bluuebunny/crossref_metadata_2025 huggingface dataset:
The 21 May 2003 Zemmouri (Algeria) earthquake Mw 6.8: Relocation and aftershock sequence analysis
Authors: Bounif A. , Dorbath C. , Ayadi A. , Meghraoui M. , Beldjoudi H. , Laouami N. , Frogneux M. , Slimani A. , Alasset P. J. , Kharroubi A. , Ousadou F. , Chikh M. , Harbi A. , Larbes S. , Maouche S.
Published: October 2004

A strong earthquake (Mw 6.8) struck the coastal region east of Algiers and the Tell Atlas of Algeria on 21 May, 2003 and was responsible of severe damage and about 2400 casualties. The coastal mainshock was followed by a large number of aftershocks, the largest reaching Mw 5.8 on 27 May 2003. We study the mainshock, first major aftershocks and about 900 events recorded by temporary seismic stations using master‐event approach and double‐difference (DD) methods. Although the seismic station array has a large gap coverage, the DD algorithm provides with an accurate aftershocks location. The mainshock hypocenter relocation is determined using three major aftershocks (5.0 ≤ Mw ≤ 5.8) chosen as master events. The new mainshock location shifted on the coastline (36.83N, 3.65E) at 8–10 km depth. Seismic events extend to about 16‐km‐depth and form a N 55°–60°E trending and 45°–55°SE dipping fault geometry. Up to now, it is the unique among the recently studied seismic events of the Tell Atlas of Algeria. Mainshock and aftershocks relocation, the thrust focal mechanism (Harvard CMT: N 57°, 44°SE dip, 71 rake) and the seismic moment 2.86 1019Nm, infer a 50‐km‐long fault rupture that may appear at the sea bottom at 6 to 12 km offshore north of the coastline. The Zemmouri earthquake occurred along the complex thrust‐and‐fold system of the Tell Atlas and provides with new constraints on the earthquake hazard evaluation in northern Algeria.
Melting features along the Ryukyu slab tear, beneath the southwestern Okinawa Trough
Authors: Lin Jing‐Yi , Hsu Shu‐Kun , Sibuet Jean‐Claude
Published: October 2004

The present‐day active volcanic front associated with the Ryukyu subduction zone extends from Japan to the Ilan plain (northern Taiwan) and is located within the Okinawa Trough, 80–100 km above the Ryukyu slab. An abnormal amount of arc volcanism, which consists of basalt, andesite and rhyolite occurs within the southwestern Okinawa Trough, above a slab tear of the Ryukyu subduction zone (CBVT). The power spectrum analysis of magnetic data shows the occurrence of a thin crust above the slab tear and a thick crust beneath this volcanic area. We suggest that an excess of H2O‐rich fluid might occur at the slab tear and might increase the melt flux. Both are conveyed obliquely to the uppermost mantle and lower crust CBVT magmas. After interactions, basaltic magmas would rise up, accounting for the contrast of magnetization between this volcanic body and the adjacent OT crust.
Seismic attenuation and mantle wedge temperatures in the Alaska subduction zone
Authors: Stachnik Joshua C. , Abers Geoffrey A. , Christensen Douglas H.
Published: October 2004

Anelastic loss of seismic wave energy, or seismic attenuation (1/Q), provides a proxy for temperature under certain conditions. TheQstructure of the upper mantle beneath central Alaska is imaged here at high resolution, an active subduction zone where arc volcanism is absent, to investigate mantle thermal structure. The recent Broadband Experiment Across the Alaska Range (BEAAR) provides the first dense broadband seismic coverage of this region. The spectra ofPandSHwaves for regional earthquakes are inverted for path averaged attenuation operators between 0.5 and 20 Hz, along with earthquake source parameters. These measurements fit waveforms significantly better when the frequency dependence ofQis taken into account, and in the mantle, frequency dependence lies close to laboratory values. Inverting these measurements for spatial variations inQreveals a highly attenuating wedge, withQ< 150 forSwaves at 1 Hz, and a low‐attenuation slab, withQ> 500, assuming frequency dependence. Comparison withPresults shows that attenuation in bulk modulus is negligible within the low‐Qwedge, as expected for thermally activated attenuation mechanisms. Bulk attenuation is significant in the overlying crust and subducting plate, indicating thatQmust be controlled by other processes. The shallowest part of the wedge shows little attenuation, as expected for a cold viscous nose that is not involved in wedge corner flow. Overall, the spatial pattern ofQbeneath Alaska is qualitatively similar to other subduction zones, although the highest wedge attenuation is about a factor of 2 lower. TheQvalues imply that temperatures exceed 1200°C in the wedge, on the basis of recent laboratory‐based calibrations for dry peridotite. These temperatures are 100–150°C colder than we infer beneath Japan or the Andes, possibly explaining the absence of arc volcanism in central Alaska.
A biweekly mode in the equatorial Indian Ocean
Authors: Sengupta Debasis , Senan R. , Murty V. S. N. , Fernando V.
Published: October 2004

