Preliminary Data on Eutrophication of Carstic Lakes

OpenAIRE

, B. Hoxha; , F. Cane; , M. Avdolli; , A. Dauti

2016-01-01

Nutrients play an important role in the health and functioning of aquatic ecosystems. However, an excess of nutrients, particularly phosphorous and nitrogen compounds, can lead to adverse effects on both ecology and uses of receiving waters. This process accelerated by human activities is termed cultural eutrophication, and is recognized as a significant environmental problem. The purpose of this paper is to represent some preliminary data on eutrophication of water bodies from a chemical poi...

Exploitation of linkage learning in evolutionary algorithms

CERN Document Server

Chen, Ying-ping

2010-01-01

The exploitation of linkage learning is enhancing the performance of evolutionary algorithms. This monograph examines recent progress in linkage learning, with a series of focused technical chapters that cover developments and trends in the field.

Linkage Behavior and Practices of Agencies in the Agricultural ...

African Journals Online (AJOL)

The study examined the linkage behaviour and practices of agencies in the ... institutes; while (61.5%,65.5%and 50.0%) indicated that linkages with universities of ... Existing institutional framework for linkages between research and extension ...

Improving the accuracy of estimation of eutrophication state index ...

African Journals Online (AJOL)

Trophic Level Index (TLI) is oen used to assess the general eutrophication state of inland lakes in water science, technology, and engineering. In this paper, a data-driven inland-lake eutrophication assessment method was proposed by using an articial neural network (ANN) to build relationships from remote sensing data ...

Saltmarsh plant responses to eutrophication.

Science.gov (United States)

Johnson, David Samuel; Warren, R Scott; Deegan, Linda A; Mozdzer, Thomas J

2016-12-01

In saltmarsh plant communities, bottom-up pressure from nutrient enrichment is predicted to increase productivity, alter community structure, decrease biodiversity, and alter ecosystem functioning. Previous work supporting these predictions has been based largely on short-term, plot-level (e.g., 1-300 m 2 ) studies, which may miss landscape-level phenomena that drive ecosystem-level responses. We implemented an ecosystem-scale, nine-year nutrient experiment to examine how saltmarsh plants respond to simulated conditions of coastal eutrophication. Our study differed from previous saltmarsh enrichment studies in that we applied realistic concentrations of nitrate (70-100 μM NO 3 - ), the most common form of coastal nutrient enrichment, via tidal water at the ecosystem scale (~60,000 m 2 creeksheds). Our enrichments added a total of 1,700 kg N·creek -1 ·yr -1 , which increased N loading 10-fold vs. reference creeks (low-marsh, 171 g N·m -2 ·yr -1 ; high-marsh, 19 g N·m -2 ·yr -1 ). Nutrients increased the shoot mass and height of low marsh, tall Spartina alterniflora; however, declines in stem density resulted in no consistent increase in aboveground biomass. High-marsh plants S. patens and stunted S. alterniflora did not respond consistently to enrichment. Nutrient enrichment did not shift community structure, contrary to the prediction of nutrient-driven dominance of S. alterniflora and Distichlis spicata over S. patens. Our mild responses may differ from the results of previous studies for a number of reasons. First, the limited response of the high marsh may be explained by loading rates orders of magnitude lower than previous work. Low loading rates in the high marsh reflect infrequent inundation, arguing that inundation patterns must be considered when predicting responses to estuarine eutrophication. Additionally, we applied nitrate instead of the typically used ammonium, which is energetically favored over nitrate for plant uptake. Thus, the

Geo-engineering experiments in two urban ponds to control eutrophication

NARCIS (Netherlands)

Waaijen, G.; Oosterhout, J.F.X.; Douglas, G.C.; Lurling, M.F.L.L.W.

2016-01-01

Many urban ponds experience detrimental algal blooms as the result of eutrophication. During a two year field experiment, the efficacy of five in situ treatments to mitigate eutrophication effects in urban ponds was studied. The treatments targeted the sediment phosphorus release and were intended

[Lake eutrophication modeling in considering climatic factors change: a review].

Science.gov (United States)

Su, Jie-Qiong; Wang, Xuan; Yang, Zhi-Feng

2012-11-01

Climatic factors are considered as the key factors affecting the trophic status and its process in most lakes. Under the background of global climate change, to incorporate the variations of climatic factors into lake eutrophication models could provide solid technical support for the analysis of the trophic evolution trend of lake and the decision-making of lake environment management. This paper analyzed the effects of climatic factors such as air temperature, precipitation, sunlight, and atmosphere on lake eutrophication, and summarized the research results about the lake eutrophication modeling in considering in considering climatic factors change, including the modeling based on statistical analysis, ecological dynamic analysis, system analysis, and intelligent algorithm. The prospective approaches to improve the accuracy of lake eutrophication modeling with the consideration of climatic factors change were put forward, including 1) to strengthen the analysis of the mechanisms related to the effects of climatic factors change on lake trophic status, 2) to identify the appropriate simulation models to generate several scenarios under proper temporal and spatial scales and resolutions, and 3) to integrate the climatic factors change simulation, hydrodynamic model, ecological simulation, and intelligent algorithm into a general modeling system to achieve an accurate prediction of lake eutrophication under climatic change.

Sewage-effluent phosphorus: A greater risk to river eutrophication than agricultural phosphorus?

International Nuclear Information System (INIS)

Jarvie, Helen P.; Neal, Colin; Withers, Paul J.A.

2006-01-01

Phosphorus (P) concentrations from water quality monitoring at 54 UK river sites across seven major lowland catchment systems are examined in relation to eutrophication risk and to the relative importance of point and diffuse sources. The over-riding evidence indicates that point (effluent) rather than diffuse (agricultural) sources of phosphorus provide the most significant risk for river eutrophication, even in rural areas with high agricultural phosphorus losses. Traditionally, the relative importance of point and diffuse sources has been assessed from annual P flux budgets, which are often dominated by diffuse inputs in storm runoff from intensively managed agricultural land. However, the ecological risk associated with nuisance algal growth in rivers is largely linked to soluble reactive phosphorus (SRP) concentrations during times of ecological sensitivity (spring/summer low-flow periods), when biological activity is at its highest. The relationships between SRP and total phosphorus (TP; total dissolved P + suspended particulate P) concentrations within UK rivers are evaluated in relation to flow and boron (B; a tracer of sewage effluent). SRP is the dominant P fraction (average 67% of TP) in all of the rivers monitored, with higher percentages at low flows. In most of the rivers the highest SRP concentrations occur under low-flow conditions and SRP concentrations are diluted as flows increase, which is indicative of point, rather than diffuse, sources. Strong positive correlations between SRP and B (also TP and B) across all the 54 river monitoring sites also confirm the primary importance of point source controls of phosphorus concentrations in these rivers, particularly during spring and summer low flows, which are times of greatest eutrophication risk. Particulate phosphorus (PP) may form a significant proportion of the phosphorus load to rivers, particularly during winter storm events, but this is of questionable relevance for river eutrophication

EUTROPHICATION OF WATER RESERVOIRS AND ROLE OF MACROPHYTES IN THIS PROCESS

Directory of Open Access Journals (Sweden)

Joanna Jadwiga Sender

2017-06-01

Full Text Available The paper presents the problem related with the process of eutrophication, with special emphasis on dam reservoirs. Eutrophication is a global process, threatening the water ecosystem on every continent. It often leads to their degradation. Particularly vulnerable to eutrophication are artificial reservoirs which are dam reservoirs. This paper describes the mechanisms of eutrophication. We also pointed to the importance of aquatic plants in the process of water purification, as well as the possibility of multilateral use. Recently, in the world and in Poland there is a tendency to pay attention to the natural or semi-natural method of water purification (including constructed wetland. On the one hand, the presence of macrophytes in water bodies is a guarantor of good ecological status, on the other hand, the undeniable aesthetic value.

When to conduct probabilistic linkage vs. deterministic linkage? A simulation study.

Science.gov (United States)

Zhu, Ying; Matsuyama, Yutaka; Ohashi, Yasuo; Setoguchi, Soko

2015-08-01

When unique identifiers are unavailable, successful record linkage depends greatly on data quality and types of variables available. While probabilistic linkage theoretically captures more true matches than deterministic linkage by allowing imperfection in identifiers, studies have shown inconclusive results likely due to variations in data quality, implementation of linkage methodology and validation method. The simulation study aimed to understand data characteristics that affect the performance of probabilistic vs. deterministic linkage. We created ninety-six scenarios that represent real-life situations using non-unique identifiers. We systematically introduced a range of discriminative power, rate of missing and error, and file size to increase linkage patterns and difficulties. We assessed the performance difference of linkage methods using standard validity measures and computation time. Across scenarios, deterministic linkage showed advantage in PPV while probabilistic linkage showed advantage in sensitivity. Probabilistic linkage uniformly outperformed deterministic linkage as the former generated linkages with better trade-off between sensitivity and PPV regardless of data quality. However, with low rate of missing and error in data, deterministic linkage performed not significantly worse. The implementation of deterministic linkage in SAS took less than 1min, and probabilistic linkage took 2min to 2h depending on file size. Our simulation study demonstrated that the intrinsic rate of missing and error of linkage variables was key to choosing between linkage methods. In general, probabilistic linkage was a better choice, but for exceptionally good quality data (<5% error), deterministic linkage was a more resource efficient choice. Copyright © 2015 Elsevier Inc. All rights reserved.

Analysis of Mathematics and Sustainability in an Impulsive Eutrophication Controlling System

Directory of Open Access Journals (Sweden)

Hengguo Yu

2013-01-01

quite accurate to describe the interaction effect of some critical factors (fishermen catch and releasing small fry, etc., which enables a systematic and logical procedure for fitting eutrophication mathematical system to real monitoring data and experiment data. Mathematical theoretical works have been pursuing the investigation of two threshold functions of some critical parameters under the condition of all species persistence, which can in turn provide a theoretical basis for the numerical simulation. Using numerical simulation works, we mainly focus on how to choose the best value of some critical parameters to ensure the sustainability of the eutrophication system so that the eutrophication removal process can be well developed with maximizing economic benefit. These results may be further extended to provide a basis for simulating the algal bloom in the laboratory and understanding the application of some impulsive controlling models about eutrophication removal problems.

Agriculture–Tourism Linkages in Botswana: Evidence from the ...

African Journals Online (AJOL)

Tourism researchers are increasingly recognising that strengthened linkages between the sectors of tourism and agriculture are significant for maximising local multipliers and especially for pro-poor impacts. This article examines the linkages between the tourism and agriculture sectors in Botswana using evidence ...

Eutrophication: present reality and future challenges for South Africa

OpenAIRE

van Ginkel, CE

2011-01-01

During the past 40 years, eutrophication has become an increasing threat to the usability of South African freshwater resources. Despite legislation moderating the discharge of phosphorus from some wastewater treatment works since the 1980s, eutrophication of freshwater resources is now widespread. Two important consequences are blooms of cyanobacteria, carrying the threat of cyanotoxin contamination, and excessive growth of macrophytes, which clog water-supply structures and reduce the recre...

The score statistic of the LD-lod analysis: detecting linkage adaptive to linkage disequilibrium.

Science.gov (United States)

Huang, J; Jiang, Y

2001-01-01

We study the properties of a modified lod score method for testing linkage that incorporates linkage disequilibrium (LD-lod). By examination of its score statistic, we show that the LD-lod score method adaptively combines two sources of information: (a) the IBD sharing score which is informative for linkage regardless of the existence of LD and (b) the contrast between allele-specific IBD sharing scores which is informative for linkage only in the presence of LD. We also consider the connection between the LD-lod score method and the transmission-disequilibrium test (TDT) for triad data and the mean test for affected sib pair (ASP) data. We show that, for triad data, the recessive LD-lod test is asymptotically equivalent to the TDT; and for ASP data, it is an adaptive combination of the TDT and the ASP mean test. We demonstrate that the LD-lod score method has relatively good statistical efficiency in comparison with the ASP mean test and the TDT for a broad range of LD and the genetic models considered in this report. Therefore, the LD-lod score method is an interesting approach for detecting linkage when the extent of LD is unknown, such as in a genome-wide screen with a dense set of genetic markers. Copyright 2001 S. Karger AG, Basel

Comprehensive assessment of coastal eutrophication in Taiwan and its implications for management strategy.

Science.gov (United States)

Liu, Ta-Kang; Chen, Ping; Chen, Hou-Yu

2015-08-15

Due to the rapid population growth, anthropogenic activities result in agricultural, industrial, and urban diffuse runoffs that elevate the level of nutrients such as nitrogen and phosphorus in coastal waters. Currently there is no integrated analysis for coastal eutrophication in Taiwan. A comprehensive analysis of the coastal eutrophic status was performed in this study based on decade-long coastal water quality monitoring data from Taiwan's Environmental Protection Administration. A 3-tiered monitoring strategy is recommended based on the severity of the current eutrophication state. Results indicate that the most problematic area of coastal eutrophication is located in the estuary of the Donggang River (DGR) and its adjacent coastal waters, i.e., the Kao-Ping mouth (KPM) and Dapeng Bay (DPB) in south-western Taiwan. With a worsening eutrophic status, these areas demand intensive monitoring and research with higher spatial and temporal resolutions to evaluate the stresses of nutrient forcing and predict possible future responses. Copyright © 2015 Elsevier Ltd. All rights reserved.

Phosphorus and nitrogen in the eutrophication of waters

International Nuclear Information System (INIS)

Salonen, S.; Frisk, T.; Kaermeniemi, T.; Niemi, J.; Pitkaenen, H.; Silvo, K.; Vuoristo, H.

1992-01-01

This report is a summary of the contribution of nitrogen and phosphorus in the eutrophication process of inland and coastal waters. Special attention was paid to the mechanisms of these nutrients in regulating biological processes and to the methods available in estimating their effects in the eutrophication of water bodies. The report includes five chapters which are entitled: Introduction, which is a general background to the subject with special attention to the requirements of the Finnish Water Act. Phosphorus and nitrogen as factors regulating biological processes. The topics included are: definition of eutrophication, forms of phosphorus and nitrogen and their sources to inland and coastal waters, effects of these nutrients as growth factors of phytoplankton and macrophytes and consequences of eutrophication. Estimation of the effects of phosphorus and nitrogen. The topics discussed from the point of view of the tasks of the National Board of Waters and the Environment are: estimation of the effects of phosphorus and nitrogen in the planning and supervision of industry, fish farming, peat production, municipalities, agriculture and forestry. A brief state-of-the art of the research carried out in the National Board of Waters and the Environment is given. Methods of estimating the effects of phosphorus and nitrogen loading in waters. The topics are: relationships between phosphorus and nitrogen concentrations in waters, material balances, water quality models, classification of waters and different groups of organisms as indicators of water quality. Conclusions for the estimation of the effects of phosphorus and nitrogen in receiving waters

Effects of aquaculture researchers' job characteristics on linkage ...

African Journals Online (AJOL)

The study examined the effects of researchers' job characteristics on linkage activities in Nigeria due to the fact that many fish farmers have not been properly reached with technologies and the problem of poor fish production has been attributed to the weak linkages existing between research, extension and fish farmers.

Review on methodology for LCIA of marine eutrophication

DEFF Research Database (Denmark)

Larsen, Henrik Fred

As part of the ongoing EU FP7 project LC-Impact (www.lc-impact.eu) new life cycle impact assessment (LCIA) methods are going to be developed and tested on industry cases. Among the life cycle assessment (LCA) impact categories in focus are aquatic eutrophication. As related to especially the marine...... concentration and the potentially affected fraction of species in the marine ecosystem. This poster will present a review of the very limited existing attempts on how to include marine eutrophication in LCA and discuss alternative methodologies on how to model the environmental mechanism of this impact category....

Probabilistic record linkage.

Science.gov (United States)

Sayers, Adrian; Ben-Shlomo, Yoav; Blom, Ashley W; Steele, Fiona

2016-06-01

Studies involving the use of probabilistic record linkage are becoming increasingly common. However, the methods underpinning probabilistic record linkage are not widely taught or understood, and therefore these studies can appear to be a 'black box' research tool. In this article, we aim to describe the process of probabilistic record linkage through a simple exemplar. We first introduce the concept of deterministic linkage and contrast this with probabilistic linkage. We illustrate each step of the process using a simple exemplar and describe the data structure required to perform a probabilistic linkage. We describe the process of calculating and interpreting matched weights and how to convert matched weights into posterior probabilities of a match using Bayes theorem. We conclude this article with a brief discussion of some of the computational demands of record linkage, how you might assess the quality of your linkage algorithm, and how epidemiologists can maximize the value of their record-linked research using robust record linkage methods. © The Author 2015; Published by Oxford University Press on behalf of the International Epidemiological Association.

Ocean acidification with (de)eutrophication will alter future phytoplankton growth and succession

DEFF Research Database (Denmark)

Flynn, Kevin J.; Darren, Clark R.; Mitra, Aditee

2015-01-01

Human activity causes ocean acidification (OA) though the dissolution of anthropogenically generated CO2 into seawater, and eutrophication through the addition of inorganic nutrients. Eutrophication increases the phytoplankton biomass that can be supported during a bloom, and the resultant uptake...

Eutrophication, Nile perch and food-web interactions in south-east Lake Victoria

NARCIS (Netherlands)

Cornelissen, I.J.M.

2015-01-01

The increasing eutrophication, the introduction of Nile perch (Lates niloticus) and the increasing fishing pressure has changed Lake Victoria tremendously the last century. Since the 1960s, eutrophication increased primary production, enabling an increase in fish production. However,

Editorial - A critical perspective on geo-engineering for eutrophication management in lakes

NARCIS (Netherlands)

Lurling, Miguel; Mackay, Eleanor; Reitzel, Kasper; Spears, Bryan M.

2016-01-01

Eutrophication is the primary worldwide water quality issue. Reducing excessive external nutrient loading is the most straightforward action in mitigating eutrophication, but lakes, ponds and reservoirs often show little, if any, signs of recovery in the years following external load reduction.

Responses of primary production, leaf litter decomposition and associated communities to stream eutrophication

International Nuclear Information System (INIS)

Dunck, Bárbara; Lima-Fernandes, Eva; Cássio, Fernanda; Cunha, Ana; Rodrigues, Liliana; Pascoal, Cláudia

2015-01-01

We assessed the eutrophication effects on leaf litter decomposition and primary production, and on periphytic algae, fungi and invertebrates. According to the subsidy-stress model, we expected that when algae and decomposers were nutrient limited, their activity and diversity would increase at moderate levels of nutrient enrichment, but decrease at high levels of nutrients, because eutrophication would lead to the presence of other stressors and overwhelm the subsidy effect. Chestnut leaves (Castanea sativa Mill) were enclosed in mesh bags and immersed in five streams of the Ave River basin (northwest Portugal) to assess leaf decomposition and colonization by invertebrates and fungi. In parallel, polyethylene slides were attached to the mesh bags to allow colonization by algae and to assess primary production. Communities of periphytic algae and decomposers discriminated the streams according to the trophic state. Primary production decomposition and biodiversity were lower in streams at both ends of the trophic gradient. - Highlights: • Algae and decomposers discriminated the streams according to the eutrophication level. • Primary production and litter decomposition are stimulated by moderate eutrophication. • Biodiversity and process rates were reduced in highly eutrophic streams. • Subsidy-stress model explained biodiversity and process rates under eutrophication. - Rates of leaf litter decomposition, primary production and richness of periphytic algae, fungi and invertebrates were lower in streams at both ends of the trophic gradient

The Geochemical Record of Cultural Eutrophication and Remediation Efforts in Three Connecticut Lakes

Science.gov (United States)

Ku, T.; Bourne, H. L.; Tirtajana, S.; Nahar, M.; Kading, T.

2009-12-01

Cultural eutrophication is the process whereby human activity increases the amount of nutrients, primarily nitrogen and phosphorous, entering an aquatic ecosystem causing excessive biological growth. To reverse or decelerate cultural eutrophication, many regulatory agencies have implemented stringent laws intended to lower the flux of nutrients into impacted water bodies or have emplaced internal remediation systems designed to decrease primary productivity. To quantify the effects of cultural eutrophication and remediation efforts, we examined sedimentary histories of three eutrophic Connecticut lakes that record the transition from pre-anthropogenic conditions into eutrophication and through recent remediation. The three Connecticut lakes (Lake Waramaug, Beseck Lake, and Amos Lake) represent a range of remediation activities. Since 1983, Lake Waramaug has been the focus of significant remediation efforts including the installation of three hypolimnetic withdrawal / layer aeration systems, zoning regulations to limit runoff, and the stocking and seeding of fish and zooplankton. Beseck Lake has experienced episodic eutrophic conditions, in part due to failing septic systems, and in 2001, 433 residences were converted from septic systems to a city sewer system. Amos Lake serves as a cultural eutrophication end member as it has not has received any major remediation. Multiple freeze and gravity cores were collected from 2005-2008. Radiocarbon, Pb-210, Cs-137, Hg, and Pb measurements determined sediment ages. Organic C accumulation rates, C/N ratios, organic matter delta-15N, bulk sediment Fe and Al concentrations, and P speciation (labile, iron-bound, aluminum-bound, organic, and total) determined sediment and nutrient sources and accumulations. Dithionite-extractable iron, pyrite S, and pyrite delta-34S provided insight into changes in P-Fe-S cycling. The sediment cores represent the last few hundreds of years of lake history and, importantly, some Lake Waramaug

[Eutrophication control in local area by physic-ecological engineering].

Science.gov (United States)

Li, Qiu-Hua; Xia, Pin-Hua; Wu, Hong; Lin, Tao; Zhang, You-Chun; Li, Cun-Xiong; Chen, Li-Li; Yang, Fan

2012-07-01

An integrated physical and ecological engineering experiment for ecological remediation was performed at the Maixi River bay in Baihua Reservoir Guizhou Province, China. The results show that eutrophic parameters, such as total nitrogen, total phosphorus, chlorophyll a and chemical oxygen demand from the experimental site (enclosed water) were significantly lower than those of the reference site. The largest differences between the sites were 0.61 mg x L(-1), 0.041 mg x L(-1), 23.06 microg x L(-1), 8.4 mg x L(-1) respectively; experimental site transparency was > 1.50 m which was significantly higher than that of the reference site. The eutrophic index of the experimental site was oligo-trophic and mid-trophic, while the control site was mid-trophic state and eutrophic state. Phytoplankton abundance was 2 125.5 x 10(4) cells x L(-1) in June, 2011 at the control site,but phytoplankton abundance was lower at the experimental site with 33 x 10(4) cells x L(-1). Cyanobacteria dominated phytoplankton biomass at both sites, however the experimental site consisted of a higher proportion of diatoms and dinoflagellates. After more than one year of operation, the ecological engineering technology effectively controlled the occurrence of algae blooms, changed phytoplankton community structure, and controlled the negative impacts of eutrophication. Integrating physical and ecological engineering technology could improve water quality for reservoirs on the Guizhou plateau.

Eutrophication signals in the sedimentary record of dinoflagellate cysts in coastal waters

Science.gov (United States)

Dale, Barrie

2009-01-01

A brief review is presented of the current status of eutrophication signals from the sedimentary records of dinoflagellate cysts in coastal waters, particularly of NW Europe. There is a dearth of the multi-decadal time series data from plankton needed to document eutrophication, and the cysts may provide an alternative source of information. Two different eutrophication signals have been described so far from cyst records: 1) from the Oslofjord, comprising a marked increase in total cyst concentrations (interpreted as probably reflecting increased phytoplankton productivity), with Lingulodinium polyedrum cysts accounting for most of the increase (interpreted as a species particularly benefiting from added nutrients from cultural eutrophication in late summer when nutrients otherwise may be limiting); and 2) the heterotroph signal, from several other Norwegian fjords and Tokyo Bay, Japan, involving both cases of increased cyst concentrations and others with no particular increase, but with a marked proportional increase in cysts of heterotrophic species (interpreted as reflecting increased diatoms and possibly other prey for the heterotrophic dinoflagellates and/or more unfavourable conditions for autotrophs, e.g. from shading). These signals should be used critically, and there is a particular need to distinguish between eutrophication signals and climate signals that may be co-occurring at a given time. Work by various authors has generally supported the concept of these cyst-based signals since they were first published, including both further records from cored sediments from other parts of the world and studies relating cyst distributions in surface sediments to gradients of pollution and nutrients from sewage discharge. Recent, unpublished work by Dale and Sætre, linked cyst signals in cored sediments to the timing of collapse of local fisheries at different times within the past fifty years in four fjord systems along the Norwegian Skagerrak coast

Data Linkage in VET Research: Opportunities, Challenges and Principles. Discussion Paper

Science.gov (United States)

Osborne, Kristen; Fowler, Craig; Circelli, Michelle

2018-01-01

This discussion paper explores the possibilities and risks that data linkage presents for the vocational education and training (VET) sector. Along with a broad overview of the nature of data linkage, it highlights possible applications for data linkage in the VET sector and examines the key challenges associated with its use. A number of case…

Variable selection for modelling effects of eutrophication on stream and river ecosystems

NARCIS (Netherlands)

Nijboer, R.C.; Verdonschot, P.F.M.

2004-01-01

Models are needed for forecasting the effects of eutrophication on stream and river ecosystems. Most of the current models do not include differences in local stream characteristics and effects on the biota. To define the most important variables that should be used in a stream eutrophication model,

Overview of eutrophication indicators to assess environmental status within the European Marine Strategy Framework Directive

Science.gov (United States)

Ferreira, João G.; Andersen, Jesper H.; Borja, Angel; Bricker, Suzanne B.; Camp, Jordi; Cardoso da Silva, Margarida; Garcés, Esther; Heiskanen, Anna-Stiina; Humborg, Christoph; Ignatiades, Lydia; Lancelot, Christiane; Menesguen, Alain; Tett, Paul; Hoepffner, Nicolas; Claussen, Ulrich

2011-06-01

In 2009, following approval of the European Marine Strategy Framework Directive (MSFD, 2008/56/EC), the European Commission (EC) created task groups to develop guidance for eleven quality descriptors that form the basis for evaluating ecosystem function. The objective was to provide European countries with practical guidelines for implementing the MSFD, and to produce a Commission Decision that encapsulated key points of the work in a legal framework. This paper presents a review of work carried out by the eutrophication task group, and reports our main findings to the scientific community. On the basis of an operational, management-oriented definition, we discuss the main methodologies that could be used for coastal and marine eutrophication assessment. Emphasis is placed on integrated approaches that account for physico-chemical and biological components, and combine both pelagic and benthic symptoms of eutrophication, in keeping with the holistic nature of the MSFD. We highlight general features that any marine eutrophication model should possess, rather than making specific recommendations. European seas range from highly eutrophic systems such as the Baltic to nutrient-poor environments such as the Aegean Sea. From a physical perspective, marine waters range from high energy environments of the north east Atlantic to the permanent vertical stratification of the Black Sea. This review aimed to encapsulate that variability, recognizing that meaningful guidance should be flexible enough to accommodate the widely differing characteristics of European seas, and that this information is potentially relevant in marine ecosystems worldwide. Given the spatial extent of the MSFD, innovative approaches are required to allow meaningful monitoring and assessment. Consequently, substantial logistic and financial challenges will drive research in areas such as remote sensing of harmful algal blooms, in situ sensor development, and mathematical models. Our review takes into

Eutrophication assessment of the Baltic Sea Protected Areas by available data and GIS technologies.

Science.gov (United States)

Ranft, Susanne; Pesch, Roland; Schröder, Winfried; Boedeker, Dieter; Paulomäki, Hanna; Fagerli, Hilde

2011-01-01

Concerning increased degradation of marine ecosystems, there is a great political and institutional demand for an array of different tools to restore a good environmental status. Thereby, eutrophication is acknowledged as one of the major human induced stressors which has to be monitored and reduced. The present study concentrates on an assessment of the eutrophication status of the Baltic Sea Protected Areas by use of available data and GIS technologies. Two geodata layers were used for analysis: (1) a map on the eutrophication status of the Baltic Sea generated by the Helsinki Commission applying the HELCOM Eutrophication Assessment Tool (HEAT), and (2) modelled data on atmospheric nitrogen deposition made available by the European Monitoring and Evaluation Programme (EMEP). The results yielded comprehensive and conclusive data indicating that most of the BSPAs may be classified as being 'affected by eutrophication' and underlining the need to decrease the overall emissions of nutrients. Copyright © 2011 Elsevier Ltd. All rights reserved.

Editorial - A critical perspective on geo-engineering for eutrophication management in lakes.

Science.gov (United States)

Lürling, Miquel; Mackay, Eleanor; Reitzel, Kasper; Spears, Bryan M

2016-06-15

Eutrophication is the primary worldwide water quality issue. Reducing excessive external nutrient loading is the most straightforward action in mitigating eutrophication, but lakes, ponds and reservoirs often show little, if any, signs of recovery in the years following external load reduction. This is due to internal cycling of phosphorus (P). Geo-engineering, which we can here define as activities intervening with biogeochemical cycles to control eutrophication in inland waters, represents a promising approach, under appropriate conditions, to reduce P release from bed sediments and cyanobacteria accumulation in surface waters, thereby speeding up recovery. In this overview, we draw on evidence from this special issue Geoengineering in Lakes, and on supporting literature to provide a critical perspective on the approach. We demonstrate that many of the strong P sorbents in the literature will not be applicable in the field because of costs and other constraints. Aluminium and lanthanum modified compounds are among the most effective compounds for targeting P. Flocculants and ballast compounds can be used to sink cyanobacteria, in the short term. We emphasize that the first step in managing eutrophication is a system analysis that will reveal the main water and P flows and the biological structure of the waterbody. These site specific traits can be significant confounding factors dictating successful eutrophication management. Geo-engineering techniques, considered collectively, as part of a tool kit, may ensure successful management of eutrophication through a range of target effects. In addition, novel developments in modified zeolites offer simultaneous P and nitrogen control. To facilitate research and reduce the delay from concept to market a multi-national centre of excellence is required. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of coastal eutrophication on heavy metal bioaccumulation and oral bioavailability in the razor clam, Sinonovacula constricta

Energy Technology Data Exchange (ETDEWEB)

Tu, Tengxiu [College of Chemistry and Environment, Minnan Normal University, Zhangzhou 363000 (China); Li, Shunxing, E-mail: lishunxing@mnnu.edu.cn [College of Chemistry and Environment, Minnan Normal University, Zhangzhou 363000 (China); Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology (China); Chen, Lihui [College of Chemistry and Environment, Minnan Normal University, Zhangzhou 363000 (China); Zheng, Fengying; Huang, Xu-Guang [College of Chemistry and Environment, Minnan Normal University, Zhangzhou 363000 (China); Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology (China)

2014-10-15

Graphical abstract: - Highlights: • Razor clams are often exposed to coastal eutrophication. • The bioaccumulation of Fe, Ni, V, and As was promoted by eutrophication. • Bionic gastrointestinal tract was used for metal oral bioavailability assessment. • Eutrophication decreased oral bioavailability of Fe and Pb but enhanced for V. • The daily maximum allowable intakes are controlled by eutrophication levels. - Abstract: As traditional seafoods, the razor clams are widely distributed from tropical to temperate areas. Coastal razor clams are often exposed to eutrophication. Heavy metal contamination is critical for seafood safety. However, how eutrophication affects bioaccumulation and oral bioavailability of heavy metals in the razor clams is unknown. After a four-month field experimental cultivation, heavy metals (Fe, Cu, Ni, V, As, and Pb) could be bioaccumulated by the razor clams (Sinonovacula constricta) through exposure to metals present in water and sediments or in the food chain, and then transferred to human via consumption of razor clams. Bionic gastrointestinal digestion and monolayer liposome extraction are used for metal oral bioavailability (OBA) assessment. The influence of eutrophication on OBA is decreased for Fe and Pb and increased for V. A significant positive linear correlation was observed between the bioaccumulation factors of Fe, Ni, V, and As in razor clams and the coastal eutrophication. These results may be due to the effect of eutrophication on metal species transformation in coastal seawater and subcellular distribution in razor clams. The maximum allowable daily intakes of razor clams are controlled by eutrophication status and the concentration of affinity-liposome As in razor clams.

Effect of coastal eutrophication on heavy metal bioaccumulation and oral bioavailability in the razor clam, Sinonovacula constricta

International Nuclear Information System (INIS)

Tu, Tengxiu; Li, Shunxing; Chen, Lihui; Zheng, Fengying; Huang, Xu-Guang

2014-01-01

Graphical abstract: - Highlights: • Razor clams are often exposed to coastal eutrophication. • The bioaccumulation of Fe, Ni, V, and As was promoted by eutrophication. • Bionic gastrointestinal tract was used for metal oral bioavailability assessment. • Eutrophication decreased oral bioavailability of Fe and Pb but enhanced for V. • The daily maximum allowable intakes are controlled by eutrophication levels. - Abstract: As traditional seafoods, the razor clams are widely distributed from tropical to temperate areas. Coastal razor clams are often exposed to eutrophication. Heavy metal contamination is critical for seafood safety. However, how eutrophication affects bioaccumulation and oral bioavailability of heavy metals in the razor clams is unknown. After a four-month field experimental cultivation, heavy metals (Fe, Cu, Ni, V, As, and Pb) could be bioaccumulated by the razor clams (Sinonovacula constricta) through exposure to metals present in water and sediments or in the food chain, and then transferred to human via consumption of razor clams. Bionic gastrointestinal digestion and monolayer liposome extraction are used for metal oral bioavailability (OBA) assessment. The influence of eutrophication on OBA is decreased for Fe and Pb and increased for V. A significant positive linear correlation was observed between the bioaccumulation factors of Fe, Ni, V, and As in razor clams and the coastal eutrophication. These results may be due to the effect of eutrophication on metal species transformation in coastal seawater and subcellular distribution in razor clams. The maximum allowable daily intakes of razor clams are controlled by eutrophication status and the concentration of affinity-liposome As in razor clams

Larval growth in the dominant polychaete Polydora ciliata is food-limited in a eutrophic Danish estuary (Isefjord)

DEFF Research Database (Denmark)

Pedersen, Troels Møller; Almeda, Rodrigo; Fotel, Frank Lech

2010-01-01

Food limitation in larval growth of the spionid polychaete Polydora ciliata was examined in a typical eutrophic estuary, Isefjord, in Denmark. In the field, food availability and the energetic requirements of the P. ciliata larval population were measured during 2 different periods in 2004 and 20...

Lake Baikal Ecosystem Faces the Threat of Eutrophication

Directory of Open Access Journals (Sweden)

Galina I. Kobanova

2016-01-01

Full Text Available Recently there have been reports about large accumulations of algae on the beaches of Lake Baikal, the oldest and deepest freshwater body on earth, near major population centers and in areas with large concentrations of tourists and tourism infrastructure. To evaluate the observations indicating the ongoing process of eutrophication of Lake Baikal, a field study in July 2012 in the two largest bays of Lake Baikal, Barguzinsky and Chivyrkuisky, was organized. The study of phytoplankton using the sedimentary method and quantitative records of accumulations of macrophytes in the surf zone was made. In Chivyrkuisky Bay, we found the massive growth of colorless flagellates and cryptomonads as well as the aggregations of Elodea canadensis along the sandy shoreline (up to 26 kg/m2. Barguzinsky Bay registered abundantly cyanobacterial Anabaena species, cryptomonads, and extremely high biomass of Spirogyra species (up to 70 kg/m3. The results show the presence of local but significant eutrophication of investigated bays. To prevent further extensions of this process in unique ecosystem of Lake Baikal, the detailed study and monitoring of the coastal zone, the identification of the sources of eutrophication, and the development of measures to reduce nutrient inputs in the waters are urgently needed.

Subsidiary Linkage Patterns

DEFF Research Database (Denmark)

Andersson, Ulf; Perri, Alessandra; Nell, Phillip C.

2012-01-01

channels for spillovers to competitors. We find a curvilinear relationship between the extent of competitive pressure and the quality of a subsidiary's set of local linkages. Furthermore, the extent to which a subsidiary possesses capabilities moderates this relationship: Very capable subsidiaries...... in strongly competitive environments tend to shy away from high quality linkages. We discuss our findings in light of the literature on spillovers and inter-organizational linkages.......This paper investigates the pattern of subsidiaries' local vertical linkages under varying levels of competition and subsidiary capabilities. Contrary to most previous literature, we explicitly account for the double role of such linkages as conduits of learning prospects as well as potential...

Interactive effects of warming, eutrophication and size structure: impacts on biodiversity and food-web structure.

Science.gov (United States)

Binzer, Amrei; Guill, Christian; Rall, Björn C; Brose, Ulrich

2016-01-01

Warming and eutrophication are two of the most important global change stressors for natural ecosystems, but their interaction is poorly understood. We used a dynamic model of complex, size-structured food webs to assess interactive effects on diversity and network structure. We found antagonistic impacts: Warming increases diversity in eutrophic systems and decreases it in oligotrophic systems. These effects interact with the community size structure: Communities of similarly sized species such as parasitoid-host systems are stabilized by warming and destabilized by eutrophication, whereas the diversity of size-structured predator-prey networks decreases strongly with warming, but decreases only weakly with eutrophication. Nonrandom extinction risks for generalists and specialists lead to higher connectance in networks without size structure and lower connectance in size-structured communities. Overall, our results unravel interactive impacts of warming and eutrophication and suggest that size structure may serve as an important proxy for predicting the community sensitivity to these global change stressors. © 2015 John Wiley & Sons Ltd.

Disentangling the effects of a century of eutrophication and climate warming on freshwater lake fish assemblages.

Directory of Open Access Journals (Sweden)

Peter C Jacobson

Full Text Available Eutrophication and climate warming are profoundly affecting fish in many freshwater lakes. Understanding the specific effects of these stressors is critical for development of effective adaptation and remediation strategies for conserving fish populations in a changing environment. Ecological niche models that incorporated the individual effects of nutrient concentration and climate were developed for 25 species of fish sampled in standard gillnet surveys from 1,577 Minnesota lakes. Lake phosphorus concentrations and climates were hindcasted to a pre-disturbance period of 1896-1925 using existing land use models and historical temperature data. Then historical fish assemblages were reconstructed using the ecological niche models. Substantial changes were noted when reconstructed fish assemblages were compared to those from the contemporary period (1981-2010. Disentangling the sometimes opposing, sometimes compounding, effects of eutrophication and climate warming was critical for understanding changes in fish assemblages. Reconstructed abundances of eutrophication-tolerant, warmwater taxa increased in prairie lakes that experienced significant eutrophication and climate warming. Eutrophication-intolerant, warmwater taxa abundance increased in forest lakes where primarily climate warming was the stressor. Coolwater fish declined in abundance in both ecoregions. Large changes in modeled abundance occurred when the effects of both climate and eutrophication operated in the same direction for some species. Conversely, the effects of climate warming and eutrophication operated in opposing directions for other species and dampened net changes in abundance. Quantifying the specific effects of climate and eutrophication will allow water resource managers to better understand how lakes have changed and provide expectations for sustainable fish assemblages in the future.

Availability of Insurance Linkage Programs in U.S. Emergency Departments

Directory of Open Access Journals (Sweden)

Mia Kanak

2014-07-01

Full Text Available Introduction: As millions of uninsured citizens who use emergency department (ED services are now eligible for health insurance under the Affordable Care Act, the ED is ideally situated to facilitate linkage to insurance. Forty percent of U.S. EDs report having an insurance linkage program. This is the first national study to examine the characteristics of EDs that offer or do not offer these programs. Methods: This was a secondary analysis of data from the National Survey for Preventive Health Services in U.S. EDs conducted in 2008-09. We compared EDs with and without insurance programs across demographic and operational factors using univariate analysis. We then tested our hypotheses using multivariable logistic regression. We also further examined program capacity and priority among the sub-group of EDs with no insurance linkage program. Results: After adjustment, ED-insurance linkage programs were more likely to be located in the West (RR= 2.06, 95% CI = 1.33 – 2.72. The proportion of uninsured patients in an ED, teaching hospital status, and public ownership status were not associated with insurance linkage availability. EDs with linkage programs also offer more preventive services (RR = 1.87, 95% CI = 1.37–2.35 and have greater social worker availability (RR = 1.71, 95% CI = 1.12–2.33 than those who do not. Four of five EDs with a patient mix of ≥25% uninsured and no insurance linkage program reported that they could not offer a program with existing staff and funding. Conclusion: Availability of insurance linkage programs in the ED is not associated with the proportion of uninsured patients served by an ED. Policy or hospital-based interventions to increase insurance linkage should first target the 27% of EDs with high rates of uninsured patients that lack adequate program capacity. Further research on barriers to implementation and cost effectiveness may help to facilitate increased adoption of insurance linkage programs. [West J

Eutrophication, microbial-sulfate reduction and mass extinctions

DEFF Research Database (Denmark)

Schobben, Martin; Stebbins, Alan; Ghaderi, Abbas

2016-01-01

to the Earth system, notably, the biogeochemical sulfur and carbon cycle. This climate warming feedback produces large-scale eutrophication on the continental shelf, which, in turn, expands oxygen minimum zones by increased respiration, which can turn to a sulfidic state by increased microbial-sulfate...

Algae, phytoplankton and eutrophication research and management ...

African Journals Online (AJOL)

The role of algal and phytoplankton research and the focus shift to cyanobacteria, because of eutrophication in South African aquatic systems, are highlighted, which indicates the different modelling and management methods that have been used and tested. Recommendations are made for future research. Keywords: ...

Evidence for the Importance of Atmospheric Nitrogen Deposition to Eutrophic Lake Dianchi, China

Science.gov (United States)

Zhan, X.; Bo, Y.; Zhou, F.; Liu, X.; Paerl, H. W.; Shen, J.; Wang, R.; Li, F. R.; Tao, S.; Yanjun, D.; Tang, X.

2017-12-01

Elevated atmospheric nitrogen (N) deposition has significantly influenced aquatic ecosystems, especially with regard to their N budgets and phytoplankton growth potentials. Compared to a considerable number of studies on oligotrophic lakes and oceanic waters, little evidence for the importance of N deposition has been generated for eutrophic lakes, even though emphasis has been placed on reducing external N inputs to control eutrophication in these lakes. Our high-resolution observations of atmospheric depositions and riverine inputs of biologically reactive N species into eutrophic Lake Dianchi (the sixth largest freshwater lake in China) shed new light onto the contribution of N deposition to total N loads. Annual N deposition accounted for 15.7% to 16.6% of total N loads under variable precipitation conditions, 2-fold higher than previous estimates (7.6%) for the Lake Dianchi. The proportion of N deposition to total N loads further increased to 27-48% in May and June when toxic blooms of the ubiquitous non-N2 fixing cyanobacteria Microcystis spp. are initiated and proliferate. Our observations reveal that reduced N (59%) contributes a greater amount than oxidized N to total N deposition, reaching 56-83% from late spring to summer. Progress toward mitigating eutrophication in Lake Dianchi and other bloom-impacted eutrophic lakes will be difficult without reductions in ammonia emissions and subsequent N deposition.

Shifts in coastal fish communities: Is eutrophication always beneficial for sticklebacks?

Science.gov (United States)

Gagnon, Karine; Gräfnings, Max; Boström, Christoffer

2017-11-01

Following declines of predatory fish, mesopredators such as sticklebacks have been linked to shifts in coastal trophic networks through both top-down (preying on mesograzers and facilitating algal blooms) and bottom-up (benefitting from eutrophicated conditions) processes. Here, we tested whether the association between eutrophication effects (filamentous algae and turbidity) and sticklebacks held true in the Finnish Archipelago Sea where predatory fish populations have remained stable. If so, sticklebacks should be more abundant in the middle archipelago, where eutrophic conditions have led to increased turbidity, higher filamentous algal loads, and decreased cover of submerged aquatic vegetation (SAV), than in the outer archipelago, where environmental conditions are better. We measured the spatial and seasonal variation of sticklebacks (three-spined Gasterosteus aculeatus and nine-spined Pungitius pungitius) in middle and outer archipelago sites, as well as environmental variables potentially affecting their abundance. Adults and juveniles of both species were more abundant in the outer than middle archipelago. The outer archipelago was characterized by greater Secchi depth throughout the summer and higher SAV cover in late summer. Secchi depth was positively correlated with stickleback abundance of both species, while SAV cover was also positively correlated in late summer. Filamentous algal cover was high in both the middle and outer archipelago, but not consistently associated with stickleback abundance throughout the summer. While sticklebacks have been thought to both contribute to, and benefit from, eutrophication, our results instead suggest that the resulting environmental changes may have adverse effects on sticklebacks, especially if predators are present. This may lead them to shift their breeding grounds and spatial distribution to less eutrophicated areas where lower turbidity and the resulting increased availability of SAV provide refuge from

Stream Macroinvertebrate Occurrence along Gradients in Organic Pollution and Eutrophication

DEFF Research Database (Denmark)

Friberg, Nikolai; Skriver, Jens; Larsen, Søren Erik

2010-01-01

We analysed a large number of concurrent samples of macroinvertebrate communities and chemical indicators of eutrophication and organic pollution [total-P, total-N, NH4-N, biological oxygen demand (BOD5)] from 594 Danish stream sites. Samples were taken over an 11-year time span as part of the Da......We analysed a large number of concurrent samples of macroinvertebrate communities and chemical indicators of eutrophication and organic pollution [total-P, total-N, NH4-N, biological oxygen demand (BOD5)] from 594 Danish stream sites. Samples were taken over an 11-year time span as part...

Effects of eutrophication and temperature on submersed rooted plants

DEFF Research Database (Denmark)

Raun, Ane-Marie Løvendahl

nutrient levels facilitate the formation of pelagic alga blooms which lead to poor light conditions (Nielsen et al., 2002). However, the lack of re‐colonization after reduced nutrient loading for Zostera marina and other seagrasses indicates that other factors influence the pattern. Sedimentation...... in combination with high temperature affect internal oxygen concentrations, growth and survival of aquatic macrophytes. Measurements of internal oxygen levels were made on several north temperate and tropical marine seagrass species exposed to a range of water column oxygen concentrations. The combined effects...... of eutrophication and temperatures were clarified for the temporal seagrass Zostera marina. Furthermore, the direct effect of sediment enrichment with labile organic matter was examined for four freshwater species with different growth strategies (isoetids: Lobelia dortmanna and Littorella uniflora, and elodeids...

Linking climate change and progressive eutrophication to incidents ...

African Journals Online (AJOL)

PRECIOUS

2009-11-02

Nov 2, 2009 ... 1CSIR Natural Resources and the Environment, P. O. Box 395, Pretoria, ZA0001, South Africa. ... be greatly accelerated by human intervention in the natural ..... and the prioritization of eutrophication control. Ecol. Eng. 16: ...

Eutrophication status and control strategy of Taihu Lake

Institute of Scientific and Technical Information of China (English)

Limin ZHANG; Minfang XIA; Lei ZHANG; Chun WANG; Jilai LU

2008-01-01

The water quality and eutrophication status of Taihu Lake in recent years are presented and the pollution trends are analyzed. It is shown that because of unreas-onable industrial structures, pollution discharge per GDP is high within the Taihu basin, and the pollution discharge from point and-non-point sources exceed the basin's environmental carrying capacity. Especially, excessive pollutants containing nitrgogen and phosphorus are being discharged. Moreover, eutrophication may also result from internal pollution sources such as the release of nutrient elements from sediment. All these factors have resulted in-the water quality deterioration of Taihu Lake. To solve this environmental problem, possible con-trol strategies are summarized, including the control of internal pollution sources and inflow-river pollution, eco-logical restoration and reconstruction of the degraded lakeside zone ecosystem, clean water diversion, dredging, and manual algae removal.

Methods of eutrophication assessment in the context of the water framework directive: Examples from the Eastern Mediterranean coastal areas

Science.gov (United States)

Pavlidou, Alexandra; Simboura, Nomiki; Rousselaki, Eleni; Tsapakis, Manolis; Pagou, Kalliopi; Drakopoulou, Paraskevi; Assimakopoulou, Georgia; Kontoyiannis, Harilaos; Panayotidis, Panayotis

2015-10-01

A set of methodological tools were tested in order to assess the eutrophication quality of selected coastal areas in Eastern Mediterranean Sea, Greece, in the context of the Water Framework Directive under various anthropogenic pressures. Three, five-step tools, namely, TRIX, chlorophyll-a (chl-a) biomass classification scheme, and eutrophication index (E.I.) were applied in oligotrophic waters for (a) the whole water column and (b) the euphotic zone. The relationship among the eutrophication assessment indices and the ecological quality status (EcoQ) assessment indices for benthic macroinvertebrates (BENTIX index) and macroalgae (ecological evaluation index-EEIc) was also explored. Agricultural activities and mariculture are the pressures mostly related to the eutrophication assessment of the selected Greek coastal water bodies. Chl-a proved to be the criterion with the best overall correlation with the EcoQ indices, while TRIX with the lowest. Moreover, among the eutrophication indices, E.I. showed better overall agreement with BENTIX showing that probably it reflects the indirect relation of macroinvertebrates with water eutrophication in a better way. Among the eutrophication indices used, TRIX rather overestimated the eutrophication status of the selected coastal areas. The first stage of eutrophication was reflected more efficiently using E.I. than TRIX, but E.I. seems to be a rather sensitive index. A future modification of the high to good boundary of E.I. may be needed in order to demonstrate the high status of the relatively undisturbed Greek coastal sites.

Metal accumulation by submerged macrophytes in eutrophic lakes at the watershed scale.

Science.gov (United States)

Xing, Wei; Wu, Haoping; Hao, Beibei; Liu, Guihua

2013-10-01

Metal concentrations (Al, Ba, Ca, K, Li, Mg, Na, Se, Sr and Ti) in submerged macrophytes and corresponding water and sediments were studied in 24 eutrophic lakes along the middle and lower reaches of the Yangtze River (China). Results showed that these eutrophic lakes have high metal concentrations in both water and sediments because of human activities. Average concentrations of Al and Na in tissues of submerged macrophytes were very high in sampled eutrophic lakes. By comparison, Ceratophyllum demersum and Najas marina accumulated more metals (e.g. Ba, Ca, K, Mg, Na, Sr and Ti). Strong positive correlations were found between metal concentrations in tissues of submerged macrophytes, probably because of co-accumulation of metals. The concentrations of Li, Mg, Na and Sr in tissues of submerged macrophytes significantly correlated with their corresponding water values, but not sediment values.

Laboratory assessment of bioleaching of shallow eutrophic sediment by immobilized photosynthetic bacteria.

Science.gov (United States)

Sun, Shiyong; Fan, Shenglan; Shen, Kexuan; Lin, Shen; Nie, Xiaoqin; Liu, Mingxue; Dong, Faqin; Li, Jian

2017-10-01

Eutrophic sediment is a serious problem in ecosystem restoration, especially in shallow lake ecosystems. We present a novel bioleaching approach to treat shallow eutrophic sediment with the objective of preventing the release of nitrate, phosphate, and organic compounds from the sediment to the water column, using porous mineral-immobilized photosynthetic bacteria (PSB). Bioactivity of bacteria was maintained during the immobilization process. Immobilized PSB beads were directly deposited on the sediment surface. The deposited PSB utilized pollutants diffused from the sediment as a nutritive matrix for growth. We evaluated the effects of light condition, temperature, initial pH, amount of PSB beads, and frequency of addition of PSB beads for contaminant removal efficiency during bioleaching operations. The presented study indicated that immobilized PSB beads using porous minerals as substrates have considerable application potential in bioremediation of shallow eutrophic lakes.

An Innovative Way of Utilizing Wave Energy to Counteract Eutrophication and Hypoxia

DEFF Research Database (Denmark)

Margheritini, Lucia; Claeson, Lennart

2011-01-01

One of the most urgent environmental issues in 415 coastal systems worldwide is eutrophication and hypoxia. Cause of eutrophication is the rapid increase in intensive agricultural practices, industrial activities, and population growth which together have increased nitrogen and phosphorus flows...... in the environment. This is a major problem in the Baltic Sea. The present study introduces the Wave-Energized Baltic Aeration Pump (WEBAP). This is one floating overtopping device that uses the collected overtopping water to oxygenate the sea bottom in areas suffering from eutrophication. This is done by using...... the driving head of the overtopping water temporarily stored in the reservoir flowing out through a long vertical pipe leading close to the bottom of the sea. The necessary amounts of oxygen and corresponding overtopping volumes in order to have a positive impact in a damaged environment have been considered...

From Greenland to green lakes: Cultural eutrophication and the loss of benthic pathways in lakes

DEFF Research Database (Denmark)

Vadeboncoeur, Y.; Jeppesen, E.; Zanden, M. J. V.

2003-01-01

Benthic community responses to lake eutrophication are poorly understood relative to pelagic responses. We compared phytoplankton and periphyton productivity along a eutrophication gradient in Greenland, U.S., and Danish lakes. Phytoplankton productivity increased along the phosphorus gradient (t...

Impact of a wastewater treatment plant on microbial community composition and function in a hyporheic zone of a eutrophic river

NARCIS (Netherlands)

Atashgahi, S.; Aydin, R.; Rocha Dimitrov, M.; Sipkema, D.; Hamonts, K.; Lahti, Leo; Maphosa, F.; Kruse, T.; Saccenti, E.; Springael, D.; Dejonghe, W.; Smidt, H.

2015-01-01

The impact of the installation of a technologically advanced wastewater treatment plant (WWTP) on the benthic microbial community of a vinyl chloride (VC) impacted eutrophic river was examined two years before, and three and four years after installation of the WWTP. Reduced dissolved organic carbon

Mother/child bond in mothers of overweight and eutrophic children: depression and socioeconomic factors

Directory of Open Access Journals (Sweden)

Patricia Vieira Spada

2011-03-01

Full Text Available Objective: To verify the presence of depression, age, level of schooling, occupation, marital status, number of children and nutritional status (maternal and of the child in mothers of overweight and eutrophic children and relate the data to mother/child bonding. Methods: A total of 120 mothers of children aged up to 10 years participated; 30 of them were overweight and 30 were eutrophic (low-income bracket; 30 were overweight and 30 eutrophic (high-income bracket. The control group was composed of eutrophic children paired according to sex, age, level of schooling, and social condition. Data collection was made through interviews. The assessment instruments were: Mother/Child Bonding Assessment Protocol and Beck Depression Inventory. The nutritional classification was defined by calculation of the body mass index, as per the curves of the World Health Organization. For statistics, McNemar, χ2, and Fisher’s exact tests were used. A 5% level of rejection of the null hypothesis was set. Results: There was no significant result between mother/child bonding and the variables studied, or between the presence of depression and level of schooling, marital status, occupation, and maternal nutritional status. Nevertheless, mothers of eutrophic children (high-income bracket showed less depression than mothers of eutrophic children (low-income bracket. Mothers with three or more children displayed more depression than mothers with less than three children. Mothers under 30 years of age showed more depression than mothers aged 30 years or older. Conclusion: There was no significant result between mother/child bonding and the variables studied, but the bond was compromised in all mothers of the sample. There was a significant result regarding the presence of depression.

Estimating time-varying RSA to examine psychophysiological linkage of marital dyads.

Science.gov (United States)

Gates, Kathleen M; Gatzke-Kopp, Lisa M; Sandsten, Maria; Blandon, Alysia Y

2015-08-01

One of the primary tenets of polyvagal theory dictates that parasympathetic influence on heart rate, often estimated by respiratory sinus arrhythmia (RSA), shifts rapidly in response to changing environmental demands. The current standard analytic approach of aggregating RSA estimates across time to arrive at one value fails to capture this dynamic property within individuals. By utilizing recent methodological developments that enable precise RSA estimates at smaller time intervals, we demonstrate the utility of computing time-varying RSA for assessing psychophysiological linkage (or synchrony) in husband-wife dyads using time-locked data collected in a naturalistic setting. © 2015 Society for Psychophysiological Research.

Effects of land use changes on eutrophication indicators in five coastal lagoons of the Southwestern Atlantic Ocean

Science.gov (United States)

Rodríguez-Gallego, Lorena; Achkar, Marcel; Defeo, Omar; Vidal, Leticia; Meerhoff, Erika; Conde, Daniel

2017-03-01

Five catchment areas in Uruguay were selected to conduct a nutrient exportation analysis and to evaluate the effects of current land use on the eutrophication of coastal lagoons. Satellite images and national agriculture censuses were used for a quantitative analysis of land use changes from 1974 to 2005, and a nutrient export coefficient approximation was used to determine long-term changes in annual loads. Several eutrophication indicators (water, sediment and autotrophic communities) were assessed seasonally in the lagoon basins during 2005 and 2006. The areal annual load of nutrients exported to the lagoons increased over time. Population and extensive livestock ranching were the most important nutrient sources, while agriculture is increasing in importance. Buffer effects of riparian forests on eutrophication indicators were observed in contrast to the wetlands surrounding the lagoons, which seem to be acting as a source of nutrients. Catchment size was inversely related to most eutrophication indicators. Afforestation and agriculture were found not to directly impact eutrophication indicators, however, catchments with larger agricultural areas showed higher concentrations of suspended solids, which may indicate the export of particulate nutrients. Salinity was inversely related to most eutrophication indicators, suggesting that the manipulation of the sand bar of the lagoons is a critical management issue. Sediment-related eutrophication indicators were more sensitive to changes in land uses and covers, in contrast with the more variable water column indicators, suggesting their potential use as enduring indicators. This research provides a rapid and integral assessment for qualitatively linking catchment changes with eutrophication indicators in coastal environments, which can easily be replicated to track pollutants in locations that lack standardized monitoring programs needed for more complex catchment modeling approaches.

Eutrophication decrease: Phosphate adsorption processes in presence of nitrates.

Science.gov (United States)

Boeykens, Susana P; Piol, M Natalia; Samudio Legal, Lisa; Saralegui, Andrea B; Vázquez, Cristina

2017-12-01

Eutrophication causes aquatic environment degradation as well as serious problems for different purposes of water uses. Phosphorus and nitrogen, mainly as phosphate and nitrate respectively, are considered responsible for eutrophication degradation. The focus of this work was the study of adsorption processes for decreasing phosphate and nitrate concentrations in bi-component aqueous systems. Dolomite and hydroxyapatite were selected as low-cost adsorbents. Obtained results showed that both adsorbents have high capacity for phosphate adsorption which the presence of nitrate does not modify. Hydroxyapatite proved to be the most efficient adsorbent, however, it showed a low percentage of desorption and few possibilities of reuse. Dolomite, on the other hand, allows a desorption of the adsorbed material that favours its reuse. Copyright © 2017 Elsevier Ltd. All rights reserved.

Microbial Community Structure in Relation to Water Quality in a Eutrophic Gulf of Mexico Estuary

Science.gov (United States)

Weeks Bay is a shallow, microtidal, eutrophic sub-estuary of Mobile Bay, AL. High watershed nutrient inputs to the estuary contribute to a eutrophic condition characterized by frequent summertime diel-cycling hypoxia and dissolved oxygen (DO) oversaturation. Spatial and seasonal ...

Lake eutrophication and its implications for organic carbon sequestration in Europe.

Science.gov (United States)

Anderson, N J; Bennion, H; Lotter, A F

2014-09-01

The eutrophication of lowland lakes in Europe by excess nitrogen (N) and phosphorus (P) is severe because of the long history of land-cover change and agricultural intensification. The ecological and socio-economic effects of eutrophication are well understood but its effect on organic carbon (OC) sequestration by lakes and its change overtime has not been determined. Here, we compile data from ~90 culturally impacted European lakes [~60% are eutrophic, Total P (TP) >30 μg P l(-1) ] and determine the extent to which OC burial rates have increased over the past 100-150 years. The average focussing corrected, OC accumulation rate (C ARFC ) for the period 1950-1990 was ~60 g C m(-2) yr(-1) , and for lakes with >100 μg TP l(-1) the average was ~100 g C m(-2) yr(-1) . The ratio of post-1950 to 1900-1950 C AR is low (~1.5) indicating that C accumulation rates have been high throughout the 20th century. Compared to background estimates of OC burial (~5-10 g C m(-2) yr(-1) ), contemporary rates have increased by at least four to fivefold. The statistical relationship between C ARFC and TP derived from this study (r(2) = 0.5) can be used to estimate OC burial at sites lacking estimates of sediment C-burial. The implications of eutrophication, diagenesis, lake morphometry and sediment focussing as controls of OC burial rates are considered. A conservative interpretation of the results of the this study suggests that lowland European meso- to eutrophic lakes with >30 μg TP l(-1) had OC burial rates in excess of 50 g C m(-2) yr(-1) over the past century, indicating that previous estimates of regional lake OC burial have seriously underestimated their contribution to European carbon sequestration. Enhanced OC burial by lakes is one positive side-effect of the otherwise negative impact of the anthropogenic disruption of nutrient cycles. © 2014 John Wiley & Sons Ltd.

Alcian blue-stained particles in a eutrophic lake

DEFF Research Database (Denmark)

Worm, J.; Søndergaard, Morten

1998-01-01

We used a neutral solution of Alcian Blue to stain transparent particles in eutrophic Lake Frederiksborg Slotss0, Denmark. Alcian Blue-stained particles (ABSP) appeared to be similar to the so-called transparent exopolymer particles (TEP) identified with an acidic solution of Alcian Blue. Our...

A bibliometric review of nitrogen research in eutrophic lakes and reservoirs.

Science.gov (United States)

Yao, Xiaolong; Zhang, Yunlin; Zhang, Lu; Zhou, Yongqiang

2018-04-01

The global application of nitrogen is far greater than phosphorus, and it is widely involved in the eutrophication of lakes and reservoirs. We used a bibliometric method to quantitatively and qualitatively evaluate nitrogen research in eutrophic lakes and reservoirs to reveal research developments, current research hotspots, and emerging trends in this area. A total of 2695 articles in the past 25years from the online database of the Scientific Citation Index Expended (SCI-Expanded) were analyzed. Articles in this area increased exponentially from 1991 to 2015. Although the USA was the most productive country over the past 25years, China achieved the top position in terms of yearly publications after 2010. The most active keywords related to nitrogen in the past 25years included phosphorus, nutrients, sediment, chlorophyll-a, carbon, phytoplankton, cyanobacteria, water quality, modeling, and stable isotopes, based on analysis within 5-year intervals from 1991 to 2015 as well as the entire past 25years. In addition, researchers have drawn increasing attention to denitrification, climate change, and internal loading. Future trends in this area should focus on: (1) nutrient amounts, ratios, and major nitrogen sources leading to eutrophication; (2) nitrogen transformation and the bioavailability of different nitrogen forms; (3) nitrogen budget, mass balance model, control, and management; (4) ecosystem responses to nitrogen enrichment and reduction, as well as the relationships between these responses; and (5) interactions between nitrogen and other stressors (e.g., light intensity, carbon, phosphorus, toxic contaminants, climate change, and hydrological variations) in terms of eutrophication. Copyright © 2017. Published by Elsevier B.V.

Eutrophication: Present reality and future challenges for South Africa ...

African Journals Online (AJOL)

During the past 40 years, eutrophication has become an increasing threat to the usability ... biomanipulation of the food web, accurate prediction of cyanobacterial growth ... Continued monitoring and reporting of trophic status are essential to ...

Prospective Linkages between Peer Victimization and Externalizing Problems in Children: A Meta-Analysis

NARCIS (Netherlands)

Reijntjes, A.; Kamphuis, J.H.; Prinzie, P.; Boelen, P.A.; van der Schoot, M.; Telch, M.J.

2011-01-01

Previous meta-analytic research has shown both concurrent and prospective linkages between peer victimization and internalizing problems in youth. However, the linkages between peer victimization and externalizing problems over time have not been systematically examined, and it is therefore unknown

Top-down control as important as nutrient enrichment for eutrophication effects in North Atlantic coastal ecosystems

NARCIS (Netherlands)

Ostman, Orjan; Eklof, Johan; Eriksson, Britas Klemens; Olsson, Jens; Moksnes, Per-Olav; Bergstrom, Ulf

Seagrass and seaweed habitats constitute hotspots for diversity and ecosystem services in coastal ecosystems. These habitats are subject to anthropogenic pressures, of which eutrophication is one major stressor. Eutrophication favours fast-growing ephemeral algae over perennial macroalgae and

Acidity removal from Lusatian mining lakes through eutrophication

Energy Technology Data Exchange (ETDEWEB)

Fyson, A.; Nixdorf, B.; Steinberg, C.F.W. [Brandenburg University of Technology, Cottbus (Germany)

2001-07-01

The flooded, disused lignite pits of Lusatia in north-eastern Germany are characterised by low pH (2 - 3.5) and high concentrations of iron which contribute to high acidity. Removal of acidity from these lakes using low-cost, environmentally acceptable technologies is being investigated. One option is the enhancement of biologically mediated, alkalinity generating processes, through controlled eutrophication to sustainably increase nutrient cycling and carbon inputs. Although the primary production of these waters is potentially high and diverse algae grow in these lakes, the growth of autotrophic organisms is usually limited by extremely low concentrations of P and inorganic C. Theoretical considerations and laboratory mesocosm results are used to demonstrate the potential productivity of these acid waters and the direct and indirect role of controlled eutrophication in removing acidity. Such data are being used to generate self-sustaining, environmentally friendly, affordable remediation strategies to develop these lakes for recreation and wildlife. 14 refs., 1 tab.

Carbon and nitrogen burial in a plateau lake during eutrophication and phytoplankton blooms.

Science.gov (United States)

Huang, Changchun; Zhang, Linlin; Li, Yunmei; Lin, Chen; Huang, Tao; Zhang, Mingli; Zhu, A-Xing; Yang, Hao; Wang, Xiaolei

2018-03-01

Organic carbon (OC) buried in lake sediment is an important component of the global carbon cycle. The impact of eutrophication on OC burial in lakes should be addressed due to worldwide lake eutrophication. Fourteen 210 Pb- and 137 Cs-dated sediment cores taken in Dianchi Lake (China) in August 2006 (seven cores) and July 2014 (seven cores) were analyzed to evaluate the response of the organic carbon accumulation rate (OCAR) to eutrophication and algal blooms over the past hundred years. The mean value of OCAR before eutrophication occurred in 1979, 16.62±7.53 (mean value±standard deviation), increased to 54.33±27.29gm -2 yr -1 after eutrophication. It further increased to 61.98±28.94gm -2 yr -1 after algal blooms occurred (1989). The accumulation rate of organic nitrogen (ONAR) is coupled with OCAR. The high loss rate of OC and organic nitrogen (ON) leads to a long-term burial efficiency of only 10% and 5% of OC and ON. However, this efficiency can still lead to an increase in OCAR by a factor of 4.55 during algal blooms in Dianchi Lake. Dianchi Lake stored 1.26±0.32 Tg carbon and 0.071±0.018 Tg nitrogen, including 0.94±0.23 Tg OC and 0.32±0.14 Tg inorganic carbon, 0.066±0.018 Tg ON, 0.002±0.001 Tg nitrate nitrogen (NO 3 -N) and 0.003±0.001 Tg ammonium nitrogen (NH 4 -N) between 1900 and 2012. Copyright © 2017 Elsevier B.V. All rights reserved.

Eutrophication and cyanobacteria in South Africa's standing water bodies: A view from space

OpenAIRE

Matthews, Mark W.; Bernard, Stewart

2015-01-01

Satellite remote sensing can make a significant contribution to monitoring water quality in South African standing water bodies. Eutrophication, defined as enrichment by nutrients, and toxin-producing cyanobacteria (blue-green algae) blooms pose a significant threat to the quality of South African surface water bodies. The status and trends of chlorophyll a (chl-a, a proxy for eutrophication), cyanobacterial blooms and cyanobacterial surface scum were determined for South Africa’s 50 largest ...

A pantograph linkage

International Nuclear Information System (INIS)

Cole, G.V.

1982-01-01

A pantograph linkage is actuated by two linear actuators, pivotally connected together at the linkage. The displacement of the actuators is monitored by rectilinear potentiometers to provide feedback signals to a microprocessor which also receives input signals related to a required movement of a slave end of the linkage. In response to these signals, the microprocessor provides signals to control the displacement of the linear actuators to effect the required movement of the slave end. The movement of the slave end might be straightline in a substantially horizontal or vertical direction. (author)

Could Methane Oxidation in Lakes Be Enhanced by Eutrophication?

Science.gov (United States)

Van Grinsven, S.; Villanueva, L.; Harrison, J.; S Sinninghe Damsté, J.

2017-12-01

Climate change and eutrophication both affect aquatic ecosystems. Eutrophication is caused by high nutrient inputs, leading to algal blooms, oxygen depletion and disturbances of the natural balances in aquatic systems. Methane, a potent greenhouse gas produced biologically by anaerobic degradation of organic matter, is often released from the sediments of lakes and marine systems to overlying water and the atmosphere. Methane oxidation, a microbial methane consumption process, can limit methane emission from lakes and reservoirs by 50-80%. Here, we studied methane oxidation in a seasonally stratified reservoir: Lacamas Lake in Washington, USA. We found this lake has a large summer storage capacity of methane in its deep water layer, with a very active microbial community capable of oxidizing exceptionally high amounts of methane. The natural presence of terminal electron acceptors is, however, too low to support these high potential rates. Addition of eutrophication-related nutrients such as nitrate and sulfate increased the methane removal rates by 4 to 7-fold. The microbial community was studied using 16S rRNA gene amplicon sequencing and preliminary results indicate the presence of a relatively unknown facultative anaerobic methane oxidizer of the genus Methylomonas, capable of using nitrate as an electron donor. Experiments in which anoxic and oxic conditions were rapidly interchanged showed this facultative anaerobic methane oxidizer has an impressive flexibility towards large, rapid changes in environmental conditions and this feature might be key to the unexpectedly high methane removal rates in eutrophied and anoxic watersheds.

Privacy preserving interactive record linkage (PPIRL).

