Destination Areas (DAs)
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Destination Areas provide faculty and students with new tools to identify and solve complex, 21st-century problems in which Virginia Tech already has significant strengths and can take a global leadership role. The initiative represents the next step in the evolution of the land-grant university to meet economic and societal needs of the world.
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- Gender Inequality and the Division of Household Labor in the United States and Sweden: A Socialist-Feminist ApproachCalasanti, Toni M.; Bailey, Carol A. (University of California Press, 1991-02)In this paper, we offer a socialist-feminist framework for exploring the persistence of gender inequality in the division of household labor. The inconsistent results generated by the relative resources, gender-role ideology, and time-availability hypotheses speak to the need to examine the structural bases for power relations based on gender. Emphasizing the relative autonomy and interrelations of capitalism and patriarchy, socialist-feminism posits that different forms of patriarchal capitalism have varying effects on the division of household labor. (We thus examine the usefulness of this approach by exploring the relationships expressed in three traditional hypotheses about gender inequality and the performance of five household tasks in the United States and Sweden.) The results of our regression analyses indicate that previous perspectives do not adequately examine the power differential embodied in gender relations and that socialist-feminism may give us insights into why gender inequities in the home are maintained despite progressive legislation.
- Public, animal, and environmental health implications of aquacultureGarrett, E. Spencer; dos Santos, Carlos Lima; Jahncke, Michael L. (1997-10)Aquaculture is important to the United States and the world's fishery system. Both import and export markets for aquaculture products will expand and increase as research begins to remove physiologic and other animal husbandry barriers. Overfishing of wild stock will necessitate supplementation and replenishment through aquaculture. The aquaculture industry must have a better understanding of the impact of the ''shrouded'' public and animal health issues: technology ignorance, abuse, and neglect. Cross-pollination and cross-training of public health and aquaculture personnel in the effect of public health, animal health, and environmental health on aquaculture are also needed. Future aquaculture development programs require an integrated Gestalt public health approach to ensure that aquaculture does not cause unacceptable risks to public or environmental health and negate the potential economic and nutritional benefits of aquaculture.
- Campylobacter jejuni - An emerging foodborne pathogenAltekruse, Sean Fitzgerald; Stern, N. J.; Fields, P. I.; Swerdlow, David L. (1999-01)Campylobacter jejuni is the most commonly reported bacterial cause of foodborne infection in the United States. Adding to the human and economic costs are chronic sequelae associated with C. jejuni infection-Guillain-Barre syndrome and reactive arthritis. In addition, an increasing proportion of human infections caused by C. jejuni are resistant to antimicrobial therapy. Mishandling of raw poultry and consumption of undercooked poultry are the major risk factors for human campylobacteriosis. Efforts to prevent human illness are needed throughout each link in the food chain.
- Choosing a Sustainable Future: SANREM CRSP 1999 Annual ReportCason, K. (ed.) (Watkinsville, Ga.: SANREM CRSP, 2000)This document describes the progress of the SANREM CRSP for the period June 1, 1999 to May 31, 2000.
- Dendritic Spikes and Their Influence on Extracellular Calcium SignalingWiest, Michael C.; Eagleman, David M.; King, Richard D.; Montague, P. Read (American Physiological Society, 2000)Extracellular calcium is critical for many neural functions, including neurotransmission, cell adhesion, and neural plasticity. Experiments have shown that normal neural activity is associated with changes in extracellular calcium, which has motivated recent computational work that employs such fluctuations in an information-bearing role. This possibility suggests that a new style of computing is taking place in the mammalian brain in addition to current ‘circuit’ models that use only neurons and connections. Previous computational models of rapid external calcium changes used only rough approximations of calcium channel dynamics to compute the expected calcium decrements in the extracellular space. Using realistic calcium channel models, experimentally measured back-propagating action potentials, and a model of the extracellular space, we computed the fluctuations in external calcium that accrue during neural activity. In this realistic setting, we showed that rapid, significant changes in local external calcium can occur when dendrites are invaded by back-propagating spikes, even in the presence of an extracellular calcium buffer. We further showed how different geometric arrangements of calcium channels or dendrites prolong or amplify these fluctuations. Finally, we computed the influence of experimentally measured synaptic input on peridendritic calcium fluctuations. Remarkably, appropriately timed synaptic input can amplify significantly the decrement in external calcium. The model shows that the extracellular space and the calcium channels that access it provide a medium that naturally integrates coincident spike activity from different dendrites that intersect the same tissue volume.