The National Institute of Oceanography, Goa, deployed moorings with several subsurface current meters at 0°, 93°E (in February 2000) and 0°, 83°E (in December 2000) in the eastern Indian Ocean. Observed meridional current at all depths has a 10‐ to 20‐day (or biweekly) variability that is distinct from longer period (20‐ to 60‐day) subseasonal variability. Lags between different instruments suggest the presence of groups of westward and vertically propagating biweekly waves with zonal wavelength in the range 2100 to 6100 km. We use an ocean model forced by high‐resolution scatterometer wind stress to show that the observed biweekly variability is due to equatorially trapped mixed Rossby‐gravity waves generated by subseasonal variability of winds. We demonstrate that quasi‐biweekly fluctuations of surface meridional wind stress resonantly excite ocean waves with westward and upward phase propagation, with a typical period of 14 days and zonal wavelength of 3000–4500 km. The biweekly wave is associated with fluctuating upwelling/downwelling in the equatorial Indian Ocean, with amplitude of 2–3 m per day located 2–3 away from the equator. Possible reasons for eastward intensification of biweekly energy are discussed.
A comparison of multiple proxies for export production in the equatorial Pacific
Authors: Averyt Kristen B. , Paytan Adina
Published: October 2004

Several commonly used paleoproductivity proxies were compared to evaluate the validity of assumptions and limitations associated with each proxy. Export production fluxes (Cexport) over glacial‐interglacial timescales were calculated from previously developed, proxy‐specific algorithms at TTN013‐pc72 and TTN013‐pc114, both located in the equatorial Pacific. Comparison of data from the same core intervals yields conflicting results despite calibrations based on the same core top samples. The periodicity of marine barite, excess Ba, and excess Al‐based Cexport records is similar. The relative magnitude of Cexport when calculated using excess Ba and algorithms based on sediment trap data is significantly different than records based on core top calibrations, particularly during glacial intervals. At both sites, bulk sedimentary Al/Ti and Ba/Ti ratios covary; however, these ratios do not correspond with the downcore records of their respective excess concentrations (and their accumulation rates), or with contemporaneous records based on marine barite, excess Ba, and excess Al accumulation. Although downcore records based on sediment mass accumulation rates may be compromised by sediment focusing, this process cannot explain all the differences observed among the various data sets presented here. This implies that some or all of these proxies do not exclusively respond to changes in export production. The contradictions among these data highlight the importance of addressing inconsistencies among paleoproxies and re‐examining assumptions imbedded in proxy fundamentals, prior to applying paleoproductivity proxies and interpreting paleoceanographic records.
National Environmental Goals in Search of Local Institutions
Authors: Hovik Sissel , Reitan Marit
Published: October 2004

This paper is an examination of Norway's national strategy for developing local environmental policies and institutions from the late 1980s to the present, and how this strategy has been influenced by changes in the dynamic between central government and local political institutions. It is argued that the strategy has changed during the period of study, shifting from a strong emphasis on the development of local institutions to an emphasis on the delegation of responsibilities from central government to local governing bodies. This new policy of delegation has been advanced at a time when municipalities are suffering from a weakened institutional capacity for environmental policy-making because of changes in the country's overall regulatory approach. The authors argue that this approach, which first and foremost has been motivated by national, macroeconomic objectives and the role of local government in service production, is inconsistent with the government's ambitions of a more important role for local government in environmental policy. The nature of environmental challenges, which often cut across political and administrative borders and often involve conflicts between different levels of government, suggests that local institutions are crucially important within the environmental policy domain.
Dilemmas of Implementation: ‘Integration’ and ‘Participation’ in Norwegian and Scottish Local Government
Authors: Abram Simone , Cowell Richard
Published: October 2004

Recent shifts in local governance across Europe have emphasised ‘more public participation’ and ‘closer integration’ between the bodies involved in policy formulation and delivery. Researchers have only started to examine the mutual compatibility of these agendas. The focus of this analysis is a cross-national comparison between Norway and Scotland, using ethnographic methods to chart how various actors have used strategic planning ( kommuneplan in Norway, community plans in Scotland) simultaneously to promote participation and integration. A study of local implementation practices reveals tensions between these agendas, but also the various contextually embedded ways in which local officers, politicians, and publics talk past, negotiate, or otherwise manage the problem. These are manifest in the balance between participatory and integrative activities in drawing up the plans; in the role of elected members; in combining steering and representative roles for partnerships; and in pressures for rationalisation. In the final analysis, we argue that these problems cannot simply be considered as local managerial muddles, but as reflecting deeper tendencies in ‘Third Way’ politics and the practical consequences of its emphasis on ‘what works’.
Differences between First-Generation and Second-Generation Ethnic Start-ups: Implications for a New Support Policy
Authors: Masurel Enno , Nijkamp Peter
Published: October 2004

In this paper we study the extent to which first-generation ethnic entrepreneurs show a different motivation to start their own businesses from their second-generation counterparts. Our research project contains findings from empirical fieldwork among Turkish entrepreneurs in the Greater Amsterdam area. First-generation ethnic entrepreneurs appear to be more motivated by discrimination, problems with the transferability of their diplomas, and the goal of obtaining status, compared with their second-generation counterparts. The latter group derives more motivation from blocked promotion to start their own businesses. We found no other differences between these groups in their motives for starting up, that is, unemployment; need for achievement; making use of market opportunities; striving for independence; and using their own special talents. The reasons for finding fewer differences than expected between the two generations are discussed extensively in our paper. Having shown what the differences are between the two generations, we are able to sketch the contours for a new support policy for ethnic entrepreneurs. This new support policy is based on the need to pay attention both to the motives for starting up business and to the necessary preparatory activities. This lesson should be translated into a number of projects and programmes, as ethnic entrepreneurship is a multifaceted phenomenon with at least as many sides as there are ethnic groups.
The Contradictions of Urban Policy: The Case of the Single Regeneration Budget in London
Authors: Ball Michael , Maginn Paul J
Published: October 2004

