Letter from the Chair

https://deepblue.lib.umich.edu/bitstream/2027.42/143821/1/A_12 Letter from the Chair.pd

Rare Earth Element Distributions in Forest Soils Across Bedrock Gradients in New Hampshire and Vermont

Within Earth surface systems, forests factor critically in carbon cycling and sequestration and accordingly play an important role in many climate change mitigation strategies. Predictive models of carbon storage require assessments of carbon storage as well as nutrient cycling, which, in turn, has long-term impacts on carbon storage. Nutrient allocations affect tree biomass, leaf growth, stem density, and biodiversity. Yet, bedrock contributions to nutrient allocations are not routinely quantified, even though bedrock compositions can influence soil types, soil pH, and tree species within forest. Here, I expand on previously developed approaches to conduct a comparative study between eight sites across New Hampshire and Vermont with soils developed over varied bedrock lithologies. I investigate if rare earth elements (REEs) are useful proxies for chemical weathering of soils and bedrock and Ca, Mg allocations in soil and foliage samples. As has been found in previous studies, shallow soils and foliage samples were less enriched with REEs than those samples from the deepest soil depths. While Mg and REE allocations are not strongly associated with each other, links between highly abundant REEs and nutrients showed a promising correlation between Ca depletions to enhance the understanding of how tree species may behave in a Ca-depleted environment

Contracting Around Finality: Transforming Price v. Neal from Dictate to Default

Arguably the most important and problematic area within the entire field of negotiable instruments law is the law relating to forgery, especially the allocation of losses that result from forgery. Forgery is central to negotiable instrument law because a signature typically authenticates the orders and promises to pay on which the entire system is based. Unfortunately, forgery continues to cause substantial losses to American banks and the national economy. Despite the significance of this problem, many of the legal doctrines governing forgery loss allocation remain quite problematic, even after nearly three centuries of development. To combat the problem of negotiable instrument fraud, this Article argues that the time-honored doctrine of finality, as embodied in the case of Price v. Neal and § 3-418(c) of the Revised Uniform Commercial Code (RUCC) should be transformed from a rigid, per se dictate into a default rule. This transformation would constitute a significant change in Anglo-American commercial paper law. The goal of this transformation is to allow presenters of negotiable drafts and payor banks to better allocate the losses of forgery to the party who is most willing to bear that burden. This ability to allocate losses, in turn, is designed to reduce the costs of forgery and improve the efficiency of the American commercial paper system

Metropolitan Accessibility and Transportation Sustainability: Comparative Indicators for Policy Reform

Accessibility is most commonly studied and measured within the context of a single metropolitan region. By contrast, this study applies metrics of accessibility (for work, non-work, by auto and transit) that incorporate both mobility and proximity to 38 of the largest 50 U.S. metropolitan areas. This cross-sectional analysis allows both intermetropolitan comparison (of accessibility overall and of the equity of its distribution) and assessment of the determinants of metropolitan accessibility. The two components of accessibility analyzed here—mobility and proximity—exist in tension with each other: places with rapid surface travel are usually places where origins and destinations are far apart; places with many origins and destinations in close proximity are places where travel tends to be slow. For this reason, it is not apparent which urban forms offers greater accessibility: those with spread-out land uses and more rapid travel, or more compact arrangements in which travel is slower. There are good theoretical reasons to expect that surface travel speeds are all-important in determining accessibility outcomes and that anything that interferes with surface travel speeds—including denser metropolitan development—might degrade accessibility. Empirical results presented here suggest the opposite: more compact metropolitan regions offer greater auto accessibility even if their travel speeds are somewhat slower. In other words, the proximity effect of density dominates any associated degradation in travel speeds. This suggests that reform of policies that spur low-density, auto-oriented development can yield transportation benefits in terms of increased metropolitan accessibility. The report also develops indicators for assessing the equity of the distribution of accessibility between individuals within a region. Indicators developed here capture accessibility distributions across dimensions of income, race, and car ownership. Even with a given accessibility distribution by auto and by transit, the equity of the accessibility distribution also depends on the location of carless households within a metropolitan region; indicators are also developed to capture this effect.EPA Agreement Number: RD-833334901-0 and FHWA Cooperative Agreement Number: DTFH61-07-H-00037https://deepblue.lib.umich.edu/bitstream/2027.42/147459/1/MetropolitanAccessibilityTransportationSustainability.pdfDescription of MetropolitanAccessibilityTransportationSustainability.pdf : Technical repor

How much are built environments changing, and where?: Patterns of change by neighborhood sociodemographic characteristics across seven U.S. metropolitan areas

