bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of intermolecular disulfide linkages in underivatised peptides using negative ion electrospray mass spectrometry. A joint experimental and theoretical study
Authors: Bilusich Daniel , Bowie John H.
Published: February 2007

The [MH]− ion of a symmetrical peptide containing one intermolecular disulfide linkage cleaves through the disulfide link to produce up to four fragment anions. Two of these characteristic fragments are formed by a cleavage initiated from the Cys enolate anion on the peptide backbone. The other fragment anions are formed by a cleavage directed from an anion site on the disulfide side chain. In the case of an unsymmetrical peptide containing one intermolecular disulfide, the [MH]− anion may cleave through the disulfide unit to give a maximum of eight cleavage anions. These fragmentations are low‐energy processes as determined by theoretical calculations carried out at the HF/6‐31G(d)//AM1 level of theory. Collision‐induced mass spectra of the fragment anions may provide the sequence of the peptide. Copyright © 2007 John Wiley & Sons, Ltd.
Does the electron ionization induced fragmentation of partly saturated stereoisomeric pyrrolo‐ and isoindoloquinazolinones show stereospecificity?
Authors: Pihlaja Kalevi , Martiskainen Olli , Stájer Géza
Published: February 2007

The electron ionization mass spectrometric behavior of pyrroloquinazolinones (1–6) and isoindoloquinazolinones (7–14) was studied. These compounds were further classified as partly saturated pyrroloquinazolinones (1–3), benzologues (7–11), methylene‐bridged derivatives (4–6, 12, 13) and a bisacyl compound (14). The mass spectra of the pyrrolo‐ and isoindoloquinazolinones did not exhibit stereospecific retro‐Diels‐Alder (RDA) fragmentations. The cyclohexane‐fused compounds 7 (cis annelated) and 8 (trans annelated) did display some other ions differing in their abundances that could be used to differentiate this pair of stereoisomers. Also the cyclohexene‐fused compounds 2, 3, 9 and 10 exhibited somewhat different ion abundances pairwise that could be utilized for isomeric differentiation. Earlier hypothesis of pyrrolo ring cleavage via the loss of C3H5O. was strengthened by the fragmentation of compounds 1–4. RDA(±H) fragmentation is more favorable than the formation of [M–R]+ ions (RH, C6H4CH3, or C6H4Cl) when an unsaturated bicyclic group is present but both RDA fragmentation and [M–R]+ formation occur for cyclohexene‐fused compounds, possibly because of the lower ring strain than with norbornene‐fused compounds. The [M–H]+ ion was abundant for compounds 7 and 8 as was [M–Ar]+ for 1–4 and 11. Although the compounds studied might participate in amide‐imidol tautomerism, no indication of such tautomerism was detected. Copyright © 2007 John Wiley & Sons, Ltd.
Rapid determination of six metabolites from multiple cytochrome P450 probe substrates in human liver microsome by liquid chromatography/mass spectrometry: application to high‐throughput inhibition screening of terpenoids
Authors: He Fan , Bi Hui‐chang , Xie Zhi‐yong , Zuo Zhong , Li Jian‐kang , Li Xin , Zhao Li‐zi , Chen Xiao , Huang Min
Published: February 2007

A rapid liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed for the determination of six cytochrome P450 (CYP) probe substrate metabolites including paracetamol (PAR) for CYP1A2, 4‐hydroxytolbutamide (OHTOL) for CYP2C9, 5‐hydroxyomeprazole (OHOMe) for CYP2C19, dextrorphan (DEXM) for CYP2D6, 6‐hydroxychlorzoxazone (OHCHL) for CYP2E1 and dehydronifedipine (DNIF) for CYP3A4. The triple‐quadrupole mass spectrometer was operated in both positive and negative modes, and selective reaction monitoring was used for quantification. The method was validated over the concentration ranges (0.075/0.04/0.05/0.02/0.1/0.0625 µM to 4.8/2.56/3.2/1.28/6.4/4.0 µM) for PAR/OHTOL/OHOME/DEXP/OHCHL/DNIF analytes with acceptable accuracy and precision. The inhibitory effect on the six CYP enzymes has been verified with their known specific inhibitors. This high‐throughput inhibition screening approach has been successfully applied to study the inhibitory effects of 18 terpenoids on CYP enzymes. Among them, tanshinone IIA and cryptotanshinone are found to be potent inhibitors to CYP1A2, while artemisinin is a marginal inhibitor to CYP1A2 and glycyrrhetic acid is a weak inhibitor to CYP2C9. Copyright © 2007 John Wiley & Sons, Ltd.
Size matters! Fragmentation chemistry of [Cu(L)n]2+ complexes of diacylglycerophosphocholines as a function of coordination number (n = 2–7)
Authors: James Patrick F. , Perugini Matthew A. , O'Hair Richard A. J.
Published: February 2007

