Development of a medium-capacity guideway transit planning guide

Rapid population increase and booming economic growth have caused a significant escalation in car ownership in many cities, leading to additional or, multiple traffic problems on congested roadways. The increase of automobiles is generating a significant amount of congestion and pollution in many cities. It has become necessary to find a solution to the ever worsening traffic problems in our cities. Building more roadways is nearly impossible due to the limitations of right-of-way in cities. Studies have shown that guideway transit could provide effective transportation and could stimulate land development. The Medium-Capacity Guideway Transit (MCGT) is one of the alternatives to solve this problem. The objective of this research was to better understand the characteristics of MCGT systems, to investigate the existing MCGT systems around the world and determine the main factors behind the planning of successful systems, and to develop a MCGT planning guide. The factors utilized in this study were determined and were analyzed using Excel. A MCGT Planning Guide was developed using Microsoft Visual Basic. ^ A MCGT was defined as a transit system whose capacity can carry up to 20,000 passengers per hour per direction (pphpd). The results shown that Light Rail Transit (LRT) is favored when peak hour demand is less than 13,000 pphpd. Automated People Mover (APM) is favored when the peak hour demand is more than 18,000 pphpd. APM systems could save up to three times the waiting time cost compared to that of the LRT. If comfort and convenience are important, then using an APM does make sense. However, if cost is the critical factor, then LRT will make more sense because it is reasonable service at a reasonable price. If travel time and safety (accident/crush) costs were included in calculating life-cycle “total” costs, the capital cost advantage of LRT disappeared and APM could become very competitive. The results also included a range of cost-performance criteria for MCGT systems that help planners, engineers, and decision-makers to select the most feasible system for their respective areas. ^

The interactive effects of predators, resources, and disturbance on freshwater snail populations from the Everglades

The origins of population dynamics depend on interplay between abiotic and biotic factors; the relative importance of each changing across space and time. Predation is a central feature of ecological communities that removes individuals (consumption) and alters prey traits (non-consumptive). Resource quality mitigates non-consumptive predator effects by stimulating growth and reproduction. Disturbance resets predator-prey interactions by removing both. I integrate experiments, time-series analysis, and performance trials to examine the relative importance of these on the population dynamics of a snail species by studying a variety of their traits. A review of ninety-three published articles revealed that snail abundance was much less in the Everglades and similar ecosystems compared to all other freshwater ecosystems considered. Separating consumptive from non-consumptive (cues) predator effects at different phosphorous levels with an experiment determined that phosphorous stimulated, but predator cues inhibited snail growth (34% vs. 23%), activity (38% vs. 53%), and reproductive effort (99% vs. 90%) compared to controls. Cues induced taller shells and smaller openings and moved to refugia where they reduced periphyton by 8%. Consumptive predator effects were minor in comparison. In a reciprocal transplant cage experiment along a predator cue and phosphorous gradient created by a canal, snails grew 10% faster and produced 37% more eggs far from the canal (fewer cues) when fed phosphorous-enriched periphyton from near the canal. Time-series analysis at four sites and predator performance trials reveal that phosphorous-enriched regions support larger snail populations, seasonal drying removes snails at all sites, crayfish negatively affect populations in enriched regions, and molluscivorous fish consume snails in the wet season. Combining these studies reveals interplay between resources, predators, and seasonality that limit snail populations in the Everglades and lead to their low abundance compared to other freshwater ecosystems. Resource quality is emerging as the critical factor because improving resources profoundly improved growth and reproduction; seasonal drying and predation become important at times and places. This work contributes to the general understanding in ecology of the relative importance of different factors that structure populations and provides evidence that bolsters monitoring efforts to assess the Comprehensive Everglades Restoration Plan that show phosphorous enrichment is a major driver of ecosystem change.

