Counting monomials

This paper presents two enumeration techniques based on Hilbert functions. The paper illustrates these techniques by solving two chessboard problems

Human operator response to error-likely situations in complex engineering systems

The causes of human error in complex systems are examined. First, a conceptual framework is provided in which two broad categories of error are discussed: errors of action, or slips, and errors of intention, or mistakes. Conditions in which slips and mistakes might be expected to occur are identified, based on existing theories of human error. Regarding the role of workload, it is hypothesized that workload may act as a catalyst for error. Two experiments are presented in which humans' response to error-likely situations were examined. Subjects controlled PLANT under a variety of conditions and periodically provided subjective ratings of mental effort. A complex pattern of results was obtained, which was not consistent with predictions. Generally, the results of this research indicate that: (1) humans respond to conditions in which errors might be expected by attempting to reduce the possibility of error, and (2) adaptation to conditions is a potent influence on human behavior in discretionary situations. Subjects' explanations for changes in effort ratings are also explored

Assessing the impact of modeling limits on intelligent systems

The knowledge bases underlying intelligent systems are validated. A general conceptual framework is provided for considering the roles in intelligent systems of models of physical, behavioral, and operational phenomena. A methodology is described for identifying limits in particular intelligent systems, and the use of the methodology is illustrated via an experimental evaluation of the pilot-vehicle interface within the Pilot's Associate. The requirements and functionality are outlined for a computer based knowledge engineering environment which would embody the approach advocated and illustrated in earlier discussions. Issues considered include the specific benefits of this functionality, the potential breadth of applicability, and technical feasibility

Postbuckling behavior of graphite-epoxy panels

Structurally efficient fuselage panels are often designed to allow buckling to occur at applied loads below ultimate. Interest in applying graphite-epoxy materials to fuselage primary structure led to several studies of the post-buckling behavior of graphite-epoxy structural components. Studies of the postbuckling behavior of flat and curved, unstiffened and stiffened graphite-epoxy panels loaded in compression and shear were summarized. The response and failure characteristics of specimens studied experimentally were described, and analytical and experimental results were compared. The specimens tested in the studies described were fabricated from commercially available 0.005-inch-thick unidirectional graphite-fiber tapes preimpregnated with 350 F cure thermosetting epoxy resins

Auxin regulates SCFTIR1-dependent degradation of AUX/IAA proteins

The plant hormone auxin is central in many aspects of plant development. Previous studies have implicated the ubiquitin-ligase SCFTIR1 and the AUX/IAA proteins in auxin response. Dominant mutations in several AUX/IAA genes confer pleiotropic auxin-related phenotypes, whereas recessive mutations affecting the function of SCFTIR1 decrease auxin response. Here we show that SCFTIR1 is required for AUX/IAA degradation. We demonstrate that SCFTIR1 interacts with AXR2/IAA7 and AXR3/IAA17, and that domain II of these proteins is necessary and sufficient for this interaction. Further, auxin stimulates binding of SCFTIR1 to the AUX/IAA proteins, and their degradation. Because domain II is conserved in nearly all AUX/IAA proteins in Arabidopsis, we propose that auxin promotes the degradation of this large family of transcriptional regulators, leading to diverse downstream effects

pax1-1 partially suppresses gain-of-function mutations in Arabidopsis AXR3/IAA17

Background: The plant hormone auxin exerts many of its effects on growth and development by controlling transcription of downstream genes. The Arabidopsis gene AXR3/IAA17 encodes a member of the Aux/IAA family of auxin responsive transcriptional repressors. Semi-dominant mutations in AXR3 result in an increased amplitude of auxin responses due to hyperstabilisation of the encoded protein. The aim of this study was to identify novel genes involved in auxin signal transduction by screening for second site mutations that modify the axr3-1 gain-of-function phenotype. Results: We present the isolation of the partial suppressor of axr3-1 (pax1-1) mutant, which partially suppresses almost every aspect of the axr3-1 phenotype, and that of the weaker axr3-3 allele. axr3-1 protein turnover does not appear to be altered by pax1-1. However, expression of an AXR3:: GUS reporter is reduced in a pax1-1 background, suggesting that PAX1 positively regulates AXR3 transcription. The pax1-1 mutation also affects the phenotypes conferred by stabilising mutations in other Aux/IAA proteins; however, the interactions are more complex than with axr3-1. Conclusion: We propose that PAX1 influences auxin response via its effects on AXR3 expression and that it regulates other Aux/IAAs secondarily

A Narrative Case Study Describing the Support Culture for the Change Process in a Small Parochial, Boarding Secondary School

