balls) reaching the sea floor create a habitat that is exploited by sessile suspension feeders requiring a hard substrate. Filter-feeding anemones attached to debris occur in such abundance that it elevates the importance of suspension feeders and depresses species diversity at the turbidite site. Biomass and average size of megafaunal deposit feeders in the basin decrease with decreasing amounts of organic carbon and nitrogen content of the sediment. Distribution and composition of filter-feeding megafaunal biomass in the Venezuela Basin are explained largely by proximity to sources of organic matter. Detrital carbonate may also play a role in controlling distribution and density of megafauna by diluting food resources in the sediments

Beliefs as Self-Sustaining Networks: Drawing Parallels Between Networks of Ecosystems and Adults’ Predictions

In this paper, we argue that beliefs share common properties with the self-sustaining networks of complex systems. Matching experiences are said to couple with each other into a mutually reinforcing network. The goal of the current paper is to spell out and develop these ideas, using our understanding of ecosystems as a guide. In Part 1 of the paper, we provide theoretical considerations relevant to this new conceptualization of beliefs, including the theoretical overlap between energy and meaning. In Part 2, we discuss the implications of this new conceptualization on our understanding of belief emergence and belief change. Finally, in Part 3, we provide an analytical mapping between beliefs and the self-sustaining networks of ecosystems, namely by applying to behavioral data a measure developed for ecosystem networks. Specifically, average accuracies were subjected to analyses of uncertainty (H) and average mutual information (AMI). The ratio between these two values yields degree of order, a measure of how organized the self-sustained network is. Degree of order was tracked over time and compared to the amount of explained variance returned by a categorical nonlinear principal components analysis (CATPCA). Finding high correspondence between the two measures of order, together with the theoretical groundwork discussed in Parts 1 and 2, lends preliminary validity to our theory that beliefs have important similarities to the structural characteristics of self-sustaining networks