[Cu(L)n]2+ complexes of 1,2‐dihexanoyl‐sn‐glycero‐3‐phosphocholine (L = D6PC) are formed upon electrospray ionization mass spectrometry (ESI‐MS) of an 8 mM solution of D6PC with 4 mM CuCl2 in 10 mM ammonium acetate buffer, pH 6.1. The collision‐induced dissociation (CID) reactions of the [Cu(L)n]2+ complexes were examined in a linear ion trap mass spectrometer. A rich fragmentation chemistry was observed, including: loss of a neutral ligand; intermolecular ligand‐ligand SN2 methylation; metal ion induced ligand fragmentation via carboxylate abstraction; and phosphate abstraction. The dominant reaction channel depends on the size (n) of the complex. Thus loss of neutral ligand(s) is the sole reaction channel for n = 5–7. At n = 4, SN2 methylation and carboxylate abstraction start to compete with neutral ligand loss. At n = 2 the carboxylate abstraction and phosphate abstraction reactions dominate the CID spectrum. The carboxylate abstraction and phosphate abstraction reactions are likely to be driven via neighboring group pathways. PM3 calculations, carried out to compare competing neighboring pathways based on the relative stabilities of the product ions, suggest a preference for five‐membered ring formation for ligand fragmentation involving both carboxylate and phosphate abstraction. Copyright © 2007 John Wiley & Sons, Ltd.
Characterization of polyether mixtures using thin‐layer chromatography and matrix‐assisted laser desorption/ionization mass spectrometry
Authors: Watanabe Takehiro , Kawasaki Hideya , Kimoto Takashi , Arakawa Ryuichi
Published: February 2007

Thin‐layer chromatography (TLC) and matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) were combined to achieve characterization of polyether mixtures. Three polyethers, polyethylene glycol (PEG), polypropylene glycol (PPG) and polytetramethylene glycol (PTMG), or mixtures of these compounds, were studied. One shortcoming of mixture analysis of synthetic polymers using MALDI‐MS is that individual polymers in the mixture may display different detection sensitivities. For example, the MALDI mass spectrum of an equimolar mixture of PEG, PPG and PTMG displayed a high intensity of PPG ions, while no PTMG ions were detectable; however, PTMG ions were detected after the mixture had been separated by TLC. This combined TLC and MALDI‐MS analysis of a PPG polymer bearing reactive epoxy groups showed that the polymer contained byproducts with different end‐groups. These byproducts were identified as chloro‐substituted polymers formed during polymer synthesis. Our study shows TLC to be a rapid and low‐cost separation technique, and that it can be combined with MALDI‐MS to achieve effective analysis of synthetic polymers. Copyright © 2007 John Wiley & Sons, Ltd.
Developing technology for surgery in the UK: a multidisciplinary meeting of engineers and surgeons
Authors: Taylor G. W.
Published: February 2007

There is an increasing necessity for surgeons and engineers to work together in order to target future technological developments at clinical need and cost‐effectiveness. This is a report of two linked meetings with these objectives, held at the Institute of Mechanical Engineers, London, UK. The two meetings were organized by the same faculty members and held on consecutive days. Delegates included surgeons, academic mechanical engineers, researchers and industrial representatives. The programme was made up of varied presentations by surgeons and engineers as well as open discussion of the topics covered. Delegates were updated on the current state of surgical robotics in the UK in four surgical specialties; urology, neurosurgery, orthopaedics and ENT. This included clinical and experimental evidence, together with discussion of future advances. Minimally invasive surgery, real‐time imaging and the development of more compact and cost effective surgical robots were identified as key areas for future research. Copyright © 2007 John Wiley & Sons, Ltd.
Modes of colonization of an heterogenous alluvial area on the edge of the garonne river by Phalaris arundinacea L
Authors: Conchou O. , Pautou G.
Published: February 2007

The modes of colonization of a heterogenous alluvial area by Phalaris arundinacea L., a pioneer species, were studied on the edge of the Garonne river downstream of Toulouse (S.W. France). The heterogeneity of the location is essentially represented (1) by the type of soil: sands and gravels on the banks of the Garonne and silts in the hollows at a certain distance from the river; (2) by the period of submersion: zones flooded only during short periods and zones submerged during six months of the year; and (3) by the fertility of the substratum.

The response of the Phalaris arundinacea population were measured using vegetation structure parameters and descriptions of the development cycle. Water plays the most important part in the identification of space colonization modes. Two types of individual plants appear. Those living in submerged environments for a very short time are characterized by both a high biomass and sexual reproduction energy allowance, and by unimodal growth. Those living in environments flooded over long periods are characterized by both a low biomass and sexual reproduction energy allowance, and by a bimodal growth in two successive generations: a submersion generation and a low‐water generation. Specific competition reduces the differences between the two types of individual plants from the point of view of population cover and of the structure and density of the individual plants. Phalaris arundinacea L. is shown to have a remarkable capacity for colonizing sites with distinctive ecological characteristics.
Effect of a changed temperature regime on the benthos of a norwegian regulated river
Authors: Saltveit Svein Jakob , Bremnes Trond , Brittain John E.
Published: February 2007

