Creating cultural change @ campus kindergarten: The sustainable planet project

This article highlights how the Campus Kindergarten community has confronted the challenge of sustainability. It has done this by creating a ‘learning organisation’ where a culture of sustainability is continuously recreated by taking advantage of, rather than resisting, the natural power of complexity. This centre is a model of quality early childhood education for sustainability

Changes in benthic ecosystem properties and functions across sedimentary gradients in estuaries

In estuaries, sediment properties dominate the inhabiting flora and fauna and their role in energy flows and nutrient cycling. Whilst sediment transport is a natural, key process, human intervention in estuaries and their catchments has altered the regime of terrigenous sediment loading and pose both short and long-term consequences to ecosystem functioning. Temporary increases in turbidity reduce light availability for primary production by microphytobenthos (MPB) that fuel benthic communities. Long-term alteration of grain size properties changes the distribution of key macrofaunal species and how they interact with their environment, carrying potentially serious implications for the ecological functioning of these systems. Our knowledge of how benthic ecosystems respond to changes in sedimentary regimes is crucial to our ability to project and manage the impacts of environmental change. In this thesis, I investigated the multifaceted effects of increased sediment loading on the benthic biota and their functioning using natural and experimental sedimentary gradients. An in situ experiment was conducted on an intertidal sandflat to examine the effects of short-term increases in suspended sediment concentration (SSC) on benthic autotrophic (primary production) and heterotrophic processes. In sunlit conditions, increases in SSC led to dramatic declines in net primary production and concomitant increases in NH₄⁺ efflux from the sediment to the water column. Although sediment chlorophyll-⍺ concentration increased with higher levels of SSC, a result that was likely a photoadaptive response to reduced light intensity, SSC reduced O₂ production per unit of chlorophyll -⍺ . SSC had no significant effect on sediment properties or heterotrophic processes such as sediment oxygen consumption or nutrient efflux, suggesting that temporary increases in suspended sediments (within the range of SSC tested) primarily affected photosynthetic processes. Sediment properties, macrofaunal diversity and biogeochemical fluxes were measured across natural gradients of silt and clay (hereafter mud) to determine the effects of habitat change associated with chronic sediment loading on the structure and functioning of benthic communities. There were significant declines in measures of macrofaunal diversity and the maximum densities of key bioturbating bivalves (Austrovenus stutchburyi and Macomona liliana) with increased mud content. Concurrently, the maximum rates of sediment oxygen consumption (SOC), NH₄⁺ efflux (a proxy of nutrient regeneration)and biomass standardised gross primary production (GPPChl-⍺) also decreased with increasing mud content. A. stutchburyi contributed disproportionately to variation in SOC and NH₄⁺ efflux, suggesting that losses of strongly interacting key species concomitant with increased sediment mud content could have a significant impact on ecosystem function. The results from this study demonstrate the significant loss of ecosystem function in intertidal sandflats that is likely from increased sediment mud content associated with long-term increases in sedimentation stress. The spatial distributions of MPB biomass, macrofaunal grazer abundances and deposit feeding activity were measured across a gradient of sediment mud content to determine relationships between grazers and MPB biomass across transitional sedimentary environments. The density of feeding traces produced by M. Liliana was measured as a proxy of deposit feeding activity by this species. MPB biomass was generally lower in areas with higher deposit feeding activity but this relationship was scale dependent, emerging over larger areas (tens of centimetres) but absent at local (centimetre) scales relative to the animal’s feeding ambit. Despite higher MPB biomass in muddy sediments, feeding trace density was markedly lower, suggesting lower feeding activity and trophic exchange in muddy compared with sandy sediments. The suspension feeding bivalve A. stutchburyi was positively associated with MPB biomass and the interaction between A. stutchburyi density and mud was the strongest predictor of MPB biomass. Thus, non-trophic interactions that potentially facilitate production may override the deleterious effects of grazing on MPB biomass by large macrofaunal species. This thesis demonstrates the high capacity of sandflat systems for primary, secondary production and nutrient regeneration and the degradation of these ecological properties and functions in muddier and more turbid systems. The decline in this functional capacity reflects the alterations of multiple ecological components and their interactions corresponding to habitat change. Defining changes in these interaction networks can improve our ability to track changes in ecosystem functioning and elucidate underlying pathways and potential mechanisms. In particular, this thesis highlights the value of observing changes in these ecological properties and functions across natural and experimental gradients at the appropriate scales in time and space over which stressors operate

The Low Temperature Surface Geochemistry And Kinetics Of Pyrrhotite Weathering: Influences On Acid Mine Drainage (amd)

