bluuebunny/crossref_metadata_2025 huggingface dataset:
The Initial Response of a Chenopod Shrubland Plant and Invertebrate Community to Two Pulses of Intensive Cattle Grazing.
Authors: Read JL
Published: December 2005

The initial effect of two pulses of heavy cattle grazing on chenopod shrubland plants and invertebrates in northern South Australia was assessed in a two year trial. Both plant and invertebrate communities were structured by subhabitats which were defined by edaphic and water-distribution features. The cover of grasses and the dominant shrubs, Atriplex vesicaria and Maireana astrotricha, declined significantly following grazing but only total vegetation cover was significantly lower than controls one year after grazing. Plant species richness was not affected by the grazing pulses. Abundance of ants increased, but the responses of other invertebrates were inconsistent following grazing. Rainfall had a marked effect upon both plant cover and invertebrate abundance. Key words: chenopod shrublands, pulsed cattle grazing, Atriplex vesicaria, invertebrates, bioindicators
The Effects of Perennial Grasses, Stocking Rate and Rainfall on Sheep Production in a Semi-Arid Woodland of Eastern Australia.
Authors: Freudenberger D , Wilson A , Palmer R
Published: December 2005

A grazing study was conducted in a semi-arid mulga (Acacia aneura) woodland to determine the relative
importance of variables controlling sheep production in this environment. The study was based on six
sheep stocking rates (0.3-0.8 sheeplha) with the exclusion of other large herbivores including kangaroos
and feral goats. The availability of forage and its components, together with the wool growth and live
weight of the sheep were measured every three months for seven years from October 1986.
Annual rainfall accounted for 60% of the annual variation in live weight gain per head and 79% of the
variation in wool growth per head. Stocking rate accounted for an additional 10% of the variation.
Rainfall accounted for this large proportion of variation by its strong influence on the yield of green leaf
which accounted for 78% of the variation in live weight gain and 66% of the variation in wool growth.
Green leaf was a determinant of sheep production because of its superior crude protein content and
digestibility compared to dry leaf and stem.
The species comprising this green leaf had an influence on sheep production only during drier years
when the presence of palatable perennial grasses became important to sheep production. The frequency
and yield of perennial grasses were greatly diminished at high stocking rates. This change in forage
composition caused a decline in sheep productivity as detected by a loss of linearity in the relationship
between stocking rate and live weight gainlhead.
We conclude that adjusting stocking rates is required in this environment for maintenance of long-term
sheep productivity and landscape function. The loss of palatable perennial C, grasses over much of the
region has reduced livestock productivity and increased the variability in forage availability. Stock
numbers should be adjusted at critical times to avoid losing perennial grasses that are important for sheep
production in drier years. New grazing strategies are required to restore these grasses to the region.
Gs and Gi coupling of adrenomedullin in adult rat ventricular myocytes
Authors: Mittra Shivani , Bourreau Jean-Pierre
Published: December 2005

Adrenomedullin (ADM) acts as an autocrine or a paracrine factor in the regulation of cardiac function. The intracellular mechanisms involved in the direct effect of ADM on adult rat ventricular myocytes (ARVMs) are still to be elucidated. In ARVMs from normal rats, ADM produced an initial (<30 min) increase in cell shortening and Ca2+ transients and a marked decrease in both on prolonged incubation (>1 h). Both effects were sensitive to ADM antagonist ADM-(22–52). Treatment with SQ-22536, an inhibitor of adenylate cyclase, blocked the positive inotropic effect of ADM and potentiated its negative inotropic effect. The negative inotropic effect was sensitive to inhibition by pertussis toxin (PTX), an inhibitor of Gi proteins and KT-5720, an inhibitor of PKA. The observations suggest a switch from Gs-coupled to PTX-sensitive, PKA-dependent Gi coupling by ADM in ARVMs. The ADM-mediated Gi-signaling system involves cAMP-dependent pathways because SQ-22536 further increased the negative inotropic actions of ADM. Also, because ADM is overproduced by ARVMs in our rat model of septic shock, ARVMs from LPS-treated rats were subjected to treatment with ADM-(22–52) and PTX. The decrease in cell shortening and Ca2+ transients in LPS-treated ARVMs could be reversed back with ADM-(22–52) and PTX. This indicates that ADM plays a role in mediating the negative inotropic effect in LPS-treated ARVM through the activation of Gi signaling. This study delineates the intracellular pathways involved in ADM-mediated direct inotropic effects on ARVMs and also suggests a role of ADM in sepsis.
Calcium spark properties in ventricular myocytes are altered in aged mice
Authors: Howlett Susan E. , Grandy Scott A. , Ferrier Gregory R.
Published: December 2005

