bluuebunny/crossref_metadata_2025 huggingface dataset:
Porcelainized stoneware: architectural, processing and physico-mechanical properties
Authors: Manfredini T. , Romagnoli M. , Rincón J. María
Published: November 2010

Porcelainized stoneware is an extremely hard and homogeneous unglazed ceramic material obtained by fastfiring of kaolinitic ceramic bodies containing a large amount of fluxes. The obtained tiles, available in a large variety of colours, shape size and surface finish, are characterized by very low porosity (<0,3wt% expressed as water absorption) and are ideal for heavy-traffic areas subject to mechanical and chemical stresses. Porcelainized stoneware tiles offer alternative valid (and in many cases necessary) solutions to the traditional glazed tiles either for interiors or for exteriors both in modern or classic constructions for flooring and covering.
The use of vulcanic glasses in cellular concrete
Authors: Alvarez J. L. , Vega N.
Published: November 2010

This paper covers studies made using different mixes for cellular concrete variating silica sand, vulcanic glass and aluminium powder contents.
Studies on compressive strenght, dry density and X-ray diffraction are performed on autoclave cured cellular concrete, concluding that best results are attained when vulcanic glass contents reaches 50% of silica sand.
When percentage of aluminium powder is diminished from 0.11% to 0.09%, alight increase in density, with noticiable growth of comprensive strength are observed.
A multiparametric method of interpolation using WOA05 applied to anthropogenic CO2 in the Atlantic
Authors: Velo Anton , Vázquez-Rodríguez Marcos , Padín Xose A. , Gilcoto Miguel , Ríos Aída F. , Pérez Fiz F.
Published: November 2010

This paper describes the development of a multiparametric interpolation method and its application to anthropogenic carbon (CANT) in the Atlantic, calculated by two estimation methods using the CARINA database. The multiparametric interpolation proposed uses potential temperature (θ), salinity, conservative ‘NO’ and ‘PO’ as conservative parameters for the gridding, and the World Ocean Atlas (WOA05) as a reference for the grid structure and the indicated parameters. We thus complement CARINA data with WOA05 database in an attempt to obtain better gridded values by keeping the physical-biogeochemical sea structures. The algorithms developed here also have the prerequisite of being simple and easy to implement. To test the improvements achieved, a comparison between the proposed multiparametric method and a pure spatial interpolation for an independent parameter (O2) was made. As an application case study, CANT estimations by two methods (φCTº and TrOCA) were performed on the CARINA database and then gridded by both interpolation methods (spatial and multiparametric). Finally, a calculation of CANT inventories for the whole Atlantic Ocean was performed with the gridded values and using ETOPO2v2 as the sea bottom. Thus, the inventories were between 55.1 and 55.2 Pg-C with the φCTº method and between 57.9 and 57.6 Pg-C with the TrOCA method.
Carbonate system distribution south of the Canary Islands in spring 2000
Authors: Ucha Iván R. , González-Dávila Melchor , Santana-Casiano Magdalena , Rueda María José , Llinás Octavio
Published: November 2010

The measurement of the surface molar fraction of CO2 (atmosphere and sea water) and water column pHT, total alkalinity, AT, nutrients and oxygen were carried out in spring 2000 at the European Station for Time Series in the Ocean at the Canary Islands (ESTOC) and in the area located south of the Canary Islands. The significant eddy field strongly affecting the pattern of the chemical and carbonate system variables is presented and discussed. A mixing model based on the thermohaline properties of the water masses was established. The model explained over 97% of the variability found in the distribution of the chemical variables. Intermediate waters to the south of the Canary Islands show a high contribution of Antarctic waters with about 5% of pure Antarctic Intermediate Water. Moreover, the surface structure affected the atmosphere-ocean carbon dioxide exchange, making the area act as a CO2 sink taking up 9.1 mmol m-2 week-1, corresponding to 0.03 Mt of CO2 which were taken up by the area in a week at the end of March 2000.
Sediment geochemistry and accumulation rates on the northeastern shelf of the Gulf of Cádiz (SW Iberian Peninsula)
Authors: Guerra Roberta , Dinelli Enrico , Righi Serena , Forja Jesús M. , García-Luque Enrique
Published: November 2010

Geochemistry, total organic carbon and total nitrogen of three sediment cores collected in the Gulf of Cádiz and the Guadalquivir prodelta areas in Spain were investigated. The C/N ratio, mostly around 10, seems to indicate a predominantly marine origin for the sedimentary organic matter. Major and minor elements (Si, Ti, Al, Fe, Mg, Ca, K, Na, P, S) and trace elements (Mn, Sc, V, Cr, Ni, Cu, Zn, Rb, Sr, Y, Zr, Ba, Ce, Pb, Hg) showed significant differences in bulk chemical composition between the two areas. Despite the effects of bioturbation, vertical changes in downcore profiles of heavy metals occur only in the cores of the Cádiz area, although the concentrations keep to low levels. The relatively high concentrations of Zr and Y, elements commonly associated with the heavy minerals fraction, at the top of cores from the Cádiz area are attributed to an enrichment of heavy minerals related to selective transport that concentrates this fraction. 137Cs and 210Pb activities in one of the two sediment cores collected in the Gulf of Cádiz were also measured. The distribution of excess 210Pb was used to determine the modern (last 100 yr) mass accumulation rate and the depth of sediment mixing on the continental shelf of the gulf. Estimated sediment accumulation rate was 0.1 g cm-2 yr-1. The uppermost 4 cm had uniform excess 210Pb activity profiles above a region of steadily decreasing 210Pb activity, and this phenomenon was attributed to sediment mixing (bioturbation). 137Cs activity was lower than 3 Bq kg-1 and the profile does not show evidence of fallout peaks.
Echinoderes rex n. sp. (Kinorhyncha: Cyclorhagida), the largest Echinoderes species found so far
Authors: Lundbye Henriette , Soo Rho Hyun , Vinther Sørensen Martin
Published: November 2010