Science.gov (United States)

Kum, Hye-Chung; Krishnamurthy, Ashok; Machanavajjhala, Ashwin; Reiter, Michael K; Ahalt, Stanley

2014-01-01

Record linkage to integrate uncoordinated databases is critical in biomedical research using Big Data. Balancing privacy protection against the need for high quality record linkage requires a human-machine hybrid system to safely manage uncertainty in the ever changing streams of chaotic Big Data. In the computer science literature, private record linkage is the most published area. It investigates how to apply a known linkage function safely when linking two tables. However, in practice, the linkage function is rarely known. Thus, there are many data linkage centers whose main role is to be the trusted third party to determine the linkage function manually and link data for research via a master population list for a designated region. Recently, a more flexible computerized third-party linkage platform, Secure Decoupled Linkage (SDLink), has been proposed based on: (1) decoupling data via encryption, (2) obfuscation via chaffing (adding fake data) and universe manipulation; and (3) minimum information disclosure via recoding. We synthesize this literature to formalize a new framework for privacy preserving interactive record linkage (PPIRL) with tractable privacy and utility properties and then analyze the literature using this framework. Human-based third-party linkage centers for privacy preserving record linkage are the accepted norm internationally. We find that a computer-based third-party platform that can precisely control the information disclosed at the micro level and allow frequent human interaction during the linkage process, is an effective human-machine hybrid system that significantly improves on the linkage center model both in terms of privacy and utility.

Environmental Impact Analysis of Acidification and Eutrophication Due to Emissions from the Production of Concrete

Directory of Open Access Journals (Sweden)

Tae Hyoung Kim

2016-06-01

Full Text Available Concrete is a major material used in the construction industry that emits a large amount of substances with environmental impacts during its life cycle. Accordingly, technologies for the reduction in and assessment of the environmental impact of concrete from the perspective of a life cycle assessment (LCA must be developed. At present, the studies on LCA in relation to greenhouse gas emission from concrete are being carried out globally as a countermeasure against climate change. However, the studies on the impact of the substances emitted in the concrete production process on acidification and eutrophication are insufficient. As such, assessing only a single category of environmental impact may cause a misunderstanding about the environmental friendliness of concrete. The substances emitted in the concrete production process have an impact not only on global warming but also on acidification and eutrophication. Acidification and eutrophication are the main causes of air pollution, forest destruction, red tide phenomena, and deterioration of reinforced concrete structures. For this reason, the main substances among those emitted in the concrete production process that have an impact on acidification and eutrophication were deduced. In addition, an LCA technique through which to determine the major emissions from concrete was proposed and a case analysis was carried out. The substances among those emitted in the concrete production process that are related to eutrophication were deduced to be NOx, NH3, NH4+, COD, NO3−, and PO43−. The substances among those emitted in the concrete production process that are related to acidification, were found to be NOx, SO2, H2S, and H2SO4. The materials and energy sources among those input into the concrete production process, which have the biggest impact on acidification and eutrophication, were found to be coarse aggregate and fine aggregate.

Application of Water Quality Model of Jordan River to Evaluate Climate Change Effects on Eutrophication

Science.gov (United States)

Van Grouw, B.

2016-12-01

The Jordan River is a 51 mile long freshwater stream in Utah that provides drinking water to more than 50% of Utah's population. The various point and nonpoint sources introduce an excess of nutrients into the river. This excess induces eutrophication that results in an inhabitable environment for aquatic life is expected to be exacerbated due to climate change. Adaptive measures must be evaluated based on predictions of climate variation impacts on eutrophication and ecosystem processes in the Jordan River. A Water Quality Assessment Simulation Program (WASP) model was created to analyze the data results acquired from a Total Maximum Daily Load (TMDL) study conducted on the Jordan River. Eutrophication is modeled based on levels of phosphates and nitrates from point and nonpoint sources, temperature, and solar radiation. It will simulate the growth of phytoplankton and periphyton in the river. This model will be applied to assess how water quality in the Jordan River is affected by variations in timing and intensity of spring snowmelt and runoff during drought in the valley and the resulting effects on eutrophication in the river.

Current status of emerging hypoxia in a eutrophic estuary: The lower reach of the Pearl River Estuary, China

Science.gov (United States)

Qian, Wei; Gan, Jianping; Liu, Jinwen; He, Biyan; Lu, Zhongming; Guo, Xianghui; Wang, Deli; Guo, Liguo; Huang, Tao; Dai, Minhan

2018-05-01

We examine the current status of dissolved oxygen (DO) and its trend over the past 25 years in the lower Pearl River Estuary, a large eutrophic estuary located in Southern China and surrounded by large cities including Hong Kong, Shenzhen and Guangzhou. Monthly cruises conducted from April 2010 to March 2011 clearly show that DO depletion began to emerge in the bottom layer of the lower estuary off Hong Kong in June, and became fully developed in July and August when oxygen-deficient water occupied ∼1000 km2 before gradually becoming re-oxygenated in September and October. The development of the low oxygen zone was closely coupled with phytoplankton blooms in the surface water, which was supersaturated with respect to DO suggesting the importance of autochthonous organic matter in fueling bottom DO consumption after settling through the pycnocline. Long-term monitoring data collected in the study area adjacent to Hong Kong by the Hong Kong Environmental Protection Department showed a decreasing trend of ∼2 ± 0.9 μmol kg-1 yr-1 in the annual minimum DO concentration in bottom water over the past 25 years. Associated with the decrease in DO was an increase in the annual maximum surface concentration of dissolved inorganic nitrogen (DIN) at a rate of ∼1.4 ± 0.3 μmol kg-1 yr-1, suggesting again that eutrophication is the most plausible driver of oxygen deficiency in this region. Therefore, our monthly cruises, along with the decadal monitoring data, reveal a large low oxygen zone, likely developing into a large hypoxic zone driven primarily by anthropogenic eutrophication. This new development suggests environmental stressors such as eutrophication may have a cascading effect, with important and expensive consequences for the regional environment.

Management of eutrophication in Lake De Kuil (The Netherlands) using combined flocculant - lanthanum modified bentonite treatment

NARCIS (Netherlands)

Waaijen, G.; Oosterhout, van F.; Douglas, G.C.; Lurling, M.F.L.L.W.

2016-01-01

Eutrophication of Lake De Kuil (The Netherlands, 6.7 ha, maximum depth 9 m) has frequently caused cyanobacterial blooms resulting in swimming bans or the issue of water quality warnings during summer. The eutrophication was mainly driven by sediment phosphorus (P)-release. The external P-loading was

Hulun Lake's ecological health and evaluation of its' eutrophication

Science.gov (United States)

Li, W.; Yang, W.; Wang, X.; Huang, J.; Sun, B.; Li, X.

2013-12-01

Hulun Lake is the largest lake in the north of china. The special geological location determines its important position in regional environmental protection. In terms of Hulun Lake's current situation, this paper chooses the indexes of lake system, lake structure and lake condition. Based on the calculation of these indexes and related theory , the evaluation standards of Hulun Lake's ecological healthy system are worked out. The author used Analytic Hierarchy Process to determine the weight of each indicator layer and criteria layer, and then applied fuzzy-pattern recognition model to calculate, finally, identifying the status of Hulun Lake according to the degrees of all levels. At the same time, the author used an integrated nutrition state index method to do the eutrophication assessment. Evaluation results show that the current status of Hulun Lake is healthy and it is in the moderate level of eutrophication.

SNP frequency, haplotype structure and linkage disequilibrium in elite maize inbred lines

Directory of Open Access Journals (Sweden)

Smith Oscar

2002-10-01

Full Text Available Abstract Background Recent studies of ancestral maize populations indicate that linkage disequilibrium tends to dissipate rapidly, sometimes within 100 bp. We set out to examine the linkage disequilibrium and diversity in maize elite inbred lines, which have been subject to population bottlenecks and intense selection by breeders. Such population events are expected to increase the amount of linkage disequilibrium, but reduce diversity. The results of this study will inform the design of genetic association studies. Results We examined the frequency and distribution of DNA polymorphisms at 18 maize genes in 36 maize inbreds, chosen to represent most of the genetic diversity in U.S. elite maize breeding pool. The frequency of nucleotide changes is high, on average one polymorphism per 31 bp in non-coding regions and 1 polymorphism per 124 bp in coding regions. Insertions and deletions are frequent in non-coding regions (1 per 85 bp, but rare in coding regions. A small number (2–8 of distinct and highly diverse haplotypes can be distinguished at all loci examined. Within genes, SNP loci comprising the haplotypes are in linkage disequilibrium with each other. Conclusions No decline of linkage disequilibrium within a few hundred base pairs was found in the elite maize germplasm. This finding, as well as the small number of haplotypes, relative to neutral expectation, is consistent with the effects of breeding-induced bottlenecks and selection on the elite germplasm pool. The genetic distance between haplotypes is large, indicative of an ancient gene pool and of possible interspecific hybridization events in maize ancestry.

Aquatic macrophyte community varies in urban reservoirs with different degrees of eutrophication

Directory of Open Access Journals (Sweden)

Suelen Cristina Alves da Silva

2014-06-01

Full Text Available AIM: Investigate spatial and temporal variation in the aquatic macrophyte community in four urban reservoirs located in Curitiba metropolitan region, Brazil. We tested the hypothesis that aquatic macrophyte community differ among reservoirs with different degrees of eutrophication. METHODS: The reservoirs selected ranged from oligotrophic/mesotrophic to eutrophic. Sampling occurred in October 2011, January 2012 and June 2012. Twelve aquatic macrophytes stands were sampled at each reservoir. Species were identified and the relative abundance of aquatic macrophytes was estimated. Differences among reservoirs and over sampling periods were analyzed: i through two‑way ANOVAs considering the stand extent (m and the stand biodiversity - species richness, evenness, Shannon-Wiener index and beta diversity (species variation along the aquatic macrophyte stand; and ii through PERMANOVA considering species composition. Indicator species that were characteristic for each reservoir were also identified. RESULTS: The aquatic macrophyte stand extent varied among reservoirs and over sampling periods. Species richness showed only temporal variation. On the other hand, evenness and Shannon-Wiener index varied only among reservoirs. The beta diversity of macrophyte stands did not vary among reservoirs or over time, meaning that species variability among aquatic macrophyte stands was independent of the stand extent and reservoir eutrophication. Community composition depended on the reservoir and sampling period. CONCLUSIONS: Our results support our initial expectation that reservoirs of different degrees of eutrophication have different aquatic macrophyte communities. As a consequence, each reservoir had particular indicator species. Therefore, monitoring and management efforts must be offered for each reservoir individually.

The Potential Impacts of Climate Change Factors on Freshwater Eutrophication: Implications for Research and Countermeasures of Water Management in China

Directory of Open Access Journals (Sweden)

Rui Xia

2016-03-01

Full Text Available Water eutrophication has become one of the most serious aquatic environmental problems around the world. More and more research has indicated climate change as a major natural factor that will lead to the acceleration of eutrophication in rivers and lakes. However, understanding the mechanism of climate change’s effect on water eutrophication is difficult due to the uncertainties caused by its complex, non-linear process. There is considerable uncertainty about the magnitude of future temperature changes, and how these will drive eutrophication in water bodies at regional scales under the effect of human activities. This review collects the existing international and domestic literature from the last 10 years, discussing the most sensitive factors of climate change (i.e., temperature, precipitation, wind, and solar radiation and analyzing their interaction with water eutrophication. Case studies of serious eutrophication and algal bloom problems in China are discussed to further demonstrate the conclusion. Finally, adaptation countermeasures and related implications are proposed in order to foster the development of sustainability strategies for water management in China.

Ocean acidification: One potential driver of phosphorus eutrophication.

Science.gov (United States)

Ge, Changzi; Chai, Yanchao; Wang, Haiqing; Kan, Manman

2017-02-15

Harmful algal blooms which may be limited by phosphorus outbreak increases currently and ocean acidification worsens presently, which implies that ocean acidification might lead to phosphorus eutrophication. To verify the hypothesis, oxic sediments were exposed to seawater with different pH 30days. If pH was 8.1 and 7.7, the total phosphorus (TP) content in sediments was 1.52±0.50 and 1.29±0.40mg/g. The inorganic phosphorus (IP) content in sediments exposed to seawater with pH8.1 and 7.7 was 1.39±0.10 and 1.06±0.20mg/g, respectively. The exchangeable phosphorus (Ex-P) content in sediments was 4.40±0.45 and 2.82±0.15μg/g, if seawater pH was 8.1 and 7.7. Ex-P and IP contents in oxic sediments were reduced by ocean acidification significantly (pocean acidification was one potential facilitator of phosphorus eutrophication in oxic conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Genome scan for linkage to asthma using a linkage disequilibrium-lod score test.

Science.gov (United States)

Jiang, Y; Slager, S L; Huang, J

2001-01-01

We report a genome-wide linkage study of asthma on the German and Collaborative Study on the Genetics of Asthma (CSGA) data. Using a combined linkage and linkage disequilibrium test and the nonparametric linkage score, we identified 13 markers from the German data, 1 marker from the African American (CSGA) data, and 7 markers from the Caucasian (CSGA) data in which the p-values ranged between 0.0001 and 0.0100. From our analysis and taking into account previous published linkage studies of asthma, we suggest that three regions in chromosome 5 (around D5S418, D5S644, and D5S422), one region in chromosome 6 (around three neighboring markers D6S1281, D6S291, and D6S1019), one region in chromosome 11 (around D11S2362), and two regions in chromosome 12 (around D12S351 and D12S324) especially merit further investigation.

Comprehensive Study Of Duckweed Cultivation And Growth Conditions Under Controlled Eutrophication

Directory of Open Access Journals (Sweden)

Bartošová Alica

2015-06-01

Full Text Available The paper discussed the issue of eutrophication. The most conspicuous effect of eutrophication is the creation of dense blooms of noxious, foul-smelling phytoplankton that reduce water clarity and harm water quality. Nutrient concentration, temperature and pH of the water largely influence the growth rate and composition of duckweed in general, but it can be said that the temperature and solar irradiation are the most important factors. In order to compare the rate of biomass increase of duckweed biomass in natural conditions and in a laboratory grown sample was analysed by spectrophotometric methods in UV/VIS region (Spectrophotometer GENESYSTM for the selected nutrients such as ammonium, ammonium nitrogen, nitrite, nitrate, and phosphate.

VT Wildlife Linkage Habitat

Data.gov (United States)

Vermont Center for Geographic Information — (Link to Metadata) The Wildlife Linkage Habitat Analysis uses landscape scale data to identify or predict the location of potentially significant wildlife linkage...

Decade-long time delays in nutrient and plant species dynamics during eutrophication and re-oligotrophication of Lake Fure 1900–2015

DEFF Research Database (Denmark)

Sand-Jensen, Kaj; Bruun, Hans Henrik; Båstrup-Spohr, Lars

2017-01-01

Fure, Denmark, spanning the transformation from pristine environmental conditions in the early 1900s through a period (1920–1970) of eutrophication – from accelerating sewage input of phosphorus (P) – and subsequent re-oligotrophication after sewage cleaning (1970–2015). We examine time delays between...... sediment release. Fifty years of eutrophication led to a reduction in aquatic macrophyte richness from 36 species to 12. Species’ responses were closely related to their growth strategy and depth distribution. Deep-growing mosses, charophytes and short angiosperms disappeared, while tall angiosperms...... in species dominance takes longer than colonization by new species. Synthesis. Time delays of P concentrations, water clarity and macrophyte richness and composition were long and complex. Neglecting growth strategies of species makes application of extinction debt and colonization credit concepts dubious...

Eutrophication of an Urban Forest Ecosystem: Causes and Effects

Science.gov (United States)

Bednova, O. V.; Kuznetsov, V. A.; Tarasova, N. P.

2018-01-01

The combined use of methods of passive dosimetry of the status of atmospheric air, phytoindication, and cartographic visualization of data made it possible to elaborate and substantiate approaches to evaluation of the effect of atmospheric air contamination on the eutrophication of forest ecosystems under urban conditions.

Eutrophication in the Yunnan Plateau lakes: the influence of lake morphology, watershed land use, and socioeconomic factors.

Science.gov (United States)

Liu, Wenzhi; Li, Siyue; Bu, Hongmei; Zhang, Quanfa; Liu, Guihua

2012-03-01

Lakes play an important role in socioeconomic development and ecological balance in China, but their water quality has deteriorated considerably in recent decades. In this study, we investigated the spatial-temporal variations of eutrophication parameters (secchi depth, total nitrogen, total phosphorus, chemical oxygen demand, chlorophyll-a, trophic level index, and trophic state index) and their relationships with lake morphology, watershed land use, and socioeconomic factors in the Yunnan Plateau lakes. Results indicated that about 77.8% of lakes were eutrophic according to trophic state index. The plateau lakes showed spatial variations in water quality and could be classified into high-nutrient and low-nutrient groups. However, because watersheds were dominated by vegetation, all eutrophication parameters except chlorophyll-a showed no significant differences between the wet and dry seasons. Lake depth, water residence time, volume, and percentage of built-up land were significantly related to several eutrophication parameters. Agricultural land use and social-economic factors had no significant correlation with all eutrophication parameters. Stepwise regression analyses demonstrated that lake depth and water residence time accounted for 73.8% to 87.6% of the spatial variation of single water quality variables, respectively. Redundancy analyses indicated that lake morphology, watershed land use, and socioeconomic factors together explained 74.3% of the spatial variation in overall water quality. The results imply that water quality degradation in the plateau lakes may be mainly due to the domestic and industrial wastewaters. This study will improve our understanding of the determinants of lake water quality and help to design efficient strategies for controlling eutrophication in the plateau region.

Algal Diet of Small-Bodied Crustacean Zooplankton in a Cyanobacteria-Dominated Eutrophic Lake.

Directory of Open Access Journals (Sweden)

Ilmar Tõnno

Full Text Available Small-bodied cladocerans and cyclopoid copepods are becoming increasingly dominant over large crustacean zooplankton in eutrophic waters where they often coexist with cyanobacterial blooms. However, relatively little is known about their algal diet preferences. We studied grazing selectivity of small crustaceans (the cyclopoid copepods Mesocyclops leuckarti, Thermocyclops oithonoides, Cyclops kolensis, and the cladocerans Daphnia cucullata, Chydorus sphaericus, Bosmina spp. by liquid chromatographic analyses of phytoplankton marker pigments in the shallow, highly eutrophic Lake Võrtsjärv (Estonia during a seasonal cycle. Copepods (mainly C. kolensis preferably consumed cryptophytes (identified by the marker pigment alloxanthin in gut contents during colder periods, while they preferred small non-filamentous diatoms and green algae (identified mainly by diatoxanthin and lutein, respectively from May to September. All studied cladoceran species showed highest selectivity towards colonial cyanobacteria (identified by canthaxanthin. For small C. sphaericus, commonly occuring in the pelagic zone of eutrophic lakes, colonial cyanobacteria can be their major food source, supporting their coexistence with cyanobacterial blooms. Pigments characteristic of filamentous cyanobacteria and diatoms (zeaxanthin and fucoxanthin, respectively, algae dominating in Võrtsjärv, were also found in the grazers' diet but were generally avoided by the crustaceans commonly dominating the zooplankton assemblage. Together these results suggest that the co-occurring small-bodied cyclopoid and cladoceran species have markedly different algal diets and that the cladocera represent the main trophic link transferring cyanobacterial carbon to the food web in a highly eutrophic lake.

Impacts of marine renewable energy scheme operation on the eutrophication potential of the Severn Estuary, UK

Science.gov (United States)

Kadiri, Margaret; Kay, David; Ahmadian, Reza; Bockelmann-Evans, Bettina; Falconer, Roger; Bray, Michaela

2013-04-01

In recent years there has being growing global interest in the generation of electricity from renewable resources. Amongst these, marine energy resource is now being considered to form a significant part of the energy mix, with plans for the implementation of several marine renewable energy schemes such as barrages and tidal stream turbines around the UK in the near future. Although marine energy presents a great potential for future electricity generation, there are major concerns over its potential impacts, particularly barrages, on the hydro-environment. Previous studies have shown that a barrage could significantly alter the hydrodynamic regime and tidal flow characteristics of an estuary, with changes to sediment transport (Kadiri et al., 2012). However, changes to nutrients have been overlooked to date. Hence, considerable uncertainty remains as to how a barrage would affect the trophic status of an estuary. This is particularly important because eutrophication can lead to algal toxin production and increased mortality of aquatic invertebrates and fish populations. Therefore, this study examines the impacts of the two different modes of operation of a barrage (i.e. ebb generation and flood-ebb generation) on the eutrophication potential of the Severn Estuary using a simplified model developed by the UK's Comprehensive Studies Task Team (CSTT). The model uses a set of equations and site-specific input data to predict equilibrium dissolved nutrient concentrations, phytoplankton biomass, light-controlled phytoplankton growth rate and primary production which are compared against CSTT set standards for assessing the eutrophic status of estuaries and coastal waters. The estuary volume and tidal flushing time under the two operating modes were estimated using a hydrodynamic model and field surveys were conducted to obtain dissolved nitrate and phosphate concentrations which served as input data. The predicted equilibrium dissolved nitrate and phosphate

Design of special planar linkages

CERN Document Server

Zhao, Jing-Shan; Ma, Ning; Chu, Fulei

2013-01-01

Planar linkages play a very important role in mechanical engineering. As the simplest closed chain mechanisms, planar four-bar linkages are widely used in mechanical engineering, civil engineering and aerospace engineering.Design of Special Planar Linkages proposes a uniform design theory for planar four-bar linkages. The merit of the method proposed in this book is that it allows engineers to directly obtain accurate results when there are such solutions for the specified n precise positions; otherwise, the best approximate solutions will be found. This book discusses the kinematics and reach

Carbon accumulation and storage capacity in mangrove sediments three decades after deforestation within a eutrophic bay.

Science.gov (United States)

Pérez, A; Machado, W; Gutiérrez, D; Borges, A C; Patchineelam, S R; Sanders, C J

2018-01-01

A dated sediment core from an eutrophic mangrove area presented non-significant differences in carbon accumulation rates before (55.7±10.2gm -2 yr -1 ) and after three decades of deforestation (59.7±7.2gm -2 yr -1 ). Although eutrophication effects appear to compensate the loss of mangrove organic matter input, the results in this work show a threefold lower carbon accumulation than the global averages estimated for mangrove sediments. The effects of increasing eutrophication and enhanced sediment dry bulk density observed after deforestation (~30% higher) did not result in higher carbon stocks. Moreover, the lower TOC:OP (mangrove deforestation losses on carbon accumulation in mangrove ecosystems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bacterial communities in the sediments of Dianchi Lake, a partitioned eutrophic waterbody in China.

Directory of Open Access Journals (Sweden)

Yaohui Bai

Full Text Available Bacteria play an important role in the decomposition and cycling of a variety of compounds in freshwater aquatic environments, particularly nutrient-rich eutrophic lakes. A unique Chinese eutrophic lake--Dianchi--was selected for study because it has two separate and distinct basins, Caohai with higher organic carbon levels and Waihai with lower organic carbon levels. Sediment bacterial communities were studied in the two basins using samples collected in each season from June 2010 to March 2011. Barcoded pyrosequencing based on the 16 S rRNA gene found that certain common phyla, Proteobacteria, Bacteroidetes, Firmicutes and Chloroflexi, were dominant in the sediments from both basins. However, from the class to genus level, the dominant bacterial groups found in the sediments were distinct between the two basins. Correlation analysis revealed that, among the environmental parameters examined, total organic carbon (TOC accounted for the greatest proportion of variability in bacterial community. Interestingly, study results suggest that increasing allochthonous organic carbon could enhance bacterial diversity and biomass in the sediment. In addition, analysis of function genes (amoA and nosZ demonstrated that ammonia-oxidizing bacteria (AOB were dominant in sediments, with 99% belonging to Nitrosomonas. Denitrifying bacteria were comparatively diverse and were associated with some cultivatable bacteria.

Management of eutrophication in Lake De Kuil (The Netherlands) using combined flocculant – Lanthanum modified bentonite treatment

NARCIS (Netherlands)

Waajen, Guido; van Oosterhout, Frank; Douglas, Grant; Lürling, Miquel

2016-01-01

Abstract Eutrophication of Lake De Kuil (The Netherlands, 6.7 ha, maximum depth 9 m) has frequently caused cyanobacterial blooms resulting in swimming bans or the issue of water quality warnings during summer. The eutrophication was mainly driven by sediment phosphorus (P)-release. The external

Human-induced eutrophication maintains high parasite prevalence in breeding threespine stickleback populations.

Science.gov (United States)

Budria, Alexandre; Candolin, Ulrika

2015-04-01

Anthropogenic activities are having profound impacts on species interactions, with further consequences for populations and communities. We investigated the influence that anthropogenic eutrophication has on the prevalence of the parasitic tapeworm Schistocephalus solidus in threespine stickleback Gasterosteus aculeatus populations. We caught stickleback from four areas along the coast of Finland, and within each area from one undisturbed and one eutrophied habitat. We found the prevalence of the parasite to be lower in the eutrophied habitats at the start of the breeding season, probably because of fewer piscivorous birds that transmit the parasite. However, while the prevalence of the parasite declined across the season in the undisturbed habitat, it did less so in eutrophied habitats. We discuss different processes that could be behind the differences, such as lower predation rate on infected fish, higher food availability and less dispersal in eutrophied habitats. We found no effect of eutrophication on the proportion of infected stickleback that entered reproductive condition. Together with earlier findings, this suggests that eutrophication increases the proportion of infected stickleback that reproduce. This could promote the evolution of less parasite resistant populations, with potential consequences for the viability of the interacting parties of the host-parasite system.

Approaches and methods for eutrophication target setting in the Baltic Sea region

Energy Technology Data Exchange (ETDEWEB)

Carstensen, J.; Andersen, J.; Dromph, K. [and others

2013-06-01

This report describes the outcome of the project 'Review of the ecological targets for eutrophication of the HELCOM BSAP', also known as HELCOM TARGREV. The objectives of HELCOM TARGREV have been to revise the scientific basis underlying the ecological targets for eutrophication, placing much emphasis on providing a strengthened data and information basis for the setting of quantitative targets. The results are first of all likely to form the information basis on which decisions in regard to reviewing and if necessary revising the maximum allowable inputs (MAI) of nutrient of the Baltic Sea Action Plan, including the provisional country-wise allocation reduction targets (CART), will be made.

Eutrophication of lakes and reservoirs: A framework for making management decisions

Science.gov (United States)

Rast, W.; Holland, M.

1988-01-01

The development of management strategies for the protection of environmental quality usually involves consideration both of technical and nontechnical issues. A logical, step-by-step framework for development of such strategies is provided. Its application to the control of cultured eutrophication of lakes and reservoirs illustrates its potential usefulness. From the perspective of the policymaker, the main consideration is that the eutrophication-related water quality of a lake or reservoir can be managed for given water uses. The approach presented here allows the rational assessment of relevant water-quality parameters and establishment of water-quality goals, consideration of social and other nontechnical issues, the possibilities of public involvement in the decision-making process, and a reasonable economic analysis within a management framework.

Validation of an instrument to measure inter-organisational linkages in general practice.

Science.gov (United States)

Amoroso, Cheryl; Proudfoot, Judith; Bubner, Tanya; Jayasinghe, Upali W; Holton, Christine; Winstanley, Julie; Beilby, Justin; Harris, Mark F

2007-12-03

Linkages between general medical practices and external services are important for high quality chronic disease care. The purpose of this research is to describe the development, evaluation and use of a brief tool that measures the comprehensiveness and quality of a general practice's linkages with external providers for the management of patients with chronic disease. In this study, clinical linkages are defined as the communication, support, and referral arrangements between services for the care and assistance of patients with chronic disease. An interview to measure surgery-level (rather than individual clinician-level) clinical linkages was developed, piloted, reviewed, and evaluated with 97 Australian general practices. Two validated survey instruments were posted to patients, and a survey of locally available services was developed and posted to participating Divisions of General Practice (support organisations). Hypotheses regarding internal validity, association with local services, and patient satisfaction were tested using factor analysis, logistic regression and multilevel regression models. The resulting General Practice Clinical Linkages Interview (GP-CLI) is a nine-item tool with three underlying factors: referral and advice linkages, shared care and care planning linkages, and community access and awareness linkages. Local availability of chronic disease services has no affect on the comprehensiveness of services with which practices link, however, comprehensiveness of clinical linkages has an association with patient assessment of access, receptionist services, and of continuity of care in their general practice. The GP-CLI may be useful to researchers examining comparable health care systems for measuring the comprehensiveness and quality of linkages at a general practice-level with related services, possessing both internal and external validity. The tool can be used with large samples exploring the impact, outcomes, and facilitators of high

Validation of an instrument to measure inter-organisational linkages in general practice

Directory of Open Access Journals (Sweden)

Cheryl Amoroso

2007-11-01

Full Text Available Purpose: Linkages between general medical practices and external services are important for high quality chronic disease care. The purpose of this research is to describe the development, evaluation and use of a brief tool that measures the comprehensiveness and quality of a general practice’s linkages with external providers for the management of patients with chronic disease. In this study, clinical linkages are defined as the communication, support, and referral arrangements between services for the care and assistance of patients with chronic disease. Methods: An interview to measure surgery-level (rather than individual clinician-level clinical linkages was developed, piloted, reviewed, and evaluated with 97 Australian general practices. Two validated survey instruments were posted to patients, and a survey of locally available services was developed and posted to participating Divisions of General Practice (support organisations. Hypotheses regarding internal validity, association with local services, and patient satisfaction were tested using factor analysis, logistic regression and multilevel regression models. Results: The resulting General Practice Clinical Linkages Interview (GP-CLI is a nine-item tool with three underlying factors: referral and advice linkages, shared care and care planning linkages, and community access and awareness linkages. Local availability of chronic disease services has no affect on the comprehensiveness of services with which practices link, however comprehensiveness of clinical linkages has an association with patient assessment of access, receptionist services, and of continuity of care in their general practice. Conclusions: The GP-CLI may be useful to researchers examining comparable health care systems for measuring the comprehensiveness and quality of linkages at a general practice-level with related services, possessing both internal and external validity. The tool can be used with large samples

Efficient Record Linkage Algorithms Using Complete Linkage Clustering.

Science.gov (United States)

Mamun, Abdullah-Al; Aseltine, Robert; Rajasekaran, Sanguthevar

2016-01-01

Data from different agencies share data of the same individuals. Linking these datasets to identify all the records belonging to the same individuals is a crucial and challenging problem, especially given the large volumes of data. A large number of available algorithms for record linkage are prone to either time inefficiency or low-accuracy in finding matches and non-matches among the records. In this paper we propose efficient as well as reliable sequential and parallel algorithms for the record linkage problem employing hierarchical clustering methods. We employ complete linkage hierarchical clustering algorithms to address this problem. In addition to hierarchical clustering, we also use two other techniques: elimination of duplicate records and blocking. Our algorithms use sorting as a sub-routine to identify identical copies of records. We have tested our algorithms on datasets with millions of synthetic records. Experimental results show that our algorithms achieve nearly 100% accuracy. Parallel implementations achieve almost linear speedups. Time complexities of these algorithms do not exceed those of previous best-known algorithms. Our proposed algorithms outperform previous best-known algorithms in terms of accuracy consuming reasonable run times.

North-South Business Linkages

DEFF Research Database (Denmark)

Sørensen, Olav Jull; Kuada, John

2006-01-01

Based on empirical studies of linkages between TNCs and local firms in India, Malaysia, Vietnam, Ghana and South Africa, five themes are discussed and related to present theoretical perspectives. The themes are (1) Linakge Governance; (2) Globalisation and the dynamics in developing countries (the...... TNC-driven markets in developing countries); (3) The upgrading impact of FDI; (4) Non-equity linkages as a platform for business development, and (5) The learning perspective on international business linakges. The chapter offers at the end a three-dimanional model for impacts of business linkages....

Research of processes of eutrophication of Teteriv river reservoir based on neural networks mass

Directory of Open Access Journals (Sweden)

Yelnikova T.A.

2016-12-01

Full Text Available Methods of process control of eutrophication in water are based on water sampling, handling them in the laboratory and calculation of indexes of pond ecosystem. However, these methods have some significant drawbacks associated with using manual labor. The method of determining of the geometric parameters of phytoplankton through the use of neural networks for processing water samples is developed. Due to this method eutrophic processes of reservoirs of river Teteriv are investigated. A comparative analysis of eutrophic processes of reservoirs "Denyshi" and “Vidsichne” intake during 2014-2015 years are given. The differences between qualitative and quantitative composition of phytoplankton algae in two reservoirs of the river Teteriv used for water supply of Zhitomir city area are found out. The influence of exogenous and endogenous factors on the expansion of phytoplankton is researched. Research results can be used for monitoring and forecasting of ecological state of water for household purposes, used for water supply of cities.

Eutrophication and warming effects on long-term variation of zooplankton in Lake Biwa

Directory of Open Access Journals (Sweden)

C. H. Hsieh

2011-05-01

Full Text Available We compiled and analyzed long-term (1961–2005 zooplankton community data in response to environmental variations in Lake Biwa. Environmental data indicate that Lake Biwa had experienced eutrophication (according to the total phosphorus concentration in the late 1960s and recovered to a normal trophic status around 1985, and then has exhibited warming since 1990. Total zooplankton abundance showed a significant correlation with total phytoplankton biomass. Following a classic pattern, the cladoceran/calanoid and cyclopoid/calanoid abundance ratio was related positively to eutrophication. The zooplankton community exhibited a significant response to the boom and bust of phytoplankton biomass as a consequence of eutrophication-reoligotriphication and warming. Moreover, our analyses suggest that the Lake Biwa ecosystem exhibited a hierarchical response across trophic levels; that is, higher trophic levels may show a more delayed response or no response to eutrophication than lower ones.

We tested the hypothesis that the phytoplankton community can better explain the variation of the zooplankton community than bulk environmental variables, considering that the phytoplankton community may directly affect the zooplankton succession through predator-prey interactions. Using a variance partition approach, however, we did not find strong evidence to support this hypothesis. We further aggregated zooplankton according to their feeding types (herbivorous, carnivorous, omnivorous, and parasitic and taxonomic groups, and analyzed the aggregated data. While the pattern remains similar, the results are less clear comparing the results based on finely resolved data. Our research suggests that zooplankton can be bio-indicators of environmental changes; however, the efficacy depends on data resolution.

Marine Litter, Eutrophication and Noise Assessment Tools

Science.gov (United States)

Palazov, Atanas; Velcheva, Maya; Milkova, Tanya; Slabakova, Violeta; Marinova, Veselka

2017-04-01

MARLEN - Marine Litter, Eutrophication and Noise Assessment Tools is a project under the Programme BG02.03: Increased capacity for assessing and predicting environmental status in marine and inland waters, managed by Bulgarian Ministry of environment and waters and co-financed by the Financial Mechanism of the European Economic Area (EEA FM) 2009 - 2014. Project Beneficiary is the Institute of oceanology - Bulgarian Academy of Sciences with two partners: Burgas municipality and Bulgarian Black Sea Basin Directorate. Initial assessment of ecological state of Bulgarian marine waters showed lack of data for some descriptors of MSFD. The main goal of MARLEN is to build up tools for assessment of marine environment by implementing new technologies and best practices for addressing three main areas of interest with lack of marine data in particular: a) Marine litter detection and classification in coastal areas; b) Regular near real time surface water eutrophication monitoring on large aquatory; c) Underwater noise monitoring. Developed tools are an important source of real time, near real time and delay mode marine data for Bulgarian Black Sea waters. The partnership within the project increased capacity for environmental assessments and training of personnel and enhances collaboration between scientific institutes, regional and local authorities. Project results supported implementation of MSFD in Bulgarian marine waters for the benefit of coastal population, marine industry, tourism, marine research and marine spatial planning.

[Effects of light on submerged macrophytes in eutrophic water: research progress].

Science.gov (United States)

Li-Sha, Zou; Ze-Yu, Nie; Xiao-Yan, Yao; Ji-Yan, Shi

2013-07-01

The restoration of submerged macrophytes is the key to remediate eutrophic water and maintain the health of aquatic ecosystem, while light is the main limiting factor. This paper summarized the factors affecting the light extinction in water and the mechanisms of light intensity affecting the physiology of submerged macrophytes, with the focuses on the metabolic mechanisms of carbon, nitrogen, and phosphorus, the responses of antioxidant enzyme system, and the feedbacks of pigment composition and concentration in the common submerged macrophytes under low light stress. Several engineering techniques applied in the ecological restoration of submerged macrophytes were presented, and the framework of the restoration of submerged macrophytes in eutrophic water was proposed. Some problems in current research and several suggestions on future research were addressed, which could help the related research and engineering practices.

African American church-based HIV testing and linkage to care: assets, challenges and needs.

Science.gov (United States)

Stewart, Jennifer M; Thompson, Keitra; Rogers, Christopher

2016-01-01

The US National HIV AIDS strategy promotes the use of faith communities to lessen the burden of HIV in African American communities. One specific strategy presented is the use of these non-traditional venues for HIV testing and co-location of services. African American churches can be at the forefront of this endeavour through the provision of HIV testing and linkage to care. However, there are few interventions to promote the churches' involvement in both HIV testing and linkage to care. We conducted 4 focus groups (n = 39 participants), 4 interviews and 116 surveys in a mixed-methods study to examine the feasibility of a church-based HIV testing and linkage to care intervention in Philadelphia, PA, USA. Our objectives were to examine: (1) available assets, (2) challenges and barriers and (3) needs associated with church-based HIV testing and linkage to care. Analyses revealed several factors of importance, including the role of the church as an access point for testing in low-income neighbourhoods, challenges in openly discussing the relationship between sexuality and HIV, and buy-in among church leadership. These findings can support intervention development and necessitate situating African American church-based HIV testing and linkage to care interventions within a multi-level framework.

Eutrophication management in surface waters using lanthanum modified bentonite

DEFF Research Database (Denmark)

Copetti, Diego; Finsterle, Karin; Marziali, Laura

2016-01-01

This paper reviews the scientific knowledge on the use of a lanthanum modified bentonite (LMB) to manage eutrophication in surface water. The LMB has been applied in around 200 environments worldwide and it has undergone extensive testing at laboratory, mesocosm, and whole lake scales. The availa......This paper reviews the scientific knowledge on the use of a lanthanum modified bentonite (LMB) to manage eutrophication in surface water. The LMB has been applied in around 200 environments worldwide and it has undergone extensive testing at laboratory, mesocosm, and whole lake scales....... The available data underline a high efficiency for phosphorus binding. This efficiency can be limited by the presence of humic substances and competing oxyanions. Lanthanum concentrations detected during a LMB application are generally below acute toxicological threshold of different organisms, except in low...... alkalinity waters. To date there are no indications for long-term negative effects on LMB treated ecosystems, but issues related to La accumulation, increase of suspended solids and drastic resources depletion still need to be explored, in particular for sediment dwelling organisms. Application of LMB...

Interacting effects of sulphate pollution, sulphide toxicity and eutrophication on vegetation development in fens: A mesocosm experiment

International Nuclear Information System (INIS)

Geurts, Jeroen J.M.; Sarneel, Judith M.; Willers, Bart J.C.; Roelofs, Jan G.M.; Verhoeven, Jos T.A.; Lamers, Leon P.M.

2009-01-01

Both eutrophication and SO 4 pollution can lead to higher availability of nutrients and potentially toxic compounds in wetlands. To unravel the interaction between the level of eutrophication and toxicity at species and community level, effects of SO 4 were tested in nutrient-poor and nutrient-rich fen mesocosms. Biomass production of aquatic and semi-aquatic macrophytes and colonization of the water layer increased after fertilization, leading to dominance of highly competitive species. SO 4 addition increased alkalinity and sulphide concentrations, leading to decomposition and additional eutrophication. SO 4 pollution and concomitant sulphide production considerably reduced biomass production and colonization, but macrophytes were less vulnerable in fertilized conditions. The experiment shows that competition between species, vegetation succession and terrestrialization are not only influenced by nutrient availability, but also by toxicity, which strongly interacts with the level of eutrophication. This implies that previously neutralized toxicity effects in eutrophied fens may appear after nutrient reduction measures have been taken. - Interspecific competition, vegetation succession and terrestrialization in fens depend on the interacting effects of SO 4 pollution, sulphide toxicity and nutrient availability.

Effect of coastal eutrophication on growth and physiology of Spartina alterniflora Loisel

Science.gov (United States)

Zhang, Yu; Cui, Baoshan; Xie, Tian; Wang, Qing; Yan, Jiaguo

2018-02-01

Coastal eutrophication has become a driver of coastal wetlands loss. Eutrophication caused by the increase of nitrogen content was one of the most main reasons. We analyzed that exogenous ammonium nitrogen (EAN) of different concentration influenced on the growth and physiology of Spartina alterniflora Loisel (S. alterniflora) through simulated conditions. The results showed that growth of the root system largely depended on the environment conditions around S. alterniflora. Higher nitrogen concentration promoted aboveground biomass and increased plant height. On the other hand, as the increase of growth period, higher nitrogen concentration could inhibit the elongation growth of root and reduce the underground biomass. We showed that activity of POD, SOD and MDA content changed in an upward trend along with the increased nitrogen level. There was a significant positive correlation between H+ flux and NO3- flux (r = 0.601, P < 0.01), and a significant negative correlation between H+ flux and NH4+ flux (r = -0.713, P < 0.01) within 1.5 mm from the root tip of S. alterniflora. Efflux and influx of ions were associated with changes of nitrogen levels. This research will provide data supporting for coastal wetland restoration of biodiversity reduction caused by coastal eutrophication.

Spatial differentiated effect assessment for aquatic eutrophication in Life Cycle Assessment.

NARCIS (Netherlands)

Penailillo, Reinaldo

2005-01-01

The conventional evaluation of aquatic eutrophication in Life Cycle Assessment (LCA) expresses the contribution of nitrogen and/or phosphorus emissions to biomass production in terms of the equivalent emission of a reference substance. This assessment doe

Prospects for Environmental Communication Based on 25 Years of Newspaper Coverage of Climate Change and Eutrophication in Finland

Science.gov (United States)

Lyytimäki, Jari

2015-01-01

Research on long-term media coverage of environmental issues has focused predominantly on English-speaking industrialized countries and on single isolated topics. This article presents a comparative analysis of the Finnish newspaper coverage of climate change and eutrophication from 1990-2014. The coverage of eutrophication showed an annual cycle…

How well do ecosystem indicators communicate the effects of anthropogenic eutrophication?

NARCIS (Netherlands)

McQuatters-Gollop, A.; Gilbert, A.J.; Mee, L.; Vermaat, J.E.; Artioli, Y.; Humborg, C.; Wulff, F.

2009-01-01

Anthropogenic eutrophication affects the Mediterranean, Black, North and Baltic Seas to various extents. Responses to nutrient loading and methods of monitoring relevant indicators vary regionally, hindering interpretation of ecosystem state changes and preventing a straightforward pan-European

Zooplankton responses to sandbar opening in a tropical eutrophic coastal lagoon

Science.gov (United States)

Santangelo, Jayme M.; de M. Rocha, Adriana; Bozelli, Reinaldo L.; Carneiro, Luciana S.; de A. Esteves, Francisco

2007-02-01

The effects of a disturbance by sandbar opening on the zooplankton community were evaluated through a long-term study in an eutrophic and oligohaline system, Imboassica Lagoon, Rio de Janeiro, Brazil. Zooplankton samples and limnological data were collected monthly from March 2000 to February 2003. Before the sandbar was opened in February 2001, the lagoon showed eutrophic conditions, with high mean nutrient concentrations and low salinity (total nitrogen - TN = 190.28 μM, chlorophyll a content - Chl. a = 104.60 μg/L and salinity = 0.87'). During this period, the zooplankton species present, such as the rotifers Brachionus calyciflorus and Brachionus havanaensis, were typical of freshwater to oligohaline and eutrophic environments. After the sandbar opening, the lagoon changed to a lower trophic status and increased salinity (TN = 55.11 μM, Chl. a = 27.56 μg/L and salinity = 19.64'). As a result, the zooplankton community came to consist largely of the rotifer Brachionus plicatilis, marine copepods and meroplanktonic larvae, mainly Gastropoda. Salinity was the main force structuring the zooplankton community after the sandbar opening. Two years after this episode, the prior zooplankton community had not reestablished itself, indicating a low resilience to this disturbance. The conditions developed prior to a sandbar opening can be crucial to the community responses in the face of this disturbance and for the capacity of the original zooplankton community to re-establish itself.

Is nutrient contamination of groundwater causing eutrophication of groundwater-fed meadows?

NARCIS (Netherlands)

Pieterse, N.M.; Olde Venterink, H.; Schot, P.P.; Verkroost, A.W.M.

2005-01-01

There is an ongoing debate as to whether nutrient contamination of groundwater under agricultural fields may cause nutrient-enrichment and subsequent eutrophication in discharge areas. Often, there is only circumstantial evidence to support this supposition (proximity of agricultural fields,

Long-term trends in eutrophication and nutrients in the coastal zone

DEFF Research Database (Denmark)

Clarke, Anne-Marie; Weckström, Kaarina; Conley, Daniel

2006-01-01

We used high-resolution paleoecological records of environmental change to study the rate and magnitude of eutrophication over the last century in two contrasting coastal ecosystems. A multiproxy approach using geochemical and biological indicators and diatom-based transfer functions provides...

The evolution of the eutrophication of the Palić Lake (Serbia ...

African Journals Online (AJOL)

Due to inadequate water quality, it was dried out in 1971 and re-established ... for treated municipal waste waters coming from the lagoons for active sludge ... eutrophication is the enormous amount of sediment at the bottom of the Palic Lake.

Interacting effects of sulphate pollution, sulphide toxicity and eutrophication on vegetation development in fens: A mesocosm experiment

Energy Technology Data Exchange (ETDEWEB)

Geurts, Jeroen J.M., E-mail: j.geurts@b-ware.e [Aquatic Ecology and Environmental Biology, Institute for Wetland and Water Research, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen (Netherlands); B-WARE Research Centre, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen (Netherlands); Sarneel, Judith M. [Landscape Ecology, Institute of Environmental Biology, Utrecht University, Sorbonnelaan 16, 3584 CA Utrecht (Netherlands); Willers, Bart J.C.; Roelofs, Jan G.M. [Aquatic Ecology and Environmental Biology, Institute for Wetland and Water Research, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen (Netherlands); Verhoeven, Jos T.A. [Landscape Ecology, Institute of Environmental Biology, Utrecht University, Sorbonnelaan 16, 3584 CA Utrecht (Netherlands); Lamers, Leon P.M. [Aquatic Ecology and Environmental Biology, Institute for Wetland and Water Research, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen (Netherlands)

2009-07-15

Both eutrophication and SO{sub 4} pollution can lead to higher availability of nutrients and potentially toxic compounds in wetlands. To unravel the interaction between the level of eutrophication and toxicity at species and community level, effects of SO{sub 4} were tested in nutrient-poor and nutrient-rich fen mesocosms. Biomass production of aquatic and semi-aquatic macrophytes and colonization of the water layer increased after fertilization, leading to dominance of highly competitive species. SO{sub 4} addition increased alkalinity and sulphide concentrations, leading to decomposition and additional eutrophication. SO{sub 4} pollution and concomitant sulphide production considerably reduced biomass production and colonization, but macrophytes were less vulnerable in fertilized conditions. The experiment shows that competition between species, vegetation succession and terrestrialization are not only influenced by nutrient availability, but also by toxicity, which strongly interacts with the level of eutrophication. This implies that previously neutralized toxicity effects in eutrophied fens may appear after nutrient reduction measures have been taken. - Interspecific competition, vegetation succession and terrestrialization in fens depend on the interacting effects of SO{sub 4} pollution, sulphide toxicity and nutrient availability.

[MapDraw: a microsoft excel macro for drawing genetic linkage maps based on given genetic linkage data].

Science.gov (United States)

Liu, Ren-Hu; Meng, Jin-Ling

2003-05-01

MAPMAKER is one of the most widely used computer software package for constructing genetic linkage maps.However, the PC version, MAPMAKER 3.0 for PC, could not draw the genetic linkage maps that its Macintosh version, MAPMAKER 3.0 for Macintosh,was able to do. Especially in recent years, Macintosh computer is much less popular than PC. Most of the geneticists use PC to analyze their genetic linkage data. So a new computer software to draw the same genetic linkage maps on PC as the MAPMAKER for Macintosh to do on Macintosh has been crying for. Microsoft Excel,one component of Microsoft Office package, is one of the most popular software in laboratory data processing. Microsoft Visual Basic for Applications (VBA) is one of the most powerful functions of Microsoft Excel. Using this program language, we can take creative control of Excel, including genetic linkage map construction, automatic data processing and more. In this paper, a Microsoft Excel macro called MapDraw is constructed to draw genetic linkage maps on PC computer based on given genetic linkage data. Use this software,you can freely construct beautiful genetic linkage map in Excel and freely edit and copy it to Word or other application. This software is just an Excel format file. You can freely copy it from ftp://211.69.140.177 or ftp://brassica.hzau.edu.cn and the source code can be found in Excel's Visual Basic Editor.

Temperature and cyanobacterial bloom biomass influence phosphorous cycling in eutrophic lake sediments.

Directory of Open Access Journals (Sweden)

Mo Chen

Full Text Available Cyanobacterial blooms frequently occur in freshwater lakes, subsequently, substantial amounts of decaying cyanobacterial bloom biomass (CBB settles onto the lake sediments where anaerobic mineralization reactions prevail. Coupled Fe/S cycling processes can influence the mobilization of phosphorus (P in sediments, with high releases often resulting in eutrophication. To better understand eutrophication in Lake Taihu (PRC, we investigated the effects of CBB and temperature on phosphorus cycling in lake sediments. Results indicated that added CBB not only enhanced sedimentary iron reduction, but also resulted in a change from net sulfur oxidation to sulfate reduction, which jointly resulted in a spike of soluble Fe(II and the formation of FeS/FeS2. Phosphate release was also enhanced with CBB amendment along with increases in reduced sulfur. Further release of phosphate was associated with increases in incubation temperature. In addition, CBB amendment resulted in a shift in P from the Fe-adsorbed P and the relatively unreactive Residual-P pools to the more reactive Al-adsorbed P, Ca-bound P and organic-P pools. Phosphorus cycling rates increased on addition of CBB and were higher at elevated temperatures, resulting in increased phosphorus release from sediments. These findings suggest that settling of CBB into sediments will likely increase the extent of eutrophication in aquatic environments and these processes will be magnified at higher temperatures.

From Enclave to Linkage Economies?

DEFF Research Database (Denmark)

Hansen, Michael W.

as the enclave economy par excellence, moving in with fully integrated value chains, extracting resources and exporting them as commodities having virtually no linkages to the local economy. However, new opportunities for promoting linkages are offered by changing business strategies of local African enterprises...... as well as foreign multinational corporations (MNCs). MNCs in extractives are increasingly seeking local linkages as part of their efficiency, risk, and asset-seeking strategies, and linkage programmes are becoming integral elements in many MNCs’ corporate social responsibility (CSR) activities....... At the same time, local African enterprises are eager to, and increasingly capable of, linking up to the foreign investors in order to expand their activities and acquire technology, skills and market access. The changing strategies of MNCs and the improving capabilities of African enterprises offer new...

Secondary production of the fiddler crab Uca rapax from mangrove areas under anthropogenic eutrophication in the Western Atlantic, Brazil.

Science.gov (United States)

Costa, Tarso de M M; Soares-Gomes, Abilio

2015-12-30

Fiddler crabs Uca rapax were analyzed in three mangrove areas located in both a lagoon and estuarine system in order to study the influence of eutrophication on their population dynamics and production. Populations at the three sites showed a biased sex ratio. Densities were similar at the three sites, but biomass was higher at the lagoon system. Despite biomass being higher at the most eutrophic site, this site exhibited the lowest production. Regarding age structure, the population inhabiting the less eutrophic site mainly comprised younger crabs. The lower production and smaller P/B ratio found in the more eutrophic site were most likely consequences of a high mortality rate and an aged population. Our study evidences the high plasticity of the fiddler crab U. rapax, and confirms secondary production and P/B ratio estimates as useful tools to assess the effects of environmental change. Copyright © 2015 Elsevier Ltd. All rights reserved.

Challenges in administrative data linkage for research

Directory of Open Access Journals (Sweden)

Katie Harron

2017-12-01

Full Text Available Linkage of population-based administrative data is a valuable tool for combining detailed individual-level information from different sources for research. While not a substitute for classical studies based on primary data collection, analyses of linked administrative data can answer questions that require large sample sizes or detailed data on hard-to-reach populations, and generate evidence with a high level of external validity and applicability for policy making. There are unique challenges in the appropriate research use of linked administrative data, for example with respect to bias from linkage errors where records cannot be linked or are linked together incorrectly. For confidentiality and other reasons, the separation of data linkage processes and analysis of linked data is generally regarded as best practice. However, the ‘black box’ of data linkage can make it difficult for researchers to judge the reliability of the resulting linked data for their required purposes. This article aims to provide an overview of challenges in linking administrative data for research. We aim to increase understanding of the implications of (i the data linkage environment and privacy preservation; (ii the linkage process itself (including data preparation, and deterministic and probabilistic linkage methods and (iii linkage quality and potential bias in linked data. We draw on examples from a number of countries to illustrate a range of approaches for data linkage in different contexts.

Identifying causal linkages between environmental variables and African conflicts

Science.gov (United States)

Nguy-Robertson, A. L.; Dartevelle, S.

2017-12-01

Environmental variables that contribute to droughts, flooding, and other natural hazards are often identified as factors contributing to conflict; however, few studies attempt to quantify these causal linkages. Recent research has demonstrated that the environment operates within a dynamical system framework and the influence of variables can be identified from convergent cross mapping (CCM) between shadow manifolds. We propose to use CCM to identify causal linkages between environmental variables and incidences of conflict. This study utilizes time series data from Climate Forecast System ver. 2 and MODIS satellite sensors processed using Google Earth Engine to aggregate country and regional trends. These variables are then compared to Armed Conflict Location & Event Data Project observations at similar scales. Results provide relative rankings of variables and their linkage to conflict. Being able to identify which factors contributed more strongly to a conflict can allow policy makers to prepare solutions to mitigate future crises. Knowledge of the primary environmental factors can lead to the identification of other variables to examine in the causal network influencing conflict.

[Nitrogen and phosphate pollution characteristics and eutrophication evaluation for typical urban landscape waters in Hefei City].

Science.gov (United States)

Li, Ru-Zhong; Liu, Ke-Feng; Qian, Jing; Yang, Ji-Wei; Zhang, Pian-Pian

2014-05-01

To understand the water environment regimes of the city-circling water system in Hefei City, six typical landscape waters were chosen to investigate pollution characteristics of nitrogen and phosphate and evaluate water eutrophication level according to the monitoring data of water physicochemical characteristics and chlorophyll content from September 2012 to July 2013. Study results showed that (1) the six waters mentioned above have been seriously polluted by nitrogen and phosphorus loadings, with the monthly mean values of total nitrogen (TN) and total phosphorus (TP) concentrations far exceeding the universally accepted threshold values of water eutrophication; (2) the nitrogen contents in the waters of Nanfeihe River, Heichiba and Yuhuatang scenic spots exhibited a markedly monthly variation, and both TP and PO(3-)(4)-P in Nanfeihe River showed a fluctuated characteristic with high concentrations while presenting a significant upward trend in Yuhuatang scenic spot; (3) the average values of TN/TP ratios for Yuhuatang and Heichiba scenic spots were 104.7 and 158.3, respectively, and the ratios for Baohe Park, Yinhe Park, Xiaoyaojin Park, and city segment of Nanfeihe River were 16.8, 18.7, 6.4 and 16.8, respectively, indicating that the scenic waters of Yuhuatang and Heichiba were phosphate-limited whereas Xiaoyaojin Park was nitrogen-limited; (4) all the six scenic waters were, in general, subsumed under just two broad categories, namely Hechiba scenic spot and Nanfeihe River, which were seriously polluted, and clustered together, and the others fall into the second class; and (5) water eutrophication appraisal result indicated that the six waters were all in the state of eutrophication, and could be arranged in the order of eutrophication level, Yinhe Park > Heichiba scenic spot > city segment of Nanfeihe River > Xiaoyaojin Park > Yuhuatang scenic spot > Baohe Park.

Herbivory and eutrophication mediate grassland plant nutrient responses across a global climatic gradient

Science.gov (United States)

Anderson, T. Michael; Griffith, Daniel M.; Grace, James B.; Lind, Eric M.; Adler, Peter B.; Biederman, Lori A.; Blumenthal, Dana M.; Daleo, Pedro; Firn, Jennifer; Hagenah, Nicole; Harpole, W. Stanley; MacDougall, Andrew S.; McCulley, Rebecca L.; Prober, Suzanne M.; Risch, Anita C.; Sankaran, Mahesh; Schütz, Martin; Seabloom, Eric W.; Stevens, Carly J.; Sullivan, Lauren; Wragg, Peter; Borer, Elizabeth T.

2018-01-01

Plant stoichiometry, the relative concentration of elements, is a key regulator of ecosystem functioning and is also being altered by human activities. In this paper we sought to understand the global drivers of plant stoichiometry and compare the relative contribution of climatic vs. anthropogenic effects. We addressed this goal by measuring plant elemental (C, N, P and K) responses to eutrophication and vertebrate herbivore exclusion at eighteen sites on six continents. Across sites, climate and atmospheric N deposition emerged as strong predictors of plot‐level tissue nutrients, mediated by biomass and plant chemistry. Within sites, fertilization increased total plant nutrient pools, but results were contingent on soil fertility and the proportion of grass biomass relative to other functional types. Total plant nutrient pools diverged strongly in response to herbivore exclusion when fertilized; responses were largest in ungrazed plots at low rainfall, whereas herbivore grazing dampened the plant community nutrient responses to fertilization. Our study highlights (1) the importance of climate in determining plant nutrient concentrations mediated through effects on plant biomass, (2) that eutrophication affects grassland nutrient pools via both soil and atmospheric pathways and (3) that interactions among soils, herbivores and eutrophication drive plant nutrient responses at small scales, especially at water‐limited sites.

Effects of Simulated Eutrophication and Overfishing on Coral Reef Invertebrates, Algae and Microbes in the Red Sea

OpenAIRE

Jessen, Christian

2013-01-01

Besides the main climate change consequences, ocean warming and acidification, local disturbances such as overfishing and eutrophication are major threats to coral reefs worldwide. Despite its relatively healthy coral reefs that are increasingly faced with growing coastal development, the Red Sea is highly under-investigated, particularly outside the Gulf of Aqaba. This thesis therefore aims to contribute to the understanding of eutrophication and overfishing effects on Red Sea coral reefs by...

Dissolved organic carbon and its potential predictors in eutrophic lakes.

Science.gov (United States)

Toming, Kaire; Kutser, Tiit; Tuvikene, Lea; Viik, Malle; Nõges, Tiina

2016-10-01

Understanding of the true role of lakes in the global carbon cycle requires reliable estimates of dissolved organic carbon (DOC) and there is a strong need to develop remote sensing methods for mapping lake carbon content at larger regional and global scales. Part of DOC is optically inactive. Therefore, lake DOC content cannot be mapped directly. The objectives of the current study were to estimate the relationships of DOC and other water and environmental variables in order to find the best proxy for remote sensing mapping of lake DOC. The Boosted Regression Trees approach was used to clarify in which relative proportions different water and environmental variables determine DOC. In a studied large and shallow eutrophic lake the concentrations of DOC and coloured dissolved organic matter (CDOM) were rather high while the seasonal and interannual variability of DOC concentrations was small. The relationships between DOC and other water and environmental variables varied seasonally and interannually and it was challenging to find proxies for describing seasonal cycle of DOC. Chlorophyll a (Chl a), total suspended matter and Secchi depth were correlated with DOC and therefore are possible proxies for remote sensing of seasonal changes of DOC in ice free period, while for long term interannual changes transparency-related variables are relevant as DOC proxies. CDOM did not appear to be a good predictor of the seasonality of DOC concentration in Lake Võrtsjärv since the CDOM-DOC coupling varied seasonally. However, combining the data from Võrtsjärv with the published data from six other eutrophic lakes in the world showed that CDOM was the most powerful predictor of DOC and can be used in remote sensing of DOC concentrations in eutrophic lakes. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Dynamics of Linkages and Innovativeness in Publicly and ...

African Journals Online (AJOL)

The study examined how linkages among actors in the cocoa and pineapple value chains relate to the innovativeness of actors in the chains. The study showed that a policy environment that promoted public sector leadership in value chain functions and service provision, tended to offer less incentives for smallholder ...

Nitrous oxide emissions could reduce the blue carbon value of marshes on eutrophic estuaries

Science.gov (United States)

Roughan, Brittney L.; Kellman, Lisa; Smith, Erin; Chmura, Gail L.

2018-04-01

The supply of nitrogen to ecosystems has surpassed the Earth’s Planetary Boundary and its input to the marine environment has caused estuarine waters to become eutrophic. Excessive supply of nitrogen to salt marshes has been associated with shifts in species’ distribution and production, as well as marsh degradation and loss. Our study of salt marshes in agriculturally intensive watersheds shows that coastal eutrophication can have an additional impact. We measured gas fluxes from marsh soils and verified emissions of nitrous oxide (N2O) in nitrogen-loaded marshes while the reference marsh was a sink for this gas. Salt marsh soils are extremely efficient carbon sinks, but emissions of N2O, a greenhouse gas 298 times more potent than CO2, reduces the value of the carbon sink, and in some marshes, may counterbalance any value of stored carbon towards mitigation of climate change. Although more research is merited on the nitrogen transformations and carbon storage in eutrophic marshes, the possibility of significant N2O emissions should be considered when evaluating the market value of carbon in salt marshes subject to high levels of nitrogen loading.

Are bacteria an important food source for rotifers in eutrophic lakes?

NARCIS (Netherlands)

Ooms-Wilms, A.L.

1997-01-01

In situ grazing measurements using fluorescent particles of 0.5, 2.4 and 6.3 mu m diameter in eutrophic Lake Loosdrecht (The Netherlands) showed that Anuraeopsis fissa, a small rotifer, filtered the smallest, bacteria sized particles as efficiently or more efficiently than the larger particles. In

Spatial and temporal variation of phytoplankton in a tropical eutrophic river.

Science.gov (United States)

Santana, L M; Moraes, M E B; Silva, D M L; Ferragut, C

2016-04-19

This study aims to evaluate the environmental factors determining of the changes in phytoplankton structure in spatial (upper, middle and lower course) and seasonal (dry and rainy period) scales in a eutrophic river (Almada River, northeastern Brazil). In the study period, total accumulated rainfall was below of the historic average, resulting in flow reduction, mainly in rainy period. High orthophosphate concentration was found at the sampling sites. Phytoplankton chlorophyll a increased from upstream to downstream. Geitlerinema splendidum (S1) and Chlamydomonas sp. (X2) were the most abundant species in the upper course and several species of diatoms (D), Euglenophyceae (W1, W2) and Chlorophyceae (X1) in the middle and lower course. The functional groups were found to be characteristic of lotic ecosystem, shallow, with low light availability, rich in organic matter and eutrophic environments. We conclude that phytoplankton community structure was sensitive to change of the river flow and nutrient availability in spatial and seasonal scale in a tropical river.

Spatial and temporal variation of phytoplankton in a tropical eutrophic river

Directory of Open Access Journals (Sweden)

L. M. Santana

Full Text Available Abstract This study aims to evaluate the environmental factors determining of the changes in phytoplankton structure in spatial (upper, middle and lower course and seasonal (dry and rainy period scales in a eutrophic river (Almada River, northeastern Brazil. In the study period, total accumulated rainfall was below of the historic average, resulting in flow reduction, mainly in rainy period. High orthophosphate concentration was found at the sampling sites. Phytoplankton chlorophyll a increased from upstream to downstream. Geitlerinema splendidum (S1 and Chlamydomonas sp. (X2 were the most abundant species in the upper course and several species of diatoms (D, Euglenophyceae (W1, W2 and Chlorophyceae (X1 in the middle and lower course. The functional groups were found to be characteristic of lotic ecosystem, shallow, with low light availability, rich in organic matter and eutrophic environments. We conclude that phytoplankton community structure was sensitive to change of the river flow and nutrient availability in spatial and seasonal scale in a tropical river.

Editorial - A critical perspective on geo-engineering for eutrophication management in lakes

DEFF Research Database (Denmark)

Lürling, Miquel; Mackay, Eleanor; Reitzel, Kasper

2016-01-01

Eutrophication is the primary worldwide water quality issue. Reducing excessive external nutrient loading is the most straightforward action in mitigating eutrophication, but lakes, ponds and reservoirs often show little, if any, signs of recovery in the years following external load reduction...... accumulation in surface waters, thereby speeding up recovery. In this overview, we draw on evidence from this special issue Geoengineering in Lakes, and on supporting literature to provide a critical perspective on the approach. We demonstrate that many of the strong P sorbents in the literature...... will not be applicable in the field because of costs and other constraints. Aluminium and lanthanum modified compounds are among the most effective compounds for targeting P. Flocculants and ballast compounds can be used to sink cyanobacteria, in the short term. We emphasize that the first step in managing...

Synthesis and properties of ApA analogues with shortened phosphonate internucleotide linkage.

Science.gov (United States)

Králíková, Sárka; Buděšínský, Miloš; Barvík, Ivan; Masojídková, Milena; Točík, Zdeněk; Rosenberg, Ivan

2011-01-01

A complete series of the 2 '-5 ' and 3 '-5 ' regioisomeric types of r(ApA) and 2 '-d(ApA) analogues with the α-hydroxy-phosphonate C3 '-O-P-CH(OH)-C4 ″ internucleotide linkage, isopolar but non-isosteric with the phosphodiester one, were synthesized and their hybridization properties with polyU studied. Due to the chirality on the 5 '-carbon atom of the modified internucleotide linkage bearing phosphorus and hydroxy moieties, each regioisomeric type of ApA dimer is split into epimeric pairs. To examine the role of the 5 '-hydroxyl of the α-hydroxy-phosphonate moiety during hybridization, the appropriate r(ApA) analogues with 3 '(2 ')-O-P-CH(2)-C4 ″ linkage lacking the 5 '-hydroxyl were synthesized. Nuclear magnetic resonance (NMR) spectroscopy study on the conformation of the modified sugar-phosphate backbone, along with the hybridization measurements, revealed remarkable differences in the stability of complexes with polyU, depending on the 5 '-carbon atom configuration. Potential usefulness of the α-hydroxy-phosphonate linkage in modified oligoribonucleotides is discussed.

Response of invertebrates from the hyporheic zone of chalk rivers to eutrophication and land use.

Science.gov (United States)

Pacioglu, Octavian; Moldovan, Oana Teodora

2016-03-01

Whereas the response of lotic benthic macroinvertebrates to different environmental stressors is a widespread practice nowadays in assessing the water and habitat quality, the use of hyporheic zone invertebrates is still in its infancy. In this study, classification and regression trees analysis were employed in order to assess the ecological requirements and the potential as bioindicators for the hyporheic zone invertebrates inhabiting four lowland chalk rivers (south England) with contrasting eutrophication levels (based on surface nitrate concentrations) and magnitude of land use (based on percentage of fine sediments load and median interstitial space). Samples of fauna, water and sediment were sampled twice, during low (summer) and high (winter) groundwater level, at depths of 20 and 35 cm. Certain groups of invertebrates (Glossosomatidae and Psychomyiidae caddisflies, and riffle beetles) proved to be good indicators of rural catchments, moderately eutrophic and with high fine sediment load. A diverse community dominated by microcrustaceans (copepods and ostracods) were found as good indicators of highly eutrophic urban streams, with moderate-high fine sediment load. However, the use of other taxonomic groups (e.g. chironomids, oligochaetes, nematodes, water mites and the amphipod Gammarus pulex), very widespread in the hyporheic zone of all sampled rivers, is of limited use because of their high tolerance to the analysed stressors. We recommend the use of certain taxonomic groups (comprising both meiofauna and macroinvertebrates) dwelling in the chalk hyporheic zone as indicators of eutrophication and colmation and, along with routine benthic sampling protocols, for a more comprehensive water and habitat quality assessment of chalk rivers.

Probabilistic linkage to enhance deterministic algorithms and reduce data linkage errors in hospital administrative data.

Science.gov (United States)

Hagger-Johnson, Gareth; Harron, Katie; Goldstein, Harvey; Aldridge, Robert; Gilbert, Ruth

2017-06-30

 BACKGROUND: The pseudonymisation algorithm used to link together episodes of care belonging to the same patients in England (HESID) has never undergone any formal evaluation, to determine the extent of data linkage error. To quantify improvements in linkage accuracy from adding probabilistic linkage to existing deterministic HESID algorithms. Inpatient admissions to NHS hospitals in England (Hospital Episode Statistics, HES) over 17 years (1998 to 2015) for a sample of patients (born 13/28th of months in 1992/1998/2005/2012). We compared the existing deterministic algorithm with one that included an additional probabilistic step, in relation to a reference standard created using enhanced probabilistic matching with additional clinical and demographic information. Missed and false matches were quantified and the impact on estimates of hospital readmission within one year were determined. HESID produced a high missed match rate, improving over time (8.6% in 1998 to 0.4% in 2015). Missed matches were more common for ethnic minorities, those living in areas of high socio-economic deprivation, foreign patients and those with 'no fixed abode'. Estimates of the readmission rate were biased for several patient groups owing to missed matches, which was reduced for nearly all groups. CONCLUSION: Probabilistic linkage of HES reduced missed matches and bias in estimated readmission rates, with clear implications for commissioning, service evaluation and performance monitoring of hospitals. The existing algorithm should be modified to address data linkage error, and a retrospective update of the existing data would address existing linkage errors and their implications.

A Formalization of Linkage Analysis

DEFF Research Database (Denmark)

Ingolfsdottir, Anna; Christensen, A.I.; Hansen, Jens A.

In this report a formalization of genetic linkage analysis is introduced. Linkage analysis is a computationally hard biomathematical method, which purpose is to locate genes on the human genome. It is rooted in the new area of bioinformatics and no formalization of the method has previously been ...

