The hydrothermal reaction kinetics of aspartic acid

Experimental data on the hydrothermal reaction kinetics of aspartic acid were acquired using a custom-built spectrophotometric reaction cell which permits in situ observation under hydrothermal conditions. The results of this study indicate that the reaction kinetics of dilute aspartic acid solutions are significantly different depending on the presence or absence of catalytic surfaces such as standard metal alloys. The spectroscopic data presented here represent the first direct observations, in situ and in real time, of an amino acid reacting in a hydrothermal solution. Quantitative kinetic information, including rate constants, concentration versus time profiles, and calculations of the individual component spectra, was obtained from the data using a chemometric approach based on factor analysis/principle component analysis which treats the rate expressions simultaneously as a system of differential algebraic equations (DAE) of index 1. Identification of the products was confirmed where possible by high pressure anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). The reaction kinetics of aspartic acid under hydrothermal conditions was observed to be highly complex, in contrast to previous studies which indicated almost exclusively deamination. At lower temperatures (120-170 °C), several different reaction pathways were observed, including decarboxylation and polymerization, and the catalytic effects of reactor surfaces on the aspartic acid system were clearly demonstrated. At higher temperatures (above 170 °C), aspartic acid exhibited highly complex behaviour, with evidence indicating that it can simultaneously dimerize and cyclize, deaminate (by up to two pathways), and decarboxylate (by up to two pathways). These higher temperature kinetics were not fully resolvable in a quantitative manner due to the complexity of the system and the constraints of UV spectroscopy. The results of this study provide strong evidence that the reaction kinetics of aspartic acid are very sensitive to parameters such as temperature, reactor materials (i.e., reactive surfaces), and additives, and that previous observations on aspartic acid were specific to the choice of experimental conditions.     

Development of a coral cDNA array to examine gene expression profiles in Montastraea faveolata exposed to environmental stress

The development of a cDNA array of coral genes and its application to investigate changes in coral gene expression associated with stressful conditions is described. The array includes both well-characterized and previously unidentified coral genes from Acropora cervicornis and Montastraea faveolata. Corals were exposed to either natural or anthropogenic stressors to elicit the expression of stress genes for isolation and incorporation onto the array. A total of 32 genes involved in protein synthesis, apoptosis, cell signaling, metabolism, cellular defense and inflammation were included on the array. Labeled cDNA from coral (Montastraea faveolata) exposed to elevated seawater temperature, salinity and ultraviolet light was tested against the microarray to determine patterns of gene expression associated with each stressor. Carbonic anhydrase, thioredoxin, a urokinase plasminogen activator receptor (uPAR) and three ribosomal genes demonstrated differential expression across all replicates on the array and between replicate colonies. Specific gene expression patterns produced in response to different stressors demonstrate the potential for gene expression profiling in characterizing the coral stress response.     

Community forests and regeneration in post-industrial landscapes

Through a critique of existing regeneration literatures the paper points to the close relationship between regeneration and sustainable development. It suggests that the economic aspects of sustainable development have tended to dominate: leading to the neglect of nature in both regeneration and sustainable development, with regeneration having a principal focus on socio-economic issues in urban settings. To address these lacunae we suggest the need for a more environmentally sensitive regeneration theory. Using this approach the paper draws on recent in-depth research in three post-industrial coalfield areas where regeneration processes operate in the form of community forest projects. It provides a critical perspective on these regeneration processes, integrating theory with empirical data and highlighting how nature is drawn into broader economic and social processes of regeneration. In conclusion, using forestry initiatives as examples, we reflect on the conceptual dissonance apparent in regeneration theory and practice, and point to theoretical insights that could enable a more critical regeneration theory; more beneficial outcomes to regeneration processes; and an improved understanding of the relations between nature, capital and community in regeneration processes and sustainable development.     

The 2dF Galaxy Redshift Survey: the power spectrum and the matter content of the Universe

The 2dF Galaxy Redshift Survey has now measured in excess of 160 000 galaxy redshifts. This paper presents the power spectrum of the galaxy distribution, calculated using a direct Fourier transform based technique. We argue that, within the k -space region     , the shape of this spectrum should be close to that of the linear density perturbations convolved with the window function of the survey. This window function and its convolving effect on the power spectrum estimate are analysed in detail. By convolving model spectra, we are able to fit the power-spectrum data and provide a measure of the matter content of the Universe. Our results show that models containing baryon oscillations are mildly preferred over featureless power spectra. Analysis of the data yields 68 per cent confidence limits on the total matter density times the Hubble parameter     , and the baryon fraction     , assuming scale-invariant primordial fluctuations.     

