Stranded Specimen Data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Marine Mammal and Turtle Division collects data about individual cetaceans and sea turtles that come ashore, or strand on the beach. The date and location of...

Spatial and temporal patterns of stranded intertidal marine debris: is there a picture of global change?

Science.gov (United States)

Browne, Mark Anthony; Chapman, M Gee; Thompson, Richard C; Amaral Zettler, Linda A; Jambeck, Jenna; Mallos, Nicholas J

2015-06-16

Floating and stranded marine debris is widespread. Increasing sea levels and altered rainfall, solar radiation, wind speed, waves, and oceanic currents associated with climatic change are likely to transfer more debris from coastal cities into marine and coastal habitats. Marine debris causes economic and ecological impacts, but understanding the scope of these requires quantitative information on spatial patterns and trends in the amounts and types of debris at a global scale. There are very few large-scale programs to measure debris, but many peer-reviewed and published scientific studies of marine debris describe local patterns. Unfortunately, methods of defining debris, sampling, and interpreting patterns in space or time vary considerably among studies, yet if data could be synthesized across studies, a global picture of the problem may be avaliable. We analyzed 104 published scientific papers on marine debris in order to determine how to evaluate this. Although many studies were well designed to answer specific questions, definitions of what constitutes marine debris, the methods used to measure, and the scale of the scope of the studies means that no general picture can emerge from this wealth of data. These problems are detailed to guide future studies and guidelines provided to enable the collection of more comparable data to better manage this growing problem.

Plasmid-derived DNA Strand Displacement Gates for Implementing Chemical Reaction Networks.

Science.gov (United States)

Chen, Yuan-Jyue; Rao, Sundipta D; Seelig, Georg

2015-11-25

DNA nanotechnology requires large amounts of highly pure DNA as an engineering material. Plasmid DNA could meet this need since it is replicated with high fidelity, is readily amplified through bacterial culture and can be stored indefinitely in the form of bacterial glycerol stocks. However, the double-stranded nature of plasmid DNA has so far hindered its efficient use for construction of DNA nanostructures or devices that typically contain single-stranded or branched domains. In recent work, it was found that nicked double stranded DNA (ndsDNA) strand displacement gates could be sourced from plasmid DNA. The following is a protocol that details how these ndsDNA gates can be efficiently encoded in plasmids and can be derived from the plasmids through a small number of enzymatic processing steps. Also given is a protocol for testing ndsDNA gates using fluorescence kinetics measurements. NdsDNA gates can be used to implement arbitrary chemical reaction networks (CRNs) and thus provide a pathway towards the use of the CRN formalism as a prescriptive molecular programming language. To demonstrate this technology, a multi-step reaction cascade with catalytic kinetics is constructed. Further it is shown that plasmid-derived components perform better than identical components assembled from synthetic DNA.

Statistical Assessment of Cetacean Stranding Events in Cape Cod (Massachusetts, USA) area.

Science.gov (United States)

Zellar, R.; Pulkkinen, A. A.; Moore, K.; Reeb, D.; Karakoylu, E.; Uritskaya, O.

2017-12-01

Cetacean (whales, dolphins and porpoises) mass strandings are a longstanding mystery in the field of marine biology that continue to be recorded in coastal environments around the world. For each of these events, anywhere from a few to several hundred otherwise healthy animals strand in onshore environments, often for no apparent reason. While the causes of these events remain unclear, anthropogenic and naturogenic mechanisms have been suggested. We present results of an inter-disciplinary study that draws expertise from space weather, marine mammal biology and ecology, and marine mammal stranding response. This study assessed 16 years of cetacean stranding events in the Cape Cod (Massachusetts, USA) area concurrently with a large dataset of meteorological, geophysical, biological, oceanographic and space weather data to produce inferences about possible causes for these unexplained events.

PIR Marine Turtle Strandings

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Effective management of marine turtle data is essential to maximize their research value and enable timely population assessments and recovery monitoring. To provide...

A mass stranding of the squid martialia hyadesi Rochebrune and ...

African Journals Online (AJOL)

1997-02-11

Feb 11, 1997 ... All animals were immature, with females in lower stages of maturity than males. No predatory marine mammals were seen in the area during or after the stranding event. An interpretation of the stranding is presented with reference to historical reports of squid strandings worldwide. Evidence suggests some ...

SAKAMATA : A tool to avoid whale strandings

NARCIS (Netherlands)

Benders, F.P.A.; Beerens, S.P.; Verboom, W.C.

2004-01-01

World-wide a concern exists about the influence of man-made noise on marine life, and particularly of high power sonar. Most concern lies with marine mammals that use acoustics for hunting, communication and/or navigation. This concern is fed by recent strandings of whales that could be related to

SAKAMATA : A tool to avoid whale strandings

NARCIS (Netherlands)

Benders, F.P.A.; Beerens, S.P.; Verboom, W.C.

2002-01-01

World-wide a concern exists about the influence of man-made noise on marine life, and particularly of high power sonar. Most concern lies with marine mammals that use acoustics for hunting, communication and/or navigation. This concern is fed by recent strandings of whales that could be related to

Modeling Marine Electromagnetic Survey with Radial Basis Function Networks

Directory of Open Access Journals (Sweden)

Agus Arif

2014-11-01

Full Text Available A marine electromagnetic survey is an engineering endeavour to discover the location and dimension of a hydrocarbon layer under an ocean floor. In this kind of survey, an array of electric and magnetic receivers are located on the sea floor and record the scattered, refracted and reflected electromagnetic wave, which has been transmitted by an electric dipole antenna towed by a vessel. The data recorded in receivers must be processed and further analysed to estimate the hydrocarbon location and dimension. To conduct those analyses successfuly, a radial basis function (RBF network could be employed to become a forward model of the input-output relationship of the data from a marine electromagnetic survey. This type of neural networks is working based on distances between its inputs and predetermined centres of some basis functions. A previous research had been conducted to model the same marine electromagnetic survey using another type of neural networks, which is a multi layer perceptron (MLP network. By comparing their validation and training performances (mean-squared errors and correlation coefficients, it is concluded that, in this case, the MLP network is comparatively better than the RBF network[1].[1] This manuscript is an extended version of our previous paper, entitled Radial Basis Function Networks for Modeling Marine Electromagnetic Survey, which had been presented on 2011 International Conference on Electrical Engineering and Informatics, 17-19 July 2011, Bandung, Indonesia.

Strand displacement by DNA polymerase III occurs through a tau-psi-chi link to single-stranded DNA-binding protein coating the lagging strand template.

Science.gov (United States)

Yuan, Quan; McHenry, Charles S

2009-11-13

In addition to the well characterized processive replication reaction catalyzed by the DNA polymerase III holoenzyme on single-stranded DNA templates, the enzyme possesses an intrinsic strand displacement activity on flapped templates. The strand displacement activity is distinguished from the single-stranded DNA-templated reaction by a high dependence upon single-stranded DNA binding protein and an inability of gamma-complex to support the reaction in the absence of tau. However, if gamma-complex is present to load beta(2), a truncated tau protein containing only domains III-V will suffice. This truncated protein is sufficient to bind both the alpha subunit of DNA polymerase (Pol) III and chipsi. This is reminiscent of the minimal requirements for Pol III to replicate short single-stranded DNA-binding protein (SSB)-coated templates where tau is only required to serve as a scaffold to hold Pol III and chi in the same complex (Glover, B., and McHenry, C. (1998) J. Biol. Chem. 273, 23476-23484). We propose a model in which strand displacement by DNA polymerase III holoenzyme depends upon a Pol III-tau-psi-chi-SSB binding network, where SSB is bound to the displaced strand, stabilizing the Pol III-template interaction. The same interaction network is probably important for stabilizing the leading strand polymerase interactions with authentic replication forks. The specificity constant (k(cat)/K(m)) for the strand displacement reaction is approximately 300-fold less favorable than reactions on single-stranded templates and proceeds with a slower rate (150 nucleotides/s) and only moderate processivity (approximately 300 nucleotides). PriA, the initiator of replication restart on collapsed or misassembled replication forks, blocks the strand displacement reaction, even if added to an ongoing reaction.

Marine Vehicle Sensor Network Architecture and Protocol Designs for Ocean Observation

Directory of Open Access Journals (Sweden)

Yeqiang Shu

2012-01-01

Full Text Available The micro-scale and meso-scale ocean dynamic processes which are nonlinear and have large variability, have a significant impact on the fisheries, natural resources, and marine climatology. A rapid, refined and sophisticated observation system is therefore needed in marine scientific research. The maneuverability and controllability of mobile sensor platforms make them a preferred choice to establish ocean observing networks, compared to the static sensor observing platform. In this study, marine vehicles are utilized as the nodes of mobile sensor networks for coverage sampling of a regional ocean area and ocean feature tracking. A synoptic analysis about marine vehicle dynamic control, multi vehicles mission assignment and path planning methods, and ocean feature tracking and observing techniques is given. Combined with the observation plan in the South China Sea, we provide an overview of the mobile sensor networks established with marine vehicles, and the corresponding simulation results.

The stranding anomaly as population indicator: the case of harbour porpoise Phocoena phocoena in North-Western Europe.

Directory of Open Access Journals (Sweden)

Helene Peltier

Full Text Available Ecological indicators for monitoring strategies are expected to combine three major characteristics: ecological significance, statistical credibility, and cost-effectiveness. Strategies based on stranding networks rank highly in cost-effectiveness, but their ecological significance and statistical credibility are disputed. Our present goal is to improve the value of stranding data as population indicator as part of monitoring strategies by constructing the spatial and temporal null hypothesis for strandings. The null hypothesis is defined as: small cetacean distribution and mortality are uniform in space and constant in time. We used a drift model to map stranding probabilities and predict stranding patterns of cetacean carcasses under H0 across the North Sea, the Channel and the Bay of Biscay, for the period 1990-2009. As the most common cetacean occurring in this area, we chose the harbour porpoise Phocoena phocoena for our modelling. The difference between these strandings expected under H0 and observed strandings is defined as the stranding anomaly. It constituted the stranding data series corrected for drift conditions. Seasonal decomposition of stranding anomaly suggested that drift conditions did not explain observed seasonal variations of porpoise strandings. Long-term stranding anomalies increased first in the southern North Sea, the Channel and Bay of Biscay coasts, and finally the eastern North Sea. The hypothesis of changes in porpoise distribution was consistent with local visual surveys, mostly SCANS surveys (1994 and 2005. This new indicator could be applied to cetacean populations across the world and more widely to marine megafauna.

Applications of Wireless Sensor Networks in Marine Environment Monitoring: A Survey

Science.gov (United States)

Xu, Guobao; Shen, Weiming; Wang, Xianbin

2014-01-01

With the rapid development of society and the economy, an increasing number of human activities have gradually destroyed the marine environment. Marine environment monitoring is a vital problem and has increasingly attracted a great deal of research and development attention. During the past decade, various marine environment monitoring systems have been developed. The traditional marine environment monitoring system using an oceanographic research vessel is expensive and time-consuming and has a low resolution both in time and space. Wireless Sensor Networks (WSNs) have recently been considered as potentially promising alternatives for monitoring marine environments since they have a number of advantages such as unmanned operation, easy deployment, real-time monitoring, and relatively low cost. This paper provides a comprehensive review of the state-of-the-art technologies in the field of marine environment monitoring using wireless sensor networks. It first describes application areas, a common architecture of WSN-based oceanographic monitoring systems, a general architecture of an oceanographic sensor node, sensing parameters and sensors, and wireless communication technologies. Then, it presents a detailed review of some related projects, systems, techniques, approaches and algorithms. It also discusses challenges and opportunities in the research, development, and deployment of wireless sensor networks for marine environment monitoring. PMID:25215942

Status of marine turtle rehabilitation in Queensland

OpenAIRE

Jaylene Flint; Mark Flint; Colin James Limpus; Paul Mills

2017-01-01

Rehabilitation of marine turtles in Queensland has multifaceted objectives. It treats individual animals, serves to educate the public, and contributes to conservation. We examined the outcome from rehabilitation, time in rehabilitation, and subsequent recapture and restranding rates of stranded marine turtles between 1996 and 2013 to determine if the benefits associated with this practice are cost-effective as a conservation tool. Of 13,854 marine turtles reported as stranded during this 18-...

The assessment of marine reserve networks: guidelines for ecological evaluation: Chapter 11

Science.gov (United States)

Grorud-Colvert, Kirsten; Claudet, Joachim; Carr, Mark; Caselle, Jennifer; Day, Jon; Friedlander, Alan M.; Lester, Sarah E.; Lison de Loma, Thierry; Tissot, Brian; Malone, Dan; Claudet, Joachim

2011-01-01

As marine ecosystems are plagued by an ever-increasing suite of threats including climate change, pollution, habitat degradation, and fisheries impacts (Roessig et al., 2004; Lotze et al., 2006; Jackson, 2008), there are now no ocean areas that are exempt from anthropogenic impacts (Halpern et al., 2008). In order to preserve marine biodiversity, ecosystem function, and the goods and services provided by resistant and/or resilient systems, marine reserves have been increasingly recommended as part of an ecosystem-based approach to management (Browman and Stergiou, 2004; Levin et al., 2009). Marine reserves are defined as “areas of the ocean completely protected from all extractive and destructive activities” (Lubchenco et al., 2003) and can be experimental controls for evaluating the impact of these activities on marine ecosystems. Growing scientific information has shown consistent increases in species density, biomass, size, and diversity in response to full protection inside reserves of varying sizes and ages located in diverse regions (Claudet et al., 2008; Lester et al., 2009; Molloy et al., 2009). However, most of these data are from individual marine reserves and therefore have inherently limited transferability to networks of marine reserves, which when properly designed can outperform single marine reserves for a variety of ecological, economic, and social management goals (Roberts et al., 2003; Almany et al., 2009; Gaines et al., 2010).The concept of marine reserve networks grew out of a desire to achieve both conservation and fishery management goals by minimizing the potential negative economic, social, and cultural impacts of a single large reserve while still producing similar or even greater ecological and economic returns (Murray et al., 1999; Gaines et al., 2010). In addition, reserves networks can provide insurance by protecting areas across a region and spreading the risk that these sites may be impacted by localized catastrophes such as

Programming chemical kinetics: engineering dynamic reaction networks with DNA strand displacement

Science.gov (United States)

Srinivas, Niranjan

Over the last century, the silicon revolution has enabled us to build faster, smaller and more sophisticated computers. Today, these computers control phones, cars, satellites, assembly lines, and other electromechanical devices. Just as electrical wiring controls electromechanical devices, living organisms employ "chemical wiring" to make decisions about their environment and control physical processes. Currently, the big difference between these two substrates is that while we have the abstractions, design principles, verification and fabrication techniques in place for programming with silicon, we have no comparable understanding or expertise for programming chemistry. In this thesis we take a small step towards the goal of learning how to systematically engineer prescribed non-equilibrium dynamical behaviors in chemical systems. We use the formalism of chemical reaction networks (CRNs), combined with mass-action kinetics, as our programming language for specifying dynamical behaviors. Leveraging the tools of nucleic acid nanotechnology (introduced in Chapter 1), we employ synthetic DNA molecules as our molecular architecture and toehold-mediated DNA strand displacement as our reaction primitive. Abstraction, modular design and systematic fabrication can work only with well-understood and quantitatively characterized tools. Therefore, we embark on a detailed study of the "device physics" of DNA strand displacement (Chapter 2). We present a unified view of strand displacement biophysics and kinetics by studying the process at multiple levels of detail, using an intuitive model of a random walk on a 1-dimensional energy landscape, a secondary structure kinetics model with single base-pair steps, and a coarse-grained molecular model that incorporates three-dimensional geometric and steric effects. Further, we experimentally investigate the thermodynamics of three-way branch migration. Our findings are consistent with previously measured or inferred rates for

A Demonstration Marine Biodiversity Observation Network (MBON): Understanding Marine Life and its Role in Maintaining Ecosystem Services

Science.gov (United States)

Muller-Karger, F. E.; Iken, K.; Miller, R. J.; Duffy, J. E.; Chavez, F.; Montes, E.

2016-02-01

The U.S. Federal government (NOAA, NASA, BOEM, and the Smithsonian Institution), academic researchers, and private partners are laying the foundation for a Marine Biodiversity Observation Network (MBON). The goals of the network are to: 1) Observe and understand life, from microbes to whales, in different coastal and continental shelf habitats; 2) Define an efficient set of observations required for implementing a useful MBON; 3) Develop technology for biodiversity assessments including emerging environmental DNA (eDNA), remote sensing, and image analysis methods to coordinate with classical sampling; 4) Integrate and synthesize information in coordination with the Integrated Ocean Observing System (IOOS), the international Group on Earth Observations Biodiversity Observation Network(GEO BON), and the Ocean Biogeographic Information System (OBIS) sponsored by UNESCO's Intergovernmental Oceanographic Commission (IOC); and 5) Understand the linkages between marine biodiversity, ecosystem processes, and the social-economic context of a region. Pilot projects have been implemented within three NOAA National Marine Sanctuaries (Florida Keys, Monterey Bay, and Channel Islands), the wider Santa Barbara Channel, in the Chukchi Sea, and through the Smithsonian's Tennenbaum Marine Observatories Network (TMON) at several sites in the U.S. and collaborating countries. Together, these MBON sites encompass a wide range of marine environments, including deep sea, continental shelves, and coastal habitats including estuaries, wetlands, and coral reefs. The present MBON partners are open to growth of the MBON through additional collaborations. Given these initiatives, GEO BON is proposing an MBON effort that spans from pole to pole, with a pathfinder effort among countries in the Americas. By specializing in coastal ecosystems—where marine biodiversity and people are concentrated and interact most—the MBON and TMON initiatives aim to provide policymakers with the science to

A Multi-Objective Partition Method for Marine Sensor Networks Based on Degree of Event Correlation

OpenAIRE

Dongmei Huang; Chenyixuan Xu; Danfeng Zhao; Wei Song; Qi He

2017-01-01

Existing marine sensor networks acquire data from sea areas that are geographically divided, and store the data independently in their affiliated sea area data centers. In the case of marine events across multiple sea areas, the current network structure needs to retrieve data from multiple data centers, and thus severely affects real-time decision making. In this study, in order to provide a fast data retrieval service for a marine sensor network, we use all the marine sensors as the vertice...

AMBON - the Arctic Marine Biodiversity Observing Network

Science.gov (United States)

Iken, K.; Danielson, S. L.; Grebmeier, J. M.; Cooper, L. W.; Hopcroft, R. R.; Kuletz, K.; Stafford, K.; Mueter, F. J.; Collins, E.; Bluhm, B.; Moore, S. E.; Bochenek, R. J.

2016-02-01

The goal of the Arctic Marine Biodiversity Observing Network (AMBON) is to build an operational and sustainable marine biodiversity observing network for the US Arctic Chukchi Sea continental shelf. The AMBON has four main goals: 1. To close current gaps in taxonomic biodiversity observations from microbes to whales, 2. To integrate results of past and ongoing research programs on the US Arctic shelf into a biodiversity observation network, 3. To demonstrate at a regional level how an observing network could be developed, and 4. To link with programs on the pan-Arctic to global scale. The AMBON fills taxonomic (from microbes to mammals), functional (food web structure), spatial and temporal (continuing time series) gaps, and includes new technologies such as state-of-the-art genomic tools, with biodiversity and environmental observations linked through central data management through the Alaska Ocean Observing System. AMBON is a 5-year partnership between university and federal researchers, funded through the National Ocean Partnership Program (NOPP), with partners in the National Oceanographic and Atmospheric Administration (NOAA), the Bureau of Ocean and Energy Management (BOEM), and Shell industry. AMBON will allow us to better coordinate, sustain, and synthesize biodiversity research efforts, and make data available to a broad audience of users, stakeholders, and resource managers.

The Smithsonian-led Marine Global Earth Observatory (MarineGEO): Proposed Model for a Collaborative Network Linking Marine Biodiversity to Ecosystem Processes

Science.gov (United States)

Duffy, J. E.

2016-02-01

Biodiversity - the variety of functional types of organisms - is the engine of marine ecosystem processes, including productivity, nutrient cycling, and carbon sequestration. Biodiversity remains a black box in much of ocean science, despite wide recognition that effectively managing human interactions with marine ecosystems requires understanding both structure and functional consequences of biodiversity. Moreover, the inherent complexity of biological systems puts a premium on data-rich, comparative approaches, which are best met via collaborative networks. The Smithsonian Institution's MarineGEO program links a growing network of partners conducting parallel, comparative research to understand change in marine biodiversity and ecosystems, natural and anthropogenic drivers of that change, and the ecological processes mediating it. The focus is on nearshore, seabed-associated systems where biodiversity and human population are concentrated and interact most, yet which fall through the cracks of existing ocean observing programs. MarineGEO offers a standardized toolbox of research modules that efficiently capture key elements of biological diversity and its importance in ecological processes across a range of habitats. The toolbox integrates high-tech (DNA-based, imaging) and low-tech protocols (diver surveys, rapid assays of consumer activity) adaptable to differing institutional capacity and resources. The model for long-term sustainability involves leveraging in-kind support among partners, adoption of best practices wherever possible, engagement of students and citizen scientists, and benefits of training, networking, and global relevance as incentives for participation. Here I highlight several MarineGEO comparative research projects demonstrating the value of standardized, scalable assays and parallel experiments for measuring fish and invertebrate diversity, recruitment, benthic herbivory and generalist predation, decomposition, and carbon sequestration. Key

Marine Spatial Planning in a Transboundary Context: Linking Baja California with California's Network of Marine Protected Areas

Directory of Open Access Journals (Sweden)

Nur Arafeh-Dalmau

2017-05-01

Full Text Available It is acknowledged that an effective path to globally protect marine ecosystems is through the establishment of eco-regional scale networks of MPAs spanning across national frontiers. In this work we aimed to plan for regionally feasible networks of MPAs that can be ecologically linked with an existing one in a transboundary context. We illustrate our exercise in the Ensenadian eco-region, a shared marine ecosystem between the south of California, United States of America (USA, and the north of Baja California, Mexico; where conservation actions differ across the border. In the USA, California recently established a network of MPAs through the Marine Life Protection Act (MLPA, while in Mexico: Baja California lacks a network of MPAs or a marine spatial planning effort to establish it. We generated four different scenarios with Marxan by integrating different ecological, social, and management considerations (habitat representation, opportunity costs, habitat condition, and enforcement costs. To do so, we characterized and collected biophysical and socio-economic information for Baja California and developed novel approaches to quantify and incorporate some of these considerations. We were able to design feasible networks of MPAs in Baja California that are ecologically linked with California's network (met between 78.5 and 84.4% of the MLPA guidelines and that would represent a low cost for fishers and aquaculture investors. We found that when multiple considerations are integrated more priority areas for conservation emerge. For our region, human distribution presents a strong gradient from north to south and resulted to be an important factor for the spatial arrangement of the priority areas. This work shows how, despite the constraints of a data-poor area, the available conservation principles, mapping, and planning tools can still be used to generate spatial conservation plans in a transboundary context.

Status of marine turtle rehabilitation in Queensland

Directory of Open Access Journals (Sweden)

Jaylene Flint

2017-03-01

Full Text Available Rehabilitation of marine turtles in Queensland has multifaceted objectives. It treats individual animals, serves to educate the public, and contributes to conservation. We examined the outcome from rehabilitation, time in rehabilitation, and subsequent recapture and restranding rates of stranded marine turtles between 1996 and 2013 to determine if the benefits associated with this practice are cost-effective as a conservation tool. Of 13,854 marine turtles reported as stranded during this 18-year period, 5,022 of these turtles were stranded alive with the remainder verified as dead or of unknown condition. A total of 2,970 (59% of these live strandings were transported to a rehabilitation facility. Overall, 1,173/2,970 (39% turtles were released over 18 years, 101 of which were recaptured: 77 reported as restrandings (20 dead, 13 alive subsequently died, 11 alive subsequently euthanized, 33 alive and 24 recaptured during normal marine turtle population monitoring or fishing activities. Of the turtles admitted to rehabilitation exhibiting signs of disease, 88% of them died, either unassisted or by euthanasia and 66% of turtles admitted for unknown causes of stranding died either unassisted or by euthanasia. All turtles recorded as having a buoyancy disorder with no other presenting problem or disorder recorded, were released alive. In Queensland, rehabilitation costs approximately $1,000 per animal per year admitted to a center, $2,583 per animal per year released, and $123,750 per animal per year for marine turtles which are presumably successfully returned to the functional population. This practice may not be economically viable in its present configuration, but may be more cost effective as a mobile response unit. Further there is certainly benefit giving individual turtles a chance at survival and educating the public in the perils facing marine turtles. As well, rehabilitation can provide insight into the diseases and environmental

Status of marine turtle rehabilitation in Queensland.

Science.gov (United States)

Flint, Jaylene; Flint, Mark; Limpus, Colin James; Mills, Paul

2017-01-01

Rehabilitation of marine turtles in Queensland has multifaceted objectives. It treats individual animals, serves to educate the public, and contributes to conservation. We examined the outcome from rehabilitation, time in rehabilitation, and subsequent recapture and restranding rates of stranded marine turtles between 1996 and 2013 to determine if the benefits associated with this practice are cost-effective as a conservation tool. Of 13,854 marine turtles reported as stranded during this 18-year period, 5,022 of these turtles were stranded alive with the remainder verified as dead or of unknown condition. A total of 2,970 (59%) of these live strandings were transported to a rehabilitation facility. Overall, 1,173/2,970 (39%) turtles were released over 18 years, 101 of which were recaptured: 77 reported as restrandings (20 dead, 13 alive subsequently died, 11 alive subsequently euthanized, 33 alive) and 24 recaptured during normal marine turtle population monitoring or fishing activities. Of the turtles admitted to rehabilitation exhibiting signs of disease, 88% of them died, either unassisted or by euthanasia and 66% of turtles admitted for unknown causes of stranding died either unassisted or by euthanasia. All turtles recorded as having a buoyancy disorder with no other presenting problem or disorder recorded, were released alive. In Queensland, rehabilitation costs approximately $1,000 per animal per year admitted to a center, $2,583 per animal per year released, and $123,750 per animal per year for marine turtles which are presumably successfully returned to the functional population. This practice may not be economically viable in its present configuration, but may be more cost effective as a mobile response unit. Further there is certainly benefit giving individual turtles a chance at survival and educating the public in the perils facing marine turtles. As well, rehabilitation can provide insight into the diseases and environmental stressors causing

Status of marine turtle rehabilitation in Queensland

Science.gov (United States)

Flint, Mark; Limpus, Colin James; Mills, Paul

2017-01-01

Rehabilitation of marine turtles in Queensland has multifaceted objectives. It treats individual animals, serves to educate the public, and contributes to conservation. We examined the outcome from rehabilitation, time in rehabilitation, and subsequent recapture and restranding rates of stranded marine turtles between 1996 and 2013 to determine if the benefits associated with this practice are cost-effective as a conservation tool. Of 13,854 marine turtles reported as stranded during this 18-year period, 5,022 of these turtles were stranded alive with the remainder verified as dead or of unknown condition. A total of 2,970 (59%) of these live strandings were transported to a rehabilitation facility. Overall, 1,173/2,970 (39%) turtles were released over 18 years, 101 of which were recaptured: 77 reported as restrandings (20 dead, 13 alive subsequently died, 11 alive subsequently euthanized, 33 alive) and 24 recaptured during normal marine turtle population monitoring or fishing activities. Of the turtles admitted to rehabilitation exhibiting signs of disease, 88% of them died, either unassisted or by euthanasia and 66% of turtles admitted for unknown causes of stranding died either unassisted or by euthanasia. All turtles recorded as having a buoyancy disorder with no other presenting problem or disorder recorded, were released alive. In Queensland, rehabilitation costs approximately $1,000 per animal per year admitted to a center, $2,583 per animal per year released, and $123,750 per animal per year for marine turtles which are presumably successfully returned to the functional population. This practice may not be economically viable in its present configuration, but may be more cost effective as a mobile response unit. Further there is certainly benefit giving individual turtles a chance at survival and educating the public in the perils facing marine turtles. As well, rehabilitation can provide insight into the diseases and environmental stressors causing

A Multi-Objective Partition Method for Marine Sensor Networks Based on Degree of Event Correlation

Directory of Open Access Journals (Sweden)

Dongmei Huang

2017-09-01

Full Text Available Existing marine sensor networks acquire data from sea areas that are geographically divided, and store the data independently in their affiliated sea area data centers. In the case of marine events across multiple sea areas, the current network structure needs to retrieve data from multiple data centers, and thus severely affects real-time decision making. In this study, in order to provide a fast data retrieval service for a marine sensor network, we use all the marine sensors as the vertices, establish the edge based on marine events, and abstract the marine sensor network as a graph. Then, we construct a multi-objective balanced partition method to partition the abstract graph into multiple regions and store them in the cloud computing platform. This method effectively increases the correlation of the sensors and decreases the retrieval cost. On this basis, an incremental optimization strategy is designed to dynamically optimize existing partitions when new sensors are added into the network. Experimental results show that the proposed method can achieve the optimal layout for distributed storage in the process of disaster data retrieval in the China Sea area, and effectively optimize the result of partitions when new buoys are deployed, which eventually will provide efficient data access service for marine events.

A Multi-Objective Partition Method for Marine Sensor Networks Based on Degree of Event Correlation.

Science.gov (United States)

Huang, Dongmei; Xu, Chenyixuan; Zhao, Danfeng; Song, Wei; He, Qi

2017-09-21

Existing marine sensor networks acquire data from sea areas that are geographically divided, and store the data independently in their affiliated sea area data centers. In the case of marine events across multiple sea areas, the current network structure needs to retrieve data from multiple data centers, and thus severely affects real-time decision making. In this study, in order to provide a fast data retrieval service for a marine sensor network, we use all the marine sensors as the vertices, establish the edge based on marine events, and abstract the marine sensor network as a graph. Then, we construct a multi-objective balanced partition method to partition the abstract graph into multiple regions and store them in the cloud computing platform. This method effectively increases the correlation of the sensors and decreases the retrieval cost. On this basis, an incremental optimization strategy is designed to dynamically optimize existing partitions when new sensors are added into the network. Experimental results show that the proposed method can achieve the optimal layout for distributed storage in the process of disaster data retrieval in the China Sea area, and effectively optimize the result of partitions when new buoys are deployed, which eventually will provide efficient data access service for marine events.

Pacific Island Network Marine Fish Monitoring Dataset - Transects

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The benthic marine community in the Pacific Island Network (PACN) is a complex ecologic system and a diverse taxonomic environment, including algae and corals and...

Polybrominated diphenyl ethers in pinnipeds stranded along the southern California coast

Energy Technology Data Exchange (ETDEWEB)

Meng Xiangzhou [Southern California Coastal Water Research Project, 3535 Harbor Blvd, Suite 110, Costa Mesa, CA 92626 (United States); Blasius, Mary Ellen; Gossett, Richard W. [Institute for Integrated Research in Materials, Environments and Society (IIRMES), California State University, Long Beach, 1250 Bellflower Blvd, Long Beach, CA 90840 (United States); Maruya, Keith A., E-mail: keithm@sccwrp.or [Southern California Coastal Water Research Project, 3535 Harbor Blvd, Suite 110, Costa Mesa, CA 92626 (United States)

2009-10-15

Little to no information exists for polybrominated diphenyl ethers (PBDEs) in marine mammals frequenting the highly urbanized southern California (USA) coast. Fourteen PBDE congeners were determined by GC-ECNI-MS in blubber of pinnipeds stranded locally between 1994 and 2006. Total PBDE concentrations (SIGMAPBDE) in California sea lion (n = 63) ranged from 0.04 to 33.7 mug/g wet weight (mean: 5.24 mug/g). To our knowledge, these are the highest reported PBDE levels in marine mammals to date. By comparison, mean SIGMAPBDE in Pacific harbor seals (n = 9) and northern elephant seals (n = 16) were 0.96 and 0.09 mug/g, respectively. PBDEs in adult males were higher than for adult females, however, no age class differences or temporal trends were observed. As the first PBDE data reported for marine mammals in this region, the elevated levels underscore the need for additional studies on the sources, temporal trends, and potential effects of PBDEs in highly urbanized coastal zones. - Levels of PBDEs in pinnipeds found stranded along the southern California coast (USA) between 1994 and 2006 are the highest reported to date for marine mammals.

Polybrominated diphenyl ethers in pinnipeds stranded along the southern California coast

International Nuclear Information System (INIS)

Meng Xiangzhou; Blasius, Mary Ellen; Gossett, Richard W.; Maruya, Keith A.

2009-01-01

Little to no information exists for polybrominated diphenyl ethers (PBDEs) in marine mammals frequenting the highly urbanized southern California (USA) coast. Fourteen PBDE congeners were determined by GC-ECNI-MS in blubber of pinnipeds stranded locally between 1994 and 2006. Total PBDE concentrations (ΣPBDE) in California sea lion (n = 63) ranged from 0.04 to 33.7 μg/g wet weight (mean: 5.24 μg/g). To our knowledge, these are the highest reported PBDE levels in marine mammals to date. By comparison, mean ΣPBDE in Pacific harbor seals (n = 9) and northern elephant seals (n = 16) were 0.96 and 0.09 μg/g, respectively. PBDEs in adult males were higher than for adult females, however, no age class differences or temporal trends were observed. As the first PBDE data reported for marine mammals in this region, the elevated levels underscore the need for additional studies on the sources, temporal trends, and potential effects of PBDEs in highly urbanized coastal zones. - Levels of PBDEs in pinnipeds found stranded along the southern California coast (USA) between 1994 and 2006 are the highest reported to date for marine mammals.

European Marine Observation and Data Network EMODnet Physics

Directory of Open Access Journals (Sweden)

Antonio Novellino

2014-10-01

Full Text Available Recently the European Commission undertook steps towards a European Marine Observation and Data Network (EMODnet in order to standardize method for observing and assessing the grade of the Member States seas and improve access to high quality data. Since 2008-2009, European Commission, represented by the Directorate-General for Maritime Affairs and Fisheries (DG MARE, is running several service contracts for creating pilot thematic components of the ur-EMODNET: Biology, Bathymetry, Chemistry, Geology, Habitats, and Physics.The existing EMODnet-Physics portal (www.emodnet-physics.eu is based on a strong collaboration between EuroGOOS member institutes and its regional operational oceanographic systems (ROOSs, and the National Oceanographic Data Centres (NODCs, and it is a marine observation information system. It includes systems for physical data from the whole Europe (wave height andperiod, temperature of the water column, wind speed and direction, salinity of the water column, horizontal velocity of the water column, light attenuation, and sea level provided mainly by fixed stations and ferry-box platforms, discovering related data sets (both near real time and historical data sets, viewing and downloading of the data from about 2100 platforms (www.emodnetphysics.eu/map and thus contributing towards the definition of an operational European Marine Observation and Data Network (EMODnet.

Diversity and Inclusion in Conservation: A Proposal for a Marine Diversity Network

Directory of Open Access Journals (Sweden)

Nicola S. Smith

2017-08-01

Full Text Available Low diversity among scientists and practitioners is rampant in conservation. Currently, conservation professionals do not reflect the same diversity of perspectives and experiences of the world as the communities who bear the largest burden for implementing—or adverse consequences for failing to implement—conservation action. Acknowledging and describing the problem is important. But policies and programmes must also be put in place to correct it. Here, we highlight some measurable benefits of workforce diversity, and give an overview of some of the barriers to inclusion in marine conservation that help perpetuate low workforce diversity. Importantly, we underscore actions that both individuals and groups can take to alleviate such barriers. In particular, we describe the establishment of an online Marine Diversity Network, which conference participants proposed during a focus group meeting at the 4th International Marine Conservation Congress. The network will serve to bring together people from across the globe, from a variety of backgrounds, and from all career stages, to share knowledge, experiences and ideas, to provide and receive mentorship in marine conservation, and to forge new collaborations. Removing barriers to diverse participation requires coordinated, mindful actions by individuals and organizations. We hope that the proposed network and other actions presented in this paper find widespread support, and that they might serve both as inspiration and guide to other groups concerned with increasing diversity and inclusivity.

Emerging marine protected area networks in the coral triangle: Lessons and way forward

Directory of Open Access Journals (Sweden)

Stuart J Green

2011-01-01

Full Text Available Marine protected areas (MPAs and MPA networks are valuable tools for protecting coral reef habitats and managing near-shore fisheries, while playing an essential role in the overall conservation of marine biodiversity. In addition, MPAs and their networks are often the core strategy for larger scale and more integrated forms of marine resource management that can lead to ecosystem-based management regimes for seascapes and eco-regions. This study conducted in 2008 documents the status of selected MPAs and MPA networks in Indonesia, Philippines and Papua New Guinea, to better understand development and their level of success in the Coral Triangle. Findings reveal that substantial gaps exist between the theory and practice of creating functional MPA networks. Across these sites, biophysical and social science knowledge, required to build functional and effective MPAs or MPA networks, lagged behind substantially. Aspects that appeared to require the most attention to improve MPA network effectiveness included essential management systems, institutional arrangements, governance and sustainable financing. Common indicators of success such as increased fish catch and habitat quality parameters were consistently associated with several independent variables: sustainable financing for management, clarity of MPA network rules, enforcement by community level enforcers, local skills development, and involvement in management by local elected politicians, a functional management board, multi-stakeholder planning mechanisms and participatory biophysical assessments. Conclusions are that although considerable investments have been made in MPAs and potential MPA networks in the Coral Triangle, management effectiveness is generally poor throughout the region and that not many large, formally declared MPAs are well managed.

European Marine Biodiversity Monitoring Networks: strengths, weaknesses, opportunities and threats

Directory of Open Access Journals (Sweden)

Joana Patrício

2016-09-01

Full Text Available By 2020, European Union Member States should achieve Good Environmental Status (GES for eleven environmental quality descriptors for their marine waters to fulfill the Marine Strategy Framework Directive (MSFD. By the end of 2015, in coordination with the Regional Seas Conventions, each EU Member States was required to develop a marine strategy for their waters, together with other countries within the same marine region or sub-region. Coherent monitoring programs, submitted in 2014, form a key component of this strategy, which then aimed to lead to a Program of Measures (submitted in 2015. The European DEVOTES FP7 project has produced and interrogated a catalogue of EU marine monitoring related to MSFD descriptors 1 (biological diversity, 2 (non-indigenous species, 4 (food webs and 6 (seafloor integrity. Here we detail the monitoring activity at the regional and sub-regional level for these descriptors, as well as for 11 biodiversity components, 22 habitats and the 37 anthropogenic pressures addressed. The metadata collated for existing European monitoring networks were subject to a SWOT (strengths, weaknesses, opportunities and threats analysis. This interrogation has indicated case studies to address the following questions: a what are the types of monitoring currently in place?; b who does what and how?; c is the monitoring fit-for-purpose for addressing the MSFD requirements?, and d what are the impediments to better monitoring (e.g. costs, shared responsibilities between countries, overlaps, co-ordination? We recommend the future means, to overcome the identified impediments and develop more robust monitoring strategies and as such the results are especially relevant to implementing coordinated monitoring networks throughout Europe, for marine policy makers, government agencies and regulatory bodies. It is emphasized that while many of the recommendations given here require better, more extensive and perhaps more costly monitoring, this is

Rescue, rehabilitation, and release of marine mammals: An analysis of current views and practices.

OpenAIRE

St. Aubin, David J.; Geraci, Joseph R.; Lounsbury, Valerie J.

1996-01-01

Stranded marine mammals have long attracted public attention. Those that wash up dead are, for all their value to science, seldom seen by the public as more than curiosities. Animals that are sick, injured, orphaned or abandoned ignite a different response. Generally, public sentiment supports any effort to rescue, treat and return them to sea. Institutions displaying marine mammals showed an early interest in live-stranded animals as a source of specimens -- in 1948, Marine Studios in...

Ingestion of marine litter by loggerhead sea turtles, Caretta caretta, in Portuguese continental waters.

Science.gov (United States)

Nicolau, Lídia; Marçalo, Ana; Ferreira, Marisa; Sá, Sara; Vingada, José; Eira, Catarina

2016-02-15

The accumulation of litter in marine and coastal environments is a major threat to marine life. Data on marine litter in the gastrointestinal tract of stranded loggerhead turtles, Caretta caretta, found along the Portuguese continental coast was presented. Out of the 95 analysed loggerheads, litter was present in 56 individuals (59.0%) and most had less than 10 litter items (76.8%) and less than 5 g (dm) (96.8%). Plastic was the main litter category (frequency of occurrence=56.8%), while sheet (45.3%) was the most relevant plastic sub-category. There was no influence of loggerhead stranding season, cause of stranding or size on the amount of litter ingested (mean number and dry mass of litter items per turtle). The high ingested litter occurrence frequency in this study supports the use of the loggerhead turtle as a suitable tool to monitor marine litter trends, as required by the European Marine Strategy Framework Directive. Copyright © 2015 Elsevier Ltd. All rights reserved.

Changes in fish assemblages following the establishment of a network of no-take marine reserves and partially-protected areas.

Directory of Open Access Journals (Sweden)

Brendan P Kelaher

Full Text Available Networks of no-take marine reserves and partially-protected areas (with limited fishing are being increasingly promoted as a means of conserving biodiversity. We examined changes in fish assemblages across a network of marine reserves and two different types of partially-protected areas within a marine park over the first 5 years of its establishment. We used Baited Remote Underwater Video (BRUV to quantify fish communities on rocky reefs at 20-40 m depth between 2008-2011. Each year, we sampled 12 sites in 6 no-take marine reserves and 12 sites in two types of partially-protected areas with contrasting levels of protection (n = 4 BRUV stations per site. Fish abundances were 38% greater across the network of marine reserves compared to the partially-protected areas, although not all individual reserves performed equally. Compliance actions were positively associated with marine reserve responses, while reserve size had no apparent relationship with reserve performance after 5 years. The richness and abundance of fishes did not consistently differ between the two types of partially-protected areas. There was, therefore, no evidence that the more regulated partially-protected areas had additional conservation benefits for reef fish assemblages. Overall, our results demonstrate conservation benefits to fish assemblages from a newly established network of temperate marine reserves. They also show that ecological monitoring can contribute to adaptive management of newly established marine reserve networks, but the extent of this contribution is limited by the rate of change in marine communities in response to protection.

Measures of Auditory Function in Stranded Marine Mammals

National Research Council Canada - National Science Library

Ketten, Darlene

2000-01-01

.... Behavioral measures, which consist of simple yes-no replies to a sound stimulus, are possible in trained marine mammals but are not applicable to the large number and diverse species of wild animals...

Indications of marine bioinvasion from network theory. An analysis of the global cargo ship network

NARCIS (Netherlands)

Kölzsch, A.; Blasius, B.

2011-01-01

The transport of huge amounts of small aquatic organisms in the ballast tanks and at the hull of large cargo ships leads to ever increasing rates of marine bioinvasion. In this study, we apply a network theoretic approach to examine the introduction of invasive species into new ports by global

Command Filtered Adaptive Fuzzy Neural Network Backstepping Control for Marine Power System

Directory of Open Access Journals (Sweden)

Xin Zhang

2014-01-01

Full Text Available In order to retrain chaotic oscillation of marine power system which is excited by periodic electromagnetism perturbation, a novel command-filtered adaptive fuzzy neural network backstepping control method is designed. First, the mathematical model of marine power system is established based on the two parallel nonlinear model. Then, main results of command-filtered adaptive fuzzy neural network backstepping control law are given. And the Lyapunov stability theory is applied to prove that the system can remain closed-loop asymptotically stable with this controller. Finally, simulation results indicate that the designed controller can suppress chaotic oscillation with fast convergence speed that makes the system return to the equilibrium point quickly; meanwhile, the parameter which induces chaotic oscillation can also be discriminated.

SE Marine Mammal Histology/Tissue data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Tissue samples are collected from stranded marine mammals in the Southeastern United States. These tissue samples are examined histologically and evaluated to...

INFOMAR - Ireland's National Seabed Mapping Programme: A Tool For Marine Spatial Planning

Science.gov (United States)

Furey, T. M.

2016-02-01

INFOMAR is Ireland's national seabed mapping programme and is a key action in the national integrated marine plan, Harnessing Our Ocean Wealth. It comprises a multi-platform approach to delivering marine integrated mapping in 2 phases, over a projected 20 year timeline (2006-2026). The programme has three work strands; Data Acquisition, Data Exchange and Integration, and Value Added Exploitation. The Data Acquisition strand includes collection of hydrographic, oceanographic, geological, habitat and heritage datasets that will underpin future sustainable development and management of Ireland's marine resource. INFOMAR outputs are delivered through the Data Exchange and Integration strand. Uses of these outputs are wide ranging and multipurpose, from management plans for fisheries, aquaculture and coastal protection works, to environmental impact assessments, ocean renewable development and integrated coastal zone management. In order to address the evolution and diversification of maritime user requirements, the programme has realigned and developed outputs and new products, in part, through an innovative research funding initiative. Development is also fostered through the Value Added Exploitation strand. INFOMAR outputs and products serve to underpin delivery of Ireland's statutory obligations and enhance compliance with EU and national legislation. This is achieved through co-operation with the agencies responsible for supporting Ireland's international obligations and for the implementation of marine spatial planning. A strategic national seabed mapping programme such as INFOMAR, provides a critical baseline dataset which underpins development of the marine economy, and improves our understanding of the response of marine systems to pressures, and the effect of cumulative impacts. This paper will focus on the evolution and scope of INFOMAR, and look at examples of outputs being harnessed to serve approaches to the management of activities having an impact on the

STEADY STATE PERFORMANCES ANALYSIS OF MODERN MARINE TWO-STROKE LOW SPEED DIESEL ENGINE USING MLP NEURAL NETWORK MODEL

Directory of Open Access Journals (Sweden)

Ozren Bukovac

2016-01-01

Full Text Available Compared to the other marine engines for ship propulsion, turbocharged two-stroke low speed diesel engines have advantages due to their high efficiency and reliability. Modern low speed ”intelligent” marine diesel engines have a flexibility in its operation due to the variable fuel injection strategy and management of the exhaust valve drive. This paper carried out verified zerodimensional numerical simulations which have been used for MLP (Multilayer Perceptron neural network predictions of marine two-stroke low speed diesel engine steady state performances. The developed MLP neural network was used for marine engine optimized operation control. The paper presents an example of achieving lowest specific fuel consumption and for minimization of the cylinder process highest temperature for reducing NOx emission. Also, the developed neural network was used to achieve optimal exhaust gases heat flow for utilization. The obtained data maps give insight into the optimal working areas of simulated marine diesel engine, depending on the selected start of the fuel injection (SOI and the time of the exhaust valve opening (EVO.

European Marine Observation and Data Network EMODnet Physics

Directory of Open Access Journals (Sweden)

Antonio Novellino

2014-10-01

period, temperature of the water column, wind speed and direction, salinity of the water column, horizontal velocity of the water column, light attenuation, and sea level provided mainly by fixed stations and ferry-box platforms, discovering related data sets (both near real time and historical data sets, viewing and downloading of the data from about 2100 platforms (www.emodnetphysics.eu/map and thus contributing towards the definition of an operational European Marine Observation and Data Network (EMODnet.

