• An Advanced Protocol-Driven Transition from Parenteral Prostanoids to Inhaled Trepostinil in Pulmonary Arterial Hypertension

      Oudiz, Ronald; Agarwal, Manyoo; Rischard, Franz; De Marco, Teresa; Univ Arizona, Coll Med, Dept Pulm Crit Care & Sleep Med (UNIV CHICAGO PRESS, 2016-12)
      Patients with pulmonary arterial hypertension (PAH) often require parenteral prostanoids to improve symptoms and signs of PAH. Complications of parenteral prostanoids-such as catheter-related infections and intolerable adverse effects-may develop, prompting transition to inhaled prostanoids. We report a prospective, protocol-driven transition from parenteral prostanoids to inhaled prostanoids with monitoring of exercise gas exchange and acute hemodynamics. Three PAH centers recruited patients transitioning from parenteral prostanoids to inhaled trepostinil. Rigid inclusion criteria were used, including parenteral prostanoid dose < 30 ng/kg/min, New York Heart Association functional class (FC) < 3, and pulmonary vascular resistance (PVR) < 6 Wood units. Of the 9 patients meeting initial inclusion criteria, 3 were excluded. In the remaining patients, the parenteral prostanoid was reduced and the inhaled prostanoid was increased over 24-36 hours with continuous hemodynamic monitoring. Exercise capacity and FC were measured at baseline and weeks 1, 4, and 12. All patients were successfully weaned from parenteral prostanoids. An acute PVR decrease was seen with most inhaled prostanoid doses, but PVR varied throughout the transition. Patients tolerated inhaled prostanoids for 9-12 breaths 4 times a day with no treatment-limiting adverse events. At week 12, FC was unchanged, and all patients continued to receive inhaled prostanoids without serious adverse events or additional PAH therapy. In 5 of 6 patients, 6-minute walk distance and peak VO2 were within 10% of baseline. Using a strict transition protocol and rigid patient selection criteria, the parenteral prostanoid to inhaled prostanoid transition appeared safe and well tolerated and did not result in clinical deterioration over 12 weeks. Hemodynamic variability noted acutely during transition in our study did not adversely affect successful transition.
    • Affiliation Bias in Arbitration: An Experimental Approach

      Puig, Sergio; Strezhnev, Anton; Univ Arizona, James E Rogers Coll Law (UNIV CHICAGO PRESS, 2017-06)
      A characteristic feature of arbitration, a growing form of legal adjudication, is that each disputing party appoints an arbitrator. Commentators, however, suggest that party-appointed arbitrators tend to be biased in favor of their appointers. Evaluating this claim from data on historical disputes is problematic because of nonrandom selection of arbitrators. Here we use a novel experimental approach to estimate the causal effect of the appointing party. Using survey experiments with arbitration experts around the world, we show that professional arbitrators suffer from affiliation effectsa cognitive predisposition to favor the appointing party. At a methodological level, we offer a solution to the problem of measuring this effect when credible observational designs are lacking.
    • Atypical Flowers Can Be as Profitable as Typical Hummingbird Flowers

      Waser, Nickolas M.; CaraDonna, Paul J.; Price, Mary V.; Univ Arizona, Sch Nat Resources & Environm (UNIV CHICAGO PRESS, 2018-11)
      In western North America, hummingbirds can be observed systematically visiting flowers that lack the typical reddish color, tubular morphology, and dilute nectar of hummingbird flowers. Curious about this behavior, we asked whether these atypical flowers are energetically profitable for hummingbirds. Our field measurements of nectar content and hummingbird foraging speeds, taken over four decades at multiple localities, show that atypical flowers can be as profitable as typical ones and suggest that the profit can support 24-h metabolic requirements of the birds. Thus, atypical flowers may contribute to successful migration of hummingbirds, enhance their population densities, and allow them to occupy areas seemingly depauperate in suitable resources. These results illustrate what can be gained by attending to the unexpected.
    • Bioclimatic Envelopes for Individual Demographic Events Driven by Extremes: Plant Mortality from Drought and Warming

