• Abundance and habitat relationships of breeding birds in the Sky Islands and adjacent Sierra Madre Occidental of northwest Mexico

      Flesch, Aaron D.; Gonzalez Sanchez, Carlos; Valenzuela Amarillas, Javier; Univ Arizona, Desert Lab, Sch Nat Resources & Environm (WILEY-BLACKWELL, 2016-06)
      The Sierra Madre Occidental and neighboring Madrean Sky Islands span a large and biologically diverse region of northwest Mexico and portions of the southwestern United States. Little is known about the abundance and habitat use of breeding birds in this region of Mexico, but such information is important for guiding conservation and management. We assessed densities and habitat relationships of breeding birds across Sky Island mountain ranges in Mexico and adjacent portions of the Sierra Madre from 2009 to 2012. We estimated densities at multiple spatial scales, assessed variation in densities among all major montane vegetation communities, and identified and estimated the effects of important habitat attributes on local densities. Regional density estimates of 65% of 72 focal species varied significantly among eight montane vegetation communities that ranged from oak savannah and woodland at low elevations to pine and mixed-conifer forest at high elevations. Greater proportions of species occurred at peak densities or were relatively restricted to mixed-conifer forest and montane riparian vegetation likely because of higher levels of structural or floristic diversity in those communities, but those species were typically rare or uncommon in the Sky Islands. Fewer species had peak densities in oak and pine-oak woodland, and species associated with those communities were often more abundant across the region. Habitat models often included the effects of broadleaf deciduous vegetation cover (30% of species), which, together with tree density and fire severity, had positive effects on densities and suggest ways for managers to augment and conserve populations. Such patterns combined with greater threats to high-elevation conifer forest and riparian areas underscore their value for conservation. Significant populations of many breeding bird species, including some that are of concern or were not known to occur regionally or in mountain ranges we surveyed, highlight the importance of conservation efforts in this area of Mexico.
    • The acceptance of mobile teledermoscopy by primary care nurse practitioners in the state of Arizona.

      Stratton, Delaney; Loescher, Lois J; Univ Arizona, Coll Nursing (WILEY-BLACKWELL, 2016-06)
      To conduct a pilot survey to assess acceptance of mobile teledermoscopy (MTD) by primary care nurse practitioners (NPs) working in Arizona.
    • Acute systemic DNA damage in youth does not impair immune defense with aging

      Pugh, Jason L.; Foster, Sarah A.; Sukhina, Alona S.; Petravic, Janka; Uhrlaub, Jennifer L.; Padilla-Torres, Jose; Hayashi, Tomonori; Nakachi, Kei; Smithey, Megan J.; Nikolich-Žugich, Janko; et al. (WILEY-BLACKWELL, 2016-08)
      Aging-related decline in immunity is believed to be the main driver behind decreased vaccine efficacy and reduced resistance to infections in older adults. Unrepaired DNA damage is known to precipitate cellular senescence, which was hypothesized to be the underlying cause of certain age-related phenotypes. Consistent with this, some hallmarks of immune aging were more prevalent in individuals exposed to whole-body irradiation (WBI), which leaves no anatomical repository of undamaged hematopoietic cells. To decisively test whether and to what extent WBI in youth will leave a mark on the immune system as it ages, we exposed young male C57BL/ 6 mice to sublethal WBI (0.5-4 Gy), mimicking human survivor exposure during nuclear catastrophe. We followed lymphocyte homeostasis thorough the lifespan, response to vaccination, and ability to resist lethal viral challenge in the old age. None of the irradiated groups showed significant differences compared with mock-irradiated (0 Gy) animals for the parameters measured. Even the mice that received the highest dose of sublethal WBI in youth (4 Gy) exhibited equilibrated lymphocyte homeostasis, robust T-and B-cell responses to live attenuated West Nile virus (WNV) vaccine and full survival following vaccination upon lethal WNV challenge. Therefore, a single dose of nonlethal WBI in youth, resulting in widespread DNA damage and repopulation stress in hematopoietic cells, leaves no significant trace of increased immune aging in a lethal vaccine challenge model.
    • Altered natal dispersal at the range periphery: The role of behavior, resources, and maternal condition

