What Fire Chiefs Think and Organizational Directors Know: A Study of the Potential Benefits of Higher Education for the Fire Service

Dilks, John Daniel, Jr ProQuest Dissertations & Theses The Florida State 2018 해외박사(DDOD)

The fire chiefs of today realize the importance of higher education. This is evident in the seminal works of the 1966 Wing Spread I conference and the United States Fire Administration's Fire and Emergency Services Higher Education Project (FESH. The mixed methods approach demonstrated that the quantitative study results were more than adequate to provide a snap shot of Florida's Fire Service in regards to their perception of necessity for higher education in the development of future of.

A study of the impact of the New Jersey core curriculum content standards on the instructional practices of teachers in grades 1--4

Dilks, David H Seton Hall University, College of Education and Hu 2002 해외박사(DDOD)

With the implementation of the Goals 200 Act in May 1996, the state of New Jersey began to work, in earnest, to develop its own state-wide standards describing what all students should know and be able to do upon completion of a thirteen-year public education. The purpose of this research study was to examine the perceptions of grades 1–4 teachers, elementary principals, and district-level administration regarding the effects of those standards on instructional practices in the state. Questionnaires were used to solicit quantitative data in the areas of: (a) Appropriateness of Standards and Tests, (b) Allocation of Instructional Time, and (c) Instructional Practice. Personal interviews were conducted to secure qualitative data in those same categories. Analysis of the data revealed that, while teachers and administrators alike perceive the standards as appropriate, they feel the level of difficulty of the standards is increasingly less defined as the grade level is further removed from the grade 4 benchmark and they are not attainable by all students. A considerable majority of all respondents (nearly three-fourths) indicated a lack of confidence in the Elementary School Proficiency Assessment (ESPA) as an instrument for gauging achievement of the standards. Both the quantitative and qualitative data showed that reallocation of instructional time has taken place and that it has been done along the lines of testing dictates. With regard to instructional practices, it appears that, while change has occurred in what is taught, little significant change has taken place in how it is taught. Insufficient staff development is identified throughout this research as a shortfall in the implementation of the standards. As it also appears rather consistently in the review of literature, it would seem to be a foundation issue which the state and local districts might wish to address.

Examination of the twin-arginine translocation pathway in bacteria and archaea

Dilks, Kieran James University of Pennsylvania 2006 해외박사(DDOD)

The twin-arginine translocation (Tat) pathway is a relatively recently discovered protein translocation mechanism that is capable of facilitating the movement of prefolded proteins across cellular membranes. The overall physiological role of this pathway, as well as the mechanism of protein secretion via the Tat pathway, has been best described in Escherichia coli. However, the role and mechanism of the Tat pathway have not been described for other organisms in any great detail. This study involves the computational characterization of the twin-arginine translocation pathway in different bacteria and archaea in an effort to determine how various organisms are using the Tat pathway. Such analyses predicted that while many prokaryotes lacked the Tat pathway or used this secretory mechanism to translocate only a few substrates, other organisms targeted a significant fraction of the secretome to the Tat pathway for translocation. In addition, the wide variety of functional proteins predicted as Tat substrates indicated that in many prokaryotes the Tat pathway is a general translocation machinery (unlike what was assumed based on E. coli analyses). Two organisms with an extraordinary high number of Tat substrates, Haloferax volcanii and Streptomyces coelicolor, were further analyzed using genetic and biochemical tools. In H. volcanii , seven distinct proteins (including potential C-terminal anchored proteins and lipoproteins) were confirmed as Tat substrates. The presence of three of tat machinery genes was required for viability in H. volcanii when grown under aerobic conditions in complex media (representing the first report of requirement for this pathway under such growth conditions). The translational products of these genes also exhibited unique biochemical localization and primary structure that may represent an adaptation to the unique utilization of the Tat pathway in this organism. In our analyses of the S. coelicolor Tat pathway, it was found that many predicted Tat substrates were in fact secreted in a Tat-dependent manner, however the tat machinery genes were not essential for viability in this gram-positive bacterium.

Involutions on Baxter Objects, and q-Gamma Nonnegativity

Dilks, Kevin University of Minnesota 2015 해외박사(DDOD)

Baxter numbers are known to count several families of combinatorial objects, all of which come equipped with a natural involution. In this paper, we add a combinatorial family to the list, and show that the known bijections between these objects respect these involutions. (Abstract shortened by ProQuest.).

Human adult cortical reorganization and consequent visual distortion

Dilks, Daniel D The Johns Hopkins University 2006 해외박사(DDOD)

