UH Faculty, Staff, and Student Works
Permanent URI for this collectionhttps://hdl.handle.net/10657/22
The collection gathers research products generated by University of Houston faculty, staff, and students
Browse
Browsing UH Faculty, Staff, and Student Works by Title
Now showing 1 - 20 of 1040
- Results Per Page
- Sort Options
Item 2011-01 DATABook-Houston(Hobby Center for Public Policy, 2/1/2011) Hobby Center for Public Policy, University of HoustonItem 2011-02 DATABook-Houston(2/14/2012) Hobby Center for Public Policy, University of HoustonItem 2011-03 DATABook Houston(2/14/2012) Hobby Center for Public Policy, University of HoustonItem A brief measure of peer affiliation and social acceptance (PASA): Validity in an ethnically diverse sample of early adolescents(Journal of Clinical Child and Adolescent Psychology, 3/10/2014) Dishion, Thomas J.; Kim, Han Joe; Stormshak, Elizabeth A.; O'Neill, MayaObjective Conduct a multiagent–multimethod analysis of the validity of a brief measure of deviant peer affiliations and social acceptance (PASA) in young adolescents. Peer relationships are critical to child and adolescent social and emotional development, but currently available measures are tedious and time consuming. The PASA consists of a youth, parent, and teacher report that can be collected longitudinally to study development and intervention effectiveness. Method This longitudinal study included 998 middle school students and their families. We collected the PASA and peer sociometrics data in Grade 7 and a multiagent–multimethod construct of deviant peer clustering in Grade 8. Results Confirmatory factor analyses of the multiagent–multimethod data revealed that the constructs of deviant peer affiliations and social acceptance and rejection were distinguishable as unique but correlated constructs within the PASA. Convergent, discriminant, concurrent, and predictive validity of the PASA was satisfactory, although the acceptance and rejection constructs were highly correlated and showed similar patterns of concurrent validity. Factor invariance was established for mother and for father reports. Conclusions Results suggest that the PASA is a valid and reliable measure of peer affiliation and of social acceptance among peers during the middle school years and provides a comprehensive yet brief assessment of peer affiliations and social acceptance.Item A Case for Competencies: Assessing the Value of Trait-Based Performance Appraisal for Non-Faculty University Employees(Educational Policy Analysis Archives, 5/11/2016) Messa, Emily A; Horn, Catherine L.; Longacre, Teri Elkins; Olenchak, F. Richard; Penney, Lisa M.A case study analyzed how supervisors at one university selected competencies, or trait-based skills, for non-faculty employees. This case study provides a valuable contribution by focusing on employees at one institution type–a large, public research university. While it has been documented that non-faculty employees provide important contributions to higher education, there is more to be discovered about this population of university employee, noted as more than 2 million U.S. employees in 2011. The research question guiding this study was: Within a university setting, how are employee competencies valued by job title within colleges and divisions? Multiple correspondence analysis evaluated supervisor competency selection for 1,836 non-supervisory and 565 supervisory employees using data from this university’s 2012 performance appraisal. For non-supervisory employees, the first dimension accounted for 65.11% of adjusted inertia, or explained variance. The second dimension accounted for 23.89% of adjusted inertia. For supervisory employees, the first dimension accounted for 86.57% of adjusted inertia. The second dimension accounted for 8.26% of adjusted inertia. The key study finding was that, despite the availability of other higher-education specific competency alternatives and best practices for competency use in the appraisal, this institution’s implementation of competencies was found to be mechanical. This study proposed best practices for this and similarly situated institutions as to how competencies can be used to develop employees and improve their performance.Item A Computational Mapping of Online News Deserts on African News Websites(2023-09-28) Madrid-Morales, Dani; Rodríguez-Amat, Joan Ramon; Lindner, PeggyTo date, the study of news deserts, geographic spaces lacking local news and information, has largely focused on countries in the Global North, particularly the United States, and has predominantly