bluuebunny/crossref_metadata_2025_split huggingface dataset:
Distribution of aquatic vascular plants in lowland rivers: separating the effects of local environmental conditions, longitudinal connectivity and river basin isolation
Authors: DEMARS BENOÎT O. L. , HARPER DAVID M. 
Published: February 2005

Summary1. Changes in species distributions along rivers have rarely been observed independently of changes in environmental conditions and meaningful comparison between different catchments is made difficult by the limited geographical distribution of species. This study presents a new approach to quantify the effect of the spatial structure of lowland river networks on aquatic plant distribution and to explore the potential underlying processes using species life‐history characteristics.2. Twenty‐five species of aquatic vascular plants recorded in 62 sites across five calcareous river basins were used to investigate (i) the temporal turnover of plant species, (ii) the habitat utilisation of species, (iii) the trade‐offs between different plant life‐history characteristics and (iv) the relationship between species life‐history characteristics and habitat utilisation.3. The annual plant turnover within a 3‐year period was, although significant, extremely low. It suggests that results from spatial surveys conducted over 3 years should not be undermined by temporal changes.4. Spatial connectivity along and between rivers was more important than in‐channel physical characteristics in shaping species assemblages. Neither chemical factors (ammonium, phosphate) nor extrinsic biotic competitors (filamentous green algae) significantly influenced plant distribution.5. The most common combinations of life‐history characteristics were neither related to environmental conditions nor to spatial isolation. Instead, they could reflect natural selection processes associated with larger scales than those considered in this study.6. Plant distribution was most strongly related to the dispersal and regeneration abilities of the plants, supporting the hypotheses relating to longitudinal connectivity. The hypothesis that different growth forms would be associated with different in‐channel physical features was not verified. As expected, there were no substantial differences in plant life‐history characteristics between river basins.
Nutrient release and resuspension generated by ruffe (Gymnocephalus cernuus) and chironomids
Authors: TARVAINEN MARJO , VENTELÄ ANNE‐MARI , HELMINEN HARRI , SARVALA JOUKO 
Published: February 2005

Summary1. Benthivorous fish may play an important role in internal nutrient loading. Ruffe are highly specialised, feeding exclusively on bottom animals; thus all nutrients released via their feeding are derived from the bottom and are new to the water column. The fish can also release nutrients from the sediment through resuspension while searching for food.2. The aim of this study was to estimate experimentally in the laboratory the effect on water quality of resuspension and nutrient release by ruffe and bottom animals (chironomids).3. Ruffe released nutrients during 8 h experiments as follows: total P 1.4, dissolved PO4 0.6, total N 24.0 and NH4‐N 15.9 μg g−1 WW h−1. A decreasing trend in mass‐specific release was observed over time, probably because of starvation. The mass‐specific release of total N and NH4‐N decreased as the mean weight of fish increased. The mean ratio of excreted N : P was 32.4. In 26 h experiments with sediment and both ruffe and chironomids, ruffe increased nutrient concentrations and turbidity values significantly but chironomids had an effect only on turbidity. Neither ruffe nor chironomids affected the ratio of inorganic N : P concentrations. An interaction between ruffe and chironomids was found for turbidity.5. According to these results, benthivorous fish may increase nutrient concentrations in the water column and need to be taken into account when estimating internal loading.
Ultraviolet and temperature effects on planktonic rotifers and crustaceans in northern temperate lakes
Authors: PERSAUD ANURANI D. , WILLIAMSON CRAIG E. 
Published: February 2005

