2,519 research outputs found
Cornell University remote sensing program
There are no author-identified significant results in this report
All about a line: The Sidney-Black Hills Trail\u27s impact on the cultural landscape of western Nebraska and South Dakota
When driving through western Nebraska and South Dakota, one can identify artifacts and signs of an earlier highway. In some places the wagon ruts and foundations of previous foundations are still visible; in other places the highway is represented through markers and signs erected by historically minded organizations. The presence of these signs, markers, and wagon ruts mark representations o f the Sidney-Black Hills Trail on the landscape. The presence o f the wagon ruts and settlement foundations mark a representation of the trail as it was and gives one a view of the real American West; a West that chronicles the Black Hills gold rush in 1874-1880. The presence o f the historical markers and signs, both private and governmental, may represent the Trail as it was, and is, in the Mythic West. This theory of the American W est and the Mythic W est is what I am exploring in my study of the cultural landscape o f the Sidney-Black Hills Trail. By comparing information from the National Register of Historic Places, the Nebraska and South Dakota Historic Markers programs, signs, and local resources to historic documents I find that the “West” and the “Mythic West” have merged, giving the impression that the present-day interpretations of the Trail are the historic interpretations of the Trail
Cornell University remote sensing program
Aircraft and satellite remote sensing technology were applied in the following areas: (1) evaluation of proposed fly ash disposal sites; (2) development of priorities for drainage improvements; (3) state park analysis for rehabilitation and development; (4) watershed study for water quality planning; and (5) assistance project-landfill site selection. Results are briefly summarized. Other projects conducted include: (1) assessment of vineyard-related problems; (2) LANDSAT analysis for pheasant range management; (3) photo-historic evaluation of Revolutionary War sites; and (4) thermal analysis of building insulation. The objectives, expected benefits and actions, and status of these projects are described
From “Spring Break” to “Reading Days”: Contingency, Relations of Power, and Positionalities in Experiences of Overwork During Academic Breaks
In this article, the authors analyze the impacts of their university eliminating Spring Break and replacing it with intermittent Reading Days during the Covid-19 pandemic. With particular attention to contingency, relations of power, and positionalities, they offer narratives of their lived experiences with Reading Days as a graduate student (Author 1) and as a pre-tenure faculty member (Author 2). They also offer analysis of the public conversations surrounding the institutional decision. The article addresses how the particularities of the narratives are symptomatic of a culture of overwork that predates and continues beyond the moment in time and place of the context described. Authors offer takeaways and calls to action that invite readers to continue examining and intervening in larger, persistent structures of inequity—particularly as they come to bear on academic breaks
Confinement-induced drift in Marangoni-driven transport of surfactant:a Lagrangian perspective
Successive drops of coloured ink mixed with surfactant are deposited onto a thin film of water to create marbling patterns in the Japanese art technique of Suminagashi. To understand the physics behind this and other applications where surfactant transports adsorbed passive matter at gas-liquid interfaces, we investigate the Lagrangian trajectories of material particles on the surface of a thin film of a confined viscous liquid under Marangoni-driven spreading by an insoluble surfactant. We study a model problem in which several deposits of exogenous surfactant simultaneously spread on a bounded rectangular surface containing a pre-existing endogenous surfactant. We derive Eulerian and Lagrangian formulations of the equations governing the Marangoni-driven surface flow. Both descriptions show how confinement can induce drift and flow reversal during spreading. The Lagrangian formulation captures trajectories without the need to calculate surfactant concentrations; however, concentrations can still be inferred from the Jacobian of the map from initial to current particle position. We explore a link between thin-film surfactant dynamics and optimal transport theory to find the approximate equilibrium locations of material particles for any given initial condition by solving a Monge-Ampère equation. We find that, as the endogenous surfactant concentration δ vanishes, the equilibrium shapes of deposits using the Monge-Ampère approximation approach polygons with corners curving in a self-similar manner over lengths scaling as δ1/2. We explore how Suminagashi patterns may be produced by using computationally efficient successive solutions of the Monge-Ampère equation
Measuring Streambank Erosion: A Comparison of Erosion Pins, Total Station, and Terrestrial Laser Scanner
