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The standards and regulations for the proposed Yucca Mountain high level radioactive waste repository, which were developed and promulgated by the U.S. Environmental Protection Agency and the U.S. Nuclear Regulatory Commission, respectively, are complex and challenging. A major reason is that they are divided into three parts, an Individual Protection Standard, a Human Intrusion Standard, and multiple Ground Water Protection Standards. Because the individual parts are not fully integrated, the one that controls under a specific set of circumstances depends on the radionuclide being evaluated, its mechanisms of transport, its avenues of intake, and differences in the specified limits. Although the coefficients in Federal Guidance Report (FGR) No. 11 are being used to estimate the doses, other sources (for example, Title 10, CFR, Part 20, and/or FGR No. 13) may deserve consideration. Since the regulations specify that the reasonably maximally exposed individual is an adult, this leaves unanswered the estimated doses to other age groups, such as infants and adolescents. Summarized in this paper are comparisons of the dose coefficients for different age groups, as well as evaluations of the sensitivity of effective and organ dose estimates for adults, depending on the source of the coefficients. All the latter analyses were based only on the consumption of ground water. While the dose estimates are different, depending on the sources of the coefficients, this was not unexpected. What these evaluations demonstrate is the caution that must be exercised to ensure that a full range of considerations is taken into account in interpreting the outcome of the dose assessments being made with respect to the proposed repository. [ABSTRACT FROM AUTHOR]

A direct mail oiler, common to the casino industry, is analyzed using performance data obtained from the player database of a Las Vegas Strip hotel casino. These free-play offers, fueled by technological advances in player tracking systems, attempt to encourage repeat patronage by offering cash awards and free room nights. Despite compulsory play requirements, these popular oilers fail to generate a statistically significant increase in individual trip slot volume. This result held across two levels of the offer, i.e., both $50 and $100 cash offers. Once offer costs are considered, the free-play campaign is found to produce negative cash flows. Related long-term issues, such as the inducement of increased visitation and polygamous loyalty, are also addressed. These unique results enrich both the casino marketing and direct marketing literature bases. Most importantly, this paper represents the only empirical study of a popular play incentive, increasing its practical value to casino operators. [ABSTRACT FROM AUTHOR]

Abstract: Xu et al. (2003) [Xu, T., Sonnenthal, E., Bodvarsson, G., 2003. A reaction-transport model for calcite precipitation and evaluation of infiltration–percolation fluxes in unsaturated fractured rock. J. Contam. Hydrol., 64, 113–127.] presented results of a reaction-transport model for calcite deposition in the unsaturated zone at Yucca Mountain, and compared the model results to measured abundances in core from a surface-based borehole. Marshall et al. (2003) [Marshall, B.D., Neymark, L.A., Peterman, Z.E., 2003. Estimation of past seepage volumes from calcite distribution in the Topopah Spring Tuff, Yucca Mountain, Nevada. J. Contam. Hydrol., 62–63, 237–247.] used the calcite distribution in the Topopah Spring Tuff to estimate past seepage into lithophysal cavities as an analog for seepage into the potential repository waste emplacement drifts at Yucca Mountain in southern Nevada (USA). Dublyansky and Smirnov (2005) [Dublyansky, Y.V., Smirnov, S.Z., 2005. Commentary: assessment of past infiltration fluxes through Yucca mountain on the basis of the secondary mineral record—is it a viable methodology? J. Contam. Hydrol. (this issue).] wrote a commentary paper to Marshall et al. (2003) [Marshall, B.D., Neymark, L.A., Peterman, Z.E., 2003. Estimation of past seepage volumes from calcite distribution in the Topopah Spring Tuff, Yucca Mountain, Nevada. J. Contam. Hydrol., 62–63, 237–247.] and Xu et al. (2003) [Xu, T., Sonnenthal, E., Bodvarsson, G., 2003. A reaction-transport model for calcite precipitation and evaluation of infiltration–percolation fluxes in unsaturated fractured rock. J. Contam. Hydrol., 64, 113–127.], containing two points: (1) questionable phenomenological model for the secondary mineral deposits and (2) inappropriate thermal boundary conditions. In this reply we address primarily the modeling approach by showing results of a sensitivity simulation regarding the effect of an elevated temperature history that approximates the temperature history inferred from fluid inclusions by Wilson et al. (2003) [Wilson, N.S.F., Cline, J.S., Amelin, Y.V., 2003. Origin, timing, and temperature of secondary calcite–silica mineral formation at Yucca Mountain, Nevada. Geochimica et Cosmochimica Acta, 67 (6), 1145–1184.]. Modeled calcite abundances using the time-varying temperature history are similar to the results for the steady-state ambient temperature profile (Xu, T., Sonnenthal, E., Bodvarsson, G., 2003. A reaction-transport model for calcite precipitation and evaluation of infiltration–percolation fluxes in unsaturated fractured rock. J. Contam. Hydrol., 64, 113–127), and are still consistent with the measured abundances at the proposed repository horizon. [Copyright &y& Elsevier]

