bluuebunny/crossref_metadata_2025_split huggingface dataset:
All‐electron all‐virtual spinor space relativistic coupled‐cluster calculations for molecules of heavy elements using contracted basis set: Prediction of atomization energy of PbH4*
Authors: Malli Gulzari L. , Siegert Martin , Turner David P. 
Published: May 2008

AbstractAll‐electron all‐virtual spinor space (AVSS) relativistic second order Møller–Plesset (RMP2), coupled‐cluster singles doubles (RCCSD), RCCSD(T) (RCCSD plus the triple excitation correction included perturbationally) calculations are reported for tetrahedral (Td) PbH4 at various bond lengths using our finite contracted universal Gaussian basis set. Our relativistic calculations predict the RMP2, RCCSD, and RCCD(T) molecular correlation energy for PbH4 as −2.2563, −2.1917, and −2.2311 au, respectively. Ours are the first AVSS RMP2, RCCSD, and RCCSD(T) molecular calculations for electron correlation energy of the heavy element molecule PbH4. All‐electron AVSS coupled‐cluster calculations for the Pb atom are also reported and these were used (in conjunction with the corresponding molecular electron correlation energy calculations for PbH4) to predict atomization energy (Ae) of PbH4 at various levels of coupled‐cluster electron correlation. Our predicted atomization energy for PbH4 (at the optimized bond length of 1.749 Å) with our Dirac–Fock, RMP2, RCCSD, and RCCSD(T) calculations is 5.73, 7.27, 11.24, and 11.62 eV, respectively. Neither such relativistic molecular correlation energy nor atomization energy has been reported so far for heavy polyatomic with 86 electrons. Calculation of relativistic molecular correlation energy is no more a nightmare, and bottlenecks are broken for the calculation of relativistic correlation as well as atomization energy for molecules of heavy elements. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Accurate Born–Oppenheimer calculations of the low‐lying c3Σ and a3Σ excited states of helium dimer
Authors: Pavanello Michele , Cafiero Mauricio , Bubin Sergiy , Adamowicz Ludwik 
Published: May 2008

AbstractAccurate variational Born–Oppenheimer calculations of the two lowest excited Σ triplet states of the helium dimer at their respective equilibrium geometries are reported. The wave functions of the states are expanded in terms of explicitly correlated Gaussian functions with shifted centers. The obtained energies are the best variational estimates ever calculated for these states. One‐electron densities are also presented and discussed. The results are compared with the experimental values and previous calculations. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Detecting biological responses to flow management: missed opportunities; future directions
Authors: Souchon Yves , Sabaton Catherine , Deibel Robert , Reiser Dudley , Kershner Jeffrey , Gard Mark , Katopodis Christos , Leonard Paul , Poff N. Leroy , Miller William J. , Lamb Berton Lee 
Published: May 2008

AbstractThe conclusions of numerous stream restoration assessments all around the world are extremely clear and convergent: there has been insufficient appropriate monitoring to improve general knowledge and expertise. In the specialized field of instream flow alterations, we consider that there are several opportunities comparable to full‐size experiments. Hundreds of water management decisions related to instream flow releases have been made by government agencies, native peoples, and non‐governmental organizations around the world. These decisions are based on different methods and assumptions and many flow regimes have been adopted by formal or informal rules and regulations. Although, there have been significant advances in analytical capabilities, there has been very little validation monitoring of actual outcomes or research related to the response of aquatic dependent species to new flow regimes. In order to be able to detect these kinds of responses and to better guide decision, a general design template is proposed. The main steps of this template are described and discussed, in terms of objectives, hypotheses, variables, time scale, data management, and information, in the spirit of adaptive management. The adoption of such a framework is not always easy, due to differing interests of actors for the results, regarding the duration of monitoring, nature of funding and differential timetables between facilities managers and technicians. Nevertheless, implementation of such a framework could help researchers and practitioners to coordinate and federate their efforts to improve the general knowledge of the links between the habitat dynamics and biological aquatic responses. Copyright © 2008 John Wiley & Sons, Ltd.
Growth and voltinism in the aquatic insects of a regulated river subject to groundwater inflows
Authors: Fjellheim Arne , Raddum Gunnar G. 
Published: May 2008