Summary1. Anthropogenic stressors such as climate change, ozone depletion and acidification may act in concert to alter ultraviolet (UV) light and temperature regimes in freshwater ecosystems. These physical and chemical changes will inevitably affect zooplankton community dynamics, but little is known about their relative effects on different species in natural communities. During spring, species that migrate to surface waters to take advantage of warmer temperatures may be especially vulnerable as UV levels can be high.2. The objective of this study was to investigate the in situ effects of UV and temperature on a natural assemblage of planktonic rotifers and crustaceans during the spring. We performed in situ exposure experiments in two lakes with different surface temperatures.3. Exposure to UV had a significant effect on the abundance and/or reproduction of four rotifers: Gastropus spp., Kellicottia bostonensis, Kellicottia longispina, Keratella spp.; two cladocerans: Holopedium gibberum, Daphnia catawba, and one copepod: Leptodiaptomus minutus. Incubation under cooler temperatures had a negative effect on K. longispina and H. gibberum. Temperature and UV had a significant interactive effect on abundance and/or reproduction of L. minutus and Ploesoma truncatum. Our results indicate that changes in underwater UV and temperature can significantly influence the composition of the zooplankton community and ultimately food web dynamics.
Temporal variation in body composition (C : N) helps explain seasonal patterns of zooplankton δ13C
Authors: MATTHEWS BLAKE , MAZUMDER ASIT 
Published: February 2005

Summary1. The stable carbon isotope ratio δ13C is a useful tracer of energy flow in lake food webs, and the zooplankton signature is commonly used to establish a baseline for the pelagic habitat. However, sources of temporal variability in the δ13C of different zooplankton taxa are rarely considered.2. Here, we investigate to what extent temporal variation in the δ13C of particulate organic matter (POM) (<41 μm) and the C : N of zooplankton can explain the temporal variability in δ13C of freshwater zooplankton. We compare temporal patterns of δ13C and C : N for Daphnia, Hesperodiaptomus franciscanus and Leptodiaptomus tyrelli over a 6‐month period at four sites in two oligotrophic lakes.3. In all three taxa, seasonal variation in zooplankton C : N explained more of the variation in zooplankton δ13C than did the δ13C of POM. This suggests that variation in the lipid content of zooplankton can strongly influence temporal variation of δ13C in zooplankton.4. Using these data, we evaluate procedures that estimate the δ13C of only the non‐lipid component of zooplankton. If zooplankton lipids are primarily dietary in origin, than extracting lipids or ‘normalising’δ13C based on C : N will exclude a major dietary source, and therefore may be inappropriate.5. We conclude that temporal variation in body composition (C : N) of zooplankton can significantly influence the temporal variation of zooplankton δ13C signatures.
Comparative study of electron transport system activity and oxygen consumption of amphipods from caves and surface habitats
Authors: SIMČIČ TATJANA , LUKANČIČ SIMON , BRANCELJ ANTON 
Published: February 2005

Summary1. Respiratory electron transport system (ETS) activity and oxygen consumption were measured at 10 °C for the hypogean amphipods Niphargus stygius (from two epikarst locations) and N. krameri (from a sinking river in a cave) and the epigean amphipod Gammarus fossarum (inhabiting a spring and a river).2. ETS activity and oxygen consumption were compared between caves and the two surface locations, and between hypogean and epigean amphipods. ETS activities were found not to differ between animals from different locations, or between epigean and hypogean amphipods. As expected, the oxygen consumption of N. krameri and N. stygius was lower than that of G. fossarum.3. The high ratio between ETS activity and oxygen consumption (ETS/R ratio) showed that N. krameri and N. stygius possess high metabolic potential that can be exploited for energy recovery and rapid restoration of body reserves immediately following the appearance of favourable conditions (food and/or oxygen). In contrast, G. fossarum exhibited a low ETS/R ratio, indicating exploitation of a great proportion of the metabolic potential for standard metabolism.4. Feeding in N. stygius increased oxygen consumption but not ETS activity, and thus fed N. stygius had a much lower ETS/R ratio than starved ones.5. A relatively high metabolic potential (i.e. high ETS/R ratio) may be an adaptation to hypogean life in amphipods, in that it improves survival under poor food and/or oxygen conditions.
The 4D seismic signature of oil–water contact movement due to natural production in a stacked turbidite reservoir
Authors: MacBeth C. , Stephen K.D. , McInally A. 
Published: February 2005