Towards quantitative viromics for both double-stranded and single-stranded DNA viruses

Directory of Open Access Journals (Sweden)

Simon Roux

2016-12-01

Full Text Available Background Viruses strongly influence microbial population dynamics and ecosystem functions. However, our ability to quantitatively evaluate those viral impacts is limited to the few cultivated viruses and double-stranded DNA (dsDNA viral genomes captured in quantitative viral metagenomes (viromes. This leaves the ecology of non-dsDNA viruses nearly unknown, including single-stranded DNA (ssDNA viruses that have been frequently observed in viromes, but not quantified due to amplification biases in sequencing library preparations (Multiple Displacement Amplification, Linker Amplification or Tagmentation. Methods Here we designed mock viral communities including both ssDNA and dsDNA viruses to evaluate the capability of a sequencing library preparation approach including an Adaptase step prior to Linker Amplification for quantitative amplification of both dsDNA and ssDNA templates. We then surveyed aquatic samples to provide first estimates of the abundance of ssDNA viruses. Results Mock community experiments confirmed the biased nature of existing library preparation methods for ssDNA templates (either largely enriched or selected against and showed that the protocol using Adaptase plus Linker Amplification yielded viromes that were ±1.8-fold quantitative for ssDNA and dsDNA viruses. Application of this protocol to community virus DNA from three freshwater and three marine samples revealed that ssDNA viruses as a whole represent only a minor fraction (<5% of DNA virus communities, though individual ssDNA genomes, both eukaryote-infecting Circular Rep-Encoding Single-Stranded DNA (CRESS-DNA viruses and bacteriophages from the Microviridae family, can be among the most abundant viral genomes in a sample. Discussion Together these findings provide empirical data for a new virome library preparation protocol, and a first estimate of ssDNA virus abundance in aquatic systems.

Anticipating changes to future connectivity within a network of marine protected areas.

Science.gov (United States)

Coleman, Melinda A; Cetina-Heredia, Paulina; Roughan, Moninya; Feng, Ming; van Sebille, Erik; Kelaher, Brendan P

2017-09-01

Continental boundary currents are projected to be altered under future scenarios of climate change. As these currents often influence dispersal and connectivity among populations of many marine organisms, changes to boundary currents may have dramatic implications for population persistence. Networks of marine protected areas (MPAs) often aim to maintain connectivity, but anticipation of the scale and extent of climatic impacts on connectivity are required to achieve this critical conservation goal in a future of climate change. For two key marine species (kelp and sea urchins), we use oceanographic modelling to predict how continental boundary currents are likely to change connectivity among a network of MPAs spanning over 1000 km of coastline off the coast of eastern Australia. Overall change in predicted connectivity among pairs of MPAs within the network did not change significantly over and above temporal variation within climatic scenarios, highlighting the need for future studies to incorporate temporal variation in dispersal to robustly anticipate likely change. However, the intricacies of connectivity between different pairs of MPAs were noteworthy. For kelp, poleward connectivity among pairs of MPAs tended to increase in the future, whereas equatorward connectivity tended to decrease. In contrast, for sea urchins, connectivity among pairs of MPAs generally decreased in both directions. Self-seeding within higher-latitude MPAs tended to increase, and the role of low-latitude MPAs as a sink for urchins changed significantly in contrasting ways. These projected changes have the potential to alter important genetic parameters with implications for adaptation and ecosystem vulnerability to climate change. Considering such changes, in the context of managing and designing MPA networks, may ensure that conservation goals are achieved into the future. © 2017 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

Contribution of Charges in Polyvinyl Alcohol Networks to Marine Antifouling.

Science.gov (United States)

Yang, Wufang; Lin, Peng; Cheng, Daocang; Zhang, Longzhou; Wu, Yang; Liu, Yupeng; Pei, Xiaowei; Zhou, Feng

2017-05-31

Semi-interpenetrated polyvinyl alcohol polymer networks (SIPNs) were prepared by integrating various charged components into polyvinyl alcohol polymer. Contact angle measurement, attenuated total reflection Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and tensile tests were used to characterize the physicochemical properties of the prepared SIPNs. To investigate the contribution of charges to marine antifouling, the adhesion behaviors of green algae Dunaliella tertiolecta and diatoms Navicula sp. in the laboratory and of the actual marine animals in field test were studied for biofouling assays. The results suggest that less algae accumulation densities are observed for neutral-, anionic-, and zwitterionic-component-integrated SIPNs. However, for the cationic SIPNs, despite the hydration shell induced by the ion-dipole interaction, the resistance to biofouling largely depends on the amount of cationic component because of the possible favorable electrostatic attraction between the cationic groups in SIPNs and the negatively charged algae. Considering that the preparation of novel nontoxic antifouling coating is a long-standing and cosmopolitan industrial challenge, the SIPNs may provide a useful reference for marine antifouling and some other relevant fields.

Review of Network Topologies and Protection Principles in Marine and Offshore Applications

DEFF Research Database (Denmark)

Ciontea, Catalin-Iosif; Bak, Claus Leth; Blaabjerg, Frede

2015-01-01

An electric fault that is not cleared is harmful in land applications, but in marine and offshore sector it can have catastrophic consequences. If the protection system fails to operate properly, the following situation may occur: blackouts, fire, loss of propulsion, delays in transportation......, collision with the cliff, reef or other ships and electrical shocks to humans. In order to cope with the unwanted effects of a fault, several protection strategies are applied, but complexity of the marine and offshore applications is continuously increasing, so protection needs to overcome more and more...... challenges. As result, development of new protection techniques that can offer improved functionalities compared to the actual solutions for marine and offshore applications is needed. This paper reviews the network topologies in such applications and presents the requirements of a system able to protect...

Adaptive comanagement of a marine protected area network in Fiji.

Science.gov (United States)

Weeks, Rebecca; Jupiter, Stacy D

2013-12-01

Adaptive management of natural resources is an iterative process of decision making whereby management strategies are progressively changed or adjusted in response to new information. Despite an increasing focus on the need for adaptive conservation strategies, there remain few applied examples. We describe the 9-year process of adaptive comanagement of a marine protected area network in Kubulau District, Fiji. In 2011, a review of protected area boundaries and management rules was motivated by the need to enhance management effectiveness and the desire to improve resilience to climate change. Through a series of consultations, with the Wildlife Conservation Society providing scientific input to community decision making, the network of marine protected areas was reconfigured so as to maximize resilience and compliance. Factors identified as contributing to this outcome include well-defined resource-access rights; community respect for a flexible system of customary governance; long-term commitment and presence of comanagement partners; supportive policy environment for comanagement; synthesis of traditional management approaches with systematic monitoring; and district-wide coordination, which provided a broader spatial context for adaptive-management decision making. Co-Manejo Adaptativo de una Red de Áreas Marinas Protegidas en Fiyi. © 2013 The Authors. Conservation Biology published by Wiley Periodicals, Inc., on behalf of the Society for Conservation Biology.

Real-time monitoring of enzyme-free strand displacement cascades by colorimetric assays

Science.gov (United States)

Duan, Ruixue; Wang, Boya; Hong, Fan; Zhang, Tianchi; Jia, Yongmei; Huang, Jiayu; Hakeem, Abdul; Liu, Nannan; Lou, Xiaoding; Xia, Fan

2015-03-01

The enzyme-free toehold-mediated strand displacement reaction has shown potential for building programmable DNA circuits, biosensors, molecular machines and chemical reaction networks. Here we report a simple colorimetric method using gold nanoparticles as signal generators for the real-time detection of the product of the strand displacement cascade. During the process the assembled gold nanoparticles can be separated, resulting in a color change of the solution. This assay can also be applied in complex mixtures, fetal bovine serum, and to detect single-base mismatches. These results suggest that this method could be of general utility to monitor more complex enzyme-free strand displacement reaction-based programmable systems or for further low-cost diagnostic applications.The enzyme-free toehold-mediated strand displacement reaction has shown potential for building programmable DNA circuits, biosensors, molecular machines and chemical reaction networks. Here we report a simple colorimetric method using gold nanoparticles as signal generators for the real-time detection of the product of the strand displacement cascade. During the process the assembled gold nanoparticles can be separated, resulting in a color change of the solution. This assay can also be applied in complex mixtures, fetal bovine serum, and to detect single-base mismatches. These results suggest that this method could be of general utility to monitor more complex enzyme-free strand displacement reaction-based programmable systems or for further low-cost diagnostic applications. Electronic supplementary information (ESI) available: Experimental procedures and analytical data are provided. See DOI: 10.1039/c5nr00697j

Assessment of the impact of xenobiotic pollutants on the marine organisms: Molecular biomarker approach

Digital Repository Service at National Institute of Oceanography (India)

Sarkar, A.

of the organisms to xenobiotic compounds being transformed into reactive oxygen species. Most importantly, the occurrence of DNA strand breaks in marine organisms leading to the loss of DNA integrity is a significant biomarker of marine pollution. The measurement...

Visualising Actor Network for Cooperative Systems in Marine Technology

DEFF Research Database (Denmark)

Pan, Yushan; Finken, Sisse

2016-01-01

Awareness is a concept familiar to specialists within the field of Computer Supported Cooperative Work (CSCW). It is superior for analysing and describing some of the ad hoc work activities that unfold in cooperation. Such informal activities are outside the scope of engineers’ formal models, whi...... that shape computer systems. The aim, thus, is to portray cooperative work in a way that can be valuable for engineers implementing marine technology. We do so by way of presenting a transferring technique (2T) using insights from the CSCW field and Actor Network Theory (ANT)....

Sub-Ensemble Monitoring of DNA Strand Displacement Using Multiparameter Single-Molecule FRET.

Science.gov (United States)

Baltierra-Jasso, Laura E; Morten, Michael J; Magennis, Steven W

2018-03-05

Non-enzymatic DNA strand displacement is an important mechanism in dynamic DNA nanotechnology. Here, we show that the large parameter space that is accessible by single-molecule FRET is ideal for the simultaneous monitoring of multiple reactants and products of DNA strand exchange reactions. We monitored the strand displacement from double-stranded DNA (dsDNA) by single-stranded DNA (ssDNA) at 37 °C; the data were modelled as a second-order reaction approaching equilibrium, with a rate constant of 10 m -1  s -1 . We also followed the displacement from a DNA three-way junction (3WJ) by ssDNA. The presence of three internal mismatched bases in the middle of the invading strand did not prevent displacement from the 3WJ, but reduced the second-order rate constant by about 50 %. We attribute strand exchange in the dsDNA and 3WJ to a zero-toehold pathway from the blunt-ended duplex arms. The single-molecule approach demonstrated here will be useful for studying complex DNA networks. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Risk Analysis Reveals Global Hotspots for Marine Debris Ingestion by Sea Turtles

Science.gov (United States)

Schuyler, Q. A.; Wilcox, C.; Townsend, K.; Wedemeyer-Strombel, K.; Balazs, G.; van Sebille, E.; Hardesty, B. D.

2016-02-01

Plastic marine debris pollution is rapidly becoming one of the critical environmental concerns facing wildlife in the 21st century. Here we present a risk analysis for plastic ingestion by sea turtles on a global scale. We combined global marine plastic distributions based on ocean drifter data with sea turtle habitat maps to predict exposure levels to plastic pollution. Empirical data from necropsies of deceased animals were then utilised to assess the consequence of exposure to plastics. We modelled the risk (probability of debris ingestion) by incorporating exposure to debris and consequence of exposure, and included life history stage, species of sea turtle, and date of stranding observation as possible additional explanatory factors. Life history stage is the best predictor of debris ingestion, but the best-fit model also incorporates encounter rates within a limited distance from stranding location, marine debris predictions specific to the date of the stranding study, and turtle species. There was no difference in ingestion rates between stranded turtles vs. those caught as bycatch from fishing activity, suggesting that stranded animals are not a biased representation of debris ingestion rates in the background population. Oceanic life-stage sea turtles are at the highest risk of debris ingestion, and olive ridley turtles are the most at-risk species. The regions of highest risk to global sea turtle populations are off of the east coasts of the USA, Australia, and South Africa; the east Indian Ocean, and Southeast Asia. Model results can be used to predict the number of sea turtles globally at risk of debris ingestion. Based on currently available data, initial calculations indicate that up to 52% of sea turtles may have ingested debris.

MaNIDA: Insight into the German Marine Network for Integrated Data Access

Science.gov (United States)

Schäfer, Angela; Scientific MaNIDA Team

2013-04-01

The Marine Network for Integrated Data Access (MaNIDA) builds a sustainable e-Infrastructure to support discovery and re-use of data from distinct marine and earth science data providers in Germany (see ESSI1.2 and ESSI2.2). Thereby we implement the "Data Portal of German Marine Research" for coherent discovery, view, download and dissemination of aggregated content. MaNIDA receives a unique momentum from the cooperation and financial partnership between main German marine research institutes (AWI, MARUM, HZG, GEOMAR, Uni Hamburg, Uni Kiel, Uni Bremen) and the Federal Maritime and Hydrographic Agency as well as active participation in international and major EU-initiatives (ICSU, GEOSS, SeaDataNet, EMODNET, ODIP). Together with a coherent management strategy coordinated by the Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research, sustainability will be achieved via the long-term commitment of framework funding by the Helmholtz Association, Germany's largest scientific research organization for large-scale facilities and scientific infrastructure. Strategic Aims The installation of the "Data Portal of German Marine Research" will address the urgent demands of the German research community for reliable and easy access to marine research data at one single point of access and truth. Primary focus will be given to data derived from nationally operated research and monitoring facilities (vessels, observatories, alert systems, etc), whereby related contextual content and publications will become an integral part of the aggregation effort. For the scientific community we define responsibilities and commitments across partners while complementing existing data repositories and the new portal with well-articulated workflows from the instrument to the data product. Necessary level of quality assurance and user support will be implemented to achieve substantial enhancements in the whole lifecycle management of marine scientific data. The creation of a data

Ruggedized Portable Instrumentation Package for Marine Mammal Evoked Potential Hearing Measurements (DURIP)

Science.gov (United States)

2011-09-30

NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Hawaii Institute of Marine Biology,Marine Mammal...Program Hawaii Institute of Marine Biology P.O. Box 1106 Kailua, Hawaii 96734 phone: (808) 247-5297 fax: (808) 247-5831 email: nachtiga...portable equipment was used at the Hilo Stranding Center to obtain the audiograms. Ready and available for RIMPAC excercises. 2 IMPACT

A common bottlenose dolphin (Tursiops truncatus) prey handling technique for marine catfish (Ariidae) in the northern Gulf of Mexico.

Science.gov (United States)

Ronje, Errol I; Barry, Kevin P; Sinclair, Carrie; Grace, Mark A; Barros, Nélio; Allen, Jason; Balmer, Brian; Panike, Anna; Toms, Christina; Mullin, Keith D; Wells, Randall S

2017-01-01

Few accounts describe predator-prey interactions between common bottlenose dolphins (Tursiops truncatus Montagu 1821) and marine catfish (Ariopsis felis Linnaeus 1766, Bagre marinus Mitchill 1815). Over the course of 50,167 sightings of bottlenose dolphin groups in Mississippi Sound and along the Florida coast of the Gulf of Mexico, severed catfish heads were found floating and exhibiting movements at the surface in close proximity to 13 dolphin groups that demonstrated feeding behavior. These observations prompted a multi-disciplinary approach to study the predator-prey relationship between bottlenose dolphins and marine catfish. A review was conducted of bottlenose dolphin visual survey data and dorsal fin photographs from sightings where severed catfish heads were observed. Recovered severed catfish heads were preserved and studied, whole marine catfish were collected and examined, and stranding network pathology reports were reviewed for references to injuries related to fish spines. Photographic identification analysis confirms eight dolphins associated with severed catfish heads were present in three such sightings across an approximately 350 km expanse of coast between the Mississippi Sound and Saint Joseph Bay, FL. An examination of the severed catfish heads indicated interaction with dolphins, and fresh-caught whole hardhead catfish (A. felis) were examined to estimate the presumed total length of the catfish before decapitation. Thirty-eight instances of significant trauma or death in dolphins attributed to ingesting whole marine catfish were documented in stranding records collected from the southeastern United States of America. Bottlenose dolphins typically adhere to a ram-feeding strategy for prey capture followed by whole prey ingestion; however, marine catfish skull morphology may pose a consumption hazard due to rigid spines that can puncture and migrate through soft tissue, prompting a prey handling technique for certain dolphins, facilitating

77 FR 43238 - Takes of Marine Mammals Incidental to Specified Activities; Navy Training Conducted at the Silver...

Science.gov (United States)

2012-07-24

... which case the animal's hearing threshold will recover over time (Southall et al. 2007). Since marine... et al. 2002). However, in order for marine mammals to experience TTS or PTS, the animals have to be... Marine Mammals Incidental to Specified Activities; Navy Training Conducted at the Silver Strand Training...

Indications of marine bioinvasion from network theory. An analysis of the global cargo ship network

Science.gov (United States)

Kölzsch, A.; Blasius, B.

2011-12-01

The transport of huge amounts of small aquatic organisms in the ballast tanks and at the hull of large cargo ships leads to ever increasing rates of marine bioinvasion. In this study, we apply a network theoretic approach to examine the introduction of invasive species into new ports by global shipping. This is the first stage of the invasion process where it is still possible to intervene with regulating measures. We compile a selection of widely used and newly developed network properties and apply these to analyse the structure and spread characteristics of the directed and weighted global cargo ship network (GCSN). Our results reveal that the GCSN is highly efficient, shows small world characteristics and is positive assortative, indicating that quick spread of invasive organisms between ports is likely. The GCSN shows strong community structure and contains two large communities, the Atlantic and Pacific trading groups. Ports that appear as connector hubs and are of high centralities are the Suez and Panama Canal, Singapore and Shanghai. Furthermore, from robustness analyses and the network's percolation behaviour, we evaluate differences of onboard and in-port ballast water treatment, set them into context with previous studies and advise bioinvasion management strategies.

Brain Meta-Transcriptomics from Harbor Seals to Infer the Role of the Microbiome and Virome in a Stranding Event.

Science.gov (United States)

Rosales, Stephanie M; Thurber, Rebecca Vega

2015-01-01

Marine diseases are becoming more frequent, and tools for identifying pathogens and disease reservoirs are needed to help prevent and mitigate epizootics. Meta-transcriptomics provides insights into disease etiology by cataloguing and comparing sequences from suspected pathogens. This method is a powerful approach to simultaneously evaluate both the viral and bacterial communities, but few studies have applied this technique in marine systems. In 2009 seven harbor seals, Phoca vitulina, stranded along the California coast from a similar brain disease of unknown cause of death (UCD). We evaluated the differences between the virome and microbiome of UCDs and harbor seals with known causes of death. Here we determined that UCD stranded animals had no viruses in their brain tissue. However, in the bacterial community, we identified Burkholderia and Coxiella burnetii as important pathogens associated with this stranding event. Burkholderia were 100% prevalent and ~2.8 log2 fold more abundant in the UCD animals. Further, while C. burnetii was found in only 35.7% of all samples, it was highly abundant (~94% of the total microbial community) in a single individual. In this harbor seal, C. burnetii showed high transcription rates of invading and translation genes, implicating it in the pathogenesis of this animal. Based on these data we propose that Burkholderia taxa and C. burnetii are potentially important opportunistic neurotropic pathogens in UCD stranded harbor seals.

Brain Meta-Transcriptomics from Harbor Seals to Infer the Role of the Microbiome and Virome in a Stranding Event.

Directory of Open Access Journals (Sweden)

Stephanie M Rosales

Full Text Available Marine diseases are becoming more frequent, and tools for identifying pathogens and disease reservoirs are needed to help prevent and mitigate epizootics. Meta-transcriptomics provides insights into disease etiology by cataloguing and comparing sequences from suspected pathogens. This method is a powerful approach to simultaneously evaluate both the viral and bacterial communities, but few studies have applied this technique in marine systems. In 2009 seven harbor seals, Phoca vitulina, stranded along the California coast from a similar brain disease of unknown cause of death (UCD. We evaluated the differences between the virome and microbiome of UCDs and harbor seals with known causes of death. Here we determined that UCD stranded animals had no viruses in their brain tissue. However, in the bacterial community, we identified Burkholderia and Coxiella burnetii as important pathogens associated with this stranding event. Burkholderia were 100% prevalent and ~2.8 log2 fold more abundant in the UCD animals. Further, while C. burnetii was found in only 35.7% of all samples, it was highly abundant (~94% of the total microbial community in a single individual. In this harbor seal, C. burnetii showed high transcription rates of invading and translation genes, implicating it in the pathogenesis of this animal. Based on these data we propose that Burkholderia taxa and C. burnetii are potentially important opportunistic neurotropic pathogens in UCD stranded harbor seals.

Sensitivity of marine protected area network connectivity to atmospheric variability.

Science.gov (United States)

Fox, Alan D; Henry, Lea-Anne; Corne, David W; Roberts, J Murray

2016-11-01

International efforts are underway to establish well-connected systems of marine protected areas (MPAs) covering at least 10% of the ocean by 2020. But the nature and dynamics of ocean ecosystem connectivity are poorly understood, with unresolved effects of climate variability. We used 40-year runs of a particle tracking model to examine the sensitivity of an MPA network for habitat-forming cold-water corals in the northeast Atlantic to changes in larval dispersal driven by atmospheric cycles and larval behaviour. Trajectories of Lophelia pertusa larvae were strongly correlated to the North Atlantic Oscillation (NAO), the dominant pattern of interannual atmospheric circulation variability over the northeast Atlantic. Variability in trajectories significantly altered network connectivity and source-sink dynamics, with positive phase NAO conditions producing a well-connected but asymmetrical network connected from west to east. Negative phase NAO produced reduced connectivity, but notably some larvae tracked westward-flowing currents towards coral populations on the mid-Atlantic ridge. Graph theoretical metrics demonstrate critical roles played by seamounts and offshore banks in larval supply and maintaining connectivity across the network. Larval longevity and behaviour mediated dispersal and connectivity, with shorter lived and passive larvae associated with reduced connectivity. We conclude that the existing MPA network is vulnerable to atmospheric-driven changes in ocean circulation.

The stranding anomaly as population indicator: the case of Harbour Porpoise

NARCIS (Netherlands)

Peltier, H.; Baagøe, H.J.; Camphuysen, K.C.J.; Czeck, R.; Dabin, W.; Daniel, P.; Deaville, R.; Haelters, J.; Jauniaux, T.; Jensen, L.F.; Jepson, P.D.; Keijl, G.O.; Siebert, U.; Van Canneyt, O.; Ridoux, V.

2013-01-01

Ecological indicators for monitoring strategies are expected to combine three major characteristics: ecological significance, statistical credibility, and cost-effectiveness. Strategies based on stranding networks rank highly in cost-effectiveness, but their ecological significance and statistical

Risk analysis reveals global hotspots for marine debris ingestion by sea turtles.

Science.gov (United States)

Schuyler, Qamar A; Wilcox, Chris; Townsend, Kathy A; Wedemeyer-Strombel, Kathryn R; Balazs, George; van Sebille, Erik; Hardesty, Britta Denise

2016-02-01

Plastic marine debris pollution is rapidly becoming one of the critical environmental concerns facing wildlife in the 21st century. Here we present a risk analysis for plastic ingestion by sea turtles on a global scale. We combined global marine plastic distributions based on ocean drifter data with sea turtle habitat maps to predict exposure levels to plastic pollution. Empirical data from necropsies of deceased animals were then utilised to assess the consequence of exposure to plastics. We modelled the risk (probability of debris ingestion) by incorporating exposure to debris and consequence of exposure, and included life history stage, species of sea turtle and date of stranding observation as possible additional explanatory factors. Life history stage is the best predictor of debris ingestion, but the best-fit model also incorporates encounter rates within a limited distance from stranding location, marine debris predictions specific to the date of the stranding study and turtle species. There is no difference in ingestion rates between stranded turtles vs. those caught as bycatch from fishing activity, suggesting that stranded animals are not a biased representation of debris ingestion rates in the background population. Oceanic life-stage sea turtles are at the highest risk of debris ingestion, and olive ridley turtles are the most at-risk species. The regions of highest risk to global sea turtle populations are off of the east coasts of the USA, Australia and South Africa; the east Indian Ocean, and Southeast Asia. Model results can be used to predict the number of sea turtles globally at risk of debris ingestion. Based on currently available data, initial calculations indicate that up to 52% of sea turtles may have ingested debris. © 2015 John Wiley & Sons Ltd.

Active Marine Station Metadata

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Active Marine Station Metadata is a daily metadata report for active marine bouy and C-MAN (Coastal Marine Automated Network) platforms from the National Data...

Unmanned Aerial Vehicle Based Wireless Sensor Network for Marine-Coastal Environment Monitoring.

Science.gov (United States)

Trasviña-Moreno, Carlos A; Blasco, Rubén; Marco, Álvaro; Casas, Roberto; Trasviña-Castro, Armando

2017-02-24

Marine environments are delicate ecosystems which directly influence local climates, flora, fauna, and human activities. Their monitorization plays a key role in their preservation, which is most commonly done through the use of environmental sensing buoy networks. These devices transmit data by means of satellite communications or close-range base stations, which present several limitations and elevated infrastructure costs. Unmanned Aerial Vehicles (UAV) are another alternative for remote environmental monitoring which provide new types of data and ease of use. These aircraft are mainly used in video capture related applications, in its various light spectrums, and do not provide the same data as sensing buoys, nor can they be used for such extended periods of time. The aim of this research is to provide a flexible, easy to deploy and cost-effective Wireless Sensor Network (WSN) for monitoring marine environments. This proposal uses a UAV as a mobile data collector, low-power long-range communications and sensing buoys as part of a single WSN. A complete description of the design, development, and implementation of the various parts of this system is presented, as well as its validation in a real-world scenario.

A host-endoparasite network of Neotropical marine fish: are there organizational patterns?

Science.gov (United States)

Bellay, Sybelle; Lima, Dilermando P; Takemoto, Ricardo M; Luque, José L

2011-12-01

Properties of ecological networks facilitate the understanding of interaction patterns in host-parasite systems as well as the importance of each species in the interaction structure of a community. The present study evaluates the network structure, functional role of all species and patterns of parasite co-occurrence in a host-parasite network to determine the organization level of a host-parasite system consisting of 170 taxa of gastrointestinal metazoans of 39 marine fish species on the coast of Brazil. The network proved to be nested and modular, with a low degree of connectance. Host-parasite interactions were influenced by host phylogeny. Randomness in parasite co-occurrence was observed in most modules and component communities, although species segregation patterns were also observed. The low degree of connectance in the network may be the cause of properties such as nestedness and modularity, which indicate the presence of a high number of peripheral species. Segregation patterns among parasite species in modules underscore the role of host specificity. Knowledge of ecological networks allows detection of keystone species for the maintenance of biodiversity and the conduction of further studies on the stability of networks in relation to frequent environmental changes.

Assessment of habitat representation across a network of marine protected areas with implications for the spatial design of monitoring.

Science.gov (United States)

Young, Mary; Carr, Mark

2015-01-01

Networks of marine protected areas (MPAs) are being adopted globally to protect ecosystems and supplement fisheries management. The state of California recently implemented a coast-wide network of MPAs, a statewide seafloor mapping program, and ecological characterizations of species and ecosystems targeted for protection by the network. The main goals of this study were to use these data to evaluate how well seafloor features, as proxies for habitats, are represented and replicated across an MPA network and how well ecological surveys representatively sampled fish habitats inside MPAs and adjacent reference sites. Seafloor data were classified into broad substrate categories (rock and sediment) and finer scale geomorphic classifications standard to marine classification schemes using surface analyses (slope, ruggedness, etc.) done on the digital elevation model derived from multibeam bathymetry data. These classifications were then used to evaluate the representation and replication of seafloor structure within the MPAs and across the ecological surveys. Both the broad substrate categories and the finer scale geomorphic features were proportionately represented for many of the classes with deviations of 1-6% and 0-7%, respectively. Within MPAs, however, representation of seafloor features differed markedly from original estimates, with differences ranging up to 28%. Seafloor structure in the biological monitoring design had mismatches between sampling in the MPAs and their corresponding reference sites and some seafloor structure classes were missed entirely. The geomorphic variables derived from multibeam bathymetry data for these analyses are known determinants of the distribution and abundance of marine species and for coastal marine biodiversity. Thus, analyses like those performed in this study can be a valuable initial method of evaluating and predicting the conservation value of MPAs across a regional network.

The ISMAR high frequency coastal radar network: Monitoring surface currents for management of marine resources

DEFF Research Database (Denmark)

Carlson, Daniel Frazier

2015-01-01

The Institute of Marine Sciences (ISMAR) of the National Research Council of Italy (CNR) established a High Frequency (HF) Coastal Radar Network for the measurement of the velocity of surface currents in coastal seas. The network consists of four HF radar systems located on the coast of the Gargano...... Promontory (Southern Adriatic, Italy). The network has been operational since May 2013 and covers an area of approximately 1700 square kilometers in the Gulf of Manfredonia. Quality Assessment (QA) procedures are applied for the systems deployment and maintenance and Quality Control (QC) procedures...

Towards a network of locally managed marine areas (LMMAs in the Western Indian Ocean.

Directory of Open Access Journals (Sweden)

Steve Rocliffe

Full Text Available In the Western Indian Ocean (WIO, local communities are increasingly assuming responsibility for inshore marine resources either on their own or through collaborative management arrangements with governments or non-state actors. In this paper, we trace the evolution and expansion of community management in the WIO and present the first ever inventory and assessment of the region's locally managed marine areas (LMMAs. We compare the key attributes of these areas to those under government stewardship and assess their relative contributions to progress towards the Convention on Biodiversity (CBD target of 10% of marine and coastal ecological regions to be effectively conserved by 2020. We also explore the legal frameworks that underpin locally managed marine initiatives in Kenya, Madagascar, Mozambique and Tanzania to assess the potential for future expansion. A principal finding is that whilst LMMAs protect more than 11,000 square kilometres of marine resource in the WIO, they are hampered by underdeveloped local and national legal structures and enforcement mechanisms. In our recommendations to improve local management, we suggest establishing a network of LMMA practitioners in the WIO region to share experiences and best practice.

Postmortem evidence of interactions of bottlenose dolphins (Tursiops truncatus) with other dolphin species in south-west England.

Science.gov (United States)

Barnett, J; Davison, N; Deaville, R; Monies, R; Loveridge, J; Tregenza, N; Jepson, P D

2009-10-10

Reports of violent interactions between bottlenose dolphins (Tursiops truncatus) and harbour porpoises (Phocoena phocoena) in the coastal waters of the UK are well documented. Examination of stranded cetaceans by the Cornwall Wildlife Trust Marine Strandings Network and the UK Cetacean Strandings Investigation Programme has indicated that seven animals, of four other species, found stranded in south-west England, had pathology consistent with bottlenose dolphin interaction, including two juvenile and two adult common dolphins (Delphinus delphis), one juvenile pilot whale (Globicephala melas), one juvenile Risso's dolphin (Grampus griseus) and one adult striped dolphin (Stenella coeruleoalba). Although recorded traumatic lesions were often not as severe as those found in harbour porpoises, it is probable that the interactions did contribute to stranding and/or death in all four of the juvenile animals examined. Furthermore, analysis of photographs taken before establishment of the Marine Strandings Network revealed rake (teeth) marks consistent with bottlenose dolphin interaction on one stranded common dolphin in 1992. A number of causes have been suggested for these interactions in harbour porpoises stranded in the UK and it is possible that any combination of these factors may also be implicated in the cases described in this report.

Australia’s protected area network fails to adequately protect the world’s most threatened marine fishes

Directory of Open Access Journals (Sweden)

Karen R. Devitt

2015-01-01

Full Text Available In order to maintain ecosystems and biodiversity, Australia has long invested in the development of marine and terrestrial protected area networks. Within this land- and sea-scape, northern Australia represents a global population stronghold for four species of the world’s most threatened marine fish family, the sawfishes (family Pristidae. The distribution of sawfishes across northern Australia has previously only been coarsely estimated, and the adequacy of their representation in protected areas has not been evaluated. The calculated range of each species was intersected with Australia’s marine and terrestrial protected area datasets, and targets of 10% marine and 17% inland range protection were used to determine adequacy of sawfish range protection. Marine targets have been achieved for all species, but the inland range protection targets have not been met for any species. Results indicate that further protection of inland habitats is required in order to improve sawfish protection and habitat connectivity.

Mechanical properties of rubberwood oriented strand lumber (OSL: The effect of strand length

Directory of Open Access Journals (Sweden)

Buhnnum Kyokong

2005-09-01

Full Text Available Effect of strand length on mechanical properties (tension, compression and bending of oriented strand lumber (OSL made of rubberwood (Hevea brasiliensis Muell. Arg. was reported. Three strand lengths of 50 mm, 100 mm, and 150 mm with 1 mm thickness and 15 mm width were used. The strands were mixed with 5% pMDI glue (weight basis in a tumble mixer. The OSL specimens were formed by hot pressing process of unidirectionally aligned strands. Average specific gravity and moisture content were 0.76 and 8.34%, respectively. Tension and compression tests were carried out for directions both parallel and perpendicular to grain while bending test was performed only in parallel direction. Ultimate stresses and moduli of elasticity were examined from the stress-strain curves. It was found that for the parallel-to-grain direction, the longer strand OSL gave higher strength. The role of the strand length did not appear for the direction normal to the grain. The relationship between the mechanical properties of OSL and strand length was well described by the modified Hankinson formula.

Possible causes of a harbour porpoise mass stranding in Danish waters in 2005.

Directory of Open Access Journals (Sweden)

Andrew J Wright

Full Text Available An unprecedented 85 harbour porpoises stranded freshly dead along approximately 100 km of Danish coastline from 7-15 April, 2005. This total is considerably above the mean weekly stranding rate for the whole of Denmark, both for any time of year, 1.23 animals/week (ranging from 0 to 20 during 2003-2008, excluding April 2005, and specifically in April, 0.65 animals/week (0 to 4, same period. Bycatch was established as the cause of death for most of the individuals through typical indications of fisheries interactions, including net markings in the skin and around the flippers, and loss of tail flukes. Local fishermen confirmed unusually large porpoise bycatch in nets set for lumpfish (Cyclopterus lumpus and the strandings were attributed to an early lumpfish season. However, lumpfish catches for 2005 were not unusual in terms of season onset, peak or total catch, when compared to 2003-2008. Consequently, human activity was combined with environmental factors and the variation in Danish fisheries landings (determined through a principal component analysis in a two-part statistical model to assess the correlation of these factors with both the presence of fresh strandings and the numbers of strandings on the Danish west coast. The final statistical model (which was forward selected using Akaike information criterion; AIC indicated that naval presence is correlated with higher rates of porpoise strandings, particularly in combination with certain fisheries, although it is not correlated with the actual presence of strandings. Military vessels from various countries were confirmed in the area from the 7th April, en route to the largest naval exercise in Danish waters to date (Loyal Mariner 2005, 11-28 April. Although sonar usage cannot be confirmed, it is likely that ships were testing various equipment prior to the main exercise. Thus naval activity cannot be ruled out as a possible contributing factor.

Intelligent Image Recognition System for Marine Fouling Using Softmax Transfer Learning and Deep Convolutional Neural Networks

Directory of Open Access Journals (Sweden)

C. S. Chin

2017-01-01

Full Text Available The control of biofouling on marine vessels is challenging and costly. Early detection before hull performance is significantly affected is desirable, especially if “grooming” is an option. Here, a system is described to detect marine fouling at an early stage of development. In this study, an image of fouling can be transferred wirelessly via a mobile network for analysis. The proposed system utilizes transfer learning and deep convolutional neural network (CNN to perform image recognition on the fouling image by classifying the detected fouling species and the density of fouling on the surface. Transfer learning using Google’s Inception V3 model with Softmax at last layer was carried out on a fouling database of 10 categories and 1825 images. Experimental results gave acceptable accuracies for fouling detection and recognition.

Reef-fish larval dispersal patterns validate no-take marine reserve network connectivity that links human communities

KAUST Repository

Abesamis, Rene A.; Saenz-Agudelo, Pablo; Berumen, Michael L.; Bode, Michael; Jadloc, Claro Renato L.; Solera, Leilani A.; Villanoy, Cesar L.; Bernardo, Lawrence Patrick C.; Alcala, Angel C.; Russ, Garry R.

2017-01-01

Networks of no-take marine reserves (NTMRs) are a widely advocated strategy for managing coral reefs. However, uncertainty about the strength of population connectivity between individual reefs and NTMRs through larval dispersal remains a major

Assessment of habitat representation across a network of marine protected areas with implications for the spatial design of monitoring.

Directory of Open Access Journals (Sweden)

Mary Young

Full Text Available Networks of marine protected areas (MPAs are being adopted globally to protect ecosystems and supplement fisheries management. The state of California recently implemented a coast-wide network of MPAs, a statewide seafloor mapping program, and ecological characterizations of species and ecosystems targeted for protection by the network. The main goals of this study were to use these data to evaluate how well seafloor features, as proxies for habitats, are represented and replicated across an MPA network and how well ecological surveys representatively sampled fish habitats inside MPAs and adjacent reference sites. Seafloor data were classified into broad substrate categories (rock and sediment and finer scale geomorphic classifications standard to marine classification schemes using surface analyses (slope, ruggedness, etc. done on the digital elevation model derived from multibeam bathymetry data. These classifications were then used to evaluate the representation and replication of seafloor structure within the MPAs and across the ecological surveys. Both the broad substrate categories and the finer scale geomorphic features were proportionately represented for many of the classes with deviations of 1-6% and 0-7%, respectively. Within MPAs, however, representation of seafloor features differed markedly from original estimates, with differences ranging up to 28%. Seafloor structure in the biological monitoring design had mismatches between sampling in the MPAs and their corresponding reference sites and some seafloor structure classes were missed entirely. The geomorphic variables derived from multibeam bathymetry data for these analyses are known determinants of the distribution and abundance of marine species and for coastal marine biodiversity. Thus, analyses like those performed in this study can be a valuable initial method of evaluating and predicting the conservation value of MPAs across a regional network.

Application of ecological criteria in selecting marine reserves and developing reserve networks

Science.gov (United States)

Roberts, Callum M.; Branch, George; Bustamante, Rodrigo H.; Castilla, Juan Carlos; Dugan, Jenifer; Halpern, Benjamin S.; Lafferty, Kevin D.; Leslie, Heather; McArdle, Deborah; Ruckelshaus, Mary; Warner, Robert R.

2003-01-01

Marine reserves are being established worldwide in response to a growing recognition of the conservation crisis that is building in the oceans. However, designation of reserves has been largely opportunistic, or protective measures have been implemented (often overlapping and sometimes in conflict) by different entities seeking to achieve different ends. This has created confusion among both users and enforcers, and the proliferation of different measures provides a false sense of protection where little is offered. This paper sets out a procedure grounded in current understanding of ecological processes, that allows the evaluation and selection of reserve sites in order to develop functional, interconnected networks of fully protected reserves that will fulfill multiple objectives. By fully protected we mean permanently closed to fishing and other resource extraction. We provide a framework that unifies the central aims of conservation and fishery management, while also meeting other human needs such as the provision of ecosystem services (e.g., maintenance of coastal water quality, shoreline protection, and recreational opportunities). In our scheme, candidate sites for reserves are evaluated against 12 criteria focused toward sustaining the biological integrity and productivity of marine systems at both local and regional scales. While a limited number of sites will be indispensable in a network, many will be of similar value as reserves, allowing the design of numerous alternative, biologically adequate networks. Devising multiple network designs will help ensure that ecological functionality is preserved throughout the socioeconomic evaluation process. Too often, socioeconomic criteria have dominated the process of reserve selection, potentially undermining their efficacy. We argue that application of biological criteria must precede and inform socioeconomic evaluation, since maintenance of ecosystem functioning is essential for meeting all of the goals for

The Moves of a Bajau Middlewomen: Understanding the Disparity between Trade Networks and Marine Conservation.

NARCIS (Netherlands)

Pauwelussen, A.P.

2015-01-01

At the interface of Indonesia and Malaysia, border-crossing maritime trade appears to elude attempts to conserve marine resources. In Berau district (East Kalimantan) attempts to protect coastal waters from illegal fishing and trade fail to correspond with mobile trade networks. In this article, I

FINAL TECHNICAL REPORT: Underwater Active Acoustic Monitoring Network For Marine And Hydrokinetic Energy Projects

Energy Technology Data Exchange (ETDEWEB)

Stein, Peter J. [Scientific Solutions, Inc, Nashua, NH (United States); Edson, Patrick L. [Scientific Solutions, Inc, Nashua, NH (United States)

2013-12-20

This project saw the completion of the design and development of a second generation, high frequency (90-120 kHz) Subsurface-Threat Detection Sonar Network (SDSN). The system was deployed, operated, and tested in Cobscook Bay, Maine near the site the Ocean Renewable Power Company TidGen™ power unit. This effort resulted in a very successful demonstration of the SDSN detection, tracking, localization, and classification capabilities in a high current, MHK environment as measured by results from the detection and tracking trials in Cobscook Bay. The new high frequency node, designed to operate outside the hearing range of a subset of marine mammals, was shown to detect and track objects of marine mammal-like target strength to ranges of approximately 500 meters. This performance range results in the SDSN system tracking objects for a significant duration - on the order of minutes - even in a tidal flow of 5-7 knots, potentially allowing time for MHK system or operator decision-making if marine mammals are present. Having demonstrated detection and tracking of synthetic targets with target strengths similar to some marine mammals, the primary hurdle to eventual automated monitoring is a dataset of actual marine mammal kinematic behavior and modifying the tracking algorithms and parameters which are currently tuned to human diver kinematics and classification.

No Reef Is an Island: Integrating Coral Reef Connectivity Data into the Design of Regional-Scale Marine Protected Area Networks.

Science.gov (United States)

Schill, Steven R; Raber, George T; Roberts, Jason J; Treml, Eric A; Brenner, Jorge; Halpin, Patrick N

2015-01-01

We integrated coral reef connectivity data for the Caribbean and Gulf of Mexico into a conservation decision-making framework for designing a regional scale marine protected area (MPA) network that provides insight into ecological and political contexts. We used an ocean circulation model and regional coral reef data to simulate eight spawning events from 2008-2011, applying a maximum 30-day pelagic larval duration and 20% mortality rate. Coral larval dispersal patterns were analyzed between coral reefs across jurisdictional marine zones to identify spatial relationships between larval sources and destinations within countries and territories across the region. We applied our results in Marxan, a conservation planning software tool, to identify a regional coral reef MPA network design that meets conservation goals, minimizes underlying threats, and maintains coral reef connectivity. Our results suggest that approximately 77% of coral reefs identified as having a high regional connectivity value are not included in the existing MPA network. This research is unique because we quantify and report coral larval connectivity data by marine ecoregions and Exclusive Economic Zones (EZZ) and use this information to identify gaps in the current Caribbean-wide MPA network by integrating asymmetric connectivity information in Marxan to design a regional MPA network that includes important reef network connections. The identification of important reef connectivity metrics guides the selection of priority conservation areas and supports resilience at the whole system level into the future.

No Reef Is an Island: Integrating Coral Reef Connectivity Data into the Design of Regional-Scale Marine Protected Area Networks.

Directory of Open Access Journals (Sweden)

Steven R Schill

Full Text Available We integrated coral reef connectivity data for the Caribbean and Gulf of Mexico into a conservation decision-making framework for designing a regional scale marine protected area (MPA network that provides insight into ecological and political contexts. We used an ocean circulation model and regional coral reef data to simulate eight spawning events from 2008-2011, applying a maximum 30-day pelagic larval duration and 20% mortality rate. Coral larval dispersal patterns were analyzed between coral reefs across jurisdictional marine zones to identify spatial relationships between larval sources and destinations within countries and territories across the region. We applied our results in Marxan, a conservation planning software tool, to identify a regional coral reef MPA network design that meets conservation goals, minimizes underlying threats, and maintains coral reef connectivity. Our results suggest that approximately 77% of coral reefs identified as having a high regional connectivity value are not included in the existing MPA network. This research is unique because we quantify and report coral larval connectivity data by marine ecoregions and Exclusive Economic Zones (EZZ and use this information to identify gaps in the current Caribbean-wide MPA network by integrating asymmetric connectivity information in Marxan to design a regional MPA network that includes important reef network connections. The identification of important reef connectivity metrics guides the selection of priority conservation areas and supports resilience at the whole system level into the future.

Using a neural network approach and time series data from an international monitoring station in the Yellow Sea for modeling marine ecosystems.

Science.gov (United States)

Zhang, Yingying; Wang, Juncheng; Vorontsov, A M; Hou, Guangli; Nikanorova, M N; Wang, Hongliang

2014-01-01

The international marine ecological safety monitoring demonstration station in the Yellow Sea was developed as a collaborative project between China and Russia. It is a nonprofit technical workstation designed as a facility for marine scientific research for public welfare. By undertaking long-term monitoring of the marine environment and automatic data collection, this station will provide valuable information for marine ecological protection and disaster prevention and reduction. The results of some initial research by scientists at the research station into predictive modeling of marine ecological environments and early warning are described in this paper. Marine ecological processes are influenced by many factors including hydrological and meteorological conditions, biological factors, and human activities. Consequently, it is very difficult to incorporate all these influences and their interactions in a deterministic or analysis model. A prediction model integrating a time series prediction approach with neural network nonlinear modeling is proposed for marine ecological parameters. The model explores the natural fluctuations in marine ecological parameters by learning from the latest observed data automatically, and then predicting future values of the parameter. The model is updated in a "rolling" fashion with new observed data from the monitoring station. Prediction experiments results showed that the neural network prediction model based on time series data is effective for marine ecological prediction and can be used for the development of early warning systems.

Lagrangian Flow Network: a new tool to evaluate connectivity and understand the structural complexity of marine populations

Science.gov (United States)

Rossi, V.; Dubois, M.; Ser-Giacomi, E.; Monroy, P.; Lopez, C.; Hernandez-Garcia, E.

2016-02-01

Assessing the spatial structure and dynamics of marine populations is still a major challenge for ecologists. The necessity to manage marine resources from a large-scale perspective and considering the whole ecosystem is now recognized but the absence of appropriate tools to address these objectives limits the implementation of globally pertinent conservation planning. Inspired from Network Theory, we present a new methodological framework called Lagrangian Flow Network which allows a systematic characterization of multi-scale dispersal and connectivity of early life history stages of marine organisms. The network is constructed by subdividing the basin into an ensemble of equal-area subregions which are interconnected through the transport of propagules by ocean currents. The present version allows the identification of hydrodynamical provinces and the computation of various connectivity proxies measuring retention and exchange of larvae. Due to our spatial discretization and subsequent network representation, as well as our Lagrangian approach, further methodological improvements are handily accessible. These future developments include a parametrization of habitat patchiness, the implementation of realistic larval traits and the consideration of abiotic variables (e.g. temperature, salinity, planktonic resources...) and their effects on larval production and survival. While the model is potentially tunable to any species whose biological traits and ecological preferences are precisely known, it can also be used in a more generic configuration by efficient computing and analysis of a large number of experiments with relevant ecological parameters. It permits a better characterization of population connectivity at multiple scales and it informs its ecological and managerial interpretations.