A new kinorhynch species, Echinoderes rex n. sp., is described from the Korea Strait. The new species is characterized by a pair of diminutive lateral terminal spines (19-23 μm) and a trunk length of 482-528 μm, making it the largest Echinoderes described so far. Unique for the new species is also the presence of a type of putative glandular cell outlets that have not been described previously. This paper presents light and scanning electron micrographs of the new structure. In addition, E. rex n. sp. is characterized by having a single middorsal spine on segment 4, lateroventral tubules on segment 5 and 8 and lateroventral acicular spines on segments 6 and 7. A pair of distinct and conspicuously large sieve plates, only described from two other species of the genus, is present on segment 9 in E. rex n. sp. A comparison is made with other species of Echinoderes and the similarities are discussed.
Die liter�re komposisie van Josua 3:1�17
Authors: Wildenboer Johan
Published: November 2010

The literary composition of Joshua 3:1 17 Joshua 3 and 4 confront the attentive reader with several literary problems, especially with regard to chronology. This article attempts to provide a solution to the problems in Joshua 3. The author reconstructed narratives, namely a Deuteronomistic and a post-priestly narrative. The Deuteronomistic narrative forms part of the original narrative of the Jordan crossing. It also forms part of an exilic Deuteronomistic History. The aim of this exilic Deuteronomistic History is to explain the loss of the land during the Babylonian exile.The post-priestly narrative of Joshua 3 and 4 most probably came into being when the priestly material (Gen�Num) was linked with the Deuteronomistic History. Thus, the post-priestly narrative of Joshua 3 and 4 elaborates on and expands the original Deuteronomistic narrative of the Jordan crossing. The merging of these two narratives is the cause of the chronological and other literary problems in Joshua 3.
Targeted Knockdown of Tissue Factor in B16F10 Melanoma Cells suppresses their Ability to Metastasize to Bone and cause cancellous Bone Loss
Authors: Politano Amanda , Butcher Martin , Zeadin Melec , Gross Peter , Vaezzadeh Nima , Shaughnessy Stephen G.
Published: November 2010

In this study, we use a well-defined mouse model to examine tissue factor's (TF) role in osteolytic bone metastasis. C57BL/6 mice received either mock siRNA-transfected or TF-specific siRNA-transfected B16F10 melanoma cells by left ventricular injection. A third group served as an age-matched control and did not receive any tumour cells. The effect on tumour burden and bone strength was then determined 14 days later by using bone histomorphometry and biomechanical testing. Based on histomorphometric analysis of the femurs, mice receiving TF-specific siRNA-transfected tumour cells had significantly reduced tumour burden as compared to those from mice that received mock siRNA-transfected tumour cells (2.20 ± 0.58% vs. 9.18 ± 2.20%). Furthermore, the femurs from mice receiving TF siRNA-transfected tumour cells displayed decreased osteoclast surface and consequently, increased cancellous bone volume and strength when compared to those isolated from mice that were injected with mock-transfected tumour cells. More importantly, no differences in osteoclast surface or cancellous bone volume and strength were observed when the femurs of mice that received TF siRNA-transfected tumour cells were compared to control mice that did not receive tumour cells. Based on these findings, we conclude that the expression of TF by tumour cells promotes their ability to metastasize to bone, thereby facilitating tumour cell—induced cancellous bone loss.
Estimation of Hazard Functions in the Log-Linear Age-Period-Cohort Model: Application to Lung Cancer Risk Associated with Geographical Area
Authors: Mdzinarishvili Tengiz , Gleason Michael X. , Sherman Simon
Published: November 2010

An efficient computing procedure for estimating the age-specific hazard functions by the log-linear age-period-cohort (LLAPC) model is proposed. This procedure accounts for the influence of time period and birth cohort effects on the distribution of age-specific cancer incidence rates and estimates the hazard function for populations with different exposures to a given categorical risk factor. For these populations, the ratio of the corresponding age-specific hazard functions is proposed for use as a measure of relative hazard. This procedure was used for estimating the risks of lung cancer (LC) for populations living in different geographical areas. For this purpose, the LC incidence rates in white men and women, in three geographical areas (namely: San Francisco-Oakland, Connecticut and Detroit), collected from the SEER 9 database during 1975–2004, were utilized. It was found that in white men the averaged relative hazard (an average of the relative hazards over all ages) of LC in Connecticut vs. San Francisco-Oakland is 1.31 ± 0.02, while in Detroit vs. San Francisco-Oakland this averaged relative hazard is 1.53 ± 0.02. In white women, analogous hazards in Connecticut vs. San Francisco-Oakland and Detroit vs. San Francisco-Oakland are 1.22 ± 0.02 and 1.32 ± 0.02, correspondingly. The proposed computing procedure can be used for assessing hazard functions for other categorical risk factors, such as gender, race, lifestyle, diet, obesity, etc.
Optimal Network Alignment with Graphlet Degree Vectors
Authors: Milenković Tijana , Ng Weng Leong , Hayes Wayne , PržUlj NatašA
Published: November 2010