The Single Regeneration Budget, at its inception, was heralded as a breakthrough in English urban policy. It consolidated the emphasis on unified regeneration projects in which local authorities and communities played key roles. We examine empirical evidence of successful London bids from the programme to determine whether it lived up to its claims, in the city that gained the largest share of the budget. Drawing on headline funding and projected output data from all six annual bidding rounds, we conclude that the programme had disparate aims that were based more on contemporary political issues than on a coherent long-term strategy. Furthermore, the aims of individual projects were often unrealistic, so that monitoring and management were likely to fall short of what was planned. On the basis of this evidence, a wider discussion criticises the general drift of urban policy from the 1970s towards ‘locality managerialism’—a belief that problems of dilapidation and deprivation have predominantly spatial causes and can be tackled through area-based programmes.
Comparison of Isotope Dilution and a Portable Anodic Stripping Voltammetry Device for Blood Lead Measurements: Source of Lead in Blood of Female Adults from Bangalore
Authors: Gulson Brian L. , Venkatesh Thuppil , Palmer Jacqueline , D'Souza Herman Suil , Korsch Michael
Published: October 2004

We have analyzed blood samples from 20 pregnant Indian women from the city of Bangalore to assess the suitability of Indian subjects in a pregnancy study and assess the feasibility of using the lead isotopic method for determining sources and pathways of lead in Indian subjects. Blood lead concentrations range from 4.3 to 20.1 μg dL−1 with a geometric mean of 9.0 μg dL−1. There is excellent agreement between the isotope dilution measurements for blood lead concentration and those obtained by anodic stripping voltammetry (ASV; R2 0.96, P < 0.0001). A paired t-test shows that there is a statistically significant difference (p 0.008) with the results for ASV being approximately 6% higher than for those obtained by isotope dilution. The 206Pb/204Pb ratios range from 17.12 to 17.75 and showed major differences to the lead isotopic ratios that have been measured in Indian lead–zinc mineral deposits. It is suggested that lead in petrol is a major source of lead in the blood of Bangalore women.
Chemical Speciation of Hg(II) with Environmental Inorganic Ligands
Authors: Powell Kipton J. , Brown Paul L. , Byrne Robert H. , Gajda Tamas , Hefter Glenn , Sjöberg Staffan , Wanner Hans
Published: October 2004

Abstract
Complex formation between Hg(ii) and the common environmental ligands Cl−, OH−, CO32−, SO42−, and PO43− can have profound effects on Hg(ii) speciation in natural waters with low concentrations of organic matter. Hg(ii) is labile, so its distribution among these inorganic ligands can be estimated by numerical modelling if reliable values for the relevant stability constants are available. A summary of critically reviewed constants and related thermodynamic data is presented. Recommended values of log10βp,q,r° and the associated reaction enthalpies, ΔrHm°, valid at Im = 0 mol kg−1 and 25°C, along with the equations and specific ion interaction coefficients required to calculate log10βp,q,r values at higher ionic strengths and other temperatures are also presented.
Under typical environmental conditions Hg(ii) speciation is dominated by the reactions Hg2+ + 2Cl− ↔ HgCl2(aq) (log10β2° = 14.00 ± 0.07), Hg2+ + Cl− + H2O ↔ Hg(OH)Cl(aq) + H+ (log10β° = 4.27 ± 0.35), and Hg2+ + 2H2O ↔ Hg(OH)2(aq) + 2H+ (log10*β2° = −5.98 ± 0.06).
Risk-Based Assessment of the Impact of Aluminium on a Riverine Ecosystem
Authors: Brown Paul L. , Ferris John M.
Published: October 2004

The Dawesley Creek–Bremer River drainage system, in South Australia, is affected by the potentially costly problem of acid drainage from the Brukunga mine site. This paper contrasts geochemical model predictions of water quality with detailed measurement of water chemistry in the field. This information is also used in the ecological risk assessment code, AQUARISK, to predict the degree of ecological detriment. These predictions are then assessed against independent, field-based biomeasures of algal and bacterial communities to test the performance of the code. The study demonstrates that the assessment of ecological risk obtained using AQUARISK, when coupled with geochemical modelling, accords quite well with the independent data from the biomeasures. Results from the study also suggest that only a single water-quality guideline value is required for aluminium, the major toxicant in the Dawesley Creek–Bremer River system.
Micrometer-Resolved Binding of Lead to Iron in Urban River Sediments
Authors: Rauch Sebastien , Morrison Gregory M.
Published: October 2004

Recent developments in laser microprobes and the coupling of laser ablation (LA) to inductively coupled plasma mass spectrometry (ICP-MS) has opened up the possibility for detailed analysis of individual sediment grains and the elucidation of metal association with bulk elements and phases. Here, LA–ICP-MS is used for the micrometer-resolved, multi-element analysis of Pb and bulk elements such as Fe, Mg, Al, and Si. Normalized Pb signals show a clear association to Fe coatings at the surface of the particles.
Simultaneous Determination of Fluoroacetates, Chloroacetates, and Bromoacetates in Soil Samples by Ion Chromatography
Authors: Wang Fang , Dicinoski Greg W. , Zhu Yan , Haddad Paul R.
Published: October 2004