Stranded costs and exit fees

International Nuclear Information System (INIS)

2002-01-01

The New Brunswick Market Design Committee has been directed to examine the issue of stranded costs since it is a major component of restructuring within the electricity sector. When regulated monopolies are faced with competition, they could find that some of their embedded costs cannot be recovered. These costs are referred to as stranded costs. Common sources include large capital investments in uneconomic plants or expensive power purchase contracts or fuel supply contracts. In general, stranded costs do not include gains or losses associated with normal business risks experienced by regulated utilities. This report presents recommendations for mitigation of stranded costs, valuation methodologies and cost-recovery mechanisms. It also presents a summary of experience with stranded costs in other jurisdictions such as California, Rhode Island, Pennsylvania and Ontario. Stranded costs are often recovered through an obligatory charge on all customers, particularly in jurisdictions where retail competition exists. In the New Brunswick market, however, the only customers who can create stranded costs are those eligible to choose their own suppliers. It is argued that since most customers will not have a choice of electricity suppliers, they cannot generate stranded costs and therefore, should not have to pay costs stranded by others. A method to quantify stranded costs is presented, along with a review of transmission-related stranded costs in New Brunswick. Expansion of self-generation in New Brunswick could strand transmission assets. Currently, self-generators only contribute a small amount to fixed charges of the transmission system. However, under new recommended tariffs, the amount could increase. It is likely that the net amount of stranded transmission costs will not be large. 2 refs., 1 fig

Strand Displacement by DNA Polymerase III Occurs through a τ-ψ-χ Link to Single-stranded DNA-binding Protein Coating the Lagging Strand Template*

OpenAIRE

Yuan, Quan; McHenry, Charles S.

2009-01-01

In addition to the well characterized processive replication reaction catalyzed by the DNA polymerase III holoenzyme on single-stranded DNA templates, the enzyme possesses an intrinsic strand displacement activity on flapped templates. The strand displacement activity is distinguished from the single-stranded DNA-templated reaction by a high dependence upon single-stranded DNA binding protein and an inability of γ-complex to support the reaction in the absence of τ. However, if γ-complex is p...

Acoustic Response and Detection of Marine Mammals Using an Advanced Digital Acoustic Recording Tag(Rev 3)

Science.gov (United States)

2007-03-13

the SERDP program. With the reduced size and weight of the new tag as compared to the original design, less flotation was required resulting in a...Plenary Meeting of Marine Mammal Commission Federal Advisory Committee on Acoustic Impacts on Marine Mammals, Silver Spring Maryland, April 19-21...2002. Mass stranding of beaked whales in the Galapagos Islands, April 2000. National Marine Fisheries Service, Silver Spring. Harwood, J. 2000 Risk

ARCTOX: a pan-Arctic sampling network to track mercury contamination across Arctic marine food webs

DEFF Research Database (Denmark)

Fort, Jerome; Helgason, Halfdan; Amelineau, Francoise

and is still a source of major environmental concerns. In that context, providing a large-scale and comprehensive understanding of the Arctic marine food-web contamination is essential to better apprehend impacts of anthropogenic activities and climate change on the exposure of Arctic species and humans to Hg....... In 2015, an international sampling network (ARCTOX) has been established, allowing the collection seabird samples all around the Arctic. Seabirds are indeed good indicators of Hg contamination of marine food webs at large spatial scale. Gathering researchers from 10 countries, ARCTOX allowed......Arctic marine ecosystems are threatened by new risks of Hg contamination under the combined effects of climate change and human activities. Rapid change of the cryosphere might for instance release large amounts of Hg trapped in sea-ice, permafrost and terrestrial glaciers over the last decades...

Submarine canyons represent an essential habitat network for krill hotspots in a Large Marine Ecosystem.

Science.gov (United States)

Santora, Jarrod A; Zeno, Ramona; Dorman, Jeffrey G; Sydeman, William J

2018-05-15

Submarine canyon systems are ubiquitous features of marine ecosystems, known to support high levels of biodiversity. Canyons may be important to benthic-pelagic ecosystem coupling, but their role in concentrating plankton and structuring pelagic communities is not well known. We hypothesize that at the scale of a large marine ecosystem, canyons provide a critical habitat network, which maintain energy flow and trophic interactions. We evaluate canyon characteristics relative to the distribution and abundance of krill, critically important prey in the California Current Ecosystem. Using a geological database, we conducted a census of canyon locations, evaluated their dimensions, and quantified functional relationships with krill hotspots (i.e., sites of persistently elevated abundance) derived from hydro-acoustic surveys. We found that 76% of krill hotspots occurred within and adjacent to canyons. Most krill hotspots were associated with large shelf-incising canyons. Krill hotspots and canyon dimensions displayed similar coherence as a function of latitude and indicate a potential regional habitat network. The latitudinal migration of many fish, seabirds and mammals may be enhanced by using this canyon-krill network to maintain foraging opportunities. Biogeographic assessments and predictions of krill and krill-predator distributions under climate change may be improved by accounting for canyons in habitat models.

Fecal bacterial communities of wild-captured and stranded green turtles (Chelonia mydas) on the Great Barrier Reef.

Science.gov (United States)

Ahasan, Md Shamim; Waltzek, Thomas B; Huerlimann, Roger; Ariel, Ellen

2017-12-01

Green turtles (Chelonia mydas) are endangered marine herbivores that break down food particles, primarily sea grasses, through microbial fermentation. However, the microbial community and its role in health and disease is still largely unexplored. In this study, we investigated and compared the fecal bacterial communities of eight wild-captured green turtles to four stranded turtles in the central Great Barrier Reef regions that include Bowen and Townsville. We used high-throughput sequencing analysis targeting the hypervariable V1-V3 regions of the bacterial 16S rRNA gene. At the phylum level, Firmicutes predominated among wild-captured green turtles, followed by Bacteroidetes and Proteobacteria. In contrast, Proteobacteria (Gammaproteobacteria) was the most significantly dominant phylum among all stranded turtles, followed by Bacteroidetes and Firmicutes. In addition, Fusobacteria was also significantly abundant in stranded turtles. No significant differences were found between the wild-captured turtles in Bowen and Townsville. At the family level, the core bacterial community consisted of 25 families that were identified in both the wild-captured and stranded green turtles, while two unique sets of 14 families each were only found in stranded or wild-captured turtles. The predominance of Bacteroides in all groups indicates the importance of these bacteria in turtle gut health. In terms of bacterial diversity and richness, wild-captured green turtles showed a higher bacterial diversity and richness compared with stranded turtles. The marked differences in the bacterial communities between wild-captured and stranded turtles suggest the possible dysbiosis in stranded turtles in addition to potential causal agents. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Measurement of DNA integrity in marine gastropods as biomarker of genotoxicity

Digital Repository Service at National Institute of Oceanography (India)

Sarkar, A.; Vashistha, D.; Gupta, N.; Malik, K.; Gaitonde, D.C.S.

to identify the hot spot of pollution due to genotoxic compounds, the DNA damage was measured in terms of the loss of DNA integrity in marine gastropods due to the occurrence of DNA strand breaks following the technique of time dependent partially alkaline...

Harbor porpoise Phocoena phocoena strandings on the Dutch coast: No genetic structure, but evidence of inbreeding

Science.gov (United States)

van der Plas-Duivesteijn, Suzanne J.; Smit, Femmie J. L.; van Alphen, Jacques J. M.; Kraaijeveld, Ken

2015-03-01

Conservation management in the North Sea is often motivated by the population size of marine mammals, like harbor porpoises Phocoena phocoena. In the Dutch part of the North Sea, sighting and stranding data are used to estimate population sizes, but these data give little insight into genetic structuring of the population. In this study we investigated genetic structure among animals stranded at different locations and times of year. We also tested whether there is a link between stranding and necropsy data, and genetic diversity. We made use of both mitochondrial (mtDNA) and microsatellite DNA analysis of samples from dead stranded porpoises along the Dutch coast during 2007. mtDNA analysis showed 6 variable positions in the control region, defining 3 different haplotypes. mtDNA haplotypes were not randomly distributed along the Dutch coastline. However, microsatellite analysis showed that these mtDNA haplotypes did not represent separate groups on a nuclear level. Furthermore, microsatellite analysis revealed no genotypic differences between seasons, locations or genders. The results of this study indicate that the Dutch population is panmictic. In contrast, heterozygosity levels were low, indicating some level of inbreeding in this population. However, this was not corroborated by other indices of inbreeding. This research provided insight into genetic structuring of stranded porpoises in 2007, but data from multiple years should be included to be able to help estimate population sizes.

Enhancing User Access to Australian marine data - the Australian Ocean Data Network

Science.gov (United States)

Proctor, R.; Mancini, S.; Blain, P. J.

2017-12-01

The Integrated Marine Observing System (IMOS) is a national project funded by the Australian government established to deliver ocean observations to the marine and climate science community. Now in its 10th year its mission is to undertake systematic and sustained observations and to turn them into data, products and analyses that can be freely used and reused for broad societal benefits. As IMOS has matured as an observing system the expectation of the system's availability and reliability has also increased and IMOS is now seen as delivering `operational' information; it does this through the Australian Ocean Data Network (AODN). The AODN runs its services in the commercial cloud service Amazon Web Services. This has enabled the AODN to improve the system architecture, utilizing more advanced features like object storage (S3 - Simple Storage Service) and autoscaling features, and introducing new checking and logging procedures in a pipeline approach. This has improved data availability and resilience while protecting against human errors in data handling and providing a more efficient ingestion process. Many of these features are available through AODN to the wider Australian marine and science community enabling the `family' of AODN to grow, thereby enabling rapid access to an increasing collection of ocean observations.

Persistent marine debris

International Nuclear Information System (INIS)

Levy, E.M.

1992-01-01

In this paper the distribution of persistent marine debris, adrift on world oceans and stranded on beaches globally, is reviewed and related to the known inputs and transport by the major surface currents. Since naturally occurring processes eventually degrade petroleum in the environment, international measures to reduce the inputs have been largely successful in alleviating oil pollution on a global, if not on a local, scale. Many plastics, however, are so resistant to natural degradation that merely controlling inputs will be insufficient, and more drastic and costly measures will be needed to cope with the emerging global problem posed by these materials

Incorporating Local Wisdom Sasi into Marine Zoning to Increase the Resilience of a Marine Protected Area Network in Raja Ampat, Indonesia.

Science.gov (United States)

Purwanto, P., Jr.; Mangubhai, S.; Muhajir, M.; Hidayat, N. I.; Rumetna, L.; Awaludinnoer, A.; Thebu, K.

2016-02-01

The Raja Ampat government and local communities established 6 Marine Protected Areas (MPAs) in 2007 to protect the unique marine biodiversity and ensure sustainable fisheries in West Papua, Indonesia. Increasing human populations resulting in overfishing and the use of destructive fishing practices are the main threats and challenges the region faces. Biophysical, socioeconomic and climate change criteria and factors were developed for zoning the Raja Ampat MPA network. Resilience principles such as replication, habitat representation, protection of critical habitat and connectivity were applied to the final zoning design. Reef resilience data using global monitoring protocols were collected to provide insights into the resilience of different reefs to further guide zoning. Resilience rankings showed that fishing pressure on reef fish communities especially on piscivores, herbivores and excavators was the main factor lowering resilience in MPAs. In addition data were collected on `sasi' areas throughout the MPAs. Sasi is a type of traditional resource management practice used by local communities to open and close areas to fishing single or multiple fisheries species. Once the fishery recovers local communities then harvest the species for food or sale. Raja Ampat MPAs network managed as multi-objective zoning system. The current zoning system explicitly recognizes community sasi within Traditional Use Zones, which often are adjacent or close to No-Take Zones. The explicit inclusion of sasi areas within zoning plans for the MPAs will likely lead to good compliance by local communities, and the increase fish biomass. Improving the management of fisheries through the incorporation of traditional fisheries management will therefore increase the overall resilience of coral reefs in the Raja Ampat MPA network.

Recovery trajectories of kelp forest animals are rapid yet spatially variable across a network of temperate marine protected areas

OpenAIRE

Caselle, JE; Rassweiler, A; Hamilton, SL; Warner, RR

2015-01-01

© 2015, Nature Publishing Group. All rights reserved. Oceans currently face a variety of threats, requiring ecosystem-based approaches to management such as networks of marine protected areas (MPAs). We evaluated changes in fish biomass on temperate rocky reefs over the decade following implementation of a network of MPAs in the northern Channel Islands, California. We found that the biomass of targeted (i.e. fished) species has increased consistently inside all MPAs in the network, with an e...

KARAKTERISTIK ORIENTED STRAND BOARD DARI KAYU AKASIA DAN AFRIKA BERDASARKAN PENYUSUNAN ARAH STRAND

Directory of Open Access Journals (Sweden)

Nurhaida

2008-04-01

Full Text Available The research objectives arc to evaluate physical and mechanical properties of OSB based on strands orientation; and to evaluate physical and mechanical properties of OSB made from akasia wood (Acacia mangium Wild and afrika wood (Maesopsis eminii Engl. Akasia and afrika wood are used for OSB strand material with phenol formaldehyde (PF as adhesives and addition of paraffin. OSB made in this research is consist of three plies whereas are differed into eight (8 strand orientations. In the making process, hot press was carried out at 160OC and pressure 25kg.cm-2 for 15 minutes. Determination of OSB physical and mechanical properties is referred to JIS A 5908-2003. Result showed that strand orientations has no affect to OSB physical properties except for linicr swelling 24h, but it significantly influence all mechanical properties of OSB. Wood species have an effect on mechanical properties of OSB in the dry test, wet MOE lengthwise test and OSB physical properties, particularly to OSB density and water absorbing capability at 2h and 24h. All of OSB physical properties arc meet JIS A 5908-2003 standard, but not all of the mechanical properties such as dry MOE lengthwise, dry MOE and MOR widthwise. The best physical and mechanical properties is presented by OSB made from akasia wood in strand orientation F, G, Band C whereas all parameters meet JIS A 5908-2003 standard. In comparation with strand orientation B that is frequent used in industry, strand orientation F and G arc proficient to raise the modulus elasticity value (MOE and strength (MOR as much as 167.81-231.65% and 89.73-109.87%, respectively; especially in widthwise board application. Furthermore, strand orientation F and G arc more flexible as structural components

Structural features of single-stranded integron cassette attC sites and their role in strand selection.

Directory of Open Access Journals (Sweden)

Marie Bouvier

2009-09-01

Full Text Available We recently showed that cassette integration and deletion in integron platforms were occurring through unconventional site-specific recombination reactions involving only the bottom strand of attC sites. The lack of sequence conservation among attC sites led us to hypothesize that sequence-independent structural recognition determinants must exist within attC sites. The structural data obtained from a synaptic complex of the Vibrio cholerae integrase with the bottom strand of an attC site has shown the importance of extra helical bases (EHB inside the stem-loop structure formed from the bottom strand. Here, we systematically determined the contribution of three structural elements common to all known single-stranded attC site recombination substrates (the EHBs, the unpaired central spacer (UCS, and the variable terminal structure (VTS to strand choice and recombination. Their roles have been evaluated in vivo in the attIxattC reaction context using the suicide conjugation assay we previously developed, but also in an attCxattC reaction using a deletion assay. Conjugation was used to deliver the attC sites in single-stranded form. Our results show that strand choice is primarily directed by the first EHB, but the presence of the two other EHBs also serves to increase this strand selection. We found that the structure of the central spacer is essential to achieve high level recombination of the bottom strand, suggesting a dual role for this structure in active site exclusion and for hindering the reverse reaction after the first strand exchange. Moreover, we have shown that the VTS has apparently no role in strand selectivity.

Five-Strand versus Four-Strand Hamstring Tendon Graft Technique for Anterior Cruciate Ligament Reconstruction: A Biomechanical Comparison.

Science.gov (United States)

Vaillant, Eric R; Parks, Brent G; Camire, Lyn M; Hinton, Richard Y

2017-11-01

The aim of this article is to compare diameter and stiffness, displacement, and strain in a five-strand versus four-strand hamstring graft for anterior cruciate ligament reconstruction. Eight matched pairs of lower extremities underwent four-strand or five-strand hamstring graft reconstruction. Diameter was significantly higher in the five-strand versus the four-strand construct ( p  = 0.002). No significant difference was found between the groups in construct displacement or stiffness. Significantly higher strain was observed in the inner limb versus the outer limb in the four-strand construct ( p  = 0.001) and in the inner limb versus the fifth limb in the 5-strand construct ( p  = 0.004). A fifth limb added to a four-strand hamstring graft significantly increased graft diameter but did not significantly change stiffness or displacement, suggesting that attachment of additional graft material via suture did not provide for full incorporation of the added limb into the graft at time zero. The inner limb in both constructs absorbed significantly greater load than did other limbs. The use of suture to attach additional material to a four-strand hamstring graft may not contribute to improved biomechanical qualities of the graft at time zero. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Modelling Toehold-Mediated RNA Strand Displacement

OpenAIRE

Šulc, Petr; Ouldridge, Thomas E.; Romano, Flavio; Doye, Jonathan P.K.; Louis, Ard A.

2015-01-01

We study the thermodynamics and kinetics of an RNA toehold-mediated strand displacement reaction with a recently developed coarse-grained model of RNA. Strand displacement, during which a single strand displaces a different strand previously bound to a complementary substrate strand, is an essential mechanism in active nucleic acid nanotechnology and has also been hypothesized to occur in vivo. We study the rate of displacement reactions as a function of the length of the toehold and temperat...

An antemortem guide for the assessment of stranded Australian sea snakes (Hydrophiinae).

Science.gov (United States)

Gillett, Amber K; Flint, Mark; Mills, Paul C

2014-12-01

Marine snakes of the subfamily Hydrophiinae are obligate ocean dwellers, unlike their amphibious counterparts, the sea kraits (Laticaudinae), and as such they are often referred to as 'true' sea snakes. This specialization means that the presence of a true sea snake on a beach is atypical and likely indicates disease or injury. Traumatic injuries such as eye, jaw, and spinal lesions have been observed in stranded sea snakes and may present as acute injury or progress to chronic debilitation. Diseases, such as neoplasia, leukemia, and parasite overburden, have also been seen in wild sea snakes, and these animals may present similarly. Sick, moribund, or deceased sea snakes are intermittently found washed ashore along Australian beaches, and these specimens may prove valuable as bioindicators of marine health. This review is intended as a guide to the diagnostic investigation of sick or injured sea snakes by suitably qualified people.

Excess single-stranded DNA inhibits meiotic double-strand break repair.

Directory of Open Access Journals (Sweden)

Rebecca Johnson

2007-11-01

Full Text Available During meiosis, self-inflicted DNA double-strand breaks (DSBs are created by the protein Spo11 and repaired by homologous recombination leading to gene conversions and crossovers. Crossover formation is vital for the segregation of homologous chromosomes during the first meiotic division and requires the RecA orthologue, Dmc1. We analyzed repair during meiosis of site-specific DSBs created by another nuclease, VMA1-derived endonuclease (VDE, in cells lacking Dmc1 strand-exchange protein. Turnover and resection of the VDE-DSBs was assessed in two different reporter cassettes that can repair using flanking direct repeat sequences, thereby obviating the need for a Dmc1-dependent DNA strand invasion step. Access of the single-strand binding complex replication protein A, which is normally used in all modes of DSB repair, was checked in chromatin immunoprecipitation experiments, using antibody against Rfa1. Repair of the VDE-DSBs was severely inhibited in dmc1Delta cells, a defect that was associated with a reduction in the long tract resection required to initiate single-strand annealing between the flanking repeat sequences. Mutants that either reduce Spo11-DSB formation or abolish resection at Spo11-DSBs rescued the repair block. We also found that a replication protein A component, Rfa1, does not accumulate to expected levels at unrepaired single-stranded DNA (ssDNA in dmc1Delta cells. The requirement of Dmc1 for VDE-DSB repair using flanking repeats appears to be caused by the accumulation of large quantities of ssDNA that accumulate at Spo11-DSBs when Dmc1 is absent. We propose that these resected DSBs sequester both resection machinery and ssDNA binding proteins, which in wild-type cells would normally be recycled as Spo11-DSBs repair. The implication is that repair proteins are in limited supply, and this could reflect an underlying mechanism for regulating DSB repair in wild-type cells, providing protection from potentially harmful effects

Spatial, socio-economic, and ecological implications of incorporating minimum size constraints in marine protected area network design.

Science.gov (United States)

Metcalfe, Kristian; Vaughan, Gregory; Vaz, Sandrine; Smith, Robert J

2015-12-01

Marine protected areas (MPAs) are the cornerstone of most marine conservation strategies, but the effectiveness of each one partly depends on its size and distance to other MPAs in a network. Despite this, current recommendations on ideal MPA size and spacing vary widely, and data are lacking on how these constraints might influence the overall spatial characteristics, socio-economic impacts, and connectivity of the resultant MPA networks. To address this problem, we tested the impact of applying different MPA size constraints in English waters. We used the Marxan spatial prioritization software to identify a network of MPAs that met conservation feature targets, whilst minimizing impacts on fisheries; modified the Marxan outputs with the MinPatch software to ensure each MPA met a minimum size; and used existing data on the dispersal distances of a range of species found in English waters to investigate the likely impacts of such spatial constraints on the region's biodiversity. Increasing MPA size had little effect on total network area or the location of priority areas, but as MPA size increased, fishing opportunity cost to stakeholders increased. In addition, as MPA size increased, the number of closely connected sets of MPAs in networks and the average distance between neighboring MPAs decreased, which consequently increased the proportion of the planning region that was isolated from all MPAs. These results suggest networks containing large MPAs would be more viable for the majority of the region's species that have small dispersal distances, but dispersal between MPA sets and spill-over of individuals into unprotected areas would be reduced. These findings highlight the importance of testing the impact of applying different MPA size constraints because there are clear trade-offs that result from the interaction of size, number, and distribution of MPAs in a network. © 2015 Society for Conservation Biology.

Marine debris ingestion by Magellanic penguins, Spheniscus magellanicus (Aves: Sphenisciformes), from the Brazilian coastal zone.

Science.gov (United States)

Brandão, Martha L; Braga, Karina M; Luque, José L

2011-10-01

Magellanic penguins (Spheniscus magellanicus) are non-breeding winter visitors to the Brazilian coast. In 2008 and 2010, plastic items and other marine debris were found in the stomachs and intestines of 15% of 175 dead penguins collected in the Lagos Region of the state of Rio de Janeiro. One bird had its stomach perforated by a plastic straw, which may have caused its death. There are few records of penguins ingesting plastic litter, but previous studies have found similar levels of debris ingestion among Magellanic penguins stranded on the Brazilian coast (35.8% of 397 birds). The high incidence of marine debris in this species in Brazil may result at least in part from the predominance of juveniles reaching these waters, as juvenile penguins may have a broader diet than adults. It is unclear to what extent plastic ingestion affects the mortality rate in this species and whether the incidence in stranded birds reflects that in the entire population. The present study addresses the increasing impact of plastic debris on marine life. Copyright © 2011 Elsevier Ltd. All rights reserved.

La Spezia and the research network for outreach and education in marine sciences.

Science.gov (United States)

Locritani, Marina; Furia, Stefania; Giacomazzi, Fabio; Merlino, Silvia; Mori, Anna; Nacini, Francesca; Nardi, Elisabetta; Stroobant, Mascha; Talamoni, Roberta; Zocco, Olivia

2013-04-01

La Spezia is a small town located in the southeastern corner of the Liguria Region (Italy). The close relationship with the sea conditioned the ancient and recent activities of the town that embraces the namesake gulf. The Gulf of La Spezia overlooks on the Liguria Sea which is characterized by a high biodiversity, due to the heritage of coastal habitats, where numerous interesting species to preserve live, often a priority for the EC Directives. Therefore, along the Liguria arc, five coastal Marine Protected Areas have been instituted, two of them insist in La Spezia Province: the Marine Protected Areas of Cinque Terre National Park and Porto Venere Regional Park, both included in the UNESCO World Heritage Site. Moreover, the importance of the cetacean communities in the Ligurian Sea led to the establishment of the Cetacean Sanctuary. Resulting from a positive geographic coincidence, six Research Institutions are located in La Spezia: CMRE-NATO (Centre for Maritime Research and Experimentation, formerly NURC-NATO Undersea Research Centre), CNR (National Research Council), CSSN (Naval Experimentation and Support Centre - Navy), ENEA (Italian National Agency for New Technologies, Energy and Sustainable Economic Development), INGV (National Institute of Geophysics and Volcanology), Polo Universitario Marconi (University of Genoa - seat of La Spezia). These Institutions share a long time experience of work at sea and in coastal environments according to their different scientific interests (biology, engineering, geology, physic, and oceanography). Moreover, in 2009 the Liguria Region promoted the institution of the Liguria Cluster of Marine Technologies (Distretto Ligure delle Tecnologie Marine), whose core target is the regional development of marine technologies and science. This unique concentration of Research Institutes, Marine Protected Areas and sea activities (civil and military) brought to implement a collaborative network among the scientific and territorial

Smart Query Answering for Marine Sensor Data

Directory of Open Access Journals (Sweden)

Paulo de Souza

2011-03-01

Full Text Available We review existing query answering systems for sensor data. We then propose an extended query answering approach termed smart query, specifically for marine sensor data. The smart query answering system integrates pattern queries and continuous queries. The proposed smart query system considers both streaming data and historical data from marine sensor networks. The smart query also uses query relaxation technique and semantics from domain knowledge as a recommender system. The proposed smart query benefits in building data and information systems for marine sensor networks.

Smart query answering for marine sensor data.

Science.gov (United States)

Shahriar, Md Sumon; de Souza, Paulo; Timms, Greg

2011-01-01

We review existing query answering systems for sensor data. We then propose an extended query answering approach termed smart query, specifically for marine sensor data. The smart query answering system integrates pattern queries and continuous queries. The proposed smart query system considers both streaming data and historical data from marine sensor networks. The smart query also uses query relaxation technique and semantics from domain knowledge as a recommender system. The proposed smart query benefits in building data and information systems for marine sensor networks.

Persistence of self-recruitment and patterns of larval connectivity in a marine protected area network

KAUST Repository

Berumen, Michael L.

2012-02-01

The use of marine protected area (MPA) networks to sustain fisheries and conserve biodiversity is predicated on two critical yet rarely tested assumptions. Individual MPAs must produce sufficient larvae that settle within that reserve\\'s boundaries to maintain local populations while simultaneously supplying larvae to other MPA nodes in the network that might otherwise suffer local extinction. Here, we use genetic parentage analysis to demonstrate that patterns of self-recruitment of two reef fishes (Amphiprion percula and Chaetodon vagabundus) in an MPA in Kimbe Bay, Papua New Guinea, were remarkably consistent over several years. However, dispersal from this reserve to two other nodes in an MPA network varied between species and through time. The stability of our estimates of self-recruitment suggests that even small MPAs may be self-sustaining. However, our results caution against applying optimization strategies to MPA network design without accounting for variable connectivity among species and over time. 2012 The Authors.

Radiobiology of DNA strand breakage

International Nuclear Information System (INIS)

Johansen, I.

1975-01-01

The yield of single-strand breaks in lambda DNA within lysogenic host bacteria was measured after exposure to 4-MeV electrons (50 msec) and rapid transfer (45 msec) to alkaline detergent. In nitrogen anoxia the yield was 1.2 x 10 -12 DNA single-strand breaks per rad per dalton, and under full oxygenation the yield increased to 5 x 10 -12 breaks per rad per dalton. A search for the presence of fast repair mechanisms failed to demonstrate the presence of any mechanism for repair of strand breaks operating within a fraction of a second. Strand breaks produced in the presence of oxygen were repaired in 30--40 sec, while breaks produced under anoxia were rejoined even slower. A functional product from the polAl gene was needed for the rejoining of the broken molecules. Intermediate levels of DNA strand breakage seen at low concentrations of oxygen are dependent on the concentration of cellular sulfhydryl compounds, suggesting that in strand breakage oxygen and hydrogen donors compete for reactions with radiation-induced transients in the DNA. Intercomparisons of data on radiation-induced lethality of cells and single-strand breaks in episomal DNA allow the distinction between two classes of radiation-induced radicals, R 1 and R 2 , with different chemical properties; R 1 reacts readily with oxygen and N-oxyls under formation of potentially lethal products. The reactivity of oxygen in this reaction is 30--40 times higher than that of TMPN. R 2 reacts 16 times more readily than R 1 with oxygen under formation of single-strand breaks in the DNA. R 2 does not react with N-oxyls

Theoretical analysis on ac loss properties of two-strand parallel conductors composed of superconducting multifilamentary strands

CERN Document Server

Iwakuma, M; Funaki, K

2002-01-01

The ac loss properties of two-strand parallel conductors composed of superconducting multifilamentary strands were theoretically investigated. The constituent strands generally need to be insulated and transposed for the sake of uniform current distribution and low ac loss. In case the transposition points deviate from the optimum ones, shielding current is induced according to the interlinkage magnetic flux of the twisted loop enclosed by the insulated strands and the contact resistances at the terminals. It produces an additional ac loss. Supposing a simple situation where a two-strand parallel conductor with one-point transposition is exposed to a uniform ac magnetic field, the basic equations for the magnetic field were proposed and the theoretical expressions of the additional ac losses derived. As a result, the following features were shown. The additional ac loss in the non-saturation case, where the induced shielding current is less than the critical current of a strand, is proportional to the square ...

European Marine Observation Data Network - EMODnet Physics

Science.gov (United States)

Manzella, Giuseppe M. R.; Novellino, Antonio; D'Angelo, Paolo; Gorringe, Patrick; Schaap, Dick; Pouliquen, Sylvie; Loubrieu, Thomas; Rickards, Lesley

2015-04-01

The EMODnet-Physics portal (www.emodnet-physics.eu) makes layers of physical data and their metadata available for use and contributes towards the definition of an operational European Marine Observation and Data Network (EMODnet). It is based on a strong collaboration between EuroGOOS associates and its regional operational systems (ROOSs), and it is bringing together two very different marine communities: the "real time" ocean observing institute/centers and the National Oceanographic Data Centres (NODCs) that are in charge of ocean data validation, quality check and update for marine environmental monitoring. The EMODnet-Physics is a Marine Observation and Data Information System that provides a single point of access to near real time and historical achieved data (www.emodnet-physics.eu/map) it is built on existing infrastructure by adding value and avoiding any unless complexity, it provides data access to users, it is aimed at attracting new data holders, better and more data. With a long-term vision for a pan European Ocean Observation System sustainability, the EMODnet-Physics is supporting the coordination of the EuroGOOS Regional components and the empowerment and improvement of their data management infrastructure. In turn, EMODnet-Physics already implemented high-level interoperability features (WMS, Web catalogue, web services, etc…) to facilitate connection and data exchange with the ROOS and the Institutes within the ROOSs (www.emodnet-physics.eu/services). The on-going EMODnet-Physics structure delivers environmental marine physical data from the whole Europe (wave height and period, temperature of the water column, wind speed and direction, salinity of the water column, horizontal velocity of the water column, light attenuation, and sea level) as monitored by fixed stations, ARGO floats, drifting buoys, gliders, and ferry-boxes. It does provide discovering of data sets (both NRT - near real time - and Historical data sets), visualization and free

Tissue heavy metal concentrations of stranded California sea lions (Zalophus californianus) in Southern California

Energy Technology Data Exchange (ETDEWEB)

Harper, Erin R. [SeaWorld San Diego, 500 SeaWorld Drive, San Diego, CA 92109 (United States)]. E-mail: erin-harper@hotmail.com; St Leger, Judy A. [SeaWorld San Diego, 500 SeaWorld Drive, San Diego, CA 92109 (United States); Westberg, Jody A. [SeaWorld San Diego, 500 SeaWorld Drive, San Diego, CA 92109 (United States); Mazzaro, Lisa [Mystic Aquarium and Institute for Exploration, 55 Coogan Blvd, Mystic, CT 06355 (United States); Schmitt, Todd [SeaWorld San Diego, 500 SeaWorld Drive, San Diego, CA 92109 (United States); Reidarson, Tom H. [SeaWorld San Diego, 500 SeaWorld Drive, San Diego, CA 92109 (United States); Tucker, Melinda [SeaWorld San Diego, 500 SeaWorld Drive, San Diego, CA 92109 (United States); Cross, Dee H. [SeaWorld San Diego, 500 SeaWorld Drive, San Diego, CA 92109 (United States); Puschner, Birgit [California Animal Health and Food Safety Laboratory System, School of Veterinary Medicine, University of California at Davis, One Shields Avenue, Davis, CA 95616 (United States)

2007-06-15

Concentrations of nine heavy metals (As, Cd, Cu, Fe, Hg, Pb, Mn, Mo and Zn) were determined in the hepatic and renal tissues of 80 stranded California sea lions (Zalophus californianus). Significant age-dependant increases were observed in liver and kidney concentrations of cadmium and mercury, and renal zinc concentrations. Hepatic iron concentrations were significantly higher in females than males. Animals with suspected domoic acid associated pathological findings had significantly higher concentrations of liver and kidney cadmium; and significantly higher liver mercury concentrations when compared to animals classified with infectious disease or traumatic mortality. Significantly higher hepatic burdens of molybdenum and zinc were found in animals that died from infectious diseases. This is the largest study of tissue heavy metal concentrations in California sea lions to date. These data demonstrate how passive monitoring of stranded animals can provide insight into environmental impacts on marine mammals. - Tissue heavy metal concentrations are valuable in population and environmental monitoring.

Asymmetric strand segregation: epigenetic costs of genetic fidelity?

Directory of Open Access Journals (Sweden)

Diane P Genereux

2009-06-01

Full Text Available Asymmetric strand segregation has been proposed as a mechanism to minimize effective mutation rates in epithelial tissues. Under asymmetric strand segregation, the double-stranded molecule that contains the oldest DNA strand is preferentially targeted to the somatic stem cell after each round of DNA replication. This oldest DNA strand is expected to have fewer errors than younger strands because some of the errors that arise on daughter strands during their synthesis fail to be repaired. Empirical findings suggest the possibility of asymmetric strand segregation in a subset of mammalian cell lineages, indicating that it may indeed function to increase genetic fidelity. However, the implications of asymmetric strand segregation for the fidelity of epigenetic information remain unexplored. Here, I explore the impact of strand-segregation dynamics on epigenetic fidelity using a mathematical-modelling approach that draws on the known molecular mechanisms of DNA methylation and existing rate estimates from empirical methylation data. I find that, for a wide range of starting methylation densities, asymmetric -- but not symmetric -- strand segregation leads to systematic increases in methylation levels if parent strands are subject to de novo methylation events. I found that epigenetic fidelity can be compromised when enhanced genetic fidelity is achieved through asymmetric strand segregation. Strand segregation dynamics could thus explain the increased DNA methylation densities that are observed in structured cellular populations during aging and in disease.

Climate-driven environmental changes around 8,200 years ago favoured increases in cetacean strandings and Mediterranean hunter-gatherers exploited them.

Science.gov (United States)

Mannino, Marcello A; Talamo, Sahra; Tagliacozzo, Antonio; Fiore, Ivana; Nehlich, Olaf; Piperno, Marcello; Tusa, Sebastiano; Collina, Carmine; Di Salvo, Rosaria; Schimmenti, Vittoria; Richards, Michael P

2015-11-17

Cetacean mass strandings occur regularly worldwide, yet the compounded effects of natural and anthropogenic factors often complicate our understanding of these phenomena. Evidence of past stranding episodes may, thus, be essential to establish the potential influence of climate change. Investigations on bones from the site of Grotta dell'Uzzo in North West Sicily (Italy) show that the rapid climate change around 8,200 years ago coincided with increased strandings in the Mediterranean Sea. Stable isotope analyses on collagen from a large sample of remains recovered at this cave indicate that Mesolithic hunter-gatherers relied little on marine resources. A human and a red fox dating to the 8.2-kyr-BP climatic event, however, acquired at least one third of their protein from cetaceans. Numerous carcasses should have been available annually, for at least a decade, to obtain these proportions of meat. Our findings imply that climate-driven environmental changes, caused by global warming, may represent a serious threat to cetaceans in the near future.

A Bacteriophage-Related Chimeric Marine Virus Infecting Abalone

Science.gov (United States)

Zhuang, Jun; Cai, Guiqin; Lin, Qiying; Wu, Zujian; Xie, Lianhui

2010-01-01

Marine viruses shape microbial communities with the most genetic diversity in the sea by multiple genetic exchanges and infect multiple marine organisms. Here we provide proof from experimental infection that abalone shriveling syndrome-associated virus (AbSV) can cause abalone shriveling syndrome. This malady produces histological necrosis and abnormally modified macromolecules (hemocyanin and ferritin). The AbSV genome is a 34.952-kilobase circular double-stranded DNA, containing putative genes with similarity to bacteriophages, eukaryotic viruses, bacteria and endosymbionts. Of the 28 predicted open reading frames (ORFs), eight ORF-encoded proteins have identifiable functional homologues. The 4 ORF products correspond to a predicted terminase large subunit and an endonuclease in bacteriophage, and both an integrase and an exonuclease from bacteria. The other four proteins are homologous to an endosymbiont-derived helicase, primase, single-stranded binding (SSB) protein, and thymidylate kinase, individually. Additionally, AbSV exhibits a common gene arrangement similar to the majority of bacteriophages. Unique to AbSV, the viral genome also contains genes associated with bacterial outer membrane proteins and may lack the structural protein-encoding ORFs. Genomic characterization of AbSV indicates that it may represent a transitional form of microbial evolution from viruses to bacteria. PMID:21079776

A bacteriophage-related chimeric marine virus infecting abalone.

Directory of Open Access Journals (Sweden)

Jun Zhuang

Full Text Available Marine viruses shape microbial communities with the most genetic diversity in the sea by multiple genetic exchanges and infect multiple marine organisms. Here we provide proof from experimental infection that abalone shriveling syndrome-associated virus (AbSV can cause abalone shriveling syndrome. This malady produces histological necrosis and abnormally modified macromolecules (hemocyanin and ferritin. The AbSV genome is a 34.952-kilobase circular double-stranded DNA, containing putative genes with similarity to bacteriophages, eukaryotic viruses, bacteria and endosymbionts. Of the 28 predicted open reading frames (ORFs, eight ORF-encoded proteins have identifiable functional homologues. The 4 ORF products correspond to a predicted terminase large subunit and an endonuclease in bacteriophage, and both an integrase and an exonuclease from bacteria. The other four proteins are homologous to an endosymbiont-derived helicase, primase, single-stranded binding (SSB protein, and thymidylate kinase, individually. Additionally, AbSV exhibits a common gene arrangement similar to the majority of bacteriophages. Unique to AbSV, the viral genome also contains genes associated with bacterial outer membrane proteins and may lack the structural protein-encoding ORFs. Genomic characterization of AbSV indicates that it may represent a transitional form of microbial evolution from viruses to bacteria.

Clinical relevance of novel Otarine herpesvirus-3 in California sea lions (Zalophus californianus: lymphoma, esophageal ulcers, and strandings

Directory of Open Access Journals (Sweden)

Venn-Watson Stephanie

2012-12-01

Full Text Available Abstract Herpesviruses have been recognized in marine mammals, but their clinical relevance is not always easy to assess. A novel otarine herpesvirus-3 (OtHV3 was detected in a geriatric California sea lion (Zalophus californianus, and using a newly developed quantitative PCR assay paired with histology, OtHV3 was associated with esophageal ulcers and B cell lymphoblastic lymphoma in this animal. The prevalence and quantities of OtHV3 were then determined among buffy coats from 87 stranded and managed collection sea lions. Stranded sea lions had a higher prevalence of OtHV3 compared to managed collection sea lions (34.9% versus 12.5%; p = 0.04, and among the stranded sea lions, yearlings were most likely to be positive. Future epidemiological studies comparing the presence and viral loads of OtHV3 among a larger population of California sea lions with and without lymphoid neoplasia or esophageal ulcers would help elucidate the relevance of OtHV3-associated pathologies to these groups.

Modelling toehold-mediated RNA strand displacement.

Science.gov (United States)

Šulc, Petr; Ouldridge, Thomas E; Romano, Flavio; Doye, Jonathan P K; Louis, Ard A

2015-03-10

We study the thermodynamics and kinetics of an RNA toehold-mediated strand displacement reaction with a recently developed coarse-grained model of RNA. Strand displacement, during which a single strand displaces a different strand previously bound to a complementary substrate strand, is an essential mechanism in active nucleic acid nanotechnology and has also been hypothesized to occur in vivo. We study the rate of displacement reactions as a function of the length of the toehold and temperature and make two experimentally testable predictions: that the displacement is faster if the toehold is placed at the 5' end of the substrate; and that the displacement slows down with increasing temperature for longer toeholds. Copyright © 2015 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Evidence of marine debris usage by the ghost crab Ocypode quadrata (Fabricius, 1787).

Science.gov (United States)

Costa, Leonardo Lopes; Rangel, Danilo Freitas; Zalmon, Ilana Rosental

2018-03-01

Sandy beaches are sites of marine debris stranding, but the interaction of beach biota with waste is poorly studied. The objective of this study was to investigate whether the ghost crab Ocypode quadrata selects marine debris by types using a non-destructive method on sandy beaches of Southeastern Brazil. We found marine debris in 7% of 1696 surveyed burrows, and the ghost crabs selectivity was mainly by soft plastic (30%), straw (11%), rope (6%) and foam (4%). Burrows with marine debris showed higher occupation rate (~68%) compared to burrows without debris (~28%), indicating that these materials may increase the capacity of ghost crabs to memorize their burrows placement (homing). The percentage of marine debris was not always related to their amount in the drift line, but ghost crabs used more debris near urbanized areas. Future studies should test whether ghost crabs are using marine debris for feeding, homing or other mechanisms. Copyright © 2018 Elsevier Ltd. All rights reserved.

Second-strand cDNA synthesis: classical method

International Nuclear Information System (INIS)

Gubler, U.

1987-01-01

The classical scheme for the synthesis of double-stranded cDNA as it was reported in 1976 is described. Reverse transcription of mRNA with oligo(dT) as the primer generates first strands with a small loop at the 3' end of the cDNA (the end that corresponds to the 5' end of the mRNA). Subsequent removal of the mRNA by alkaline hydrolysis leaves single-stranded cDNA molecules again with a small 3' loop. This loop can be used by either reverse transcriptase or Klenow fragment of DNA polymerase I as a primer for second-strand synthesis. The resulting products are double-stranded cDNA molecules that are covalently closed at the end corresponding to the 5' end of the original mRNA. Subsequent cleavage of the short piece of single-stranded cDNA within the loop with the single-strand-specific S 1 nuclease generate open double-stranded molecules that can be used for molecular cloning in plasmids or in phage. Useful variations of this scheme have been described

The multiple personalities of Watson and Crick strands.

Science.gov (United States)

Cartwright, Reed A; Graur, Dan

2011-02-08

In genetics it is customary to refer to double-stranded DNA as containing a "Watson strand" and a "Crick strand." However, there seems to be no consensus in the literature on the exact meaning of these two terms, and the many usages contradict one another as well as the original definition. Here, we review the history of the terminology and suggest retaining a single sense that is currently the most useful and consistent. The Saccharomyces Genome Database defines the Watson strand as the strand which has its 5'-end at the short-arm telomere and the Crick strand as its complement. The Watson strand is always used as the reference strand in their database. Using this as the basis of our standard, we recommend that Watson and Crick strand terminology only be used in the context of genomics. When possible, the centromere or other genomic feature should be used as a reference point, dividing the chromosome into two arms of unequal lengths. Under our proposal, the Watson strand is standardized as the strand whose 5'-end is on the short arm of the chromosome, and the Crick strand as the one whose 5'-end is on the long arm. Furthermore, the Watson strand should be retained as the reference (plus) strand in a genomic database. This usage not only makes the determination of Watson and Crick unambiguous, but also allows unambiguous selection of reference stands for genomics. This article was reviewed by John M. Logsdon, Igor B. Rogozin (nominated by Andrey Rzhetsky), and William Martin.

The multiple personalities of Watson and Crick strands

Directory of Open Access Journals (Sweden)

Graur Dan

2011-02-01

Full Text Available Abstract Background In genetics it is customary to refer to double-stranded DNA as containing a "Watson strand" and a "Crick strand." However, there seems to be no consensus in the literature on the exact meaning of these two terms, and the many usages contradict one another as well as the original definition. Here, we review the history of the terminology and suggest retaining a single sense that is currently the most useful and consistent. Proposal The Saccharomyces Genome Database defines the Watson strand as the strand which has its 5'-end at the short-arm telomere and the Crick strand as its complement. The Watson strand is always used as the reference strand in their database. Using this as the basis of our standard, we recommend that Watson and Crick strand terminology only be used in the context of genomics. When possible, the centromere or other genomic feature should be used as a reference point, dividing the chromosome into two arms of unequal lengths. Under our proposal, the Watson strand is standardized as the strand whose 5'-end is on the short arm of the chromosome, and the Crick strand as the one whose 5'-end is on the long arm. Furthermore, the Watson strand should be retained as the reference (plus strand in a genomic database. This usage not only makes the determination of Watson and Crick unambiguous, but also allows unambiguous selection of reference stands for genomics. Reviewers This article was reviewed by John M. Logsdon, Igor B. Rogozin (nominated by Andrey Rzhetsky, and William Martin.

Designing connected marine reserves in the face of global warming.

Science.gov (United States)

Álvarez-Romero, Jorge G; Munguía-Vega, Adrián; Beger, Maria; Del Mar Mancha-Cisneros, Maria; Suárez-Castillo, Alvin N; Gurney, Georgina G; Pressey, Robert L; Gerber, Leah R; Morzaria-Luna, Hem Nalini; Reyes-Bonilla, Héctor; Adams, Vanessa M; Kolb, Melanie; Graham, Erin M; VanDerWal, Jeremy; Castillo-López, Alejandro; Hinojosa-Arango, Gustavo; Petatán-Ramírez, David; Moreno-Baez, Marcia; Godínez-Reyes, Carlos R; Torre, Jorge

2018-02-01

Marine reserves are widely used to protect species important for conservation and fisheries and to help maintain ecological processes that sustain their populations, including recruitment and dispersal. Achieving these goals requires well-connected networks of marine reserves that maximize larval connectivity, thus allowing exchanges between populations and recolonization after local disturbances. However, global warming can disrupt connectivity by shortening potential dispersal pathways through changes in larval physiology. These changes can compromise the performance of marine reserve networks, thus requiring adjusting their design to account for ocean warming. To date, empirical approaches to marine prioritization have not considered larval connectivity as affected by global warming. Here, we develop a framework for designing marine reserve networks that integrates graph theory and changes in larval connectivity due to potential reductions in planktonic larval duration (PLD) associated with ocean warming, given current socioeconomic constraints. Using the Gulf of California as case study, we assess the benefits and costs of adjusting networks to account for connectivity, with and without ocean warming. We compare reserve networks designed to achieve representation of species and ecosystems with networks designed to also maximize connectivity under current and future ocean-warming scenarios. Our results indicate that current larval connectivity could be reduced significantly under ocean warming because of shortened PLDs. Given the potential changes in connectivity, we show that our graph-theoretical approach based on centrality (eigenvector and distance-weighted fragmentation) of habitat patches can help design better-connected marine reserve networks for the future with equivalent costs. We found that maintaining dispersal connectivity incidentally through representation-only reserve design is unlikely, particularly in regions with strong asymmetric patterns of

Meteorological and oceanographic data collected from the National Data Buoy Center Coastal-Marine Automated Network (C-MAN) and moored (weather) buoys

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The National Data Buoy Center (NDBC) established the Coastal-Marine Automated Network (C-MAN) for the National Weather Service in the early 1980's. NDBC has...

Arranging eukaryotic nuclear DNA polymerases for replication: Specific interactions with accessory proteins arrange Pols α, δ, and ϵ in the replisome for leading-strand and lagging-strand DNA replication.

