bluuebunny/crossref_metadata_2025_split huggingface dataset:
Direct and interactive effects of allochthonous dissolved organic matter, inorganic nutrients, and ultraviolet radiation on an alpine littoral food web
Authors: Vinebrooke Rolf D. , Leavitt Peter R. 
Published: May 2010

Allochthonous dissolved organic matter (DOM) may regulate littoral food webs by both modifying nutrient availability and attenuating potentially damaging ultraviolet radiation (UVR). These hypotheses were tested in a three‐factor (DOM, inorganic nutrients, and UVR) experiment using 24 littoral enclosures in an alpine lake located in Banff National Park, Canada. DOM was extracted from treeline soils and added (3 mg DOM liter−1) to +DOM enclosures over 1 month. These amendments were intended to simulate increases in allochthonous inputs that might occur as climate warming promotes the development of treeline soils and vegetation.DOM amendments significantly increased epilithon biomass (as total chlorophyll, carotenoids) but did not affect the abundance of either epipelon or phytoplankton. In addition, natural UV irradiance significantly enhanced the positive effect of DOM on epilithon and directly increased the abundance of epipelon. Threefold amendments of ambient nitrogen (N) and phosphorus (P) (20 N:1 P, by weight) significantly increased epilithon abundance. The positive effects of DOM, NP, and UVR on phytobenthos were primarily attributable to the increased abundance of diatoms, whereas NP affected phytoplankton by increasing chrysophytes and dinoflagellates. DOM amendments did not significantly affect the final abundances of heterotrophic bacteria and protists but did result in significantly higher densities of omnivorous copepod nauplii. These results show that allochthonous DOM is an important resource for littoral food webs in oligotrophic lakes; however, its effects are mediated by UVR and differ between benthic and planktonic habitats. Our findings suggest that littoral food‐web structure in clear, shallow lakes and ponds is altered by fluctuations in allochthonous inputs and UVR exposure arising from droughts and long‐term climatic change
Restoration of the food web of an alpine lake following fish stocking
Authors: McNaught A. S. , Schindler D. W. , Parker B. R. , Paul A. J. , Anderson R. S. , Donald D. B. , Agbeti M. 
Published: May 2010

Trout stocking in the mid‐1960s eliminated the calanoid copepod Hesperodiaptomus arcticus and other large‐bodied crustaceans such as Gammarus lacustris, Daphnia middendorffiana, and Daphnia pulex from many alpine lakes in the Rocky Mountain Parks of Canada. H. arcticus frequently dominates the plankton communities of fishless lakes, preying on rotifers and nauplius larvae. Following the extirpation of H. arcticus, rotifers and small‐bodied cyclopoid copepods dominate the zooplankton assemblages of alpine lakes.We studied the zooplankton community of Snowflake Lake, Banff National Park, from 1966 to 1995. H. arcticus was eliminated following stocking of the lake with trout in the 1960s. It failed to become reestablished after the disappearance of the fish population in the mid‐1980s. Several species of rotifers and small‐bodied crustaceans, species originally rare or absent from the plankton, became abundant following fish stocking and remained so after the fish population declined.In 1992, we reintroduced H. arcticus to Snowflake Lake. The H. arcticus population grew exponentially for 4 yr, but had not reached stable densities typical of unmanipulated alpine lakes by 1995. By 1994, however, even the small population of Hesperodiaptomus was beginning to suppress populations of rotifers, copepod nauplii, and large diatoms. Because H. arcticus is omnivorous, a simple model of cascading trophic interactions did not predict the outcome of trophic manipulations in this alpine lake.
Chemical tracing of salinity sources in Lake Kinneret (Sea of Galilee), Israel
Authors: Kolodny Yehoshua , Katz Amitai , Starinsky Abraham , Moise Tamar , Simon Ehud 
Published: May 2010