The lowermost 20 km of the River Surna, north‐western Norway receives cool water during summer from a hypolimnetic release mountain reservoir. The benthic fauna is completely dominated by insects. Benthic densities immediately below the power station are much lower than at all other localities. Although benthic densities increase downstream of the power station, they never exceed the densities above. The dominant insect group, chironomids, can be divided into four categories according to their abundance and distribution above and below the power station: (1) rare or absent above, but common or abundant below; (2) abundant or common above but rare or absent below; (3) slightly less abundant below; (4) unchanged abundance. No major differences in the species composition were recorded for stonefilies, mayflies and caddisflies.
Effects of dams, regulation and pollution on fish stocks in the Vltava river in Prague
Authors: Kubečka Jan , Vostradovský Jiři
Published: February 2007

Fish abundance and size composition in a 28 km stretch of the Vltava River in the Czech capital of Prague were studied using horizontal dual‐beam scientific sonar. Very low fish densities (0.6–0.7 fish/100m3) were found above Prague where the river is influenced by a cascade of reservoirs. These have a retention time of more than 100 days and release hypolimnetic water. A significant increase in fish density was found in the Berounka River confluence (a tributary with a normal, seasonal temperature pattern) just above the city (about 10 fish/100 m3). The fish stock is fairly low in the city itself because of channelization of the river bed (1.3–3.5 fish/100 m3), but much greater densities (14.9–16.9 fish/100 m3) were found below the city where the river receives a high organic load of partially treated sewage and has a semi‐natural shoreline. The largest average fish size and biomass were also reported from this section.
Effects of hydropower peaking on epilithon and invertebrate community trophic structure
Authors: Valentin S. , Wasson J. G. , Philippe M.
Published: February 2007

Hydropower generation induces rapid and frequent fluctuations of hydrodynamic parameters in rivers downstream of hydroelectric impoundments. On the FontauliéGre river (ArdéGche basin, France), water releases come from the Loire basin and the flow varies from 1.3 to 20 m3/s for one reach and from 0.1 to 20 m3/s for another reach. A reference site upstream was chosen to compare the communities with two downstream impacted sites. These two sites enabled two different base flow situations to be studied simultaneously and also the effect of base flow enhancement at one site. Benthic and epilithic samples were collected at the three sites on three dates. Epilithon development was linked to hydraulic regimes, with a major increase in algal biomass, dominated by filamentous algae, linked to the minimum base flow level and to the duration of periods without peaks. The macroinvertebrate communities of impacted reaches were less diversified and more specialized, with predominance of one or two taxa, whereas communities in upstream reaches were more diverse. The different morphological units specificity was attenuated in hydropeaking situations. In the case of a very low base flow, the lentic units with very low velocities (less than 4 cm s−1) had different fauna. The downstream algal development explained part of the change in benthic community structure in trophic groups (i.e. dominance of scrapers) in the site with the higher base flow. When the base flow was too low, a trophic discordance was observed and excess algal biomass represented a limiting factor. Thus, this study indicated that base flow level and duration had important effects on epilithic development and on invertebrate trophic structure in terms of mean velocities and of number of days without peaks.
Dispersal, growth and mortality of brown trout (Salmo trutta L.) stocked in a regulated West Norwegian river
Authors: Fjellheim Arne , Raddum Gunnar G. , Barlaup Bjosrn T.
Published: February 2007

As part of a fishery enhancement scheme, 70 000 fingerlings of anadromous brown trout (Salmo trutta L.) were stocked in the regulated River Teigdal, western Norway. To evaluate the stocking programme 10 000 of the hatchery reared fish were marked and released at 10 different localities. The results showed that the hatchery reared fish were inferior to wild brown trout. During the first weeks densities were high in the areas of stocking, varying between 27 and 680 individuals per m2. Stocked fish colonizing adjacent areas were mostly found upstream. Very few fish were found to cross the river from the point of release. One week after stocking food consumption of the hatchery reared fish was low compared with wild trout. Stocked trout had a lower growth rate (0.05 mm d−1) than native fish (0.08 mm d−1). However, fish stocked in deeper, slower flowing areas grew faster than those stocked in shallow riffle areas. The mortality of the stocked trout was 99% from July to April, being highest during the winter. Wild fish survived better, having a mortality of 79% over the same period. The value of the stocking programme is questioned. As an alterative, methods of biotope adjustment are proposed to increase the carrying capacity of wild trout in the river.
Macrozoobenthos in some rapids in a lowland river in Finland before and after the construction of a hydroelectric power plant
Authors: Nyman Curt
Published: February 2007

In the beginning of the 1980s a hydroelectric power plant was constructed in the middle course of the lowland river Perhonjoki in western Finland. Some shallow lakes upstream of the power plant were enlarged for use as a reservoir and some rapids downstream were dredged and remodelled. As a consequence of the construction, the flow was almost completely diverted from a 2.5 km stretch of the river and the former rapids in this area were remodelled with weirs. The discharge from the power plant was regulated in the short term during low flow seasons in winter and summer. The effects of this project on the stream bottom fauna has been studied. The sampling started in 1980 before any major impact took place and has continued until 1992.