      Law, Darin J.; Adams, Henry D.; Breshears, David D.; Cobb, Neil S.; Bradford, John B.; Zou, Chris B.; Field, Jason P.; Gardea, Alfonso A.; Williams, A. Park; Huxman, Travis E.; et al. (UNIV CHICAGO PRESS, 2019-01)
      The occurrence of plant species around the globe is largely constrained by climate. Ecologists use plant-climate relationships such as bioclimatic envelopes to determine environmental conditions that promote probable species occurrence. Traditional bioclimatic envelopes exclude disturbance or only include disturbance as infrequent and small-scale effects, assuming that the net effect of climate on demographic processes predicts longer-term equilibrial responses of biota. Because of the increasing frequency and extent of extreme events associated with climate change, ecologists may need to increase focus on individual demographic events driven by extreme events such as large-scale tree die-off. Approaches that predict traditional equilibrial biogeographic responses associated with long-term trends in mean climate could be complemented with an expanded focus on how extreme events catalyze individual demographic events. Extreme conditions of drought are often a prerequisite for abrupt demographic events such as large-scale tree die-off, with the effects of extremes often exacerbated by climatic trends such as warming. In this Perspective, we illustrate the use of bioclimatic envelopes for predicting individual demographic events. Currently, data on conditions that drive individual demographic events are usually aggregated across time and/or are correlative. We highlight this approach with a case study of experimentally drought-induced mortality in Pinus edulis trees, resulting from a combination of ecologically extreme conditions in one parameter and a shifting distribution in another: drought under higher temperatures. Based on this example, we predict a more than fivefold increase in the frequency of die-off events under a global change scenario of high emissions. This general approach complements traditional bioclimatic envelopes and more detailed physiological approaches that are currently being refined to address climate change challenges. Notably, this approach could be developed for other climate conditions and plant species and may improve predictions of abrupt demographic events that are altering ecosystems globally.
    • Coevolution between Mutualists and Parasites in Symbiotic Communities May Lead to the Evolution of Lower Virulence

      Nelson, Paul G.; May, Georgiana; Univ Arizona, Ecol & Evolutionary Biol (UNIV CHICAGO PRESS, 2017-12)
      Most eukaryotes harbor a diverse community of parasitic, mutualistic, and commensal microbial symbionts. Although the diversity of these microbial symbiotic communities has recently drawn considerable attention, theory regarding the evolution of interactions among symbionts and with the host is still in its nascent stages. Here we evaluate the role of interactions among coinfecting symbionts in the evolution of symbiont virulence toward the host. To do so, we place the virulence-transmission trade-off into a community context and model the evolution of symbiont trophic modes along the continuum from parasitism (virulence) to mutualism (negative virulence). We establish a framework for studying multiple infections of a host by the same symbiont species and coinfection by multiple species, using a concept of shared costs, wherein the negative consequences of virulence (or harm) toward the host are shared among symbionts. Our results show that mutualism can be maintained under infection by multiple symbionts when shared costs are sufficiently low, while greater virulence and parasitism toward the host are more likely when shared costs are high. Last, for coinfection by more than one species, we show that if the presence of a mutualist ameliorates some of the costs of pathogen virulence, then the symbiotic community may more often evolve to a more commensal state and maintain mutualisms.
    • Correlation and Late-Stage Deformation of Liv Group Volcanics in the Ross-Delamerian Orogen, Antarctica, from New U-Pb Ages

      Paulsen, Timothy S.; Encarnación, John; Grunow, Anne M.; Stump, Edmund; Pecha, Mark; Valencia, Victor A.; Univ Arizona, Dept Geosci (UNIV CHICAGO PRESS, 2018-05)
      We present new zircon U-Pb isotopic data for volcanic rocks from deformed metavolcanic-sedimentary successions of the widespread Ross Supergroup in the Queen Maud Mountains, Antarctica. Zircon U-Pb analyses of Liv Group volcanic rocks thought to be Neoproterozoic in age instead have early Paleozoic ages. Zircon U-Pb analyses of five samples assigned to the Fairweather Formation have yielded 524 +/- 9 to 514 +/- 9 Ma (2 sigma) crystallization ages, whereas six samples assigned to the Taylor Formation have yielded 510 +/- 12 to 490 +/- 6 Ma (2 sigma) crystallization ages. Although these ages imply that the Fairweather Formation is generally older than the Taylor Formation, the age uncertainties show a 17-My overlap that is consistent with previous suggestions for temporal correlation of these formations. On a regional scale, Liv Group volcanism overlapped with the emplacement of approximate to 535-490 Ma plutonic rocks associated with the early Paleozoic Queen Maud batholith as well as igneous rocks found elsewhere along the early Paleozoic Pacific-Gondwana margin. Collectively, these igneous rocks provide plausible zircon sources for similar age detrital zircon populations found in outboard siliciclastic rocks belonging to the Leverett, Taylor, Fairweather, Greenlee, and Starshot Formations of the Queen Maud Mountains. The youngest crystallization age yielded by the deformed Taylor Formation (approximate to 490 Ma) assumes regional significance because it represents the youngest volcanic rock yet identified within the Ross orogen in Antarctica and provides important new evidence for latest Cambrian or younger deformation, possibly associated with orogenic collapse during slab rollback at the terminal stages of the Ross orogeny.
    • A Critique of Smith’s Constitutivism