Abstract: Two papers recently published in the Journal of Contaminant Hydrology by Marshall et al. [Marshall, B.D., Neymark, L.A., Peterman, Z.E., 2003. Estimation of past seepage volumes from calcite distribution in the Topopah Spring Tuff, Yucca Mountain, Nevada. J. Contam. Hydrol. 62–63, 237–247] and Xu et al. [Xu, T., Sonnenthal, E., Bodvarsson, G., 2003. A reaction–transport model for calcite precipitation and evaluation of infiltration fluxes in unsaturated fractured rock. J. Contam. Hydrol. 64, 113–127] attempt to assess past volumes of seepage and infiltration fluxes through the vadose zone of Yucca Mountain, Nevada, on the basis of the modeling of the spatial distribution of secondary calcite. In this commentary, we argue that the employed methodology is not viable. In addition, the thermal boundary conditions used in simulations do not correspond to the temperatures of the mineral forming fluids established on the basis of the fluid inclusion studies. [Copyright &y& Elsevier]

Abstract: The use of cosmogenic nuclide dating methods place in doubt the long-term future of weathering rinds (WRs) as a chronometric tool. Why estimate ages when radiometric control is possible? This paper presents evidence that WRs can provide invaluable clues about what particular sample would provide the most accurate cosmogenic age by avoiding “inheritance” of cosmogenic nuclides and by avoiding boulders undergoing spalling. The key to this new use requires testing the occurrence and nature of WR erosion. Back-scattered electron microscopy reveals that ignimbrite, andesite, basalt, and granitic clasts experience WR erosion in all subsurface and surface contexts thus far studied in Arizona, California, Hawaii, Oregon, and Washington. To understand the magnitude of WR erosion, we measured WR thicknesses, all while controlling the cosmogenic and surface stability ages of clasts by chlorine-36 and rock varnish microlamination dating methods. Our data reveal that traditional methodologies of sampling cobbles remove two-thirds of the true thickness of weathering rinds, calling into question many beliefs including the notion that clay minerals are not produced during weathering-rind formation. Comparisons of optical and electron microscope measurements support concerns that measurement of WRs by color changes, while useful as a pedagogical tool, creates serious biases in underestimating the true dynamics of WRs. In the end, we found that concordance of WR and rock coating “age trends” indicates the ideal boulder for cosmogenic nuclide dating. Offsets reveal either ongoing boulder erosion, invalidating “zero erosion” model ages, or a potential problem with “inheritance” of cosmogenic nuclides. [Copyright &y& Elsevier]

Change vector analysis (CVA) partitions spectral change into magnitude and direction components. Although recognized as an effective change detection method, CVA has two limitations. First, it is usually applied to only two bands, and secondly, the selection of a threshold for the magnitude of change can be difficult. These limitations have been addressed through recent research. Hyperspherical direction cosine (HSDC) CVA is an extension of conventional two-band CVA to many dimensions. Training areas can be used to guide the selection of the change magnitude threshold for discriminating Change and No Change classes. This paper provides a discussion on previous uses of HSDC approaches, and develops a simple procedure for selecting the change magnitude threshold automatically. The application of HSDC CVA and conventional CVA to a Landsat multiSpectral scanner (MSS) Las Vegas, Nevada, dataset is used to demonstrate the application of the approach, and quantify the accuracy gained by incorporating multiple bands in the change analysis. Conventional CVA resulted in an overall accuracy of 69% (Kappa?=?0.60), compared to 74% for HSDC CVA (Kappa?=?0.68). [ABSTRACT FROM AUTHOR]

Private communities, many of them gated, are the predominant form of new housing construction across much of the United States. The rapid spread of this institution is driven by structural forces such as rising land costs, local government fiscal constraints, and consumer preferences for security and control over space. Some municipalities, such as Las Vegas, are actively promoting this transformation of home ownership and governance. New housing developments must be governed by private homeowner associations and existing neighbourhoods are under pressure to become private communities. This paper presents the case study of Bonanza Village, an old Las Vegas neighbourhood that was turned into a gated community, over the objections of many of its residents, through concerted action of a neighbourhood homeowner association and the City of Las Vegas. [ABSTRACT FROM AUTHOR]

This paper measures the effect of health risk on housing values by exploiting a natural experiment that mitigates both econometric problems. The analysis focuses on Churchill, an isolated county in Nevada where residents have recently experienced a severe increase in pediatric leukemia. Housing prices are compared before and after the increase with a nearby county acting as a control group. The variation in health risk over time makes it possible to control for unobserved differences across locations. In addition, because the leukemia cases were unanticipated there is no reason to expect sorting of households according to preferences prior to the increase. Finally, because many houses were sold repeatedly during the sample period it is possible to control for unobserved property-specific heterogeneity. Housing prices in the affected county closely followed trends in housing prices for the control county and the rest of the state of Nevada during the period leading up to the leukemia increase. Then, beginning when eight children were diagnosed in 2000, housing prices in the affected county decline significantly. Least-squares estimates indicate that houses sold during the period of maximum risk sold for 15.6 percent less than equivalent houses not affected by the leukemia increase.