This study determined whether whole cell Ca2+ transients and unitary sarcoplasmic reticulum (SR) Ca2+ release events are constant throughout adult life or whether Ca2+ release is altered in aging ventricular myocytes. Myocytes were isolated from young adult (∼5 mo old) and aged (∼24 mo old) mice. Spontaneous Ca2+ sparks and Ca2+ transients initiated by field stimulation were detected with fluo-4. All experiments were conducted at 37°C. Ca2+ transient amplitudes were reduced, and Ca2+ transient rise times were abbreviated in aged cells stimulated at 8 Hz compared with young adult myocytes. Furthermore, the incidence and frequency of spontaneous Ca2+ sparks were markedly higher in aged myocytes compared with young adult cells. Spark amplitudes and spatial widths were similar in young adult and aged myocytes. However, spark half-rise times and half-decay times were abbreviated in aged cells compared with younger cells. Resting cytosolic Ca2+ levels and SR Ca2+ stores were assessed by rapid application of caffeine in fura-2-loaded cells. Neither resting Ca2+ levels nor SR Ca2+ content differed between young adult and aged cells. Thus increased spark frequency in aging cells was not attributable to increased SR Ca2+ stores. Furthermore, the decrease in Ca2+ transient amplitude was not due to a decrease in SR Ca2+ load. These results demonstrate that alterations in fundamental SR Ca2+ release units occur in aging ventricular myocytes and raise the possibility that alterations in Ca2+ release may reflect age-related changes in fundamental release events rather than changes in SR Ca2+ stores and diastolic Ca2+ levels.
Sodium azide dilates coronary arterioles via activation of inward rectifier K+channels and Na+-K+-ATPase
Authors: Qamirani Erion , Razavi Habib M. , Wu Xin , Davis Michael J. , Kuo Lih , Hein Travis W.
Published: December 2005

Sodium azide (NaN3), a potent vasodilator, causes severe hypotension on accidental exposure. Although NaN3has been shown to increase coronary blood flow, the direct effect of NaN3on coronary resistance vessels and the mechanism of the NaN3-induced response remain to be established. To address these issues without confounding influences from systemic parameters, subepicardial coronary arterioles were isolated from porcine hearts for in vitro study. Arterioles developed basal tone at 60 cmH2O intraluminal pressure and dilated acutely, in a concentration-dependent manner, to NaN3(0.1 μM to 50 μM). The NaN3response was not altered by the nitric oxide synthase inhibitor NG-nitro-l-arginine methyl ester or endothelial removal. Neither inhibition of phosphoinositol 3-kinase and tyrosine kinases nor blockade of ATP-sensitive, Ca2+-activated, and voltage-dependent K+channels affected NaN3-induced dilation. However, the vasomotor action of NaN3was significantly attenuated in a similar manner by the inward rectifier K+(KIR) channel inhibitor Ba2+, the Na+-K+ATPase inhibitor ouabain, or the guanylyl cyclase inhibitor 1 H-[1,2,4]oxadiazolo[4,3,- a]quinoxalin-1-one (ODQ). Ba2+, in combination with either ouabain or ODQ, nearly abolished the vasodilatory response. However, there was no additive inhibition by combining ouabain and ODQ. The NaN3-mediated vasodilation was also attenuated by morin, an inhibitor of phosphatidylinositolphosphate (PIP) kinase, which can regulate KIRchannel activity. With the use of whole cell patch-clamp methods, NaN3acutely enhanced Ba2+-sensitive KIRcurrent in isolated coronary arteriolar smooth muscle cells. Collectively, this study demonstrates that NaN3, at clinically toxic concentrations, dilates coronary resistance vessels via activation of both KIRchannels and guanylyl cyclase/Na+-K+-ATPase in the vascular smooth muscle. The KIRchannels appear to be modulated by PIP kinase.
Modulation of contractility by myocyte-derived arginase in normal and hypertrophied feline myocardium
Authors: Jung Albert S. , Kubo Hajime , Wilson Rachel , Houser Steven R. , Margulies Kenneth B.
Published: December 2005

l-Arginine, the sole substrate for the nitric oxide (NO) synthase (NOS) enzyme in producing NO, is also a substrate for arginase. We examined normal feline hearts and hearts with compensated left ventricular (LV) hypertrophy (LVH) produced by ascending aorta banding. Using Western blot analysis, we examined the abundance of arginase isozymes in crude homogenates and isolated cardiac myocytes obtained from the LVs of normal and LVH hearts. We examined the functional significance of myocyte arginase via measurement of shortening and intracellular calcium in isolated myocytes in the presence and absence of boronoethyl chloride (BEC), a specific pharmacological inhibitor of arginase. Both arginase I and II were detected in crude myocardial homogenates, but only arginase I was present in isolated cardiac myocytes. Arginase I was downregulated in LVH compared with normal. Inhibition of arginase with BEC reduced fractional shortening, maximal rate of shortening (+d L/d t) and relengthening (−d L/d t), and the peak of the free cytosolic calcium transient in normal myocytes but did not affect these parameters in LVH myocytes. These negative inotropic actions of arginase inhibition were associated with increases in cGMP generation. These studies indicate that only arginase I is present in cardiac myocytes where it tends to limit NO and cGMP production with the effect of supporting basal contractility. In experimental LVH induced by pressure overload, our studies demonstrate reduced arginase I expression and reduced functional significance, allowing greater arginine substrate availability for NO/cGMP signaling.
Tradition and Modernism between Continuity and Discontinuity: Possible Models and Historical Options
Authors: Hanafi Hassan
Published: December 2005