      Bukoski, Michael; Univ Arizona, Philosophy (UNIV CHICAGO PRESS, 2016-10)
    • Defensive Symbiosis and the Evolution of Virulence

      Nelson, Paul; May, Georgiana; Univ Arizona, Ecol & Evolutionary Biol (UNIV CHICAGO PRESS, 2020-09)
      A microbiome rife with enemies of the host should cause selection for defensive traits in symbionts, yet such complex environments are also predicted to select for greater symbiont virulence. Why then do we so often observe defensive mutualists that protect hosts while causing little to no damage? To address this question, we build a symbiont-centered model that incorporates the evolution of two independent symbiont traits: defense and virulence. Virulence is modeled as a continuous trait spanning parasitism (positive virulence) and mutualism (negative virulence), thus accounting for the entire range of direct effects that symbionts have on host mortality. Defense is modeled as a continuous trait that ameliorates the costs to the host associated with infection by a deleterious parasite. We show that the evolution of increased defense in one symbiont may lead to the evolution of lower virulence in both symbionts and even facilitate pathogens evolving to mutualism. However, results are context dependent, and when defensive traits are costly, the evolution of greater defense may also lead to the evolution of greater virulence, breaking the common expectation that defensive symbionts are necessarily mutualists toward the host.
    • Dietary Protein and Carbohydrates Affect Immune Function and Performance in a Specialist Herbivore Insect (Manduca sexta)

      Wilson, J Keaton; Ruiz, L; Davidowitz, G; Univ Arizona, Dept Entomol (UNIV CHICAGO PRESS, 2019-01-01)
      Nutrition structures ecology and evolution across all scales of biological organization. It is well known that nutrition can have direct effects on performance and fitness, but indirect effects on physiological systems that mediate biotic interactions have been studied less frequently. Here, we focus on the interaction between nutrition, performance, and the immune system in a specialist herbivorous insect, Manduca sexta. We used a conceptual framework in nutritional ecology (the geometric framework) to examine how changes in diet quality affect aspects of the immune system used for defense against parasitoids. We raised caterpillars throughout their entire larval development on five different experimental diets that varied in protein and carbohydrate content and measured five aspects of the immune system: encapsulation, phenoloxidase activity, prophenoloxidase activity, total hemolymph protein, and hemocyte density. Overall, different parts of the immune function varied in response to interactions between carbohydrates, protein, and intake, but protein reductions had the largest impacts-mostly detrimental. In addition, our data suggest that diet quality mediates the relationship between performance (growth and survival) and immune function, as well as trade-offs among different components of immune function. Our work is the first to examine the interplay between nutrition, performance, and immune function with the geometric framework in a specialist insect herbivore.
    • Discovery of a Giant Chameleon-Like Lizard (Anolis) on Hispaniola and Its Significance to Understanding Replicated Adaptive Radiations.

      Mahler, D Luke; Lambert, Shea M; Geneva, Anthony J; Ng, Julienne; Hedges, S Blair; Losos, Jonathan B; Glor, Richard E; Univ Arizona, Dept Ecol & Evolutionary Biol (UNIV CHICAGO PRESS, 2016-09)
      We report a new chameleon-like Anolis species from Hispaniola that is ecomorphologically similar to congeners found only on Cuba. Lizards from both clades possess short limbs and a short tail and utilize relatively narrow perches, leading us to recognize a novel example of ecomorphological matching among islands in the well-known Greater Antillean anole radiation. This discovery supports the hypothesis that the assembly of island faunas can be substantially deterministic and highlights the continued potential for basic discovery to reveal new insights in well-studied groups. Restricted to a threatened band of midelevation transitional forest near the border of the Dominican Republic and Haiti, this new species appears to be highly endangered.
    • Early Sibling Conflict May Ultimately Benefit the Family