Much of the academic literature dealing with state and local demography involves the development and evaluation of methods for estimating population. The focus on estimation methods is not surprising because they are used in many states to allocate resources. The quality control in regard to the validity and reliability afforded these methods by the traditional academic peer review process is important because, among other things, it serves to reduce the high potential for conflict that exists when resources are at stake. There are, however, methods being used by state and local demographers that have not been subject to peer review. While not necessarily un- sound, these "fugitive" methods serve to keep the potential for conflict high because of the uncertainty regarding their validity and reliability. This paper examines just such a situation in the form of a case study. It is a discussion of a regression model developed in Nevada following the 2000 census that led to conflict over its use to estimate the population of Clark County, Nevada in 2002. The discussion reveals statistical and methodological shortcomings in this model that lead to an alternative model not subject to these shortcomings. This example illustrates how this type of analysis and discussion can lead to a wider understanding of methods on the part of practitioners through the corrective process of academic peer review. It also suggests that states in which estimates are used to allocate resources would be well-served by subjecting new methods being considered for use to academic peer review before they are adopted. [ABSTRACT FROM AUTHOR]

Local gamblers are an important market segment for casino marketers providing a reliable source of revenue during slow periods. This paper presents selected gaming behavior of local residents in the Las Vegas area, linking socio-demographic characteristics with gaming behavior. In addition, this article examines the relationships of Las Vegas area locals and their visiting friends and family members in two aspects. First, we identified the influence local residents have on visiting friends and family in terms of recommendations made regarding gambling in general and specific gaming locations. Second, this article describes how visiting friends and family influence local residents in terms of gaming behavior and additional spending. [ABSTRACT FROM AUTHOR]

As part of the site characterization efforts at Yucca Mountain, Nevada, a series of unsaturated zone tracer tests has been performed at nearby Busted Butte. The phase 2 tracer test was conducted within an instrumented 10 m by 10 m by 7 m in situ block of vitric tuff. A complex tracer solution containing both reactive and nonreactive tracers was pumped into the block during a period of 27 months. Throughout the test, thousands of unsaturated zone pore water samples were collected on sorptive pads attached to inverting membranes and then analyzed for tracer concentration. Partway through the experiment, three new boreholes were drilled into the block, and two intercepted the tracer plume. The rock core was removed for pore water extraction and analysis, and the boreholes were then instrumented with inverting membranes and sorptive pads. The initial set of pore water-soaked pads was removed from the boreholes a week after they were emplaced, and the pore water was extracted and analyzed. This paper compares the tracer concentration data from the rock cores and the pads to evaluate the effectiveness of the inverting membrane collection technique for a variety of tracers. While the sorptive pads sample only dissolved tracers, rock cores contain both dissolved and sorbed tracer. For nonreactive tracers, such as halides (bromide and iodide) and fluorinated benzoic acids (FBAs), this distinction is immaterial, and the rock and pad data agree quantitatively for the halide tracers, and qualitatively for the FBAs. For reactive tracers, such as lithium, the dissolved tracer concentrations can be estimated from rock analyses by dividing by the tracer's retardation factor; when this correction is applied, the rock and pad lithium data are also in reasonable agreement. [ABSTRACT FROM AUTHOR]

Three late Paleozoic, angular unconformities, each tightly constrained in age by biostratigraphy, are exposed in Carlin Canyon, Nevada. These record deformation as well as erosion. Folding associated with these deformation events is roughly coaxial; all three sets of fold axes trend northeast. Each unconformity represents tectonic disruption of the middle part of the western North American margin between the times of the initiation of the Antler orogeny (Late Devonian—Early Mississippian) and the Permian—Triassic Sonoma orogeny. This paper focuses on one of these unconformities in the Middle Pennsylvanian—the C6 unconformity—and the deformation and age constraints associated with it. Our data from Carlin Canyon yield detailed glimpses of how the Antler foreland evolved tectonically in Mississippian and Pennsylvanian time. Middle Pennsylvanian (Desmoinesian) northwest-southeast contraction resulted in thin-skinned folding and faulting, uplift, and erosion. These data require reinterpretation of the tectonic setting at the time of the Ancestral Rocky Mountains orogeny and suggest that plate convergence on the west side of the continent played a significant role in late Paleozoic tectonics of the North American continent. [ABSTRACT FROM AUTHOR]

This paper examines research on learning styles as related to online learning for adult learners. There is much disagreement regarding the definition of learning style. This paper defines it as an individual's preferred way of learning. The focus is on the extent to which learning styles are able to predict student success (e.g., grades, attitudes). The paper discusses nine different instruments that were used in various studies. Curry's model, which uses the metaphor of the layers of an onion, is used to categorize the instruments by theme for the sake of comparison. Criticisms of learning style research include: the vagueness of the construct "learning style"; the fact that the instruments are self-assessments; mixed results from research that searched for a relationship with online learning; and the difficulty of comparing different studies when online learning can include many different methods and technologies. Finally, I reach a conclusion regarding the suitability of studying the relationship of learning styles and success in online courses.