This article discusses three models of continuity and discontinuity as the subjects of an intercultural philosophy based on the historical experiences of peoples and cultures, instead of on hypothetical and purely theoretical reflections. There are three main models, each of them dominating a specific cultural area: the Western model of discontinuity between tradition and modernity, the Eastern model of juxtaposing the old and the new, and the Islamic model of change through continuity as it exists, for instance, in Southeast Asia. Each model represents a specific way of negotiating tradition and modernity. Each of them has developed particular tools for modernization and is characterized by specific tensions and challenges as well as by struggling with setbacks and imbalances.
Islam and Modernity: Nurcholish Madjid's Interpretation of Civil Society, Pluralism, Secularization, and Democracy
Authors: Bakti Andi Faisal
Published: December 2005

Debates on the applicability of the "modern" Western concepts of civil society, pluralism, secularization and democracy, together with Islam, significantly developed since the 1970s in Indonesia, in particular since the emergence of Nurcholish Madjid (hereafter Madjid). By the end of the 1980s, the Paramadina Foundation, which was established in 1986 by Madjid, among others, increasingly attracted higher middle-class individuals who claimed to adopt a progressive and open approach to Islam. Through Paramadina, Madjid, among others, developed his own idea of civil society. He is one of the most obvious champions of "neo-modernism" in Indonesia, as these ideas of both "modernism" and "traditionalism" are combined when they are relevant and suitable for society. The question addressed here is how Madjid interprets the concepts of civil society, pluralism, secularization and democracy as his main discourses? In other words, how does Madjid define and pave the way for Islamic development in Indonesia? What approaches does he use? While the concepts developed in Paramadina are basically inclusivism, pluralism, integralism, tolerance and democracy, on the way to achieving masyarakat madani (the Indonesian translation of civil society as adopted by Madjid), it seems that Madjid falls short of promoting local and global human values, international relations and communication. In fact, he adopts a cultural and nationalistic approach within the framework of Indonesian nationalism, which could lead to cultural crystallisation, particularism, localism and, eventually, atavism. These factors, however, if given a humanistic and global flavour — as set forward by the communication approach to human development — could indeed contribute to the emancipation of local citizens, from a parochial and centralized nationalism adhered to today by many Indonesian leaders. Thus, thinking globally and acting locally could be a liberating force for all.
The Problems of Religious Modernity
Authors: Tezcan Levent
Published: December 2005

This paper discusses the problems of the Islamization of modernity that are mostly ignored in the social sciences on the topic of Islam. The case study deals with a transnationalized Turkish-Islamic group of the followers of the populist theologian Said Nursi in Germany. The author presents an outline of the community character and interprets also the reactions of the community in the cross-cultural field in the aftermath of September 11, with regard to this specific culture of the group. In conclusion, he draws attention to the question of how the Islamic reformists imagine the host societies in Europe and of which symbolic repertoire has been used to connect on the current integration discourse.
Chaos and Globalization in the Middle East
Authors: LeVine Mark
Published: December 2005

This paper examines the role of economic and cultural globalization in the interaction between Muslim and European public spheres. Focusing on the dynamics of globalization at three levels — broadly, in the Muslim world and in Europe — I argue that globalization today is both more complicated and less broad than most of its proponents or critics assume. While most commentators assume that it is a primarily economic phenomenon (and so focus on the impact of supposedly increased global economic integration or technological innovation), these phenomena are concentrated largely within the mature G-8 economies and the most successful recent industrializers (such as the "Asian tigers"), leaving much of the developing world marginalized from the emerging "globalized" economy as defined in the mainstream literature. In this context it is culture that is the most powerful driver of contemporary globalization as it is experienced in the Muslims' majority world and in Muslim communities in Europe. This dynamic, in turn, has a powerful impact on how Muslim public spheres are shaped across Eurasia, particularly in the context of a transformation in the nature of globalization in the wake of September 11 towards a more militarized form of global economic interaction. An exploration of the dynamics of chaos as a defining feature of this emerging global system in the Middle East and North Africa, and Europe as well, along with a discussion of the role of anti-Semitism in contemporary discourses of globalization in the MENA and Europe, reveal the challenges to building more positive "Euro-Islamic" public spheres.
Chemical speciation terminology: chromium chemistry and cancer
Authors: Duffus J. H.
Published: December 2005

In classical toxicology, speciation of carbon is taken for granted and the carbon compounds responsible for toxicity are always described with the appropriate chemical nomenclature. By contrast, speciation of other elements is largely ignored and elements other than carbon are often condemned as toxic because of evidence relating toxicity to only a few of the chemical species in which they occur. In some cases, such as chromium, the distinction between oxidation states (chromium III and chromium VI) may be recognized as important. The fact that chromium VI may only be a toxicological problem in certain well defined forms, such as specific chromate salts that may cause nasal and lung cancer, and then only by the respiratory route of exposure, is largely ignored. Failure to consider properly chemical speciation of elements other than carbon can lead to poor use of our resources. Laws and regulations based on simple elemental analysis may wrongly condemn environmental media or products as toxic and prevent the use of important resources.
Time-dependent surface reactivity of Cd sorbed on calcite, hydroxylapatite and humic acid
Authors: Bailey E. H. , Mosselmans J. F. W. , Young S. D.
Published: December 2005