      Smith, Alyssa Laney; Atwater, Daniel Z; Callaway, Ragan M; Univ Arizona, Dept Ecol & Evolutionary Biol (UNIV CHICAGO PRESS, 2019-04-14)
      Relatives often interact differently with each other than with nonrelatives, and whether kin cooperate or compete has important consequences for the evolution of mating systems, seed size, dispersal, and competition. Previous research found that the larger of the size dimorphic seeds produced by the annual plant Aegilops triuncialis suppressed germination of their smaller sibs by 25%-60%. Here, we found evidence for kin recognition and sibling rivalry later in life among Aegilops seedlings that places seed-seed interactions in a broader context. In experiments with size dimorphic seeds, seedlings reduced the growth of sibling seedlings by ∼40% but that of nonsibling seedlings by ∼25%. These sequential antagonistic interactions between seeds and then seedlings provide insight into conflict and cooperation among kin. Kin-based conflict among seeds may maintain dormancy for some seeds until the coast is clear of more competitive siblings. If so, biotically induced seed dormancy may be a unique form of cooperation, which increases the inclusive fitness of maternal plants and offspring by minimizing competition among kin.
    • Effects of Predator Avoidance Behavior on the Coexistence of Competing Prey

      Sommers, Pacifica; Chesson, Peter; Univ Arizona, Ecol & Evolutionary Biol Dept (UNIV CHICAGO PRESS, 2019-05-01)
      Predator avoidance behavior, in which prey limit foraging activities in the presence of predation threats, affects the dynamics of many ecological communities. Despite the growing theoretical appreciation of the role predation plays in coexistence, predator avoidance behavior has yet to be incorporated into the theory in a general way. We introduce adaptive avoidance behavior to a consumer-resource model with three trophic levels to ask whether the ability of prey-the middle trophic level-to avoid predators alters their ability to coexist. We determine the characteristics of cases in which predator avoidance behavior changes prey coexistence or the order of competitive dominance. The mechanism underlying such changes is the weakening of apparent competition relative to resource competition in determining niche overlap, even with resource intake costs. Avoidance behavior thus generally promotes coexistence if prey partition resources but not predators, whereas it undermines coexistence if prey partition predators but not resources. For any given case, the changes in the average fitness difference between two species resulting from avoidance behavior interact with changes in niche overlap to determine coexistence. These results connect the substantial body of theoretical work on avoidance behavior and population dynamics with the body of theory on competitive coexistence.
    • Effects of Road Dust on the Pollination and Reproduction of Wildflowers

      Waser, Nickolas M.; Price, Mary V.; Casco, Genesis; Diaz, Maria; Morales, Asia Liza; Solverson, Jennie; Univ Arizona, Sch Nat Resources & Environm (UNIV CHICAGO PRESS, 2017-02)
      Premise of research. Dust particles and pollen grains are similar in size. Dust deposition might therefore influence the pollination and reproduction of flowering plants. Little is known about such effects, however, despite more general interest in ecological effects of dust. Methodology. We used observational and experimental methods to explore whether dust generated by traffic on unpaved roads affects the amounts of pollen received and numbers of seeds produced by four species of native wildflowers in the western United States. Pivotal results. Flowers of Nuttall's larkspur (Delphinium nuttallianum), scarlet gilia (Ipomopsis aggregata), Lewis flax (Linumlewisii), and sulphur paintbrush (Castilleja sulphurea) growing 1-2mfrom a road received substantially more dust and less pollen than those growing 40-50 m away. We observed the same pattern when we transplanted individuals of the first two species into pots and placed pots near to compared with far from a road. Experimental "hand dusting" of scarlet gilia and Lewis flax plants also reduced stigma pollen loads to a degree that resembled the average effect of road proximity for those species. On the other hand, numbers of seeds per flower ("seed set") did not vary consistently for any species as a function of road proximity or hand-dusting treatment. Conclusions. Several mechanisms might contribute to the different effects of dust on pollen loads and seed set. Wediscuss four possible mechanisms, which we refer to as pollen excess, pollen quality, resource limitation, and compensatory herbivory. These mechanisms suggest avenues for further study of dust, pollination, and plant reproduction with this and other systems.
    • Endotoxin- and Mechanical Stress–Induced Epigenetic Changes in the Regulation of the Nicotinamide Phosphoribosyltransferase Promoter