Important biological information is encoded in the topology of biological networks. Comparative analyses of biological networks are proving to be valuable, as they can lead to transfer of knowledge between species and give deeper insights into biological function, disease, and evolution. We introduce a new method that uses the Hungarian algorithm to produce optimal global alignment between two networks using any cost function. We design a cost function based solely on network topology and use it in our network alignment. Our method can be applied to any two networks, not just biological ones, since it is based only on network topology. We use our new method to align protein-protein interaction networks of two eukaryotic species and demonstrate that our alignment exposes large and topologically complex regions of network similarity. At the same time, our alignment is biologically valid, since many of the aligned protein pairs perform the same biological function. From the alignment, we predict function of yet unannotated proteins, many of which we validate in the literature. Also, we apply our method to find topological similarities between metabolic networks of different species and build phylogenetic trees based on our network alignment score. The phylogenetic trees obtained in this way bear a striking resemblance to the ones obtained by sequence alignments. Our method detects topologically similar regions in large networks that are statistically significant. It does this independent of protein sequence or any other information external to network topology.
Relationship between Selected Socio-Demographic Factors and Cancer of Oral Cavity - A Case Control Study
Authors: Madani Abdoul Hossain , Dikshit Madhurima , Bhaduri Debanshu , Jahromi Abdolreza Sotoodeh , Aghamolaei Teamur
Published: November 2010

The aim of this study was to recognize factors associated with cancer of oral cavity considering socio-demographic characteristics. The cases were 350 with squamous-cell carcinoma of oral cavity diagnosed between 2005 and 2006 in Morbai, Narandia, Budharani Cancer Institute, Pune, India. Similar number of controls match for age and sex selected from the background population. Cases and controls were interviewed for tobacco related habits and general characteristics; age, gender, education and possible socio-demographic factors. Chi-square test in uni-variate analysis and estimate for risk showed that education, occupation and monthly household income were significantly different between cases and controls ( P < 0.001). Irrespective to gender, relative risk, here odds ratio, (OR) of low level of education (OR = 5.3, CI 3.7–7.6), working in field as a farmer (OR = 2.5, CI 1.7–3.7), and monthly household income less than 5000 Indian Rupees currency (OR = 1.7, CI 1.2–2.3) were significant risk factors for oral cancer. While, there was no significant relationship between religious and or marital status either in males or females.
Article Commentary: Rough Set Soft Computing Cancer Classification and Network: One Stone, Two Birds
Authors: Zhang Yue
Published: November 2010

Gene expression profiling provides tremendous information to help unravel the complexity of cancer. The selection of the most informative genes from huge noise for cancer classification has taken centre stage, along with predicting the function of such identified genes and the construction of direct gene regulatory networks at different system levels with a tuneable parameter. A new study by Wang and Gotoh described a novel Variable Precision Rough Sets-rooted robust soft computing method to successfully address these problems and has yielded some new insights. The significance of this progress and its perspectives will be discussed in this article.
Inhibition of Antiapoptotic BCL-XL, BCL-2, and MCL-1 Proteins by Small Molecule Mimetics
Authors: Dalafave D.S. , Prisco G.
Published: November 2010

Informatics and computational design methods were used to create new molecules that could potentially bind antiapoptotic proteins, thus promoting death of cancer cells. Apoptosis is a cellular process that leads to the death of damaged cells. Its malfunction can cause cancer and poor response to conventional chemotherapy. After being activated by cellular stress signals, proapoptotic proteins bind antiapoptotic proteins, thus allowing apoptosis to go forward. An excess of antiapoptotic proteins can prevent apoptosis. Designed molecules that mimic the roles of proapoptotic proteins can promote the death of cancer cells. The goal of our study was to create new putative mimetics that could simultaneously bind several antiapoptotic proteins. Five new small molecules were designed that formed stable complexes with BCL-2, BCL-XL, and MCL-1 antiapoptotic proteins. These results are novel because, to our knowledge, there are not many, if any, small molecules known to bind all three proteins. Drug-likeness studies performed on the designed molecules, as well as previous experimental and preclinical studies on similar agents, strongly suggest that the designed molecules may indeed be promising drug candidates. All five molecules showed “drug-like” properties and had overall drug-likeness scores between 81% and 96%. A single drug based on these mimetics should cost less and cause fewer side effects than a combination of drugs each aimed at a single protein. Computer-based molecular design promises to accelerate drug research by predicting potential effectiveness of designed molecules prior to laborious experiments and costly preclinical trials.
Heterogeneity between Ducts of the Same Nuclear Grade Involved by Duct CarcinomaIn Situ(DCIS) of the Breast
Authors: Miller Naomi A. , Chapman Judith-Anne W. , Qian Jin , Christens-Barry William A. , Fu Yuejiao , Yuan Yan , Lickley H. Lavina A. , Axelrod David E.
Published: November 2010

Purpose

Nuclear grade of breast DCIS is considered during patient management decision-making although it may have only a modest prognostic association with therapeutic outcome. We hypothesized that visual inspection may miss substantive differences in nuclei classified as having the same nuclear grade. To test this hypothesis, we measured subvisual nuclear features by quantitative image cytometry for nuclei with the same grade, and tested for statistical differences in these features.

