Browsing by Subject "density"

Now showing 1 - 6 of 6
  • Thumbnail Image
    Item
    Bird Point Counts from Downtown Minneapolis During the 2016 Breeding Season
    (2018-11-15) Anderson, Abigail W; awoodsanderson at g m a i l (dot) com; Anderson, Abigail W
    These data document species richness and abundance of the local breeding bird community in downtown Minneapolis, Minnesota. I used a conventional point count methodology (Bibby et al. 2000) to sample a total of 16 locations (or transect areas) all with a 50-meter radius. All observation periods took place between 1 June and 5 July 2016. The data can be used to derive species abundance indices and bird density. Furthermore, the data contain elements that permit more sophisticated statistical modeling such as time-depletion (removal) or distance sampling techniques.
  • No Thumbnail Available
    Item
    City of Edina Density Study
    (Resilient Communities Project (RCP), University of Minnesota, 2024) Briggs, Kenton; Leaf, Holly; Menhennet, Johnny; Olberding, Greg; Thompson, Jem; Wu, Yuping
    This project was completed through a partnership between the City of Edina and the University of Minnesota’s Resilient Communities Project (https://rcp.umn.edu/). The goal of this project was to investigate if the City of Edina’s 2030 population density targets are adequate to meet its transportation and climate goals, analyze how this density target aligns with the City’s current comprehensive plan, and recommend site-specific and general strategies for increasing density to meet the target goal. City of Edina project lead Matthew Gabb collaborated with a team of students in Dr. Nichola Lowe’s course PA 8081, which performed policy and literature reviews, ran multivariate regression analyses to determine which factors impact vehicle miles traveled and greenhouse gas emissions, modeled potential density scenarios and relevant policy changes to introduce greater density, and made final recommendations for how the city might best achieve its transportation and climate goals. A final student report and presentation from the project are available.
  • Thumbnail Image
    Item
    Experimental study of density induced plunging flow into reservoirs and costal regions
    (1998-10) Johnson, Thomas R.; Stefan, Heinz G.
    The inflow entering a lake or reservoir is probably not precisely of the same density as the lake or reservoir. If the density of the inflow is less than the receiving water, the inflow will float on the surface. If the density of the inflow is greater than that of the receiving water, the inflow sinks below the surface, forming a density current. This phenomenon is referred to as "plunging" and the location where the inflow dives below the surface as the "plunge point" or "plunge line." The plunging phenomenon can be defined as the transition from open channel flow to a stratified underflow. Information is available on underflows (Ashida and Egashira, 1977; Ellison and Turner, 1959; Turner, 1973) but does not include the plunging process itself. The plunging flow can entrain some of the ambient water, thus changing the character of the inflow itself. In Minnesota plunging flow can occur in the late summer and fall when lakes are still warm from the heat absorbed in the summer and the inflowing streams are cool. It also occurs after cold weather spells in midsummer. Plunging flow can also occur if the excess density of the inflow is produced by suspended material or dissolved substances. The plunging phenomenon is not fully understood even when the receiving water is of uniform density. The situation becomes more complex when a plunging flow enters a stratified lake or reservoir where the plunging flow will entrain ambient water of increasing density as it sinks. Not only will the rate of dilution determine to which depth the underflow will sink in a stratified reservoir, lake or impoundment (Elder and Wunderlich, 1972), but it is a parameter which controls the location of the plunge line. One-dimensional unsteady water quality models require knowledge of plunging flow to be able to predict into which layer in a stratified lake or reservoir an inflow will enter. Akiyama and Stefan (1987) and Farrell and Stefan (1986) provide literature reviews of previous work on plunging flows. Akiyama and Stefan (1987) list previous studies indicating that the dilution rate of plunging flows ranges from 0 to 500% in field studies and 0 to 200% in laboratory studies. These reviews, however, indicate that most of the previous experimental and analytical work dealt with sloping parallel sided (two-dimensional) or unconfined sloping configurations. Akiyama and Stefan (1987) conducted experiments and developed an integral type analysis of plunging in a mildly diverging horizontal channel.Farrell and Stefan (1986) used numerical analysis to solve the entire flow field driven by a plunging flow in a 2-D reservoir. The geometrical configurations modeled were either mildly diverging horizontal channels or parallel sided sloping channels, which lend themselves to two-dimensional analysis. Negatively buoyant flow in a strongly diverging channel where the inflow separates from the sidewalls has not been the subject of laboratory or analytical studies, probably due to the three-dimensional nature of the flow field. In order to provide information on plunging flow an experimental study dealing primarily with strongly diverging channels (Fig. 1-1) was conducted at St. Anthony Falls Hydraulic Laboratory_ This type of flow can be related to previous analytical and experimental studies which deal with diffuser flow, jet flow, and stratified flow. Previous work done in these three subject areas will be related to the experimental results presented in the body of this study. In addition, a set of field measurements will be reported and related to laboratory experimental results.
