Annotated record of the detailed examination of Mn deposits from R/V Atlantis Cruise 160 stations

The cores described were taken by the personnel of the Lamont-Doherty Earth Observatory (LDEO) operating as guests scientists during the R/V Atlantis Cruise 160 undertaken by the Woods Hole Oceanographic Institution from Januray until April 1950. A total of 23 cores were recovered and are available at Lamont-Doherty Earth Observatory for sampling and study.

(Appendix) Carbon and nitrogen isotope ratios of ODP Site 160-964

Nitrogen isotopes of chlorins, degradation products of chlorophyll, reflect the isotopic composition of nutrient N utilized by marine phytoplankton communities. Here we show that in sediments of the eastern Mediterranean Pleistocene and Holocene, values of d15N for chlorins and total nitrogen vary in concert, with a consistent offset of ~5 per mil reflecting the fractionation imparted during chlorophyll biosynthesis. Samples from the Integrated Ocean Drilling Program Sites 964 and 969 were analyzed at a sampling resolution of ~4-10 cm, clustered around sapropel events 2, 3, 4 and 5 (~100-170 ka). In low organic content sediments, chlorin values of ~0 per mil coincident with total nitrogen values of ~+ 5 per mil indicate that the latter reflects the original biomass and is not a consequence of diagenetic isotope enrichment. In sapropel horizons, the chlorin and total nitrogen values are 5 per mil more negative (~-5 per mil and ~ 0 per mil, respectively), resembling previously-reported, modern-day water-column particulates (~0 per mil). We suggest that nutrient conditions in the Eastern Mediterranean correspond to three scenarios and that the similarity between sapropel and modern-day bulk d15N is coincidental. Organic-poor marl sediments formed under oligotrophic conditions where surface productivity resulted from upwelling of Atlantic-sourced nitrate. Sapropels were characterized by enhanced diazotrophy that was likely fueled by increased riverine P fluxes to surface waters. Present-day conditions are dominated by anthropogenic N sources. These scenarios agree with a model of sapropel formation in which stratification caused by increased fresh-water inputs led to N fixation due to P:N nutrient imbalance. Enhanced production combined with stratification promoted and maintained anoxic deep waters, consequently increasing organic matter preservation. Such a model may be relevant to interpreting other episodes of intense organic matter deposition in past oceans.

Modernist 16-19 Business Education in a Postmodern world - critical evidence of business practice and business education in the cultural industries

This article examines the continued relevance of the 16-19 business education curriculum in the UK, stimulated by doubts expressed by Thomas (1996), over its continued relevance. We express a concern that business education needs, but is struggling, to respond to significant societal shifts in consumption and production strategies that do not sit easily within traditional theories of business practice currently underpinning 16-19 business education. We examine firstly, the extent to which a formal body of knowledge couched in a modernist discourse of facts and objectivity can cope with the changing and fluid developments in much current business practice that is rooted in the cultural and symbolic. Secondly, the extent to which both academic and vocational competences provide the means for students to develop a framework of critical understanding that can respond effectively to rapidly changing business environments.Findings are based on research conducted jointly by the University of Manchester and the Manchester Institute for Popular Culture at Manchester Metropolitan University. The growth of dynamism of the cultural industries sector - largely micro-businesses and small and medium sized enterprises (SMEs) -encapsulates forms of business knowledge, business language and business practice which may not immediately fit with the models provided within business education. Results suggest increasingly reflexive forms of consumption being met by similarly reflexive and flexible modes of production.Our evidence suggests that whilst modernist business knowledge is often the foundation for many 16-19 business education courses, these programmes of study/training do not usually reflect the activities of SME and micro-business practitioners in the cultural industries. Given the importance of cultural industries in terms of the production strategies required to meet increasingly reflexive markets, it is suggested that there may be a need to incorporate a postmodern approach to the current content and pedagogy; one that is contextual, cultural and discursive.