      Merrick, Melissa J.; Koprowski, John L.; Univ Arizona, Sch Nat Resources & Environm, Wildlife Conservat & Management; School of Natural Resources and the Environment; Wildlife Conservation and Management; University of Arizona; Tucson AZ USA; School of Natural Resources and the Environment; Wildlife Conservation and Management; University of Arizona; Tucson AZ USA (WILEY-BLACKWELL, 2017-01)
      Natal dispersal outcomes are an interplay between environmental conditions and individual phenotypes. Peripheral, isolated populations may experience altered environmental conditions and natal dispersal patterns that differ from populations in contiguous landscapes. We document nonphilopatric, sex-biased natal dispersal in an endangered small mammal, the Mt. Graham red squirrel (Tamiasciurus hudsonicus grahamensis), restricted to a single mountain. Other North American red squirrel populations are shown to have sex-unbiased, philopatric natal dispersal. We ask what environmental and intrinsic factors may be driving this atypical natal dispersal pattern. We test for the influence of proximate factors and ultimate drivers of natal dispersal: habitat fragmentation, local population density, individual behavior traits, inbreeding avoidance, competition for mates, and competition for resources, allowing us to better understand altered natal dispersal patterns at the periphery of a species' range. A juvenile squirrel's body condition and its mother's mass in spring (a reflection of her intrinsic quality and territory quality) contribute to individual behavioral tendencies for movement and exploration. Resources, behavior, and body condition have the strongest influence on natal dispersal distance, but affect males and females differently. Male natal dispersal distance is positively influenced by its mother's spring body mass and individual tendency for movement; female natal dispersal distance is negatively influenced by its mother's spring body mass and positively influenced by individual tendency for movement. An apparent feedback between environmental variables and subsequent juvenile behavioral state contributes to an altered natal dispersal pattern in a peripheral population, highlighting the importance of studying ecological processes at the both range center and periphery of species' distributions.
    • Ant-plant mutualism: a dietary by-product of a tropical ant's macronutrient requirements

      Arcila Hernández, Lina M; Sanders, Jon G; Miller, Gabriel A; Ravenscraft, Alison; Frederickson, Megan E; Univ Arizona, Ctr Insect Sci (WILEY-BLACKWELL, 2017-10-04)
      Many arboreal ants depend on myrmecophytic plants for both food and shelter; in return, these ants defend their host plants against herbivores, which are often insects. Ant–plant and other mutualisms do not necessarily involve the exchange of costly rewards or services; they may instead result from by‐product benefits, or positive outcomes that do not entail a cost for one or both partners. Here, we examined whether the plant‐ant Allomerus octoarticulatus pays a short‐term cost to defend their host plants against herbivores, or whether plant defense is a by‐product benefit of ant foraging for insect prey. Because the food offered by ant‐plants is usually nitrogen‐poor, arboreal ants may balance their diets by consuming insect prey or associating with microbial symbionts to acquire nitrogen, potentially shifting the costs and benefits of plant defense for the ant partner. To determine the effect of ant diet on an ant–plant mutualism, we compared the behavior, morphology, fitness, stable isotope signatures, and gaster microbiomes of A. octoarticulatus ants nesting in Cordia nodosa trees maintained for nearly a year with or without insect herbivores. At the end of the experiment, ants from herbivore exclosures preferred protein‐rich baits more than ants in the control (i.e., herbivores present) treatment. Furthermore, workers in the control treatment were heavier than in the herbivore‐exclusion treatment, and worker mass predicted reproductive output, suggesting that foraging for insect prey directly increased ant colony fitness. The gaster microbiome of ants was not significantly affected by the herbivore exclusion treatment. We conclude that the defensive behavior of some phytoecious ants is a by‐product of their need for external protein sources; thus, the consumption of insect herbivores by ants benefits both the ant colony and the host plant.
    • The Argonaute-binding platform of NRPE1 evolves through modulation of intrinsically disordered repeats