Engagement experiences of Hispanic Generation 1.5 English language learners at a Massachusetts community college

Hispanic Generation 1.5 students are foreign-born, U.S. high school graduates who are socialized in the English dominant K-12 school system while still maintaining the native language and culture at home (Allison, 2006; Blumenthal, 2002; Harklau, Siegal, & Losey, 1999; Rumbault & Ima, 1988). When transitioning from high school to college, these students sometimes assess into ESL courses based on their English language abilities, and because of this ESL placement, Hispanic Generation 1.5 students might have different engagement experiences than their mainstream peers. Engagement is a critical factor in student success and long-term retention because students’ positive and negative engagement experiences affect their membership and sense of belonging at the institution. The purpose of this study was to describe the engagement and membership experiences of Hispanic Generation 1.5 students’ at a Massachusetts community college. This study employed naturalistic inquiry within an embedded descriptive case study design that included three units of analysis: the students’ engagement experiences in (a) ESL courses, (b) developmental courses, and (c) mainstream courses. The main source of data was in-depth interviews with Hispanic Generation 1.5 students at Commonwealth of Massachusetts Community College. Criterion sampling was used to select the interview participants, ensuring that all participants were native Spanish speakers and were taking or had taken at least one ESL course at the institution. The study findings show that these Hispanic Generation 1.5 students at the college did not perceive peer engagement as critical to academic success. Most times the participants avoided peer engagement outside of the classroom, especially with fellow Hispanic students, who they felt would deter them from their English language development and general academic work. Engagement with ESL faculty and ESL academic support staff played the most critical role in the participants’ sense of belonging and success, and students who were required to engage with faculty and academic support staff outside of the classroom were the most satisfied with their educational experiences. While the participants were all disappointed with some aspect of their ESL placement, they valued the ESL engagement experiences more than the engagement experiences while completing developmental and credit coursework.

A quantitative approach to the organizational design problem

The span of control is the most discussed single concept in classical and modern management theory. In specifying conditions for organizational effectiveness, the span of control has generally been regarded as a critical factor. Existing research work has focused mainly on qualitative methods to analyze this concept, for example heuristic rules based on experiences and/or intuition. This research takes a quantitative approach to this problem and formulates it as a binary integer model, which is used as a tool to study the organizational design issue. This model considers a range of requirements affecting management and supervision of a given set of jobs in a company. These decision variables include allocation of jobs to workers, considering complexity and compatibility of each job with respect to workers, and the requirement of management for planning, execution, training, and control activities in a hierarchical organization. The objective of the model is minimal operations cost, which is the sum of supervision costs at each level of the hierarchy, and the costs of workers assigned to jobs. The model is intended for application in the make-to-order industries as a design tool. It could also be applied to make-to-stock companies as an evaluation tool, to assess the optimality of their current organizational structure. Extensive experiments were conducted to validate the model, to study its behavior, and to evaluate the impact of changing parameters with practical problems. This research proposes a meta-heuristic approach to solving large-size problems, based on the concept of greedy algorithms and the Meta-RaPS algorithm. The proposed heuristic was evaluated with two measures of performance: solution quality and computational speed. The quality is assessed by comparing the obtained objective function value to the one achieved by the optimal solution. The computational efficiency is assessed by comparing the computer time used by the proposed heuristic to the time taken by a commercial software system. Test results show the proposed heuristic procedure generates good solutions in a time-efficient manner.

Comparison of Belowground Biomass in C3- and C4-Dominated Mixed Communities in a Chesapeake Bay Brackish Marsh

Belowground biomass is a critical factor regulating ecosystem functions of coastal marshes, including soil organic matter (SOM) accumulation and the ability of these systems to keep pace with sea-level rise. Nevertheless, belowground biomass responses to environmental and vegetation changes have been given little emphasis marsh studies. Here we present a method using stable carbon isotopes and color to identify root and rhizomes of Schoenoplectus americanus (Pers.) Volk. ex Schinz and R. Keller (C3) and Spartina patens (Ait.) Muhl. (C4) occurring in C3− and C4-dominated communities in a Chesapeake Bay brackish marsh. The functional significance of the biomass classes we identified is underscored by differences in their chemistry, depth profiles, and variation in biomass and profiles relative to abiotic and biotic factors. C3 rhizomes had the lowest concentrations of cellulose (29.19%) and lignin (14.43%) and the lowest C:N (46.97) and lignin:N (0.16) ratios. We distinguished two types of C3 roots, and of these, the dark red C3 roots had anomalously high C:N (195.35) and lignin:N (1.14) ratios, compared with other root and rhizome classes examined here and with previously published values. The C4-dominated community had significantly greater belowground biomass (4119.1 g m−2) than the C3-dominated community (3256.9 g m−2), due to greater total root biomass and a 3.6-fold higher C3-root:rhizome ratio in the C4-dominated community. C3 rhizomes were distributed significantly shallower in the C4-dominated community, while C3 roots were significantly deeper. Variability in C3 rhizome depth distributions was explained primarily by C4 biomass, and C3 roots were explained primarily by water table height. Our results suggest that belowground biomass in this system is sensitive to slight variations in water table height (across an 8 cm range), and that the reduced overlap between C3 and C4 root profiles in the C4-dominated community may account for the greater total root biomass observed in that community. Given that future elevated atmospheric CO2 and accelerated sea-level rise are likely to increase C3 abundance in Atlantic and Gulf coast marshes, investigations that quantify how patterns of C3 and C4 belowground biomass respond to environmental and biological factors stand to improve our understanding of ecosystem-wide impacts of global changes on coastal wetlands.