Science.gov (United States)

Kunkel, Thomas A; Burgers, Peter M J

2017-08-01

Biochemical and cryo-electron microscopy studies have just been published revealing interactions among proteins of the yeast replisome that are important for highly coordinated synthesis of the two DNA strands of the nuclear genome. These studies reveal key interactions important for arranging DNA polymerases α, δ, and ϵ for leading and lagging strand replication. The CMG (Mcm2-7, Cdc45, GINS) helicase is central to this interaction network. These are but the latest examples of elegant studies performed in the recent past that lead to a much better understanding of how the eukaryotic replication fork achieves efficient DNA replication that is accurate enough to prevent diseases yet allows evolution. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Cetaceans and Marine Debris: The Great Unknown

Directory of Open Access Journals (Sweden)

Mark Peter Simmonds

2012-01-01

Full Text Available Plastics and other marine debris have been found in the gastrointestinal tracts of cetaceans, including instances where large quantities of material have been found that are likely to cause impairment to digestive processes and other examples, where other morbidity and even death have resulted. In some instances, debris may have been ingested as a result of the stranding process and, in others, it may have been ingested when feeding. Those species that are suction or “ram” feeders may be most at risk. There is also evidence of entanglement of cetaceans in marine debris. However, it is usually difficult to distinguish entanglement in active fishing gear from that in lost or discarded gear. The overall significance of the threat from ingested plastics and other debris remains unclear for any population or species of cetaceans, although there are concerns for some taxa, including at the population level, and marine debris in the oceans continues to grow. Further research including the compilation of unpublished material and the investigation of important habitat areas is strongly recommended.

Integrating DNA strand-displacement circuitry with DNA tile self-assembly

Science.gov (United States)

Zhang, David Yu; Hariadi, Rizal F.; Choi, Harry M.T.; Winfree, Erik

2013-01-01

DNA nanotechnology has emerged as a reliable and programmable way of controlling matter at the nanoscale through the specificity of Watson–Crick base pairing, allowing both complex self-assembled structures with nanometer precision and complex reaction networks implementing digital and analog behaviors. Here we show how two well-developed frameworks, DNA tile self-assembly and DNA strand-displacement circuits, can be systematically integrated to provide programmable kinetic control of self-assembly. We demonstrate the triggered and catalytic isothermal self-assembly of DNA nanotubes over 10 μm long from precursor DNA double-crossover tiles activated by an upstream DNA catalyst network. Integrating more sophisticated control circuits and tile systems could enable precise spatial and temporal organization of dynamic molecular structures. PMID:23756381

Morphology and mechanical properties of multi-stranded amyloid fibrils probed by atomistic and coarse-grained simulations

International Nuclear Information System (INIS)

Yoon, Gwonchan; Lee, Myeongsang; Kim, Kyungwoo; In Kim, Jae; Joon Chang, Hyun; Baek, Inchul; Na, Sungsoo; Eom, Kilho

2015-01-01

Amyloid fibrils are responsible for pathogenesis of various diseases and exhibit the structural feature of an ordered, hierarchical structure such as multi-stranded helical structure. As the multi-strandedness of amyloid fibrils has recently been found to be highly correlated with their toxicity and infectivity, it is necessary to study how the hierarchical (i.e. multi-stranded) structure of amyloid fibril is formed. Moreover, although it has recently been reported that the nanomechanics of amyloid proteins plays a key role on the amyloid-induced pathogenesis, a critical role that the multi-stranded helical structure of the fibrils plays in their nanomechanical properties has not fully characterized. In this work, we characterize the morphology and mechanical properties of multi-stranded amyloid fibrils by using equilibrium molecular dynamics simulation and elastic network model. It is shown that the helical pitch of multi-stranded amyloid fibril is linearly proportional to the number of filaments comprising the amyloid fibril, and that multi-strandedness gives rise to improving the bending rigidity of the fibril. Moreover, we have also studied the morphology and mechanical properties of a single protofilament (filament) in order to understand the effect of cross-β structure and mutation on the structures and mechanical properties of amyloid fibrils. Our study sheds light on the underlying design principles showing how the multi-stranded amyloid fibril is formed and how the structure of amyloid fibrils governs their nanomechanical properties. (paper)

Identification of cis-acting elements on positive-strand subgenomic mRNA required for the synthesis of negative-strand counterpart in bovine coronavirus.

Science.gov (United States)

Yeh, Po-Yuan; Wu, Hung-Yi

2014-07-30

It has been demonstrated that, in addition to genomic RNA, sgmRNA is able to serve as a template for the synthesis of the negative-strand [(-)-strand] complement. However, the cis-acting elements on the positive-strand [(+)-strand] sgmRNA required for (-)-strand sgmRNA synthesis have not yet been systematically identified. In this study, we employed real-time quantitative reverse transcription polymerase chain reaction to analyze the cis-acting elements on bovine coronavirus (BCoV) sgmRNA 7 required for the synthesis of its (-)-strand counterpart by deletion mutagenesis. The major findings are as follows. (1) Deletion of the 5'-terminal leader sequence on sgmRNA 7 decreased the synthesis of the (-)-strand sgmRNA complement. (2) Deletions of the 3' untranslated region (UTR) bulged stem-loop showed no effect on (-)-strand sgmRNA synthesis; however, deletion of the 3' UTR pseudoknot decreased the yield of (-)-strand sgmRNA. (3) Nucleotides positioned from -15 to -34 of the sgmRNA 7 3'-terminal region are required for efficient (-)-strand sgmRNA synthesis. (4) Nucleotide species at the 3'-most position (-1) of sgmRNA 7 is correlated to the efficiency of (-)-strand sgmRNA synthesis. These results together suggest, in principle, that the 5'- and 3'-terminal sequences on sgmRNA 7 harbor cis-acting elements are critical for efficient (-)-strand sgmRNA synthesis in BCoV.

Fair Exchange in Strand Spaces

Directory of Open Access Journals (Sweden)

Joshua D. Guttman

2009-10-01

Full Text Available Many cryptographic protocols are intended to coordinate state changes among principals. Exchange protocols coordinate delivery of new values to the participants, e.g. additions to the set of values they possess. An exchange protocol is fair if it ensures that delivery of new values is balanced: If one participant obtains a new possession via the protocol, then all other participants will, too. Fair exchange requires progress assumptions, unlike some other protocol properties. The strand space model is a framework for design and verification of cryptographic protocols. A strand is a local behavior of a single principal in a single session of a protocol. A bundle is a partially ordered global execution built from protocol strands and adversary activities. The strand space model needs two additions for fair exchange protocols. First, we regard the state as a multiset of facts, and we allow strands to cause changes in this state via multiset rewriting. Second, progress assumptions stipulate that some channels are resilient-and guaranteed to deliver messages-and some principals are assumed not to stop at certain critical steps. This method leads to proofs of correctness that cleanly separate protocol properties, such as authentication and confidentiality, from invariants governing state evolution. G. Wang's recent fair exchange protocol illustrates the approach.

Status of marine protected areas in Egypt

Directory of Open Access Journals (Sweden)

Samy, M.

2011-06-01

Full Text Available Egypt has sought to protect its natural resources and marine biodiversity by establishing a network of six MPAs that are generally located in the Gulf of Aqaba and the Red Sea; most of them include interconnected marine and terrestrial sectors based on conserving coral reefs and accompanying systems. We assessed the present status of MPA networks that showed a set of important results manifested in some strengths (i.e. proper selection according to specific criteria, management plans, etc., and also some weaknesses (i.e. a relatively small protected proportion of the Egyptian marine territorial waters, significant pressures mainly by tourism activities, etc.. Finally, some recommendations are proposed from this work (i.e. incorporate more habitats that are not well represented in the network, especially on the Mediterranean Sea; establishing a touristic carrying capacity of each area; etc. to improve the current situation.

Rapid effects of marine reserves via larval dispersal.

Directory of Open Access Journals (Sweden)

Richard Cudney-Bueno

Full Text Available Marine reserves have been advocated worldwide as conservation and fishery management tools. It is argued that they can protect ecosystems and also benefit fisheries via density-dependent spillover of adults and enhanced larval dispersal into fishing areas. However, while evidence has shown that marine reserves can meet conservation targets, their effects on fisheries are less understood. In particular, the basic question of if and over what temporal and spatial scales reserves can benefit fished populations via larval dispersal remains unanswered. We tested predictions of a larval transport model for a marine reserve network in the Gulf of California, Mexico, via field oceanography and repeated density counts of recently settled juvenile commercial mollusks before and after reserve establishment. We show that local retention of larvae within a reserve network can take place with enhanced, but spatially-explicit, recruitment to local fisheries. Enhancement occurred rapidly (2 yrs, with up to a three-fold increase in density of juveniles found in fished areas at the downstream edge of the reserve network, but other fishing areas within the network were unaffected. These findings were consistent with our model predictions. Our findings underscore the potential benefits of protecting larval sources and show that enhancement in recruitment can be manifested rapidly. However, benefits can be markedly variable within a local seascape. Hence, effects of marine reserve networks, positive or negative, may be overlooked when only focusing on overall responses and not considering finer spatially-explicit responses within a reserve network and its adjacent fishing grounds. Our results therefore call for future research on marine reserves that addresses this variability in order to help frame appropriate scenarios for the spatial management scales of interest.

A novel Sarcocystis neurona genotype XIII is associated with severe encephalitis in an unexpectedly broad range of marine mammals from the northeastern Pacific Ocean.

Science.gov (United States)

Barbosa, Lorraine; Johnson, Christine K; Lambourn, Dyanna M; Gibson, Amanda K; Haman, Katherine H; Huggins, Jessica L; Sweeny, Amy R; Sundar, Natarajan; Raverty, Stephen A; Grigg, Michael E

2015-08-01

Sarcocystis neurona is an important cause of protozoal encephalitis among marine mammals in the northeastern Pacific Ocean. To characterise the genetic type of S. neurona in this region, samples from 227 stranded marine mammals, most with clinical or pathological evidence of protozoal disease, were tested for the presence of coccidian parasites using a nested PCR assay. The frequency of S. neurona infection was 60% (136/227) among pinnipeds and cetaceans, including seven marine mammal species not previously known to be susceptible to infection by this parasite. Eight S. neurona fetal infections identified this coccidian parasite as capable of being transmitted transplacentally. Thirty-seven S. neurona-positive samples were multilocus sequence genotyped using three genetic markers: SnSAG1-5-6, SnSAG3 and SnSAG4. A novel genotype, referred to as Type XIII within the S. neurona population genetic structure, has emerged recently in the northeastern Pacific Ocean and is significantly associated with an increased severity of protozoal encephalitis and mortality among multiple stranded marine mammal species. Published by Elsevier Ltd.

Protected DNA strand displacement for enhanced single nucleotide discrimination in double-stranded DNA.

Science.gov (United States)

Khodakov, Dmitriy A; Khodakova, Anastasia S; Huang, David M; Linacre, Adrian; Ellis, Amanda V

2015-03-04

Single nucleotide polymorphisms (SNPs) are a prime source of genetic diversity. Discriminating between different SNPs provides an enormous leap towards the better understanding of the uniqueness of biological systems. Here we report on a new approach for SNP discrimination using toehold-mediated DNA strand displacement. The distinctiveness of the approach is based on the combination of both 3- and 4-way branch migration mechanisms, which allows for reliable discrimination of SNPs within double-stranded DNA generated from real-life human mitochondrial DNA samples. Aside from the potential diagnostic value, the current study represents an additional way to control the strand displacement reaction rate without altering other reaction parameters and provides new insights into the influence of single nucleotide substitutions on 3- and 4-way branch migration efficiency and kinetics.

Internet vis-a-vis marine biology

Digital Repository Service at National Institute of Oceanography (India)

Chavan, V.S.

Internet is an amalgum of networks which reaches to more than 100 million people across the globe. The satellite-telecommunication based computer network web hosts information on every aspect of life. Marine biology related information too is being...

Identification of Cis-Acting Elements on Positive-Strand Subgenomic mRNA Required for the Synthesis of Negative-Strand Counterpart in Bovine Coronavirus

Directory of Open Access Journals (Sweden)

Po-Yuan Yeh

2014-07-01

Full Text Available It has been demonstrated that, in addition to genomic RNA, sgmRNA is able to serve as a template for the synthesis of the negative-strand [(−-strand] complement. However, the cis-acting elements on the positive-strand [(+-strand] sgmRNA required for (−-strand sgmRNA synthesis have not yet been systematically identified. In this study, we employed real-time quantitative reverse transcription polymerase chain reaction to analyze the cis-acting elements on bovine coronavirus (BCoV sgmRNA 7 required for the synthesis of its (−-strand counterpart by deletion mutagenesis. The major findings are as follows. (1 Deletion of the 5'-terminal leader sequence on sgmRNA 7 decreased the synthesis of the (−-strand sgmRNA complement. (2 Deletions of the 3' untranslated region (UTR bulged stem-loop showed no effect on (−-strand sgmRNA synthesis; however, deletion of the 3' UTR pseudoknot decreased the yield of (−-strand sgmRNA. (3 Nucleotides positioned from −15 to −34 of the sgmRNA 7 3'-terminal region are required for efficient (−-strand sgmRNA synthesis. (4 Nucleotide species at the 3'-most position (−1 of sgmRNA 7 is correlated to the efficiency of (−-strand sgmRNA synthesis. These results together suggest, in principle, that the 5'- and 3'-terminal sequences on sgmRNA 7 harbor cis-acting elements are critical for efficient (−-strand sgmRNA synthesis in BCoV.

Network Society

DEFF Research Database (Denmark)

Clausen, Lars; Tække, Jesper

2017-01-01

the five strands of theory on the network society. Each theoretical position has its specific implications for acting toward strategic goals. In its entirety, the five perspectives give a thorough understanding of the conditions for successful strategic communication in the 21st century....

Network Society

DEFF Research Database (Denmark)

Clausen, Lars; Tække, Jesper

2018-01-01

the five strands of theory on the network society. Each theoretical position has its specific implications for acting toward strategic goals. In its entirety, the five perspectives give a thorough understanding of the conditions for successful strategic communication in the 21st century....

The European Nb3Sn advanced strand development programme

International Nuclear Information System (INIS)

Vostner, A.; Salpietro, E.

2005-01-01

Strands relevant for fusion with high critical current densities and moderate hysteresis losses were developed and already produced on industrial scale. Based on these achievements EFDA-CSU Garching has launched a Nb 3 Sn strand development and procurement action inside Europe in order to assess the current status of the Nb 3 Sn strand production capability. All six addressed companies have replied positively to the strand R and D programme which includes the three major Nb 3 Sn production techniques namely the bronze, internal-tin and powder-in-tube (PIT) route. According to the strand requirements for the ITER TF conductor a critical current density of 800 A/mm 2 (at 12 T, 4.2 K and 10 μV/m) and overall strand hysteresis losses below 500 kJ/m 3 have been specified as the minimum guaranteed strand performance. The second major objective of this programme is to motivate the strand manufacturers to develop and design high performance Nb 3 Sn strands optimised for the ITER conductor. For this purpose, a target critical current density of 1100 A/mm 2 has been added to the specification. This paper describes the strategy behind the strand development programme, the actual status of the strand production as well as first preliminary results obtained from the strand suppliers

Purification of Single-Stranded cDNA Based on RNA Degradation Treatment and Adsorption Chromatography.

Science.gov (United States)

Trujillo-Esquivel, Elías; Franco, Bernardo; Flores-Martínez, Alberto; Ponce-Noyola, Patricia; Mora-Montes, Héctor M

2016-08-02

Analysis of gene expression is a common research tool to study networks controlling gene expression, the role of genes with unknown function, and environmentally induced responses of organisms. Most of the analytical tools used to analyze gene expression rely on accurate cDNA synthesis and quantification to obtain reproducible and quantifiable results. Thus far, most commercial kits for isolation and purification of cDNA target double-stranded molecules, which do not accurately represent the abundance of transcripts. In the present report, we provide a simple and fast method to purify single-stranded cDNA, exhibiting high purity and yield. This method is based on the treatment with RNase H and RNase A after cDNA synthesis, followed by separation in silica spin-columns and ethanol precipitation. In addition, our method avoids the use of DNase I to eliminate genomic DNA from RNA preparations, which improves cDNA yield. As a case report, our method proved to be useful in the purification of single-stranded cDNA from the pathogenic fungus Sporothrix schenckii.

Marine Creatures and the Sea in Bronze Age Greece: Ambiguities of Meaning

Science.gov (United States)

Berg, Ina

2013-06-01

Like most cultures, prehistoric Greek communities had an ambiguous relationship with the sea and the creatures that inhabit it. Positive and negative associations always co-existed, though the particular manifestations changed over time. By drawing together evidence of consumption of marine animals, seafaring, fishing, and iconography, this article unites disparate strands of evidence in an attempt to illuminate the relationship prehistoric Greeks had with marine creatures and the sea. Based on the marked reduction in seafood consumption after the Mesolithic and the use of marine creatures in funerary iconography in the post-palatial period, it becomes apparent that the sea—then as now—is an inherently ambiguous medium that captures both positive and negative emotions. On the one hand, the sea and the animals residing in it are strongly associated with death. On the other hand, the sea's positive dimensions, such as fertility and rebirth, are expressed in conspicuous marine consumption events.

Implementing and Innovating Marine Monitoring Approaches for Assessing Marine Environmental Status

KAUST Repository

Danovaro, Roberto; Carugati, Laura; Berzano, Marco; Cahill, Abigail E.; Carvalho, Susana; Chenuil, Anne; Corinaldesi, Cinzia; Cristina, Sonia; David, Romain; Dell'Anno, Antonio; Dzhembekova, Nina; Garcé s, Esther; Gasol, Joseph M.; Goela, Priscila; Fé ral, Jean-Pierre; Ferrera, Isabel; Forster, Rodney M.; Kurekin, Andrey A.; Rastelli, Eugenio; Marinova, Veselka; Miller, Peter I.; Moncheva, Snejana; Newton, Alice; Pearman, John K.; Pitois, Sophie G.; Reñ é , Albert; Rodrí guez-Ezpeleta, Naiara; Saggiomo, Vincenzo; Simis, Stefan G. H.; Stefanova, Kremena; Wilson, Christian; Lo Martire, Marco; Greco, Silvestro; Cochrane, Sabine K. J.; Mangoni, Olga; Borja, Angel

2016-01-01

Marine environmental monitoring has tended to focus on site-specific methods of investigation. These traditional methods have low spatial and temporal resolution and are relatively labor intensive per unit area/time that they cover. To implement the Marine Strategy Framework Directive (MSFD), European Member States are required to improve marine monitoring and design monitoring networks. This can be achieved by developing and testing innovative and cost-effective monitoring systems, as well as indicators of environmental status. Here, we present several recently developed methodologies and technologies to improve marine biodiversity indicators and monitoring methods. The innovative tools are discussed concerning the technologies presently utilized as well as the advantages and disadvantages of their use in routine monitoring. In particular, the present analysis focuses on: (i) molecular approaches, including microarray, Real Time quantitative PCR (qPCR), and metagenetic (metabarcoding) tools; (ii) optical (remote) sensing and acoustic methods; and (iii) in situ monitoring instruments. We also discuss their applications in marine monitoring within the MSFD through the analysis of case studies in order to evaluate their potential utilization in future routine marine monitoring. We show that these recently-developed technologies can present clear advantages in accuracy, efficiency and cost.

Implementing and Innovating Marine Monitoring Approaches for Assessing Marine Environmental Status

KAUST Repository

Danovaro, Roberto

2016-11-23

Marine environmental monitoring has tended to focus on site-specific methods of investigation. These traditional methods have low spatial and temporal resolution and are relatively labor intensive per unit area/time that they cover. To implement the Marine Strategy Framework Directive (MSFD), European Member States are required to improve marine monitoring and design monitoring networks. This can be achieved by developing and testing innovative and cost-effective monitoring systems, as well as indicators of environmental status. Here, we present several recently developed methodologies and technologies to improve marine biodiversity indicators and monitoring methods. The innovative tools are discussed concerning the technologies presently utilized as well as the advantages and disadvantages of their use in routine monitoring. In particular, the present analysis focuses on: (i) molecular approaches, including microarray, Real Time quantitative PCR (qPCR), and metagenetic (metabarcoding) tools; (ii) optical (remote) sensing and acoustic methods; and (iii) in situ monitoring instruments. We also discuss their applications in marine monitoring within the MSFD through the analysis of case studies in order to evaluate their potential utilization in future routine marine monitoring. We show that these recently-developed technologies can present clear advantages in accuracy, efficiency and cost.

Marine Protected Dramas: The Flaws of the Brazilian National System of Marine Protected Areas

Science.gov (United States)

Gerhardinger, Leopoldo C.; Godoy, Eduardo A. S.; Jones, Peter J. S.; Sales, Gilberto; Ferreira, Beatrice P.

2011-04-01

This article discusses the current problems and issues associated with the implementation of a National System of Marine Protected Areas in Brazil. MPA managers and higher governmental level authorities were interviewed about their perceptions of the implementation of a national MPA strategy and the recent changes in the institutional arrangement of government marine conservation agencies. Interviewees' narratives were generally pessimistic and the National System was perceived as weak, with few recognizable marine conservation outcomes on the ground. The following major flaws were identified: poor inter-institutional coordination of coastal and ocean governance; institutional crisis faced by the national government marine conservation agency; poor management within individual MPAs; problems with regional networks of marine protected areas; an overly bureaucratic management and administrative system; financial shortages creating structural problems and a disconnect between MPA policy and its delivery. Furthermore, a lack of professional motivation and a pessimistic atmosphere was encountered during many interviews, a malaise which we believe affects how the entire system is able to respond to crises. Our findings highlight the need for a better understanding of the role of `leadership' in the performance of socio-ecological systems (such as MPA networks), more effective official evaluation mechanisms, more localized audits of (and reforms if necessary to) Brazil's federal biodiversity conservation agency (ICMBio), and the need for political measures to promote state leadership and support. Continuing to focus on the designation of more MPAs whilst not fully addressing these issues will achieve little beyond fulfilling, on paper, Brazil's international marine biodiversity commitments.

Stranding survey as a framework to investigate rare cetacean records of the north and north-eastern Brazilian coasts

Directory of Open Access Journals (Sweden)

Alexandra Fernandes Costa

2017-08-01

Full Text Available Marine mammal stranding events are used as an important tool for understanding cetacean biology worldwide. Nonetheless, there are vast gaps of knowledge to be filled in for a wide range of species. Reputable information is required regarding species from large baleen whales to sperm and beaked whales, as well as pelagic dolphins. This paper describes new cetacean records from north and north-eastern Brazil, which are both the least surveyed areas regarding aquatic mammals. Regular beach surveys were conducted to recover cetacean carcasses along the coast of Pará beginning November 2005. At the coasts of the Maranhão and Piauí states, the surveys were conducted between 2003 and 2013. From 2003 to 2014, 34 strandings of cetaceans were registered. The study provides four additional species records’ in the area based on strandings (Balaenoptera borealis, Balaenoptera physalus, Peponocephala electra, and Pseudorca crassidens. A mass stranding of Guiana dolphins (Sotalia guianensis, N = 12, the most common species for the region, was reported for the first time. The records presented herein are of special concern, since they expand the knowledge on cetaceans from the Brazilian coast. In addition, this study conducted an analysis to verify the similarity between cetacean compositions described for north and north-eastern Brazil and the southern Caribbean region. The results showed a high similarity between these regions, proving the connection with the Caribbean cetacean fauna.

Marine informational governance, a conceptual framework

NARCIS (Netherlands)

Hoefnagel, E.W.J.; Vos, de B.I.; Buisman, F.C.

2013-01-01

Marine governance involves interaction between networks and actors from different types and levels of organizations. The concept of multi-level or network governance steps away from the assumptions that supra-national and national government at the macro level is the dominant policy making unit. At

15N and 13C abundances in marine environments with emphasis on biogeochemical structure of food networks

International Nuclear Information System (INIS)

Wada, E.

1987-01-01

Distributions of δ 15 N and δ 13 C for biogenic substances in the Antarctic Ocean and in the Otsuchi River estuary in Japan were investigated to construct isotope biogeochemical framework for assessing marine ecosystems. The isotopic compositions of phytoplankton were particularly low in the Antarctic Ocean. High nitrate and CO 2 concentrations in the surface sea waters, and the low light intensity seem to enhance the kinetic isotope fractionations that preferred the depletion of 15 N and 13 C in the algal body. A clear-cut linear relationship between animal δ 15 N and its trophic level was obtained in the Antarctic system. In the estuary, the variation of isotope ratios were principally governed by the mixing of land-derived organic matter, marine phytoplankton, and seagrasses. A food-chain effect of 15 N enrichment was also confirmed. An isotopically ordered structure was presented for a marine estuarine ecosystem. The isotopic abundances in a food network vary mainly because of the variation in 15 N and 13 C contents of primary producers grown under different environmental conditions and because of the enrichment of 15 N along food chains. (author)

Mariner and the ITm Superfamily of Transposons.

Science.gov (United States)

Tellier, Michael; Bouuaert, Corentin Claeys; Chalmers, Ronald

2015-04-01

The IS630-Tc1-mariner (ITm) family of transposons is one of the most widespread in nature. The phylogenetic distribution of its members shows that they do not persist for long in a given lineage, but rely on frequent horizontal transfer to new hosts. Although they are primarily selfish genomic-parasites, ITm transposons contribute to the evolution of their hosts because they generate variation and contribute protein domains and regulatory regions. Here we review the molecular mechanism of ITm transposition and its regulation. We focus mostly on the mariner elements, which are understood in the greatest detail owing to in vitro reconstitution and structural analysis. Nevertheless, the most important characteristics are probably shared across the grouping. Members of the ITm family are mobilized by a cut-and-paste mechanism and integrate at 5'-TA dinucleotide target sites. The elements encode a single transposase protein with an N-terminal DNA-binding domain and a C-terminal catalytic domain. The phosphoryl-transferase reactions during the DNA-strand breaking and joining reactions are performed by the two metal-ion mechanism. The metal ions are coordinated by three or four acidic amino acid residues located within an RNase H-like structural fold. Although all of the strand breaking and joining events at a given transposon end are performed by a single molecule of transposase, the reaction is coordinated by close communication between transpososome components. During transpososome assembly, transposase dimers compete for free transposon ends. This helps to protect the host by dampening an otherwise exponential increase in the rate of transposition as the copy number increases.

Monitoring the abundance of plastic debris in the marine environment

OpenAIRE

Ryan, Peter G.; Moore, Charles J.; van Franeker, Jan A.; Moloney, Coleen L.

2009-01-01

Plastic debris has significant environmental and economic impacts in marine systems. Monitoring is crucial to assess the efficacy of measures implemented to reduce the abundance of plastic debris, but it is complicated by large spatial and temporal heterogeneity in the amounts of plastic debris and by our limited understanding of the pathways followed by plastic debris and its long-term fate. To date, most monitoring has focused on beach surveys of stranded plastics and other litter. Infreque...

DNA strand breaks, repair, and survival in x-irradiated mammalian cells

International Nuclear Information System (INIS)

Dugle, D.L.; Gillespie, C.J.; Chapman, J.D.

1976-01-01

The yields of unrepairable single- and double-strand breaks in the DNA of x-irradiated Chinese hamster cells were measured by low-speed neutral and alkaline sucrose density gradient sedimentation in order to investigate the relation between these lesions and reproductive death. After maximal single-strand rejoining, at all doses, the number of residual single-strand breaks was twice the number of residual double-strand breaks. Both double-strand and unrepairable single-strand breaks were proportional to the square of absorbed dose, in the range 10-50 krad. No rejoining of double-strand breaks was observed. These observations suggest that, in mammalian cells, most double-strand breaks are not repairable, while all single-strand breaks are repaired except those that are sufficiently close on complementary strands to constitute double-strand breaks. Comparison with cell survival measurements at much lower doses suggests that loss of reproductive capacity corresponds to induction of approximately one double-strand break

Strand Plasticity Governs Fatigue in Colloidal Gels

Science.gov (United States)

van Doorn, Jan Maarten; Verweij, Joanne E.; Sprakel, Joris; van der Gucht, Jasper

2018-05-01

The repeated loading of a solid leads to microstructural damage that ultimately results in catastrophic material failure. While posing a major threat to the stability of virtually all materials, the microscopic origins of fatigue, especially for soft solids, remain elusive. Here we explore fatigue in colloidal gels as prototypical inhomogeneous soft solids by combining experiments and computer simulations. Our results reveal how mechanical loading leads to irreversible strand stretching, which builds slack into the network that softens the solid at small strains and causes strain hardening at larger deformations. We thus find that microscopic plasticity governs fatigue at much larger scales. This gives rise to a new picture of fatigue in soft thermal solids and calls for new theoretical descriptions of soft gel mechanics in which local plasticity is taken into account.

Detection of bacteriophage phi 6 minus-strand RNA and novel mRNA isoconformers synthesized in vivo and in vitro, by strand-separating agarose gels

International Nuclear Information System (INIS)

Pagratis, N.; Revel, H.R.

1990-01-01

Two urea-free agarose gel protocols that resolve the six individual strands of bacteriophage phi 6 dsRNA were developed and used to analyze phage RNA synthesis in vivo and in vitro. Citrate gels separate strands of the large and medium chromosomes while Tris-borate-EDTA (TBE) gels resolve the medium and small dsRNA segments. Minus strands migrate faster than plus strands on citrate gels but are retarded on TBE gels. A study of electrophoretic conditions showed that pH affects strand resolution on citrate gels, and that voltage gradient, agarose concentration, and ethidium bromide significantly alter strand migration on TBE gels. Analysis of native phi 6 RNA synthesized in vivo and in vitro showed that the large and medium message RNAs comigrate with the corresponding plus strands of denatured virion dsRNA. The small messenger RNA is exceptional. Native small mRNA was detected as three isoconformers in vivo and in vitro. The isoconformers were converted by heat denaturation to a single RNA species that comigrates with the virion s+ strand. Minus strands labeled in vivo were detected only after heat denaturation. Minus strand synthesis was detected also in heat-denatured samples from in vitro phi 6 nucleocapsid RNA polymerase reactions at pH values suboptimal for transcription

Specimen banking of marine organisms in the United States: Current status and long-term prospective

Science.gov (United States)

Becker, P.R.; Wise, S.A.; Thorsteinson, L.; Koster, B.J.; Rowles, T.

1997-01-01

A major part of the activities conducted over the last decade by the National Biomonitoring Specimen Bank (NBSB) has involved the archival of marine specimens collected by ongoing environmental monitoring programs. These archived specimens include bivalves, marine sediments, and fish tissues collected by the National Status and Trends and the Exxon Valdez Oil Spill Damage Assessment programs, and marine mammal tissues collected by the Marine Mammal Health and Stranding Response Program and the Alaska Marine Mammal Tissue Archival Project. In addition to supporting these programs, the specimens have been used to investigate circumpolar patterns of chlorinated hydrocarbon concentrations, genetic separation of marine animal stocks, baseline levels of essential and nonessential elements in marine mammals, and the potential risk to human consumers in the Arctic from anthropogenic contaminants found in local subsistence foods. The NBSB specimens represent a resource that has the potential for addressing future issues of marine environmental quality and ecosystem changes through retrospective analysis; however, an ecosystem-based food web approach would maximize this potential. The current status of the NBSB activities related to the banking of marine organisms is presented and discussed, the long-term prospective of these activities is presented, and the importance of an ecosystem-based food web monitoring approach to the value of specimen banking is discussed.

Dynamics of Leading-strand Lesion Skipping by the Replisome

Science.gov (United States)

Yeeles, Joseph T.P.; Marians, Kenneth J.

2013-01-01

SUMMARY The E. coli replisome stalls transiently when it encounters a lesion in the leading-strand template, skipping over the damage by reinitiating replication at a new primer synthesized downstream by the primase. We report here that template unwinding and lagging-strand synthesis continue downstream of the lesion at a reduced rate after replisome stalling, that one replisome is capable of skipping multiple lesions, and that the rate limiting steps of replication restart involve the synthesis and activation of the new primer downstream. We also find little support for the concept that polymerase uncoupling, where extensive lagging-strand synthesis proceeds downstream in the absence of leading-strand synthesis, involves physical separation of the leading-strand polymerase from the replisome. Instead, our data indicate that extensive uncoupled replication likely results from a failure of the leading-strand polymerase still associated with the DNA helicase and the lagging-strand polymerase that are proceeding downstream to reinitiate synthesis. PMID:24268579

Incidence of marine debris in seabirds feeding at different water depths.

Science.gov (United States)

Tavares, D C; de Moura, J F; Merico, A; Siciliano, S

2017-06-30

Marine debris such as plastic fragments and fishing gears are accumulating in the ocean at alarming rates. This study assesses the incidence of debris in the gastrointestinal tracts of seabirds feeding at different depths and found stranded along the Brazilian coast in the period 2010-2013. More than half (55%) of the species analysed, corresponding to 16% of the total number of individuals, presented plastic particles in their gastrointestinal tracts. The incidence of debris was higher in birds feeding predominantly at intermediate (3-6m) and deep (20-100m) waters than those feeding at surface (pollution has on marine life and highlight the ubiquitous and three-dimensional distribution of plastic in the oceans. Copyright © 2017 Elsevier Ltd. All rights reserved.

Connecting localized DNA strand displacement reactions

Science.gov (United States)

Mullor Ruiz, Ismael; Arbona, Jean-Michel; Lad, Amitkumar; Mendoza, Oscar; Aimé, Jean-Pierre; Elezgaray, Juan

2015-07-01

Logic circuits based on DNA strand displacement reactions have been shown to be versatile enough to compute the square root of four-bit numbers. The implementation of these circuits as a set of bulk reactions faces difficulties which include leaky reactions and intrinsically slow, diffusion-limited reaction rates. In this paper, we consider simple examples of these circuits when they are attached to platforms (DNA origamis). As expected, constraining distances between DNA strands leads to faster reaction rates. However, it also induces side-effects that are not detectable in the solution-phase version of this circuitry. Appropriate design of the system, including protection and asymmetry between input and fuel strands, leads to a reproducible behaviour, at least one order of magnitude faster than the one observed under bulk conditions.Logic circuits based on DNA strand displacement reactions have been shown to be versatile enough to compute the square root of four-bit numbers. The implementation of these circuits as a set of bulk reactions faces difficulties which include leaky reactions and intrinsically slow, diffusion-limited reaction rates. In this paper, we consider simple examples of these circuits when they are attached to platforms (DNA origamis). As expected, constraining distances between DNA strands leads to faster reaction rates. However, it also induces side-effects that are not detectable in the solution-phase version of this circuitry. Appropriate design of the system, including protection and asymmetry between input and fuel strands, leads to a reproducible behaviour, at least one order of magnitude faster than the one observed under bulk conditions. Electronic supplementary information (ESI) available. See DOI: 10.1039/C5NR02434J

Formation of double-strand breaks in DNA of γ-irradiated bacteria depending on the function of fast repair processes of DNA single-strand breaks

International Nuclear Information System (INIS)

Petrov, S.I.; Gaziev, A.I.

1980-01-01

The formation of double-strand breaks in DNA of γ-irradiated ( 60 Co)Ex coli bacteria depending on the function of fast repair processes of DNA single-strand breaks, is investigated. The profiles of sedimentation of DNA Ex coli cells, irradiated at 0-2 deg C in the salt medium and in EDTA-borate buffer, are presented. It is shown that when irradiating cells in EDTA-borate buffer, the output of single- and double strand breaks in DNA is much higher than in the case of their irradiation in the minimum salt medium. The dependence of output of single-strand and double-strand breaks depending on the radiatier doze of E coli cells in the salt medium and EDTA-borate buffer, is studied. The supposition is made on the presence of a regulative interaction between the accumulation of DNA single-breaks and their repair with the formation of double-strand breaks. The functionating of fast and superfast repair processes considerably affects the formation of double-strand breaks in DNA of a bacterium cell. A considerable amount of double-breaks registered immediately after irradiation forms due to a close position of single-strand breaks on the opposite DNA strands

Molecular network considerations in the deformation of glassy polymers

International Nuclear Information System (INIS)

Henkee, C.S.

1985-01-01

Thin films of polystyrene (PS) are crosslinked with electron irradiation and are strained in tension until regions of local plastic deformation, either crazes or plane stress deformation zones (DZ's), have grown. The behavior of the PS glass is consistent with its being a network of molecular strands of total density nu = nu/sub x/ + nu/sub e/, where nu/sub e/ is the entangled strand density, and nu/sub x/ is the density of crosslinked strands. When nu is less than 4 x 10 25 m -3 only crazes are observed. As nu increases from 4 x 10 25 to 8 x 10 -5 m -3 , only shear DZ's are observed. The local extension ratio, lambda, in the crazes and DZ's correlate well with lambda/sub max/, the maximum extension ratio of a strand in a network of density nu computed using the Porod-Kratky model. Crosslinking to still higher crosslink densities, e.g. nu = 14nu/sub e/, results in cracks that propagate in a catastrophic manner at low applied strains. An optimum nu thus exists, one not too high to suppress local shear ductility but high enough to suppress crazes which can act as crack nucleation sites. Comparison of the results in crosslinked PS with those in other linear, but entangled polymer systems implies that chain scission is the major mechanism by which strands in the entanglement network are removed in forming fibril surfaces. Craze suppression by increasing nu is due to the extra energy required to break more main chain bonds to form these surfaces

A robust network of double-strand break repair pathways governs genome integrity during C. elegans development.

NARCIS (Netherlands)

Pontier, D.B.; Tijsterman, M.

2009-01-01

To preserve genomic integrity, various mechanisms have evolved to repair DNA double-strand breaks (DSBs). Depending on cell type or cell cycle phase, DSBs can be repaired error-free, by homologous recombination, or with concomitant loss of sequence information, via nonhomologous end-joining (NHEJ)

ISOLATION AND CHARACTERIZATION OF A NOVEL MARINE BRUCELLA FROM A SOUTHERN SEA OTTER (ENHYDRA LUTRIS NEREIS), CALIFORNIA, USA.

Science.gov (United States)

Miller, Melissa A; Burgess, Tristan L; Dodd, Erin M; Rhyan, Jack C; Jang, Spencer S; Byrne, Barbara A; Gulland, Frances M D; Murray, Michael J; Toy-Choutka, Sharon; Conrad, Patricia A; Field, Cara L; Sidor, Inga F; Smith, Woutrina A

2017-04-01

We characterize Brucella infection in a wild southern sea otter ( Enhydra lutris nereis) with osteolytic lesions similar to those reported in other marine mammals and humans. This otter stranded twice along the central California coast, US over a 1-yr period and was handled extensively at two wildlife rehabilitation facilities, undergoing multiple surgeries and months of postsurgical care. Ultimately the otter was euthanized due to severe, progressive neurologic disease. Necropsy and postmortem radiographs revealed chronic, severe osteoarthritis spanning the proximal interphalangeal joint of the left hind fifth digit. Numerous coccobacilli within the joint were strongly positive on Brucella immunohistochemical labelling, and Brucella sp. was isolated in pure culture from this lesion. Sparse Brucella-immunopositive bacteria were also observed in the cytoplasm of a pulmonary vascular monocyte, and multifocal granulomas were observed in the spinal cord and liver on histopathology. Findings from biochemical characterization, 16S ribosomal DNA, and bp26 gene sequencing of the bacterial isolate were identical to those from marine-origin brucellae isolated from cetaceans and phocids. Although omp2a gene sequencing revealed 100% homology with marine Brucella spp. infecting pinnipeds, whales, and humans, omp2b gene sequences were identical only to pinniped-origin isolates. Multilocus sequence typing classified the sea otter isolate as ST26, a sequence type previously associated only with cetaceans. Our data suggest that the sea otter Brucella strain represents a novel marine lineage that is distinct from both Brucella pinnipedialis and Brucella ceti. Prior reports document the zoonotic potential of the marine brucellae. Isolation of Brucella sp. from a stranded sea otter highlights the importance of wearing personal protective equipment when handling sea otters and other marine mammals as part of wildlife conservation and rehabilitation efforts.

Demonstration of the SeptiStrand benthic microbial fuel cell powering a magnetometer for ship detection

Science.gov (United States)

Arias-Thode, Y. Meriah; Hsu, Lewis; Anderson, Greg; Babauta, Jerome; Fransham, Roy; Obraztsova, Anna; Tukeman, Gabriel; Chadwick, D. Bart

2017-07-01

The Navy has a need for monitoring conditions and gathering information in marine environments. Sensors can monitor and report environmental parameters and potential activities such as animal movements, ships, or personnel. However, there has to be a means to power these sensors. One promising enabling technology that has been shown to provide long-term power production in underwater environments is the benthic microbial fuel cells (BMFC). BMFCs are devices that generate energy by coupling bioanodes and biocathodes through an external energy harvester. Recent studies have demonstrated success for usage of BMFCs in powering small instruments and other devices on the seafloor over limited periods of time. In this effort, a seven-stranded BMFC linear array of 30 m was designed to power a seafloor magnetometer to detect passing ship movements through Pearl Harbor, Hawaii. The BMFC system was connected to a flyback energy harvesting circuit that charged the battery powering the magnetometer. The deployment was demonstrated the BMFC supplied power to the battery for approximately 38 days. This is the first large-scale demonstration system for usage of the SeptiStrand BMFC technology to power a relevant sensor.

The importance of becoming double-stranded: Innate immunity and the kinetic model of HIV-1 central plus strand synthesis

International Nuclear Information System (INIS)

Poeschla, Eric

2013-01-01

Central initiation of plus strand synthesis is a conserved feature of lentiviruses and certain other retroelements. This complication of the standard reverse transcription mechanism produces a transient “central DNA flap” in the viral cDNA, which has been proposed to mediate its subsequent nuclear import. This model has assumed that the important feature is the flapped DNA structure itself rather than the process that produces it. Recently, an alternative kinetic model was proposed. It posits that central plus strand synthesis functions to accelerate conversion to the double-stranded state, thereby helping HIV-1 to evade single-strand DNA-targeting antiviral restrictions such as APOBEC3 proteins, and perhaps to avoid innate immune sensor mechanisms. The model is consistent with evidence that lentiviruses must often synthesize their cDNAs when dNTP concentrations are limiting and with data linking reverse transcription and uncoating. There may be additional kinetic advantages for the artificial genomes of lentiviral gene therapy vectors. - Highlights: • Two main functional models for HIV central plus strand synthesis have been proposed. • In one, a transient central DNA flap in the viral cDNA mediates HIV-1 nuclear import. • In the other, multiple kinetic consequences are emphasized. • One is defense against APOBEC3G, which deaminates single-stranded DNA. • Future questions pertain to antiviral restriction, uncoating and nuclear import

Sustained UK marine observations. Where have we been? Where are we now? Where are we going?

Science.gov (United States)

Owens, Nicholas J P

2014-09-28

This introduction traces the earliest interaction of ancient humans with their marine environment, through marine explorations in the Middle Ages and Renaissance, to the development of early marine science in the Enlightenment. This sets the scene for how marine observations developed in the modern era and explains the status of today's marine observation networks. The paper concludes with an assessment of the future needs and constraints of sustained marine observation networks and suggests the lessons from a long history might be the key to the future. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Low-residue euthanasia of stranded mysticetes.

Science.gov (United States)

Harms, Craig A; McLellan, William A; Moore, Michael J; Barco, Susan G; Clarke, Elsburgh O; Thayer, Victoria G; Rowles, Teresa K

2014-01-01

Euthanasia of stranded large whales poses logistic, safety, pharmaceutical, delivery, public relations, and disposal challenges. Reasonable arguments may be made for allowing a stranded whale to expire naturally. However, slow cardiovascular collapse from gravitational effects outside of neutral buoyancy, often combined with severely debilitating conditions, motivate humane efforts to end the animal's suffering. The size of the animal and prevailing environmental conditions often pose safety concerns for stranding personnel, which take priority over other considerations. When considering chemical euthanasia, the size of the animal also necessitates large quantities of euthanasia agents. Drug residues are a concern for relay toxicity to scavengers, particularly for pentobarbital-containing euthanasia solutions. Pentobarbital is also an environmental concern because of its stability and long persistence in aquatic environments. We describe a euthanasia technique for stranded mysticetes using readily available, relatively inexpensive, preanesthetic and anesthetic drugs (midazolam, acepromazine, xylazine) followed by saturated KCl delivered via custom-made needles and a low-cost, basic, pressurized canister. This method provides effective euthanasia while moderating personnel exposure to hazardous situations and minimizing drug residues of concern for relay toxicity.

Rescuing policy in tourism network research

DEFF Research Database (Denmark)

Dredge, Dianne

2018-01-01

Networks provide a powerful lens to understand complex relational entanglements that are transforming social, economic and political life. Through a discussion of the various streams of network research in tourism, this paper argues that policy matters run across and throughout these strands....... Rather than arguing for increased interest in tourism policy network research as a separate subfield, the paper argues for deeper theoretical engagement with the policy dimension in tourism network research. Researchers adopting a network ontology could gain considerable insights and open up new lines...

A protozoal-associated epizootic impacting marine wildlife: mass-mortality of southern sea otters (Enhydra lutris nereis) due to Sarcocystis neurona infection.

Science.gov (United States)

Miller, Melissa A; Conrad, Patricia A; Harris, Michael; Hatfield, Brian; Langlois, Gregg; Jessup, David A; Magargal, Spencer L; Packham, Andrea E; Toy-Choutka, Sharon; Melli, Ann C; Murray, Michael A; Gulland, Frances M; Grigg, Michael E

2010-09-20

During April 2004, 40 sick and dead southern sea otters (Enhydra lutris nereis) were recovered over 18km of coastline near Morro Bay, California. This event represented the single largest monthly spike in mortality ever recorded during 30 years of southern sea otter stranding data collection. Because of the point-source nature of the event and clinical signs consistent with severe, acute neurological disease, exposure to a chemical or marine toxin was initially considered. However, detailed postmortem examinations revealed lesions consistent with an infectious etiology, and further investigation confirmed the protozoan parasite Sarcocystis neurona as the underlying cause. Tissues from 94% of examined otters were PCR-positive for S. neurona, based on DNA amplification and sequencing at the ITS-1 locus, and 100% of tested animals (n=14) had elevated IgM and IgG titers to S. neurona. Evidence to support the point-source character of this event include the striking spatial and temporal clustering of cases and detection of high concentrations of anti-S. neurona IgM in serum of stranded animals. Concurrent exposure to the marine biotoxin domoic acid may have enhanced susceptibility of affected otters to S. neurona and exacerbated the neurological signs exhibited by stranded animals. Other factors that may have contributed to the severity of this epizootic include a large rainstorm that preceded the event and an abundance of razor clams near local beaches, attracting numerous otters close to shore within the affected area. This is the first report of a localized epizootic in marine wildlife caused by apicomplexan protozoa.

An on-line tissue bank for marine mammals of the Mediterranean sea and adjacent waters

Directory of Open Access Journals (Sweden)

Cristina Ballarin

2006-03-01

Full Text Available Abstract This paper reports on the activities of the Mediterranean Tissue Bank for Marine Mammals, established in January 2002. The bank collects fragments of tissues sampled from marine mammals stranded along the Mediterranean coastline and distributes them to scientists working in the field. Tissues are a critical resource for biomedical and innovative research in anatomy, histo-pathology, genetics and toxicology, and the bank exploits the potentials of stranded animals to serve the scientific community of dolphin and whale investigators. Riassunto Una banca on line per i tessuti dei Mammiferi marini del Mediterraneo e dei mari limitrofi. Questo articolo presenta le attività della Banca per i tessuti dei Mammiferi Marini del Mediterraneo, istituita nel gennaio 2002. I tessuti sono una risorsa critica e innovativa per le ricerche biomediche in anatomia, istopatologia, genetica e tossicologia. La banca raccoglie campioni di tessuto dai mammiferi marini spiaggiati lungo le coste del Mediterraneo e li distribuisce ai ricercatori che lavorano nel settore.