      Trujillo, Joshua T.; Beilstein, Mark A.; Mosher, Rebecca A.; The School of Plant Sciences, The University of Arizona; The School of Plant Sciences; The University of Arizona; Tucson AZ 85721-0036 USA; The School of Plant Sciences; The University of Arizona; Tucson AZ 85721-0036 USA; The School of Plant Sciences; The University of Arizona; Tucson AZ 85721-0036 USA (WILEY-BLACKWELL, 2016-12)
      • Argonaute proteins are important effectors in RNA silencing pathways, but they must interact with other machinery to trigger silencing. Ago hooks have emerged as a conserved motif responsible for interaction with Argonaute proteins, but little is know about the sequence surrounding Ago hooks that must restrict or enable interaction with specific Argonautes. • Here we investigated the evolutionary dynamics of an Argonaute-binding platform in NRPE1, the largest subunit of RNA Polymerase V. We compared NRPE1 sequences from more than 50 species, including dense sampling of two plant lineages. • This study demonstrates that the Argonaute-binding platform of NRPE1 retains Ago-hooks, intrinsic disorder, and repetitive character while being highly labile at the sequence level. We reveal that loss of sequence conservation is due to relaxed selection and frequent expansions and contractions of tandem repeat arrays. These factors allow a complete restructuring of the Ago-binding platform over 50-60 million years. This evolutionary pattern is also detected in a second Ago-binding platform, suggesting it is a general mechanism. • The presence of labile repeat arrays in all analyzed NRPE1 Ago-binding platforms indicates that selection maintains repetitive character, potentially to retain the ability to rapidly restructure the Ago-binding platform.
    • Between control and complexity: opportunities and challenges for marine mesocosms

      Sagarin, Raphael D; Adams, John; Blanchette, Carol A; Brusca, Richard C; Chorover, Jon; Cole, Julia E; Micheli, Fiorenza; Munguia-Vega, Adrian; Rochman, Chelsea M; Bonine, Kevin; et al. (WILEY-BLACKWELL, 2016-09)
      Marine ecologists have a wide array of tools with which to study complex and dynamic systems, but there are cases where neither simple, highly controlled experiments nor largely uncontrolled, more complex field observations provide adequate inferential power. In such cases, mesocosm studies in marine systems may help bridge the gap. Mesocosm studies can facilitate research ranging from basic biology to multifactorial ecosystem studies that involve observation, perturbation, validation, calibration, long-term studies, and testing of new technologies. Although scale, closed boundaries, biodiversity levels, and replication can impose challenges on mesocosm research, these parameters can also help to define research opportunities that are uniquely suited to such controlled environments. Finally, we provide examples of successful marine mesocosm research and discuss opportunities for future work.
    • Biogeochemistry drives diversity in the prokaryotes, fungi, and invertebrates of a Panama forest

      Kaspari, Michael; Bujan, Jelena; Weiser, Michael D.; Ning, Daliang; Michaletz, Sean T.; Zhili, He; Enquist, Brian J.; Waide, Robert B.; Zhou, Jizhong; Turner, Benjamin L.; et al. (WILEY-BLACKWELL, 2017-05-13)
      Humans are both fertilizing the world and depleting its soils, decreasing the diversity of aquatic ecosystems and terrestrial plants in the process. We know less about how nutrients shape the abundance and diversity of the prokaryotes, fungi, and invertebrates of Earth's soils. Here we explore this question in the soils of a Panama forest subject to a 13‐yr fertilization with factorial combinations of nitrogen (N), phosphorus (P), and potassium (K) and a separate micronutrient cocktail. We contrast three hypotheses linking biogeochemistry to abundance and diversity. Consistent with the Stress Hypothesis, adding N suppressed the abundance of invertebrates and the richness of all three groups of organisms by ca. 1 SD or more below controls. Nitrogen addition plots were 0.8 pH units more acidic with 18% more exchangeable aluminum, which is toxic to both prokaryotes and eukaryotes. These stress effects were frequently reversed, however, when N was added with P (for prokaryotes and invertebrates) and with added K (for fungi). Consistent with the Abundance Hypothesis, adding P generally increased prokaryote and invertebrate diversity, and adding K enhanced invertebrate diversity. Also consistent with the Abundance Hypothesis, increases in invertebrate abundance generated increases in richness. We found little evidence for the Competition Hypothesis: that single nutrients suppressed diversity by favoring a subset of high nutrient specialists, and that nutrient combinations suppressed diversity even more. Instead, combinations of nutrients, and especially the cation/micronutrient treatment, yielded the largest increases in richness in the two eukaryote groups. In sum, changes in soil biogeochemistry revealed a diversity of responses among the three dominant soil groups, positive synergies among nutrients, and–in contrast with terrestrial plants–the frequent enhancement of soil biodiversity.
    • Caching rodents disproportionately disperse seed beneath invasive grass

