bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of the international system of units (SI) in isotope ratio mass spectrometry
Authors: Milton Martin J. T. , Wielgosz Robert I. 
Published: November 2002

AbstractIn this communication, we show how the established principles of the International System of Units (SI) can be used to develop a basis for stable, comparable and coherent measurements of isotope ratios by mass spectrometry. We show that there are no important differences in the traceability of quantities that represent ratios of the abundance of isotopes and those that represent fractions. However, it is important to distinguish between results expressed in ‘absolute’ terms and those expressed relative to stated references such as those expressed in terms of the commonly used quantity ‘delta’. © Crown copyright 2002. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.
Making an honest measurement scale out of the oxygen isotope δ‐values
Authors: Gat Joel R. , DeBievre Paul 
Published: November 2002

AbstractThe differential measurement of the abundance of oxygen isotopes based on reference materials, such as VSMOW for the case of water, was used because the precision of the absolute mass‐spectrometric determination of the abundance fell short of the differences to be measured. Since then these measurements have been much improved, so that a calibration scheme of the oxygen isotope abundance in water, carbonates, silica, phosphates, sulfates, nitrates and organic materials is suggested, based on an accredited primary standard of oxygen in air and using standard fluorination and O2 to CO2 conversion techniques. Copyright © 2002 John Wiley & Sons, Ltd.
Rhetoric and reality in the allocation of water to the environment: a case study of the Goulburn River, Victoria, Australia
Authors: Ladson Anthony , Finlayson Brian 
Published: November 2002

AbstractIn the Goulburn River, located in Victoria (Australia), dams and diversions for irrigation have modified streamflows and water temperature, and contributed to environmental degradation that includes declining native fish populations.With the passage of a new Water Act in 1989, the Victorian Government proposed to address environmental and water allocation issues through the development of tradeable water entitlements. Initially, these had a strong environmental focus and were to be allocated within an adaptive management framework that involved monitoring and evaluation to refine the total allowable diversion to sustainable levels. The actual specification of tradeable water entitlements for the Goulburn River, undertaken in 1995, differed substantially from those early proposals. Entitlements were largely based on historical use with limited and ineffective allocation of water to the environment because water temperature was not considered. A water market has been established but market failure is likely to result in an under‐allocation of water to the environment. Access to the market is restricted except to irrigation authorities and water users, and transaction costs and uncertainties in environmental requirements reinforce the status quo in water allocation which is dominated by production values. Copyright © 2002 John Wiley & Sons, Ltd.
Brillouin backscattering instability in inhomogeneous
collisional plasma
Authors: SHALABI BASSAM , AL-KHATEEB AHMED 
Published: November 2002

Brillouin backscattering instability is investigated in
inhomogeneous collisional plasma. The slow-coupling equations
for the instability in a medium with linear density ramp are
obtained. For large inhomogeneity scale length, the homogeneous
growth rate is found to be modified by a factor of[1/square root(2) times square root(ω02/
(ω02 + νe2) +
ω0/square root(ω02 +
νe2))]For the convective instability, the amplification factor is found to
be[Λ = (|γB0|2/2β)(ω02/ω02 + νe2)]The presence of collisions leads to a reduction in both the growth
rate and the amplification factor, where the threshold intensity for the
instability to occur increases.
ON THE STRUCTURE OF THE SPACE OF GEOMETRIC PRODUCT-FORM MODELS
Authors: Bayer Nimrod , Boucherie Richard J. 
Published: November 2002