ABSTRACTCombined time‐lapse reservoir simulation and seismic modelling has been performed on both 1D and 3D models of a channelized turbidite reservoir. The models have been built using core, log, laboratory and seismic data from the Nelson Field (central North Sea) as a template. Oil and water movement in the main channels, channel margins and interchannel regions is investigated, with a particular focus being the effect of poor net‐to‐gross. The analysis confirms that saturation effects dominate the response whilst stress‐sensitivity effects play a minor role. The trough–peak signature in the seismic difference volumes formed by the sweep of the water can be continued and mapped slightly further than the channel margins. This characteristic 4D signature remains roughly intact, despite the complicated depositional architecture, and accurately delineates the area of moved fluid, but it needs additional calibration to combat the detrimental influence of the low net‐to‐gross. Signal strength is largely dependent on reservoir quality, but is also compromised by the net‐to‐gross, fluid distribution and, more critically, by the exact timing of the seismic survey. For example, a region of bypassed oil zone remains undetected as it forms early during the production. This work demonstrates that to understand fully the 4D signature at a quantitative level requires adequate knowledge of the fluid properties, but also, more critically, the geology.
Improved understanding of velocity–saturation relationships using 4D computer‐tomography acoustic measurements
Authors: Monsen K. , Johnstad S.E. 
Published: February 2005

ABSTRACTA recently developed laboratory method allows for simultaneous imaging of fluid distribution and measurements of acoustic‐wave velocities during flooding experiments. Using a specially developed acoustic sample holder that combines high pressure capacity with good transparency for X‐rays, it becomes possible to investigate relationships between velocity and fluid saturation at reservoir stress levels. High‐resolution 3D images can be constructed from thin slices of cross‐sectional computer‐tomography scans (CT scans) covering the entire rock‐core volume, and from imaging the distribution of fluid at different saturation levels. The X‐ray imaging clearly adds a new dimension to rock‐physics measurements; it can be used in the explanation of variations in measured velocities from core‐scale heterogeneities. Computer tomography gives a detailed visualization of density regimes in reservoir rocks within a core. This allows an examination of the interior of core samples, revealing inhomogeneities, porosity and fluid distribution. This mapping will not only lead to an explanation of acoustic‐velocity measurements; it may also contribute to an increased understanding of the fluid‐flow process and gas/liquid mixing mechanisms in rock. Immiscible and miscible flow in core plugs can be mapped simultaneously with acoustic measurements. The effects of core heterogeneity and experimentally introduced effects can be separated, to clarify the validity of measured velocity relationships.
Seismic preprocessing and amplitude cross‐calibration for a time‐lapse amplitude study on seismic data from the Oseberg reservoir
Authors: Stucchi E. , Mazzotti A. , Ciuffi S. 
Published: February 2005

ABSTRACTThe cross‐calibration of different vintage data is an important prerequisite in attempting to determine the time‐lapse seismic effects induced by hydrocarbon production in a reservoir. This paper reports the preprocessing and cross‐calibration procedures adopted to modify the data of four seismic vintages (1982, 1989, 1992 and 1999) from the Oseberg field in the North Sea, for optimal conditions for a time‐lapse seismic amplitude analysis. The final results, in terms of time‐lapse variations, of acoustic impedance and of amplitude‐versus‐offset, are illustrated for selected data sets. The application of preprocessing to each individual vintage data set reduces the effects of the different acquisition and noise conditions, and leads to consistency in the amplitude response of the four vintages. This consistency facilitates the final amplitude cross‐calibration that is carried out using, as reference, the Cretaceous horizon reflections above the Brent reservoir. Such cross‐calibration can be considered as vintage‐consistent residual amplitude correction.Acoustic impedance sections, intercept and gradient amplitude‐versus‐offset attributes and coherent amplitude‐versus‐offset estimates are computed on the final cross‐calibrated data. The results, shown for three spatially coincident 2D lines selected from the 1982, 1989 and 1999 data sets, clearly indicate gas‐cap expansion resulting from oil production. Such expansion is manifested as a decrease in acoustic impedance and a modification of the amplitude‐versus‐offset trends in the apical part of the reservoir.
Modelling of the drying of eggplants in thin‐layers
Authors: Akpinar Ebru Kavak , Bicer Yasar 
Published: February 2005