AbstractThe water temperature and discharge of the Vassbygdelvi River, Aurland watershed, was altered after regulation due to transfer of cold water from the higher parts of the catchment. The lower part of the river receives a considerable amount of groundwater, which affected the water temperature due to reduced discharge. Compared to a closely situated reference station, the temperature increased by 9% on a yearly basis. The temperature differences were most pronounced during the winter when average January water temperature at the reference and the stretch influenced by groundwater was 0.8 and 3.3°C, respectively. Studies of benthic insects in the two habitats showed that the temperature differences had little effect on the length of the life cycle. Although some species show significant differences in growth pattern during parts of the year, with more rapid development in the winter‐warm locality, there was a trend for synchronous growth at both localities. Compared to the situation before regulation, two species of stoneflies became extinct and one mayfly species colonized the area, probably as a result of the increased number of annual degree‐days. Copyright © 2008 John Wiley & Sons, Ltd.
Changes in macroalgae and bottom fauna in the winter period in the regulated Alta River in Northern Norway
Authors: Koksvik Jan Ivar , Reinertsen Helge 
Published: May 2008

AbstractThe study was carried out in the upper part of the Alta River (69°58N; 23°24E), on a 3 km stretch that is not covered by ice due to increased winter temperatures after hydroelectric power development in 1987. The aim was to detect potential effects on the macroalgae and bottom fauna from the altered physical conditions. The presented data, based on Surber samples, describe the late winter situation (March to May) for the macroalgae (1996–2004) and the bottom fauna (1993–2004). The maximum biomasses of algae showed a highly significant decline from close to 200 g dry weight (ash free) m−2 in 1996 to less than 50 g dry weight m−2 in the last years of the investigation. Microspora amoena was the overall dominating species in the first phase of the study and Didymosphenia geminata in the last 5 years. Ulothrix zonata and Hydrurus foetidus were common throughout the entire study. A highly significant linear decline (r2 = 0.752, p = 0.001) was found in the total bottom fauna densities, showing means from 9500 to 16 000 ind. m−2 in 1993–1996 and from 2200 to 2700 ind. m−2 in 2001–2004. The reduction primarily concerned Chironomidae larvae. The mean biomass of the bottom fauna did not change to the same extent due to low individual weight of the Chironomidae larvae. A strong correlation between algal biomass and bottom fauna density was found (r2 = 0.796, p = 0.0029). The study demonstrates a eutrophication effect in the ice‐free river section following the regulation. The effect decreased through the investigated period and terminated 13–15 years after the regulation took place. Copyright © 2008 John Wiley & Sons, Ltd.
Response of migrating chinook salmon (ONCORHYNCHUS TSHAWYTSCHA) smolts to in‐stream structure associated with culverts
Authors: Kemp Paul S. , Williams John G. 
Published: May 2008