A compact stand-alone PV power system was recently designed and built to run an air sampler .for environmental monitoring at the Nevada Test Site. This paper presents an overview of the system design and analysis of some of the recorded daily cycles of various power flows during the summer period. The system long-term performance during both high and low solar resource periods is simulated with the computer code PVFORM using historical weather data. [ABSTRACT FROM AUTHOR]

A weakly sorbing cation, lithium, will be used as a reactive tracer in upcoming field tracer tests in the saturated alluvium south of Yucca Mountain, Nevada. One objective of the field tests is to determine how well field-scale reactive transport can be predicted using transport parameters derived from laboratory experiments. This paper describes several laboratory lithium batch sorption and column transport experiments that were conducted using ground water and alluvium obtained from the site of the planned field tests. In the batch experiments, isotherms were determined over 2.5 orders of magnitude of lithium concentrations, corresponding to the range expected in the field tests. In addition to measuring equilibrium lithium concentrations, concentrations of other cations, namely Na+, K+, and Ca2+, were measured in the batch tests to determine Li+-exchangeable equilibria. This information was used in conjunction with alluvium cation exchange capacity measurements to parameterize a three-component cation-exchange model (EQUIL) that describes lithium sorption in the alluvium system. This model was then applied to interpret the transport behavior of lithium ion in saturated alluvium column tests conducted at three different lithium bromide injection concentrations. The concentrations were selected such that lithium ion either dominated, accounted for a little over half, or accounted for only a small fraction of the total cation equivalents in the injection solution. Although tracer breakthrough curves differed significantly under each of these conditions, with highly asymmetric responses occurring at the highest injection concentrations, the three-component cation-exchange model reproduced the observed transport behavior of lithium and the other cations in each case with a similar set of model parameters. In contrast, a linear Kd-type sorption model could only match the lithium responses at the lowest injection concentration. The three-component model will be used to interpret the field tests, with the expectation that it will help refine estimates of effective flow porosity, particularly if the lithium response curves are asymmetric. [Copyright &y& Elsevier]

This paper presents several different conceptual models of the Large Hydraulic Gradient (LHG) region north of Yucca Mountain and describes the impact of those models on groundwater flow near the potential high-level repository site. The results are based on a numerical model of site-scale saturated zone beneath Yucca Mountain. This model is used for performance assessment predictions of radionuclide transport and to guide future data collection and modeling activities. The numerical model is calibrated by matching available water level measurements using parameter estimation techniques, along with more informal comparisons of the model to hydrologic and geochemical information. The model software (hydrologic simulation code FEHM and parameter estimation software PEST) and model setup allows for efficient calibration of multiple conceptual models. Until now, the Large Hydraulic Gradient has been simulated using a low-permeability, east–west oriented feature, even though direct evidence for this feature is lacking. In addition to this model, we investigate and calibrate three additional conceptual models of the Large Hydraulic Gradient, all of which are based on a presumed zone of hydrothermal chemical alteration north of Yucca Mountain. After examining the heads and permeabilities obtained from the calibrated models, we present particle pathways from the potential repository that record differences in the predicted groundwater flow regime. The results show that Large Hydraulic Gradient can be represented with the alternate conceptual models that include the hydrothermally altered zone. The predicted pathways are mildly sensitive to the choice of the conceptual model and more sensitive to the quality of calibration in the vicinity on the repository. These differences are most likely due to different degrees of fit of model to data, and do not represent important differences in hydrologic conditions for the different conceptual models. [Copyright &y& Elsevier]

This paper presents a numerical study on the response of the unsaturated zone (UZ) system of Yucca Mountain to heat generated from decaying radioactive wastes emplaced at the proposed repository. The modeling study is based on the current thermal–hydrological (TH) mountain-scale model, which uses a locally refined 2D north–south cross-section and dual-permeability numerical approach. The model provides a prediction of the mountain-scale TH response under the thermal-load scenario of 1.45 kW/m, while accounting for future climatic changes and the effects of drift ventilation. The TH simulation results show that ventilation of the repository drifts has a large impact on thermal–hydrologic regimes and moisture-flow conditions at the repository. In both cases, with and without ventilation, the TH model predicts dry or reduced liquid saturation near the drifts for over 1000 years, during which liquid flux through the drifts is reduced to either zero or less than the ambient flux. Without ventilation, the model predicts higher temperatures at the repository, but no major moisture redistribution in the UZ except in the areas very near the heated drifts. [Copyright &y& Elsevier]