A comparative study was made of the chromatographic behaviour of nine haloacetic acids, namely mono-, di-, and tri-fluoroacetate (MFA, DFA, and TFA, respectively); mono-, di-, and tri-chloroacetate (MCA, DCA, and TCA, respectively); and mono-, di- and tri-bromoacetate (MBA, DBA, and TBA, respectively), employing anion-exchange chromatography with suppressed conductivity and UV detection, using a Dionex AS17 anion-exchange column employed with a potassium hydroxide gradient (via a Dionex EG40 Eluent Generator). All nine haloacetic acids were completely separated under the optimized gradient elution conditions, and use of selective detection methods or pretreatment with an OnGuard II Ag cartridge resulted in the elimination of interferences from chloride and bromide occurring in soil samples. The procedure for the simultaneous determination of the nine haloacetic acids was simple and rapid. The method detection limits for MFA, DFA, TFA, MCA, DCA, TCA, MBA, DBA, and TBA were 21, 40, 40, 28, 48, 86, 67, 55, and 160 μg L−1, respectively. Application of this method to the determination of haloacetic acids in real soil samples is illustrated.
Microbial Reduction of Hexavalent Chromium in Landfill Leachate
Authors: Li Yarong , Low Gary K.-C. , Lei Ying , Halim Cheryl E. , Amal Rose
Published: October 2004

Landfill leachates were found to exhibit reducing properties whereby chromium(vi) was converted into chromium(iii). The reduction is attributed to a microbial process in the presence of high concentrations of organic materials in the leachates. Nonputrescible landfill leachate (NPLL) was found to reduce CrVI to a lesser extent than the municipal landfill leachate (MLL). Microbial reduction of CrVI was also found to occur under alkaline conditions in extracts from a cementitious waste. A 55% reduction of CrVI was achieved by enriching the extract with bacteria and organic material.
Preliminary Evaluation of Dual Acidic Potassium Permanganate and Tris(2,2′-bipyridyl)ruthenium(II) Chemiluminescence Detection for the HPLC Determination of Papaver somniferum Alkaloids
Authors: Lenehan Claire E. , Barnett Neil W. , Lewis Simon W. , Essery Kevin M.
Published: October 2004

This paper describes a dual chemiluminescence reagent for the determination of the opiate alkaloids morphine, codeine, oripavine, and thebaine in Papaver somniferum extracts. Detection was achieved using a mixture of acidic potassium permanganate and tris(2,2′-bipyridyl)ruthenium(ii), where the former acted as both the oxidant for the latter and as a chemiluminescence reagent in its own right. The analytes were separated on a C8 column using ion-pairing HPLC. The application of the mixed reagent detection compared favourably with results obtained using standard HPLC methodology. Detection limits for the alkaloids were 10−6, 5 × 10−7, 3 × 10−6, and 2 × 10−6 mol L−1 for morphine, codeine, oripavine, and thebaine, respectively.
Dynamic Speciation Analysis of Heterogeneous Metal Complexes with Natural Ligands by Stripping Chronopotentiometry at Scanned Deposition Potential (SSCP)
Authors: Town Raewyn M. , van Leeuwen Herman P.
Published: October 2004

Stripping chronopotentiometry at scanned deposition potential (SSCP) allows chemical heterogeneity in metal speciation to be unambiguously identified. In the labile regime, use of the Freundlich binding isotherm allows straightforward determination of parameters to describe the apparent stability and heterogeneity of metal complexes with humic substances. The extent of heterogeneity of metal binding by several humic substances follows the order Cu(ii) >> Pb(ii) > Cd(ii). The lability of metal complexes decreases from the foot to the top of the wave, and the greater the degree of heterogeneity, the more readily lability is lost. In the kinetic current regime, the Koutecký–Koryta approximation allows an expression to be obtained for the SSCP wave that provides a good estimate of the experimental data for metal complexes with moderate degrees of heterogeneity.
Uptake of Neutral Metal Complexes by a Green Alga: Influence of pH and Humic Substances
Authors: Boullemant Amiel , Vigneault Bernard , Fortin Claude , Campbell Peter G. C.
Published: October 2004

We have examined the influence of pH and a natural humic acid on the short-term uptake (<40 min) of a neutral, lipophilic metal complex by a unicellular freshwater alga, Pseudokirchneriella subcapitata. Cadmium diethyldithiocarbamate ([Cd(DDC)2]0) was used as a model lipophilic metal complex and Suwannee River Humic Acid (SRHA) was chosen as a representative aquatic humic acid (6.5 mg C L−1). Under the experimental conditions virtually all the Cd was expected to be present as the lipophilic complex ([Cd]T = 0.38 nM; [DDC] 1 μM; [Cd2+] <10−15 M; pH 7.0, 6.0, or 5.5). Uptake of [Cd(DDC)2]0 proved to be sensitive to pH changes. It was lower at pH 6.0 and 5.5 than at pH 7.0. To our knowledge, this is the first demonstration of reduced uptake of a lipophilic metal complex at low pH. The presence of SRHA also affected uptake, either by binding the lipophilic complex in solution and reducing its bioavailability (pH 7.0) or by increasing the permeability of the algal membrane (pH 5.5).
Speciation and Bioavailability of Trace Metals in Water: Progress Since 1982
Authors: Batley Graeme E. , Apte Simon C. , Stauber Jennifer L.
Published: October 2004