The mediating effect of innovation on the relationship between corporate reputation and performance in U.S. firms

In recent years, corporate reputation has gained the attention of many scholars in the strategic management and related fields. There is a general consensus that higher corporate reputation is positively related to firm success or performance. However, the link is not always straightforward; as a result, it calls for researchers to dedicate their efforts to investigate the causes and effects of firm reputation and how it is related to performance. In this doctoral dissertation, innovation is suggested as a mediating variable in this relationship. Innovation is a critical factor for firm success and survival. Highly reputed firms are in a more advantageous position to attract critical resources for innovation such as human and financial capital. These firms face constant pressure from external stakeholders, e.g. the general public, or customers, to achieve and remain at high levels of innovativeness. As a result, firms are in constant search, internally or externally, for new technologies expanding their knowledge base. Consequently, these firms engage in firms acquisitions. In the dissertation, the author assesses the effects of domestic versus international acquisitions as well as related versus unrelated acquisitions on the level of innovativeness and performance. Building upon an established measure of firm-level degree of internationalization (DOI), the dissertation proposes a more detailed and enhanced measure for the firm's DOI. It is modeled as an interaction effect between corporate reputation and resources for innovation. More specifically, firms with higher levels of internationalization will have access to resources for innovation, i.e. human and financial capital, at a global scale. Additionally, the distance between firms and higher education institutions, i.e. universities, is considered as another interaction effect for the human capital attraction. The dissertation is built on two theoretical frameworks, the resource-based view of the firm and institutional theory. It studies 211 U.S. firms using a longitudinal panel data structure from 2006 to 2012. It utilizes a linear dynamic panel data estimation methodology for its hypotheses analyses. Results confirm the hypotheses proposed in the study.

A Critical Review of the Implied Cost of Equity: A New Way to Estimate the Expected Return

For the last three decades, the Capital Asset Pricing Model (CAPM) has been a dominant model to calculate expected return. In early 1990% Fama and French (1992) developed the Fama and French Three Factor model by adding two additional factors to the CAPM. However even with these present models, it has been found that estimates of the expected return are not accurate (Elton, 1999; Fama &French, 1997). Botosan (1997) introduced a new approach to estimate the expected return. This approach employs an equity valuation model to calculate the internal rate of return (IRR) which is often called, 'implied cost of equity capital" as a proxy of the expected return. This approach has been gaining in popularity among researchers. A critical review of the literature will help inform hospitality researchers regarding the issue and encourage them to implement the new approach into their own studies.

