Now showing items 2046-2065 of 20330


      SEARS, JAY ALLEN (The University of Arizona., 1982)
      Information system professionals need methods to systematically obtain data about interactive computer systems from the users' perspective. This research was concerned with business modeling systems and measuring the performance of subjects learning fundamental operations of the system through training and actual "hands-on" use. The objective was to develop a methodology to measure and evaluate two specific systems: IFPS and VISICALC; to compare subjects' performance in building simple financial projection models and in using the models to answer questions; and to identify learning difficulties associated with the systems. Subjects were business school students with no previous business modeling system experience. Formal measurement was made of the time taken to complete three planning tasks through use of the system. The model user was also the model builder. Performance in decision making was not investigated. Informal observations were made about difficulties the subjects encountered when learning the system. Subjects received two hours of classroom instruction and approximately one hour of "hands-on" training with a specific system. Then under controlled laboratory conditions, they individually demonstrated their ability to use the system. The type and frequency of errors made was also recorded. Subjects were required to use the system until they had completed all tasks correctly. Subjects using IFPS completed tasks in a shorter time than those using the positional system VISICALC. The research methodology was successful in providing feedback for training and design modifications, and also provided for a successful comparison of differences in learning performance when analyzing the effects of previous experience and type of system. Results showed a wide range of performance by subjects, even though they had similar backgrounds. Results suggest that a keyword system is easier to learn for novice users who are learning the fundamental operations of a business modeling system.
    • Būr Saʿīd/Port Said, 1859-1900: Migration, Urbanization, and Empire in an Egyptian and Mediterranean Port-City

      Clancy-Smith, Julia A.; Carminati, Lucia; Darling, Linda; Fortna, Benjamin; Nasiali, Minayo; Fahmy, Ziad (The University of Arizona., 2018)
      Between the 1850s and the early 1900s, an increasing number of migrants landed on Egypt’s shores. Egypt provided an alternative to stagnant economies, offered political stability, and even granted a system of separate judicial courts for foreigners. Within Egypt itself, more and more people moved from villages to cities, such as the rapidly growing Cairo and Alexandria and the brand-new towns of Port Said and Ismailia, arising from scratch along the works for the Suez Canal. My work builds on the existing historiography on migration and urbanization in the Middle East. Scholars have accounted for migrant communities in their histories of cities in the Maghreb, the Ottoman empire, and in Egypt, paying particular attention to Alexandria and Cairo. The cities founded along the Suez Canal upon the inception of its digging in 1859 have garnered some scholarly attention, but no historical inquiry yet exists of the role of mobile individuals in their history and in Egyptian history writ large. This dissertation traces the social and cultural history of Port Said between 1859, when it was founded as the Suez Canal’s northern harbor, and the onset of the twentieth century. It focuses on the role of migrants in influencing the formation of the Egyptian state. My documentary corpus is comprised of letters, petitions, consular court records, police files, the records of religious institutions, maps, and newspapers from thirty-five archives in Egypt, Malta, Italy, Great Britain, and France. The dissertation explores the every-day life of Port Said’s residents at a time of heightened migratory influx into the city. It demonstrates that the heterogeneous workforce who started moving to the isthmus of Suez in the 1850s opened up that area to commercial exploitation and political control. It also shows that, through their mundane, often contentious, encounters with local, consular, colonial, and Egyptian state authorities, the Egyptian and foreign newcomers who peopled the emerging town shaped norms and laws governing the use of the urban space, security, public hygiene, and morality. I conclude that law-making in modern Egypt was not merely the creation of bureaucrats in Cairo but also the work of transient individuals in an utterly new provincial port-city, one called into being by forces at once local and global. My research thus contributes to the histories of Egypt, of mobility in the Middle East, and of the relationship between capitals and ostensibly “peripheral” cities in times of urban transformations.
    • By Force or Choice: Exploring Contemporary Targeted Trafficking of Native Peoples