Deterioration of atlantic soft water macrophyte communities by acidification, eutrophication and alkalinisation

NARCIS (Netherlands)

Arts, G.H.P.

2002-01-01

This review presents an overview of the most important succession patterns and underlying processes associated with the deterioration of soft water macrophyte communities in atlantic and boreo-atlantic regions. As acidification, eutrophication and alkalinisation are the dominant processes, this

Patient and provider perspectives on improving the linkage of HIV ...

African Journals Online (AJOL)

This study examined barriers and facilitators to the linkage of HIV-positive pregnant women from antenatal care (ANC) to long-term HIV care from patient and provider perspectives, following the implementation of a collaborative quality improvement project in Eastern Uganda. It also solicited recommendations for improving ...

Sedimentary iron–phosphorus cycling under contrasting redox conditions in a eutrophic estuary

NARCIS (Netherlands)

Kraal, Peter; Burton, Edward D.; Rose, Andrew L.; Kocar, Benjamin D.; Lockhart, Robert S.; Grice, Kliti; Bush, Richard T.; Tan, Eileen; Webb, Samuel M.

2015-01-01

Phosphorus (P) is often a limiting nutrient within freshwater and estuarine systems, thus excess inputs of P from anthropogenic activities (dominantly agriculture) can induce eutrophication in receiving water bodies. The sequestration of P within estuarine sediments is controlled by sorption and

Thermally actuated linkage arrangement

International Nuclear Information System (INIS)

Anderson, P.M.

1981-01-01

A reusable thermally actuated linkage arrangement includes a first link member having a longitudinal bore therein adapted to receive at least a portion of a second link member therein, the first and second members being sized to effect an interference fit preventing relative movement there-between at a temperature below a predetermined temperature. The link members have different coefficients of thermal expansion so that when the linkage is selectively heated by heating element to a temperature above the predetermined temperature, relative longitudinal and/or rotational movement between the first and second link members is enabled. Two embodiments of a thermally activated linkage are disclosed which find particular application in actuators for a grapple head positioning arm in a nuclear reactor fuel handling mechanism to facilitate back-up safety retraction of the grapple head independently from the primary fuel handling mechanism drive system. (author)

Eutrophication patterns in an eastern Mediterranean coastal lagoon: Vassova, Delta Nestos, Macedonia, Greece

Directory of Open Access Journals (Sweden)

S. ORFANIDIS

2005-12-01

Full Text Available The results of an intensive monitoring study of main eutrophication parameters in relation to fish farming management, climate and hydrography in the Vassova coastal lagoon (Nestos Delta are presented. The overall aim is to produce basic knowledge in order to contribute to the management of eutrophication of coastal lagoons at local and national levels. Due to extensive spatiotemporal variability of the measured parameters correlation and regression polynomial analysis was used to identify patterns (p<0.05. Freshwater was the main source of nitrate and phosphate in the lagoon. This finding has justified the reduction of freshwater inflow in the past, which, however, has increased mean salinity to 30 PSU and reduced spatial salinity gradients. Maximum nitrate values in winter coincided with adverse climatic and hydrographic conditions (high precipitation, strong NE to E winds and low tide and fish farming management that hinder water circulation. Dissolved phosphorus variability indicated the combination of the external (freshwaters and internal (sediment P-sources. N/P water values indicated nitrogen being the most important nutrient for primary producers throughout the year, except in winter, when phosphorus was the most important nutrient. Practical measures for improving fish farming practices to decrease “eutrophication risk” during winter are suggested. Existing nutrient data from the Vassova and from other Greek lagoons in comparison were also presented and discussed.

Assessing ways to combat eutrophication in a Chinese drinking water reservoir using SWAT

DEFF Research Database (Denmark)

Nielsen, Anders; Trolle, Dennis; Me, W

2013-01-01

Across China, nutrient losses associated with agricultural production and domestic sewage have triggered eutrophication, and local managers are challenged to comply with drinking water quality requirements. Evidently, the improvement of water quality should be targeted holistically and encompass...... in land and livestock management and sewage treatment on nutrient export and derived consequences for water quality in the Chinese subtropical Kaiping (Dashahe) drinking water reservoir (supplying 0.4 million people). The critical load of TP was estimated to 13.5 tonnes yr–1 in order to comply...... both point sources and surface activities within the watershed of a reservoir. We expanded the ordinary Soil Water Assessment Tool – (SWAT) with a widely used empirical equation to estimate total phosphorus (TP) concentrations in lakes and reservoirs. Subsequently, we examined the effects of changes...

Linkages over Time between Adolescents' Relationships with Parents and Friends

Science.gov (United States)

De Goede, Irene H. A.; Branje, Susan J. T.; Delsing, Marc J. M. H.; Meeus, Wim H. J.

2009-01-01

This 5-wave longitudinal study examines linkages over time between adolescents' perceptions of relationships with parents and friends with respect to support, negative interaction, and power. A total of 575 early adolescents (54.1% boys) and 337 middle adolescents (43.3% boys) participated. Path analyses mainly showed bidirectional associations…

The role of shellfish aquaculture in reduction of eutrophication in an urban estuary

DEFF Research Database (Denmark)

Bricker, Suzanne B.; Ferreira, Joao Gomes; Zhu, Changbo

2018-01-01

from the system-scale modeling, suggesting that this upscaling method could be useful in waterbodies without circulation models. The minimum value of the ecosystem service of nitrogen removed by oyster production was estimated by means of an avoided costs method, which uses the cost of alternative......, as an example of how aquaculture might complement land-based measures in urban estuaries. Eutrophication status, nutrient removal, and ecosystem service value were estimated through eutrophication assessment, application of hydrologic, circulation, and local- and ecosystem-scale models, and economic valuation....... System-scale modeling estimated that current oyster aquaculture, via sequestration into tissue and shell only, removes an equivalent of 1.31%, and expanded production could remove 2.68%, of total annual land-based nitrogen inputs by aquaculture alone. Up-scaled local-scale results were similar to results...

Hidden linkages between urbanization and food systems.

Science.gov (United States)

Seto, Karen C; Ramankutty, Navin

2016-05-20

Global societies are becoming increasingly urban. This shift toward urban living is changing our relationship with food, including how we shop and what we buy, as well as ideas about sanitation and freshness. Achieving food security in an era of rapid urbanization will require considerably more understanding about how urban and food systems are intertwined. Here we discuss some potential understudied linkages that are ripe for further examination. Copyright © 2016, American Association for the Advancement of Science.

The ties that bind: interorganizational linkages and physician-system alignment.

Science.gov (United States)

Alexander, J A; Waters, T M; Burns, L R; Shortell, S M; Gillies, R R; Budetti, P P; Zuckerman, H S

2001-07-01

To examine the association between the degree of alignment between physicians and health care systems, and interorganizational linkages between physician groups and health care systems. The study used a cross sectional, comparative analysis using a sample of 1,279 physicians practicing in loosely affiliated arrangements and 1,781 physicians in 61 groups closely affiliated with 14 vertically integrated health systems. Measures of physician alignment were based on multiitem scales validated in previous studies and derived from surveys sent to individual physicians. Measures of interorganizational linkages were specified at the institutional, administrative, and technical core levels of the physician group and were developed from surveys sent to the administrator of each of the 61 physician groups in the sample. Two stage Heckman models with fixed effects adjustments in the second stage were used to correct for sample selection and clustering respectively. After accounting for sample selection, fixed effects, and group and individual controls, physicians in groups with more valued practice service linkages display consistently higher alignment with systems than physicians in groups that have fewer such linkages. Results also suggest that centralized administrative control lowers physician-system alignment for selected measures of alignment. Governance interlocks exhibited only weak associations with alignment. Our findings suggest that alignment generally follows resource exchanges that promote value-added contributions to physicians and physician groups while preserving control and authority within the group.

Modelling the influence of changing climate in present and future marine eutrophication impacts from spring barley production

DEFF Research Database (Denmark)

Cosme, Nuno Miguel Dias; Niero, Monia

2017-01-01

Nitrate concentration and runoff are site-specific and driven by climatic factors and crop management. As such, nitrate emissions may increase in the future due to climate change, affecting the marine eutrophication mechanism. In this context, and considering the case of spring barley production...... of different normalisation references when comparing future Life Cycle Assessment (LCA) scenarios with current production systems. A parameterised characterisation model was developed to gauge the influence of future climatic-driven pressures on the marine eutrophication impact pathway. Spatial differentiation...

High abundance and diversity of consumers associated with eutrophic areas in a semi-desert macrotidal coastal ecosystem in Patagonia, Argentina

Science.gov (United States)

Martinetto, Paulina; Daleo, Pedro; Escapa, Mauricio; Alberti, Juan; Isacch, Juan Pablo; Fanjul, Eugenia; Botto, Florencia; Piriz, Maria Luz; Ponce, Gabriela; Casas, Graciela; Iribarne, Oscar

2010-07-01

Here we evaluated the response to eutrophication in terms of abundance and diversity of flora and fauna in a semi-desert macrotidal coastal system (San Antonio bay, Patagonia, Argentina, 40° 48' S) where signs of eutrophication (high nutrient concentration, seaweed blooms, high growth rate of macroalgae) have been reported. We compared abundances and species composition of macroalgae, small infaunal and epifaunal invertebrates, and birds associated with tidal channels of the San Antonio Bay subject to contrasting anthropogenic influence. Macroalgae were more abundant and diverse in the channel closer to human activity where nutrient concentrations were also higher. In contrast to what others have observed in eutrophic sites, small invertebrates and birds were also more abundant and diverse in the channel with macroalgal blooms and high nutrient concentration. The large water flushing during the tidal cycle could prevent anoxic or hypoxic events, making the environment suitable for consumers. Thus, this could be a case in which eutrophication supports high densities of consumers by increasing food availability, rather than negatively affecting the survival of organisms.

Modeling Diel Oxygen Dynamics and Ecosystem Metabolism in a Shallow, Eutrophic Estuary

Science.gov (United States)

Weeks Bay is a shallow eutrophic estuary that exhibits frequent summertime diel-cycling hypoxia and periods of dissolved oxygen (DO) oversaturation during the day. Diel DO dynamics in shallow estuaries like Weeks Bay are complex, and may be influenced by wind forcing, vertical an...

Changes in fish production effectivity in eutrophic fishponds of zooplankton structure

Czech Academy of Sciences Publication Activity Database

Potužák, J.; Hůda, J.; Pechar, Libor

2007-01-01

Roč. 15, - (2007), s. 201-210 ISSN 0967-6120 R&D Projects: GA MŽP(CZ) SM/640/18/03; GA MŽP(CZ) SL/1/6/04 Institutional research plan: CEZ:AV0Z60870520 Keywords : fishponds * zooplankton * eutrophication * fish management * primary production Subject RIV: GL - Fishing Impact factor: 0.828, year: 2007

Geo-engineering experiments in two urban ponds to control eutrophication.

Science.gov (United States)

Waajen, Guido; van Oosterhout, Frank; Douglas, Grant; Lürling, Miquel

2016-06-15

Many urban ponds experience detrimental algal blooms as the result of eutrophication. During a two year field experiment, the efficacy of five in situ treatments to mitigate eutrophication effects in urban ponds was studied. The treatments targeted the sediment phosphorus release and were intended to switch the ponds from a turbid phytoplankton-dominated state to a clear-water state with a low phytoplankton biomass. Two eutrophic urban ponds were each divided into six compartments (300-400 m(2); 210-700 m(3)). In each pond the following treatments were tested: dredging in combination with biomanipulation (involving fish biomass control and the introduction of macrophytes) with and without the addition of the flocculant polyaluminiumchloride, interception and reduction of sediment phosphorus release with lanthanum-modified bentonite (Phoslock(®)) in combination with biomanipulation with and without polyaluminiumchloride; biomanipulation alone; and a control. Trial results support the hypothesis that the combination of biomanipulation and measures targeting the sediment phosphorus release can be effective in reducing the phytoplankton biomass and establishing and maintaining a clear-water state, provided the external phosphorus loading is limited. During the experimental period dredging combined with biomanipulation showed mean chlorophyll-a concentrations of 5.3 and 6.2 μg L(-1), compared to 268.9 and 52.4 μg L(-1) in the control compartments. Lanthanum-modified bentonite can be an effective alternative to dredging and in combination with biomanipulation it showed mean chlorophyll-a concentrations of 5.9 and 7.6 μg L(-1). Biomanipulation alone did not establish a clear-water state or only during a limited period. As the two experimental sites differed in their reaction to the treatments, it is important to choose the most promising treatment depending on site specific characteristics. In recovering the water quality status of urban ponds, continuing

Multiobjective optimization of a steering linkage

Energy Technology Data Exchange (ETDEWEB)

Sleesonsom, S.; Bureerat, S. [Sustainable and Infrastructure Research and Development Center, Dept. of Mechanical Engineering, Faculty of Engineering, Khon Kaen University, Khon Kaen (Thailand)

2016-08-15

In this paper, multi-objective optimization of a rack-and-pinion steering linkage is proposed. This steering linkage is a common mechanism used in small cars with three advantages as it is simple to construct, economical to manufacture, and compact and easy to operate. In the previous works, many researchers tried to minimize a steering error but minimization of a turning radius is somewhat ignored. As a result, a multi-objective optimization problem is assigned to simultaneously minimize a steering error and a turning radius. The design variables are linkage dimensions. The design problem is solved by the hybrid of multi-objective population-based incremental learning and differential evolution with various constraint handling schemes. The new design strategy leads to effective design of rack-and-pinion steering linkages satisfying both steering error and turning radius criteria.

Multiobjective optimization of a steering linkage

International Nuclear Information System (INIS)

Sleesonsom, S.; Bureerat, S.

2016-01-01

In this paper, multi-objective optimization of a rack-and-pinion steering linkage is proposed. This steering linkage is a common mechanism used in small cars with three advantages as it is simple to construct, economical to manufacture, and compact and easy to operate. In the previous works, many researchers tried to minimize a steering error but minimization of a turning radius is somewhat ignored. As a result, a multi-objective optimization problem is assigned to simultaneously minimize a steering error and a turning radius. The design variables are linkage dimensions. The design problem is solved by the hybrid of multi-objective population-based incremental learning and differential evolution with various constraint handling schemes. The new design strategy leads to effective design of rack-and-pinion steering linkages satisfying both steering error and turning radius criteria

Modeling the eutrophication of two mature planted stormwater ponds for runoff control

DEFF Research Database (Denmark)

Wium-Andersen, Tove; Nielsen, A.H.; Hvitved-Jacobsen, Thorkild

2013-01-01

A model, targeting eutrophication of stormwater detention ponds was developed and applied to sim-ulate pH, dissolved oxygen and the development of algae and plant biomass in two mature plantedwetponds for run off control. The model evaluated algal and plant biomass growth into three groupsnamely;...

Accuracy of Probabilistic Linkage Using the Enhanced Matching System for Public Health and Epidemiological Studies.

Science.gov (United States)

Aldridge, Robert W; Shaji, Kunju; Hayward, Andrew C; Abubakar, Ibrahim

2015-01-01

The Enhanced Matching System (EMS) is a probabilistic record linkage program developed by the tuberculosis section at Public Health England to match data for individuals across two datasets. This paper outlines how EMS works and investigates its accuracy for linkage across public health datasets. EMS is a configurable Microsoft SQL Server database program. To examine the accuracy of EMS, two public health databases were matched using National Health Service (NHS) numbers as a gold standard unique identifier. Probabilistic linkage was then performed on the same two datasets without inclusion of NHS number. Sensitivity analyses were carried out to examine the effect of varying matching process parameters. Exact matching using NHS number between two datasets (containing 5931 and 1759 records) identified 1071 matched pairs. EMS probabilistic linkage identified 1068 record pairs. The sensitivity of probabilistic linkage was calculated as 99.5% (95%CI: 98.9, 99.8), specificity 100.0% (95%CI: 99.9, 100.0), positive predictive value 99.8% (95%CI: 99.3, 100.0), and negative predictive value 99.9% (95%CI: 99.8, 100.0). Probabilistic matching was most accurate when including address variables and using the automatically generated threshold for determining links with manual review. With the establishment of national electronic datasets across health and social care, EMS enables previously unanswerable research questions to be tackled with confidence in the accuracy of the linkage process. In scenarios where a small sample is being matched into a very large database (such as national records of hospital attendance) then, compared to results presented in this analysis, the positive predictive value or sensitivity may drop according to the prevalence of matches between databases. Despite this possible limitation, probabilistic linkage has great potential to be used where exact matching using a common identifier is not possible, including in low-income settings, and for vulnerable

Influence of eutrophication on metal bioaccumulation and oral bioavailability in oysters, Crassostrea angulata.

Science.gov (United States)

Li, Shun-Xing; Chen, Li-Hui; Zheng, Feng-Ying; Huang, Xu-Guang

2014-07-23

Oysters (Crassostrea angulata) are often exposed to eutrophication. However, how these exposures influence metal bioaccumulation and oral bioavailability (OBA) in oysters is unknown. After a four month field experimental cultivation, bioaccumulation factors (BAF) of metals (Fe, Cu, As, Cd, and Pb) from seawater to oysters and metal oral bioavailability in oysters by bionic gastrointestinal tract were determined. A positive effect of macronutrient (nitrate N and total P) concentration in seawater on BAF of Cd in oysters was observed, but such an effect was not significant for Fe, Cu, Pb, and As. Only OBA of As was significantly positively correlated to N and P contents. For Fe, OBA was negatively correlated with N. The regular variation of the OBA of Fe and As may be due to the effect of eutrophication on the synthesis of metal granules and heat-stable protein in oysters, respectively.

Reevaluating Musculoskeletal Linkages in Suction-Feeding Fishes with X-Ray Reconstruction of Moving Morphology (XROMM).

Science.gov (United States)

Camp, Ariel L; Brainerd, Elizabeth L

2015-07-01

Suction-feeding fishes encompass a vast diversity of morphologies and ecologies, but during feeding they all rely on musculoskeletal linkages and levers to transform the shortening of muscle into 3D expansion of the mouth cavity. To relate the shape of these skeletal elements to their function in expansion of the mouth, four-bar linkage models have been developed and widely used in studies of ecology, evolution, and development. However, we have lacked the ability to test the predictions of these 2D linkage models against the actual 3D motions of fishes' skulls. A new imaging method, X-ray Reconstruction of Moving Morphology (XROMM), now makes it possible to measure 3D skeletal motions relative to other bones within the head and relative to the fish's body, and thereby to examine directly the proposed linkages. We used XROMM to examine the opercular linkage, in which shortening of the levator operculi muscle is hypothesized to retract the operculum, and thereby the interoperculum and interoperculomandibular ligament to generate depression of the lower jaw about the quadratomandibular joint. XROMM animations of suction strikes in largemouth bass revealed that the operculum is indeed retracted relative to the suspensorium as the levator operculi muscle shortens and the jaw depresses. However, the four-bar model of this linkage overestimates the depression of the jaw by nearly a factor of two. Therefore, caution should be used in interpreting and applying the predictions of this linkage model. When we measured kinematics relative to the fish's body, we found that the operculum was relatively stable, whereas the suspensorium was elevated along with the neurocranium, pushing the quadratomandibular joint forward to produce depression of the jaw. Thus, it is the epaxial muscles elevating the neurocranium that powers depression of the jaw through the opercular linkage. However, the levator operculi muscle plays a crucial role in stabilizing the operculum to allow elevation

Eutrophication potential of Payette Lake, Idaho

Science.gov (United States)

Woods, Paul F.

1997-01-01

Payette Lake was studied during water years 1995-96 to determine the 20.5-square-kilometer lake's assimilative capacity for nutrients and, thus, its eutrophication potential. The study included quantification of hydrologic and nutrient budgets, characterization of water quality in the limnetic and littoral zones, development of an empirical nutrient load/lake response model, and estimation of the limnological effects of a large-scale forest fire in the lake's 373-square-kilometer watershed during the autumn of 1994. Streamflow from the North Fork Payette River, the lake's primary tributary, delivered about 73 percent of the lake's inflow over the 2 years. Outflow from the lake, measured since 1908, was 128 and 148 percent of the long-term average in 1995 and 1996, respectively. The larger volumes of outflow reduced the long-term average water-

Some methods for blindfolded record linkage

Directory of Open Access Journals (Sweden)

Christen Peter

2004-06-01

Full Text Available Abstract Background The linkage of records which refer to the same entity in separate data collections is a common requirement in public health and biomedical research. Traditionally, record linkage techniques have required that all the identifying data in which links are sought be revealed to at least one party, often a third party. This necessarily invades personal privacy and requires complete trust in the intentions of that party and their ability to maintain security and confidentiality. Dusserre, Quantin, Bouzelat and colleagues have demonstrated that it is possible to use secure one-way hash transformations to carry out follow-up epidemiological studies without any party having to reveal identifying information about any of the subjects – a technique which we refer to as "blindfolded record linkage". A limitation of their method is that only exact comparisons of values are possible, although phonetic encoding of names and other strings can be used to allow for some types of typographical variation and data errors. Methods A method is described which permits the calculation of a general similarity measure, the n-gram score, without having to reveal the data being compared, albeit at some cost in computation and data communication. This method can be combined with public key cryptography and automatic estimation of linkage model parameters to create an overall system for blindfolded record linkage. Results The system described offers good protection against misdeeds or security failures by any one party, but remains vulnerable to collusion between or simultaneous compromise of two or more parties involved in the linkage operation. In order to reduce the likelihood of this, the use of last-minute allocation of tasks to substitutable servers is proposed. Proof-of-concept computer programmes written in the Python programming language are provided to illustrate the similarity comparison protocol. Conclusion Although the protocols described in

Floating rice-culture system for nutrient remediation and feed production in a eutrophic lake.

Science.gov (United States)

Srivastava, Ankita; Chun, Seong-Jun; Ko, So-Ra; Kim, Junhwan; Ahn, Chi-Yong; Oh, Hee-Mock

2017-12-01

The increased inputs of nutrients have been demonstrated to be a major contributing factor to the eutrophication of lakes and reservoirs which can lead to the production of harmful algal/cyanobacterial blooms and deleteriously affect the aesthetics of water-bodies. Floating plant-culture systems have been widely used for the ecological remediation of eutrophic water in a cost-effective manner. We investigated the applicability of Korean japonica rice variety 'Nampyeong' in a floating-culture system in a eutrophic lake for nutrient uptake and biomass production. Chemical and organic compound compositions were analyzed two times during the growth stages of the rice plant: 98 DAT (days after transplanting) and 165 DAT. Total nitrogen and phosphorus contributed around 1.36 and 0.15 (% dry weight), respectively, in rice plant components at 165 DAT. Crude protein, lipids, fiber and ash were 4.35, 1.91, 23.66 and 5.55 (% dry weight), respectively. In addition, microcystin levels in the rice plant components ranged from 0.0008 to 0.002 μg/g and did not exceed the recommended tolerable limits. These results suggested that the developed floating rice-culture system showed a good potential as a holistic management approach in terms of nutrient reduction, rice production for further use as feed and for bloom control. Copyright © 2017 Elsevier Ltd. All rights reserved.

Monitoring and predicting eutrophication of Sri Lankan inland waters using ASTER satellite data

Science.gov (United States)

Dahanayaka, D. D. G. L.; Wijeyaratne, M. J. S.; Tonooka, H.; Minato, A.; Ozawa, S.; Perera, B. D. C.

2014-10-01

This study focused on determining the past changes and predicting the future trends in eutrophication of the Bolgoda North lake, Sri Lanka using in situ Chlorophyll-a (Chl-a) measurements and Advanced Spaceborne Thermal Emission and Reflectance Radiometer (ASTER) satellite data. This Lake is located in a mixed land use area with industries, some agricultural lands, middle income and high income housing, tourist hotels and low income housing. From March to October 2013, water samples from five sampling sites were collected once a month parallel to ASTER overpass and Chl-a, nitrate and phosphate contents of each sample were measured using standard laboratory methods. Cloud-free ASTER scenes over the lake during the 2000-2013 periods were acquired for Chl-a estimation and trend analysis. All ASTER images were atmospherically corrected using FLAASH software and in-situ Chl-a data were regressed with atmospherically corrected three ASTER VNIR band ratios of the same date. The regression equation of the band ratio and Chl-a content with the highest correlation, which was the green/red band ratio was used to develop algorithm for generation of 15-m resolution Chl-a distribution maps. According to the ASTER based Chl-a distribution maps it was evident that eutrophication of this lake has gradually increased from 2008-2011. Results also indicated that there had been significantly high eutrophic conditions throughout the year 2013 in several regions, especially in water stagnant areas and adjacent to freshwater outlets. Field observations showed that this lake is receiving various discharges from factories. Unplanned urbanization and inadequacy of proper facilities in the nearby industries for waste management have resulted in the eutrophication of the water body. If the present trends of waste disposal and unplanned urbanization continue, enormous environmental problems would be resulted in future. Results of the present study showed that information from satellite remote

Increase in dimethylsulfide (DMS emissions due to eutrophication of coastal waters offsets their reduction due to ocean acidification.

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Nathalie eGypens

2014-04-01

Full Text Available Available information from manipulative experiments suggested that the emission of dimethylsulfide (DMS would decrease in response to the accumulation of anthropogenic CO2 in the ocean (ocean acidification. However, in coastal environments, the carbonate chemistry of surface waters was also strongly modified by eutrophication and related changes in biological activity (increased primary production and change in phytoplankton dominance during the last 50 years. Here, we tested the hypothesis that DMS emissions in marine coastal environments also strongly responded to eutrophication in addition to ocean acidification at decadal timescales. We used the R-MIRO-BIOGAS model in the eutrophied Southern Bight of the North Sea characterized by intense blooms of Phaeocystis that are high producers of dimethylsulfoniopropionate (DMSP, the precursor of DMS. We showed that, for the period from 1951 to 2007, eutrophication actually led to an increase of DMS emissions much stronger than the response of DMS emissions to ocean acidification.

High-density Integrated Linkage Map Based on SSR Markers in Soybean

Science.gov (United States)

Hwang, Tae-Young; Sayama, Takashi; Takahashi, Masakazu; Takada, Yoshitake; Nakamoto, Yumi; Funatsuki, Hideyuki; Hisano, Hiroshi; Sasamoto, Shigemi; Sato, Shusei; Tabata, Satoshi; Kono, Izumi; Hoshi, Masako; Hanawa, Masayoshi; Yano, Chizuru; Xia, Zhengjun; Harada, Kyuya; Kitamura, Keisuke; Ishimoto, Masao

2009-01-01

A well-saturated molecular linkage map is a prerequisite for modern plant breeding. Several genetic maps have been developed for soybean with various types of molecular markers. Simple sequence repeats (SSRs) are single-locus markers with high allelic variation and are widely applicable to different genotypes. We have now mapped 1810 SSR or sequence-tagged site markers in one or more of three recombinant inbred populations of soybean (the US cultivar ‘Jack’ × the Japanese cultivar ‘Fukuyutaka’, the Chinese cultivar ‘Peking’ × the Japanese cultivar ‘Akita’, and the Japanese cultivar ‘Misuzudaizu’ × the Chinese breeding line ‘Moshidou Gong 503’) and have aligned these markers with the 20 consensus linkage groups (LGs). The total length of the integrated linkage map was 2442.9 cM, and the average number of molecular markers was 90.5 (range of 70–114) for the 20 LGs. We examined allelic diversity for 1238 of the SSR markers among 23 soybean cultivars or lines and a wild accession. The number of alleles per locus ranged from 2 to 7, with an average of 2.8. Our high-density linkage map should facilitate ongoing and future genomic research such as analysis of quantitative trait loci and positional cloning in addition to marker-assisted selection in soybean breeding. PMID:19531560

Effects on parathion on the ecology of a eutrophic aquatic ecosystem: limnocorral experiment

International Nuclear Information System (INIS)

Gasith, A.; Perry, A.S.; Mozel, Y.; Albright, J.L.

1983-01-01

Repetitive exposure of a eutrophic fish pond ecosystem, enclosed in limnocorrals, to 30 ppb parathion resulted in elimination of the potentially dominant zooplankton species, Moina micrura. Consequently, the populations of the rotifers Brachionus and Asplanchna markedly increased. Changes in the zooplankton composition and abundance were followed by increased fluctuations in phytoplankton biomass, phytoplankton photosynthesis, plankton respiration and community metabolism. Similar responses to parathion treatment were observed in previous studies under fish pond conditions. In the presence of fish the effect of parathion on the ecosystem was generally less pronounced and not uniform. The collapse of the zooplankton community and the rapid changes in limnological conditions in the control (untreated) limnocorrals severely limited the duration of the experiment. The results suggest that under eutrophic conditions, small enclosures may be useful for evaluation of the effect of toxicants on the ecosystem only in short term experiments with short lived chemicals. (author)

Predictive modelling of eutrophication in the Pozón de la Dolores lake (Northern Spain) by using an evolutionary support vector machines approach.

Science.gov (United States)

García-Nieto, P J; García-Gonzalo, E; Alonso Fernández, J R; Díaz Muñiz, C

2018-03-01

Eutrophication is a water enrichment in nutrients (mainly phosphorus) that generally leads to symptomatic changes and deterioration of water quality and all its uses in general, when the production of algae and other aquatic vegetations are increased. In this sense, eutrophication has caused a variety of impacts, such as high levels of Chlorophyll a (Chl-a). Consequently, anticipate its presence is a matter of importance to prevent future risks. The aim of this study was to obtain a predictive model able to perform an early detection of the eutrophication in water bodies such as lakes. This study presents a novel hybrid algorithm, based on support vector machines (SVM) approach in combination with the particle swarm optimization (PSO) technique, for predicting the eutrophication from biological and physical-chemical input parameters determined experimentally through sampling and subsequent analysis in a certificate laboratory. This optimization technique involves hyperparameter setting in the SVM training procedure, which significantly influences the regression accuracy. The results of the present study are twofold. In the first place, the significance of each biological and physical-chemical variables on the eutrophication is presented through the model. Secondly, a model for forecasting eutrophication is obtained with success. Indeed, regression with optimal hyperparameters was performed and coefficients of determination equal to 0.90 for the Total phosphorus estimation and 0.92 for the Chlorophyll concentration were obtained when this hybrid PSO-SVM-based model was applied to the experimental dataset, respectively. The agreement between experimental data and the model confirmed the good performance of the latter.

Research into the Eutrophication of an Artificial Playground Lake near the Yangtze River

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Min Pang

2018-03-01

Full Text Available Water pollution in urban rivers is serious in China. Eutrophication and other issues are prominent. Taking the artificial Playground Lake in Zhenjiang as an example, a numerical model combining particle tracing, hydrodynamics, water quality and eutrophication was constructed to simulate the water quality improvement in Playground Lake with or without water diversion by pump and sluice. Simulation results using particle tracking showed that the water residence time depended on wind direction: east wind, 125 h; southeast wind, 115 h; south wind, 95 h. With no water diversion, the lower the flow velocity of Playground Lake under three wind fields, the more serious the eutrophication. Under pump diversion, the water body in Playground Lake can be entirely replaced by water diversion for 30 h. When the temperature is lower than 15 °C, from 15 °C to 25 °C and higher than 25 °C, the water quality can be maintained for 15 d, 10 d and 7 d, respectively. During high tide periods of spring tides in the Yangtze River from June to August, the water can be diverted into the lake through sluices. The greater the Δh (the water head between the Yangtze River and Playground Lake, the more the water quality will improve. Overall, the good-to-bad order of water quality improvements for Playground Lake is as follows: pumping 30 h > sluice diversion > no water diversion. This article is relevant for the environmental management of the artificial Playground Lake, and similar lakes elsewhere.

Linkages among Adolescent Girls' Romantic Relationships, Best Friendships, and Peer Networks

Science.gov (United States)

Kuttler, Ami Flam; La Greca, Annette M.

2004-01-01

This study examined the linkages among girls' best friendships and romantic relationships and accounted for the level of dating involvement as a moderating variable. Social exchange and Sullivan's socioemotional theories served as guides in this process. Questionnaires were administered to 446 girls aged 15-19 years. Results showed that: (a)…

Our evolving conceptual model of the coastal eutrophication problem

Science.gov (United States)

Cloern, James E.

2001-01-01

A primary focus of coastal science during the past 3 decades has been the question: How does anthropogenic nutrient enrichment cause change in the structure or function of nearshore coastal ecosystems? This theme of environmental science is recent, so our conceptual model of the coastal eutrophication problem continues to change rapidly. In this review, I suggest that the early (Phase I) conceptual model was strongly influenced by limnologists, who began intense study of lake eutrophication by the 1960s. The Phase I model emphasized changing nutrient input as a signal, and responses to that signal as increased phytoplankton biomass and primary production, decomposition of phytoplankton-derived organic matter, and enhanced depletion of oxygen from bottom waters. Coastal research in recent decades has identified key differences in the responses of lakes and coastal-estuarine ecosystems to nutrient enrichment. The contemporary (Phase II) conceptual model reflects those differences and includes explicit recognition of (1) system-specific attributes that act as a filter to modulate the responses to enrichment (leading to large differences among estuarine-coastal systems in their sensitivity to nutrient enrichment); and (2) a complex suite of direct and indirect responses including linked changes in: water transparency, distribution of vascular plants and biomass of macroalgae, sediment biogeochemistry and nutrient cycling, nutrient ratios and their regulation of phytoplankton community composition, frequency of toxic/harmful algal blooms, habitat quality for metazoans, reproduction/growth/survival of pelagic and benthic invertebrates, and subtle changes such as shifts in the seasonality of ecosystem functions. Each aspect of the Phase II model is illustrated here with examples from coastal ecosystems around the world. In the last section of this review I present one vision of the next (Phase III) stage in the evolution of our conceptual model, organized around 5

Eutrophication and cyanobacteria in South Africa’s standing water bodies: A view from space

CSIR Research Space (South Africa)

Matthews, MW

2015-05-01

Full Text Available Satellite remote sensing can make a significant contribution to monitoring water quality in South African standing water bodies. Eutrophication, defined as enrichment by nutrients, and toxin-producing cyanobacteria (blue-green algae) blooms pose a...

Is water age a reliable indicator for evaluating water quality effectiveness of water diversion projects in eutrophic lakes?

Science.gov (United States)

Zhang, Xiaoling; Zou, Rui; Wang, Yilin; Liu, Yong; Zhao, Lei; Zhu, Xiang; Guo, Huaicheng

2016-11-01

Water diversion has been applied increasingly to promote the exchange of lake water and to control eutrophication of lakes. The accelerated water exchange and mass transport by water diversion can usually be represented by water age. But the responses of water quality after water diversion is still disputed. The reliability of using water age for evaluating the effectiveness of water diversion projects in eutrophic lakes should be thereby explored further. Lake Dianchi, a semi-closed plateau lake in China, has suffered severe eutrophication since the 1980s, and it is one of the three most eutrophic lakes in China. There was no significant improvement in water quality after an investment of approximately 7.7 billion USD and numerous project efforts from 1996 to 2015. After the approval of the Chinese State Council, water has been transferred to Lake Dianchi to alleviate eutrophication since December 2013. A three-dimensional hydrodynamic and water quality model and eight scenarios were developed in this study to quantity the influence of this water diversion project on water quality in Lake Dianchi. The model results showed that (a) Water quality (TP, TN, and Chla) could be improved by 13.5-32.2%, much lower than the approximate 50% reduction in water age; (b) Water exchange had a strong positive relationship with mean TP, and mean Chla had exactly the same response to water diversion as mean TN; (c) Water level was more beneficial for improving hydrodynamic and nutrient concentrations than variation in the diverted inflowing water volume; (d) The water diversion scenario of doubling the diverted inflow rate in the wet season with the water level of 1886.5 m and 1887 m in the remaining months was the best water diversion mode for mean hydrodynamics and TP, but the scenario of doubling the diverted inflow rate in the wet season with 1887 m throughout the year was optimum for mean TN and Chla; (e) Water age influenced the effectiveness of water diversion on the

Approaches for integrated assessment of ecological and eutrophication status of surface waters in Nordic Countries

DEFF Research Database (Denmark)

Andersen, Jesper H.; Aroviita, Jukka; Carstensen, Jacob

2016-01-01

We review approaches and tools currently used in Nordic countries (Denmark, Finland, Norway and Sweden) for integrated assessment of ‘ecological status’ sensu the EU Water Framework Directive as well as assessment of ‘eutrophication status’ in coastal and marine waters. Integration principles for...... principles applied within BQEs are critical and in need of harmonisation if we want a better understanding of potential transition in ecological status between surface water types, e.g. when riverine water enters a downstream lake or coastal water body.......We review approaches and tools currently used in Nordic countries (Denmark, Finland, Norway and Sweden) for integrated assessment of ‘ecological status’ sensu the EU Water Framework Directive as well as assessment of ‘eutrophication status’ in coastal and marine waters. Integration principles...

IFPE/GBGI, Grain-Bubble Gas Inter-linkage

International Nuclear Information System (INIS)

2007-01-01

Description: The fuel microstructure examination at the thermocouple tips in the lower and upper part of a steady-state irradiated experimental fuel rod with different as fabricated fuel-to-clad gaps in these two regions revealed on-set of grain boundary gas bubble precipitation in the fuel center of the small-gap/low-temperature region (lower part) and developed inter-linkage in the fuel center of the large-gap/high-temperature region (upper part). By use of a diffusion model and the measured temperatures, corresponding grain boundary gas 'concentrations' were calculated

Finding The Baseline--Putting Recent Eutrophication Of Two South Texas Coastal Water Bodies Into Perspective By Using Sedimentary Records To Examine The Long-Term, Natural Variability Of The Systems

Science.gov (United States)

Besonen, M. R.; Zimba, P.; Hill, E.; Tissot, P.; Mckay, M.; Silliman, J.

2013-12-01

reservoirs along the Nueces River, the primary inflow for the system. The lack of long-term environmental monitoring records makes it difficult to disentangle the complex interrelationships between the natural and anthropogenic factors that have contributed to eutrophication. To address this issue, we are examining proxy evidence from sediment cores to look back in time, and understand the true baseline conditions and natural variability of these systems long before they were affected by anthropogenic impacts. We are using a suite of geological, chemical, and biological indicators including color spectral reflectance (for total chlorophyll content), organic carbon content via loss-on-ignition, Terrigenous/Aquatic Ratio (TARHC), TOC, C/N ratio analysis, pigment analysis via HPLC, and microfossil assemblage analysis. Age control for the stratigraphy will be provided by radiometric age analyses using 137Cs, 210Pb, and 14C. Initial results from spectral reflectance scanning of sediment cores from the Nueces Estuary appear to indicate an increased chlorophyll content up core, which probably reflects a long-term increase of primary productivity in the system.

Contribution of Spartina maritima to the reduction of eutrophication in estuarine systems

International Nuclear Information System (INIS)

Sousa, Ana I.; Lillebo, Ana I.; Cacador, Isabel; Pardal, Miguel A.

2008-01-01

Salt marshes are among the most productive ecosystems in the world, performing important ecosystem functions, particularly nutrient recycling. In this study, a comparison is made between Mondego and Tagus estuaries in relation to the role of Spartina maritima in nitrogen retention capacity and cycling. Two mono-specific S. maritima stands per estuary were studied during 1 yr (biomass, nitrogen (N) pools, litter production, decomposition rates). Results showed that the oldest Tagus salt marsh population presented higher annual belowground biomass and N productions, and a slower decomposition rate for litter, contributing to the higher N accumulation in the sediment, whereas S. maritima younger marshes had higher aboveground biomass production. Detritus moved by tides represented a huge amount of aboveground production, probably significant when considering the N balance of these salt marshes. Results reinforce the functions of salt marshes as contributing to a reduction of eutrophication in transitional waters, namely through sedimentation processes. - The crucial capacity of salt marshes to retain nitrogen, thus reducing eutrophication, greatly depends on the salt marsh maturity, rather than the estuarine system

Long-term effects of extreme weather events and eutrophication on the fish community of shallow Lake Peipsi (Estonia/Russia

Directory of Open Access Journals (Sweden)

Külli Kangur

2013-06-01

Full Text Available The fish kill in lake Peipsi (Estonia/Russia during the extraordinarily hot summer of 2010 evoked an investigation into the effects of environmental extremes and long-term eutrophication on the fish community of the lake. Current data on lake Peipsi indicate that temperature extremes and synergistic interactions with eutrophication have led to a radical restructuring of the fish community. Commercial landings of lake smelt, Osmerus eperlanus eperlanus m. spirinchus (Pallas, the previous dominant species of the fish community, have decreased dramatically since the 1930s, these declines being coupled with summer heat waves coinciding with low water levels. Gradual decline in smelt stock and catches was significantly related to a decline of near-bottom oxygen conditions and to a decrease in water transparency. The first documented fish kill in 1959 occurred only in the southern, most shallow and eutrophic lake (lake Pihkva. Recently, summer fish kill have become more frequent, involving larger areas of the lake. In addition to the cold-water species, e.g. smelt and vendace Coregonus albula (L., the abundance of bottom-dwelling fishes such as ruffe Gymnocephalus cernuus (L. and juvenile fish have significantly decreased after the 2010 heat wave probably due to hypoxia and warm water temperatures. This study showed that fish community structure in large shallow lakes may be very vulnerable to water temperature increases, especially temperature extremes in combination with eutrophication.

ANALYSIS OF INTER SECTORAL LINKAGES IN SEMARANG REGENCY

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Fafurida

2014-03-01

Full Text Available This research aims to analyze inter economic sectoral linkages and to arrange the Klassen typology of economic sectors in Semarang Regency. The Klassen typology is composed from the result of the linkage analysis. To construct the analysis, this paper also utulizes the input-output analysis. It finds that service sector has the highest backward linkage while farming sector has the highest forward linkage. Based on the Klassen typology analysis, sectors with the highest backward and forward linkages and potential to be the leading sector are farming sector, dan trade, hotel and restaurant sector.Keywords: Backward linkage,forward linkage, Klassen typologyJEL classification number: R15, O21AbstrakPenelitian ini bertujuan untuk mengkaji seberapa besar keterkaitan antar sektor ekonomi di Kabupaten Semarang dan memetakan tipologi Klassennya. Tipologi Klasen disusun berdasarkan hasil perhitungan analisis keterkaitannya. Untuk menyusun analisis tersebut, paper ini juga menggunakan analisis input-output. Hasil penelitian menunjukkan bahwa sektor jasa memiliki keterkaitan ke belakang tertinggi dibandingkan dengan sektor lainnya. Sementara itu, sektor pertanian merupakan sektor yang memiliki keterkaitan ke depan tertinggi. Berdasarkan hasil analisis tipologi Klassen, sektor yang memiliki keterkaitan ke depan dan ke belakang yang tinggi dan dapat menjadi sektor unggulan adalah sektor perdagangan, hotel dan sektor restoran.Kata kunci: Keterkaitan ke belakang, keterkaitan ke depan, tipologi KlassenJEL classification numbers: R15, O21

Posterior probability of linkage and maximal lod score.

Science.gov (United States)

Génin, E; Martinez, M; Clerget-Darpoux, F

1995-01-01

To detect linkage between a trait and a marker, Morton (1955) proposed to calculate the lod score z(theta 1) at a given value theta 1 of the recombination fraction. If z(theta 1) reaches +3 then linkage is concluded. However, in practice, lod scores are calculated for different values of the recombination fraction between 0 and 0.5 and the test is based on the maximum value of the lod score Zmax. The impact of this deviation of the test on the probability that in fact linkage does not exist, when linkage was concluded, is documented here. This posterior probability of no linkage can be derived by using Bayes' theorem. It is less than 5% when the lod score at a predetermined theta 1 is used for the test. But, for a Zmax of +3, we showed that it can reach 16.4%. Thus, considering a composite alternative hypothesis instead of a single one decreases the reliability of the test. The reliability decreases rapidly when Zmax is less than +3. Given a Zmax of +2.5, there is a 33% chance that linkage does not exist. Moreover, the posterior probability depends not only on the value of Zmax but also jointly on the family structures and on the genetic model. For a given Zmax, the chance that linkage exists may then vary.

Preimplantation genetic diagnosis of X-linked diseases examined by indirect linkage analysis.

Science.gov (United States)

Borgulova, I; Putzova, M; Soldatova, I; Krautova, L; Pecnova, L; Mika, J; Kren, R; Potuznikova, P; Stejskal, D

2015-01-01

Many centers of assisted reproduction in the Czech Republic offer preimplantation genetic diagnosis with fluorescent in situ hybridization (FISH) to couples requiring preimplantation genetic diagnosis (PGD) of X-linked diseases. However, this process results in discarding all male embryos and is not able to distinguish a carrier or healthy female embryo in X-linked recessive disorders. The main aim of this study was to summarize a six-year period of PGD of X-linked monogenic diseases using indirect linkage analysis. We wanted to accentuate the advantage indirect analysis of PGD using multiple displacement amplification (MDA) followed by short tandem repeat (STR) analysis. We present forty-six PGD cycles, including pre-case haplotyping (PGH) panel, for fifteen X-linked diseases. Embryo transfer was made thirty-eight times and gravidity was confirmed in thirteen female probands with a success rate of pregnancy calculated at 42 %. PGD procedure using MDA amplification followed by STR analysis provides help in identifying genetic defects within embryos prior to implantation. The reliability of the method was also supported by high pregnancy rate compared to other publications, which commonly achieved a 30-35 % success rate (Tab. 2, Fig. 1, Ref. 33).

Metabolic and clinical comparative analysis of treadmill six-minute walking test and cardiopulmonary exercise testing in obese and eutrophic women

Directory of Open Access Journals (Sweden)

Luciana Di Thommazo-Luporini

Full Text Available BACKGROUND: Impaired exercise tolerance is directly linked to decreased functional capacity as a consequence of obesity. OBJECTIVES: To analyze and compare the cardiopulmonary, metabolic, and perceptual responses during a cardiopulmonary exercise test (CPX and a treadmill six-minute walking test (tread6MWT in obese and eutrophic women. METHOD: Twenty-nine female participants, aged 20-45 years were included. Fourteen were allocated to the obese group and 15 to the eutrophic group. Anthropometric measurements and body composition assessment were performed. RESULTS: In both tests, obese women presented with significantly higher absolute oxygen uptake, minute ventilation, and systolic and diastolic blood pressure; they also presented with lower speed, distance walked, and oxygen uptake corrected by the weight compared to eutrophics. During the maximal exercise test, perceived dyspnea was greater and the respiratory exchange ratio was lower in obese subjects compared to eutrophics. During the submaximal test, carbon dioxide production, tidal volume, and heart rate were higher in obese subjects compared to eutrophic women. When analyzing possible correlations between the CPX and the tread6MWT at peak, there was a strong correlation for the variable heart rate and a moderate correlation for the variable oxygen uptake. The heart rate obtained in the submaximal test was able to predict the one obtained in the maximal test. Bland-Altman plots demonstrated the agreement between both tests to identify metabolic and physiological parameters at peak exercise. CONCLUSIONS: The six-minute walking test induced ventilatory, metabolic, and cardiovascular responses in agreement with the maximal testing. Thus, the six-minute walking test proves to be important for functional evaluation in the physical therapy routine.

The physiological and biochemical mechanism of nitrate-nitrogen removal by water hyacinth from agriculture eutrophic wastewater

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WU Wenwei

Full Text Available ABSTRACT Large amount of agriculturl wastewater containing high level nitrate-nitrogen (NO3 --N is produced from modern intensive agricultural production management due to the excessive use of chemical fertilizers and livestock scale farming. The hydroponic experiment of water hyacinth was conducted for analyzing the content of NO3 --N, soluble sugar content, N-transported the amino acid content and growth change in water hyacinth to explore its purification ability to remove NO3 --N from agriculture eutrophic wastewater and physiological and biochemical mechanism of this plant to remove NO3 --N. The results showed that the water hyacinth could effectively utilize the NO3 --N from agriculture eutrophic wastewater. Compared with the control, the contents of NO3 -change to NO3 --N in the root, leaf petiole and leaf blade of water hyacinth after treatment in the wastewater for a week was significantly higher than that in the control plants treated with tap water, and also the biomass of water hyacinth increased significantly, indicating that the accumulation of biomass due to the rapid growth of water hyacinth could transfer some amount of NO3 --N.13C-NMR analysis confirmed that water hyacinth would convert the part nitrogen absorbed from agriculture eutrophic wastewater to ammonia nitrogen, which increased the content of aspartic acid and glutamic acid, decreased the content of soluble sugar, sucrose and fructose and the content of N-storaged asparagine and glutamine, lead to enhance the synthesis of plant amino acids and promote the growth of plants. These results indicate that the nitrate in agriculture eutrophic wastewater can be utilized by water hyacinth as nitrogen nutrition, and can promote plant growth by using soluble sugar and amide to synthesis amino acids and protein.

Linkage and related analyses of Barrett's esophagus and its associated adenocarcinomas.

Science.gov (United States)

Sun, Xiangqing; Elston, Robert; Falk, Gary W; Grady, William M; Faulx, Ashley; Mittal, Sumeet K; Canto, Marcia I; Shaheen, Nicholas J; Wang, Jean S; Iyer, Prasad G; Abrams, Julian A; Willis, Joseph E; Guda, Kishore; Markowitz, Sanford; Barnholtz-Sloan, Jill S; Chandar, Apoorva; Brock, Wendy; Chak, Amitabh

2016-07-01

Familial aggregation and segregation analysis studies have provided evidence of a genetic basis for esophageal adenocarcinoma (EAC) and its premalignant precursor, Barrett's esophagus (BE). We aim to demonstrate the utility of linkage analysis to identify the genomic regions that might contain the genetic variants that predispose individuals to this complex trait (BE and EAC). We genotyped 144 individuals in 42 multiplex pedigrees chosen from 1000 singly ascertained BE/EAC pedigrees, and performed both model-based and model-free linkage analyses, using S.A.G.E. and other software. Segregation models were fitted, from the data on both the 42 pedigrees and the 1000 pedigrees, to determine parameters for performing model-based linkage analysis. Model-based and model-free linkage analyses were conducted in two sets of pedigrees: the 42 pedigrees and a subset of 18 pedigrees with female affected members that are expected to be more genetically homogeneous. Genome-wide associations were also tested in these families. Linkage analyses on the 42 pedigrees identified several regions consistently suggestive of linkage by different linkage analysis methods on chromosomes 2q31, 12q23, and 4p14. A linkage on 15q26 is the only consistent linkage region identified in the 18 female-affected pedigrees, in which the linkage signal is higher than in the 42 pedigrees. Other tentative linkage signals are also reported. Our linkage study of BE/EAC pedigrees identified linkage regions on chromosomes 2, 4, 12, and 15, with some reported associations located within our linkage peaks. Our linkage results can help prioritize association tests to delineate the genetic determinants underlying susceptibility to BE and EAC.

Testing association and linkage using affected-sib-parent study designs.

Science.gov (United States)

Millstein, Joshua; Siegmund, Kimberly D; Conti, David V; Gauderman, W James

2005-11-01

We have developed a method for jointly testing linkage and association using data from affected sib pairs and their parents. We specify a conditional logistic regression model with two covariates, one that quantifies association (either direct association or indirect association via linkage disequilibrium), and a second that quantifies linkage. The latter covariate is computed based on expected identity-by-descend (ibd) sharing of marker alleles between siblings. In addition to a joint test of linkage and association, our general framework can be used to obtain a linkage test comparable to the mean test (Blackwelder and Elston [1985] Genet. Epidemiol. 2:85-97), and an association test comparable to the Family-Based Association Test (FBAT; Rabinowitz and Laird [2000] Hum. Hered. 50:211-223). We present simulation results demonstrating that our joint test can be more powerful than some standard tests of linkage or association. For example, with a relative risk of 2.7 per variant allele at a disease locus, the estimated power to detect a nearby marker with a modest level of LD was 58.1% by the mean test (linkage only), 69.8% by FBAT, and 82.5% by our joint test of linkage and association. Our model can also be used to obtain tests of linkage conditional on association and association conditional on linkage, which can be helpful in fine mapping. Copyright 2005 Wiley-Liss, Inc.

Examination of X chromosome markers in Rett syndrome: Exclusion mapping with a novel variation on multilocus linkage analysis

Energy Technology Data Exchange (ETDEWEB)

Ellison, K.A.; Fill, C.P. (Baylor College of Medicine, Houston, TX (United States)); Terwililger, J.; Percy, A.K.; Zobhbi, H. (Columbia University, NY (United States)); DeGennaro, L.J.; Ott, J. (University of Massachusetts Medical School, Worcester (United States)); Anvret, M.; Martin-Gallardo, A. (National Institutes of Health, Bethesda, MD (United States))

1992-02-01

Rett syndrome is a neurologic disorder characterized by early normal development followed by regression, acquired deceleration of head growth, autism, ataxia, and sterotypic hand movements. The exclusive occurrence of the syndrome in females and the occurrence of a few familial cases with inheritance through maternal lines suggest that this disorder is most likely secondary to a mutation on the X chromosome. To address this hypothesis and to identify candidate regions for the Rett syndrome gene locus, genotypic analysis was performed in two families with maternally related affected half-sisters by using 63 DNA markers from the X chromosome. Nineteen of the loci studied were chosen for multipoint linkage analysis because they have been previously genetically mapped using a large number of meioses from reference families. Using the exclusion criterion of a lod score less than [minus]2, the authors were able to exclude the region between the Duchenne muscular dystrophy locus and the DXS456 locus. This region extends from Xp21.2 to Xq21-q23. The use of the multipoint linkage analysis approach outlined in this study should allow the exclusion of additional regions of the X chromosome as new markers are analyzed.

The management of nutrients and potential eutrophication in estuaries and other restricted water bodies

NARCIS (Netherlands)

Elliott, M; de Jonge, V.N.

Conceptual models are derived to indicate the signs and symptoms inherent in nutrient changes to brackish, estuarine and coastal areas of restricted circulation. These give a structured approach to detecting adverse symptoms of hypernutrification and eutrophication at all levels of biological

A node linkage approach for sequential pattern mining.

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Osvaldo Navarro

Full Text Available Sequential Pattern Mining is a widely addressed problem in data mining, with applications such as analyzing Web usage, examining purchase behavior, and text mining, among others. Nevertheless, with the dramatic increase in data volume, the current approaches prove inefficient when dealing with large input datasets, a large number of different symbols and low minimum supports. In this paper, we propose a new sequential pattern mining algorithm, which follows a pattern-growth scheme to discover sequential patterns. Unlike most pattern growth algorithms, our approach does not build a data structure to represent the input dataset, but instead accesses the required sequences through pseudo-projection databases, achieving better runtime and reducing memory requirements. Our algorithm traverses the search space in a depth-first fashion and only preserves in memory a pattern node linkage and the pseudo-projections required for the branch being explored at the time. Experimental results show that our new approach, the Node Linkage Depth-First Traversal algorithm (NLDFT, has better performance and scalability in comparison with state of the art algorithms.

Algal bloom sedimentation induces variable control of lake eutrophication by phosphorus inactivating agents

Energy Technology Data Exchange (ETDEWEB)

Wang, Changhui [State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 (China); Bai, Leilei [State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 (China); Graduate University of Chinese Academy of Sciences (China); Jiang, He-Long, E-mail: hljiang@niglas.ac.cn [State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 (China); Xu, Huacheng [State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 (China)

2016-07-01

Lake eutrophication typically occurs with a syndrome of algae breeding and biomass accumulation (e.g., algal blooms). Therefore, the effect of algal bloom sedimentation on eutrophication control by phosphorus (P) inactivating agents was assessed herein. Three commercial products, including aluminum (Al) sulfate, iron (Fe) sulfate, and a lanthanum-modified clay (Phoslock®), as well as one easily available by-product, drinking water treatment residue (DWTR), were selected. The most important finding was that during algae sedimentation, P immobilization from the overlying water by Al, Phoslock®, and DWTR was dominated by a long-term slow phase (> 150 d), while Fe has limited effectiveness on the immobilization. Further analysis indicated that the algae sedimentation effect was mainly due to the slow release of P from algae, leading to relatively limited P available for the inactivating agents. Then, a more unfavorable effect on the P immobilization capability of inactivating agents was caused by the induced anaerobic conditions, the released organic matter from algae, and the increased sulfide in the overlying water and sediments during sedimentation. Overall, algae sedimentation induced variable control of eutrophication by P inactivating agents. Accordingly, recommendations for future works about algal lake restoration were also proposed. - Highlights: • A long-term P immobilization by Phoslock®, DWTR, and Al was observed. • Fe had limited effectiveness on P pollution control for overlying water. • Al and Fe enhanced sulfur reduction, while DWTR and Phoslock® had minor effect. • The sedimentation reduced Al and La release from agents, but enhanced Fe release. • The agents changed organic matter compositions and structures in water columns.

Algal bloom sedimentation induces variable control of lake eutrophication by phosphorus inactivating agents

International Nuclear Information System (INIS)

Wang, Changhui; Bai, Leilei; Jiang, He-Long; Xu, Huacheng

2016-01-01

Lake eutrophication typically occurs with a syndrome of algae breeding and biomass accumulation (e.g., algal blooms). Therefore, the effect of algal bloom sedimentation on eutrophication control by phosphorus (P) inactivating agents was assessed herein. Three commercial products, including aluminum (Al) sulfate, iron (Fe) sulfate, and a lanthanum-modified clay (Phoslock®), as well as one easily available by-product, drinking water treatment residue (DWTR), were selected. The most important finding was that during algae sedimentation, P immobilization from the overlying water by Al, Phoslock®, and DWTR was dominated by a long-term slow phase (> 150 d), while Fe has limited effectiveness on the immobilization. Further analysis indicated that the algae sedimentation effect was mainly due to the slow release of P from algae, leading to relatively limited P available for the inactivating agents. Then, a more unfavorable effect on the P immobilization capability of inactivating agents was caused by the induced anaerobic conditions, the released organic matter from algae, and the increased sulfide in the overlying water and sediments during sedimentation. Overall, algae sedimentation induced variable control of eutrophication by P inactivating agents. Accordingly, recommendations for future works about algal lake restoration were also proposed. - Highlights: • A long-term P immobilization by Phoslock®, DWTR, and Al was observed. • Fe had limited effectiveness on P pollution control for overlying water. • Al and Fe enhanced sulfur reduction, while DWTR and Phoslock® had minor effect. • The sedimentation reduced Al and La release from agents, but enhanced Fe release. • The agents changed organic matter compositions and structures in water columns.

Privacy-preserving record linkage on large real world datasets.

Science.gov (United States)

Randall, Sean M; Ferrante, Anna M; Boyd, James H; Bauer, Jacqueline K; Semmens, James B

2014-08-01

Record linkage typically involves the use of dedicated linkage units who are supplied with personally identifying information to determine individuals from within and across datasets. The personally identifying information supplied to linkage units is separated from clinical information prior to release by data custodians. While this substantially reduces the risk of disclosure of sensitive information, some residual risks still exist and remain a concern for some custodians. In this paper we trial a method of record linkage which reduces privacy risk still further on large real world administrative data. The method uses encrypted personal identifying information (bloom filters) in a probability-based linkage framework. The privacy preserving linkage method was tested on ten years of New South Wales (NSW) and Western Australian (WA) hospital admissions data, comprising in total over 26 million records. No difference in linkage quality was found when the results were compared to traditional probabilistic methods using full unencrypted personal identifiers. This presents as a possible means of reducing privacy risks related to record linkage in population level research studies. It is hoped that through adaptations of this method or similar privacy preserving methods, risks related to information disclosure can be reduced so that the benefits of linked research taking place can be fully realised. Copyright © 2013 Elsevier Inc. All rights reserved.

A comparison of genetic map distance and linkage disequilibrium between 15 polymorphic dinucleotide repeat loci in two populations

Energy Technology Data Exchange (ETDEWEB)

Urbanek, M.; Goldman, D.; Long, J.C. [Lab. of Neurogenetics, Rockville, MD (United States)

1994-09-01

Linkage disequilibrium has recently been used to map the diastrophic dysplasia gene in a Finnish sample. One advantage of this method is that the large pedigrees required by some other methods are unnecessary. Another advantage is that linkage disequilibrium mapping capitalizes on the cumulative history of recombination events, rather than those occurring within the sampled individuals. A potential limitation of linkage disequilibrium mapping is that linkage equilibrium is likely to prevail in all but the most isolated populations, e.g., those which have recently experienced founder effects or severe population bottlenecks. In order to test the method`s generality, we examined patterns of linkage disequilibrium between pairs of loci within a known genetic map. Two populations were analyzed. The first population, Navajo Indians (N=45), is an isolate that experienced a severe bottleneck in the 1860`s. The second population, Maryland Caucasians (N=45), is cosmopolitan. We expected the Navajo sample to display more linkage disequilibrium than the Caucasian sample, and possibly that the Navajo disequilibrium pattern would reflect the genetic map. Linkage disequilibrium coefficients were estimated between pairs of alleles at different loci using maximum likelihood. The genetic isolate structure of Navajo Indians is confirmed by the DNA typings. Heterozygosity is lower than in the Caucasians, and fewer different alleles are observed. However, a relationship between genetic map distance and linkage disequilibrium could be discerned in neither the Navajo nor the Maryland samples. Slightly more linkage disequilibrium was observed in the Navajos, but both data sets were characterized by very low disequilibrium levels. We tentatively conclude that linkage disequilibrium mapping with dinucleotide repeats will only be useful with close linkage between markers and diseases, even in very isolated populations.

Seagrasses and Eutrophication : Interactions between seagrass photosynthesis, epiphytes, macroalgae and mussels

OpenAIRE

Mvungi, Esther Francis

2011-01-01

Seagrass meadows are highly productive, ecologically and economically valuable ecosystems. However, increased human activities along the coastal areas leading to processes such as eutrophication have resulted in the rapid loss and deterioration of seagrass ecosystems worldwide. This thesis focuses on the responses of seagrasses to increases in nutrients, subsequent increases in ephemeral algae, and changes in the physical-chemical properties of seawater induced by interaction with other marin...

Landward Perspective of Coastal Eutrophication Potential Under Future Climate Change: The Seine River Case (France

Directory of Open Access Journals (Sweden)

Mélanie Raimonet

2018-05-01

Full Text Available Studies quantifying the impact of climate change have so far mostly examined atmospheric variables, and few are evaluating the cascade of aquatic impacts that will occur along the land–ocean continuum until the ultimate impacts on coastal eutrophication potential. In this study, a new hydro-biogeochemical modeling chain has been developed, based on the coupling of the generic pyNuts-Riverstrahler biogeochemical model and the GR4J-CEMANEIGE hydrological model, and applied to the Seine River basin (France. Averaged responses of biogeochemical variables to climate-induced hydrological changes were assessed using climate forcing based on 12 projections of precipitation and temperature (BC-CORDEX for the stabilization (RCP 4.5 and the increasing (RCP 8.5 CO2 emission scenarios. Beyond the amount of nutrients delivered to the sea, we calculated the indicator of coastal eutrophication potential (ICEP. The models run with the RCP4.5 stabilization scenario show low variations in hydrological regimes and water quality, while five of the six models run with the increasing CO2 emissions scenario (RCP8.5 leads to more intense extreme streamflow (i.e., higher maximum flows, lower and longer minimum flows, resulting in the degradation of water quality. For the driest RCP 8.5 projection, median biogeochemical impacts induced by decreasing discharge (until −270 m3 s−1 in average are mostly located downstream of major wastewater treatment plants. During spring bloom, e.g., in May, the associated higher residence time leads to an increase of phytoplankton biomass (+31% in average, with a simultaneous −23% decrease of silicic acid, followed downstream by a −9% decrease of oxygen. Later during low flow, major increases in nitrate and phosphate concentrations (until +19% and +32% in average are expected. For all considered scenarios, high ICEP values (above zero lasted, indicating that coastal eutrophication is not expected to decrease with changing

High primary production contrasts with intense carbon emission in a eutrophic tropical reservoir

NARCIS (Netherlands)

Almeida, Rafael M.; Nóbrega, Gabriel N.; Junger, Pedro C.; Figueiredo, Aline V.; Andrade, Anízio S.; Moura, de Caroline G.B.; Tonetta, Denise; Oliveira, Ernandes S.; Araújo, Fabiana; Rust, Felipe; Piñeiro-Guerra, Juan M.; Mendonça, Jurandir R.; Medeiros, Leonardo R.; Pinheiro, Lorena; Miranda, Marcela; Costa, Mariana R.A.; Melo, Michaela L.; Nobre, Regina L.G.; Benevides, Thiago; Roland, Fábio; Klein, de Jeroen; Barros, Nathan O.; Mendonça, Raquel; Becker, Vanessa; Huszar, Vera L.M.; Kosten, Sarian

2016-01-01

Recent studies from temperate lakes indicate that eutrophic systems tend to emit less carbon dioxide (CO₂) and bury more organic carbon (OC) than oligotrophic ones, rendering them CO₂ sinks in some cases. However, the scarcity of data from tropical systems is critical for a

Adiponectin in eutrophic and obese children as a biomarker to predict metabolic syndrome and each of its components

Directory of Open Access Journals (Sweden)

Klünder-Klünder Miguel

2013-01-01

Full Text Available Abstract Background Obesity is associated with the rise of noncommunicable diseases worldwide. The pathophysiology behind this disease involves the increase of adipose tissue, being inversely related to adiponectin, but directly related to insulin resistance and metabolic syndrome (MetS. Therefore, this study aimed to determine the relationship between adiponectin levels with each component of MetS in eutrophic and obese Mexican children. Methods A cross sectional study was conducted in 190 school-age children classified as obese and 196 classified as eutrophic. Adiponectin, glucose, insulin, high density lipoprotein cholesterol (HDL-C and triglycerides were determined from a fasting blood sample. Height, weight, waist circumference, systolic and diastolic blood pressures (BP were measured; MetS was evaluated with the IDF definition. The study groups were divided according to tertiles of adiponectin, using the higher concentration as a reference. Linear regression analysis was used to assess the association between adiponectin and components of the MetS. Finally, stepwise forward multiple logistic regression analysis controlling for age, gender, basal HOMA-IR values and BMI was performed to determine the odds ratio of developing MetS according to adiponectin tertiles. Results Anthropometric and metabolic measurements were statistically different between eutrophic and obese children with and without MetS (P Conclusion In this sample of eutrophic and obese Mexican children we found that adiponectin concentrations and MetS components have an inversely proportional relationship, which supports the idea that this hormone could be a biomarker for identifying individuals with risk of developing MetS.

Genome-wide linkage analysis for human longevity

DEFF Research Database (Denmark)

Beekman, Marian; Blanché, Hélène; Perola, Markus

2013-01-01

Clear evidence exists for heritability of human longevity, and much interest is focused on identifying genes associated with longer lives. To identify such longevity alleles, we performed the largest genome-wide linkage scan thus far reported. Linkage analyses included 2118 nonagenarian Caucasian...

Eutrophication potential of lakes: an integrated analysis of trophic state, morphometry, land occupation, and land use

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RF Silvino

Full Text Available AbstractDespite being inside a protected area, Lake Sumidouro has been impacted by the anthropogenic occupation of the surrounding area since the 1970’s, compromising the ecological integrity of the lake and the sustainable use of natural resources. This study examined the current trophic classification of the lake and developed methods for improving it through an integrated analysis of morphometric and limnological parameters, land use and land occupation in the watershed, and eutrophication potential. Data for the limnological parameters, land use and land occupation, and morphometric characteristics of Lake Sumidouro were collected in the rainy and dry seasons of 2009 and 2010. Depending on the trophic classification system used, Lake Sumidouro is classified as oligotrophic to hypereutrophic. In our study, the highest concentration of nutrients occurred in the rainy season, indicating that high nutrient inputs played an important role during this period. Areas of anthropogenic occupation comprised approximately 62.9% of the total area of the watershed, with pasture and urban settlement as the main types of land use. The influent total phosphorus load was estimated to be 15,824.3 kg/year. To maintain mesotrophic conditions, this load must be reduced by 29.4%. By comparing the isolated use of trophic state indices, this study demonstrated that comparing the trophic state classification with morphometric analyses, land use and land occupation types in the watershed, and potential phosphorus load provided better information to guide management actions for restoration and conservation. Furthermore, this approach also allowed for evaluating the vulnerability of the environment to the eutrophication process.

Integrated water quality, emergy and economic evaluation of three bioremediation treatment systems for eutrophic water

Science.gov (United States)

This study was targeted at finding one or more environmentally efficient, economically feasible and ecologically sustainable bioremediation treatment modes for eutrophic water. Three biological species, i.e. water spinach (Ipomoea aquatica), loach (Misgurus anguillicaudatus) and ...

Fine mapping quantitative trait loci under selective phenotyping strategies based on linkage and linkage disequilibrium criteria

DEFF Research Database (Denmark)

Ansari-Mahyari, S; Berg, P; Lund, M S

2009-01-01

disequilibrium-based sampling criteria (LDC) for selecting individuals to phenotype are compared to random phenotyping in a quantitative trait loci (QTL) verification experiment using stochastic simulation. Several strategies based on LAC and LDC for selecting the most informative 30%, 40% or 50% of individuals...... for phenotyping to extract maximum power and precision in a QTL fine mapping experiment were developed and assessed. Linkage analyses for the mapping was performed for individuals sampled on LAC within families and combined linkage disequilibrium and linkage analyses was performed for individuals sampled across...... the whole population based on LDC. The results showed that selecting individuals with similar haplotypes to the paternal haplotypes (minimum recombination criterion) using LAC compared to random phenotyping gave at least the same power to detect a QTL but decreased the accuracy of the QTL position. However...

Estimating parameters for probabilistic linkage of privacy-preserved datasets.