Lake Kinneret is a freshwater lake in northern Israel that receives a major part of its salt input from unmonitored springs that discharge through the lake's bottom. We attempt to characterize the nature of these springs by estimating their chemical composition. While the springs around Lake Kinneret are subject to wide spatial and temporal variations in their ionic concentrations, specific sodium (Na), potassium, magnesium (Mg), strontium, bromine, and lithium to chlorine (Cl) ion ratios are almost constant within individual springs and spring groups. The radium : Cl ratio and the δ18O‐Cl relationship confirm the notion that the spring waters result from recent mixing between saline brines and freshwater.Available compositional data from past years along with new analyses of the lake and its known springs allow identification of the salinity source that causes the observed deficit in the lake's salt budget (e.g., 91–93% chloride). The relative contributions from these saline springs are different for different ions; this contribution is highest for bromide (95%), decreases to 84% for Na, and is less than 50% for Mg.Two independent approaches have been used for balancing the salts in the lake, and they are as follows: (1) an annual mass balance between salt removal and supply of the different ions, assuming a steady‐state lake; and (2) simulation of the lake's evolution from 1964 (the beginning of salt removal from the lake via the Salinity Diversion Channel) until the present. Both methods predict very similar ionic ratios for the (yet unknown) average saline spring(s), testifying to the reliability of both approaches. The ionic ratios so obtained closely resemble Fuliya (± Tabgha)‐type waters, excluding the Tiberias and eastern shore springs as significant salt sources. This inferred composition of the average unmonitored springs depends strongly on present‐day diversion of saline springs (this diversion thus prevents their flow into the lake). The different ionic ratios that identify the various spring groups reflect the respective compositions of the brine pockets that feed them. Our simulation also shows that the layered structure of Lake Kinneret enhanced the evolution rate of the lake after the implementation of the salt diversion program in 1964.
Interactive effects of flow speed and particle concentration on growth rates of an active suspension feeder
Authors: Genovese Salvatore J. , Witman Jon D. 
Published: May 2010

Suspension‐feeding organisms dominate subtidal habitats in the Gulf of Maine (GOM) at depths of 25–40 m. Parasmittina jeffreysi is an encrusting cheilostome bryozoan found in this zone throughout the GOM. Regional variation between coastal and offshore locations in both flow speed and particle concentration makes the GOM an ideal location to study the effect of these factors on the growth of P. jeffreysi. Particle flux measurements at two offshore and two coastal sites indicated that flow speeds were >3‐fold greater offshore than at coastal sites. Chlorophyll a concentrations and particulate quantity and quality were greater at offshore sites, but sedimentation rates were greater in the coastal region. The growth rate of P. jeffreysi was measured at each of the sites using unob‐structed colonies free from spatial competition and colonies that remained within their natural community.Both unobstructed colonies and those in quadrats within the natural community displayed no regional difference in growth rates, despite higher particle flux in the offshore region. The interactive effects of flow speed and particle concentration are acting upon growth rates in opposite directions, resulting in the net effect of no regional differences in growth. Growth of unobstructed colonies at one of the coastal sites (Halfway Rock) was less than that at any of the other three sites and may have resulted from the combination of high sedimentation and extremely low flow at this site.A comparison between unobstructed colonies and those in natural quadrats suggested that growth was limited by spatial competition in the natural community. A significant site interaction effect indicates that this response did not occur at all four sites and was absent at Halfway Rock because of poor growth of unobstructed colonies. Any differences in growth due strictly to differential food acquisition (e.g., unobstructed colonies) appear to be dampened by competitive interactions in the natural community.
Decomposition dynamics of six salt marsh halophytes as determined by cupric oxide oxidation and direct temperature‐resolved mass spectrometry
Authors: Klap Vincent A. , Louchouarn Patrick , Boon Jaap J. , Hemminga Marten A. , van Soelen Jos 
Published: May 2010

