<p> Contemporary aerobic exercise guidelines comprised of continuous durations and higher intensities have been shown to be effective in the prevention and treatment of risk factors associated with obesity and cardiovascular disease (CVD). However, high-intensity interval training (HIIT) has recently been examined as an advantageous protocol for producing more favorable physiological and psychological benefits in comparison to traditional continuous exercise guidelines. The dual-mode model, which examines the dose response relationship between exercise intensity and affective valence, would suggest that exercise performed well above the ventilatory threshold (VT) in the severe domain should result in negative affective valence. </p><p> Numerous investigations have confirmed the reliability of the dual-mode models ability to predict compromised affective valence in the presence of heavy to severe exercise intensities, but only a small amount of research has examined the efficacy of the dual-mode model during HIIT. However, no research to date has combined HIIT with the dual-mode model's efficacy to predict affective valence in target populations challenged by exercise adherence, such as overweight and sedentary individuals. Therefore, the purpose of this study was to examine the dual-mode model's reliability to predict affective valence for overweight and sedentary individuals performing HIIT. </p><p> A total of 14 participants (7 male, 7 female) with a mean age of 23 &plusmn; 4 (range = 18-33) and mean BMI of 29 &plusmn; 3 (range = 25-33) completed the study. Each participant completed a ramp maximal exercise test to determine VT and peak power data, which allowed for specific exercise intensities of delta (DT) to be prescribed for experimental trials. Participants were low to moderate risk. The four experimental conditions were all matched for total work: 1) continuous at 10% DT (Continuous-Heavy - CH), 2) 24 &times; 30-second intervals at 60% DT (Interval-Severe 30 Second - IS30), 3) 12 &times; 60-second intervals at 60% DT (Interval-Severe 60 Second - IS60), 4) 6 &times; 120-second intervals at 60% DT (Interval-Severe 120 Second &ndash; IS120). The continuous exercise condition was 20 minutes in duration, whereas all interval exercise conditions were 24 minutes in duration. </p><p> Results indicated that in-task perceptual responses defined, as affective valence and perceived enjoyment were overall more favorable during IS30 and IS60 in comparison to CH and IS120. IS30 was the only experimental condition in which affective valence did not decline significantly (p > 0.05). Ratings of perceived enjoyment were greater at all measured time points during IS60 (p &lt; 0.05) in comparison to CH. The findings of this study suggest that HIIT comprised of 30 and or 60 seconds help to facilitate more favorable perceptual responses of affective valence and perceived enjoyment than continuous exercise and intervals of longer than 60 seconds duration.</p>

<p> The ability to predict accurately the energy <i>V</i>₀(&rho;) of the quasi-free electron along the entire density <i> V</i>₀(&rho;) range of a supercritical fluid has applications in determining the ideal thermodynamic conditions for chemical reactions involving charged species. The previously established field ionization method of extracting <i> V</i>₀(&rho;) from the fluid density dependent shift &Delta;(&rho;) in the ionization energy of a dopant molecule has led to the discovery of a novel effect on V₀(&rho;) occurring near the critical isotherm of the fluid. Unfortunately this method has limitations in determining <i> V</i>₀(&rho;) in fluids with low critical temperatures as well as fluids opaque to vacuum ultraviolet radiation. Thus, accurate determination of <i>V</i>₀(&rho;) in repulsive fluids (i.e., those possessing a positive zero kinetic energy electron scattering length) using field ionization is difficult. </p><p> The new method developed in this study, namely field enhanced photoemission, allows for the direct determination of the quasi-free electron energy from the density dependent shift in the work function of a metal electrode submerged in the fluid. This mitigates the problems posed by field ionization while producing results with similar precision. Field enhanced photoemission was verified by measuring <i>V</i>₀(&rho;) of Ar, an attractive fluid (i.e., one with a negative zero kinetic energy electron scattering length) studied extensively in the past by field ionization, before applying the method to the study of V₀(&rho;) in the repulsive fluids Ne, He and N₂. The new results showed a distinct critical point effect on <i>V</i>₀(&rho;), which was accurately modeled with the local Wigner-Seitz approach developed for attractive fluids. Thus, this work extends our theoretical model to repulsive fluids. </p><p> Unlike the attractive fluids studied in the past, the quasi-free electron energy in the repulsive fluids presented here is strictly positive. A careful analysis of the terms contributing to <i>V</i>₀(&rho;) within the local Wigner-Seitz model leads one to expect the quasi-free electron energy to be positive in repulsive fluids in general. A discussion of fluid density dependent behavior of the kinetic and potential energy terms contributing to <i>V</i>₀(&rho;) is presented along with an explanation of the evolution of the shape of the <i>V</i>₀(&rho;) curves for the fluids studied.</p>