In the low flow stretch of the river the lotic fauna of the former rapids has withdrawn to small rivulets and several species have disappeared, including the large caddisfly Arctopsyche ladogensis. In the remodelled rapids downstream from the power plant large numbers of black fly larvae have appeared every spring since the power plant was completed. The reason for this was probably dredging of the rapids, which wiped out the natural moss vegetation on the stones in the rapids and generated large areas of bare stone surfaces in places with suitable current velocities for the larvae. A lake outlet effect might also be part of the reason, even if samples of the phytoplankton could not demonstrate higher amounts of plankton downstream of the power plant reservoir than upstream. In late summer the number of filter‐feeding trichopterans has increased and the species composition has changed. Neurclipsis bimaculata and Ceratopsyche nevae have become more abundant and Arctopsyche ladogensis as well as several species commonly found among water moss have disappeared.
Migration of a fast‐growing population of brown trout (Salmo trutta l.) through a fish ladder in relation to water flow and water temperature
Authors: Jensen Arne J. , Aass Per
Published: February 2007

The ascent of brown trout spawners (Salmo trutta L.) in the fish ladder at the Hunder dam on the River Gudbrandsdalslågen, eastern Norway was correlated with water flow and water temperature from 1983 to 1990. Ascent took place from the end of June to the middle of October. The majority of the trout entered the fishway during August and the first half of September. Before arriving at the fish ladder, ascending trout must pass through two sections of river with differing flow regimes and optimum flows for migration. Conditions in the section below the dam are critical for ascent. When discharge over the dam exceeded about 180m3s−1, it was difficult for the fish to locate the entrance to the fishway. High discharges often occurred in June and July, delaying or preventing ascent. At flows below 20m3 s−1 it was difficult for fish larger than 80 cm to approach the ladder entrance. When flow decreased to below 10 m3 s−1, ascent was difficult for all sizes. Water temperature was of less importance. Lengths of brown trout ascending the ladder were most often between 55 and 75 cm. Large fish arrived earlier than small fish, females before males, and naturally recruited fish before stocked fish.
Modelling the effect of groundwater abstraction on salmonid habitat availability in the river Allen, Dorset, England
Authors: Johnson Ian W. , Elliott Craig R. N. , Gustard Alan
Published: February 2007

The River Allen in Dorset, England is regarded as a classic example of a chalk stream and historically has a reputation as a high quality trout and salmon fishery. Since 1946 the Allen has been subject to groundwater abstraction from chalk boreholes situated close to the stream. Significant reductions in salmonid populations in recent years prompted the National Rivers Authority Wessex (now South Western) Region to initiate detailed hydrological, biological and fisheries studies to investigate the perceived problem. As part of these studies the Institute of Hydrology was commissioned to investigate the effect of the historical groundwater abstraction regime on the availability of physical habitat for life stages of trout and salmon (Johnson et al., 1993).

The modelling procedure used the instream flow incremental methodology (IFIM) (Bovee, 1982), which was implemented using the physical habitat simulation (PHABSIM) model (Milhous et al., 1984). Outputs from PHABSIM hydraulic models were combined with habitat suitability data for life stages of trout and salmon to develop habitat (weighted usable area) versus discharge relationships. Habitat suitability indices were developed by the National Rivers Authority Wessex Region by snorkelling and wading in a number of chalk streams similar in character to the Allen.

To assess the impact of groundwater abstraction on the temporal variation of habitat availability, weighted usable area versus discharge relationships were combined with a 20 year time series of mean monthly historical and ‘naturalized’ flows. The resulting time series of historical and naturalized weighted usable areas were analysed using a standard duration curve program to demonstrate the effect of the abstraction on the availability of habitat for each species life stage considered.
0+ fish assemblages in a sector of the Rhôcne river influenced by the bregniér–cordon hydroelectric scheme
Authors: Peň´z Milan , Jurajda Pavel , Roux Albert Luis , Olivier Jean Michel
Published: February 2007

A survey was undertaken to assess the effects of the construction of the Brégnier–Cordon hydroelectric power station in 1984 on the spawning and nursery habitats of the young of the year fish (YOY) in the River Rhǒne floodplain area. No obvious effect could be identified in the most important aquatic habitats studied, possibly due to the downstream drift and dispersion of juvenile fish. Some new habitats were created with a high production capacity, which proved suitable as nursery areas for YOY rheophilous fishes (e.g. riparian zones of the headrace canal and reservoir). The conditions for young fish were also improved in the section of the main channel, now by‐passed, in which the discharge is stabilized and sufficiently high. However, a rapid decline in the abundance and species diversity of YOY fish assemblages was noted in parapotamic side‐arms, caused by the side‐arms drying up and becoming invaded by terrestrial plants. High YOY abundance, indicating good reproductive success, was nevertheless noted in some fishes considered as sensitive to such hydroengineering activities.
Ecological–economic assessment of a sediment‐producing stream behind lower granite dam on the lower snake river, USA
Authors: Brusven Merlyn A. , Walker David J. , Painter Kathleen M. , Biggam Russell C.
Published: February 2007

