Mobility and the Metropolis: How Communities Factor Into Economic Mobility

This report shows that neighborhoods play an important role in determining a family's prospects of moving up the economic ladder. Metropolitan areas where the wealthy and poor live apart have lower mobility than areas where residents are more economically integrated

OPTIC FLOW BASED STATION-KEEPING AND WIND REJECTION FOR SMALL FLYING VEHICLES

Optic flow and Wide Field Integration (WFI) have shown potential for application to autonomous navigation of Unmanned Air Vehicles (UAVs). In this study the application of these same methods to other tasks, namely station-keeping and wind rejection, is examined. Theory surrounding optic flow, WFI and wind gust modeling is examined to provide a theoretical background. A controller based on a H∞ bounded formulation of the well known Linear Quadratic Regulator in designed to both mitigate wind disturbances and station-keep. The performance of this controller is assessed via simulation to determine both performance and trade-offs in implementation such as the method for optic flow calculation. Furthermore, flight tests are performed to examine the real world effectiveness of the controller. Finally, conclusions about potential improvement to implementation are drawn

Global stability, or instability, of positive equilibria of p-Laplacian boundary value problems with p-convex nonlinearities

We consider the parabolic, initial value problem vt = Δp(v) + λg(x, v)φp(v), in Ω x (0,∞), v = 0, in ∂Ω x (0,∞), (IVP) v = v0 > 0, in Ω x {0}, where Ω is a bounded domain in RN , for some integer N > 1, with smooth boundary ∂Ω, φp(s) := |s|p−1 sgn s , s ∈ R , and Δp denotes the p -Laplacian, with p > max{2,N} , v0 ∈ C0(Ω) , and λ > 0 . The function g : Ω x [0,∞) → (0,∞) is C0 and, for each x ∈ Ω , the function g(x, ·) : [0,∞) → (0,∞) is Lipschitz continuous and strictly increasing. Clearly, (IVP) has the trivial solution v ≡ 0 , for all λ > 0 . In addition, there exists 0 < λmin(g) < λmax(g) such that: • if λ ∈/ (λmin(g),λmax(g)) then (IVP) has no non-trivial, positive equilibrium; • there exists a closed, connected set of positive equilibria bifurcating from (λmax(g), 0) and ‘meeting infinity’ at λ = λmin(g) . We prove the following results on the positive solutions of (IVP): • if 0 < λ < λmin(g) then the trivial solution is globally asymptotically stable; • if λmin(g) < λ < λmax(g) then the trivial solution is locally asymptotically stable and all non-trivial, positive equilibria are unstable; • if λmax(g) < λ then any non-trivial solution blows up in finite time

Obstacles on the path: An exposition of the experience of car-free living

The contemporary focus by local and central government on the promotion of sustainable transport options has highlighted the need for commuting to move away from the current dependence on private cars to more public and active (walking and cycling) modes of transport. Given the prominence of the motor car in personal transport options however, choosing to live car-free in this car dependent culture appears at first glance to be an irrational choice. This research explores the lived experiences of a group of Hamilton residents who have made such a choice. Using a grounded theory approach, the thesis presents the results of interviews with nine car-free Hamilton residents who shared their personal transport stories, which include their childhood experiences, but focus on their current everyday practices and experiences. Through semi-structured interviews, the costs and benefits of a car-free lifestyle are articulated and analysed. Their motivations for choosing to forgo cars and their solutions for overcoming potential barriers to car-free living are also reported and explored. The collected data generated a range of themes which are presented in three chapters, each covering a specific aspect of the participants’ stories. The first group of themes relate to the public sphere, the second to the private realm and the final group emanates from specific elements of car-free living that the thesis sought to clarify through the participants’ stories. The key finding is that living car-free within Hamilton City is viewed by the participants as a well reasoned and eminently sensible choice, which produces multiple benefits. In addition to their reduced environmental footprints, the participants value the social interaction associated with active and public transport. Their consensus is that they are healthier, wealthier and more involved members of the community. The most problematic areas of living without a car were associated with recreational and social activities, which often do not coincide with public transport schedules or involve distances too great for active transport. The benefits far outweigh any disadvantages however, and ultimately, this thesis concludes that a motor car is not necessary for the everyday activities of urban living in Hamilton and any associated inconveniences are not as insurmountable as generally imagined

Intermittent hypercapnia induces long-lasting ventilatory plasticity to enhance CO₂ responsiveness to overcome dysfunction

