Now showing items 3776-3795 of 14780


      Simpson, Eugene S.; Boling, James Keith, 1949- (The University of Arizona., 1987)
      Ground-water pumping has led to subsidence and many earth fissures in unconsolidated alluvial basins in Arizona. Earth fissures result from tensile failure; however, mechanisms producing the tensile forces are not well understood. Horizontal displacement measurements (opening and closing) of seven earth fissures were made semi-monthly during 1976 to 1982 in the lower Santa Cruz Basin and Avra Valley. Permanent and temporary short-base extensometers with a resolution of ±2.54 μm were developed and perfected which use dial gauges and transducers. Among different fissure movements, the greatest total was 41.44 mm, the greatest single opening was 31 mm, and exclusive of that, the greatest net opening was 16.54 mm. Fissures opened and closed repeatedly, exhibiting smooth movements over long periods of time, punctuated by sudden jumps. Generally, old and new earth fissures exhibited similar behavior. Earth fissures tend to close after long, dry periods and to open after heavy rainfalls. The earth fissure with the greatest movement was closest to the area of the greatest subsidence.

      Krieski, Mark. (The University of Arizona., 1984)
    • The East African Institute of Resource Planning and Management: A proposal

      Wilkin, Donovan C.; Nuwamanya-Matsiko, John Willis, 1950- (The University of Arizona., 1992)
      East Africa, a region in Africa south of the Sahara, is faced with many environmental and urban problems due to development and population growth impacting on the land, vegetation and wildlife. This region, at present, does not have its own trained manpower able to plan and manage the natural resources but also to minimize man's impact on these resources in order to achieve sustainable development in the region. The thesis of this study is that a regional institute of resource planning and management be established in one of the three countries in the region to meet this pressing need.
    • The Eccles-Jordan circuit using junction transistors

      Jones, Lincoln D. (The University of Arizona., 1956)
    • Ecohydrological Conditions Associated With The Distribution And Phenology Of The Pima Pineapple Cactus

      Papuga, Shirley A.; Breshears, David D.; Kidder, Amí Lynne; Papuga, Shirley A.; Breshears, David D.; McClaran, Mitchel P.; Law, Darin J. (The University of Arizona., 2015)
      Climate changes in temperature and precipitation are already occurring and are projected to further exhibit increasing temperature and precipitation extremes and increasing variation. Such increased temperature variation and decreased precipitation are likely to have a profound impact on vegetation communities, particularly in regions that are dominated by extreme temperatures and strongly seasonal precipitation events. Both temperature and precipitation are tightly linked to vegetation growth and distribution, and in regions such as the U.S. desert southwest, there are a number of rare and endangered species that have a particularly tight knit relationship with their environment. Here, I examine the relationship between these ecohydrological drivers and a specific, little- researched cactus: the Pima Pineapple Cactus (Coryphantha scheeri var. robustispina). C. scheeri is a small, hemispherical cactus that resides in the Santa Cruz and Altar Valleys of Southern Arizona, and very little is known about the conditions that promote C. scheeri distribution and growth. To provide information that may aide in managing this species, I investigate aspects of the distribution and the phenology of this species. With respect to distribution, I hypothesize that (H1) C. scheeri locations are associated with spatial physical and climatic data within its geographic limits. A framework describing the climatic associations of C. scheeri would enable species managers to take advantage of suitable habitat when opportunities arise. With respect to phenology, within established C. scheeri habitat we lack a clear understanding of the impact ecohydrological factors can have on reproduction and size. Therefore, I also hypothesize (H2) that C. scheeri flowering phenology is triggered by available moisture, which may be in the form of precipitation, humidity, or soil moisture. My results indicate that through the use of the classification tree, C. scheeri habitat is strongly associated with climatic and physical variables at a state-wide scale; these associations indicate large losses of suitable habitat under future projected climate scenarios. Additionally, I find that C. scheeri flowering phenology appears to be associated with precipitation and the resulting increase of soil moisture; the data are also suggestive that bud formation might be associated with water-year growing degree day. Because the results indicate a tight coupling with climatic variables, with most suitable habitat within the current range in Arizona projected to be lost under future climate, I suggest managers may be inclined to increase monitoring C. scheeri in an ecohydrological context relative to the variables identified here and to consider conditions and locations where supplemental watering or microclimate amelioration could be beneficial for the species.
    • An ecological analysis of the quality fishery for rainbow trout in Becker Lake

      Satterthwaite, Thomas Dee, 1953- (The University of Arizona., 1978)
    • Ecological and consumer group variation in expedient chipped stone technology of the Pueblo period: An exploratory study in the Silver Creek drainage, Arizona