<p>Western Long Island Sound (WLIS) bottom waters experience low dissolved oxygen (DO) levels in the summertime. The seasonal hypoxia in the WLIS motivated the development of a coupled biogeochemistry/hydrodynamic model named the System Wide Eutrophication Model (SWEM). A critical assessment of the SWEM model, however, reveals that vertical transport rates are grossly underestimated, indicating a need for data-based estimates of these rates. </p><p> I present a novel approach to estimate vertical mixing coefficients from time-series of measurements made at two or more depths by measuring the attenuation and phase lag of scalar signals generated periodically at the surface as they propagate downwards and estimate mean summertime depth-averaged downward fluxes of DO and heat of 14&plusmn;4 &mu;M day^&ndash;1 and 17&plusmn;10 Wm^&ndash;3, respectively. In order to assess the importance of horizontal transport in the bottom waters, I present an analysis of time-series of moored temperature, DO, and current observations in the hypoxic area of Long Island Sound and estimate mean near-bottom along-channel flux differences of DO and heat as 4&plusmn;6 &mu;M day^&ndash;1 and &ndash;5&plusmn;6 Wm^&ndash;3, respectively. I conclude that vertical transport forms the bulk of the physical supply of both DO and heat to the hypoxic zone. </p><p> When WLIS moored instrument records are examined, it is evident that near-bottom increases in DO and heat and a decrease in salt occur during the middle of the flood tide; an analysis of water mass signatures indicates that the transport involved is vertical and not horizontal. Temperature data from a thermistor string deployed in the WLIS for 16 days in August 2009 clearly shows internal waves and a pycnocline depression of approximately 25% of the water depth occurring at mid-flood. Near-bottom internal wave energy is correlated with near-bottom DO and temperature changes at both supertidal and subtidal scales, and I conclude that internal mechanisms are potentially important to vertical transport in the WLIS region. </p>

<p> The chin, or mentum osseum, is regarded as one of the most unique traits that differentiate modern humans from our earlier hominin ancestors and has received intense scrutiny by scholars for well over a century. Several hypotheses are currently being investigated by researchers in attempts to elucidate the nature of the origin and function of the chin, but none of these have been satisfactorily upheld. Additionally, there are debates about what defines the chin and whether it is variable amongst extant modern humans. In an attempt to study this problem in a novel way, the current study examines whether the chin is part of a morphologically integrated set of facial and cranial characteristics, as well as whether it is variable in a diverse sample of modern human skeletal remains. </p><p> The morphological integration of the mandible with the cranium has been scrutinized in recent investigations, and results have indicated that some morphological aspects of the mandible covary with the cranium. However, these studies do not evaluate the mentum osseum itself. The chin may be independent of integration with the rest of the skull, indicating that it is a feature that evolved in response to other pressures, such as sexual selection or biomechanical constraints. Conversely, if the mentum osseum is correlated to other measurements of the skull, the appearance of the chin in modern humans may have been a pleiotropic effect of selective forces acting to reduce facial prognathism. </p><p> A diverse modern human sample was analyzed in order to test the degree of correlation and variation found in the mentum osseum. Results indicate that the mentum osseum is not statistically correlated with the majority of measurements from the mandible and cranium and may be independent of any morphological integration. Additionally, the results further demonstrate that the mentum osseum is highly variable in modern human populations.</p>

<p> In organic photovoltaic (OPV) devices, the outer interface structures are crucial in establishing the environment to which charge collection efficiency is keenly sensitive. These outer structures consist of both the physical electrodes and the subsequent electrode contacts formed by integrating electrodes with photoactive materials. Currently, fundamental understanding and strict control of contact effects within OPVs is insufficient. This dissertation is a compilation of this author's research devoted to understanding, modifying, characterizing, and controlling contact effects in OPVs. </p><p> An overview of the role of electrodes and electrode contacts in OPVs is presented in the Introduction (Chapter 1). The following three chapters each embody a fulfilled research project focusing on a specific aspect of the roles and impacts of electrodes and contacts in OPVs. Chapter 2 presents the work of a modeling study on the impacts of electrical surface heterogeneity on OPV performance and establishes guidelines for acceptable degrees of surface electrical heterogeneity. Chapter 3 explores the use of electrochemically deposited and doped conductive polymers as interlayers for OPVs. Chapter 4 utilizes metal-insulator-semiconductor capacitor (MIS-C) structures as a unique platform for isolating the role of electrodes and contacts in facilitating deleterious non-ideal injection and transport pathways in OPVs. The Conclusion (Chapter 5) presents the author's suggestions for future studies involving electrodes and electrode contacts in OPVs.</p>

Abstract Not Available.