The role of the transcription factor Ets1 in melanocyte development

Melanocytes, pigment-producing cells, derive from the neural crest (NC), a population of pluripotent cells that arise from the dorsal aspect of the neural tube during embryogenesis. Many genes required for melanocyte development were identified using mouse pigmentation mutants. The deletion of the transcription factor Ets1 in mice results in hypopigmentation; nevertheless, the function of Ets1 in melanocyte development is unknown. The goal of the present study was to establish the temporal requirement and role of Ets1 in murine melanocyte development. In the mouse, Ets1 is widely expressed in developing organs and tissues, including the NC. In the chick cranial NC, Ets1 is required for the expression of Sox10, a transcription factor critical for the development of melanocytes, enteric ganglia, and other NC derivatives. ^ Using a combination of immunofluorescence and cell survival assays Ets1 was found to be required between embryonic days 10 and 11, when it regulates NC cell and melanocyte precursor (melanoblast) survival. Given the requirement of Ets1 for Sox10 expression in the chick cranial NC, a potential interaction between these genes was investigated. Using genetic crosses, a synergistic genetic interaction between Ets1 and Sox10 in melanocyte development was found. Since Sox10 is essential for enteric ganglia formation, the importance of Ets1 on gut innervation was also examined. In mice, Ets1 deletion led to decreased gut innervation, which was exacerbated by Sox10 heterozygosity. ^ At the molecular level, Ets1 was found to activate a Sox10 enhancer critical for Sox10 expression in melanoblasts. Furthermore, mutating Ets1 at a site I characterized in the spontaneous variable spotting mouse pigmentation mutant, led to a 2-fold decrease in enhancer activation. Overexpression and knockdown of Ets1 did not affect Sox10 expression; nonetheless, Ets1 knockdown led to a 6-fold upregulation of the transcription factor Sox9, a gene required for melanocyte and chondrocyte development, but which impairs melanocyte development when its expression is prolonged. Together, these results suggest that Ets1 is required early during melanocyte development for NC cell and melanoblast survival, possibly acting upstream of Sox10. The transcription factor Ets1 may also act indirectly in melanocyte fate specification by repressing Sox9 expression, and consequently cartilage fate.^

Critical problem solving scale : creating and choosing alternative solutions

This thesis extends previous research on critical decision making and problem-solving by refining and validating a self-report measure designed to assess the use of critical decision making and problem solving in making life choices. The analysis was conducted by performing two studies, and therefore collecting two sets of data on the psychometric properties of the measure. Psychometric analyses included: item analysis, internal consistency reliability, interrater reliability, and an exploratory factor analysis. This study also included regression analysis with the Wonderlic, an established measure of general intelligence, to provide preliminary evidence for the construct validity of the measure.

The Role of the Transcription Factor Ets1 in Melanocyte Development

Melanocytes, pigment-producing cells, derive from the neural crest (NC), a population of pluripotent cells that arise from the dorsal aspect of the neural tube during embryogenesis. Many genes required for melanocyte development were identified using mouse pigmentation mutants. The deletion of the transcription factor Ets1 in mice results in hypopigmentation; nevertheless, the function of Ets1 in melanocyte development is unknown. The goal of the present study was to establish the temporal requirement and role of Ets1 in murine melanocyte development. In the mouse, Ets1 is widely expressed in developing organs and tissues, including the NC. In the chick cranial NC, Ets1 is required for the expression of Sox10, a transcription factor critical for the development of melanocytes, enteric ganglia, and other NC derivatives. Using a combination of immunofluorescence and cell survival assays Ets1 was found to be required between embryonic days 10 and 11, when it regulates NC cell and melanocyte precursor (melanoblast) survival. Given the requirement of Ets1 for Sox10 expression in the chick cranial NC, a potential interaction between these genes was investigated. Using genetic crosses, a synergistic genetic interaction between Ets1 and Sox10 in melanocyte development was found. Since Sox10 is essential for enteric ganglia formation, the importance of Ets1 on gut innervation was also examined. In mice, Ets1 deletion led to decreased gut innervation, which was exacerbated by Sox10 heterozygosity. At the molecular level, Ets1 was found to activate a Sox10 enhancer critical for Sox10 expression in melanoblasts. Furthermore, mutating Ets1 at a site I characterized in the spontaneous variable spotting mouse pigmentation mutant, led to a 2-fold decrease in enhancer activation. Overexpression and knockdown of Ets1 did not affect Sox10 expression; nonetheless, Ets1 knockdown led to a 6-fold upregulation of the transcription factor Sox9, a gene required for melanocyte and chondrocyte development, but which impairs melanocyte development when its expression is prolonged. Together, these results suggest that Ets1 is required early during melanocyte development for NC cell and melanoblast survival, possibly acting upstream of Sox10. The transcription factor Ets1 may also act indirectly in melanocyte fate specification by repressing Sox9 expression, and consequently cartilage fate.