Showing items related by title, author, creator and subject.

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  Satellite patches, patch expansion, and doubling time as decision metrics for invasion control: Pennisetum ciliare expansion in southwestern Arizona

  Weston, Jaron D.; McClaran, Mitchel P.; Whittle, Richard K.; Black, Christian W.; Fehmi, Jeffrey S.; Univ Arizona, Sch Nat Resources & Environm (CAMBRIDGE UNIV PRESS, 2019-03)

  Essential variables to consider for an efficient control strategy for invasive plants include dispersion pattern (i.e., satellite or invasion front) and patch expansion rate. These variables were demonstrated for buffelgrass [Pennisetum ciliare (L.) Link], a C-4 perennial grass introduced from Africa, which has invaded broadly around the world. The study site was along a roadway in southern Arizona (USA). The P. ciliare plant distributions show the pattern of clumping associated with the satellite (nascent foci) colonization pattern (average nearest neighbor test, z-score -47.2, P <0.01). The distance between patches ranged from 0.743 to 12.8 km, with an average distance between patches of 5.6 km. Median patch expansion rate was 271% over the 3-yr monitoring period versus 136% found in other studies of established P. ciliare patches. Targeting P. ciliare satellite patches as a control strategy may exponentially reduce the areal doubling time, while targeting the largest patches may have less effect on the invasion speed.
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  Criminal alienation: Arizona prison expansion, 1993-2003

  Joseph, Miranda; Hammer-Tomizuka, Zoe (The University of Arizona., 2004)

  Criminal Alienation: Arizona Prison Expansion 1993-2003 argues that border militarization and the criminalization of Latino immigrants has increasingly driven Arizona prison expansion between 1993 and 2003. It identifies four policy shifts that have reversed decarceration trends in the state's prison growth over this ten year period, resulting in the emergence of an expanding "border-prison system". The project both enacts and argues in favor of a politically participatory cultural studies methodology, guided by a post-structuralist Marxist theoretical approach stressing interdependencies between political economic processes and subject formation. Criminal Alienation offers an intervention in the field of cultural studies, arguing for the foregrounding of state repression in the study of capital and social power relations. It also contributes to the field of prison studies with an analysis of the role of U.S. immigration policy, narratives of immigration, and the social production of "criminal alien" and "consenting citizen" identities in the expansion of the contemporary prison industrial complex. The case studies in Criminal Alienation center on narratives and practices surrounding the emergence of immigrant-only prisons, both state and federal, in Arizona. The project analyzes a variety of repressive state practices and narratives, identifying the ways in which the effects of state coercion are manifested in the social reproduction and reiteration of the border-prison system as well as the ways that these effects shape networked abolitionists struggles in and beyond the region. Finally, Criminal Alienation identifies the Arizona-Sonora border region as a significant front in the struggle for prison abolition by delineating historical and contemporary linkages between abolitionist resistance strategies and practices and the emergence of collaborative, socially transformative visions of community-based development, led by the communities most adversely affected by coercive state practices.
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  Low-energy collision phenomena in free jet expansions: Molecular relaxation theory and ion-molecule rate studies.

  Smith, Mark A.; Randeniya, Lakshman Kumar.; Bernath, Peter F.; Salzman, William R.; Fernando, Quintus; Buckner, Steven W. (The University of Arizona., 1990)

  Theoretical and experimental development of a new kinetic method to measure the rate coefficients of ion-molecule reactions occurring in free jet expansions below 20K is presented. The method is successfully used to determine the temperature dependences of numerous bimolecular and termolecular ion-molecule reactions over the temperature range of 0.5-20K. A new theoretical method based on the generalized Boltzmann equation is developed to calculate macroscopic flow properties of pure molecular supersonic flows. The variation of the different temperature components, hydrodynamic speed and density of the free jet as a function of distance is presented assuming a Maxwellian anisotropic distribution function. This theory facilitates the kinetic analysis and the assignment of temperatures to the chemical reactions occurring in jets. Using the Boltzmann equation, the flow properties of a mixed atomic free jet expansion are also analyzed. The method is more general than previous treatments which assume a vanishingly small mole fraction for one component of the mixture. The presence of velocity slip arising from the difference in hydrodynamic speeds of the two components complicates this treatment. Expressions for the calculation of flow properties for an atomic mixture with an arbitrary composition are presented. Temperature dependences of the termolecular association rate coefficients for the reactions of, N₂⁺ + 2N₂, O₂⁺ + 2O₂ and NO⁺ + 2NO over the temperature range of 3-15K are presented. The results are discussed in the light of statistical phase space theory. For the reactions of N₂⁺ + 2N₂ and O₂⁺ + 2O₂ excellent agreement between theory and experiment is obtained. The kinetic analysis of NO⁺ + 2NO is complicated due to the competing charge transfer reaction. The observed temperature dependence for this reaction does not agree with the predictions of the statistical theory. The ternary association rate coefficients for the reaction, Ar⁺ + 2Ar, show a strong temperature dependence at very low temperatures (0.5-2.5K). Current statistical formulations cannot predict this temperature dependence and a comprehensive model for this reaction mechanism has yet to be developed. Three distinct temperature dependences are observed for the bimolecular reactions of N₂⁺ with CH₄, O₂ and n-H₂ at temperatures below 15K. Speculations are made regarding the interaction potential energy surfaces that may lead to the observed behaviors.