AbstractPoorly designed culverts can impede upstream movements of fish under high flows when excessive water velocities create adverse conditions. Improvement in upstream fish passage efficiency may occur with placement of structures within culverts that increase hydraulic complexity and provide resting areas. The effects of structural modification on downstream migrants, however, are unknown. To address this gap in knowledge, the behaviour of Chinook salmon (Oncorhynchus tshawytscha) smolts was assessed in an experimental laboratory flume. Under light and dark conditions, fish were observed as they encountered either an unmodified aluminium channel (control) or one of two treatments: an ‘intermediate’ substrate (treatment channel lined with corrugated sheet) or a ‘complex’ substrate (addition of cobbles to the ‘intermediate’ treatment). More smolts passed the control channel than the treatment channels. Even with control of the variation in flow between channels, under light conditions more fish than expected passed the control channel when paired with the complex treatment. Smolts more frequently rejected both treatments than the control channel when light, and the complex treatment when dark, by swimming upstream against the flow after entry. The majority of fish moved through the flume facing downstream, although a greater proportion faced upstream when dark than when light, and entered the control channel. Velocity of downstream movement (ground velocity) was greater through the control channel than for the treatment routes, and slower than the mean water velocity, and under the dark condition. When mean water velocities were taken into account, the net velocity through the control channel was not significantly different to the intermediate, and lower than the complex channel. Juvenile Chinook salmon determined fine‐scale variation in structural complexity and exhibited avoidance behaviour in the presence and absence of visual stimuli. Hydraulic stimuli influenced route selection exhibited by migratory juvenile salmonids. Copyright © 2008 John Wiley & Sons, Ltd.
Overwintering and downstream migration of sea trout (Salmo truttaL.) kelts under regulated flows—northern Sweden
Authors: Östergren Johan , Rivinoja Peter 
Published: May 2008

AbstractPost‐spawning migrations of sea trout (Salmo truttaL.) in two northern Swedish river systems, Vindelälven and Piteälven, were studied. Telemetry was used to evaluate spawning locations, post‐spawning mortality, overwintering survival/habitat selection/location, partitioned natural mortality from dam passage mortality and overall survival from post‐spawning to the sea entry. Fifty‐eight sea trout (LT = 50–86 cm) were radio‐tagged at the beginning of their spawning migration from June to September in 2003 and 2004, and their spawning in September and October each year was monitored. In total, 91% (n = 53) survived spawning and were thus defined as kelts. Of these, 92% (n = 49) overwintered under ice‐cover in deep, slow flowing sections of the rivers. Overwintering mortality was low, on average 8%. The main seaward migration occurred during May and June and was initiated when ambient water temperatures exceeded 4–6°C, independent of the start of the spring flood when flows rose to 1000 m3 s−1. The highest downstream migration speed was approximately 25 km 24 h−1and migrations mainly took place at daytime. During seaward migration, the kelts encountered hydropower stations that lacked bypass systems for fish passage, which delayed their downstream migrations. Passage mortality at the power stations was 69 and 25% in the Vindelälven and Piteälven, respectively. These losses, combined with the naturally high winter survivals of kelts at the unregulated river parts, underline the importance of developing safe passage routes for kelts at hydropower facilities for conserving sea trout populations in regulated rivers. Copyright © 2008 John Wiley & Sons, Ltd.
Influence of hydrological regimes on the pre‐spawning entry of Atlantic salmon (Salmo salar L.) into an upland river
Authors: Tetzlaff D. , Gibbins C. , Bacon P. J. , Youngson A. F. , Soulsby C. 
Published: May 2008

AbstractThe Girnock Burn is an Atlantic salmon (Salmo salar) spawning tributary of the river Dee, Aberdeenshire, Scotland. The dates, sexes and numbers of adult salmon entering the stream in the three months prior to spawning were determined between 1969 and 2005 using a permanent fish‐trap. During this time, the number of fish returning to spawn varied markedly. Here we analyze the whole of this unique long term data set in order to characterize and classify the hydrologic regimes of the pre‐spawning migration period and assess the extent to which these regimes help explain the timing and patterns of arrival of adult salmon into the stream. A range of flow parameters was calculated for the arrival period (September–November) for each of the 37 years. These parameters were used to ordinate and classify years according to their flow regimes. The analysis yielded six distinct groups or ‘flow regime types’ which separated principally in relation to flow magnitude and frequency parameters. The number of fish entering the burn on a given day was not significantly correlated to discharge on that day. However, patterns of arrival of fish differed markedly between years with different regime types, with the number of fish arriving on a given day related to patterns of discharge over the preceding part of the arrival period. Overall inter‐annual variability in entry corresponded to the defined regime types. In wetter years, fish entry to the stream usually starts relatively early and continues throughout the pre‐spawning period. In contrast, dry years may result in fish entry being delayed; this may result in lower numbers of spawning females entering the stream and sub‐optimal utilization of juvenile habitat in the following spring. Copyright © 2008 John Wiley & Sons, Ltd.
Field study of an attraction channel as entrance to fishways
Authors: Lindmark Elianne , Gustavsson L. Håkan 
Published: May 2008