Field investigations and simulation modelling studies were conducted on an agriculturally perturbed watershed draining into the regulated Lower Clearwater–Snake Rivers of Idaho and Washington. Ecological–economic analyses were conducted to develop an integrated systems framework to assess the impacts of alternative farming practices on sustainable farming, sediment erosion and stream health on Tom Beall Creek, with ecological implications and consequences to Lower Granite Reservoir on the Snake River. A geographic information system (GIS) was used to spatially delineate field boundaries, soil types, drainage patterns and erosion rates. An AGNPS (agricultural nonpoint source) pollution model was interfaced with the GIS to project water quality impacts of land use in the watershed. The AGNPS model was integrated with a mixed integer linear programming model (MIP) to facilitate modelling cost effectiveness on land as it related to eroded soil entering the receiving streams. Biological health assessment was performed using benthic macroinvertebrates. The biological condition of Tom Beall Creek was rated as slightly and moderately impaired for 1992 and 1993, respectively. A wheat–pea rotation under conventional tillage and cross‐slope farming had the highest weighted average on‐site erosion damage of $20 per ha; the lowest damage was $3.63 per ha using a wheat–barley–fallow rotation with reduced tillage and divided slopes. Simulating a ‘no programme’ policy scenario, the MIP model showed the dramatic impact of the current farm programme with conservation compliance in the region of highly erodible land and high participation rate in the government farm programme. Under current farming practices and > 50 yr spring runoff event, it was estimated that nearly 5000 t of suspended solids would be exported from the Tom Beall watershed. During low flow years, less than 200 t were exported.

Sedimentation in Tom Beall Creek is the most debilitating environmental factor impacting the aquatic biota. High erosion rates from all of the anthropogenically impacted streams above Lower Granite Dam tend to shorten the productive storage life of the reservoir, alter the hydroelectric power generating capacity and interfere with the ecological food web and biodiversity. Although the implementation of better conservation practices in anthropogenically disturbed watersheds will not eliminate watershed erosion, it will reduce the frequency and the amounts of sediment dredged from reservoirs in the future, and will reduce on‐site and off‐site costs of erosion and sediment damage.
Geomorphic response to river flow regulation: Case studies and time‐scales
Authors: Church Michael
Published: February 2007

River regulation imposes primary changes on flow and sediment transfer, the principal factors governing the alluvial channel regime. In this study, the effect of flow regulation is isolated from sediment delivery. Peace River (Q̄ = 1080m3s−1, increasing to 2110m3s−1 downstream) was regulated in 1967 for hydropower. The gravel‐bed reach immediately downstream from the dam has become stable. Gravel accumulates at major tributary junctions, so the river profile is becoming stepped. Further downstream, the river has a sand bed. It can still transport sand, so morphological changes along the channel include both aggradation and channel narrowing by lateral accretation. In the gravel‐bed Kemano River (Q̄ = 150m3s−1), the addition of water by diversion from another river caused degradation when additional bed material was entrained below the inflow point. However, the effect became evident only after many years, when a competent flood occurred. The short‐term response was channel widening. The time‐scale for the response depends on the size of the river and the nature and severity of regulation. In both rivers, significant adjustment will require centuries and will intimately involve the riparian forest.
Changes in the hydrological regime and invasions by plant species along riparian systems of the Adour River, France
Authors: Décamps H. , Planty‐Tabacchi A. M. , Tabacchi E.
Published: February 2007

Changes in the hydrological regime affect the phenomenon of invasion by plant species along riparian systems. The dynamics of exotic (non‐native) and native species were examined at five sites that differed in exposure to hydrological disturbance (floods) during three consecutive years (medium, wet and dry years). When considering the disturbance gradient, exotic plants were favoured by direct exposure to floods (main channel) and by high flood frequencies. The response to year to year changes in hydrology was rapid for both native and exotic communities. However, the exotic plants responded more rapidly and were favoured by a dry year. A general framework including human and natural factors involved in invasions by exotic plants along rivers is presented.
Relationships between fisheries and the integrity of river systems
Authors: Welcomme R. L.
Published: February 2007

Human use of river systems has intensified considerably in the last century due to increasing population and the associated higher demand for water through industrial and agricultural technologies. This intensification process has impacted rivers and resident organisms. Natural rivers have rich and varied fish faunas adapted to the variable climate and morphology of such systems. Much of the diversity and resilience can be traced to the connectivity between two very different components, the channel and the floodplain. Fisheries in rivers are as diverse as the fish communities and are adjusted for capturing most species and life stages throughout the year. Fisheries reasonably conducted have proved sustainable with a high rate of catch correlated with the intensity of flooding in the same or preceding years. Fish communities react in a predictable manner to externally imposed stresses, whether eutrophication, induced by humans or natural environmental modification, or fishing, through successive loss of large species and their replacement by smaller, faster growing species. Generally, the overall weight of catch remains little affected by this process until excessive levels of exploitation are reached and the stock collapses. Damage to fish communities through overfishing and environmental modification is widespread. Improvement of the situation demands stricter management of riverine systems through the protection of the few that remain in a relatively pristine state, and those modified should be restored if social, political and economic conditions allow. Should this not be possible, approaches to the mitigation of externally imposed stresses should be sought and applied.
Light availability and growth of wildcelery (Vallisneria americana) in upper Mississippi River backwaters
Authors: Kimber Anne , Owens Jennifer L. , Crumpton William G.
Published: February 2007