Thesis (Ph.D.) University of Alaska Fairbanks, 2014The ability of the brain to detect (central CO₂ chemosensitivity) and respond to (central CO₂ chemoresponsiveness) changes in tissue CO₂/pH, is a homeostatic process essential for mammalian life. Dysfunction of the serotonin (5-HT) mechanisms compromises ventilator CO₂ chemosensitivity/responsiveness and may enhance vulnerability to pathologies such as the Sudden Infant Death Syndrome (SIDS). The laboratory of Dr. Michael Harris has shown medullary raphe' contributions to central chemosensitivity involving both 5-HT- and y-aminobutyric acid (GABA)-mediated mechanisms. I tested the hypothesis that postnatal exposure to mild intermittent hypercapnia (IHc) induces respiratory plasticity, due in part to strengthening of bicuculline- and saclofen-sensitive mechanisms (GABAA and GABAB receptor antagonists respectively). Rats were exposed to IHc-pretreatment (8 cycles of 5 % CO₂) for 5 days beginning at postnatal day 12 (P12). I subsequently assessed CO₂ responsiveness using an in situ perfused brainstem preparation. Hypercapnic responses were determined with and without pharmacological manipulation. In addition, IHc-pretreatment effectiveness was tested for its ability to overcome dysfunction in the CO₂ responsiveness induced by a dietary tryptophan restriction. This dysfunctional CO₂ responsiveness has been suggested to arise from a chronic, partial 5-HT reduction imparted by the dietary restriction. Results show IHc-pretreatment induced plasticity sufficient for CO₂ responsiveness despite removal of otherwise critical ketanserin-sensitive mechanisms. CO₂ responsiveness following IHc-pretreatment was absent if ketanserin was combined with bicuculline and saclofen, indicating that the plasticity was dependent upon bicuculline- and saclofen-sensitive mechanisms. IHc-induced plasticity was also capable of overcoming the ventilatory defects associated with maternal dietary restriction. Duration of IHc-induced plasticity was also investigated and found to last far into life (up to P65). Furthermore, I performed experiments to investigate if IHc-induced plasticity was more robust at a specific developmental period. No such critical period was identified as IHc-pretreatment induced robust respiratory plasticity when administered at all developmental periods tested (P12-16, P21-25 and P36-40). I propose that IHc-induced plasticity may be able to reduce the severity of reflex dysfunctions underlying pathologies such as SIDS

Displaying Race at the Jamestown Ter-Centennial Exposition

World expositions of the nineteenth and early twentieth century often displayed the latest anthropological, ethnological, biological, and technological research on race and ethnicity, promoting the view that whites were superior to all other peoples. The Jamestown Ter-Centennial Exposition of 1907, held in Norfolk, Virginia to commemorate the three-hundred anniversary of the founding of the Jamestown settlement and its contribution to the building of the United States, offers an opportunity to examine American perspectives on whiteness, race, and society. First, the Jamestown Exposition offered a glimpse into the historical memory of white America, especially the influential citizens that comprised the controlling entity behind the event, the Jamestown Exposition Company, as they determined how to commemorate the founding of Jamestown, United States history, and race and ethnicity. Second, the event offered a view of race relations in the United States in the first decade of the twentieth century, as several components of the exposition displayed information about minorities and persons of color in the United States and around the world, placing them in the dominant, white narrative offered in the records, histories, souvenirs, and exhibits of the event. Third, the Jamestown Exposition offered a window into the growing movement to advance the rights and status of African Americans, as evidenced by the efforts of the Negro Development and Exposition Company (N.D.E.C.), which used its building and exhibits to provide a more accurate and less biased history of African Americans and promote the view that they were industrious, competent, and worthy of equal status with white Americans. The Jamestown Exposition reflected the dominant narrative of race in the United States, created and controlled by white Americans and promoting the view that whites were superior. While exhibitions included commemorations of American Indians and displayed various peoples such as Filipinos, the central focus of this thesis is the African American attempt to take control of the display of their race rather than allow the Jamestown Exposition Company and white Americans to perpetuate their racist views. African Americans who participated in the Jamestown Exposition sought to overcome the overwhelming racism from white Americans by taking matters into their own hands and illustrating their worth and equality through education exhibits. Ultimately, the narrative of white superiority, scientific racism, and nonwhite exploitation dominated the event, included in the exhibits, guides, histories, and souvenirs of the Jamestown Ter-Centennial Exposition

Linear and nonlinear, second-order problems with Sturm-Liouville-type, multi-point boundary conditions

We consider the nonlinear equation $$-u'' = f(u) + h , \quad \text{on} \quad (-1,1),$$ where $f : {\mathbb R} \to {\mathbb R}$ and $h : [-1,1] \to {\mathbb R}$ are continuous, together with general Sturm-Liouville type, multi-point boundary conditions at $\pm 1$. We will obtain existence of solutions of this boundary value problem under certain `nonresonance' conditions, and also Rabinowitz-type global bifurcation results, which yield nodal solutions of the problem. These results rely on the spectral properties of the eigenvalue problem consisting of the equation $$-u'' = \lambda u, \quad \text{on} \quad (-1,1),$$ together with the multi-point boundary conditions. In a previous paper it was shown that, under certain `optimal' conditions, the basic spectral properties of this eigenvalue problem are similar to those of the standard Sturm-Liouville problem with single-point boundary conditions. In particular, for each integer $k \geq 0$ there exists a unique, simple eigenvalue $\lambda_k$, whose eigenfunctions have `oscillation count' equal to $k$, where the `oscillation count' was defined in terms of a complicated Pr\"ufer angle construction. Unfortunately, it seems to be difficult to apply the Pr\"ufer angle construction to the nonlinear problem. Accordingly, in this paper we use alternative, non-optimal, oscillation counting methods to obtain the required spectral properties of the linear problem, and these are then applied to the nonlinear problem to yield the results mentioned above