The development of internet is creating intense competition in social network sites nowadays. How to conduct users¡¦ loyalty to social network sites gradually becomes an important issue to operate long-term social network sites. The study attempts to examine how consumers¡¦ utilitarian value, hedonic value and social value affect their loyalty. Furthermore, this study examines whether the relationship is mediated by gender difference. The model and relationship are tested and validated by using PLS and data collected from 200 people having facebook accounts in Taiwan. The results shows that loyalty is strongly affected by utilitarian value, hedonic value and social value. We also find that the difference of gender has positive influence on hedonic value and loyalty and negative influence on social value and loyalty. The implication for research and practice are also discussed.

The objective of this longitudinal study was to study the relationship between changes in prevalence of resistant enteric bacteria associated with mean monthly doses (MMD) of various antibiotics used in each of two host species. From January 2004 – January 2007, monthly composite swine fecal samples and human wastewater samples representing various production and occupational cohorts, respectively, were collected from 19 geographically unique locations in east- and south-central Texas. Bacterial isolates cultivated on CHROMagar-E.coliTM and DifcoTM mEnterococcus (ME) were tested for susceptibility to multiple antibiotics by microbroth dilution using the SensititreTM system. The relationship between the prevalence of resistant bacteria, sampling period, and antibiotic use within each host species was assessed in a generalized linear model adjusted for the dependence of responses within location using a binomial distribution and logit link function in STATA® ver. 9.2. For the swine E. coli isolates, the relationship between tetracycline resistance and level of chlortetracycline (CTC) use in swine illustrated a dose-response relationship, with odds ratios (OR) of 1.20 and 1.81 (P < 0.05) for second- and third-level categories of MMD relative to baseline (zero-use) respectively. When considered by swine production groups, intake boar isolates had an elevated relative odds of resistance to tetracycline (OR = 1.51, P < 0.05), and the nursery units had an elevated odds (OR = 2.61, P < 0.05) of exhibiting resistance to ceftiofur, relative to pigs housed in the farrowing barns. Regarding swine Enterococci isolates, those swine from locations that utilized tylosin had an elevated OR of 3.54 (P < 0.05) of exhibiting resistance to tylosin, relative to those locations that used no tylosin. At this juncture, an apparent occupational risk of harboring tetracycline-resistant E. coli, and the apparent sparing effect (Enterococcus spp.) associated with exposure to swine production, remain unexplained. This study demonstrated that the prevalences of tetracycline- and tylosin-resistant enteric bacteria swine were dependent on CTC and tylosin use in feed, respectively. Swine production group-effects on the prevalence of tetracycline, ceftiofur, and erythromycin resistance were also important. This study provides a better understanding of the relationships between antibiotic prescribing practices at the ecologic level and the relative odds of carriage of resistant bacteria within two host species in a vertically integrated agri-food system.

Phosphotriesterase (PTE) from Pseudomonas diminuta is a zinc metalloenzyme found in soil bacteria capable of organophosphate hydrolysis at rates approaching the diffusion controlled limit. Interest in PTE for degradation of chemical warfare agents and disposal of pesticides supports the need to understand the mechanism by which it performs hydrolysis. For further mechanistic clarity, this work will provide direct confirmation of the solvent bridge identity and the protonated species resulting in loss of catalytic identity. Inhibitor and product binding to the metal center will also be addressed; as well as the evaluation of the catalytic activity of Fe(II)-substituted PTE. This work has determined that the Mn/Mn-PTE electron paramagnetic resonance (EPR) spectrum exhibits exchange coupling that is facilitated through a hydroxide bridge. Protonation of the bridging hydroxide results in the loss of the exchange coupling between the two divalent cations and the loss of catalytic activity. The reversible protonation of the bridging hydroxide has an apparent pKa of 7.3 based upon changes in the EPR spectrum of Mn/Mn-PTE with alterations in pH. The pH-rate profile for the hydrolysis of paraoxon by Mn/Mn-PTE shows the requirement of a single function group that must be unprotonated with a pKa of 7.1. The comparable pKa values are proposed to result from the protonation of the same ionizable species. The effects of inhibitor and product binding on the magnetic properties of the metal center and the hydroxyl bridge are investigated by accessing new EPR spectral features. This work concludes that the binding of inhibitor occurs at the metal center and results in an increase of non-bridged hydroxyl species. These results, in conjunction with kinetic and crystallographic data, suggest that substrate binding via the phosphoryl oxygen at the ?-metal weakens the hydroxyl bridge coordination to the ?-metal. This loss of coordination would increase the nucleophilic character of the bridge, and binding of the substrate to the metal center would result in a stronger nucleophile for hydrolysis. Lastly, Fe(II) binding and activation of apoenzyme is evaluated under anaerobic conditions. This work concludes Fe/Fe-PTE is not catalytically active, but can bind up to 2 equivalent Fe(II) ions per active site.

