Evaluation of contact and non-contact trapping efficiencies of human scent chemical profiles and their stabilities under different environmental conditions

Establishing an association between the scent a perpetrator left at a crime scene to the odor of the suspect of that crime is the basis for the use of human scent identification evidence in a court of law. Law enforcement agencies gather evidence through the collection of scent from the objects that a perpetrator may have handled during the execution of the criminal act. The collected scent evidence is consequently presented to the canines for identification line-up procedures with the apprehended suspects. Presently, canine scent identification is admitted as expert witness testimony, however, the accurate behavior of the dogs and the scent collection methods used are often challenged by the court system. The primary focus of this research project entailed an evaluation of contact and non-contact scent collection techniques with an emphasis on the optimization of collection materials of different fiber chemistries to evaluate the chemical odor profiles obtained using varying environment conditions to provide a better scientific understanding of human scent as a discriminative tool in the identification of suspects. The collection of hand odor from female and male subjects through both contact and non-contact sampling approaches yielded new insights into the types of VOCs collected when different materials are utilized, which had never been instrumentally performed. Furthermore, the collected scent mass was shown to be obtained in the highest amounts for both gender hand odor samples on cotton sorbent materials. Compared to non-contact sampling, the contact sampling methods yielded a higher number of volatiles, an enhancement of up to 3 times, as well as a higher scent mass than non-contact methods by more than an order of magnitude. The evaluation of the STU-100 as a non-contact methodology highlighted strong instrumental drawbacks that need to be targeted for enhanced scientific validation of current field practices. These results demonstrated that an individual's human scent components vary considerably depending on the method used to collect scent from the same body region. This study demonstrated the importance of collection medium selection as well as the collection method employed in providing a reproducible human scent sample that can be used to differentiate individuals.

Rank and k-nullity of contact manifolds

We prove that the dimension of the 1-nullity distribution N(1) on a closed Sasakian manifold M of rankl is at least equal to 2l−1 provided that M has an isolated closed characteristic. The result is then used to provide some examples of k-contact manifolds which are not Sasakian. On a closed, 2n+1-dimensional Sasakian manifold of positive bisectional curvature, we show that either the dimension of N(1) is less than or equal to n+1 or N(1) is the entire tangent bundle TM. In the latter case, the Sasakian manifold Mis isometric to a quotient of the Euclidean sphere under a finite group of isometries. We also point out some interactions between k-nullity, Weinstein conjecture, and minimal unit vector fields.

The efficacy of the Ellison model as a retention initiative for first semester freshmen

The freshman year is the most critical year of matriculation for students in higher education. One in four freshman students drops out of higher education after the first year. In fact, the first two to six weeks of college represent a very critical transition period when students make the decision to persist or depart from the institution. Many students leave because they are unable to make a connection with the institution. Retention is often profoundly affected by student involvement in the academic environment, satisfaction with the campus climate and the institution's response to diversity. Therefore, the purpose of this study was to examine and evaluate an effective institutional response that promotes freshman retention and academic success. The tenets (diversity training, conflict management, and community building) of a mentoring model were applied to the freshman experience seminar class (experimental group) as a pedagogical method of instruction to determine its efficacy as a retention initiative when compared with the traditional freshman experience seminar class (comparison group). ^ The quantitative study employed a quasi-experimental research design based on Astin's (1993) I-E-O model. The model examined the relationships between the characteristics students bring with them to college, called inputs, their experiences in the environment during college, and the outcomes students achieved during matriculation. Fifty-two students enrolled in the freshman seminar class participated in the study. ^ Demographic data and input variables between groups were analyzed using chi-square, t-tests and multivariate analyses. Overall, students in the experimental group had significantly higher satisfaction (campus climate) scores than the comparison group. An analysis of the students' willingness to interact with others from diverse groups indicated a significant difference between groups, with the experimental group scoring higher than the comparison group. Students in the experimental group were significantly more involved in campus activities than students in the comparison group. No significant differences were found between groups relative to the mean grade point average and re-enrollment for fall semester 2001. ^ While the mentoring model did not directly affect re-enrollment of students, the model did promote student satisfaction with the institution, an appreciation for diversity of contact and it encouraged involvement in the campus community. These are all essential outcomes of a quality retention program. ^

Effects of academic integration on the persistence and achievement of under-prepared college students

