Relationship between continuous aerosol measurements and firn core chemistry over a 10-year period at the South Pole

Before ice core chemistry can be used to estimate past atmospheric chemistry it is necessary to establish an unambiguous link between concentrations of chemical species in the air and snow. For the first time a continuous long-term record of aerosol properties (aerosol light scattering coefficient, σsp, and Ångström exponent, å) at the South Pole are compared with the chemical record from a high resolution firn core (∼10 samples per year) covering the period from 1981 to 1991. Seasonal signals in å, associated with winter minima due to coarse mode seasalt and summer maxima due to accumulation mode sulfate aerosol, are reflected in the firn core SO42−/Na+ concentration ratio. Summertime ratios of σsp and aerosol optical depth, τ to corresponding firn core sulfur concentrations are determined and the ‘calibrations’ are applied to sulfur concentrations in snowpits from a previous study. Results show that σsp estimates from snowpit sulfur concentrations are in agreement with atmospheric measurements while τ estimates are significantly different, which is likely due to the lack of understanding of the processes that mix surface air with air aloft

Relationship between Continuous Aerosol Measurements and Firn Core Chemistry over a 10‐year Period at the South Pole

Before ice core chemistry can be used to estimate past atmospheric chemistry it is necessary to establish an unambiguous link between concentrations of chemical species in the air and snow. For the first time a continuous long‐term record of aerosol properties (aerosol light scattering coefficient, σsp , and Ångström exponent, å) at the South Pole are compared with the chemical record from a high resolution firn core (∼10 samples per year) covering the period from 1981 to 1991. Seasonal signals in å, associated with winter minima due to coarse mode seasalt and summer maxima due to accumulation mode sulfate aerosol, are reflected in the firn core SO42−/Na+ concentration ratio. Summertime ratios of σsp and aerosol optical depth, τ to corresponding firn core sulfur concentrations are determined and the ‘calibrations’ are applied to sulfur concentrations in snowpits from a previous study. Results show that σsp estimates from snowpit sulfur concentrations are in agreement with atmospheric measurements while τ estimates are significantly different, which is likely due to the lack of understanding of the processes that mix surface air with air aloft

High dimensional decision dilemmas in climate models

An important source of uncertainty in climate models is linked to the calibration of model parameters. Interest in systematic and automated parameter optimization procedures stems from the desire to improve the model climatology and to quantify the average sensitivity associated with potential changes in the climate system. Building upon on the smoothness of the response of an atmospheric circulation model (AGCM) to changes of four adjustable parameters, Neelin et al. (2010) used a quadratic metamodel to objectively calibrate the AGCM. The metamodel accurately estimates global spatial averages of common fields of climatic interest, from precipitation, to low and high level winds, from temperature at various levels to sea level pressure and geopotential height, while providing a computationally cheap strategy to explore the influence of parameter settings. Here, guided by the metamodel, the ambiguities or dilemmas related to the decision making process in relation to model sensitivity and optimization are examined. Simulations of current climate are subject to considerable regional-scale biases. Those biases may vary substantially depending on the climate variable considered, and/or on the performance metric adopted. Common dilemmas are associated with model revisions yielding improvement in one field or regional pattern or season, but degradation in another, or improvement in the model climatology but degradation in the interannual variability representation. Challenges are posed to the modeler by the high dimensionality of the model output fields and by the large number of adjustable parameters. The use of the metamodel in the optimization strategy helps visualize trade-offs at a regional level, e.g., how mismatches between sensitivity and error spatial fields yield regional errors under minimization of global objective functions

Nonnative \u3ci\u3ePhragmites australis\u3c/i\u3e Invasion into Utah Wetlands

Phragmites australis (Cav.) Trin. ex Steud. (common reed), already one of the world’s most widespread plant species, has realized rapid range expansion in coastal wetlands of North America in the past century, but little is known about P. australis range expansion in inland wetland systems. We used genetic analyses, aerial photographs, field surveys, and a greenhouse experiment to study the extent and mechanism of nonnative P. australis invasion of Utah wetlands. We collected and genetically analyzed 39 herbarium samples across the state and 225 present-day samples from northern Utah’s major wetland complexes. All samples collected before 1993 and all samples collected outside the major wetlands of northern Utah, including some as recent as 2001, were identified as native (haplotypes A, B, D, and H). Only 10 (4%) of the present-day samples were native, each from small, discrete, low-density stands; the remaining samples were nonnative (haplotype M). Our earliest nonnative sample was collected near the Great Salt Lake in 1993. Around the Great Salt Lake, which contains 40% of Utah’s wetlands, P. australis cover has increased from 20% to 56% over the past 27 years—an increase that appears attributable to the nonnative strain. In a 3-month-long greenhouse experiment, the nonnative haplotype grew taller, had more aboveground biomass, and had a greater above- to belowground biomass ratio than the native haplotypes regardless of nitrogen, phosphorus, or water availability. Nonnative P. australis is rapidly invading the wetlands of northern Utah. Areas in Utah where the native P. australis remains should be identified and protected