      Begay, Manley A. Jr; Petillo, April Dama Jackson; Begay, Manley A. Jr; Joe, Jennie R.; Koss, Mary P.; Williams, Robert A. Jr (The University of Arizona., 2015)
      Targeted U.S. domestic sex trafficking of Native peoples has been documented since the time of Custer (Deer 2010, Smith 2005, Smith 2003). According to a few, geographically specific studies this practice continues today (Juran, et al 2014, Minnesota Indian Women's Sexual Assault Coalition 2011, Pierce and Minnesota Indian Women’s Resource Center 2009). The Trafficking Victims Protection Act of 2000 (TVPA), its subsequent reauthorizations and the Violence Against Women’s Act (VAWA) 2013 reauthorization have encouraged activists in Indian Country, defined broadly, to believe that a change is possible within the system if they continue to raise the issue. But what if that strategy is flawed? Despite increasing awareness, it is clear that the United States policy environment has not yet experienced any significant change since the introduction of anti-trafficking law in 2000—especially for Native America. Using a tribal, feminist, critical race perspective alongside Native Nation (re)Building theory and a grounded, interdisciplinary focus, this study explores prominent public policy perceptions about how widespread the targeted domestic sex trafficking of Native peoples is in the United States. The first of its kind, this study reaches across broad geography and perspectives to locate synergies and ruptures that may also present opportunities for Native self-determination in creating effective Indian Country solutions. It also offers United States public policy suggestions helpful in addressing anti-trafficking legislative inefficiencies beyond Indian Country generally.

      Schaffer, William M.; GUREVITCH, JESSICA. (The University of Arizona., 1982)
      In a warm, dry grassland in southeastern Arizona dominated by C₄ grasses the only C₃ grass found was restricted to dry, exposed ridge crests within the hottest and driest part of the region. This was precisely the opposite of what one would predict from physiological and biogeographic considerations, which would lead one to expect a C₃ grass in this environment to be growing on cooler or moister areas that would mitigate the effects of the inhospitable climate. Cover of C₄ grasses was very low on these ridge crests, and increased downslope with the greater volume of water available to high values on the lower slopes and in washes. It was suggested that this C₃ grass, Stipa neomexicana, had a very high tolerance of water stress, but a very poor tolerance of competition, and was limited to unfavorably dry sites by its competitively superior C₄ neighbors. Most species, regardless of photosynthetic type, could not survive in the harsh ridge crest environment, which therefore offered a refuge from competition. The hypothesis of competitive exclusion was tested by removal experiments conducted at ridge crest, midslope and lower slope positions along the topographic gradient of decreasing Stipa neomexicana and increasing C₄ grass cover. The predictions made under this hypothesis were confirmed. The presence of competitors limited the growth of mature plants, flower production, seedling establishment and seedling survival. The beneficial effects of the removal of competitors increased downslope. Competition depressed estimated finite rates of population increase for Stipa neomexicana. This depression was most severe on the lower slope. It was concluded that increasing competition from C₄ grasses along the topographic gradient was responsible for restricting Stipa neomexicana to the unfavorable ridge-crest sites.
    • The c-function for affine Kac-Moody algebras

