Dimensions and models of contemporary public space management in England

This article discusses the concept of public space management and its evolution in a context of wider changes to urban governance. Public space management is taken as a sphere of urban governance in which conflicting societal demands on, and aspirations for, public space are interpreted through a set of processes and practices. Four interlinked dimensions for public space management are proposed: the co-ordination of interventions; the regulation of uses and conflicts between uses; the definition and deployment of maintenance routines; and investment in public spaces and their services. Within this conceptual framework, the paper looks at recent changes in public space management in England to suggest the emergence of alternative models of management. These are based on the roles ascribed to the state, to private agents and to user organisations, and on different approaches to dealing with the four management dimensions. Although the discussion shows that these models are more than just abstract formulations, and have been used to deal with a variety of public space problems, an important purpose for the paper is to provide an analytical framework through which to examine emergent practices in the management of public space and their potential consequences.     

Organic aerosol source apportionment from highly time-resolved molecular composition measurements

Organic molecular composition measurements with 3.5 min time resolution were performed with the photoionization aerosol mass spectrometer (PIAMS) over an 18-day period in October–November 2007 in Wilmington, Delaware, USA. Mass spectra were obtained for a total of 6244 time periods, and the signal intensities of 60 specific m/z ratios corresponding to key organic molecular species were modeled by positive matrix factorization (PMF). Six factors were identified that could be tentatively linked to specific sources (diesel exhaust, car emissions/road dust, meat cooking) or types of compounds (alkanes/alkanoic acids, phthalates, PAHs). Owing to the inherent high time resolution of PIAMS, the temporal (diurnal) and wind direction dependencies of these factors could be examined in detail to assess the impacts of point sources and atmospheric processes. Time-resolved EC/OC and gas-phase data (O₃, NO_x, CO) were also obtained during the measurement period to help distinguish primary (POC) and secondary (SOC) organic carbon. The total organic carbon (TOC) concentration averaged 2.6 μg m^?3 during the measurement period and most (>90%) was classified as primary. Of this, approximately one-third could be assigned as combustion POC and the other two-thirds as non-combustion POC. The PMF results were combined with EC/OC data for source apportionment. The diesel and car/road dust factors together represented about two-thirds of TOC, while the alkane/alkanoic acid and meat cooking factors contributed most of the remaining one-third. The phthalate and PAH factors contributed very little, only a few percent of the total. The diesel factor correlated most strongly to combustion POC, while the sum of the remaining factors correlated well with non-combustion POC.     

Perceptions of climate change on the Island of Providencia

Climate change-related impacts have the capacity to substantially influence Small Island Developing States (SIDS) in the Caribbean. Currently, many SIDS are engaged in large-scale vulnerability assessments that aim to identify, analyse, and inform solutions to mitigate climate change-related impacts. Many of these assessments, while useful, place little emphasis on the local stakeholders' perceptions of climate change. One such Caribbean community impacted by climate-related change is Providence Island in Colombia. Using a vulnerability assessment framework (Marshall, P.A. et al. 2010. A framework for social adaptation to climate change: sustaining tropical coastal communities and industries. Gland: IUCN Publication Services), researchers interviewed island residents (N = 23) about their perceptions of climate change, impacts on the local environment, and how the island community may adapt. All interviews were transcribed and analysed using a priori and open coding to identify patterns of and relationships between stakeholders' responses. Results indicate that local perceptions of climate change are linked to (1) environmental knowledge, (2) environmental awareness, attitudes, and beliefs, and (3) perceptions of risk. Implications for local adaptive strategies, education, communication, and suggestions for engagement at the local level are discussed.     

Sea Cucumber Aquaculture in the Western Indian Ocean: Challenges for Sustainable Livelihood and Stock Improvement

The decline in sea cucumber fisheries that serve the Asian dried seafood market has prompted an increase in global sea cucumber aquaculture. The tropical sandfish (Holothuria scabra) has, in this context, been reared and produced with mixed success. In the Western Indian Ocean, villagers often participate in the export fishery for sea cucumbers as a source of income. However, with a growing concern of depleted stocks introduction of hatcheries to farm sandfish as a community livelihood and to replenish wild stocks is being promoted. This review identifies and discusses a number of aspects that constitute constraints or implications with regard to development of sandfish farming in the region. The conclusion is that for sandfish farming to live up to its expectations the possible impacts need to be further studied, and that improved evaluation of ongoing projects is required. In the interim, a precautionary approach toward new enterprise activities is suggested.     

Comparative study of non-invasive methods for assessing Daphnia magna embryo toxicity

Embryos, unlike adults, are typically sessile, which allows for an increase in the available metrics that can be used to assess chemical toxicity. We investigate Daphnia magna development rate and oxygen consumption as toxicity metrics and compare them to arrested embryo development using four different techniques with potassium cyanide (KCN) as a common toxicant. The EC₅₀ (95 % CI) for arrested development was 2,535 (1,747–3,677) μg/L KCN. Using pixel intensity changes, recorded with difference imaging, we semi-quantitatively assessed a decrease in development rate at 200 μg/L KCN, threefold lower than the arrested development lowest observed effect concentration (LOEC). Respirometry and self-referencing (SR) microsensors were two unique techniques used to assess oxygen consumption. Using respirometry, an increase in oxygen consumption was found in the 5 μg/L KCN treatment and a decrease for 148 μg/L, but no change was found for the 78 μg/L KCN treatment. Whereas, with SR microsensors, we were able to detect significant changes in oxygen consumption for all three treatments: 5, 78, and 148 μg/L KCN. While SR offered the highest sensitivity, the respirometry platform developed for this study was much easier to use to measure the same endpoint. Oxygen consumption may be subject to change during the development process, meaning consumption assessment techniques may only be useful only for short-term experiments. Development rate was a more sensitive endpoint though was only reliable four of the six embryonic developmental stages examined. Despite being the least sensitive endpoint, arrested embryo development was the only technique capable of assessing the embryos throughout all developmental stages. In conclusion, each metric has advantages and limitations, but because all are non-invasive, it is possible to use any combination of the three.     