This article deals with Markovian models defined on a
finite-dimensional discrete state space and possess a stationary
state distribution of a product-form. We view the space of such
models as a mathematical object and explore its structure.
We focus on models on an orthant
[script Z]+n, which are homogeneous within
subsets of [script Z]+n called walls, and
permit only state transitions whose ∥ ∥∞-length
is 1. The main finding is that the space of such models exhibits a
decoupling principle: In order to produce a given product-form
distribution, the transition rates on distinct walls of the same
dimension can be selected without mutual interference. This principle
holds also for state spaces with multiple corners (e.g., bounded boxes in
[script Z]+n).In addition, we consider models which are homogeneous throughout
a finite-dimensional grid [script Z]n, now without
a fixed restriction on the length of the transitions. We characterize
the collection of product-form measures which are invariant for a model
of this kind. For such models with bounded transitions, we prove, using
Choquet's theorem, that the only possible invariant measures are
product-form measures and their combinations.
A Comparison of Modern Hyperbolic Methods for Semiconductor Device Simulation: NTK Central Scheme Vs. CLAWPACK
Authors: Gardner Carl L. , Gelb Anne , Hernandez Justin 
Published: November 2002

Two modern hyperbolic methods—a second‐order Godunov method in the software package CLAWPACK and the second‐order Nessyahu–Tadmor–Kurganov (NTK) central scheme—are compared for simulating an electron shock wave in the classical hydrodynamic model for semiconductor devices.The NTK central scheme, which does not employ Riemann problem solutions, is described in detail. Special attention is paid in both methods to handling the source terms in the hydrodynamic model. CLAWPACK incorporates the source terms by a splitting method, while our version of the NTK scheme is unsplit.
Fresh Water Fish Habitat Science and Management in India
Authors: Ghosh S. K. , Ponniah A. G. 
Published: November 2002

Abstract
India is a land of diverse topography, climate and natural resource. There are 12 major rivers and 48 lesser rivers with a total catchment area of 277.6 million hectares. The fresh water resources of the country which are varied harbor 587 species of finfish and account for 9.3 percent of global inland fish production. India's natural capital of fish habitat resource has been eroded as reflected in loss of bio-diversity and reduced fish landings. Studies on the ecology, environment and fisheries of five major river systems in addition to reservoirs and flood plain lake fisheries have been conducted with greater focus on water quality and less on physical habitat parameters.
The Central Water Commission is responsible for development of all freshwater bodies whereas, the National River Conservation Directorate is responsible for river conservation. River conservation programs cover major rivers in 10 States of the country, the ‘Ganga Action Plan’ being the most important. These projects target improvement in water quality and not fish habitat improvement. Lack of concern for fish habitat is reflected in the planning of Farakka barrage on the river Ganga (The Ganges) and its impact on ‘Hilsa’ run. Environmental laws have not achieved desired objectives for lack of enforcement mechanisms. Fishery scientists and resource users are not involved in the river conservation program.
The fresh water habitat management situation in India evokes both concern and hope. Concern arises out of the missing elements in the existing fish habitat research, planning and management of resource. The hope for the future is our increasing awareness of the need for better resource management and environmental conservation. India has a responsibility to conserve these natural assets for future generations. Potential steps are outlined.
Fish Habitat Science and Management in Finnish Freshwaters
Authors: Jurvelius Juha , Auvinen Heikki 
Published: November 2002

Abstract
The area of Finnish inland waters is 33,500 km2. Forty fish species, eleven of them indigenous, have been encountered in the area. The annual catch from inland fisheries is around 40,000 metric tons. The largest changes in fish habitats in Finnish inland waters have been caused by hydropower construction and timber-floating in rivers, and eutrophication and water level regulation in lakes. River-spawning fish species have lost their spawning habitats or access to spawning sites. In many lakes, eutrophication together with selective gill-net fishing has shifted the fish assemblages towards dominance by cyprinids and other small-sized plankton feeders. Acid precipitation has affected fish stocks in ca. 1% of the 56,000 lakes. Acidification has decreased during the past decade. The management and use of water resources is regulated by the Water Act. To meet the requirements of the Act, e.g., in water construction works the use of the best available techniques (BAT) is required. Enhancement of fish habitats and natural reproduction is gaining importance in fisheries management instead of or together with stocking of young fish. Timber-floating has ceased in streams and rivers, and rehabilitation programs for fishery purposes have been carried out. Habitat-hydraulic models have been used to guide rehabilitation programs in rivers to meet the needs of juvenile salmonids. In lakes, eutrophication from point sources have been reduced. Reduction of non-point loads is now in the focus. Modelling of interactions in fish community, fishing and stocking has given promising results in fisheries management. Water level regulation practices that take into account the survival of fish eggs and larvae are considered in large reservoirs and lakes. In the future, the dynamics of ecosystems should be given more emphasis to mitigate the combined effects of anthropogenic influences on fish habitats and communities.
Science for freshwater fish habitat management in Canada: Current status and future prospects
Authors: Minns Charles K. 
Published: November 2002