      Pickrell, Doug; Dang, Son Xuan, 1964- (The University of Arizona., 1996)
      In this paper, we will first study the Harish-Chandra transform and the c-function for finite type Kac-Moody groups. The Harish-Chandra transform is essentially the Gelfand transform on L¹( K\G/K). From our point of view, the c-function arises as the Fourier transform of the diagonal distribution for Haar measures of K. A brief account of Kac-Moody algebras, especially affine Kac-Moody algebras, is also presented. Then we use a formula of Harish-Chandra for the c-function for finite type Kac-Moody groups to discuss the definition of the c-function for affine Kac-Moody algebras, especially the twisted affine Kac-Moody algebras. It turns out the c-function for an affine Kac-Moody algebra can be written as a product of trigonometric functions over the positive roots of the corresponding finite type Kac-Moody algebra. This finite type Kac-Moody algebra is the Lie algebra of a finite type Kac-Moody group G. Then the c-function can be thought as the Fourier transform of the diagonal distribution for a Haar type measure of G. For the affine Kac-Moody algebra of type A⁽¹⁾₁ , G is SL(2, C) and the measure is (trace(g* g))⁻³. This leads to the question of whether (trace( g* g))⁻ᵐ on SL(n, C) is that measure for the affine Kac-Moody algebra of type A⁽¹⁾(n-1). In the last part, for any positive integer l, the Harish-Chandra transform of (trace(g* g) ⁻⁽⁽ⁿ⁽ⁿ⁻¹⁾⁾/²⁾⁻¹ on SL(n, C) is calculated to check if the Fourier transform of the diagonal distribution for (trace(g* g) ⁻⁽⁽ⁿ⁽ⁿ⁻¹⁾⁾/²⁾⁻¹ is the c-function for the affine Kac-Moody algebra of type A⁽¹⁾(n-1).
    • The C-O-H-S gas system and its applications to terrestrial and extraterrestrial volcanism

      Gerlach, Terrance Melvin, 1941- (The University of Arizona., 1974)
    • The C.A.S.E. Approach (Corroboration, About Me, Science, Explain/Advise): Improving Communication with Vaccine-Hesitant Parents

      Peek, Gloanna; Stevens, Jessica Celeste; Peek, Gloanna; McArthur, Donna B.; Badger, Terry A. (The University of Arizona., 2016)
      OBJECTIVES: The anti-vaccination movement is prevalent in today's media with claims which continue to create feelings of fear and trepidation in the minds of many parents. The C.A.S.E. Approach (Corroboration, About Me, Science, Explain/Advise) is a method ofcommunication to be used in formulating meaningful, rapid responses to parents hesitant to vaccinating their children. This DNP project assessed the effects of a C.A.S.E. Approach learning module on family nurse practitioner (FNP) students' perceived levels of knowledge and self-efficacy regarding vaccination discussion with vaccine hesitant parents (VHPs). METHODS: This DNP project used a pretest-posttest design to measure the effects of the C.A.S.E. Approach training intervention on both knowledge and self-efficacy levels of FNP students. Fourteen students participated in this study. Each took the 20-question pretest C.A.S.E. Approach Questionnaire, then participated in the C.A.S.E. Approach learning module,and finished by repeating the questionnaire as a posttest following the intervention. The questionnaire was designed using four-item Likert questions scored 1 (strongly disagree) to 4(strongly agree), wherein higher scores reflected better understanding and self-efficacy in the C.A.S.E. Approach. Students were recruited via an online classroom format within a nursing course offered at the University of Arizona: Nursing 612, Introduction to Pediatrics. All testing and module information was accessed online and questionnaire responses were stored at, also online. RESULTS: Students' posttest scores following the intervention of the C.A.S.E. Approach learning module were significantly higher than pretest scores. Perceived knowledge (p< 0.001)of the C.A.S.E. Approach increased more significantly than did perceived self-efficacy (p =0.001) of the C.A.S.E. Approach following the module. Mean test scores increased on average 14.29 points in perceived knowledge of the C.A.S.E. Approach following the module, and 7.93 points for perceived self-efficacy following the module. CONCLUSION: Key findings included an observed increase in participating students' perceived knowledge regarding the C.A.S.E. Approach as well as an observed increase inparticipating students' perceived self-efficacy in using the C.A.S.E. Approach. There was strong statistical evidence (p≤0.05) to suggest the learning module increased student knowledge andself-efficacy regarding vaccine discussion.
    • C.P.E. Bach's "Rondos for Connoisseurs and Amateurs"

      Webb, Robin Timothy (The University of Arizona., 1984)
    • Cable-drawn farming system analysis and control development