- From Landscapes to Waterscapes: A PSE for Landuse Change AnalysisRubin, E.J.; Diet, R.; Chanat, J.; Speir, C.; Dymond, Randel L.; Lohani, Vinod K.; Kibler, David F.; Bosch, D. D.; Shaffer, Clifford A.; Ramakrishnan, Naren; Watson, Layne T. (Department of Computer Science, Virginia Polytechnic Institute & State University, 2000)We describe the design and implementation of L2W — a problem solving environment (PSE) for landuse change analysis. L2W organizes and unifies the diverse collection of software typically associated with ecosystem models (hydrological, economic, and biological). It provides a web-based interface for potential watershed managers and other users to explore meaningful alternative land development and management scenarios and view their hydrological, ecological, and economic impacts. A prototype implementation for the Upper Roanoke River Watershed in Southwest Virginia, USA is described.
- An Empirical Analysis of International Confederation of Free Trade Unions (ICFTU) Annual SurveysWeisband, Edward; Colvin, Christopher (Johns Hopkins Univ Press, 2000-02)
- Delayed Medical Care After Diagnosis in a US National Probability Sample of Persons Infected With Human Immunodeficiency VirusTurner, Barbara J.; Cunningham, William E.; Duan, Naihua; Andersen, Ronald M.; Shapiro, Martin F.; Bozzette, Samuel A.; Nakazono, Terry; Morton, Sally C.; Crystal, Steven; St. Clair, Patti; Stein, Michael; Zierler, Sally (AMA, 2000-09-25)Objective: To identify health care and patient factors associated with delayed initial medical care for human immunodeficiency virus (HIV) infection. Design: Survey of a national probability sample of persons with HIV in care. Setting: Medical practices in the contiguous United States. Patients: Cohort A (N = 1540) was diagnosed by February 1993 and was in care within 3 years; cohort B (N = 1960) was diagnosed by February 1995 and was in care within 1 year of diagnosis. Main Outcome Measure: More than 3- or 6-month delay. Results: Delay of more than 3 months occurred for 29% of cohort A (median, 1 year) and 17% of cohort B. Having a usual source of care at diagnosis reduced delay, with adjusted odds ratios (ORs) of 0.61 (95% confidence interval [CI], 0.48-0.77) in cohort A and 0.70 (95% CI, 0.50-0.99) in cohort B. Medicaid coverage at diagnosis showed lower adjusted ORs of delay compared with private insurance (cohort A: adjusted OR, 0.52; 95% CI, 0.30-0.92; cohort B: adjusted OR, 0.48; 95% CI, 0.27-0.85). Compared with whites, Latinos had 53% and 95% higher adjusted ORs of delay (P<.05) in cohorts A and B, respectively, and African Americans had a higher adjusted OR in cohort A (1.56; 95% CI, 1.19-2.04). The health care factors showed similar effects on delay of greater than 6 months. Conclusions: Medicaid insurance and a usual source of care were protective against delay after HIV diagnosis. After full adjustment, delay was still greater for Latinos and, to a lesser extent, African Americans compared with whites.
- Making design work: Sustainability, Product Design and Social EquityWalker, Stuart; Dorsa, Edward A. (Kluwer, 2001)This paper discusses the relationship between the product designer, sustainability and the creation of good quality work within the manufacturing sector. When the principles of sustainability are applied to the nature of employment it points to a new direction for design and product production where ethics, environmental issues and social wellbeing become far more important criteria for ‘success’ than is currently the norm. Awareness of the relationship between ‘work’ and sustainability is not generally being addressed, but needs to become a part of a comprehensive approach to sustainability in design school curricula.
- Sustainable Use of Land and Resources: SANREM CRSP 2000 Annual ReportCason, K. (ed.) (Watkinsville, Ga.: SANREM CRSP, 2001)This document describes the progress of the SANREM CRSP for the period June 1, 2000 through May 31, 2001.