      Sommers, Pacifica; Chesson, Peter; Univ Arizona, Ecol & Evolutionary Biol (WILEY-BLACKWELL, 2017-02-07)
      Seed dispersal by caching rodents is a context-dependent mutualism in many systems. Plants benefit when seed remaining in shallow caches germinates before being eaten, often gaining protection from beetles and a favorable microsite in the process. Caching in highly unfavorable microsites, conversely, could undermine the dispersal benefit for the plant. Plant invasions could disrupt dispersal benefits of seed caching by attracting rodents to the protection of a dense invasive canopy which inhibits the establishment of native seedlings beneath it. To determine whether rodents disproportionately cache seed under the dense canopy of an invasive grass in southeastern Arizona, we used nontoxic fluorescent powder and ultraviolet light to locate caches of seed offered to rodents in the field. We fitted a general habitat-use model, which showed that disproportionate use of plant cover by caching rodents (principally Chaetodipus spp.) increased with moonlight. Across all moon phases, when rodents cached under plants, they cached under the invasive grass disproportionately to its relative cover. A greenhouse experiment showed that proximity to the invasive grass reduced the growth and survival of seedlings of a common native tree (Parkinsonia microphylla) whose seeds are dispersed by caching rodents. Biased dispersal of native seed to the base of an invasive grass could magnify the competitive effect of this grass on native plants, further reducing their recruitment and magnifying the effect of the invasion.
    • Check-hybrid GLDPC codes: Systematic elimination of trapping sets and guaranteed error correction capability

      Ravanmehr, Vida; Khatami, Mehrdad; Declercq, David; Vasic, Bane; Univ Arizona, Dept Elect & Comp Engn (WILEY-BLACKWELL, 2016-10-12)
      In this paper, we propose a new approach to construct a class of check-hybrid generalized low-density parity-check (CH-GLDPC) codes, which are free of small trapping sets. The approach is based on converting some selected check nodes involving a trapping set into super checks corresponding to a 2-error-correcting component code. Specifically, we follow 2 main purposes to construct the check-hybrid codes; first, on the basis of the knowledge of trapping sets of an LDPC code, single parity checks are replaced by super checks to disable the trapping sets. We show that by converting specified single check nodes, denoted as critical checks, to super checks in a trapping set, the parallel bit flipping decoder corrects the errors on a trapping set. The second purpose is to minimize the rate loss through finding the minimum number of such critical checks. We also present an algorithm to find critical checks in a trapping set of a column-weight 3 LDPC code of girth 8 and then provide upper bounds on the minimum number of such critical checks such that the decoder corrects all error patterns on elementary trapping sets. Guaranteed error correction capability of the CH-GLDPC codes is also studied. We show that a CH-GLDPC code in which each variable node is connected to 2 super checks corresponding to a 2-error-correcting component code corrects up to 5 errors. The results are also extended to column-weight 4 LDPC codes of girth 6. Finally, we investigate eliminating of trapping sets of a column-weight 3 LDPC code of girth 8 using the Gallager B decoding algorithm.
    • A chronic care ostomy self-management program for cancer survivors.