Compliant lightweight non-invasive standalone “Marine Skin” tagging system

KAUST Repository

Nassar, Joanna M.; Khan, Sherjeel M.; Velling, Seneca J.; Diaz-Gaxiola, Andrea; Shaikh, Sohail F.; Geraldi, Nathan R.; Sevilla, Galo T.; Duarte, Carlos M.; Hussain, Muhammad Mustafa

2018-01-01

Current marine research primarily depends on weighty and invasive sensory equipment and telemetric network to understand the marine environment, including the diverse fauna it contains, as a function of animal behavior and size, as well as equipment

Current redistribution in cables made of insulated, soldered, or oxidized strands

International Nuclear Information System (INIS)

Turck, B.

1979-07-01

Current redistributions are compared in cables made of insulated strands, soldered, or oxidized strands and insulated strands with periodic joints. After discussing the different current redistributions in the cases of a rapidly changing current and a dc current, several particular situations are investigated: what happens if a strand is broken, or if a local normal zone appears that does not affect all the strands equally, the detection of this normal zone, and the influence of short circuits between strands

Madagascar's nascent locally managed marine area network ...

African Journals Online (AJOL)

Since 2004, the creation of locally managed marine areas (LMMAs) in Madagascar has exponentially increased, highlighting the need for improved information sharing between communities and between support organizations. Until recently, however, these LMMAs operated in relative isolation, with little communication or ...

Strand SPA & Konverentsikeskus

Index Scriptorium Estoniae

2008-01-01

Strand SPA & Konverentsikeskus on Pärnu suurim äri- ja konverentsiklientidele suunatud hotell, mis klientide seas on hinnatud just selle kompleksuse tõttu, kuna kõik, mida külaline vajab ja soovib, on olemas ühe katuse all

Reef-fish larval dispersal patterns validate no-take marine reserve network connectivity that links human communities

Science.gov (United States)

Abesamis, Rene A.; Saenz-Agudelo, Pablo; Berumen, Michael L.; Bode, Michael; Jadloc, Claro Renato L.; Solera, Leilani A.; Villanoy, Cesar L.; Bernardo, Lawrence Patrick C.; Alcala, Angel C.; Russ, Garry R.

2017-09-01

Networks of no-take marine reserves (NTMRs) are a widely advocated strategy for managing coral reefs. However, uncertainty about the strength of population connectivity between individual reefs and NTMRs through larval dispersal remains a major obstacle to effective network design. In this study, larval dispersal among NTMRs and fishing grounds in the Philippines was inferred by conducting genetic parentage analysis on a coral-reef fish ( Chaetodon vagabundus). Adult and juvenile fish were sampled intensively in an area encompassing approximately 90 km of coastline. Thirty-seven true parent-offspring pairs were accepted after screening 1978 juveniles against 1387 adults. The data showed all types of dispersal connections that may occur in NTMR networks, with assignments suggesting connectivity among NTMRs and fishing grounds ( n = 35) far outnumbering those indicating self-recruitment ( n = 2). Critically, half (51%) of the inferred occurrences of larval dispersal linked reefs managed by separate, independent municipalities and constituent villages, emphasising the need for nested collaborative management arrangements across management units to sustain NTMR networks. Larval dispersal appeared to be influenced by wind-driven seasonal reversals in the direction of surface currents. The best-fit larval dispersal kernel estimated from the parentage data predicted that 50% of larvae originating from a population would attempt to settle within 33 km, and 95% within 83 km. Mean larval dispersal distance was estimated to be 36.5 km. These results suggest that creating a network of closely spaced (less than a few tens of km apart) NTMRs can enhance recruitment for protected and fished populations throughout the NTMR network. The findings underscore major challenges for regional coral-reef management initiatives that must be addressed with priority: (1) strengthening management of NTMR networks across political or customary boundaries; and (2) achieving adequate population

Reef-fish larval dispersal patterns validate no-take marine reserve network connectivity that links human communities

KAUST Repository

Abesamis, Rene A.

2017-03-24

Networks of no-take marine reserves (NTMRs) are a widely advocated strategy for managing coral reefs. However, uncertainty about the strength of population connectivity between individual reefs and NTMRs through larval dispersal remains a major obstacle to effective network design. In this study, larval dispersal among NTMRs and fishing grounds in the Philippines was inferred by conducting genetic parentage analysis on a coral-reef fish (Chaetodon vagabundus). Adult and juvenile fish were sampled intensively in an area encompassing approximately 90 km of coastline. Thirty-seven true parent-offspring pairs were accepted after screening 1978 juveniles against 1387 adults. The data showed all types of dispersal connections that may occur in NTMR networks, with assignments suggesting connectivity among NTMRs and fishing grounds (n = 35) far outnumbering those indicating self-recruitment (n = 2). Critically, half (51%) of the inferred occurrences of larval dispersal linked reefs managed by separate, independent municipalities and constituent villages, emphasising the need for nested collaborative management arrangements across management units to sustain NTMR networks. Larval dispersal appeared to be influenced by wind-driven seasonal reversals in the direction of surface currents. The best-fit larval dispersal kernel estimated from the parentage data predicted that 50% of larvae originating from a population would attempt to settle within 33 km, and 95% within 83 km. Mean larval dispersal distance was estimated to be 36.5 km. These results suggest that creating a network of closely spaced (less than a few tens of km apart) NTMRs can enhance recruitment for protected and fished populations throughout the NTMR network. The findings underscore major challenges for regional coral-reef management initiatives that must be addressed with priority: (1) strengthening management of NTMR networks across political or customary boundaries; and (2) achieving adequate population

Machine Learning and Infrared Thermography for Fiber Orientation Assessment on Randomly-Oriented Strands Parts.

Science.gov (United States)

Fernandes, Henrique; Zhang, Hai; Figueiredo, Alisson; Malheiros, Fernando; Ignacio, Luis Henrique; Sfarra, Stefano; Ibarra-Castanedo, Clemente; Guimaraes, Gilmar; Maldague, Xavier

2018-01-19

The use of fiber reinforced materials such as randomly-oriented strands has grown in recent years, especially for manufacturing of aerospace composite structures. This growth is mainly due to their advantageous properties: they are lighter and more resistant to corrosion when compared to metals and are more easily shaped than continuous fiber composites. The resistance and stiffness of these materials are directly related to their fiber orientation. Thus, efficient approaches to assess their fiber orientation are in demand. In this paper, a non-destructive evaluation method is applied to assess the fiber orientation on laminates reinforced with randomly-oriented strands. More specifically, a method called pulsed thermal ellipsometry combined with an artificial neural network, a machine learning technique, is used in order to estimate the fiber orientation on the surface of inspected parts. Results showed that the method can be potentially used to inspect large areas with good accuracy and speed.

Development of strand burner for solid propellant burning rate studies

International Nuclear Information System (INIS)

Aziz, A; Mamat, R; Ali, W K Wan

2013-01-01

It is well-known that a strand burner is an apparatus that provides burning rate measurements of a solid propellant at an elevated pressure in order to obtain the burning characteristics of a propellant. This paper describes the facilities developed by author that was used in his studies. The burning rate characteristics of solid propellant have be evaluated over five different chamber pressures ranging from 1 atm to 31 atm using a strand burner. The strand burner has a mounting stand that allows the propellant strand to be mounted vertically. The strand was ignited electrically using hot wire, and the burning time was recorded by electronic timer. Wire technique was used to measure the burning rate. Preliminary results from these techniques are presented. This study shows that the strand burner can be used on propellant strands to obtain accurate low pressure burning rate data

Double-Stranded Peptide Nucleic Acids

DEFF Research Database (Denmark)

2001-01-01

A novel class of compounds, known as peptide nucleic acids, form double-stranded structures with one another and with ssDNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker.......A novel class of compounds, known as peptide nucleic acids, form double-stranded structures with one another and with ssDNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

The (not so) immortal strand hypothesis.

Science.gov (United States)

Tomasetti, Cristian; Bozic, Ivana

2015-03-01

Non-random segregation of DNA strands during stem cell replication has been proposed as a mechanism to minimize accumulated genetic errors in stem cells of rapidly dividing tissues. According to this hypothesis, an "immortal" DNA strand is passed to the stem cell daughter and not the more differentiated cell, keeping the stem cell lineage replication error-free. After it was introduced, experimental evidence both in favor and against the hypothesis has been presented. Using a novel methodology that utilizes cancer sequencing data we are able to estimate the rate of accumulation of mutations in healthy stem cells of the colon, blood and head and neck tissues. We find that in these tissues mutations in stem cells accumulate at rates strikingly similar to those expected without the protection from the immortal strand mechanism. Utilizing an approach that is fundamentally different from previous efforts to confirm or refute the immortal strand hypothesis, we provide evidence against non-random segregation of DNA during stem cell replication. Our results strongly suggest that parental DNA is passed randomly to stem cell daughters and provides new insight into the mechanism of DNA replication in stem cells. Copyright © 2015. Published by Elsevier B.V.

Madagascar's nascent locally managed marine area network

African Journals Online (AJOL)

communication, raise the profile and expand the use of the ... community - led approaches to conservation in Madagascar and ... Fishing communities have been managing marine resources in ... munities are finding that once abundant resources are dwin- .... per closure and lead to an enhancement in catch per unit effort.

Fatal Canine Intoxications Linked to the Presence of Saxitoxins in Stranded Marine Organisms Following Winter Storm Activity

Directory of Open Access Journals (Sweden)

Andrew D. Turner

2018-02-01

Full Text Available At the start of 2018, multiple incidents of dog illnesses were reported following consumption of marine species washed up onto the beaches of eastern England after winter storms. Over a two-week period, nine confirmed illnesses including two canine deaths were recorded. Symptoms in the affected dogs included sickness, loss of motor control, and muscle paralysis. Samples of flatfish, starfish, and crab from the beaches in the affected areas were analysed for a suite of naturally occurring marine neurotoxins of dinoflagellate origin. Toxins causing paralytic shellfish poisoning (PSP were detected and quantified using two independent chemical testing methods in samples of all three marine types, with concentrations over 14,000 µg saxitoxin (STX eq/kg found in one starfish sample. Further evidence for PSP intoxication of the dogs was obtained with the positive identification of PSP toxins in a vomited crab sample from one deceased dog and in gastrointestinal samples collected post mortem from a second affected dog. Together, this is the first report providing evidence of starfish being implicated in a PSP intoxication case and the first report of PSP in canines.

Marine data security based on blockchain technology

Science.gov (United States)

Yang, Zhao; Xie, Weiwei; Huang, Lei; Wei, Zhiqiang

2018-03-01

With the development of marine observation technology and network technology, the volume of marine data growing rapidly. This brings new challenges for data storage and transmission. How to protect data security of marine big data has become an urgent problem. The traditional information security methods’ characteristic is centralization. These technologies cannot provide whole process protection, e.g., data storage, data management and application of data. The blockchain technology is a novel technology, which can keep the data security and reliability by using decentralized methodology. It has aroused wide interest in the financial field. In this paper, we describe the concept, characteristics and key technologies of blockchain technology and introduce it into the field of marine data security.

DNA strand breakage by 125I-decay in oligoDNA

International Nuclear Information System (INIS)

Lobachevsky, P.; Martin, R.F.

1996-01-01

Full text: A double-stranded oligodeoxynucleotide containing 125 I-dC in a defined location, with 5'- or 3'- 32 P-end-labelling of either strand, was used to investigate DNA strand breakage resulting from 125 I decay. Samples of the 32 P-end-labelled and 125 I-dC containing oligoDNA were incubated in 20 mM phosphate buffer (PB), or PB + 2 M dimethylsulphoxide (DMSO) at 4 deg during 18-20 days. The 32 P-end-labelled DNA fragments produced by 125 I decays were separated on denaturing polyacrylamide gels, and the 3P activity in each fragment was determined by scintillation counting after elution from the gel. The fragment size distribution was then converted to a distribution of single stranded break probabilities at each nucleotide position. The results indicate that each 125 I decay event produces at least one break in the 125 I-dC containing strand, and causes breakage of the opposite strand in 75-80% of events. Thus, the double stranded break is produced by 125 I decay with probability ∼0.8. Most of single stranded breaks (around 90%) occurred within 5-6 nucleotides of the 125 I-dC, however DNA breaks were detected up to 18-20 nucleotides from the decay site. The average numbers of single stranded breaks per decay are 3.7 (PB) and 3.3 (PB+DMSO) in 125 I-dC containing strand, and 1.5 (PB) and 1.3 (PB+DMSO) in the opposite strand. Deconvolution of strand break probabilities as a function of separation from the 125 I, in terms of both distance (to target deoxyribosyl carbon atoms, in B-DNA) and nucleotide number, show that the latter is an important parameter for the shorter-range damage. This could indicate a role for attenuation/dissipation of damage through the stacked bases. In summary, the results represent a much more extensive set of data than available from earlier experiments on DNA breakage from l25 I-decay, and may provide new mechanistic insights

Tissue strands as "bioink" for scale-up organ printing.

Science.gov (United States)

Yu, Yin; Ozbolat, Ibrahim T

2014-01-01

Organ printing, takes tissue spheroids as building blocks together with additive manufacturing technique to engineer tissue or organ replacement parts. Although a wide array of cell aggregation techniques has been investigated, and gained noticeable success, the application of tissue spheroids for scale-up tissue fabrication is still worth investigation. In this paper, we introduce a new micro-fabrication technique to create tissue strands at the scale of 500-700μm as a "bioink" for future robotic tissue printing. Printable alginate micro-conduits are used as semi-permeable capsules for tissue strand fabrication. Mouse insulinoma beta TC3 cell tissue strands were formed upon 4 days post fabrication with reasonable mechanical strength, high cell viability close to 90%, and tissue specific markers expression. Fusion was readily observed between strands when placing them together as early as 24h. Also, tissue strands were deposited with human umbilical vein smooth muscle cells (HUVSMCs) vascular conduits together to fabricated miniature pancreatic tissue analog. Our study provided a novel technique using tissue strands as "bioink" for scale-up bioprinting of tissues or organs.

A methodology to identify stranded generation facilities and estimate stranded costs for Louisiana's electric utility industry

Science.gov (United States)

Cope, Robert Frank, III

1998-12-01

The electric utility industry in the United States is currently experiencing a new and different type of growing pain. It is the pain of having to restructure itself into a competitive business. Many industry experts are trying to explain how the nation as a whole, as well as individual states, will implement restructuring and handle its numerous "transition problems." One significant transition problem for federal and state regulators rests with determining a utility's stranded costs. Stranded generation facilities are assets which would be uneconomic in a competitive environment or costs for assets whose regulated book value is greater than market value. At issue is the methodology which will be used to estimate stranded costs. The two primary methods are known as "Top-Down" and "Bottom-Up." The "Top-Down" approach simply determines the present value of the losses in revenue as the market price for electricity changes over a period of time into the future. The problem with this approach is that it does not take into account technical issues associated with the generation and wheeling of electricity. The "Bottom-Up" approach computes the present value of specific strandable generation facilities and compares the resulting valuations with their historical costs. It is regarded as a detailed and difficult, but more precise, approach to identifying stranded assets and their associated costs. This dissertation develops a "Bottom-Up" quantitative, optimization-based approach to electric power wheeling within the state of Louisiana. It optimally evaluates all production capabilities and coordinates the movement of bulk power through transmission interconnections of competing companies in and around the state. Sensitivity analysis to this approach is performed by varying seasonal consumer demand, electric power imports, and transmission inter-connection cost parameters. Generation facility economic dispatch and transmission interconnection bulk power transfers, specific

Green Marine: An environmental program to establish sustainability in marine transportation.

Science.gov (United States)

Walker, Tony R

2016-04-15

European maritime companies have adopted programs to limit operational impacts on the environment. For maritime companies in North America, the Green Marine Environmental Program (GMEP) offers a framework to establish and reduce environmental footprints. Green Marine (GM) participants demonstrate annual improvements of specific environmental performance indicators (e.g., reductions in air pollution emissions) to maintain certification. Participants complete annual self-evaluations with results determining rankings for performance indicators on a 1-to-5 scale. Self-evaluations are independently verified every two years to ensure rigor and individual results are made publicly available annually to achieve transparency. GM benefits the marine industry across North America by encouraging sustainable development initiatives. GM's credibility is reflected through a diverse network of environmental groups and government agencies that endorse and help shape the program. Merits of this relatively new maritime certification (not previously described in the academic literature), are discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Long range inland-coastal networks during the Late Magdalenian: evidence for individual acquisition of marine resources at Andernach-Martinsberg, German Central Rhineland.

Science.gov (United States)

Langley, Michelle C; Street, Martin

2013-05-01

Recent re-examination of the osseous material assemblage from Andernach-Martinsberg, Central Rhineland, has resulted in the identification of an implement manufactured from cetacean bone (probably whale). Argued to be the proximal half of a foreshaft, this artefact is not only one of few such projectile elements to be identified in Magdalenian deposits in northern Europe, but also demonstrates that the exploitation of marine raw materials for use in manufacturing projectile elements is not restricted to southern France, instead extending to at least inland Germany. Additionally, in conjunction with the appearance of marine molluscs and engravings of seals at Andernach, it can now be forcefully argued that this region formed part of an inland-coastal network during the Late Magdalenian and allows us for the first time to suggest that we can identify the movements of individuals transporting valued marine sourced raw materials and their personal experiences across this vast region. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Effect of Twist Pitch in the Strands on the Saturation and Losses in the Nb3Sn Strands for the ITER TF CICC

International Nuclear Information System (INIS)

Martovetsky, N.N.

2007-01-01

ITER TF coils will see a significant longitudinal magnetic field in the event of the plasma disruption. This abrupt change of magnetic fields results in the appearance of an additional electrical field in the strands. The mechanism of this electrical field is the induced currents that expel the flux from the strands. This effect was known since the late 1970's [1-3] and most of the details necessary for the analyses given in this report are presented in [4]. Let's assume for simplicity a zero transport current in the strand. When a longitudinal pulsed field is applied, the outer filaments will carry an induced current repelling the change of flux. The current density of this current is 'critical' in the simplification of Bean's critical state model, where superconducting transition is represented as j=j c at any non-zero electrical field and zero where the electrical field has not penetrated. In reality, since the current density is roughly logarithmic with the electrical field, E=E c *exp[(j-j c )/jo], Bean's model is just a simplification, and current density is slightly nonuniform in the outer filament and more so for the interior strands. The inner portion of the filaments will carry a current of the opposite sign. Even in the Bean's model it is not uniform, but the assumption that it is uniform and less than critical simplifies mathematics significantly and does not deviate far from the real current density distribution. In certain circumstances, the average electrical field in the strands will be high enough to exceed the take-off electrical field averaged across the cross section. In this case, the multifilamentary strand will become unstable and will experience transition to the normal state. With zero transport current, it will eventually recover, of course. This phenomenon is analogous to the flux jump. If the strand carries a transport current, the situation becomes more complicated. If it goes unstable and the transport current is higher than the

In vitro Assays for Eukaryotic Leading/Lagging Strand DNA Replication.

Science.gov (United States)

Schauer, Grant; Finkelstein, Jeff; O'Donnell, Mike

2017-09-20

The eukaryotic replisome is a multiprotein complex that duplicates DNA. The replisome is sculpted to couple continuous leading strand synthesis with discontinuous lagging strand synthesis, primarily carried out by DNA polymerases ε and δ, respectively, along with helicases, polymerase α-primase, DNA sliding clamps, clamp loaders and many other proteins. We have previously established the mechanisms by which the polymerases ε and δ are targeted to their 'correct' strands, as well as quality control mechanisms that evict polymerases when they associate with an 'incorrect' strand. Here, we provide a practical guide to differentially assay leading and lagging strand replication in vitro using pure proteins.

Machine Learning and Infrared Thermography for Fiber Orientation Assessment on Randomly-Oriented Strands Parts

Science.gov (United States)

Maldague, Xavier

2018-01-01

The use of fiber reinforced materials such as randomly-oriented strands has grown in recent years, especially for manufacturing of aerospace composite structures. This growth is mainly due to their advantageous properties: they are lighter and more resistant to corrosion when compared to metals and are more easily shaped than continuous fiber composites. The resistance and stiffness of these materials are directly related to their fiber orientation. Thus, efficient approaches to assess their fiber orientation are in demand. In this paper, a non-destructive evaluation method is applied to assess the fiber orientation on laminates reinforced with randomly-oriented strands. More specifically, a method called pulsed thermal ellipsometry combined with an artificial neural network, a machine learning technique, is used in order to estimate the fiber orientation on the surface of inspected parts. Results showed that the method can be potentially used to inspect large areas with good accuracy and speed. PMID:29351240

Fragmentation in DNA double-strand breaks

International Nuclear Information System (INIS)

Wei Zhiyong; Suzhou Univ., Suzhou; Zhang Lihui; Li Ming; Fan Wo; Xu Yujie

2005-01-01

DNA double strand breaks are important lesions induced by irradiations. Random breakage model or quantification supported by this concept is suitable to analyze DNA double strand break data induced by low LET radiation, but deviation from random breakage model is more evident in high LET radiation data analysis. In this work we develop a new method, statistical fragmentation model, to analyze the fragmentation process of DNA double strand breaks. After charged particles enter the biological cell, they produce ionizations along their tracks, and transfer their energies to the cells and break the cellular DNA strands into fragments. The probable distribution of the fragments is obtained under the condition in which the entropy is maximum. Under the approximation E≅E 0 + E 1 l + E 2 l 2 , the distribution functions are obtained as exp(αl + βl 2 ). There are two components, the one proportional to exp(βl 2 ), mainly contributes to the low mass fragment yields, the other component, proportional to exp(αl), decreases slowly as the mass of the fragments increases. Numerical solution of the constraint equations provides parameters α and β. Experimental data, especially when the energy deposition is higher, support the statistical fragmentation model. (authors)

A review on existing OSSEs and their implications on European marine observation requirements

Science.gov (United States)

She, Jun

2017-04-01

Marine observations are essential for understanding marine processes and improving the forecast quality, they are also expensive. It has always been an important issue to optimize sampling schemes of marine observational networks so that the value of marine observations can be maximized and the cost can be lowered. Ocean System Simulation Experiment (OSSE) is an efficient tool in assessing impacts of proposed future sampling schemes on reconstructing and forecasting the ocean and ecosystem conditions. In this study existing OSSE research results from EU projects (such as JERICO, OPEC, SANGOMA, E-AIMS and AtlantOS), institutional studies and review papers are collected and analyzed, according to regions (Arctic, Baltic, N. Atlantic, Mediterranean Sea and Black Sea) and instruments/variables. The preliminary results show that significant gaps for OSSEs in regions and instruments. Among the existing OSSEs, Argo (Bio-Argo and Deep See Argo), gliders and ferrybox are the most often investigated instruments. Although many of the OSSEs are dedicated for very specific monitoring strategies and not sufficiently comprehensive for making solid recommendations for optimizing the existing networks, the detailed findings for future marine observation requirements from the OSSEs will be summarized in the presentation. Recommendations for systematic OSSEs for optimizing European marine observation networks are also given.

Marine Corps Private Cloud Computing Environment Strategy

Science.gov (United States)

2012-05-15

leveraging economies of scale through the MCEITS PCCE, the Marine Corps will measure consumed IT resources more effectively, increase or decrease...flexible broad network access, resource pooling, elastic provisioning and measured services. By leveraging economies of scale the Marine Corps will be able...IaaS SaaS / IaaS 1 1 LCE I ACE Dets I I I I ------------------~ GIG / CJ Internet Security Boundary MCEN I DISN r :------------------ MCEN

Manufacture of Strand Board Bonded with Disposal Expanded Polystyrene as Binder

OpenAIRE

Hermawan, Andi; Ohuchi, Takeshi; Fujimoto, Noboru; 大内, 毅; 藤本, 登留

2010-01-01

The objective of this study was to evaluate the physical and mechanical properties of strand board bonded with disposal expanded polystyrene (EPS) as binder. The strand board was manufactured using strand made from Douglas-fir beams selected from construction scrap wood. The strands were oriented, and two types of three-layer (face-core-face) strand board were manufactured: one in which the board bounded with only disposal EPS (P board), and the other in which the board bonded with disposal...

Four-Strand Core Suture Improves Flexor Tendon Repair Compared to Two-Strand Technique in a Rabbit Model

Directory of Open Access Journals (Sweden)

Alice Wichelhaus

2016-01-01

Full Text Available Introduction. This study was designed to investigate the influence of the amount of suture material on the formation of peritendinous adhesions of intrasynovial flexor tendon repairs. Materials and Methods. In 14 rabbits, the flexor tendons of the third and the fourth digit of the right hind leg were cut and repaired using a 2- or 4-strand core suture technique. The repaired tendons were harvested after three and eight weeks. The range of motion of the affected toes was measured and the tendons were processed histologically. The distance between the transected tendon ends, the changes in the peritendinous space, and cellular and extracellular inflammatory reaction were quantified by different staining. Results. A 4-strand core suture resulted in significantly less gap formation. The 2-strand core suture showed a tendency to less adhesion formation. Doubling of the intratendinous suture material was accompanied by an initial increase in leukocyte infiltration and showed a greater amount of formation of myofibroblasts. From the third to the eighth week after flexor tendon repair, both the cellular and the extracellular inflammation decreased significantly. Conclusion. A 4-strand core suture repair leads to a significantly better tendon healing process with less diastasis between the sutured tendon ends despite initially pronounced inflammatory response.

Control of DNA strand displacement kinetics using toehold exchange.

Science.gov (United States)

Zhang, David Yu; Winfree, Erik

2009-12-02

DNA is increasingly being used as the engineering material of choice for the construction of nanoscale circuits, structures, and motors. Many of these enzyme-free constructions function by DNA strand displacement reactions. The kinetics of strand displacement can be modulated by toeholds, short single-stranded segments of DNA that colocalize reactant DNA molecules. Recently, the toehold exchange process was introduced as a method for designing fast and reversible strand displacement reactions. Here, we characterize the kinetics of DNA toehold exchange and model it as a three-step process. This model is simple and quantitatively predicts the kinetics of 85 different strand displacement reactions from the DNA sequences. Furthermore, we use toehold exchange to construct a simple catalytic reaction. This work improves the understanding of the kinetics of nucleic acid reactions and will be useful in the rational design of dynamic DNA and RNA circuits and nanodevices.

Electro-mechanical behaviors of composite superconducting strand with filament breakage

International Nuclear Information System (INIS)

Wang, Xu; Gao, Yuanwen; Zhou, Youhe

2016-01-01

Highlights: • The electromechanical behaviors of the superconducting (SC) strand are investigated. • A 3D FEM model for bending behaviors and electric properties of strand is developed. • The influence of breakage of filaments on the critical current of SC strand is calculated. • The impact of current transfer length on the electric properties of SC strand is discussed. - Abstract: The bending behaviors of superconducting strand with typical multi-filament twist configuration are investigated based on a three-dimensional finite element method (FEM) model, named as the Multi-filament twist model, of the strand. In this 3D FEM model, the impacts of initial thermal residual stress, filament-breakage and its evaluation are taken into accounts. The mechanical responses of the strand under bending load are studied with the factors taken into consideration one by one. The distribution of the damage of the filaments and its evolution and the movement of the neutral axis caused by it are studied and displayed in detail. Besides, taking the advantages of the Multi-filament twist model, the normalized critical current of the strand under bending load is also calculated based on the invariant temperature and field strain functions. In addition, the non-negligible influences of the pitch length of the filaments on both the mechanical behaviors and the normalized critical current are discussed. The stress-strain characteristics of the strand under tensile load and the normalized critical current of it under axial and bending loads resulting from the Multi-filament twist model show good agreement with the experimental data.

Electro-mechanical behaviors of composite superconducting strand with filament breakage

Energy Technology Data Exchange (ETDEWEB)

Wang, Xu [Key Laboratory of Mechanics on Environment and Disaster in Western China, The Ministry of Education of China, Lanzhou, Gansu 730000 (China); Department of Mechanics and Engineering Science, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000 (China); Gao, Yuanwen, E-mail: ywgao@lzu.edu.cn [Key Laboratory of Mechanics on Environment and Disaster in Western China, The Ministry of Education of China, Lanzhou, Gansu 730000 (China); Department of Mechanics and Engineering Science, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000 (China); Zhou, Youhe [Key Laboratory of Mechanics on Environment and Disaster in Western China, The Ministry of Education of China, Lanzhou, Gansu 730000 (China); Department of Mechanics and Engineering Science, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu 730000 (China)

2016-10-15

Highlights: • The electromechanical behaviors of the superconducting (SC) strand are investigated. • A 3D FEM model for bending behaviors and electric properties of strand is developed. • The influence of breakage of filaments on the critical current of SC strand is calculated. • The impact of current transfer length on the electric properties of SC strand is discussed. - Abstract: The bending behaviors of superconducting strand with typical multi-filament twist configuration are investigated based on a three-dimensional finite element method (FEM) model, named as the Multi-filament twist model, of the strand. In this 3D FEM model, the impacts of initial thermal residual stress, filament-breakage and its evaluation are taken into accounts. The mechanical responses of the strand under bending load are studied with the factors taken into consideration one by one. The distribution of the damage of the filaments and its evolution and the movement of the neutral axis caused by it are studied and displayed in detail. Besides, taking the advantages of the Multi-filament twist model, the normalized critical current of the strand under bending load is also calculated based on the invariant temperature and field strain functions. In addition, the non-negligible influences of the pitch length of the filaments on both the mechanical behaviors and the normalized critical current are discussed. The stress-strain characteristics of the strand under tensile load and the normalized critical current of it under axial and bending loads resulting from the Multi-filament twist model show good agreement with the experimental data.

Double-Strand DNA Break Repair in Mycobacteria.

Science.gov (United States)

Glickman, Michael S

2014-10-01

Discontinuity of both strands of the chromosome is a lethal event in all living organisms because it compromises chromosome replication. As such, a diversity of DNA repair systems has evolved to repair double-strand DNA breaks (DSBs). In part, this diversity of DSB repair systems has evolved to repair breaks that arise in diverse physiologic circumstances or sequence contexts, including cellular states of nonreplication or breaks that arise between repeats. Mycobacteria elaborate a set of three genetically distinct DNA repair pathways: homologous recombination, nonhomologous end joining, and single-strand annealing. As such, mycobacterial DSB repair diverges substantially from the standard model of prokaryotic DSB repair and represents an attractive new model system. In addition, the presence in mycobacteria of a DSB repair system that can repair DSBs in nonreplicating cells (nonhomologous end joining) or when DSBs arise between repeats (single-strand annealing) has clear potential relevance to Mycobacterium tuberculosis pathogenesis, although the exact role of these systems in M. tuberculosis pathogenesis is still being elucidated. In this article we will review the genetics of mycobacterial DSB repair systems, focusing on recent insights.

The (not so) Immortal Strand Hypothesis

OpenAIRE

Tomasetti, Cristian; Bozic, Ivana

2015-01-01

Background: Non-random segregation of DNA strands during stem cell replication has been proposed as a mechanism to minimize accumulated genetic errors in stem cells of rapidly dividing tissues. According to this hypothesis, an “immortal” DNA strand is passed to the stem cell daughter and not the more differentiated cell, keeping the stem cell lineage replication error-free. After it was introduced, experimental evidence both in favor and against the hypothesis has been presented. Principal...

A new cable-in-conduit conductor magnet with insulated strands

International Nuclear Information System (INIS)

Yamaguchi, Satarou; Yamamoto, Junya; Motojima, Osamu.

1995-09-01

Many studies have used cable-in-conduit conductor (CICC) coils in trying to develop an AC superconducting magnet because of its enormous potential if AC losses were low and insulation voltage was high. The strands in the most recent CICC magnets are coated with chromium or another metal with high electrical resistance to order to induce current re-distribution among the strands and to avoid a quench caused by a current imbalance. Current re-distribution is highly complex and very difficult to analyze because the conditions of the strand surfaces and the contact areas vary greatly with the operation of the conductor. If, however, the cable currents were well-balanced, insulating the strands would be the best way to reduce AC losses. We propose a new CICC magnet structure featuring a current lead that balances the strand currents via its resistance. Having calculated current balances, we find that strand currents are well within the present parameters for nuclear fusion experiments and superconducting magnet energy storages. (author)

The risk of stranded assets for utilities in Canada

International Nuclear Information System (INIS)

Schroeder, W.

1998-01-01

The problems of dealing with stranded assets in Canada and the United States were discussed. Compared to the United States, the risk associated with stranded assets for utilities in Canada was considered to be relatively low because of the following factors: (1) low variable cost, (2) isolation, (3) lack of transmission interconnection capacity, (4) lack of tight synchronization in North America, (5) the likelihood of an increase in natural gas prices, (6) the absence of jurisdictional disputes such as FERC versus the states, (7) social considerations, (8) the learning curve, (9) politics, (10) weak balance sheets, (11) relatively low electricity prices, (12) the weak Canadian dollar, and (13) the possibility of refinancing at lower interest rates. Ontario Hydro, New Brunswick and Nova Scotia Power are the three Canadian utilities that may have stranded costs. For Ontario Hydro and New Brunswick Power the stranded costs would be related to nuclear generator problems, whereas for Nova Scotia Power, the stranded costs would be related to the thermal generating base, the threat from Sable Island Gas and the changing tax structure of the utility. Some other reasons why stranded assets could be created in Canada would include low variable costs and high fixed costs, over capacity of at least 30 per cent in generation, limited domestic energy growth, competitive threat from gas, reliability and safety of nuclear plants, and technology change. Five factors in terms of which stranded assets can be expressed are: (1) variable cost definition, (2) total cost definition, (3) operating profit definition, (4) wide geographic definition, and (5) free market definition. In calculating stranded assets, the number of years over which the assets are recovered and the discount rate are considered to be key factors. 26 tabs

IPANEMA 6 Initiative Partenariale Nationale pour l'emergence des Energies Marines (National partnership initiative for the emergence of marine energies). Progress report

International Nuclear Information System (INIS)

2009-01-01

The IPANEMA initiative is a work group built up by public and private actors. Its objectives are the development of scientific and industrial sector dedicated to marine energies, to set up a coordinated network of French actors involved in marine energies, to develop offshore test sites adapted to different technologies aimed at the exploitation of marine energies, and to facilitate the development of demonstrators. After a presentation of the participants, of the overall project governance and of projects which currently are being developed in France, this report makes and discusses some propositions to reach the above-mentioned objectives. It also outlines necessary transversal actions to anticipate the deployment of marine energies

Monitoring the abundance of plastic debris in the marine environment.

Science.gov (United States)

Ryan, Peter G; Moore, Charles J; van Franeker, Jan A; Moloney, Coleen L

2009-07-27

Plastic debris has significant environmental and economic impacts in marine systems. Monitoring is crucial to assess the efficacy of measures implemented to reduce the abundance of plastic debris, but it is complicated by large spatial and temporal heterogeneity in the amounts of plastic debris and by our limited understanding of the pathways followed by plastic debris and its long-term fate. To date, most monitoring has focused on beach surveys of stranded plastics and other litter. Infrequent surveys of the standing stock of litter on beaches provide crude estimates of debris types and abundance, but are biased by differential removal of litter items by beachcombing, cleanups and beach dynamics. Monitoring the accumulation of stranded debris provides an index of debris trends in adjacent waters, but is costly to undertake. At-sea sampling requires large sample sizes for statistical power to detect changes in abundance, given the high spatial and temporal heterogeneity. Another approach is to monitor the impacts of plastics. Seabirds and other marine organisms that accumulate plastics in their stomachs offer a cost-effective way to monitor the abundance and composition of small plastic litter. Changes in entanglement rates are harder to interpret, as they are sensitive to changes in population sizes of affected species. Monitoring waste disposal on ships and plastic debris levels in rivers and storm-water runoff is useful because it identifies the main sources of plastic debris entering the sea and can direct mitigation efforts. Different monitoring approaches are required to answer different questions, but attempts should be made to standardize approaches internationally.

Equilibrious Strand Exchange Promoted by DNA Conformational Switching

Science.gov (United States)

Wu, Zhiguo; Xie, Xiao; Li, Puzhen; Zhao, Jiayi; Huang, Lili; Zhou, Xiang

2013-01-01

Most of DNA strand exchange reactions in vitro are based on toehold strategy which is generally nonequilibrium, and intracellular strand exchange mediated by proteins shows little sequence specificity. Herein, a new strand exchange promoted by equilibrious DNA conformational switching is verified. Duplexes containing c-myc sequence which is potentially converted into G-quadruplex are designed in this strategy. The dynamic equilibrium between duplex and G4-DNA is response to the specific exchange of homologous single-stranded DNA (ssDNA). The SER is enzyme free and sequence specific. No ATP is needed and the displaced ssDNAs are identical to the homologous ssDNAs. The SER products and exchange kenetics are analyzed by PAGE and the RecA mediated SER is performed as the contrast. This SER is a new feature of G4-DNAs and a novel strategy to utilize the dynamic equilibrium of DNA conformations.

Radiation induced strand breaks and time scale for repair of broken strands in superinfecting phage lambda DNA in Escherichia coli lysogenic for lambda

International Nuclear Information System (INIS)

Johansen, I.; Boye, E.; Brustad, T.

1975-01-01

The production of the first radiation induced break in covalent lambda DNA molecules in pol + and pol A 1 lysogenic host cells was measured after exposure to electrons from a linear accelerator and transfer to alkaline detergent within 100 ms from the onset of irradiation. The results revealed the presence of an oxygen effect in DNA strand breakage. In both pol + and pol A 1 host cells the rate of production in nitrogen was 1.2x10 -12 DNA single strand breaks per rad per dalton as compared to 5x10 -12 in oxygen. The yields of strand breaks in lambda DNA in pol + host cells under oxygenated or anoxic conditions are independent of whether the cells are irradiated in buffer at room temperature, in buffer at ice temperature, or in growth medium at 37 0 C. These results indicate that enzymic repair of DNA strand breaks before analysis is insignificant in these experiments. The presence of an oxygen effect in DNA strand breakage under these conditions suggest that an actual difference exists between initial number of breaks produced in nitrogen and in oxygen. The kinetics of rejoining of broken molecules under optimal growth conditions was measured by incubating the irradiated host cells prior to lysis. In pol + host cells 50% of the lambda DNA molecules broken in presence of oxygen are rejoined within 10 to 20 seconds of incubation. A significantly lower recovery is seen in pol + host cells after irradiation in nitrogen. The rejoining of broken lambda DNA strands in pol A 1 host cells is impaired after irradiation in presence of oxygen as well as under anoxia. These results show that DNA polymerase I is needed for the rapid rejoining of radiation induced strand breaks in the DNA, and that oxygen promoted strand breaks are more easily rejoined than are those produced in nitrogen. (author)

Induction of DNA strand breaks in 14C-labelled cells

International Nuclear Information System (INIS)

Sundell-Bergman, S.; Johanson, K.J.

1979-01-01

Chinese hamster cells grown in vitro were labelled with 14 C-thymidine for 18 hours and after 3 hours in non-radioactive medium they were stored at 0 0 C for various periods ( 1 to 12 hours). During this treatment a number of DNA strand breaks were induced by 14 C decay which were not repaired at 0 0 C. The number of DNA strand breaks was determined using the DNA unwinding technique. At 0.5-1 dpm per cell a detectable number of DNA strand breaks were found. Treatment for six hours (1 dpm per cell) reduced the percentage of double-stranded DNA from 80 to 70%, corresponding to about 750 DNA strand breaks per cell. The rejoining of DNA strand breaks was studied after treatment for 12 hours at 0 0 C followed by incubation of the cells for various periods at 37 0 C. Most of the DNA strand breaks induced by 14 C decay at 0 0 C were repaired after incubation at 37 0 C for 15 minutes. Assuming an absorbed dose of 1.8 mGy per 14 C decay to the cell nucleus an RBE value close to 1 was found for internal irradiation from 14 C decay as compared with 60 Co-gamma irradiation. (author)

New views on strand asymmetry in insect mitochondrial genomes.

Directory of Open Access Journals (Sweden)

Shu-Jun Wei

Full Text Available Strand asymmetry in nucleotide composition is a remarkable feature of animal mitochondrial genomes. Understanding the mutation processes that shape strand asymmetry is essential for comprehensive knowledge of genome evolution, demographical population history and accurate phylogenetic inference. Previous studies found that the relative contributions of different substitution types to strand asymmetry are associated with replication alone or both replication and transcription. However, the relative contributions of replication and transcription to strand asymmetry remain unclear. Here we conducted a broad survey of strand asymmetry across 120 insect mitochondrial genomes, with special reference to the correlation between the signs of skew values and replication orientation/gene direction. The results show that the sign of GC skew on entire mitochondrial genomes is reversed in all species of three distantly related families of insects, Philopteridae (Phthiraptera, Aleyrodidae (Hemiptera and Braconidae (Hymenoptera; the replication-related elements in the A+T-rich regions of these species are inverted, confirming that reversal of strand asymmetry (GC skew was caused by inversion of replication origin; and finally, the sign of GC skew value is associated with replication orientation but not with gene direction, while that of AT skew value varies with gene direction, replication and codon positions used in analyses. These findings show that deaminations during replication and other mutations contribute more than selection on amino acid sequences to strand compositions of G and C, and that the replication process has a stronger affect on A and T content than does transcription. Our results may contribute to genome-wide studies of replication and transcription mechanisms.

Getting Frustrated: Modelling Emotion Contagion in Stranded Passengers

NARCIS (Netherlands)

van der Wal, C. Natalie; Couwenberg, Maik; Bosse, T.

2017-01-01

Train passengers can get stranded due to a variety of events, such as a delay, technical malfunctioning or a natural disaster. Stranded passengers can get frustrated, which could escalate in misbehaviours. Examples are verbal and physical violence or dangerous behaviours such as opening emergency

Time-dependent fermentation control strategies for enhancing synthesis of marine bacteriocin 1701 using artificial neural network and genetic algorithm.

Science.gov (United States)

Peng, Jiansheng; Meng, Fanmei; Ai, Yuncan

2013-06-01

The artificial neural network (ANN) and genetic algorithm (GA) were combined to optimize the fermentation process for enhancing production of marine bacteriocin 1701 in a 5-L-stirred-tank. Fermentation time, pH value, dissolved oxygen level, temperature and turbidity were used to construct a "5-10-1" ANN topology to identify the nonlinear relationship between fermentation parameters and the antibiotic effects (shown as in inhibition diameters) of bacteriocin 1701. The predicted values by the trained ANN model were coincided with the observed ones (the coefficient of R(2) was greater than 0.95). As the fermentation time was brought in as one of the ANN input nodes, fermentation parameters could be optimized by stages through GA, and an optimal fermentation process control trajectory was created. The production of marine bacteriocin 1701 was significantly improved by 26% under the guidance of fermentation control trajectory that was optimized by using of combined ANN-GA method. Copyright © 2013 Elsevier Ltd. All rights reserved.

Inter-strand resistance measurements in the termination of the ITER SULTAN samples

International Nuclear Information System (INIS)

Cau, F; Bruzzone, P

2009-01-01

In cabled conductors a perfect uniformity of the current among the strands is hardly reached, due to the non-homogeneity of the contact resistance distribution between the strands and the copper of the electrical terminations. In the case of large current unbalance, the overloaded strands hit the critical surface at high field early, developing a current sharing voltage, which drives the redistribution of the current, mainly in the electrical terminations where the inter-strand resistance is lower than in the high field conductor. If the inter-strand resistance in the termination is low, the voltage levels are sufficiently low to allow an effective redistribution of the current to the less loaded strands. The inter-strand resistance of three different termination layouts of ITER short length samples is measured to make a database available which can be used to qualify the layout of the joints and their capability of redistributing the current among the strands.

Application of a multilayer perceptron neural network to phytoplankton concentration using marine reflectance measures

Science.gov (United States)

Su, Feng-Chun; Ho, Chung-Ru; Kuo, Nan-Jung

2005-01-01

The multilayer perceptron (MLP) neural network have been widely used to fit non-linear transfer function and performed well. In this study, we use MLP to estimate chlorophyll-a concentrations from marine reflectance measures. The optical data were assembled from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Bio-optical Algorithm Mini-workshop (SeaBAM). Most bio-optical algorithms use simple ratios of reflectance in blue and green bands or combinations of ratios as parameters for regression analysis. Regression analysis has limitations for nonlinear function. Neural network, however, have been shown better performance for nonlinear problems. The result showed that accuracy of chlorophyll-a concentration using MLP is much higher than that of regression method. Nevertheless, using all of the five bands as input can derive the best performance. The results showed that each band could carry some useful messages for ocean color remote sensing. Only using band ratio (OC2) or band switch (OC4) might lose some available information. By preprocessing reflectance data with the principle component analysis (PCA), MLP could derive much better accuracy than traditional methods. The result showed that the reflectance of all bands should not be ignored for deriving the chlorophyll-a concentration because each band carries different useful ocean color information.

Shortfalls in the global protected area network at representing marine biodiversity.

Science.gov (United States)

Klein, Carissa J; Brown, Christopher J; Halpern, Benjamin S; Segan, Daniel B; McGowan, Jennifer; Beger, Maria; Watson, James E M

2015-12-03

The first international goal for establishing marine protected areas (MPAs) to conserve the ocean's biodiversity was set in 2002. Since 2006, the Convention on Biological Diversity (CBD) has driven MPA establishment, with 193 parties committed to protecting >10% of marine environments globally by 2020, especially 'areas of particular importance for biodiversity' (Aichi target 11). This has resulted in nearly 10 million km(2) of new MPAs, a growth of ~360% in a decade. Unlike on land, it is not known how well protected areas capture marine biodiversity, leaving a significant gap in our understanding of existing MPAs and future protection requirements. We assess the overlap of global MPAs with the ranges of 17,348 marine species (fishes, mammals, invertebrates), and find that 97.4% of species have biodiversity. Our results offer strategic guidance on where MPAs should be placed to support the CBD's overall goal to avert biodiversity loss. Achieving this goal is imperative for nature and humanity, as people depend on biodiversity for important and valuable services.