SummaryIn this paper, the thin‐layer drying behaviour of eggplant slices (6 mm thick layers) in a convective‐type cyclone dryer is reported. Thin‐layer drying experiments were conducted at drying air temperatures of 55, 65 and 75 °C and dry air velocities of 1 and 1.5 ms−1. Data on sample mass, temperature and velocity of the dry air were recorded continuously during each test. In order to estimate and select a suitable form of the drying curve, eight different semi‐theoretical and/or empirical models were fitted to the experimental data and comparisons made of their coefficients of determination as predicted by non‐linear regression analysis. The Page model best described the drying curve of eggplant, with a correlation coefficient, r = 0.9999.
Microwave finish drying of (tapioca) starch pearls
Authors: Fu Yi‐Chung , Dai Li , Yang Binghuei B. 
Published: February 2005

SummaryStarch pearls are extremely sensitive to the rate of drying. Fast drying leads to poor quality of final cooked (rehydrated) products. The objectives of this study were to reduce the lengthy drying time by incorporating low‐power microwave finish drying and to evaluate the rehydrated quality of starch pearls. The effects of temperature and relative humidity on the drying rates of starch pearls in the constant‐rate period were determined. When evaluating the saving of time, microwave energy efficiency and rehydration quality, the best results were obtained when combined natural convection and microwave finish drying were carried out at low power levels (119–143 W). Microwave finish drying reduced the natural convective drying time by about 50–75%, with an improvement in quality, as indicated by higher unbroken ratio, less cooking loss and shorter cooking time.
A preliminary comparison of polybrominated diphenyl ether concentrations relative to lipid content and to levels of dioxins and dioxin‐like polychlorinated biphenyls in Norwegian farmed Atlantic salmon (Salmo salar)
Authors: Bethune Claudette , Julshamn Kåre , Lundebye Anne‐Katrine 
Published: February 2005

SummaryPolybrominated diphenyl ethers (PBDEs) are environmental contaminants structurally similar to polychlorinated biphenyls (PCBs), and correlations between PBDE concentrations and concentrations of lipid, PCBs, dioxins and furans in feed and farmed Atlantic salmon filet indicate PBDEs may be derived from similar sources. PBDE concentrations (3.9 ± 0.6 ng g−1 wet wt) in farmed Atlantic salmon correlated well with lipid content and these other halogenated contaminants, however, lower concentrations of PBDEs (1.6 ± 0.3 ng g−1 wet wt) showed no correlation. Possible explanations for the non‐linear behaviour of PBDE concentrations in Atlantic salmon are discussed.
The moisture dependent physical and mechanical properties of whole lentil pulse and split cotyledon
Authors: Bhattacharya Sila , Narasimha Hampapura V. , Bhattacharya Suvendu 
Published: February 2005

SummarySome physical and mechanical properties of lentil whole grain/pulse and dhal (dehusked split pulse), at different moisture contents were determined. Among the physical properties, size, sphericity, roundness, average surface area, bulk density and void fraction were determined. Bulk densities of whole pulse were between 785 and 831 kg m−3, whereas for dhal they were between 741 and 840 kg m−3 and bulk density decreased as moisture content was increased for both the whole grain and the dhal. The compression behaviour was judged by determining the firmness and the linear elastic limit, of which the former decreased with moisture content but the linear elastic limit increased. A method is proposed to calculate the total surface area of dhal and whole pulse. Photomicrographs showed the thickness of the outer seed coat to be between 25 and 65 microns.
Water activity of multicomponent mixture of solutes and non‐solutes
Authors: Caurie Matthew 
Published: February 2005