The advances in studies of trace metal speciation and bioavailability since Mark Florence’s 1982 review of the topic, published in Talanta, have been comprehensively reviewed. While the relative merits of kinetic and equilibrium approaches are still being determined, advances in the applications of stripping voltammetry, including the application of microelectrodes and an appreciation of detection windows in both CSV and ASV, have been matched by the introduction of new dynamic techniques including diffusive gradients in thin films (DGTs), permeation liquid membranes (PLMs), and improved applications of chelating resins. There have also been improvements in equilibrium techniques such as ion-selective electrodes and Donnan dialysis. The ability of geochemical speciation models to predict metal complexation by natural organic matter has greatly improved, yet the models still require validation against field measurements. More reliable and relevant bioassays have been developed using sensitive species such as algae and bacteria, and improved protocols are eliminating uncertainties particularly due to problems with high cell densities, and are allowing more useful comparisons with chemically estimated bioavailability. While the free-ion activity model has provided an improved interpretation of the relative toxicities observed with different metal species, its extension to the biotic ligand model is leading to better predictions of acute effects at least on higher organisms. The extension of such approaches to studies of chronic effects at ‘natural’ concentrations using unicellular organisms remains a challenge, as does the evaluation of whether such approaches are simplified limiting cases of a more dynamic natural situation where chemical reactivity and rates of metal transport could be important.
Validation and Application of Wipe Sampling and Portable XRF Analysis as an On-Site Screening Method for Assessment of Deposited Aerosols in Workplaces
Authors: Nygren Olle , Aspman Oscar
Published: October 2004

Emission of metals in the form of aerosols constitutes a potential health risk in many working environments. Determination of deposited aerosols can be a useful tool for the assessment of aerosol distribution in the workplace and be a complement to more traditional exposure measurements. X-Ray fluorescence (XRF) is a common analytical method for elemental analysis of aerosols. By collection of deposited aerosols by wipe sampling followed by XRF analysis, the distribution of aerosols can be assessed. This paper describes the validation of a screening method for the assessment of aerosol distribution in workplaces. The method has been shown to have adequate performance for screening studies of deposited aerosols in workplaces and can, thus, be a useful complement to traditional occupational hygiene measurements. The applicability for screening measurements is demonstrated by assessment of the distribution of welding fumes in a welding workshop and of a cytotoxic drug in a drug preparation room at an oncology clinic. Being rapid and simple, it will be a useful tool to identify target spots for more extensive assessment of the workers exposure situation.
Spectroscopy of Naphthalene Diimides and Their Anion Radicals
Authors: Andric Goja , Boas John F. , Bond Alan M. , Fallon Gary D. , Ghiggino Kenneth P. , Hogan Conor F. , Hutchison James A. , Lee Marcia A.-P. , Langford Steven J. , Pilbrow John R. , Troup Gordon J. , Woodward Clint P.
Published: October 2004

Naphthalene diimides 1–4 having different N,N-disubstitution undergo single electron reduction processes either chemically or electrochemically to yield the corresponding radical anion in high yield. This study concentrates on 1, bearing pentyl side chains connected through the diimide nitrogens, and compares the results obtained against those bearing isopropyl, propargyl, and phenylalanyl side chains. Compound 1 exhibits mirror image absorption and fluorescence in the near-UV region in CH2Cl2 and dimethylformamide that is typical of monomeric N,N-dialkyl-substituted naphthalene diimides. In toluene, excimer-like emission is observed, which suggests ground-state complexes involving 1 are formed. X-Ray crystallography has been used to characterize 1 in the solid state. Cyclic voltammetry enables the reversible potentials for [NDI]0/– and [NDI]−/2– type processes to be measured. Bulk one-electron reduction of 1–4 is characterized by dramatic changes in the absorption and emission spectra. Additionally, highly structured EPR (electron paramagnetic resonance) signals from dimethylformamide solutions of the radical anions of 1–3 have been obtained and are consistent with coupling between the unpaired electron and the naphthalene diimide nitrogens and hydrogens and the NCH hydrogens of the appropriate side chains. The overall structure of the EPR spectrum is substituent-dependent. These changes in spectroscopic output upon an electronic input may be described as a simple ‘on/off’ switching mechanism with which to apply a ‘bottom-up’ approach to molecular device manufacture.
Copper Speciation in Glacial Stream Waters of Rutor Glacier (Aosta Valley, Italy)
Authors: Monticelli Damiano , van den Berg Constant M. G. , Pozzi Andrea , Dossi Carlo
Published: October 2004

The chemical speciation of copper in stream waters from Rutor Glacier was determined by cathodic stripping voltammetry with ligand competition against salicylaldoxime. The complexation of salicylaldoxime was calibrated at various calcium concentrations, the major competing cation in these waters. Copper concentrations (3–7 nM) were approximately ten-fold lower than typical for rain waters in this region, indicating that copper had been removed by adsorption onto rock and other particles. Strong copper binding ligands, with log K′CuL = 12.5–12.9, were detected in all samples, including waters emerging from beneath the glacier, with no detectable change in the ligand composition down stream. The results suggest that the ligands could originate from in situ production from algae in snow and ice, or directly from the precipitation.
Cross-scale interactions, nonlinearities, and forecasting catastrophic events
Authors: Peters Debra P. C. , Pielke Roger A. , Bestelmeyer Brandon T. , Allen Craig D. , Munson-McGee Stuart , Havstad Kris M.
Published: October 2004