been interested in the causes and consequences of the disappearance of local media outlets (e.g., newspapers and TV stations) to the social fabric of a community. In this article, we extend the concept of “news deserts” by drawing on literature on the geography of news in Africa, where information voids have long been documented but have not been studied within the conceptual framework of news deserts. Using computational tools, we analyse a sample of 519,004 news articles published in English or French by news websites in 39 African countries. We offer evidence of the existence of online news deserts at two levels: at a continental level (i.e., some countries/regions are hardly ever covered by online media of other African countries) and at a domestic level (i.e., online news media of a given country seldom cover large areas of the said country). This article contributes to the study of news deserts by (a) examining a continent that has not been featured in previous research, (b) testing a methodological approach that employs computational tools to study news geographies online, and (c) exploring the flexibility of the term and its applicability to different media ecosystems.Item A Cooperative Bayesian Nonparametric Framework for Primary User Activity Monitoring in Cognitive Radio Networks(IEEE Journal on Selected Areas in Communications, 2/2/2012) Saad, Walid; Han, Zhu; Poor, H. Vincent; Ba?ar, Tamer; Song, Jin BinThis paper introduces a novel approach that enables a number of cognitive radio devices that are observing the availability pattern of a number of primary users (PUs), to cooperate and use Bayesian nonparametric techniques to estimate the distributions of the PUs' activity pattern. To address this problem, a coalitional game is formulated between the cognitive devices and an algorithm for cooperative coalition formation is proposed. It is shown that the proposed coalition formation algorithm allows the cognitive nodes that are experiencing a similar behavior from some PUs to self-organize into disjoint, independent coalitions. Inside each coalition, the cooperative cognitive nodes use Bayesian nonparametric techniques so as to improve the accuracy of the estimated PUs' activity distributions. Simulation results show that the proposed algorithm significantly improves the estimates of the PUs' activity patterns.Item A Critical Look at Partial Least Squares Modeling(MIS Quarterly, 2009-03) Marcoulides, George A.; Chin, Wynne W.; Saunders, CarolN/AItem A Field Study of the Antecedents and Performance Consequences of Perceived Accountability(Journal of Management, 9/1/2014) Mero, Neal P.; Guidice, Rebecca M.; Werner, SteveBuilding on theoretical and empirical work considering the implications of accountability on individual behavior, the authors explored the antecedents and consequences of individual perceptions of accountability for job performance. Using data from two field samples, the authors considered whether the manager’s monitoring behavior thought to enhance perceptions of accountability for behaviors and outcomes predicted greater perceived accountability for task performance and interpersonal facilitation performance. They also explored whether perceived accountability mediated the relationship between monitoring behavior and subsequent performance. Hierarchical linear modeling indicated that subordinates of managers whose monitoring behavior reinforced perceptions of accountability perceived greater accountability for performance and that this perception mediated the relationship between managerial monitoring behavior and performance. The implications of these results and directions for future research are discussed.Item A fully resolved numerical simulation of turbulent flow past one or several spherical particles(The Physics of Fluids, 1/31/2012) Botto, L.; Prosperetti, AndreaThe flow past one or nine spheres arranged in a plane lattice held fixed in a stream of decaying homogeneous isotropic turbulence is studied by means of fully resolved Navier-Stokes simulations. The particle radius is 3–5 times the Kolmogorov length and about 1/3 of the integral length scale. The mean particle Reynolds number is 80 and the turbulence intensity 17% and 33%. Several features of the flow are described: the mean and fluctuating dissipation and its spatial distribution, the mean and fluctuating hydrodynamic forces on the spheres, stimulated vortex shedding, and others. A special attention is paid to the relation between the work done on the fluid by the particles (in the reference frame of the former) and the total