  • Thumbnail Image
    Item
    Growth Rates and Variances of Unexploited Wolf Populations in Dynamic Equilibria: Data, R Code, and Supporting Results
    (2014-07-18) Fieberg, John R; Mech, David; jfieberg@umn.edu; Fieberg, John R
    These files contain data and R code (along with associated output from running the code) supporting all results reported in: Mech, D. and J. Fieberg. 2014. Growth Rates and Variances of Unexploited Wolf Populations in Dynamic Equilibria. Wildlife Society Bulletin. In Mech and Fieberg (2014), we analyzed natural, long-term, wolf-population-density trajectories totaling 130 years of data from three areas: Isle Royale National Park in Lake Superior, Michigan; the east-central Superior National Forest in northeastern Minnesota; and Denali National Park, Alaska. We fit density-independent and Ricker models to each time series, allowing for 3 different assumptions regarding observation error (no error, Poisson or Log-normal observation error). We suggest estimates of the population-dynamic parameters can serve as benchmarks for comparison with those calculated from other wolf populations repopulating other areas.
  • Thumbnail Image
    Item
    Housing and Density Options Study
    (Resilient Communities Project, University of Minnesota, 2012-12) Creed, Jonathan; Giant, Joseph; Johnson, Wesley; Nesse, Kristina; Oltz, Brent
    This project was completed as part of the 2012-2013 Resilient Communities Project (rcp.umn.edu) partnership with the City of Minnetonka. As the result of a housing marketing study, the City of Minnetonka discovered the need to develop a more diverse range of housing options for residents, with housing of various types, sizes, price points, and densities. Minnetonka project lead Loren Gordon worked with students in PA 8203: Neighborhood Revitalization, to compile a housing density research report and toolkit, using the Minnetonka 2030 Comprehensive Guide Plan (2008) and the Opportunity City Pilot Program Report (2009) as a foundation. The students' final report, presentation, and poster are available.
  • Thumbnail Image
    Item
    The Influence of Pattern and Color Interaction in Object Color Preference
    (2019-05) Nahhas, Shuruq
    A mixed method study was conducted to examine the influence of pattern density and color contrast in object color preference for two-color combinations. This study answered four questions: What colors are selected by participants when shown a set of solid colored hues? Which density and contrast levels are preferred by participants? Which objects do participants prefer for a specific colored pattern swatch? Why? A convenience sample of 30 undergraduate design students from the College of Design at the University of Minnesota participated in this research. Four main conclusions were the result of this research: First, color influences pattern more than pattern influences color. The same pattern of the same density appears different and would be preferred for big or small objects based on its colors. Second, the most preferred combinations have medium value or chroma (middle), low chroma (muted), high value (light). The least preferred combinations have very high chroma (saturated), or low value (dark). Third, the most preferred color combinations create sufficient contrast (high or mid) between the foreground element and background. The least preferred color combinations create low or no contrast between the foreground element and background. Fourth, the participants’ responses were varied between subjective and objective. Some responses were more subjective than objective. In this case, the participants related their preferences to their personal life and experience. Other responses were more objective than subjective. In this case, the participants related their preferences to the properties of color, pattern and the object size or purpose.