RRP Nb3Sn strand studies for LARP

International Nuclear Information System (INIS)

Barzi, Emanuela; Bossert, Rodger; Caspi, Shlomo; Dietderich, Daniel R.; Ferracin, Paolo; Ghosh, Arup; Turrioni, Daniele

2006-01-01

The Nb 3 Sn strand chosen for the next step in the magnet R and D of the U.S. LHC Accelerator Research Program is the 54/61 sub-element Restacked Rod Process by Oxford Instruments, Superconducting Technology. To ensure that the 0.7 mm RRP strands to be used in the upcoming LARP magnets are suitable, extensive studies were performed. Measurements included the critical current, e , using the voltage-current (V-I) method, the stability current, I S , as the minimal quench current obtained with the voltage-field (V-H) method, and RRR. Magnetization was measured at low and high fields to determine the effective filament size and to detect flux jumps. Effects of heat treatment temperature and durations on I e and I S were also studied. Using strand billet qualification and tests of strands extracted from cables, the short sample limits of magnet performance were obtained. The details and the results of this investigation are herein described

RRP Nb3Sn Strand Studies for LARP

International Nuclear Information System (INIS)

Barzi, Emanuela; Bossert, Rodger; Caspi, Shlomo; Dietderich, Daniel R.; Ferracin, Paolo; Ghosh, Arup; Turrioni, Daniele

2007-01-01

The Nb 3 Sn strand chosen for the next step in the magnet R and D of the U.S. LHC Accelerator Research Program is the 54/61 sub-element Restacked Rod Process by Oxford Instruments, Superconducting Technology. To ensure that the 0.7 mm RRP strands to be used in the upcoming LARP magnets are suitable, extensive studies were performed. Measurements included the critical current, I c , using the voltage-current (V-I) method, the stability current, I S , as the minimal quench current obtained with the voltage-field (V-H) method, and RRR. Magnetization was measured at low and high fields to determine the effective filament size and to detect flux jumps. Effects of heat treatment temperature and durations on I c and I S were also studied. Using strand billet qualification and tests of strands extracted from cables, the short sample limits of magnet performance were obtained. The details and the results of this investigation are herein described

Flexural behavior of bonded post-tensioned concrete beams under strand corrosion

International Nuclear Information System (INIS)

Zhang, Xuhui; Wang, Lei; Zhang, Jianren; Ma, Yafei; Liu, Yongming

2017-01-01

Highlights: • Flexural behavior of bonded PT beams with strand corrosion is experimental tested. • Cracking, stiffness, ultimate strength, failure & ductility of beams are clarified. • A coefficient is proposed to measure incompatible strain between strand & concrete. - Abstract: An experimental test is performed to investigate the flexural behavior of bonded post-tensioned concrete beams under strand corrosion. Eight beams are designed and subjected to accelerated method to different corrosion levels. The initial stiffness of beams is observed by cyclic loading-unloading test during the corrosion procedure. Corrosion effects on concrete cracking, post-cracking stiffness, ultimate strength, failure mode and ductility are then clarified by the flexural test. And, a coefficient is introduced to quantify the incompatible strain between corroded strand and concrete. Results show that the prestress force loss of strand has almost the linear relation with corrosion loss. Strand corrosion affects slightly the initial stiffness of beam before flexural cracking, but degrades significantly the post-cracking stiffness of beam as the corrosion loss exceeds 27.0%. Slight corrosion of strand has little effects on beams flexural behavior. The severe corrosion, however, decreases the number of crack, changes the failure mode form the concrete crushing to strand rupture, degrades the ductility and the ultimate strength of beams, and leads to the incompatible strain between strand and concrete. In the present test, the incompatible strain decreases about 20% of the flexural strength as the corrosion loss exceeds 27.0%.

Flexural behavior of bonded post-tensioned concrete beams under strand corrosion

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xuhui [College of Civil Engineering and Mechanics, Xiangtan University, 411105 Xiangtan (China); School of Civil Engineering and Architecture, Changsha University of Science & Technology, 410114 Changsha (China); Industry Key Laboratory of Traffic Infrastructure Security Risk Management (CSUST), 410114 Changsha (China); Wang, Lei, E-mail: leiwlei@hotmail.com [School of Civil Engineering and Architecture, Changsha University of Science & Technology, 410114 Changsha (China); Industry Key Laboratory of Traffic Infrastructure Security Risk Management (CSUST), 410114 Changsha (China); Zhang, Jianren; Ma, Yafei [School of Civil Engineering and Architecture, Changsha University of Science & Technology, 410114 Changsha (China); Industry Key Laboratory of Traffic Infrastructure Security Risk Management (CSUST), 410114 Changsha (China); Liu, Yongming [School for Engineering of Matter, Transport and Energy, Arizona State University, 85281 Tempe, AZ (United States)

2017-03-15

Highlights: • Flexural behavior of bonded PT beams with strand corrosion is experimental tested. • Cracking, stiffness, ultimate strength, failure & ductility of beams are clarified. • A coefficient is proposed to measure incompatible strain between strand & concrete. - Abstract: An experimental test is performed to investigate the flexural behavior of bonded post-tensioned concrete beams under strand corrosion. Eight beams are designed and subjected to accelerated method to different corrosion levels. The initial stiffness of beams is observed by cyclic loading-unloading test during the corrosion procedure. Corrosion effects on concrete cracking, post-cracking stiffness, ultimate strength, failure mode and ductility are then clarified by the flexural test. And, a coefficient is introduced to quantify the incompatible strain between corroded strand and concrete. Results show that the prestress force loss of strand has almost the linear relation with corrosion loss. Strand corrosion affects slightly the initial stiffness of beam before flexural cracking, but degrades significantly the post-cracking stiffness of beam as the corrosion loss exceeds 27.0%. Slight corrosion of strand has little effects on beams flexural behavior. The severe corrosion, however, decreases the number of crack, changes the failure mode form the concrete crushing to strand rupture, degrades the ductility and the ultimate strength of beams, and leads to the incompatible strain between strand and concrete. In the present test, the incompatible strain decreases about 20% of the flexural strength as the corrosion loss exceeds 27.0%.

LHC superconducting strand

CERN Multimedia

Patrice Loiez

1999-01-01

This cross-section through a strand of superconducting matieral as used in the LHC shows the 8000 Niobium-Titanium filaments embedded like a honeycomb in copper. When cooled to 1.9 degrees above absolute zero in the LHC accelerator, these filaments will have zero resistance and so will carry a high electric current with no energy loss.

A Novel Computational Method to Reduce Leaky Reaction in DNA Strand Displacement

Directory of Open Access Journals (Sweden)

Xin Li

2015-01-01

Full Text Available DNA strand displacement technique is widely used in DNA programming, DNA biosensors, and gene analysis. In DNA strand displacement, leaky reactions can cause DNA signals decay and detecting DNA signals fails. The mostly used method to avoid leakage is cleaning up after upstream leaky reactions, and it remains a challenge to develop reliable DNA strand displacement technique with low leakage. In this work, we address the challenge by experimentally evaluating the basic factors, including reaction time, ratio of reactants, and ion concentration to the leakage in DNA strand displacement. Specifically, fluorescent probes and a hairpin structure reporting DNA strand are designed to detect the output of DNA strand displacement, and thus can evaluate the leakage of DNA strand displacement reactions with different reaction time, ratios of reactants, and ion concentrations. From the obtained data, mathematical models for evaluating leakage are achieved by curve derivation. As a result, it is obtained that long time incubation, high concentration of fuel strand, and inappropriate amount of ion concentration can weaken leaky reactions. This contributes to a method to set proper reaction conditions to reduce leakage in DNA strand displacement.

A Stress Measurement Method for Steel Strands Based on LC Oscillation

Directory of Open Access Journals (Sweden)

Dongjun Chen

2018-01-01

Full Text Available The prestress loss is one of the main factors affecting the safety of prestressed concrete structure. While the detecting signals like sound and light are difficult to spread in steel strands, there is no effective method for prestress detection of the bonded prestressed steel strands in existing structures yet. In this paper, taking into consideration that the electromagnetic oscillation characteristic can make the signal propagate effectively on the bonded prestressed steel strands, a nondestructive prestress detection method based on the electromagnetic effect to detect oscillation frequency is proposed. In a detection circuit, the steel strands are simulated as an inductance component, in which an induced electromagnetic signal passes through the steel strands to form resonance. And then, a frequency meter is used to detect the oscillation frequency of the resonant circuit. The oscillation frequency is supposed to have relationship with the prestress loading on the steel strands. A section of steel strands with a length of 1.2 m is adopted to test the correlation of stress and oscillation frequency. Both the theoretical and experimental results show that the resonant frequency of the circuit decreases with the increase of the stress of the strand and is linear in a certain range.

A model capturing novel strand symmetries in bacterial DNA

International Nuclear Information System (INIS)

Sobottka, Marcelo; Hart, Andrew G.

2011-01-01

Highlights: → We propose a simple stochastic model to construct primitive DNA sequences. → The model provide an explanation for Chargaff's second parity rule in primitive DNA sequences. → The model is also used to predict a novel type of strand symmetry in primitive DNA sequences. → We extend the results for bacterial DNA sequences and compare distributional properties intrinsic to the model to statistical estimates from 1049 bacterial genomes. → We find out statistical evidences that the novel type of strand symmetry holds for bacterial DNA sequences. -- Abstract: Chargaff's second parity rule for short oligonucleotides states that the frequency of any short nucleotide sequence on a strand is approximately equal to the frequency of its reverse complement on the same strand. Recent studies have shown that, with the exception of organellar DNA, this parity rule generally holds for double-stranded DNA genomes and fails to hold for single-stranded genomes. While Chargaff's first parity rule is fully explained by the Watson-Crick pairing in the DNA double helix, a definitive explanation for the second parity rule has not yet been determined. In this work, we propose a model based on a hidden Markov process for approximating the distributional structure of primitive DNA sequences. Then, we use the model to provide another possible theoretical explanation for Chargaff's second parity rule, and to predict novel distributional aspects of bacterial DNA sequences.

Sub-ensemble monitoring of DNA strand displacement using multiparameter single-molecule FRET

OpenAIRE

Baltierra Jasso, Laura; Morten, Michael; Magennis, Steven William

2018-01-01

Non-enzymatic DNA strand displacement is an important mechanism in dynamic DNA nanotechnology. Here we show that the large parameter space that is accessible by single-molecule FRET is ideal for the simultaneous monitoring of multiple reactants and products of DNA strand exchange reactions. We monitored the strand displacement from double-stranded DNA (dsDNA) by single-stranded DNA (ssDNA) at 37 °C; the data were modelled as a second-order reaction approaching equilibrium, with a rate constan...

Stranding Events of Kogia Whales along the Brazilian Coast.

Directory of Open Access Journals (Sweden)

Jailson F Moura

Full Text Available The genus Kogia, which comprises only two extant species, Kogia sima and Kogia breviceps, represents one of the least known groups of cetaceans in the global ocean. In some coastal regions, however, stranding events of these species have been relatively common over the last decades. Stranding provides the opportunity to investigate the biology of these cetaceans and to explore the epidemiological aspects associated with the mortality of the organisms found on the beach. A number of disturbances (including pelagic fisheries, chemical pollution, boat strikes, and noise pollution have been confirmed to pose a particular threat to the Kogia species. However, no study has yet investigated potential relationships between environmental conditions and stranding events. Here we analyse how a collection of environmental, physical, and biological variables, such as wind, sea surface temperature (SST, water depth, and chlorophyll-a, correlate to Kogia stranding events along the Brazilian coast. The results of our statistical analyses suggest that K. sima is more likely found in warm tropical waters, which provide an explanation for the high frequency of stranding in northeastern Brazilian coast. In contrast, K. breviceps appears to have a preference for temperate and productive waters. Wind speed results to be also an important factor for predicting Kogia strandings in Brazilian coast. Additionally, literature information in combination with our own data and analyses of stomach contents confirms that oceanic cephalopods constitute the primary nutritional source of both Kogia species. By using the available information as a qualitative proxy for habitat preference and feeding ecology, our study provides a novel and comprehensive assessment of Kogia stranding data in relation to environmental conditions along the Brazilian coast.

75 FR 36678 - Prestressed Concrete Steel Wire Strand From China; Determinations

Science.gov (United States)

2010-06-28

... prestressed concrete steel wire strand (PC strand), provided for in subheading 7312.10.30 of the Harmonized... Publication 4162 (June 2010), entitled Prestressed Concrete Steel Wire Strand from China: Investigation Nos... INTERNATIONAL TRADE COMMISSION [Investigation Nos. 701-TA-464 and 731-TA-1160 (Final)] Prestressed...

Flap Endonuclease 1 Limits Telomere Fragility on the Leading Strand*

Science.gov (United States)

Teasley, Daniel C.; Parajuli, Shankar; Nguyen, Mai; Moore, Hayley R.; Alspach, Elise; Lock, Ying Jie; Honaker, Yuchi; Saharia, Abhishek; Piwnica-Worms, Helen; Stewart, Sheila A.

2015-01-01

The existence of redundant replication and repair systems that ensure genome stability underscores the importance of faithful DNA replication. Nowhere is this complexity more evident than in challenging DNA templates, including highly repetitive or transcribed sequences. Here, we demonstrate that flap endonuclease 1 (FEN1), a canonical lagging strand DNA replication protein, is required for normal, complete leading strand replication at telomeres. We find that the loss of FEN1 nuclease activity, but not DNA repair activities, results in leading strand-specific telomere fragility. Furthermore, we show that FEN1 depletion-induced telomere fragility is increased by RNA polymerase II inhibition and is rescued by ectopic RNase H1 expression. These data suggest that FEN1 limits leading strand-specific telomere fragility by processing RNA:DNA hybrid/flap intermediates that arise from co-directional collisions occurring between the replisome and RNA polymerase. Our data reveal the first molecular mechanism for leading strand-specific telomere fragility and the first known role for FEN1 in leading strand DNA replication. Because FEN1 mutations have been identified in human cancers, our findings raise the possibility that unresolved RNA:DNA hybrid structures contribute to the genomic instability associated with cancer. PMID:25922071

Characteristics of Cu stabilized Nb3Al strands with low Cu ratio

Energy Technology Data Exchange (ETDEWEB)

Kikuchi, A.; Yamada, R.; Barzi, E.; Kobayashi, M.; Lamm, M.; Nakagawa, K.; Sasaki, K.; Takeuchi, T.; Turrioni, D.; Zlobin, A.V.; /NIMC, Tsukuba /Fermilab /Hitachi, Tsuchiura Works /KEK, Tsukuba

2008-12-01

Characteristics of recently developed F4-Nb{sub 3}Al strand with low Cu ratio are described. The overall J{sub c} of the Nb{sub 3}Al strand could be easily increased by decreasing of the Cu ratio. Although the quench of a pulse-like voltage generation is usually observed in superconducting unstable conductor, the F4 strand with a low Cu ratio of 0.61 exhibited an ordinary critical transition of gradual voltage generation. The F4 strand does not have magnetic instabilities at 4.2 K because of the tantalum interfilament matrix. The overall J{sub c} of the F4 strand achieved was 80-85% of the RRP strand. In the large mechanical stress above 100 MPa, the overall J{sub c} of the F4 strand might be comparable to that of high J{sub c} RRP-Nb{sub 3}Sn strands. The Rutherford cable with a high packing factor of 86.5% has been fabricated using F4 strands. The small racetrack magnet, SR07, was also fabricated by a 14 m F4 cable. The quench current, I{sub q}, of SR07 were obtained 22.4 kA at 4.5 K and 25.2 kA at 2.2 K. The tantalum matrix Nb{sub 3}Al strands are promising for the application of super-cooled high-field magnets as well as 4.2 K operation magnets.

Characterization of a parallel-stranded DNA hairpin

International Nuclear Information System (INIS)

Germann, M.W.; Vogel, H.J.; Pon, R.T.; van de Sande, J.H.

1989-01-01

Recently, the authors have shown that synthetic DNA containing homooligomeric A-T base pairs can form a parallel-stranded intramolecular hairpin structure. In the present study, they have employed NMR and optical spectroscopy to investigate the structure of the parallel-stranded (PS) DNA hairpin 3'-d(T) 8 C 4 (A) 8 -3' and the related antiparallel (APS) hair 5'-d(T) 8 C 4 (A) 8 -3'. The parallel orientation of the strands in the PS oligonucleotide is achieved by introducing a 5'-5' phosphodiester linkage in the hairpin loop. Ultraviolet spectroscopic and fluorescence data of drug binding are consistent with the formation of PS and APS structures, respectively, in these two hairpins. Vacuum circular dichroism measurements in combination with theoretical CD calculations indicate that the PS structure forms a right-handed helix. 31 P NMR measurements indicate that the conformation of the phosphodiester backbone of the PS structure is not drastically different from that of the APS control. The presence of slowly exchanging imino protons at 14 ppm and the observation of nuclear Overhauser enhancement between imino protons and the AH-2 protons demonstrate that similar base pairing and base stacking between T and A residues occur in both hairpins. On the basis of NOESY measurements, they find that the orientation of the bases is in the anti region and that the sugar puckering is in the 2'-endo range. The results indicate a B-like conformation for each of the strands in the stem part of the PS hairpin and reverse Watson-Crick base pairing between the T and A residues. These data are consistent with a previously calculated structure for parallel-stranded DNA

Strand displacement activated peroxidase activity of hemin for fluorescent DNA sensing.

Science.gov (United States)

Wang, Quanbo; Xu, Nan; Gui, Zhen; Lei, Jianping; Ju, Huangxian; Yan, Feng

2015-10-07

To efficiently regulate the catalytic activity of the peroxidase mimic hemin, this work designs a double-stranded DNA probe containing an intermolecular dimer of hemin, whose peroxidase activity can be activated by a DNA strand displacement reaction. The double-stranded probe is prepared by annealing two strands of hemin labelled DNA oligonucleotides. Using the fluorescent oxidation product of tyramine by H2O2 as a tracing molecule, the low peroxidase activity of the hemin dimer ensures a low fluorescence background. The strand displacement reaction of the target DNA dissociates the hemin dimer and thus significantly increases the catalytic activity of hemin to produce a large amount of dityramine for fluorescence signal readout. Based on the strand displacement regulated peroxidase activity, a simple and sensitive homogeneous fluorescent DNA sensing method is proposed. The detection can conveniently be carried out in a 96-well plate within 20 min with a detection limit of 0.18 nM. This method shows high specificity, which can effectively distinguish single-base mismatched DNA from perfectly matched target DNA. The DNA strand displacement regulated catalytic activity of hemin has promising application in the determination of various DNA analytes.

210Polonium and 210lead content of marine birds from Southeastern Brazil

International Nuclear Information System (INIS)

Godoy, José Marcus; Siciliano, Salvatore; Carvalho, Zenildo Lara de; Tavares, Davi C.; Fulgencio de Moura, Jaílson

2014-01-01

In this study, we report the 210 Po and 210 Pb concentrations of bone, muscle and liver samples that were obtained from twelve different marine bird species stranded on beaches in the central–north region of Rio de Janeiro State. Both radionuclides were highly concentrated in the liver samples; however, the lowest mean 210 Po/ 210 Pb activity ratio (1.3) was observed in bones compared with liver and muscle (16.8 and 13.8, respectively). Among the species that were studied, Fregata magnificens, with a diet based exclusively on fish, had the lowest 210 Pb and 210 Po concentrations and the lowest 210 Po/ 210 Pb activity ratio. The 210 Po concentrations in Puffinus spp. liver samples followed a log-normal distribution, with a geometric mean of 300 Bq kg -1 wet weight . Only two references pertaining to 210 Po in marine birds were found in a Web of Science search of the literature, and each study reported a different concentration value. The values determined in this experiment are consistent with those in one of the previous studies, which also included one of the species studied in this work. No values for 210 Pb in marine birds have been published previously. - Highlights: • 210 Po and 210 Pb were determined in muscle, liver and bone samples of marine birds. • For both radionuclides, the highest concentrations were observed on liver samples. • Only three previous publications on 210 Po in marine birds were found in the literature. • The obtained results represent the first one related to 210 Pb in marine birds

Torsional regulation of hRPA-induced unwinding of double-stranded DNA

NARCIS (Netherlands)

De Vlaminck, I.; Vidic, I.; Van Loenhout, M.T.J.; Kanaar, R.; Lebbink, J.H.G.; Dekker, C.

2010-01-01

All cellular single-stranded (ss) DNA is rapidly bound and stabilized by single stranded DNA-binding proteins (SSBs). Replication protein A, the main eukaryotic SSB, is able to unwind double-stranded (ds) DNA by binding and stabilizing transiently forming bubbles of ssDNA. Here, we study the

Role of stranded gas in increasing global gas supplies

Science.gov (United States)

Attanasi, E.D.; Freeman, P.A.

2013-01-01

This report synthesizes the findings of three regional studies in order to evaluate, at the global scale, the contribution that stranded gas resources can make to global natural gas supplies. Stranded gas, as defined for this study, is natural gas in discovered conventional gas and oil fields that is currently not commercially producible for either physical or economic reasons. The regional studies evaluated the cost of bringing the large volumes of undeveloped gas in stranded gas fields to selected markets. In particular, stranded gas fields of selected Atlantic Basin countries, north Africa, Russia, and central Asia are screened to determine whether the volumes are sufficient to meet Europe’s increasing demand for gas imports. Stranded gas fields in Russia, central Asia, Southeast Asia, and Australia are also screened to estimate development, production, and transport costs and corresponding gas volumes that could be supplied to Asian markets in China, India, Japan, and South Korea. The data and cost analysis presented here suggest that for the European market and the markets examined in Asia, the development of stranded gas provides a way to meet projected gas import demands for the 2020-to-2040 period. Although this is a reconnaissance-type appraisal, it is based on volumes of gas that are associated with individual identified fields. Individual field data were carefully examined. Some fields were not evaluated because current technology was insufficient or it appeared the gas was likely to be held off the export market. Most of the evaluated stranded gas can be produced and delivered to markets at costs comparable to historical prices. Moreover, the associated volumes of gas are sufficient to provide an interim supply while additional technologies are developed to unlock gas diffused in shale and hydrates or while countries transition to making a greater use of renewable energy sources.

Photochemical Acceleration of DNA Strand Displacement by Using Ultrafast DNA Photo-crosslinking.

Science.gov (United States)

Nakamura, Shigetaka; Hashimoto, Hirokazu; Kobayashi, Satoshi; Fujimoto, Kenzo

2017-10-18

DNA strand displacement is an essential reaction in genetic recombination, biological processes, and DNA nanotechnology. In particular, various DNA nanodevices enable complicated calculations. However, it takes time before the output is obtained, so acceleration of DNA strand displacement is required for a rapid-response DNA nanodevice. Herein, DNA strand displacement by using DNA photo-crosslinking to accelerate this displacement is evaluated. The DNA photo-crosslinking of 3-cyanovinylcarbazole ( CNV K) was accelerated at least 20 times, showing a faster DNA strand displacement. The rate of photo-crosslinking is a key factor and the rate of DNA strand displacement is accelerated through ultrafast photo-crosslinking. The rate of DNA strand displacement was regulated by photoirradiation energy. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Corrosion characteristics of unprotected post-tensioning strands under stress.

Science.gov (United States)

2014-05-01

An investigation was conducted to determine the effect of stress condition : and environmental exposure on corrosion of post-tensioned strands during ungrouted periods. : Exposures for periods of up to 4 weeks of stressed, as-received strand placed i...

Stranded cost recovery in electricity market reforms in the US

International Nuclear Information System (INIS)

Woo, C.K.; Lloyd, D.; Karimov, R.; Tishler, A.

2003-01-01

An important element of an electricity market reform is stranded cost recovery. This paper explains the cause of stranded costs, describes four recovery mechanisms, evaluates these mechanisms using the criteria of recovery certainty, economic efficiency and equity, reviews the financial performance of 12 utilities in the US in connection to stranded cost recovery, and shows why the mechanism used in California has contributed to the reform failure in that state. (Author)

A novel single fluorophore-labeled double-stranded oligonucleotide probe for fluorescence-enhanced nucleic acid detection based on the inherent quenching ability of deoxyguanosine bases and competitive strand-displacement reaction.

Science.gov (United States)

Zhang, Yingwei; Tian, Jingqi; Li, Hailong; Wang, Lei; Sun, Xuping

2012-01-01

We develop a novel single fluorophore-labeled double-stranded oligonucleotide (OND) probe for rapid, nanostructure-free, fluorescence-enhanced nucleic acid detection for the first time. We further demonstrate such probe is able to well discriminate single-base mutation in nucleic acid. The design takes advantage of an inherent quenching ability of guanine bases. The short strand of the probe is designed with an end-labeled fluorophore that is placed adjacent to two guanines as the quencher located on the long opposite strand, resulting in great quenching of dye fluorescence. In the presence of a target complementary to the long strand of the probe, a competitive strand-displacement reaction occurs and the long strand forms a more stable duplex with the target, resulting in the two strands of the probe being separated from each other. As a consequence of this displacement, the fluorophore and the quencher are no longer in close proximity and dye fluorescence increases, signaling the presence of target.

Bioprinting Using Mechanically Robust Core-Shell Cell-Laden Hydrogel Strands.

Science.gov (United States)

Mistry, Pritesh; Aied, Ahmed; Alexander, Morgan; Shakesheff, Kevin; Bennett, Andrew; Yang, Jing

2017-06-01

The strand material in extrusion-based bioprinting determines the microenvironments of the embedded cells and the initial mechanical properties of the constructs. One unmet challenge is the combination of optimal biological and mechanical properties in bioprinted constructs. Here, a novel bioprinting method that utilizes core-shell cell-laden strands with a mechanically robust shell and an extracellular matrix-like core has been developed. Cells encapsulated in the strands demonstrate high cell viability and tissue-like functions during cultivation. This process of bioprinting using core-shell strands with optimal biochemical and biomechanical properties represents a new strategy for fabricating functional human tissues and organs. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mechanical behaviors of multi-filament twist superconducting strand under tensile and cyclic loading

Science.gov (United States)

Wang, Xu; Li, Yingxu; Gao, Yuanwen

2016-01-01

The superconducting strand, serving as the basic unit cell of the cable-in-conduit-conductors (CICCs), is a typical multi-filament twist composite which is always subjected to a cyclic loading under the operating condition. Meanwhile, the superconducting material Nb3Sn in the strand is sensitive to strain frequently relating to the performance degradation of the superconductivity. Therefore, a comprehensive study on the mechanical behavior of the strand helps understanding the superconducting performance of the strained Nb3Sn strands. To address this issue, taking the LMI (internal tin) strand as an example, a three-dimensional structural finite element model, named as the Multi-filament twist model, of the strand with the real configuration of the LMI strand is built to study the influences of the plasticity of the component materials, the twist of the filament bundle, the initial thermal residual stress and the breakage and its evolution of the filaments on the mechanical behaviors of the strand. The effective properties of superconducting filament bundle with random filament breakage and its evolution versus strain are obtained based on the damage theory of fiber-reinforced composite materials proposed by Curtin and Zhou. From the calculation results of this model, we find that the occurrence of the hysteresis loop in the cyclic loading curve is determined by the reverse yielding of the elastic-plastic materials in the strand. Both the initial thermal residual stress in the strand and the pitch length of the filaments have significant impacts on the axial and hysteretic behaviors of the strand. The damage of the filaments also affects the axial mechanical behavior of the strand remarkably at large axial strain. The critical current of the strand is calculated by the scaling law with the results of the Multi-filament twist model. The predicted results of the Multi-filament twist model show an acceptable agreement with the experiment.

Molecular investigation of evaporation of biodroplets containing single-strand DNA on graphene surface.

Science.gov (United States)

Akbari, Fahimeh; Foroutan, Masumeh

2018-02-14

In this study, the water droplet behaviour of four different types of single-strand DNA with homogeneous base sequence on a graphene substrate during evaporation of the droplet was investigated using molecular dynamics (MD) simulation. The simulation results indicated that the evaporation depended on the DNA sequence. The observed changes can be divided into four parts: (i) vaporization mode, (ii) evaporation flux, (iii) mechanism of single-strand placement on the surface, and (iv) consideration of remaining single strands after evaporation. Our simulation observations indicated different evaporation modes for thymine biodroplets as compared to those for other biodroplets. The evaporation of the thymine biodroplets occurred with an increase in the contact angle, while that of the other biodroplets occur in a constant contact angle mode. Moreover, thymine biodroplets generate the lowest contact line compared to other single strands, and it is always placed far away from the centre of the droplets during evaporation. Investigating variations in the evaporation flux shows that thymine has the highest evaporation flux and guanine has the lowest. Moreover, during initial evaporation, the flux of evaporation increases at the triple point of the biodroplets containing thymine single strands, while it decreases in the other biodroplets. The following observation was obtained from the study of the placement of single strands on the substrate: guanine and thymine interacted slower than other single strands during evaporation with graphene, adenine single strand had a higher folding during evaporation, and guanine single strand showed the lowest end-to-end distance. The investigation of single-strand DNA after evaporation shows that adenine produces the most stable structure at the end of evaporation. In addition, cytosine is the most stretched single-strand DNA due to its lack of internal π-π stacking and hydrogen bonding. Therefore, cytosine single strand is more

Flap Endonuclease 1 Limits Telomere Fragility on the Leading Strand.

Science.gov (United States)

Teasley, Daniel C; Parajuli, Shankar; Nguyen, Mai; Moore, Hayley R; Alspach, Elise; Lock, Ying Jie; Honaker, Yuchi; Saharia, Abhishek; Piwnica-Worms, Helen; Stewart, Sheila A

2015-06-12

The existence of redundant replication and repair systems that ensure genome stability underscores the importance of faithful DNA replication. Nowhere is this complexity more evident than in challenging DNA templates, including highly repetitive or transcribed sequences. Here, we demonstrate that flap endonuclease 1 (FEN1), a canonical lagging strand DNA replication protein, is required for normal, complete leading strand replication at telomeres. We find that the loss of FEN1 nuclease activity, but not DNA repair activities, results in leading strand-specific telomere fragility. Furthermore, we show that FEN1 depletion-induced telomere fragility is increased by RNA polymerase II inhibition and is rescued by ectopic RNase H1 expression. These data suggest that FEN1 limits leading strand-specific telomere fragility by processing RNA:DNA hybrid/flap intermediates that arise from co-directional collisions occurring between the replisome and RNA polymerase. Our data reveal the first molecular mechanism for leading strand-specific telomere fragility and the first known role for FEN1 in leading strand DNA replication. Because FEN1 mutations have been identified in human cancers, our findings raise the possibility that unresolved RNA:DNA hybrid structures contribute to the genomic instability associated with cancer. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Conservation, spillover and gene flow within a network of Northern European marine protected areas.

Directory of Open Access Journals (Sweden)

Mats Brockstedt Olsen Huserbråten

Full Text Available To ensure that marine protected areas (MPAs benefit conservation and fisheries, the effectiveness of MPA designs has to be evaluated in field studies. Using an interdisciplinary approach, we empirically assessed the design of a network of northern MPAs where fishing for European lobster (Homarusgammarus is prohibited. First, we demonstrate a high level of residency and survival (50% for almost a year (363 days within MPAs, despite small MPA sizes (0.5-1 km(2. Second, we demonstrate limited export (4.7% of lobsters tagged within MPAs (N = 1810 to neighbouring fished areas, over a median distance of 1.6 km out to maximum 21 km away from MPA centres. In comparison, median movement distance of lobsters recaptured within MPAs was 164 m, and recapture rate was high (40%. Third, we demonstrate a high level of gene flow within the study region, with an estimated F ST of less than 0.0001 over a ≈ 400 km coastline. Thus, the restricted movement of older life stages, combined with a high level of gene flow suggests that connectivity is primarily driven by larval drift. Larval export from the MPAs can most likely affect areas far beyond their borders. Our findings are of high importance for the design of MPA networks for sedentary species with pelagic early life stages.

Cetacean strandings along the coast of Izmir Bay, Turkey

NARCIS (Netherlands)

Guclusoy, H.; Veryeri, N.; Cirik, S.

2004-01-01

The present paper provides information on the stranding of cetaceans in Izmir Bay, Aegean Sea, between 1992 and 2004. The data were collected opportunistically during sightings and stranding data collection for Monk Seals. A total of 12 cetaceans, namely Bottle-nosed Dolphin, Tursiops truncatus

DNA turnover and strand breaks in Escherichia coli

International Nuclear Information System (INIS)

Hanawalt, P.; Grivell, A.; Nakayama, H.

1975-01-01

The extent of DNA turnover has been measured in a dnaB mutant of Escherichia coli, temperature sensitive for semiconservative DNA replication. At the nonpermissive temperature about 0.02 percent of the deoxynucleotides in DNA are exchanged per generation period. This turnover rate is markedly depressed in the presence of rifampicin. During thymine starvation strand breaks accumulate in the DNA of E. coli strains that are susceptible to thymineless death. Rifampicin suppresses the appearance of these breaks, consistent with our hypothesis that transcription may be accompanied by repairable single-strand breaks in DNA. DNA turnover is enhanced severalfold in strands containing 5-bromodeoxyuridine in place of thymidine, possibly because the analog (or the deoxyuridine, following debromination) is sometimes recognized and excised

Residual Resistivity Ratio (RRR) Measurements of LHC Superconducting NbTi Cable Strands

CERN Document Server

Charifoulline, Z

2006-01-01

The Rutherford-type superconducting NbTi cables of the LHC accelerator are currently manufactured by six industrial companies. As a part of the acceptance tests, the Residual Resistivity Ratio (RRR) of superconducting strands is systematically measured on virgin strands to qualify the strands before cabling and on extracted strands to qualify the cables and to check the final heat treatment (controlled oxidation to control interstrand resistance). More than 12000 samples of virgin and extracted strands have been measured during last five years. Results show good correlation with the measurements done by the companies and reflect well the technological process of cable production (strand annealing, cabling, cable heat treatment). This paper presents a description of the RRR-test station and the measurement procedure, the summary of the results over all suppliers and finally the correlation between RRR-values of the cables and the magnets.

Lungworm seroprevalence in free-ranging harbour seals and molecular characterisation of marine mammal MSP

Directory of Open Access Journals (Sweden)

Sophia Arlena Ulrich

2016-04-01

Full Text Available Harbour seals (Phoca vitulina are frequently infected with the lungworms Otostrongylus circumlitus and Parafilaroides gymnurus. The infection is often accompanied by secondary bacterial infections and can cause severe bronchopneumonia and even death in affected animals. Hitherto, the detection of lungworm infections was based on post mortem investigations from animals collected within stranding networks and a valid detection method for live free-ranging harbour seals was not available. Recently, an ELISA was developed for detecting lungworm antibodies in harbour seal serum, using major sperm protein (MSP of the bovine lungworm, Dictyocaulus viviparus as recombinant diagnostic antigen. To determine lungworm seroprevalence in free-ranging harbour seals, serum was taken from four different seal age groups (n = 313 resulting in an overall prevalence of 17.9% (18.9% of males, 16.7% of females. 0.7% of harbour seals up to six weeks of age were seropositive, as were 89% of seals between six weeks and six months, 53.6% between six and 18 months and 24.2% of seals over 18 months of age. In the 18 months and over age group, seropositive animals showed statistically significant reductions in body weight (P = 0.003 and length (P < 0.001. Sera from lungworm infected harbour seals in rehabilitation (n = 6 revealed that duration of antibody persistence may be similar to that of lungworm infected cattle, but further studies are needed to confirm this. Phylogenetic analyses of MSP sequences of different marine and terrestrial mammal parasitic nematodes revealed that lungworm MSP of the genus Dictyocaulus (superfamily Trichostrongyloidea is more closely related to metastrongylid marine mammal lungworms than to trichostrongylid nematodes of terrestrial hosts.

Tensile and dimensional properties of wood strands made from plantation southern pine lumber

Science.gov (United States)

Qinglin Wu; Zhiyong Cai; Jong N. Lee

2005-01-01

Working stresses and performance of strand composite lumber largely depend upon the properties of each individual strand. Southern pine strands from plantation lumber grown in southern Louisiana were investigated in this study in order to understand strand behaviors. The effects of hot-pressing and resin application on tensile modulus, strength, and dimensional...

Improving strand quality of upland oaks for use in oriented strand board

Science.gov (United States)

David B. DeValliance; Jody D. Gray; Shawn T. Grushecky

2013-01-01

Past research estimates that more than 1 million tons of oak logging residues go unused in West Virginia each year. Much research has been done investigating potential products and markets for this underutilized resource. West Virginia is home to an oriented strand board (OSB) producer that consumes large volumes of small diameter, low quality round wood. However, the...

TALEN-Induced Double-Strand Break Repair of CTG Trinucleotide Repeats

Directory of Open Access Journals (Sweden)

Valentine Mosbach

2018-02-01

Full Text Available Trinucleotide repeat expansions involving CTG/CAG triplets are responsible for several neurodegenerative disorders, including myotonic dystrophy and Huntington’s disease. Because expansions trigger the disease, contracting repeat length could be a possible approach to gene therapy for these disorders. Here, we show that a TALEN-induced double-strand break was very efficient at contracting expanded CTG repeats in yeast. We show that RAD51, POL32, and DNL4 are dispensable for double-strand break repair within CTG repeats, the only required genes being RAD50, SAE2, and RAD52. Resection was totally abolished in the absence of RAD50 on both sides of the break, whereas it was reduced in a sae2Δ mutant on the side of the break containing the longest repeat tract, suggesting that secondary structures at double-strand break ends must be removed by the Mre11-Rad50 complex and Sae2. Following the TALEN double-strand break, single-strand annealing occurred between both sides of the repeat tract, leading to repeat contraction.

Programmable autonomous synthesis of single-stranded DNA

Science.gov (United States)

Kishi, Jocelyn Y.; Schaus, Thomas E.; Gopalkrishnan, Nikhil; Xuan, Feng; Yin, Peng

2018-02-01

DNA performs diverse functional roles in biology, nanotechnology and biotechnology, but current methods for autonomously synthesizing arbitrary single-stranded DNA are limited. Here, we introduce the concept of primer exchange reaction (PER) cascades, which grow nascent single-stranded DNA with user-specified sequences following prescribed reaction pathways. PER synthesis happens in a programmable, autonomous, in situ and environmentally responsive fashion, providing a platform for engineering molecular circuits and devices with a wide range of sensing, monitoring, recording, signal-processing and actuation capabilities. We experimentally demonstrate a nanodevice that transduces the detection of a trigger RNA into the production of a DNAzyme that degrades an independent RNA substrate, a signal amplifier that conditionally synthesizes long fluorescent strands only in the presence of a particular RNA signal, molecular computing circuits that evaluate logic (AND, OR, NOT) combinations of RNA inputs, and a temporal molecular event recorder that records in the PER transcript the order in which distinct RNA inputs are sequentially detected.

Development of a 10 m quasi-isotropic strand assembled from 2G wires

Science.gov (United States)

Kan, Changtao; Wang, Yinshun; Hou, Yanbing; Li, Yan; Zhang, Han; Fu, Yu; Jiang, Zhe

2018-03-01

Quasi-isotropic strands made of second generation (2G) high temperature superconducting (HTS) wires are attractive to applications of high-field magnets at low temperatures and power transmission cables at liquid nitrogen temperature in virtue of their high current carrying capability and well mechanical property. In this contribution, a 10 m length quasi-isotropic strand is manufactured and successfully tested in liquid nitrogen to verify the feasibility of an industrial scale production of the strand by the existing cabling technologies. The strand with copper sheath consists of 72 symmetrically assembled 2G wires. The uniformity of critical properties of long quasi-isotropic strands, including critical current and n-value, is very important for their using. Critical currents as well as n-values of the strand are measured every 1 m respectively and compared with the simulation results. Critical current and n-value of the strand are calculated basing on the self-consistent model solved by the finite element method (FEM). Effects of self-field on the critical current and n-value distributions in wires of the strand are analyzed in detail. The simulation results show good agreement with the experimental data and the 10 m quasi-isotropic strand has good critical properties uniformity.

Corrosion characteristics of post-tensioning strands in ungrouted ducts : summary.

Science.gov (United States)

2011-01-01

To prevent corrosion of post-tensioning strands, FDOT construction specifications currently require post-tensioning ducts to be grouted within seven calendar days of strand installation. This period challenges construction schedules on large projects...

Compliant lightweight non-invasive standalone “Marine Skin” tagging system

KAUST Repository

Nassar, Joanna M.

2018-04-16

Current marine research primarily depends on weighty and invasive sensory equipment and telemetric network to understand the marine environment, including the diverse fauna it contains, as a function of animal behavior and size, as well as equipment longevity. To match animal morphology and activity within the surrounding marine environment, here we show a physically flexible and stretchable skin-like and waterproof autonomous multifunctional system, integrating Bluetooth, memory chip, and high performance physical sensors. The sensory tag is mounted on a swimming crab (Portunus pelagicus) and is capable of continuous logging of depth, temperature, and salinity within the harsh ocean environment. The fully packaged, ultra-lightweight (<2.4 g in water), and compliant “Marine Skin” system does not have any wired connection enabling safe and weightless cutting-edge approach to monitor and assess marine life and the ecosystem’s health to support conservation and management of marine ecosystems.

A single-strand specific lesion drives MMS-induced hyper-mutability at a double-strand break in yeast.

Science.gov (United States)

Yang, Yong; Gordenin, Dmitry A; Resnick, Michael A

2010-08-05

Localized hyper-mutability (LHM) can be important in evolution, immunity, and genetic diseases. We previously reported that single-strand DNA (ssDNA) can be an important source of damage-induced LHM in yeast. Here, we establish that the generation of LHM by methyl methanesulfonate (MMS) during repair of a chromosomal double-strand break (DSB) can result in over 0.2 mutations/kb, which is approximately 20,000-fold higher than the MMS-induced mutation density without a DSB. The MMS-induced mutations associated with DSB repair were primarily due to substitutions via translesion DNA synthesis at damaged cytosines, even though there are nearly 10 times more MMS-induced lesions at other bases. Based on this mutation bias, the promutagenic lesion dominating LHM is likely 3-methylcytosine, which is single-strand specific. Thus, the dramatic increase in mutagenesis at a DSB is concluded to result primarily from the generation of non-repairable lesions in ssDNA associated with DSB repair along with efficient induction of highly mutagenic ssDNA-specific lesions. These findings with MMS-induced LHM have broad biological implications for unrepaired damage generated in ssDNA and possibly ssRNA. Published by Elsevier B.V.

Italy. Report 1 [Marine Radioecology. Current Research and Future Scope

International Nuclear Information System (INIS)

Argiero, L.

1967-01-01

Present research programme: Studies on radioactive, biological and hydrographic characteristics of Tyrrhenian Sea; Organization of suitable control network of marine water and fauna: systematic measurement of present components of natural and artificial radioactivity of water, sediments and of the marine food chain techniques of sampling; analysis and measurement of particular radioisotopes in marine water. α, β, γ analysis of samples; γ spectrometry, research on 90 Sr and 137 Cs. Determination of concentration factors of radioisotopes which are responsible for contamination of principal components of the flora and fauna in the Tyrrhenian Sea; research of hydrographie factors influencing the distribution of marine radioactivity. Nuclide content of other organisms of the Tyrrhenian flora and fauna

Stem cell identity and template DNA strand segregation.

Science.gov (United States)

Tajbakhsh, Shahragim

2008-12-01

The quest for stem cell properties to distinguish their identity from that of committed daughters has led to a re-investigation of the notion that DNA strands are not equivalent, and 'immortal' DNA strands are retained in stem cells whereas newly replicated DNA strands segregate to the differentiating daughter cell during mitosis. Whether this process occurs only in stem cells, and also in all tissues, remains unclear. That individual chromosomes can be also partitioned non-randomly raises the question if this phenomenon is related to the immortal DNA hypothesis, and it underscores the need for high-resolution techniques to observe these events empirically. Although initially postulated as a mechanism to avoid DNA replication errors, alternative views including epigenetic regulation and sister chromatid silencing may provide insights into this process.

Knowledge base for growth and innovation in ocean economy: assembly and dissemination of marine data for seabed mapping - European Marine Observation Data Network - EMODnet Physics

Science.gov (United States)

Novellino, Antonio; Gorringe, Patrick; Schaap, Dick; Pouliquen, Sylvie; Rickards, Lesley; Manzella, Giuseppe

2014-05-01

The Physics preparatory action (MARE/2010/02 - Lot [SI2.579120]) had the overall objectives to provide access to archived and near real-time data on physical conditions as monitored by fixed stations and Ferrybox lines in all the European sea basins and oceans and to determine how well the data meet the needs of users. The existing EMODnet-Physics portal, www.emodnet-physics.eu, includes systems for physical data from the whole Europe (wave height and period, temperature of the water column, wind speed and direction, salinity of the water column, horizontal velocity of the water column, light attenuation, and sea level) provided mainly by fixed stations and ferry-box platforms, discovering related data sets (both near real time and historical data sets), viewing and downloading of the data from about 470 platforms across the European Sea basins. It makes layers of physical data and their metadata available for use and contributes towards the definition of an operational European Marine Observation and Data Network (EMODnet). It is based on a strong collaboration between EuroGOOS member institutes and its regional operational oceanographic systems (ROOSs), and it brings together two marine, but different, communities : the "real time" ocean observing institutes and centers and the National Oceanographic Data Centres (NODCs) that are in charge for archived ocean data validation, quality check and continuous update of data archives for marine environmental monitoring. EMODnet Physics is a Marine Observation and Data Information System that provides a single point of access to near real time and historical achieved data, it is built on existing infrastructure by adding value and avoiding any unnecessary complexity, it provides data access to any relevant user, and is aimed at attracting new data holders and providing better and more data. With a long term-vision for a sustained pan European Ocean Observation System EMODnet Physics is supporting the coordination of the

Mechanical behavior of Nb{sub 3}Sn strands under transverse electromagnetic loads

Energy Technology Data Exchange (ETDEWEB)

Ru, Yanyun; Yong, Huadong, E-mail: yonghd@lzu.edu.cn; Zhou, Youhe

2016-11-15

Highlights: • The contact forces between the strands under transverse electromagnetic load are considered. • The indentation depth for two-dimensional contact problem is calculated. • The strand damage for different layers is presented. • We discuss the effect of bending wavelength on the Nb{sub 3}Sn strand. - Abstract: The performance of Nb{sub 3}Sn cable-in-conduit-conductor (CICC) shows a significant degradation with increasing electromagnetic load in the International Thermonuclear Experimental Reactor (ITER). As the strand is under the compression caused by adjacent strands, the strand damage may occur for high contact force. In this paper, we present a 3D helix model based on the TEMLOP and FEMCAM to simulate the contact force among the strands under transverse load. The maximum linear strain and indentation depth induced by contact stress are calculated with two-dimensional contact model of cylinder. The numerical results are compared with the experimental values. Finally, the indentation depth is discussed for different layers and cross angles based on two models. With the increasing of layer number, the degradation of performance will occur. The short bending wavelength leads to small indentation depth.

Performance optimization of internal tin process multifilamentary Nb{sub 3}Sn strands

Energy Technology Data Exchange (ETDEWEB)

Zhang, Ke, E-mail: zhangke@c-wst.com [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China); Western Superconducting Technologies Co. Ltd, Xi’an, Shaanxi 710018 (China); State Engineering Lab. of Superconducting Material Preparation, Xi’an, Shaanxi 710018 (China); Zhang, Pingxiang [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China); Western Superconducting Technologies Co. Ltd, Xi’an, Shaanxi 710018 (China); State Engineering Lab. of Superconducting Material Preparation, Xi’an, Shaanxi 710018 (China); Northwest Institute for Non-ferrous Metal Research, Xi’an, Shaanxi 710016 (China); Shi, Yigong; Liu, Jianwei; Gao, Huixian; Li, Jianfeng; Liu, Xianghong; Feng, Yong [Western Superconducting Technologies Co. Ltd, Xi’an, Shaanxi 710018 (China); State Engineering Lab. of Superconducting Material Preparation, Xi’an, Shaanxi 710018 (China)

2016-11-01

Highlights: • J{sub c} increases by adding Sn cores in the interspaces, hysteresis loss increases at the same time. • Enlarger the number of filaments with the same Sn proportion will increase J{sub c} and hysteresis loss. • Cu split adopted in each sub-element leads to a low hysteresis loss. - Abstract: In this study, internal tin process Nb{sub 3}Sn strands for the International Thermo-nuclear Experimental Reactor are developed in Western Superconducting Technologies. Short cable-in-conduit conductors manufactured with these strands have been qualified. Mass production is accomplished, and all the performances of the strands meet the requirement of ITER project. Besides, more researches on the effect of strand design on critical current density and hysteresis loss for Nb{sub 3}Sn strands are carried out. It is found that critical current density can be enhanced by reducing filament diameter and increasing Sn content, and hysteresis loss of the strands can be significantly reduced through Cu split adopted in sub-element.