Changes in the lability and local environment of Cd sorbed onto calcite, hydroxylapatite and humic acid have been investigated as a function of time (30 min–9 months) using a combination of X-ray adsorption spectroscopy (XAS) and isotopic dilution techniques with Cd concentrations between 1 and 1000 mmol kg –1. Enhanced X-ray absorption fine structure (EXAFS) shows that precipitation of Cd carbonate was initially observed on calcite. Ageing of a 10 mmol kg–1 sample showed replacement of Cd in the fourth shell with Ca, indicating diffusion between the two phases had occurred. This diffusion appeared to be ongoing for a 10 mmol kg–1 sample even after 9 months of reaction. Only 20% of the Cd in a sample with 10 mmol kg–1 Cd remained labile after 6 months of reaction, suggesting a high degree of incorporation into the solid phase, in agreement with the XAS results. The XAS results for hydroxylapatite indicated that Cd is not fixed in the mineral lattice and Cd lability in a sample loaded with 10 mmol kg–1 Cd was ∼55% after 6 months of reaction. This indicates that a relatively high proportion of the Cd sorbed to hydroxylapatite remained as kinetically active surface species. Little change was observed in the local environment of Cd adsorbed on flocculated Ca-humate samples as a function of time and ∼75% of the Cd remained radio-labile after 6 months of reaction regardless of initial Cd loading. High lability is expected because incorporation into a solid matrix or surface precipitation of a Cd phase is less likely than with the mineral phases.
Acidic demineralization of apatites studied by scanning X-ray microradiography and microtomography
Authors: Elliott J. C. , Bollet-Quivogne F. R. G. , Anderson P. , Dowker S. E. P. , Wilson R. M. , Davis G. R.
Published: December 2005

The mineral in bones and teeth is an impure form of hydroxylapatite (HAP), the principal impurity being 2—5 wt.% carbonate. This mineral dissolves during remodelling of bone and also in dental caries as a result of the action of acids produced by osteoclasts and by bacteria, respectively. In enamel, demineralization proceeds with preferential loss of carbonate relative to phosphate. Surprisingly, in the early stages, the demineralization is subsurface. In order to facilitate the understanding of physical chemical aspects of these processes, we have undertaken studies of demineralization in model systems. We give three examples here. The first two used scanning microradiography in which the specimen is stepped across a 10—30 μm diameter X-ray beam. Intensity measurements allow calculation of the mineral mass per unit area in the X-ray path through the specimen. In the first experiment, porous HAP sections were separated from a reservoir of acidic buffer by a column initially filled with water (the diffusion length) and scanned with the X-ray beam perpendicular to the axis of the diffusion length. The rate of total loss of mineral along each profile was calculated from the scans. The rate of demineralization fell as the diffusion length increased. We believe the explanation is that the rate-controlling step is the diffusion of dissolved HAP away from the solid to the buffer reservoir. In the second experiment, demineralizing solution and water were pumped alternately, for equal lengths of time, past blocks of porous HAP or enamel. The X-ray beam was perpendicular to the exposed surface. As the rate of switching between solutions decreased, the mean rate of demineralization also fell. We propose that this effect is due to retention of acid in the pores of the HAP during the time when water flows, allowing further demineralization to take place during this time. The third study used X-ray microtomography, a form of 3D microscopy, to study the loss of mineral in compacted carbonate apatite powders. The powders were packed in six 10 mm internal diameter acrylic cylinders to a depth of 4 mm (after pressing). One end was covered with a porous polyethylene disc and each tube placed in acidic buffer for 70 days. Periodic examination by microtomography showed the development of subsurface demineralization. Infrared spectroscopy of the dissected-out surface layers showed preferential loss of carbonate over phosphate by comparison with deeper layers. Rietveld analysis of X-ray powder diffraction data showed changes in the crystallographic structures of the apatites between the initial and dissected-out apatite.
Analyses of patterns of copper and lead mineralization in human skeletons excavated from an ancient mining and smelting centre in the Jordanian desert: a reconnaissance study
Authors: Grattan J. , Abu Karaki L. , Hine D. , Toland H. , Gilbertson D. , Al-Saad Z. , Pyatt B.
Published: December 2005

In this reconnaissance study, skeletal materials from people, dating from ∼1500 B.P., who lived by or worked at the ancient copper mines and furnaces of the Wadi Faynan in southern Jordan, were analysed using atomic absorption spectrophotometry (AAS) to determine the intensities of accumulation of copper and lead in their bones. Many of the bones analysed contained concentrations of these metals which are comparable to those of modern individuals who are heavily exposed to metals through contemporary industrial processes.