SummaryAn equation has been derived to calculate the water activity (Aw) of multicomponent mixtures of solutes and non‐solutes. The equation is based on a previous Caurie adsorption equation and it depends on the number of component ingredients and the initial moisture contents of the ingredients in the mixture. Solute and non‐solute/water interaction effects in solution were identified as playing important roles in determining accurate equilibrium Aws of the aqueous mixtures. The new equation allows for interaction effects in mixed solution/suspensions and has been tested on model foods (the data was taken from the literature) containing up to five solutes and non‐solute components. The equation displays a high degree of accuracy. Unlike the Ross equation, which applies only approximately to mixtures of dilute solutions, the new equation applies to mixtures at all solution concentrations and to wet solids.
Fever management: paediatric nurses’ knowledge, attitudes and influencing factors
Authors: Walsh Anne M. , Edwards Helen E. , Courtney Mary D. , Wilson Jenny E. , Monaghan Sarah J. 
Published: February 2005

Aims.  This paper describes Australian paediatric nurses’ knowledge of and attitudes toward fever and its management and the predictors of their intentions to administer paracetamol to a febrile child.Background.  Despite evidence‐based support for the beneficial effects of fever over the past three decades, health professionals’ negative attitudes toward fever and their reliance on antipyretics to reduce it have persisted and continue to be reported in the literature.Methods.  A self‐report questionnaire was used. An instrument was developed, piloted by test–retest and revised prior to data collection. Fifty‐one paediatric nurses working in medical wards of a metropolitan paediatric hospital in Australia participated.Results.  Nurses’ mean knowledge score about the physiology of fever, general fever management and antipyretics was 62%, which was not as high as expected. Participants reported positive attitudes toward the benefits of fever, the necessity for its reduction in children with pre‐existing cardiac or respiratory conditions and towards regular antipyretic administration masking the infective process. Negative attitudes included disbelief that temperature is often unrelated to illness severity. Conflicting attitudes toward febrile convulsions were highlighted by beliefs that antipyretic therapy prevents these and that antipyretics do not prevent initial febrile convulsions. Predictors of intentions to administer paracetamol were beliefs about the effectiveness of paracetamol and nurses’ beliefs about the expectations of others in relation to paracetamol administration. Nurses reported strong intentions to administer paracetamol to the next febrile child they cared for. Limitations of the study include the use of a nurse manager for recruitment and collecting the data at only one site.Conclusions.  Fever management is an integral aspect of paediatric nursing. For its consistent rational management, nurses must have appropriate knowledge and positive attitudes. This highlights the need for continuing education in fever management.
Patients’ evaluations of the quality of care: influencing factors and the importance of engagement
Authors: Staniszewska Sophie H. , Henderson Lorna 
Published: February 2005

Aims.  This paper reports a study exploring the process of patient evaluation and identifying the factors which influence this.Background.  Patient experiences of health care have become a central focus for researchers, policymakers, clinicians and patient groups in many countries. While surveys of patient experiences have become increasingly common internationally, concerns about the validity of concepts such as satisfaction have cast doubt on the utility of their findings. These concerns reflect our limited understanding of patient evaluation and the factors that can influence this process.Methods.  A qualitative design was adopted, using semi‐structured interviews with a sample of outpatients in their homes in one county in England. In total, 41 patients participated in the study and were interviewed before their appointment. Of these patients, 37 were interviewed again after their appointment. Six of the latter were then re‐interviewed 6 weeks after the appointment to explore whether evaluations had changed.Findings.  Patient evaluation was influenced by a number of factors, including gratitude, faith, loyalty, luck and equity. The overall effect was to prompt positive evaluation, even when care was poor. These factors should be accounted for in the interpretation of patient experiences surveys. Patient experiences were further influenced by their sense of engagement with the system. A negative sense of engagement could have a major impact on the patient, resulting in disappointment or fear and a desire to leave the health care system, and in a negative evaluation of a specific aspect of care.Conclusions.  Engagement may provide a more appropriate indicator of negative experience than dissatisfaction. The influence of these factors should be considered in future attempts to develop more sensitive and appropriate methods of eliciting patient experiences.