In the visual system, cortical reorganization has principally been demonstrated in studies of adult animals: If a region of primary visual cortex (VI) loses its usual input (e.g., due to retinal damage), neurons in that region begin responding to stimuli that normally activate adjacent V1 cortex. This dissertation asks whether cortical reorganization occurs in the human adult visual system, and if so, what the perceptual consequences might be. These questions are addressed by studying an adult stroke patient, BL. BL has damage to the right-hemisphere inferior optic radiations. This damage caused a loss of sensory input to the V1 region representing the upper left visual field (LVF), producing a left superior homonymous quadrantanopia (i.e., a scotoma or blind area in the upper left quadrant). However, primary visual cortex itself is intact. Interestingly, BL exhibits dramatic distortion of perceived shape for stimuli presented in the lower LVF: The stimuli appear vertically elongated (toward and into the blind upper quadrant). For example, when shown a circle, BL reports seeing a "cigar" extending upward; when shown a square, he reports seeing a vertically-elongated "rectangle"; and when shown an upside down triangle, he reports seeing a "pencil" standing upright. Psychophysical testing confirmed the perceptual distortion, and established that the vertical but not the horizontal dimension was affected. I hypothesized that the perceptual distortion in the lower LVF was a consequence of V1 reorganization. BL's stroke did not damage V1 directly, but the V1 region representing most of the upper LVF was deprived of its usual input (due to optic radiation damage). Neurons in the deafferented region may consequently have become responsive to inputs from the lower LVF, such that stimuli presented in the lower LVF activated not only the V1 region representing this area, but also the adjacent region that previously received input from the upper LVF. If activation of this latter region were still treated by BL's visual system as representing upper LVF stimulation, stimuli in the lower LVF might well appear vertically elongated. Additional psychophysical experiments confirmed several predictions following from my hypothesis. Results revealed that the deficit is selective to vision (i.e., tactile shape judgments are intact); that vertical distance as well as shape judgments are affected; that the vertical distortion arises in a retinocentric frame of reference; that the deficit affects not only vision-for-perception, but also vision-for-action (grip aperture); and that the extent of vertical distortion monotonically decreases with distance from the blind quadrant. Additionally, I used functional magnetic resonance imaging (fMRI) to seek evidence for cortical reorganization in BL (i.e., whether there are any changes in the visual cortical topographical map). Results revealed that there is activation in the deprived cortical area when a visual stimulus is presented below this area. Visual cortex deprived of input from the upper LVF has apparently become responsive to stimuli in the lower LVF. Taken together, these studies show that BL's perceptual distortion results from V1 reorganization, providing the first clear demonstration of cortical reorganization in the adult human visual system, and the first evidence that reorganization affects visual perception. (Abstract shortened by UMI.).

Control of denticle diversity in the Drosophila embryo

Dilks, Stacie A University of Pennsylvania 2010 해외박사(DDOD)

Screening for mutations that affect the epidermal cuticle pattern has been used as a powerful approach to identify genes involved in developmental decisions and signaling pathways (Luschnig et al., 2004; Mayer and Nusslein-Volhard, 1988; Nusslein-Volhard and Wieschaus, 1980). Some years ago, it became clear that the finer details of cuticle pattern, specifically the column-specific differences in denticle shape and hook orientation, occurred as a result of differential activation of the signaling pathways that pattern the epidermis (Alexandre et al., 1999). Since that time, no downstream targets have been identified that selectively affect denticle shape or hooking, and the mechanism(s) involved have remained elusive. Here, we show that the transcription factor stripe integrates signaling information and positional cues to specify multiple aspects of this column-specific denticle pattern, including denticle density and anterior hook orientation. Further, we show that stripe governs hook orientation, in part, via up-regulation of the spectraplakin shot, which functions both cell autonomously and cell non-autonomously to specify denticle hook orientation via interaction with the microtubule cytoskeleton. Thus, the stripe-shot circuit has the potential to link the un-patterned blastoderm to a fully patterned ventral cuticle. It appears that the non-autonomous stripe-shot circuit culminates in the localization of Shot protein across the boundaries where denticle hooks reverse. As spectraplakins can stabilize, localize and bundle microtubule arrays, as well as create specialized membrane domains via membrane protein clustering (Leung et al., 1999; Roper et al., 2002; Sanchez-Soriano, 2009), a likely hypothesis is that Shot organizes a specialized microtubule array or other cytoskeletal complex at these interfaces.

Analysis of maize endosperm endoreduplication

Dilkes, Brian Russell The University of Arizona 2003 해외박사(DDOD)

During maize endosperm development, the cell cycle in the majority of cells switches from a mitotic to an endoreduplication cell cycle. This results in cells of varying ploidies within the tissue, and is presumed to be a factor in its rapid growth. Investigating the inheritance of variation in endoreduplication in maize endosperm will begin to elucidate the genetic mechanisms controlling it. It has been hypothesized that retinoblastoma-related proteins (RRBs) negatively regulate the G1/S transition during both mitotic and endoreduplication cell cycles. Testing this hypothesis in both mitotic cells and endoreduplicating endosperm cells will further our understanding of the molecular mechanisms regulating endoreduplication. Flow cytometry was used to assess the variability of endoreduplication in endosperms of maize inbred lines. High levels of endoreduplication were observed in popcorns relative to Midwestern dent corns. To study the genetic regulation of endoreduplication, four inbreds were crossed to B73 and developing endosperms from parental, reciprocal F1, and backcross generations were subjected to flow cytometric analysis. Maternal zygotic effects, often considered a form of parental imprinting, and maternal sporophytic effects were detected. To test the feasibility of introgressing a high endoreduplication phenotype into a Midwestern dent inbred line, a backcross population was generated using B73 as the reciprocal parent and the popcorn Sg18. The heritabilities calculated from an analysis of the backcross population generally agree with the values calculated in the larger crossing experiments. The Wheat Dwarf Virus RepA protein binds RRBs and is predicted to activate the cell cycle. RepA and the maize RRB, ZmRb1, were tested for cell cycle regulatory activity in tobacco BY-2 cells and determined to be an activator and repressor, respectively. The effect of RepA on endoreduplication was evaluated in both mitotically-active maize callus cultures and developing endosperms. Flow cytometric measurements of nuclear ploidy showed that RepA expression was sufficient to convert a mitotic into an endoreduplication cell cycle in calli but had no discernable effect on endopolyploidy in developing endosperm by 18-days after pollination (DAP).