This paper presents the results of a comparative study on the aerobic decomposition of six salt marsh plant species over a period of 2 yr. In addition to ash‐free dry weight (AFDW) determination and elemental analysis (C and N), two analytic methods have been applied to obtain insight into the decomposition dynamics of lignin in the various plant tissues. The analytic methods are (1) cupric oxide (CuO) oxidation followed by gas chromatography—mass spectrometry (GC‐MS) and (2) direct temperature‐resolved mass spectrometry (DT‐MS).AFDW losses could generally be well described by double exponential relations with time. Carbon‐to‐nitrogen ratios increased during the initial stages of decomposition and decreased again afterward. For five of the six plant species, a correlation between initial lignin content and AFDW loss was observed. Decay dynamics of lignin denoted a rapid relative increase during the first weeks of field exposure, followed by stabilizing contents over the next 2 yr. CuO oxidation data indicate the establishment of a stable “lignin endmember” within 1–2 months. DT‐MS data, on the contrary, showed continuous modification of the lignin polymer throughout the duration of the experiment.Evidence was found for the incorporation of (presumably) microbial N‐acetylglucosamine in the complex residue produced upon decomposition. Combination of CuO oxidation and DT‐MS data suggested that lignin degradation products became attached to the original macromolecular material and could still be identified as lignin‐derived material. The data support a humification mechanism via condensation of small degradation products instead of the selective preservation of certain biomacromolecules (like lignin).
A comparison of chlorophyll/nutrient dynamics at two survey sites near South Georgia, and the potential role of planktonic nitrogen recycled by land‐based predators
Authors: Whitehouse M. J. , Priddle J. , Brandon M. A. , Swanson C. 
Published: May 2010

There is an apparent mismatch between the high carbon demand of seals and seabirds breeding on the subantarctic island of South Georgia and the overall low primary production measured in the waters that surround the island. However, average phytoplankton production values may not be completely representative, and local systems may exist where primary production is considerably higher. Here, we examine the distribution of phytoplankton and nutrients along with physical oceanographic variables measured during two mesoscale surveys of two sites adjacent to South Georgia (January 1996 and December 1996–January 1997). Chlorophyll a concentrations were consistently higher (by up to an order of magnitude during one cruise) at the western end of the island (maximum >30 mg m−3). Surface phosphate and silicate at times appeared to have been depleted to particularly low levels (<0.8 and <2 mmol m−3, respectively), whereas nitrate concentrations remained relatively high throughout the two surveys (∼14–30 mmol m−3). However, ammonium, a crucial reduced nitrogen source for South Georgia phytoplankton, was plentiful and widespread in the upper mixed layer during both surveys (maximum >3 mmol m−3). An examination of upper mixed layer nutrient dynamics showed an apparent shortfall in phytoplankton use of nitrate‐nitrogen compared with silicate and phosphate at the western end of the island, where ammonium‐nitrogen use appeared greatest.The western end of subantarctic island of South Georgia is noted for its large numbers of breeding Antarctic fur
seals, Arctocephalus gazella, and macaroni penguins, Eudyptes chrysolophus, (∼2.6 × 106 and ∼5.4 × 106 individuals, respectively). As land‐breeding endotherms, these animals have high metabolic costs, and they recycle dietary nitrogen rapidly. Furthermore, because they take krill advected into their foraging range and return frequently to their colonies to feed pups and chicks, they concentrate nutrients close to the land. We evaluated the relationship between the preferential use of reduced nitrogen by phytoplankton and its production and concentration by the landbased predators (a minimum of 1 × 107 mol N d−1 in January for the colonies in the study area). We examined the predators’ potential for the redistribution of plankton nitrogen in an on‐shelf environment where currents were relatively sluggish and encompassed retentive, eddy‐like structures, which might have facilitated more stable conditions for phytoplankton growth.
Dissolved organic phosphorus in the coastal ocean: Reassessment of available methods and seasonal phosphorus profiles from the Eel River Shelf
Authors: Monaghan E. J. , Ruttenberg K. C. 
Published: May 2010