Streambank erosion is diffcult to quantify; models and field methods are needed to assess this important sediment source to streams. Our objectives were to (1) evaluate and compare three techniques for quantifying streambank erosion: erosion pins, total station, and laser scanning, (2) spatially assess streambank erosion rates in the Indian Mill Creek watershed of Michigan, USA, and (3) relate results with modeling of nonpoint source pollution. We found large absolute and relative errors between the different measurement techniques. However, we were unable to determine any statistically significant differences between techniques and only observed a correlation between total station and laser scanner. This suggests that the three methods have limited comparability and differences between measurements were largely not systemic. Further, the application of each technique should be dependent on site conditions, project goals, desired resolution, and resources. The laser scanner collected high-resolution data on clear, barren streambanks, but the erosion pin and total station were more representative of complex vegetated banks. Streambank erosion rates varied throughout the watershed and were influenced by fluvial processes. We estimate that streambank erosion contributed 28.5% of the creek’s total sediment load. These findings are important to address sources of watershed impairments related to sedimentation, as choosing an applicable technique for individual purposes can help reduce the challenges and costs of a streambank erosion study
Reducing effects of dispersal on the bias of 2-sample mark-recapture estimators of stream fish abundance
The 2-sample mark-recapture method with Chapman’s estimator is often used by inland fishery managers to estimate the reach-scale abundance of stream fish. An important assumption of this method is that no dispersal into or out of the study reach occurs between the two samples. Violations of this assumption are probably common in practice, but their effect on bias (systematic error) of abundance estimates is poorly understood, especially in small populations. Estimation methods permitting dispersal exist but, for logistical reasons, often are infeasible for routine assessments in streams. The purpose of this paper is to extend available results regarding effects of dispersal on the bias of Chapman’s estimator as applied to reach-scale studies of stream fish abundance. We examine for the first time the joint effects of dispersal and sampling variation on the bias of this estimator. To reduce the bias effects of dispersal, we propose a modified sampling scheme in which the original study reach is expanded, a central subreach is sampled during the mark session (sample 1), and the entire reach is sampled during the recapture session (sample 2). This modified sampling scheme can substantially reduce bias effects of dispersal without requiring unique marking of individual fish or additional site visits. Analytical and simulation results show that sampling variation tends to create negative bias with respect to study-reach abundance, while dispersal tends to create positive bias; the net effect can be positive, negative, or zero, depending on the true abundance, capture probabilities, and amount and nature of dispersal. In most cases, simply expanding the study reach is an effective way to reduce dispersal-related bias of Chapman’s estimator, but expanding the study reach and employing the modified sampling scheme we propose is a better alternative for accurately estimating abundance with the same level of sampling effort
Measures Matter: Scales for Adaptation, Cultural Distance, and Acculturation Orientation Revisited
Building upon existing measures, four new brief acculturation scales are presented, measuring sociocultural adaptation, psychological adaptation, perceived cultural distance, and acculturation orientation. Following good scale reliability in initial samples, the English scales were translated into nine different languages (Chinese, French, German, Italian, Japanese, Portuguese, Spanish, Thai, and Turkish). The translated scales were administered to a large sample of sojourners (N = 1,929), demonstrating good reliability and adequate structural equivalence across languages. In line with existing theory, sociocultural adaptation and psychological adaptation were positively correlated, and showed a negative association with perceived cultural distance. General measures of well-being were correlated with adaptation and distance, with better adaptation relating to higher well-being, and more distance relating to lower well-being. Acculturation orientation toward the home and host culture were measured separately and a weak negative correlation was found between the two, supporting their independence. Arguing against dichotomization, these subscales were analyzed as continuous variables. Regression analysis showed sojourners to be better adapted, if they were oriented more toward the host culture and less toward the home culture. These new scales are proposed as alternatives to existing measures
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