      Krouse, Robert S; Grant, Marcia; McCorkle, Ruth; Wendel, Christopher S; Cobb, Martha D; Tallman, Nancy J; Ercolano, Elizabeth; Sun, Virginia; Hibbard, Judith H; Hornbrook, Mark C; et al. (WILEY-BLACKWELL, 2016-05)
      Individuals with ostomies experience extensive changes in health-related quality of life (HRQOL) and daily routine. Patients and families are typically forced to use trial and error to improve self-management.
    • Climate change is advancing spring onset across the U.S. national park system

      Monahan, William B.; Rosemartin, Alyssa; Gerst, Katharine L.; Fisichelli, Nicholas A.; Ault, Toby; Schwartz, Mark D.; Gross, John E.; Weltzin, Jake F.; Univ Arizona, Sch Nat Resources & Environm; Inventory and Monitoring Division; National Park Service; Natural Resource Stewardship and Science; 1201 Oakridge Drive Fort Collins Colorado 80525 USA; et al. (WILEY-BLACKWELL, 2016-10)
      Many U.S. national parks are already at the extreme warm end of their historical temperature distributions. With rapidly warming conditions, park resource management will be enhanced by information on seasonality of climate that supports adjustments in the timing of activities such as treating invasive species, operating visitor facilities, and scheduling climate-related events (e.g., flower festivals and fall leaf-viewing). Seasonal changes in vegetation, such as pollen, seed, and fruit production, are important drivers of ecological processes in parks, and phenology has thus been identified as a key indicator for park monitoring. Phenology is also one of the most proximate biological responses to climate change. Here, we use estimates of start of spring based on climatically modeled dates of first leaf and first bloom derived from indicator plant species to evaluate the recent timing of spring onset (past 10-30 yr) in each U.S. natural resource park relative to its historical range of variability across the past 112 yr (1901-2012). Of the 276 high latitude to subtropical parks examined, spring is advancing in approximately three-quarters of parks (76%), and 53% of parks are experiencing "extreme" early springs that exceed 95% of historical conditions. Our results demonstrate how changes in climate seasonality are important for understanding ecological responses to climate change, and further how spatial variability in effects of climate change necessitates different approaches to management. We discuss how our results inform climate change adaptation challenges and opportunities facing parks, with implications for other protected areas, by exploring consequences for resource management and planning.
    • Contesting Digital Futures: Urban Politics, Alternative Economies, and the Movement for Technological Sovereignty in Barcelona

      Lynch, Casey R.; Univ Arizona, Sch Geog & Dev (WILEY-BLACKWELL, 2019-03-12)
      Scholars have offered important critiques of the socio‐spatial processes of contemporary technological development, including the rise of “smart city” urban development models. While these critiques have been essential for understanding contemporary forms of techno‐capitalism and their reach into new areas, this paper calls for a consideration of alternative modes of digital development in urban life beyond the logics of securitisation and capital accumulation. In particular, I examine the critical discourses and experimental practices of a grassroots movement focused on claiming “technological sovereignty” (TS) in Barcelona. The TS movement is a broad, de‐centralised network of cooperatives, associations, and community initiatives experimenting with alternative practices of locally rooted, open‐source digital development. These groups explore democratic and cooperative practices of work, property, production, and consumption in relation to digital technology, based around an ethics of care and a commitment to working through and within local communities. In examining the values, beliefs, and practices of the TS movement, I bring ongoing discussions around digitalisation and the “smart city” into critical conversation with the extensive literature on prefigurative urban politics and postcapitalist economies.
    • Contextual organismality: Beyond pattern to process in the emergence of organisms