Performance assessment and design evaluation of the proposed repository at Yucca Mountain are facilitated by a thermohydrologic modeling tool that simultaneously accounts for processes occurring at a scale of a few tens of centimeters around individual waste packages and emplacement drifts, and accounts for processes at the multi-kilometer scale of the mountain. The most straightforward approach is to account for the 3-D drift- and mountain-scale dimensionality all within a single monolithic thermohydrologic model. This approach is too computationally expensive to be a viable simulation tool capable of addressing all waste-package locations in the repository. The Multiscale Thermohydrologic Model (MSTHM) is a computationally efficient alternative to addressing these modeling issues. In this paper, we describe the principal calculation stages to predict temperature, relative humidity, and liquid-saturation, as well as other thermohydrologic variables, in the drifts and in the host rock. Using a three-drift repository example (which is a scaled-down version of the proposed repository), we demonstrate the validity of the MSTHM approach against a nested monolithic thermohydrologic model. [Copyright &y& Elsevier]

This paper presents the application of parallel computing techniques to large-scale modeling of fluid flow in the unsaturated zone (UZ) at Yucca Mountain, Nevada. In this study, parallel computing techniques, as implemented into the TOUGH2 code, are applied in large-scale numerical simulations on a distributed-memory parallel computer. The modeling study has been conducted using an over-1-million-cell three-dimensional numerical model, which incorporates a wide variety of field data for the highly heterogeneous fractured formation at Yucca Mountain. The objective of this study is to analyze the impact of various surface infiltration scenarios (under current and possible future climates) on flow through the UZ system, using various hydrogeological conceptual models with refined grids. The results indicate that the 1-million-cell models produce better resolution results and reveal some flow patterns that cannot be obtained using coarse-grid modeling models. [Copyright &y& Elsevier]

A numerical model was used to simulate the flow and transport processes at the Busted Butte Field Test Site for the purpose of quantifying the effects of hydrogeologic conditions beneath the potential Yucca Mountain repository horizon. In situ experiments were conducted on a 10×10×7 m block comprising a layered Topopah Springs/Calico Hills formation with two imbedded faults. Tracer solution was continuously injected in eight parallel boreholes arranged on two horizontal planes. Twelve collection boreholes were emplaced perpendicular to the injection holes and were both horizontal and inclined. Solution samples were collected regularly using a sampling assembly consisting of an inverted membrane and sorbing-paper sampling pads. Comparisons between measurements and predictions show that, except for the occasional drops of concentrations observed in the field, the current model is able to capture the general characteristics of the system with varying levels of agreement using laboratory-measured mean hydraulic properties. Simulation results and field observations revealed a capillary-driven flow in the system. Good quantitative agreement is generally observed for near-field boreholes, however, this agreement deteriorates and the simulated solute concentration is underestimated at boreholes farther away from the injection points. Increasing the spatial resolution of the simulation improves the model predictions only to a limited extent. Scaling issues may need to be considered to describe flow and transport events, as the travel distance becomes large. [Copyright &y& Elsevier]

Water managers increasingly are faced with the challenge of building public or stakeholder support for resource management strategies. Building support requires raising stakeholder awareness of resource problems and understanding about the consequences of different policy options. One approach that can help managers communicate with stakeholders is system dynamics modeling. Used interactively in a public forum, a system dynamics model can be used to explain the resource system and illustrate the effects of strategies proposed by managers or suggested by forum participants. This article illustrates the process of building a strategic-level system dynamics model using the case of water management in Las Vegas, Nevada. The purpose of the model was to increase public understanding of the value of water conservation in Las Vegas. The effects of policies on water supply and demand in the system are not straightforward because of the structure of the system. Multiple feedback relationships lead to the somewhat counterintuitive result that reducing residential outdoor water use has a much greater effect on water demand than reducing indoor water use by the same amount. The model output shows this effect clearly. This paper describes the use of the model in research workshops and discusses the potential of this kind of interactive model to stimulate stakeholder interest in the structure of the system, engage participant interest more deeply, and build stakeholder understanding of the basis for management decisions. [Copyright &y& Elsevier]

Most universities now offer a plethora of on-campus courses for students to choose from. However, many students are not able to take campus-based courses due to distance or timetabling limitations. An important option for such students has always been distance education. This paper focuses on the use of multimedia delivery technologies and their effect on how distance education is received and used by students. It discusses the creation, delivery and evaluation of an online version of an existing campus-based module. A quantitative comparison of the two methods of course delivery has been made and the results are then discussed in terms of examination performance and attrition. Confirming the initial hypothesis, no significant differences were found. [ABSTRACT FROM AUTHOR]

A special capstone course for senior electrical and mechanical engineering students has been developed at the University of Nevada, Reno. The class also includes MBA students from the College of Business Administration. All phases of new product development including innovation, patent law, product liability, business, sales, marketing and venture capital are covered. This paper presents a brief description of the course and the assessment results. The assessment results indicate that the learning objectives are being met and that students strongly feel that invention and entrepreneurship should be part of the engineering curriculum. [ABSTRACT FROM AUTHOR]

