Development and deployment of a precision underwater positioning system for in situ laser Raman spectroscopy in the deep ocean

The field of ocean geochemistry has recently been expanded to include in situ laser Raman spectroscopic measurements in the deep ocean. While this technique has proved to be successful for transparent targets, such as fluids and gases, difficulty exists in using deep submergence vehicle manipulators to position and control the very small laser spot with respect to opaque samples of interest, such as many rocks, minerals, bacterial mats, and seafloor gas hydrates. We have developed, tested, and successfully deployed by remotely operated vehicle (ROV) a precision underwater positioner (PUP) which provides the stability and precision movement required to perform spectroscopic measurements using the Deep Ocean Raman In situ Spectrometer (DORISS) instrument on opaque targets in the deep ocean for geochemical research. The positioner is also adaptable to other sensors, such as electrodes, which require precise control and positioning on the seafloor. PUP is capable of translating the DORISS optical head with a precision of 0.1 mm in three dimensions over a range of at least 15 cm, at depths up to 4000 m, and under the normal range of oceanic conditions (T, P, current velocity). The positioner is controlled, and spectra are obtained, in real time via Ethernet by scientists aboard the surface vessel. This capability has allowed us to acquire high quality Raman spectra of targets such as rocks, shells, and gas hydrates on the seafloor, including the ability to scan the laser spot across a rock surface in sub-millimeter increments to identify the constituent mineral grains. These developments have greatly enhanced the ability to obtain in situ Raman spectra on the seafloor from an enormous range of specimens.     

Integrated mapping of groundwater drought risk in the Southern African Development Community (SADC) region

Groundwater drought denotes the condition and hazard during a prolonged meteorological drought when groundwater resources decline and become unavailable or inaccessible for human use. Groundwater drought risk refers to the combined physical risk and human vulnerability associated with diminished groundwater availability and access during drought. An integrated management support tool, GRiMMS, is presented, for the mapping and assessment of relative groundwater drought risk in the Southern African Development Community (SADC) region. Based on composite mapping analysis of region-wide gridded relative indices of meteorological drought risk, hydrogeological drought proneness and human groundwater drought vulnerability, the mapping results highlight consistent areas across the region with highest groundwater drought risk and populations in the order of 39 million at risk of groundwater drought at present. Projective climate-model results suggest a potentially significant negative impact of climate change on groundwater drought risk. The tool provides a means for further attention to the key, but neglected, role of groundwater in drought management in Africa.     

Solute geochemical mass-balances and mineral weathering rates in small watersheds II: Biomass nutrient uptake,more equations in more unknowns,and land use/land cover effects

Paired watersheds are used to develop a deciduous nutrient uptake stoichiometry. The watersheds are those of the House Rock Run and the Brubaker Run located in the Pennsylvania Appalachian Piedmont, USA. These two watersheds are nearly identical with respect to bedrock, regolith, climate, geomorphology, morphometry, baseflow hydrology, and type and successional stage of forest vegetation. They only differ by the percentage of deciduous forest cover, with House Rock Run having 59% and Brubaker Run having 76%. From differences in their stream chemistries the biomass nutrient uptake stoichiometry of K_1.0Mg_1.0Ca_1.4 was determined. This stoichiometry applies to an aggrading deciduous biomass and differs from those previously used which were derived from net primary production (NPP) data. The difference may reflect that macronutrients in plant tissue may also originate from atmospheric inputs and/or decomposing biomass. Although this stoichiometry may not be applied to all deciduous forest-covered watersheds, it is likely an improvement over a stoichiometry determined from NPP data.     

NEW METHOD FOR IDENTIFICATION OF ANCIENT STARCH WITH THERMOSTABLE ALPHA-AMYLASE

目前古代淀粉粒鉴别的两种方法,即显微镜观察法和碘着色测试法,均不能确保鉴别的准确性.针对耐热性α-淀粉酶只对淀粉产生降解的特点,设计出古代淀粉粒鉴别的“耐热性α-淀粉酶降解法”,并运用到考古样品中淀粉粒的分析和鉴定之中.本文详细介绍了耐热性α-淀粉酶降解法的原理和流程,并通过古代淀粉粒的鉴别实验,确定了该方法在确切鉴别考古样品中淀粉粒的实用性和有效性;同时现代大麦和莲藕淀粉粒的降解实验结果表明不同植物来源以及同种植物内部不同粒径的淀粉粒其降解速率存在明显差异,而古代淀粉粒在耐热性α-淀粉酶作用下出现的降解速率差异的现象,或可揭示古代淀粉粒的植物来源,甚至长期埋藏对其产生的影响.     

Employability and flexible retirement: Variations in academia in an age of austerity

With both declining and ageing populations, countries are addressing the threats to their competitiveness by attracting more highly educated workers and by investing in human capital, especially through policies to increase the rates of participation by young people in tertiary education. As the population is still ageing, there are concerns over the affordability of state support for the elderly, their roles in society and the economy. Active and flexible lifestyles extend healthy life expectancy, so extending the length of the working life is increasingly seen as a way to ease the transition to an economy where an ageing population is affordable.Senior academic staff, exemplars of such post-industrial flexibility, have long been accommodated beyond the statutory retirement age. Their benign conditions of work; high private and social returns to experience and knowledge; and their high levels of those skills, labour power and other capacities which do not degenerate with age, combine to prolong the length of their effective working lives. Against this, as in other sectors, redundancies, voluntary severance and other schemes to reduce staffing have encouraged early retirement. Increased demand for higher education has driven changes in the lecturing labour mix, with increasing use of a peripheral workforce of both early career and retiring staff. This has seen semi-retirement within higher education evolving to stretch the period over which withdrawal takes place.In this context, the exploratory work reported here considers the initial responses by employers and trades unions in Scottish Higher Education to the abolition of the default retirement age and the introduction of ‘The Employment Equality (Repeal of Retirement Age Provisions) Regulations 2011’.     