      Díaz-Muñoz, Samuel L.; Boddy, Amy M.; Dantas, Gautam; Waters, Christopher M.; Bronstein, Judith L.; Department of Ecology and Evolutionary Biology, University of Arizona; Center for Genomics and Systems Biology and Department of Biology; New York University; New York New York 10003; Department of Psychology; Arizona State University; Tempe Arizona 85281; Department of Pathology and Immunology, Center for Genome Sciences and Systems Biology; Washington University School of Medicine; St. Louis Missouri 63110; Department of Microbiology and Molecular Genetics, 5180 Biomedical Physical Sciences; Michigan State University; East Lansing Michigan 48824; et al. (WILEY-BLACKWELL, 2016-12)
      Biologists have taken the concept of organism largely for granted. However, advances in the study of chimerism, symbiosis, bacterial-eukaryote associations, and microbial behavior have prompted a redefinition of organisms as biological entities exhibiting low conflict and high cooperation among their parts. This expanded view identifies organisms in evolutionary time. However, the ecological processes, mechanisms, and traits that drive the formation of organisms remain poorly understood. Recognizing that organismality can be context dependent, we advocate elucidating the ecological contexts under which entities do or do not act as organisms. Here we develop a "contextual organismality" framework and provide examples of entities, such as honey bee colonies, tumors, and bacterial swarms, that can act as organisms under specific life history, resource, or other ecological circumstances. We suggest that context dependence may be a stepping stone to the development of increased organismal unification, as the most integrated biological entities generally show little context dependence. Recognizing that organismality is contextual can identify common patterns and testable hypotheses across different entities. The contextual organismality framework can illuminate timeless as well as pressing issues in biology, including topics as disparate as cancer emergence, genomic conflict, evolution of symbiosis, and the role of the microbiota in impacting host phenotype.
    • Drought, pollen and nectar availability, and pollination success

      Waser, Nickolas M.; Price, Mary V.; Univ Arizona, Sch Nat Resources & Environm; Rocky Mountain Biological Laboratory; P. O. Box 519 Crested Butte Colorado 81224 USA; Rocky Mountain Biological Laboratory; P. O. Box 519 Crested Butte Colorado 81224 USA (WILEY-BLACKWELL, 2016-06)
      Pollination success of animal-pollinated flowers depends on rate of pollinator visits and on pollen deposition per visit, both of which should vary with the pollen and nectar "neighborhoods" of a plant, i.e., with pollen and nectar availability in nearby plants. One determinant of these neighborhoods is per-flower production of pollen and nectar, which is likely to respond to environmental influences. In this study, we explored environmental effects on pollen and nectar production and on pollination success in order to follow up a surprising result from a previous study: flowers of Ipomopsis aggregata received less pollen in years of high visitation by their hummingbird pollinators. A new analysis of the earlier data indicated that high bird visitation corresponded to drought years. We hypothesized that drought might contribute to the enigmatic prior result if it decreases both nectar and pollen production: in dry years, low nectar availability could cause hummingbirds to visit flowers at a higher rate, and low pollen availability could cause them to deposit less pollen per visit. A greenhouse experiment demonstrated that drought does reduce both pollen and nectar production by I. aggregata flowers. This result was corroborated across 6 yr of variable precipitation and soil moisture in four unmanipulated field populations. In addition, experimental removal of pollen from flowers reduced the pollen received by nearby flowers. We conclude that there is much to learn about how abiotic and biotic environmental drivers jointly affect pollen and nectar production and availability, and how this contributes to pollen and nectar neighborhoods and thus influences pollination success.
    • Evaluating IPMN and pancreatic carcinoma utilizing quantitative histopathology