Patterns of partitioning throughout the skeleton of a number of individuals were also studied. These AAS data suggest that within the human organism there may be some ability to influence the patterns of accumulation of copper within the skeleton. The humerus was frequently found to contain more copper than other bones studied. Within the humerus itself, the medial epicondyle frequently contained the highest concentrations, which may indicate a significant degree of organization or control of the process. These metal concentration data together with their toxicological consequences suggest that the health of the ancient human populations must have been adversely affected by exposure during life to copper in the environment. They also point to the need for further detailed studies of metal partitioning within the bones of the human skeleton.
Fe isotope fractionation during the precipitation of ferrihydrite and transformation of ferrihydrite to goethite
Authors: Clayton R. E. , Hudson-Edwards K. A. , Malinovsky D. , Andersson P.
Published: December 2005

Ferrihydrite and goethite are amongst the most important substrates for the sorption of contaminants in soil and other environmental media. Isotopic studies of the transition elements, particularly those that exhibit more than one oxidation state and show pH- and/or redox-sensitive behaviour at low temperatures, have been shown to be potentially useful present-day and past proxies for redox (or palaeoredox) conditions. We have made preliminary investigations of Fe isotope fractionation that take place during the formation of FeIII (oxy)hydroxides (FeIIIox) from an aqueous FeIII(NO3)3 solution (FeIIIaq) under laboratory conditions. We have attempted to keep the chemical system simple by excluding 'vital effects' and major changes in redox through the maintenance of abiotic conditions and use of FeIIIaq. Isotopic measurements (56Fe/54Fe, 57Fe/54Fe) of the FeIII(NO3)3 stock solution, the original ferrihydrite and the mixed ferrihydrite/goethite-supernatant FeIIIaq 'pairs' were carried out using a double focusing multicollector inductively coupled plasma mass spectrometer. The results reveal an apparent systematic variation indicating larger ΔFeIIIaq—FeIIIox with decrease in the ferrihydrite:goethite ratio, which reflects the time allowed for isotopic exchange. These values range from virtually zero (0.03%) after 24 h to 0.30% after 70 h. In each FeIIIox-FeIIIaq 'pair' the lighter Fe isotope is partitioned into the FeIIIox, leaving the FeIIIaq isotopically heavier. The observed fractionation reflects isotopic exchange of Fe between the FeIIIox and FeIIIaq upon at least a two step transition of ferrihydrite to goethite.
Spatial relationship between arsenic in drinking water and Mycobacterium ulcerans infection in the Amansie West district, Ghana
Authors: Duker A. A. , Carranza E. J. M. , Hale M.
Published: December 2005

This paper hypothesizes that arsenic in drinking water indirectly contributes to Buruli ulcer (BU), a skin disease caused by Mycobacterium ulcerans (MU) infection. Samples of groundwater and surface water used as drinking water by the population in Ghana's Amansie West district (part of which has a high prevalence of BU), were collected near rural settlements and analysed for arsenic. Arsenic concentration levels per settlement were compared with BU prevalence. A positive exposure-response relationship was obtained between arsenic in surface water and BU (r2 = 0.82). However, there is no significant exposure-response relation between groundwater and BU.
Aqueous exposure and uptake of arsenic by riverside communities affected by mining contamination in the Río Pilcomayo basin, Bolivia
Authors: Archer J. , Hudson-Edwards K. A. , Preston D. A. , Howarth R. J. , Linge K.
Published: December 2005

The headwaters of the Río Pilcomayo drain the Cerro Rico de Potosí precious metal-polymetallic tin deposits of southern Bolivia. Mining of these deposits has taken place for around 500 years, leading to severe contamination of the Pilcomayo's waters and sediments for at least 200 km downstream. Communities living downstream of the mines and processing mills rely on the river water for irrigation, washing and occasionally, cooking and drinking, although most communities take their drinking water from springs located in the mountains above their village. This investigation focuses on arsenic exposure in people living in riverside communities up to 150 km downstream of the source. Sampling took place in April–May 2003 (dry season) and was repeated in January–March 2004 (wet season) in five communities: El Molino, Tasapampa, Tuero Chico, Sotomayor and Cota. Cota was the control in 2003 and again in 2004; a nearby city, Sucre, and several locations in the UK were also used as controls in 2004. Drinking, irrigation and river waters, hair and urine samples were collected in each community, digested where appropriate and analysed for As using ICP-MS. Arsenic concentrations in drinking waters ranged 0.2–112 μg 1–1, irrigation water 0.6–329 μg 1–1, river waters 0.9–12,800 μg 1–1, hair 37–2110 μg kg–1 and urine 11–891 μg 1–1. All but one drinking water sample was found to contain As below the World Health Organization recommended guideline of 10 μg 1–1, although a number of irrigation and river water concentrations were above Canadian and Bolivian guidelines. Many As concentrations in the hair and urine samples from this study exceeded published values for non-occupationally exposed subjects. Analysis of mean concentration values for all media types showed that there were no statistically significant differences between the control locations and the communities exposed to known As contamination, suggesting that the source of As may not be mining-related. Arsenic concentration appears to increase as a function of age in hair samples from males and females older than 30 years. Male volunteers over the age of 35 showed increasing urine-As concentrations as a function of age, whereas the opposite was true for the females.
Electrokinetic generation of reactive iron-rich barriers in wet sediments: implications for contaminated land management
Authors: Faulkner D. W. S. , Hopkinson L. , Cundy A. B.
Published: December 2005

