Three Essays in Urban Policy

The papers in this dissertation share a common theme of measuring policy effects in urban markets. Though focusing on different outcomes – access to rental housing, property values, and school enrollments – the desire to understand how policy influences the composition of an urban ecosystem provides the link. A particular emphasis is placed on housing, because housing is simultaneously and a basic requirement for humans to thrive and the primary source of most local finance in the U.S. When policy affects housing, be it directly or indirectly, it can have important and far-reaching consequences. Understanding the intended and unintended consequences of urban policy is thus central to this dissertation research and my future research agenda. Chapter 1 offers the first evidence of differential treatment occurring across the broad spectrum of racial and protected classes covered under the law. Employing a fully randomized correspondence audit design and a sample of more than 9,500 online housing advertisements, the study offers insight about which protected groups experience the most/least favorable treatment when searching for housing. This study employs a new signaling strategy in order to provide the first evidence of how landlord treatment of rental housing applicants varies across the spectrum of protected classes. The findings suggest rental-housing providers have preferences about tenants and make decisions based on signals communicated in inquiry emails from potential applicants. The findings also suggest differential treatment is generally consistent with theory of agent-based statistical discrimination. Chapter 2 presents an experiment designed to influence rental agent behavior to increase equal treatment in rental housing. The purpose is to test whether property owners and rental agents will change their behavior in response to being informed about their obligations under fair housing law. The project thus conducts a randomized experiment employs a correspondence housing audit methodology to measure the impact, representing the first time in which the audit methodology is employed to measure the effect of a randomized experiment. The results of the experiment consistently suggest the group of landlords who received information about fair housing law responded at a higher rate than did those who did not receive the treatment email. The primary contribution of this paper, then, is to demonstrate a unique opportunity to test policy interventions aimed at reducing discrimination in a real housing market and at a very low cost. My hope is that the method will be modified and expanded by fair housing agencies, advocates, and other institutions to test and implement policy interventions in hopes of reducing barriers to access in housing. Chapter 3 examines the impact of a place-based program on urban property values and school enrolments. A recent trend in place-based policy targets college attainment by offering tuition scholarships for qualified students in under-resourced public schools. In an era of rising college costs, these programs represent a potentially large financial benefit to those living within the attendance zones of qualifying schools. The benefit of such programs should be capitalized into local property values and school district enrolment, as programs are directly linked to attendance zones. This research thus examines the impact a large scholarship program, Say Yes to Education, has on school enrolments and property values in upstate New York. Examining district enrollment from 2000 through 2014, the analysis finds that after years of steady declines in enrollments, both Syracuse and Buffalo saw enrollment increases that coincide with the adoption of the Say Yes to Education program. These increases occurred at different points in time in each city. The housing values results provide some evidence that increases in housing prices accompanied the adoption of Say Yes in Syracuse, but not in Buffalo. These results are consistent with findings that enrolment growth in Buffalo may have been driven by students who would otherwise have attended private schools, while enrollment growth in Syracuse may have been driven by students who would otherwise have attended school in the surrounding suburbs. Combined with the enrolment effects, the analysis suggests that the ability of place-based scholarships to attract residents into a central city is likely to depend on both the specific provisions of the program and the context in which it is implemented

Mechanical properties of borothermally synthesized ZrB2

Mechanical properties of borothermally synthesized, highly pure ZrB2 were tested at room and elevated temperatures. Commercially available ZrB2 powder typically contains 1 to 4 wt % hafnium which has been shown to lower thermal properties of dense ZrB2 ceramics. Further, commercial grade ZrB2 contains other impurities (0.6 wt% O, 0.11 wt% N, 0.04 wt% Fe and others) which are also known to decrease its high-temperature mechanical strength. Purer grades of zirconia and boron powders, containing \u3c 75 ppm hafnium and \u3c0.5 wt% of other metal impurities, were reacted to produce ZrB2 for room and elevated temperature mechanical property studies. The zirconia and boron powders were reacted at 1000°C in a graphite vacuum furnace for two hours. The synthesized ZrB2 powder was then rinsed with methanol to remove boria from its surfaces, sieved with a #45 mesh, and hot pressed to near full density with 32 MPa applied pressure in a flowing argon atmosphere at 2100°C. The hot pressed billets were machined to ASTM standard test bars with the flexure surface polished to 1 um. Young’s modulus, Vickers Hardness, fracture toughness, and four-point bend strength were measured, and the results will be discussed