Large beds of Vallisneria americana declined in the backwaters of the Upper Mississippi River after a drought that occurred between 1987 and 1989. One hypothesis for this decline is that low light availability may have decreased net photosynthesis to the extent that overwintering tubers were not formed. Following the decline, light availability remained low. To determine what light levels would be necessary for the re‐establishment of Vallisneria in the Upper Mississippi River, the long‐term growth of plants in a backwater lake and in an experimental pond was measured while the surface and subsurface light were monitored continuously. Plants grown from tubers transplanted to 0·5, 1·0 and l·5m depth in the lake grew and produced tubers only at 0·5m depth (9% of surface light). At 1·0 m, light availability was less than 1% of the surface light. Plants grown from tubers in experimental ponds with four shade treatments (2, 5, 9 and 25% of surface light) for the same growing period produced replacement‐weight tubers in 9% light. For a longer growing season, plants also produced replacement‐weight tubers in treatments with at least 5% of surface light.

An average light‐extinction coefficient of 4·64 m−1 was calculated for the backwater lake based on continuous data collected during 94 days during the growing season from eight widely separated sites. Using equations based on the average extinction coefficient for the lake and average leaf lengths of plants grown in experimental ponds, we predict that in years with comparable turbidity, plants grown from locally collected tubers will grow and produce replacement tubers only at depths of 0·8 m or less.
Primary production and light dynamics in an upper Mississippi River backwater
Authors: Owens Jennifer L. , Crumpton William G.
Published: February 2007

In nutrient‐rich systems, phytoplankton production is frequently light‐limited and light attenuation can become a critical factor controlling the rates of production, especially in shallow systems subject to wind resuspension of sediments. This study examined the relation between light availability and primary production in Lake Onalaska, a shallow, nutrient‐rich impoundment of the Upper Mississippi River. Continuous water quality monitors recorded dissolved oxygen, temperature and light flux at a network of sites from July to September 1990 and these data were used to estimate the primary production, light availability and light attenuation coefficients. The gross primary production averaged 2·2gCm−2 day−1 and was due almost entirely to phytoplankton. Production was strongly light‐limited, with most of the light attenuation due to non‐algal components, possibly related to wind resuspension in this shallow system. Regression analyses revealed significant effects of wind speed and direction on light attenuation.
Hydrodynamic model of vessel‐generated currents
Authors: Stockstill R. L. , Martin S. K. , Berger R. C.
Published: February 2007

The drawdown and return currents of vessels navigating in channels have previously been described by empirical relations or by using physical models. The empirical solutions are generally limited in scope to idealized channel shapes. Physical models are unrestricted in this respect, but have limitations related to expense and scale effects. In this paper, vessel effects are modelled numerically. The vessel's displacement is represented by a moving pressure field. The movement of the pressure field is spatially varied in time, representing a vessel navigating along a channel. The hydrodynamics are described using the two‐dimensional shallow water equations, which are modified to account for the effects of the imposed pressure field. A Petrov—Galerkin finite‐element scheme using characteristic‐based weighting is used to solve the governing equations. This Petrov—Galerkin test function is specifically designed to model flow fields containing large gradients such as those found in the vicinity of the moving vessel. The numerical results for return flows and water surface elevations are compared with flume results of vessel passages.
Analysis of water level management on the upper Mississippi River (1980–1990)
Authors: Wlosinski Joseph H. , Hill Lara
Published: February 2007

Management at 27 low‐head dams affects water surface elevations for a 1050km stretch of the Upper Mississippi River (UMR) between St Louis, Missouri and Minneapolis, Minnesota. A systemic overview is given of current operating plans at dams on the UMR and historical data are analysed to determine how well the operating plans are being met. Water level elevations at all 27 dams are regulated as a function of discharge, although plans are specific for each dam. The management objective is to maintain a target water level at specific locations (control point) in each impoundment over specific ranges of discharge. The target water level and control point may change as discharge changes in each impoundment. In some of the impoundments water regulation causes drawdowns below the elevation for which the dams were planned, and at other dams no drawdown occurs. During the navigation seasons of 1980 to 1990, water levels were within their target window for an average of 72·5% of the time for 25 dams analysed. Difficulties in meeting targets are caused by winds, local rainfall events, ice dams and rapidly fluctuating discharges from tributaries with upstream reservoirs used for peaking hydropower.
Environmental considerations for assessing dam removal alternatives for river restoration
Authors: Shuman John R.
Published: February 2007