Science.gov (United States)

Brown, Adrian P; Randall, Sean M; Ferrante, Anna M; Semmens, James B; Boyd, James H

2017-07-10

Probabilistic record linkage is a process used to bring together person-based records from within the same dataset (de-duplication) or from disparate datasets using pairwise comparisons and matching probabilities. The linkage strategy and associated match probabilities are often estimated through investigations into data quality and manual inspection. However, as privacy-preserved datasets comprise encrypted data, such methods are not possible. In this paper, we present a method for estimating the probabilities and threshold values for probabilistic privacy-preserved record linkage using Bloom filters. Our method was tested through a simulation study using synthetic data, followed by an application using real-world administrative data. Synthetic datasets were generated with error rates from zero to 20% error. Our method was used to estimate parameters (probabilities and thresholds) for de-duplication linkages. Linkage quality was determined by F-measure. Each dataset was privacy-preserved using separate Bloom filters for each field. Match probabilities were estimated using the expectation-maximisation (EM) algorithm on the privacy-preserved data. Threshold cut-off values were determined by an extension to the EM algorithm allowing linkage quality to be estimated for each possible threshold. De-duplication linkages of each privacy-preserved dataset were performed using both estimated and calculated probabilities. Linkage quality using the F-measure at the estimated threshold values was also compared to the highest F-measure. Three large administrative datasets were used to demonstrate the applicability of the probability and threshold estimation technique on real-world data. Linkage of the synthetic datasets using the estimated probabilities produced an F-measure that was comparable to the F-measure using calculated probabilities, even with up to 20% error. Linkage of the administrative datasets using estimated probabilities produced an F-measure that was higher

RLT-S: A Web System for Record Linkage.

Directory of Open Access Journals (Sweden)

Abdullah-Al Mamun

Full Text Available Record linkage integrates records across multiple related data sources identifying duplicates and accounting for possible errors. Real life applications require efficient algorithms to merge these voluminous data sources to find out all records belonging to same individuals. Our recently devised highly efficient record linkage algorithms provide best-known solutions to this challenging problem.We have developed RLT-S, a freely available web tool, which implements our single linkage clustering algorithm for record linkage. This tool requires input data sets and a small set of configuration settings about these files to work efficiently. RLT-S employs exact match clustering, blocking on a specified attribute and single linkage based hierarchical clustering among these blocks.RLT-S is an implementation package of our sequential record linkage algorithm. It outperforms previous best-known implementations by a large margin. The tool is at least two times faster for any dataset than the previous best-known tools.RLT-S tool implements our record linkage algorithm that outperforms previous best-known algorithms in this area. This website also contains necessary information such as instructions, submission history, feedback, publications and some other sections to facilitate the usage of the tool.RLT-S is integrated into http://www.rlatools.com, which is currently serving this tool only. The tool is freely available and can be used without login. All data files used in this paper have been stored in https://github.com/abdullah009/DataRLATools. For copies of the relevant programs please see https://github.com/abdullah009/RLATools.

Linkage analysis: Inadequate for detecting susceptibility loci in complex disorders?

Energy Technology Data Exchange (ETDEWEB)

Field, L.L.; Nagatomi, J. [Univ. of Calgary, Alberta (Canada)

1994-09-01

Insulin-dependent diabetes mellitus (IDDM) may provide valuable clues about approaches to detecting susceptibility loci in other oligogenic disorders. Numerous studies have demonstrated significant association between IDDM and a VNTR in the 5{prime} flanking region of the insulin (INS) gene. Paradoxically, all attempts to demonstrate linkage of IDDM to this VNTR have failed. Lack of linkage has been attributed to insufficient marker locus information, genetic heterogeneity, or high frequency of the IDDM-predisposing allele in the general population. Tyrosine hydroxylase (TH) is located 2.7 kb from INS on the 5` side of the VNTR and shows linkage disequilibrium with INS region loci. We typed a highly polymorphic microsatellite within TH in 176 multiplex families, and performed parametric (lod score) linkage analysis using various intermediate reduced penetrance models for IDDM (including rare and common disease allele frequencies), as well as non-parametric (affected sib pair) linkage analysis. The scores significantly reject linkage for recombination values of .05 or less, excluding the entire 19 kb region containing TH, the 5{prime} VNTR, the INS gene, and IGF2 on the 3{prime} side of INS. Non-parametric linkage analysis also provided no significant evidence for linkage (mean TH allele sharing 52.5%, P=.12). These results have important implications for efforts to locate genes predisposing to complex disorders, strongly suggesting that regions which are significantly excluded by linkage methods may nevertheless contain predisposing genes readily detectable by association methods. We advocate that investigators routinely perform association analyses in addition to linkage analyses.

Calcium Carbonate Phosphate Binding Ion Exchange Filtration and Accelerated Denitrification Improve Public Health Standards and Combat Eutrophication in Aquatic Ecosystems

OpenAIRE

Yanamadala, Vijay

2005-01-01

Cultural eutrophication, the process by which a lake becomes rich in dissolved nutrients as a result of point and nonpoint pollutant sources, is a major cause of the loss of natural lake ecosystems throughout the world. The process occurs naturally in all lakes, but phosphate-rich nutrient runoff from sources such as storm drains and agricultural runoff is a major cause of excess phosphate-induced eutrophication. Especially in Madrona Marsh, one of the last remaining vernal marshes in the gre...

Characterization of waterborne nitrogen emissions for marine eutrophication modelling in life cycle impact assessment at the damage level and global scale

DEFF Research Database (Denmark)

Cosme, Nuno Miguel Dias; Hauschild, Michael Zwicky

2017-01-01

Current life cycle impact assessment (LCIA) methods lack a consistent and globally applicable characterization model relating nitrogen (N, as dissolved inorganic nitrogen, DIN) enrichment of coastal waters to the marine eutrophication impacts at the endpoint level. This paper introduces a method...... to calculate spatially explicit characterization factors (CFs) at endpoint and damage to ecosystems levels, for waterborne nitrogen emissions, reflecting their hypoxia-related marine eutrophication impacts, modelled for 5772 river basins of the world....

Phytoplankton Diversity Effects on Community Biomass and Stability along Nutrient Gradients in a Eutrophic Lake

Directory of Open Access Journals (Sweden)

Wang Tian

2017-01-01

Full Text Available The relationship between biodiversity and ecosystem functioning is a central issue in ecology, but how this relationship is affected by nutrient stress is still unknown. In this study, we analyzed the phytoplankton diversity effects on community biomass and stability along nutrient gradients in an artificial eutrophic lake. Four nutrient gradients, varying from slightly eutrophic to highly eutrophic states, were designed by adjusting the amount of polluted water that flowed into the lake. Mean phytoplankton biomass, species richness, and Shannon diversity index all showed significant differences among the four nutrient gradients. Phytoplankton community biomass was correlated with diversity (both species richness and Shannon diversity index, varying from positive to negative along the nutrient gradients. The influence of phytoplankton species richness on resource use efficiency (RUE also changed from positive to negative along the nutrient gradients. However, the influence of phytoplankton Shannon diversity on RUE was not significant. Both phytoplankton species richness and Shannon diversity had a negative influence on community turnover (measured as community dissimilarity, i.e., a positive diversity–stability relationship. Furthermore, phytoplankton spatial stability decreased along the nutrient gradients in the lake. With increasing nutrient concentrations, the variability (standard deviation of phytoplankton community biomass increased more rapidly than the average total biomass. Results in this study will be helpful in understanding the phytoplankton diversity effects on ecosystem functioning and how these effects are influenced by nutrient conditions in aquatic ecosystems.

Enhanced effects of biotic interactions on predicting multispecies spatial distribution of submerged macrophytes after eutrophication.

Science.gov (United States)

Song, Kun; Cui, Yichong; Zhang, Xijin; Pan, Yingji; Xu, Junli; Xu, Kaiqin; Da, Liangjun

2017-10-01

Water eutrophication creates unfavorable environmental conditions for submerged macrophytes. In these situations, biotic interactions may be particularly important for explaining and predicting the submerged macrophytes occurrence. Here, we evaluate the roles of biotic interactions in predicting spatial occurrence of submerged macrophytes in 1959 and 2009 for Dianshan Lake in eastern China, which became eutrophic since the 1980s. For the four common species occurred in 1959 and 2009, null species distribution models based on abiotic variables and full models based on both abiotic and biotic variables were developed using generalized linear model (GLM) and boosted regression trees (BRT) to determine whether the biotic variables improved the model performance. Hierarchical Bayesian-based joint species distribution models capable of detecting paired biotic interactions were established for each species in both periods to evaluate the changes in the biotic interactions. In most of the GLM and BRT models, the full models showed better performance than the null models in predicting the species presence/absence, and the relative importance of the biotic variables in the full models increased from less than 50% in 1959 to more than 50% in 2009 for each species. Moreover, co-occurrence correlation of each paired species interaction was higher in 2009 than that in 1959. The findings suggest biotic interactions that tend to be positive play more important roles in the spatial distribution of multispecies assemblages of macrophytes and should be included in prediction models to improve prediction accuracy when forecasting macrophytes' distribution under eutrophication stress.

Detection of QTL for Carcass Quality on Chromosome 6 by Exploiting Linkage and Linkage Disequilibrium in Hanwoo

Directory of Open Access Journals (Sweden)

J.-H. Lee

2012-01-01

Full Text Available The purpose of this study was to improve mapping power and resolution for the QTL influencing carcass quality in Hanwoo, which was previously detected on the bovine chromosome (BTA 6. A sample of 427 steers were chosen, which were the progeny from 45 Korean proven sires in the Hanwoo Improvement Center, Seosan, Korea. The samples were genotyped with the set of 2,535 SNPs on BTA6 that were imbedded in the Illumina bovine 50 k chip. A linkage disequilibrium variance component mapping (LDVCM method, which exploited both linkage between sires and their steers and population-wide linkage disequilibrium, was applied to detect QTL for four carcass quality traits. Fifteen QTL were detected at 0.1% comparison-wise level, for which five, three, five, and two QTL were associated with carcass weight (CWT, backfat thickness (BFT, longissimus dorsi muscle area (LMA, and marbling score (Marb, respectively. The number of QTL was greater compared with our previous results, in which twelve QTL for carcass quality were detected on the BTA6 in the same population by applying other linkage disequilibrium mapping approaches. One QTL for LMA was detected on the distal region (110,285,672 to 110,633,096 bp with the most significant evidence for linkage (p<10−5. Another QTL that was detected on the proximal region (33,596,515 to 33,897,434 bp was pleiotrophic, i.e. influencing CWT, BFT, and LMA. Our results suggest that the LDVCM is a good alternative method for QTL fine-mapping in detection and characterization of QTL.

A general model for likelihood computations of genetic marker data accounting for linkage, linkage disequilibrium, and mutations.

Science.gov (United States)

Kling, Daniel; Tillmar, Andreas; Egeland, Thore; Mostad, Petter

2015-09-01

Several applications necessitate an unbiased determination of relatedness, be it in linkage or association studies or in a forensic setting. An appropriate model to compute the joint probability of some genetic data for a set of persons given some hypothesis about the pedigree structure is then required. The increasing number of markers available through high-density SNP microarray typing and NGS technologies intensifies the demand, where using a large number of markers may lead to biased results due to strong dependencies between closely located loci, both within pedigrees (linkage) and in the population (allelic association or linkage disequilibrium (LD)). We present a new general model, based on a Markov chain for inheritance patterns and another Markov chain for founder allele patterns, the latter allowing us to account for LD. We also demonstrate a specific implementation for X chromosomal markers that allows for computation of likelihoods based on hypotheses of alleged relationships and genetic marker data. The algorithm can simultaneously account for linkage, LD, and mutations. We demonstrate its feasibility using simulated examples. The algorithm is implemented in the software FamLinkX, providing a user-friendly GUI for Windows systems (FamLinkX, as well as further usage instructions, is freely available at www.famlink.se ). Our software provides the necessary means to solve cases where no previous implementation exists. In addition, the software has the possibility to perform simulations in order to further study the impact of linkage and LD on computed likelihoods for an arbitrary set of markers.

Mapping of yield, yield stability, yield adaptability and other traits in barley using linkage disequilibrium mapping and linkage analysis

NARCIS (Netherlands)

Kraakman, A.T.W.

2005-01-01

Plants is mostly done through linkage analysis. A segregating mapping population Identification and mappping of Quantitative Trait Loci (QTLs) in is created from a bi-parental cross and linkages between trait values and mapped markers reveal the positions ofQTLs. In

Two-locus linkage analysis in multiple sclerosis (MS)

Energy Technology Data Exchange (ETDEWEB)

Tienari, P.J. (National Public Health Institute, Helsinki (Finland) Univ. of Helsinki (Finland)); Terwilliger, J.D.; Ott, J. (Columbia Univ., New York (United States)); Palo, J. (Univ. of Helsinki (Finland)); Peltonen, L. (National Public Health Institute, Helsinki (Finland))

1994-01-15

One of the major challenges in genetic linkage analyses is the study of complex diseases. The authors demonstrate here the use of two-locus linkage analysis in multiple sclerosis (MS), a multifactorial disease with a complex mode of inheritance. In a set of Finnish multiplex families, they have previously found evidence for linkage between MS susceptibility and two independent loci, the myelin basic protein gene (MBP) on chromosome 18 and the HLA complex on chromosome 6. This set of families provides a unique opportunity to perform linkage analysis conditional on two loci contributing to the disease. In the two-trait-locus/two-marker-locus analysis, the presence of another disease locus is parametrized and the analysis more appropriately treats information from the unaffected family member than single-disease-locus analysis. As exemplified here in MS, the two-locus analysis can be a powerful method for investigating susceptibility loci in complex traits, best suited for analysis of specific candidate genes, or for situations in which preliminary evidence for linkage already exists or is suggested. 41 refs., 6 tabs.

Interactions between fishes and the structure of fish communities in Dutch shallow, eutrophic lakes

NARCIS (Netherlands)

Lammens, E.

1986-01-01

This thesis describes the structure of fish communities in Tjeukemeer (21 km ²) and some other surrounding very eutrophic lakes and emphasizes the interactions of the fishes with each other and their food organisms (predation and (exploitative) competition). It is a compilation of seven

Quantifying the impact of septic tank systems on eutrophication risk in rural headwaters.

Science.gov (United States)

Withers, P J A; Jarvie, H P; Stoate, C

2011-04-01

Septic tank systems (STS) are a potential source of nutrient emissions to surface waters but few data exist in the UK to quantify their significance for eutrophication. We monitored the impact of STS on nutrient concentrations in a stream network around a typical English village over a 1-year period. Septic tank effluent discharging via a pipe directly into one stream was highly concentrated in soluble N (8-63mgL(-1)) and P (septic tank systems. The very high concentrations, intercorrelation and dilution patterns of SRP, NH(4)-N and the effluent markers Na and B suggested that soakaways in the heavy clay catchment soils were not retaining and treating the septic tank effluents efficiently, with profound implications for stream biodiversity. Water companies, water regulators and rural communities therefore need to be made more aware of the potential impacts of STS on water quality so that their management can be optimised to reduce the risk of potential eutrophication and toxicity to aquatic ecosystems during summer low flow periods. Copyright © 2011 Elsevier Ltd. All rights reserved.

Green synthesis of Fe nanoparticles using eucalyptus leaf extracts for treatment of eutrophic wastewater

International Nuclear Information System (INIS)

Wang, Ting; Jin, Xiaoying; Chen, Zuliang; Megharaj, Mallavarapu; Naidu, Ravendra

2014-01-01

Iron nanoparticles were firstly synthesized through a one-step room-temperature biosynthetic route using eucalyptus leaf extracts (EL-Fe NPs). Scanning electron microscopy (SEM) and X-ray energy-dispersive spectrometer (EDS) confirmed the successful synthesis of the spheroidal iron nanoparticles. Furthermore, X-ray diffraction (XRD) and Fourier Transform Infrared spectrometer (FTIR) indicated that some polyphenols are bound to the surfaces of EL-Fe NPs as a capping/stabilizing agent. Reactivity of EL-Fe NPs was evaluated for the treatment of swine wastewater and results indicated that 71.7% of total N and 84.5% of COD were removed, respectively. This demonstrated the tremendous potential of EL-Fe NPs for in situ remediation of eutrophic wastewater. - Highlights: •Fe NPs were firstly synthesized through a one-step using eucalyptus leaf extracts. •Fe NPs was evaluated by remediating swine wastewater. •71.7% of total N and 84.5% of COD was removed. •Fe NPs for in situ remediation of eutrophic wastewater

Green synthesis of Fe nanoparticles using eucalyptus leaf extracts for treatment of eutrophic wastewater

Energy Technology Data Exchange (ETDEWEB)

Wang, Ting; Jin, Xiaoying [School of Environmental Science and Engineering, Fujian Normal University, Fuzhou 350007, Fujian (China); Chen, Zuliang, E-mail: Zuliang.chen@unisa.edu.au [School of Environmental Science and Engineering, Fujian Normal University, Fuzhou 350007, Fujian (China); Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SA 5095 (Australia); Cooperative Research Centre for Contamination Assessment and Remediation of Environments, Mawson Lakes, SA 5095 (Australia); Megharaj, Mallavarapu; Naidu, Ravendra [Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SA 5095 (Australia); Cooperative Research Centre for Contamination Assessment and Remediation of Environments, Mawson Lakes, SA 5095 (Australia)

2014-01-01

Iron nanoparticles were firstly synthesized through a one-step room-temperature biosynthetic route using eucalyptus leaf extracts (EL-Fe NPs). Scanning electron microscopy (SEM) and X-ray energy-dispersive spectrometer (EDS) confirmed the successful synthesis of the spheroidal iron nanoparticles. Furthermore, X-ray diffraction (XRD) and Fourier Transform Infrared spectrometer (FTIR) indicated that some polyphenols are bound to the surfaces of EL-Fe NPs as a capping/stabilizing agent. Reactivity of EL-Fe NPs was evaluated for the treatment of swine wastewater and results indicated that 71.7% of total N and 84.5% of COD were removed, respectively. This demonstrated the tremendous potential of EL-Fe NPs for in situ remediation of eutrophic wastewater. - Highlights: •Fe NPs were firstly synthesized through a one-step using eucalyptus leaf extracts. •Fe NPs was evaluated by remediating swine wastewater. •71.7% of total N and 84.5% of COD was removed. •Fe NPs for in situ remediation of eutrophic wastewater.

Using Bureaucratic and Cultural Linkages to Improve Instruction: The Principal's Contribution.

Science.gov (United States)

Firestone, William A.; Wilson, Bruce L.

1985-01-01

Principals can influence teachers and instructional behavior by working through linkage mechanisms within the organizational structure of the school. Two types of linkages are identified: bureaucratic and cultural. Principals have access to linkages of both kinds; using linkages effectively, they can generate a common purpose in their schools. (MD)

The role of benthic macrofauna on nitrogen cycling in eutrophic lake sediment

Energy Technology Data Exchange (ETDEWEB)

Svensson, J M

1998-12-01

This thesis concerns the role of sediment-living macrobenthos in the cycling of nitrogen species and nitrogen transformation in eutrophic freshwater sediments. In my thesis I have, employing {sup 15}N-isotope techniques in laboratory experiments, shown the importance of infaunal chironomid larvae and oligochaetes on denitrification in eutrophic lake sediments. Investigated benthic organisms not only expand the sediment surface with their permanent or non-permanent burrow constructions, they also transport water through the burrows continuously. This behaviour of intermittent water-pumping activity, provides the burrows with oxygen, and in addition, mediates the supply of nitrate to denitrifying zones. The highly dynamic oxygen climate within and narrow oxic zones around burrows, due to their radial geometry, provides a very short diffusion path for nitrate into surrounding anoxic zones. In my studies rates of denitrification were enhanced c. 3 to 6-fold by the influence of chironomids (Chironomus plumosus) and c. 2-fold by the influence of oligochaetes at comparable biomass. The difference in degree of stimulation is explained by species-specific habitat exploitation which could also be observed between different tube-dwelling species of chironomids. Besides chironomid biomass, the degree of enhancement of denitrification by chironomids was dependent on nitrate concentration in the overlying water, and water temperature. Nitrification was also seen to be stimulated by the infaunal macrobenthos but to a lesser degree than denitrification. It is suggested that bioturbated eutrophic sediment, under predominantly oxic bottom water conditions may act more pronouncedly as a sink for inorganic nitrogen relative to non-bioturbated sediment, and that bioturbated sediment above all, may be an important factor contributing to lowered transport of nitrogen to the coast. In order to sustain high nitrogen removal capacity in wetlands, ponds and lakes, it is further suggested

In-Situ Effects of Simulated Overfishing and Eutrophication on Benthic Coral Reef Algae Growth, Succession, and Composition in the Central Red Sea

OpenAIRE

Jessen, Christian; Roder, Cornelia; Villa Lizcano, Javier Felipe; Voolstra, Christian R.; Wild, Christian

2013-01-01

Overfishing and land-derived eutrophication are major local threats to coral reefs and may affect benthic communities, moving them from coral dominated reefs to algal dominated ones. The Central Red Sea is a highly under-investigated area, where healthy coral reefs are contending against intense coastal development. This in-situ study investigated both the independent and combined effects of manipulated inorganic nutrient enrichment (simulation of eutrophication) and herbivore exclosure (simu...

In-situ effects of eutrophication and overfishing on physiology and bacterial diversity of the red sea coral Acropora hemprichii.

KAUST Repository

Jessen, Christian

2013-04-22

Coral reefs of the Central Red Sea display a high degree of endemism, and are increasingly threatened by anthropogenic effects due to intense local coastal development measures. Overfishing and eutrophication are among the most significant local pressures on these reefs, but there is no information available about their potential effects on the associated microbial community. Therefore, we compared holobiont physiology and 16S-based bacterial communities of tissue and mucus of the hard coral Acropora hemprichii after 1 and 16 weeks of in-situ inorganic nutrient enrichment (via fertilizer diffusion) and/or herbivore exclusion (via caging) in an offshore reef of the Central Red Sea. Simulated eutrophication and/or overfishing treatments did not affect coral physiology with respect to coral respiration rates, chlorophyll a content, zooxanthellae abundance, or δ (15)N isotopic signatures. The bacterial community of A. hemprichii was rich and uneven, and diversity increased over time in all treatments. While distinct bacterial species were identified as a consequence of eutrophication, overfishing, or both, two bacterial species that could be classified to the genus Endozoicomonas were consistently abundant and constituted two thirds of bacteria in the coral. Several nitrogen-fixing and denitrifying bacteria were found in the coral specimens that were exposed to experimentally increased nutrients. However, no particular bacterial species was consistently associated with the coral under a given treatment and the single effects of manipulated eutrophication and overfishing could not predict the combined effect. Our data underlines the importance of conducting field studies in a holobiont framework, taking both, physiological and molecular measures into account.

In-situ effects of eutrophication and overfishing on physiology and bacterial diversity of the red sea coral Acropora hemprichii.

Science.gov (United States)

Jessen, Christian; Villa Lizcano, Javier Felipe; Bayer, Till; Roder, Cornelia; Aranda, Manuel; Wild, Christian; Voolstra, Christian R

2013-01-01

Coral reefs of the Central Red Sea display a high degree of endemism, and are increasingly threatened by anthropogenic effects due to intense local coastal development measures. Overfishing and eutrophication are among the most significant local pressures on these reefs, but there is no information available about their potential effects on the associated microbial community. Therefore, we compared holobiont physiology and 16S-based bacterial communities of tissue and mucus of the hard coral Acropora hemprichii after 1 and 16 weeks of in-situ inorganic nutrient enrichment (via fertilizer diffusion) and/or herbivore exclusion (via caging) in an offshore reef of the Central Red Sea. Simulated eutrophication and/or overfishing treatments did not affect coral physiology with respect to coral respiration rates, chlorophyll a content, zooxanthellae abundance, or δ (15)N isotopic signatures. The bacterial community of A. hemprichii was rich and uneven, and diversity increased over time in all treatments. While distinct bacterial species were identified as a consequence of eutrophication, overfishing, or both, two bacterial species that could be classified to the genus Endozoicomonas were consistently abundant and constituted two thirds of bacteria in the coral. Several nitrogen-fixing and denitrifying bacteria were found in the coral specimens that were exposed to experimentally increased nutrients. However, no particular bacterial species was consistently associated with the coral under a given treatment and the single effects of manipulated eutrophication and overfishing could not predict the combined effect. Our data underlines the importance of conducting field studies in a holobiont framework, taking both, physiological and molecular measures into account.

In-situ effects of eutrophication and overfishing on physiology and bacterial diversity of the red sea coral Acropora hemprichii.

Directory of Open Access Journals (Sweden)

Christian Jessen

Full Text Available Coral reefs of the Central Red Sea display a high degree of endemism, and are increasingly threatened by anthropogenic effects due to intense local coastal development measures. Overfishing and eutrophication are among the most significant local pressures on these reefs, but there is no information available about their potential effects on the associated microbial community. Therefore, we compared holobiont physiology and 16S-based bacterial communities of tissue and mucus of the hard coral Acropora hemprichii after 1 and 16 weeks of in-situ inorganic nutrient enrichment (via fertilizer diffusion and/or herbivore exclusion (via caging in an offshore reef of the Central Red Sea. Simulated eutrophication and/or overfishing treatments did not affect coral physiology with respect to coral respiration rates, chlorophyll a content, zooxanthellae abundance, or δ (15N isotopic signatures. The bacterial community of A. hemprichii was rich and uneven, and diversity increased over time in all treatments. While distinct bacterial species were identified as a consequence of eutrophication, overfishing, or both, two bacterial species that could be classified to the genus Endozoicomonas were consistently abundant and constituted two thirds of bacteria in the coral. Several nitrogen-fixing and denitrifying bacteria were found in the coral specimens that were exposed to experimentally increased nutrients. However, no particular bacterial species was consistently associated with the coral under a given treatment and the single effects of manipulated eutrophication and overfishing could not predict the combined effect. Our data underlines the importance of conducting field studies in a holobiont framework, taking both, physiological and molecular measures into account.

Distribution of lod scores in oligogenic linkage analysis.

Science.gov (United States)

Williams, J T; North, K E; Martin, L J; Comuzzie, A G; Göring, H H; Blangero, J

2001-01-01

In variance component oligogenic linkage analysis it can happen that the residual additive genetic variance bounds to zero when estimating the effect of the ith quantitative trait locus. Using quantitative trait Q1 from the Genetic Analysis Workshop 12 simulated general population data, we compare the observed lod scores from oligogenic linkage analysis with the empirical lod score distribution under a null model of no linkage. We find that zero residual additive genetic variance in the null model alters the usual distribution of the likelihood-ratio statistic.

Data Linkage: A powerful research tool with potential problems

Directory of Open Access Journals (Sweden)

Scott Ian

2010-12-01

Full Text Available Abstract Background Policy makers, clinicians and researchers are demonstrating increasing interest in using data linked from multiple sources to support measurement of clinical performance and patient health outcomes. However, the utility of data linkage may be compromised by sub-optimal or incomplete linkage, leading to systematic bias. In this study, we synthesize the evidence identifying participant or population characteristics that can influence the validity and completeness of data linkage and may be associated with systematic bias in reported outcomes. Methods A narrative review, using structured search methods was undertaken. Key words "data linkage" and Mesh term "medical record linkage" were applied to Medline, EMBASE and CINAHL databases between 1991 and 2007. Abstract inclusion criteria were; the article attempted an empirical evaluation of methodological issues relating to data linkage and reported on patient characteristics, the study design included analysis of matched versus unmatched records, and the report was in English. Included articles were grouped thematically according to patient characteristics that were compared between matched and unmatched records. Results The search identified 1810 articles of which 33 (1.8% met inclusion criteria. There was marked heterogeneity in study methods and factors investigated. Characteristics that were unevenly distributed among matched and unmatched records were; age (72% of studies, sex (50% of studies, race (64% of studies, geographical/hospital site (93% of studies, socio-economic status (82% of studies and health status (72% of studies. Conclusion A number of relevant patient or population factors may be associated with incomplete data linkage resulting in systematic bias in reported clinical outcomes. Readers should consider these factors in interpreting the reported results of data linkage studies.

Pelagic and benthic nutrient regeneration processes in mussel cultures (Mytilus edulis) in a eutrophic coastal area (Skive Fjord, Denmark)

DEFF Research Database (Denmark)

Holmer, Marianne; Thorsen, Sandra Walløe; Carlsson, Marita Sundstein

2015-01-01

Long-line mussel farming has been proposed as a mitigation tool in eutrophic coastal areas as nutrients are removed from the ecosystem upon harvest of the crops and transferred back to land. Further mussels filter the water and thereby increase water transparency and promote benthic plant growth...... of this study was to explore the environmental interactions of a long-line mussel farm located in a eutrophic coastal area (Skive Fjord, Denmark) by studying the nutrient cycling in the water column and sediments and assessing their contribution to the nutrient dynamics and oxygen conditions in the fjord...

Genome-wide linkage scan for colorectal cancer susceptibility genes supports linkage to chromosome 3q

Directory of Open Access Journals (Sweden)

Velculescu Victor E

2008-04-01

Full Text Available Abstract Background Colorectal cancer is one of the most common causes of cancer-related mortality. The disease is clinically and genetically heterogeneous though a strong hereditary component has been identified. However, only a small proportion of the inherited susceptibility can be ascribed to dominant syndromes, such as Hereditary Non-Polyposis Colorectal Cancer (HNPCC or Familial Adenomatous Polyposis (FAP. In an attempt to identify novel colorectal cancer predisposing genes, we have performed a genome-wide linkage analysis in 30 Swedish non-FAP/non-HNPCC families with a strong family history of colorectal cancer. Methods Statistical analysis was performed using multipoint parametric and nonparametric linkage. Results Parametric analysis under the assumption of locus homogeneity excluded any common susceptibility regions harbouring a predisposing gene for colorectal cancer. However, several loci on chromosomes 2q, 3q, 6q, and 7q with suggestive linkage were detected in the parametric analysis under the assumption of locus heterogeneity as well as in the nonparametric analysis. Among these loci, the locus on chromosome 3q21.1-q26.2 was the most consistent finding providing positive results in both parametric and nonparametric analyses Heterogeneity LOD score (HLOD = 1.90, alpha = 0.45, Non-Parametric LOD score (NPL = 2.1. Conclusion The strongest evidence of linkage was seen for the region on chromosome 3. Interestingly, the same region has recently been reported as the most significant finding in a genome-wide analysis performed with SNP arrays; thus our results independently support the finding on chromosome 3q.

Upland Forest Linkages to Seasonal Wetlands: Litter Flux, Processing, and Food Quality

Science.gov (United States)

Brian J. Palik; Darold P. Batzer; Christel Kern

2005-01-01

The flux of materials across ecosystem boundaries has significant effects on recipient systems. Because of edge effects, seasonal wetlands in upland forest are good systems to explore these linkages. The purpose of this study was to examine flux of coarse particulate organic matter as litter fall into seasonal wetlands in Minnesota, and the relationship of this flux to...

An estimating function approach to linkage heterogeneity

Indian Academy of Sciences (India)

Testing linkage heterogeneity between two loci is an important issue in genetics. Currently, there are ... on linkage heterogeneity can help people to better understand complex .... χ2(F − 2) + cχ2 (1), where c is a constant (see Appendix). Here, it can be ..... gin, ancestry, gender, age, etc., for purpose of dividing sub- groups to ...

Bayesian linkage and segregation analysis: factoring the problem.

Science.gov (United States)

Matthysse, S

2000-01-01

Complex segregation analysis and linkage methods are mathematical techniques for the genetic dissection of complex diseases. They are used to delineate complex modes of familial transmission and to localize putative disease susceptibility loci to specific chromosomal locations. The computational problem of Bayesian linkage and segregation analysis is one of integration in high-dimensional spaces. In this paper, three available techniques for Bayesian linkage and segregation analysis are discussed: Markov Chain Monte Carlo (MCMC), importance sampling, and exact calculation. The contribution of each to the overall integration will be explicitly discussed.

Mobile assemblies of Bennett linkages from four-crease origami patterns

Science.gov (United States)

Zhang, Xiao; Chen, Yan

2018-02-01

This paper deals with constructing mobile assemblies of Bennett linkages inspired by four-crease origami patterns. A transition technique has been proposed by taking the thick-panel form of an origami pattern as an intermediate bridge. A zero-thickness rigid origami pattern and its thick-panel form share the same sector angles and folding behaviours, while the thick-panel origami and the mobile assembly of linkages are kinematically equivalent with differences only in link profiles. Applying this transition technique to typical four-crease origami patterns, we have found that the Miura-ori and graded Miura-ori patterns lead to assemblies of Bennett linkages with identical link lengths. The supplementary-type origami patterns with different mountain-valley crease assignments correspond to different types of Bennett linkage assemblies with negative link lengths. And the identical linkage-type origami pattern generates a new mobile assembly. Hence, the transition technique offers a novel approach to constructing mobile assemblies of spatial linkages from origami patterns.

Dimensional threshold for fracture linkage and hooking

Science.gov (United States)

Lamarche, Juliette; Chabani, Arezki; Gauthier, Bertrand D. M.

2018-03-01

Fracture connectivity in rocks depends on spatial properties of the pattern including length, abundance and orientation. When fractures form a single-strike set, they hardly cross-cut each other and the connectivity is limited. Linkage probability increases with increasing fracture abundance and length as small fractures connect to each other to form longer ones. A process for parallel fracture linkage is the "hooking", where two converging fracture tips mutually deviate and then converge to connect due to the interaction of their crack-tip stresses. Quantifying the processes and conditions for fracture linkage in single-strike fracture sets is crucial to better predicting fluid flow in Naturally Fractured Reservoirs. For 1734 fractures in Permian shales of the Lodève Basin, SE France, we measured geometrical parameters in 2D, characterizing three stages of the hooking process: underlapping, overlapping and linkage. We deciphered the threshold values, shape ratios and limiting conditions to switch from one stage to another one. The hook set up depends on the spacing (S) and fracture length (Lh) with the relation S ≈ 0.15 Lh. Once the hooking is initiated, with the fracture deviation length (L) L ≈ 0.4 Lh, the fractures reaches the linkage stage only when the spacing is reduced to S ≈ 0.02 Lh and the convergence (C) is < 0.1 L. These conditions apply to multi-scale fractures with a shape ratio L/S = 10 and for fracture curvature of 10°-20°.

Possible future effects of large-scale algae cultivation for biofuels on coastal eutrophication in Europe

NARCIS (Netherlands)

Blaas, H.; Kroeze, C.

2014-01-01

Biodiesel is increasingly considered as an alternative for fossil diesel. Biodiesel can be produced from rapeseed, palm, sunflower, soybean and algae. In this study, the consequences of large-scale production of biodiesel from micro-algae for eutrophication in four large European seas are analysed.

Mapping of yield, yield stability, yield adaptability and other traits in barley using linkage disequilibrium mapping and linkage analysis

OpenAIRE

Kraakman, A.T.W.

2005-01-01

Plants is mostly done through linkage analysis. A segregating mapping population Identification and mappping of Quantitative Trait Loci (QTLs) in is created from a bi-parental cross and linkages between trait values and mapped markers reveal the positions ofQTLs. Inthisstudyweexploredlinkagedisequilibrium(LD)mappingof traits in a set of modernbarleycultivars. LDbetweenmolecularmarkerswasfoundup to a distance of 10 centimorgan,whichislargecomparedtootherspecies.Thelarge distancemightbeinducedb...

Record linkage for pharmacoepidemiological studies in cancer patients.

Science.gov (United States)

Herk-Sukel, Myrthe P P van; Lemmens, Valery E P P; Poll-Franse, Lonneke V van de; Herings, Ron M C; Coebergh, Jan Willem W

2012-01-01

An increasing need has developed for the post-approval surveillance of (new) anti-cancer drugs by means of pharmacoepidemiology and outcomes research in the area of oncology. To create an overview that makes researchers aware of the available database linkages in Northern America and Europe which facilitate pharmacoepidemiology and outcomes research in cancer patients. In addition to our own database, i.e. the Eindhoven Cancer Registry (ECR) linked to the PHARMO Record Linkage System, we considered database linkages between a population-based cancer registry and an administrative healthcare database that at least contains information on drug use and offers a longitudinal perspective on healthcare utilization. Eligible database linkages were limited to those that had been used in multiple published articles in English language included in Pubmed. The HMO Cancer Research Network (CRN) in the US was excluded from this review, as an overview of the linked databases participating in the CRN is already provided elsewhere. Researchers who had worked with the data resources included in our review were contacted for additional information and verification of the data presented in the overview. The following database linkages were included: the Surveillance, Epidemiology, and End-Results-Medicare; cancer registry data linked to Medicaid; Canadian cancer registries linked to population-based drug databases; the Scottish cancer registry linked to the Tayside drug dispensing data; linked databases in the Nordic Countries of Europe: Norway, Sweden, Finland and Denmark; and the ECR-PHARMO linkage in the Netherlands. Descriptives of the included database linkages comprise population size, generalizability of the population, year of first data availability, contents of the cancer registry, contents of the administrative healthcare database, the possibility to select a cancer-free control cohort, and linkage to other healthcare databases. The linked databases offer a longitudinal

A guide to evaluating linkage quality for the analysis of linked data.

Science.gov (United States)

Harron, Katie L; Doidge, James C; Knight, Hannah E; Gilbert, Ruth E; Goldstein, Harvey; Cromwell, David A; van der Meulen, Jan H

2017-10-01

Linked datasets are an important resource for epidemiological and clinical studies, but linkage error can lead to biased results. For data security reasons, linkage of personal identifiers is often performed by a third party, making it difficult for researchers to assess the quality of the linked dataset in the context of specific research questions. This is compounded by a lack of guidance on how to determine the potential impact of linkage error. We describe how linkage quality can be evaluated and provide widely applicable guidance for both data providers and researchers. Using an illustrative example of a linked dataset of maternal and baby hospital records, we demonstrate three approaches for evaluating linkage quality: applying the linkage algorithm to a subset of gold standard data to quantify linkage error; comparing characteristics of linked and unlinked data to identify potential sources of bias; and evaluating the sensitivity of results to changes in the linkage procedure. These approaches can inform our understanding of the potential impact of linkage error and provide an opportunity to select the most appropriate linkage procedure for a specific analysis. Evaluating linkage quality in this way will improve the quality and transparency of epidemiological and clinical research using linked data. © The Author 2017. Published by Oxford University Press on behalf of the International Epidemiological Association.

Spread of Alsidium corallinum C. Ag. in a Tyrrhenian eutrophic lagoon dominated by opportunistic macroalgae

International Nuclear Information System (INIS)

Lenzi, Mauro; Gennaro, Paola; Renzi, Monia; Persia, Emma; Porrello, Salvatore

2012-01-01

Highlights: ► In 2007, Alsidium corallinum bloomed in Orbetello lagoon replacing other macroalgae. ► The main cause hypothesized was a transient low eutrophic level of the ecosystem. ► The results showed unusually low dissolved nitrogen in 2007. ► Dissolved N:P atomic ratio was much lower in 2007 than in the past and 2008. ► The observations suggest that the cycle of sediment OM determines vegetation cycles. - Abstract: In 2007, the Rhodophyceae Alsidium corallinum C. Ag., a marine taxon, bloomed in the eutrophic lagoon of Orbetello (Tuscany, Italy) for the first time, becoming the dominant species in spring and summer. In November, its biomass collapsed. The hypothesis examined in this study is that the bloom expressed a relatively low eutrophic level of the ecosystem after intense disposal of accumulated sedimentary organic matter (OM) by dystrophic processes in the two years preceding the bloom. To verify the hypothesis, we compared water physical–chemical variables, sediment redox (Eh) and OM, and standing crops of macroalgae and seagrass from the database of routine monitoring between 2005 and 2008. We also used dissolved nutrient data obtained in 2007 and 2008, as well as data on chlorophyll and total suspended matter in the water column during the microalgal bloom of 2007, and C, N and P content in thalli of the Chlorophycea Chaetomorpha linum and the Rhodophyceae Gracilariopsis longissima and A. corallinum obtained in 2007. In 2007, unusually low values of dissolved inorganic nitrogen (DIN) were recorded. Combined with stable values of soluble reactive phosphorus (SRPs), low DIN led to a reduction of about one order of magnitude in the DIN:SRP atomic ratio with respect to the past and to 2008. G. longissima accumulated C, N and P more than the other species and A. corallinum proved to be less demanding. Sediment OM was lower in the autumn of years characterized by dystrophy, confirming that summer dystrophic events coincided with maximum energy

The eutrophication process and its impact on quality groundwater: theorists bases. La eutrofizacion y su incidencia en la calidad de las aguas subterraneas: bases teoricas

Energy Technology Data Exchange (ETDEWEB)

Gomez Martos, M.; Buyo Hernandez, F.

1993-01-01

This first part of the paper deals with the eutrophication process principles, origin and mechanisms, impact on water resources, management and treatment methods and technology, modeling of process behaviour and lastly, national and international legal policy and measures on eutrophication focused to prevent its impact on water environment and to preserve water quality. 30 refs.

Determinants of the microbial community structure of eutrophic, hyporheic river sediments polluted with chlorinated aliphatic hydrocarbons

NARCIS (Netherlands)

Hamonts, K.; Ryngaert, A.; Smidt, H.; Springael, D.; Dejonghe, W.

2014-01-01

Chlorinated aliphatic hydrocarbons (CAHs) often discharge into rivers as contaminated groundwater baseflow. As biotransformation of CAHs in the impacted river sediments might be an effective remediation strategy, we investigated the determinants of the microbial community structure of eutrophic,

The research on Nelumbonucifera for eutrophication control in Wuliangsuhailake Inner Mongolia,China

Science.gov (United States)

Li, Xing; Xu, Xiaoqing; Gou, Mangmang

2018-02-01

In order to study the effect on Nelumbonucifera (common name:lotus) for eutrophication control in Wuliangsuhai lake inner Mongolia, an enclosure of 2000m2was established in the southeast of Wuliangsuhailake. In the paper, the changes on water quality and phytoplankton abundance were monitored before planting lotus, after. Purpose of the study is to investigate the influence of lotus on improving water quality, restoration of water environment, and so on. The results were shown below. Firstly, Plantinglotus was significant for removal of total nitrogen and total phosphorus in water. Total nitrogen removal rate was more than 25%.Total phosphorus removal rate was more than 30%.Secondly, dissolved oxygen concentrations in August increased by 39.31percent.The Simultaneously, compared with the control (in April), the pH value was 8.0 in August(the flowering period) and declined by 10.11 percent. In this salinity, lotus had a strong salt tolerance and growed normally. Lastly, the biomass of phytoplankton was inhibited after planting lotus, especially for the inhibition of green algae growth. Studies on water bodies restoration under planting lotus in Wuliangsuhai lake have not been reported.Therefore, planting lotus will provide a new idea and theoretical reference for improving the eutrophication of Wuliangsuhailake.

Mapping eutrophication risk from climate change: Future phosphorus concentrations in English rivers.

Science.gov (United States)

Charlton, Matthew B; Bowes, Michael J; Hutchins, Michael G; Orr, Harriet G; Soley, Rob; Davison, Paul

2018-02-01

Climate change is expected to increase eutrophication risk in rivers yet few studies identify the timescale or spatial extent of such impacts. Phosphorus concentration, considered the primary driver of eutrophication risk in English rivers, may increase through reduced dilution particularly if river flows are lower in summer. Detailed models can indicate change in catchment phosphorus concentrations but targeted support for mitigation measures requires a national scale evaluation of risk. In this study, a load apportionment model is used to describe the current relationship between flow and total reactive phosphorus (TRP) at 115 river sites across England. These relationships are used to estimate TRP concentrations for the 2050s under 11 climate change driven scenarios of future river flows and under scenarios of both current and higher levels of sewage treatment. National maps of change indicate a small but inconsistent increase in annual average TRP concentrations with a greater change in summer. Reducing the TRP concentration of final sewage effluent to 0.5mg/L P for all upstream sewage treatment works was inadequate to meet existing P standards required through the EU Water Framework Directive, indicating that more needs to be done, including efforts to reduce diffuse pollution. Copyright © 2017 Elsevier B.V. All rights reserved.

Magnitude, spatial scale and optimization of ecosystem services from a nutrient extraction mussel farm in the eutrophic Skive Fjord, Denmark

DEFF Research Database (Denmark)

Nielsen, Pernille; Cranford, P. J.; Maar, M.

2016-01-01

Suspended mussel aquaculture has been proposed as a possible mechanism by which to remove excess nutrients from eutrophic marine areas. In this study, seasonal mussel growth and water clarification (through seston and phytoplankton depletion) were studied at a commercial-scale nutrient extractive...... mussel farm in a highly eu - trophic Danish fjord. Spatial variations in mussel biomass were examined throughout the year and no significant differences were detected within the farm. Food depletion by mussels was examined at spatial scales ranging from individuals to the entire farm and surrounding area....... Phytoplankton depletion on the scale of individual mussel loops, determined using the siphon mimic approach, indicated between 27 and 44% depletion of chlorophyll a (chl a). Farm-scale depletion was detected and visualized based on intensive 3D spatial surveys of the distribution of chl a and total suspended...

Quantifying sources of bias in longitudinal data linkage studies of child abuse and neglect: measuring impact of outcome specification, linkage error, and partial cohort follow-up.

Science.gov (United States)

Parrish, Jared W; Shanahan, Meghan E; Schnitzer, Patricia G; Lanier, Paul; Daniels, Julie L; Marshall, Stephen W

2017-12-01

Health informatics projects combining statewide birth populations with child welfare records have emerged as a valuable approach to conducting longitudinal research of child maltreatment. The potential bias resulting from linkage misspecification, partial cohort follow-up, and outcome misclassification in these studies has been largely unexplored. This study integrated epidemiological survey and novel administrative data sources to establish the Alaska Longitudinal Child Abuse and Neglect Linkage (ALCANLink) project. Using these data we evaluated and quantified the impact of non-linkage misspecification and single source maltreatment ascertainment use on reported maltreatment risk and effect estimates. The ALCANLink project integrates the 2009-2011 Alaska Pregnancy Risk Assessment Monitoring System (PRAMS) sample with multiple administrative databases through 2014, including one novel administrative source to track out-of-state emigration. For this project we limited our analysis to the 2009 PRAMS sample. We report on the impact of linkage quality, cohort follow-up, and multisource outcome ascertainment on the incidence proportion of reported maltreatment before age 6 and hazard ratios of selected characteristics that are often available in birth cohort linkage studies of maltreatment. Failure to account for out-of-state emigration biased the incidence proportion by 12% (from 28.3% w to 25.2% w ), and the hazard ratio (HR) by as much as 33% for some risk factors. Overly restrictive linkage parameters biased the incidence proportion downwards by 43% and the HR by as much as 27% for some factors. Multi-source linkages, on the other hand, were of little benefit for improving reported maltreatment ascertainment. Using the ALCANLink data which included a novel administrative data source, we were able to observe and quantify bias to both the incidence proportion and HR in a birth cohort linkage study of reported child maltreatment. Failure to account for out

Fifty years of eutrophication and lake restoration reflected in sedimentary carbon and nitrogen isotopes of a small, hardwater lake (south Germany

Directory of Open Access Journals (Sweden)

Emanuel Braig

2013-04-01

Full Text Available This study analyses the response of the carbon and nitrogen isotopic composition of sedimentary organic matter to rapid human-induced eutrophication and meromixis as well as subsequent restoration efforts [in-lake phosphorus (P-Precipitation, P-remediation of the well inflow and multiannual destratification] in a 46-yr sediment core sequence (1963-2009 from Fischkaltersee, a small hard-water lake (S-Germany. In addition, the sediment record was compared with detailed data on water column chemistry during almost (1977-2009 the recorded history of eutrophication and trophic recovery of the named lake. While the onset of eutrophication resulted in an abrupt positive excursion (+2.4‰, the overall reaction of δ13CSOM to ongoing eutrophication and meromixis as well as to permanent hypolimnion aeration and trophic recovery is a continous negative trend (-3.7‰ with the most depleted signatures (-38.8‰ present in the youngest part of the core. This negative trend was not influenced by multiannual hypolimnion aeration, which although oxygenating bottom waters (>2 mg O2 L–1, did not reverse the increasing anoxis in the sediment, as is indicated by an declining Mn/Fe ratio. Hence, we conclude that in Fischkaltersee δ13CSOM was controlled by photoautotrophic input only during an early phase in the eutrophication process. The signal of intensifying microbially mediated carbon cycling processes in the sediment, i.e. methanogenesis and methanotrophy, was superimposed on the primary productivity signal by crossing a certain TP threshold (approx. TP=0.04 mg L–1. Sedimentary δ15N values exhibit an overall increase (+3.4‰ in reaction to the eutrophication process, while trophic recovery produces a continous decrease in the signal (-2.7‰. Linear correlation of δ15N to nitrate utilisation in the epilimnion, however, is rather weak (R2=0.33. Comparison between sediment δ15N values and water column data reveals that two negative shifts in the

Evaluation of extracellular products and mutagenicity in cyanobacteria cultures separated from a eutrophic reservoir

International Nuclear Information System (INIS)

Huang, W.-J.; Lai, C.-H.; Cheng, Y.-L.

2007-01-01

The algal extracellular products (ECPs) in three cultures of cyanobacteria species (Anabaena, Microcystis, and Oscillatoria) dominating the eutrophic reservoir populations and their toxins have been investigated in the present work. Using gas chromatography coupled with high-resolution electron-impact mass spectrometry (GC/EI-MS) and high performance anion-exchange chromatography (HPAEC) techniques, more than 20 compounds were found in the algal culture (including cells and filtrates) extracts. The main identified ECPs were classified to polysaccharides, hydrocarbons, and aldehydes. Odor causing substances such as trans-1,10-dimethyl-trans-9-decalol (geosmin) and 2-methylisoborneol (2-MIB)were also found in the algal cultures. The potential mutagenicity of the algal suspensions was also studied with the Ames test. The organic extracts of the algal suspension from the axenic cultures were mutagenicity in TA98 without S9 mix and in TA100 with and without S9 mix. The results indicate that the ECPs of three algae species dominating the eutrophic reservoir were mutagenic clearly in the bacterial test

Optical Changes in a Eutrophic Estuary During Reduced Nutrient Loadings

DEFF Research Database (Denmark)

Pedersen, Troels Møller; Sand-Jensen, Kaj; Markager, Stiig

2014-01-01

Loss of water clarity is one of the consequences of coastal eutrophication. Efforts have therefore been made to reduce external nutrient loadings of coastal waters. This paper documents improvements to water clarity between 1985 and 2008–2009 at four stations in the microtidal estuary Roskilde...... to 74 % in 1985 to 78 to 85 % in 2008–2009. Overall, efforts to reduce nutrient loading and improve water clarity appeared to have had a larger impact on POM* than on Chl a and colored dissolved organic matter concentrations in the estuary, which can account for the decrease in the scatter...

Dynamics of particulate phosphorus in a shallow eutrophic lake

Energy Technology Data Exchange (ETDEWEB)

Shinohara, Ryuichiro, E-mail: r-shino@nies.go.jp [National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506 (Japan); Imai, Akio; Kohzu, Ayato; Tomioka, Noriko [National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506 (Japan); Furusato, Eiichi [Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama 338-8570 (Japan); Satou, Takayuki; Sano, Tomoharu; Komatsu, Kazuhiro; Miura, Shingo; Shimotori, Koichi [National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506 (Japan)

2016-09-01

We tested the hypothesis that in shallow, eutrophic Lake Kasumigaura, the concentration of particulate phosphorus (PP) is controlled by biogenic P (P in living or dead phytoplankton and bacterial cells), rather than by resuspension of inorganic P in sediment. Increases in wind velocity and turbidity were associated with bottom shear stress exceeding the critical value for the lake (τ{sub c} = 0.15 N m{sup −2}); this increased turbidity was due to sediment resuspension. However, concentrations of PP; HCl-extractable, reactive P in PP (P-rP); and HCl-extractable, non-reactive P in PP (P-nrP) were not correlated with wind velocity (PP vs. wind velocity: r = 0.40, p > 0.05). Rather, the P-nrP concentration accounted for approximately 79% of PP, and the concentrations of PP, P-rP, and P-nrP were correlated with the particulate organic carbon (POC) concentration (POC vs. PP: r = 0.90, p < 0.01; POC vs. P-rP: r = 0.82, p < 0.01; POC vs. P-nrP: r = 0.86, p < 0.01). In our {sup 31}P nuclear magnetic resonance spectroscopy results, mononucleotides accounted for the largest proportion among the detected P compound classes. In addition, concentrations of mononucleotides, orthophosphate, and pyrophosphate were significantly higher in samples with high POC concentrations, whereas the DNA-P concentration was not. These results suggest that biogenic P affects PP concentrations more strongly than does sediment resuspension, and the production of biogenic P creates a pool of mononucleotides, a class of easily degradable P, even in shallow, eutrophic Lake Kasumigaura. - Highlights: • Biogenic P affected the PP concentration more than did sediment resuspension. • PP correlated with particulate organic carbon concentration but not wind velocity. • Mononucleotides accounted for the largest P compound class of organic P in PP.

[Linkage to care among new human immunodeficiency virus diagnoses in Spain].

Science.gov (United States)

Oliva, Jesús; Malo, Carmen; Fernández, Ana; Izquierdo, Ana; Marcos, Henar; Cevallos, Carlos; Castilla, Jesús; García, Rocio; Díez, Mercedes

2014-03-01

To describe linkage to care among new HIV diagnoses in Spain; and to estimate factors associated to linkage to care within three months after diagnosis. The distribution of the time elapsing between the date of HIV diagnosis and the date of first determination of CD4 (considered to be the date of linkage to care) was calculated among new HIV diagnoses in 2010 in the seven Autonomous Regions participating, where data on date of CD4 count was available. Linkage to care was considered «correct» if done within three months after diagnosis. Factors associated to correct linkage to care were estimated using logistic regression. A total of 1769 new HIV diagnoses were included. Of them, 83.1% had evidence of linkage to care within a year, and 75.7% were linked within three months after diagnosis. Being an injectable drug user (IDU) was the only factor inversely associated with linkage to care within 3 months (OR = 0.3; 95% CI: 0.2-0.6). In Spain linkage to care after HIV diagnosis is good, but there is still room for improvement, especially among IDUs. Copyright © 2013 Elsevier España, S.L. y Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

Phase-Division-Based Dynamic Optimization of Linkages for Drawing Servo Presses

Science.gov (United States)

Zhang, Zhi-Gang; Wang, Li-Ping; Cao, Yan-Ke

2017-11-01

Existing linkage-optimization methods are designed for mechanical presses; few can be directly used for servo presses, so development of the servo press is limited. Based on the complementarity of linkage optimization and motion planning, a phase-division-based linkage-optimization model for a drawing servo press is established. Considering the motion-planning principles of a drawing servo press, and taking account of work rating and efficiency, the constraints of the optimization model are constructed. Linkage is optimized in two modes: use of either constant eccentric speed or constant slide speed in the work segments. The performances of optimized linkages are compared with those of a mature linkage SL4-2000A, which is optimized by a traditional method. The results show that the work rating of a drawing servo press equipped with linkages optimized by this new method improved and the root-mean-square torque of the servo motors is reduced by more than 10%. This research provides a promising method for designing energy-saving drawing servo presses with high work ratings.

Transnational linkages and sustainable transitions in emerging countries: Exploring the role of donor interventions in niche development

DEFF Research Database (Denmark)

Hansen, Ulrich Elmer; Nygaard, Ivan

2013-01-01

Recent studies have found that further development of the MLP is needed to conceptualise and empirically assess the role of transnational linkages in niche development. This paper explores the factors that may explain the effect of twenty years of donor interventions as one form of transnational...... linkage in promoting the development of a palm oil biomass waste-to-energy niche in Malaysia. The paper contributes to the existing literature by a conceptual and empirical examination of this research question. With regard to its empirical findings the paper concludes: (i) that advice on energy policy...

Effects of snails, submerged plants and their coexistence on eutrophication in aquatic ecosystems

OpenAIRE

Mo Shuqing; Zhang Xiufeng; Tang Yali; Liu Zhengwen; Kettridge Nicholas

2017-01-01

Eutrophication resulting from nutrient loading to freshwater habitats is a severe problem, leading to degradation of ecosystems, including deterioration of water quality, water clarity and loss of biodiversity. Measures enacted to restore degraded freshwater ecosystems often involve the reintroduction of submerged plants and aquatic animals with beneficial ecological functions. In a mesocosm experiment, three treatments (planting with Vallisneria natans, introduction of the snail Bellamya aer...

Convergence and impoverishment of fen communities in a eutrophicated agricultural landscape of the Czech Republic

Czech Academy of Sciences Publication Activity Database

Navrátilová, Jana; Hájek, M.; Navrátil, J.; Hájková, Petra; Frazier, R. J.

2017-01-01

Roč. 20, č. 2 (2017), s. 225-235 ISSN 1402-2001 R&D Projects: GA ČR GB14-36079G Institutional support: RVO:67985939 Keywords : eutrophication * historical vegetation data * water level fluctuation Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 2.474, year: 2016

Rising CO2 levels will intensify phytoplankton blooms in eutrophic and hypertrophic lakes.

Directory of Open Access Journals (Sweden)

Jolanda M H Verspagen

Full Text Available Harmful algal blooms threaten the water quality of many eutrophic and hypertrophic lakes and cause severe ecological and economic damage worldwide. Dense blooms often deplete the dissolved CO2 concentration and raise pH. Yet, quantitative prediction of the feedbacks between phytoplankton growth, CO2 drawdown and the inorganic carbon chemistry of aquatic ecosystems has received surprisingly little attention. Here, we develop a mathematical model to predict dynamic changes in dissolved inorganic carbon (DIC, pH and alkalinity during phytoplankton bloom development. We tested the model in chemostat experiments with the freshwater cyanobacterium Microcystis aeruginosa at different CO2 levels. The experiments showed that dense blooms sequestered large amounts of atmospheric CO2, not only by their own biomass production but also by inducing a high pH and alkalinity that enhanced the capacity for DIC storage in the system. We used the model to explore how phytoplankton blooms of eutrophic waters will respond to rising CO2 levels. The model predicts that (1 dense phytoplankton blooms in low- and moderately alkaline waters can deplete the dissolved CO2 concentration to limiting levels and raise the pH over a relatively wide range of atmospheric CO2 conditions, (2 rising atmospheric CO2 levels will enhance phytoplankton blooms in low- and moderately alkaline waters with high nutrient loads, and (3 above some threshold, rising atmospheric CO2 will alleviate phytoplankton blooms from carbon limitation, resulting in less intense CO2 depletion and a lesser increase in pH. Sensitivity analysis indicated that the model predictions were qualitatively robust. Quantitatively, the predictions were sensitive to variation in lake depth, DIC input and CO2 gas transfer across the air-water interface, but relatively robust to variation in the carbon uptake mechanisms of phytoplankton. In total, these findings warn that rising CO2 levels may result in a marked

Rising CO2 Levels Will Intensify Phytoplankton Blooms in Eutrophic and Hypertrophic Lakes

Science.gov (United States)

Verspagen, Jolanda M. H.; Van de Waal, Dedmer B.; Finke, Jan F.; Visser, Petra M.; Van Donk, Ellen; Huisman, Jef

2014-01-01

Harmful algal blooms threaten the water quality of many eutrophic and hypertrophic lakes and cause severe ecological and economic damage worldwide. Dense blooms often deplete the dissolved CO2 concentration and raise pH. Yet, quantitative prediction of the feedbacks between phytoplankton growth, CO2 drawdown and the inorganic carbon chemistry of aquatic ecosystems has received surprisingly little attention. Here, we develop a mathematical model to predict dynamic changes in dissolved inorganic carbon (DIC), pH and alkalinity during phytoplankton bloom development. We tested the model in chemostat experiments with the freshwater cyanobacterium Microcystis aeruginosa at different CO2 levels. The experiments showed that dense blooms sequestered large amounts of atmospheric CO2, not only by their own biomass production but also by inducing a high pH and alkalinity that enhanced the capacity for DIC storage in the system. We used the model to explore how phytoplankton blooms of eutrophic waters will respond to rising CO2 levels. The model predicts that (1) dense phytoplankton blooms in low- and moderately alkaline waters can deplete the dissolved CO2 concentration to limiting levels and raise the pH over a relatively wide range of atmospheric CO2 conditions, (2) rising atmospheric CO2 levels will enhance phytoplankton blooms in low- and moderately alkaline waters with high nutrient loads, and (3) above some threshold, rising atmospheric CO2 will alleviate phytoplankton blooms from carbon limitation, resulting in less intense CO2 depletion and a lesser increase in pH. Sensitivity analysis indicated that the model predictions were qualitatively robust. Quantitatively, the predictions were sensitive to variation in lake depth, DIC input and CO2 gas transfer across the air-water interface, but relatively robust to variation in the carbon uptake mechanisms of phytoplankton. In total, these findings warn that rising CO2 levels may result in a marked intensification of

Dynamic linkages among the gold market, US dollar and crude oil market

Science.gov (United States)

Mo, Bin; Nie, He; Jiang, Yonghong

2018-02-01

This paper aims to examine the dynamic linkages among the gold market, US dollar and crude oil market. The analysis also delves more deeply into the effect of the global financial crisis on the short-term relationship. We use fractional cointegration to analyze the long-term memory feature of these volatility processes to investigate whether they are tied through a common long-term equilibrium. The DCC-MGARCH model is employed to investigate the time-varying long-term linkages among these markets. The Krystou-Labys non-linear asymmetric Granger causality method is used to examine the effect of the financial crisis. We find that (i) there is clearly a long-term dependence among these markets; (ii) the dynamic gold-oil relationship is always positive and the oil-dollar relationship is always negative; and (iii) after the crisis, we can observe evidence of a positive non-linear causal relationship from gold to US dollar and US dollar to crude oil, and a negative non-linear causal relationship from US dollar to gold. Investors who want to construct their optimal portfolios and policymakers who aim to make effective macroeconomic policies should take these findings into account.

Biomanipulation with quagga mussels (Dreissena rostriformis bugensis) to control harmful algal blooms in eutrophic urban ponds

NARCIS (Netherlands)

Waajen, Guido W. A. M.; Van Bruggen, Niek C. B.; Pires, L. Miguel Dionisio; Lengkeek, Wouter; Lurling, Miquel

Many urban ponds in The Netherlands and other countries suffer from eutrophication, resulting in harmful algal blooms which are often dominated by cyanobacteria. A sufficient reduction of nutrients, as prerequisite to mitigate cyanobacterial blooms in urban ponds, is not always feasible. Water

Biomanipulation with quagga mussels (Dreissena rostriformis bugensis) to control harmful algal blooms in eutrophic urban ponds

NARCIS (Netherlands)

Waajen, Guido W.A.M.; Bruggen, Van Niek C.B.; Pires, Miguel Dionisio L.; Lengkeek, Wouter; Lurling, Miguel

2016-01-01

Many urban ponds in The Netherlands and other countries suffer from eutrophication, resulting in harmful algal blooms which are often dominated by cyanobacteria. A sufficient reduction of nutrients, as prerequisite to mitigate cyanobacterial blooms in urban ponds, is not always feasible. Water

An Overview of Sediment Organic Matter Records of Human Eutrophication in the Laurentian Great Lakes Region

Energy Technology Data Exchange (ETDEWEB)

Meyers, Philip A. [University of Michigan, Department of Geological Sciences (United States)], E-mail: pameyers@umich.ed

2006-12-15

The isotopic and molecular compositions of organic matter buried in lake sediments provide information that helps to reconstruct past environmental conditions and to assess impacts of humans on local ecosystems. This overview of sedimentary records from the North American Great Lakes region describes examples of applications of organic geochemistry to paleolimnological reconstructions. These lakes experienced a succession of human-induced environmental changes that started after completion of the Erie Canal in 1825. Agricultural deforestation in the mid-nineteenth century released soil nutrients that increased algal productivity and caused an associated increase in algal biomarkers in sediment records. Eutrophication that accompanied magnified delivery of municipal nutrients to the lakes in the 1960s and 1970s created excursions to less negative {delta}{sup 13}C values in sediment organic matter. Increased organic carbon mass accumulation rates mirror the isotopic evidence of eutrophication in the Great Lakes.

Nature–society linkages in the Aral Sea region

Directory of Open Access Journals (Sweden)

Kristopher D. White

2013-01-01

Full Text Available Central Asia's Aral Sea crisis represents a disaster of monumental proportions, a tragedy for both the region's ecology and its human inhabitants. While the human and natural environments had operated in a sustainable co-joined system for millennia, Tsarist Russian expansion into Central Asia, followed by Soviet expansion of both the cotton industry and unsustainable irrigation practices to anchor it spelled doom for the Aral Sea. Today, many of the political and economic stimuli for such misguided practices continue, as do the continued retreat of the Sea and the proliferation of poor human health. The Aral Sea crisis has received ample scholarly attention, though somewhat surprising is a relative dearth of research explicitly investigating the nature, variety, and directionality of nature–society linkages today within the region. The purpose of this paper is to elucidate the contemporary nature–society linkages operating within the Aral Sea region of Central Asia. Historical nexuses will provide necessary background, and the linkages operating currently within the spheres of regional economy, human health, and political considerations will be detailed. Couching the current crisis within the framework of coupled human–environment system contexts reveals a region in which these linkages are largely inextricable. This paper concludes with a call for a reconsideration of the nature-society linkages and a greater emphasis placed on the local region's ecological and social sustainability.

Water quality index and eutrophication indices of Caiabi River, MT

Directory of Open Access Journals (Sweden)

Grasiane Andrietti

2016-03-01

Full Text Available The objective of this study was to evaluate the water quality of the Caiabi River based upon the water quality index (WQI and the trophic state index (TSI, considering seasonal and spatial variations, with the aim of determining the most appropriate monitoring design for this study site. Sampling for water quality monitoring was conducted at five points on the Caiabi River from July 2012 to June 2013. Quality parameters quantified were as follows: pH, temperature, conductivity, dissolved oxygen, total and thermotolerant coliforms, turbidity, Kjeldahl nitrogen, nitrite, nitrate, total phosphorus, biochemical oxygen demand, series of solids, and chlorophyll a. Sampling procedures and analysis followed the methods recommended by the Standard Methods for the Examination of Water and Wastewater. The WQI results showed that the quality of the Caiabi River water is good. TSI results demonstrated the low risk of eutrophication in the Caiabi River, indicating an ultra-oligotrophic lotic environment. Analysis of variance showed that 10 of the 16 monitored quality parameters presented differences of means between the dry and rainy seasons or among the monitored points or in the interaction between seasons and points. These results indicate that two annual sampling collections at two points may be sufficient to describe the water quality behavior in the basin, as long as the conditions of land use are stable.

Romantic Relationship Commitment and Its Linkages with Commitment to Parents and Friends during Adolescence

Science.gov (United States)

De Goede, Irene H. A.; Branje, Susan; van Duin, Jet; VanderValk, Inge E.; Meeus, Wim

2012-01-01

This five-wave longitudinal study examines linkages between adolescents' perceptions of romantic relationship commitment and the development of adolescents' perceptions of commitment to parents and friends. A total of 218 early-to-middle adolescents (39.0 percent boys) and 185 middle-to-late adolescents (30.8 percent boys) participated.…

Young people's views about consenting to data linkage: findings from the PEARL qualitative study.

Science.gov (United States)

Audrey, Suzanne; Brown, Lindsey; Campbell, Rona; Boyd, Andy; Macleod, John

2016-03-21

Electronic administrative data exist in several domains which, if linked, are potentially useful for research. However, benefits from data linkage should be considered alongside risks such as the threat to privacy. Avon Longitudinal Study of Parents and Children (ALSPAC) is a birth cohort study. The Project to Enhance ALSPAC through Record Linkage (PEARL) was established to enrich the ALSPAC resource through linkage between ALSPAC participants and routine sources of health and social data. Qualitative research was incorporated in the PEARL study to examine participants' views about data linkage and inform approaches to information sharing. This paper focusses on issues of consent. Digitally recorded interviews were conducted with 55 participants aged 17-19 years. Terms and processes relating to consent, anonymization and data linkage were explained to interviewees. Scenarios were used to prompt consideration of linking different sources of data, and whether consent should be requested. Interview recordings were fully transcribed. Thematic analysis was undertaken using the Framework approach. Participant views on data linkage appeared to be most influenced by: considerations around the social sensitivity of the research question, and; the possibility of tangible health benefits in the public interest. Some participants appeared unsure about the effectiveness of anonymization, or did not always view effective anonymization as making consent unnecessary. This was related to notions of ownership of personal information and etiquette around asking permission for secondary use. Despite different consent procedures being explained, participants tended to equate consent with 'opt-in' consent through which participants are 'asked' if their data can be used for a specific study. Participants raising similar concerns came to differing conclusions about whether consent was needed. Views changed when presented with different scenarios, and were sometimes inconsistent. Findings

Sediment nitrogen cycling rates and microbial abundance along a submerged vegetation gradient in a eutrophic lake.

Science.gov (United States)

Yao, Lu; Chen, Chengrong; Liu, Guihua; Liu, Wenzhi

2018-03-01

Decline of submerged vegetation is one of the most serious ecological problems in eutrophic lakes worldwide. Although restoration of submerged vegetation is widely assumed to enhance ecological functions (e.g., nitrogen removal) and aquatic biodiversity, the evidence for this assumption is very limited. Here, we investigated the spatio-temporal patterns of sediment potential nitrification, unamended denitrification and N 2 O production rates along a vegetation gradient in the Lake Honghu, where submerged vegetation was largely restored by prohibiting net-pen aquaculture. We also used five functional genes as markers to quantify the abundance of sediment nitrifying and denitrifying microorganisms. Results showed that unvegetated sediments supported greater nitrification rates than rhizosphere sediments of perennial or seasonal vegetation. However, the absence of submerged vegetation had no significant effect on denitrification and N 2 O production rates. Additionally, the abundance of functional microorganisms in sediments was not significantly different among vegetation types. Season had a strong effect on both nitrogen cycling processes and microbial abundances. The highest nitrification rates were observed in September, while the highest denitrification rates occurred in December. The temporal variation of sediment nitrification, denitrification and N 2 O production rates could be due to changes in water quality and sediment properties rather than submerged vegetation and microbial abundances. Our findings highlight that vegetation restoration in eutrophic lakes improves water quality but does not enhance sediment nitrogen removal rates and microbial abundances. Therefore, for reducing the N level in eutrophic lakes, major efforts should be made to control nutrients export from terrestrial ecosystems. Copyright © 2017 Elsevier B.V. All rights reserved.