Abstract
Canada's diverse freshwaters support a rich biodiversity of more than 200 species. Canada has strong legislation capable of conserving and protecting freshwaters habitats. Fish are a key driver and indicator for restoration and conservation efforts. Many of Canada's freshwater species in Canada are thought to be at risk.
Apart species such as brook trout, lake trout, walleye, and yellow perch, the ecology and habitat requirements of most freshwater species are poorly known. Studies have mainly been descriptive and comparative but experimental, ecosystem-scale integration, and modelling activities are increasing. While science related to fish and their habitats is growing, little is focused on the links between the production and dynamics of fish populations and communities, and the supply and distribution of habitats at various scales.
Habitat management is still mainly reactive, assessing development at the site-level with considerable uncertainty about the mitigation and compensation actions approved to offset habitat losses and modifications. Communication between science and management is improving. Canada has invested much energy on cumulative impact assessment but effective methods for tracking cumulative change and the interaction of multiple stresses have not emerged. Nonetheless there is a broad consensus on the need to take an ecosystem-based approach to sustainable use of Canada's natural renewable resources, including freshwaters and their fish. Management needs to shift to a more proactive approach supported by better deployment of available science and scientific methods. Science should emphasize quantitative whole ecosystem studies of fish and habitat especially the development of models and experimental manipulations.
If current trends of fish habitat loss are maintained in Canada, further declines in the quality and diversity of freshwater fish resources are certain despite our apparent natural wealth. Modest investments in securing the future of its freshwater fishery resources based on scientific advice may yet begin movement toward an ecologically sustainable future.
Spatial Characterization of Water Quality in Seven Eastern Kentucky Reservoirs Using Multivariate Analyses
Authors: Davis Stephen E. , Reeder Brian C. 
Published: November 2002

Abstract
We conducted water quality surveys along seven eastern Kentucky reservoirs three times during the 1994 growing season in order to understand the spatial variability within and between impoundments from a common geological setting. Sixteen parameters were measured at sites along the reservoirs representing each zone (riverine, transition, or lacustrine), and eight of these parameters displayed a statistically significant site/zone effect. Most of these were particle-associated parameters (total Fe, NH4+, total suspended solids, and total phosphorus) that decreased significantly down-reservoir. Water transparency increased significantly down-reservoir, in accordance with this pattern. Temperature and dissolved oxygen also showed a significant spatial effect, as temperature was highest towards the riverine end and dissolved oxygen was highest at the lacustrine end. Six parameters showed significant variability among these reservoirs, including ammonium and chlorophyll a. The remaining four (conductivity, sulfate, alkalinity and pH) displayed similar patterns across reservoirs apparently as a result of local geologic attributes. Another goal of this work was to use a multivariate statistical approach to aid in understanding the relationships between water quality parameters in this region and to group zones within a reservoir according to their similarities in water quality. Principal Components Analysis reduced sixteen parameters to five principal components that accounted for 74 percent of the total variability in water quality. Two of these principal components contained all of the particle-associated and local-geologic parameters, and accounted for 42% of the total variability. Cluster analyses showed that the water quality signatures of two reservoirs were quite different from the rest. Interestingly, these represented the most pristine and most disturbed watersheds of all seven systems. Our findings are relevant to the management of these and other similar reservoir systems.
Organochlorine contamination in the fish of the River Ganges, India
Authors: Kumari Anupma , Sinha R. K. , Gopal Krishna 
Published: November 2002