dissipation. It is shown that these quantities, which are assumed to balance in many point-particle models, can actually be very different when inertial effects are important.Item A Game-Theoretic Approach to Energy Trading in the Smart Grid(IEEE Transactions on Smart Grid, 4/15/2014) Wang, Yunpeng; Saad, Walid; Han, Zhu; Poor, H. Vincent; Ba?ar, TamerElectric storage units constitute a key element in the emerging smart grid system. In this paper, the interactions and energy trading decisions of a number of geographically distributed storage units are studied using a novel framework based on game theory. In particular, a noncooperative game is formulated between storage units, such as plug-in hybrid electric vehicles, or an array of batteries that are trading their stored energy. Here, each storage unit's owner can decide on the maximum amount of energy to sell in a local market so as to maximize a utility that reflects the tradeoff between the revenues from energy trading and the accompanying costs. Then in this energy exchange market between the storage units and the smart grid elements, the price at which energy is traded is determined via an auction mechanism. The game is shown to admit at least one Nash equilibrium and a novel algorithm that is guaranteed to reach such an equilibrium point is proposed. Simulation results show that the proposed approach yields significant performance improvements, in terms of the average utility per storage unit, reaching up to 130.2% compared to a conventional greedy approach.Item A general derivation of the subharmonic threshold for non-linear bubble oscillations(The Journal of the Acoustical Society of America, 6/5/2013) Prosperetti, AndreaThe paper describes an approximate but rather general derivation of the acoustic threshold for a subharmonic component to be possible in the sound scattered by an insonified gas bubble. The general result is illustrated with several specific models for the mechanical behavior of the surface coating of bubbles used as acoustic contrast agents. The approximate results are found to be in satisfactory agreement with fully non-linear numerical results in the literature. The amplitude of the first harmonic is also found by the same method. A fundamental feature identified by the analysis is that the subharmonic threshold can be considerably lowered with respect to that of an uncoated free bubble if the mechanical response of the coating varies rapidly in the neighborhood of certain specific values of the bubble radius, e.g., because of buckling.Item A Generalization of the Rayleigh-Plesset Equation of Bubble Dynamics(The Physics of Fluids, 1982-03) Prosperetti, AndreaThe classical Rayleigh?Plesset equation of spherical bubble dynamics in an incompressible liquid is generalized to include the non?Newtonian behavior of the liquid and mass exchange processes at the bubble interface.Item A Heterogeneous Robotics Team for Large-Scale Seismic Sensing(IEEE Robotics and Automation Letters, 2/8/2017) Sudarshan, Srikanth K. V.; Montano, Victor; Nguyen, An; McClimans, Michael; Chang, Li; Stewart, Robert R.; Becker, Aaron T.Seismic surveying requires placing a large number of sensors (geophones) in a grid pattern, triggering a seismic event, and recording vibration readings. The goal of the surveying is often to locate subsurface resources. Traditional seismic surveying employs human laborers for sensor placement and retrieval. The major drawbacks of surveying with human deployment are the high costs and time, and risks to humans due to explosives, terrain, and climatic conditions. We propose an autonomous, heterogeneous sensor deployment system using unmanned aerial vehicles to deploy mobile and immobile sensors. The proposed system begins to overcome some of the problems associated with traditional systems. This paper provides detailed analysis and comparison with traditional survey techniques. Hardware experiments and simulations show promise for automation reducing cost and time. Autonomous aerial systems will have a substantial contribution to make in future seismic surveys.Item A Hierarchical Game With Strategy Evolution for Mobile Sponsored Content and Service Markets(IEEE Transactions on Communications, 9/24/2018) Wang, Wenbo; Xiong, Zehui; Niyato, Dusit; Wang, Ping; Han, ZhuIn sponsored content and service markets, the content and service providers are able to subsidize their target mobile users through directly paying the mobile network operator to lower the price of the data/service access charged by the network operator to the mobile users. The