Species interactions restrict or promote population growth, structure communities, and contribute to evolution of diverse taxa. I seek to understand how multiple species interactions are maintained, how human altered species interactions influence evolution, and explore factors that contribute to variation in species interactions. In Chapter 1, I examine how plants interact with multiple guilds of mutualists, many of which are costly interactions. The evolution of traits used to attract different mutualist guilds may be constrained due to ecological or genetic mechanisms. I asked if two sets of plant traits that mediate interactions with two guilds of mutualists, pollinators and ant bodyguards, were positively or negatively correlated across 36 species of Gossypium (cotton). Traits to attract pollinators were positively correlated with traits to attract ant bodyguards. Rather than interaction with one mutualist guild limiting interactions with another mutualist guild, traits have evolved to increase attraction of multiple mutualist guilds simultaneously. In Chapters 2 and 3, motivated by the fact that agriculture covers nearly 50% of the global vegetated land surface, I explore the consequences of changes in plant mutualist and antagonist guilds in agriculture for selection on plant traits. I first explore how agriculture alters abundance and community structure of mutualist pollinators and antagonist seed predators of wild Helianthus annuus texanus. Mutualists were more abundant near crops, whereas antagonists were more abundant far from crops near natural habitat. In addition, mutualist pollinator communities were more diverse near sunflower crops. Plant mutualists and antagonists respond differently to agriculture. Next, I explore how these changes in abundance and community structure of mutualists and antagonists influenced natural selection on H. a. texanus floral traits. Natural selection on heritable floral traits differed near versus far from crop sunflowers, and overall selection was more heterogeneous near crop sunflowers. Furthermore, mutualist pollinators and antagonist seed predators mediated these differences in selection. Finally, in Chapter 4, I ask if variation in interaction outcomes differs across types of species interactions. Furthermore, I examined the relative importance of factors that create context-dependency in species interactions. Using meta-analysis of 353 papers, we found that mutualisms were more likely to change sign of the interaction outcome when compared across contexts than competition, and predation was the least likely to change sign. Overall, species identity caused the greatest variation in interaction outcomes: whom you interact with is more important for context-dependency than where or when the interaction occurs. Additionally, the most important factors driving context-dependency differed significantly among species interaction types. Altogether, my work makes progress in understanding how species maintain interactions with multiple guilds of mutualists, how agriculture alters species interactions and subsequent natural selection, and the variation in species interaction outcomes and their causes.

In this work, Kurt Holukoff examines three formal approaches to representing valid inferences in reasoning regarding obligation and its cognates: deontic logic. He argues that an appropriate formalization of deontic logic should take genuine moral dilemmas seriously, be capable of representing trumping-like reasoning, and not make the naturalistic fallacy valid as a matter of logic. The three systems he investigates are, the Standard Deontic logic, a Relevant Deontic logic, and Schotch and Jennings’ multiple moral accessibility relations Deontic logic. The Standard Deontic logic has seemingly insurmountable problems representing both fruitful reasoning from an inconsistent set of obligations and trumping-like reasoning. Moreover, the naturalistic fallacy is valid in the Standard Deontic logic. The Relevant deontic logic that the author examines is capable of representing fruitful reasoning from an inconsistent set of obligations and does not make valid the naturalistic fallacy. However, the author argues that the Relevant deontic logic needs some revisions in order to represent trumping-like reasoning. Likewise, the author finds that Schotch and Jennings’ Deontic logic is capable of representing fruitful reasoning from an inconsistent set of obligations. However, in order to represent trumping-like reasoning, revisions to Schotch and Jennings’ Deontic logic are apparently required. Similar revisions are seemingly required to block the naturalistic fallacy, which is otherwise valid in Schotch and Jennings’ original system.