      Glazer, Evan S.; Zhang, Hao Helen; Hill, Kimberly A.; Patel, Charmi; Kha, Stephanie T.; Yozwiak, Michael L.; Bartels, Hubert; Nafissi, Nellie N.; Watkins, Joseph C.; Alberts, David S.; et al. (WILEY-BLACKWELL, 2016-10)
      Intraductal papillary mucinous neoplasms (IPMN) are pancreatic lesions with uncertain biologic behavior. This study sought objective, accurate prediction tools, through the use of quantitative histopathological signatures of nuclear images, for classifying lesions as chronic pancreatitis (CP), IPMN, or pancreatic carcinoma (PC). Forty-four pancreatic resection patients were retrospectively identified for this study (12 CP; 16 IPMN; 16 PC). Regularized multinomial regression quantitatively classified each specimen as CP, IPMN, or PC in an automated, blinded fashion. Classification certainty was determined by subtracting the smallest classification probability from the largest probability (of the three groups). The certainty function varied from 1.0 (perfectly classified) to 0.0 (random). From each lesion, 180 +/- 22 nuclei were imaged. Overall classification accuracy was 89.6% with six unique nuclear features. No CP cases were misclassified, 1/16 IPMN cases were misclassified, and 4/16 PC cases were misclassified. Certainty function was 0.75 +/- 0.16 for correctly classified lesions and 0.47 +/- 0.10 for incorrectly classified lesions (P = 0.0005). Uncertainty was identified in four of the five misclassified lesions. Quantitative histopathology provides a robust, novel method to distinguish among CP, IPMN, and PC with a quantitative measure of uncertainty. This may be useful when there is uncertainty in diagnosis.
    • Examining variation in the leaf mass per area of dominant species across two contrasting tropical gradients in light of community assembly

      Neyret, Margot; Bentley, Lisa Patrick; Oliveras, Imma; Marimon, Beatriz S.; Marimon-Junior, Ben Hur; Almeida de Oliveira, Edmar; Barbosa Passos, Fábio; Castro Ccoscco, Rosa; dos Santos, Josias; Matias Reis, Simone; et al. (WILEY-BLACKWELL, 2016-08)
      Understanding variation in key functional traits across gradients in high diversity systems and the ecology of community changes along gradients in these systems is crucial in light of conservation and climate change. We examined inter- and intraspecific variation in leaf mass per area (LMA) of sun and shade leaves along a 3330-m elevation gradient in Peru, and in sun leaves across a forest-savanna vegetation gradient in Brazil. We also compared LMA variance ratios (T-statistics metrics) to null models to explore internal (i.e., abiotic) and environmental filtering on community structure along the gradients. Community- weighted LMA increased with decreasing forest cover in Brazil, likely due to increased light availability and water stress, and increased with elevation in Peru, consistent with the leaf economic spectrum strategy expected in colder, less productive environments. A very high species turnover was observed along both environmental gradients, and consequently, the first source of variation in LMA was species turnover. Variation in LMA at the genus or family levels was greater in Peru than in Brazil. Using dominant trees to examine possible filters on community assembly, we found that in Brazil, internal filtering was strongest in the forest, while environmental filtering was observed in the dry savanna. In Peru, internal filtering was observed along 80% of the gradient, perhaps due to variation in taxa or interspecific competition. Environmental filtering was observed at cloud zone edges and in lowlands, possibly due to water and nutrient availability, respectively. These results related to variation in LMA indicate that biodiversity in species rich tropical assemblages may be structured by differential niche-based processes. In the future, specific mechanisms generating these patterns of variation in leaf functional traits across tropical environmental gradients should be explored.
    • Exploration of early-life candidate biomarkers for childhood asthma using antibody arrays

      Xu, Haili; Radabaugh, Timothy; Lu, Zhenqiang; Galligan, Michael; Billheimer, Dean; Vercelli, Donata; Wright, Anne L.; Monks, Terrence J.; Halonen, Marilyn; Lau, Serrine S.; et al. (WILEY-BLACKWELL, 2016-11)
      Background: Proteomic approaches identifying biomarkers have been applied to asthma to only a very limited extent. Methods: With an antibody array (RayBiotech, Norcross, GA, USA), the relative intensity and rank differences of 444 proteins were compared in 24 plasma samples obtained at age 3, 11 from children with and 12 without asthma diagnoses at ages 5 and 9. Protein candidates identified by antibody array were quantitated by ELISA in an enlarged sample. Proteins found to differentiate children with and without asthma were also examined for association with known Year 1 asthma risk factors, eczema, and wheeze. Results: In the antibody array, four proteins had rank differences between asthma and non-asthma groups (FDR < 0.1). By ELISA, mean log (+/- s.e.m.) erythropoietin (EPO) level (IU/l) was lower (0.750 +/- 0.048 vs. 0.898 +/- 0.035; p = 0.006) and mean (+/- s.e.m.) soluble GP130 (sGP130) level (ng/ml) was higher in the asthma vs. the non-asthma group (302 +/- 13 vs. 270 +/- 8; p = 0.041). The other 2 array proteins (galactin-3 and eotaxin-3) did not differ by ELISA by asthma. EPO related to the asthma risk factor, first year eczema, whereas sGP130 related to first year wheeze. Conclusions: Through two independent assessments, age 3 plasma levels of EPO and sGP130 were found related to childhood asthma.
    • The Gao-Guenie impact melt breccia-Sampling a rapidly cooled impact melt dike on an H chondrite asteroid?