Catastrophic events share characteristic nonlinear behaviors that are often generated by cross-scale interactions and feedbacks among system elements. These events result in surprises that cannot easily be predicted based on information obtained at a single scale. Progress on catastrophic events has focused on one of the following two areas: nonlinear dynamics through time without an explicit consideration of spatial connectivity [Holling, C. S. (1992)Ecol. Monogr.62, 447–502] or spatial connectivity and the spread of contagious processes without a consideration of cross-scale interactions and feedbacks [Zeng, N., Neeling, J. D., Lau, L. M. & Tucker, C. J. (1999)Science286, 1537–1540]. These approaches rarely have ventured beyond traditional disciplinary boundaries. We provide an interdisciplinary, conceptual, and general mathematical framework for understanding and forecasting nonlinear dynamics through time and across space. We illustrate the generality and usefulness of our approach by using new data and recasting published data from ecology (wildfires and desertification), epidemiology (infectious diseases), and engineering (structural failures). We show that decisions that minimize the likelihood of catastrophic events must be based on cross-scale interactions, and such decisions will often be counterintuitive. Given the continuing challenges associated with global change, approaches that cross disciplinary boundaries to include interactions and feedbacks at multiple scales are needed to increase our ability to predict catastrophic events and develop strategies for minimizing their occurrence and impacts. Our framework is an important step in developing predictive tools and designing experiments to examine cross-scale interactions.
Dimensional reduction for a Bayesian filter
Authors: Chorin Alexandre J. , Krause Paul
Published: October 2004

An adaptive strategy is proposed for reducing the number of unknowns in the calculation of a proposal distribution in a sequential Monte Carlo implementation of a Bayesian filter for nonlinear dynamics. The idea is to solve only in directions in which the dynamics is expanding, found adaptively; this strategy is suggested by earlier work on optimal prediction. The construction should be of value in data assimilation, for example, in geophysical fluid dynamics.
A mathematical model for the scaling of turbulence
Authors: Barenblatt Grigory Isaakovich , Chorin Alexandre J.
Published: October 2004

We present a simple physical model of turbulent wall-bounded shear flows that reveals exactly the scaling properties we had previously obtained by similarity considerations. The significance of our results for the understanding of turbulence is pointed out.
Experimental test of Hatano and Sasa's nonequilibrium steady-state equality
Authors: Trepagnier E. H. , Jarzynski C. , Ritort F. , Crooks G. E. , Bustamante C. J. , Liphardt J.
Published: October 2004

Most natural processes occur far from equilibrium and cannot be treated within the framework of classical thermodynamics. In 1998, Oono and Paniconi [Oono, Y. & Paniconi, M. (1998)
Prog. Theor. Phys. Suppl.
130, 29–44] proposed a general phenomenological framework, steady-state thermodynamics, encompassing nonequilibrium steady states and transitions between such states. In 2001, Hatano and Sasa [Hatano, T. & Sasa, S. (2001)
Phys. Rev. Lett.
86, 3463–3466] derived a testable prediction of this theory. Specifically, they were able to show that the exponential average of
Y
, a quantity similar to a dissipated work, should be equal to zero for arbitrary transitions between nonequilibrium steady states, –ln〈
e

–
Y

〉 = 0. We have tested this strong prediction by measuring the dissipation and fluctuations of microspheres optically driven through water. We have found that –ln〈
e

–
Y

〉 ≈ 0 for three different nonequilibrium systems, supporting Hatano and Sasa's proposed extension of thermodynamics to arbitrary steady states and irreversible transitions.
Ammonia-oxidizing bacteria respond to multifactorial global change
Authors: Horz Hans-Peter , Barbrook Adrian , Field Christopher B. , Bohannan Brendan J. M.
Published: October 2004

Recent studies have demonstrated that multiple co-occurring global changes can alter the abundance, diversity, and productivity of plant communities. Belowground processes, often mediated by soil microorganisms, are central to the response of these communities to global change. Very little is known, however, about the effects of multiple global changes on microbial communities. We examined the response of ammonia-oxidizing bacteria (AOB), microorganisms that mediate the transformation of ammonium into nitrite, to simultaneous increases in atmospheric CO
2
, precipitation, temperature, and nitrogen deposition, manipulated on the ecosystem level in a California grassland. Both the community structure and abundance of AOB responded to these simulated global changes. Increased nitrogen deposition significantly altered the structure of the ammonia-oxidizing community, consistently shifting the community toward dominance by bacteria most closely related to
Nitrosospira
sp. 2. This shift was most pronounced when temperature and precipitation were not increased. Total abundance of AOB significantly decreased in response to increased atmospheric CO
2
. This decrease was most pronounced when precipitation was also increased. Shifts in community composition were associated with increases in nitrification, but changes in abundance were not. These results demonstrate that microbial communities can be consistently altered by global changes and that these changes can have implications for ecosystem function.
Influence of Camembert consumption on the composition and metabolism of intestinal microbiota: a study in human microbiota-associated rats
Authors: Lay Christophe , Sutren Malène , Lepercq Pascale , Juste Catherine , Rigottier-Gois Lionel , Lhoste Evelyne , Lemée Riwanon , Ruyet Pascale Le , Doré Joël , Andrieux Claude
Published: October 2004