AbstractA flow device that accelerates turbine tail water (or any free stream) to act as an attraction for migrating fish is field tested. The device consists of an open (U‐shaped) channel which accelerates the incoming flow by a local constriction of the cross‐sectional area. The velocity increase has previously been investigated in a lab‐scale model and an increase of 38% has been established. In the summers of 2004 and 2005, a full‐scale prototype of the attraction channel was tested at the Sikfors hydropower plant in the Pite River in Sweden. The channel was equipped with underwater cameras to monitor and record the fish swimming through it. The tests show that the fish do swim through the attraction channel. During the same time period in 2004 and 2005, 57 and 471 fishes swam through the channel, respectively. The major change of the channel between the two years was that it was painted black for 2005. Copyright © 2008 John Wiley & Sons, Ltd.
Random displacement versus habitat choice of fish larvae in rivers
Authors: Wolter Christian , Sukhodolov Alexander 
Published: May 2008

AbstractNumerous studies elaborated habitat preferences of early juvenile fish. However, detailed analyses of swimming performance of fish larvae and early juveniles revealed substantial doubts about their ability to maintain positions in the river and to choose habitats. It was hypothesized that the juveniles will be randomly distributed by turbulent flows initially, and that the match with suitable nurseries depends on the shore line heterogeneity. Low swimming performance of juvenile fish, as compared to the flow velocities in rivers, allows consideration of a longitudinal dispersion model as a tool to predict the spatio‐temporal patterns of juvenile fish assemblages, e.g. downstream of a spawning site. Because of variable geometry of the river channel, longitudinal dispersion should be expanded with equations describing the effect of stagnant flow zones which can also act as the refuge. In this study a model of dispersion processes with non‐transit zones was developed and validated for the lowland Müggelspree River, Germany. Computations with the model provide the possibility to explore the effect of flow and channel geometry on the distribution history of juvenile fish. Particularly, the model allows in a probabilistic way to estimate for the portion of juvenile fish retained in non‐transit zones of the flow and subsequently of the portion transported downstream to the lakes, and thus, finally, to assess the importance of random displacement for the spatial structure of the juvenile fish assemblage in a river. Copyright © 2008 John Wiley & Sons, Ltd.
The role of seedbanks in restoration of floodplain woodlands
Authors: Jensen Anne E. , Walker Keith F. , Paton David C. 
Published: May 2008

AbstractPlant communities on the River Murray floodplain, South Australia, are degraded by flow regulation and salinization, with up to 95% of eucalypt trees being dead or dying from water stress. This paper describes the floodplain seed bank and its capacity to respond to floods or managed ‘environmental flows’. The soil seed bank contained mainly annual native species, particularly chenopods, whereas the dominant trees, river red gum and black box (Myrtaceae: Eucalyptus camaldulensis, E. largiflorens), retained most of their seeds in a canopy seed bank (‘serotiny’). In healthy trees, seed release peaked in summer (December– February for river red gum, October–March for black box), but variable volumes suggested cyclical patterns in seed crops. Seed release, viability and germination rates did not appear to limit recruitment. In water‐stressed trees, however, seed release was up to nine‐fold less. Germination requires water from floods or local rainfall. Flow regulation has reduced flood frequencies and delayed timing, so that germination now is likely to be followed by relatively hot, dry conditions (summer). Following managed watering events, seeds accumulated in high‐water strandlines, where they germinated readily under a mulch of organic litter, but survival was limited. The importance of local rainfall as a complementary water source was demonstrated, and survival rates were higher for rain‐triggered germinants, compared to seedlings germinating in strandlines created by managed watering. Seedling survival would be greater if environmental flows were delivered to complement local rainfall or to extend the effect of short flood events. Copyright © 2008 John Wiley & Sons, Ltd.
Measurement of force components for ink detachment of newsprints
Authors: Pan Jolly , Nguyen Kien L. 
Published: May 2008