      Swindle, Timothy D.; Schmieder, Martin; Kring, David A.; Bond, Jade C.; Moore, Carleton B.; Univ Arizona, Lunar & Planetary Lab (WILEY-BLACKWELL, 2016-06)
      The Gao-Guenie H5 chondrite that fell on Burkina Faso (March 1960) has portions that were impact-melted on an H chondrite asteroid at similar to 300 Ma and, through later impact events in space, sent into an Earth-crossing orbit. This article presents a petrographic and electron microprobe analysis of a representative sample of the Gao-Guenie impact melt breccia consisting of a chondritic clast domain, quenched melt in contact with chondritic clasts, and an igneous-textured impact melt domain. Olivine is predominantly Fo(80-82). The clast domain contains low-Ca pyroxene. Impact melt-grown pyroxene is commonly zoned from low-Ca pyroxene in cores to pigeonite and augite in rims. Metal-troilite orbs in the impact melt domain measure up to similar to 2 mm across. The cores of metal orbs in the impact melt domain contain similar to 7.9 wt% of Ni and are typically surrounded by taenite and Ni-rich troilite. The metallography of metal-troilite droplets suggest a stage I cooling rate of order 10 degrees C s(-1) for the superheated impact melt. The subsolidus stage II cooling rate for the impact melt breccia could not be determined directly, but was presumably fast. An analogy between the Ni rim gradients in metal of the Gao-Guenie impact melt breccia and the impact-melted H6 chondrite Orvinio suggests similar cooling rates, probably on the order of similar to 5000-40,000 degrees C yr(-1). A simple model of conductive heat transfer shows that the Gao-Guenie impact melt breccia may have formed in a melt injection dike similar to 0.5-5 m in width, generated during a sizeable impact event on the H chondrite parent asteroid.
    • GET OUT THE (COSTLY) VOTE: INSTITUTIONAL DESIGN FOR GREATER PARTICIPATION

      Gerardi, Dino; McConnell, Margaret A.; Romero, Julian; Yariv, Leeat; University of Arizona; Carlo Alberto Chaired Professor of Economic Organization and Scientific Innovation, Collegio Carlo Alberto; Università di Torino; Torino 10024 Italy; Assistant Professor Global Health Economics, Global Health and Population; Harvard School of Public Health; Boston MA 02115; Assistant Professor of Economics, Department of Economics; University of Arizona; Tucson AZ 85721; Professor of Economics, Division of Humanities and Social Sciences; California Institute of Technology; Pasadena CA 91125 (WILEY-BLACKWELL, 2016-10)
      We examine two commonly discussed institutions inducing turnout: abstention penalties ( used in 32 countries) and lotteries rewarding one randomly chosen participant ( as proposed on the 2006 Arizona ballot). We analyze a benchmark model in which voters vary in their information quality and participation is costly. We illustrate that both institutions can improve collective outcomes, though lotteries are a more effective instrument asymptotically. Experimentally, we provide strong evidence for selective participation: lab voters participate more when better informed or when institutionally induced. Lotteries fare better than fines, suggesting that they may be a useful alternative to commonly used compulsory voting schemes.