Here we describe preliminary research into the in situ electrokinetic generation of continuous iron-rich precipitates to act as sub-surface barriers for the containment of contaminated sites. This is achieved using sacrificial iron electrodes emplaced either side of a soil/sediment mass to introduce iron into the system, and their dissolution and re-precipitation under the influence of an applied (DC) electric field. Continuous vertical and horizontal iron-rich bands (up to 2 cm thick) have been generated over a timescale of 300—500 h, at voltages of <5 V with an electrode separation of between 15 and 30 cm. The thickness of the iron-rich band increases as the applied voltage is increased. Geotechnical tests in sand indicate that the iron-rich band produced is practically impervious (coefficient of permeability of 10—9 ms—1 or less), and has significant mechanical strength (unconfined compressive strength of 10.8 N mm—2). By monitoring the current, the integrity of the iron-rich band may be assessed, and by continued application of current, the barrier may 'self heal'. The iron-rich barrier is composed of amorphous iron, goethite, lepidocrocite, maghemite and native iron.
Redox processes in a eutrophic coal-mine lake
Authors: Roman-Ross G. , Charlet L. , Tisserand D. , Glemme M.
Published: December 2005

The water column chemistry of lake St Eloy (St Eloy-les Mines, Allier, France) was monitored over a period of a year. This is a small stratified lake created by subsidence of an underground coal mine. The results show a permanent stratification and the development of two water bodies with contrasting chemistry. The superficial oxic layer (i.e. the upper 5 m) is of high water quality and the water, not affected by seasonal changes, is suitable as a source of drinking water. In contrast, the deeper layer is permanently anoxic and the waters have a conductivity which is six times greater than in the epilimnion. Due to density difference and the small size of the lake, no turn-over occurs and all elements that diffuse from bottom sediments are strongly concentrated in the hypolimnion. Arsenic concentrations are very low in the epilimnion, but they increase quickly with depth below the oxycline, to reach up to 7 μm below 8 m depth. Different solid phases could control the fate of arsenic in this lake such as gypsum for As(V) in the hypolimnion, mackinawite for As(V) and As(III) in the hypolimnion, and close to the oxycline, Fe(III) oxyhydroxides are possible hosts for both As(III) and As(V).
Hydrochemical associations and depth profiles of arsenic and fluoride in Quaternary loess aquifers of northern Argentina
Authors: Warren C. , Burgess W. G. , Garcia M. G.
Published: December 2005

Arsenic and fluoride in groundwater from Quaternary loess deposits in Argentina pose major health concerns. Common sources for arsenic and fluoride have been suggested but the processes of mobilization are disputed, and distributions in groundwater are largely unresolved at a sample density >1/50 km2. At Los Pereyras in Tucumán Province, northern Argentina, we have evaluated distributions and hydrochemical associations of arsenic and fluoride with a sample density of 0.75 per km2 over an area of 75 km2, to a depth of 230 m. Groundwater in the loess is oxic and alkaline. Fluoride is restricted to the upper 20 m of the Quaternary loess, where it reaches 8.3 mg/1. Arsenic has a vertical layering consistent with that of fluoride, ranging from 20 to 760 μg/1 in the upper 20 m and 58—163 μg/l below this. There are two sources of arsenic, one unrelated to the fluoride source. Positive correlations between arsenic and fluoride with pH, but not with alkalinity, support desorption from iron oxyhydroxides as the likely mechanism of release to groundwater for arsenic and fluoride, rather than the weathering of silicate minerals. Stratigraphic and/or palaeohydrological controls may explain the observed depth distributions within the loess aquifer.
Arsenic-bearing smectite from the geothermal environment
Authors: Pascua C. , Charnock J. , Polya D. A. , Sato T. , Yokoyama S. , Minato M.
Published: December 2005

Arsenic-rich scales are widely associated with geothermal fields and constitute a potential hazard to human health. Such arsenic has hitherto been reported to be almost exclusively hosted by sulphide or oxide phases or occurring as surface species. We report here, however, the occurrence of an arsenic-rich (1500 to 4000 mg kg—1 As) smectite from geothermal precipitates from a geothermal field in northwestern Japan and present evidence that the arsenic is predominantly hosted within this silicate mineral.

Consistently ∼80% of the total arsenic determined in these geothermal precipitates was found by selective chemical extractions to be associated with an operationally defined clay mineral fraction, with lesser proportions being associated with operationally defined amorphous silica, Fe oxide and sulphide fractions. Analysis by XRD, ATR IR and XRF showed the clay fraction to be dominated by Mg-rich trioctahedral smectite.

Arsenic K-edge XAS spectra of the smectite suggested the dominance of As(III)-O coordinated species with significant contributions from As(V)-O coordinated species. Both XPS and a magnesium chloride chemical extraction indicated minimal adsorption of arsenic on smectite surfaces suggesting that the arsenic was predominantly either dissolved within the smectite or occurred within mineral occlusions. No such occlusions greater than 1 μm in size were observed in the As-rich smectites.