In this work, Kurt Holukoff examines three formal approaches to representing valid inferences in reasoning regarding obligation and its cognates: deontic logic. He argues that an appropriate formalization of deontic logic should take genuine moral dilemmas seriously, be capable of representing trumping-like reasoning, and not make the naturalistic fallacy valid as a matter of logic. The three systems he investigates are, the Standard Deontic logic, a Relevant Deontic logic, and Schotch and Jennings’ multiple moral accessibility relations Deontic logic. The Standard Deontic logic has seemingly insurmountable problems representing both fruitful reasoning from an inconsistent set of obligations and trumping-like reasoning. Moreover, the naturalistic fallacy is valid in the Standard Deontic logic. The Relevant deontic logic that the author examines is capable of representing fruitful reasoning from an inconsistent set of obligations and does not make valid the naturalistic fallacy. However, the author argues that the Relevant deontic logic needs some revisions in order to represent trumping-like reasoning. Likewise, the author finds that Schotch and Jennings’ Deontic logic is capable of representing fruitful reasoning from an inconsistent set of obligations. However, in order to represent trumping-like reasoning, revisions to Schotch and Jennings’ Deontic logic are apparently required. Similar revisions are seemingly required to block the naturalistic fallacy, which is otherwise valid in Schotch and Jennings’ original system.

IDS (Intrusion Detection System) detect intrusions and generate alerts to administrator. With Internet more and more popular, IDS products a lot of alerts make administrators spend much time to analyze to understand the network situation. Many online services record services details on the log, as the same administrators spend much time to analyze logs. IDS suffer from several limitations : amount of alerts, most of the alerts are false positive, certain attacks may not be detected by IDS. To solve limitations of IDS, four alert correlation techniques : alert attributions similarity, predefined attack scenarios, multi-stage approaches, verification to filter positive alerts. Network attack consist of multiple steps, each step may leave evidences on log or detected by IDS. Service logs record normal and abnormal detail behaviors, IDS alerts record single attack step. Alerts and logs first merge into meta-alert and meta-log. Second, we use two features to filter meta-log. Then, correlate meta-alert and filtered meta-log to produce report to administrators.

Information collection and discovery tasks involve aggregation and manipulation of information resources. An information resource is a location from which a human gathers data to contribute to his/her understanding of something significant. Repositories of information resources include the Google search engine, the ACM Digital Library, Wikipedia, Flickr, and IMDB. Information discovery tasks involve having new ideas in contexts of information collecting. The information one needs to collect is large and diverse and hard to keep track of. The heterogeneity and scale also make difficult writing software to support information collection and discovery tasks. Metadata is a structured means for describing information resources. It forms the basis of digital libraries and search engines. As metadata is often called, "data about data," we define meta-metadata as a formal means for describing metadata as an XML based language. We consider the lifecycle of metadata in information collection and discovery tasks and develop a metametadata architecture which deals with the data structures for representation of metadata inside programs, extraction from information resources, rules for presentation to users, and logic that defines how an application needs to operate on metadata. Semantic actions for an information resource collection are steps taken to generate representative objects, including formation of iconographic image and text surrogates, associated with metadata. The meta-metadata language serves as a layer of abstraction between information resources, power users, and application developers. A power user can enhance an existing collection visualization application by authoring meta-metadata for a new information resource without modifying the application source code. The architecture provides a set of interfaces for semantic actions which different information discovery and visualization applications can implement according to their own custom requirements. Application developers can modify the implementation of these semantic actions to change the behavior of their application, regardless of the information resource. We have used our architecture in combinFormation, an information discovery and collection visualization application and validated it through a user study.

Many fields of economics point to technology as the primary vehicle for change. Agencies pushing change often promote technology adoption to achieve their goals. To improve our understanding of how efforts to push new technologies should be focused, two studies are undertaken. The first study defines and tests for universality using meta-regression analysis on 170 analyses of agricultural production technologies. The second study, a case study on an emerging information technology - climate forecasts, examines how the timing of adoption affects the benefits. A factor exhibiting a systematic positive or negative effect on technology adoption is a universal factor. If the impact is the same regardless of location or technology type, the factor is strongly universal. The factor is weakly universal if the impact varies by location or technology type. Education and farm size are found to be weakly positive universal, age is found to be weakly negative universal, and outreach is not found to be a universal factor in the adoption of technology. These results indicate that technology-promoters may want to change their approach and focus on younger, more educated producers with larger farms. In the second study, an international wheat trade model incorporating climate variability is used to simulate different scenarios when wheat producers in the U.S., Canada, and Australia adopt ENSO-based forecasts for use in production decisions. Adoption timing and levels are varied across countries in the different scenarios. The results are highly consistent. Early adopters benefit the most, there is no incentive for more producers to adopt after 60% to 95% have adopted (meaning the adoption ceiling has been reached), and slower adoption corresponds to ceilings closer to 60% than 95%. Examining technology adoption from two angles provides a deeper understanding of the adoption process and aids technology-promoters in achieving their goals. In addition to focusing on younger, more educated producers with larger farms, technology-promoters wanting wide-spread adoption with high benefits need to push constituents to adopt early and fast.