This paper is an investigation of three simple normalization procedures for suppressing the effects of solar heating and topography in daytime thermal data. The first method is the hyperspherical direction cosine (HSDC) transformation, which separates the pixel vector into an illumination/albedo component and a spectral component. The second method, a model correction, is based on the assumption that, once an elevation correction using the normal lapse rate has been applied, temperatures are proportional to the instantaneous solar heating as measured by the cosine of the solar illumination incidence angle. The third method is a statistic-empirical correction. These three normalization methods were applied to a test site in the Humboldt Range, Pershing County, Nevada, using Landsat Thematic Mapper data. It was found that geological patterns were much clearer in the normalized data than in the original temperature information. The HSDC correction brought out lithological differences, helped discriminate between gravels and spectrally similar sedimentary rocks and resulted in a significant increase in classification accuracy. The model correction appeared to inadequately compensate for the cool temperatures found at high elevations, and therefore underestimates the actual decline in temperature with elevation. Nevertheless, the rock contacts are relatively clear, and the classification produced the second highest overall accuracy. The statistic-empirical classification resulted in improved elevation correction, but it over-corrected north-facing slopes and produced only intermediate improvements in accuracy. [ABSTRACT FROM AUTHOR]

This paper describes a unique collaboration between the College of Education (COE) and the Center for Academic Enrichment and Outreach (CAEO) at the University of Nevada Las Vegas. Here we describe our efforts to improve student science performance in traditionally underachieving urban middle schools by embracing our state's highly qualified teacher requirements implemented to gain compliance with the No Child Left Behind Act of 2001 (NCLB). The focus of our collaborative intervention is improving the content and pedagogical content knowledge of a group of existing teachers by fostering a professional learning community among teachers, scaffolding technology within a new master's degree program, and working to build a partnership to provide the necessary technology infrastructure. This paper outlines our intervention from both a practical and theoretical perspective.

In the American West, wildfires and earthquakes are increasingly threatening the archaeological, historical, and tribal resources that define the collective identity and connection with the past for millions of Americans. The loss of said resources diminishes societal understanding of the role cultural heritage plays in shaping our present and future. This paper examines the viability of employing stationary and SLAM-based terrestrial laser scanning, close-range photogrammetry, automated surface change detection, GIS, and WebGL visualization techniques to enhance the preservation of cultural resources in California. Our datafication approach combines multi-temporal remote sensing monitoring of historic features with legacy data and collaborative visualization to document and evaluate how environmental threats affect built heritage. We tested our methodology in response to recent environmental threats from wildfire and earthquakes at Bodie, an iconic Gold Rush-era boom town located on the California and Nevada border. Our multi-scale results show that the proposed approach effectively integrates highly accurate 3D snapshots of Bodie's historic buildings before/after disturbance, or post-restoration, with surface change detection and online collaborative visualization of 3D geospatial data to monitor and preserve important cultural resources at the site. This study concludes that the proposed workflow enhances the monitoring of at-risk California's cultural heritage and makes a call to action to employ remote sensing as a pathway to advanced planning. [ABSTRACT FROM AUTHOR]

The Flattop critical assembly was built and operated from 1958 through 2004 at the Pajarito Site (Technical Area-18), home to the Los Alamos Critical Experiments Facility. Flattop was disassembled in 2005 and refurbished over the course of 3 years. In 2008, Flattop was installed in the National Criticality Experiments Research Center (NCERC) located in the Device Assembly Facility at the Nevada National Security Site. Startup of Flattop with a uranium core occurred in 2011. This paper details the first 10 years of Flattop operations at NCERC (2011–present). [ABSTRACT FROM AUTHOR]

• Open-source code to stochastically invert five typical geothermal datasets. • Tests four algorithms: genetic algorithm, MCMC, simulated annealing and NSGA. • Algorithms create complex geologically realistic structural models. • Tested successfully on real data from Patua Geothermal Field in Nevada, USA. • Method helps advance fault targeting capability in geothermal reservoirs. Financial risk due to geological uncertainty is a major barrier for geothermal development. Production from a geothermal well depends on the unknown location of subsurface geological structures, such as faults that contain hydrothermal fluids. Traditionally, geoscientists collect many different datasets, interpret the datasets manually, and create a single model estimating faults' locations. This method, however, does not provide information about the uncertainty regarding the location of faults and often does not fully respect all observed datasets. Previous researchers investigated the use of stochastic inversion schemes for addressing geological uncertainty, but often at the expense of geologic realism. In this paper, we present algorithms and open-source code to stochastically invert five typical datasets for creating geologically realistic structural models. Using a case study with real data from the Patua Geothermal Field, we show that these inversion algorithms are successful in finding an ensemble of structural models that are geologically realistic and match the observed data sufficiently. Geoscientists can use this ensemble of models to optimize reservoir management decisions given structural uncertainty. [ABSTRACT FROM AUTHOR]