Experimental design and statistical analysis

Thirty-nine nuclear digital image features of about 100 nuclei were measured in digital images of H<E stained slides of 81 breast biopsy specimens. One field with at least 5 ducts was evaluated for each patient. We compared features of nuclei with the same grade in multiple ducts of the same patient with ANOVA (or Welch test), and compared features of nuclei with the same grade in two ducts of different patients using 2-sided t-tests ( P ≤ 0.05). Also, we compared image features for nuclei in patients with single grade to those with the same grade in patients with multiple grades using t-tests.

Results

Statistically significant differences were detected in nuclear features between ducts with the same nuclear grade, both in different ducts of the same patient, and between ducts in different patients with DCIS of more than one grade.

Conclusion

Nuclei in ducts visually described as having the same nuclear grade had significantly different subvisual digital image features. These subvisual differences may be considered additional manifestations of heterogeneity over and above differences that can be observed microscopically. This heterogeneity may explain the inconsistency of nuclear grading as a prognostic factor.
Blasted Cell Line Names
Authors: Wang Jing , Byers Lauren A. , Yordy John S. , Liu Wenbin , Shen Li , Baggerly Keith A. , Giri Uma , Myers Jeffrey N. , Ang K. Kian , Story Michael D. , Girard Luc , Minna John D. , Heymach John V. , Coombes Kevin R.
Published: November 2010

Background

While trying to integrate multiple data sets collected by different researchers, we noticed that the sample names were frequently entered inconsistently. Most of the variations appeared to involve punctuation, white space, or their absence, at the juncture between alphabetic and numeric portions of the cell line name.

Results

Reasoning that the variant names could be described in terms of mutations or deletions of character strings, we implemented a simple version of the Needleman-Wunsch global sequence alignment algorithm and applied it to the cell line names. All correct matches were found by this procedure. Incorrect matches only occured when a cell line was present in one data set but not in the other. The raw match scores tended to be substantially worse for the incorrect matches.

Conclusions

A simple application of the Needleman-Wunsch global sequence alignment algorithm provides a useful first pass at matching sample names from different data sets.
Estimating Shared Copy Number Aberrations for Array CGH Data: The Linear-Median Method
Authors: Lin Y.-X. , Baladandayuthapani V. , Bonato V. , Do K.-A.
Published: November 2010

Motivation

Existing methods for estimating copy number variations in array comparative genomic hybridization (aCGH) data are limited to estimations of the gain/loss of chromosome regions for single sample analysis. We propose the linear-median method for estimating shared copy numbers in DNA sequences across multiple samples, demonstrate its operating characteristics through simulations and applications to real cancer data, and compare it to two existing methods.

Results

Our proposed linear-median method has the power to estimate common changes that appear at isolated single probe positions or very short regions. Such changes are hard to detect by current methods. This new method shows a higher rate of true positives and a lower rate of false positives. The linear-median method is non-parametric and hence is more robust in estimating copy number. Additionally the linear-median method is easily computable for practical aCGH data sets compared to other copy number estimation methods.
Maximum Likelihood Analyses of 3,490 rbcL Sequences: Scalability of Comprehensive Inference versus Group-Specific Taxon Sampling
Authors: Stamatakis Alexandros , Göker Markus , Grimm Guido W.
Published: November 2010

The constant accumulation of sequence data poses new computational and methodological challenges for phylogenetic inference, since multiple sequence alignments grow both in the horizontal (number of base pairs, phylogenomic alignments) as well as vertical (number of taxa) dimension. Put aside the ongoing controversial discussion about appropriate models, partitioning schemes, and assembly methods for phylogenomic alignments, coupled with the high computational cost to infer these, for many organismic groups, a sufficient number of taxa is often exclusively available from one or just a few genes (e.g., rbcL, matK, rDNA). In this paper we address scalability of Maximum-Likelihood-based phylogeny reconstruction with respect to the number of taxa by example of several large nested single-gene rbcL alignments comprising 400 up to 3,491 taxa. In order to test the effect of taxon sampling, we employ an appropriately adapted taxon jackknifing approach. In contrast to standard jackknifing, this taxon subsampling procedure is not conducted entirely at random, but based on drawing subsamples from empirical taxon-groups which can either be user-defined or determined by using taxonomic information from databases. Our results indicate that, despite an unfavorable number of sequences to number of base pairs ratio, i.e., many relatively short sequences, Maximum Likelihood tree searches and bootstrap analyses scale well on single-gene rbcL alignments with a dense taxon sampling up to several thousand sequences. Moreover, the newly implemented taxon subsampling procedure can be beneficial for inferring higher level relationships and interpreting bootstrap support from comprehensive analysis.
Relative Codon Adaptation Index, a Sensitive Measure of Codon Usage Bias
Authors: Lee Soohyun , Weon Seyeon , Lee Sooncheol , Kang Changwon
Published: November 2010