Problem. History acknowledges that change in education is difficult. Literature suggests that the educational system plays a critical role in individual school-change initiatives. Educators need to seek for better understanding of the influence that system issues have on the change process. This study describes a change process experienced by one small boarding school in a parochial school system. It describes the change process as experienced by teachers in the school, administrators at various systemic levels, and parents of students in the school. Their story brings greater understanding of how culture of the system impacts school change. Method. This research used a qualitative single-case design in order to gain insight from the experience of the educators connected to the school in order to achieve greater understanding of how a system reacts to a school making significant change. The case was a small boarding high school in the Northeastern United States. The school is a part of the Seventh-day Adventist system of education, which is the largest Protestant system in the world. Data were collected by interviews, focus groups, observation, and from documents. The data were analyzed for themes, connectedness, and constructions that did or did not intertwine, affirm, or conflict with each other. The stories were then retold in a chronological pattern describing the school‘s experiences from as many perspectives as possible. Results. The participants in this study described a system conflicted in its quest to maintain and improve on the quality of Adventist education. Five characteristics were revealed in the system as it related to the process of change. 1. The system tended to operate primarily from a well-established paradigm of holding schools accountable. 2. The system did not demonstrate a thorough understanding of what is known about change. 3. The system revealed that it lacked effective communication mechanisms and processes. 4. The system demonstrated some understanding of its role in school change, but events revealed it still had much to learn. 5. The system revealed a growing desire to facilitate positive educational change. Discussion. Education leadership within the system seemed to realize a need for change in order to bring improvement, yet frustrations remained from many who observed continued pressure for the school to operate within traditional approaches to education, only to do it better and more diligently. As the change was measured against established expectations, concerns were increased. When the change brought a level of chaos and a level of dissatisfaction among students and parents, the system responded by imposing greater accountability. The school‘s response to the expressed concerns from various stakeholders was to scale back the change. There is a need for the development of processes to facilitate change where there is demonstrated understanding and support of change experiences that are usually chaotic. This education system like many others found its structure to be a hindrance to effective communication. There was a recognition that different support mechanisms were needed to develop better practices in education–beyond just verbal directives that proclaim support of change. This recognition came primarily from the administration level immediately responsible for the school. At this level in the system there was a measure of collaboration created in the change process. However, overall, the system did not provide deliberate, ongoing collaboration to develop new frames of references for all educators in the system. The result was an organization that had not created a context supportive of change. There were times that leaders from various levels of the system stepped in to provide a collaborative solution to problems. When that happened the change process was energized. Leadership also acknowledged weaknesses in the system‘s support process for change, yet no dramatic changes were visible as the study ended. The process provided information demonstrating that education leadership within the system could know how to better facilitate change and, it was clear, they desired to learn the lessons provided

Latino representation in U.S. legislatures: interests, behavior, and influence

Despite the growth of Latinos in the general population and in legislatures, their impact on the political process has received little scholarly attention. In this project, I present a theoretical framework of Latino legislative behavior that draws upon two important concepts of representation- descriptive and substantive- to better understand how ethnicity influences legislative activity and whether it is dependent on such factors as institutional context, legislative composition, and constituency characteristics. The project is unique in its comprehensive analysis of the legislative process and in its mixed methodological approach which includes both quantitative and qualitative elements. The analysis involves five parts: agenda setting, committee participation, roll call voting, legislator interviews, and a discussion about defining Latino interests. Previous literature has examined the effects of ethnicity at some stages of representation, but it is difficult to place the strength and significance of those findings in relative terms. During agenda setting, I find that Latinos are more likely than non-Latinos to sponsor legislation narrowly defined as “Latino interests,” especially when Latinos make up a small percentage of their party within a chamber. In committee deliberations, the role of ethnicity is more inconsistent; the ethnicity of a legislator and/or the Latino saliency of a bill significantly affect committee participation in specific legislative chambers. During roll call voting, ethnicity has no discernable impact. In fact, party appears to be the only consistent determinant of roll call activity. The analysis of legislator interviews (both Latino and non-Latino) provides valuable insight into the attitudes, motivations, and intentions of those actually providing representation, and not only serves to support some of the quantitative results, but adds to the overall quality of the research on representation. Finally, a discussion about defining a Latino political agenda reveals that research on Latino issues often relies on legislative initiatives to identify “Latino interests” and that these interests are most visible when they are narrowly defined. This comprehensive project indicates that the role of ethnicity in the legislative process is variable depending on institutional context, extent of political cohesiveness among Latino legislators, and the mechanisms and goals for a particular legislative activity

Financial Aid Packages and College Enrollment Decisions: An Econometric Case Study

We study the effects of a change in financial aid policy introduced by a Northeastern university in 1998. Prior to that time, the university's financial aid packages for low-income students consisted of grants, loans, and campus jobs. After the change, the entire loan portion of the package for low-income students was replaced with grants. We find the program increased the likelihood of matriculation by low-income students by about 3 percentage points, although the effect is not statistically significant. The effect among low-income minority students was between 8 and 10 percentage points and statistically significant at the 10 percent level.