This paper reports the results of a randomized controlled trial evaluating "We Have Skills," a brief curriculum designed to teach early elementary students academic and social skills as well as improve teacher efficacy in classroom management. Intervention efficacy was tested with 127 teachers, randomly assigned to condition, and 2,817 of their students. On key outcomes of student academically related behavioral skills and classroom adjustment, intervention teachers reported greater gains for their students than comparison teachers (Hedges's g [greater than or equal to] 0.19). Baseline scores moderated effects, demonstrating greater differences between conditions for initially struggling students. Intervention teachers also reported greater improvements on their sense of self-efficacy for classroom management and concerns about student behavior (|g| [greater than or equal to] 0.30) relative to comparison teachers. Effect sizes were similar to or greater than those reported for similar programs, and an economic analysis suggested that "We Have Skills" was less costly than many. The findings support cost-effective solutions that teach social-behavioral skills in early elementary grades--and suggest that such programs may be especially beneficial for students who struggle with academically related behaviors.

Studying the temporal and spatial evolution trends in earthquakes in an area is beneficial for determining the earthquake risk of the area so that local governments can make the correct decisions for disaster prevention and reduction. In this paper, we propose a new method for analyzing the temporal and spatial evolution trends in earthquakes based on earthquakes of magnitude 3.0 or above from 1980 to 2019 in California and Nevada. The experiment's results show that (1) the frequency of earthquake events of magnitude 4.5 or above present a relatively regular change trend of decreasing–rising in this area; (2) by using the weighted average center method to analyze the spatial concentration of earthquake events of magnitude 3.0 or above in this region, we find that the weighted average center of the earthquake events in this area shows a conch-type movement law, where it moves closer to the center from all sides; (3) the direction of the spatial distribution of earthquake events in this area shows a NW–SE pattern when the standard deviational ellipse (SDE) method is used, which is basically consistent with the direction of the San Andreas Fault Zone across the north and south of California; and (4) the spatial distribution pattern of the earthquake events in this region is found to be clustered using the global spatial autocorrelation analysis method. This study provides a new perspective for the exploration of the temporal and spatial evolution trends in earthquakes and understanding the earthquake risk in an area. [ABSTRACT FROM AUTHOR]

Yucca Mountain, NV, is being characterized for disposal of U.S. high-level nuclear waste, which consists predominantly of spent fuel from nuclear reactors and radioactive waste from reprocessing. In this paper, the program is presented in the context of global and U.S. nuclear energy systems and of international plans for high-level waste disposal. The potential impact of the proposed repository is discussed in the context of the U.S. Department of Energy's Total System Performance Assessment-Viability Assessment, the primary tool for assessing how the repository might operate. [ABSTRACT FROM AUTHOR]

X-ray films remain a key asset for high-resolution x-ray spectral imaging in high-energy-density experiments conducted at the National Ignition Facility (NIF). The soft x-ray Opacity Spectrometer (OpSpec) fielded at the NIF has an elliptically shaped crystal design that measures x rays in the 900–2100 eV range and currently uses an image plate as the detecting medium. However, Agfa D4 and D3sc x-ray films' higher spatial resolution provides increased spectral resolution to the data over the IP-TR image plates, driving the desire for regular use of x-ray film as a detecting medium. The calibration of Agfa D4 x-ray film for use in the OpSpec is communicated here. These calibration efforts are vital to the accuracy of the NIF opacity measurements and are conducted in a previously un-studied x-ray energy range under a new film development protocol required by NIF. The absolute response of Agfa D4 x-ray film from 705 to 4620 eV has been measured using the Nevada National Security Site Manson x-ray source. A broader range of energies was selected to compare results with previously published data. The measurements were taken using selected anodes, filters, and applied voltages to produce well-defined energy lines. [ABSTRACT FROM AUTHOR]

Presents a response to the discussion by Mehmet Cakir and Atilla Aydin in an article titled `Kinematics and timing of Tertiary extension in the western Lake Mead region, Nevada,' in the August 1995 issue of the Geological Survey of America Bulletin, regarding the poor representation of some aspects in the paper presented by Duebendorfer and Simpson's in 1994.

Focuses on the activities for the March meeting of the American Physical Society in Las Vegas, Nevada. Conduction of a free on-line training workshop; Schedule for the invited sessions; Enumeration of awardee physicists. INSET: Invited papers and special sessions.

This paper examines several dimensions of public opposition to the proposed siting of the high-level nuclear waste repository at Yucca Mountain. In order to provide a context for the public's view of the repository in metropolitan Clark County, both governmental studies of the repository siting process are analyzed, as well as elements of the Nuclear Waste Policy Act. This analysis suggests that one potentially key component of the public's opposition to the siting, as well as their perceptions of risk of the facility, may be the result of a lack of trust in the Department of Energy. Empirical analysis of survey data collected in Nevada in 1988 confirms the strong relationship between political trust and repository risk perceptions. [ABSTRACT FROM AUTHOR]