Investigations were conducted into the mechanisms of pyrrhotite oxidation and dissolution. Analysis of pyrrhotite (Fe{dollar}\rm\sb7S\sb8{dollar}) near surfaces (50A) identifies 32% Fe(III) and 68% Fe(II), both bonded to sulphide. These results show pyrrhotite has the stoichiometry Fe(III){dollar}\sb2{dollar}Fe(II){dollar}\rm\sb5S\sb8{dollar}.;Air oxidized pyrrhotite surfaces are compositionally zoned. The outermost surface layer is Fe(III)-oxyhydroxide, below which exists an Fe-deficient, S-rich layer that displays a continuous, gradual decrease in S/Fe until that of the unaltered pyrrhotite. Compositional zones develop by electron and iron migration along a sequence of metal vacancies. At the surface, Fe(III)-oxyhydroxides form through reaction with adsorbed oxygen and hydroxyl species.;Pyrrhotite reacted in {dollar}\rm H\sb2SO\sb4{dollar} (pH 3.0) develops Fe(III)-oxyhydroxide coated surfaces. Desiccation results in Fe(III)-oxyhydroxide spalling and exposure of underlayers containing enhanced S/Fe ratios. Pyrrhotite surfaces reacted in HCl-{dollar}\rm H\sb2SO\sb4{dollar} acid mixtures (pH 3.0) are S-rich and Fe-deficient, with minimal amounts of Fe(III)-oxyhydroxide. Suppression of Fe(III)-oxyhydroxides is attributed to interactions from chloride ions.;Iron concentrations measured in HCl-{dollar}\rm H\sb2SO\sb4{dollar} mixtures (pH 3.0) give linear trends when plotted as a function of the square-root of time, indicating diffusion limited dissolution. Sulphate concentrations remain constant at 1.0 mg/L and iron is 95% ferrous, demonstrating dissolution proceeds incongruently with respect to both iron and sulphur species. A 2:1 removal-release relationship between H{dollar}\sp+{dollar} and Fe{dollar}\sp{lcub}2+{rcub}{dollar} provides mass balance evidence that dissolution proceeds via ion exchange. Calculated activation energies are approximately 25 kJ/mol, indicating that pyrrhotite dissolution is limited by Fe diffusion into bulk solution.;Pyrrhotite and magnetite XRD patterns from the Mattabi Mine tailings yield anomalous peaks. Intense pressures and stresses associated with milling are found to increase the potential for mineral oxidation through development of magnetite (100) cleavages and conversion of monoclinic pyrrhotite to hexagonal pyrrhotite. Surface analysis of coatings on pyrrhotite collected from the Mattabi tailings unsaturated and saturated zones shows Fe(OH){dollar}\sb3{dollar} as the dominant unsaturated zone secondary phase and that FeOOH is the prevailing saturated zone phase. Fe(III) sulphate salts form in the capillary fringe immediately above the water table

The Conscience of Virginia: Judge Robert R. Merhige, Jr., and the Politics of School Desegregation

The United States Supreme Court’s 1954 landmark decision in Brown v. Board of Education declared that segregation in public education violated the Fourteenth Amendment to the United States Constitution. For the millions of African Americans who had endured decades of separate and unequal schooling, this decision was a resounding reaffirmation of the nation’s commitment to equal justice under the law. But those who expected segregated schools to end overnight were in for a rude awakening. The National Association for the Advancement of Colored People (“NAACP”), which had led the legal assault against segregation since its founding in 1909, was encouraged by the Court’s ruling. But its attorneys would soon realize that their initial optimism had been premature and that they had greatly underestimated white southern resistance. Perhaps few could have predicted that it would take nearly twenty years before school desegregation would begin in earnest in the states of the former Confederacy— and only then because of the determined actions of a few courageous judges willing to place principle above prejudice. Judge Robert R. Merhige, Jr., of Virginia was one of them

Whither the Disability Rights Movement?

While reading this book in 2010, almost twenty years to the date after President George H.W. Bush signed the Americans with Disability Act ( ADA ), one realizes how much the world of politics has changed. It is difficult to remember a time when such major legislation passed the U.S. Senate by a vote of 91 to 6 and the House of Representatives by 377 to 28. Even more surprising, as we look back to 1990, is the fact that the executive branch was controlled by a different political party than the legislative branch. Contrast this legislative record with the milieu surrounding the health care reform legislation of 2010 and the economic stimulus bill of 2009, and the overwhelming bipartisan vote on the ADA seems quite remarkable. This unique legislative history provides the context for Professor Bagenstos\u27s new book, Law and the Contradictions of the Disability Rights Movement. In his book, Bagenstos traces how the often-diverging strands of the disability rights movement coalesced to create change, and how the diversity of the movement is now inhibiting future change. In short, Bagenstos\u27s book is about the contradictions and tensions within the disability rights movement and the law it forged. His analysis and conclusions are very insightful and appear to be drawn from both his numerous articles on the subject and his experience in the movement, including arguing several significant ADA cases before the Supreme Court. Indeed, while there are many aspects of Bagenstos\u27s book that make it worth reading, his analysis of the movement\u27s core contradiction, its history, and its ongoing impact are particularly helpful, even to those who have already had significant exposure to the ADA

Pure nuclear quadrupole resonance determination of the electric field gradient asymmetry for broad lines (and application to YBa2Cu3O7)

We present an angle dependent nuclear quadrupole resonance (ADNQR) method to determine the electric field gradient asymmetry parameter eta in systems where the resonance line is so broad that the radio frequency field can excite only a portion of the nuclear spins. In this situation the recently developed spectroscopic methods are not applicable. ADNQR is useful for single crystals and oriented powders, and, for small eta determines eta^4. Therefore, it can be used to evaluate fluctuations in eta due to inhomogeneities. We demonstrate the application of ADNQR experimentally to oriented superconducting YBa2Cu3O7 powder.Comment: 5 pages, 3 figure