      Elangovan, Venkateswaran Ramamoorthi; Camp, Sara M.; Kelly, Gabriel T.; Desai, Ankit A.; Adyshev, Djanybek; Sun, Xiaoguang; Black, Stephen M.; Wang, Ting; Garcia, Joe G. N.; Univ Arizona, Dept Med (UNIV CHICAGO PRESS, 2016-12)
      Mechanical ventilation, a lifesaving intervention for patients with acute respiratory distress syndrome (ARDS), also unfortunately contributes to excessive mechanical stress and impaired lung physiological and structural integrity. We have elsewhere established the pivotal role of increased nicotinamide phosphoribosyltransferase (NAMPT) transcription and secretion as well as its direct binding to the toll-like receptor 4 (TLR4) in the progression of this devastating syndrome; however, regulation of this critical gene in ventilator-induced lung injury (VILI) is not well characterized. On the basis of an emerging role for epigenetics in enrichment of VILI and CpG sites within the NAMPT promoter and 5'UTR, we hypothesized that NAMPT expression and downstream transcriptional events are influenced by epigenetic mechanisms. Concomitantly, excessive mechanical stress of human pulmonary artery endothelial cells or lipopolysaccharide (LPS) treatment led to both reduced DNA methylation levels in the NAMPT promoter and increased gene transcription. Histone deacetylase inhibition by trichostatin A or Sirt-1-silencing RNA attenuates LPS-induced NAMPT expression. Furthermore, recombinant NAMPT administration induced TLR4-dependent global H3K9 hypoacetylation. These studies suggest a complex epigenetic regulatory network of NAMPT in VILI and ARDS and open novel strategies for combating VILI and ARDS.
    • Environment shapes invertebrate assemblage structure differences between volcanic spring-fed and runoff rivers in northern California

      Lusardi, Robert A.; Bogan, Michael T.; Moyle, Peter B.; Dahlgren, Randy A.; Univ Arizona, Sch Nat Resources & Environm (UNIV CHICAGO PRESS, 2016-09)
      Flow variability plays an important role in structuring lotic communities, yet comparatively little is known about processes governing assemblage dynamics in stream ecosystems with stable environmental conditions, such as spring-fed rivers. Volcanic spring-fed rivers (hereafter spring-fed rivers) occur in geologically active landscapes of the western USA and around the globe. We sampled invertebrate assemblages and quantified primary productivity and habitat characteristics of spring-fed and runoff rivers in northern California over 4 seasons. We predicted that abiotic factors would be more stable and nutrient availability greater and that invertebrate density would be greater and diversity lower in spring-fed than in runoff rivers. Runoff rivers exhibited high variability in discharge and temperature, whereas spring-fed rivers were relatively stable with high naturally occurring nutrient levels. On average, NO3- and PO43- concentrations were 40x greater in spring-fed than in runoff rivers. Spring-fed rivers supported nearly 7 to 16x greater densities of invertebrates than runoff systems, depending on season. However, invertebrate species richness was greater in runoff rivers in all seasons. Spring-fed river invertebrate assemblages were strongly correlated with elevated nutrient concentrations and basal C sources, whereas runoff assemblages were associated with discharge variability and median substrate size. We suggest that strong differences in abiotic variability between spring-fed and runoff rivers play an important role in determining invertebrate assemblage structure. Because spring-fed rivers exhibit more stable temperatures throughout the year and lower temperatures during the summer than runoff rivers, they may provide essential refugia for coldwater taxa in a warming climate.
    • Explaining Structural Constraints on Lay Participation in Field Science

      Vetter, Jeremy; Univ Arizona, Hist (UNIV CHICAGO PRESS, 2019-06-01)
      Using an example from the author's work on field science in the American West in the early twentieth century, this essay considers how structural constraints on the interactions between scientists and lay people in the field might be explained. Not only is there unusually abundant source evidence about a local ranching family living near a paleontological field site, but the Cooks were especially assertive in attempting to exert influence. This example functions as a thickly documented limiting case for testing the constraints on lay participation in field practice during this period.
    • Expression Profiling Elucidates a Molecular Gene Signature for Pulmonary Hypertension in Sarcoidosis