      Coates, Wayne E.; Siemens, Mark Cornelius, 1965- (The University of Arizona., 1996)
      Four types of cable drawn farming systems, a single engine system, a double engine system, a perimeter system, and a double implement system, were analyzed to determine which was best suited for Arizona. The systems were compared in terms of relative cost, reliability/simplicity and field capacity. Field capacity computation variables were implement width, implement speed, tower travel speed, implement carrier travel speed, and implement rotation time. The analysis showed the single engine system was the least expensive, simplest system with a field capacity identical to that of the double engine system, eight percent lower than the double implement system, and approximately thirteen percent higher than the perimeter system. Based on these results, the single implement system was judged superior to the others. The parameters affecting single implement system performance were then examined to optimize performance. The evaluation yielded a recommendation that the system be designed to have a tower speed of 48 ft/min, and a rotation time of 7.5 seconds. A positioning system for the mobile truss of a cable drawn farming system was also developed and tested. The system used a linear move irrigation system's above ground cable guidance system for steering, a wicket positioning system for stopping the machine at the indexing locations, and a wire-alignment system to control inner tower alignment. The system was tested over a length of 280 ft using a five tower, 575 ft long, linear move irrigation system. It was found that the above ground cable guidance system provided ±0.5 ft steering accuracy, the wicket positioning system controlled the power unit and end tower position within ±0.2 ft of the target destination, and that the wire alignment system controlled inner tower position within ±0.3 ft of the target destination. Statistical analysis of the test results showed the probability of position error being controlled to within ±0.4 ft and ±0.8 ft to be at the 99.7% and 99.99% confidence levels, respectively.
    • The cadaver experience: The effects of self-esteem and denial on existential terror in medical students.

      Chatel, Daniel Mark.; Greenberg, Jeff; Fahey, Shirley; McCloskey, Laura (The University of Arizona., 1992)
      Eighty-four medical students at the University of Arizona were administered measures of self-esteem, medical attitudes, social desirability, purpose in life, satisfaction with life, state and trait anxiety one week before their first cadaver dissecting experience. On the day of the experience, half of the subjects completed these measures again in addition to a death anxiety scale just prior to their first cadaver exposure. The other half completed these measures immediately after their first cadaver exposure. Results found main effects of self-esteem with high self-esteem subjects endorsing higher purpose in life and medical attitudes and lower state anxiety and death anxiety. Time by condition interactions were found for state anxiety and purpose in life, with both significantly higher in subjects assessed following exposure to the cadaver. Finally, a main effect for condition was also seen with regard to fear of death, with those exposed to the cadaver scoring significantly higher. Implications with regard to terror management theory and medical education were discussed. In particular, the results tend to support the notion of self-esteem as a psychological buffer against the existential anxiety resulting from an awareness of mortality. Further, results also suggest that cadaver dissection is a powerful emotional experience for physicians in training, significantly affecting their attitudes and requiring sensitivity of medical educators to the psychological impact of cadaver dissection.

      López, Amanda M.; Beezley, William H.; Barickman, Bert J.; Few, Martha; Gosner, Kevin (The University of Arizona., 2010)
      This dissertation explores burial practices and funeral rituals in Mexico City during the late-nineteenth and early-twentieth centuries. I argue that international shifts in ideas about public health, class, and nationalism were reflected in new spaces and practices for dead bodies. Furthermore, I examine how mass death challenged traditional burial practices. The daily practices involved in managing the disposal and veneration of dead bodies illuminate the social and cultural challenges in building modern cities and the ways in which these projects are adopted or rejected by the citizenry. The first three chapters focus on the modernization of burial practices in the nineteenth century. Burial reform laws in the 1850s led to the foundation of the capital's first large, modern cemetery, the Panteón de Dolores, by the Liberal government in 1879. The cemetery became a microcosm for the clean, modern city, mapping the new social class configuration through the distribution of its graves. Quickly the administrators of the Dolores Cemetery failed to meet ideal due to the realities of daily operation. The cemetery had been imagined as a space that reflected elite ideas of modernity, but it served a capital that was mostly indigent. In response to overcrowding, the technology of cremation, which targeted the poor, created a class division between those who could be buried and those who had to be cremated. Government officials successfully constructed a modern, sterile approach to death and began to wrest away control of the symbolic power of death from the Catholic Church. The last two chapters focus on the temporary breakdown of these practices and the reinterpretation of funeral rituals in the early twentieth century. Instability and high mortality rates during the Revolution of 1910-1920 led to overcrowding in cemeteries and spread the dead beyond the cemetery, including impromptu battlefield cremations. A comparison of three funerals in 1928-1929 shows new ways in which the funeral was used to perform ideas about the nation, family, and masculinity. The Revolution's unmanageable casualty levels and the advent modern, secular funerary practices in the period before the Revolution influenced how the government, military, and civilians handled and memorialized death.