A 12,000 Year Record of Explosive Volcanism in the Siple Dome Ice Core, West Antarctica

Air mass trajectories in the Southern Hemisphere provide a mechanism for transport to and deposition of volcanic products on the Antarctic ice sheet from local volcanoes and from tropical and subtropical volcanic centers. This study extends the detailed record of Antarctic, South American, and equatorial volcanism over the last 12,000 years using continuous glaciochemical series developed from the Siple Dome A (SDMA) ice core, West Antarctica. The largest volcanic sulfate spike ( 280 mu g/L) occurs at 5881 B. C. E. Other large signals with unknown sources are observed around 325 B. C. E. ( 270 mu g/L) and 2818 B. C. E. ( 191 mu g/L). Ages of several large equatorial or Southern Hemisphere volcanic eruptions are synchronous with many sulfate peaks detected in the SDMA volcanic ice chemistry record. The microprobe fingerprinting\u27\u27 of glass shards in the SDMA core points to the following Antarctic volcanic centers as sources of tephra found in the SDMA core: Balenny Island, Pleiades, Mount Berlin, Mount Takahe, and Mount Melbourne as well as Mount Hudson and possibly Mount Burney volcanoes of South America. Identified volcanic sources provide an insight into the poorly resolved transport history of volcanic products from source volcanoes to the West Antarctic ice sheet

Increasing Efforts to Reduce Cervical Cancer through State-Level Comprehensive Cancer Control Planning

Reducing cervical cancer disparities in the U.S. requires intentional focus on structural barriers such as systems and policy which impact access to human papillomavirus (HPV) vaccination, cervical cancer screening and treatment. Such changes are difficult and often politicized. State comprehensive cancer control (CCC) plans are vehicles that, if designed well, can help build collective focus on structural changes. Study objectives were to identify the prioritization of cervical cancer in state CCC plans, the conceptualization of HPV within these plans, and the focus of plans on structural changes to reduce cervical cancer disparities. Data were gathered by systematic content analysis of CCC plans from 50 states and the District of Columbia from February-June 2014 for evidence of cervical cancer prioritization, conceptualization of HPV, and focus on structural barriers to cervical cancer vaccination, screening or treatment. Findings indicate that prioritization of cervical cancer within state CCC plans may not be a strong indicator of state efforts to reduce screening and treatment disparities. While a majority of plans reflected scientific evidence that HPV causes cervical and other cancers, they did not focus on structural elements impacting access to evidence-based interventions. Opportunities exist to improve state CCC plans by increasing their focus on structural interventions that impact cervical cancer prevention, detection, and treatmentparticularly for the 41% of plans ending in 2015 and the 31% ending between 2016-2020. Future studies should focus on the use of policy tools in state CCC plans and their application to cervical cancer prevention and treatment

Liminal Roles as a Source of Creative Agency in Management: The Case of Knowledge-Sharing Communities

Studies suggest that the experience of liminality – of being in an ambiguous, ‘betwixt and between’ position – has creative potential for organizations. We contribute to theory on the link between liminality and creative agency through a study of the coordinators of ‘knowledge-sharing communities’; one of the latest examples of a ‘neo-bureaucratic’ practice that seeks to elicit innovative responses from employees while intensifying control by the organization. Through a role-centred perspective, our study found that both the structural and interpretive aspects of coordinators’ role enactments promoted a degree of creative agency. ‘Front-stage’ and ‘back-stage’ activities were developed to meet the divergent expectations posed by senior management and community members, and the ambiguity of their roles prompted an array of different role interpretations. Our findings contribute to theory by showing how the link between liminality and creative agency is not confined to roles and spaces (consultancy work, professional expertise) that are positioned across organizational boundaries, or free from norms and expectations, but may also apply to roles that are ambiguously situated within organizational contexts and which are subject to divergent expectations. This shows how neo-bureaucratic forms may be both reproduced and renewed through the creative responses of individual managers

IPBES Invasive Alien Species Assessment: Summary for Policymakers

Summary for Policymakers of the Thematic Assessment Report on Invasive Alien Species and their Control of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services

Nuclear Factor I/B is an Oncogene in Small Cell Lung Cancer

Small cell lung cancer (SCLC) is an aggressive cancer often diagnosed after it has metastasized. Despite the need to better understand this disease, SCLC remains poorly characterized at the molecular and genomic levels. Using a genetically engineered mouse model of SCLC driven by conditional deletion of Trp53 and Rb1 in the lung, we identified several frequent, high-magnitude focal DNA copy number alterations in SCLC. We uncovered amplification of a novel, oncogenic transcription factor, Nuclear factor I/B (Nfib), in the mouse SCLC model and in human SCLC. Functional studies indicate that NFIB regulates cell viability and proliferation during transformation.National Cancer Institute (U.S.) (grant P30-CA14051)David H. Koch Institute for Integrative Cancer Research at MIT (Ludwig Center for Molecular Oncology)Howard Hughes Medical InstituteAlfred P. Sloan Foundation (Research Fellowship)International Association for the Study of Lung Cance