Intragroup Emotions: Physiological Linkage and Social Presence.

Science.gov (United States)

Järvelä, Simo; Kätsyri, Jari; Ravaja, Niklas; Chanel, Guillaume; Henttonen, Pentti

2016-01-01

We investigated how technologically mediating two different components of emotion-communicative expression and physiological state-to group members affects physiological linkage and self-reported feelings in a small group during video viewing. In different conditions the availability of second screen text chat (communicative expression) and visualization of group level physiological heart rates and their dyadic linkage (physiology) was varied. Within this four person group two participants formed a physically co-located dyad and the other two were individually situated in two separate rooms. We found that text chat always increased heart rate synchrony but HR visualization only with non-co-located dyads. We also found that physiological linkage was strongly connected to self-reported social presence. The results encourage further exploration of the possibilities of sharing group member's physiological components of emotion by technological means to enhance mediated communication and strengthen social presence.

A high-density SNP linkage scan with 142 combined subtype ADHD sib pairs identifies linkage regions on chromosomes 9 and 16.

Science.gov (United States)

Asherson, P; Zhou, K; Anney, R J L; Franke, B; Buitelaar, J; Ebstein, R; Gill, M; Altink, M; Arnold, R; Boer, F; Brookes, K; Buschgens, C; Butler, L; Cambell, D; Chen, W; Christiansen, H; Feldman, L; Fleischman, K; Fliers, E; Howe-Forbes, R; Goldfarb, A; Heise, A; Gabriëls, I; Johansson, L; Lubetzki, I; Marco, R; Medad, S; Minderaa, R; Mulas, F; Müller, U; Mulligan, A; Neale, B; Rijsdijk, F; Rabin, K; Rommelse, N; Sethna, V; Sorohan, J; Uebel, H; Psychogiou, L; Weeks, A; Barrett, R; Xu, X; Banaschewski, T; Sonuga-Barke, E; Eisenberg, J; Manor, I; Miranda, A; Oades, R D; Roeyers, H; Rothenberger, A; Sergeant, J; Steinhausen, H-C; Taylor, E; Thompson, M; Faraone, S V

2008-05-01

As part of the International Multi-centre ADHD Genetics project we completed an affected sibling pair study of 142 narrowly defined Diagnostic and Statistical Manual of Mental Disorders, fourth edition combined type attention deficit hyperactivity disorder (ADHD) proband-sibling pairs. No linkage was observed on the most established ADHD-linked genomic regions of 5p and 17p. We found suggestive linkage signals on chromosomes 9 and 16, respectively, with the highest multipoint nonparametric linkage signal on chromosome 16q23 at 99 cM (log of the odds, LOD=3.1) overlapping data published from the previous UCLA (University of California, Los Angeles) (LOD>1, approximately 95 cM) and Dutch (LOD>1, approximately 100 cM) studies. The second highest peak in this study was on chromosome 9q22 at 90 cM (LOD=2.13); both the previous UCLA and German studies also found some evidence of linkage at almost the same location (UCLA LOD=1.45 at 93 cM; German LOD=0.68 at 100 cM). The overlap of these two main peaks with previous findings suggests that loci linked to ADHD may lie within these regions. Meta-analysis or reanalysis of the raw data of all the available ADHD linkage scan data may help to clarify whether these represent true linked loci.

Asian Financial Linkages: The Case of Japan

OpenAIRE

Fialová, Anežka

2014-01-01

This work reviews the topic of international financial linkages, including theoretical definitions and the main methodological approaches of the empirical measurement based on vector autoregressive models. One of the approaches, the Spillover Index methodology based on Diebold & Yilmaz (2009), is then used to analyze the developments of financial linkages of the Japanese stock market in the period from 1995 to 2012. The attention is paid both to the relations with western developed economies ...

Removal of phosphate from eutrophic lakes through adsorption by in situ formation of magnesium hydroxide from diatomite.

Science.gov (United States)

Xie, Fazhi; Wu, Fengchang; Liu, Guijian; Mu, Yunsong; Feng, Chenglian; Wang, Huanhua; Giesy, John P

2014-01-01

Since in situ formation of Mg(OH)2 can efficiently sorb phosphate (PO4) from low concentrations in the environment, a novel dispersed magnesium oxide nanoflake-modified diatomite adsorbent (MOD) was developed for use in restoration of eutrophic lakes by removal of excess PO4. Various adsorption conditions, such as pH, temperature and contact time were investigated. Overall, sorption capacities increased with increasing temperature and contact time, and decreased with increasing pH. Adsorption of PO4 was well described by both the Langmuir isotherm and pseudo second-order models. Theoretical maximum sorption capacity of MOD for PO4 was 44.44-52.08 mg/g at experimental conditions. Characterization of PO4 adsorbed to MOD by use of X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and solid state (31)P nuclear magnetic resonance revealed that electrostatic attraction, surface complexation and chemical conversion in situ were the major forces in adsorption of PO4. Mg(OH)2 formed in situ had a net positive charge on the surface of the MOD that could adsorb PO4(3-) and HPO4(2-) anion to form surface complex and gradually convert to Mg3(PO4)2 and MgHPO4. Efficiency of removal of PO4 was 90% when 300 mg MOD/L was added to eutrophic lake water. Results presented here demonstrated the potential use of the MOD for restoration of eutrophic lakes by removal of excess PO4.

In situ effects of simulated overfishing and eutrophication on settlement of benthic coral reef invertebrates in the Central Red Sea.

KAUST Repository

Jessen, Christian

2014-04-08

In the Central Red Sea, healthy coral reefs meet intense coastal development, but data on the effects of related stressors for reef functioning are lacking. This in situ study therefore investigated the independent and combined effects of simulated overfishing through predator/grazer exclusion and simulated eutrophication through fertilizer addition on settlement of reef associated invertebrates on light-exposed and -shaded tiles over 4 months. At the end of the study period invertebrates had almost exclusively colonized shaded tiles. Algae were superior settling competitors on light-exposed tiles. On the shaded tiles, simulated overfishing prevented settlement of hard corals, but significantly increased settlement of polychaetes, while simulated eutrophication only significantly decreased hard coral settlement relative to controls. The combined treatment significantly increased settlement of bryozoans and bivalves compared to controls and individual manipulations, but significantly decreased polychaetes compared to simulated overfishing. These results suggest settlement of polychaetes and hard corals as potential bioindicators for overfishing and eutrophication, respectively, and settlement of bivalves and bryozoans for a combination of both. Therefore, if the investigated stressors are not controlled, phase shifts from dominance by hard corals to that by other invertebrates may occur at shaded reef locations in the Central Red Sea.

In situ effects of simulated overfishing and eutrophication on settlement of benthic coral reef invertebrates in the Central Red Sea.

Science.gov (United States)

Jessen, Christian; Voolstra, Christian R; Wild, Christian

2014-01-01

In the Central Red Sea, healthy coral reefs meet intense coastal development, but data on the effects of related stressors for reef functioning are lacking. This in situ study therefore investigated the independent and combined effects of simulated overfishing through predator/grazer exclusion and simulated eutrophication through fertilizer addition on settlement of reef associated invertebrates on light-exposed and -shaded tiles over 4 months. At the end of the study period invertebrates had almost exclusively colonized shaded tiles. Algae were superior settling competitors on light-exposed tiles. On the shaded tiles, simulated overfishing prevented settlement of hard corals, but significantly increased settlement of polychaetes, while simulated eutrophication only significantly decreased hard coral settlement relative to controls. The combined treatment significantly increased settlement of bryozoans and bivalves compared to controls and individual manipulations, but significantly decreased polychaetes compared to simulated overfishing. These results suggest settlement of polychaetes and hard corals as potential bioindicators for overfishing and eutrophication, respectively, and settlement of bivalves and bryozoans for a combination of both. Therefore, if the investigated stressors are not controlled, phase shifts from dominance by hard corals to that by other invertebrates may occur at shaded reef locations in the Central Red Sea.

Nance-Horan syndrome: linkage analysis in a family from The Netherlands

NARCIS (Netherlands)

Bergen, A. A.; ten Brink, J.; Schuurman, E. J.; Bleeker-Wagemakers, E. M.

1994-01-01

Linkage analysis was carried out in a Dutch family with Nance-Horan (NH) syndrome. Close linkage without recombination between NH and the Xp loci DXS207, DXS43, and DXS365 (zmax = 3.23) was observed. Multipoint linkage analysis and the analysis of recombinations in multiple informative meioses

PLAB and UK graduates’ performance on MRCP(UK) and MRCGP examinations: data linkage study

Science.gov (United States)

Wakeford, Richard

2014-01-01

Objectives To assess whether international medical graduates passing the two examinations set by the Professional and Linguistic Assessments Board (PLAB1 and PLAB2) of the General Medical Council (GMC) are equivalent to UK graduates at the end of the first foundation year of medical training (F1), as the GMC requires, and if not, to assess what changes in the PLAB pass marks might produce equivalence. Design Data linkage of GMC PLAB performance data with data from the Royal Colleges of Physicians and the Royal College of General Practitioners on performance of PLAB graduates and UK graduates at the MRCP(UK) and MRCGP examinations. Setting Doctors in training for internal medicine or general practice in the United Kingdom. Participants 7829, 5135, and 4387 PLAB graduates on their first attempt at MRCP(UK) Part 1, Part 2, and PACES assessments from 2001 to 2012 compared with 18 532, 14 094, and 14 376 UK graduates taking the same assessments; 3160 PLAB1 graduates making their first attempt at the MRCGP AKT during 2007-12 compared with 14 235 UK graduates; and 1411 PLAB2 graduates making their first attempt at the MRCGP CSA during 2010-12 compared with 6935 UK graduates. Main outcome measures Performance at MRCP(UK) Part 1, Part 2, and PACES assessments, and MRCGP AKT and CSA assessments in relation to performance on PLAB1 and PLAB2 assessments, as well as to International English Language Testing System (IELTS) scores. MRCP(UK), MRCGP, and PLAB results were analysed as marks relative to the pass mark at the first attempt. Results PLAB1 marks were a valid predictor of MRCP(UK) Part 1, MRCP(UK) Part 2, and MRCGP AKT (r=0.521, 0.390, and 0.490; all PIELTS scores correlated significantly with later performance, multiple regression showing that the effect of PLAB1 (β=0.496) was much stronger than the effect of IELTS (β=0.086). Changes to PLAB pass marks that would result in international medical graduate and UK medical graduate equivalence were assessed in two

PLAB and UK graduates' performance on MRCP(UK) and MRCGP examinations: data linkage study.

Science.gov (United States)

McManus, I C; Wakeford, Richard

2014-04-17

To assess whether international medical graduates passing the two examinations set by the Professional and Linguistic Assessments Board (PLAB1 and PLAB2) of the General Medical Council (GMC) are equivalent to UK graduates at the end of the first foundation year of medical training (F1), as the GMC requires, and if not, to assess what changes in the PLAB pass marks might produce equivalence. Data linkage of GMC PLAB performance data with data from the Royal Colleges of Physicians and the Royal College of General Practitioners on performance of PLAB graduates and UK graduates at the MRCP(UK) and MRCGP examinations. Doctors in training for internal medicine or general practice in the United Kingdom. 7829, 5135, and 4387 PLAB graduates on their first attempt at MRCP(UK) Part 1, Part 2, and PACES assessments from 2001 to 2012 compared with 18,532, 14,094, and 14,376 UK graduates taking the same assessments; 3160 PLAB1 graduates making their first attempt at the MRCGP AKT during 2007-12 compared with 14,235 UK graduates; and 1411 PLAB2 graduates making their first attempt at the MRCGP CSA during 2010-12 compared with 6935 UK graduates. Performance at MRCP(UK) Part 1, Part 2, and PACES assessments, and MRCGP AKT and CSA assessments in relation to performance on PLAB1 and PLAB2 assessments, as well as to International English Language Testing System (IELTS) scores. MRCP(UK), MRCGP, and PLAB results were analysed as marks relative to the pass mark at the first attempt. PLAB1 marks were a valid predictor of MRCP(UK) Part 1, MRCP(UK) Part 2, and MRCGP AKT (r=0.521, 0.390, and 0.490; all PIELTS scores correlated significantly with later performance, multiple regression showing that the effect of PLAB1 (β=0.496) was much stronger than the effect of IELTS (β=0.086). Changes to PLAB pass marks that would result in international medical graduate and UK medical graduate equivalence were assessed in two ways. Method 1 adjusted PLAB pass marks to equate median performance of PLAB

Harmful algal bloom removal and eutrophic water remediation by commercial nontoxic polyamine-co-polymeric ferric sulfate-modified soils.

Science.gov (United States)

Dai, Guofei; Zhong, Jiayou; Song, Lirong; Guo, Chunjing; Gan, Nanqin; Wu, Zhenbin

2015-07-01

Harmful algal bloom has posed great threat to drinking water safety worldwide. In this study, soils were combined with commercial nontoxic polyamine poly(epichlorohydrin-dimethylamine) (PN) and polymeric ferric sulfate (PFS) to obtain PN-PFS soils for Microcystis removal and eutrophic water remediation under static laboratory conditions. High pH and temperature in water could enhance the function of PN-PFS soil. Algal removal efficiency increased as soil particle size decreased or modified soil dose increased. Other pollutants or chemicals (such as C, P, and organic matter) in eutrophic water could participate and promote algal removal by PN-PFS soil; these pollutants were also flocculated. During PN-PFS soil application in blooming field samples, the removal efficiency of blooming Microcystis cells exceeded 99 %, the cyanotoxin microcystins reduced by 57 %. Water parameters (as TP, TN, SS, and SPC) decreased by about 90 %. CODMn, PO4-P, and NH4-N also sharply decreased by >45 %. DO and ORP in water improved. Netting and bridging effects through electrostatic attraction and complexation reaction could be the two key mechanisms of Microcystis flocculation and pollutant purification. Considering the low cost of PN-PFS soil and its nontoxic effect on the environment, we proposed that this soil combination could be applied to remove cyanobacterial bloom and remediate eutrophic water in fields.

Assessment of the Eutrophication-Related Environmental Parameters in Two Mediterranean Lakes by Integrating Statistical Techniques and Self-Organizing Maps.

Science.gov (United States)

Hadjisolomou, Ekaterini; Stefanidis, Konstantinos; Papatheodorou, George; Papastergiadou, Evanthia

2018-03-19

During the last decades, Mediterranean freshwater ecosystems, especially lakes, have been under severe pressure due to increasing eutrophication and water quality deterioration. In this article, we compared the effectiveness of different data analysis methods by assessing the contribution of environmental parameters to eutrophication processes. For this purpose, principal components analysis (PCA), cluster analysis, and a self-organizing map (SOM) were applied, using water quality data from two transboundary lakes of North Greece. SOM is considered as an advanced and powerful data analysis tool because of its ability to represent complex and nonlinear relationships among multivariate data sets. The results of PCA and cluster analysis agreed with the SOM results, although the latter provided more information because of the visualization abilities regarding the parameters' relationships. Besides nutrients that were found to be a key factor for controlling chlorophyll-a (Chl - a), water temperature was related positively with algal production, while the Secchi disk depth parameter was found to be highly important and negatively related toeutrophic conditions. In general, the SOM results were more specific and allowed direct associations between the water quality variables. Our work showed that SOMs can be used effectively in limnological studies to produce robust and interpretable results, aiding scientists and managers to cope with environmental problems such as eutrophication.

Assessment of the Eutrophication-Related Environmental Parameters in Two Mediterranean Lakes by Integrating Statistical Techniques and Self-Organizing Maps

Directory of Open Access Journals (Sweden)

Ekaterini Hadjisolomou

2018-03-01

Full Text Available During the last decades, Mediterranean freshwater ecosystems, especially lakes, have been under severe pressure due to increasing eutrophication and water quality deterioration. In this article, we compared the effectiveness of different data analysis methods by assessing the contribution of environmental parameters to eutrophication processes. For this purpose, principal components analysis (PCA, cluster analysis, and a self-organizing map (SOM were applied, using water quality data from two transboundary lakes of North Greece. SOM is considered as an advanced and powerful data analysis tool because of its ability to represent complex and nonlinear relationships among multivariate data sets. The results of PCA and cluster analysis agreed with the SOM results, although the latter provided more information because of the visualization abilities regarding the parameters’ relationships. Besides nutrients that were found to be a key factor for controlling chlorophyll-a (Chl-a, water temperature was related positively with algal production, while the Secchi disk depth parameter was found to be highly important and negatively related toeutrophic conditions. In general, the SOM results were more specific and allowed direct associations between the water quality variables. Our work showed that SOMs can be used effectively in limnological studies to produce robust and interpretable results, aiding scientists and managers to cope with environmental problems such as eutrophication.

Genome scan for linkage to Gilles de la Tourette syndrome

Energy Technology Data Exchange (ETDEWEB)

Barr, C.L.; Livingston, J.; Williamson, R. [and others

1994-09-01

Gilles de la Tourette Syndrome (TS) is a familial, neuropsychiatric disorder characterized by chronic, intermittent motor and vocal tics. In addition to tics, affected individuals frequently display symptoms such as attention-deficit hyperactivity disorder and/or obsessive compulsive disorder. Genetic analyses of family data have suggested that susceptibility to the disorder is most likely due to a single genetic locus with a dominant mode of transmission and reduced penetrance. In the search for genetic linkage for TS, we have collected well-characterized pedigrees with multiple affected individuals on whom extensive diagnostic evaluations have been done. The first stage of our study is to scan the genome systematically using a panel of uniformly spaced (10 to 20 cM), highly polymorphic, microsatellite markers on 5 families segregating TS. To date, 290 markers have been typed and 3,660 non-overlapping cM of the genome have been excluded for possible linkage under the assumption of genetic homogeneity. Because of the possibility of locus heterogeneity overall summed exclusion is not considered tantamount to absolute exclusion of a disease locus in that region. The results from each family are carefully evaluated and a positive lod score in a single family is followed up by typing closely linked markers. Linkage to TS was examined by two-point analysis using the following genetic model: single autosomal dominant gene with gene frequency .003 and maximum penetrance of .99. An age-of-onset correction is included using a linear function increasing from age 2 years to 21 years. A small rate of phenocopies is also incorporated into the model. Only individuals with TS or CMT according to DSM III-R criteria were regarded as affected for the purposes of this summary. Additional markers are being tested to provide coverage at 5 cM intervals. Moreover, we are currently analyzing the data non-parametrically using the Affected-Pedigree-Member Method of linkage analysis.

Replication of linkage to quantitative trait loci: variation in location and magnitude of the lod score.

Science.gov (United States)

Hsueh, W C; Göring, H H; Blangero, J; Mitchell, B D

2001-01-01

Replication of linkage signals from independent samples is considered an important step toward verifying the significance of linkage signals in studies of complex traits. The purpose of this empirical investigation was to examine the variability in the precision of localizing a quantitative trait locus (QTL) by analyzing multiple replicates of a simulated data set with the use of variance components-based methods. Specifically, we evaluated across replicates the variation in both the magnitude and the location of the peak lod scores. We analyzed QTLs whose effects accounted for 10-37% of the phenotypic variance in the quantitative traits. Our analyses revealed that the precision of QTL localization was directly related to the magnitude of the QTL effect. For a QTL with effect accounting for > 20% of total phenotypic variation, > 90% of the linkage peaks fall within 10 cM from the true gene location. We found no evidence that, for a given magnitude of the lod score, the presence of interaction influenced the precision of QTL localization.

Linkage of the Canadian Study of Health and Aging to provincial administrative health care databases in Nova Scotia.

Science.gov (United States)

Yip, A M; Kephart, G; Rockwood, K

2001-01-01

The Canadian Study of Health and Aging (CSHA) was a cohort study that included 528 Nova Scotian community-dwelling participants. Linkage of CSHA and provincial Medical Services Insurance (MSI) data enabled examination of health care utilization in this subsample. This article discusses methodological and ethical issues of database linkage and explores variation in the use of health services by demographic variables and health status. Utilization over 24 months following baseline was extracted from MSI's physician claims, hospital discharge abstracts, and Pharmacare claims databases. Twenty-nine subjects refused consent for access to their MSI file; health card numbers for three others could not be retrieved. A significant difference in healthcare use by age and self-rated health was revealed. Linkage of population-based data with provincial administrative health care databases has the potential to guide health care planning and resource allocation. This process must include steps to ensure protection of confidentiality. Standard practices for linkage consent and routine follow-up should be adopted. The Canadian Study of Health and Aging (CSHA) began in 1991-92 to explore dementia, frailty, and adverse health outcomes (Canadian Study of Health and Aging Working Group, 1994). The original CSHA proposal included linkage to provincial administrative health care databases by the individual CSHA study centers to enhance information on health care utilization and outcomes of study participants. In Nova Scotia, the Medical Services Insurance (MSI) administration, which drew the sampling frame for the original CSHA, did not retain the list of corresponding health card numbers. Furthermore, consent for this access was not asked of participants at the time of the first interview. The objectives of this study reported here were to examine the feasibility and ethical considerations of linking data from the CSHA to MSI utilization data, and to explore variation in health

The Barley Chromosome 5 Linkage Map

DEFF Research Database (Denmark)

Jensen, J.; Jørgensen, Jørgen Helms

1975-01-01

The distances between nine loci on barley chromosome 5 have been studied in five two-point tests, three three-point tests, and one four-point test. Our previous chromosome 5 linkage map, which contained eleven loci mapped from literature data (Jensen and Jørgensen 1975), is extended with four loci......-position is fixed on the map by a locus (necl), which has a good marker gene located centrally in the linkage group. The positions of the other loci are their distances in centimorgans from the 0-position; loci in the direction of the short chromosome arm are assigned positive values and those...

Clause linkage in Ket

NARCIS (Netherlands)

Nefedov, Andrey

2015-01-01

This work provides a typologically oriented description of clause linkage strategies in Ket, a highly endangered language spoken in Central Siberia. It is now the only surviving member of the Yeniseian language family with the last remaining speakers residing in the north of Russia’s Krasnoyarsk

The use of mechanistic descriptions of algal growth and zooplankton grazing in an estuarine eutrophication model

Science.gov (United States)

Baird, M. E.; Walker, S. J.; Wallace, B. B.; Webster, I. T.; Parslow, J. S.

2003-03-01

A simple model of estuarine eutrophication is built on biomechanical (or mechanistic) descriptions of a number of the key ecological processes in estuaries. Mechanistically described processes include the nutrient uptake and light capture of planktonic and benthic autotrophs, and the encounter rates of planktonic predators and prey. Other more complex processes, such as sediment biogeochemistry, detrital processes and phosphate dynamics, are modelled using empirical descriptions from the Port Phillip Bay Environmental Study (PPBES) ecological model. A comparison is made between the mechanistically determined rates of ecological processes and the analogous empirically determined rates in the PPBES ecological model. The rates generally agree, with a few significant exceptions. Model simulations were run at a range of estuarine depths and nutrient loads, with outputs presented as the annually averaged biomass of autotrophs. The simulations followed a simple conceptual model of eutrophication, suggesting a simple biomechanical understanding of estuarine processes can provide a predictive tool for ecological processes in a wide range of estuarine ecosystems.

Intragroup emotions: physiological linkage and social presence

Directory of Open Access Journals (Sweden)

Simo eJärvelä

2016-02-01

Full Text Available We investigated how technologically mediating two different components of emotion – communicative expression and physiological state – to group members affects physiological linkage and self-reported feelings in a small group during video viewing. In different conditions the availability of second screen text chat (communicative expression and visualization of group level physiological heart rates and their dyadic linkage (physiology was varied. Within this four person group two participants formed a physically co-located dyad and the other two were individually situated in two separate rooms. We found that text chat always increased heart rate synchrony but HR visualization only with non-co-located dyads. We also found that physiological linkage was strongly connected to self-reported social presence. The results encourage further exploration of the possibilities of sharing group member’s physiological components of emotion by technological means to enhance mediated communication and strengthen social presence.

Intragroup Emotions: Physiological Linkage and Social Presence

Science.gov (United States)

Järvelä, Simo; Kätsyri, Jari; Ravaja, Niklas; Chanel, Guillaume; Henttonen, Pentti

2016-01-01

We investigated how technologically mediating two different components of emotion—communicative expression and physiological state—to group members affects physiological linkage and self-reported feelings in a small group during video viewing. In different conditions the availability of second screen text chat (communicative expression) and visualization of group level physiological heart rates and their dyadic linkage (physiology) was varied. Within this four person group two participants formed a physically co-located dyad and the other two were individually situated in two separate rooms. We found that text chat always increased heart rate synchrony but HR visualization only with non-co-located dyads. We also found that physiological linkage was strongly connected to self-reported social presence. The results encourage further exploration of the possibilities of sharing group member's physiological components of emotion by technological means to enhance mediated communication and strengthen social presence. PMID:26903913

Identifying and Mapping Linkages between Actors in the Climate ...

African Journals Online (AJOL)

Promoting innovations in climate change requires innovation partnerships and linkages and also creating an enabling environment for actors. The paper reviewed available information on the identification and mapping of linkages between actors in the climate change innovation system. The findings showed different ...

Solid-Phase Synthesis of RNA Analogs Containing Phosphorodithioate Linkages.

Science.gov (United States)

Yang, Xianbin

2017-09-18

The oligoribonucleotide phosphorodithioate (PS2-RNA) modification uses two sulfur atoms to replace two non-bridging oxygen atoms at an internucleotide phosphorodiester backbone linkage. Like a natural phosphodiester RNA backbone linkage, a PS2-modified backbone linkage is achiral at phosphorus. PS2-RNAs are highly stable to nucleases and several in vitro assays have demonstrated their biological activity. For example, PS2-RNAs silenced mRNA in vitro and bound to protein targets in the form of PS2-aptamers (thioaptamers). Thus, the interest in and promise of PS2-RNAs has drawn attention to synthesizing, isolating, and characterizing these compounds. RNA-thiophosphoramidite monomers are commercially available from AM Biotechnologies and this unit describes an effective methodology for solid-phase synthesis, deprotection, and purification of RNAs having PS2 internucleotide linkages. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

Effects of Worldwide Population Subdivision on ALDH2 Linkage Disequilibrium

OpenAIRE

Peterson, Raymond J.; Goldman, David; Long, Jeffrey C.

1999-01-01

The effect of human population subdivision on linkage disequilibrium has previously been studied for unlinked genes. However, no study has focused on closely linked polymorphisms or formally partitioned linkage disequilibrium within and among worldwide populations. With an emphasis on population subdivision, the goal of this paper is to investigate the causes of linkage disequilibrium in ALDH2, the gene that encodes aldehyde dehydrogenase 2. Haplotypes for 756 people from 17 populations acros...

Performance of surface and subsurface flow constructed wetlands treating eutrophic waters.

Science.gov (United States)

Hernández-Crespo, C; Gargallo, S; Benedito-Durá, V; Nácher-Rodríguez, Beatriz; Rodrigo-Alacreu, M A; Martín, M

2017-10-01

Three medium size constructed wetlands (CWs) with a total surface of 90ha are working since 2009 in the Albufera de Valencia Natural Park (Spain). Two of them are fed with eutrophic waters from l'Albufera Lake. Their objectives are both reduce the phytoplankton biomass and increase the biodiversity; consequently, improved water quality is returned to the lake. A "science based governance" of these CWs is ongoing inside the LIFE+12 Albufera Project to demonstrate the environmental benefits of these features. In this paper, results and relationships among hydraulic operation, physicochemical variables and plankton in two different CWs typologies, five free water surface CW (FWSCW) and one horizontal subsurface flow CW (HSSFCW), were analysed showing that CWs were capable of improving the water quality and biodiversity but showing clear differences depending on the CW type. The CWs worked under different hydraulic load rates (HLR) from <0.12 to 54.75myr -1 . Inflow water quality was typical from eutrophic waters with mean values of chlorophyll a (Chl a) about 22-90μgChlal -1 and mean total phosphorus (TP) between 0.122 and 0.337mgl -1 . The main conclusion is that HSSFCW was much more efficient than FWSCW in the removal of organic matter, suspended solids and nutrients. The biological role of several shallow lagoons located at the end of the CWs has also been evaluated, showing that they contribute to increase the zooplankton biomass, a key factor to control the phytoplankton blooms. Copyright © 2017 Elsevier B.V. All rights reserved.

Nutrient content in macrophyta collected from southern Baltic Sea beaches in relation to eutrophication and biogas production

Energy Technology Data Exchange (ETDEWEB)

Bucholc, K.; Szymczak-Żyła, M.; Lubecki, L. [Marine Pollution Laboratory, Institute of Oceanology, Polish Academy of Sciences, ul. Powstańców Warszawy 55, 81-712 Sopot (Poland); Zamojska, A. [University of Gdańsk, Department of Econometrics, ul. Armii Krajowej 101, 81-824 Sopot (Poland); Hapter, P. [Marine Pollution Laboratory, Institute of Oceanology, Polish Academy of Sciences, ul. Powstańców Warszawy 55, 81-712 Sopot (Poland); Tjernström, E. [Environmental Department, Trelleborg Municipality, Algatan 13, 231 83 Trelleborg (Sweden); Kowalewska, G. [Marine Pollution Laboratory, Institute of Oceanology, Polish Academy of Sciences, ul. Powstańców Warszawy 55, 81-712 Sopot (Poland)

2014-03-01

One of the signs of eutrophication is the excessive growth of opportunistic macroalgae, a worldwide phenomenon also observed in the Baltic Sea. Mats of macroalgae may drift long distances and accumulate at the seashore, considerably decreasing the recreational value of beaches. The matter accumulating at the shore is treated usually as waste. However, it could be used, for example, as a resource for biogas production. The aim of this work was to verify the hypothesis that collecting of macrophyta accumulating on the beach and potential usage of this material for biogas production will decrease nutrient reserves in the sea to counteract eutrophication and the increase in greenhouse effects. Samples of macrophyta were collected in 2011 and 2012 and analysed for their C, N, and P contents, and degree of degradation (% Chl-a in the sum of chloropigments-a); the results were analysed statistically. The nutrient content was studied in macrophyta accumulating on the beach (Sopot, Gulf of Gdańsk, Poland) and for comparison, macrophyta collected from their habitats in less nutrient polluted area (off the Skåre coast, Trelleborg, Sweden). The nutrient content (N, P) in macrophyta depends primarily on their morphology and only secondarily on environmental nutrient pollution. Collecting the macrophyta biomass accumulating on beaches will not significantly change the eutrophication of the Baltic as a whole; any improvements in this respect are likely to be on a local scale only. Collecting macrophyta removes more nitrogen than phosphorous, so this would decrease the N/P ratio in seawater. This macrophyta biomass is a substantial reserve of renewable energy, which could be utilized with the appropriate technology for biomass collection/preservation and biofuel production as an additive to other carbon-rich biomasses. And the biofuel production should be evaluated not only from the standpoint of economic efficiency but also from the environmental point of view. - Highlights: �

Macrophytes and periphyton carbon subsidies to bacterioplankton and zooplankton in a shallow eutrophic lake in tropical China

NARCIS (Netherlands)

de Kluijver, A.; Ning, J.; Liu, Z.; Jeppesen, E.; Gulati, R.D.; Middelburg, J.J.

The subsidy of carbon derived from macrophytes and associated periphyton to bacterioplankton and zooplankton in subtropical shallow eutrophic Huizhou West Lake in China was analyzed using carbon stable isotope signatures. A restored part of the lake dominated by macrophytes was compared with an

Macrophytes and periphyton carbon subsidies to bacterioplankton and zooplankton in a shallow eutrophic lake in tropical China

NARCIS (Netherlands)

de Kluijver, A.; Ning, J.; Liu, Z.; Jeppesen, E.; Gulati, R.D.; Middelburg, J.J.

2015-01-01

The subsidy of carbon derived from macrophytes and associated periphyton to bacterioplankton and zooplankton in subtropical shallow eutrophic Huizhou West Lake in China was analyzed using carbon stable isotope signatures. A restored part of the lake dominated by macrophytes was compared with an

Young people’s views about consenting to data linkage: findings from the PEARL qualitative study

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Suzanne Audrey

2016-03-01

Full Text Available Abstract Background Electronic administrative data exist in several domains which, if linked, are potentially useful for research. However, benefits from data linkage should be considered alongside risks such as the threat to privacy. Avon Longitudinal Study of Parents and Children (ALSPAC is a birth cohort study. The Project to Enhance ALSPAC through Record Linkage (PEARL was established to enrich the ALSPAC resource through linkage between ALSPAC participants and routine sources of health and social data. Qualitative research was incorporated in the PEARL study to examine participants’ views about data linkage and inform approaches to information sharing. This paper focusses on issues of consent. Methods Digitally recorded interviews were conducted with 55 participants aged 17–19 years. Terms and processes relating to consent, anonymization and data linkage were explained to interviewees. Scenarios were used to prompt consideration of linking different sources of data, and whether consent should be requested. Interview recordings were fully transcribed. Thematic analysis was undertaken using the Framework approach. Results Participant views on data linkage appeared to be most influenced by: considerations around the social sensitivity of the research question, and; the possibility of tangible health benefits in the public interest. Some participants appeared unsure about the effectiveness of anonymization, or did not always view effective anonymization as making consent unnecessary. This was related to notions of ownership of personal information and etiquette around asking permission for secondary use. Despite different consent procedures being explained, participants tended to equate consent with ‘opt-in’ consent through which participants are ‘asked’ if their data can be used for a specific study. Participants raising similar concerns came to differing conclusions about whether consent was needed. Views changed when presented

Arctic-midlatitude weather linkages in North America

Science.gov (United States)

Overland, James E.; Wang, Muyin

2018-06-01

There is intense public interest in whether major Arctic changes can and will impact midlatitude weather such as cold air outbreaks on the central and east side of continents. Although there is progress in linkage research for eastern Asia, a clear gap is conformation for North America. We show two stationary temperature/geopotential height patterns where warmer Arctic temperatures have reinforced existing tropospheric jet stream wave amplitudes over North America: a Greenland/Baffin Block pattern during December 2010 and an Alaska Ridge pattern during December 2017. Even with continuing Arctic warming over the past decade, other recent eastern US winter months were less susceptible for an Arctic linkage: the jet stream was represented by either zonal flow, progressive weather systems, or unfavorable phasing of the long wave pattern. The present analysis lays the scientific controversy over the validity of linkages to the inherent intermittency of jet stream dynamics, which provides only an occasional bridge between Arctic thermodynamic forcing and extended midlatitude weather events.

A microsatellite linkage map of Drosophila mojavensis

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Schully Sheri

2004-05-01

Full Text Available Abstract Background Drosophila mojavensis has been a model system for genetic studies of ecological adaptation and speciation. However, despite its use for over half a century, no linkage map has been produced for this species or its close relatives. Results We have developed and mapped 90 microsatellites in D. mojavensis, and we present a detailed recombinational linkage map of 34 of these microsatellites. A slight excess of repetitive sequence was observed on the X-chromosome relative to the autosomes, and the linkage groups have a greater recombinational length than the homologous D. melanogaster chromosome arms. We also confirmed the conservation of Muller's elements in 23 sequences between D. melanogaster and D. mojavensis. Conclusions The microsatellite primer sequences and localizations are presented here and made available to the public. This map will facilitate future quantitative trait locus mapping studies of phenotypes involved in adaptation or reproductive isolation using this species.

High-frequency stock linkage and multi-dimensional stationary processes

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Wang, Xi; Bao, Si; Chen, Jingchao

2017-02-01

In recent years, China's stock market has experienced dramatic fluctuations; in particular, in the second half of 2014 and 2015, the market rose sharply and fell quickly. Many classical financial phenomena, such as stock plate linkage, appeared repeatedly during this period. In general, these phenomena have usually been studied using daily-level data or minute-level data. Our paper focuses on the linkage phenomenon in Chinese stock 5-second-level data during this extremely volatile period. The method used to select the linkage points and the arbitrage strategy are both based on multi-dimensional stationary processes. A new program method for testing the multi-dimensional stationary process is proposed in our paper, and the detailed program is presented in the paper's appendix. Because of the existence of the stationary process, the strategy's logarithmic cumulative average return will converge under the condition of the strong ergodic theorem, and this ensures the effectiveness of the stocks' linkage points and the more stable statistical arbitrage strategy.

Autosomal dominant distal myopathy: Linkage to chromosome 14

Energy Technology Data Exchange (ETDEWEB)

Laing, N.G.; Laing, B.A.; Wilton, S.D.; Dorosz, S.; Mastaglia, F.L.; Kakulas, B.A. [Australian Neuromuscular Research Institute, Perth (Australia); Robbins, P.; Meredith, C.; Honeyman, K.; Kozman, H.

1995-02-01

We have studied a family segregating a form of autosomal dominant distal myopathy (MIM 160500) and containing nine living affected individuals. The myopathy in this family is closest in clinical phenotype to that first described by Gowers in 1902. A search for linkage was conducted using microsatellite, VNTR, and RFLP markers. In total, 92 markers on all 22 autosomes were run. Positive linkage was obtained with 14 of 15 markers tested on chromosome 14, with little indication of linkage elsewhere in the genome. Maximum two-point LOD scores of 2.60 at recombination fraction .00 were obtained for the markers MYH7 and D14S64 - the family structure precludes a two-point LOD score {ge} 3. Recombinations with D14S72 and D14S49 indicate that this distal myopathy locus, MPD1, should lie between these markers. A multipoint analysis assuming 100% penetrance and using the markers D14S72, D14S50, MYH7, D14S64, D14S54, and D14S49 gave a LOD score of exactly 3 at MYH7. Analysis at a penetrance of 80% gave a LOD score of 2.8 at this marker. This probable localization of a gene for distal myopathy, MPD1, on chromosome 14 should allow other investigators studying distal myopathy families to test this region for linkage in other types of the disease, to confirm linkage or to demonstrate the likely genetic heterogeneity. 24 refs., 3 figs., 1 tab.

The National Eutrophication Survey: lake characteristics and historical nutrient concentrations

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J. Stachelek

2018-01-01

Full Text Available Historical ecological surveys serve as a baseline and provide context for contemporary research, yet many of these records are not preserved in a way that ensures their long-term usability. The National Eutrophication Survey (NES database is currently only available as scans of the original reports (PDF files with no embedded character information. This limits its searchability, machine readability, and the ability of current and future scientists to systematically evaluate its contents. The NES data were collected by the US Environmental Protection Agency between 1972 and 1975 as part of an effort to investigate eutrophication in freshwater lakes and reservoirs. Although several studies have manually transcribed small portions of the database in support of specific studies, there have been no systematic attempts to transcribe and preserve the database in its entirety. Here we use a combination of automated optical character recognition and manual quality assurance procedures to make these data available for analysis. The performance of the optical character recognition protocol was found to be linked to variation in the quality (clarity of the original documents. For each of the four archival scanned reports, our quality assurance protocol found an error rate between 5.9 and 17 %. The goal of our approach was to strike a balance between efficiency and data quality by combining entry of data by hand with digital transcription technologies. The finished database contains information on the physical characteristics, hydrology, and water quality of about 800 lakes in the contiguous US (Stachelek et al.(2017, https://doi.org/10.5063/F1639MVD. Ultimately, this database could be combined with more recent studies to generate meta-analyses of water quality trends and spatial variation across the continental US.

The National Eutrophication Survey: lake characteristics and historical nutrient concentrations

Science.gov (United States)

Stachelek, Joseph; Ford, Chanse; Kincaid, Dustin; King, Katelyn; Miller, Heather; Nagelkirk, Ryan

2018-01-01

Historical ecological surveys serve as a baseline and provide context for contemporary research, yet many of these records are not preserved in a way that ensures their long-term usability. The National Eutrophication Survey (NES) database is currently only available as scans of the original reports (PDF files) with no embedded character information. This limits its searchability, machine readability, and the ability of current and future scientists to systematically evaluate its contents. The NES data were collected by the US Environmental Protection Agency between 1972 and 1975 as part of an effort to investigate eutrophication in freshwater lakes and reservoirs. Although several studies have manually transcribed small portions of the database in support of specific studies, there have been no systematic attempts to transcribe and preserve the database in its entirety. Here we use a combination of automated optical character recognition and manual quality assurance procedures to make these data available for analysis. The performance of the optical character recognition protocol was found to be linked to variation in the quality (clarity) of the original documents. For each of the four archival scanned reports, our quality assurance protocol found an error rate between 5.9 and 17 %. The goal of our approach was to strike a balance between efficiency and data quality by combining entry of data by hand with digital transcription technologies. The finished database contains information on the physical characteristics, hydrology, and water quality of about 800 lakes in the contiguous US (Stachelek et al.(2017), https://doi.org/10.5063/F1639MVD). Ultimately, this database could be combined with more recent studies to generate meta-analyses of water quality trends and spatial variation across the continental US.

Determination and occurrence of retinoids in a eutrophic lake (Taihu Lake, China): cyanobacteria blooms produce teratogenic retinal.

Science.gov (United States)

Wu, Xiaoqin; Jiang, Jieqiong; Hu, Jianying

2013-01-15

Besides retinoic acids (RAs), some retinoids such as retinal (RAL) and retinol (ROH), which are considered as RA precursors in vertebrates, are also reported to be teratogenic agents. In this study we investigated four RA precursors including RAL, ROH, retinyl palmitate, and β-carotene in the eutrophic Taihu Lake, China, by developing a sensitive analytical method. RAL and β-carotene were widely detected in natural cyanobacteria blooms and lake water. Intracellular concentrations of RAL and β-carotene in blooms were 9.4 to 6.9 × 10(3) and 3.4 to 1.8 × 10(5) ng L(-1), respectively, and their concentrations in lake water were up to 1.4 × 10 ng L(-1) (RAL) and 9.8 × 10(2) ng L(-1) (β-carotene). The good correlation between intracellular concentrations of RAL and RAs implied that RAL was involved in the production of RAs by cyanobacteria blooms. Further examination of 39 cyanobacteria and algae species revealed that most species could produce RAL and β-carotene. The greatest amount of RAL was found in Chlamydomonas sp. (FACHB-715; 1.9 × 10(3) ng g(-1) dry weight). As the main cyanobacteria in Taihu Lake, many Microcystis species could produce high amounts of RAL and were thought to greatly contribute to the production of RAL measured in the blooms. Productions of RAL and β-carotene by cyanobacteria were associated with species, origin location, and growth stage. The results in this study present the existence of a potential risk to aquatic animals living in a eutrophic environment from a high concentration of RAL in cyanobacteria blooms and also provide a clue for further investigating the mechanism underlying the biosynthetic pathway of RAs in cyanobacteria and algae.

In situ effects of simulated overfishing and eutrophication on settlement of benthic coral reef invertebrates in the Central Red Sea

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Christian Jessen

2014-04-01

Full Text Available In the Central Red Sea, healthy coral reefs meet intense coastal development, but data on the effects of related stressors for reef functioning are lacking. This in situ study therefore investigated the independent and combined effects of simulated overfishing through predator/grazer exclusion and simulated eutrophication through fertilizer addition on settlement of reef associated invertebrates on light-exposed and -shaded tiles over 4 months. At the end of the study period invertebrates had almost exclusively colonized shaded tiles. Algae were superior settling competitors on light-exposed tiles. On the shaded tiles, simulated overfishing prevented settlement of hard corals, but significantly increased settlement of polychaetes, while simulated eutrophication only significantly decreased hard coral settlement relative to controls. The combined treatment significantly increased settlement of bryozoans and bivalves compared to controls and individual manipulations, but significantly decreased polychaetes compared to simulated overfishing. These results suggest settlement of polychaetes and hard corals as potential bioindicators for overfishing and eutrophication, respectively, and settlement of bivalves and bryozoans for a combination of both. Therefore, if the investigated stressors are not controlled, phase shifts from dominance by hard corals to that by other invertebrates may occur at shaded reef locations in the Central Red Sea.

Plant component features of forest-bog ecotones of eutrophic paludification in the south of boreal forest zone of West Siberia

Science.gov (United States)

Klimova, N. V.; Chernova, N. A.; Pologova, N. N.

2018-03-01

Paludified forests formed in transitional forest-bog zone aren’t studied enough, inspite of its high expected diversity and large areas in the south of boreal forest zone of West Siberia. In this article wet birch (Betula pubescens) forests of forest-bog ecotones of eutrophic paludification are investigated on Vasyugan plain with nutrient-rich calcareous clays as soil-forming rocks. Species diversity and ecocoenotic structure of these phytocoenoses are discussed. They correlated with wetness and nutrient-availability of habitats evaluated with indicator values of plants. The participation of hydrophylous species is increasing as wetness of habitats increasing in the forest-to-bog direction like in mesotrophic paludification series. However the number of species is higher in the phytocoenoses of eutrophic paludification. The share of species required to nutrient availability is also higher, both in number and in abundance. A lot of these species are usual for eutrophic boreal forested swamps with groundwater input and absent in forests of mesotrophic paludification. Accordingly the nutrient-availability of habitats is also higher. All these features we connect with birch to be a forest forming species instead of dark-coniferous and with the influence of nutrient-rich parent rocks, which is evident in forest-bog ecotones of Vasyugan plain gradually decreasing together with peat horizon thickening.

In vitro controlled release of cisplatin from gold-carbon nanobottles via cleavable linkages

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Li J

2015-12-01

Full Text Available Jian Li,1 Sia Lee Yoong,2 Wei Jiang Goh,2 Bertrand Czarny,1 Zhi Yang,1 Kingshuk Poddar,2,3 Michal M Dykas,2,3 Abhijeet Patra,2,3 T Venkatesan,2,3 Tomasz Panczyk,4 Chengkuo Lee,5 Giorgia Pastorin1–3 1Department of Pharmacy, National University of Singapore, 2NUS Graduate School for Integrative Sciences and Engineering, Centre for Life Sciences (CeLS, 3NUSNNI-NanoCore, National University of Singapore, Singapore; 4Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Cracow, Poland; 5Department of Electrical and Computer Engineering, National University of Singapore, Singapore Abstract: Carbon nanotubes’ (CNTs hollow interior space has been explored for biomedical applications, such as drug repository against undesirable inactivation. To further devise CNTs as smart material for controlled release of cargo molecules, we propose the concept of “gold-carbon nanobottles”. After encapsulating cis-diammineplatinum(II dichloride (cisplatin, CDDP in CNTs, we covalently attached gold nanoparticles (AuNPs at the open-tips of CNTs via different cleavable linkages, namely hydrazine, ester, and disulfide-containing linkages. Compared with our previous study in which more than 80% of CDDP leaked from CNTs in 2 hours, AuNPs were found to significantly decrease such spontaneous release to <40%. In addition, CDDP release from AuNP-capped CNTs via disulfide linkage was selectively enhanced by twofolds in reducing conditions (namely with 1 mM dithiothreitol [DTT], which mimic the intracellular environment. We treated human colon adenocarcinoma cells HCT116 with our CDDP-loaded gold-carbon nanobottles and examined the cell viability using lactate dehydrogenase assay. Interestingly, we found that our nanobottles with cleavable disulfide linkage exerted stronger cytotoxic effect in HCT116 compared with normal human fetal lung fibroblast cells IMR-90. Therefore, we infer that our nanobottles strategy with inbuilt disulfide linkage could

Are the Lake Victoria fisheries threatened by exploitation or eutrophication? Towards an ecosystem-based approach to management

NARCIS (Netherlands)

Kolding, J.; Zwieten, van P.A.M.; Mkumbo, O.; Silsbe, G.; Hecky, R.

2008-01-01

Lake Victoria’s ecosystem has shown fundamental changes over its past recorded history in terms of nutrient loadings, productivity, faunal composition and fisheries. As yet, however, no attempt has been made to link the driving processes of eutrophication and fisheries to understand the feedback

Eutrophication and Dreissena invasion as drivers of biodiversity: a century of change in the mollusc community of Oneida Lake.

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Vadim A Karatayev

Full Text Available Changes in nutrient loading and invasive species are among the strongest human-driven disturbances in freshwater ecosystems, but our knowledge on how they affect the biodiversity of lakes is still limited. We conducted a detailed historical analysis of the mollusc community of Oneida Lake based on our comprehensive lakewide study in 2012 and previous surveys dating back to 1915. In the early 20th century, the lake had a high water clarity, with abundant macrophytes and benthic algae, and hosted the most diverse molluscan community in New York State, including 32 gastropod and 9 unionid species. By the 1960s, lake turbidity increased during a period of anthropogenic eutrophication, resulting in a 38% decline in species richness and a 95% reduction in abundance of native gastropods grazing on benthic algae. Following the invasion of Dreissena spp. in 1991 and subsequent increases in water clarity, native gastropod species richness expanded by 37% and abundance increased 20-fold by 2012. In contrast, filter-feeding unionids were unaffected by increased turbidity during the period of eutrophication but were extirpated by dreissenids. Through contrasting effects on turbidity, eutrophication and Dreissena spp. have likely driven the observed changes in native grazing gastropods by affecting the abundance of light-limited benthic algae. Given the high species richness and ecological importance of benthic grazers, monitoring and managing turbidity is important in preserving molluscan diversity.

A model for describing the eutrophication in a heavily regulated coastal lagoon. Application to the Albufera of Valencia (Spain).

Science.gov (United States)

del Barrio Fernández, Pilar; Gómez, Andrés García; Alba, Javier García; Díaz, César Álvarez; Revilla Cortezón, José Antonio

2012-12-15

A simplified two-dimensional eutrophication model was developed to simulate temporal and spatial variations of chlorophyll-a in heavily regulated coastal lagoons. This model considers the hydrodynamics of the whole study area, the regulated connexion of the lagoon with the sea, the variability of the input and output nutrient loads, the flux from the sediments to the water column, the phytoplankton growth and mortality kinetics, and the zooplankton grazing. The model was calibrated and validated by applying it to the Albufera of Valencia, a hypertrophic system whose connection to the sea is strongly regulated by a system of sluice-gates. The calibration and validation results presented a significant agreement between the model and the data obtained in several surveys. The accuracy was evaluated using a quantitative analysis, in which the average uncertainty of the model prediction was less than 6%. The results confirmed an expected phytoplankton bloom in April and October, achieving mean maximum values around 250 μg l(-1) of chlorophyll-a. A mass balance revealed that the eutrophication process is magnified by the input loads of nutrients, mainly from the sediments, as well as by the limited connection of the lagoon with the sea. This study has shown that the developed model is an efficient tool to manage the eutrophication problem in heavily regulated coastal lagoons. Copyright © 2012 Elsevier Ltd. All rights reserved.

A longitudinal study of childhood social behaviour : Inter-informant agreement, inter-context agreement, and social preference linkages

NARCIS (Netherlands)

Kuppens, Sofie; Grietens, Hans; Onghena, Patrick; Michiels, Daisy

2009-01-01

This study examined inter-informant agreement, inter-context agreement, and social preference linkages for social behaviour subtypes. On two occasions, data was collected on 600 children (8-10 years old) via mother, father, teacher, and peer reports. Informant reports converged within each context

Autism Spectrum Disorders and Assisted Reproductive Technology: Massachusetts 2004-2010 Population-based Results from Data Linkage Efforts

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Milton Kotelchuck

2017-04-01

The likelihood of an ASD diagnosis among singleton or twin children born to ART or SUBFERT mothers does not differ from FERTILE mothers. Population-based linkage of clinical and public health databases provides unique opportunities to examine longer-term outcomes of ART.

Precipitation and temperature drive seasonal variation in bioaccumulation of polycyclic aromatic hydrocarbons in the planktonic food webs of a subtropical shallow eutrophic lake in China.

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Tao, Yuqiang; Yu, Jing; Xue, Bin; Yao, Shuchun; Wang, Sumin

2017-04-01

Hydrophobic organic contaminants (HOCs) are toxic and ubiquitous in aquatic environments and pose great risks to aquatic organisms. Bioaccumulation by plankton is the first step for HOCs to enter aquatic food webs. Trophic status is considered to dominate variations in bioaccumulation of HOCs in plankton in temperate and frigid deep oligotrophic waters. However, long-term driving factors for bioaccumulation of HOCs in planktonic food webs of subtropical shallow eutrophic waters have not been well investigated. China has the largest subtropical lake density in the Northern Hemisphere. Due to limited field data, long-term variations in the bioaccumulation of HOCs in these lakes are almost unknown. Here we take Lake Xuanwu as an example to investigate long-term variations in the bioaccumulation, and biomagnification of polycyclic aromatic hydrocarbon (PAHs) in planktonic food webs of subtropical shallow eutrophic lakes in China, and elucidate the driving factors. Our results indicate that temperature rather than nutrients dominates long-term dynamics of planktonic biomass in this lake. Precipitation significantly enhances the concentrations of the PAHs, and total suspended particles, and consequently affects the distribution of the PAHs in the water column. Biomass dilution induced by temperature dominates bioaccumulation of the PAHs by both phytoplankton and zooplankton (copepods and cladocerans). Biomagnification of the PAHs from phytoplankton to zooplankton is positively correlated with temperature. Our study suggests that temperature and precipitation drive long-term variations in the bioaccumulation of the PAHs in the planktonic food webs of this subtropical shallow eutrophic lake. Lake Xuanwu has a similar mean annual temperature, annual precipitation, sunshine duration, and nutrient levels as other subtropical shallow eutrophic lakes in China. This study may also help to understand the bioaccumulation of HOCs in planktonic food webs of other subtropical shallow

Effects of snails, submerged plants and their coexistence on eutrophication in aquatic ecosystems

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Mo Shuqing

2017-01-01

Full Text Available Eutrophication resulting from nutrient loading to freshwater habitats is a severe problem, leading to degradation of ecosystems, including deterioration of water quality, water clarity and loss of biodiversity. Measures enacted to restore degraded freshwater ecosystems often involve the reintroduction of submerged plants and aquatic animals with beneficial ecological functions. In a mesocosm experiment, three treatments (planting with Vallisneria natans, introduction of the snail Bellamya aeruginosa and a combined treatment with both plants and snails were compared with controls to evaluate their effects on trophic state. The total nitrogen (TN, total phosphorus (TP and chlorophyll a (Chl a concentrations of planktonic and benthic algal samples were determined every two weeks, along with light intensity at the sediment surface. The plant-only treatment significantly reduced the TN levels and planktonic and benthic algal biomass and increased the light intensity at the sediment surface. The snail-only treatment reduced the concentrations of TN and reduced planktonic and benthic algal biomass. The combined treatment decreased the concentrations of TN and TP, reduced planktonic algal biomass and increased the light intensity on the sediment surface. The results indicate that while submerged plants and snails can both improve water quality, the most pronounced effect in aquatic ecosystems is achieved by their presence in combination. A combined reintroduction approach may provide enhanced benefits in restoring the eutrophic ecosystems, following the reduction of external nutrient loading.

Construction of a reference genetic linkage map for carnation (Dianthus caryophyllus L.).

Science.gov (United States)

Yagi, Masafumi; Yamamoto, Toshiya; Isobe, Sachiko; Hirakawa, Hideki; Tabata, Satoshi; Tanase, Koji; Yamaguchi, Hiroyasu; Onozaki, Takashi

2013-10-26

Genetic linkage maps are important tools for many genetic applications including mapping of quantitative trait loci (QTLs), identifying DNA markers for fingerprinting, and map-based gene cloning. Carnation (Dianthus caryophyllus L.) is an important ornamental flower worldwide. We previously reported a random amplified polymorphic DNA (RAPD)-based genetic linkage map derived from Dianthus capitatus ssp. andrezejowskianus and a simple sequence repeat (SSR)-based genetic linkage map constructed using data from intraspecific F2 populations; however, the number of markers was insufficient, and so the number of linkage groups (LGs) did not coincide with the number of chromosomes (x = 15). Therefore, we aimed to produce a high-density genetic map to improve its usefulness for breeding purposes and genetic research. We improved the SSR-based genetic linkage map using SSR markers derived from a genomic library, expression sequence tags, and RNA-seq data. Linkage analysis revealed that 412 SSR loci (including 234 newly developed SSR loci) could be mapped to 17 linkage groups (LGs) covering 969.6 cM. Comparison of five minor LGs covering less than 50 cM with LGs in our previous RAPD-based genetic map suggested that four LGs could be integrated into two LGs by anchoring common SSR loci. Consequently, the number of LGs corresponded to the number of chromosomes (x = 15). We added 192 new SSRs, eight RAPD, and two sequence-tagged site loci to refine the RAPD-based genetic linkage map, which comprised 15 LGs consisting of 348 loci covering 978.3 cM. The two maps had 125 SSR loci in common, and most of the positions of markers were conserved between them. We identified 635 loci in carnation using the two linkage maps. We also mapped QTLs for two traits (bacterial wilt resistance and anthocyanin pigmentation in the flower) and a phenotypic locus for flower-type by analyzing previously reported genotype and phenotype data. The improved genetic linkage maps and SSR markers developed

Eutrophication monitoring for Lake Superior's Chequamegon ...

Science.gov (United States)

A priority for the Lake Superior CSMI was to identify susceptible nearshore eutrophication areas. We developed an integrated sampling design to collect baseline data for Lake Superior’s Chequamegon Bay to understand how nearshore physical processes and tributary loading relate to observed chlorophyll concentrations. Sampling included ship-based water samples combined with vertical CTD casts, continuous in situ towing and data collected from an autonomous underwater glider. Sampling was conducted during June, July and September. The glider collected regional data as part of three extended missions in Lake Superior over the same periods. During the study, two significant storm events impacted the western end of Lake Superior; the first occurred during July 11-12, with 8-10 inches of rain in 24hrs, and the second on July 21 with winds in excess of 161 km/h. Using GIS software, we organized these diverse temporal data sets along a continuous time line with temporally coincident Modis Satellite data to visualize surface sediment plumes in relation to water quality measurements. Preliminary results suggest that both events impacted regional water quality, and that nearshore physical forces (upwelling and currents) influenced the spatial variability. Results comparing in situ measures with remotely sensed images will be discussed. not applicable

Visualization of pairwise and multilocus linkage disequilibrium structure using latent forests.

Directory of Open Access Journals (Sweden)

Raphaël Mourad

Full Text Available Linkage disequilibrium study represents a major issue in statistical genetics as it plays a fundamental role in gene mapping and helps us to learn more about human history. The linkage disequilibrium complex structure makes its exploratory data analysis essential yet challenging. Visualization methods, such as the triangular heat map implemented in Haploview, provide simple and useful tools to help understand complex genetic patterns, but remain insufficient to fully describe them. Probabilistic graphical models have been widely recognized as a powerful formalism allowing a concise and accurate modeling of dependences between variables. In this paper, we propose a method for short-range, long-range and chromosome-wide linkage disequilibrium visualization using forests of hierarchical latent class models. Thanks to its hierarchical nature, our method is shown to provide a compact view of both pairwise and multilocus linkage disequilibrium spatial structures for the geneticist. Besides, a multilocus linkage disequilibrium measure has been designed to evaluate linkage disequilibrium in hierarchy clusters. To learn the proposed model, a new scalable algorithm is presented. It constrains the dependence scope, relying on physical positions, and is able to deal with more than one hundred thousand single nucleotide polymorphisms. The proposed algorithm is fast and does not require phase genotypic data.

Linkage mechanisms in the vertebrate skull: Structure and function of three-dimensional, parallel transmission systems.

Science.gov (United States)

Olsen, Aaron M; Westneat, Mark W

2016-12-01

Many musculoskeletal systems, including the skulls of birds, fishes, and some lizards consist of interconnected chains of mobile skeletal elements, analogous to linkage mechanisms used in engineering. Biomechanical studies have applied linkage models to a diversity of musculoskeletal systems, with previous applications primarily focusing on two-dimensional linkage geometries, bilaterally symmetrical pairs of planar linkages, or single four-bar linkages. Here, we present new, three-dimensional (3D), parallel linkage models of the skulls of birds and fishes and use these models (available as free kinematic simulation software), to investigate structure-function relationships in these systems. This new computational framework provides an accessible and integrated workflow for exploring the evolution of structure and function in complex musculoskeletal systems. Linkage simulations show that kinematic transmission, although a suitable functional metric for linkages with single rotating input and output links, can give misleading results when applied to linkages with substantial translational components or multiple output links. To take into account both linear and rotational displacement we define force mechanical advantage for a linkage (analogous to lever mechanical advantage) and apply this metric to measure transmission efficiency in the bird cranial mechanism. For linkages with multiple, expanding output points we propose a new functional metric, expansion advantage, to measure expansion amplification and apply this metric to the buccal expansion mechanism in fishes. Using the bird cranial linkage model, we quantify the inaccuracies that result from simplifying a 3D geometry into two dimensions. We also show that by combining single-chain linkages into parallel linkages, more links can be simulated while decreasing or maintaining the same number of input parameters. This generalized framework for linkage simulation and analysis can accommodate linkages of differing

Comparing the Life Cycle Energy Consumption, Global Warming and Eutrophication Potentials of Several Water and Waste Service Options

Science.gov (United States)

Managing the water-energy-nutrient nexus for the built environment requires, in part, a full system analysis of energy consumption, global warming and eutrophication potentials of municipal water services. As an example, we evaluated the life cycle energy use, greenhouse gas (GHG...

STAKEHOLDER LINKAGES FOR SUSTAINABLE LAND ...

African Journals Online (AJOL)

Osondu

Key words: Stakeholders; farmer-expert linkages; resource management; Ethiopia. Introduction ... decentralized democratic decision making processes and thus ..... district offices within the given time limits. They were often .... -less willing and less ready to hearing weaker performance reports (expect more success with ...

Marine eutrophication impacts from present and future production of spring barley

DEFF Research Database (Denmark)

Cosme, Nuno Miguel Dias; Niero, Monia

2015-01-01

Environmental emissions of nitrogen (N) from agriculture surplus may enrich coastal waters and trigger marine eutrophication impacts. We estimated these impacts for spring barley production in Denmark, under present and future climatic conditions with double carbon dioxide concentration and 5 °C...... increase. Characterised emissions of airborne (NH3 and NOx) and waterborne (NO3-) forms result in an endpoint impact of 2.35*10-12 (North Sea) and 8.47*10-12 species.yr (Baltic Sea) under present conditions per kg spring barley produced. The future scenario shows 67% increase on both spatial units. Spatial...... to hypoxia under future pressures may alter the impacts assessment....

ANALISIS KEBIJAKAN LINKAGE PROGRAM LEMBAGA KEUANGAN SYARIAH DALAM RANGKA PEMBERDAYAAN UKM DI INDONESIA

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Siti Hamidah

2016-03-01

Linkage program adalah program yang menghubungkan bank dengan pelaku usaha mikro kecil melalui lembaga keuangan mikro. Kelemahan dalam Linkage program adalah pada aspek peraturan yang tersebar dalam berbagai aturan, dan khusus bagi lembaga keuangan syariah terdapat pula kendala berkaitan dengan kesesuaian dengan ketentuan syariah. Dari penelitian dengan pendekatan perundang-undangan dan pendekatan konseptual ini diperoleh inventarisasi serta analisis kebijakan Linkage Program bagi Lembaga Keuangan Syariah dalam hukum positif Indonesia. Kebijakan terkait Linkage program, diklasifikasi dalam 2 kelompok, yaitu kebijakan substansi dan prosedural. Aturan inilah yang menjadi rujukan bagi lembaga keuangan syariah rangka pemberdayaan usaha kecil mikro di Indonesia. Kata kunci: Linkage program, lembaga keuangan syariah, usaha mikro kecil

Electrostatic microactuators with integrated gear linkages for mechanical power transmission

NARCIS (Netherlands)

Legtenberg, R.; Legtenberg, Rob; Berenschot, Johan W.; Elwenspoek, Michael Curt; Fluitman, J.H.J.

1996-01-01

In this paper a surface micromachining process is presented which has been used to fabricate electrostatic microactuators that are interconnected with each other and linked to other movable microstructures by integrated gear linkages. The gear linkages consist of rotational and linear gear

Rapid colonisation of Lymnaea stagnalis by larval trematodes in eutrophic ponds in central Europe

Czech Academy of Sciences Publication Activity Database

Soldánová, Miroslava; Kostadinova, Aneta

2011-01-01

Roč. 41, č. 9 (2011), 981-990 ISSN 0020-7519 R&D Projects: GA ČR GAP505/10/1562; GA ČR GD206/09/H026; GA MŠk LC522 Institutional research plan: CEZ:AV0Z60220518 Keywords : Lymnaea stagnalis * Freshwater pulmonate snail * Larval trematodes * Colonisation and extinction * Competition-colonisation trade-off * Eutrophic ponds * Central Europe Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 3.393, year: 2011

Comparing the Life Cycle Energy Consumption, Global Warming and Eutrophication Potentials of Several Water and Waste Service Options

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Xiaobo Xue

2016-04-01

Full Text Available Managing the water-energy-nutrient nexus for the built environment requires, in part, a full system analysis of energy consumption, global warming and eutrophication potentials of municipal water services. As an example, we evaluated the life cycle energy use, greenhouse gas (GHG emissions and aqueous nutrient releases of the whole anthropogenic municipal water cycle starting from raw water extraction to wastewater treatment and reuse/discharge for five municipal water and wastewater systems. The assessed options included conventional centralized services and four alternative options following the principles of source-separation and water fit-for-purpose. The comparative life cycle assessment identified that centralized drinking water supply coupled with blackwater energy recovery and on-site greywater treatment and reuse was the most energy- and carbon-efficient water service system evaluated, while the conventional (drinking water and sewerage centralized system ranked as the most energy- and carbon-intensive system. The electricity generated from blackwater and food residuals co-digestion was estimated to offset at least 40% of life cycle energy consumption for water/waste services. The dry composting toilet option demonstrated the lowest life cycle eutrophication potential. The nutrients in wastewater effluent are the dominating contributors for the eutrophication potential for the assessed system configurations. Among the parameters for which variability and sensitivity were evaluated, the carbon intensity of the local electricity grid and the efficiency of electricity production by the co-digestion with the energy recovery process were the most important for determining the relative global warming potential results.

From fish to jellyfish in the eutrophicated Limfjorden (Denmark)

DEFF Research Database (Denmark)

Riisgård, Hans Ulrik; Andersen, Per; Hoffmann, Erik

2012-01-01

the historical development of nutrient overloading and subsequent oxygen depletion in near-bottom water, and how the annual landings of edible bottom-dwelling fish species (plaice, flounder, eel and others) caught in Limfjorden have decreased from about 2,500 t in the early 1920s to only about 20 t in recent...... ctenophore Mnemiopsis leidyi, which was observed in Limfjorden for the first time in 2007, is a second carnivore adding additional predation pressure of the indigenous A. aurita so that copepods and other mesozooplankton organisms may be virtually absent, as observed in 2008 and 2009 where ciliates made up...... a substantial part of the zooplankton biomass. Marine environmental management programmes should be aware of the increasing importance of both indigenous and new invasive jellyfish species that may show mass occurrence in especially eutrophicated and overfished areas...

Genomewide Linkage Screen for Waldenström Macroglobulinemia Susceptibility Loci in High-Risk Families

Science.gov (United States)

McMaster, Mary L.; Goldin, Lynn R.; Bai, Yan; Ter-Minassian, Monica; Boehringer, Stefan; Giambarresi, Therese R.; Vasquez, Linda G.; Tucker, Margaret A.

2006-01-01

Waldenström macroglobulinemia (WM), a distinctive subtype of non-Hodgkin lymphoma that features overproduction of immunoglobulin M (IgM), clearly has a familial component; however, no susceptibility genes have yet been identified. We performed a genomewide linkage analysis in 11 high-risk families with WM that were informative for linkage, for a total of 122 individuals with DNA samples, including 34 patients with WM and 10 patients with IgM monoclonal gammopathy of undetermined significance (IgM MGUS). We genotyped 1,058 microsatellite markers (average spacing 3.5 cM), performed both nonparametric and parametric linkage analysis, and computed both two-point and multipoint linkage statistics. The strongest evidence of linkage was found on chromosomes 1q and 4q when patients with WM and with IgM MGUS were both considered affected; nonparametric linkage scores were 2.5 (P=.0089) and 3.1 (P=.004), respectively. Other locations suggestive of linkage were found on chromosomes 3 and 6. Results of two-locus linkage analysis were consistent with independent effects. The findings from this first linkage analysis of families at high risk for WM represent important progress toward identifying gene(s) that modulate susceptibility to WM and toward understanding its complex etiology. PMID:16960805

Water organic pollution and eutrophication influence soil microbial processes, increasing soil respiration of estuarine wetlands: site study in jiuduansha wetland.

Science.gov (United States)

Zhang, Yue; Wang, Lei; Hu, Yu; Xi, Xuefei; Tang, Yushu; Chen, Jinhai; Fu, Xiaohua; Sun, Ying

2015-01-01

Undisturbed natural wetlands are important carbon sinks due to their low soil respiration. When compared with inland alpine wetlands, estuarine wetlands in densely populated areas are subjected to great pressure associated with environmental pollution. However, the effects of water pollution and eutrophication on soil respiration of estuarine and their mechanism have still not been thoroughly investigated. In this study, two representative zones of a tidal wetland located in the upstream and downstream were investigated to determine the effects of water organic pollution and eutrophication on soil respiration of estuarine wetlands and its mechanism. The results showed that eutrophication, which is a result of there being an excess of nutrients including nitrogen and phosphorus, and organic pollutants in the water near Shang shoal located upstream were higher than in downstream Xia shoal. Due to the absorption and interception function of shoals, there to be more nitrogen, phosphorus and organic matter in Shang shoal soil than in Xia shoal. Abundant nitrogen, phosphorus and organic carbon input to soil of Shang shoal promoted reproduction and growth of some highly heterotrophic metabolic microorganisms such as β-Proteobacteria, γ-Proteobacteria and Acidobacteria which is not conducive to carbon sequestration. These results imply that the performance of pollutant interception and purification function of estuarine wetlands may weaken their carbon sequestration function to some extent.