      Stuart, Douglas G.; Rankin, Lucinda Lee; Angevine, Jay B., Jr.; Allen, Ronald E.; Burt, Janis M.; Enoka, Roger M.; Hasan, Ziaul (The University of Arizona., 1987)
      To study the detrimental effects of hypokinesia, many models of reduced muscular activity (i.e., reduced-use), including alterations in the size of the living environment, have been developed. Although significant structural and functional changes have been documented, the effect of reduced-use on muscle fatigability remains unclear. This project was designed to study the effects of cage-size on selected properties of rat hindlimb muscle, with particular emphasis on fatigue. Further, in view of the lack of information on the potential effect of gender, both males and females were studied. The rats were raised in either a small, conventional cage or one approximately 133 times larger. Subsequently, terminal experiments were performed to characterize the contractile properties, fiber-type composition and oxidative potential of two hindlimb muscles of the small- and large-cage-reared rats. The test muscles, soleus and extensor digitorum longus, were selected on the basis of their pronounced differences in function, usage and fiber-type composition. The results suggest that reductions in cage-size can influence the properties of skeletal muscle (specifically, muscle mass, force and fatigability) and that this effect is a function of both gender and interanimal differences. However, due to the large variability exhibited by all three factors, their overall effect will be minimal. An analysis of the response of the test muscles to a 6 min fatigue test revealed three findings. First, both muscles exhibited a wide range of fatigability, an unexpected finding particularly for soleus but in keeping with the multiplicity of factors discussed above. Second, the association observed between whole-muscle force and the electromyogram (e.m.g.) was found to be dependent upon the measure used to quantify the e.m.g., the fiber-type composition of the muscle and its degree of fatigability. And third, a coexistence of twitch potentiation and muscle fatigue was observed which also was dependent upon the fiber-type composition and the extent of fatigue. Finally, a comparison of qualitative and quantitative histochemical analyses revealed broad, overlapping ranges for oxidative enzyme activity for each of the three muscle-fiber types. This suggests that differences in fatigability usually attributed to different fiber types are not due solely to differences in oxidative potential.
    • Calcium Modulation of PARP-mediated Cell Death

