96 research outputs found

    Integrating existing climate adaptation planning into future visions: A strategic scenario for the central Arizona–Phoenix region

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    Cities face a number of challenges to ensure that people’s well-being and ecosystem integrity are not only maintained but improved for current and future generations. Urban planning must account for the diverse and changing interactions among the social, ecological, and technological systems (SETS) of a city. Cities struggle with long-range approaches to explore, anticipate, and plan for sustainability and resilience—and scenario development is one way to address this need. In this paper, we present the framework for developing what we call ‘strategic’ scenarios, which are scenarios or future visions created from governance documents expressing unrealized municipal priorities and goals. While scenario approaches vary based on diverse planning and decision-making objectives, only some offer tangible, systemic representations of existing plans and goals for the future that can be explored as an assessment and planning tool for sustainability and resilience. Indeed, the strategic scenarios approach presented here (1) emphasizes multi-sectoral and interdisciplinary interventions; (2) identifies systemic conflicts, tradeoffs, and synergies among existing planning goals; and (3) incorporates as yet unrealized goals and strategies representative of urban short-term planning initiatives. We present an example strategic scenario for the Central Arizona–Phoenix metropolitan region, and discuss the utility of the strategic scenario in long-term thinking for future sustainability and resilience in urban research and practice. This approach brings together diverse—sometimes competing—strategies and offers the opportunity to explore outcomes by comparing and contrasting their implications and tradeoffs, and evaluating the resulting strategic scenario against scenarios developed through alternative, participatory approaches

    The Co-Production of Sustainable Future Scenarios

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    Scenarios are a tool to develop plausible, coherent visions about the future and to foster anticipatory knowledge. We present the Sustainable Future Scenarios (SFS) framework and demonstrate its application through the Central Arizona-Phoenix Long-term Ecological Research (CAP LTER) urban site. The SFS approach emphasizes the co-development of positive and long-term alternative future visions. Through a collaboration of practitioner and academic stakeholders, this research integrates participatory scenario development, modeling, and qualitative scenario assessments. The SFS engagement process creates space to question the limits of what is normally considered possible, desirable, or inevitable in the face of future challenges. Comparative analyses among the future scenarios demonstrate trade-offs among regional and microscale temperature, water use, land-use change, and co-developed resilience and sustainability indices. SFS incorporate diverse perspectives in co-producing positive future visions, thereby expanding traditional future projections. The iterative, interactive process also creates opportunities to bridge science and policy by building anticipatory and systems-based decision-making and research capacity for long-term sustainability planning

    Photoluminescence of Fully Inorganic Colloidal Gold Nanocluster and Their Manipulation Using Surface Charge Effects

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    International audienceFully inorganic, colloidal gold nanoclusters (NCs) constitute a new class of nanomaterials that are clearly distinguishable from their commonly studied metal–organic ligand-capped counterparts. As their synthesis by chemical methods is challenging, details about their optical properties remain widely unknown. In this work, laser fragmentation in liquids is performed to produce fully inorganic and size-controlled colloidal gold NCs with monomodal particle size distributions and an fcc-like structure. Results reveal that these NCs exhibit highly pronounced photoluminescence with quantum yields of 2%. The emission behavior of small (2–2.5 nm) and ultrasmall (<1 nm) NCs is significantly different and dominated by either core- or surface-based emission states. It is further verified that emission intensities are a function of the surface charge density, which is easily controllable by the pH of the surrounding medium. This experimentally observed correlation between surface charge and photoluminescence emission intensity is confirmed by density functional theoretical simulations, demonstrating that fully inorganic NCs provide an appropriate material to bridge the gap between experimental and computational studies of NCs. The presented study deepens the understanding of electronic structures in fully inorganic colloidal gold NCs and how to systematically tune their optical properties via surface charge density and particle size

    Role of Acetyl-Phosphate in Activation of the Rrp2-RpoN-RpoS Pathway in Borrelia burgdorferi

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    Borrelia burgdorferi, the Lyme disease spirochete, dramatically alters its transcriptome and proteome as it cycles between the arthropod vector and mammalian host. During this enzootic cycle, a novel regulatory network, the Rrp2-RpoN-RpoS pathway (also known as the σ54–σS sigma factor cascade), plays a central role in modulating the differential expression of more than 10% of all B. burgdorferi genes, including the major virulence genes ospA and ospC. However, the mechanism(s) by which the upstream activator and response regulator Rrp2 is activated remains unclear. Here, we show that none of the histidine kinases present in the B. burgdorferi genome are required for the activation of Rrp2. Instead, we present biochemical and genetic evidence that supports the hypothesis that activation of the Rrp2-RpoN-RpoS pathway occurs via the small, high-energy, phosphoryl-donor acetyl phosphate (acetyl∼P), the intermediate of the Ack-Pta (acetate kinase-phosphate acetyltransferase) pathway that converts acetate to acetyl-CoA. Supplementation of the growth medium with acetate induced activation of the Rrp2-RpoN-RpoS pathway in a dose-dependent manner. Conversely, the overexpression of Pta virtually abolished acetate-induced activation of this pathway, suggesting that acetate works through acetyl∼P. Overexpression of Pta also greatly inhibited temperature and cell density-induced activation of RpoS and OspC, suggesting that these environmental cues affect the Rrp2-RpoN-RpoS pathway by influencing acetyl∼P. Finally, overexpression of Pta partially reduced infectivity of B. burgdorferi in mice. Taken together, these findings suggest that acetyl∼P is one of the key activating molecule for the activation of the Rrp2-RpoN-RpoS pathway and support the emerging concept that acetyl∼P can serve as a global signal in bacterial pathogenesis