Parametric and nonparametric Granger causality testing: Linkages between international stock markets

Science.gov (United States)

De Gooijer, Jan G.; Sivarajasingham, Selliah

2008-04-01

This study investigates long-term linear and nonlinear causal linkages among eleven stock markets, six industrialized markets and five emerging markets of South-East Asia. We cover the period 1987-2006, taking into account the on-set of the Asian financial crisis of 1997. We first apply a test for the presence of general nonlinearity in vector time series. Substantial differences exist between the pre- and post-crisis period in terms of the total number of significant nonlinear relationships. We then examine both periods, using a new nonparametric test for Granger noncausality and the conventional parametric Granger noncausality test. One major finding is that the Asian stock markets have become more internationally integrated after the Asian financial crisis. An exception is the Sri Lankan market with almost no significant long-term linear and nonlinear causal linkages with other markets. To ensure that any causality is strictly nonlinear in nature, we also examine the nonlinear causal relationships of VAR filtered residuals and VAR filtered squared residuals for the post-crisis sample. We find quite a few remaining significant bi- and uni-directional causal nonlinear relationships in these series. Finally, after filtering the VAR-residuals with GARCH-BEKK models, we show that the nonparametric test statistics are substantially smaller in both magnitude and statistical significance than those before filtering. This indicates that nonlinear causality can, to a large extent, be explained by simple volatility effects.

Viral linkage in HIV-1 seroconverters and their partners in an HIV-1 prevention clinical trial.

Directory of Open Access Journals (Sweden)

Mary S Campbell

2011-03-01

Full Text Available Characterization of viruses in HIV-1 transmission pairs will help identify biological determinants of infectiousness and evaluate candidate interventions to reduce transmission. Although HIV-1 sequencing is frequently used to substantiate linkage between newly HIV-1 infected individuals and their sexual partners in epidemiologic and forensic studies, viral sequencing is seldom applied in HIV-1 prevention trials. The Partners in Prevention HSV/HIV Transmission Study (ClinicalTrials.gov #NCT00194519 was a prospective randomized placebo-controlled trial that enrolled serodiscordant heterosexual couples to determine the efficacy of genital herpes suppression in reducing HIV-1 transmission; as part of the study analysis, HIV-1 sequences were examined for genetic linkage between seroconverters and their enrolled partners.We obtained partial consensus HIV-1 env and gag sequences from blood plasma for 151 transmission pairs and performed deep sequencing of env in some cases. We analyzed sequences with phylogenetic techniques and developed a Bayesian algorithm to evaluate the probability of linkage. For linkage, we required monophyletic clustering between enrolled partners' sequences and a Bayesian posterior probability of ≥ 50%. Adjudicators classified each seroconversion, finding 108 (71.5% linked, 40 (26.5% unlinked, and 3 (2.0% indeterminate transmissions, with linkage determined by consensus env sequencing in 91 (84%. Male seroconverters had a higher frequency of unlinked transmissions than female seroconverters. The likelihood of transmission from the enrolled partner was related to time on study, with increasing numbers of unlinked transmissions occurring after longer observation periods. Finally, baseline viral load was found to be significantly higher among linked transmitters.In this first use of HIV-1 sequencing to establish endpoints in a large clinical trial, more than one-fourth of transmissions were unlinked to the enrolled partner

Cyanobacterial carbon concentrating mechanisms facilitate sustained CO2 depletion in eutrophic lakes

Science.gov (United States)

Morales-Williams, Ana M.; Wanamaker, Alan D., Jr.; Downing, John A.

2017-06-01

Phytoplankton blooms are increasing in frequency, intensity, and duration in aquatic ecosystems worldwide. In many eutrophic lakes, these high levels of primary productivity correspond to periods of CO2 depletion in surface waters. Cyanobacteria and other groups of phytoplankton have the ability to actively transport bicarbonate (HCO3-) across their cell membrane when CO2 concentrations are limiting, possibly giving them a competitive advantage over algae not using carbon concentrating mechanisms (CCMs). To investigate whether CCMs can maintain phytoplankton bloom biomass under CO2 depletion, we measured the δ13C signatures of dissolved inorganic carbon (δ13CDIC) and phytoplankton particulate organic carbon (δ13Cphyto) in 16 mesotrophic to hypereutrophic lakes during the ice-free season of 2012. We used mass-balance relationships to determine the dominant inorganic carbon species used by phytoplankton under CO2 stress. We found a significant positive relationship between phytoplankton biomass and phytoplankton δ13C signatures as well as a significant nonlinear negative relationship between water column ρCO2 and isotopic composition of phytoplankton, indicating a shift from diffusive uptake to active uptake by phytoplankton of CO2 or HCO3- during blooms. Calculated photosynthetic fractionation factors indicated that this shift occurs specifically when surface water CO2 drops below atmospheric equilibrium. Our results indicate that active HCO3- uptake via CCMs may be an important mechanism in maintaining phytoplankton blooms when CO2 is depleted. Further increases in anthropogenic pressure, eutrophication, and cyanobacteria blooms are therefore expected to contribute to increased bicarbonate uptake to sustain primary production.

Cyanobacterial carbon concentrating mechanisms facilitate sustained CO2 depletion in eutrophic lakes

Directory of Open Access Journals (Sweden)

A. M. Morales-Williams

2017-06-01

Full Text Available Phytoplankton blooms are increasing in frequency, intensity, and duration in aquatic ecosystems worldwide. In many eutrophic lakes, these high levels of primary productivity correspond to periods of CO2 depletion in surface waters. Cyanobacteria and other groups of phytoplankton have the ability to actively transport bicarbonate (HCO3− across their cell membrane when CO2 concentrations are limiting, possibly giving them a competitive advantage over algae not using carbon concentrating mechanisms (CCMs. To investigate whether CCMs can maintain phytoplankton bloom biomass under CO2 depletion, we measured the δ13C signatures of dissolved inorganic carbon (δ13CDIC and phytoplankton particulate organic carbon (δ13Cphyto in 16 mesotrophic to hypereutrophic lakes during the ice-free season of 2012. We used mass–balance relationships to determine the dominant inorganic carbon species used by phytoplankton under CO2 stress. We found a significant positive relationship between phytoplankton biomass and phytoplankton δ13C signatures as well as a significant nonlinear negative relationship between water column ρCO2 and isotopic composition of phytoplankton, indicating a shift from diffusive uptake to active uptake by phytoplankton of CO2 or HCO3− during blooms. Calculated photosynthetic fractionation factors indicated that this shift occurs specifically when surface water CO2 drops below atmospheric equilibrium. Our results indicate that active HCO3− uptake via CCMs may be an important mechanism in maintaining phytoplankton blooms when CO2 is depleted. Further increases in anthropogenic pressure, eutrophication, and cyanobacteria blooms are therefore expected to contribute to increased bicarbonate uptake to sustain primary production.

Heritability and whole genome linkage of pulse pressure in Chinese twin pairs

DEFF Research Database (Denmark)

Jiang, Wengjie; Zhang, Dongfeng; Pang, Zengchang

2012-01-01

with a heritability estimate of 0.45. Genome-wide non-parametric linkage analysis identified three significant linkage peaks on chromosome 11 (lod score 4.06 at 30.5 cM), chromosome 12 (lod score 3.97 at 100.7 cM), and chromosome 18 (lod score 4.01 at 70.7 cM) with the last two peaks closely overlapping with linkage...

EDITORIAL Development Linkages between Tree Breeding ...

African Journals Online (AJOL)

EDITORIAL Development Linkages between Tree Breeding Programmes and National/Regional Tree Seed Centres in Africa. ... Discovery and Innovation. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives.

Entrepreneurship And Business Management - Exploring Linkages For Sustainable Development

Directory of Open Access Journals (Sweden)

Dr Serah K Mbetwa

2015-08-01

Full Text Available Entrepreneurs have emerged as market leaders in todays business world amidst the numerous economic turmoil constantly affecting economies on a global scale. This research paper is on entrepreneurship and business management and its linkages to other business stakeholders. The research paper therefore discusses entrepreneurship and business management exploring the linkages to available financing and potential institutions for startup capital by linking entrepreneurs to the government financiers and the public clientele. It is believed that this can bring about achievement of sustainable development goals translating into sustainable development and hence economic growth. The idea of funding is echoed by Robert Rice 2016 An entrepreneur without funding is like a musician with no instruments. Sustainability and entrepreneurship sustainopreneurship is made possible with availability of information on linkages between entrepreneurs and financial lending institutions as well as government policy. It is hoped that the research will add to the existing knowledge and help entrepreneurs with funding options for their business ideas to come to life. Findings show that the government financial lending institutions and the public are the major linkages between entrepreneurship and business management and are critical for attaining sustainable development goals and achieving economic growth.

Phytoremediation to remove nutrients and improve eutrophic stormwaters using water lettuce (Pistia stratiotes L.).

Science.gov (United States)

Lu, Qin; He, Zhenli L; Graetz, Donald A; Stoffella, Peter J; Yang, Xiaoe

2010-01-01

Water quality impairment by nutrient enrichment from agricultural activities has been a concern worldwide. Phytoremediation technology using aquatic plants in constructed wetlands and stormwater detention ponds is increasingly applied to remediate eutrophic waters. The objectives of this study were to evaluate the effectiveness and potential of water lettuce (Pistia stratiotes L.) in removing nutrients including nitrogen (N) and phosphorus (P) from stormwater in the constructed water detention systems before it is discharged into the St. Lucie Estuary, an important surface water system in Florida, using phytoremediation technologies. In this study, water lettuce (P. stratiotes) was planted in the treatment plots of two stormwater detention ponds (East and West Ponds) in 2005-2007 and water samples from both treatment and control plots were weekly collected and analyzed for water quality properties including pH, electrical conductivity, turbidity, suspended solids, and nutrients (N and P). Optimum plant density was maintained and plant samples were collected monthly and analyzed for nutrient contents. Water quality in both ponds was improved, as evidenced by decreases in water turbidity, suspended solids, and nutrient concentrations. Water turbidity was decreased by more than 60%. Inorganic N (NH(4) (+) and NO(3) (-)) concentrations in treatment plots were more than 50% lower than those in control plots (without plant). Reductions in both PO(4) (3-) and total P were approximately 14-31%, as compared to the control plots. Water lettuce contained average N and P concentrations of 17 and 3.0 g kg(-1), respectively, and removed 190-329 kg N ha(-1) and 25-34 kg P ha(-1) annually. Many aquatic plants have been used to remove nutrients from eutrophic waters but water lettuce proved superior to most other plants in nutrient removal efficiency, owing to its rapid growth and high biomass yield potential. However, the growth and nutrient removal potential are affected by many

Nance-Horan syndrome: linkage analysis in a family from The Netherlands.

Science.gov (United States)

Bergen, A A; ten Brink, J; Schuurman, E J; Bleeker-Wagemakers, E M

1994-05-01

Linkage analysis was carried out in a Dutch family with Nance-Horan (NH) syndrome. Close linkage without recombination between NH and the Xp loci DXS207, DXS43, and DXS365 (zmax = 3.23) was observed. Multipoint linkage analysis and the analysis of recombinations in multiple informative meioses suggest the genetic order Xcen-DMD (exon 49)-DXS451-(NH, DXS207, DXS365, DXS43)-(STS, DXF30)-Xpter. These data refine the localization of the NH locus on the distal Xp.

Size-mass relationships of Melanoides tuberculatus (Thiaridae: Gastropoda in a eutrophic reservoir

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Eduardo Carvalho Silva

2010-10-01

Full Text Available This study evaluated the relationships of certain allometric measurements in Melanoides tuberculatus Muller, 1774, in order to develop a statistical model to estimate the biomass of this mollusc species. We measured the total length and aperture of 70 shells. These measurements were correlated with the biomass values to construct exponential and power-function models, and both models showed high coefficients of determination. The exponential model was the better biomass predictor, with a coefficient of determination over 93%. These proposed models may be an effective tool to determine the biomass of M. tuberculatus in eutrophic Brazilian reservoirs.

A genetic linkage map of hexaploid naked oat constructed with SSR markers

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Gaoyuan Song

2015-08-01

Full Text Available Naked oat is a unique health food crop in China. Using 202 F2 individuals derived from a hybrid between the variety 578 and the landrace Sanfensan, we constructed a genetic linkage map consisting of 22 linkage groups covering 2070.50 cM and including 208 simple sequence repeat (SSR markers. The minimum distance between adjacent markers was 0.01 cM and the average was 9.95 cM. Each linkage group contained 2–22 markers. The largest linkage group covered 174.40 cM and the shortest one covered 36.80 cM, with an average of 94.11 cM. Thirty-six markers (17.3% showing distorted segregation were distributed across linkage groups LG5 to LG22. This map complements published oat genetic maps and is applicable for quantitative trait locus analysis, gene cloning and molecular marker-assisted selection.

Meta-analysis of 32 genome-wide linkage studies of schizophrenia

Science.gov (United States)

Ng, MYM; Levinson, DF; Faraone, SV; Suarez, BK; DeLisi, LE; Arinami, T; Riley, B; Paunio, T; Pulver, AE; Irmansyah; Holmans, PA; Escamilla, M; Wildenauer, DB; Williams, NM; Laurent, C; Mowry, BJ; Brzustowicz, LM; Maziade, M; Sklar, P; Garver, DL; Abecasis, GR; Lerer, B; Fallin, MD; Gurling, HMD; Gejman, PV; Lindholm, E; Moises, HW; Byerley, W; Wijsman, EM; Forabosco, P; Tsuang, MT; Hwu, H-G; Okazaki, Y; Kendler, KS; Wormley, B; Fanous, A; Walsh, D; O’Neill, FA; Peltonen, L; Nestadt, G; Lasseter, VK; Liang, KY; Papadimitriou, GM; Dikeos, DG; Schwab, SG; Owen, MJ; O’Donovan, MC; Norton, N; Hare, E; Raventos, H; Nicolini, H; Albus, M; Maier, W; Nimgaonkar, VL; Terenius, L; Mallet, J; Jay, M; Godard, S; Nertney, D; Alexander, M; Crowe, RR; Silverman, JM; Bassett, AS; Roy, M-A; Mérette, C; Pato, CN; Pato, MT; Roos, J Louw; Kohn, Y; Amann-Zalcenstein, D; Kalsi, G; McQuillin, A; Curtis, D; Brynjolfson, J; Sigmundsson, T; Petursson, H; Sanders, AR; Duan, J; Jazin, E; Myles-Worsley, M; Karayiorgou, M; Lewis, CM

2009-01-01

A genome scan meta-analysis (GSMA) was carried out on 32 independent genome-wide linkage scan analyses that included 3255 pedigrees with 7413 genotyped cases affected with schizophrenia (SCZ) or related disorders. The primary GSMA divided the autosomes into 120 bins, rank-ordered the bins within each study according to the most positive linkage result in each bin, summed these ranks (weighted for study size) for each bin across studies and determined the empirical probability of a given summed rank (PSR) by simulation. Suggestive evidence for linkage was observed in two single bins, on chromosomes 5q (142-168 Mb) and 2q (103-134 Mb). Genome-wide evidence for linkage was detected on chromosome 2q (119-152 Mb) when bin boundaries were shifted to the middle of the previous bins. The primary analysis met empirical criteria for ‘aggregate’ genome-wide significance, indicating that some or all of 10 bins are likely to contain loci linked to SCZ, including regions of chromosomes 1, 2q, 3q, 4q, 5q, 8p and 10q. In a secondary analysis of 22 studies of European-ancestry samples, suggestive evidence for linkage was observed on chromosome 8p (16-33 Mb). Although the newer genome-wide association methodology has greater power to detect weak associations to single common DNA sequence variants, linkage analysis can detect diverse genetic effects that segregate in families, including multiple rare variants within one locus or several weakly associated loci in the same region. Therefore, the regions supported by this meta-analysis deserve close attention in future studies. PMID:19349958

Acclimation of Hydrilla verticillata to sediment anoxia in vegetation restoration in eutrophic waters.

Science.gov (United States)

Wu, Juan; Dai, Yanran; Rui, Shengyang; Cui, Naxin; Zhong, Fei; Cheng, Shuiping

2015-12-01

Sediment anoxia generally results from intense organic enrichment and is a limiting factor in the restoration of vegetation in eutrophic waters. To investigate the effect of sediment anoxia on a typical pollution-tolerant submerged macrophyte species, Hydrilla verticillata, and acclimation mechanisms in the plant, a gradient of sediment anoxia was simulated with additions of sucrose to the sediment, which can stimulate increased concentrations of total nitrogen, NH4(+) and Fe in pore water. H. verticillata growth was significantly affected by highly anoxic conditions, as indicated by reduced total biomass in the 0.5 and 1% sucrose treatments. However, slight anoxia (0.1% sucrose addition) promoted growth, and the shoot biomass was 22.64% higher than in the control. In addition to morphologic alterations, H. verticillata showed physiological acclimations to anoxia, including increased anaerobic respiration and changes in carbon and nitrogen metabolism in roots. The soluble protein and soluble carbohydrate contents in roots of the 1% treatment were both significantly higher compared with those in the control. The increase in alcohol dehydrogenase activity and pyruvate content in the roots suggested that H. verticillata has a well-developed capacity for anaerobic fermentation. This study suggests that highly anoxic sediments inhibit the growth of H. verticillata and the species has a degree of tolerance to anoxic conditions. Further in situ investigations should be conducted on the interactions between sediment conditions and macrophytes to comprehensively evaluate the roles of sediment in the restoration of vegetation in eutrophic waters.

Factors That Influence Linkages to HIV Continuum of Care Services: Implications for Multi-Level Interventions

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Rogério M. Pinto

2017-11-01

Full Text Available Worldwide, the human immunodeficiency virus (HIV continuum of care involves health promotion providers (e.g., social workers and health educators linking patients to medical personnel who provide HIV testing, primary care, and antiretroviral treatments. Regrettably, these life-saving linkages are not always made consistently and many patients are not retained in care. To design, test and implement effective interventions, we need to first identify key factors that may improve linkage-making. To help close this gap, we used in-depth interviews with 20 providers selected from a sample of 250 participants in a mixed-method longitudinal study conducted in New York City (2012–2017 in order to examine the implementation of HIV services for at-risk populations. Following a sociomedical framework, we identified provider-, interpersonal- and environmental-level factors that influence how providers engage patients in the care continuum by linking them to HIV testing, HIV care, and other support services. These factors occurred in four domains of reference: Providers’ Professional Knowledge Base; Providers’ Interprofessional Collaboration; Providers’ Work-Related Changes; and Best Practices in a Competitive Environment. Of particular importance, our findings show that a competitive environment and a fear of losing patients to other agencies may inhibit providers from engaging in linkage-making. Our results suggest relationships between factors within and across all four domains; we recommend interventions to modify factors in all domains for maximum effect toward improving care continuum linkage-making. Our findings may be applicable in different areas of the globe with high HIV prevalence.

Radial oxygen loss from roots of Vallisneria spiralis L.: biogeochemical implications in eutrophic aquatic ecosystems

OpenAIRE

Soana, Elisa

2013-01-01

Eutrophication and the accumulation of organic matter have been addressed as the major factors determining the decline of benthic vegetation in impacted water bodies and the consequent loss of key ecosystemic functions. In freshwater environments the literature reports submersed macrophyte die-back events and the switch to free-floating and floating-leaved plants dominated states. Species-specific differences in macrophyte response along organic gradients are evident. Some species have develo...

Accuracy of computer-aided ultrasound as compared with magnetic resonance imaging in the evaluation of nonalcoholic fatty liver disease in obese and eutrophic adolescents

Energy Technology Data Exchange (ETDEWEB)

Nascimento, Jose Hermes Ribas do, E-mail: josehermesnascimento@gmail.com [Instituto Cenecista de Ensino Superior de Santo Angelo (IESA), Santo Angelo, RS (Brazil); Soder, Ricardo Bernardi; Epifanio, Matias; Baldisserotto, Matteo [Pontificia Universidade Catolica do Rio Grande do Sul (InsCer/PUCRS), Porto Alegre, RS (Brazil). Instituto do Cerebro

2015-07-15

Objective: to compare the accuracy of computer-aided ultrasound (US) and magnetic resonance imaging (MRI) by means of hepatorenal gradient analysis in the evaluation of nonalcoholic fatty liver disease (NAFLD) in adolescents. Materials and methods: this prospective, cross-sectional study evaluated 50 adolescents (aged 11-17 years), including 24 obese and 26 eutrophic individuals. All adolescents underwent computer-aided US, MRI, laboratory tests, and anthropometric evaluation. Sensitivity, specificity, positive and negative predictive values and accuracy were evaluated for both imaging methods, with subsequent generation of the receiver operating characteristic (ROC) curve and calculation of the area under the ROC curve to determine the most appropriate cutoff point for the hepatorenal gradient in order to predict the degree of steatosis, utilizing MRI results as the gold-standard. Results: the obese group included 29.2% girls and 70.8% boys, and the eutrophic group, 69.2% girls and 30.8% boys. The prevalence of NAFLD corresponded to 19.2% for the eutrophic group and 83% for the obese group. The ROC curve generated for the hepatorenal gradient with a cutoff point of 13 presented 100% sensitivity and 100% specificity. As the same cutoff point was considered for the eutrophic group, false-positive results were observed in 9.5% of cases (90.5% specificity) and false-negative results in 0% (100% sensitivity). Conclusion: computer-aided US with hepatorenal gradient calculation is a simple and noninvasive technique for semiquantitative evaluation of hepatic echogenicity and could be useful in the follow-up of adolescents with NAFLD, population screening for this disease as well as for clinical studies. (author)

Accuracy of computer-aided ultrasound as compared with magnetic resonance imaging in the evaluation of nonalcoholic fatty liver disease in obese and eutrophic adolescents

International Nuclear Information System (INIS)

Nascimento, Jose Hermes Ribas do; Soder, Ricardo Bernardi; Epifanio, Matias; Baldisserotto, Matteo

2015-01-01

Objective: to compare the accuracy of computer-aided ultrasound (US) and magnetic resonance imaging (MRI) by means of hepatorenal gradient analysis in the evaluation of nonalcoholic fatty liver disease (NAFLD) in adolescents. Materials and methods: this prospective, cross-sectional study evaluated 50 adolescents (aged 11-17 years), including 24 obese and 26 eutrophic individuals. All adolescents underwent computer-aided US, MRI, laboratory tests, and anthropometric evaluation. Sensitivity, specificity, positive and negative predictive values and accuracy were evaluated for both imaging methods, with subsequent generation of the receiver operating characteristic (ROC) curve and calculation of the area under the ROC curve to determine the most appropriate cutoff point for the hepatorenal gradient in order to predict the degree of steatosis, utilizing MRI results as the gold-standard. Results: the obese group included 29.2% girls and 70.8% boys, and the eutrophic group, 69.2% girls and 30.8% boys. The prevalence of NAFLD corresponded to 19.2% for the eutrophic group and 83% for the obese group. The ROC curve generated for the hepatorenal gradient with a cutoff point of 13 presented 100% sensitivity and 100% specificity. As the same cutoff point was considered for the eutrophic group, false-positive results were observed in 9.5% of cases (90.5% specificity) and false-negative results in 0% (100% sensitivity). Conclusion: computer-aided US with hepatorenal gradient calculation is a simple and noninvasive technique for semiquantitative evaluation of hepatic echogenicity and could be useful in the follow-up of adolescents with NAFLD, population screening for this disease as well as for clinical studies. (author)

Robust LOD scores for variance component-based linkage analysis.

Science.gov (United States)

Blangero, J; Williams, J T; Almasy, L

2000-01-01

The variance component method is now widely used for linkage analysis of quantitative traits. Although this approach offers many advantages, the importance of the underlying assumption of multivariate normality of the trait distribution within pedigrees has not been studied extensively. Simulation studies have shown that traits with leptokurtic distributions yield linkage test statistics that exhibit excessive Type I error when analyzed naively. We derive analytical formulae relating the deviation from the expected asymptotic distribution of the lod score to the kurtosis and total heritability of the quantitative trait. A simple correction constant yields a robust lod score for any deviation from normality and for any pedigree structure, and effectively eliminates the problem of inflated Type I error due to misspecification of the underlying probability model in variance component-based linkage analysis.

Search for linkage to schizophrenia on the X and Y chromosomes

Energy Technology Data Exchange (ETDEWEB)

Devoto, M.; Ott, J. [Columbia Univ., New York, NY (United States); Vita, A. [Univ. of Milan (Italy)] [and others

1994-06-15

Markers for X chromosome loci were used in linkage studies of a large group of small families (n = 126) with at least two schizophrenic members in one sibship. Based on the hypothesis that a gene for schizophrenia could be X-Y linked, with homologous loci on both X and Y, our analyses included all families regardless of the pattern of familial inheritance. Lod scores were computed with both standard X-linked and a novel X-Y model, and sib-pair analyses were performed for all markers examining the sharing of maternal alleles. Small positive lod scores were obtained for loci pericentromeric, from Xp11.4 to Xq12. Lod scores were also computed separately in families selected for evidence of maternal inheritance and absence of male to male transmission of psychosis. The lod scores for linkage to the locus DXS7 reached a maximum of 1.83 at 0.08% recombination, assuming dominant inheritance on the X chromosome in these families (n = 34). Further investigation of the X-Y homologous gene hypothesis focussing on this region is warranted. 39 refs. 1 fig., 6 tabs.

Linkage of biomolecules to solid phases for immunoassay

International Nuclear Information System (INIS)

Chapman, R.S.

1998-01-01

Topics covered by this lecture include a brief review of the principal methods of linkage of biomolecules to solid phase matrices. Copies of the key self explanatory slides are presented as figures together with reprints of two publications by the author dealing with a preferred chemistry for the covalent linkage of antibodies to hydroxyl and amino functional groups and the effects of changes in solid phase matrix and antibody coupling chemistry on the performance of a typical excess reagent immunoassay for thyroid stimulating hormone

In situ effects of simulated overfishing and eutrophication on settlement of benthic coral reef invertebrates in the Central Red Sea.

KAUST Repository

Jessen, Christian; Voolstra, Christian R.; Wild, Christian

2014-01-01

overfishing through predator/grazer exclusion and simulated eutrophication through fertilizer addition on settlement of reef associated invertebrates on light-exposed and -shaded tiles over 4 months. At the end of the study period invertebrates had almost

Preliminary genetic linkage map of the abalone Haliotis diversicolor Reeve

Science.gov (United States)

Shi, Yaohua; Guo, Ximing; Gu, Zhifeng; Wang, Aimin; Wang, Yan

2010-05-01

Haliotis diversicolor Reeve is one of the most important mollusks cultured in South China. Preliminary genetic linkage maps were constructed with amplified fragment length polymorphism (AFLP) markers. A total of 2 596 AFLP markers were obtained from 28 primer combinations in two parents and 78 offsprings. Among them, 412 markers (15.9%) were polymorphic and segregated in the mapping family. Chi-square tests showed that 151 (84.4%) markers segregated according to the expected 1:1 Mendelian ratio ( P<0.05) in the female parent, and 200 (85.8%) in the male parent. For the female map, 179 markers were used for linkage analysis and 90 markers were assigned to 17 linkage groups with an average interval length of 25.7 cm. For the male map, 233 markers were used and 94 were mapped into 18 linkage groups, with an average interval of 25.0 cm. The estimated genome length was 2 773.0 cm for the female and 2 817.1 cm for the male map. The observed length of the linkage map was 1 875.2 cm and 1 896.5 cm for the female and male maps, respectively. When doublets were considered, the map length increased to 2 152.8 cm for the female and 2 032.7 cm for the male map, corresponding to genome coverage of 77.6% and 72.2%, respectively.

Clinical and linkage study of a large family with simple ectopia lentis linked to FBN1

Energy Technology Data Exchange (ETDEWEB)

Edwards, M.J.; Roberts, J.; Partington, M.W. [Newcastle and Northern New South Wales Genetics Service (Australia); Colley, P.W. [John Hunter Hospital, Newcastle (Australia); Hollway, G.E.; Kozman, H.M.; Mulley, J.C. [Adelaide Children`s Hospital, North Adelaide (Australia)

1994-10-15

Simple ectopia lentis (EL) was studied in a large family, by clinical examination and analysis of linkage to markers in the region of FBN1, the gene for fibrillin which causes Marfan syndrome on chromosome 15. No patient had clinical or echocardiographic evidence of Marfan syndrome, although there was a trend towards relatively longer measurements of height; lower segment; arm span; middle finger, hand, and foot length in the affected members of the family, compared with unaffected sibs of the same sex. Analysis of linkage to intragenic FBN1 markers was inconclusive because they were relatively uninformative. Construction of a multipoint background map from the CEPH reference families identified microsatellite markers linked closely to FBN1 which could demonstrate linkage of EL in this family to the FBN1 region. LINKMAP analysis detected a multipoint lod score of 5.68 at D15S119, a marker approximately 6 cM distal to FBN1, and a multipoint lod score of 5.04 at FBN1. The EL gene in this family is likely to be allelic to Marfan syndrome, and molecular characterization of the FBN1 mutation should now be possible. 25 refs., 6 figs., 2 tabs.

Eutrophication Modeling Using Variable Chlorophyll Approach

International Nuclear Information System (INIS)

Abdolabadi, H.; Sarang, A.; Ardestani, M.; Mahjoobi, E.

2016-01-01

In this study, eutrophication was investigated in Lake Ontario to identify the interactions among effective drivers. The complexity of such phenomenon was modeled using a system dynamics approach based on a consideration of constant and variable stoichiometric ratios. The system dynamics approach is a powerful tool for developing object-oriented models to simulate complex phenomena that involve feedback effects. Utilizing stoichiometric ratios is a method for converting the concentrations of state variables. During the physical segmentation of the model, Lake Ontario was divided into two layers, i.e., the epilimnion and hypolimnion, and differential equations were developed for each layer. The model structure included 16 state variables related to phytoplankton, herbivorous zooplankton, carnivorous zooplankton, ammonium, nitrate, dissolved phosphorus, and particulate and dissolved carbon in the epilimnion and hypolimnion during a time horizon of one year. The results of several tests to verify the model, close to 1 Nash-Sutcliff coefficient (0.98), the data correlation coefficient (0.98), and lower standard errors (0.96), have indicated well-suited model’s efficiency. The results revealed that there were significant differences in the concentrations of the state variables in constant and variable stoichiometry simulations. Consequently, the consideration of variable stoichiometric ratios in algae and nutrient concentration simulations may be applied in future modeling studies to enhance the accuracy of the results and reduce the likelihood of inefficient control policies.

Multivariate analysis of anxiety disorders yields further evidence of linkage to chromosomes 4q21 and 7p in panic disorder families.

Science.gov (United States)

Logue, Mark W; Bauver, Sarah R; Knowles, James A; Gameroff, Marc J; Weissman, Myrna M; Crowe, Raymond R; Fyer, Abby J; Hamilton, Steven P

2012-04-01

Replication has been difficult to achieve in linkage studies of psychiatric disease. Linkage studies of panic disorder have indicated regions of interest on chromosomes 1q, 2p, 2q, 3, 7, 9, 11, 12q13, 12q23, and 15. Few regions have been implicated in more than one study. We examine two samples, the Iowa (IA) and the Columba panic disorder families. We use the fuzzy-clustering method presented by Kaabi et al. [Kaabi et al. (2006); Am J Hum Genet 78: 543-553] to summarize liability to panic disorder, agoraphobia, simple phobia, and social phobia. Kaabi et al. applied this method to the Yale panic disorder linkage families and found evidence of linkage to chromosomes 4q21, 4q32, 7p, and 8. When we apply the same method to the IA families, we obtain overlapping evidence of linkage to chromosomes 4q21 and 7p. Additionally, we find evidence of linkage on chromosomes 1, 5, 6, 16, and 22. The Columbia (CO) data does not indicate linkage to any of the Kaabi et al. peaks, instead implicating chromosomes 2 and 22q11 (2 Mb from COMT). There is some evidence of overlapping linkage between the IA and CO datasets on chromosomes 1 and 14. While use of fuzzy clustering has not produced complete concordance across datasets, it has produced more than previously seen in analyses of panic disorder proper. We conclude that chromosomes 4q21 and 7p should be considered strong candidate regions for panic and fear-associated anxiety disorder loci. More generally, this suggests that analyses including multiple aspects of psychopathology may lead to greater consistency across datasets. Copyright © 2012 Wiley Periodicals, Inc.

Short term effects of two experimantal eutrophication on carbon and nitrogen cycling in two types of wet grassland

Czech Academy of Sciences Publication Activity Database

Picek, T.; Kaštovská, E.; Edwards, K.; Zemanová, K.; Dušek, Jiří

9 /suppl./, - (2008), s. 1-8 ISSN 1585-8553 R&D Projects: GA ČR(CZ) GA526/06/0276 Institutional research plan: CEZ:AV0Z60870520 Keywords : Carbon * Eutrophication * Gas emissions * Microbial processes * Nitrogen * Wet meadows Subject RIV: EH - Ecology, Behaviour Impact factor: 0.898, year: 2008

A Simple Sampling Method for Estimating the Accuracy of Large Scale Record Linkage Projects.

Science.gov (United States)

Boyd, James H; Guiver, Tenniel; Randall, Sean M; Ferrante, Anna M; Semmens, James B; Anderson, Phil; Dickinson, Teresa

2016-05-17

Record linkage techniques allow different data collections to be brought together to provide a wider picture of the health status of individuals. Ensuring high linkage quality is important to guarantee the quality and integrity of research. Current methods for measuring linkage quality typically focus on precision (the proportion of incorrect links), given the difficulty of measuring the proportion of false negatives. The aim of this work is to introduce and evaluate a sampling based method to estimate both precision and recall following record linkage. In the sampling based method, record-pairs from each threshold (including those below the identified cut-off for acceptance) are sampled and clerically reviewed. These results are then applied to the entire set of record-pairs, providing estimates of false positives and false negatives. This method was evaluated on a synthetically generated dataset, where the true match status (which records belonged to the same person) was known. The sampled estimates of linkage quality were relatively close to actual linkage quality metrics calculated for the whole synthetic dataset. The precision and recall measures for seven reviewers were very consistent with little variation in the clerical assessment results (overall agreement using the Fleiss Kappa statistics was 0.601). This method presents as a possible means of accurately estimating matching quality and refining linkages in population level linkage studies. The sampling approach is especially important for large project linkages where the number of record pairs produced may be very large often running into millions.

Hereditary spastic paraplegia: LOD-score considerations for confirmation of linkage in a heterogeneous trait

Energy Technology Data Exchange (ETDEWEB)

Dube, M.P.; Kibar, Z.; Rouleau, G.A. [McGill Univ., Quebec (Canada)] [and others

1997-03-01

Hereditary spastic paraplegia (HSP) is a degenerative disorder of the motor system, defined by progressive weakness and spasticity of the lower limbs. HSP may be inherited as an autosomal dominant (AD), autosomal recessive, or an X-linked trait. AD HSP is genetically heterogeneous, and three loci have been identified so far: SPG3 maps to chromosome 14q, SPG4 to 2p, and SPG4a to 15q. We have undertaken linkage analysis with 21 uncomplicated AD families to the three AD HSP loci. We report significant linkage for three of our families to the SPG4 locus and exclude several families by multipoint linkage. We used linkage information from several different research teams to evaluate the statistical probability of linkage to the SPG4 locus for uncomplicated AD HSP families and established the critical LOD-score value necessary for confirmation of linkage to the SPG4 locus from Bayesian statistics. In addition, we calculated the empirical P-values for the LOD scores obtained with all families with computer simulation methods. Power to detect significant linkage, as well as type I error probabilities, were evaluated. This combined analytical approach permitted conclusive linkage analyses on small to medium-size families, under the restrictions of genetic heterogeneity. 19 refs., 1 fig., 1 tab.

Hereditary spastic paraplegia: LOD-score considerations for confirmation of linkage in a heterogeneous trait.

Science.gov (United States)

Dubé, M P; Mlodzienski, M A; Kibar, Z; Farlow, M R; Ebers, G; Harper, P; Kolodny, E H; Rouleau, G A; Figlewicz, D A

1997-03-01

Hereditary spastic paraplegia (HSP) is a degenerative disorder of the motor system, defined by progressive weakness and spasticity of the lower limbs. HSP may be inherited as an autosomal dominant (AD), autosomal recessive, or an X-linked trait. AD HSP is genetically heterogeneous, and three loci have been identified so far: SPG3 maps to chromosome 14q, SPG4 to 2p, and SPG4a to 15q. We have undertaken linkage analysis with 21 uncomplicated AD families to the three AD HSP loci. We report significant linkage for three of our families to the SPG4 locus and exclude several families by multipoint linkage. We used linkage information from several different research teams to evaluate the statistical probability of linkage to the SPG4 locus for uncomplicated AD HSP families and established the critical LOD-score value necessary for confirmation of linkage to the SPG4 locus from Bayesian statistics. In addition, we calculated the empirical P-values for the LOD scores obtained with all families with computer simulation methods. Power to detect significant linkage, as well as type I error probabilities, were evaluated. This combined analytical approach permitted conclusive linkage analyses on small to medium-size families, under the restrictions of genetic heterogeneity.

Fungal Diversity of Human Gut Microbiota Among Eutrophic, Overweight, and Obese Individuals Based on Aerobic Culture-Dependent Approach.

Science.gov (United States)

Borges, Francis M; de Paula, Thaís O; Sarmiento, Marjorie R A; de Oliveira, Maycon G; Pereira, Maria L M; Toledo, Isabela V; Nascimento, Thiago C; Ferreira-Machado, Alessandra B; Silva, Vânia L; Diniz, Cláudio G

2018-06-01

Fungi have a complex role in the intestinal tract, influencing health and disease, with dysbiosis contributing to obesity. Our objectives were to investigate fungal diversity in human gut microbiota among eutrophic, overweight, and obese. Epidemiological and nutritional information were collected from adult individuals, as well as stool samples processed for selective fungi isolation and identification by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (yeasts) or microculture (filamentous fungi). Further 18S rDNA sequencing was performed to confirm identification. The mean count of fungi was 241 CFU/g of feces. Differences in the population level of the filamentous fungi were observed within eutrophic and obese groups. Overall, 34 genera were identified. The predominant phylum was Ascomycota with 20 different genera, followed by Basidiomycota and Zygomycota. As for Ascomycota, the most prevalent species were Paecilomyces sp., Penicillium sp., Candida sp., Aspergillus sp., Fonsecaea sp., and Geotrichum sp. (76.39, 65.28, 59.72, 58.33, 12.50, and 9.72%, respectively). As for Basidiomycota, Trichosporon sp. and Rhodotorula sp. were the most prevalent (30.56 and 15.28%, respectively), and for Zygomycota, Rhizopus sp. and Mucor sp. were the most numerous (15.28 and 9.72%, respectively). As expected there is a mycobiota shift towards obesity, with slightly higher diversity associated to eutrophic individuals. This mycobiota shift seems also to be related to the nutritional behavior of the individuals, as observed that the macronutrients intake may be positively related to the different fungi occurrences. Other studies are needed to better understand relationships between mycobiota and obesity, which could be used in future obesity treatments.

Water Age Responses to Weather Conditions in a Hyper-Eutrophic Channel Reservoir in Southern China

Directory of Open Access Journals (Sweden)

Wei Du

2016-08-01

Full Text Available Channel reservoirs have the characteristics of both rivers and lakes, in which hydrodynamic conditions and the factors affecting the eutrophication process are complex and highly affected by weather conditions. Water age at any location in the reservoir is used as an indicator for describing the spatial and temporal variations of water exchange and nutrient transport. The hyper-eutrophic Changtan Reservoir (CTR in Southern China was investigated. Three weather conditions including wet, normal, and dry years were considered for assessing the response of water age by using the coupled watershed model Soil Water Assessment Tool (SWAT and the three-dimensional hydrodynamic model Environmental Fluid Hydrodynamic Code (EFDC. The results showed that the water age in CTR varied tremendously under different weather conditions. The averaged water ages at the downstream of CTR were 3 d, 60 d, and 110 d, respectively in the three typical wet, normal, and dry years. The highest water ages at the main tributary were >70 d, >100 d, and >200 d, respectively. The spatial distribution of water ages in the tributaries and the reservoir were mainly affected by precipitation. This paper provides useful information on water exchange and transport pathways in channel reservoir, which will be helpful in understanding nutrient dynamics for controlling algal blooms.

Possible future effects of large-scale algae cultivation for biofuels on coastal eutrophication in Europe.

Science.gov (United States)

Blaas, Harry; Kroeze, Carolien

2014-10-15

Biodiesel is increasingly considered as an alternative for fossil diesel. Biodiesel can be produced from rapeseed, palm, sunflower, soybean and algae. In this study, the consequences of large-scale production of biodiesel from micro-algae for eutrophication in four large European seas are analysed. To this end, scenarios for the year 2050 are analysed, assuming that in the 27 countries of the European Union fossil diesel will be replaced by biodiesel from algae. Estimates are made for the required fertiliser inputs to algae parks, and how this may increase concentrations of nitrogen and phosphorus in coastal waters, potentially leading to eutrophication. The Global NEWS (Nutrient Export from WaterSheds) model has been used to estimate the transport of nitrogen and phosphorus to the European coastal waters. The results indicate that the amount of nitrogen and phosphorus in the coastal waters may increase considerably in the future as a result of large-scale production of algae for the production of biodiesel, even in scenarios assuming effective waste water treatment and recycling of waste water in algae production. To ensure sustainable production of biodiesel from micro-algae, it is important to develop cultivation systems with low nutrient losses to the environment. Copyright © 2014 Elsevier B.V. All rights reserved.

Interdisciplinarity as an Emergent Property: The Research Project “CINTERA” and the Study of Marine Eutrophication

Directory of Open Access Journals (Sweden)

Jennifer Bailey

2015-07-01

Full Text Available Research projects combining different disciplines are increasingly common and sought after by funding agencies looking for ways to achieve environmental, social, and economic sustainability. Creating and running a truly integrated research project that combines very different disciplines is, however, no easy task. Large-scale efforts to create interdisciplinary or transdisciplinary research efforts have reported on their experiences in trying to achieve this goal. This article shares the methods, challenges and achievements experienced by a smaller group of researchers who have developed an interdisciplinary approach based on former results of Norwegian and Chilean experiments. The project “A Cross-disciplinary Integrated Eco-system Eutrophication Research and Management Approach” (CINTERA, funded by the Research Council of Norway (RCN, project 216607, brings together the fields of political science, economics, marine biology/oceanography and marine bio-geo-chemistry to improve the understanding of marine eutrophication and its possible socio-economic impacts. CINTERA is a multidisciplinary project that evolved into an interdisciplinary project and in so doing, transformed the attitudes of participants. The transformative process was generated particularly by the need to work closely together in making the CINTERA project useful for policy-makers.

Evidence for an asthma risk locus on chromosome Xp: a replication linkage study

DEFF Research Database (Denmark)

Brasch-Andersen, C; Møller, M U; Haagerup, A

2008-01-01

replication sample as used in the present study. The aim of the study was to replicate linkage to candidate regions for asthma in an independent Danish sample. METHODS: We performed a replication study investigating linkage to candidate regions for asthma on chromosomes 1p36.31-p36.21, 5q15-q23.2, 6p24.3-p22...... studies have been carried out the results are still conflicting and call for replication experiments. A Danish genome-wide scan has prior reported evidence for candidate regions for asthma susceptibility genes on chromosomes 1p, 5q, 6p, 12q and Xp. Linkage to chromosome 12q was later confirmed in the same.......3, and Xp22.31-p11.4 using additional markers in an independent set of 136 Danish asthmatic sib pair families. RESULTS: Nonparametric multipoint linkage analyses yielded suggestive evidence for linkage to asthma to chromosome Xp21.2 (MLS 2.92) but failed to replicate linkage to chromosomes 1p36.31-p36.21, 5...

The acceptability of conducting data linkage research without obtaining consent: lay people's views and justifications.

Science.gov (United States)

Xafis, Vicki

2015-11-17

A key ethical issue arising in data linkage research relates to consent requirements. Patients' consent preferences in the context of health research have been explored but their consent preferences regarding data linkage specifically have been under-explored. In addition, the views on data linkage are often those of patient groups. As a result, little is known about lay people's views and their preferences about consent requirements in the context of data linkage. This study explores lay people's views and justifications regarding the acceptability of conducting data linkage research without obtaining consent. A qualitative study explored lay people's views regarding consent requirements in data linkage via four hypothetical data linkage scenarios of increasing complexity. Prior to considering the scenarios, participants were provided with information regarding best practice data linkage processes via discussion and a diagrammatic representation of the process. Lay people were able to understand the intricate processes involved in data linkage and the key protections afforded within a short amount of time. They were supportive of data linkage research and, on the whole, believed it should be conducted without consent provided a data linkage organization de-identifies the data used so that researchers do not handle identifiable data. Many thought that de-identified data holds a different status to identifiable data and should be used without specific consent in research that aims to benefit society. In weighing up conflicting values and interests, participants shifted consent preferences before arriving at their final consent preference for each scenario and provided justifications for their choices. They considered the protection of people's information, societal benefits, and the nature and constraints of research and recognized that these need to be balanced. With some exposure to the features of data linkage, lay people have the capacity to understand the

The contribution of phytoplankton degradation to chromophoric dissolved organic matter (CDOM) in eutrophic shallow lakes: Field and experimental evidence

NARCIS (Netherlands)

Zhang, Y.; Van Dijk, M.A.; Liu, M.; Zhu, G.; Qin, B.

2009-01-01

Eight field campaigns in the eutrophic, shallow, Lake Taihu in the summers from 2005 to 2007, and a phytoplankton degradation experiment of 33 days, were carried out to determine the contribution of phytoplankton degradation to CDOM. Significant and positive correlations were found between the CDOM

Biodiesel production from sediments of a eutrophic reservoir

International Nuclear Information System (INIS)

Kuchkina, A.Yu.; Gladyshev, M.I.; Sushchik, N.N.; Kravchuk, E.S.; Kalachova, G.S.

2011-01-01

Sediments from eutrophic reservoir Bugach (Siberia, Russia) were tested for possibility to produce biodiesel. We supposed that the sediments could be a promising biodiesel producer. The major reason of high price of biodiesel fuel is cost of a raw material. The use of dredging sediments for biodiesel production reduces production costs, because the dredging sediments are by-products which originated during lake restoration actions, and are free of cost raw materials. Lipid content in sediments was 0.24% of dry weight. To assess the potential of from sediments as a substitute of diesel fuel, the properties of the biodiesel such as cetane number, iodine number and heat of combustion were calculated. All of this parameters complied with limits established by EN 14214 and EN 14213 related to biodiesel quality. -- Highlights: → Dredging sediments were considered as a new feedstock for biodiesel production. → Lipid and fatty acid content in the sediments were determined. → Main properties of the biodiesel were calculated basing on fatty acid composition. → The properties well complied with limits established in biodiesel standards.

Water reservoirs - aquatic ecosystems subject to eutrophication processes

International Nuclear Information System (INIS)

Ionita, Veronica

1997-01-01

The paper presents some aspects relating to eutrophication of Batca Doamnei and Reconstructia hydropower lakes situated near Piatra Neamt town. The presence of phosphorus salts in the two water reservoirs (ten times the admissible content) is responsible for excessive growth of plants. In Reconstructia lake the diversity of species is also explained by the existence of large amounts of nitrogen salts. The general characteristic of aquatic macrophyte is the resistance to large variations of environmental factors (water level, currents, temperature, turbidity, organic material content), adaptation to water pollution conditions and development of adverse condition resistant forms. Besides Cladophora, a harmful species in fishing waters when growing excessively, others species are favorable to aquatic life and help to the consolidation of complex lake biocenoses, providing support, food and habitation for many small animal species which also favor other species economically valuable. The aquatic macrophytes are true biological filters which maintain the natural auto-purging potential of the waters. Taking into consideration these facts, the direct and indirect effects of plant destruction on the whole ecosystem should be carefully analyzed

Model reduction of detailed-balanced reaction networks by clustering linkage classes

NARCIS (Netherlands)

Rao, Shodhan; Jayawardhana, Bayu; van der Schaft, Abraham; Findeisen, Rolf; Bullinger, Eric; Balsa-Canto, Eva; Bernaerts, Kristel

2016-01-01

We propose a model reduction method that involves sequential application of clustering of linkage classes and Kron reduction. This approach is specifically useful for chemical reaction networks with each linkage class having less number of reactions. In case of detailed balanced chemical reaction

Balancing of linkages and robot manipulators advanced methods with illustrative examples

CERN Document Server

Arakelian, Vigen

2015-01-01

In this book advanced balancing methods for planar and spatial linkages, hand operated and automatic robot manipulators are presented. It is organized into three main parts and eight chapters. The main parts are the introduction to balancing, the balancing of linkages and the balancing of robot manipulators. The review of state-of-the-art literature including more than 500 references discloses particularities of shaking force/moment balancing and gravity compensation methods. Then new methods for balancing of linkages are considered. Methods provided in the second part of the book deal with the partial and complete shaking force/moment balancing of various linkages. A new field for balancing methods applications is the design of mechanical systems for fast manipulation. Special attention is given to the shaking force/moment balancing of robot manipulators. Gravity balancing methods are also discussed. The suggested balancing methods are illustrated by numerous examples.

The linkage between knowledge management practices and company Performance: Empirical evidence

Directory of Open Access Journals (Sweden)

Nausheen Syed

2013-03-01

Full Text Available Purpose: This study explores the linkage between Knowledge management practices and company performance. Keeping in view the theoretical and empirical importance, the present study examines the predicting linkage of Knowledge management practices (sharing of best practices and building of consistent process, continues employee learning, effective management of knowledge, innovative culture development, and management of core competencies with company performance.Methodology: The study was carried out on purposively selected sample of 412 employees at different managerial positions. They were administered questionnaires including Knowledge Management Practices and company performance. Data was operated by using SPSS version 20.Correlation and regression analysis was done to establish the relationship between various Knowledge management practices and company performance.Findings: Results of this study illustrated that all selected Knowledge management were positively related to company performance. Based on the findings, and management of core competencies was the strongest predictor of company performance, followed by innovative culture development, effective management of knowledge and sharing of best practices and building of consistent process, continues employee learning.Research limitations/implications: The paper focuses on examining the perceptual impacts of Knowledge management (KM practices on company performance. The interpretation of results should be taken with caution.Value: The aim of this research is to investigate the relationship between Knowledge management and company performance, study the importance of Knowledge management as a source of sustainable competitive advantages for companies and to investigate how the introduction of Knowledge management practices facilitates company performance to improve. The practices that have a more positive influence on company performance are also discussed.

Genome-wide linkage scan to identify loci associated with type 2 diabetes and blood lipid phenotypes in the Sikh Diabetes Study.

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Dharambir K Sanghera

Full Text Available In this investigation, we have carried out an autosomal genome-wide linkage analysis to map genes associated with type 2 diabetes (T2D and five quantitative traits of blood lipids including total cholesterol, high-density lipoprotein (HDL cholesterol, low-density lipoprotein (LDL cholesterol, very low-density lipoprotein (VLDL cholesterol, and triglycerides in a unique family-based cohort from the Sikh Diabetes Study (SDS. A total of 870 individuals (526 male/344 female from 321 families were successfully genotyped using 398 polymorphic microsatellite markers with an average spacing of 9.26 cM on the autosomes. Results of non-parametric multipoint linkage analysis using S(all statistics (implemented in Merlin did not reveal any chromosomal region to be significantly associated with T2D in this Sikh cohort. However, linkage analysis for lipid traits using QTL-ALL analysis revealed promising linkage signals with p≤0.005 for total cholesterol, LDL cholesterol, and HDL cholesterol at chromosomes 5p15, 9q21, 10p11, 10q21, and 22q13. The most significant signal (p = 0.0011 occurred at 10q21.2 for HDL cholesterol. We also observed linkage signals for total cholesterol at 22q13.32 (p = 0.0016 and 5p15.33 (p = 0.0031 and for LDL cholesterol at 10p11.23 (p = 0.0045. Interestingly, some of linkage regions identified in this Sikh population coincide with plausible candidate genes reported in recent genome-wide association and meta-analysis studies for lipid traits. Our study provides the first evidence of linkage for loci associated with quantitative lipid traits at four chromosomal regions in this Asian Indian population from Punjab. More detailed examination of these regions with more informative genotyping, sequencing, and functional studies should lead to rapid detection of novel targets of therapeutic importance.

Investigating the Evolution of Linkage Dynamics among Equity Markets Using Network Models and Measures: The Case of Asian Equity Market Integration

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Biplab Bhattacharjee

2017-12-01

Full Text Available The state of cross-market linkage structures and its stability over varying time-periods play a key role in the performance of international diversified portfolios. There has been an increasing interest of global investors in emerging capital markets in the Asian region. In this setting, an investigation into the temporal dynamics of cross-market linkage structures becomes significant for the selection and optimal allocation of securities in an internationally-diversified portfolio. In the quest for this, in the current study, weighted network models along with network metrics are employed to decipher the underlying cross-market linkage structures among Asian markets. The study analyses the daily return data of fourteen major Asian indices for a period of 14 years (2002–2016. The topological properties of the network are computed using centrality measures and measures of influence strength and are investigated over temporal scales. In particular, the overall influence strengths and India-specific influence strengths are computed and examined over a temporal scale. Threshold filtering is also performed to characterize the dynamics related to the linkage structure of these networks. The impacts of the 2008 financial crisis on the linkage structural patterns of these equity networks are also investigated. The key findings of this study include: a set of central and peripheral indices, the evolution of the linkage structures over the 2002–2016 period and the linkage dynamics during times of market stress. Mainly, the set of indices possessing influence over the Asian region in general and the Indian market in particular is also identified. The findings of this study can be utilized in effective systemic risk management and for the selection of an optimally-diversified portfolio, resilient to system-level shocks.

A literature review of record linkage procedures focusing on infant health outcomes

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Carla Jorge Machado

Full Text Available Record linkage is a powerful tool in assembling information from different data sources and has been used by a number of public health researchers. In this review, we provide an overview of the record linkage methodologies, focusing particularly on probabilistic record linkage. We then stress the purposes and research applications of linking records by focusing on studies of infant health outcomes based on large data sets, and provide a critical review of the studies in Brazil.

Accuracy of computer-aided ultrasound as compared with magnetic resonance imaging in the evaluation of nonalcoholic fatty liver disease in obese and eutrophic adolescents

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José Hermes Ribas do Nascimento

2015-08-01

Full Text Available AbstractObjective:To compare the accuracy of computer-aided ultrasound (US and magnetic resonance imaging (MRI by means of hepatorenal gradient analysis in the evaluation of nonalcoholic fatty liver disease (NAFLD in adolescents.Materials and Methods:This prospective, cross-sectional study evaluated 50 adolescents (aged 11–17 years, including 24 obese and 26 eutrophic individuals. All adolescents underwent computer-aided US, MRI, laboratory tests, and anthropometric evaluation. Sensitivity, specificity, positive and negative predictive values and accuracy were evaluated for both imaging methods, with subsequent generation of the receiver operating characteristic (ROC curve and calculation of the area under the ROC curve to determine the most appropriate cutoff point for the hepatorenal gradient in order to predict the degree of steatosis, utilizing MRI results as the gold-standard.Results:The obese group included 29.2% girls and 70.8% boys, and the eutrophic group, 69.2% girls and 30.8% boys. The prevalence of NAFLD corresponded to 19.2% for the eutrophic group and 83% for the obese group. The ROC curve generated for the hepatorenal gradient with a cutoff point of 13 presented 100% sensitivity and 100% specificity. As the same cutoff point was considered for the eutrophic group, false-positive results were observed in 9.5% of cases (90.5% specificity and false-negative results in 0% (100% sensitivity.Conclusion:Computer-aided US with hepatorenal gradient calculation is a simple and noninvasive technique for semiquantitative evaluation of hepatic echogenicity and could be useful in the follow-up of adolescents with NAFLD, population screening for this disease as well as for clinical studies.

Sustaining innovations : schools, institutions and linkages in the Cuzco region, Peru

NARCIS (Netherlands)

ChavezTafur, J.

1998-01-01

This thesis is about linkages between the different institutions operating in the rural areas and the contributions these linkages provide. Numerous activities are found taking place in the rural areas of Peru. Many are the result of a specific intervention, designed and implemented towards

Bayesian estimates of linkage disequilibrium

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Abad-Grau María M

2007-06-01

Full Text Available Abstract Background The maximum likelihood estimator of D' – a standard measure of linkage disequilibrium – is biased toward disequilibrium, and the bias is particularly evident in small samples and rare haplotypes. Results This paper proposes a Bayesian estimation of D' to address this problem. The reduction of the bias is achieved by using a prior distribution on the pair-wise associations between single nucleotide polymorphisms (SNPs that increases the likelihood of equilibrium with increasing physical distances between pairs of SNPs. We show how to compute the Bayesian estimate using a stochastic estimation based on MCMC methods, and also propose a numerical approximation to the Bayesian estimates that can be used to estimate patterns of LD in large datasets of SNPs. Conclusion Our Bayesian estimator of D' corrects the bias toward disequilibrium that affects the maximum likelihood estimator. A consequence of this feature is a more objective view about the extent of linkage disequilibrium in the human genome, and a more realistic number of tagging SNPs to fully exploit the power of genome wide association studies.

Peat accretion and phosphorus accumulation along a eutrophication gradient in the northern Everglades

International Nuclear Information System (INIS)

Craft, C.B.; Richardson, C.J.

1993-01-01

Recent rates of peat accretion (as determined by Cs-137) and N, P, organic C, Ca and Na accumulation were measured along a 10 km eutrophication gradient in the northern Everglades area of Water Conservation Area 2A (WCA 2A) that has received agricultural drainage from the Hillsboro canal for the past 25-30 yrs. Rates of peat accretion were highest at sampling locations closest to the Hillsboro canal. Phosphorus and Na accumulation were a function of both peat accretion and soil P and Na concentrations. Although sodium enrichment of the peat was limited to 1.6 km downstream of the Hillsboro canal, increased rates of Na accumulation penetrated 5.2 km downstream of the Hillsboro canal, the extent of the area of enhanced peat accretion. In contrast to P and Na, there was no difference in the concentration of soil organic C, N and Ca along the eutrophication gradient. However, there was a gradient of organic C, N and Ca accumulation corresponding to the area of enhanced peat accretion. The areal extent of enhanced peat accretion and organic C, N, Ca and Na accumulation encompasses approximately 7700 ha of the northern part of WCA 2A. The area of enhanced P accumulation is larger, covering 11,500 ha or 26% of the total area of WCA 2A. The findings suggest that P accumulation is dependent on the P concentration in the water column and that decreasing P loadings per unit area result in less P storage per unit area

Linking climate change mitigation and coastal eutrophication management through biogas technology

DEFF Research Database (Denmark)

Kaspersen, Bjarke Stoltze; Christensen, Thomas Budde; Fredenslund, Anders Michael

2016-01-01

concept for anaerobic co-digestion of food industry residues, manure and beach-cast seaweed has been developed and tested in order to quantify the potential for synergies between climate change mitigation and coastal eutrophication management in the Køge Bay catchment. The biogas plant, currently under...... and phosphorous loads to Køge Bay are estimated to be reduced by approx. 63tyr.-1 and 9tyr.-1, respectively, contributing to the achievement of more than 70% of the nutrient reduction target set for Køge Bay in the first WFD river basin management plan. This study shows that anaerobic co-digestion of the specific...... environment are integrated into the design and decision processes can support the development of this kind of holistic bioenergy solutions....

Missing Linkages in California's Landscape [ds420

Data.gov (United States)

California Natural Resource Agency — The critical need for conserving landscape linkages first came to the forefront of conservation thinking in California in November 2000, when a statewide interagency...

Missing Linkages in California's Landscape [ds420

Data.gov (United States)

California Department of Resources — The critical need for conserving landscape linkages first came to the forefront of conservation thinking in California in November 2000, when a statewide interagency...

Characterization of Phosphate Solubilizing Bacteria in Sediments from a Shallow Eutrophic Lake and a Wetland: Isolation, Molecular Identification and Phosphorus Release Ability Determination

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Jie Tang

2010-11-01

Full Text Available The transformation of phosphorus (P is a major factor of lake eutrophication, and phosphate releasing bacteria play an important role in the release process. Experiments were conducted to investigate P content and characterize phosphate solubilizing bacterial composition at the molecular level in a shallow eutrophic lake and a wetland. Results showed that P concentrations were relatively high and derived from agricultural runoff and domestic or industrial pollution. Enumeration and molecular identification of these strains indicated that these bacterial groups were abundant in the ecosystem and various kinds of bacteria participated in the phosphorus release process. Twelve phosphate solubilizing bacteria, including eight organic P-solubilizing bacteria (OPBs and four inorganic P-solubilizing bacteria (IPBs, which belonged to three different families, were isolated and identified. Cupriavidus basilensis was found for the first time to have the ability to mineralize organic P (OP. Laboratory tests on P release ability revealed that IPBs were more effective at releasing P than OPBs. The most efficient IPB strain could accumulate over 170 mg·L-1 orthophosphate, while the equivalent OPB strain only liberated less than 4 mg·L-1 orthophosphate in liquid culture. The results obtained from this investigation should help clarify the roles of microorganisms in aquatic systems and the mechanisms of eutrophication.

Markov chain Monte Carlo linkage analysis: effect of bin width on the probability of linkage.

Science.gov (United States)

Slager, S L; Juo, S H; Durner, M; Hodge, S E

2001-01-01

We analyzed part of the Genetic Analysis Workshop (GAW) 12 simulated data using Monte Carlo Markov chain (MCMC) methods that are implemented in the computer program Loki. The MCMC method reports the "probability of linkage" (PL) across the chromosomal regions of interest. The point of maximum PL can then be taken as a "location estimate" for the location of the quantitative trait locus (QTL). However, Loki does not provide a formal statistical test of linkage. In this paper, we explore how the bin width used in the calculations affects the max PL and the location estimate. We analyzed age at onset (AO) and quantitative trait number 5, Q5, from 26 replicates of the general simulated data in one region where we knew a major gene, MG5, is located. For each trait, we found the max PL and the corresponding location estimate, using four different bin widths. We found that bin width, as expected, does affect the max PL and the location estimate, and we recommend that users of Loki explore how their results vary with different bin widths.

Health problems in childhood cancer survivors: Linkage studies and guideline development

NARCIS (Netherlands)

Font-Gonzalez, A.

2016-01-01

This thesis comprises two parts. The first part of this thesis aims to increase the evidence on the burden of disease in childhood cancer survivors and to define high-risk groups of survivors by using medical record linkage studies. A two-step record linkage methodology between Dutch national

Resilience of alternative stable states during the recovery of shallow lakes from eutrophication: Lake Veluwe as a case study

NARCIS (Netherlands)

Ibelings, B.W.; Portielje, R.; Lammens, E.H.R.R.; Meijer, M.L.; Noordhuis, R.; van den Berg, Marcel S.; Joosse, W.; Scheffer, M.

2007-01-01

In this paper we analyze a long-term dataset on the recovery from eutrophication of Lake Veluwe (The Netherlands). Clear hysteresis was observed in a number of ecosystem variables: the route to recovery differed significantly from the route that led to loss of clear water. The macrophyte dominated

Base cation depletion, eutrophication and acidification of species-rich grasslands in response to long-term simulated nitrogen deposition

Energy Technology Data Exchange (ETDEWEB)

Horswill, Paul [Department of Animal and Plant Sciences, University of Sheffield, Alfred Denny Building, Western Bank, Sheffield S10 2TN (United Kingdom)], E-mail: paul.horswill@naturalengland.org.uk; O' Sullivan, Odhran; Phoenix, Gareth K.; Lee, John A.; Leake, Jonathan R. [Department of Animal and Plant Sciences, University of Sheffield, Alfred Denny Building, Western Bank, Sheffield S10 2TN (United Kingdom)

2008-09-15

Pollutant nitrogen deposition effects on soil and foliar element concentrations were investigated in acidic and limestone grasslands, located in one of the most nitrogen and acid rain polluted regions of the UK, using plots treated for 8-10 years with 35-140 kg N ha{sup -2} y{sup -1} as NH{sub 4}NO{sub 3}. Historic data suggests both grasslands have acidified over the past 50 years. Nitrogen deposition treatments caused the grassland soils to lose 23-35% of their total available bases (Ca, Mg, K, and Na) and they became acidified by 0.2-0.4 pH units. Aluminium, iron and manganese were mobilised and taken up by limestone grassland forbs and were translocated down the acid grassland soil. Mineral nitrogen availability increased in both grasslands and many species showed foliar N enrichment. This study provides the first definitive evidence that nitrogen deposition depletes base cations from grassland soils. The resulting acidification, metal mobilisation and eutrophication are implicated in driving floristic changes. - Nitrogen deposition causes base cation depletion, acidification and eutrophication of semi-natural grassland soils.

The Importance of Geographical Proximity for New Product Development Activities within Inter-firm Linkages

DEFF Research Database (Denmark)

Dahlgren, Johan Henrich

important as a resource and where collaboration partners are important. Hypotheses are tested by means of a quantitative analysis of a data set containing information about 4842 domestic and international inter-firm linkages of Danish firms in manufacturing industries. The findings in this analysis exhibit...... for international linkages. It is further suggested closer geographical distance for inter-firm linkages with medium and high level of interaction, suppliers or customers accounting for more than one third of total purchases or sales, and for linkages lasting for at least 10 years.Key words: capabilities, economics...

Bacterial zoonoses of fishes: a review and appraisal of evidence for linkages between fish and human infections.

Science.gov (United States)

Gauthier, David T

2015-01-01

Human contact with and consumption of fishes presents hazards from a range of bacterial zoonotic infections. Whereas many bacterial pathogens have been presented as fish-borne zoonoses on the basis of epidemiological and phenotypic evidence, genetic identity between fish and human isolates is not frequently examined or does not provide support for transmission between these hosts. In order to accurately assess the zoonotic risk from exposure to fishes in the context of aquaculture, wild fisheries and ornamental aquaria, it is important to critically examine evidence of linkages between bacteria infecting fishes and humans. This article reviews bacteria typically presented as fish-borne zoonoses, and examines the current strength of evidence for this classification. Of bacteria generally described as fish-borne zoonoses, only Mycobacterium spp., Streptococcus iniae, Clostridium botulinum, and Vibrio vulnificus appear to be well-supported as zoonoses in the strict sense. Erysipelothrix rhusiopathiae, while transmissible from fishes to humans, does not cause disease in fishes and is therefore excluded from the list. Some epidemiological and/or molecular linkages have been made between other bacteria infecting both fishes and humans, but more work is needed to elucidate routes of transmission and the identity of these pathogens in their respective hosts at the genomic level. Copyright © 2014 Elsevier Ltd. All rights reserved.

Colorimetric Chemical Differentiation and Detection of Phosphorus in Eutrophic and High Particulate Waters: Advantages of a New Monitoring Approach

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Lisa Felgentreu

2018-06-01

Full Text Available Phosphorus (P is a key factor forcing eutrophication in limnic and marine systems, and all monitoring programs for water quality accordingly include P determinations. However, traditional monitoring does not allow an analysis of the different components involved in the P cycle taking place in the water column. Nonetheless, the implementation of measures addressing eutrophication requires a full understanding of the processes involved in the transformation and transport of P, in all its chemical forms. In this study, the P categories present in a river and its estuary in northern Germany, which discharge into the Baltic Sea, were characterized. Using the molybdenum blue method we found that the classification of P into the traditional fractions (DIP, DOP, POP applied in the ocean cannot be applied to turbid waters such as rivers because interferences between the fractions seems to occur. Therefore a new nomenclature has been introduced. In addition to total phosphorus (TP and dissolved molybdate-reactive phosphorus (DRP; previously referred to as inorganic phosphorus, dissolved non-molybdate-reactive phosphorus (DNP, particulate molybdatereactive phosphorus (PRP, and particulate non-molybdate-reactive phosphorus (PNP were distinguished. The high spatial and temporal variations in the proportions of these forms with respect to the TP concentration well-demonstrate the complexity of the P cycle and the involved P fractions and emphasize the need for expanded monitoring approach. The potential of eutrophication could be underestimated if not all P categories were considered. With the new operational nomenclature the common and standardized molybdenum blue reaction could be used to implement the analysis of various P components into regular monitoring programs.

INTERACTION OF TRADE AND FINANCIAL LINKAGES IN THE FREE TRADE ZONES

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V. Shevchenko

2014-09-01

Full Text Available Different models of free trade agreements (FTA and free trade zones (FTZ are considered in the article, argued the complex approach to their structures and results under unstable global economic environment. The typology of the free trade zones models and financial linkages types between countries have been developed. Approaches to the results of the free trade zones have been argued. It has been discovered that for the free trade zones of transitional countries the prevailing are tarde flows concentration whereas financial and investment linkages are acting with developed countries. The main directions of increasing of the financial linkages results in the free trade zones have been discovered.

A new method for assessing how sensitivity and specificity of linkage studies affects estimation.

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Cecilia L Moore

Full Text Available While the importance of record linkage is widely recognised, few studies have attempted to quantify how linkage errors may have impacted on their own findings and outcomes. Even where authors of linkage studies have attempted to estimate sensitivity and specificity based on subjects with known status, the effects of false negatives and positives on event rates and estimates of effect are not often described.We present quantification of the effect of sensitivity and specificity of the linkage process on event rates and incidence, as well as the resultant effect on relative risks. Formulae to estimate the true number of events and estimated relative risk adjusted for given linkage sensitivity and specificity are then derived and applied to data from a prisoner mortality study. The implications of false positive and false negative matches are also discussed.Comparisons of the effect of sensitivity and specificity on incidence and relative risks indicate that it is more important for linkages to be highly specific than sensitive, particularly if true incidence rates are low. We would recommend that, where possible, some quantitative estimates of the sensitivity and specificity of the linkage process be performed, allowing the effect of these quantities on observed results to be assessed.