Methods for quantifying total dissolved phosphorus (TDP) were reevaluated. High‐temperature ashing/hydrolysis (Ash/Hydrol.) and Acid Persulfate methods were examined for their ability to quantitatively convert a range of organic‐P compounds to orthophosphate. The Ash/Hydrol. method recovered on average 99% of organic‐P compounds tested, including phosphonates (compounds with C‐P bonds). Contrary to concerns voiced in prior studies, we found no P loss due to volatilization in seawater samples. Poor recovery by the Acid Persulfate method was observed for two compound classes: phosphonates and phospholipids. The Ash/Hydrol. method is recommended for routine TDP analyses.The hydrolysis of dissolved organic phosphorus (DOP) during the phosphomolybdate‐blue reaction and the subsequent overestimation of dissolved inorganic phosphorus (DIP) have long been a concern. Extent of hydrolysis of standard DOP compounds was evaluated both during this reaction and over long‐term acidified (pH 1.0)/refrigerated and unacidified/frozen storage. Eleven of 12 compounds tested hydrolyzed <2% during the phosphomolybdate‐blue reaction. Phospholipid, phosphosugar, and nucleotide mono‐ and diphosphate standards stored acidified/refrigerated over 2.5 months were <5% hydrolyzed; compounds with higher energy phosphate bonds (e.g., phosphocreatine) hydrolyzed to a greater extent. A natural seawater sample showed no hydrolysis over 80 d, however, suggesting that refrigerated storage of acidified samples is a viable option.Seasonal DOP profiles from the Eel River Shelf quantified by the Ash/Hydrol. and Acid Persulfate methods yielded comparable results, indicating that the DOP pool at this site did not contain significant phospholipids or phosphonates, which are underrecovered by the Persulfate method. Recoveries using a third method, Nitrate Oxidation, were on average 7% lower. Surface‐water DOP exceeded DIP in summer and was apparently related to biological productivity, underscoring the need to include organic species when evaluating nutrient limitation and creating nutrient budgets.
Growth dynamic of ewes’ lump cheese microflora
Authors: Medveďová Alžbeta , Valí­k Ľubomí­r , Liptáková Denisa , Hudecová Anna 
Published: May 2010

The preparation of ewes’ lump cheese has been known in Slovakia for a long time. It is made from raw or pasteurized ewes’ milk, especially due to the activity of lactic acid bacteria. The encouragement of the acidification process by the starters is profitable to use with the respect to the quality of the product. In our study we focused on the growth analysis of Staphylococcus aureus and Escherichia coli in ewes’ cheeses prepared in laboratory conditions with or without addition of starter culture from raw or heat treated milk. According to our experimental data, the addition of the lactic acid bacteria culture and the following pH decrease on the levels lower than 5.0 for 1 to 2 days were able to inhibit the growth of S. aureus and E. coli on concentrations lower than 104 CFU/g required by European Union legislation. The growth data found in this work may provide the information for food technologists and microbiologists to get the studied organisms under the control.
Close‐to‐streamline numerical study on gas velocity distribution in industrial scale electrostatic precipitator gas inlet hood
Authors: Zhang Jie 
Published: May 2010

AbstractThe uniformity of gas velocity distribution in gas inlet hoods is important to guarantee high dedust efficiency in electrostatic precipitators (ESPs), especially for high solid concentration applications. The close‐to‐streamline numerical method was developed to geometrically 1:1 simulate an industrial scale ESP gas inlet hood, which had complicated internal structures, such as dedust angle irons and gas distribution perforated plates with up to 10 000 holes. The realizable k‐ε model was used for the gas flow simulation. The numerical results of the gas velocity distribution show reasonable agreement with the field measurements. The outlet gas velocity distribution was non‐uniform, which was lower in the central region and higher in the near‐wall regions. The gas flow characteristics were analysed to reveal the main influence factors on gas velocity distribution and put forward corresponding modification methods. After the retrofit, the field measurements of the outlet gas velocities showed that the gas velocity distribution improved. The non‐uniform index of outlet gas velocity distribution decreased greatly from 0.355 to 0.244. The visible dust emissions from the chimney disappeared which indicated increased dedust efficiency. Therefore, the close‐to‐streamline method can simulate gas velocity distribution in complicated structures of ESP gas inlet hoods. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
Effect of polymer–surfactant structure on its solution viscosity
Authors: Badoga Sandeep , Pattanayek Sudip K. , Kumar Anil , Pandey Lalit Mohan 
Published: May 2010

AbstractPolymer–surfactant interactions in solutions are important in wide range of applications. The interactions lead to the formation of various polymer–surfactant structures. The solution viscosity is dependent on the structure. Here we have studied the dependence of viscosity and structure on the composition of polymer–surfactant mixture. We have used non‐ionic polymer polyvinyl pyrrolidone (PVP) and negatively charged surfactant sodium dodecyl sulfate (SDS). PVP behaves as a negatively charged polyelectrolyte in pure water at pH 7.4. It interacts with SDS through hydrophobic interaction. This leads to the polymer saturation point (PSP). PVP behaves as a positively charged polyelectrolyte at pH 2.4. The SDS neutralizes the opposite charge of polymer. After the neutralization point of PVP, excess SDS interacts with the polymer through hydrophobic interaction. From the data of charge neutralization, charge on the polymer is calculated. From the data of PSP on PVP at various concentrations, we calculated the number of SDS molecules per PVP molecule. The structure of PVP–SDS complexes is observed by using transmission electron microscope at room temperature. The viscosity data are explained from the observed structure of PVP–SDS mixture. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
Weighted local shape blending for facial motion retargetting
Authors: Na Kyung‐Gun , Jung Moon‐Ryul 
Published: May 2010