sponsoring mechanism leads to a surge in mobile data and service demand, which in return compensates for the sponsoring cost and benefits the content/service providers. In this paper, we study the interactions among the three parties in the market, namely, the mobile users, the content/service providers, and the network operator, as a two-level game with multiple Stackelberg (i.e., leader) players. Our study is featured by the consideration of global network effects owning to consumers' grouping. Since the mobile users may have bounded rationality, we model the service-selection process among them as an evolutionary-population follower sub-game. Meanwhile, we model the pricing-then-sponsoring process between the content/service providers and the network operator as a non-cooperative equilibrium searching problem. By investigating the structure of the proposed game, we reveal a few important properties regarding the equilibrium existence and propose a distributed, projection-based algorithm for iterative equilibrium searching. Simulation results validate the convergence of the proposed algorithm and demonstrate how sponsoring helps improve both the providers' profits and the users' experience.Item A high-throughput microfluidic approach for 1000-fold leukocyte reduction of platelet-rich plasma(Scientific Reports, 10/24/2016) Xia, Hui; Strachan, Briony C.; Gifford, Sean C.; Shevkoplyas, Sergey S.Leukocyte reduction of donated blood products substantially reduces the risk of a number of transfusion-related complications. Current ‘leukoreduction’ filters operate by trapping leukocytes within specialized filtration material, while allowing desired blood components to pass through. However, the continuous release of inflammatory cytokines from the retained leukocytes, as well as the potential for platelet activation and clogging, are significant drawbacks of conventional ‘dead end’ filtration. To address these limitations, here we demonstrate our newly-developed ‘controlled incremental filtration’ (CIF) approach to perform high-throughput microfluidic removal of leukocytes from platelet-rich plasma (PRP) in a continuous flow regime. Leukocytes are separated from platelets within the PRP by progressively syphoning clarified PRP away from the concentrated leukocyte flowstream. Filtrate PRP collected from an optimally-designed CIF device typically showed a ~1000-fold (i.e. 99.9%) reduction in leukocyte concentration, while recovering >80% of the original platelets, at volumetric throughputs of ~1?mL/min. These results suggest that the CIF approach will enable users in many fields to now apply the advantages of microfluidic devices to particle separation, even for applications requiring macroscale flowrates.Item A high-throughput screen to identify inhibitors of SOD1 transcription(Frontiers in Bioscience, 2014-07) Wright, Paul D.; Wightman, Nicholas; Huang, Mickey M.; Weiss, Alexandra; Sapp, Peter C.; Cuny, Gregory D.; Ivinson, Adrian J.; Glicksman, Marcie A.; Ferante, Robert J.; Matson, Wayne; Matson, Samantha; Brown, Robert H. Jr.Amyotrophic lateral sclerosis (ALS) is a fatal degenerative motor neuron disease. Approximately 20% of familial ALS cases are caused by mutations in the Cu/Zn superoxide dismutase (SOD1) gene. Rodents expressing mutant SOD1 transgenes develop progressive, fatal motor neuron disease and disease onset and progression is dependent on the level of SOD1. We investigated the possibility that a reduction in SOD1 protein may be of therapeutic benefit in ALS and screened 30,000 compounds for inhibition of SOD1 transcription. The most effective inhibitor identified was N-{4-[4-(4-methylbenzoyl)-1-piperazinyl]phenyl}-2-thiophenecarboxamide (Compound ID 7687685), which in PC12 cells showed an EC50 of 10.6 microM for inhibition of SOD1 expression and an LD50 >30 microM. This compound was subsequently shown to reduce endogenous SOD1 levels in HeLa cells and to exhibit a modest reduction of SOD1 protein levels in mouse spinal cord tissue. These data suggest that the efficacy of compound 7687685 as an inhibitor of SOD1 gene expression is not likely to be clinically useful, although the strategy reported could be applied broadly to screening for small molecule inhibitors of gene expression.Item A high-throughput single-cell analysis of human CD8+ T cell functions reveals discordance for cytokine secretion and cytolysis(Journal of Clinical Investigation, 2011-10) Varadarajan, Navin; Julg, Boris; Yamanaka, Yvonne J.; Chen, Huabiao; Ogunniyi, Adebola O.; McAndrew, Elizabeth; Porter, Lindsay C.; Piechocka-Trocha, Alicja; Hill, Brenna