Spontaneous pacing during overground hill running

Purpose: To investigate speed regulation during overground running on undulating terrain. Methods: Following an initial laboratory session to calculate physiological thresholds, eight experienced runners completed a spontaneously paced time trial over 3 laps of an outdoor course involving uphill, downhill and level sections. A portable gas analyser, GPS receiver and activity monitor were used to collect physiological, speed and stride frequency data. Results: Participants ran 23% slower on uphills and 13.8% faster on downhills compared with level sections. Speeds on level sections were significantly different for 78.4 ± 7.0 seconds following an uphill and 23.6 ± 2.2 seconds following a downhill. Speed changes were primarily regulated by stride length which was 20.5% shorter uphill and 16.2% longer downhill, while stride frequency was relatively stable. Oxygen consumption averaged 100.4% of runner’s individual ventilatory thresholds on uphills, 78.9% on downhills and 89.3% on level sections. 89% of group level speed was predicted using a modified gradient factor. Individuals adopted distinct pacing strategies, both across laps and as a function of gradient. Conclusions: Speed was best predicted using a weighted factor to account for prior and current gradients. Oxygen consumption (VO2) limited runner’s speeds only on uphill sections, and was maintained in line with individual ventilatory thresholds. Running speed showed larger individual variation on downhill sections, while speed on the level was systematically influenced by the preceding gradient. Runners who varied their pace more as a function of gradient showed a more consistent level of oxygen consumption. These results suggest that optimising time on the level sections after hills offers the greatest potential to minimise overall time when running over undulating terrain.

Thermal analysis of synthetic reevesite and cobalt substituted reevesite (Ni,Co)6Fe2(OH)16(CO3)•4H2O

The mineral reevesite and the cobalt substituted reevesite have been synthesised. The d(003) spacings of the minerals ranged from 7.54 to 7.95 Å. The maximum d(003) value occurred at around Ni:Co 0.4:0.6. This maximum in interlayer distance is proposed to be due to a greater number of carbonate anions and water molecules intercalated into the structure. The stability of the reevesite and cobalt doped reevesite was determined by thermogravimetric analysis. The maximum temperature of the reevesite occurs for the unsubstituted reevesite and is around 220°C. The effect of cobalt substitution results in a decrease in thermal stability of the reevesites. Four thermal decomposition steps are observed and are attributed to dehydration, dehydroxylation and decarbonation, decomposition of the formed carbonate and oxygen loss at ~807 °C. A mechanism for the thermal decomposition of the reevesite and the cobalt substituted reevesite is proposed.