The potential occurrence of arsenic-bearing clays should be considered when determining remediation strategies for geothermal environments or evaluating risks associated with the industrial usage of geothermal precipitates.
An agenda for thinking about ‘race’ in development
Authors: Kothari Uma
Published: December 2005

This paper reveals some of the silences about ‘race’ in development ideologies, institutions and practices. It suggests that these mask the perpetuation of a racialized discourse in development, its complicity with broader historical and contemporary racial projects and the effects of ‘race’ on the processes and consequences of development. The paper provides an agenda for understanding development in terms of ‘race’ and identifies three potential areas for further investigation. The first is the continuing legacy of colonial constructions and the persistence of forms of racial difference and hierarchy in development. The second concerns the power of whiteness and specifically how authority, expertise and knowledge become racially symbolized. The third area for further examination is how ‘race’ is disguised through the use of specialized terminology and criteria in accounting for poverty and social exclusion. The paper concludes by suggesting that debates around multiculturalism and anti-racism could inform a shift away from racialized representations and inequalities prevailing in development.
Anti-racism, deconstruction and ‘overdevelopment’
Authors: Power Marcus
Published: December 2005

This paper explores the connections between colonialism and development in order to understand more clearly how discourses on North-South relations continue to be imbued with the imperial representations that preceded them. Beginning with a concern to examine how anti-racism can inform our understanding of the spaces of international development, the paper interrogates the colonial heritage of development studies and related disciplines and speculates on the possibility and necessity of disciplinary decolonization. Using the specific example of Portuguese imperial discourses of development in the 1950s and the 1960s, and the emergence of the heavily racialized ‘science’ of Lusotropicalism, the paper then examines the importance of deconstruction as a way of understanding the différance between colonialism and development in the Lusophone empire. The paper goes on to examine the particular example of postcolonial Mozambique, exploring the ways in which, between 1975 and 1988, Mozambicans struggled to acknowledge and deal with racism in postcolonial society, particularly in the context of Mozambique’s growing relationship with the World Bank in the mid-1980s. The paper concludes by suggesting that a more direct focus on ‘overdevelopment’ rather than just ‘underdevelopment’ may be one important (if neglected) way forward in ending the silences around ‘race’ and racism in development studies.
The ‘gender lens’: a racial blinder?
Authors: White Sarah C.
Published: December 2005

While gender is highly visible in development theory and practice, race is rarely mentioned. This paper asks why this is, and how far Gender and Development (GAD) itself is implicated in the lack of recognition of race. The paper begins by acknowledging the complexity of the question: that race, gender and development are all contested terms and represent continuing sites of struggle. It then explores various aspects of ‘race in GAD’. These include: the charge of cultural imperialism; the false simplicity in the labelling of ‘women’, which masks the very different terms on which ‘third’and ‘first’world women were ‘brought into’development; and the failure of core GAD frameworks to recognize black feminist thought, so critically limiting their analytical power. The paper then goes on to discuss the racial marking of expertise in development and the ambivalent ways in which value is assigned through this. The paper concludes by reflecting on the interplay of identities in development planning and what this reveals of the implication of development more broadly in the construction of social difference.
Racism, migration and development: the foundations of planetary order
Authors: Duffield Mark
Published: December 2005

Using Foucault’s conception of racism and sovereign power as a point of departure, this paper examines an expansive and centralizing security architecture that interconnects the policing of international migration, the promotion of domestic social cohesion and the search for overseas development. Emerging with decolonization, the basis of this interdependence is a racial discourse that now takes a sociocultural rather than an outwardly biological idiom. The paper argues that this shift presages the collapse of the national and international divide within political imagination. It examines sustainable development as a biopolitical technology for containing a non-insured, that is, self-reliant species-life. Since the end of the cold war, and reinforced by the war on terrorism, the interconnection between racism, migration and development has underpinned an emerging regime of planetary order. While international support for the territorial integrity of the underdeveloped state remains, within such states sovereignty over life has become negotiable and contingent. On this basis, new possibilities present themselves to centralize power through directly linking the local with the local at the level of population. The paper concludes by examining the tendency towards biopolitical tyranny within planetary order.
A Method to Predict the Heat Generation in a Rubber Spring Used in the Railway Industry
Authors: Luo R K , Wu W X , Mortel W J
Published: December 2005

An integrated real-time simulation and experimental programme has been carried out on an anti-vibration part used in the railway industry. This work, which was done at the authors' Technical Centre, was designed to ensure that any temperature rise inside an anti-vibration part does not exceed the design requirement in accelerated fatigue tests. Real-time simulation and testing have the advantages of giving the maximum temperature change when an anti-vibration component reaches a steady state and the time duration for each stage of the whole process. It is found from both testing and simulation that the energy loss per cycle of the rubber spring, under fixed dynamic amplitude, does not depend on the loading frequency. Therefore, the energy loss per cycle can be more easily obtained using a conventional quasi-static loading procedure, to reduce the cost and the time, than from conducting more complicated dynamic tests.