Abstract
Concentrations of persistent organochlorine residues were measured in economically important fish of the River Ganges from different locations in Bihar. The contamination pattern of organochlorines in fishes from several locations was Dichlorodiphenyltrichloroethanes (DDTs) &gt;Hexachlorocyclohexanes (HCHs) &gt;aldrin&gt;endosulfan. The average wet weight concentrations in the muscles of fishes was; DDTs, 13.6 to 1665.9 ng g-1; HCHs, 115.8 to 1206.8 ng g-1; aldrin, 3.1 to 86.1 ng g-1; and endosulfan 2.9 to 74.5 ng g-1. The study indicates that organochlorine contaminants are still entering the Ganges river system, and suggests that the human population that consumes contaminated fish from the river may be at risk from those contaminants.
Partly folded states of members of the lysozyme/lactalbumin superfamily: A comparative study by circular dichroism spectroscopy and limited proteolysis
Authors: Polverino de Laureto Patrizia , Frare Erica , Gottardo Rossella , van Dael Herman , Fontana Angelo 
Published: November 2002

AbstractThe partly folded states of protein members of the lysozyme (LYS)/α‐lactalbumin (LA) superfamily have been analyzed by circular dichroism (CD) measurements and limited proteolysis experiments. Hen, horse, dog, and pigeon LYSs and bovine LA were used in the present study. These are related proteins of 123‐ to 129‐amino‐acid residues with similar three‐dimensional structures but low similarity in amino acid sequences. Moreover, notable differences among them reside in their calcium‐binding properties and capability to adopt partly folded states or molten globules in acid solution (A‐state) or on depletion of calcium at neutral pH (apo‐state). Far‐ and near‐UV CD measurements revealed that although the structures of hen and dog LYS are rather stable in acid at pH 2.0 or at neutral pH in the absence of calcium, conformational transitions to various extents occur with all other LYS/LA proteins herewith investigated. The most significant perturbation of tertiary structure in acid was observed with bovine LA and LYS from horse milk and pigeon egg‐white. Pepsin and proteinase K were used as proteolytic probes, because these proteases show broad substrate specificity, and therefore, their sites of proteolysis are dictated not by the specific amino acid sequence of the protein substrate but by its overall structure and dynamics. Although hen LYS at pH 2.0 was fully resistant to proteolysis by pepsin, the other members of the LYS/LA superfamily were cleaved at different rates at few sites of the polypeptide chain and thus producing rather large protein fragments. The apo‐form of bovine LA, horse LYS, and pigeon LYS were attacked by proteinase K at pH 8.3, whereas dog and hen LYSs were resistant to proteolysis when reacted under identical experimental conditions. Briefly, it has been found that the proteolysis data correlate well with the extent of conformational transitions inferred from CD spectra and with existing structural informations regarding the proteins herewith investigated, mainly derived from NMR and hydrogen exchange measurements. The sites of initial proteolytic cleavages in the LYS variants occur at the level of the β‐subdomain (approximately chain region 34–57), in analogy to those observed with bovine LA. Proteolysis data are in agreement with the current view that the molten globule of the LYS/LA proteins is characterized by a structured α‐domain and a largely disrupted β‐subdomain. Our results underscore the utility of the limited proteolysis approach for analyzing structure and dynamics of proteins, even if adopting an ensemble of dynamic states as in the molten globule.
The interaction of β2‐glycoprotein I domain V with chaperonin GroEL: The similarity with the domain V and membrane interaction
Authors: Gozu Masayo , Hoshino Masaru , Higurashi Takashi , Kato Hisao , Goto Yuji 
Published: November 2002