We propose a simple, sensitive measure of synonymous codon usage bias, the Relative Codon Adaptation Index (rCAI), as a way to discriminate better between highly biased and unbiased regions, compared with the widely used Codon Adaptation Index (CAI). CAI is a geometric mean of the relative usage of codons in a gene, and is calculated using the codon usage table trained with a set of highly expressed genes. In contrast, rCAI is computed by subtracting the background codon usage trained with two noncoding frames of highly expressed genes from the codon usage in the coding frame. rCAI has higher signal-to-noise ratio than CAI, considering that noncoding frames would not show codon bias. Translation efficiency and protein abundance correlates comparably or better with rCAI than CAI or other measures such as ‘effective number of codons’ and ‘SCUMBLE offsets’. Within overlapping coding regions, one of the two coding frames dominates in codon usage bias according to rCAI. Presumably, rCAI could substitute CAI in diverse applications.
Molecular Phylogeny of Edge Hill Virus Supports its Position in the Yellow Fever Virus Group and Identifies a New Genetic Variant
Authors: Macdonald Joanne , Poidinger Michael , Mackenzie John S. , Russell Richard C. , Doggett Stephen , Broom Annette K. , Phillips Debra , Potamski Joseph , Gard Geoff , Whelan Peter , Weir Richard , Young Paul R. , Gendle Debra , Maher Sheryl , Barnard Ross T. , Hall Roy A.
Published: November 2010

Edge Hill virus (EHV) is a mosquito-borne flavivirus isolated throughout Australia during mosquito surveillance programs. While not posing an immediate threat to the human population, EHV is a taxonomically interesting flavivirus since it remains the only member of the yellow fever virus (YFV) sub-group to be detected within Australia. Here we present both an antigenic and genetic investigation of collected isolates, and confirm taxonomic classification of the virus within the YFV-group. Isolates were not clustered based on geographical origin or time of isolation, suggesting that minimal genetic evolution of EHV has occurred over geographic distance or time within the EHV cluster. However, two isolates showed significant differences in antigenic reactivity patterns, and had a much larger divergence from the EHV prototype (19% nucleotide and 6% amino acid divergence), indicating a distinct subtype or variant within the EHV subgroup.
A Clustering Optimization Strategy for Molecular Taxonomy Applied to Planktonic Foraminifera SSU rDNA
Authors: Göker Markus , Grimm Guido W. , Auch Alexander F. , Aurahs Ralf , Kučera Michal
Published: November 2010

Identifying species is challenging in the case of organisms for which primarily molecular data are available. Even if morphological features are available, molecular taxonomy is often necessary to revise taxonomic concepts and to analyze environmental DNA sequences. However, clustering approaches to delineate molecular operational taxonomic units often rely on arbitrary parameter choices. Also, distance calculation is difficult for highly alignment-ambiguous sequences. Here, we applied a recently described clustering optimization method to highly divergent planktonic foraminifera SSU rDNA sequences. We determined the distance function and the clustering setting that result in the highest agreement with morphological reference data. Alignment-free distance calculation, when adapted to the use with partly non-homologous sequences caused by distinct primer pairs, outperformed multiple sequence alignment. Clustering optimization offers new perspectives for the barcoding of species diversity and for environmental sequencing. It bridges the gap between traditional and modern taxonomic disciplines by specifically addressing the issue of how to optimally account for both genetic divergence and given species concepts.
State Legislative Support for Parks
Authors: Kruger Judy , Lankford Tina , schmid Tom
Published: November 2010

Background

Parks are important venues that can encourage population-level physical activity, and policy legislation can facilitate or discourage physical activity and other park uses, depending on the type and level of support. This study aims to summarize the status and content of state-level park-related legislation.

Methods

We searched for eligible legislation from 2001-2007 in two data sources, CDC's Nutrition, Physical Activity and Obesity Legislative Database and Lexis-Nexis, using the key words conservation, growth management/land use, parks, recreation, preservation, path, green space, or open space. State legislation was categorized into seven broad topic areas and analyzed by number introduced and passed (enacted as law), by state and category.

Results

States varied in the number and type of park-related legislation introduced and passed. Common categories of introduced park-related state legislation were preservation or conservation (n = 26, 9 passed), funding (n = 43, 10 passed), creation or acquisition of park land (n = 53, 9 passed), safety and liability (n = 34, 5 passed), accessibility (n = 20, 2 passed), outreach (n = 15, 2 passed), and outdoor activities (n = 13, 2 passed).

Conclusion

During 2001 to 2007, 19% of park-related state legislation was enacted. Research on legislative policy is an emerging field, and more information on the content of park-related legislation could assist states in their efforts to promote physical activity in park venues.
The trace metal composition of size‐fractionated plankton in the South China Sea: Biotic versus abiotic sources
Authors: Ho Tung-Yuan , Wen Liang-Saw , You Chen-Feng , Lee Der-Chuen
Published: November 2010

We report the elemental composition (P, Si, Al, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) in the size‐fractionated plankton and suspended particulate matter (SPM) in the surface waters of the South China Sea. The sizefractionated plankton were effectively and gently separated by gravity through a novel trace‐metal‐clean filtration device, equipped with 150‐, 60‐, and 10‐µm aperture nets in sequence to concentrate the plankton. P‐normalized metal quotas in the largest fraction, mostly composed of copepods, were close to or slightly lower than the average metal quotas obtained from previous field studies. However, the total metal quotas in the two smaller fractions were 8‐ to 40‐fold higher than the largest one, and they increased with decreasing sizes. The striking correlation between some essential metals and chlorophyll (Chl) in the SPM at the offshore site indicates that the majority of the metals were associated with algae. Nevertheless, the P‐normalized metal quotas also showed positive correlations with abiogenic Al and Mn, indicating that most of the metals associated with phytoplankton were from extracellular inorganic particles. Preliminary evidence suggests that the extracellular metals were originally derived from anthropogenic aerosols, which contain abundant dissolvable trace metals. The metal quotas of the zooplankton assemblages have a fairly consistent value as compared to observations from other regions, but algae larger than 10 mm carry overwhelming amounts of extracellular metals even in offshore areas. The stoichiometry concept for trace‐metal composition in marine plankton assemblages is unrealistic in the field.
Biogeochemical composition of natural sea ice brines from the Weddell Sea during early austral summer
Authors: Papadimitriou S. , Thomas D. N. , Kennedy H. , Haas C. , Kuosa H. , Krell A. , Dieckmann G. S.
Published: November 2010

