General aviation piston-engine exhaust emission reduction

To support the promulgation of aircraft regulations, two airports were examined, Van Nuys and Tamiami. It was determined that the carbon monoxide (CO) emissions from piston-engine aircraft have a significant influence on the CO levels in the ambient air in and around airports, where workers and travelers would be exposed. Emissions standards were set up for control of emissions from aircraft piston engines manufactured after December 31, 1979. The standards selected were based on a technologically feasible and economically reasonable control of carbon monoxide. It was concluded that substantial CO reductions could be realized if the range of typical fuel-air ratios could be narrowed. Thus, improvements in fuel management were determined as reasonable controls

Seawater carbonate chemistry and skeletal density of hardground-forming high-latitude Crustose Coralline Algae

Crustose coralline algae (CCA) function as foundation species by creating marine carbonate hardground habitats. High‐latitude species may be vulnerable to regional warming and acidification. Here, we report the results of an experiment investigating the impacts of CO2‐induced acidification (pCO2 350, 490, 890, 3200 µatm) and temperature (6.5, 8.5, 12.5°C) on the skeletal density of two species of high‐latitude CCA: Clathromorphum compactum (CC) and C. nereostratum (CN). Skeletal density of both species significantly declined with pCO2. In CN, the density of previously deposited skeleton declined in the highest pCO2 treatment. This species was also unable to precipitate new skeleton at 12.5°C, suggesting that CN will be particularly sensitive to future warming and acidification. The decline in skeletal density exhibited by both species under future pCO2 conditions could reduce their skeletal strength, potentially rendering them more vulnerable to disturbance, and impairing their production of critical habitat in high‐latitude systems

Seawater carbonate chemistry and survival, calcification rate of 4 species of coral over a 93-day ocean acidification and warming laboratory experiment

We conducted a 93-day experiment investigating the independent and combined effects of acidification (280−3300 µatm pCO2) and warming (28°C and 31°C) on calcification and linear extension rates of four key Caribbean coral species (Siderastrea siderea, Pseudodiploria strigosa, Porites astreoides, Undaria tenuifolia) from inshore and offshore reefs on the Belize Mesoamerican Barrier Reef System. All species exhibited nonlinear declines in calcification rate with increasing pCO2. Warming only reduced calcification in Ps. strigosa. Of the species tested, only S. siderea maintained positive calcification in the aragonite-undersaturated treatment. Temperature and pCO2 had no effect on the linear extension of S. siderea and Po. astreoides, and natal reef environment did not impact any parameter examined. Results suggest that S. siderea is the most resilient of these corals to warming and acidification owing to its ability to maintain positive calcification in all treatments, Ps. strigosa and U. tenuifolia are the least resilient, and Po. astreoides falls in the middle. These results highlight the diversity of calcification responses of Caribbean corals to projected global change

Keystone predators govern the pathway and pace of climate impacts in a subarctic marine ecosystem

Predator loss and climate change are hallmarks of the Anthropocene yet their interactive effects are largely unknown. Here, we show that massive calcareous reefs, built slowly by the alga Clathromorphum nereostratum over centuries to millennia, are now declining because of the emerging interplay between these two processes. Such reefs, the structural base of Aleutian kelp forests, are rapidly eroding because of overgrazing by herbivores. Historical reconstructions and experiments reveal that overgrazing was initiated by the loss of sea otters, Enhydra lutris (which gave rise to herbivores capable of causing bioerosion), and then accelerated with ocean warming and acidification (which increased per capita lethal grazing by 34 to 60% compared with preindustrial times). Thus, keystone predators can mediate the ways in which climate effects emerge in nature and the pace with which they alter ecosystems

Corporate governance crisis down under: Post-Enron accounting education and research inertia

Abstract Australian and New Zealand accounting academic responses to corporate governance and reporting failures is a story not simply told in the context of high profile international corporate failures such as Enron and WorldCom. This study notes a sequence of major Australian corporate failures that predate Enron and WorldCom. Through research into professional, business and research literature, profession and governmental/regulatory websites, and interviews with senior accounting academics across Australia and New Zealand, it also highlights a tale of limited response by Australian and New Zealand accounting academics and investigates the manifest and latent drivers of this inertia. The corporatisation and commercialisation of universities and related governance processes emerge as root causes of accounting academics' general failure to address recent major breakdowns in corporate governance and reporting in the business world. The paper closes by reviewing opportunities for change in an otherwise embattled environment.Corporate failures, accounting education, corporate governance, accounting academics, teaching, curricula,

The Role of Ligands on the Equilibria Between Functional States of a G Protein-Coupled Receptor

G protein-coupled receptors (GPCRs) exhibit a wide variety of signaling behaviors in response to different ligands. Using a small label on the cytosolic interface of TM6 (Cys-265), (19)F NMR spectra of the β(2) adrenoreceptor, β(2)AR, reconstituted in maltose–neopentyl glycol detergent micelles, revealed two distinct inactive states, an activation intermediate state en route to activation, and, in the presence of a G protein mimic, a predominant active state. An analysis of spectra as a function of temperature reveals that for all ligands, the activation intermediate is entropically favored and enthalpically disfavored. β(2)AR enthalpy changes toward activation are notably lower than those observed with rhodopsin – a likely consequence of basal activity and the fact that the ionic lock and other interactions stabilizing the inactive state of β(2)AR, are weaker. Positive entropy changes toward activation likely reflect greater mobility (configurational entropy) in the cytoplasmic domain, confirmed through an order parameter analysis. Ligands greatly influence overall changes in enthalpy and entropy of the system and corresponding changes in population and amplitude of motion of given states, suggesting a complex landscape of states and substates