The objective of the present study was to evaluate the consequence of Camembert consumption on the composition and metabolism of human intestinal microbiota. Camembert cheese was compared with milk fermented by yoghurt starters andLactobacillus caseias a probiotic reference. The experimental model was the human microbiota-associated (HM) rat. HM rats were fed a basal diet (HMB group), a diet containing Camembert made from pasteurised milk (HMCp group) or a diet containing fermented milk (HMfm group). The level of micro-organisms from dairy products was measured in faeces using cultures on a specific medium and PCR–temporal temperature gradient gel electrophoresis. The metabolic characteristics of the caecal microbiota were also studied: SCFA, NH3, glycosidase and reductase activities, and bile acid degradations. The results showed that micro-organisms from cheese comprised 105–108bacteria/g faecal sample in the HMCp group.Lactobacillusspecies from fermented milk were detected in HMfm rats. Consumption of cheese and fermented milk led to similar changes in bacterial metabolism: a decrease in azoreductase activity and NH3concentration and an increase in mucolytic activities. However, specific changes were observed: in HMCp rats, the proportion of ursodeoxycholic resulting from chenodeoxycholic epimerisation was higher; in HMfm rats, α and β-galactosidases were higher than in other groups and both azoreductases and nitrate reductases were lower. The results show that, as for fermented milk, Camembert consumption did not greatly modify the microbiota profile or its major metabolic activities. Ingested micro-organisms were able to survive in part during intestinal transit. These dairy products exert a potentially beneficial influence on intestinal metabolism.
Meta-analysis of the health effects of using the glycaemic index in meal-planning
Authors: Opperman A. Maretha , Venter Christina S. , Oosthuizen Welma , Thompson Rachel L. , Vorster Hester H.
Published: October 2004

Diabetes mellitus and CVD are some of the leading causes of mortality and morbidity. Accumulating data indicate that a diet characterised by low-glycaemic index (GI) foods may improve the management of diabetes or lipid profiles. The objective of the present meta-analysis was to critically analyse the scientific evidence that low-GI diets have beneficial effects on carbohydrate and lipid metabolism compared with high-GI diets. We searched for randomised controlled trials with a crossover or parallel design published in English between 1981 and 2003, investigating the effect of low-GI v. high-GI diets on markers for carbohydrate and lipid metabolism. Unstandardised differences in mean values were examined using the random effects model. The main outcomes were fructosamine, glycated Hb (HbA1c), HDL-cholesterol, LDL-cholesterol, total cholesterol and triacylglycerol. Literature searches identified sixteen studies that met the strict inclusion criteria. Low-GI diets significantly reduced fructosamine by –0·1 (95 % CI –0·20, 0·00) mmol/l (P=0·05), HbA1c by 0·27 (95 % CI –0·5, –0·03) % (P=0·03), total cholesterol by –0·33 (95 % CI –0·47, –0·18) mmol/l (P>0·0001) and tended to reduce LDL-cholesterol in type 2 diabetic subjects by –0·15 (95 % CI –0·31, –0·00) mmol/l (P=0·06) compared with high-GI diets. No changes were observed in HDL-cholesterol and triacylglycerol concentrations. No substantial heterogeneity was detected, suggesting that the effects of low-GI diets in these studies were uniform. Results of the present meta-analysis support the use of the GI as a scientifically based tool to enable selection of carbohydrate-containing foods to reduce total cholesterol and to improve overall metabolic control of diabetes.
Addition of pearl barley to a rice-based diet for newly weaned piglets increases the viscosity of the intestinal contents, reduces starch digestibility and exacerbates post-weaning colibacillosis
Authors: Hopwood Deborah E. , Pethick David W. , Pluske John R. , Hampson David J.
Published: October 2004

The purposes of the present study were to investigate the effects of feeding a cereal grain containing NSP on body growth and the intestinal microenvironment of recently weaned pigs, and to examine resultant associations with pathogenicEscherichia coliin the intestinal tract. In Expt 1, pearl barley, a grain rich in soluble NSP, was incorporated (250, 500 or 750 g/kg diet) into a low-fibre control diet based on cooked white rice and fed for 7–10 d following weaning. Consumption of pearl barley did not significantly alter piglet live-weight gain compared with the control cooked rice diet, but it accelerated large intestinal growth and fermentation, decreased ileal starch digestibility and increased intestinal viscosity. Expt 2 was conducted to determine whether these differences would favour proliferation of enterotoxigenicE. coli, the bacterium causing post-weaning colibacillosis (PWC). Three groups of pigs were weaned onto diets based on cooked white rice, rice with 500 g pearl barley/kg, or rice with 500 g pearl barley/kg supplemented with exogenous enzymes (Porzyme(tm) 8100; Danisco, Marlborough, Wilts., UK). Pigs were inoculated orally with haemolyticE. coliserovar O8;K87;K88 after weaning. Animals eating the pearl barley had increased viscosity of the intestinal contents, greater intestinal colonisation with theE. colistrain and more diarrhoea than pigs fed the rice-only diet. The enzymes did not reduce viscosity or protect from PWC. The results suggest that pearl barley alters the intestinal microenvironment and predisposes to PWC, whilst a low-viscosity, highly digestible diet based on cooked white rice is protective.
The validation of using serum iron increase to measure iron absorption in human subjects
Authors: Hoppe Michael , Hulthén Lena , Hallberg Leif
Published: October 2004