Investigating organic aerosol loading in the remote marine environment

Directory of Open Access Journals (Sweden)

K. Lapina

2011-09-01

Full Text Available Aerosol loading in the marine environment is investigated using aerosol composition measurements from several research ship campaigns (ICEALOT, MAP, RHaMBLe, VOCALS and OOMPH, observations of total AOD column from satellite (MODIS and ship-based instruments (Maritime Aerosol Network, MAN, and a global chemical transport model (GEOS-Chem. This work represents the most comprehensive evaluation of oceanic OM emission inventories to date, by employing aerosol composition measurements obtained from campaigns with wide spatial and temporal coverage. The model underestimates AOD over the remote ocean on average by 0.02 (21 %, compared to satellite observations, but provides an unbiased simulation of ground-based Maritime Aerosol Network (MAN observations. Comparison with cruise data demonstrates that the GEOS-Chem simulation of marine sulfate, with the mean observed values ranging between 0.22 μg m⁻³ and 1.34 μg m⁻³, is generally unbiased, however surface organic matter (OM concentrations, with the mean observed concentrations between 0.07 μg m⁻³ and 0.77 μg m⁻³, are underestimated by a factor of 2–5 for the standard model run. Addition of a sub-micron marine OM source of approximately 9 TgC yr⁻¹ brings the model into agreement with the ship-based measurements, however this additional OM source does not explain the model underestimate of marine AOD. The model underestimate of marine AOD is therefore likely the result of a combination of satellite retrieval bias and a missing marine aerosol source (which exhibits a different spatial pattern than existing aerosol in the model.

Research on marine and freshwater fish identification model based on hyper-spectral imaging technology

Science.gov (United States)

Fu, Yan; Guo, Pei-yuan; Xiang, Ling-zi; Bao, Man; Chen, Xing-hai

2013-08-01

With the gradually mature of hyper spectral image technology, the application of the meat nondestructive detection and recognition has become one of the current research focuses. This paper for the study of marine and freshwater fish by the pre-processing and feature extraction of the collected spectral curve data, combined with BP network structure and LVQ network structure, a predictive model of hyper spectral image data of marine and freshwater fish has been initially established and finally realized the qualitative analysis and identification of marine and freshwater fish quality. The results of this study show that hyper spectral imaging technology combined with the BP and LVQ Artificial Neural Network Model can be used for the identification of marine and freshwater fish detection. Hyper-spectral data acquisition can be carried out without any pretreatment of the samples, thus hyper-spectral imaging technique is the lossless, high- accuracy and rapid detection method for quality of fish. In this study, only 30 samples are used for the exploratory qualitative identification of research, although the ideal study results are achieved, we will further increase the sample capacity to take the analysis of quantitative identification and verify the feasibility of this theory.

Metallographic investigation of fracture behavior in ITER-style Nb$_{3}$Sn superconducting strands

CERN Document Server

Jewell, M C; Larbalestier, D C; Nijhuis, A

2009-01-01

In this work we specify the extent to which fracture in two ITER-style Nb$_{3}$Sn composite strands occurs in a collective or individual manner, under mechanical tension and bending from the TARSIS apparatus at the University of Twente. A bronze-route strand from European Advanced Superconductors (EAS), which has very uniform, well-spaced filaments, has a widely distributed (200 μm) fracture field and exhibits a composite of individual and collective cracks. An internal tin strand from Oxford Instruments – Superconducting Technology (OST) demonstrates much more localized, collective fracture behavior. The filaments in this strand are about four times larger (in area) than the filaments in the EAS strand, and also agglomerate significantly during heat treatment upon conversion of the Nb to Nb$_{3}$Sn. These results demonstrate that the architecture of the strand can play a significant role in determining the mechanical toughness of the composite, and that strand design should incorporate mechanical consider...

The Effect of Basepair Mismatch on DNA Strand Displacement.

Science.gov (United States)

Broadwater, D W Bo; Kim, Harold D

2016-04-12

DNA strand displacement is a key reaction in DNA homologous recombination and DNA mismatch repair and is also heavily utilized in DNA-based computation and locomotion. Despite its ubiquity in science and engineering, sequence-dependent effects of displacement kinetics have not been extensively characterized. Here, we measured toehold-mediated strand displacement kinetics using single-molecule fluorescence in the presence of a single basepair mismatch. The apparent displacement rate varied significantly when the mismatch was introduced in the invading DNA strand. The rate generally decreased as the mismatch in the invader was encountered earlier in displacement. Our data indicate that a single base pair mismatch in the invader stalls branch migration and displacement occurs via direct dissociation of the destabilized incumbent strand from the substrate strand. We combined both branch migration and direct dissociation into a model, which we term the concurrent displacement model, and used the first passage time approach to quantitatively explain the salient features of the observed relationship. We also introduce the concept of splitting probabilities to justify that the concurrent model can be simplified into a three-step sequential model in the presence of an invader mismatch. We expect our model to become a powerful tool to design DNA-based reaction schemes with broad functionality. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Microwave wood strand drying: energy consumption, VOC emission and drying quality

Energy Technology Data Exchange (ETDEWEB)

Wang, S.; Du, G.; Zhang, Y. [Tennessee Univ., Knoxville, TN (United States). Dept. of Forestry, Wildlife and Fisheries

2005-07-01

The objective of this research was to develop microwave drying technology for wood strand drying for oriented strand board (OSB) manufacturing. The advantages of microwave drying included a reduction in the drying time of wood strands and a reduction in the release of volatile organic compounds (VOC) through a decrease in the thermal degradation of the wood material. Temperature and moisture content changes under different microwave drying conditions were investigated. The effects of microwave drying on VOC emissions were evaluated and analyzed using gas chromatography and mass spectrometry. Microwave power input and the mass of drying materials in the microwave oven were found to have a dominant effect on drying quality. Results indicated that an increase in microwave power input and a decrease in sample weights resulted in high drying temperatures, short drying times and a high drying rate. The effect of microwave drying on the strand surfaces was also investigated. Different strand geometries and initial moisture content resulted in varying warm-up curves, but did not influence final moisture content. VOC emissions were quantified by comparing alpha-pinene concentrations. The microwave drying resulted in lower VOC emissions compared with conventional drying methods. It was concluded that the microwave drying technique provided faster strand drying and reduced energy consumption by up to 50 per cent. In addition, the surface wettability of wood strands dried with microwaves was better than with an industrial rotary drum drier. 12 refs., 3 tabs., 5 figs.

Toxin MqsR Cleaves Single-Stranded mRNA with Various 5 Ends

Science.gov (United States)

2016-08-24

either protein ORIGINAL RESEARCH Toxin MqsR cleaves single- stranded mRNA with various 5’ ends Nityananda Chowdhury1,*, Brian W. Kwan1,*, Louise C...in which a single 5′- GCU site was predicted to be single- stranded (ssRNA), double- stranded (dsRNA), in the loop of a stem - loop (slRNA), or in a...single- stranded 5′- GCU sites since cleavage was approximately 20- fold higher than cleavage seen with the 5′- GCU site in the stem - loop and

Rise and fall over 26 years of a marine epizootic in Hawaiian green sea turtles.

Science.gov (United States)

Chaloupka, Milani; Balazs, George H; Work, Thierry M

2009-10-01

Estimates of chronic disease prevalence are needed to improve our understanding of marine disease epizootiology, which is poorly known for marine megafauna such as marine turtles. An emerging worldwide threat to green sea turtles (Chelonia mydas) is fibropapillomatosis (FP), which is a pandemic tumor-forming disease associated with herpes-viruses. We report on a 26-yr FP epidemic in the Hawaiian Archipelago and show that apparent disease prevalence in the world's main endemic hot spot increased rapidly following a late 1980s outbreak, peaked during the mid-1990s, and then declined steadily ever since. While this disease is a major cause of sea turtle stranding in Hawaiian waters and can be fatal, we also show that long-term tumor regression can occur even for turtles with advanced FP. The endemic Hawaiian green turtle stock was severely depleted by overexploitation prior to protection under the US Endangered Species Act in 1978. This stock has increased significantly ever since, despite exposure to a major chronic disease epidemic that is currently declining.

World-Wide Benchmarking of ITER Nb$_{3}$Sn Strand Test Facilities

CERN Document Server

Jewell, MC; Takahashi, Yoshikazu; Shikov, Alexander; Devred, Arnaud; Vostner, Alexander; Liu, Fang; Wu, Yu; Jewell, Matthew C; Boutboul, Thierry; Bessette, Denis; Park, Soo-Hyeon; Isono, Takaaki; Vorobieva, Alexandra; Martovetsky, Nicolai; Seo, Kazutaka

2010-01-01

The world-wide procurement of Nb$_{3}$Sn and NbTi for the ITER superconducting magnet systems will involve eight to ten strand suppliers from six Domestic Agencies (DAs) on three continents. To ensure accurate and consistent measurement of the physical and superconducting properties of the composite strand, a strand test facility benchmarking effort was initiated in August 2008. The objectives of this effort are to assess and improve the superconducting strand test and sample preparation technologies at each DA and supplier, in preparation for the more than ten thousand samples that will be tested during ITER procurement. The present benchmarking includes tests for critical current (I-c), n-index, hysteresis loss (Q(hys)), residual resistivity ratio (RRR), strand diameter, Cu fraction, twist pitch, twist direction, and metal plating thickness (Cr or Ni). Nineteen participants from six parties (China, EU, Japan, South Korea, Russia, and the United States) have participated in the benchmarking. This round, cond...

Self-Field Effects in Magneto-Thermal Instabilities for Nb-Sn Strands

CERN Document Server

Bordini, B; Fehér, S; Rossi, L; Zlobin, A V

2008-01-01

Recent advancements in the critical current density (Jc) of Nb$_{3}$Sn conductors, coupled with a large effective filament size, have drawn attention to the problem of magnetothermal instabilities. At low magnetic fields, the quench current of such high Jc Nb$_{3}$Sn strands is significantly lower than their critical current because of the above-mentioned instabilities. An adiabatic model to calculate the minimum current at which a strand can quench due to magneto-thermal instabilities is developed. The model is based on an 'integral' approach already used elsewhere [1]. The main difference with respect to the previous model is the addition of the self-field effect that allows to describe premature quenches of non-magnetized Nb$_{3}$Sn strands and to better calculate the quench current of strongly magnetized strands. The model is in good agreement with experimental results at 4.2 K obtained at Fermilab using virgin Modified Jelly Roll (MJR) strands with a low Residual Resistivity Ratio (RRR) of the stabilizin...

Composition and potential origin of marine debris stranded in the Western Indian Ocean on remote Alphonse Island, Seychelles

International Nuclear Information System (INIS)

Duhec, Aurélie V.; Jeanne, Richard F.; Maximenko, Nikolai; Hafner, Jan

2015-01-01

The abundance, composition, and potential sources of marine debris were investigated on remote Alphonse Island, during the austral winter 2013. A total of 4743 items, weighing 142 kg, were removed from 1 km of windward beach, facing the prevailing southeasterly trade winds. Our study demonstrates the prevalence of plastic debris as a world-wide marine contaminant. Characteristics of the debris suggest it originated primarily from land-based sources. To determine their potential geographic sources we used the Surface Current from Diagnostic model of near-surface ocean currents, forced by satellite sea level and wind data. While preliminary evidence indicated the Southeast Asia to be the main source of the flotsam, the model highlighted Somalia as another potential primary source. Our study concludes that most of the collected debris entered the sea as a result of inadequate waste management and demonstrates how anthropogenic waste can negatively impact even the most remote environments

Entanglement effects in model polymer networks

Science.gov (United States)

Everaers, R.; Kremer, K.

The influence of topological constraints on the local dynamics in cross-linked polymer melts and their contribution to the elastic properties of rubber elastic systems are a long standing problem in statistical mechanics. Polymer networks with diamond lattice connectivity (Everaers and Kremer 1995, Everaers and Kremer 1996a) are idealized model systems which isolate the effect of topology conservation from other sources of quenched disorder. We study their behavior in molecular dynamics simulations under elongational strain. In our analysis we compare the measured, purely entropic shear moduli G to the predictions of statistical mechanical models of rubber elasticity, making extensive use of the microscopic structural and topological information available in computer simulations. We find (Everaers and Kremer 1995) that the classical models of rubber elasticity underestimate the true change in entropy in a deformed network significantly, because they neglect the tension along the contour of the strands which cannot relax due to entanglements (Everaers and Kremer (in preparation)). This contribution and the fluctuations in strained systems seem to be well described by the constrained mode model (Everaers 1998) which allows to treat the crossover from classical rubber elasticity to the tube model for polymer networks with increasing strand length within one transparant formalism. While this is important for the description of the effects we try to do a first quantitative step towards their explanation by topological considerations. We show (Everaers and Kremer 1996a) that for the comparatively short strand lengths of our diamond networks the topology contribution to the shear modulus is proportional to the density of entangled mesh pairs with non-zero Gauss linking number. Moreover, the prefactor can be estimated consistently within a rather simple model developed by Vologodskii et al. and by Graessley and Pearson, which is based on the definition of an entropic

Shear-wave velocity of marine sediments offshore Taiwan using ambient seismic noise

Science.gov (United States)

Lin, Yu-Tse; Lin, Jing-Yi; Kuo-Chen, Hao; Yeh, Yi-Chin; Cheng, Win-Bin

2017-04-01

Seismic ambient noise technology has many advantages over the traditional two-station method. The most important one is that noise is happening all the time and it can be widely and evenly distributed. Thus, the Green's Function of any station pair can be obtained through the data cross-correlation process. Many related studies have been performed to estimate the velocity structures based on the inland area. Only a few studies were reported for the marine area due to the relatively shorter recording time of ocean bottom seismometers (OBS) deployment and the high cost of the marine experiment. However, the understanding about the shear-wave velocity (Vs) of the marine sediments is very crucial for the hazard assessment related to submarine landslides, particularly with the growing of submarine resources exploration. In this study, we applied the ambient noise technique to four OBS seismic networks located offshore Taiwan in the aim of getting more information about the noise sources and having the preliminary estimation for the Vs of the marine sediments. Two of the seismic networks were deployed in the NE part of Taiwan, near the Ryukyu subduction system, whereas the others were in the SW area, on the continental margin rich in gas hydrate. Generally, ambient seismic noise could be associated with wind, ocean waves, rock fracturing and anthropogenic activity. In the southwestern Taiwan, the cross-correlation function obtained from two seismic networks indicate similar direction, suggestion that the source from the south part of the network could be the origin of the noise. However, the two networks in the northeastern Taiwan show various source direction, which could be caused by the abrupt change of bathymetry or the volcanic degassing effect frequently observed by the marine geophysical method in the area. The Vs determined from the dispersion curve shows a relatively higher value for the networks in the Okinawa Trough (OT) off NE Taiwan than that in the

To Eat or Not to Eat? Debris Selectivity by Marine Turtles

Science.gov (United States)

Schuyler, Qamar; Hardesty, Britta Denise; Wilcox, Chris; Townsend, Kathy

2012-01-01

Marine debris is a growing problem for wildlife, and has been documented to affect more than 267 species worldwide. We investigated the prevalence of marine debris ingestion in 115 sea turtles stranded in Queensland between 2006–2011, and assessed how the ingestion rates differ between species (Eretmochelys imbricata vs. Chelonia mydas) and by turtle size class (smaller oceanic feeders vs. larger benthic feeders). Concurrently, we conducted 25 beach surveys to estimate the composition of the debris present in the marine environment. Based on this proxy measurement of debris availability, we modeled turtles’ debris preferences (color and type) using a resource selection function, a method traditionally used for habitat and food selection. We found no significant difference in the overall probability of ingesting debris between the two species studied, both of which have similar life histories. Curved carapace length, however, was inversely correlated with the probability of ingesting debris; 54.5% of pelagic sized turtles had ingested debris, whereas only 25% of benthic feeding turtles were found with debris in their gastrointestinal system. Benthic and pelagic sized turtles also exhibited different selectivity ratios for debris ingestion. Benthic phase turtles had a strong selectivity for soft, clear plastic, lending support to the hypothesis that sea turtles ingest debris because it resembles natural prey items such as jellyfish. Pelagic turtles were much less selective in their feeding, though they showed a trend towards selectivity for rubber items such as balloons. Most ingested items were plastic and were positively buoyant. This study highlights the need to address increasing amounts of plastic in the marine environment, and provides evidence for the disproportionate ingestion of balloons by marine turtles. PMID:22829894

To eat or not to eat? Debris selectivity by marine turtles.

Directory of Open Access Journals (Sweden)

Qamar Schuyler

Full Text Available Marine debris is a growing problem for wildlife, and has been documented to affect more than 267 species worldwide. We investigated the prevalence of marine debris ingestion in 115 sea turtles stranded in Queensland between 2006-2011, and assessed how the ingestion rates differ between species (Eretmochelys imbricata vs. Chelonia mydas and by turtle size class (smaller oceanic feeders vs. larger benthic feeders. Concurrently, we conducted 25 beach surveys to estimate the composition of the debris present in the marine environment. Based on this proxy measurement of debris availability, we modeled turtles' debris preferences (color and type using a resource selection function, a method traditionally used for habitat and food selection. We found no significant difference in the overall probability of ingesting debris between the two species studied, both of which have similar life histories. Curved carapace length, however, was inversely correlated with the probability of ingesting debris; 54.5% of pelagic sized turtles had ingested debris, whereas only 25% of benthic feeding turtles were found with debris in their gastrointestinal system. Benthic and pelagic sized turtles also exhibited different selectivity ratios for debris ingestion. Benthic phase turtles had a strong selectivity for soft, clear plastic, lending support to the hypothesis that sea turtles ingest debris because it resembles natural prey items such as jellyfish. Pelagic turtles were much less selective in their feeding, though they showed a trend towards selectivity for rubber items such as balloons. Most ingested items were plastic and were positively buoyant. This study highlights the need to address increasing amounts of plastic in the marine environment, and provides evidence for the disproportionate ingestion of balloons by marine turtles.

On the biophysics and kinetics of toehold-mediated DNA strand displacement.

Science.gov (United States)

Srinivas, Niranjan; Ouldridge, Thomas E; Sulc, Petr; Schaeffer, Joseph M; Yurke, Bernard; Louis, Ard A; Doye, Jonathan P K; Winfree, Erik

2013-12-01

Dynamic DNA nanotechnology often uses toehold-mediated strand displacement for controlling reaction kinetics. Although the dependence of strand displacement kinetics on toehold length has been experimentally characterized and phenomenologically modeled, detailed biophysical understanding has remained elusive. Here, we study strand displacement at multiple levels of detail, using an intuitive model of a random walk on a 1D energy landscape, a secondary structure kinetics model with single base-pair steps and a coarse-grained molecular model that incorporates 3D geometric and steric effects. Further, we experimentally investigate the thermodynamics of three-way branch migration. Two factors explain the dependence of strand displacement kinetics on toehold length: (i) the physical process by which a single step of branch migration occurs is significantly slower than the fraying of a single base pair and (ii) initiating branch migration incurs a thermodynamic penalty, not captured by state-of-the-art nearest neighbor models of DNA, due to the additional overhang it engenders at the junction. Our findings are consistent with previously measured or inferred rates for hybridization, fraying and branch migration, and they provide a biophysical explanation of strand displacement kinetics. Our work paves the way for accurate modeling of strand displacement cascades, which would facilitate the simulation and construction of more complex molecular systems.

The role of cytosine methylation on charge transport through a DNA strand

Energy Technology Data Exchange (ETDEWEB)

Qi, Jianqing, E-mail: jqqi@uw.edu; Anantram, M. P., E-mail: anantmp@uw.edu [Department of Electrical Engineering, University of Washington, Seattle, Washington 98195-2500 (United States); Govind, Niranjan, E-mail: niri.govind@pnnl.gov [William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States)

2015-09-07

Cytosine methylation has been found to play a crucial role in various biological processes, including a number of human diseases. The detection of this small modification remains challenging. In this work, we computationally explore the possibility of detecting methylated DNA strands through direct electrical conductance measurements. Using density functional theory and the Landauer-Büttiker method, we study the electronic properties and charge transport through an eight base-pair methylated DNA strand and its native counterpart. We first analyze the effect of cytosine methylation on the tight-binding parameters of two DNA strands and then model the transmission of the electrons and conductance through the strands both with and without decoherence. We find that the main difference of the tight-binding parameters between the native DNA and the methylated DNA lies in the on-site energies of (methylated) cytosine bases. The intra- and inter-strand hopping integrals between two nearest neighboring guanine base and (methylated) cytosine base also change with the addition of the methyl groups. Our calculations show that in the phase-coherent limit, the transmission of the methylated strand is close to the native strand when the energy is nearby the highest occupied molecular orbital level and larger than the native strand by 5 times in the bandgap. The trend in transmission also holds in the presence of the decoherence with the same rate. The lower conductance for the methylated strand in the experiment is suggested to be caused by the more stable structure due to the introduction of the methyl groups. We also study the role of the exchange-correlation functional and the effect of contact coupling by choosing coupling strengths ranging from weak to strong coupling limit.

Radionuclides in marine mammals off the Portuguese coast

International Nuclear Information System (INIS)

Malta, Margarida; Carvalho, Fernando P.

2011-01-01

Radionuclide analyses were performed in tissue samples including muscle, gonad, liver, mammary gland, and bone of marine mammals stranded on the Portuguese west coast during January-July 2006. Tissues were collected from seven dolphins (Delphinus delphis and Stenella coeruleoalba) and one pilot whale (Globicephala sp.). Samples were analyzed for 210 Po and 210 Pb by alpha spectrometry and for 137 Cs and 40 K by gamma spectrometry. Po-210 concentrations in common dolphin's muscle (D. delphis) averaged 56 ± 32 Bq kg -1 wet weight (w.w.), while 210 Pb averaged 0.17 ± 0.07 Bq kg -1 w.w., 137 Cs averaged 0.29 ± 0.28 Bq kg -1 w.w., and 40 K 129 ± 48 Bq kg -1 w.w. Absorbed radiation doses due to these radionuclides for the internal organs of common dolphins were computed and attained a 1.50 μGy h -1 on a whole body basis. 210 Po was the main contributor to the weighted absorbed dose, accounting for 97% of the dose from internally accumulated radionuclides. These computed radiation doses in dolphins are compared to radiation doses from 210 Po and other radionuclides reported for human tissues. Due to the high 210 Po activity concentration in dolphins, the internal radiation dose in these marine mammals is about three orders of magnitude higher than in man. - Highlights: → In marine mammals the highest activity concentrations were those of 40 K and 210 Po. → Absorbed radiation doses in dolphin tissues attained 1.50 mGy h -1 on a whole body basis. → Po-210 was the main contributor (97%) to the internal absorbed radiation dose. → The high 210 Po concentration in the marine mammal's tissues is due to food chain transfer. → The absorbed radiation dose in dolphins is three orders of magnitude higher than in man.

Ketahanan Papan Unting (Oriented Strand Board) terhadap Serangan Rayap Tanah dan Rayap Kayu Kering

OpenAIRE

Gea, Bud diman

2011-01-01

Oriented strand board is panel of wood raw material from which strand composed of cross and upright structure. In order to oriented strand board can be used for interior and exterior needs, than necessary to be applied various thenology of quality improvement like durabelities and endurance of oriented strand board. For it does found endurance oriented strand board from attack of ground termite and wood dry termite, necessary doing grave yard trial and wood dry termite trial. This research ta...

Conservation of the Critically Endangered Eastern Australian Population of the Grey Nurse Shark ( Carcharias taurus) Through Cross-Jurisdictional Management of a Network of Marine-Protected Areas

Science.gov (United States)

Lynch, Tim P.; Harcourt, Robert; Edgar, Graham; Barrett, Neville

2013-12-01

Between 2001 and 2009, 26 marine-protected areas (MPA) were established on the east Australian seaboard, at least in part, to manage human interactions with a critically endangered population of grey nurse shark, Carcharias taurus. This network is spread across six MPA systems and includes all 19 sites outlined in the National Recovery Plan for C. taurus, though five sites remain open to some forms of fishing. The reserve network has complex cross-jurisdictional management, as the sharks occur in waters controlled by the Australian states of New South Wales (NSW) and Queensland, as well as by the Commonwealth (Federal) government. Jurisdiction is further complicated by fisheries and conservation departments both engaging in management activities within each state. This has resulted in protected area types that include IUCN category II equivalent zones in NSW, Queensland, and Commonwealth marine parks that either overlay or complement another large scaled network of protected sites called critical habitats. Across the network, seven and eight rule permutations for diving and fishing, respectively, are applied to this population of sharks. Besides sites identified by the recovery plan, additional sites have been protected as part of the general development of MPA networks. A case study at one of these sites, which historically was known to be occupied by C. taurus but had been abandoned, appears to shows re-establishment of an aggregation of juvenile and sub-adult sharks. Concurrent with the re-establishment of the aggregation, a local dive operator increased seasonal dive visitation rates at the site fourfold. As a precautionary measure, protection of abandoned sites, which includes nursery and gestating female habitats are options that may assist recovery of the east coast population of C. taurus.

Higher 5-hydroxymethylcytosine identifies immortal DNA strand chromosomes in asymmetrically self-renewing distributed stem cells.

Science.gov (United States)

Huh, Yang Hoon; Cohen, Justin; Sherley, James L

2013-10-15

Immortal strands are the targeted chromosomal DNA strands of nonrandom sister chromatid segregation, a mitotic chromosome segregation pattern unique to asymmetrically self-renewing distributed stem cells (DSCs). By nonrandom segregation, immortal DNA strands become the oldest DNA strands in asymmetrically self-renewing DSCs. Nonrandom segregation of immortal DNA strands may limit DSC mutagenesis, preserve DSC fate, and contribute to DSC aging. The mechanisms responsible for specification and maintenance of immortal DNA strands are unknown. To discover clues to these mechanisms, we investigated the 5-methylcytosine and 5-hydroxymethylcytosine (5hmC) content on chromosomes in mouse hair follicle DSCs during nonrandom segregation. Although 5-methylcytosine content did not differ significantly, the relative content of 5hmC was significantly higher in chromosomes containing immortal DNA strands than in opposed mitotic chromosomes containing younger mortal DNA strands. The difference in relative 5hmC content was caused by the loss of 5hmC from mortal chromosomes. These findings implicate higher 5hmC as a specific molecular determinant of immortal DNA strand chromosomes. Because 5hmC is an intermediate during DNA demethylation, we propose a ten-eleven translocase enzyme mechanism for both the specification and maintenance of nonrandomly segregated immortal DNA strands. The proposed mechanism reveals a means by which DSCs "know" the generational age of immortal DNA strands. The mechanism is supported by molecular expression data and accounts for the selection of newly replicated DNA strands when nonrandom segregation is initiated. These mechanistic insights also provide a possible basis for another characteristic property of immortal DNA strands, their guanine ribonucleotide dependency.

Population Connectivity Measures of Fishery-Targeted Coral Reef Species to Inform Marine Reserve Network Design in Fiji.

Science.gov (United States)

Eastwood, Erin K; López, Elora H; Drew, Joshua A

2016-01-25

Coral reef fish serve as food sources to coastal communities worldwide, yet are vulnerable to mounting anthropogenic pressures like overfishing and climate change. Marine reserve networks have become important tools for mitigating these pressures, and one of the most critical factors in determining their spatial design is the degree of connectivity among different populations of species prioritized for protection. To help inform the spatial design of an expanded reserve network in Fiji, we used rapidly evolving mitochondrial genes to investigate connectivity patterns of three coral reef species targeted by fisheries in Fiji: Epinephelus merra (Serranidae), Halichoeres trimaculatus (Labridae), and Holothuria atra (Holothuriidae). The two fish species, E. merra and Ha. trimaculatus, exhibited low genetic structuring and high amounts of gene flow, whereas the sea cucumber Ho. atra displayed high genetic partitioning and predominantly westward gene flow. The idiosyncratic patterns observed among these species indicate that patterns of connectivity in Fiji are likely determined by a combination of oceanographic and ecological characteristics. Our data indicate that in the cases of species with high connectivity, other factors such as representation or political availability may dictate where reserves are placed. In low connectivity species, ensuring upstream and downstream connections is critical.

Tolerance of DNA Mismatches in Dmc1 Recombinase-mediated DNA Strand Exchange*

Science.gov (United States)

Borgogno, María V.; Monti, Mariela R.; Zhao, Weixing; Sung, Patrick; Argaraña, Carlos E.; Pezza, Roberto J.

2016-01-01

Recombination between homologous chromosomes is required for the faithful meiotic segregation of chromosomes and leads to the generation of genetic diversity. The conserved meiosis-specific Dmc1 recombinase catalyzes homologous recombination triggered by DNA double strand breaks through the exchange of parental DNA sequences. Although providing an efficient rate of DNA strand exchange between polymorphic alleles, Dmc1 must also guard against recombination between divergent sequences. How DNA mismatches affect Dmc1-mediated DNA strand exchange is not understood. We have used fluorescence resonance energy transfer to study the mechanism of Dmc1-mediated strand exchange between DNA oligonucleotides with different degrees of heterology. The efficiency of strand exchange is highly sensitive to the location, type, and distribution of mismatches. Mismatches near the 3′ end of the initiating DNA strand have a small effect, whereas most mismatches near the 5′ end impede strand exchange dramatically. The Hop2-Mnd1 protein complex stimulates Dmc1-catalyzed strand exchange on homologous DNA or containing a single mismatch. We observed that Dmc1 can reject divergent DNA sequences while bypassing a few mismatches in the DNA sequence. Our findings have important implications in understanding meiotic recombination. First, Dmc1 acts as an initial barrier for heterologous recombination, with the mismatch repair system providing a second level of proofreading, to ensure that ectopic sequences are not recombined. Second, Dmc1 stepping over infrequent mismatches is likely critical for allowing recombination between the polymorphic sequences of homologous chromosomes, thus contributing to gene conversion and genetic diversity. PMID:26709229

Composition and potential origin of marine debris stranded in the Western Indian Ocean on remote Alphonse Island, Seychelles.

Science.gov (United States)

Duhec, Aurélie V; Jeanne, Richard F; Maximenko, Nikolai; Hafner, Jan

2015-07-15

The abundance, composition, and potential sources of marine debris were investigated on remote Alphonse Island, during the austral winter 2013. A total of 4743 items, weighing 142 kg, were removed from 1 km of windward beach, facing the prevailing southeasterly trade winds. Our study demonstrates the prevalence of plastic debris as a world-wide marine contaminant. Characteristics of the debris suggest it originated primarily from land-based sources. To determine their potential geographic sources we used the Surface Current from Diagnostic model of near-surface ocean currents, forced by satellite sea level and wind data. While preliminary evidence indicated the Southeast Asia to be the main source of the flotsam, the model highlighted Somalia as another potential primary source. Our study concludes that most of the collected debris entered the sea as a result of inadequate waste management and demonstrates how anthropogenic waste can negatively impact even the most remote environments. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Checkpoint Kinase Rad53 Couples Leading- and Lagging-Strand DNA Synthesis under Replication Stress.

Science.gov (United States)

Gan, Haiyun; Yu, Chuanhe; Devbhandari, Sujan; Sharma, Sushma; Han, Junhong; Chabes, Andrei; Remus, Dirk; Zhang, Zhiguo

2017-10-19

The checkpoint kinase Rad53 is activated during replication stress to prevent fork collapse, an essential but poorly understood process. Here we show that Rad53 couples leading- and lagging-strand synthesis under replication stress. In rad53-1 cells stressed by dNTP depletion, the replicative DNA helicase, MCM, and the leading-strand DNA polymerase, Pol ε, move beyond the site of DNA synthesis, likely unwinding template DNA. Remarkably, DNA synthesis progresses further along the lagging strand than the leading strand, resulting in the exposure of long stretches of single-stranded leading-strand template. The asymmetric DNA synthesis in rad53-1 cells is suppressed by elevated levels of dNTPs in vivo, and the activity of Pol ε is compromised more than lagging-strand polymerase Pol δ at low dNTP concentrations in vitro. Therefore, we propose that Rad53 prevents the generation of excessive ssDNA under replication stress by coordinating DNA unwinding with synthesis of both strands. Copyright © 2017 Elsevier Inc. All rights reserved.

Estimation of Prestress Force Distribution in the Multi-Strand System of Prestressed Concrete Structures

Directory of Open Access Journals (Sweden)

Keunhee Cho

2015-06-01

Full Text Available Prestressed concrete (PSC is one of the most reliable, durable and widely used construction materials, which overcomes the weakness of concrete in tension by the introduction of a prestress force. Smart strands enabling measurement of the prestress force have recently been developed to maintain PSC structures throughout their lifetime. However, the smart strand cannot give a representative indication of the whole prestress force when used in multi-strand systems since each strand sustains a different prestress force. In this paper, the actual distribution of the prestress force in a multi-strand system is examined using elastomagnetic (EM sensors to develop a method for tracking representative indicators of the prestress force using smart strands.

Estimation of Prestress Force Distribution in the Multi-Strand System of Prestressed Concrete Structures.

Science.gov (United States)

Cho, Keunhee; Park, Sung Yong; Cho, Jeong-Rae; Kim, Sung Tae; Park, Young-Hwan

2015-06-15

Prestressed concrete (PSC) is one of the most reliable, durable and widely used construction materials, which overcomes the weakness of concrete in tension by the introduction of a prestress force. Smart strands enabling measurement of the prestress force have recently been developed to maintain PSC structures throughout their lifetime. However, the smart strand cannot give a representative indication of the whole prestress force when used in multi-strand systems since each strand sustains a different prestress force. In this paper, the actual distribution of the prestress force in a multi-strand system is examined using elastomagnetic (EM) sensors to develop a method for tracking representative indicators of the prestress force using smart strands.

DNA strand breakage repair in ataxia telangiectasia fibroblast-like cells

Energy Technology Data Exchange (ETDEWEB)

Vincent, Jr, R A; Sheridan, III, R B; Huang, P C [Johns Hopkins Univ., Baltimore, Md. (USA). Dept. of Environmental and Biophysical Sciences

1975-12-01

Human diploid fibroblast-like cells derived from four patients with the genetic disease ataxia telangiectasia and from two non-mutant donors were examined for the repair of x-ray induced strand breaks in DNA. The ataxia telangiectasia cultures showed no significant differences from the non-mutant cultures in the kinetics and extent of strand repair. This suggests that the increased spontaneous and x-ray induced chromatid aberrations observed in ataxia telangiectasia cells are not caused by a defect in the repair of single strand breaks as might be suspected from a general model of aberration production.

Survey of stranded gas and delivered costs to Europe of selected gas resources

Science.gov (United States)

Attanasi, E.D.; Freeman, P.A.

2011-01-01

Two important trends affecting the expected growth of global gas markets are (1) the shift by many industrialized countries from coal-fired electricity generation to the use of natural gas to generate electricity and (2) the industrialization of the heavily populated Asian countries of India and China. This paper surveys discovered gas in stranded conventional gas accumulations and presents estimates of the cost of developing and producing stranded gas in selected countries. Stranded gas is natural gas in discovered or identified fields that is not currently commercially producible for either physical or economic reasons. Published reserves of gas at the global level do not distinguish between volumes of gas in producing fields and volumes in nonproducing fields. Data on stranded gas reported here-that is the volumes, geographical distribution, and size distributions of stranded gas fields at the country and regional level-are based on the examination of individual-field data and represent a significant improvement in information available to industry and government decision makers. Globally, stranded gas is pervasive, but large volumes in large accumulations are concentrated in only a few areas. The cost component of the paper focuses on stranded conventional gas accumulations in Africa and South America that have the potential to augment supplies to Europe. The methods described for the computation of extraction and transport costs are innovative in that they use information on the sizes and geographical distribution of the identified stranded gas fields. The costs are based on industry data specific to the country and geologic basin where the stranded gas is located. Gas supplies to Europe can be increased significantly at competitive costs by the development of stranded gas. Net extraction costs of producing the identified gas depend critically on the natural-gas-liquids (NGLs) content, the prevailing prices of liquids, the size of the gas accumulation, and the

Youth Science Ambassadors: Connecting Indigenous communities with Ocean Networks Canada tools to inspire future ocean scientists and marine resource managers

Science.gov (United States)

Pelz, M.; Hoeberechts, M.; Hale, C.; McLean, M. A.

2017-12-01

This presentation describes Ocean Networks Canada's (ONC) Youth Science Ambassador Program. The Youth Science Ambassadors are a growing network of youth in Canadian coastal communities whose role is to connect ocean science, ONC data, and Indigenous knowledge. By directly employing Indigenous youth in communities in which ONC operates monitoring equipment, ONC aims to encourage wider participation and interest in ocean science and exploration. Further, the Youth Science Ambassadors act as role models and mentors to other local youth by highlighting connections between Indigenous and local knowledge and current marine science efforts. Ocean Networks Canada, an initiative of the University of Victoria, develops, operates, and maintains cabled ocean observatory systems. These include technologies developed on the world-leading NEPTUNE and VENUS observatories as well as community observatories in the Arctic and coastal British Columbia. These observatories, large and small, enable communities, users, scientists, teachers, and students to monitor real-time and historical data from the local marine environment from anywhere on the globe. Youth Science Ambassadors are part of the Learning and Engagement team whose role includes engaging Indigenous communities and schools in ocean science through ONC's K-12 Ocean Sense education program. All of the data collected by ONC are freely available over the Internet for non-profit use, including disaster planning, community-based decision making, and education. The Youth Science Ambassadors support collaboration with Indigenous communities and schools by facilitating educational programming, encouraging participation in ocean data collection and analysis, and fostering interest in ocean science. In addition, the Youth Science Ambassadors support community collaboration in decision-making for instrument deployment locations and identify ways in which ONC can help to address any areas of concern raised by the community. This

Knotting probabilities after a local strand passage in unknotted self-avoiding polygons

International Nuclear Information System (INIS)

Szafron, M L; Soteros, C E

2011-01-01

We investigate, both theoretically and numerically, the knotting probabilities after a local strand passage is performed in an unknotted self-avoiding polygon (SAP) on the simple cubic lattice. In the polygons studied, it is assumed that two polygon segments have already been brought close together for the purpose of performing a strand passage. This restricts the polygons considered to those that contain a specific pattern called Θ at a fixed location; an unknotted polygon containing Θ is called a Θ-SAP. It is proved that the number of n-edge Θ-SAPs grows exponentially (with n) at the same rate as the total number of n-edge unknotted SAPs (those with no prespecified strand passage structure). Furthermore, it is proved that the same holds for subsets of n-edge Θ-SAPs that yield a specific after-strand-passage knot-type. Thus, the probability of a given after-strand-passage knot-type does not grow (or decay) exponentially with n. Instead, it is conjectured that these after-strand-passage knot probabilities approach, as n goes to infinity, knot-type dependent amplitude ratios lying strictly between 0 and 1. This conjecture is supported by numerical evidence from Monte Carlo data generated using a composite (aka multiple) Markov chain Monte Carlo BFACF algorithm developed to study Θ-SAPs. A new maximum likelihood method is used to estimate the critical exponents relevant to this conjecture. We also obtain strong numerical evidence that the after-strand-passage knotting probability depends on the local structure around the strand-passage site. If the local structure and the crossing sign at the strand-passage site are considered, then we observe that the more 'compact' the local structure, the less likely the after-strand-passage polygon is to be knotted. This trend for compactness versus knotting probability is consistent with results obtained for other strand-passage models; however, we are the first to note the influence of the crossing-sign information. We

50 CFR 222.310 - Permit authority for designated agents and employees of specified Federal and state agencies.

Science.gov (United States)

2010-10-01

... stranded endangered sea turtles, and to salvage, collect data from, and dispose of, dead carcasses of endangered sea turtles in the marine environment. For purposes of this section, 'stranded' means endangered... member of any endangered species of sea turtle is found stranded or dead in the marine environment, any...

Oriented-strand-board- the wave of the future- for the building trade

Science.gov (United States)

Linda Ashton

1984-01-01

Move over, plywood. Oriented-strand board is here. It's less expensive. It's as durable. It has as many uses. And it is the wave of the future. "Oriented-strand board is a direct substitute for plywood" said Jerry Buckner, plant manager for the Martco oriented-strand board plant in Lemoyen. OSB, as it is commonly called, is a structural panel made...

75 FR 62820 - Screening Framework Guidance for Providers of Synthetic Double-Stranded DNA

Science.gov (United States)

2010-10-13

... Providers of Synthetic Double- Stranded DNA AGENCY: Department of Health and Human Services, Office of the.... Government has developed Guidance that provides a framework for screening synthetic double-stranded DNA (dsDNA). This document, the Screening Framework Guidance for Providers of Synthetic Double-Stranded DNA...

Stress-rupture lifetimes of organic fiber-epoxy strands and pressure vessels

International Nuclear Information System (INIS)

Hahn, H.T.; Chiu, I.L.; Gates, T.L.

1979-01-01

Long-term behavior of filament-wound pressure vessels were tested, Kevlar 49 epoxy strands were studied in stress-rupture for more than a year. Because the strands are the smallest structural unit in filament winding, their behavior directly controls the performance of vessels. Five different stress levels were studied: 86, 80, 74, 68, and 50% of the mean ultimate tensile strength (UTS). At each stress level, approximately one-hundred strands were hung in a room maintained at 22 to 24 0 C and below 20% relative humidity. Failure times were automatically recorded by a data acquisition system. Lifetimes were analyzed statistically using a two-parameter Weibull distribution. The maximum-likelihood method was used to estimate the parameters. The shape parameter, which is a measure of scatter and failure-rate change, increased with decreasing stress level. Less scatter and increasing failure rates were observed at lower stresses. There was no sign of an endurance limit down to 68% UTS. At 50% UTS no failure had yet occurred after 9000 h. The strand data were compared with data on lifetimes of pressure vessels wound with the same fiber and epoxy. The strands had slightly longer characteristic lifetimes, except at 86% UTS, and slightly less scatter, except at 68% UTS. The results of this study indicate that strands can provide valuable information about the long-term performance of filament-wound pressure vessels

Transformation of Saccharomyces cerevisiae with UV-irradiated single-stranded plasmid.

Science.gov (United States)

Zgaga, Z

1991-08-01

UV-irradiated single-stranded replicative plasmids were used to transform different yeast strains. The low doses of UV used in this study (10-75 J/m2) caused a significant decrease in the transforming efficiency of plasmid DNA in the Rad+ strain, while they had no effect on transformation with double-stranded plasmids of comparable size. Neither the rev3 mutation, nor the rad18 or rad52 mutations influenced the efficiency of transformation with irradiated single-stranded plasmid. However, it was found to be decreased in the double rev3 rad52 mutant. Extracellular irradiation of plasmid that contains both URA3 and LEU2 genes (psLU) gave rise to up to 5% Leu- transformants among selected Ura+ ones in the repair-proficient strain. Induction of Leu- transformants was dose-dependent and only partially depressed in the rev3 mutant. These results suggest that both mutagenic and recombinational repair processes operate on UV-damaged single-stranded DNA in yeast.

Durability of precast prestressed concrete piles in marine environment, part 2. Volume 2 : stainless steel prestressing strand and wire.

Science.gov (United States)

2012-06-01

The overall purpose of this research was to determine methods which may be applied : economically to mitigate corrosion of reinforcement in precast prestressed concrete piles in : Georgias marine environments. The research was divided into two par...

Metallographic autopsies of full-scale ITER prototype cable-in-conduit conductors after full cyclic testing in SULTAN: II. Significant reduction of strand movement and strand damage in short twist pitch CICCs

International Nuclear Information System (INIS)

Sanabria, Carlos; Lee, Peter J; Starch, William; Larbalestier, David C; Devred, Arnaud

2015-01-01

Prototype cable-in-conduit-conductors (CICCs) destined for use in the toroidal field and central solenoid coils of the ITER experimental fusion reactor underwent severe cyclic loading in the SULTAN facility. Their autopsies revealed significant and permanent transverse strand migration due to the large Lorentz forces of the SULTAN test. The movement resulted in a 3%–7% void fraction increase on the low pressure (LP) side of the longer twist pitch CICCs. However, short twist pitch conductors exhibited less than 1% void fraction increase in the LP side, as well as a complete absence of the Nb 3 Sn filament fractures observed in the longer twist pitch conductors. We report here a detailed strand-to-cable analysis of short and longer ‘baseline’ twist pitch CICCs. It was found that the use of internal tin (IT) strands in the longer ‘baseline’ twist pitch CICCs can be beneficial possibly because of their superior stiffness—which better resist strand movement—while the use of bronze process strands showed more movement and poorer cyclic test performance. This was not the case for the short twist pitch CICC. Such conductor design seems to work well with both strand types. But it was found that despite the absence of filament fractures, the short twist pitch CICC made from the IT strands studied here developed severe strand distortion during cabling which resulted in diffusion barrier breaks and Sn contamination of the Cu stabilizer during the heat treatment. Conversely, the short twist pitch CICC made from bronze process strands preserved diffusion barrier integrity. (paper)

Late Quaternary slip history of the Mill Creek strand of the San Andreas fault in San Gorgonio Pass, southern California: The role of a subsidiary left-lateral fault in strand switching

Science.gov (United States)

Kendrick, Katherine J.; Matti, Jonathan; Mahan, Shannon

2015-01-01

The fault history of the Mill Creek strand of the San Andreas fault (SAF) in the San Gorgonio Pass region, along with the reconstructed geomorphology surrounding this fault strand, reveals the important role of the left-lateral Pinto Mountain fault in the regional fault strand switching. The Mill Creek strand has 7.1–8.7 km total slip. Following this displacement, the Pinto Mountain fault offset the Mill Creek strand 1–1.25 km, as SAF slip transferred to the San Bernardino, Banning, and Garnet Hill strands. An alluvial complex within the Mission Creek watershed can be linked to palinspastic reconstruction of drainage segments to constrain slip history of the Mill Creek strand. We investigated surface remnants through detailed geologic mapping, morphometric and stratigraphic analysis, geochronology, and pedogenic analysis. The degree of soil development constrains the duration of surface stability when correlated to other regional, independently dated pedons. This correlation indicates that the oldest surfaces are significantly older than 500 ka. Luminescence dates of 106 ka and 95 ka from (respectively) 5 and 4 m beneath a younger fan surface are consistent with age estimates based on soil-profile development. Offset of the Mill Creek strand by the Pinto Mountain fault suggests a short-term slip rate of ∼10–12.5 mm/yr for the Pinto Mountain fault, and a lower long-term slip rate. Uplift of the Yucaipa Ridge block during the period of Mill Creek strand activity is consistent with thermochronologic modeled uplift estimates.

Workshop on effects of chromium coating on Nb3Sn superconductor strand: Proceedings

International Nuclear Information System (INIS)

1994-01-01

This report discusses the following topics: Chromium coating on superconductor strand -- an overview; technology of chromium plating; comparison of wires plated by different platers; search for chromium in copper; strand manufactures' presentations; chromium plating at the Lawrence Livermore National Laboratory; a first look at a chromium plating process development project tailored for T.P.X. and I.T.E.R. strand; and influence of chromium diffusion and related phenomena on the reference ratios of bare and chromium plated Nb 3 Sn strand

How many marine aliens in Europe?