      Monks, Terrence J.; Muñoz, Frances M.; Monks, Terrence J.; Lau, Serrine S.; Regan, John W.; Wondrak, Georg; Boitano, Scott (The University of Arizona., 2015)
      Many pathological conditions, including renal disease, are associated with oxidative stress. 2,3,5-tris(Glutathion-S-yl)hydroquinone (TGHQ), a potent nephrotoxic and nephrocarcinogenic metabolite of benzene and hydroquinone, generates reactive oxygen species (ROS), can cause DNA strand breaks, and the subsequent activation of DNA repair proteins, including poly(ADP-ribose) polymerase (PARP)-1. Under robust oxidative damage, PARP-1 is hyper-activated, which causes elevations in intracellular calcium concentrations (iCa²⁺), NAD⁺ and ATP depletion, and ultimately necrotic cell death. The role of Ca²⁺ in PARP-dependent necrotic cell death remains unclear. We therefore sought to determine the relationship between Ca²⁺ and PARP-1 during TGHQ-induced necrotic cell death in human renal proximal tubule epithelial cells (HK-2). Extracellular Ca²⁺ is responsible for coupling PARP-1 activation to increases in iCa²⁺ during TGHQ-induced cell death. Moreover, organelles such as the endoplasmic reticulum and the mitochondria, which contain intracellular Ca²⁺ stores play no role in increases of iCa²⁺. PARP-1 inhibition attenuates increases in iCa²⁺ induced by TGHQ, and treatment with 2-aminoethoxydiphenyl borate (2-APB), a store-operated Ca²⁺ channel (SOC) inhibitor, restored cell viability, levels of NAD⁺, and attenuated PAR protein-ribosylation (PARylation). Concurrent with SOC activation having a direct effect on PARP-1 activity, and PARP-1 inhibition attenuating increases in iCa²⁺, the results suggest that PARP-1 and SOCs are coupled during TGHQ-induced cell death. We also explored the relationship between SOC activation and PARP-1 downstream of PARP-1 activity. Poly(ADP-ribose)glycohydrolase (PARG), which catalyzes the degradation of PARs to yield free ADP-ribose (ADPR), is known to activate SOCs. Interestingly, siRNA knockdown of PARG modestly increased PAR ribosylation, but did not restore cell viability in the presence of TGHQ, indicating that free ADPR is not responsible for SOC activation in HK-2 cells. Overall, our results suggest that PARP-1 and Ca²⁺ are coupled through SOC entry, and that this relationship may involve alternative PAR-mediated signaling that leads to necrotic cell death. To further elucidate the role of PAR polymers in response to TGHQ, we determined the cellular co-localization of PAR by immunofluorescent staining. PAR polymers originally co-localized in the nucleus, and in the cytosol at later time points. Immunoprecipitation with a pADPr antibody and further analysis via mass spectrometry revealed PARylation of many stress-related proteins and Ca²⁺-related proteins upon TGHQ treatment. We therefore speculate that cytosolic PAR may cause downstream signaling, PARylating proteins that activate store-operated Ca²⁺ entry either directly through Ca²⁺-related proteins or PARylation of stress-related proteins. Thus, PARylation of proteins may contribute to increases in iCa²⁺ concentrations, leading to PARP-1-dependent necrotic cell death. Our studies provide new insight into PARP-mediated necrotic cell death. Ca²⁺ is coupled to PARP-1 hyperactivation through SOCs, where iCa²⁺ increases are independent of PARG activity, demonstrating a novel signaling pathway for PARP-dependent necrotic cell death.

      Jones, Douglas Wayne (The University of Arizona., 1979)

      Greenlee, W. M.; RUSSELL, DAVID MARTIN. (The University of Arizona., 1983)
      The goal of this dissertation has been to develop a method that enables one to calculate accurate, rigorous lower bounds to the eigenvalues of the standard nonrelativistic spin-free Hamiltonian for an atom with N electrons. Lower bounds are necessary in order to complement upper bounds obtained from the Hartree-Fock and Rayleigh-Ritz techniques. Without accurate lower bounds, it is impossible to estimate the error of the approximate values of the energies. By combining two heretofore distinct methods and using the symmetry properties of the Hamiltonian, this goal has been achieved. The first of the two methods is the method of intermediate problems. By beginning with an appropriately chosen "base operator" H⁰, one forms a sequence of intermediate Hamiltonians Hᵏ, k = 1,2,..., whose corresponding eigenvalues form a sequence of lower bounds to the eigenvalues of the original Hamiltonian H. Complications which occurred in this method due to the stability of essential spectra under compact perturbations were later surmounted with the use of abstract separation of variables by D. W. Fox. The second technique, the effective field method, provides a lower bound operator to the interelectron repulsion term in H that is of the form of a sum of separable potentials. This latter technique reduces the eigenvalue problem for H⁰ to a sum of single particle operators. With the use of a special potential, the Hulthen potential, one may construct an explicitly solvable base problem from the effective field method, if one uses the method of intermediate problems to calculate lower bounds to non-S states. This base problem is then suitable as a starting point for the method of intermediate problems with the Fox modifications. The eigenvalues of the new base problem are already comparable to the celebrated Thomas-Fermi energies. The final part of the dissertation provides a practical procedure for determining the physically realizable spectra of the intermediate operators. This is accomplished by restricting the Hamiltonian to subspaces of proper physical symmetry so that the resulting lower bounds will be to eigenvalues of physical significance.
    • Calculation of the Resummed Radiation Reaction to Order 1/M Using Heavy Fermion Effective Theory