Key rubber parameters obtained from the authors' material testing laboratory are presented here as important references for similar applications in railway industries. It is shown that this methodology is reliable and can be used to evaluate the temperature effects caused by dynamic loading.
Design and Analysis of Magnetorheological Dampers for Train Suspension
Authors: Lau Y K , Liao W H
Published: December 2005

This article aims at designing a magnetorheological (MR) fluid damper that is suitable for a semi-active train suspension system in order to improve its ride quality. A double-ended MR damper is designed, fabricated, and tested. Simulation is carried out by integrating the MR damper model in the secondary suspension of a full-scale railway vehicle model. The feasibility and effectiveness of the semi-active train suspension system with the developed MR dampers are investigated by comparing the controlled performances of the MR suspension system with different passive suspension systems. The results show that the semi-active suspension with the developed MR dampers can substantially improve the ride quality of the passengers.
Vehicle-Track Dynamic Simulations of a Locomotive Considering Wheelset Structural Flexibility and Comparison with Measurements
Authors: Chaar N , Berg M
Published: December 2005

Wheelset structural flexibility, that is the elastic deformation of the wheelset as a structure, can significantly influence the vehicle-track dynamic interaction. In this paper on-track simulations considering flexible wheelsets, modelled through eigenmodes derived from a finite element model, are presented and compared with on-track measurements. The effects of the wheelset structural flexibility on track forces, in the frequency range 0-100 Hz, are investigated. Results from parametric studies are also presented. The present application is a Swedish Rc7 locomotive having rather slender wheelsets. It is shown that both lateral and vertical track forces are significantly influenced by the wheelset flexibility and that the agreement with measurements is fairly good. The wheelset flexibility increases the lateral track forces. The track representation in the present context is important and the used so-called moving track model needs improvements.
Development of a Methodology to Calculate Stresses in Track Components
Authors: Naudé F P , Fröhling R D , Theron N J
Published: December 2005

The analytical model being used by Spoornet to calculate rail stresses on railway track for the past three decades was revisited and improved. The modifications include the incorporation of current best practices and presenting the engineer with guidelines on how to determine input parameters, which are normally difficult to obtain.

The most sensitive parameters were investigated, and experimental results, as well as modern modelling methods, were used to establish nominal input values and guidelines for determining such values.

The improved analytical model provides engineers with a suitably accurate tool for calculating rail and track component stresses, without the need to build detailed models of the track under investigation.
Study of Critical Sections in Catenary Systems During Multiple Pantograph Operation
Authors: Harèll P , Drugge L , Reijm M
Published: December 2005

To improve the dynamic behaviour of a catenary system, the sections that limit the speed have to be found. A survey was made to gather information about critical sections of the catenary-pantograph system. Interviews with personnel at the Swedish National Rail Administration were performed and problem areas that need consideration were found and are presented. The purpose of this study was to find out how much of these critical sections affect the system and to suggest improvements to the design. Section overlaps and section insulators, both in combination with the usage of multiple pantographs, were modelled, and simulations have been performed at different speeds and for different catenary systems. As a result of this research, a better base could be built on how to ease the operation with multiple pantographs.
How Do Hospitals Respond to Price Changes?
Authors: Dafny Leemore S
Published: December 2005

This paper examines hospital responses to changes in diagnosis-specific prices by exploiting a 1988 policy reform that generated large price changes for 43 percent of Medicare admissions. I find hospitals responded primarily by “upcoding” patients to diagnosis codes with the largest price increases. This response was particularly strong among for-profit hospitals. I find little evidence hospitals increased the volume of admissions differentially for diagnoses subject to the largest price increases, despite the financial incentive to do so. Neither did they increase intensity or quality of care in these diagnoses, suggesting hospitals do not compete for patients at the diagnosis level.
A Model of Positive Self-Image in Subjective Assessments
Authors: Santos-Pinto Luís , Sobel Joel
Published: December 2005

This paper suggests a mechanism that describes individuals' positive self-image in subjective assessments of their relative abilities. The mechanism assumes individuals have heterogeneous production functions that determine ability as a function of multiple skills; make skill-enhancing investments with the goal of maximizing their ability; and make ability comparisons using their own production function. Within this framework, the paper provides conditions under which there is positive self-image. Positive self-image is increasing in the ease of the task, the number of different skills needed for the task, and the variability of production technologies in the population.
Does Increasing Women's Schooling Raise the Schooling of the Next Generation? Reply
Authors: Behrman Jere R , Rosenzweig Mark R
Published: December 2005

We reassess the empirical robustness of the empirical findings in Jere R. Berhman and Mark R. Rosenzweig (2002) using new information on schooling which was collected and coded independently of codings carried out by both Kate Antonovics and Arthur Goldberger, and Berhmamn and Rosenzweig. We conclude that the independently coded data and the codings by Antonovics and Goldberger provide additional support for Behrman and Rosenzweig's original results showing that the positive cross-sectional relationship between a mother's schooling and her child's schooling is not robust to controls for unmeasured, intergenerationally correlated endowments, while the positive effect of paternal schooling is robust.
Fact-Free Learning
Authors: Aragones Enriqueta , Gilboa Itzhak , Postlewaite Andrew , Schmeidler David
Published: December 2005

People may be surprised to notice certain regularities that hold in existing knowledge they have had for some time. That is, they may learn without getting new factual information. We argue that this can be partly explained by computational complexity. We show that, given a knowledge base, finding a small set of variables that obtain a certain value of R2is computationally hard, in the sense that this term is used in computer science. We discuss some of the implications of this result and of fact-free learning in general.