Sea ice brines were collected from a single floe composed of different ice types in the western Weddell Sea in December 2004. The chemical composition of the brines (temperature: 23.4°C to 22.1°C; salinity: 40–63) was examined on seven occasions over 25 days with measurements of dissolved oxygen, dissolved inorganic macronutrients (nitrate plus nitrite, ammonium, phosphorus [DIP], and silicic acid), pH, total alkalinity (AT), dissolved organic carbon (DOC) and nitrogen (DON), total dissolved inorganic carbon (CT), and the stable isotopic composition of CT (δ13CT). The in situ pH ranged from 8.41‐8.82 on the seawater scale, dissolved oxygen from 212‐604 µmol kg−1, nitrate from 0.1‐3.1 µmol kg−1, ammonium 0.1‐2.4 µmol kg−1, DIP 0.4‐ 2.0 µmol kg−1, silicic acid 4‐80 µmol kg−1, AT 2,690‐4,620 µeq kg−1, DOC 115‐359 µmol kg−1, DON 8‐26 µmol kg−1, CT 2,090‐3,550 µmol kg−1, and δ13CT +2.9‰ ‐ +6.4‰. Compared with the chemical composition of surface oceanic water (salinity of 34), the brines had elevated pH, reduced concentrations of dissolved inorganic macronutrients (including carbon), especially dissolved inorganic nitrogen, and were mostly supersaturated with dissolved oxygen with respect to equilibrium with air, whereas the CT was considerably enriched in 13C. The chemical composition of the brines was consistent with internal biological productivity, but there was a lack of a distinctive and uniform relationship among the major dissolved inorganic nutrients typically used for describing biological activity. This was interpreted as the result of varying stoichiometry of biological activity within a very small spatial scale. Modification by abiotic processes was a potential contributing factor, such as degassing acting on the dissolved oxygen concentration. Carbonate mineral formation, acting on AT and CT, was not evident in brines from first‐year ice but was apparent in brine from second‐year ice.
Bed roughness effects on boundary‐layer turbulence and consequences for odor‐tracking behavior of blue crabs (Callinectes sapidus)
Authors: Jackson J. L. , Webster D. R. , Rahman S. , Weissburg M. J.
Published: November 2010

We employed laser‐induced fluorescence (LIF) measurements of odorant plume structure and behavioral observations to examine how turbulence affects the three‐dimensional structure of odorant plumes and subsequently mediates olfactory search efficiency and success in our model organism, the blue crab (Callinectes sapidus). The turbulent characteristics of two laboratory flumes (one for behavioral quantification, one for signal‐structure quantification) were systematically varied by changing the bed substrate roughness to create smooth, transitional, and fully rough flow conditions. Generally, increasing bed roughness caused greater mixing, decreased the time‐averaged odorant concentration and concentration variance, and increased the plume width and homogeneity. Foraging success and speed of blue crabs attempting to locate the odorant source both declined consistently with increasing bed roughness. The variation in signal structure at the height of the antennules among bed‐roughness treatments explains the observed behavior differences in crab foraging speed. In contrast, steering (path linearity) appeared to be unaffected by bed‐roughness‐induced turbulence. The transverse correlation function for odorant concentration at sensors separated across the width of the plume was examined among bed‐roughness treatments, and, ultimately, the correlation function was found to be related to the spatial position of tracking blue crabs. The spatial arrangement of blue crab chemosensors combined with the three‐dimensional structure of odor plumes account for the differential effects of turbulence on the speed and success of crab‐tracking behavior.
The influence of the balance of inorganic and organic nitrogen on the trophic dynamics of microbial food webs
Authors: Davidson Keith , Gilpin Linda C. , Hart Mark C. , Fouilland Eric , Mitchell Elaine , Á lvarez Calleja Ignacio , Laurent CÉline , Miller Axel E. J. , Leakey Raymond J. G.
Published: November 2010

A nutrient‐manipulation mesocosm study was conducted in Norwegian coastal waters to determine the effect on a nitrogen‐limited microbial food web of changes in the relative concentrations of dissolved organic and inorganic nitrogen (N). Four replicated treatments were studied: no N addition, inorganic N, organic N, or a 50 : 50 mix of inorganic and organic N. Comprehensive abundance, biomass, and rate measurements were made over the 20‐d experiment. The form of N available influenced species composition, succession, and the efficiency of carbon (C) incorporation. Inorganic N generated a bloom of the diatom Leptocylindrus danicus, even though silicon concentrations were below 1 µmol L−1. The c‐proteobacteria initially competed effectively with diatoms for inorganic N, exhibiting high productivity and escaping grazing control. Organic N, when available alone, was utilized more slowly by the microbial community, with diatom growth, fueled by regenerated N, achieving a lower peak abundance. A more diverse diatom species assemblage was also evident. The γ‐proteobacteria were less prevalent and net bacterial productivity was initially lower when the N source was organic and, in contrast to the response following inorganic N addition, the bacterial community was initially grazer controlled. A rapid succession of heterotrophic grazers occurred but with differences in species and their contribution to biomass between treatments. The efficiency of C‐biomass production was lower when the N source was purely organic. However, when both inorganic and organic N were available, biomass yield was greater than the mean of the two single N source treatments.
Effects of impoundment on nutrient availability and productivity in lakes
Authors: Matzinger Andreas , Pieters Roger , Ashley Ken I. , Lawrence Gregory A. , WÜest Alfred
Published: November 2010