      Mills, Barbara J.; Kaldahl, Eric James, 1971- (The University of Arizona., 1995)
      Lithic raw material variety and abundance reveals the technological utility of different source materials from 20 chipped stone surface collections in the Silver Creek area of east-central Arizona, from sites dating between the 9th and 14th centuries. A rich raw material environment obviates distance-from-source constraints, freeing debitage analysis from traditional spatial interpretations regarding the intensity of reduction. Rather the intensity of reduction and the frequency of distinct material types in each assemblage reflects the impact of social organization, community size, exchange and subsistence variation on the organization of chipped stone technology.
    • Ecological Assessment of Red-Bellied Squirrels (Sciurus Aureogaster) Introduced to Elliott Key, Florida

      Koprowski, John L.; Palmer, Geoffrey Hamilton; Matter, William; Conway, Courtney (The University of Arizona., 2012)
      Introduced species present one of the greatest threats to biodiversity of native species, and knowledge of introduced species ecology is imperative for the development of management plans to ensure conservation of native species populations. We sought to determine the distribution and nesting behavior of an introduced population of red-bellied squirrels (Sciurus aureogaster) on islands of the Florida Keys currently managed as part of Biscayne National Park, and document potential for the species to impact native flora and fauna. Squirrels were difficult to observe in the dense vegetation of the subtropical forest, so we relied on their leaf nests, which were highly visible in the canopy of trees, to determine current presence and distribution on the Park's islands. We found nests throughout the mixed-hardwood forests of Elliott Key and Sands Key, and also documented a single, old nest on Old Rhodes Key, the first ever documentation of the species that far south in the Upper Keys. Nests were located in tall trees with more canopy linkages than random focal trees, and nests were placed in the upper canopy on the north side of the nest tree more often than expected by chance. Squirrels selected West Indies mahogany (Swietenia mahagoni) to place nests more often than available in the forest. Squirrels used areas with greater tree density and canopy cover, but lower recent hurricane damage and fewer woody shrub stems, than areas available at random in the forest. Squirrels built nests only in mixed-hardwood forest. Overall, this introduced species exhibited nest site selection behavior similar to other tree squirrels, and appears capable of continued spread despite the initial site of introduction on an oceanic island. Knowledge obtained from this research is being used by managers and applied to an eradication program to remove this invasive species from Biscayne National Park.
    • Ecological Design Principles For A Mixed-Use Development In Tucson, Arizona

      D'Arcy, Gerard (The University of Arizona., 2006)
      This report explores the process of designing sustainable mixed-use communities in Tucson, Arizona. It is intended as a primer for the ecological design of large buildings in a hot/arid climate region. It combines and expands on the concepts and relationships between sustainability and mixed-use development in Tucson and provides this information in order to elevate the discussion on these issues as directly related to future development of the Tucson urban core. A particular site in downtown Tucson is subject to a design proposal that responds to the city’s desire for this type of development while working in line with the current city models and ordinances. Furthermore, the final design attempts to meet the objectives for optimizing opportunities regarding the implementation of ecological design principles such as natural ventilation, natural day lighting and water conservation. The major motivation behind the following report is two fold; It illustrates the environmental condition that exists in Tucson today (physical and political) and outlines an approach to design that seeks to ensure that future generations enjoy continued access to the world’s natural resources.
    • Ecological distribution of the mammalian fauna of the Desert Biology Station Area

      Drabek, Charles Martin, 1942- (The University of Arizona., 1967)
    • An ecological study of the vertebrate animals of the mesquite forest

      Arnold, Lee Weight, 1914- (The University of Arizona., 1940)
    • An ecological survey of a mesquite bosque

      Gavin, Thomas A. (Thomas Alan) (The University of Arizona., 1973)
    • An ecological survey of the Three-Bar Game Management Unit located near Roosevelt, Arizona

      Dickerman, Robert William, 1926- (The University of Arizona., 1954)
    • Ecology and conservation of the twin-spotted rattlesnake, Crotalus pricei

      Schwalbe, Cecil R.; Prival, David Benjamin (The University of Arizona., 2000)
      Although twin-spotted rattlesnakes (Crotalus pricei ) were first identified more than a century ago, little has been published about the ecology of this species and no information has been available regarding population characteristics. During 1997--99, I captured, measured, and marked 117 C. pricei in the Chiricahua Mountains to address this need for information. Lizards constituted the bulk of C. pricei prey, but their diet also included mammals, birds, and snakes. Mating and parturition were concentrated in August and early September. Movement patterns varied dramatically from year to year, as males moved substantially farther during the 1998 monsoon season (July--September) than in 1997. Crotalus pricei are sometimes collected illegally for the pet trade. About 90 people may have hunted for C. pricei at a well-known site during 1997--98. On average, snakes at this site were 38.1 mm smaller than snakes at other sites, an observation that could be attributed to collecting pressure.