J.; Douek, Daniel C.; Pereya, Florencia; Walker, Bruce D.; Love, Christopher J.CD8+ T cells are a key component of the adaptive immune response to viral infection. An inadequate CD8+ T cell response is thought to be partly responsible for the persistent chronic infection that arises following infection with HIV. It is therefore critical to identify ways to define what constitutes an adequate or inadequate response. IFN-? production has been used as a measure of T cell function, but the relationship between cytokine production and the ability of a cell to lyse virus-infected cells is not clear. Moreover, the ability to assess multiple CD8+ T cell functions with single-cell resolution using freshly isolated blood samples, and subsequently to recover these cells for further functional analyses, has not been achieved. As described here, to address this need, we have developed a high-throughput, automated assay in 125-pl microwells to simultaneously evaluate the ability of thousands of individual CD8+ T cells from HIV-infected patients to mediate lysis and to produce cytokines. This concurrent, direct analysis enabled us to investigate the correlation between immediate cytotoxic activity and short-term cytokine secretion. The majority of in vivo primed, circulating HIV-specific CD8+ T cells were discordant for cytolysis and cytokine secretion, notably IFN-?, when encountering cognate antigen presented on defined numbers of cells. Our approach should facilitate determination of signatures of functional variance among individual effector CD8+ T cells, including those from mucosal samples and those induced by vaccines.Item A Latent Class Analysis of Personal Values in Young Adults(Collabra: Psychology, 2017-12) Smack, Avante J.; Tackett, Jennifer L.; Walker, Rheeda L.; Tang, Rui; Herzhoff, KathrinHuman values and motivations are a powerful predictor of behavior, and Schwartz's taxonomy offers a meaningful organizational system for robust value dimensions (Schwartz, 1992). Although values clearly represent a meaningful and culturally relevant dimension of individual differences, they remain poorly understood particularly in regards to how values co-occur and manifest within individuals. The purpose of the present study was to examine how values co-occur and manifest within individuals. A racially/ethnically diverse sample of 1, 308 undergraduate students (351 males, Mage = 21.70, SD = 5.22) reported on their personal values and personality traits. Latent class analyses revealed support for two value classes: personal-focused (N = 210) and social-focused (N = 1098), which map onto hypotheses of value configurations based on Schwartz's taxonomy (Schwartz, 1992). The value classes also exhibited differences based on racial/ethnic composition, gender composition, and personality trait association, also consistent with previous research. The current study provides evidence for two value types that manifest across two countries in North America.Item A longitudinal examination of the associations between shyness, drinking motives, alcohol use, and alcohol-related problems(Alcoholism: Clinical, and Experimental Research, 2015-09) Young, Chelsie M.; DiBello, Angelo M.; Traylor, Zachary K.; Zvolensky, Michael J.; Neighbors, ClaytonBackground: The current study evaluated the roles of drinking motives and shyness in predicting problem alcohol use over two years. Methods: First-year college student drinkers (N=818) completed assessments of alcohol use and related problems, shyness, and drinking motives every six months over a two year period. Results: Generalized linear mixed models indicated that shyness was associated with less drinking, but more alcohol-related problems. Further, shyness was associated with coping, conformity, and enhancement drinking motives, but was not associated with social drinking motives. However, when examining coping motives, moderation analyses revealed that social drinking motives were more strongly associated with coping motives among individuals higher in shyness. In addition, coping, conformity, and enhancement motives, but not social motives, mediated associations between shyness and alcohol-related problems over time. Finally, coping motives mediated the association between the interaction of shyness and social motives and alcohol-related problems. Conclusions: Together, the results suggest that shy individuals may drink to reduce negative affect, increase positive affect, and fit in with others in social situations, which may then contribute to greater risk for subsequent alcohol-related problems.