AbstractWe present a system that maps a sparse configuration of facial markers captured from an actor on to target meshes, by blending highly detailed target key meshes. One way of determining the blending weights is local shape blending which segments a facial mesh into disjoint regions, and tries to represent each region on the facial mesh as a weighted sum of the corresponding regions on the key meshes. This has the side effect of decoupling the natural correlation between different parts of a face. This problem has been improved by a recent method which considers the entire face as the sum of overlapping soft regions centered at each control point, where the influence of the control‐points are reduced with distance. But it goes too far in the opposite direction: by treating control points independently and thereby ignoring the spatial coherence among nearby control points on a face, it can cause unwanted interferences between the nearby control‐points (i.e. between the associated soft regions). To avoid both problems, we retain the basic framework of local shape blending, but consider nearby control points together by treating them as a weighted region with a weighting function defined over it. Copyright © 2010 John Wiley & Sons, Ltd.
A sketch interface to empower novices to create 3D animations
Authors: Jeon Jaewoong , Jang Hyunho , Lim Soon‐Bum , Choy Yoon‐Chul 
Published: May 2010

AbstractWe introduce a multiple‐pass sketch‐based user interface, designed for novice users, which avoids spatial ambiguities and hence allows considerable freedom in creating 3D animations. The user first draws the path along which a character or object is to move. A vertical motion window is then erected along this path, on which the user specifies the character's gestures or the object's vertical movements. A further cross‐motion window can be used to add detail to the movements of the object. Window‐specific camera modules present the user with appropriate views, extending the fluidity of pencil and paper to 3D. A usability study involving 60 users, who were previously unfamiliar with 3D animation tools, demonstrated that the proposed interface is easy to learn and effective in use. Copyright © 2010 John Wiley & Sons, Ltd.
Stable stylized wireframe rendering
Authors: Tang Chen , Li Sheng , Wang Guoping , Zang Yutong 
Published: May 2010

AbstractStylized wireframe rendering of 3D model is widely used in animation software in order to depict the configuration of deformable model in comprehensible ways. However, since some inherent flaws in traditional depth test based rendering technology, shape of lines can not been preserved as continuous movement or deformation of models. There often exists severe aliasing like flickering artifact when objects rendered in line form animate, especially rendered with thick or dashed line. To cover this artifact, unlike traditional approach, we propose a novel fast line drawing method with high visual fidelity for wireframe depiction which only depends on intrinsic topology of primitives without any preprocessing step or extra adjacent information pre‐stored. In contrast to previous widely‐used solutions, our method is advantageous in highly accurate visibility, clear and stable line appearance without flickering even for thick and dashed lines with uniform width and steady configuration as model moves or animates, so that it is strongly suitable for animation system. In addition, our approach can be easily implemented and controlled without any additional preestimate parameters supplied by users. Copyright © 2010 John Wiley & Sons, Ltd.
Real‐time hybrid solid simulation: spectral unification of deformable and rigid materials
Authors: Yang Yin , Rong Guodong , Torres Luis , Guo Xiaohu 
Published: May 2010

AbstractA novel framework is proposed in this paper to simulate hybrid solids with deformable and rigid materials in real‐time. Both types of materials are uniformly integrated into one spectral simulator. Based on the modal warping technique, we employ a new constraint strategy which eliminates the accumulation of approximation errors at the boundary interfaces, thus naturally gluing different materials. We also utilize the GPU to accelerate the run‐time computation when updating the geometry of the hybrid solid—the most expensive step in this framework. This work provides a general‐purpose solution of simulating hybrid objects in real‐time, even for large‐scale models. Copyright © 2010 John Wiley & Sons, Ltd.