      Singla, Sunit; Zhou, Tong; Javaid, Kamran; Abbasi, Taimur; Casanova, Nancy; Zhang, Wei; Ma, Shwu-Fan; Wade, Michael S.; Noth, Imre; Sweiss, Nadera J.; et al. (UNIV CHICAGO PRESS, 2016-12)
      Pulmonary hypertension (PH), when it complicates sarcoidosis, carries a poor prognosis, in part because it is difficult to detect early in patients with worsening respiratory symptoms. Pathogenesis of sarcoidosis occurs via incompletely characterized mechanisms that are distinct from the mechanisms of pulmonary vascular remodeling well known to occur in conjunction with other chronic lung diseases. To address the need for a biomarker to aid in early detection as well as the gap in knowledge regarding the mechanisms of PH in sarcoidosis, we used genome-wide peripheral blood gene expression analysis and identified an 18-gene signature capable of distinguishing sarcoidosis patients with PH (n = 8), sarcoidosis patients without PH (n = 17), and healthy controls (n = 45). The discriminative accuracy of this 18-gene signature was 100% in separating sarcoidosis patients with PH from those without it. If validated in a large replicate cohort, this signature could potentially be used as a diagnostic molecular biomarker for sarcoidosis-associated PH.
    • Extraordinary Biomass-Burning Episode and Impact Winter Triggered by the Younger Dryas Cosmic Impact ∼12,800 Years Ago, Parts 1 and 2: A Discussion

      Holliday, Vance T.; Bartlein, Patrick J.; Scott, Andrew C.; Marlon, Jennifer R.; Univ Arizona, Dept Geosci (UNIV CHICAGO PRESS, 2019-12-05)
    • Forager Mobility in Constructed Environments

      Haas, Randall; Kuhn, Steven L.; Univ Arizona, Sch Anthropol (UNIV CHICAGO PRESS, 2019-07-19)
      As obligate tool users, humans habitually reconfigure resource distributions on landscapes. Such resource restructuring would have played a nontrivial role in shaping hunter-gatherer mobility decisions and emergent land-use patterns. This paper presents a model of hunter-gatherer mobility in which the habitual deposition of material resources at places on landscapes biases the future mobility decisions of energy-optimizing foragers. Thus foragers effectively construct the environments to which they adapt. With the aid of an agent-based model, this simple niche-construction model is used to deduce four predictions for emergent structure in hunter-gatherer settlement patterns. The predictions are tested against archaeological data from a hunter-gatherer settlement system in the Lake Titicaca Basin, Peru, 7,000–5,000 cal BP. Good agreement is found between the predicted and empirical patterns, demonstrating the model’s efficacy and suggesting a behavioral explanation for structural properties of hunter-gatherer settlement systems. The niche-construction behavior and its self-organized properties may have been key components in the emergence of socioeconomic complexity in human societies.
    • From Legal Doctrine to Social Transformation? Comparing U.S. Voting Rights, Equal Employment Opportunity, and Fair Housing Legislation

      Pedriana, Nicholas; Stryker, Robin; Univ Arizona, Sociol; Univ Arizona, Law; Univ Arizona, Govt & Publ Policy (UNIV CHICAGO PRESS, 2017-07)
      In 1964-68, the U.S. Congress enacted comprehensive legislation prohibiting discrimination in employment (1964 Civil Rights Act), voting (1965 Voting Rights Act), and housing (1968 Fair Housing Act). A half-century later, most scholars concur that voting rights was by far the most successful, fair housing was a general failure, and Title VII fell somewhere in between. Explanations of civil rights effectiveness in political sociology that emphasize state-internal resources and capacities, policy entrepreneurship, and/or the degree of white resentment cannot explain this specific outcome hierarchy. Pertinent to President Trump's policies, the authors propose an alternative hypothesis grounded in the sociology of law: the comparative effectiveness of civil rights policies is best explained by the extent to which each policy incorporated a group-centered effects (GCE) statutory and enforcement framework. Focusing on systemic group disadvantage rather than individual harm, discriminatory consequences rather than discriminatory intent, and substantive group results over individual justice, GCE offers an alternative theoretical framework for analyzing comparative civil rights outcomes.