- Testbed Evaluation of Virtual Environment Interaction TechniquesBowman, Douglas A.; Johnson, D.; Hodges, Larry F. (Department of Computer Science, Virginia Polytechnic Institute & State University, 2001)Testbed Evaluation of Virtual Environment Interaction Techniques
- Saving a river: Why do local governments matter?Rola, Agnes C.; Tabien, C. (College, Laguna, Philippines: University of the Philippines Los Baños. School of Environmental Science and Management, 2001)This paper evaluates the sufficiency and local implementation of river management laws in the Philippines. The assessment is that although there are enough policies and regulations, they are not adequately implemented at the local level because the LGUs do not have the necessary ordinances to implement national policies effectively. The authors suggest how market-based instruments to can be developed and implemented to improve river management, using a river in Lantapan, Bukidnon as a case study.
- Using Pinch Gloves(TM) for both Natural and Abstract Interaction Techniques in Virtual EnvironmentsBowman, Douglas A.; Wingrave, Chadwick A.; Campbell, J. B.; Ly, Vinh Q. (Department of Computer Science, Virginia Polytechnic Institute & State University, 2001)Usable three-dimensional (3D) interaction techniques are difficult to design, implement, and evaluate. One reason for this is a poor understanding of the advantages and disadvantages of the wide range of 3D input devices, and of the mapping between input devices and interaction techniques. We present an analysis of Pinch Gloves™ and their use as input devices for virtual environments (VEs). We have developed a number of novel and usable interaction techniques for VEs using the gloves, including a menu system, a technique for text input, and a two-handed navigation technique. User studies have indicated the usability and utility of these techniques.
- Usability Evaluation in Virtual Environments: Classification and Comparison of MethodsBowman, Douglas A.; Gabbard, Joseph L.; Hix, Deborah (Department of Computer Science, Virginia Polytechnic Institute & State University, 2001)Virtual environments (VEs) are a relatively new type of human-computer interface in which users perceive and act in a three-dimensional world. The designers of such systems cannot rely solely on design guidelines for traditional two-dimensional interfaces, so usability evaluation is crucial for VEs. We present an overview of VE usability evaluation. First, we discuss some of the issues that differentiate VE usability evaluation from evaluation of traditional user interfaces such as GUIs. We also present a review of VE evaluation methods currently in use, and discuss a simple classification space for VE usability evaluation methods. This classification space provides a structured means for comparing evaluation methods according to three key characteristics: involvement of representative users, context of evaluation, and types of results produced. To illustrate these concepts, we compare two existing evaluation approaches: testbed evaluation [Bowman, Johnson, & Hodges, 1999], and sequential evaluation [Gabbard, Hix, & Swan, 1999]. We conclude by presenting novel ways to effectively link these two approaches to VE usability evaluation.
- Development of a Collaborative Design Tool for Structural Analysis in an Immersive Virtual EnvironmentSetareh, Mehdi; Bowman, Douglas A.; Tumati, P. (Department of Computer Science, Virginia Polytechnic Institute & State University, 2001)This paper contains the results of an on-going collaborative research effort by the departments of Architecture and Computer Science of Virginia Polytechnic Institute and State University, U.S.A., to develop a computer visualization application for the structural analysis of building structures. The VIRTUAL-SAP computer program is being developed by linking PC-SAP4 (Structural Analysis Program), and virtual environment software developed using the SVE (Simple Virtual Environment) library. VIRTUAL-SAP is intended for use as a collaborative design tool to facilitate the interaction between the architect, engineer, and contractor by providing an environment that they can walk-through and observe the consequences of design alterations. Therefore, this software can be used as an interactive computer-aided analysis of building systems.
- Pinch Keyboard: Natural Text Input for Immersive Virtual EnvironmentsBowman, Douglas A.; Ly, Vinh Q.; Campbell, Joshua M. (Department of Computer Science, Virginia Polytechnic Institute & State University, 2001)Text entry may be needed for system control tasks in immersive virtual environments, but no efficient and usable techniques exist. We present the pinch keyboard interaction technique, which simulates a standard QWERTY keyboard using Pinch Gloves™ and 6 DOF trackers. The system includes visual and auditory feedback and a simple method of calibration.