The purpose of this dissertation was to examine the effect of academic integration, defined in terms of instructor/student contact, on the persistence of under-prepared college students and the achievement of those who persist. The overall design of this study compared instructor-initiated contact with conventional contact. The dependent variables were persistence, achievement, motivation and anxiety. Information was collected by administering the College-Level Mathematics Test (CLM), the Perceived Affective Contact Questionnaire (PAC), the expectancy and anxiety components of the Motivated Strategies for Learning Questionnaire (MSLQ), a departmental final examination, and by accessing university records. The sample consisted of 130 college algebra students at a large, public university with a Hispanic majority. The main analyses consisted of a 2 x 2 x 2 ANOVA (treatment by ethnicity by gender) to test for differences in achievement, t-tests to compare motivation, anxiety and perceived affective contact scores for the two groups, Chi-square tests to assess differences in persistence, and Pearson Product-Moment Correlation to determine the relationship between pretest scores and achievement variables. Results indicated that neither instructor-initiated contact, gender nor ethnicity is related to persistence, motivation or anxiety. A significant disordinal interaction of treatment and ethnicity was observed, with Hispanic experimental students scoring significantly higher on a test of algebra achievement than Hispanic control students. ^ Academic integration, defined in terms of instructor/student contact, has a positive influence on the achievement of Hispanic students. This may imply their positive responsiveness to the relational aspect of contact due to traditional cultural values of interdependence, acquiescence to authority and physical closeness. Such interactive feedback is a means by which students with these values are recognized as members of the university academic community, prompting increased academic effort. Training in contact initiation to promote academic integration is implied, by the results of this study, for instructors dealing with first year students, especially instructors at institutions accommodating instructional methods to the needs of diverse groups. ^

Design and fabrication of two switched superconductivity microstrip hairpin filters using series micro-electro-mechanical systems (MEMS) switches

Series Micro-Electro-Mechanical System (MEMS) switches based on superconductor are utilized to switch between two bandpass hairpin filters with bandwidths of 365 MHz and nominal center frequencies of 2.1 GHz and 2.6 GHz. This was accomplished with 4 switches actuated in pairs, one pair at a time. When one pair was actuated the first bandpass filter was coupled to the input and output ports. When the other pair was actuated the second bandpass filter was coupled to the input and output ports. The device is made of a YBa2Cu 3O7 thin film deposited on a 20 mm x 20 mm LaAlO3 substrate by pulsed laser deposition. BaTiO3 deposited by RF magnetron sputtering in utilized as the insulation layer at the switching points of contact. These results obtained assured great performance showing a switchable device at 68 V with temperature of 40 K for the 2.1 GHz filter and 75 V with temperature of 30 K for the 2.6 GHz hairpin filter. ^

In-Vivo Corrosion and Fretting of Modular TI-6AL-4V/CO-CR-MO Hip Prostheses: The Influence of Microstructure and Design Parameters

The purpose of this study was to evaluate the incidence of corrosion and fretting in 48 retrieved titanium-6aluminum-4vanadium and/or cobalt-chromium-molybdenum modular total hip prosthesis with respect to alloy material microstructure and design parameters. The results revealed vastly different performance results for the wide array of microstructures examined. Severe corrosion/fretting was seen in 100% of as-cast, 24% of low carbon wrought, 9% of high carbon wrought and 5% of solution heat treated cobalt-chrome. Severe corrosion/fretting was observed in 60% of Ti-6Al-4V components. Design features which allow for fluid entry and stagnation, amplification of contact pressure and/or increased micromotion were also shown to play a role. 75% of prosthesis with high femoral head-trunnion offset exhibited poor performance compared to 15% with a low offset. Large femoral heads (>32mm) did not exhibit poor corrosion or fretting. Implantation time was not sufficient to cause poor performance; 54% of prosthesis with greater than 10 years in-vivo demonstrated none or mild corrosion/fretting.

Effects of academic integration on the persistence and achievement of under-prepared college students

The purpose of this dissertation was to examine the effect of academic integration, defined in terms of instructor/student contact, on the persistence of under-prepared college students and the achievement of those who persist. The overall design of this study compared instructor-initiated contact with conventional contact. The dependent variables were persistence, achievement, motivation and anxiety. Information was collected by administering the College-Level Mathematics Test (CLM), the Perceived Affective Contact Questionnaire (PAC), the expectancy and anxiety components of the Motivated Strategies for Learning Questionnaire (MSLQ), a departmental final examination, and by accessing university records. The sample consisted of 130 college algebra students at a large, public university with a Hispanic majority. The main analyses consisted of a 2x2x2 ANOVA (treatment by ethnicity by gender) to test for differences in achievement, t-tests to compare motivation, anxiety and perceived affective contact scores for the two groups, Chi-square tests to assess differences in persistence, and Pearson Product-Moment Correlation to determine the relationship between pretest scores and achievement variables. Results indicated that neither instructor-initiated contact, gender nor ethnicity is related to persistence, motivation or anxiety. A significant disordinal interaction of treatment and ethnicity was observed, with Hispanic experimental students scoring significantly higher on a test of algebra achievement than Hispanic control students. Academic integration, defined in terms of instructor/student contact, has a positive influence on the achievement of Hispanic students. This may imply their positive responsiveness to the relational aspect of contact due to traditional cultural values of interdependence, acquiescence to authority and physical closeness. Such interactive feedback is a means by which students with these values are recognized as members of the university academic community, prompting increased academic effort. Training in contact initiation to promote academic integration is implied, by the results of this study, for instructors dealing with first year students, especially instructors at institutions accommodating instructional methods to the needs of diverse groups.