A method for the interpretation of irreversible polarographic waves is given. The complex Pb(P2O7)2 has been identified polarographically. The dissociation constant for the complex was found by polarographic and potentiometric studies to be 2 x 10-11. A potentiometric titration study of water solutions of the glasses, sodium hexametaphosphate and sodium quadraphosphate, and of the crystalline forms, sodium pyrophosphate and sodium tripolyphosphate, is given. The precipitate, Pb2P2O7, was observed and the solubility product found to be 1.5 x 10-16. The potentiometric behavior of the quadraphosphate glass in solution was found to be distinctly different from that of a mixture of the same composition but prepared from solutions of sodium pyrophosphate and sodium hexametaphosphate. A close similarity exists between the potentiometric titration curves of the quadraphosphate glass in solution and a mixture of the same composition formed from separate solutions of sodium tripolyphosphate and sodium hexametaphosphate. The potentiometric data indicates the possible existence of the precipitate Pb(Pb2P3O10)2.

Because of suggestions that at least some alum crystals may become ferroelectric at low temperatures, and that a ferroelectric crystal would show anomalies in the absorption of sound, the attenuation of 10, 30 and 50 M.c. sound waves has been measured in alum single crystals over the temperature range of 300&deg;K to 4.2&deg;K. Results are available for both longitudinal and transverse waves propagated in the [111] direction. In the temperature region between 160&deg;K and 70&deg;K we have obtained some very large attenuation peaks. For 10 M.c. these peaks have attained values up to 14 DB/CM, with a normal background attenuation of approximately 1 DB/CM. For the case of 30 M.c. and 50 M.c. the peaks are much higher than for 10 M.c. However, due to the limitations on the electronic equipment our measured values were limited to 14 DB/CM. In AlNH4(SO4)2 &middot; 12H 2O the attenuation peak is in the temperature region where both the real and imaginary parts of the dielectric constant become large, possibly indicating that the crystal is ferroelectric. A calculation, using a simple theory for the attenuation of sound waves in a ferroelectric material, gave results in rough agreement with our measured values. The single crystals used in this experiment were grown here at Rice. The procedure for growing alum single crystals is discussed in the appendix.

Bohmite, gamma-AlOOH, has been found to exist in nature and may be prepared in the laboratory in a variety of ways. From the close similarity of the powder x-radiograms of bohmite and the mineral lepidocrocite, gamma-FeOOH, it has been concluded that the structures are analogous. The existence of the closely related compound gamma-ScOOH has clearly been established by x-ray diffraction and dehydration isobaric studies, but quantitative x-ray studies have not been made. There are two crystalline modifications of the monohydrate of aluminum oxide with the formula AlOOH. The modification corresponding to diaspore, alpha-AlOOH, has been found to be isomorphous with goethite,alpha-FeOOH, of known structure. The second modification corresponding to bohmite, gamma-AlOOH, is isomorphous with lepidocrocite, gamma-FeOOH. The structure of lepidocrocite has been determined by Ewing employing oscillation and rotation photographs of a naturally occurring single crystal. Even though bohmite occurs in nature, it has not been possible to obtain individual crystals suitable for single crystal x-ray studies. Milligan and Weiser, from dehydration isobars of scandium trihydroxide and x-ray diffraction studies, reported the existence of scandium oxide monohydrate, gamma-ScOOH, which they believed to be isomorphous with bohmite. In the present investigation the unit structure, space group symmetry, and detailed atomic arrangement of gamma-AlOOH and gamma-ScOOH have been determined. Since numerous attempts to grow single crystals of both of these monohydrates failed, it was necessary to confine the work done here to powder techniques.

The goal of this research is to observe the variation of the zeta-potential with the concentration and valency of coagulating electrolyte. Using this data, the validity of Verwey and Overbeek's theory will be tested to determine whether or not the stability ratio W is a satisfactory criterion of colloid stability.