The purpose of this study was to quantitatively evaluate the overall effectiveness of eating disorder prevention programs and to investigate potential moderating variables that may influence the magnitude of intervention effects. Meta-analysis was used to conduct a comprehensive and systematic analysis of data across 46 studies. Effect size estimates were grouped into outcome sets based on the following variables: knowledge, general eating pathology, dieting, thin-ideal internalization, body dissatisfaction, negative affect, and self-esteem. Q statistics were used to analyze the distribution of effect size estimates within each outcome set and to explore the systematic influence of moderating variables. Results revealed large effects on the acquisition of knowledge and small net effects on reducing maladaptive eating attitudes and behaviors at posttest and follow-up. These programs were not found to produce significant effects on negative affect, and there were inconsistent effects on self-esteem across studies. Population targeted was the sole moderator that could account for variability in effect size distributions. There was a tendency toward greater benefits for studies targeting participants considered to be at a relatively higher risk for developing an eating disorder. Previous assumptions regarding the insufficiency of "one-shot" interventions and concerns about the iatrogenic effects of including information about eating disorders in an intervention were not supported by the data. These findings challenge negative conclusions drawn in previous review articles regarding the inability of eating disorder prevention programs to demonstrate behavioral improvements. Although these findings have implications for the prevention of eating disorders, it was argued that a clear link between intervention efficacy and a decreased incidence of eating disorders was not demonstrated. Rather, only direct information was offered about the ability to influence eating disorder related knowledge, attitudes, and behaviors. Specific recommendations related to intervention content, reasonable goals/expectations, and outcome criteria were offered for improving research in this area.

The meta-ecosystem concept is an attempt to combine metacommunity, ecosystem and landscape ecology. In meta-ecosystems, both organismal dispersal and material movement between patches can have important effects on communities. This concept provides a more realistic framework of natural systems by considering both processes jointly. My dissertation presents a case-study of natural metaecosystems by studying the role of waterfowl in structuring zooplankton communities in prairie pothole wetlands in South Dakota. I use observations of natural wetlands, microcosm and mesocosm experiments to show how dispersal of materials and organisms by waterfowl can affect zooplankton abundance and community composition. Waterfowl are conspicuous, behaviorally adaptable, highly mobile and economically important members of wetland habitats. They are thought to have possible effects on zooplankton communities either by dispersing zooplankton propagules among wetlands or by moving nutrients into (via defecation) or out of (via consumption of macrophytes and invertebrates) wetlands. In this dissertation, I show evidence that waterfowl disperse a limited subset of locally rare zooplankton species between wetlands. I also provide experimental evidence that these dispersed species may have impacts on zooplankton community assembly. I also show how input of waterfowl excreta may sometimes have strong impacts on the local community. Very large inputs of goose excreta promote abundance and diversity of zooplankton. However, inputs at more modest levels, such as those routinely found in nature, are rarely detectible. Additions of excreta at levels five-times that typically found in nature produce a possible shift in zooplankton community structure away from both no-excreta communities and communities fertilized with comparable amounts of nitrogen and phosphorus. I postulate that most excreta quickly sinks to the benthos and only a small fraction becomes available for use by zooplankton. On the time scales used in my dissertation, it is only with very large additions of excreta that shifts in the zooplankton community become apparent. My dissertation is one of the first to apply the meta-ecosystem concept to a natural system. It also shows that waterfowl impacts on the zooplankton community may be most important in small wetlands or early in community assembly. / text

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

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