Real-Time River Level Monitoring Using GPS Heighting

This paper presents the current progress of the River Level Monitoring using GPS Heighting (RiGHt) project. The aim of the project is to develop an integrated system to allow the continuous monitoring of river heights using a buoy equipped with Global Positioning System (GPS) and satellite communications and using Geographical Information System (GIS) techniques. ? 2000 John Wiley & Sons, Inc.     

Thinking globally and siting locally – renewable energy and biodiversity in a rapidly warming world

Increasing greenhouse gas emissions are projected to raise global average surface temperatures by 3?–4 °C within this century, dramatically increasing the extinction risk for terrestrial and freshwater species and severely disrupting ecosystems across the globe. Limiting the magnitude of warming and its devastating impacts on biodiversity will require deep emissions reductions that include the rapid, large-scale deployment of low-carbon renewable energy. Concerns about potential adverse impacts to species and ecosystems from the expansion of renewable energy development will play an important role in determining the pace and scale of emissions reductions and hence, the impact of climate change on global biodiversity. Efforts are underway to reduce uncertainty regarding wildlife impacts from renewable energy development, but such uncertainty cannot be eliminated. We argue the need to accept some and perhaps substantial risk of impacts to wildlife from renewable energy development in order to limit the far greater risks to biodiversity loss owing to climate change. We propose a path forward for better reconciling expedited renewable energy development with wildlife conservation in a warming world.     

Geographic limits to global labor market flexibility: The human resources paradox of the cruise industry

The cruise industry enjoys arguably the most flexible and globalized of all labor markets. Yet, in an apparent paradox, cruise lines face a potential labor shortage, despite the fact that the bulk of their labor is sourced from the Global South where a large labor surplus would seemingly make recruitment a simple process. This paper examines this paradox in greater detail with a focus on the tension that exists between the industry’s demand for a flexible labor force, and the need for workers who maintain the skills required of a cruise ship job. It is argued that the contemporary geography of global labor recruitment is constrained by the particular political, economic and cultural circumstances of individual source countries that make certain cohorts less attractive or available as a workforce. In practice the need for skill and flexibility are not always reconcilable and cruise lines have found that there is a geographic limit to labor market flexibility. The article is based on interviews with various stakeholders involved in either working on cruise ships or in recruiting workers. Special emphasis is placed on Filipino cruise ship workers and labor recruiters as a means to discuss labor recruitment for the entire industry.     

“Stones from the dangerous winds”: reef platform mega-clasts in the tropical Pacific Islands

Tsunamis and intense tropical storms compete as viable mechanisms for catastrophic marine inundations of coastlines, and so interpretation of deposits laid down by palaeo-events is often problematic. Here, examples are presented from the tropical South Pacific Islands to demonstrate how indigenous knowledge may provide vital clues supporting sedimentological investigation and thereby helping to explain the origin of giant boulders emplaced on top of coral reef platforms.     

Characterization of bacterial symbioses in Myrtea sp. (Bivalvia: Lucinidae) and Thyasira sp. (Bivalvia: Thyasiridae) from a cold seep in the Eastern Mediterranean

Cold seeps have recently been discovered in the Nile deep‐sea fan (Eastern Mediterranean), and data regarding associated fauna are still scarce. In this study, two bivalve species associated with carbonate crusts and reduced sediment are identified based on sequence analysis of their 18S and 28S rRNA‐encoding genes, and associated bacterial symbioses are investigated using 16S rRNA gene sequencing and microscopy‐based approaches. The specimens are closely related to Myrtea spinifera and Thyasira flexuosa, two species previously documented at various depths from other regions but not yet reported from the Eastern Mediterranean. Both species harbour abundant gammaproteobacterial endosymbionts in specialized gill epithelial cells. The Myrtea‐associated bacterium is closely related to lucinid symbionts from both deep‐sea and coastal species, whereas the Thyasira‐associated bacterium is closely related to the symbiont of a T. flexuosa from coastal waters off the U.K. An epsilonproteobacterial sequence has also been identified in Thyasira which could correspond to a helicoid‐shaped morphotype observed by electron microscopy, but this was not confirmed using fluorescent in situ hybridization. Virus‐like particles were observed within some symbionts in Thyasira, mostly in bacteriocytes localized close to the ciliated zone of the gill filament. Overall, results indicate that very close relatives of shallow species M. spinifera and T. flexuosa occur at cold seeps in the Eastern Mediterranean and harbour chemoautotrophic symbioses similar to those found in their coastal relatives.