Recent improvements in structural genomics efforts have greatly increased the number of hypothetical proteins in the Protein Data Bank. Several computational methodologies have been developed to determine the function of these proteins but none of these methods have been able to account successfully for the diversity in the sequence and structural conformations observed in proteins that have the same function. An additional complication is the flexibility in both the protein active site and the ligand. In this dissertation, novel approaches to deal with both the ligand flexibility and the diversity in stereochemistry have been proposed. The active site analysis problem is formalized as a classification problem in which, for a given test protein, the goal is to predict the class of ligand most likely to bind the active site based on its stereochemical nature and thereby define its function. Traditional methods that have adapted a similar methodology have struggled to account for the flexibility observed in large ligands. Therefore, I propose a novel fragment-based approach to dealing with larger ligands. The advantage of the fragment-based methodology is that considering the protein-ligand interactions in a piecewise manner does not affect the active site patterns, and it also provides for a way to account for the problems associated with flexible ligands. I also propose two feature-based methodologies to account for the diversity observed in sequences and structural conformations among proteins with the same function. The feature-based methodologies provide detailed descriptions of the active site stereochemistry and are capable of identifying stereochemical patterns within the active site despite the diversity. Finally, I propose a Markov Random Field approach to combine the individual ligand fragment classifications (based on the stereochemical descriptors) into a single multi-fragment ligand class. This probabilistic framework combines the information provided by stereochemical features with the information regarding geometric constraints between ligand fragments to make a final ligand class prediction. The feature-based fragment identification methodology had an accuracy of 84% across a diverse set of ligand fragments and the mrf analysis was able to succesfully combine the various ligand fragments (identified by feature-based analysis) into one final ligand based on statistical models of ligand fragment distances. This novel approach to protein active site analysis was additionally tested on 3 proteins with very low sequence and structural similarity to other proteins in the PDB (a challenge for traditional methods) and in each of these cases, this approach successfully identified the cognate ligand. This approach addresses the two main issues that affect the accuracy of current automated methodologies in protein function assignment.

The primary objectives of this research are to identify the relation between Leadership in Energy and Environmental Design (LEED) criteria regarding sustainable site credits and the appraised value of land parcels in the City of Houston, and additionally to analyze the effects of detail components which leverage the sustainable credits regarding the Public Transportation Access (PTA) in terms of economic issues. To accomplish these objectives, the approach to estimate sustainable ratings of specific parcels using Geographic Information Systems (GIS) was established. Green construction must be one of the most powerful trends in the construction industry. One of the main concepts to underlie the basis of this green construction is sustainability. This sustainability has to be considered in the process of the site selection prior to the actual activities to construct a building. Recently, the U.S. Green Building Council (USGBC) has suggested the modified guideline with "LEED 2009 for New Construction and Major Renovations". According to this metric, it is clear that this principle endeavors to block environmental abuses related to land development or restoration projects. On the other hand, it is not easy to check the serviceability of these rules to guarantee continuous economic merit through sustainable land development or restoration encouraged by these criteria. The criteria regarding the sustainable site selection in this LEED metric are Sustainable Site Credit (SSC) #1: Site Selection, SSC #3: Brownfield, and SSC #4.1: Public Transportation Access. Linear regression methods were used for predictive analysis. In this model, the unit appraisal value of the land was used as the dependent variable to reflect the economic values of the land, and LEED-sustainable-site criteria were used as the categorical independent variables. According to statistical results, the models to predict the appraisal parcel value using sustainable site components have relatively low R-square. Moreover, SSC #1 and SSC #3 were not significant factors affecting the unit value of land. This outcome means that there are no statistically significant effects of SSC #1 and SSC #3 on parcel value. On the other hand, SSC #4.1 was highly significant. Furthermore, the detail components of SSC #4.1 regarding the bus stops and railroad stations were also significant. These results can lead to improved environmental preservation by avoiding development which is far from the PTA as well as increasing economic value while enhancing the development density near the PTA corridors. Finally, GIS was used to determine the LEED ratings of individual parcels. The methods established to do this can be applied to other projects for the other regions, or the same region at different times.