AbstractInk detachment tests were carried out using a Couette device. During the test, the energy supplied to the operation of the device partially dissipated as heat. The fraction of energy dissipated increased with pulp consistency. The fraction of energy for peeling and pulling the ink from the printed samples were calculated. At 4% consistency, the energy for pulling was much higher than for peeling, while at higher consistencies, the peeling effect became more significant. The ink detachment was highly dependant on how the pulp interacted with the printed surface. This interaction was influenced by pulp consistency and the energy applied to the rotor of the Couette device. Copyright © 2008 John Wiley & Sons, Ltd.
Electron transport simulations of a multilead system using the impulse‐response method
Authors: Suzuki Taku , Goto Hidekazu , Hirose Kikuji 
Published: May 2008

AbstractWe introduce a computational procedure for designing nanoscale electronic devices using an impulse‐response method, which is an originally developed simulation method within the framework of real‐space finite‐difference formalism. The impulse‐response method is a new computational scheme for computing the scattering wave function for an incident electron with arbitrary energy in which the impulse wave function is adopted as an initial state of the time evolution. In applying the impulse‐response method to electron transport simulations of two‐dimensional multilead systems, we discuss and illustrate the feasibility of designing a nanoscale multilead electron transportation system. Copyright © 2008 John Wiley & Sons, Ltd.
Antidepressant treatments regulate matrix metalloproteinases‐2 and ‐9 (MMP‐2/MMP‐9) and tissue inhibitors of the metalloproteinases (TIMPS 1–4) in the adult rat hippocampus
Authors: Benekareddy Madhurima , Mehrotra Purvi , Kulkarni Vaishali A. , Ramakrishnan Parvathy , Dias Brian G. , Vaidya Vidita A. 
Published: May 2008

AbstractAntidepressants induce structural remodeling in the adult hippocampus, including changes in dendritic arbors, axonal sprouting, neurogenesis, and endothelial cell proliferation. Such forms of structural plasticity take place in the context of the extracellular matrix environment and are known to be regulated by matrix metalloproteinases (MMPs), in particular MMP‐2/9, and their endogenous regulators, the tissue inhibitors of the metalloproteinases (TIMPs 1–4). Given the hippocampal structural remodeling associated with antidepressant treatments, we hypothesized that antidepressants may regulate the expression and activity of MMP‐2/9 and TIMPs 1–4. The influence of distinct classes of antidepressants, namely, electroconvulsive seizure, fluoxetine, tranylcypromine, and desipramine, on the gene expression of MMP‐2, MMP‐9, and TIMPs 1–4 in the hippocampus was determined using radioactive in situ hybridization. In addition, zymography studies addressed the regulation of the gelatinase activity of MMP‐2/9 following acute and chronic antidepressant administration. We observed that acute and chronic ECS differentially regulate the transcript levels of MMP‐2/9 and TIMPs 1–4 and also increase gelatinase activity in the hippocampus. Acute and chronic pharmacological antidepressants on the other hand differentially alter the expression of the TIMPs without any observed effect on hippocampal MMP‐2/9 expression or activity. These findings raise the possibility that extracellular matrix modifying enzymes and their endogenous regulators may serve as targets for antidepressant treatments and suggests the possibility that they may contribute to antidepressant‐mediated structural plasticity in the hippocampus. Synapse 62:590–600, 2008. © 2008 Wiley‐Liss, Inc.