    Borrelia burgdorferi Requires the Alternative Sigma Factor RpoS for Dissemination within the Vector during Tick-to-Mammal Transmission

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    While the roles of rpoSBb and RpoS-dependent genes have been studied extensively within the mammal, the contribution of the RpoS regulon to the tick-phase of the Borrelia burgdorferi enzootic cycle has not been examined. Herein, we demonstrate that RpoS-dependent gene expression is prerequisite for the transmission of spirochetes by feeding nymphs. RpoS-deficient organisms are confined to the midgut lumen where they transform into an unusual morphotype (round bodies) during the later stages of the blood meal. We show that round body formation is rapidly reversible, and in vitro appears to be attributable, in part, to reduced levels of Coenzyme A disulfide reductase, which among other functions, provides NAD+ for glycolysis. Our data suggest that spirochetes default to an RpoS-independent program for round body formation upon sensing that the energetics for transmission are unfavorable

    Role of NADPH Oxidase versus Neutrophil Proteases in Antimicrobial Host Defense

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    NADPH oxidase is a crucial enzyme in mediating antimicrobial host defense and in regulating inflammation. Patients with chronic granulomatous disease, an inherited disorder of NADPH oxidase in which phagocytes are defective in generation of reactive oxidant intermediates (ROIs), suffer from life-threatening bacterial and fungal infections. The mechanisms by which NADPH oxidase mediate host defense are unclear. In addition to ROI generation, neutrophil NADPH oxidase activation is linked to the release of sequestered proteases that are posited to be critical effectors of host defense. To definitively determine the contribution of NADPH oxidase versus neutrophil serine proteases, we evaluated susceptibility to fungal and bacterial infection in mice with engineered disruptions of these pathways. NADPH oxidase-deficient mice (p47phox−/−) were highly susceptible to pulmonary infection with Aspergillus fumigatus. In contrast, double knockout neutrophil elastase (NE)−/−×cathepsin G (CG)−/− mice and lysosomal cysteine protease cathepsin C/dipeptidyl peptidase I (DPPI)-deficient mice that are defective in neutrophil serine protease activation demonstrated no impairment in antifungal host defense. In separate studies of systemic Burkholderia cepacia infection, uniform fatality occurred in p47phox−/− mice, whereas NE−/−×CG−/− mice cleared infection. Together, these results show a critical role for NADPH oxidase in antimicrobial host defense against A. fumigatus and B. cepacia, whereas the proteases we evaluated were dispensable. Our results indicate that NADPH oxidase dependent pathways separate from neutrophil serine protease activation are required for host defense against specific pathogens

    GABAA-Mediated Inhibition Modulates Stimulus-Specific Adaptation in the Inferior Colliculus

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    The ability to detect novel sounds in a complex acoustic context is crucial for survival. Neurons from midbrain through cortical levels adapt to repetitive stimuli, while maintaining responsiveness to rare stimuli, a phenomenon called stimulus-specific adaptation (SSA). The site of origin and mechanism of SSA are currently unknown. We used microiontophoretic application of gabazine to examine the role of GABAA-mediated inhibition in SSA in the inferior colliculus, the midbrain center for auditory processing. We found that gabazine slowed down the process of adaptation to high probability stimuli but did not abolish it, with response magnitude and latency still depending on the probability of the stimulus. Blocking GABAA receptors increased the firing rate to high and low probability stimuli, but did not completely equalize the responses. Together, these findings suggest that GABAA-mediated inhibition acts as a gain control mechanism that enhances SSA by modifying the responsiveness of the neuron

    Multiple Loci Are Associated with White Blood Cell Phenotypes

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    White blood cell (WBC) count is a common clinical measure from complete blood count assays, and it varies widely among healthy individuals. Total WBC count and its constituent subtypes have been shown to be moderately heritable, with the heritability estimates varying across cell types. We studied 19,509 subjects from seven cohorts in a discovery analysis, and 11,823 subjects from ten cohorts for replication analyses, to determine genetic factors influencing variability within the normal hematological range for total WBC count and five WBC subtype measures. Cohort specific data was supplied by the CHARGE, HeamGen, and INGI consortia, as well as independent collaborative studies. We identified and replicated ten associations with total WBC count and five WBC subtypes at seven different genomic loci (total WBC count—6p21 in the HLA region, 17q21 near ORMDL3, and CSF3; neutrophil count—17q21; basophil count- 3p21 near RPN1 and C3orf27; lymphocyte count—6p21, 19p13 at EPS15L1; monocyte count—2q31 at ITGA4, 3q21, 8q24 an intergenic region, 9q31 near EDG2), including three previously reported associations and seven novel associations. To investigate functional relationships among variants contributing to variability in the six WBC traits, we utilized gene expression- and pathways-based analyses. We implemented gene-clustering algorithms to evaluate functional connectivity among implicated loci and showed functional relationships across cell types. Gene expression data from whole blood was utilized to show that significant biological consequences can be extracted from our genome-wide analyses, with effect estimates for significant loci from the meta-analyses being highly corellated with the proximal gene expression. In addition, collaborative efforts between the groups contributing to this study and related studies conducted by the COGENT and RIKEN groups allowed for the examination of effect homogeneity for genome-wide significant associations across populations of diverse ancestral backgrounds
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