A 200 year sedimentary record of progressive eutrophication in lake Greifen (Switzerland): Implications for the origin of organic-carbon-rich sediments

Science.gov (United States)

Hollander, David J.; McKenzie, Judith A.; Lo Ten Haven, H.

1992-09-01

Over the past 200 years Lake Greifen, a small lake in northeastern Switzerland, has undergone dramatic changes in primary productivity and eutrophication due to increased nutrient supply from agricultural activity and industrialization. A 40 year historical record of the water-column chemistry indicates that productivity and eutrophication reached a maximum in 1974, after which stricter regulations on the input of nutrients resulted in a progressive decrease. Collected cores show the sedimentary expression of this anthropogenically induced eutrophication by a well-developed annual sedimentation and by enhanced values of total organic carbon, organic-carbon accumulation rates, and hydrogen indices (HI) of the kerogens. Analyses of the carbon isotopic composition of sedimentary carbonates and organic matter reveal that the fractionation between these two phases varies with the HI of kerogens. This observation is explicable in terms of changing productivity and preservation of the organic matter, and the CO2(aq) budget of the water body. We propose that if high primary productivity were primarily responsible for the preservation and accumulation of organic matter, then a negative correlation will occur between Δδ13Ccalcite-organic matter (Δδ13Ccal-om) and HI values. In an environment with relatively low to moderate productivity but with bottom-water anoxia, a positive correlation will exist between Δδ13Ccal-om and HI values. This study of Lake Greifen has implications for understanding paleoenvironmental controls on ancient organic-carbon-rich sediments.

Point-of-Care HIV Testing and Linkage in an Urban Cohort in the Southern US

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Anne Zinski

2013-01-01

Full Text Available The Southern states experience the highest rates of HIV and AIDS in the US, and point-of-care (POC testing outside of primary care may contribute to status awareness in medically underserved populations in this region. To evaluate POC screening and linkage to care at an urban south site, analyses were performed on a dataset of 3,651 individuals from an integrated rapid-result HIV testing and linkage program to describe this test-seeking cohort and determine trends associated with screening, results, and linkage to care. Four percent of the population had positive results. We observed significant differences by test result for age, race and gender, reported risk behaviors, test location, and motivation for screening. The overall linkage rate was 86%, and we found significant differences for clients who were linked to HIV care versus persons whose linkage could not be confirmed with respect to race and gender, location, and motivation. The linkage rate for POC testing that included a comprehensive intake visit and colocated primary care services for in-state residents was 97%. Additional research on integrated POC screening and linkage methodologies that provide intake services at time of testing is essential for increasing status awareness and improving linkage to HIV care in the US.

Cytogenetic characterization and AFLP-based genetic linkage mapping for the butterfly Bicyclus anynana, covering all 28 karyotyped chromosomes.

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Arjen E Van't Hof

Full Text Available BACKGROUND: The chromosome characteristics of the butterfly Bicyclus anynana, have received little attention, despite the scientific importance of this species. This study presents the characterization of chromosomes in this species by means of cytogenetic analysis and linkage mapping. METHODOLOGY/PRINCIPAL FINDINGS: Physical genomic features in the butterfly B. anynana were examined by karyotype analysis and construction of a linkage map. Lepidoptera possess a female heterogametic W-Z sex chromosome system. The WZ-bivalent in pachytene oocytes of B. anynana consists of an abnormally small, heterochromatic W-chromosome with the Z-chromosome wrapped around it. Accordingly, the W-body in interphase nuclei is much smaller than usual in Lepidoptera. This suggests an intermediate stage in the process of secondary loss of the W-chromosome to a ZZ/Z sex determination system. Two nucleoli are present in the pachytene stage associated with an autosome and the WZ-bivalent respectively. Chromosome counts confirmed a haploid number of n = 28. Linkage mapping had to take account of absence of crossing-over in females, and of our use of a full-sib crossing design. We developed a new method to determine and exclude the non-recombinant uninformative female inherited component in offspring. The linkage map was constructed using a novel approach that uses exclusively JOINMAP-software for Lepidoptera linkage mapping. This approach simplifies the mapping procedure, avoids over-estimation of mapping distance and increases the reliability of relative marker positions. A total of 347 AFLP markers, 9 microsatellites and one single-copy nuclear gene covered all 28 chromosomes, with a mapping distance of 1354 cM. Conserved synteny of Tpi on the Z-chromosome in Lepidoptera was confirmed for B. anynana. The results are discussed in relation to other mapping studies in Lepidoptera. CONCLUSIONS/SIGNIFICANCE: This study adds to the knowledge of chromosome structure and

A food web modeling analysis of a Midwestern, USA eutrophic lake dominated by non-native Common Carp and Zebra Mussels

Science.gov (United States)

Colvin, Michael E.; Pierce, Clay; Stewart, Timothy W.

2015-01-01

Food web modeling is recognized as fundamental to understanding the complexities of aquatic systems. Ecopath is the most common mass-balance model used to represent food webs and quantify trophic interactions among groups. We constructed annual Ecopath models for four consecutive years during the first half-decade of a zebra mussel invasion in shallow, eutrophic Clear Lake, Iowa, USA, to evaluate changes in relative biomass and total system consumption among food web groups, evaluate food web impacts of non-native common carp and zebra mussels on food web groups, and to interpret food web impacts in light of on-going lake restoration. Total living biomass increased each year of the study; the majority of the increase due to a doubling in planktonic blue green algae, but several other taxa also increased including a more than two-order of magnitude increase in zebra mussels. Common carp accounted for the largest percentage of total fish biomass throughout the study even with on-going harvest. Chironomids, common carp, and zebra mussels were the top-three ranking consumer groups. Non-native common carp and zebra mussels accounted for an average of 42% of the total system consumption. Despite the relatively high biomass densities of common carp and zebra mussel, food web impacts was minimal due to excessive benthic and primary production in this eutrophic system. Consumption occurring via benthic pathways dominated system consumption in Clear Lake throughout our study, supporting the argument that benthic food webs are significant in shallow, eutrophic lake ecosystems and must be considered if ecosystem-level understanding is to be obtained.

Siblings versus parents and friends: longitudinal linkages to adolescent externalizing problems

Science.gov (United States)

Defoe, Ivy N; Keijsers, Loes; Hawk, Skyler T; Branje, Susan; Dubas, Judith Semon; Buist, Kirsten; Frijns, Tom; van Aken, Marcel AG; Koot, Hans M; van Lier, Pol AC; Meeus, Wim

2013-01-01

Background: It is well documented that friends’ externalizing problems and negative parent–child interactions predict externalizing problems in adolescence, but relatively little is known about the role of siblings. This four-wave, multi-informant study investigated linkages of siblings’ externalizing problems and sibling–adolescent negative interactions on adolescents’ externalizing problems, while examining and controlling for similar linkages with friends and parents. Methods: Questionnaire data on externalizing problems and negative interactions were annually collected from 497 Dutch adolescents (M = 13.03 years, SD = 0.52, at baseline), as well as their siblings, mothers, fathers, and friends. Results: Cross-lagged panel analyses revealed modest unique longitudinal paths from sibling externalizing problems to adolescent externalizing problems, for male and female adolescents, and for same-sex and mixed-sex sibling dyads, but only from older to younger siblings. Moreover, these paths were above and beyond significant paths from mother–adolescent negative interaction and friend externalizing problems to adolescent externalizing problems, 1 year later. No cross-lagged paths existed between sibling–adolescent negative interaction and adolescent externalizing problems. Conclusions: Taken together, it appears that especially older sibling externalizing problems may be a unique social risk factor for adolescent externalizing problems, equal in strength to significant parents’ and friends’ risk factors. PMID:23398022

Contribution of waterborne nitrogen emissions to hypoxia-driven marine eutrophication: modelling of damage to ecosystems in life cycle impact assessment (LCIA)

DEFF Research Database (Denmark)

Cosme, Nuno Miguel Dias

Marine eutrophication refers to the ecosystem response to the loading of a growth limiting nutrient, typically nitrogen (N), to coastal waters, where it may cause several impacts. One of the possible impact pathways to these impacts involves the excessive depletion of dissolved oxygen hypoxia) in...... and atmospheric deposition as a consequence of fossil fuels combustion.......Marine eutrophication refers to the ecosystem response to the loading of a growth limiting nutrient, typically nitrogen (N), to coastal waters, where it may cause several impacts. One of the possible impact pathways to these impacts involves the excessive depletion of dissolved oxygen hypoxia......) in bottom waters. Hypoxia is identified as an important and widespread cause of disturbance to marine ecosystems and has been linked to the increasing anthropogenic pressure. This is driven by environmental emissions of reactive nitrogen, mainly from N-containing fertilizers used in agriculture...

Large-scale linkage analysis of 1302 affected relative pairs with rheumatoid arthritis

Science.gov (United States)

Hamshere, Marian L; Segurado, Ricardo; Moskvina, Valentina; Nikolov, Ivan; Glaser, Beate; Holmans, Peter A

2007-01-01

Rheumatoid arthritis is the most common systematic autoimmune disease and its etiology is believed to have both strong genetic and environmental components. We demonstrate the utility of including genetic and clinical phenotypes as covariates within a linkage analysis framework to search for rheumatoid arthritis susceptibility loci. The raw genotypes of 1302 affected relative pairs were combined from four large family-based samples (North American Rheumatoid Arthritis Consortium, United Kingdom, European Consortium on Rheumatoid Arthritis Families, and Canada). The familiality of the clinical phenotypes was assessed. The affected relative pairs were subjected to autosomal multipoint affected relative-pair linkage analysis. Covariates were included in the linkage analysis to take account of heterogeneity within the sample. Evidence of familiality was observed with age at onset (p << 0.001) and rheumatoid factor (RF) IgM (p << 0.001), but not definite erosions (p = 0.21). Genome-wide significant evidence for linkage was observed on chromosome 6. Genome-wide suggestive evidence for linkage was observed on chromosomes 13 and 20 when conditioning on age at onset, chromosome 15 conditional on gender, and chromosome 19 conditional on RF IgM after allowing for multiple testing of covariates. PMID:18466440

Conservation of gene linkage in dispersed vertebrate NK homeobox clusters.

Science.gov (United States)

Wotton, Karl R; Weierud, Frida K; Juárez-Morales, José L; Alvares, Lúcia E; Dietrich, Susanne; Lewis, Katharine E

2009-10-01

Nk homeobox genes are important regulators of many different developmental processes including muscle, heart, central nervous system and sensory organ development. They are thought to have arisen as part of the ANTP megacluster, which also gave rise to Hox and ParaHox genes, and at least some NK genes remain tightly linked in all animals examined so far. The protostome-deuterostome ancestor probably contained a cluster of nine Nk genes: (Msx)-(Nk4/tinman)-(Nk3/bagpipe)-(Lbx/ladybird)-(Tlx/c15)-(Nk7)-(Nk6/hgtx)-(Nk1/slouch)-(Nk5/Hmx). Of these genes, only NKX2.6-NKX3.1, LBX1-TLX1 and LBX2-TLX2 remain tightly linked in humans. However, it is currently unclear whether this is unique to the human genome as we do not know which of these Nk genes are clustered in other vertebrates. This makes it difficult to assess whether the remaining linkages are due to selective pressures or because chance rearrangements have "missed" certain genes. In this paper, we identify all of the paralogs of these ancestrally clustered NK genes in several distinct vertebrates. We demonstrate that tight linkages of Lbx1-Tlx1, Lbx2-Tlx2 and Nkx3.1-Nkx2.6 have been widely maintained in both the ray-finned and lobe-finned fish lineages. Moreover, the recently duplicated Hmx2-Hmx3 genes are also tightly linked. Finally, we show that Lbx1-Tlx1 and Hmx2-Hmx3 are flanked by highly conserved noncoding elements, suggesting that shared regulatory regions may have resulted in evolutionary pressure to maintain these linkages. Consistent with this, these pairs of genes have overlapping expression domains. In contrast, Lbx2-Tlx2 and Nkx3.1-Nkx2.6, which do not seem to be coexpressed, are also not associated with conserved noncoding sequences, suggesting that an alternative mechanism may be responsible for the continued clustering of these genes.

High-Resolution Genome-Wide Linkage Mapping Identifies Susceptibility Loci for BMI in the Chinese Population

DEFF Research Database (Denmark)

Zhang, Dong Feng; Pang, Zengchang; Li, Shuxia

2012-01-01

The genetic loci affecting the commonly used BMI have been intensively investigated using linkage approaches in multiple populations. This study aims at performing the first genome-wide linkage scan on BMI in the Chinese population in mainland China with hypothesis that heterogeneity in genetic...... linkage could exist in different ethnic populations. BMI was measured from 126 dizygotic twins in Qingdao municipality who were genotyped using high-resolution Affymetrix Genome-Wide Human SNP arrays containing about 1 million single-nucleotide polymorphisms (SNPs). Nonparametric linkage analysis...... in western countries. Multiple loci showing suggestive linkage were found on chromosome 1 (lod score 2.38 at 242 cM), chromosome 8 (2.48 at 95 cM), and chromosome 14 (2.2 at 89.4 cM). The strong linkage identified in the Chinese subjects that is consistent with that found in populations of European origin...

Strike-slip tectonics during rift linkage

Science.gov (United States)

Pagli, C.; Yun, S. H.; Ebinger, C.; Keir, D.; Wang, H.

2017-12-01

The kinematics of triple junction linkage and the initiation of transforms in magmatic rifts remain debated. Strain patterns from the Afar triple junction provide tests of current models of how rifts grow to link in area of incipient oceanic spreading. Here we present a combined analysis of seismicity, InSAR and GPS derived strain rate maps to reveal that the plate boundary deformation in Afar is accommodated primarily by extensional tectonics in the Red Sea and Gulf of Aden rifts, and does not require large rotations about vertical axes (bookshelf faulting). Additionally, models of stress changes and seismicity induced by recent dykes in one sector of the Afar triple junction provide poor fit to the observed strike-slip earthquakes. Instead we explain these patterns as rift-perpendicular shearing at the tips of spreading rifts where extensional strains terminate against less stretched lithosphere. Our results demonstrate that rift-perpendicular strike-slip faulting between rift segments achieves plate boundary linkage during incipient seafloor spreading.

HIV-1 transmission linkage in an HIV-1 prevention clinical trial

Energy Technology Data Exchange (ETDEWEB)

Leitner, Thomas [Los Alamos National Laboratory; Campbell, Mary S [UNIV OF WASHINGTON; Mullins, James I [UNIV OF WASHINGTON; Hughes, James P [UNIV OF WASHINGTON; Wong, Kim G [UNIV OF WASHINGTON; Raugi, Dana N [UNIV OF WASHINGTON; Scrensen, Stefanie [UNIV OF WASHINGTON

2009-01-01

HIV-1 sequencing has been used extensively in epidemiologic and forensic studies to investigate patterns of HIV-1 transmission. However, the criteria for establishing genetic linkage between HIV-1 strains in HIV-1 prevention trials have not been formalized. The Partners in Prevention HSV/HIV Transmission Study (ClinicaITrials.gov NCT00194519) enrolled 3408 HIV-1 serodiscordant heterosexual African couples to determine the efficacy of genital herpes suppression with acyclovir in reducing HIV-1 transmission. The trial analysis required laboratory confirmation of HIV-1 linkage between enrolled partners in couples in which seroconversion occurred. Here we describe the process and results from HIV-1 sequencing studies used to perform transmission linkage determination in this clinical trial. Consensus Sanger sequencing of env (C2-V3-C3) and gag (p17-p24) genes was performed on plasma HIV-1 RNA from both partners within 3 months of seroconversion; env single molecule or pyrosequencing was also performed in some cases. For linkage, we required monophyletic clustering between HIV-1 sequences in the transmitting and seroconverting partners, and developed a Bayesian algorithm using genetic distances to evaluate the posterior probability of linkage of participants sequences. Adjudicators classified transmissions as linked, unlinked, or indeterminate. Among 151 seroconversion events, we found 108 (71.5%) linked, 40 (26.5%) unlinked, and 3 (2.0%) to have indeterminate transmissions. Nine (8.3%) were linked by consensus gag sequencing only and 8 (7.4%) required deep sequencing of env. In this first use of HIV-1 sequencing to establish endpoints in a large clinical trial, more than one-fourth of transmissions were unlinked to the enrolled partner, illustrating the relevance of these methods in the design of future HIV-1 prevention trials in serodiscordant couples. A hierarchy of sequencing techniques, analysis methods, and expert adjudication contributed to the linkage

Meta-analysis of genome-wide linkage scans of attention deficit hyperactivity disorder

NARCIS (Netherlands)

Zhou, K.; Dempfle, A.; Arcos-Burgos, M.; Bakker, S.C.; Banaschewski, T.; Biederman, J; Buitelaar, J.K.; Castellanos, F.X.; Doyle, A.; Ebstein, R.; Ekholm, J.; Forabosco, P.; Franke, F.; Freitag, C.; Friedel, S.; Gill, M.; Hebebrand, J.; Hinney, A.; Jacob, C.; Lesch, K.P.; Loo, S.K.; Lopera, F.; McCracken, J.T.; McGough, J.J.; Meyer, J.; Mick, E.; Miranda, A.; Muenkel, M.; Mulas, F.; Nelson, S.F.; Nguyen, T.T.; Oades, R.D.; Ogdie, M.N.; Palacio, J.D.; Pineda, D.; Reif, A.; Renner, T.J.; Roeyers, H.; Romanos, M.; Rothenberger, A.; Schäfer, H.; Sergeant, J.A.; Sinke, R.J.; Smalley, S.L.; Sonuga-Barke, E.; Steinhausen, H.C.; van der Meulen, E.; Walitza, S.; Warnke, A.; Lewis, C.M.; Faraone, S.V.; Asherson, P.

2008-01-01

Genetic contribution to the development of attention deficit hyperactivity disorder (ADHD) is well established. Seven independent genome-wide linkage scans have been performed to map loci that increase the risk for ADHD. Although significant linkage signals were identified in some of the studies,

Meta-analysis of genome-wide linkage scans of attention deficit hyperactivity disorder.

NARCIS (Netherlands)

Zhou, K.; Dempfle, A.; Arcos-Burgos, M.; Bakker, S.C.; Banaschewski, T.; Biederman, J.; Buitelaar, J.K.; Castellanos, F.X.; Doyle, A.; Ebstein, R.P.; Ekholm, J.; Forabosco, P.; Franke, B.; Freitag, C.; Friedel, S.; Gill, M.; Hebebrand, J.; Hinney, A.; Jacob, C.; Lesch, K.P.; Loo, S.K.; Lopera, F.; McCracken, J.T.; McGough, J.J.; Meyer, J.; Mick, E.; Miranda, A.; Muenke, M.; Mulas, F.; Nelson, S.F.; Nguyen, T.T.; Oades, R.D.; Ogdie, M.N.; Palacio, J.D.; Pineda, D.; Reif, A.; Renner, T.J.; Roeyers, H.; Romanos, M.; Rothenberger, A.; Schafer, H.; Sergeant, J.A.; Sinke, R.J.; Smalley, S.L.; Sonuga-Barke, E.J.S.; Steinhausen, H.C.; Meulen, E. van der; Walitza, S.; Warnke, A.; Lewis, C.M.; Faraone, S.V.; Asherson, P.

2008-01-01

Genetic contribution to the development of attention deficit hyperactivity disorder (ADHD) is well established. Seven independent genome-wide linkage scans have been performed to map loci that increase the risk for ADHD. Although significant linkage signals were identified in some of the studies,

Analysis of Linkage Effects among Currency Networks Using REER Data

Directory of Open Access Journals (Sweden)

Haishu Qiao

2015-01-01

Full Text Available We modeled the currency networks through the use of REER (real effective exchange rate instead of a bilateral exchange rate in order to overcome the confusion in selecting base currencies. Based on the MST (minimum spanning tree approach and the rolling-window method, we constructed time-varying and correlation-based networks with which we investigate the linkage effects among different currencies. In particular, and as the source of empirical data, we chose the monthly REER data for a set of 61 major currencies during the period from 1994 to 2014. The study demonstrated that obvious linkage effects existed among currency networks and the euro (EUR was confirmed as the predominant world currency. Additionally, we used the rolling-window method to investigate the stability of linkage effects, doing so by calculating the mean correlations and mean distances as well as the normalized tree length and degrees of those currencies. The results showed that financial crises during the study period had a great effect on the currency network’s topology structure and led to more clustered currency networks. Our results suggested that it is more appropriate to estimate the linkage effects among currency networks through the use of REER data.

Single Nucleotide Polymorphism Identification, Characterization, and Linkage Mapping in Quinoa

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P. J. Maughan

2012-11-01

Full Text Available Quinoa ( Willd. is an important seed crop throughout the Andean region of South America. It is important as a regional food security crop for millions of impoverished rural inhabitants of the Andean Altiplano (high plains. Efforts to improve the crop have led to an increased focus on genetic research. We report the identification of 14,178 putative single nucleotide polymorphisms (SNPs using a genomic reduction protocol as well as the development of 511 functional SNP assays. The SNP assays are based on KASPar genotyping chemistry and were detected using the Fluidigm dynamic array platform. A diversity screen of 113 quinoa accessions showed that the minor allele frequency (MAF of the SNPs ranged from 0.02 to 0.50, with an average MAF of 0.28. Structure analysis of the quinoa diversity panel uncovered the two major subgroups corresponding to the Andean and coastal quinoa ecotypes. Linkage mapping of the SNPs in two recombinant inbred line populations produced an integrated linkage map consisting of 29 linkage groups with 20 large linkage groups, spanning 1404 cM with a marker density of 3.1 cM per SNP marker. The SNPs identified here represent important genomic tools needed in emerging plant breeding programs for advanced genetic analysis of agronomic traits in quinoa.

Impact of the Hepatitis Testing and Linkage to Care (HepTLC) Initiative on Linkage to Care for Minnesota Refugees with Hepatitis B, 2012-2014.

Science.gov (United States)

Linde, Ann C; Sweet, Kristin A; Nelson, Kailey; Mamo, Blain; Chute, Sara M

2016-01-01

The Hepatitis Testing and Linkage to Care (HepTLC) initiative promoted viral hepatitis B and hepatitis C screening, posttest counseling, and linkage to care at 34 U.S. sites from 2012 to 2014. Through the HepTLC initiative, the Minnesota Department of Health (MDH) and clinic partners began conducting linkage-to-care activities with hepatitis B-positive refugees in October 2012. This intervention provided culturally appropriate support to link refugees to follow-up care for hepatitis B. MDH refugee health and viral hepatitis surveillance programs, along with clinics that screened newly arrived refugees in Hennepin and Ramsey counties in Minnesota, collaborated on the project, which took place from October 1, 2012, through September 30, 2014. Bilingual care navigators contacted refugees to provide education, make appointments, and arrange transportation. We compared the linkage-to-care rate for participants with the rates for refugees screened the year before project launch using a two-sample test of proportions. In the year preceding the project (October 2011 through September 2012), 87 newly arrived refugees had a positive hepatitis B surface antigen (HBsAg) test. Fifty-six (64%) refugees received follow-up care, 12 (14%) refugees did not receive follow-up care, and 19 (22%) refugees could not be located and had no record of follow-up care. During the project, 174 HBsAg-positive, newly arrived refugees were screened. Of those 174 refugees, 162 (93%) received follow-up care, seven (4%) did not receive follow-up care, and five (3%) could not be located and had no record of follow-up care. The one-year linkage-to-care rate for project participants (93%) was significantly higher than the rate for refugees screened the previous year (64%) (prefugees.

Bioaccumulation and trophic transfer of perfluorinated compounds in a eutrophic freshwater food web

International Nuclear Information System (INIS)

Xu, Jian; Guo, Chang-Sheng; Zhang, Yuan; Meng, Wei

2014-01-01

In this study, the bioaccumulation of perfluorinated compounds from a food web in Taihu Lake in China was investigated. The organisms included egret bird species, carnivorous fish, omnivorous fish, herbivorous fish, zooplankton, phytoplankton, zoobenthos and white shrimp. Isotope analysis by δ 13 C and δ 15 N indicated that the carnivorous fish and egret were the top predators in the studied web, occupying trophic levels intermediate between 3.66 and 4.61, while plankton was at the lowest trophic level. Perfluorinated carboxylates (PFCAs) with 9–12 carbons were significantly biomagnified, with trophic magnification factors (TMFs) ranging from 2.1 to 3.7. The TMF of perfluorooctane sulfonate (PFOS) (2.9) was generally comparable to or lower than those of the PFCAs in the same food web. All hazard ratio (HR) values reported for PFOS and perfluorooctanoate (PFOA) were less than unity, suggesting that the detected levels would not cause any immediate health effects to the people in Taihu Lake region through the consumption of shrimps and fish. -- Highlights: • Biomagnification of PFCs in the food web of a eutrophic freshwater lake was studied. • Carnivorous fish and egret were the top predators while plankton was at the lowest trophic level. • PFCAs with 9–12 carbons were significantly biomagnified. • TMF of PFOS was comparable to or lower than those of the PFCAs in the same food web. • PFOS and PFOA would not cause health effects to the people via diet consumption. -- PFCs were found to be bioaccumulated and biomagnified in a food web from a eutrophic freshwater lake in subtropical area

Learning Expressive Linkage Rules for Entity Matching using Genetic Programming

OpenAIRE

Isele, Robert

2013-01-01

A central problem in data integration and data cleansing is to identify pairs of entities in data sets that describe the same real-world object. Many existing methods for matching entities rely on explicit linkage rules, which specify how two entities are compared for equivalence. Unfortunately, writing accurate linkage rules by hand is a non-trivial problem that requires detailed knowledge of the involved data sets. Another important issue is the efficient execution of link...

Dual-Routine HCV/HIV Testing: Seroprevalence and Linkage to Care in Four Community Health Centers in Philadelphia, Pennsylvania.

Science.gov (United States)

Coyle, Catelyn; Kwakwa, Helena

2016-01-01

Despite common risk factors, screening for hepatitis C virus (HCV) and HIV at the same time as part of routine medical care (dual-routine HCV/HIV testing) is not commonly implemented in the United States. This study examined improvements in feasibility of implementation, screening increase, and linkage to care when a dual-routine HCV/HIV testing model was integrated into routine primary care. National Nursing Centers Consortium implemented a dual-routine HCV/HIV testing model at four community health centers in Philadelphia, Pennsylvania, on September 1, 2013. Routine HCV and opt-out HIV testing replaced the routine HCV and opt-in HIV testing model through medical assistant-led, laboratory-based testing and electronic medical record modification to prompt, track, report, and facilitate reimbursement for tests performed on uninsured individuals. This study examined testing, seropositivity, and linkage-to-care comparison data for the nine months before (December 1, 2012-August 31, 2013) and after (September 1, 2013-May 31, 2014) implementation of the dual-routine HCV/HIV testing model. A total of 1,526 HCV and 1,731 HIV tests were performed before, and 1,888 HCV and 3,890 HIV tests were performed after dual-routine testing implementation, resulting in a 23.7% increase in HCV tests and a 124.7% increase in HIV tests. A total of 70 currently HCV-infected and four new HIV-seropositive patients vs. 101 HCV-infected and 13 new HIV-seropositive patients were identified during these two periods, representing increases of 44.3% for HCV antibody-positive and RNA-positive tests and 225.0% for HIV-positive tests. Linkage to care increased from 27 currently infected HCV--positive and one HIV-positive patient pre-dual-routine testing to 39 HCV--positive and nine HIV-positive patients post-dual-routine testing. The dual-routine HCV/HIV testing model shows that integrating dual-routine testing in a primary care setting is possible and leads to increased HCV and HIV screening

Using the Bootstrap to Account for Linkage Errors when Analysing Probabilistically Linked Categorical Data

Directory of Open Access Journals (Sweden)

Chipperfield James O.

2015-09-01

Full Text Available Record linkage is the act of bringing together records that are believed to belong to the same unit (e.g., person or business from two or more files. Record linkage is not an error-free process and can lead to linking a pair of records that do not belong to the same unit. This occurs because linking fields on the files, which ideally would uniquely identify each unit, are often imperfect. There has been an explosion of record linkage applications, particularly involving government agencies and in the field of health, yet there has been little work on making correct inference using such linked files. Naively treating a linked file as if it were linked without errors can lead to biased inferences. This article develops a method of making inferences for cross tabulated variables when record linkage is not an error-free process. In particular, it develops a parametric bootstrap approach to estimation which can accommodate the sophisticated probabilistic record linkage techniques that are widely used in practice (e.g., 1-1 linkage. The article demonstrates the effectiveness of this method in a simulation and in a real application.

Seasonal hypoxia in eutrophic stratified coastal shelves: mechanisms, sensibilities and interannual variability from the North-Western Black Sea case

Science.gov (United States)

Capet, A.; Beckers, J.-M.; Grégoire, M.

2012-12-01

The Black Sea north-western shelf (NWS) is a~shallow eutrophic area in which seasonal stratification of the water column isolates bottom waters from the atmosphere and prevents ventilation to compensate for the large consumption of oxygen, due to respiration in the bottom waters and in the sediments. A 3-D coupled physical biogeochemical model is used to investigate the dynamics of bottom hypoxia in the Black Sea NWS at different temporal scales from seasonal to interannual (1981-2009) and to differentiate the driving factors (climatic versus eutrophication) of hypoxic conditions in bottom waters. Model skills are evaluated by comparison with 14 500 in-situ oxygen measurements available in the NOAA World Ocean Database and the Black Sea Commission data. The choice of skill metrics and data subselections orientate the validation procedure towards specific aspects of the oxygen dynamics, and prove the model's ability to resolve the seasonal cycle and interannual variability of oxygen concentration as well as the spatial location of the oxygen depleted waters and the specific threshold of hypoxia. During the period 1981-2009, each year exhibits seasonal bottom hypoxia at the end of summer. This phenomenon essentially covers the northern part of the NWS, receiving large inputs of nutrients from the Danube, Dniestr and Dniepr rivers, and extends, during the years of severe hypoxia, towards the Romanian Bay of Constanta. In order to explain the interannual variability of bottom hypoxia and to disentangle its drivers, a statistical model (multiple linear regression) is proposed using the long time series of model results as input variables. This statistical model gives a general relationship that links the intensity of hypoxia to eutrophication and climate related variables. The use of four predictors allows to reproduce 78% of hypoxia interannual variability: the annual nitrate discharge (N), the sea surface temperature in the month preceding stratification (T), the

A Record Linkage Protocol for a Diabetes Registry at Ethnically Diverse Community Health Centers

OpenAIRE

Maizlish, Neil A.; Herrera, Linda

2005-01-01

Community health centers serve ethnically diverse populations that may pose challenges for record linkage based on name and date of birth. The objective was to identify an optimal deterministic algorithm to link patient encounters and laboratory results for hemoglobin A1c testing and examine its variability by health center site, patient ethnicity, and other variables. Based on data elements of last name, first name, date of birth, gender, and health center site, matches with ≥50% to < 100% o...

Data linkage in an established longitudinal cohort: the Western Australian Pregnancy Cohort (Raine) Study.

Science.gov (United States)

Mountain, Jenny A; Nyaradi, Anett; Oddy, Wendy H; Glauert, Rebecca A; de Klerk, Nick H; Straker, Leon M; Stanley, Fiona J

2016-07-15

The Western Australian Data Linkage System is one of a few comprehensive, population-based data linkage systems worldwide, creating links between information from different sources relating to the same individual, family, place or event, while maintaining privacy. The Raine Study is an established cohort study with more than 2000 currently active participants. Individual consent was obtained from participants for information in publicly held databases to be linked to their study data. A waiver of consent was granted where it was impracticable to obtain consent. Approvals to link the datasets were obtained from relevant ethics committees and data custodians. The Raine Study dataset was subsequently linked to academic testing data collected by the Western Australian Department of Education. Examination of diet and academic performance showed that children who were predominantly breastfed for at least 6 months scored higher academically at age 10 than children who were breastfed for less than 6 months. A further study found that better diet quality at ages 1, 2 and 3 years was associated with higher academic scores at ages 10 and 12 years. Examination of nutritional intake at 14 years of age found that a better dietary pattern was associated with higher academic performance. The detailed longitudinal data collected in the Raine Study allowed for adjustment for multiple covariates and confounders. Data linkage reduces the burden on cohort participants by providing additional information without the need to contact participants. It can give information on participants who have been lost to follow-up; provide or complement missing data; give the opportunity for validation studies comparing recall of participants with administrative records; increase the population sample of studies by adding control participants from the general population; and allow for the adjustment of multiple covariates and confounders. The Raine Study dataset is extensive and detailed, and can be

Saturation of an intra-gene pool linkage map: towards a unified consensus linkage map for fine mapping and synteny analysis in common bean.

Science.gov (United States)

Galeano, Carlos H; Fernandez, Andrea C; Franco-Herrera, Natalia; Cichy, Karen A; McClean, Phillip E; Vanderleyden, Jos; Blair, Matthew W

2011-01-01

Map-based cloning and fine mapping to find genes of interest and marker assisted selection (MAS) requires good genetic maps with reproducible markers. In this study, we saturated the linkage map of the intra-gene pool population of common bean DOR364 × BAT477 (DB) by evaluating 2,706 molecular markers including SSR, SNP, and gene-based markers. On average the polymorphism rate was 7.7% due to the narrow genetic base between the parents. The DB linkage map consisted of 291 markers with a total map length of 1,788 cM. A consensus map was built using the core mapping populations derived from inter-gene pool crosses: DOR364 × G19833 (DG) and BAT93 × JALO EEP558 (BJ). The consensus map consisted of a total of 1,010 markers mapped, with a total map length of 2,041 cM across 11 linkage groups. On average, each linkage group on the consensus map contained 91 markers of which 83% were single copy markers. Finally, a synteny analysis was carried out using our highly saturated consensus maps compared with the soybean pseudo-chromosome assembly. A total of 772 marker sequences were compared with the soybean genome. A total of 44 syntenic blocks were identified. The linkage group Pv6 presented the most diverse pattern of synteny with seven syntenic blocks, and Pv9 showed the most consistent relations with soybean with just two syntenic blocks. Additionally, a co-linear analysis using common bean transcript map information against soybean coding sequences (CDS) revealed the relationship with 787 soybean genes. The common bean consensus map has allowed us to map a larger number of markers, to obtain a more complete coverage of the common bean genome. Our results, combined with synteny relationships provide tools to increase marker density in selected genomic regions to identify closely linked polymorphic markers for indirect selection, fine mapping or for positional cloning.

Do lake littoral benthic invertebrates respond differently to eutrophication, hydromorphological alteration, land use and fish stocking?

Directory of Open Access Journals (Sweden)

Šiling Rebeka

2016-01-01

Full Text Available In order to provide adequate guidelines in freshwater management, managers need reliable bioindicators that can respond differently to varied stressors. Managers also have to consider hierarchical structure of environmental factors. Thus, our research aims to test the independence of taxa responses along environmental gradients and to examine in what order natural and anthropogenic factors constrain the structure of littoral benthic assemblages. The rank of explained variance of littoral benthic assemblage's variable group hierarchy was: land use > landscape characteristics > eutrophication > fish stocking > hydromorphological alteration. We determined nine gradients (two natural and seven stressor gradients, separated into five groups based on statistically significant differences in responsiveness of taxa. Apart from responsiveness to natural factors, littoral benthic invertebrates could be used as bioindicators for stressors reflecting urbanization, eutrophication, hydromorphological alteration and fish stocking. The taxonomical composition of littoral benthic invertebrates, especially when taxa with preference for certain relatively narrow environmental conditions along gradients are present, can be used to identify effects of key stressors. Our findings have profound implications for ecological assessment and management of lakes, as they indicate that benthic invertebrates can be used when the effects of multiple stressors need to be disentangled.

Eutrophic lichens respond to multiple forms of N: implications for critical levels and critical loads research

Science.gov (United States)

Sarah Jovan; Jennifer Riddell; Pamela E Padgett; Thomas Nash

2012-01-01

Epiphytic lichen communities are highly sensitive to excess nitrogen (N), which causes the replacement of native floras by N-tolerant, ‘‘weedy’’ eutrophic species. This shift is commonly used as the indicator of ecosystem ‘‘harm’’ in studies developing empirical critical levels (CLE) for ammonia (NH3) and critical loads (CLO) for N. To be most...

'Linkage' pharmaceutical evergreening in Canada and Australia

Science.gov (United States)

Faunce, Thomas A; Lexchin, Joel

2007-01-01

'Evergreening' is not a formal concept of patent law. It is best understood as a social idea used to refer to the myriad ways in which pharmaceutical patent owners utilise the law and related regulatory processes to extend their high rent-earning intellectual monopoly privileges, particularly over highly profitable (either in total sales volume or price per unit) 'blockbuster' drugs. Thus, while the courts are an instrument frequently used by pharmaceutical brand name manufacturers to prolong their patent royalties, 'evergreening' is rarely mentioned explicitly by judges in patent protection cases. The term usually refers to threats made to competitors about a brand-name manufacturer's tactical use of pharmaceutical patents (including over uses, delivery systems and even packaging), not to extension of any particular patent over an active product ingredient. This article focuses in particular on the 'evergreening' potential of so-called 'linkage' provisions, imposed on the regulatory (safety, quality and efficacy) approval systems for generic pharmaceuticals of Canada and Australia, by specific articles in trade agreements with the US. These 'linkage' provisions have also recently appeared in the Korea-US Free Trade Agreement (KORUSFTA). They require such drug regulators to facilitate notification of, or even prevent, any potential patent infringement by a generic pharmaceutical manufacturer. This article explores the regulatory lessons to be learnt from Canada's and Australia's shared experience in terms of minimizing potential adverse impacts of such 'linkage evergreening' provisions on drug costs and thereby potentially on citizen's access to affordable, essential medicines. PMID:17543113

Linkage to HIV care and antiretroviral therapy in Cape Town, South Africa.

Directory of Open Access Journals (Sweden)

Katharina Kranzer

2010-11-01

Full Text Available Antiretroviral therapy (ART has been scaled-up rapidly in Africa. Programme reports typically focus on loss to follow-up and mortality among patients receiving ART. However, little is known about linkage and retention in care of individuals prior to starting ART.Data on adult residents from a periurban community in Cape Town were collected at a primary care clinic and hospital. HIV testing registers, CD4 count results provided by the National Health Laboratory System and ART registers were linked. A random sample (n = 885 was drawn from adults testing HIV positive through antenatal care, sexual transmitted disease and voluntary testing and counseling services between January 2004 and March 2009. All adults (n = 103 testing HIV positive through TB services during the same time period were also included in the study. Linkage to HIV care was defined as attending for a CD4 count measurement within 6 months of HIV diagnosis. Linkage to ART care was defined as initiating ART within 6 months of HIV diagnosis in individuals with a CD4 count ≤200 cells/µl taken within 6 months of HIV diagnosis.Only 62.6% of individuals attended for a CD4 count measurement within 6 months of testing HIV positive. Individuals testing through sexually transmitted infection services had the best (84.1% and individuals testing on their own initiative (53.5% the worst linkage to HIV care. One third of individuals with timely CD4 counts were eligible for ART and 66.7% of those were successfully linked to ART care. Linkage to ART care was highest among antenatal care clients. Among individuals not yet eligible for ART only 46.3% had a repeat CD4 count. Linkage to HIV care improved in patients tested in more recent calendar period.Linkage to HIV and ART care was low in this poor peri-urban community despite free services available within close proximity. More efforts are needed to link VCT scale-up to subsequent care.

Cytogenetical anchoring of sheep linkage map and syntenic groups using a sheep BAC library

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Cribiu Edmond-Paul

2000-07-01

Full Text Available Abstract In order to simultaneously integrate linkage and syntenic groups to the ovine chromosomal map, a sheep bacterial artificial chromosome (BAC library was screened with previously assigned microsatellites using a sheep-hamster hybrid panel and genetic linkage. Thirty-three BACs were obtained, fluorescently labelled and hybridised on sheep-goat hybrid metaphases (2n = 57. This study allowed us, (i, to anchor all linkage groups on sheep chromosomes, (ii, to give information on the probable position of the centromere on the linkage map for the centromeric chromosomes, (iii, to contradict the previous orientation of the ovine × linkage group by the mapping of BMS1008 on OARXq38. Concerning our somatic cell hybrid panel, this study resulted in the assignment of all the previously unassigned groups to ovine chromosomes and a complete characterisation of the hybrid panel. In addition, since hybridisations were performed on a sheep-goat hybrid, new marker/anchoring points were added to the caprine cytogenetic map.

Effects of submerged macrophytes on the abundance and community composition of ammonia-oxidizing prokaryotes in a eutrophic lake.

Science.gov (United States)

Zhao, Da-yong; Luo, Juan; Zeng, Jin; Wang, Meng; Yan, Wen-ming; Huang, Rui; Wu, Qinglong L

2014-01-01

Abundances and community compositions of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in unvegetated sediment and the rhizosphere sediments of three submerged macrophytes (Ceratophyllum demersum, Vallisneria spinulosa, and Potamogeton crispus) were investigated in a large, eutrophic freshwater lake, Lake Taihu. Abundances of archaeal ammonia monooxygenase alpha-subunit (amoA) gene (from 6.56 × 10(6) copies to 1.06 × 10(7) copies per gram of dry sediment) were higher than those of bacterial amoA (from 6.13 × 10(5) to 3.21 × 10(6) copies per gram of dry sediment) in all samples. Submerged macrophytes exhibited no significant effect on the abundance and diversity of archaeal amoA gene. C. demersum and V. spinulosa increased the abundance and diversity of bacterial amoA gene in their rhizosphere sediment. However, the diversity of bacterial amoA gene in the rhizosphere sediments of P. crispus was decreased. The data obtained in this study would be helpful to elucidate the roles of submerged macrophytes involved in the nitrogen cycling of eutrophic lake ecosystems.

Clinical and genetic linkage analysis of a large Venezuelan kindred with Usher syndrome.

Science.gov (United States)

Keogh, Ivan J; Godinho, R N; Wu, T Po; Diaz de Palacios, A M; Palacios, N; Bello de Alford, M; De Almada, M I; MarPalacios, N; Vazquez, A; Mattei, R; Seidman, C; Seidman, J; Eavey, R D

2004-08-01

To undertake a comprehensive investigation into the very high incidence of congenital deafness on the Macano peninsula of Margarita Island, Venezuela. Numerous visits were made to the isolated island community over a 4-year-period. During these visits, it became apparent that a significant number of individuals complained of problems with hearing and vision. Socioeconomic assessments, family pedigrees and clinical histories were recorded on standard questionnaires. All individuals underwent thorough otolaryngologic and ophthalmologic examinations. Twenty milliliters of peripheral venous blood was obtained from each participant. A genome-wide linkage analysis study was performed. Polymorphic microsatellite markers were amplified by polymerase chain reaction and separated on polyacrylamide gels. An ABI 377XL sequencer was used to separate fragments and LOD scores were calculated by using published software. Twenty-four families were identified, comprising 329 individuals, age range 1-80 years, including 184 children. All families were categorized in the lower two (least affluent) socioeconomic categories. A high incidence of consanguinity was detected. Fifteen individuals (11 adults, 4 children) had profound congenital sensorineural hearing loss, vestibular areflexia and retinitis pigmentosa. A maximum LOD score of 6.76 (Linkage >3.0), between markers D11s4186 and D11s911, confirmed linkage to chromosome 11q13.5. The gene myosin VIIA (MYO7A) was confirmed in the interval. Clinical and genetic findings are consistent with a diagnosis of Usher syndrome 1B for those with hearing and vision problems. We report 15 Usher syndrome 1B individuals from a newly detected Latin American socio-demographic origin, with a very high prevalence of 76 per 100,000 population.

Broad scan linkage analysis in a large Tourette family pedigree

Energy Technology Data Exchange (ETDEWEB)

Peiffer, A.; Leppert, M. [Univ. of Utah Health Sciences Center, Salt Lake City, UT (United States); Wetering, B.J.M. van der [Univ. Hospital Rotterdam (Netherlands)

1994-09-01

Attempts to find a gene causing Tourette syndrome (TS) using linkage analysis have been unsuccessful even though as much as 65% of the autosomal genetic map has been excluded by the pooled results from several laboratories collaborating worldwide. One reason for this failure may be the misclassification of affection status of marry-in spouses. Specifically, we have found that six unrelated spouses in our Utah TS pedigree suffer from TS, obsessive-compulsive disorder or chronic motor tics. In light of these findings we decided to conduct a complete genomic scan from this Utah kindred with polymorphic markers in three related sibships in which there was no assortative mating. A linkage study assuming autosomal dominant inheritance was done using tetranucleotide repeat markers developed at the University of Utah. We selected markers that were less than 300 bp in size and that gave a heterozygosity of over 70% upon analysis in 4 CEPH families. Results to date with 95 markers run at an interval of 30 cM (covering 61% of the genome) show no evidence of linkage. We intend to extend the coverage to 100% of the genome. Pending completion of this scan, failure to provide evidence of linkage in our TS pedigree might then be attributed to phenotypic misclassification or erroneous assumptions regarding the genetic model of transmission.

Impact of the Hepatitis Testing and Linkage to Care (HepTLC) Initiative on Linkage to Care for Minnesota Refugees with Hepatitis B, 2012–2014

Science.gov (United States)

Sweet, Kristin A.; Nelson, Kailey; Mamo, Blain; Chute, Sara M.

2016-01-01

Objective The Hepatitis Testing and Linkage to Care (HepTLC) initiative promoted viral hepatitis B and hepatitis C screening, posttest counseling, and linkage to care at 34 U.S. sites from 2012 to 2014. Through the HepTLC initiative, the Minnesota Department of Health (MDH) and clinic partners began conducting linkage-to-care activities with hepatitis B-positive refugees in October 2012. This intervention provided culturally appropriate support to link refugees to follow-up care for hepatitis B. Methods MDH refugee health and viral hepatitis surveillance programs, along with clinics that screened newly arrived refugees in Hennepin and Ramsey counties in Minnesota, collaborated on the project, which took place from October 1, 2012, through September 30, 2014. Bilingual care navigators contacted refugees to provide education, make appointments, and arrange transportation. We compared the linkage-to-care rate for participants with the rates for refugees screened the year before project launch using a two-sample test of proportions. Results In the year preceding the project (October 2011 through September 2012), 87 newly arrived refugees had a positive hepatitis B surface antigen (HBsAg) test. Fifty-six (64%) refugees received follow-up care, 12 (14%) refugees did not receive follow-up care, and 19 (22%) refugees could not be located and had no record of follow-up care. During the project, 174 HBsAg-positive, newly arrived refugees were screened. Of those 174 refugees, 162 (93%) received follow-up care, seven (4%) did not receive follow-up care, and five (3%) could not be located and had no record of follow-up care. The one-year linkage-to-care rate for project participants (93%) was significantly higher than the rate for refugees screened the previous year (64%) (prefugees. PMID:27168670

Allele-sharing models: LOD scores and accurate linkage tests.

Science.gov (United States)

Kong, A; Cox, N J

1997-11-01

Starting with a test statistic for linkage analysis based on allele sharing, we propose an associated one-parameter model. Under general missing-data patterns, this model allows exact calculation of likelihood ratios and LOD scores and has been implemented by a simple modification of existing software. Most important, accurate linkage tests can be performed. Using an example, we show that some previously suggested approaches to handling less than perfectly informative data can be unacceptably conservative. Situations in which this model may not perform well are discussed, and an alternative model that requires additional computations is suggested.

Water quality in simulated eutrophic shallow lakes in the presence of periphyton under different flow conditions.

Science.gov (United States)

Chen, Shu; Yang, Guolu; Lu, Jing; Wang, Lei

2018-02-01

Although the effects of periphyton on water quality and its relationship with flow conditions have been studied by researchers, our understanding about their combined action in eutrophic shallow lakes is poor. In this research, four aquatic model ecosystems with different water circulation rates and hydraulic conditions were constructed to investigate the effect of periphyton and flow condition on water quality. The concentrations of NH 4 + , TP, and chlorophyll-a and flow conditions were determined. The results show that, as a result of the rising nutrient level at the early stage and the decline in the lower limit, the presence of periphyton can make the ecosystem adaptable to a wider range of nutrients concentration. In terms of the flow condition, the circulation rate and hydraulic condition are influential factors for aquatic ecosystem. Higher circulation rate in the ecosystem, on one hand, facilitates the metabolism by accelerating nutrient cycling which is beneficial to water quality; on the other hand, high circulation rate leads to the nutrient lower limit rising which is harmful to water quality improvement. At low velocities, slight differences in hydraulic conditions, vertical velocity gradient and turbulence intensity gradient could affect the quantity of phytoplankton. Our study suggests that, considering environmental effect of periphyton, flow conditions and their combined action is essential for water quality improvement and ecological restoration in eutrophic shallow lakes.

Linkage of morbid obesity with polymorphic microsatellite markers on chromosome 1q31 in a three-generation Canadian kindred

Energy Technology Data Exchange (ETDEWEB)

Murray, J.D.; Bulman, D.E.; Ebers, G.C. [University Hospital, London (Canada)]|[INSERM, Paris (France)] [and others

1994-09-01

Obesity is the most common nutritional disorder affecting Western societies. An estimated 3.7 million Canadians are considered to be overweight, a condition associated with hypertension, accelerated atherosclerosis, diabetes and a host of other medical problems. We have identified a 3 generation kindred in which morbid obesity appears to segregate in an autosomal dominant manner. All individuals were examined. Mass (kg) and heights (m) were measured in order to determine a body mass index (BMI) for each individual. Those individuals with BMI of greater than or equal to 30.0 were designated as affected. In the pedigree studied 25 individuals met this criteria and 12 of these were morbidly obese (BMI greater or equal to 40.0). A search of candidate genes proved unfruitful. A linkage study was initiated. All individuals in the pedigree were genotyped for microsatellite markers which were spaced every 20 centimorgans (cM). Positive evidence of linkage was detected with markers which map to 1q31-32 (lod score of 3.6 at {theta} = 0.05). Notably, strong effects for fatness in pigs have been found on pig chromosome 4 which has synteny with human chromosome 1q21-32. We are currently attempting to refine the position of this gene using linkage analysis with other microsatellite markers from this region of the genome. In addition we are screening other families in which obesity segregates for linkage to 1q31.

Parental Perceived Control and Social Support: Linkages to Change in Parenting Behaviors During Early Adolescence.

Science.gov (United States)

Lippold, Melissa A; Glatz, Terese; Fosco, Gregory M; Feinberg, Mark E

2018-06-01

Prior studies have found that parents' perceptions of control over their lives and their social support may both be important for parenting behaviors. Yet, few studies have examined their unique and interacting influence on parenting behaviors during early adolescence. This longitudinal study of rural parents in two-parent families (N = 636) investigated (a) whether perceived control and social support when their youth were in sixth grade were independently or interactively associated with changes in parenting behaviors (discipline, standard setting) and parent-child warmth and hostility 6 months later and (b) if these linkages differed by parent gender. We also investigated the interactive links between perceived control, social support, and parenting. Specifically, we tested if parents' perceived control moderated the linkages between social support and parenting and if these linkages differed by parent gender. Greater perceived control predicted more increases in parents' consistent discipline and standard setting, whereas greater social support predicted increases in parent-child warmth and decreases in parent-child hostility. Parental perceived control moderated the effect of social support on parental warmth: For mothers only, social support was significantly linked to parent-child warmth only when mothers had low (but not high) perceived self-control. The discussion focuses on reasons why perceived control and social support may have associations with different aspects of parenting and why these might differ for mothers and fathers. © 2017 Family Process Institute.

Siblings versus parents and friends: longitudinal linkages to adolescent externalizing problems.

Science.gov (United States)

Defoe, Ivy N; Keijsers, Loes; Hawk, Skyler T; Branje, Susan; Dubas, Judith Semon; Buist, Kirsten; Frijns, Tom; van Aken, Marcel A G; Koot, Hans M; van Lier, Pol A C; Meeus, Wim

2013-08-01

It is well documented that friends' externalizing problems and negative parent-child interactions predict externalizing problems in adolescence, but relatively little is known about the role of siblings. This four-wave, multi-informant study investigated linkages of siblings' externalizing problems and sibling-adolescent negative interactions on adolescents' externalizing problems, while examining and controlling for similar linkages with friends and parents. Questionnaire data on externalizing problems and negative interactions were annually collected from 497 Dutch adolescents (M = 13.03 years, SD = 0.52, at baseline), as well as their siblings, mothers, fathers, and friends. Cross-lagged panel analyses revealed modest unique longitudinal paths from sibling externalizing problems to adolescent externalizing problems, for male and female adolescents, and for same-sex and mixed-sex sibling dyads, but only from older to younger siblings. Moreover, these paths were above and beyond significant paths from mother-adolescent negative interaction and friend externalizing problems to adolescent externalizing problems, 1 year later. No cross-lagged paths existed between sibling-adolescent negative interaction and adolescent externalizing problems. Taken together, it appears that especially older sibling externalizing problems may be a unique social risk factor for adolescent externalizing problems, equal in strength to significant parents' and friends' risk factors. © 2013 The Authors. Journal of Child Psychology and Psychiatry © 2013 Association for Child and Adolescent Mental Health.

Quantitative linkage genome scan for atopy in a large collection of Caucasian families

DEFF Research Database (Denmark)

Webb, BT; van den Oord, E; Akkari, A

2007-01-01

adulthood, asthma is frequently associated also with quantitative measures of atopy. Genome wide quantitative multipoint linkage analysis was conducted for serum IgE levels and percentage of positive skin prick test (SPT(per)) using three large groups of families originally ascertained for asthma....... In this report, 438 and 429 asthma families were informative for linkage using IgE and SPT(per) which represents 690 independent families. Suggestive linkage (LOD >/= 2) was found on chromosomes 1, 3, and 8q with maximum LODs of 2.34 (IgE), 2.03 (SPT(per)), and 2.25 (IgE) near markers D1S1653, D3S2322-D3S1764...... represents one of the biggest genome scans so far reported for asthma related phenotypes. This study also demonstrates the utility of increased sample sizes and quantitative phenotypes in linkage analysis of complex disorders....

Applying Topographic Classification, Based on the Hydrological Process, to Design Habitat Linkages for Climate Change

Directory of Open Access Journals (Sweden)

Yongwon Mo

2017-11-01

Full Text Available The use of biodiversity surrogates has been discussed in the context of designing habitat linkages to support the migration of species affected by climate change. Topography has been proposed as a useful surrogate in the coarse-filter approach, as the hydrological process caused by topography such as erosion and accumulation is the basis of ecological processes. However, some studies that have designed topographic linkages as habitat linkages, so far have focused much on the shape of the topography (morphometric topographic classification with little emphasis on the hydrological processes (generic topographic classification to find such topographic linkages. We aimed to understand whether generic classification was valid for designing these linkages. First, we evaluated whether topographic classification is more appropriate for describing actual (coniferous and deciduous and potential (mammals and amphibians habitat distributions. Second, we analyzed the difference in the linkages between the morphometric and generic topographic classifications. The results showed that the generic classification represented the actual distribution of the trees, but neither the morphometric nor the generic classification could represent the potential animal distributions adequately. Our study demonstrated that the topographic classes, according to the generic classification, were arranged successively according to the flow of water, nutrients, and sediment; therefore, it would be advantageous to secure linkages with a width of 1 km or more. In addition, the edge effect would be smaller than with the morphometric classification. Accordingly, we suggest that topographic characteristics, based on the hydrological process, are required to design topographic linkages for climate change.

Video-conferencing Telehealth Linkage attempts to Schools to Facilitate Mental Health Consultation.

Science.gov (United States)

McLennan, John D

2018-04-01

Telehealth to schools may be a strategic approach to expand child mental health service delivery, however, there are only a few published examples. This report describes video-conferencing telehealth linkage attempts to schools to facilitate mental health consultation. A series of synchronous video-conferencing linkage strategies were attempted to connect a mental health consultation service to multiple schools in a Canadian setting. Consultation to support the implementation of the Daily Report Card, for students with attentional and behavioural problems, was the core content of this pilot linkage attempt. Synchronous video conference consultations were successfully delivered to six elementary schools across three school districts. Two of three linkage strategies were functional. One used existing health centre-based telehealth units to connect to school-based dedicated tablets with a video collaboration app and reliance on existing school Wi-Fi. A second used existing laptops in both the health and school system linked through a communication platform. A third connection, using 3G/4G hotspots to obviate the need to access school Wi-Fi, was deemed too expensive in this setting. The potential to use existing computer hardware to connect mental health providers and schools could facilitate scale-up. However, it is unknown whether mental health systems and school sectors will invest in such linkages and reorganize core mental health services to be delivered in this way.

The dopamine transporter protein gene (SLC6A3): Primary linage mapping and linkage studies in Tourette syndrome

Energy Technology Data Exchange (ETDEWEB)

Gelernter, J.; Kruger, S.D.; Pakstis, A.J. [Yale Univ., New Haven, CT (United States)]|[West Haven Veterans Affairs Medical Center, CT (United States)] [and others

1995-12-10

The dopamine transporter, the molecule responsible for presynaptic reuptake of dopamine and a major site of action of psychostimulant drugs, including cocaine, is encoded by locus SLC6A3 (alias DAT1). The protein`s actions and DAT`s specific localization to dopaminergic neurons make it a candidate gene for several psychiatric illnesses. SLC6A3 has been mapped to distal chromosome 5p, using physical methods. Genetic linkage methods were used to place SLC6A3 in the genetic linkage map. Four extended pedigrees (one of which overlaps with CEPH) were typed. Linkage with Tourette syndrome (TS) was also examined. SLC6A3 showed close linkage with several markers previously mapped to distal chromosome 5p, including D5S11 (Z{sub max} = 16.0, {theta}{sub M} = {theta}{sub F} = 0.03, results from four families) and D5S678 (Z{sub max} = 7.84, {theta}{sub M} = {theta}{sub F} = 0, results from two families). Observed crossovers established that SLC6A3 is a distal marker close to D5S10 and D5S678, but these three distal markers could not be ordered. Linkage between TS and SLC6A3 could be excluded independently in two branches of a large kindred segregating TS; the lod score in a third family was also negative, but not significant. Cumulative results show a lod score of -6.2 at {theta} = 0 and of -3.9 at {theta} = 0.05 (dominant model, narrow disease definition). SLC6A3 thus maps to distal chromosome 5p by linkage analysis, in agreement with previous physical mapping data. A mutation at SLC6A3 is not causative for TS in the two large families that generated significant negative lod scores (if the parameters of our analyses were correct) and is unlikely to be causative in the family that generated a negative lod score that did not reach significance. These results do not exclude a role for the dopamine transporter in influencing risk for TS in combination with other loci. 23 refs., 1 fig., 2 tabs.

Historical measures of social context in life course studies: retrospective linkage of addresses to decennial censuses

Directory of Open Access Journals (Sweden)

Whitsel Eric A

2004-11-01

Full Text Available Abstract Background There is evidence of a contribution of early life socioeconomic exposures to the risk of chronic diseases in adulthood. However, extant studies investigating the impact of the neighborhood social environment on health tend to characterize only the current social environment. This in part may be due to complexities involved in obtaining and geocoding historical addresses. The Life Course Socioeconomic Status, Social Context, and Cardiovascular Disease Study collected information on childhood (1930–1950 and early adulthood (1960–1980 place of residence from 12,681 black and white middle-aged and older men and women from four U.S. communities to link participants with census-based socioeconomic indicators over the life course. Results Most (99% participants were linked to 1930–50 county level socioeconomic census data (the smallest level of aggregation universally available during this time period corresponding to childhood place of residence. Linkage did not vary by race, gender, birth cohort, or level of educational attainment. A commercial geocoding vendor processed participants' self-reported street addresses for ages 30, 40, and 50. For 1970 and 1980 censuses, spatial coordinates were overlaid onto shape files containing census tract boundaries; for 1960 no shape files existed and comparability files were used. Several methods were tested for accuracy and to increase linkage. Successful linkage to historical census tracts varied by census (66% for 1960, 76% for 1970, 85% for 1980. This compares to linkage rates of 94% for current addresses provided by participants over the course of the ARIC examinations. Conclusion There are complexities and limitations in characterizing the past social context. However, our results suggest that it is feasible to characterize the earlier social environment with known levels of measurement error and that such an approach should be considered in future studies.

Direct power comparisons between simple LOD scores and NPL scores for linkage analysis in complex diseases.

Science.gov (United States)

Abreu, P C; Greenberg, D A; Hodge, S E

1999-09-01

Several methods have been proposed for linkage analysis of complex traits with unknown mode of inheritance. These methods include the LOD score maximized over disease models (MMLS) and the "nonparametric" linkage (NPL) statistic. In previous work, we evaluated the increase of type I error when maximizing over two or more genetic models, and we compared the power of MMLS to detect linkage, in a number of complex modes of inheritance, with analysis assuming the true model. In the present study, we compare MMLS and NPL directly. We simulated 100 data sets with 20 families each, using 26 generating models: (1) 4 intermediate models (penetrance of heterozygote between that of the two homozygotes); (2) 6 two-locus additive models; and (3) 16 two-locus heterogeneity models (admixture alpha = 1.0,.7,.5, and.3; alpha = 1.0 replicates simple Mendelian models). For LOD scores, we assumed dominant and recessive inheritance with 50% penetrance. We took the higher of the two maximum LOD scores and subtracted 0.3 to correct for multiple tests (MMLS-C). We compared expected maximum LOD scores and power, using MMLS-C and NPL as well as the true model. Since NPL uses only the affected family members, we also performed an affecteds-only analysis using MMLS-C. The MMLS-C was both uniformly more powerful than NPL for most cases we examined, except when linkage information was low, and close to the results for the true model under locus heterogeneity. We still found better power for the MMLS-C compared with NPL in affecteds-only analysis. The results show that use of two simple modes of inheritance at a fixed penetrance can have more power than NPL when the trait mode of inheritance is complex and when there is heterogeneity in the data set.

Production Cells in Construction: Considering Time, Space and Information Linkages to Seek Broader Implementations

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Renato Nunes Mariz

2013-01-01

Full Text Available The use of production cells in manufacturing has achieved many benefits, motivating researchers to apply them in the construction environment. The aim of this research is to identify time, space, and information linkages in construction’s production cells applications, seeking opportunities for broader implementations. We adopted a literature review approach focusing on cases in the Brazilian construction sector that addressed cell applications. Subsequently, comparative tables of these publications were prepared, analyzing the consideration of time, space, and information linkages, as well as identified results. The article pointed out that there is a gap in publications that address the application of a production cell in almost all construction flows, except the job site flow, reflecting the tendency of most companies of applying lean concepts firstly in physical flows. By analyzing these aspects (group of features that enhance the use of the cell, it was found that “material flow and pull systems” and “operators interaction” were the aspects most often considered, but mostly partially. Few cases reported the use of “flexibility” and “equipment maintenance”. No case reported comprehensive considerations of the three important linkages of time, space, and information. Space was the linkage better considered compared to time and information linkages. Lead time reduction, cost savings and increased productivity were among the greatest benefits reported from the applications of production cells. There is also a positive correlation between the linkages coverage and the number of benefits obtained. Further research is suggested in order to investigate the results of a more comprehensive application considering all linkages.

Effects of simulated eutrophication and overfishing on algae and invertebrate settlement in a coral reef of Koh Phangan, Gulf of Thailand.

Science.gov (United States)

Stuhldreier, Ines; Bastian, Pepe; Schönig, Eike; Wild, Christian

2015-03-15

Coral reefs in the Gulf of Thailand are highly under-investigated regarding responses to anthropogenic stressors. Thus, this study simulated overfishing and eutrophication using herbivore exclosure cages and slow-release fertilizer to study the in-situ effects on benthic algae and invertebrate settlement in a coral reef of Koh Phangan, Thailand. Settlement of organisms and the development of organic matter on light-exposed and shaded tiles were quantified weekly/biweekly over a study period of 12 weeks. Simulated eutrophication did not significantly influence response parameters, while simulated overfishing positively affected dry mass, turf algae height and fleshy macroalgae occurrence on light-exposed tiles. On shaded tiles, settlement of crustose coralline algae decreased, while abundances of ascidians increased compared to controls. An interactive effect of both stressors was not observed. These results hint to herbivory as actual key controlling factor on the benthic community, and fleshy macroalgae together with ascidians as potential bioindicators for local overfishing. Copyright © 2015 Elsevier Ltd. All rights reserved.

Emergent and floating-leaved macrophytes as refuge for zooplankton in a eutrophic temperate lake without submerged vegetation

DEFF Research Database (Denmark)

Cazzanelli, Matteo; Perlt, Trine Warming; Christoffersen, Kirsten Seestern

2008-01-01

Several studies have shown that submerged macrophytes provide a refuge for zooplankton against fish predation, whereas the role of emergent and floating-leaved species, which are often dominant in eutrophic turbid lakes, is far less investigated. Zooplankton density in open water and amongst....... As a consequence, especially in turbid lakes, the ecological role of these functional types of vegetation, and not merely that of submerged macrophyte species, should be taken into consideration....

Linkages between landscapes and human well-being

DEFF Research Database (Denmark)

Bieling, Claudia; Plieninger, Tobias; Pirker, Heidemarie

2014-01-01

in Germany and Austria by performing open, single-question interviews with 262 respondents. Data reveal an outstanding relevance of nonmaterial values. Linkages between landscapes and human well-being are tied to specific features of the material environment but, likewise, practices and experiences play...

Drivers, mechanisms and long-term variability of seasonal hypoxia on the Black Sea northwestern shelf - is there any recovery after eutrophication?

Science.gov (United States)

Capet, A.; Beckers, J.-M.; Grégoire, M.

2013-06-01

The Black Sea northwestern shelf (NWS) is a shallow eutrophic area in which the seasonal stratification of the water column isolates the bottom waters from the atmosphere. This prevents ventilation from counterbalancing the large consumption of oxygen due to respiration in the bottom waters and in the sediments, and sets the stage for the development of seasonal hypoxia. A three-dimensional (3-D) coupled physical-biogeochemical model is used to investigate the dynamics of bottom hypoxia in the Black Sea NWS, first at seasonal and then at interannual scales (1981-2009), and to differentiate its driving factors (climatic versus eutrophication). Model skills are evaluated by a quantitative comparison of the model results to 14 123 in situ oxygen measurements available in the NOAA World Ocean and the Black Sea Commission databases, using different error metrics. This validation exercise shows that the model is able to represent the seasonal and interannual variability of the oxygen concentration and of the occurrence of hypoxia, as well as the spatial distribution of oxygen-depleted waters. During the period 1981-2009, each year exhibits seasonal bottom hypoxia at the end of summer. This phenomenon essentially covers the northern part of the NWS - which receives large inputs of nutrients from the Danube, Dniester and Dnieper rivers - and extends, during the years of severe hypoxia, towards the Romanian bay of Constanta. An index H which merges the aspects of the spatial and temporal extension of the hypoxic event is proposed to quantify, for each year, the intensity of hypoxia as an environmental stressor. In order to explain the interannual variability of H and to disentangle its drivers, we analyze the long time series of model results by means of a stepwise multiple linear regression. This statistical model gives a general relationship that links the intensity of hypoxia to eutrophication and climate-related variables. A total of 82% of the interannual variability

A second-generation anchored genetic linkage map of the tammar wallaby (Macropus eugenii

Directory of Open Access Journals (Sweden)

Patel Hardip R

2011-08-01

Full Text Available Abstract Background The tammar wallaby, Macropus eugenii, a small kangaroo used for decades for studies of reproduction and metabolism, is the model Australian marsupial for genome sequencing and genetic investigations. The production of a more comprehensive cytogenetically-anchored genetic linkage map will significantly contribute to the deciphering of the tammar wallaby genome. It has great value as a resource to identify novel genes and for comparative studies, and is vital for the ongoing genome sequence assembly and gene ordering in this species. Results A second-generation anchored tammar wallaby genetic linkage map has been constructed based on a total of 148 loci. The linkage map contains the original 64 loci included in the first-generation map, plus an additional 84 microsatellite loci that were chosen specifically to increase coverage and assist with the anchoring and orientation of linkage groups to chromosomes. These additional loci were derived from (a sequenced BAC clones that had been previously mapped to tammar wallaby chromosomes by fluorescence in situ hybridization (FISH, (b End sequence from BACs subsequently FISH-mapped to tammar wallaby chromosomes, and (c tammar wallaby genes orthologous to opossum genes predicted to fill gaps in the tammar wallaby linkage map as well as three X-linked markers from a published study. Based on these 148 loci, eight linkage groups were formed. These linkage groups were assigned (via FISH-mapped markers to all seven autosomes and the X chromosome. The sex-pooled map size is 1402.4 cM, which is estimated to provide 82.6% total coverage of the genome, with an average interval distance of 10.9 cM between adjacent markers. The overall ratio of female/male map length is 0.84, which is comparable to the ratio of 0.78 obtained for the first-generation map. Conclusions Construction of this second-generation genetic linkage map is a significant step towards complete coverage of the tammar wallaby

A second-generation anchored genetic linkage map of the tammar wallaby (Macropus eugenii).