      Fleming, Sean P.; Hill, Andrew; Rutherfoord, John; Su, Shufang; Gralla, Samuel E.; Meinel, Stefan (The University of Arizona., 2020)
      The Abraham-Lorentz-Dirac equation, which is the widely-accepted expression for the recoil force experienced by a radiating charge (known as the \textit{radiation reaction}), displays strange, unphysical behavior. As such, it has been rife with controversy and confusion for over a century. For most of that time, these issues were treated mostly as curiosities and left to the musings of theoreticians. But the advent of high-intensity pulsed tabletop lasers in recent decades has made the radiation reaction relevant to modern experimental physics, which has led to a resurgence of research into the topic. In this dissertation, we calculate the radiation reaction to order $m^{-1}$ experienced by a charge of mass $m$ in an external electromagnetic field resulting from emission of a single photon. To accomplish this, we use heavy fermion effective theory (HFET), which is an effective field theory of QED, and model the total electromagnetic field as the superposition of a quantized self-field associated with the charge and a classical external field. HFET is a novel approach that greatly simplifies the calculation compared to full QED. The simplified calculations allow us to resum our force expression to all orders in $e A_{\text{cl}}$, where $A_{\text{cl}}$ is the background field; this is a novel result. Wilson lines arise in our expressions as a result of resummation.
    • Calculation of transport properties of liquid metals and their alloys via molecular dynamics

      Deymier, Pierre A.; Cherne, Frank Joseph (The University of Arizona., 2000)
      The advanced casting modeler requires accurate viscosity and diffusivity data of liquid metals and their alloys. The present work discusses the use of equilibrium and non-equilibrium molecular dynamics techniques to obtain such data without having to rely on oversimplified phenomenological expressions or difficult and expensive experiments. Utilizing the embedded atom method (EAM), the viscosities and diffusivities for a series of equilibrium and non-equilibrium molecular dynamics simulations of nickel, aluminum, and nickel-aluminum alloys are presented. A critical comparison between the equilibrium and non-equilibrium methods is presented. Besides the transport properties, structural data for the liquids are also evaluated. EAM does a poor job of describing the transport properties of nickel-aluminum alloys, particularly near the equiatomic concentration. It has been suggested that charge transfer between nickel and aluminum atoms is responsible for the discrepancy between numerical calculations and available experimental data. A modified electronic distribution function has been developed to simulate the charge transfer associated with compound formation. The effects of such a "charge transfer" modification to the embedded atom method are evaluated. The results of these simulations indicate that the embedded atom method combined with molecular dynamics may be used as a method to predict reasonably the transport properties.
    • Calculator Use In Developmental Mathematics in a Community College

      Johnson, Bruce; Turner, Erin; Aguilar, Darla Jean; Johnson, Bruce; Turner, Erin; Griego-Jones, Toni (The University of Arizona., 2008)
      The purpose of this study was to examine instructor and student usage of calculators in basic mathematics and prealgebra courses at a community college. Researcher-created surveys were given to 54 instructors and 198 students. The results showed instructors were fairly evenly divided about policies regarding the use of calculators. The major reason for not allowing calculators was that students needed to develop basic skills, and the major reason for allowing calculators was to concentrate on learning concepts. Students used calculators mainly for computation and seldom reported instructors using calculators in class for any other reason. Students were more likely to see calculators as learning tools than were teachers, who saw calculators mainly as computation machines. The results also indicated that instructors were confused about department calculator policies, and students were confused about classroom calculator use policies.