Dam removal has received increasing attention over the last several years as a viable alternative to rehabilitation of unsafe dams and as an alternative for consideration as many hydroelectric dams come up for relicensing in the USA. The environmental impacts of dams on river ecosystems have been studied far more extensively than have the impacts of removing dams. Comprehensive environmental research is currently being conducted, assessing both the positive and negative impacts of the possible removal of Rodman Dam on the Ocklawaha River, Florida. The 2073 m long and 6·7 m high dam was constructed in 1968, impounding 3642 ha on this 125 km long river. The impacts of dam removal are compared with those expected by retaining and actively managing the reservoir for fish and wildlife. The research approach described here for addressing alternatives is recommended as a holistic procedure in which to make an environmentally based decision regarding dam removal.
Effects of an experimental flood on litter dynamics in the middle rio grande riparian ecosystem
Authors: Molles Manuel C. , Crawford Clifford S. , Ellis Lisa M.
Published: February 2007

The objectives of the study were to measure the effects of an experimental flood on : (1) leaf litter production by the riparian forest; (2) leaf decomposition; and (3) the amount of forest floor organic matter. The study area is located at Bosque del Apache National Wildlife Refuge, approximately 160 km south of Albuquerque, New Mexico. Experimental and reference study sites of about 3·1 ha were both located in cottonwood (Populus fremontii) riparian forests that had not been flooded for approximately 50 years. The experimental and control study sites were sampled for two years before flooding the experimental site. The experimental flood peaked on about 31 May, the average date of peak flow in the 100 year hydrograph for the USGS gauging station on the Rio Grande at Embudo, New Mexico. Litter fall was lower at the flood site than at the control site, whereas the rate of leaf decomposition was higher at the flood site during the period of inundation. However, the flood did not produce a measurable response in standing stock of forest floor litter. This pool of carbon may require the cumulative effects of several years of flooding to show a measurable response.
Water allocation for ecosystem management of the Missouri River
Authors: Hesse Larry W.
Published: February 2007

Historically the hydrograph of the Missouri River had high and low discharge components. Low flows occurred from July through to early March. The period was characterized by declining thalweg velocity, reduced depth and exposed sand bars. Flood control was initiated as early as 1937 when the first mainstem dam was completed: however, it was not until after 1944 that a rigorous effort to control the wild Missouri River occurred. By 1954 sufficient reservoir storage had been built to allow complete re‐organization of the hydrograph to minimize floods and facilitate navigation. The present managed hydrograph (plan III) is compared with four operational alternatives. Plan I was selected by a team of environmental advisers and it was patterned after the natural hydrograph, but with some adjustments to minimize flood damage and to provide only minimal benefits to navigators. Plan II was selected as the preferred alternative in the environmental impact analysis and it was much more sensitive to the preservation of flood control and navigation benefits. Plan IV was a run of the river alternative, but with the reservoirs present, and, finally, plan V was a true run of the river under pre‐dam conditions.
Ecological integrity and fisheries ecology of the Araguaia—Tocantins River Basin, Brazil
Authors: Ribeiro Mauro César Lambert de Brito , Petrere Miguel , Juras Anastácio Affonso
Published: February 2007

An attempt is made to evaluate the present environmental impacts of the Tucuruí dam on the fisheries and ecological integrity of the Araguaia—Tocantins basin. Management and research needs to minimize the impacts from future hydroprojects and increased human activities in the basin are also addressed. The Tocantins and Araguaia fish fauna is not especially rich by Amazonian standards (about 300 species). Total yields are also rather low (about 8800 t/y) in a river stretch of about 2500 km and unique for being concentrated (90%) in the main channel. Fisheries are heavily dependent on migratory fish and may be severely damaged as a consequence of river regulation. Downstream from the Tucurui Dam important fisheries have been drastically reduced (70%), probably by recruitment failure, lower productivity and overfishing. Upstream from the dam, however, fisheries have benefited from the higher productivity of the artificial lake, although this has not compensated for the regional economic shortages. Management based on ‘basinwise’ catch statistics and fish migration research should take account of likely future disruptions of commercial fisheries by the synergistic effects of other planned impoundments, mining, deforestation and uncontrolled sport fisheries in the middle and upper basins.
Population, environment and sustainability: Reconstructing the debate
Authors: Dovers Stephen R. , Norton Tony W.
Published: February 2007

This article seeks to integrate the population‐environment and sustainable development debates within an integrative approach to sustainability. Reference is made to both global and Australian situations. Common constructions of the debates are briefly critiqued. These issues are addressed via an integrative approach to sustainability, which is described through definitions that differentiate sustainability and sustainable development, and a set of principles that support these definitions. The principles include: extending temporal and spatial scales, appreciation of pervasive ignorance and uncertainty, the need for long term social and ecological goals, and greater cognisance of consumption (demand) aspects.
Sustainable health? primary health care and selective alleviation
Authors: Gerhardt Chloe
Published: February 2007