Science.gov (United States)

Wang, Chenwei; Webley, Lee; Wei, Ke-jun; Wakefield, Matthew J; Patel, Hardip R; Deakin, Janine E; Alsop, Amber; Marshall Graves, Jennifer A; Cooper, Desmond W; Nicholas, Frank W; Zenger, Kyall R

2011-08-19

The tammar wallaby, Macropus eugenii, a small kangaroo used for decades for studies of reproduction and metabolism, is the model Australian marsupial for genome sequencing and genetic investigations. The production of a more comprehensive cytogenetically-anchored genetic linkage map will significantly contribute to the deciphering of the tammar wallaby genome. It has great value as a resource to identify novel genes and for comparative studies, and is vital for the ongoing genome sequence assembly and gene ordering in this species. A second-generation anchored tammar wallaby genetic linkage map has been constructed based on a total of 148 loci. The linkage map contains the original 64 loci included in the first-generation map, plus an additional 84 microsatellite loci that were chosen specifically to increase coverage and assist with the anchoring and orientation of linkage groups to chromosomes. These additional loci were derived from (a) sequenced BAC clones that had been previously mapped to tammar wallaby chromosomes by fluorescence in situ hybridization (FISH), (b) End sequence from BACs subsequently FISH-mapped to tammar wallaby chromosomes, and (c) tammar wallaby genes orthologous to opossum genes predicted to fill gaps in the tammar wallaby linkage map as well as three X-linked markers from a published study. Based on these 148 loci, eight linkage groups were formed. These linkage groups were assigned (via FISH-mapped markers) to all seven autosomes and the X chromosome. The sex-pooled map size is 1402.4 cM, which is estimated to provide 82.6% total coverage of the genome, with an average interval distance of 10.9 cM between adjacent markers. The overall ratio of female/male map length is 0.84, which is comparable to the ratio of 0.78 obtained for the first-generation map. Construction of this second-generation genetic linkage map is a significant step towards complete coverage of the tammar wallaby genome and considerably extends that of the first

Wagner vitreoretinal degeneration with genetic linkage refinement on chromosome 5q13-q14.

Science.gov (United States)

Zech, J C; Morlé, L; Vincent, P; Alloisio, N; Bozon, M; Gonnet, C; Milazzo, S; Grange, J D; Trepsat, C; Godet, J; Plauchu, H

1999-05-01

It has been previously described that Wagner disease is linked to chromosome 5q13-q14. This study was carried out to describe the ophthalmological aspects and report the results of genetic linkage analysis in a large pedigree affected by Wagner disease. Fourty members of one same family agreed to be examined. Twenty patients presented vitreoretinal degeneration in both eyes without any extra-ocular abnormalities. In young patients, visual acuity was usually normal after correction of frequent mild myopia. Presenile cataracts progressed by the third decade and required removal for visual rehabilitation. The primary disorder involved an abnormal vitreous. A few avascular vitreous bands were usually the only optical feature in the mostly empty vitreous cavity. A circumferential vitreous condensation formed in contact with the retina on many spots. Less common retinal findings included retinal detachment, abnormal retinal pigmentation, progressive atrophy of the RPE simulating choroideremia and lattice degeneration. Genetic analysis revealed a highly significant linkage (lod score >5.0) between the disease and 10 markers of the chromosome 5q13-q14 region. Two recombination events allowed us to refine the linked interval to 20 cM between the D5S650 and D5S618 markers. Ophthalmological aspects of Wagner's disease appear to progress with age. Regular ophthalmological examination is important for detecting retinal abnormalities. The gene involved in Wagner's disease lies in a 20 cM interval on chromosome 5q13-q14.

Quantitative linkage genome scan for atopy in a large collection of Caucasian families

DEFF Research Database (Denmark)

Webb, BT; van den Oord, E; Akkari, A

2007-01-01

Quantitative phenotypes correlated with a complex disorder offer increased power to detect linkage in comparison to affected-unaffected classifications. Asthma is a complex disorder characterized by periods of bronchial obstruction and increased bronchial hyper reactivity. In childhood and early...... adulthood, asthma is frequently associated also with quantitative measures of atopy. Genome wide quantitative multipoint linkage analysis was conducted for serum IgE levels and percentage of positive skin prick test (SPT(per)) using three large groups of families originally ascertained for asthma....... In this report, 438 and 429 asthma families were informative for linkage using IgE and SPT(per) which represents 690 independent families. Suggestive linkage (LOD >/= 2) was found on chromosomes 1, 3, and 8q with maximum LODs of 2.34 (IgE), 2.03 (SPT(per)), and 2.25 (IgE) near markers D1S1653, D3S2322-D3S1764...

Linear models for joint association and linkage QTL mapping

Directory of Open Access Journals (Sweden)

Fernando Rohan L

2009-09-01

Full Text Available Abstract Background Populational linkage disequilibrium and within-family linkage are commonly used for QTL mapping and marker assisted selection. The combination of both results in more robust and accurate locations of the QTL, but models proposed so far have been either single marker, complex in practice or well fit to a particular family structure. Results We herein present linear model theory to come up with additive effects of the QTL alleles in any member of a general pedigree, conditional to observed markers and pedigree, accounting for possible linkage disequilibrium among QTLs and markers. The model is based on association analysis in the founders; further, the additive effect of the QTLs transmitted to the descendants is a weighted (by the probabilities of transmission average of the substitution effects of founders' haplotypes. The model allows for non-complete linkage disequilibrium QTL-markers in the founders. Two submodels are presented: a simple and easy to implement Haley-Knott type regression for half-sib families, and a general mixed (variance component model for general pedigrees. The model can use information from all markers. The performance of the regression method is compared by simulation with a more complex IBD method by Meuwissen and Goddard. Numerical examples are provided. Conclusion The linear model theory provides a useful framework for QTL mapping with dense marker maps. Results show similar accuracies but a bias of the IBD method towards the center of the region. Computations for the linear regression model are extremely simple, in contrast with IBD methods. Extensions of the model to genomic selection and multi-QTL mapping are straightforward.

Heritability and linkage analysis of personality in bipolar disorder.

Science.gov (United States)

Greenwood, Tiffany A; Badner, Judith A; Byerley, William; Keck, Paul E; McElroy, Susan L; Remick, Ronald A; Dessa Sadovnick, A; Kelsoe, John R

2013-11-01

The many attempts that have been made to identify genes for bipolar disorder (BD) have met with limited success, which may reflect an inadequacy of diagnosis as an informative and biologically relevant phenotype for genetic studies. Here we have explored aspects of personality as quantitative phenotypes for bipolar disorder through the use of the Temperament and Character Inventory (TCI), which assesses personality in seven dimensions. Four temperament dimensions are assessed: novelty seeking (NS), harm avoidance (HA), reward dependence (RD), and persistence (PS). Three character dimensions are also included: self-directedness (SD), cooperativeness (CO), and self-transcendence (ST). We compared personality scores between diagnostic groups and assessed heritability in a sample of 101 families collected for genetic studies of BD. A genome-wide SNP linkage analysis was then performed in the subset of 51 families for which genetic data was available. Significant group differences were observed between BD subjects, their first-degree relatives, and independent controls for all but RD and PS, and all but HA and RD were found to be significantly heritable in this sample. Linkage analysis of the heritable dimensions produced several suggestive linkage peaks for NS (chromosomes 7q21 and 10p15), PS (chromosomes 6q16, 12p13, and 19p13), and SD (chromosomes 4q35, 8q24, and 18q12). The relatively small size of our linkage sample likely limited our ability to reach genome-wide significance in this study. While not genome-wide significant, these results suggest that aspects of personality may prove useful in the identification of genes underlying BD susceptibility. © 2013 Elsevier B.V. All rights reserved.

Bronx Teens Connection's Clinic Linkage Model: Connecting Youth to Quality Sexual and Reproductive Health Care.

Science.gov (United States)

O'Uhuru, Deborah J; Santiago, Vivian; Murray, Lauren E; Travers, Madeline; Bedell, Jane F

2017-03-01

Teen pregnancy and birth rates in the Bronx have been higher than in New York City, representing a longstanding health disparity. The New York City Department of Health and Mental Hygiene implemented a community-wide, multicomponent intervention to reduce unintended teen pregnancy, the Bronx Teens Connection. The Bronx Teens Connection Clinic Linkage Model sought to increase teens' access to and use of sexual and reproductive health care by increasing community partner capacity to link neighborhood clinics to youth-serving organizations, including schools. The Bronx Teens Connection Clinic Linkage Model used needs assessments, delineated the criteria for linkages, clarified roles and responsibilities of partners and staff, established trainings to support the staff engaged in linkage activities, and developed and used process evaluation methods. Early results demonstrated the strength and feasibility of the model over a 4-year period, with 31 linkages developed and maintained, over 11,300 contacts between clinic health educators and teens completed, and increasing adherence to the Centers for Disease Control and Prevention-defined clinical best practices for adolescent reproductive health. For those eight clinics that were able to provide data, there was a 25% increase in the number of teen clients seen over 4 years. There are many factors that relate to an increase in clinic utilization; some of this increase may have been a result of the linkages between schools and clinics. The Bronx Teens Connection Clinic Linkage Model is an explicit framework for clinical and youth-serving organizations seeking to establish formal linkage relationships that may be useful for other municipalities or organizations. Copyright © 2016 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Linkage studies on Gilles de la Tourette syndrome: What is the strategy of choice?

Energy Technology Data Exchange (ETDEWEB)

Heutink, P.; Wetering, J.M. van de; Oostra, B.A. [Erasmus Univ. Rotterdam (Netherlands)] [and others

1995-08-01

For a linkage study it is important to ascertain family material that is sufficiently informative. The statistical power of linkage sample can be determined via computer simulation. For complex traits uncertain parameters such as incomplete penetrance, frequency of phenocopies, gene frequency and variable expression have to be taken into account. One can either include only the most severe phenotype in the analysis or apply multiple linkage tests for a gradually broadened disease phenotype. Gilles de la Tourette syndrome (GTS) is a chronic neurological disorder characterized by multiple, intermittent motor and vocal tics. Segregation analyses suggests that GTS and milder phenotypes are caused by a single dominant gene. We report here the results of an extensive simulation study on a large set of families. We compared the effectiveness of linkage tests with only the GTS phenotype versus multiple tests that included various milder phenotypes and different gene frequencies. The scenario of multiple tests yielded superior power. Our results show that computer simulation can indicate the strategy of choice in linkage studies of multiple, complex phenotypes. 33 refs., 2 figs., 3 tabs.

Internal cycling, not external loading, decides the nutrient limitation in eutrophic lake: A dynamic model with temporal Bayesian hierarchical inference.

Science.gov (United States)

Wu, Zhen; Liu, Yong; Liang, Zhongyao; Wu, Sifeng; Guo, Huaicheng

2017-06-01

Lake eutrophication is associated with excessive anthropogenic nutrients (mainly nitrogen (N) and phosphorus (P)) and unobserved internal nutrient cycling. Despite the advances in understanding the role of external loadings, the contribution of internal nutrient cycling is still an open question. A dynamic mass-balance model was developed to simulate and measure the contributions of internal cycling and external loading. It was based on the temporal Bayesian Hierarchical Framework (BHM), where we explored the seasonal patterns in the dynamics of nutrient cycling processes and the limitation of N and P on phytoplankton growth in hyper-eutrophic Lake Dianchi, China. The dynamic patterns of the five state variables (Chla, TP, ammonia, nitrate and organic N) were simulated based on the model. Five parameters (algae growth rate, sediment exchange rate of N and P, nitrification rate and denitrification rate) were estimated based on BHM. The model provided a good fit to observations. Our model results highlighted the role of internal cycling of N and P in Lake Dianchi. The internal cycling processes contributed more than external loading to the N and P changes in the water column. Further insights into the nutrient limitation analysis indicated that the sediment exchange of P determined the P limitation. Allowing for the contribution of denitrification to N removal, N was the more limiting nutrient in most of the time, however, P was the more important nutrient for eutrophication management. For Lake Dianchi, it would not be possible to recover solely by reducing the external watershed nutrient load; the mechanisms of internal cycling should also be considered as an approach to inhibit the release of sediments and to enhance denitrification. Copyright © 2017 Elsevier Ltd. All rights reserved.

Strengthening industry-research linkage for small scale industrial ...

African Journals Online (AJOL)

Strengthening industry-research linkage for small scale industrial development in Ghana - the relevance of scientific and technological information. ... Journal of Applied Science and Technology. Journal Home · ABOUT · Advanced Search ...

Linkage disequilibrium and association mapping of drought ...

African Journals Online (AJOL)

Drought stress is a major abiotic stress that limits crop production. Molecular association mapping techniques through linkage disequilibrium (LD) can be effectively used to tag genomic regions involved in drought stress tolerance. With the association mapping approach, 90 genotypes of cotton Gossypium hirsutum, from ...

principles, realities and challenges regarding institutional linkages ...

African Journals Online (AJOL)

p2333147

(2) Compromise between proximity to community and effective coordination. If organisational linkage structures are to facilitate effective participation and ownership, it stands to reason that they should be as close to the grassroots community as possible. Unless community members regard such organisational structures as.

Testing for linkage disequilibrium in the New Zealand radiata pine breeding population

Science.gov (United States)

S. Kumar; Craig Echt; P.L. Wilcox; T.E. Richardson

2004-01-01

Linkage analysis is commonly uscd to find marker-trait associations within the full-sib families of forest tree and other species. Study of marker-trait associations at the population level is termed linkage-disequilibrium (LD) mapping. A female-tester design comprising 200 full-sib families generated by crossing 40 pollen parents with five female parents was used to...

A genetic linkage map for the saltwater crocodile (Crocodylus porosus

Directory of Open Access Journals (Sweden)

Lance Stacey L

2009-07-01

Full Text Available Abstract Background Genome elucidation is now in high gear for many organisms, and whilst genetic maps have been developed for a broad array of species, surprisingly, no such maps exist for a crocodilian, or indeed any other non-avian member of the Class Reptilia. Genetic linkage maps are essential tools for the mapping and dissection of complex quantitative trait loci (QTL, and in order to permit systematic genome scans for the identification of genes affecting economically important traits in farmed crocodilians, a comprehensive genetic linage map will be necessary. Results A first-generation genetic linkage map for the saltwater crocodile (Crocodylus porosus was constructed using 203 microsatellite markers amplified across a two-generation pedigree comprising ten full-sib families from a commercial population at Darwin Crocodile Farm, Northern Territory, Australia. Linkage analyses identified fourteen linkage groups comprising a total of 180 loci, with 23 loci remaining unlinked. Markers were ordered within linkage groups employing a heuristic approach using CRIMAP v3.0 software. The estimated female and male recombination map lengths were 1824.1 and 319.0 centimorgans (cM respectively, revealing an uncommonly large disparity in recombination map lengths between sexes (ratio of 5.7:1. Conclusion We have generated the first genetic linkage map for a crocodilian, or indeed any other non-avian reptile. The uncommonly large disparity in recombination map lengths confirms previous preliminary evidence of major differences in sex-specific recombination rates in a species that exhibits temperature-dependent sex determination (TSD. However, at this point the reason for this disparity in saltwater crocodiles remains unclear. This map will be a valuable resource for crocodilian researchers, facilitating the systematic genome scans necessary for identifying genes affecting complex traits of economic importance in the crocodile industry. In addition

Rapid ecological shift following piscivorous fish introduction to increasingly eutrophic and warmer Lake Furnas (Azores Archipelago, Portugal): A paleoecological approach

DEFF Research Database (Denmark)

Buchaca, Teresa; Skov, Tue; Amsinck, Susanne Lildal

2011-01-01

Lake ecosystems are nowadays often subjected to multi-stressors, such as eutrophication, climate change, and fish manipulations, the effects of which can be difficult to disentangle, not least from the usual short-term limnological time-series that are available. However, multi-proxy paleoecologi......Lake ecosystems are nowadays often subjected to multi-stressors, such as eutrophication, climate change, and fish manipulations, the effects of which can be difficult to disentangle, not least from the usual short-term limnological time-series that are available. However, multi......, meteorological forcing, and fish species introduction for recent lake ecosystem development in Lake Furnas on the island of Sa˜o Miguel, the Azores. The lake was stocked with cyprinids in the late nineteenth century and recently also with piscivorous fish, and has been affected by increasing agricultural......, and cryptophytes. The composition of microbial and algal assemblages changed rapidly after Daphnia appearance, and the covariance between fish stocking, nutrient loading, and enhanced temperatures captured most of the variability in algae accumulation, and thus likely in lake primary production as well. Thus, lake...

An improved recommendation algorithm via weakening indirect linkage effect

International Nuclear Information System (INIS)

Chen Guang; Qiu Tian; Shen Xiao-Quan

2015-01-01

We propose an indirect-link-weakened mass diffusion method (IMD), by considering the indirect linkage and the source object heterogeneity effect in the mass diffusion (MD) recommendation method. Experimental results on the MovieLens, Netflix, and RYM datasets show that, the IMD method greatly improves both the recommendation accuracy and diversity, compared with a heterogeneity-weakened MD method (HMD), which only considers the source object heterogeneity. Moreover, the recommendation accuracy of the cold objects is also better elevated in the IMD than the HMD method. It suggests that eliminating the redundancy induced by the indirect linkages could have a prominent effect on the recommendation efficiency in the MD method. (paper)

Can Network Linkage Effects Determine Return? Evidence from Chinese Stock Market.

Science.gov (United States)

Qiao, Haishu; Xia, Yue; Li, Ying

2016-01-01

This study used the dynamic conditional correlations (DCC) method to identify the linkage effects of Chinese stock market, and further detected the influence of network linkage effects on magnitude of security returns across different industries. Applying two physics-derived techniques, the minimum spanning tree and the hierarchical tree, we analyzed the stock interdependence within the network of the China Securities Index (CSI) industry index basket. We observed that that obvious linkage effects existed among stock networks. CII and CCE, CAG and ITH as well as COU, CHA and REI were confirmed as the core nodes in the three different networks respectively. We also investigated the stability of linkage effects by estimating the mean correlations and mean distances, as well as the normalized tree length of these indices. In addition, using the GMM model approach, we found inter-node influence within the stock network had a pronounced effect on stock returns. Our results generally suggested that there appeared to be greater clustering effect among the indexes belonging to related industrial sectors than those of diverse sectors, and network comovement was significantly affected by impactive financial events in the reality. Besides, stocks that were more central within the network of stock market usually had higher returns for compensation because they endured greater exposure to correlation risk.

Salmonid Chromosome Evolution as Revealed by a Novel Method for Comparing RADseq Linkage Maps

Science.gov (United States)

Gosselin, Thierry; Normandeau, Eric; Lamothe, Manuel; Isabel, Nathalie; Audet, Céline; Bernatchez, Louis

2016-01-01

Whole genome duplication (WGD) can provide material for evolutionary innovation. Family Salmonidae is ideal for studying the effects of WGD as the ancestral salmonid underwent WGD relatively recently, ∼65 Ma, then rediploidized and diversified. Extensive synteny between homologous chromosome arms occurs in extant salmonids, but each species has both conserved and unique chromosome arm fusions and fissions. Assembly of large, outbred eukaryotic genomes can be difficult, but structural rearrangements within such taxa can be investigated using linkage maps. RAD sequencing provides unprecedented ability to generate high-density linkage maps for nonmodel species, but can result in low numbers of homologous markers between species due to phylogenetic distance or differences in library preparation. Here, we generate a high-density linkage map (3,826 markers) for the Salvelinus genera (Brook Charr S. fontinalis), and then identify corresponding chromosome arms among the other available salmonid high-density linkage maps, including six species of Oncorhynchus, and one species for each of Salmo, Coregonus, and the nonduplicated sister group for the salmonids, Northern Pike Esox lucius for identifying post-duplicated homeologs. To facilitate this process, we developed MapComp to identify identical and proximate (i.e. nearby) markers between linkage maps using a reference genome of a related species as an intermediate, increasing the number of comparable markers between linkage maps by 5-fold. This enabled a characterization of the most likely history of retained chromosomal rearrangements post-WGD, and several conserved chromosomal inversions. Analyses of RADseq-based linkage maps from other taxa will also benefit from MapComp, available at: https://github.com/enormandeau/mapcomp/ PMID:28173098

A RAD-based linkage map and comparative genomics in the gudgeons (genus Gnathopogon, Cyprinidae

Directory of Open Access Journals (Sweden)

Kakioka Ryo

2013-01-01

Full Text Available Abstract Background The construction of linkage maps is a first step in exploring the genetic basis for adaptive phenotypic divergence in closely related species by quantitative trait locus (QTL analysis. Linkage maps are also useful for comparative genomics in non-model organisms. Advances in genomics technologies make it more feasible than ever to study the genetics of adaptation in natural populations. Restriction-site associated DNA (RAD sequencing in next-generation sequencers facilitates the development of many genetic markers and genotyping. We aimed to construct a linkage map of the gudgeons of the genus Gnathopogon (Cyprinidae for comparative genomics with the zebrafish Danio rerio (a member of the same family as gudgeons and for the future QTL analysis of the genetic architecture underlying adaptive phenotypic evolution of Gnathopogon. Results We constructed the first genetic linkage map of Gnathopogon using a 198 F2 interspecific cross between two closely related species in Japan: river-dwelling Gnathopogon elongatus and lake-dwelling Gnathopogon caerulescens. Based on 1,622 RAD-tag markers, a linkage map spanning 1,390.9 cM with 25 linkage groups and an average marker interval of 0.87 cM was constructed. We also identified a region involving female-specific transmission ratio distortion (TRD. Synteny and collinearity were extensively conserved between Gnathopogon and zebrafish. Conclusions The dense SNP-based linkage map presented here provides a basis for future QTL analysis. It will also be useful for transferring genomic information from a “traditional” model fish species, zebrafish, to screen candidate genes underlying ecologically important traits of the gudgeons.

Biomechanical design of escalading lower limb exoskeleton with novel linkage joints.

Science.gov (United States)

Zhang, Guoan; Liu, Gangfeng; Ma, Sun; Wang, Tianshuo; Zhao, Jie; Zhu, Yanhe

2017-07-20

In this paper, an obstacle-surmounting-enabled lower limb exoskeleton with novel linkage joints that perfectly mimicked human motions was proposed. Currently, most lower exoskeletons that use linear actuators have a direct connection between the wearer and the controlled part. Compared to the existing joints, the novel linkage joint not only fitted better into compact chasis, but also provided greater torque when the joint was at a large bend angle. As a result, it extended the angle range of joint peak torque output. With any given power, torque was prioritized over rotational speed, because instead of rotational speed, sufficiency of torque is the premise for most joint actions. With insufficient torque, the exoskeleton will be a burden instead of enhancement to its wearer. With optimized distribution of torque among the joints, the novel linkage method may contribute to easier exoskeleton movements.

Genomewide Linkage Scan for Diabetic Renal Failure and Albuminuria: The FIND Study

Science.gov (United States)

Igo, Robert P.; Iyengar, Sudha K.; Nicholas, Susanne B.; Goddard, Katrina A.B.; Langefeld, Carl D.; Hanson, Robert L.; Duggirala, Ravindranath; Divers, Jasmin; Abboud, Hanna; Adler, Sharon G.; Arar, Nedal H.; Horvath, Amanda; Elston, Robert C.; Bowden, Donald W.; Guo, Xiuqing; Ipp, Eli; Kao, W.H. Linda; Kimmel, Paul L.; Knowler, William C.; Meoni, Lucy A.; Molineros, Julio; Nelson, Robert G.; Pahl, Madeline V.; Parekh, Rulan S.; Rasooly, Rebekah S.; Schelling, Jeffrey R.; Shah, Vallabh O.; Smith, Michael W.; Winkler, Cheryl A.; Zager, Philip G.; Sedor, John R.; Freedman, Barry I.

2011-01-01

Background Diabetic nephropathy (DN) is a leading cause of mortality and morbidity in patients with type 1 and type 2 diabetes. The multicenter FIND consortium aims to identify genes for DN and its associated quantitative traits, e.g. the urine albumin:creatinine ratio (ACR). Herein, the results of whole-genome linkage analysis and a sparse association scan for ACR and a dichotomous DN phenotype are reported in diabetic individuals. Methods A genomewide scan comprising more than 5,500 autosomal single nucleotide polymorphism markers (average spacing of 0.6 cM) was performed on 1,235 nuclear and extended pedigrees (3,972 diabetic participants) ascertained for DN from African-American (AA), American-Indian (AI), European-American (EA) and Mexican-American (MA) populations. Results Strong evidence for linkage to DN was detected on chromosome 6p (p = 8.0 × 10−5, LOD = 3.09) in EA families as well as suggestive evidence for linkage to chromosome 7p in AI families. Regions on chromosomes 3p in AA, 7q in EA, 16q in AA and 22q in MA displayed suggestive evidence of linkage for urine ACR. The linkage peak on chromosome 22q overlaps the MYH9/APOL1 gene region, previously implicated in AA diabetic and nondiabetic nephropathies. Conclusion These results strengthen the evidence for previously identified genomic regions and implicate several novel loci potentially involved in the pathogenesis of DN. PMID:21454968

Could an airburst above Canada at the Younger Dryas onset trigger lake eutrophication and acidification in central Europe?

Czech Academy of Sciences Publication Activity Database

Stuchlík, Evžen; Kletetschka, G.; Hořická, Zuzana; Hrubá, J.; Nábělek, L.; Svitavská-Svobodová, Helena; Bobek, Přemysl; Kadlec, Jaroslav; Takac, M.; Vondrák, D.

2017-01-01

Roč. 52, S1 (2017), A335-A335, č. článku 6247. ISSN 1086-9379. [Annual Meeting of the Meteoritical Society /80./. 23.07.2017-28.07.2017, Santa Fe] R&D Projects: GA ČR(CZ) GA17-05935S Institutional support: RVO:60077344 ; RVO:67985939 ; RVO:67985530 Keywords : airburst * lake * eutrophication * acidification * paleolimnology Subject RIV: DA - Hydrology ; Limnology; EH - Ecology, Behaviour (BU-J)

Non-participation in preventive child health examinations at the general practitioner in Denmark

DEFF Research Database (Denmark)

Søndergaard, Grethe; Biering-Sørensen, Sofie; Michelsen, Susan Ishøy

2008-01-01

Objective. To examine demographic and socioeconomic characteristics of parents and children in families not participating in preventive child health examinations at the general practitioner in a society with free and easy access to healthcare. Design. Population-covering register linkage study...... free and easy access to the GP, the utilization of preventive child health examinations is lower among the more deprived part of the population....

Interactive network configuration maintains bacterioplankton community structure under elevated CO2 in a eutrophic coastal mesocosm experiment

Science.gov (United States)

Lin, Xin; Huang, Ruiping; Li, Yan; Li, Futian; Wu, Yaping; Hutchins, David A.; Dai, Minhan; Gao, Kunshan

2018-01-01

There is increasing concern about the effects of ocean acidification on marine biogeochemical and ecological processes and the organisms that drive them, including marine bacteria. Here, we examine the effects of elevated CO2 on the bacterioplankton community during a mesocosm experiment using an artificial phytoplankton community in subtropical, eutrophic coastal waters of Xiamen, southern China. Through sequencing the bacterial 16S rRNA gene V3-V4 region, we found that the bacterioplankton community in this high-nutrient coastal environment was relatively resilient to changes in seawater carbonate chemistry. Based on comparative ecological network analysis, we found that elevated CO2 hardly altered the network structure of high-abundance bacterioplankton taxa but appeared to reassemble the community network of low abundance taxa. This led to relatively high resilience of the whole bacterioplankton community to the elevated CO2 level and associated chemical changes. We also observed that the Flavobacteria group, which plays an important role in the microbial carbon pump, showed higher relative abundance under the elevated CO2 condition during the early stage of the phytoplankton bloom in the mesocosms. Our results provide new insights into how elevated CO2 may influence bacterioplankton community structure.

Linkage of the National Health Interview Survey to air quality data

OpenAIRE

Parker, JD; Kravets, N; Woodruff, TJ

2012-01-01

Objective This report describes the linkage between the National Health Interview Survey (NHIS) and air monitoring data from the U.S. Environmental Protection Agency (EPA). There have been few linkages of these data sources, partly because of restrictions on releasing geographic detail from NHIS on public-use files in order to protect participant confidentiality. Methods Pollution exposures for NHIS respondents were calculated by averaging the annual average exposure estimates from EPA air mo...

Linkage disequilibrium and demographic history of the isolated population of the Faroe Islands

DEFF Research Database (Denmark)

Jorgensen, Tove H; Degn, Birte; Wang, August G

2002-01-01

The isolated population of the Faroe Islands has a history of recent expansion after being limited to a small size for centuries. Such an isolated population may be ideal for linkage disequilibrium mapping of disease genes if linkage disequilibrium (LD) extends over large regions. Analyses of 18 ...

Metal accumulation and oxidative stress responses in Ulva spp. in the presence of nocturnal pulses of metals from sediment: A field transplantation experiment under eutrophic conditions

KAUST Repository

Pereira, Patrícia M R

2014-03-01

In aquatic systems under eutrophic conditions, remobilization of metals from sediment to the overlying water may occur. Consequently, adaptive responses of local organisms could result from the accumulation of metals intermittently released from the sediment. In summer 2007, a field transplantation experiment was performed in the Óbidos lagoon (Portugal) with Ulva spp. comprising three short-term exposures (between 15:30-23:30; 23:30-07:30; 07:30-15:30) during a 24-h period. In each period, Ulva spp. was collected at a reference site located in the lower lagoon (LL) and transplanted to a eutrophic site located at the Barrosa branch (BB), characterized by moderate metal contamination. For comparison purposes, macroalgae samples were simultaneously exposed at LL under the same conditions. Both sites were surveyed in short-time scales (2-4 h) for the analysis of the variability of physical-chemical parameters in the water and metal levels in suspended particulate matter. The ratios to Al of particulate Mn, Fe, Cu and Pb increased during the period of lower water oxygenation at the eutrophic site, reaching 751 × 10-4, 0.67, 12 × 10-4, 9.9 × 10-4, respectively, confirming the release of metals from the sediment to water during the night. At the reference site, dissolved oxygen oscillated around 100%, Mn/Al ratios were considerably lower (81 × 10-4-301 × 10-4) compared to BB (234 × 10-4-790 × 10-4), and no increases of metal/Al ratios were found during the night. In general, algae uptake of Mn, Cu, Fe, Pb and Cd was significantly higher at the eutrophic site compared to the reference site. The results confirmed the potential of Ulva spp. as bioindicator of metal contamination and its capability to respond within short periods. An induction of SOD, an inhibition of CAT and the increase of LPO were recorded in Ulva spp. exposed at BB (between 23:30 and 7:30) probably as a response to the higher incorporation of Mn, Fe and Pb in combination with the lack of

Optimizing Opt-Out Consent for Record Linkage

Directory of Open Access Journals (Sweden)

Das Marcel

2014-09-01

Full Text Available This article reports on a study testing the effects of different ways of administering an opt-out consent for record linkage in a probability-based Internet panel. First, we conducted cognitive interviews to explore reactions to a draft version of the opt-out consent text. Second, we conducted a two-factor experiment to test the effects of content manipulations and mode. The results indicate that the way in which respondents were informed did not have much effect on opting out. Results from a follow-up survey on attitudes regarding privacy, confidentiality, and trust, along with knowledge questions about the process of linking, showed no evidence that presenting the opt-out consent statement makes respondents more concerned about privacy. Knowledge about the aspects of record linkage is generally not high. When looking at long-term effects of sending an opt-out consent statement, we found no evidence that this leads to higher attrition or lower participation rates.

Vertical distribution and community composition of anammox bacteria in sediments of a eutrophic shallow lake.

Science.gov (United States)

Qin, H; Han, C; Jin, Z; Wu, L; Deng, H; Zhu, G; Zhong, W

2018-07-01

The aim of this study was to explore the vertical distribution traits of anaerobic ammonium-oxidizing (anammox) bacterial relative abundance and community composition along the oxic/anoxic sediment profiles in a shallow lake. The Illumina Miseq-based sequencing and quantitative polymerase chain reactions were utilized to analyse relative abundance of anammox hydrazine synthase (hzsB) gene in comparison with bacterial 16S rRNA genes, anammox bacterial relative abundance (the number of anammox sequences divided by total number of sequences), community composition and diversity in sediments. The relative abundance of hzsB gene at the low-nitrogen (LN) site in the lake sediments showed that the vertical distribution of anammox bacteria increased to a peak, then decreased with increasing depth. Moreover, the relative abundance of hzsB gene at the high-nitrogen site was significantly lower than that at the LN site. Additionally, the community composition results showed that Candidatus Brocadia sp. was the dominant genus. In addition, the anammox bacterial diversity was also site specific. Redundancy analysis showed that the total N and the NH 4 + -N content might be the most important factors affecting anammox bacterial community composition in the studied sites. The results revealed the specific vertical variance of anammox bacterial distribution and community composition in oxic/anoxic sediments of a eutrophic shallow lake. This is the first study to demonstrate that anammox bacteria displayed the particular distribution in freshwater sediments, which implied a strong response to the anthropogenic eutrophication. © 2018 The Society for Applied Microbiology.

Initial Reactivity of Linkages and Monomer Rings in Lignin Pyrolysis Revealed by ReaxFF Molecular Dynamics.

Science.gov (United States)

Zhang, Tingting; Li, Xiaoxia; Guo, Li

2017-10-24

The initial conversion pathways of linkages and their linked monomer units in lignin pyrolysis were investigated comprehensively by ReaxFF MD simulations facilitated by the unique VARxMD for reaction analysis. The simulated molecular model contains 15 920 atoms and was constructed on the basis of Adler's softwood lignin model. The simulations uncover the initial conversion ratio of various linkages and their linked aryl monomers. For linkages and their linked monomer aryl rings of α-O-4, β-O-4 and α-O-4 & β-5, the C α /C β ether bond cracking dominates the initial pathway accounting for at least up to 80% of their consumption. For the linkage of β-β & γ-O-α, both the C α -O ether bond cracking and its linked monomer aryl ring opening are equally important. Ring-opening reactions dominate the initial consumption of other 4-O-5, 5-5, β-1, β-2, and β-5 linkages and their linked monomers. The ether bond cracking of C α -O and C β -O occurs at low temperature, and the aryl ring-opening reactions take place at relatively high temperature. The important intermediates leading to the stable aryl ring opening are the phenoxy radicals, the bridged five-membered and three-membered rings and the bridged six-membered and three-membered rings. In addition, the reactivity of a linkage and its monomer aryl ring may be affected by other linkages. The ether bond cracking of α-O-4 and β-O-4 linkages can activate its neighboring linkage or monomer ring through the formed phenoxy radicals as intermediates. The important intermediates revealed in this article should be of help in deepening the understanding of the controlling mechanism for producing aromatic chemicals from lignin pyrolysis.

Construction of an SSR and RAD-Marker Based Molecular Linkage Map of Vigna vexillata (L.) A. Rich.

Science.gov (United States)

Marubodee, Rusama; Ogiso-Tanaka, Eri; Isemura, Takehisa; Chankaew, Sompong; Kaga, Akito; Naito, Ken; Ehara, Hiroshi; Tomooka, Norihiko

2015-01-01

Vigna vexillata (L.) A. Rich. (tuber cowpea) is an underutilized crop for consuming its tuber and mature seeds. Wild form of V. vexillata is a pan-tropical perennial herbaceous plant which has been used by local people as a food. Wild V. vexillata has also been considered as useful gene(s) source for V. unguiculata (cowpea), since it was reported to have various resistance gene(s) for insects and diseases of cowpea. To exploit the potential of V. vexillata, an SSR-based linkage map of V. vexillata was developed. A total of 874 SSR markers successfully amplified single DNA fragment in V. vexillata among 1,336 SSR markers developed from Vigna angularis (azuki bean), V. unguiculata and Phaseolus vulgaris (common bean). An F2 population of 300 plants derived from a cross between salt resistant (V1) and susceptible (V5) accessions was used for mapping. A genetic linkage map was constructed using 82 polymorphic SSR markers loci, which could be assigned to 11 linkage groups spanning 511.5 cM in length with a mean distance of 7.2 cM between adjacent markers. To develop higher density molecular linkage map and to confirm SSR markers position in a linkage map, RAD markers were developed and a combined SSR and RAD markers linkage map of V. vexillata was constructed. A total of 559 (84 SSR and 475 RAD) markers loci could be assigned to 11 linkage groups spanning 973.9 cM in length with a mean distance of 1.8 cM between adjacent markers. Linkage and genetic position of all SSR markers in an SSR linkage map were confirmed. When an SSR genetic linkage map of V. vexillata was compared with those of V. radiata and V. unguiculata, it was suggested that the structure of V. vexillata chromosome was considerably differentiated. This map is the first SSR and RAD marker-based V. vexillata linkage map which can be used for the mapping of useful traits.

Effects of dissolved organic matter from a eutrophic lake on the freely dissolved concentrations of emerging organic contaminants.

Science.gov (United States)

Xiao, Yi-Hua; Huang, Qing-Hui; Vähätalo, Anssi V; Li, Fei-Peng; Chen, Ling

2014-08-01

The authors studied the effects of dissolved organic matter (DOM) on the bioavailability of bisphenol A (BPA) and chloramphenicol by measuring the freely dissolved concentrations of the contaminants in solutions containing DOM that had been isolated from a mesocosm in a eutrophic lake. The abundance and aromaticity of the chromophoric DOM increased over the 25-d mesocosm experiment. The BPA freely dissolved concentration was 72.3% lower and the chloramphenicol freely dissolved concentration was 56.2% lower using DOM collected on day 25 than using DOM collected on day 1 of the mesocosm experiment. The freely dissolved concentrations negatively correlated with the ultraviolent absorption coefficient at 254 nm and positively correlated with the spectral slope of chromophoric DOM, suggesting that the bioavailability of these emerging organic contaminants depends on the characteristics of the DOM present. The DOM-water partition coefficients (log KOC ) for the emerging organic contaminants positively correlated with the aromaticity of the DOM, measured as humic acid-like fluorescent components C1 (excitation/emission=250[313]/412 nm) and C2 (excitation/emission=268[379]/456 nm). The authors conclude that the bioavailability of emerging organic contaminants in eutrophic lakes can be affected by changes in the DOM. © 2014 SETAC.

Effects of eutrophication, seasonality and macrofouling on the diversity of bacterial biofilms in equatorial coral reefs.

Directory of Open Access Journals (Sweden)

Yvonne Sawall

Full Text Available Biofilms play an important role as a settlement cue for invertebrate larvae and significantly contribute to the nutrient turnover in aquatic ecosystems. Nevertheless, little is known about how biofilm community structure generally responds to environmental changes. This study aimed to identify patterns of bacterial dynamics in coral reef biofilms in response to associated macrofouling community structure, microhabitat (exposed vs. sheltered, seasonality, and eutrophication. Settlement tiles were deployed at four reefs along a cross-shelf eutrophication gradient and were exchanged every 4 months over 20 months. The fouling community composition on the tiles was recorded and the bacterial community structure was assessed with the community fingerprinting technique Automated Ribosomal Intergenic Spacer Analysis (ARISA. Bacterial operational taxonomic unit (OTU number was higher on exposed tiles, where the fouling community was homogenous and algae-dominated, than in sheltered habitats, which were occupied by a variety of filter feeders. Furthermore, OTU number was also highest in eutrophied near-shore reefs, while seasonal variations in community structure were most pronounced in the oligotrophic mid-shelf reef. In contrast, the macrofouling community structure did not change significantly with seasons. Changes in bacterial community patterns were mostly affected by microhabitat, seasonal and anthropogenically derived changes in nutrient availability, and to a lesser extent by changes in the macrofouling community structure. Path analysis revealed a complex interplay of various environmental and biological factors explaining the spatial and temporal variations in bacterial biofilm communities under natural conditions.

Molecular analysis and test of linkage between the FMR-I gene and infantile autism in multiplex families

Energy Technology Data Exchange (ETDEWEB)

Hallmayer, J.; Pintado, E.; Lotspeich, L.; Spiker, D.; Kraemer, H.C.; Lee Wong, D.; Lin, A.; Herbert, J.; Cavalli-Sforza, L.L.; Ciaranello, R.D. [Stanford Univ., CA (United States)] [and others

1994-11-01

Approximately 2%-5% of autistic children show cytogenetic evidence of the fragile X syndrome. This report tests whether infantile autism in multiplex autism families arises from an unusual manifestion of the fragile X syndrome. This could arise either by expansion of the (CGG)n trinucleotide repeat in FMR-1 or from a mutation elsewhere in the gene. We studied 35 families that met stringent criteria for multiplex autism. Amplification of the trinucleotide repeat and analysis of methylation status were performed in 79 autistic children and in 31 of their unaffected siblings by Southern blot analysis. No examples of amplified repeats were seen in the autistic or control children or in their parents or grandparents. We next examined the hypothesis that there was a mutation elsewhere in the FMR-1 gene, by linkage analysis in 32 of these families. We tested four different dominant models and a recessive model. Linkage to FMR-1 could be excluded (lod score between -24 and -62) in all models by using probes DXS548, FRAXAC1, and FRAXAC2 and the CGG repeat itself. Tests for heterogeneity in this sample were negative, and the occurrence of positive lod scores in this data set could be attributed to chance. Analysis of the data by the affected-sib method also did not show evidence for linkage of any marker to autism. These results enable us to reject the hypothesis that multiplex autism arises from expansion of the (CGG)n trinucleotide repeat in FMR-1. Further, because the overall lod scores for all probes in all models tested were highly negative, linkage to FMR-1 can also be ruled out in multiplex autistic families. 35 refs., 2 figs., 5 tabs.

Revealing the fate of the phenylcoumaran linkage during lignin oxidation reactions.

Science.gov (United States)

Lahive, Ciaran W; Lancefield, Christopher S; Codina, Anna; Kamer, Paul C J; Westwood, Nicholas J

2018-03-14

The fate of most lignin linkages, other than the β-O-4, under selective oxidation conditions is largely unknown. In this work we use advanced β-5 lignin model compounds to identify the fate of phenylcoumaran units in a softwood lignin during oxidation with DDQ. By using model compounds combined with detailed characterisation of the oxidised lignin polymer using HSQC and HMBC NMR we show that phenylcoumarones are a major product, and therefore constitute a novel non-native β-5 linkage in oxidised lignins. Additionally, the reactivity of these units in lignin led us to further investigate their connectivity in lignin, showing that they are found as both phenolic and etherified units. The findings and approach developed here will help improve the efficiency of selective oxidative lignin depolymerisation processes, particularly those aimed at the upgrading of softwood lignin in which phenylcoumarans are a major linkage.

Meta-analysis of genome-wide linkage studies in BMI and obesity.

Science.gov (United States)

Saunders, Catherine L; Chiodini, Benedetta D; Sham, Pak; Lewis, Cathryn M; Abkevich, Victor; Adeyemo, Adebowale A; de Andrade, Mariza; Arya, Rector; Berenson, Gerald S; Blangero, John; Boehnke, Michael; Borecki, Ingrid B; Chagnon, Yvon C; Chen, Wei; Comuzzie, Anthony G; Deng, Hong-Wen; Duggirala, Ravindranath; Feitosa, Mary F; Froguel, Philippe; Hanson, Robert L; Hebebrand, Johannes; Huezo-Dias, Patricia; Kissebah, Ahmed H; Li, Weidong; Luke, Amy; Martin, Lisa J; Nash, Matthew; Ohman, Miina; Palmer, Lyle J; Peltonen, Leena; Perola, Markus; Price, R Arlen; Redline, Susan; Srinivasan, Sathanur R; Stern, Michael P; Stone, Steven; Stringham, Heather; Turner, Stephen; Wijmenga, Cisca; Collier, David A

2007-09-01

The objective was to provide an overall assessment of genetic linkage data of BMI and BMI-defined obesity using a nonparametric genome scan meta-analysis. We identified 37 published studies containing data on over 31,000 individuals from more than >10,000 families and obtained genome-wide logarithm of the odds (LOD) scores, non-parametric linkage (NPL) scores, or maximum likelihood scores (MLS). BMI was analyzed in a pooled set of all studies, as a subgroup of 10 studies that used BMI-defined obesity, and for subgroups ascertained through type 2 diabetes, hypertension, or subjects of European ancestry. Bins at chromosome 13q13.2- q33.1, 12q23-q24.3 achieved suggestive evidence of linkage to BMI in the pooled analysis and samples ascertained for hypertension. Nominal evidence of linkage to these regions and suggestive evidence for 11q13.3-22.3 were also observed for BMI-defined obesity. The FTO obesity gene locus at 16q12.2 also showed nominal evidence for linkage. However, overall distribution of summed rank p values <0.05 is not different from that expected by chance. The strongest evidence was obtained in the families ascertained for hypertension at 9q31.1-qter and 12p11.21-q23 (p < 0.01). Despite having substantial statistical power, we did not unequivocally implicate specific loci for BMI or obesity. This may be because genes influencing adiposity are of very small effect, with substantial genetic heterogeneity and variable dependence on environmental factors. However, the observation that the FTO gene maps to one of the highest ranking bins for obesity is interesting and, while not a validation of this approach, indicates that other potential loci identified in this study should be investigated further.

Irish study of high-density Schizophrenia families: Field methods and power to detect linkage

Energy Technology Data Exchange (ETDEWEB)

Kendler, K.S.; Straub, R.E.; MacLean, C.J. [Virginia Commonwealth Univ., Richmond, VA (United States)] [and others

1996-04-09

Large samples of multiplex pedigrees will probably be needed to detect susceptibility loci for schizophrenia by linkage analysis. Standardized ascertainment of such pedigrees from culturally and ethnically homogeneous populations may improve the probability of detection and replication of linkage. The Irish Study of High-Density Schizophrenia Families (ISHDSF) was formed from standardized ascertainment of multiplex schizophrenia families in 39 psychiatric facilities covering over 90% of the population in Ireland and Northern Ireland. We here describe a phenotypic sample and a subset thereof, the linkage sample. Individuals were included in the phenotypic sample if adequate diagnostic information, based on personal interview and/or hospital record, was available. Only individuals with available DNA were included in the linkage sample. Inclusion of a pedigree into the phenotypic sample required at least two first, second, or third degree relatives with non-affective psychosis (NAP), one of whom had schizophrenia (S) or poor-outcome schizoaffective disorder (PO-SAD). Entry into the linkage sample required DNA samples on at least two individuals with NAP, of whom at least one had S or PO-SAD. Affection was defined by narrow, intermediate, and broad criteria. 75 refs., 6 tabs.

Drivers, mechanisms and long-term variability of seasonal hypoxia on the Black Sea northwestern shelf – is there any recovery after eutrophication?

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A. Capet

2013-06-01

Full Text Available The Black Sea northwestern shelf (NWS is a shallow eutrophic area in which the seasonal stratification of the water column isolates the bottom waters from the atmosphere. This prevents ventilation from counterbalancing the large consumption of oxygen due to respiration in the bottom waters and in the sediments, and sets the stage for the development of seasonal hypoxia. A three-dimensional (3-D coupled physical–biogeochemical model is used to investigate the dynamics of bottom hypoxia in the Black Sea NWS, first at seasonal and then at interannual scales (1981–2009, and to differentiate its driving factors (climatic versus eutrophication. Model skills are evaluated by a quantitative comparison of the model results to 14 123 in situ oxygen measurements available in the NOAA World Ocean and the Black Sea Commission databases, using different error metrics. This validation exercise shows that the model is able to represent the seasonal and interannual variability of the oxygen concentration and of the occurrence of hypoxia, as well as the spatial distribution of oxygen-depleted waters. During the period 1981–2009, each year exhibits seasonal bottom hypoxia at the end of summer. This phenomenon essentially covers the northern part of the NWS – which receives large inputs of nutrients from the Danube, Dniester and Dnieper rivers – and extends, during the years of severe hypoxia, towards the Romanian bay of Constanta. An index H which merges the aspects of the spatial and temporal extension of the hypoxic event is proposed to quantify, for each year, the intensity of hypoxia as an environmental stressor. In order to explain the interannual variability of H and to disentangle its drivers, we analyze the long time series of model results by means of a stepwise multiple linear regression. This statistical model gives a general relationship that links the intensity of hypoxia to eutrophication and climate-related variables. A total of 82% of the

Mapping Aquatic Vegetation in a Large, Shallow Eutrophic Lake: A Frequency-Based Approach Using Multiple Years of MODIS Data

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Xiaohan Liu

2015-08-01

Full Text Available Aquatic vegetation serves many important ecological and socioeconomic functions in lake ecosystems. The presence of floating algae poses difficulties for accurately estimating the distribution of aquatic vegetation in eutrophic lakes. We present an approach to map the distribution of aquatic vegetation in Lake Taihu (a large, shallow eutrophic lake in China and reduce the influence of floating algae on aquatic vegetation mapping. Our approach involved a frequency analysis over a 2003–2013 time series of the floating algal index (FAI based on moderate-resolution imaging spectroradiometer (MODIS data. Three phenological periods were defined based on the vegetation presence frequency (VPF and the growth of algae and aquatic vegetation: December and January composed the period of wintering aquatic vegetation; February and March composed the period of prolonged coexistence of algal blooms and wintering aquatic vegetation; and June to October was the peak period of the coexistence of algal blooms and aquatic vegetation. By comparing and analyzing the satellite-derived aquatic vegetation distribution and 244 in situ measurements made in 2013, we established a FAI threshold of −0.025 and VPF thresholds of 0.55, 0.45 and 0.85 for the three phenological periods. We validated the accuracy of our approach by comparing the results between the satellite-derived maps and the in situ results obtained from 2008–2012. The overall classification accuracy was 87%, 81%, 77%, 88% and 73% in the five years from 2008–2012, respectively. We then applied the approach to the MODIS images from 2003–2013 and obtained the total area of the aquatic vegetation, which varied from 265.94 km2 in 2007 to 503.38 km2 in 2008, with an average area of 359.62 ± 69.20 km2 over the 11 years. Our findings suggest that (1 the proposed approach can be used to map the distribution of aquatic vegetation in eutrophic algae-rich waters and (2 dramatic changes occurred in the

Use of record linkage to examine alcohol use in pregnancy.

Science.gov (United States)

Burns, Lucy; Mattick, Richard P; Cooke, Margaret

2006-04-01

To date, no population-level data have been published examining the obstetric and neonatal outcomes for women with an alcohol-related hospital admission during pregnancy compared with the general obstetric population. This information is critical to planning and implementing appropriate services. Antenatal and delivery admissions to New South Wales (NSW) hospitals from the NSW Inpatient Statistics Collection were linked to birth information from the NSW Midwives Data Collection over a 5-year period (1998-2002). Birth admissions were flagged as positive for maternal alcohol use where a birth admission or any pregnancy admission for that birth involved an alcohol-related International Statistical Classification of Diseases and Related Health Problems, 10th Revision, Australian Modification (ICD-10-AM) code. Key demographic, obstetric, and neonatal variables were compared for births to mothers in the alcohol group with births where no alcohol-related ICD10-AM was recorded. A total of 416,834 birth records were analyzed over a 5-year period (1998-2002). In this time, 342 of these were coded as positive for at least 1 alcohol-related ICD-10-AM diagnosis. Mothers in the alcohol group had a higher number of previous pregnancies, smoked more heavily, were not privately insured, and were more often indigenous. They also presented later on in their pregnancy to antenatal services and were more likely to arrive at hospital unbooked for delivery. Deliveries involved less epidural and local and more general anesthesia. Cesarean sections were more common to women in the alcohol group and were performed more often for intrauterine growth retardation. Neonates born to women in the alcohol group were smaller for gestational age, had lower Apgar scores at 5 minutes, and were admitted to special care nursery more often. This study shows that linked population-level administrative data provide a powerful new source of information for examining the maternal and neonatal outcomes

Development of constructed wetland using hydroponic biofilter method for purification of hyper-eutrophic lake water; Fueiyoka kosui no joka no tameno suiko seibutsu rokaho wo mochiita jinko shicchi no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Aizaki, M. [Shimane Univ., Matsue (Japan)] Nakasato, H. [Top Ecology Co. Ltd., Tokyo (Japan)

1997-09-10

Applying the hydroponic biofilter method as a direct purification method for a hyper-eutrophic lake water, an experiment was carried out at the Tsuchiura Port on Lake Kasumigaura to obtain data for constructing a hydrophilic artificial wetland. Purification of hyper-eutrophic lake water containing a large amount of water blooms in summer was attempted applying the hydroponic biofilter method for which hydrophyte is used. As a result, it was clarified, by applying the hydroponic biofilter method, that capturing effect of suspended substances can be achieved in the rooting zone, captured suspended substances are decomposed at high rate, and the revolved nutrient salt can be absorbed and assimilated by the use of plants having high growth rates. Ipomoea aquatica had the highest removal activity, followed by nasturtium officinal, menthe spicata, and oenanthe javanica. As a result, it became clear that a constructed wetland made with the hydroponic biofilter method can be applied as a direct purifying method for hyper-eutrophic lake water by selecting appropriate plants in accordance with season. 18 refs., 1 fig., 4 tabs.

Metal accumulation and oxidative stress responses in Ulva spp. in the presence of nocturnal pulses of metals from sediment: A field transplantation experiment under eutrophic conditions

KAUST Repository

Pereira, Patrí cia M R; De Pablo, Hilda; Guilherme, S. Isabel Antunes Gomes; Carvalho, Susana; Santos, Maria Ana S; Vale, Carlos; Pacheco, Má rio Guilherme Garcê s

2014-01-01

emphasize the importance of assessing, in eutrophic systems, the relationship between the variability of chemical conditions and its repercussions on autochthonous organisms over day-night cycles. © 2013 Elsevier Ltd.

Genotyping by Sequencing in Almond: SNP Discovery, Linkage Mapping, and Marker Design

Directory of Open Access Journals (Sweden)

Shashi N. Goonetilleke

2018-01-01

Full Text Available In crop plant genetics, linkage maps provide the basis for the mapping of loci that affect important traits and for the selection of markers to be applied in crop improvement. In outcrossing species such as almond (Prunus dulcis Mill. D. A. Webb, application of a double pseudotestcross mapping approach to the F1 progeny of a biparental cross leads to the construction of a linkage map for each parent. Here, we report on the application of genotyping by sequencing to discover and map single nucleotide polymorphisms in the almond cultivars “Nonpareil” and “Lauranne.” Allele-specific marker assays were developed for 309 tag pairs. Application of these assays to 231 Nonpareil × Lauranne F1 progeny provided robust linkage maps for each parent. Analysis of phenotypic data for shell hardness demonstrated the utility of these maps for quantitative trait locus mapping. Comparison of these maps to the peach genome assembly confirmed high synteny and collinearity between the peach and almond genomes. The marker assays were applied to progeny from several other Nonpareil crosses, providing the basis for a composite linkage map of Nonpareil. Applications of the assays to a panel of almond clones and a panel of rootstocks used for almond production demonstrated the broad applicability of the markers and provide subsets of markers that could be used to discriminate among accessions. The sequence-based linkage maps and single nucleotide polymorphism assays presented here could be useful resources for the genetic analysis and genetic improvement of almond.

Combined linkage and association mapping of flowering time in Sunflower (Helianthus annuus L.).

Science.gov (United States)

Cadic, Elena; Coque, Marie; Vear, Felicity; Grezes-Besset, Bruno; Pauquet, Jerôme; Piquemal, Joël; Lippi, Yannick; Blanchard, Philippe; Romestant, Michel; Pouilly, Nicolas; Rengel, David; Gouzy, Jerôme; Langlade, Nicolas; Mangin, Brigitte; Vincourt, Patrick

2013-05-01

Association mapping and linkage mapping were used to identify quantitative trait loci (QTL) and/or causative mutations involved in the control of flowering time in cultivated sunflower Helianthus annuus. A panel of 384 inbred lines was phenotyped through testcrosses with two tester inbred lines across 15 location × year combinations. A recombinant inbred line (RIL) population comprising 273 lines was phenotyped both per se and through testcrosses with one or two testers in 16 location × year combinations. In the association mapping approach, kinship estimation using 5,923 single nucleotide polymorphisms was found to be the best covariate to correct for effects of panel structure. Linkage disequilibrium decay ranged from 0.08 to 0.26 cM for a threshold of 0.20, after correcting for structure effects, depending on the linkage group (LG) and the ancestry of inbred lines. A possible hitchhiking effect is hypothesized for LG10 and LG08. A total of 11 regions across 10 LGs were found to be associated with flowering time, and QTLs were mapped on 11 LGs in the RIL population. Whereas eight regions were demonstrated to be common between the two approaches, the linkage disequilibrium approach did not detect a documented QTL that was confirmed using the linkage mapping approach.

Kempe's Linkages and the Universality Theorem

Indian Academy of Sciences (India)

sriranga

that between BO and OA (i.e., \\BOA). Let these two angles be denoted by µ. Thus, if link OA makes an angle. µ with link OB, OE makes the same angle on the other side of OB. Kempe therefore referred to this linkage as the (angle) reversor. This is true irrespective of how OA and OB are placed relative to each other. Also ...

A study of inter linkage effects on Candu feeder piping

International Nuclear Information System (INIS)

Li, M.; Aggarwal, M.L.; Meysner, A.

2005-01-01

A CANDU (Canadian Deuterium Uranium) reactor core consists of a large number of fuel channels where heat is generated. Two feeder pipes are connected to each fuel channel to transport D 2 O coolant into and out of the reactor core. The feeder piping is designed to the requirements of Class 1 piping of Section III NB of the ASME Boiler and Pressure Vessel and CSA Codes. Feeder piping stress analysis is being performed to demonstrate the code compliance check and the fitness for service of feeders. In the past, stress analyses were conducted for each individual feeder without including interaction effects among connected feeders. Interaction effects occur as a result of linkages that exist between feeders to prevent fretting and impacting damage during normal, abnormal and accident conditions. In this paper, a 'combined' approach is adopted to include all feeders connected by inter linkages into one feeder piping model. MSC/NASTRAN finite element software was used in the stress simulation, which contains up to 127 feeder pipes. The ASME Class 1 piping analysis was conducted to investigate the effects of the linkages between feeders. Both seismic time history and broadened response spectra methods were used in the seismic stress calculation. The results show that the effect of linkages is significant in dynamic stresses for all feeder configurations, as well as in static stresses for certain feeder configurations. The single feeder analysis could either underestimate or overestimate feeder stresses depending on the pipe geometry and bend wall thickness. (authors)

Can Network Linkage Effects Determine Return? Evidence from Chinese Stock Market

Science.gov (United States)

Qiao, Haishu; Xia, Yue; Li, Ying

2016-01-01

This study used the dynamic conditional correlations (DCC) method to identify the linkage effects of Chinese stock market, and further detected the influence of network linkage effects on magnitude of security returns across different industries. Applying two physics-derived techniques, the minimum spanning tree and the hierarchical tree, we analyzed the stock interdependence within the network of the China Securities Index (CSI) industry index basket. We observed that that obvious linkage effects existed among stock networks. CII and CCE, CAG and ITH as well as COU, CHA and REI were confirmed as the core nodes in the three different networks respectively. We also investigated the stability of linkage effects by estimating the mean correlations and mean distances, as well as the normalized tree length of these indices. In addition, using the GMM model approach, we found inter-node influence within the stock network had a pronounced effect on stock returns. Our results generally suggested that there appeared to be greater clustering effect among the indexes belonging to related industrial sectors than those of diverse sectors, and network comovement was significantly affected by impactive financial events in the reality. Besides, stocks that were more central within the network of stock market usually had higher returns for compensation because they endured greater exposure to correlation risk. PMID:27257816

The DPSIR approach applied to marine eutrophication in LCIA as a learning tool

DEFF Research Database (Denmark)

Cosme, Nuno Miguel Dias; Olsen, Stig Irving

assessment and response design ultimately benefit from spatial differentiation in the results. DPSIR based on LCIA seems a useful tool to improve communication and learning, as it bridges science and management while promoting the basic elements of sustainable development in a practical educational...... eutrophication. The goal is to promote an educational example of environmental impacts assessment through science-based tools to predict the impacts, communicate knowledge and support decisions. The example builds on the (D) high demand for fixation of reactive nitrogen that supports several socio......: environmentally sustainable, technologically feasible, economically viable, socially desirable, legally permissible, and administratively achievable. Specific LCIA indicators may provide preliminary information to support a precautionary approach to act earlier on D-P and contribute to sustainability. Impacts...

A dynamic birth-death model via Intrinsic Linkage

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Robert Schoen

2013-05-01

Full Text Available BACKGROUND Dynamic population models, or models with changing vital rates, are only beginning to receive serious attention from mathematical demographers. Despite considerable progress, there is still no general analytical solution for the size or composition of a population generated by an arbitrary sequence of vital rates. OBJECTIVE The paper introduces a new approach, Intrinsic Linkage, that in many cases can analytically determine the birth trajectory of a dynamic birth-death population. METHODS Intrinsic Linkage assumes a weighted linear relationship between (i the time trajectory of proportional increases in births in a population and (ii the trajectory of the intrinsic rates of growth of the projection matrices that move the population forward in time. Flexibility is provided through choice of the weighting parameter, w, that links these two trajectories. RESULTS New relationships are found linking implied intrinsic and observed population patterns of growth. Past experience is "forgotten" through a process of simple exponential decay. When the intrinsic growth rate trajectory follows a polynomial, exponential, or cyclical pattern, the population birth trajectory can be expressed analytically in closed form. Numerical illustrations provide population values and relationships in metastable and cyclically stable models. Plausible projection matrices are typically found for a broad range of values of w, although w appears to vary greatly over time in actual populations. CONCLUSIONS The Intrinsic Linkage approach extends current techniques for dynamic modeling, revealing new relationships between population structures and the changing vital rates that generate them.

Factors controlling bacteria and protists in selected Mazurian eutrophic lakes (North-Eastern Poland) during spring

Science.gov (United States)

2013-01-01

Background The bottom-up (food resources) and top-down (grazing pressure) controls, with other environmental parameters (water temperature, pH) are the main factors regulating the abundance and structure of microbial communities in aquatic ecosystems. It is still not definitively decided which of the two control mechanisms is more important. The significance of bottom-up versus top-down controls may alter with lake productivity and season. In oligo- and/or mesotrophic environments, the bottom-up control is mostly important in regulating bacterial abundances, while in eutrophic systems, the top-down control may be more significant. Results The abundance of bacteria, heterotrophic (HNF) and autotrophic (ANF) nanoflagellates and ciliates, as well as bacterial production (BP) and metabolically active cells of bacteria (CTC, NuCC, EST) were studied in eutrophic lakes (Mazurian Lake District, Poland) during spring. The studied lakes were characterized by high nanoflagellate (mean 17.36 ± 8.57 × 103 cells ml-1) and ciliate abundances (mean 59.9 ± 22.4 ind. ml-1) that were higher in the euphotic zone than in the bottom waters, with relatively low bacterial densities (4.76 ± 2.08 × 106 cells ml-1) that were lower in the euphotic zone compared to the profundal zone. Oligotrichida (Rimostrombidium spp.), Prostomatida (Urotricha spp.) and Scuticociliatida (Histiobalantium bodamicum) dominated in the euphotic zone, whereas oligotrichs Tintinnidium sp. and prostomatids Urotricha spp. were most numerous in the bottom waters. Among the staining methods used to examine bacterial cellular metabolic activity, the lowest percentage of active cells was recorded with the CTC (1.5–15.4%) and EST (2.7–14.2%) assay in contrast to the NuCC (28.8–97.3%) method. Conclusions In the euphotic zone, the bottom-up factors (TP and DOC concentrations) played a more important role than top-down control (grazing by protists) in regulating bacterial numbers and activity

PolyUbiquitin chain linkage topology selects the functions from the underlying binding landscape.

Directory of Open Access Journals (Sweden)

Yong Wang

2014-07-01

Full Text Available Ubiquitin (Ub can generate versatile molecular signals and lead to different celluar fates. The functional poly-valence of Ub is believed to be resulted from its ability to form distinct polymerized chains with eight linkage types. To provide a full picture of ubiquitin code, we explore the binding landscape of two free Ub monomers and also the functional landscapes of of all eight linkage types by theoretical modeling. Remarkably, we found that most of the compact structures of covalently connected dimeric Ub chains (diUbs pre-exist on the binding landscape. These compact functional states were subsequently validated by corresponding linkage models. This leads to the proposal that the folding architecture of Ub monomer has encoded all functional states into its binding landscape, which is further selected by different topologies of polymeric Ub chains. Moreover, our results revealed that covalent linkage leads to symmetry breaking of interfacial interactions. We further propose that topological constraint not only limits the conformational space for effective switching between functional states, but also selects the local interactions for realizing the corresponding biological function. Therefore, the topological constraint provides a way for breaking the binding symmetry and reaching the functional specificity. The simulation results also provide several predictions that qualitatively and quantitatively consistent with experiments. Importantly, the K48 linkage model successfully predicted intermediate states. The resulting multi-state energy landscape was further employed to reconcile the seemingly contradictory experimental data on the conformational equilibrium of K48-diUb. Our results further suggest that hydrophobic interactions are dominant in the functional landscapes of K6-, K11-, K33- and K48 diUbs, while electrostatic interactions play a more important role in the functional landscapes of K27, K29, K63 and linear linkages.

PolyUbiquitin chain linkage topology selects the functions from the underlying binding landscape.

Science.gov (United States)

Wang, Yong; Tang, Chun; Wang, Erkang; Wang, Jin

2014-07-01

Ubiquitin (Ub) can generate versatile molecular signals and lead to different celluar fates. The functional poly-valence of Ub is believed to be resulted from its ability to form distinct polymerized chains with eight linkage types. To provide a full picture of ubiquitin code, we explore the binding landscape of two free Ub monomers and also the functional landscapes of of all eight linkage types by theoretical modeling. Remarkably, we found that most of the compact structures of covalently connected dimeric Ub chains (diUbs) pre-exist on the binding landscape. These compact functional states were subsequently validated by corresponding linkage models. This leads to the proposal that the folding architecture of Ub monomer has encoded all functional states into its binding landscape, which is further selected by different topologies of polymeric Ub chains. Moreover, our results revealed that covalent linkage leads to symmetry breaking of interfacial interactions. We further propose that topological constraint not only limits the conformational space for effective switching between functional states, but also selects the local interactions for realizing the corresponding biological function. Therefore, the topological constraint provides a way for breaking the binding symmetry and reaching the functional specificity. The simulation results also provide several predictions that qualitatively and quantitatively consistent with experiments. Importantly, the K48 linkage model successfully predicted intermediate states. The resulting multi-state energy landscape was further employed to reconcile the seemingly contradictory experimental data on the conformational equilibrium of K48-diUb. Our results further suggest that hydrophobic interactions are dominant in the functional landscapes of K6-, K11-, K33- and K48 diUbs, while electrostatic interactions play a more important role in the functional landscapes of K27, K29, K63 and linear linkages.

Detection of Cyanobacteria in Eutrophic Water Using a Portable Electrocoagulator and NanoGene Assay.

Science.gov (United States)

Lee, Eun-Hee; Chua, Beelee; Son, Ahjeong

2018-02-06

We have demonstrated the detection of cyanobacteria in eutrophic water samples using a portable electrocoagulator and NanoGene assay. The electrocoagulator is designed to preconcentrate cyanobacteria from water samples prior to analysis via NanoGene assay. Using Microcystis aeruginosa laboratory culture and environmental samples (cell densities ranging from 1.7 × 10 5 to 4.1 × 10 6 and 6.5 × 10 3 to 6.6 × 10 7 cells·mL -1 , respectively), the electrocoagulator was evaluated and compared with a conventional centrifuge. Varying the operation duration from 0 to 300 s with different cell densities was first investigated. Preconcentration efficiencies (obtained via absorbance measurement) and dry cell weight of preconcentrated cyanobacteria were then obtained and compared. For laboratory samples at cell densities from 3.2 × 10 5 to 4.1 × 10 6 cells·mL -1 , the preconcentration efficiencies of electrocoagulator appeared to be stable at ∼60%. At lower cell densities (1.7 and 2.2 × 10 5 cells·mL -1 ), the preconcentration efficiencies decreased to 33.9 ± 0.2 and 40.4 ± 5.4%, respectively. For environmental samples at cell densities of 2.7 × 10 5 and 6.6 × 10 7 cells·mL -1 , the electrocoagulator maintained its preconcentration efficiency at ∼60%. On the other hand, the centrifuge's preconcentration efficiencies decreased to nondetectable and below 40%, respectively. This shows that the electrocoagulator outperformed the centrifuge when using eutrophic water samples. Finally, the compatibility of the electrocoagulator with the NanoGene assay was verified via the successful detection of the microcystin synthetase D (mcyD) gene in environmental samples. The viability of the electrocoagulator as an in situ compatible alternative to the centrifuge is also discussed.

Impact of Sulfide on Nitrate Conversion in Eutrophic Nitrate-Rich Marine Sludge

DEFF Research Database (Denmark)

Schwermer, Carsten U.; Krieger, Bärbel; Lavik, Gaute

2006-01-01

IMPACT OF SULFIDE ON NITRATE CONVERSION IN EUTROPHIC NITRATE-RICH MARINE SLUDGE C.U. Schwermer 1, B.U. Krieger 2, G. Lavik 1, A. Schramm 3, J. van Rijn 4, D. de Beer 1, D. Minz 5, E. Cytryn 4, M. Kuypers 1, A. Gieseke 1 1 Max Planck Institute for Marine Microbiology, Bremen, Germany; 2 Dept...... nitrate conversion from denitrification to dissimilatory nitrate-reduction to ammonium (DNRA). In situ microsensor profiling in stagnant sludge revealed the typical stratification of nitrate reduction on top of sulfate reduction. Increasing the bulk nitrate concentration lead to a downward shift....... Our results show that the presence of sulfide generally decreased growth rates but increased N2O production. We conclude that sulfide plays a key role in causing incomplete denitrification, presumably by inhibiting the N2O reductase, and enhancing DNRA compared to denitrification.  ...

Leontief Input-Output Method for The Fresh Milk Distribution Linkage Analysis

Directory of Open Access Journals (Sweden)

Riski Nur Istiqomah

2016-11-01

Full Text Available This research discusses about linkage analysis and identifies the key sector in the fresh milk distribution using Leontief Input-Output method. This method is one of the application of Mathematics in economy. The current fresh milk distribution system includes dairy farmers →collectors→fresh milk processing industries→processed milk distributors→consumers. Then, the distribution is merged between the collectors’ axctivity and the fresh milk processing industry. The data used are primary and secondary data taken in June 2016 in Kecamatan Jabung Kabupaten Malang. The collected data are then analysed using Leontief Input-Output Matriks and Python (PYIO 2.1 software. The result is that the merging of the collectors’ and the fresh milk processing industry’s activities shows high indices of forward linkages and backward linkages. It is shown that merging of the two activities is the key sector which has an important role in developing the whole activities in the fresh milk distribution.