Interlaboratory and Intralaboratory Variability in the Analysis of Mercury in Coal

Abstract

With the passage of the 1990 Clean Air Act Amendments (CAAA), accurate determination of the concentration of mercury in coal has become an increasingly important issue. To address this issue, CONSOL R&D conducted a round robin analytical program to determine the interlaboratory and intralaboratory variability in the measurement of mercury in coal. CONSOL supplied homogeneous splits of Pittsburgh and Illinois #6 seam coals, and the NIST 1632b coal standard to eleven laboratories, twice each, over a one-year period. A twelfth laboratory analyzed the coals once. A European coal standard, certified for mercury, was analyzed at the completion of the round robin study to evaluate accuracy. The round robin participants included representatives from industry, government, and academia. The laboratories, which are experienced in mercury-in-coal analysis, used various state-of-the-art sample preparation and analysis procedures in the study. The round robin results indicate that a substantial level of variability exists in the mercury-in-coal determination. Earlier studies1 found similar results. The relative intralaboratory repeatability was 0.02 ppm and the relative interlaboratory reproducibility ranged from 0.04 to 0.05 ppm. The study showed that laboratory variability can be greatly skewed by outlier values. Fifty-six percent of the results for the European coal standard fell within a 95% confidence interval of the standard (0.138 ± 0.11 ppm). These results indicate that accuracy is not method-dependent.     

Characterization of particulate matter and gaseous emissions of a C-130H aircraft

The gaseous and nonvolatile particulate matter (PM) emissions of two T56-A-15 turboprop engines of a C-130H aircraft stationed at the 123rd Airlift Wing in the Kentucky Air National Guard were characterized. The emissions campaign supports the Strategic Environmental Research and Development Program (SERDP) project WP-1401 to determine emissions factors from military aircraft. The purpose of the project is to develop a comprehensive emissions measurement program using both conventional and advanced techniques to determine emissions factors of pollutants, and to investigate the spatial and temporal evolutions of the exhaust plumes from fixed and rotating wing military aircraft. Standard practices for the measurement of gaseous emissions from aircraft have been well established; however, there is no certified methodology for the measurement of aircraft PM emissions. In this study, several conventional instruments were used to physically characterize and quantify the PM emissions from the two turboprop engines. Emissions samples were extracted from the engine exit plane and transported to the analytical instrumentation via heated lines. Multiple sampling probes were used to assess the spatial variation and obtain a representative average of the engine emissions. Particle concentrations, size distributions, and mass emissions were measured using commercially available aerosol instruments. Engine smoke numbers were determined using established Society of Automotive Engineers (SAE) practices, and gaseous species were quantified via a Fourier-transform infrared-based gas analyzer. The engines were tested at five power settings, from idle to take-off power, to cover a wide range of operating conditions. Average corrected particle numbers (PNs) of (6.4-14.3) x 10(7) particles per cm3 and PN emission indices (EI) from 3.5 x 10(15) to 10.0 x 10(15) particles per kg-fuel were observed. The highest PN EI were observed for the idle power conditions. The mean particle diameter varied between 50 nm at idle to 70 nm at maximum engine power. PM mass EI ranged from 1.6 to 3.5 g/kg-fuel for the conditions tested, which are in agreement with previous T56 engine measurements using other techniques. Additional PM data, smoke numbers, and gaseous emissions will be presented and discussed.     

XANES spectroscopic analysis of phosphorus speciation in alum-amended poultry litter

Aluminum sulfate (alum; Al(2)(SO(4))(3).14H(2)O) is used as a chemical treatment of poultry litter to reduce the solubility and release of phosphate, thereby minimizing the impacts on adjacent aquatic ecosystems when poultry litter is land applied as a crop fertilizer. The objective of this study was to determine, through the use of X-ray absorption near edge structure (XANES) spectroscopy and sequential extraction, how alum amendments alter P distribution and solid-state speciation within the poultry litter system. Our results indicate that traditional sequential fractionation procedures may not account for variability in P speciation in heterogeneous animal manures. Analysis shows that NaOH-extracted P in alum amended litters is predominantly organic ( approximately 80%), whereas in the control samples, >60% of NaOH-extracted P was inorganic P. Linear least squares fitting (LLSF) analysis of spectra collected of sequentially extracted litters showed that the P is present in inorganic (P sorbed on Al oxides, calcium phosphates) and organic forms (phytic acid, polyphosphates, and monoesters) in alum- and non-alum-amended poultry litter. When determining land application rates of poultry litter, all of these compounds must be considered, especially organic P. Results of the sequential extractions in conjunction with LLSF suggest that no P species is completely removed by a single extractant. Rather, there is a continuum of removal as extractant strength increases. Overall, alum-amended litters exhibited higher proportions of Al-bound P species and phytic acid, whereas untreated samples contained Ca-P minerals and organic P compounds. This study provides in situ information about P speciation in the poultry litter solid and about P availability in alum- and non-alum-treated poultry litter that will dictate P losses to ground and surface water systems.