This paper suggests that there needs to be consideration of what is sustainable health, a definition of which should look beyond the feasibility of maintaining biomedically oriented health strategies. Such a definition needs to be located within a health sensitive development framework. The paper examines some of the debates around appropriate primary health care and looks in particular at health programmes aimed at intervening in diarrhoeal episodes.
Sustainable development in a region: A practical approach to targeting environmental impacts
Authors: Hunt Colin
Published: February 2007

In this paper a model is put forward for setting targets for ecologically sustainable development in a region. The approach is practical and should be applicable to any region. A case study approach facilitates the development of the environmental impact model of Ehrlich and Holdren (1974). Targets for a region's population and water quality are discussed in some detail with the help of the model. The region, the far north of Queensland, Australia, is centred on the Cairns district, which is growing rapidly due to tourism, but is impacting surrounding valuable ecosystems. As well as exploring the environmental impacts of change in the interacting variables of population, consumption and technology, the article contains discussion on setting environmental rehabilitation targets. Major regional externalities would be removed by the achievements of regional water quality improvements. However, other externalities could be generated by the imposition of a limit on regional population. A regional inventory is exampled which could form the basis for regional and (collectively) national environmental accounting.
The sustainable company: The need for environmental concern
Authors: Vinten Gerald
Published: February 2007

Environmental awareness in the general community is at a high level. There is a feeling that time is running out in the quest for global solutions to global problems. It is inevitable that the role in this of commerce and industry should be discussed, and that companies are coming under pressure to demonstrate that their policies are environmentally sustainable. Thirteen reasons are substantiated as to why companies are becoming involved, and non joiners or half‐hearted joiners need to weigh up the risks they are taking. They may become outliers and corporate pariahs, and find that abuse of the environment is equated with abuse of the public and customer, and that both market share and share valuation will suffer accordingly. With a new British Standard on Environmental Management Systems, with a cross‐link to the European eco‐audit scheme, and the growth of green advertising, the environment is at long last receiving the attention it deserves.
Implementing environmental policy in Scotland: The role of the voluntary sector
Authors: McCulloch Alistair , Moxen John
Published: February 2007

Despite the increasing interest in environmental policy and its implementation, little attention has been paid to the role played by the voluntary sector. However, in the UK this sector is actively involved by the Government as an agency of implementation. In this respect, The Scottish Office has established two mechanisms whereby it channels support to a number of voluntary organisations and this article examines the success achieved by these programmes in delivering The Scottish Office's objectives for the voluntary environmental sector. The conclusion is reached that these mechanisms are generally successful, but that there are a number of failures regarding the achievement of the immediate policy objectives. Additionally, while the programmes deliver good work that is in line with the Government's policy objectives, the contribution they make to sustainable development (the primary objective of the strategy laid down in its White Paper, This Common Inheritance) could be improved. They do, however, represent an example of relatively successful policy implementation.
Conceptualizing a corporate environmentalism model
Authors: Lang Josephine Chinying
Published: February 2007

Environmental legislation now looms large in the backdrop of corporate strategy. However, there is still little theoretical work on corporate environmentalism. A conceptual model of corporate environmentalism is proposed here, stressing the effect of information on managerial enthusiasm in responding to the green challenge and on the formalization of strategies and structures to reflect that response. Suggestions on operationalization are advanced and research implications discussed.
Beyond eco‐efficiency: Towards socially sustainable business
Authors: Gladwin Thomas N. , Krause Tara‐Shelomith , Kennelly James J.
Published: February 2007

An earlier version of this paper was presented by Dr Gladwin at the First Annual Senior Executives' Seminar on ‘Sustainability and Profitability: Conflict or Convergence’ sponsored by the HRH the Prince of Wales's Business & the Environment Programme and developed by the University of Cambridge Programme for Industry, Cambridge, UK, September 1994. The authors express their appreciation to AT&T, the Energy Foundation, the Management Institute for Environment and Business and the Merck Family Fund for their support of ‘The Global Environment Program’ at New York University, which partially financed preparation of this paper. The viewpoints herein should be attributed only to the authors.

Sustainability, in most corporate gatherings and initiatives, has been conceptualized as something mainly having to do with eco‐efficiency, involving pollution prevention and resource conservation in the Northern Hemisphere. It is asserted here that eco‐efficiency is a necessary, but not sufficient, prerequisite for full sustainable development. Socio‐economic sustainability – involving poverty alleviation, population stabilization, female empowerment, employment creation, human rights observance and opportunity redistribution on a massive scale – is equally important, although perhaps infinitely more intractable. Although calls for corporate engagement in progressive social change have often been resisted in the past, we argue that the somber social state of the world, diminished governmental capacities and enlightened corporate self‐interest demand that private enterprise must now assume greater responsibility for human development on a global scale. After reviewing a broad array of indicators and origins of social unsustainability a set of working principles of socially sustainable business is proposed. A concluding section pinpoints the tasks of transformational leadership needed for redirecting corporations to the cause of ensuring a sustainable future.