AbstractTo clarify the mechanism of interaction between chaperonin GroEL and substrate proteins, we studied the conformational changes; of the fifth domain of human β2‐glycoprotein I upon binding to GroEL. The fifth domain has a large flexible loop, containing several hydrophobic residues surrounded by positively charged residues, which has been proposed to be responsible for the binding of β2‐glycoprotein I to negatively charged phospholipid membranes. The reduction by dithiothreitol of the three intramolecular disulfide bonds of the fifth domain was accelerated in the presence of stoichiometric amounts of GroEL, indicating that the fifth domain was destabilized upon interaction with GroEL. To clarify the GroEL‐induced destabilization at the atomic level, we performed H/2H exchange of amide protons using heteronuclear NMR spectroscopy. The presence of GroEL promoted the H/2H exchange of most of the protected amide protons, suggesting that, although the flexible loop of the fifth domain is likely to be responsible for the initiation of binding to GroEL, the interaction with GroEL destabilizes the overall conformation of the fifth domain.
Crystal structures and increased stabilization of the protein G variants with switched folding pathways NuG1 and NuG2
Authors: Nauli Sehat , Kuhlman Brian , Le Trong Isolde , Stenkamp Ronald E. , Teller David , Baker David 
Published: November 2002

AbstractWe recently described two protein G variants (NuG1 and NuG2) with redesigned first hairpins that were almost twice as stable, folded 100‐fold faster, and had a switched folding mechanism relative to the wild‐type protein. To test the structural accuracy of our design algorithm and to provide insights to the dramatic changes in the kinetics and thermodynamics of folding, we have now determined the crystal structures of NuG1 and NuG2 to 1.8 Å and 1.85 Å, respectively. We find that they adopt hairpin structures that are closer to the computational models than to wild‐type protein G; the RMSD of the NuG1 hairpin to the design model and the wild‐type structure are 1.7 Å and 5.1 Å, respectively. The crystallographic B factor in the redesigned first hairpin of NuG1 is systematically higher than the second hairpin, suggesting that the redesigned region is somewhat less rigid. A second round of structure‐based design yielded new variants of NuG1 and NuG2, which are further stabilized by 0.5 kcal/mole and 0.9 kcal/mole.
Metal ions and phosphate binding in the H‐N‐H motif: Crystal structures of the nuclease domain of ColE7/Im7 in complex with a phosphate ion and different divalent metal ions
Authors: Sui Meng‐Jiun , Tsai Li‐Chu , Hsia Kuo‐Chiang , Doudeva Lyudmila G. , Ku Wen‐Yen , Han Gye Won , Yuan Hanna S. 
Published: November 2002

AbstractH‐N‐H is a motif found in the nuclease domain of a subfamily of bacteria toxins, including colicin E7, that are capable of cleaving DNA nonspecifically. This H‐N‐H motif has also been identified in a subfamily of homing endonucleases, which cleave DNA site specifically. To better understand the role of metal ions in the H‐N‐H motif during DNA hydrolysis, we crystallized the nuclease domain of colicin E7 (nuclease‐ColE7) in complex with its inhibitor Im7 in two different crystal forms, and we resolved the structures of EDTA‐treated, Zn2+‐bound and Mn2+‐bound complexes in the presence of phosphate ions at resolutions of 2.6 Å to 2.0 Å. This study offers the first determination of the structure of a metal‐free and substrate‐free enzyme in the H‐N‐H family. The H‐N‐H motif contains two antiparallel β‐strands linked to a C‐terminal α‐helix, with a divalent metal ion located in the center. Here we show that the metal‐binding sites in the center of the H‐N‐H motif, for the EDTA‐treated and Mg2+‐soaked complex crystals, were occupied by water molecules, indicating that an alkaline earth metal ion does not reside in the same position as a transition metal ion in the H‐N‐H motif. However, a Zn2+ or Mn2+ ions were observed in the center of the H‐N‐H motif in cases of Zn2+ or Mn2+‐soaked crystals, as confirmed in anomalous difference maps. A phosphate ion was found to bridge between the divalent transition metal ion and His545. Based on these structures and structural comparisons with other nucleases, we suggest a functional role for the divalent transition metal ion in the H‐N‐H motif in stabilizing the phosphoanion in the transition state during hydrolysis.