We investigate the hydraulic alteration and the effect on primary productivity of the Hugh Keenleyside Dam built at the outlet of the Arrow Lakes (British Columbia, Canada) in 1967. Three dam‐induced hydraulic changes have been identified as relevant: (1) water level increase, (2) leveling of the seasonal outflow, and (3) subsurface release of water from the dam. The potential effect of these alterations on primary productivity were tested with a numerical model supported by field observations. Hydraulic modifications can reduce lake productivity by up to 40%, primarily as a result of altered flow path and allowing nutrients to pass through the reservoir without entering the productive zone near the surface. This productivity loss is comparable to the reduction caused by nutrient retention behind dams constructed upstream of the Arrow Lakes Reservoir. The combined productivity loss from both of these two mechanisms is significant and may well be responsible for the dramatic decline of kokanee (Oncorhynchus nerka) observed in the Arrow Lakes Reservoir in the 1990s.
Foraging behavior can influence dispersal of marine organisms
Authors: Woodson C. B. , McManus M. A.
Published: November 2010

It has become increasingly apparent that widely varying behaviors of organisms (e.g., ontogenetic depth preference, selective tidal stream transport, position maintenance) can significantly influence dispersal and connectivity between nearby populations. However, more common day‐to‐day behaviors, such as foraging, are often assumed to have little effect on dispersal at larger scales (tens to thousands of kilometers). In this review, we (1) place foraging within the context of current knowledge on behaviors that influence dispersal and transport, (2) provide evidence for foraging behavior as a driving mechanism of distributions, and (3) present a meta‐analysis of dispersal distances estimated for three dispersal hypotheses (passive, swimming directly against currents, and foraging behavior) from 59 studies that document oceanographic conditions and in situ organism distributions. Results of the analyses reveal that when foraging and aggregative behaviors are considered, dispersal distances for larvae and zooplankton could be hundreds of kilometers less than many current dispersal estimates. Reduced transport because of foraging implies that individual populations might be more isolated than currently accepted. These findings suggest that fine‐scale organism behaviors should be considered in models aimed to improve conservation efforts.
Dissolved organic matter and bacterial production and respiration in the sea‐surface microlayer of the open Atlantic and the western Mediterranean Sea
Authors: Reinthaler Thomas , Sintes Eva , Herndl Gerhard J.
Published: November 2010

The sea‐surface microlayer (SML) is the boundary layer between the ocean and the atmosphere. We measured bacterial production and respiration along with dissolved organic carbon (DOC), nitrogen (DON), and phosphorus, inorganic nutrients, and dissolved amino acids in the SML and the underlying water (ULW) of the subtropical Atlantic gyre (SATL) and the western Mediterranean Sea (WMED). Dissolved amino acid concentrations in the SML were one order of magnitude higher than in the ULW. DON, ammonium, and nitrate were also significantly enriched in the SML as compared with the ULW. Bacterial leucine incorporation ranged between 3 and 50 pmol L‐1 h‐1 in the SATL and 5 and 488 pmol L‐1 h‐1 in the WMED and was generally not significantly different between the SML and the ULW. In contrast, bacterial respiration was significantly higher in the SML than in the ULW, varying between 3.6 and 9.5 µmol L‐1 d‐1 O2 at both sites. The resulting bacterial growth efficiencies ranged between 0.1% and 14% using different leucine incorporation to carbon conversion factors. Given the high dissolved free amino acid (DFAA) yield of DOC (~12%) and of DON (~30%) in the SML, bacterial growth efficiencies in the SML were low. This indicates that the DFAA in the SML are not readily available for bacteria. The underlying mechanisms of this immobilization of DFAA in the SML and their production remain enigmatic.
The influence of dissolved organic carbon on bacterial phosphorus uptake and bacteria‐phytoplankton dynamics in two Minnesota lakes
Authors: Stets Edward G. , Cotner James B.
Published: November 2010