- Gender Disparity in Third World Technological, Social, and Economic DevelopmentAkubue, Anthony I. (Epsilon Pi Tau and Virginia Tech Libraries, 2001)Despite their seemingly intractable problems, Third World countries have made remarkable progress in improving the well-being of their people in recent decades… A troubling concern, however, is the notion that gains from progress have not been equally beneficial to the genders… This article is about Third World women in relation to technological and socioeconomic progress. It examines the differential gender outcome of this progress and probable causes…
- Testbed evaluation of virtual environment interaction techniquesBowman, Douglas A.; Johnson, D. B.; Hodges, Larry F. (MIT Press, 2001-02-01)As immersive virtual environment (VE) applications become more complex, it is clear that we need a firm understanding of the principles of VE interaction. In particular, designers need guidance in choosing three-dimensional interaction techniques. In this paper, we present a systematic approach, testbed evaluation, for the assessment of interaction techniques for VEs. Testbed evaluation uses formal frameworks and formal experiments with multiple independent and dependent variables to obtain a wide range of performance data for VE interaction techniques. We present two testbed experiments, covering techniques for the common VE tasks of travel and object selection/manipulation. The results of these experiments allow us to form general guidelines for VE interaction and to provide an empirical basis for choosing interaction techniques in VE applications. Evaluation of a real-world VE system based on the testbed results indicates that this approach can produce substantial improvements in usability.
- Expenditures for the Care of HIV-Infected Patients in the Era of Highly Active Antiretroviral TherapyBozzette, Samuel A.; Joyce, Geoffrey; McCaffrey, Daniel F.; Leibowitz, Arleen A.; Morton, Sally C.; Berry, Sandra H.; Rastegar, Afshin; Timberlake, David; Shapiro, Martin F.; Goldman, Dana P. (NEJM Group, 2001-03-15)Background: The introduction of expensive but very effective antiviral medications has led to questions about the effects on the total use of resources for the care of patients with human immunodeficiency virus (HIV) infection. We examined expenditures for the care of HIV-infected patients since the introduction of highly active antiretroviral therapy. Methods: We interviewed a random sample of 2864 patients who were representative of all American adults receiving care for HIV infection in early 1996, and followed them for up to 36 months. We estimated the average expenditure per patient per month on the basis of self-reported information about care received. Results: The mean expenditure was $1,792 per patient per month at base line, but it declined to $1,359 for survivors in 1997, since the increases in pharmaceutical expenditures were smaller than the reductions in hospital costs. Use of highly active antiretroviral therapy was independently associated with a reduction in expenditures. After adjustments for the interview date, clinical status, and deaths, the estimated annual expenditure declined from $20,300 per patient in 1996 to $18,300 in 1998. Expenditures among subgroups of patients varied by a factor of as much as three. Pharmaceutical costs were lowest and hospital costs highest among underserved groups, including blacks, women, and patients without private insurance. Conclusions: The total cost of care for adults with HIV infection has declined since the introduction of highly active antiretroviral therapy. Expenditures have increased for medications but have declined for other services. However, there are large variations in expenditures across subgroups of patients. (N Engl J Med 2001;344:817-23.)
- LTD Induction in Adult Visual Cortex: Role of Stimulus Timing and InhibitionPerrett, Stephen P.; Dudek, Serena M.; Eagleman, David M.; Montague, P. Read; Friedlander, Michael J. (Society for Neuroscience, 2001-04-01)One Hertz stimulation of afferents for 15 min with constant interstimulus intervals (regular stimulation) can induce longterm depression (LTD) of synaptic strength in the neocortex. However, it is unknown whether natural patterns of lowfrequency afferent spike activity induce LTD. Although neurons in the neocortex can fire at overall rates as low as 1 Hz, the intervals between spikes are irregular. This irregular spike activity (and thus, presumably, irregular activation of the synapses of that neuron onto postsynaptic targets) can be approximated by stimulation with Poisson-distributed interstimulus intervals (Poisson stimulation). Therefore, if low-frequency presynaptic spike activity in the intact neocortex is sufficient to induce a generalized LTD of synaptic transmission, then Poisson stimulation, which mimics this spike activity, should induce LTD in slices. We tested this hypothesis by comparing changes in the strength of synapses onto layer 2/3 pyramidal cells induced by regular and Poisson stimulation in slices from adult visual cortex. We find that regular stimulation induces LTD of excitatory synaptic transmission as assessed by field potentials and intracellular postsynaptic potentials (PSPs) with inhibition absent. However, Poisson stimulation does not induce a net LTD of excitatory synaptic transmission. When the PSP contained an inhibitory component, neither Poisson nor regular stimulation induced LTD. We propose that the short bursts of synaptic activity that occur during a Poisson train have potentiating effects that offset the induction of LTD that is favored with regular stimulation. Thus, natural (i.e., irregular) low-frequency activity in the adult neocortex in vivo should not consistently induce LTD.