Room-Temperature Mechanical Properties of a High-Entropy Diboride

The mechanical properties of a (Hf,Mo,Nb,Ta,W,Zr)B2 high-entropy ceramic were measured at room temperature. A two-step synthesis process was utilized to produce the (Hf,Mo,Nb,Ta,W,Zr)B2 ceramics. The process consisted of a boro/carbothermal reduction reaction followed by solid solution formation and densification through spark plasma sintering. Nominally, phase pure (Hf,Mo,Nb,Ta,W,Zr)B2 was sintered to near full density (8.98 g/cm3) at 2000°C. The mean grain size was 6 ± 2 µm with a maximum grain size of 17 µm. Flexural strength was 528 ± 53 MPa, Young\u27s modulus was 520 ± 12 GPa, fracture toughness was 3.9 ± 1.2 MPa·m1/2, and hardness (HV0.2) was 33.1 ± 1.1 GPa. A Griffith-type analysis determined the strength limiting flaw to be the largest grains in the microstructure. This is one of the first reports of a variety of mechanical properties of a six-component high-entropy diboride

Analysing the impact of living in a rural setting on the presentation and outcome of colorectal cancer : A prospective single centre observational study

Peer reviewedPostprin

Challenges in the Search for Perchlorate and Other Hydrated Minerals With 2.1-μm Absorptions on Mars

A previously unidentified artifact has been found in Compact Reconnaissance Imaging Spectrometer for Mars targeted I/F data. It exists in a small fraction (<0.05%) of pixels within 90% of images investigated and occurs in regions of high spectral/spatial variance. This artifact mimics real mineral absorptions in width and depth and occurs most often at 1.9 and 2.1 μm, thus interfering in the search for some mineral phases, including alunite, kieserite, serpentine, and perchlorate. A filtering step in the data processing pipeline, between radiance and I/F versions of the data, convolves narrow artifacts (“spikes”) with real atmospheric absorptions in these wavelength regions to create spurious absorption-like features. The majority of previous orbital detections of alunite, kieserite, and serpentine we investigated can be confirmed using radiance and raw data, but few to none of the perchlorate detections reported in published literature remain robust over the 1.0- to 2.65-μm wavelength range

Mineralogy of the MSL Curiosity landing site in Gale crater as observed by MRO/CRISM

Orbital data acquired by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) and High Resolution Imaging Science Experiment instruments on the Mars Reconnaissance Orbiter (MRO) provide a synoptic view of compositional stratigraphy on the floor of Gale crater surrounding the area where the Mars Science Laboratory (MSL) Curiosity landed. Fractured, light-toned material exhibits a 2.2 µm absorption consistent with enrichment in hydroxylated silica. This material may be distal sediment from the Peace Vallis fan, with cement and fracture fill containing the silica. This unit is overlain by more basaltic material, which has 1 µm and 2 µm absorptions due to pyroxene that are typical of Martian basaltic materials. Both materials are partially obscured by aeolian dust and basaltic sand. Dunes to the southeast exhibit differences in mafic mineral signatures, with barchan dunes enhanced in olivine relative to pyroxene-containing longitudinal dunes. This compositional difference may be related to aeolian grain sorting

Orbital evidence for more widespread carbonate-bearing rocks on Mars

Carbonates are key minerals for understanding ancient Martian environments because they are indicators of potentially habitable, neutral-to-alkaline water and may be an important reservoir for paleoatmospheric CO_2. Previous remote sensing studies have identified mostly Mg-rich carbonates, both in Martian dust and in a Late Noachian rock unit circumferential to the Isidis basin. Here we report evidence for older Fe- and/or Ca-rich carbonates exposed from the subsurface by impact craters and troughs. These carbonates are found in and around the Huygens basin northwest of Hellas, in western Noachis Terra between the Argyre basin and Valles Marineris, and in other isolated locations spread widely across the planet. In all cases they cooccur with or near phyllosilicates, and in Huygens basin specifically they occupy layered rocks exhumed from up to ~5 km depth. We discuss factors that might explain their observed regional distribution, arguments for why carbonates may be even more widespread in Noachian materials than presently appreciated and what could be gained by targeting these carbonates for further study with future orbital or landed missions to Mars