Alkaline hydrothermal treatment of titanate nanostructures

Since its initial proposal in 1998, alkaline hydrothermal processing has rapidly become an established technology for the production of titanate nanostructures. This simple, highly reproducible process has gained a strong research following since its conception. However, complete understanding and elucidation of nanostructure phase and formation have not yet been achieved. Without fully understanding phase, formation, and other important competing effects of the synthesis parameters on the final structure, the maximum potential of these nanostructures cannot be obtained. Therefore this study examined the influence of synthesis parameters on the formation of titanate nanostructures produced by alkaline hydrothermal treatment. The parameters included alkaline concentration, hydrothermal temperature, the precursor material‘s crystallite size and also the phase of the titanium dioxide precursor (TiO2, or titania). The nanostructure‘s phase and morphology was analysed using X-ray diffraction (XRD), Raman spectroscopy and transmission electron microscopy. X-ray photoelectron spectroscopy (XPS), dynamic light scattering (non-invasive backscattering), nitrogen sorption, and Rietveld analysis were used to determine phase, for particle sizing, surface area determinations, and establishing phase concentrations, respectively. This project rigorously examined the effect of alkaline concentration and hydrothermal temperature on three commercially sourced and two self-prepared TiO2 powders. These precursors consisted of both pure- or mixed-phase anatase and rutile polymorphs, and were selected to cover a range of phase concentrations and crystallite sizes. Typically, these precursors were treated with 5–10 M sodium hydroxide (NaOH) solutions at temperatures between 100–220 °C. Both nanotube and nanoribbon morphologies could be produced depending on the combination of these hydrothermal conditions. Both titania and titanate phases are comprised of TiO6 units which are assembled in different combinations. The arrangement of these atoms affects the binding energy between the Ti–O bonds. Raman spectroscopy and XPS were therefore employed in a preliminary study of phase determination for these materials. The change in binding energy from a titania to a titanate binding energy was investigated in this study, and the transformation of titania precursor into nanotubes and titanate nanoribbons was directly observed by these methods. Evaluation of the Raman and XPS results indicated a strengthening in the binding energies of both the Ti (2p3/2) and O (1s) bands which correlated to an increase in strength and decrease in resolution of the characteristic nanotube doublet observed between 320 and 220 cm.1 in the Raman spectra of these products. The effect of phase and crystallite size on nanotube formation was examined over a series of temperatures (100.200 �‹C in 20 �‹C increments) at a set alkaline concentration (7.5 M NaOH). These parameters were investigated by employing both pure- and mixed- phase precursors of anatase and rutile. This study indicated that both the crystallite size and phase affect nanotube formation, with rutile requiring a greater driving force (essentially �\harsher. hydrothermal conditions) than anatase to form nanotubes, where larger crystallites forms of the precursor also appeared to impede nanotube formation slightly. These parameters were further examined in later studies. The influence of alkaline concentration and hydrothermal temperature were systematically examined for the transformation of Degussa P25 into nanotubes and nanoribbons, and exact conditions for nanostructure synthesis were determined. Correlation of these data sets resulted in the construction of a morphological phase diagram, which is an effective reference for nanostructure formation. This morphological phase diagram effectively provides a .recipe book�e for the formation of titanate nanostructures. Morphological phase diagrams were also constructed for larger, near phase-pure anatase and rutile precursors, to further investigate the influence of hydrothermal reaction parameters on the formation of titanate nanotubes and nanoribbons. The effects of alkaline concentration, hydrothermal temperature, crystallite phase and size are observed when the three morphological phase diagrams are compared. Through the analysis of these results it was determined that alkaline concentration and hydrothermal temperature affect nanotube and nanoribbon formation independently through a complex relationship, where nanotubes are primarily affected by temperature, whilst nanoribbons are strongly influenced by alkaline concentration. Crystallite size and phase also affected the nanostructure formation. Smaller precursor crystallites formed nanostructures at reduced hydrothermal temperature, and rutile displayed a slower rate of precursor consumption compared to anatase, with incomplete conversion observed for most hydrothermal conditions. The incomplete conversion of rutile into nanotubes was examined in detail in the final study. This study selectively examined the kinetics of precursor dissolution in order to understand why rutile incompletely converted. This was achieved by selecting a single hydrothermal condition (9 M NaOH, 160 °C) where nanotubes are known to form from both anatase and rutile, where the synthesis was quenched after 2, 4, 8, 16 and 32 hours. The influence of precursor phase on nanostructure formation was explicitly determined to be due to different dissolution kinetics; where anatase exhibited zero-order dissolution and rutile second-order. This difference in kinetic order cannot be simply explained by the variation in crystallite size, as the inherent surface areas of the two precursors were determined to have first-order relationships with time. Therefore, the crystallite size (and inherent surface area) does not affect the overall kinetic order of dissolution; rather, it determines the rate of reaction. Finally, nanostructure formation was found to be controlled by the availability of dissolved titanium (Ti4+) species in solution, which is mediated by the dissolution kinetics of the precursor.

The synthesis and spectroscopic characterisation of hydrotalcite formed from aluminate solutions

Raman spectroscopy has been used to characterise nine hydrotalcites prepared from aluminate and magnesium solutions (magnesium chloride and seawater). The aluminate hydrotalcites are proposed to have the following formula Mg6Al2(OH)16(CO32-).xH2O, Mg6Al2(OH)16(CO32-,SO42-).xH2O, and Mg6Al2(OH)16(SO42-).xH2O. The synthesis of these hydrotalcites using seawater results in the intercalation of sulfate anions into the hydrotalcite interlayer. The spectra have been used to assess the molecular assembly of the cations and anions in the hydrotalcite structures. The spectra have been conveniently subdivided into spectral features based upon the carbonate anion, the hydroxyl units and water units. This investigation has shown the ideal conditions to form hydrotalcite from aluminate solutions is at pH 14 using magnesium chloride. Changes in synthesis conditions resulted in the formation of impurity products aragonite, thenardite, and gypsum.