Investments in neighborhood built environments could increase physical activity and overall health. Disproportionate distribution of these changes in advantaged neighborhoods could inflate health disparities. Little information exists on where changes are occurring. This paper aims to 1) identify changes in the built environment in neighborhoods and 2) investigate associations between high levels of change and sociodemographic characteristics. Using Geographic Information Systems, neighborhood land-use, local destinations (for walking, social engagement, and physical activity), and sociodemographics were characterized in 2000 and 2010 for seven U.S. cities. Linear and change on change models estimated associations of built environment changes with baseline (2000) and change (2010–2000) in sociodemographics. Spatial patterns were assessed using Global Moran’s I to measure overall clustering of change and Local Moran’s I to identify statistically significant clusters of high increases surrounded by high increases (HH). Sociodemographic characteristics were compared between HH cluster and other tracts using Analysis of Variance (ANOVA). We observed small land-use changes but increases in the destination types. Greater increases in destinations were associated with higher percentage non-Hispanic whites, percentage households with no vehicle, and median household income. Associations were present for both baseline sociodemographics and changes over time. Greater increases in destinations were associated with lower baseline percentage over 65 but higher increases in percentage over 65 between 2000 and 2010. Global Moran’s indicated changes were spatially clustered. HH cluster tracts started with a higher percentage non-Hispanic whites and higher percentage of households without vehicles. Between 2000 and 2010, HH cluster tracts experienced increases in percent non-Hispanic white, greater increases in median household income, and larger decreases in percent of households without a vehicle. Changes in the built environment are occurring in neighborhoods across a diverse set of U.S. metropolitan areas, but are patterned such that they may lead to increased health disparities over time

Transport geography: perspectives upon entering an accomplished research sub-discipline

No abstract available

Direct precipitation of siderite in ferruginous environments

Siderite (FeCO3) is often assumed to precipitate from dissimilatory reduction of Fe-(oxyhydr)oxides, but geochemical and mineralogical analyses from ferruginous (anoxic, Fe-rich) Canyon Lake, USA, suggest Fe-carbonate represents a direct early precipitate unrelated to substantial oxide burial. X-ray absorption near edge structure (XANES) spectroscopy of sediment trap materials and an anoxic sediment core indicated a mixture of Fe(II) and Fe(III) in water column particulates and ferruginous surface sediments, while all Mn phases were reduced. About 60 cm below the sediment–water interface, Fe-Mn carbonates were detected by X-ray diffraction and XANES, while Fe extended X-ray absorption fine structure (EXAFS) spectra were best fit with combinations of a biogenic Fe-oxyhydroxide (“Bio Fe”), greigite, and siderite. Sediment Fe speciation indicates a large pool of reduced Fe with a minor component of oxides. Although we found no evidence of significant carbonate phases above or below the 60 cm horizon, equilibrium modelling indicates siderite supersaturation throughout surface sediment porewater, with pH as the primary control on supersaturation. We conclude that delivery of wildfire ash to sediments increased pH, initiating siderite precipitation from ferruginous porewater.This article is published as Grengs, A., G. Ledesma, Y. Xiong, S. Katsev, S. W. Poulton, E. D. Swanner, and C. Wittkop. "Direct precipitation of siderite in ferruginous environments." 30 (2024): 1-6. https://doi.org/10.7185/geochemlet.2414. © 2024 The Authors. Under Creative Commons License CC BY-NC-ND 4.0

Advancing Equity Planning Now

What can planners do to restore equity to their craft? Drawing upon the perspectives of a diverse group of planning experts, Advancing Equity Planning Now places the concepts of fairness and equal access squarely in the center of planning research and practice. Editors Norman Krumholz and Kathryn Wertheim Hexter provide essential resources for city leaders and planners, as well as for students and others, interested in shaping the built environment for a more just world.Advancing Equity Planning Now remind us that equity has always been an integral consideration in the planning profession. The historic roots of that ethical commitment go back more than a century. Yet a trend of growing inequality in America, as well as other recent socio-economic changes that divide the wealthiest from the middle and working classes, challenge the notion that a rising economic tide lifts all boats. When planning becomes mere place-making for elites, urban and regional planners need to return to the fundamentals of their profession. Although they have not always done so, planners are well-positioned to advocate for greater equity in public policies that address the multiple objectives of urban planning including housing, transportation, economic development, and the removal of noxious land uses in neighborhoods

Evaluating a primary carbonate pathway for manganese enrichments in reducing environments

Most manganese (Mn) enrichments in the sedimentary rock record are hosted in carbonate minerals, which are assumed to have formed by diagenetic reduction of precursor Mn-oxides, and are considered diagnostic of strongly oxidizing conditions. Here we explore an alternative model where Mn-carbonates form in redox-stratified water columns linked to calcium carbonate dissolution. In ferruginous Brownie Lake in Minnesota, USA, we document Mn-carbonates as an HCl-extractable phase present in sediment traps and in reducing portions of the water column. Mn-carbonate becomes supersaturated in the Brownie Lake chemocline where dissolved oxygen concentrations fall below 5 μM, and Mn-oxide reduction increases the dissolved Mn concentration. Supersaturation is enhanced when calcite originating from surface waters dissolves in more acidic waters at the chemocline. In the same zone, sulfate reduction and microaerobic methane oxidation add dissolved inorganic carbon (DIC) with negative . These observations demonstrate that sedimentary Mn enrichments may 1) develop from primary carbonate phases, and 2) can occur in environments with dissolved oxygen concentrations 200 μM), and where Mn and Fe are partitioned by S cycling, photoferrotrophy, or microaerophilic Fe-oxidation. A shallow lysocline enhances Mn-carbonate production by providing additional DIC and nucleation sites for crystal growth. This carbonate model for Mn-enrichments is expected to be viable in both euxinic and ferruginous environments, and provides a more nuanced view of the relationships between Mn and carbon cycling, with applications throughout the rock record