The balance of production in any ecosystem is dependent on the flow of limiting nutrients into either the autotrophic or heterotrophic components of the food web. To understand one of the important controls on the flow of inorganic nutrients between phytoplankton and bacterioplankton in lakes, we manipulated dissolved organic carbon (DOC) in two lakes of different trophic status. We hypothesized that labile DOC additions would increase bacterial phosphorus (P) uptake and decrease the response of phytoplankton to nutrient additions. Supplemental nutrients and carbon (C), nitrogen (N, 1.6 µmol NH4Cl L−1 d−1), P (0.1 µmol KH2PO4 L−1 d−1), and DOC (glucose, 15 µmol C L−1 d−1) were added twice daily to 8‐liter experimental units. We tested the effect of added DOC on chlorophyll concentration, bacterial production, biomass, and P uptake using size‐fractionated 33P‐PO4 uptake. In the oligotrophic lake, DOC additions stimulated bacterial production and increased bacterial biomass‐specific P uptake. Bacteria consumed added DOC, and chlorophyll concentrations were significantly lower in carboys receiving DOC additions. In the eutrophic lake, DOC additions had less of a stimulatory effect on bacterial production and biomass‐specific P uptake. DOC accumulated over the time period, and there was little evidence for a DOC‐induced decrease in phytoplankton biomass. Bacterial growth approached the calculated µmax and yet did not accumulate biomass, indicating significant biomass losses, which may have constrained bacterial DOC consumption. Excess bacterial DOC consumption in oligotrophic lakes may result in greater bacterial P affinity and enhanced nutrient uptake by the heterotrophic compartment of the food web. On the other hand, constraints on bacterial biomass accumulation in eutrophic lakes, from either viral lysis or bacterial grazing, can allow labile DOC to accumulate, thereby negating the effect of excess DOC on the planktonic food web.
Tidal marshes as a source of optically and chemically distinctive colored dissolved organic matter in the Chesapeake Bay
Authors: Tzortziou Maria , Neale Patrick J. , Osburn Christopher L. , Megonigal J. Patrick , Maie Nagamitsu , JaffÉ Rudolf
Published: November 2010

The role of tidal marshes as a source of dissolved organic carbon (DOC) and colored dissolved organic matter (CDOM) for adjacent estuarine waters was studied in the Rhode River subestuary of the Chesapeake Bay. Water in a tidal creek draining brackish, high‐elevation marshes was sampled every hour during several semidiurnal tidal cycles in order to examine the tidal exchange of dissolved organic matter (DOM). Water leaving the marsh during ebbing tide was consistently enriched in DOC compared to water entering the marsh during flooding tide. There was a net DOC export from the marsh to the estuary during seasons of both low and high marsh plant biomass. Optical analysis demonstrated that, in addition to contributing to the carbon budgets, the marsh had a strong influence on the estuary’s CDOM dynamics. Marsh‐exported CDOM had optical properties that were consistently and markedly different from those of CDOM in the adjacent estuary. Specifically, marsh CDOM had: (1) considerably stronger absorption, (2) larger DOC‐specific absorption, (3) lower exponential spectral slope, (4) larger fluorescence signal, (5) lower fluorescence per unit absorbance, and (6) higher fluorescence at wavelengths >400 nm. These optical characteristics are indicative of relatively complex, high‐molecular‐weight, aromatic‐rich DOM, and this was confirmed by results of molecular‐weight‐distribution analysis. Our findings illustrate the importance of tidal marshes as sources of optically and chemically distinctive dissolved organic compounds, and their influence on CDOM dynamics, DOC budgets, and, thus, photochemical and biogeochemical processes, in adjacent estuarine ecosystems.
The role of unchelated Fe in the iron nutrition of phytoplankton
Authors: Morel F. M. M. , Kustka A. B. , Shaked Y.
Published: November 2010

The important question of iron bioavailability in the sea has become complicated by the discovery that marine phytoplankton can take up Fe bound in very stable chelates via reductive processes, and some particular Fe species through specialized transport mechanisms. As a result there is some question of whether the small fraction of Fe that is "free" or unchelated in seawater is important in the nutrition of natural phytoplankton assemblages. A careful examination of published laboratory studies on Fe uptake by model organisms all support the idea that unchelated Fe(III) is highly available for uptake and that it is an important source of the Fe taken up by phytoplankton under a variety of experimental conditions. Comparing these results with field data on Fe speciation shows that unchelated Fe can be an important source of Fe to the phytoplankton in the sea: it is likely sufficient to contribute the bulk of the Fe supporting primary production in regions that are not limited by Fe and a significant fraction everywhere, including high‐nutrient low‐chlorophyll areas.
Explaining metal concentrations in sympatric Chironomus species
Authors: Martin Sylvain , Proulx Isabelle , Hare Landis
Published: November 2010

We compared metal concentrations in larvae of two Chironomus species (Chironomus staegeri and Chironomustigris) living in the same lake and at the same depth and time. Concentrations of the nonessential metal cadmium (Cd) differed greatly (>8x) between the two species, whereas those of two essential metals differed either much less (zinc [Zn], 2x) or not at all (copper [Cu]). These trends were constant in all seasons. On the one hand, differences in Cd and Zn concentrations between the species were not explained by differences in either their size or their life cycle. Likewise, differential exposure to dissolved metals did not explain larval Cd and Zn concentrations because vertical gradients in dissolved metals did not correlate with depths of larval feeding. On the other hand, the species differed in the type of sediment that they consumed, and measurements of sulfur stable isotopes in larvae confirmed that whereas C. staegeri consumes mostly surface oxic sediment, C. tigris eats mainly deeper anoxic sediment. Because total metal concentrations in gut contents were not correlated with those in larvae, it is likely that metal bioavailability differs between the two sediment types. Overall, our results show that because metal concentrations can differ widely between sympatric congeners, extrapolation from one Chironomus species to another may not be justifiable. Furthermore, because larvae exposed to Zn in the laboratory did not accumulate this metal as they would in the field, we suggest that care is warranted when extrapolating from results obtained in laboratory tests to animals living in the field.