The objectives of the present study were to study the correlation between the change in serum Fe and Fe absorption when administering 100 mg Fe (as FeSO4) orally, and to study the correlation between the absorption from a 3 mg and a 100 mg Fe (as FeSO4) dose. The study was conducted in a group of eleven male blood donors, without any evident infection, who had given blood 8 weeks before the study. On three consecutive mornings the subjects were served a wheat roll fortified with Fe. On the first 2 d the roll was fortified with 3 mg Fe labelled with59Fe; on day 3 the roll was fortified with 100 mg Fe labelled with55Fe. The serum Fe response to the 100 mg dose was followed for 6 h. Fe absorption was measured by whole-body counting. High correlations were seen between the absorption of Fe and the change in serum Fe after 100 mg Fe (r20·94,P>0·001), between the absorption from 3 mg and 100 mg Fe (r20·88,P>0·001), and between the absorption from 3 mg Fe and change in serum Fe after 100 mg Fe (r20·90,P>0·001). This strengthens the evidence that it is possible to use the change in serum Fe as a measure of Fe absorption, e.g. when establishing the relative bioavailability for Fe powders. The results also imply that the induced serum Fe increase following 100 mg Fe added to a food could predict the Fe absorption of a small dose of Fe added to the same meal.
Adherence to the Mediterranean dietary pattern among the population of the Balearic Islands
Authors: Tur Josep A. , Romaguera Dora , Pons Antoni
Published: October 2004

The aim of the present study was to assess the prevalence of the Mediterranean dietary pattern (MDP) in the population of the Balearic Islands and socio-demographic and lifestyle factors that might determine adherence to the MDP. A cross-sectional nutritional survey was carried out in the Balearic Islands between 1999 and 2000. A random sample (n 1200) of the adult population (16–65 years) was interviewed. Dietary questionnaires incorporating questions related to socio-economic status, education level, lifestyle factors and health status were utilised. Dietary habits were assessed by means of two 24 h recalls, and a quantitative food-frequency questionnaire. Adherence to the MDP was defined according to a score constructed considering the consumption of nine MDP characteristic components: high MUFA:saturated fatty acids ratio, moderate ethanol consumption, high legumes, cereals and roots, fruits, vegetables, and fish consumption, and low consumption of meat and milk. Then, socio-demographic, lifestyle and health status variables that could determine a higher or lower adherence were assessed. Adherence to the MDP among the population of the Balearic Islands was found to be 43·1 (sd 5·8) %, and was similar in all socio-demographic and lifestyle groups, with some differences according to age, sex and physical status. There was an increase in the percentage of adherence with age, which was greater in males than in females. A more physically active lifestyle was associated with a higher adherence to the MDP. The promotion of the Mediterranean lifestyle, including the MDP and greater physical activity, should be reinforced in the population of the Balearic Islands and especially in the younger generations.
Socio-economic and behavioural factors are predictors of food use in the National Food Stamp Program Survey
Authors: Bhargava Alok
Published: October 2004

The unhealthy dietary patterns in the USA especially among low-income households demand complex strategies for health promotion. The present paper analysed the proximate determinants of 7 d food use by 919 participants in the National Food Stamp Program Survey conducted in 1996. The households' consumption of dietary energy, carbohydrate, protein, fibre, saturated, monounsaturated and polyunsaturated fats, Ca, Fe, β-carotene and vitamin C were explained by background, socio-economic and behavioural factors. Certain methodological issues arising in modelling food use data were addressed. The results showed that the subjects' knowledge of the US Department of Agriculture food pyramid, reading nutrition labels, adopting a low-fat diet, selecting fruits and vegetables, saving money at grocery stores and frequency of shopping trips were often significantly associated (P>0·05) with the densities of nutrient use. The results identified certain aspects of nutrition education programmes that deserve greater emphasis for improving diet quality. The model for energy intake indicated that disbursing half the food stamp benefits on a 2-week basis and better shopping practices can enhance food availability.
Plasma folate as marker of folate status in epidemiological studies: the European Investigation into Cancer and Nutrition (EPIC)-Potsdam study
Authors: Drogan D. , Klipstein-Grobusch K. , Wans S. , Luley C. , Boeing H. , Dierkes J.
Published: October 2004

Folate deficiency is often discussed as a potential risk factor for CVD and some cancers. Reliable assessment of folate status in large-scale epidemiological studies is therefore of major importance. The present study assessed the value of plasma folate (PF) compared with erythrocyte folate (EF) as a marker of folate status in 363 participants in the European Investigation into Cancer and Nutrition (EPIC)-Potsdam cohort. EF and PF, total homocysteine (tHcy), pyridoxine, cobalamin, creatinine, total protein and packed cell volume were determined; glutamate carboxypeptidase (GCP) C1561T, reduced folate carrier (RFC) G80A and methylenetetrahydrofolate (MTHFR) C677T polymorphisms were analysed. Anthropometric measurements were taken and dietary intake was assessed with the EPIC-Potsdam food-frequency questionnaire. Comparison of EF and PF with factors that may modulate their concentrations was performed. Cross-classification of blood folates in quintile categories resulted in correct classification into the same or adjacent category of 75·5 % of all subjects. Age, BMI, pyridoxine and cobalamin, fruit and vegetable intake, and vitamin supplementation 24 h before blood draw were positively associated with EF and with PF. For tHcy an inverse association was found. Participants with the MTHFR 677TT genotype showed significantly elevated EF concentrations compared with those with 677CT genotype; EF and PF were more strongly correlated (r0·78,P>0·0001) for participants with MTHFR 677TT genotype than for those with the 677CC or 677CT genotype. In summary, our present results indicate that plasma folate seems to be a suitable marker for assessment of folate status for use in large-scale epidemiological studies.