It was usual that museums built up their won Web sites nowadays. However, building Web sites didn¡¦t mean that museums used Internet to support museums¡¦ operation. In researcher¡¦s opinion, using Internet services had become an indivisible part of modern life. Since researches on private museums was less than those on famous and public museums, this study used the ICDT model ¡]four virtual space, included information, communication, distribution, and transaction¡^and the Content Analysis to point out the dimension and the level of digitalization of 97 museum Web sites. This study result could be used to suggest museum operating Web sites and providing e-services in an excellent way. The study result included the following guidelines: 1¡EThe information-and-commerce-based Web sites presented more consistency than those of information-based Web sites. The information-and-commerce-based Web sites also presented higher level of digitalization. 2¡EThe museum Web sites should provide information of abundance and depth, use multiple online communication functions, develop Internet as a new distribution, and pay more attention to the security of transaction and individual¡¦s privacy. 3¡EThe problem of digitalization of private museums was the unclear idea of digitalization and Web site, as well as the unrealized needs of museums and Internet users. In suggestion, the museum should find out attributes that differed from the others, and set up the Web site¡¦s main notion according to museum mission. Further more, to match museum¡¦s needs and user¡¦s needs, so as to seek for corporation of other business and resources. Finally, to keep well maintenance and evaluation of Web sites.

none

This study is more or less of an exploratory research style. It is aimed to find out what the impact of the travel information appearing on a company web site that is run by a travel agent, upon traditional customers in a sense of interactive marketing. It is hoped that through the subject study we can much understand traditional customer expectations and perceptions in using of the internet. It would also equip the agents in a better position to fulfill the customer requirements when they map out the content of the travel company web site and implement the information communication. And finally it will lead to the best marketing strategy planning.

Two deeply buried, well-stratified, and well-dated components dating to the Early Holocene period were excavated at the Richard Beene site (41BX831) in Bexar County, Texas. This thesis utilizes both qualitative (interpretation of maps) and quantitative (unconstrained clustering) spatial analysis techniques to identify site structure and assess post-depositional disturbance by analyzing patterns among artifact categories, selected artifacts, and features from these components. Results of spatial analysis are compared to expectations of the archaeological record based on previous research. Each component revealed a distinct pattern. The Lower Medina component (ca. 6900 B.P.) is well preserved and spatial analysis showed clear distinctions between domestic and peripheral zones. The Upper Perez component (8800 B.P.) is a fluvial lag deposit of displaced artifacts and fire-cracked rock features. Results of spatial analysis confirmed that most, if not all, of this component is disturbed, revealing no site structure.

Texas A&M University (TAMU) supports a substantial breeding population of mourning doves (Zenaida macroura) with one of the highest nest densities in Texas. There has been a long history of mourning dove research on the TAMU Campus, with initial population studies conducted in the 1950’s, and the most recent studies occurring in the 1980’s. The TAMU Campus and surrounding areas have experienced substantial changes associated with urbanization and expansion over the last 50 years, altering mourning dove habitat on and around campus. The objective of this study was to examine mourning dove nesting and production in an urban setting and determine how microhabitat and landscape features affect nest-site selection and nest success. Specifically, I (1) examined trends in mourning dove nesting density and nest success on the TAMU Campus, and (2) identified important microhabitat and landscape features associated with nest-site selection and nesting success. Mourning dove nests were located by systematically searching potential nest sites on a weekly basis from the late-March through mid-September. Nests were monitored until they either failed or successfully fledged at least 1 young. A total of 778 nests was located and monitored on campus. All nest locations were entered into ArcView GIS. An equal number of nests were randomly generated in ArcView and assigned to non-nest trees to evaluate habitat variables associated with nest-site selection for mourning doves. Binary logistic regression was used to evaluate the significance of microhabitat and landscape variables to nest-site selection and nest success. Comparisons with data collected in 1950, 1978, and 1979 showed relatively similar nesting densities, but a significant decrease in nest success over time. A comparison of microhabitat features between actual nest trees and random locations (non-nest trees) indicated increasing values of tree diameter at breast height and tree species were important predictors of mourning dove nest-site selection. Landscape features found important in dove nest-site selection were proximity to open fields, roads, and buildings. Proximity to roads and buildings also were significant predictors of nest success. Combining significant microhabitat and landscape variables for nest-site selection increased the predictability of the model indicating a possible hierarchical nest-site selection strategy.