This paper overviews child welfare in America as it relates to the changing views and needs of chidren. World attitudes toward children, early American child welfare values and services, foster care and in-home Family treatment programs, and family preservation movement have been described within the contexts of new economic, social, and political pressures in America. A case study of the first family preservation program in Nevada has been provided to illustrate how families who were "at risk" for removal of child from home due to child abuse or neglect have been served. The case study also highlights interagency cooperation and linkage which helped in serving the families in crisis. A three-year follow up of the program indicated that this program revolutionized many other child welfare services throughout the State of Nevada. [ABSTRACT FROM AUTHOR]

This paper examines the possibility of criticality in a nuclear waste repository. The estimated probabilities are rough bounds and do notentirely dismiss the possibility of a critical condition; however, they do point to the difficulty of creating conditions under which a critical mass could be assembled (i.e., corrosion of containers, separation of neutron absorbers from the fissile material and collapse or precipitation of the fissile material). In addition, should a criticality occur in or near a container, the bounding consequence calculations showed that fissions from one critical event are quite small (< ~1020 fissions, if similar to aqueous and metal accidents and experiments). Furthermore, a reasonable upper bound of total critical events of 1028 fissions corresponds to only 0.1% of the number of fissions represented by the spent nuclear fuel inventory in a repository containing 70,000 metric tons of heavy metal (MTHM) (the expected size for the proposed repository at Yucca Mountain, Nevada. [ABSTRACT FROM AUTHOR]

No public policy issue has been as difficult as high-level nuclear waste. Debates continue regarding Yucca Mountain as a disposal site, and -- more generally -- the appropriateness of geologic disposal and the need to act quickly. Previous research has focused on possible social, political, and economic consequences of a facility in Nevada. Impacts have been predicted to be potentially large and to emanate mainly from stigmatization of the region due to increased perceptions of risk. Analogous impacts from leaving waste at power plants have been either ignored or assumed to be negligible. This paper presents survey results on attitudes of residents in three counties where nuclear waste is currently stored. Topics include perceived risk, knowledge of nuclear waste and radiation, and impacts on jobs, tourism, and housing values from leaving waste on site. Results are similar to what has been reported for Nevada; the public is concerned about possible adverse effects from on-site storage of waste. [ABSTRACT FROM AUTHOR]

Organophosphate (OP) pesticide residues have been found in rain, snow, fog and air samples collected in the Sierra Nevada mountains. The fate of these residues in this ecosystem is poorly understood. A major component of the Sierra Nevada ecosystem is the varied plant biomass. Interaction between chemicals vapors and plant material has been demonstrated for various semivolatile organic compounds. This research addresses the hypothesis that the extensive forests of the western slopes of the Sierra Nevada mountains, which lie in the predominant downwind direction from the agricultural Central Valley of California, might serve as sinks for airborne OPs. The main paths of vapor‐leaf interaction are cuticular and stomatal. More specifically, interactions may include sorption of residues to surface dust particles, or to the needle surface, solubilization in the cuticular wax of the needle, and penetration to the interior of the needle either by absorption through the stomata or migration through the cuticle. Analytical methods, which can separately assess surface, cuticle adsorbed, cuticle dissolved, and internal needle tissue residues, have been applied in two experimental situations. One involved measuring the vapor‐needle distribution coefficient for several OPs exposed as vapors to pine branches in a laboratory chamber. A second, involving air and needle analyses for trees placed in, and downwind from a diazinon‐treated orchard, provided outdoor distribution coefficients for comparison with chamber data. This paper addresses these two experimental situations, along with preliminary calculations of possible loading values for forests in the Sierra Nevadas. The results support the hypothesis that forests act as sinks for airborne pesticide vapors. [ABSTRACT FROM AUTHOR]

One of the major reasons for the reluctance to legalize many of the popular forms of gambling is the belief that these forms are particularly difficult to control honestly. It is generally believed that organized crime has been able to undermine regulatory mechanisms. This paper reports on the difficulties and successes of the Nevada Gambling Control Board's efforts to deal with a sophisticated and complex form of gambling organization and compares and contrasts that regulation with the regulation of casino gambling in England. [ABSTRACT FROM AUTHOR]

This paper examines the effects of legalization on illegal gambling participation using a multivariate analysis to adjust for the influence of demographic variables. In addition, the incidence of illegal gambling m a nationwide sample was compared with the incidence reported by Nevada residents. Games with similar structures and psychological characteristics appear to be complementary. That is, people who participate in one tend to participate in the other as well, regardless of their legal status. Dissimilar games operate as substitutes for each other. [ABSTRACT FROM AUTHOR]

This paper describes a recent effort to pass some "anti-cult" legislation in Nevada. The effort exemplified a new consumer-oriented approach to such matters that seeks to treat religious groups similarly to charitable organizations, and implicitly defines religion as a consumer good to be regulated by government. The bill would have authorized a number of civil and state actions against religions, it evoked considerable controversy before being defeated, with Mormon legislators playing a key role in the bill's defeat. A number of more liberal and moderate members of the legislature supported the legislation, however Implications of this approach are discussed. [ABSTRACT FROM AUTHOR]