Measuring bluff erosion part 2: pairing aerial photographs and terrestrial laser scanning to create a watershed scale sediment budget

Effectively managing and reducing high suspended sediment loads in rivers requires an understanding of the magnitude of major sediment sources as well as erosion and transport processes that deliver excess fine sediments to the channel network. The focus of this research is to determine the magnitude of erosion from tall bluffs, a primary sediment source in the 2880 km² Le Sueur watershed, Minnesota, USA. We coupled analyses of seven decades of aerial photographs with four years of repeat terrestrial laser scanning (TLS) to determine erosion rates on bluffs. Together, these datasets provide decadal‐scale retreat rates throughout the entire watershed and high‐resolution geomorphic change detection on a subset of bluffs to both constrain erosion rates and document how environmental conditions affect bluff retreat. Erosion rates from aerial photographs and TLS were extrapolated from 243 and 15 measured bluffs, respectively, to all 480 bluffs in the Le Sueur watershed using multiple techniques to obtain estimates of sediment loading from these features at the watershed‐scale. Despite different spatial and temporal measurement scales, the aerial photograph and TLS estimates yielded similar results for bluff retreat rate and total mass of sediment derived from bluffs, with bluffs in the Le Sueur watershed yielding 135 000 ± 39 000 Mg/yr of fine sediment. Comparing this value to the average annual total suspended solids (TSS) load determined from gauging from 2000 to 2010, we determined that bluffs comprise 57 ± 16% of the total TSS load, making bluffs the single most abundant fine sediment source in the basin. Copyright © 2012 John Wiley & Sons, Ltd.     

Kos Plateau Tuff (KPT) on Kalymnos island, Aegean volcanic arc: A geochemical approach

Thirteen pumice samples from the D and E ignimbrite units of Kalymnos Tuff have been analyzed for their biotite and feldspar phenocryst mineral chemistry and for bulk major and 20 trace, including 14 Rare Earth elements, to define and compare their petrochemistry with the Kos Plateau Tuff (KPT). For the same purpose major element analyses were obtained from Kalymnos Tuff and KPT glasses. Both KPT and Kalymnos pumice lapilli are rhyolites characterized by a well-developed ‘silky’ texture and roundish quartz. Phenocrysts of biotite and feldspars (sanidine, oligoclase) from both tuffs display compositional overlap. Crystals are charac-terized by undulatory extinction (quartz), fractures (sanidine, oligoclase) and bent cleavages (biotite) due to the explosive origin of their host. Both tuffs show well-defined petrogenetic trends and extensive compositional overlaps on major and trace element variation diagrams suggesting that they are consanguineous. However, D ignimbrite samples are more evolved than those obtained from E ignimbrite as indicated from major elements, alkali earths (Ba, Rb, Sr), immobile (Zr, Y), compatible (V) and hygromagmatophile trace element (Th) distributions. This evidence indicates a stratified magma chamber under a ～16 Km caldera superstructure which is mostly submarine.     

Katrina and Migration: Evacuation and Return by African Americans and Vietnamese Americans in an Eastern New Orleans Suburb

Hurricane Katrina constitutes the most costly natural as well as technology-induced disaster, in terms of both human suffering and financial loss in the history of the United States. Even years later, it continues to profoundly impact the livelihoods and the mental and physical health of those who have experienced evacuation and return and those who have begun lives anew elsewhere. Our study focuses on these geographical processes associated with the Katrina disaster experiences of African Americans and Vietnamese Americans comprising an overwhelming majority (93.4 percent) of residents in a racially mixed pre-Katrina eastern New Orleans neighborhood. We examine the spatial morphology of routes, volumes, and frequencies of evacuees; their return rates and experiences; and rationales and motivations to return or stay. The conceptual framework is based on the disaster migration, place attachment, and social network literature. Both quantitative and qualitative evidence indicates that the evacuation and return experiences of each minority group substantially differed, especially among African American women, and this was strongly influenced by existing social networks.     

Women in geography in the 21st century. Introductory Remarks: Structure,Agency, and Women Geographers in Academia at the End of the Long Twentieth Century

This paper provides an introduction to the set of articles presented in the focus section Women in Geography in the 21st Century. The paper argues that feminist geographers should view their professional biographies in a structure-agency context. Such a theoretical perspective views events that are commonly thought to be unique and attributable to individual merit or foible as the outcome instead of interactions between actors and social structures. Creating genuinely equal opportunities in geography departments for women and others who are different from the able-bodied, middle-class, white heterosexual male model of “the geographer” depends upon challenges to and transformations of the structures which bear on the discipline, rather than solely upon individual initiative.     

Bio-gentrification: vulnerability bio-value chains in gentrifying neighbourhoods†

In this paper, I develop the concept of “bio-gentrification” as a way to broaden critical theoretical debates on the relationship between gentrification and “social mixing” policies. Bio-gentrification weds urban Marxist political economic insights to the neo-Foucauldian notion of biopower. The former stresses spatial tactics of removal and displacement and value generated through land and property. The latter assesses a wider terrain of spatial tactics, their relationship to knowledge produced about humans as living beings, and their alignment with capitalist urbanization. The Vancouver example illuminates how social mixing “truths” and practices to which they are tied generate value by naturalizing human insecurity in situ and transforming the biological existence of disadvantaged peoples into raw material for profit through a process that can be conceptualized as a “vulnerability bio-value chain.” Bio-gentrification refers to the tension between removal and embedding of disadvantaged peoples and points to the need for a bio-gentrification politics to confront this dynamic.