Directory of Open Access Journals (Sweden)

Stelios Katsanevakis

2013-01-01

Full Text Available In the framework of the European Alien Species Information Network (EASIN; http://easin.jrc.ec.europa.eu/, an inventory of marine alienspecies in Europe was created by critically reviewing existing information in 34 global, European, regional and national databases. In total, 1369 marine alien species have been reported in the European seas (including 110 cryptogenic and 139 questionable species; this is a substantial increase from the 737 species previously reported in 2009 based on the DAISIE (Delivering Alien Invasive Species Inventories for Europe; http://www.europe-aliens.org dataset. Most of the reported species were invertebrates (63.3%, followed by chromists (13.7%, vertebrates (11.6%, and plants (10.1%. Mollusca is the most numerous phylum, followed by Arthropoda, Chordata, and Annelida. Thecountries with the highest reported numbers of marine alien species were Israel, Turkey, Italy, France, Egypt and Greece. A reporting bias is evident as efforts for monitoring and reporting alien species vary among countries.

Tolerance of DNA Mismatches in Dmc1 Recombinase-mediated DNA Strand Exchange.

Science.gov (United States)

Borgogno, María V; Monti, Mariela R; Zhao, Weixing; Sung, Patrick; Argaraña, Carlos E; Pezza, Roberto J

2016-03-04

Recombination between homologous chromosomes is required for the faithful meiotic segregation of chromosomes and leads to the generation of genetic diversity. The conserved meiosis-specific Dmc1 recombinase catalyzes homologous recombination triggered by DNA double strand breaks through the exchange of parental DNA sequences. Although providing an efficient rate of DNA strand exchange between polymorphic alleles, Dmc1 must also guard against recombination between divergent sequences. How DNA mismatches affect Dmc1-mediated DNA strand exchange is not understood. We have used fluorescence resonance energy transfer to study the mechanism of Dmc1-mediated strand exchange between DNA oligonucleotides with different degrees of heterology. The efficiency of strand exchange is highly sensitive to the location, type, and distribution of mismatches. Mismatches near the 3' end of the initiating DNA strand have a small effect, whereas most mismatches near the 5' end impede strand exchange dramatically. The Hop2-Mnd1 protein complex stimulates Dmc1-catalyzed strand exchange on homologous DNA or containing a single mismatch. We observed that Dmc1 can reject divergent DNA sequences while bypassing a few mismatches in the DNA sequence. Our findings have important implications in understanding meiotic recombination. First, Dmc1 acts as an initial barrier for heterologous recombination, with the mismatch repair system providing a second level of proofreading, to ensure that ectopic sequences are not recombined. Second, Dmc1 stepping over infrequent mismatches is likely critical for allowing recombination between the polymorphic sequences of homologous chromosomes, thus contributing to gene conversion and genetic diversity. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Marine (Brander-Smith report) and non-marine spills

International Nuclear Information System (INIS)

Anon.

1992-01-01

Current activities related to Canada's Green Plan are reviewed in the area of research on, and response to, marine and non-marine spills. The Emergency Response section of Environment Canada's Conservation and Protection Service has had a 130% increase in funding and 50% increase in personnel resources. Two thirds of these resources are assigned to regional operations where spill incidents occur and the rest to research. The section's first priority is to improve its spill prevention program. A national standard for emergency planning for industry has been prepared and thousands of copies have been sold. A Canada-USA joint inland pollution contingency plan will be established and training programs on response to oil and hazardous chemical spills has been implemented. Resources applied to spill response have also increased 150%; a computerized communications network has been provided for spill response personnel, with the aim to develop a single national spill reporting system. In terms of policy initiatives, amendments are being made to the Canada Shipping Act that will require on-board pollution emergency plans for ships operating in Canadian waters. A liability and compensation regime for chemical spills is being considered, as well as reimposition of a levy on petroleum products that resulted in creation of a ship-source oil pollution fund. Radar-based traffic control systems for heavily congested marine areas, electronic charting, and increased inspection of ships are among the spill prevention initiatives in progress. Research is being conducted on mapping environmentally sensitive shorelines and in oil spill cleanup methods

Performance of Nb3Sn RRP strands and cables based on a 108/127 stack design

International Nuclear Information System (INIS)

Barzi, E.; Ambrosio, G.; Andreev, N.; Bossert, R.; Carcagno, R.; Feher, S.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; Nobrega, F.; Novitski, I.; Pishalnikov, Y.; Sylvester, C.; Tartaglia, M.; Turrioni, D.; Yamada, R.; Zlobin, A.V.; Field, M.; Hong, S.; Parrell, J.; Zhang, Y.

2006-01-01

The high performance Nb 3 Sn strand produced by Oxford Superconducting Technology (OST) with the Restack Rod Process (RRP) is presently considered as a baseline conductor for the Fermilab's accelerator magnet R and D program. To improve the strand stability in the current and field range expected in magnet models, the number of subelements in the strand was increased by a factor of two (from 54 to 108), which resulted in a smaller effective filament size. The performance of the 1.0 and 0.7 mm strands of this design was studied using virgin and deformed strand samples. 27-strand Rutherford cables made of 1 mm strand were also tested using a superconducting transformer, small racetrack and 1-m shell-type dipole coils. This paper presents the RRP strand and cable parameters, and reports the results of strand, cable and coil testing

NODC Standard Product: NOAA Marine environmental buoy database 1993 with Updates (19 disc set) (NCEI Accession 0095199)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This set of CD-ROMs holds marine meteorological, oceanographic, and wave spectra data collected by moored buoys and C-MAN (Coastal-Marine Automated Network) stations...

Strand-Specific Analysis of DNA Synthesis and Proteins Association with DNA Replication Forks in Budding Yeast.

Science.gov (United States)

Yu, Chuanhe; Gan, Haiyun; Zhang, Zhiguo

2018-01-01

DNA replication initiates at DNA replication origins after unwinding of double-strand DNA(dsDNA) by replicative helicase to generate single-stranded DNA (ssDNA) templates for the continuous synthesis of leading-strand and the discontinuous synthesis of lagging-strand. Therefore, methods capable of detecting strand-specific information will likely yield insight into the association of proteins at leading and lagging strand of DNA replication forks and the regulation of leading and lagging strand synthesis during DNA replication. The enrichment and Sequencing of Protein-Associated Nascent DNA (eSPAN), which measure the relative amounts of proteins at nascent leading and lagging strands of DNA replication forks, is a step-wise procedure involving the chromatin immunoprecipitation (ChIP) of a protein of interest followed by the enrichment of protein-associated nascent DNA through BrdU immunoprecipitation. The isolated ssDNA is then subjected to strand-specific sequencing. This method can detect whether a protein is enriched at leading or lagging strand of DNA replication forks. In addition to eSPAN, two other strand-specific methods, (ChIP-ssSeq), which detects potential protein-ssDNA binding and BrdU-IP-ssSeq, which can measure synthesis of both leading and lagging strand, were developed along the way. These methods can provide strand-specific and complementary information about the association of the target protein with DNA replication forks as well as synthesis of leading and lagging strands genome wide. Below, we describe the detailed eSPAN, ChIP-ssSeq, and BrdU-IP-ssSeq protocols.

A data delivery system for IMOS, the Australian Integrated Marine Observing System

Science.gov (United States)

Proctor, R.; Roberts, K.; Ward, B. J.

2010-09-01

The Integrated Marine Observing System (IMOS, www.imos.org.au), an AUD 150 m 7-year project (2007-2013), is a distributed set of equipment and data-information services which, among many applications, collectively contribute to meeting the needs of marine climate research in Australia. The observing system provides data in the open oceans around Australia out to a few thousand kilometres as well as the coastal oceans through 11 facilities which effectively observe and measure the 4-dimensional ocean variability, and the physical and biological response of coastal and shelf seas around Australia. Through a national science rationale IMOS is organized as five regional nodes (Western Australia - WAIMOS, South Australian - SAIMOS, Tasmania - TASIMOS, New SouthWales - NSWIMOS and Queensland - QIMOS) surrounded by an oceanic node (Blue Water and Climate). Operationally IMOS is organized as 11 facilities (Argo Australia, Ships of Opportunity, Southern Ocean Automated Time Series Observations, Australian National Facility for Ocean Gliders, Autonomous Underwater Vehicle Facility, Australian National Mooring Network, Australian Coastal Ocean Radar Network, Australian Acoustic Tagging and Monitoring System, Facility for Automated Intelligent Monitoring of Marine Systems, eMarine Information Infrastructure and Satellite Remote Sensing) delivering data. IMOS data is freely available to the public. The data, a combination of near real-time and delayed mode, are made available to researchers through the electronic Marine Information Infrastructure (eMII). eMII utilises the Australian Academic Research Network (AARNET) to support a distributed database on OPeNDAP/THREDDS servers hosted by regional computing centres. IMOS instruments are described through the OGC Specification SensorML and where-ever possible data is in CF compliant netCDF format. Metadata, conforming to standard ISO 19115, is automatically harvested from the netCDF files and the metadata records catalogued in the

Marine Research Infrastructure collaboration in the COOPLUS project framework - Promoting synergies for marine ecosystems studies

Science.gov (United States)

Beranzoli, L.; Best, M.; Embriaco, D.; Favali, P.; Juniper, K.; Lo Bue, N.; Lara-Lopez, A.; Materia, P.; Ó Conchubhair, D.; O'Rourke, E.; Proctor, R.; Weller, R. A.

2017-12-01

Understanding effects on marine ecosystems of multiple drivers at various scales; from regional such as climate and ocean circulation, to local, such as seafloor gas emissions and harmful underwater noise, requires long time-series of integrated and standardised datasets. Large-scale research infrastructures for ocean observation are able to provide such time-series for a variety of ocean process physical parameters (mass and energy exchanges among surface, water column and benthic boundary layer) that constitute important and necessary measures of environmental conditions and change/development over time. Information deduced from these data is essential for the study, modelling and prediction of marine ecosystems changes and can reveal and potentially confirm deterioration and threats. The COOPLUS European Commission project brings together research infrastructures with the aim of coordinating multilateral cooperation among RIs and identifying common priorities, actions, instruments, resources. COOPLUS will produce a Strategic Research and Innovation Agenda (SRIA) which will be a shared roadmap for mid to long-term collaboration. In particular, marine RIs collaborating in COOPLUS, namely the European Multidisciplinary Seafloor and water column Observatory: EMSO (Europe), the Ocean Observatories Initiative (OOI, USA), Ocean Networks Canada (ONC), and the Integrated Marine Observing System (IMOS, Australia), can represent a source of important data for researchers of marine ecosystems. The RIs can then, in turn, receive suggestions from researchers for implementing new measurements and stimulating cross-cutting collaborations and data integration and standardisation from their user community. This poster provides a description of EMSO, OOI, ONC and IMOS for the benefit of marine ecosystem studies and presents examples of where the analyses of time-series have revealed noteworthy environmental conditions, temporal trends and events.

Environmental implications of plastic debris in marine settings--entanglement, ingestion, smothering, hangers-on, hitch-hiking and alien invasions.

Science.gov (United States)

Gregory, Murray R

2009-07-27

Over the past five or six decades, contamination and pollution of the world's enclosed seas, coastal waters and the wider open oceans by plastics and other synthetic, non-biodegradable materials (generally known as 'marine debris') has been an ever-increasing phenomenon. The sources of these polluting materials are both land- and marine-based, their origins may be local or distant, and the environmental consequences are many and varied. The more widely recognized problems are typically associated with entanglement, ingestion, suffocation and general debilitation, and are often related to stranding events and public perception. Among the less frequently recognized and recorded problems are global hazards to shipping, fisheries and other maritime activities. Today, there are rapidly developing research interests in the biota attracted to freely floating (i.e. pelagic) marine debris, commonly known as 'hangers-on and hitch-hikers' as well as material sinking to the sea floor despite being buoyant. Dispersal of aggressive alien and invasive species by these mechanisms leads one to reflect on the possibilities that ensuing invasions could endanger sensitive, or at-risk coastal environments (both marine and terrestrial) far from their native habitats.

Environmental implications of plastic debris in marine settings—entanglement, ingestion, smothering, hangers-on, hitch-hiking and alien invasions

Science.gov (United States)

Gregory, Murray R.

2009-01-01

Over the past five or six decades, contamination and pollution of the world’s enclosed seas, coastal waters and the wider open oceans by plastics and other synthetic, non-biodegradable materials (generally known as ‘marine debris’) has been an ever-increasing phenomenon. The sources of these polluting materials are both land- and marine-based, their origins may be local or distant, and the environmental consequences are many and varied. The more widely recognized problems are typically associated with entanglement, ingestion, suffocation and general debilitation, and are often related to stranding events and public perception. Among the less frequently recognized and recorded problems are global hazards to shipping, fisheries and other maritime activities. Today, there are rapidly developing research interests in the biota attracted to freely floating (i.e. pelagic) marine debris, commonly known as ‘hangers-on and hitch-hikers’ as well as material sinking to the sea floor despite being buoyant. Dispersal of aggressive alien and invasive species by these mechanisms leads one to reflect on the possibilities that ensuing invasions could endanger sensitive, or at-risk coastal environments (both marine and terrestrial) far from their native habitats. PMID:19528053

Stranding of two sperm whales (Physeter macrocephalus) in the "North Sea trap" at Henne Strand, Denmark

DEFF Research Database (Denmark)

Hansen, Mette Sif; Alstrup, Aage K. O.; Hansen, Jørgen H.

2016-01-01

In February 2014 two male sperm whales (Physeter macrocephalus) stranded at Henne Strand, Denmark. One whale (MCE 1644) was found dead, while the other (MCE 1645) was still alive, but drowned during the high tide. To increase our knowledge of sperm whales, conduct forage investigations, post......-mortem and diagnostic examinations were carried out. The decay of the carcasses progressed quickly. The whales had large (MCE 1644) or moderate (MCE 1645) numbers of squid beaks (Gonatus fabricii) in the stomachventricles, but no evidence of recentfresh feeding. Both whales had acute dermatitis probably due to trauma...... severe localized or systemic infections. The finding of large volumes of bloody pleural fluid with large quantities of C. septicum suggests that MCE 1644 died of infection. However, reservations must be taken due to the pronounced decay of the carcass. Sperm whales have strong social bonds where...

Coronavirus minus-strand RNA synthesis and effect of cycloheximide on coronavirus RNA synthesis

International Nuclear Information System (INIS)

Sawicki, S.G.; Sawicki, D.L.

1986-01-01

The temporal sequence of coronavirus plus-strand and minus-strand RNA synthesis was determined in 17CL1 cells infected with the A59 strain of mouse hepatitis virus (MHV). MHV-induced fusion was prevented by keeping the pH of the medium below pH 6.8. This had no effect on the MHV replication cycle, but gave 5- to 10-fold-greater titers of infectious virus and delayed the detachment of cells from the monolayer which permitted viral RNA synthesis to be studied conveniently until at least 10 h postinfection. Seven species of poly(A)-containing viral RNAs were synthesized at early and late times infection, in nonequal but constant ratios. MHV minus-strand RNA synthesis was first detected at about 3 h after infection and was found exclusively in the viral replicative intermediates and was not detected in 60S single-stranded form in infected cells. Early in the replication cycle, from 45 to 65% of the [ 3 H]uridine pulse-labeled RF core of purified MHV replicative intermediates was in minus-strand RNA. The rate of minus-strand synthesis peaked at 5 to 6 h postinfection and then declined to about 20% of the maximum rate. The addition of cycloheximide before 3 h postinfection prevented viral RNA synthesis, whereas the addition of cycloheximide after viral RNA synthesis had begun resulted in the inhibition of viral RNA synthesis. The synthesis of both genome and subgenomic mRNAs and of viral minus strands required continued protein synthesis, and minis-strand RNA synthesis was three- to fourfold more sensitive to inhibition of cycloheximide than was plus-strand synthesis

Wireless Local Area Network (WLAN) Vulnerability Assessment and Security

National Research Council Canada - National Science Library

Kessel, Adam; Goodwin, Shane

2005-01-01

The proliferation of wireless computer equipment and Local Area Networks (LANs) create an increasingly common and growing threat to Marine Corps Network infrastructure and communication security (COMSEC...

Strand critical current degradation in $Nb_{3}$ Sn Rutherford cables

CERN Document Server

Barzi, E; Higley, H C; Scanlan, R M; Yamada, R; Zlobin, A V

2001-01-01

Fermilab is developing 11 Tesla superconducting accelerator magnets based on Nb/sub 3/Sn superconductor. Multifilamentary Nb/sub 3/Sn strands produced using the modified jelly roll, internal tin, and powder-in-tube technologies were used for the development and test of the prototype cable. To optimize the cable geometry with respect to the critical current, short samples of Rutherford cable with packing factors in the 85 to 95% range were fabricated and studied. In this paper, the results of measurements of critical current, n-value and RRR made on the round virgin strands and on the strands extracted from the cable samples are presented. (5 refs).

Performance of Nb3Sn RRP strands and cables based on a 108/127 stack design

Energy Technology Data Exchange (ETDEWEB)

Barzi, E.; Ambrosio, G.; Andreev, N.; Bossert, R.; Carcagno, R.; Feher, S.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; Nobrega, F.; Novitski, I.; /Fermilab /Oxford Supercond. Tech., Carteret

2006-08-01

The high performance Nb{sub 3}Sn strand produced by Oxford Superconducting Technology (OST) with the Restack Rod Process (RRP) is presently considered as a baseline conductor for the Fermilab's accelerator magnet R&D program. To improve the strand stability in the current and field range expected in magnet models, the number of subelements in the strand was increased by a factor of two (from 54 to 108), which resulted in a smaller effective filament size. The performance of the 1.0 and 0.7 mm strands of this design was studied using virgin and deformed strand samples. 27-strand Rutherford cables made of 1 mm strand were also tested using a superconducting transformer, small racetrack and 1-m shell-type dipole coils. This paper presents the RRP strand and cable parameters, and reports the results of strand, cable and coil testing.

Induction and repair of double- and single-strand DNA breaks in bacteriophage lambda superinfecting Escherichia coli

International Nuclear Information System (INIS)

Boye, E.; Krisch, R.E.

1980-01-01

Induction and repair of double-and single-strand DNA breaks have been measured after decays of 125 I and 3 H incorporated into the DNA and after external irradiation with 4 MeV electrons. For the decay experiments, cells of wild type Escherichia coli K-12 were superinfected with bacteriophage lambda DNA labelled with 5'-( 125 I)iodo-2'-deoxyuridine or with (methyl- 3 H)thymidine and frozen in liquid nitrogen. Aliquots were thawed at intervals and lysed at neutral pH, and the phage DNA was assayed for double- and single-strand breakage by neutral sucrose gradient centrifugation. The gradients used allowed measurements of both kinds of breaks in the same gradient. Decays of 125 I induced 0.39 single-strand breaks per double-strand break. No repair of either break type could be detected. Each 3 H disintegration caused 0.20 single-strand breaks and very few double-strand breaks. The single-strand breaks were rapidly rejoined after the cells were thawed. For irradiation with 4 MeV electrons, cells of wild type E. coli K-12 were superinfected with phage lambda and suspended in growth medium. Irradiation induced 42 single-strand breaks per double-strand break. The rates of break induction were 6.75 x 10 -14 (double-strand breaks) and 2.82 x 10 -12 (single-strand breaks) per rad and per dalton. The single-strand breaks were rapidly repaired upon incubation whereas the double-strand breaks seemed to remain unrepaired. It is concluded that double-strand breaks in superinfecting bacteriophage lambda DNA are repaired to a very small extent, if at all. (Author)

European Research in Marine Structures

DEFF Research Database (Denmark)

Soares, C.Guedes; Jensen, Jørgen Juncher; Incecik, A.

2012-01-01

An overview is presented of the results obtained in Europe by a network with a large number of research groups in the field of Marine Structures during a period of 6 years. The European Union has funded a project aimed at improving the collaboration among European research groups specialized...... in marine structures, which has led, among other results to a number of benchmark studies organized in 6 main topical areas, namely, Methods and Tools for Loads and Load Effects, Methods and Tools for Strength Assessment, Experimental Analysis of Structures, Materials and Fabrication of Structures, Methods...... and Tools for Structural Design and Optimization and Structural Reliability, Safety and Environmental Protection. This paper presents an overview of various studies performed, which helps identifying the level of consistency and robustness of different numeric tools used in this field....

Mammalian DNA single-strand break repair: an X-ra(y)ted affair.

Science.gov (United States)

Caldecott, K W

2001-05-01

The genetic stability of living cells is continuously threatened by the presence of endogenous reactive oxygen species and other genotoxic molecules. Of particular threat are the thousands of DNA single-strand breaks that arise in each cell, each day, both directly from disintegration of damaged sugars and indirectly from the excision repair of damaged bases. If un-repaired, single-strand breaks can be converted into double-strand breaks during DNA replication, potentially resulting in chromosomal rearrangement and genetic deletion. Consequently, cells have adopted multiple pathways to ensure the rapid and efficient removal of single-strand breaks. A general feature of these pathways appears to be the extensive employment of protein-protein interactions to stimulate both the individual component steps and the overall repair reaction. Our current understanding of DNA single-strand break repair is discussed, and testable models for the architectural coordination of this important process are presented. Copyright 2001 John Wiley & Sons, Inc.

The Effect of Basepair Mismatch on DNA Strand Displacement

OpenAIRE

Broadwater, D.?W.?Bo; Kim, Harold?D.

2016-01-01

DNA strand displacement is a key reaction in DNA homologous recombination and DNA mismatch repair and is also heavily utilized in DNA-based computation and locomotion. Despite its ubiquity in science and engineering, sequence-dependent effects of displacement kinetics have not been extensively characterized. Here, we measured toehold-mediated strand displacement kinetics using single-molecule fluorescence in the presence of a single base pair mismatch. The apparent displacement rate varied si...

Repair and gamma radiation-induced single- and double-strand breaks in DNA of Escherichia coli

International Nuclear Information System (INIS)

Petrov, S.I.

1981-01-01

Studies in the kinetics of repair of γ-radiation-induced single- and double-strand breaks in DNA of E. coli cells showed that double-strand DNA breaks are rejoined by the following two ways. The first way is conditioned by repair of single-strand breaks and represents the repair of ''oblique'' double-strand breaks in DNA, whereas the second way is conditioned by functioning of the recombination mechanisms and, to all appearance, represents the repair of ''direct'' double-strand breaks in DNA

Interstrand cross-links arising from strand breaks at true abasic sites in duplex DNA

Science.gov (United States)

Yang, Zhiyu; Price, Nathan E.; Johnson, Kevin M.

2017-01-01

Abstract Interstrand cross-links are exceptionally bioactive DNA lesions. Endogenous generation of interstrand cross-links in genomic DNA may contribute to aging, neurodegeneration, and cancer. Abasic (Ap) sites are common lesions in genomic DNA that readily undergo spontaneous and amine-catalyzed strand cleavage reactions that generate a 2,3-didehydro-2,3-dideoxyribose sugar remnant (3’ddR5p) at the 3’-terminus of the strand break. Interestingly, this strand scission process leaves an electrophilic α,β-unsaturated aldehyde residue embedded within the resulting nicked duplex. Here we present evidence that 3’ddR5p derivatives generated by spermine-catalyzed strand cleavage at Ap sites in duplex DNA can react with adenine residues on the opposing strand to generate a complex lesion consisting of an interstrand cross-link adjacent to a strand break. The cross-link blocks DNA replication by ϕ29 DNA polymerase, a highly processive polymerase enzyme that couples synthesis with strand displacement. This suggests that 3’ddR5p-derived cross-links have the potential to block critical cellular DNA transactions that require strand separation. LC-MS/MS methods developed herein provide powerful tools for studying the occurrence and properties of these cross-links in biochemical and biological systems. PMID:28531327

POSTMORTEM FINDINGS IN CETACEANS FOUND STRANDED IN THE PELAGOS SANCTUARY, ITALY, 2007-14.

Science.gov (United States)

Giorda, Federica; Ballardini, Marco; Di Guardo, Giovanni; Pintore, Maria Domenica; Grattarola, Carla; Iulini, Barbara; Mignone, Walter; Goria, Maria; Serracca, Laura; Varello, Katia; Dondo, Alessandro; Acutis, Pier Luigi; Garibaldi, Fulvio; Scaglione, Frine Eleonora; Gustinelli, Andrea; Mazzariol, Sandro; Di Francesco, Cristina Esmeralda; Tittarelli, Cristiana; Casalone, Cristina; Pautasso, Alessandra

2017-10-01

Between 2007 and 2014, 83 cetaceans were found stranded along the Ligurian coast of Italy, in the Pelagos Sanctuary, the largest marine protected area in the Mediterranean basin. Forty-nine (59%) were submitted to complete or partial necropsy, depending on the conservation status of the carcass. Based on gross and histological pathology and ancillary testing, the cause of death was determined and categorized as anthropogenic or natural (i.e., nonanthropogenic) in origin for 33 animals (67%) and of undetermined origin in the remaining 16 (33%). Natural causes of death, accompanied by either poor or good nutritional status, were attributed to 29 animals (59%), whereas four (8%) were diagnosed with an anthropogenic cause of death, consisting of interaction with fishing activities. Infectious and noninfectious disease was the most common cause of death, involving 29 cetaceans (59%). These data are valuable for understanding health and mortality trends in cetacean populations and can provide information for establishing policies for cetacean conservation and management in such an important protected area of the Mediterranean basin.

Magnetization, Low Field Instability and Quench of RHQT Nb(3)Al Strands

Energy Technology Data Exchange (ETDEWEB)

Yamada, R.; Wake, M.; Kikuchi, A.; Velev, V.; /Fermilab

2009-01-01

Since 2005, we made and tested three RHQT Nb{sub 3}Al strands, one with Nb matrix and two with Ta matrix, which are fully stabilized with Cu electroplating. We observed anomalously large magnetization curves extending beyond 1 to 1.5 Tesla with the F1 Nb matrix strand at 4.2 K, when we measured its magnetization with a balanced coil magnetometer. This problem was eliminated with the Ta matrix strands operating at 4.2 K. But with these strands a similar but smaller anomalous magnetization was observed at 1.9 K. We studied these phenomena with FEM. With the F1 Nb matrix strand, it is explained that at low external field, inter-filamentary coupling currents in the outer layers of sub-elements create a shielding effect. It reduces the inside field, keeps the inside Nb matrix superconductive, and stands against a higher outside field beyond the Hc of Nb. At an even higher external field, the superconductivity of the whole Nb matrix collapses and releases a large amount of energy, which may cause a big quench. Depending on the size of the energy in the strand or the cable, a magnet could quench, causing the low field instability. Some attempt to analyze the anomaly with FEM is presented.

Development of Nb3Sn strands for ITER in Japan

International Nuclear Information System (INIS)

Isono, T.; Nunoya, Y.; Matsui, K.; Nabara, Y.; Koizumi, N.; Takahashi, Y.; Okuno, K.

2007-01-01

Nb 3 Sn strands for ITER Toroidal Field (TF) coils and Central Solenoids (CS) are required to have both high current density (Jc) and low hysteresis loss. The required Jc at 12 T, 4.2 K and no external strain is lager than 700 A/mm 2 for bronze processed strand and lager than 800 A/mm 2 for internal tin processed one at 12 T, 4.2 K and no external strain. Upper limit of hysteresis loss is 1,000 mJ/cm 3 at 4.2 K and a cycle of ±3 T. Outer diameter is 0.82 mm and 0.83 mm for TF coils and CS, respectively. Area ratio of copper to non copper is one and outer surface is Cr plated. Japan will procure 25% of Nb 3 Sn for ITER TF coils and 100% for ITER CS. There are four Nb 3 Sn strand suppliers in Japan; three of them use bronze process and the other uses internal tin process. For bronze processed strand, increase Jc was achieved by using bronze with high tin content of 15 to 16%. To keep productivity while using the harder bronze with high tin content, Nb is used for barrier in place of Ta. The material is expected to have better adhesion to other materials such as bronze and copper. For internal tin process, size of modules, each of which has a tin rod and a lot of Nb filaments embedded in a copper cylinder, is reduced, while total amount of tin increase in order to satisfy both required high Jc and low hysteresis loss. Each supplier fabricated a strand of more than 0.1 ton for TF coils and succeeded to develop a strand satisfying the ITER requirements of Jc and hysteresis loss. (authors)

Influence of DNA conformation on radiation-induced single-strand breaks

International Nuclear Information System (INIS)

Barone, F.; Belli, M.; Mazzei, F.

1994-01-01

We performed experiments on two DNA fragments of about 300 bp having different conformation to test whether radiation-induced single-strand breakage is dependent on DNA conformation. Breakage analysis was carried out by denaturing polyacrylamide gel electrophoresis, which allows determination of the broken site at single nucleotide resolution. We found uniform cutting patterns in B-form regions. On the contrary, X- or γ-irradiation of curved fragments of kinetoplast DNA showed that the distribution of single-strand breaks was not uniform along the fragment, as the cleavage pattern was modulated in phase with the runs of A-T pairs. This modulation likely reflected the reduced accessibility of the sites which on hydroxyl-radical attack give rise to strand breaks. The cleavage pattern was phased with the runs of A-T pairs. Moreover, the overall yield of strand breaks was considerably lower in curved DNA fragments than in those with extended straight regions. The conformation effect found here indicates that the cleavage pattern reflects the fine structural features of DNA. (orig./MG)

Investigations of radiation-induced strand breaks of poly(U) in aqueous solutions

International Nuclear Information System (INIS)

Lemaire, D.G.E.

1984-01-01

DNA strand breaks induced by γ irradiation were studied in polyuridylic acid (Poly(U)), a single-strand model substance with a single base. Poly(U) in diluted, aqueous solution was irradiated in a Co-γ source, and the 100 eV yields of strand breaks (Cr values) were determined on the basis of the loss of molecular weight. The molecular weight was determined by small-angle laser light scattering. (orig./PW) [de

Electron attachment to DNA single strands: gas phase and aqueous solution.

Science.gov (United States)

Gu, Jiande; Xie, Yaoming; Schaefer, Henry F

2007-01-01

The 2'-deoxyguanosine-3',5'-diphosphate, 2'-deoxyadenosine-3',5'-diphosphate, 2'-deoxycytidine-3',5'-diphosphate and 2'-deoxythymidine-3',5'-diphosphate systems are the smallest units of a DNA single strand. Exploring these comprehensive subunits with reliable density functional methods enables one to approach reasonable predictions of the properties of DNA single strands. With these models, DNA single strands are found to have a strong tendency to capture low-energy electrons. The vertical attachment energies (VEAs) predicted for 3',5'-dTDP (0.17 eV) and 3',5'-dGDP (0.14 eV) indicate that both the thymine-rich and the guanine-rich DNA single strands have the ability to capture electrons. The adiabatic electron affinities (AEAs) of the nucleotides considered here range from 0.22 to 0.52 eV and follow the order 3',5'-dTDP > 3',5'-dCDP > 3',5'-dGDP > 3',5'-dADP. A substantial increase in the AEA is observed compared to that of the corresponding nucleic acid bases and the corresponding nucleosides. Furthermore, aqueous solution simulations dramatically increase the electron attracting properties of the DNA single strands. The present investigation illustrates that in the gas phase, the excess electron is situated both on the nucleobase and on the phosphate moiety for DNA single strands. However, the distribution of the extra negative charge is uneven. The attached electron favors the base moiety for the pyrimidine, while it prefers the 3'-phosphate subunit for the purine DNA single strands. In contrast, the attached electron is tightly bound to the base fragment for the cytidine, thymidine and adenosine nucleotides, while it almost exclusively resides in the vicinity of the 3'-phosphate group for the guanosine nucleotides due to the solvent effects. The comparatively low vertical detachment energies (VDEs) predicted for 3',5'-dADP(-) (0.26 eV) and 3',5'-dGDP(-) (0.32 eV) indicate that electron detachment might compete with reactions having high activation barriers

Controlled Folding, Motional, and Constitutional Dynamic Processes of Polyheterocyclic Molecular Strands.

Science.gov (United States)

Barboiu, Mihail; Stadler, Adrian-Mihail; Lehn, Jean-Marie

2016-03-18

General design principles have been developed for the control of the structural features of polyheterocyclic strands and their effector-modulated shape changes. Induced defined molecular motions permit designed enforcement of helical as well as linear molecular shapes. The ability of such molecular strands to bind metal cations allows the generation of coiling/uncoiling processes between helically folded and extended linear states. Large molecular motions are produced on coordination of metal ions, which may be made reversible by competition with an ancillary complexing agent and fueled by sequential acid/base neutralization energy. The introduction of hydrazone units into the strands confers upon them constitutional dynamics, whereby interconversion between different strand compositions is achieved through component exchange. These features have relevance for nanomechanical devices. We present a morphological and functional analysis of such systems developed in our laboratories. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Enhancement of orimulsion biodegradation through the addition of natural marine carbon substrates

Energy Technology Data Exchange (ETDEWEB)

Proctor, L.M.; Toy, E.; Lapham, L.; Cherrier, J.; Chanton, J.P. [Florida State University, Tallahassee, FL (USA). Dept. of Oceanography

2001-04-01

Orimulsion is a bitumen-based heavy fuel that is a less expensive alternative to traditional fuel oils. However, because its density is intermediate between that of freshwater and seawater, in the event of a spill, the fuel could strand in the sediments. Previous work indicated that only 0.6 - 2.7% of the bitumen would degrade in long incubations of marine sediments. Various natural carbon substrates were added to stimulate the degradation of bitumen by native populations of benthic bacteria. The concentration and carbon isotopic signature of the respired carbon dioxide was measured to partition the substrates that supported bacterial respiration. It was found that the addition of seagrass and pinfish stimulated the degradation of bitumen by as much as 2 to 9-fold relative to incubations without these substrates. Biodegradation of bitumen may be enhanced by the addition of natural marine carbon substrates and may be a useful approach for bioremediation. Preadaption of the bacteria to bitumen did not significantly enhance their ability to degrade it. 13 refs., 5 figs., 2 tab.

Enzyme-free colorimetric detection systems based on the DNA strand displacement competition reaction

Science.gov (United States)

Zhang, Z.; Birkedal, V.; Gothelf, K. V.

2016-05-01

The strand displacement competition assay is based on the dynamic equilibrium of the competitive hybridization of two oligonucleotides (A and B) to a third oligonucleotide (S). In the presence of an analyte that binds to a specific affinity-moiety conjugated to strand B, the equilibrium shifts, which can be detected by a shift in the fluorescence resonance energy transfer signal between dyes attached to the DNA strands. In the present study we have integrated an ATP aptamer in the strand B and demonstrated the optical detection of ATP. Furthermore we explore a new readout method using a split G-quadruplex DNAzyme for colorimetric readout of the detection of streptavidin by the naked eye. Finally, we integrate the whole G-quadruplex DNAzyme system in a single DNA strand and show that it is applicable to colorimetric detection.

Enzyme-free colorimetric detection systems based on the DNA strand displacement competition reaction

DEFF Research Database (Denmark)

Zhang, Zhao; Birkedal, Victoria; Gothelf, Kurt Vesterager

2016-01-01

The strand displacement competition assay is based on the dynamic equilibrium of the competitive hybridization of two oligonucleotides (A and B) to a third oligonucleotide (S). In the presence of an analyte that binds to a specific affinity-moiety conjugated to strand B, the equilibrium shifts, w...... G-quadruplex DNAzyme for colorimetric readout of the detection of streptavidin by the naked eye. Finally, we integrate the whole G-quadruplex DNAzyme system in a single DNA strand and show that it is applicable to colorimetric detection......., which can be detected by a shift in the fluorescence resonance energy transfer signal between dyes attached to the DNA strands. In the present study we have integrated an ATP aptamer in the strand B and demonstrated the optical detection of ATP. Furthermore we explore a new readout method using a split...

The REDCAM, institutional Cooperation for the Surveillance of the Quality of the Marine and Coastal waters in Colombia

International Nuclear Information System (INIS)

Ana Maria Velez G; Marin Z, Bienvenido; Garay T, Jesus A

2003-01-01

The Colombian Marine Environment Monitoring Network (REDCAM) initiated in 2001, with the purpose of grouping the institutions and the efforts necessary to evaluate the chemical and sanitary quality of the marine and estuarine waters of Colombia; it is composed of 16 nodes and main server located at INVEMAR (Santa Marta); each node counts with hardware and software for a Input and retrieval tables and cartographic information a about the quality o marine and coastal waters of Colombia. It was established a network of field stations that covers most of the Colombian coasts. In each one, since 2001, twice a year, it has been registering the values of the main physicochemical and bacteriological variables that characterize the quality of the marine and estuarine waters. Based on this information, the following zones have been identified as critical for its marine and coastal pollution: Santa Marta, Cartagena, Barranquilla, Morrosquillo, Uraba and San Andres, in the Caribbean coast and Buenaventura, Guapi and La Tola in Pacific coast

Interstrand cross-links arising from strand breaks at true abasic sites in duplex DNA.

Science.gov (United States)

Yang, Zhiyu; Price, Nathan E; Johnson, Kevin M; Wang, Yinsheng; Gates, Kent S

2017-06-20

Interstrand cross-links are exceptionally bioactive DNA lesions. Endogenous generation of interstrand cross-links in genomic DNA may contribute to aging, neurodegeneration, and cancer. Abasic (Ap) sites are common lesions in genomic DNA that readily undergo spontaneous and amine-catalyzed strand cleavage reactions that generate a 2,3-didehydro-2,3-dideoxyribose sugar remnant (3'ddR5p) at the 3'-terminus of the strand break. Interestingly, this strand scission process leaves an electrophilic α,β-unsaturated aldehyde residue embedded within the resulting nicked duplex. Here we present evidence that 3'ddR5p derivatives generated by spermine-catalyzed strand cleavage at Ap sites in duplex DNA can react with adenine residues on the opposing strand to generate a complex lesion consisting of an interstrand cross-link adjacent to a strand break. The cross-link blocks DNA replication by ϕ29 DNA polymerase, a highly processive polymerase enzyme that couples synthesis with strand displacement. This suggests that 3'ddR5p-derived cross-links have the potential to block critical cellular DNA transactions that require strand separation. LC-MS/MS methods developed herein provide powerful tools for studying the occurrence and properties of these cross-links in biochemical and biological systems. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Critical current scaling and the pivot-point in Nb3Sn strands

International Nuclear Information System (INIS)

Tsui, Y; Hampshire, D P

2012-01-01

Detailed measurements are provided of the engineering critical current density (J c ) and the index of transition (n-value) of two different types of advanced ITER Nb 3 Sn superconducting strand for fusion applications. The samples consist of one internal-tin strand (OST) and two bronze-route strands (BEAS I and BEAS II—reacted using different heat treatments). Tests on different sections of these wires show that prior to applying strain, J c is homogeneous to better than 2% along the length of each strand. J c data have been characterized as a function of magnetic field (B ≤ 14.5 T), temperature (4.2 K ≤ T ≤ 12 K) and applied axial strain ( − 1% ≤ ε A ≤ 0.8%). Strain-cycling tests demonstrate that the variable strain J c data are reversible to better than 2% when the applied axial strain is in the range of − 1% ≤ ε A ≤ 0.5%. The wires are damaged when the intrinsic strain (ε I ) is ε I ≥ 0.55% and ε I ≥ 0.23% for the OST and BEAS strands, respectively. The strain dependences of the normalized J c for each type of strand are similar to those of prototype strands of similar design measured in 2005 and 2008 to about 2% which makes them candidate strands for a round-robin interlaboratory comparison. The J c data are described by Durham, ITER and Josephson-junction parameterizations to an accuracy of about 4%. For all of these scaling laws, the percentage difference between the data and the parameterization is larger when J c is small, caused by high B, T or |ε I |. The n-values can be described by a modified power law of the form n=1+rI c s , where r and s are approximately constant and I c is the critical current. It has long been known that pivot-points (or cross-overs) in J c occur at high magnetic field and temperature. Changing the magnetic field or temperature from one side of the pivot-point to the other changes the highest J c sample to the lowest J c sample and vice versa. The pivot-point follows the B–T phase boundary

Bridging Organizations Drive Effective Governance Outcomes for Conservation of Indonesia's Marine Systems.

Science.gov (United States)

Berdej, Samantha M; Armitage, Derek R

2016-01-01

This study empirically investigates the influence of bridging organizations on governance outcomes for marine conservation in Indonesia. Conservation challenges require ways of governing that are collaborative and adaptive across boundaries, and where conservation actions are better coordinated, information flows improved, and knowledge better integrated and mobilized. We combine quantitative social network analysis and qualitative data to analyze bridging organizations and their networks, and to understand their contributions and constraints in two case studies in Bali, Indonesia. The analysis shows 1) bridging organizations help to navigate the 'messiness' inherent in conservation settings by compensating for sparse linkages, 2) the particular structure and function of bridging organizations influence governing processes (i.e., collaboration, knowledge sharing) and subsequent conservation outcomes, 3) 'bridging' is accomplished using different strategies and platforms for collaboration and social learning, and 4) bridging organizations enhance flexibility to adjust to changing marine conservation contexts and needs. Understanding the organizations that occupy bridging positions, and how they utilize their positionality in a governance network is emerging as an important determinant of successful conservation outcomes. Our findings contribute to a relatively new body of literature on bridging organizations in marine conservation contexts, and add needed empirical investigation into their value to governance and conservation in Coral Triangle nations and beyond.

Establishing an agenda for social studies research in marine renewable energy

DEFF Research Database (Denmark)

Watts, Laura; Kerr, Sandy

2014-01-01

To date, academic research relating to Marine Renewable Energy (MRE) has largely focused on resource assessment, technical viability and environmental impact. Experiences from onshore renewable energy tell us that social acceptability is equally critical to project success. However, the specific...... nature of the marine environment, patterns of resource distribution and governance means experiences from onshore may not be directly applicable to MRE and the marine environment. This paper sets out an agenda for social studies research linked to MRE, identifying key topics for future research: (i...... research network of social scientists with interests in marine renewable energy. Importantly, this research agenda has been informed by the experiences of developers, regulators and community groups in Orkney. The Orkney archipelago, off the north coast of Scotland, is home to the most intense cluster...

DNA Strand Breaks in Mitotic Germ Cells of Caenorhabditis elegans Evaluated by Comet Assay

Science.gov (United States)

Park, Sojin; Choi, Seoyun; Ahn, Byungchan

2016-01-01

DNA damage responses are important for the maintenance of genome stability and the survival of organisms. Such responses are activated in the presence of DNA damage and lead to cell cycle arrest, apoptosis, and DNA repair. In Caenorhabditis elegans, double-strand breaks induced by DNA damaging agents have been detected indirectly by antibodies against DSB recognizing proteins. In this study we used a comet assay to detect DNA strand breaks and to measure the elimination of DNA strand breaks in mitotic germline nuclei of C. elegans. We found that C. elegans brc-1 mutants were more sensitive to ionizing radiation and camptothecin than the N2 wild-type strain and repaired DNA strand breaks less efficiently than N2. This study is the first demonstration of direct measurement of DNA strand breaks in mitotic germline nuclei of C. elegans. This newly developed assay can be applied to detect DNA strand breaks in different C. elegans mutants that are sensitive to DNA damaging agents. PMID:26903030

Breaking DNA strands by extreme-ultraviolet laser pulses in vacuum

Czech Academy of Sciences Publication Activity Database

Nováková, Eva; Vyšín, Luděk; Burian, Tomáš; Juha, Libor; Davídková, Marie; Múčka, V.; Čuba, V.; Grisham, M. E.; Heinbuch, S.; Rocca, J.J.

2015-01-01

Roč. 91, č. 4 (2015), "042718-1"-"042718-8" ISSN 1539-3755 R&D Projects: GA ČR(CZ) GBP108/12/G108; GA ČR GA13-28721S Institutional support: RVO:68378271 ; RVO:61389005 Keywords : XUV * DNA damages * single- strand breaks (SSBs) * double- strand breaks (DSBs) Subject RIV: BO - Biophysics Impact factor: 2.288, year: 2014

Design and Characterization of DNA Strand-Displacement Circuits in Serum-Supplemented Cell Medium.

Science.gov (United States)

Fern, Joshua; Schulman, Rebecca

2017-09-15

The functional stability and lifetimes of synthetic molecular circuits in biological environments are important for long-term, stable sensors or controllers of cell or tissue behavior. DNA-based molecular circuits, in particular DNA strand-displacement circuits, provide simple and effective biocompatible control mechanisms and sensors, but are vulnerable to digestion by nucleases present in living tissues and serum-supplemented cell culture. The stability of double-stranded and single-stranded DNA circuit components in serum-supplemented cell medium and the corresponding effect of nuclease-mediated degradation on circuit performance were characterized to determine the major routes of degradation and DNA strand-displacement circuit failure. Simple circuit design choices, such as the use of 5' toeholds within the DNA complexes used as reactants in the strand-displacement reactions and the termination of single-stranded components with DNA hairpin domains at the 3' termini, significantly increase the functional lifetime of the circuit components in the presence of nucleases. Simulations of multireaction circuits, guided by the experimentally measured operation of single-reaction circuits, enable predictive realization of multilayer and competitive-reaction circuit behavior. Together, these results provide a basic route to increased DNA circuit stability in cell culture environments.

Radioactivity of marine environment: pr occupations of the Romanian Institute of Marine Research at Constanta (1977-1995)

International Nuclear Information System (INIS)

Bologa, Al.A.; Patrascu, V.

1996-01-01

A nuclear laboratory installed in the frame of Romanian Institute of Marine Research has been initially charged with the study of primary plankton productivity as a basic element of bio-productivity using the C-14 method. The results contributed with significant data to complete the ecological picture of the marine environment regarding particularly the nutrient basis of living resources. The laboratory developed its activities by a systematic space-time monitoring of the marine radioactivity making use of a large network of measuring stations extended from Danube mouths through the southern limit of Romanian seashore and occasionally offshore up to 90 miles. Currently, global beta measurements, radiochemical determinations (for Sr-90 for instance) and high resolution gamma spectroscopic measurements (especially on K-40, Cs-134, and Cs-137) are carried out. At the end of 199 a tritium determination chain has been installed to monitor continuously the environment from around Cernavoda NPP across the Dobrogea up to the sea shore. These measurements and studies were made under technical co-operation contracts with IAEA and other national or international organisations while the results were incorporated in two important documents: 'Global Inventory of Radioactivity of Mediterranean Sea (CIESEM/GIRMED)' and 'A Global Data Base of Marine Radioactivity (IAEA/GLOMARD)'

Identification of Novel Cetacean Poxviruses in Cetaceans Stranded in South West England.

Directory of Open Access Journals (Sweden)

James Barnett

Full Text Available Poxvirus infections in marine mammals have been mainly reported through their clinical lesions and electron microscopy (EM. Poxvirus particles in association with such lesions have been demonstrated by EM and were previously classified as two new viruses, cetacean poxvirus 1 (CePV-1 and cetacean poxvirus 2 (CePV-2. In this study, epidermal pox lesions in cetaceans stranded in South West England (Cornwall between 2008 and 2012 were investigated by electron microscopy and molecular analysis. PCR and sequencing of a highly conserved region within the viral DNA polymerase gene ruled out both parapox- and orthopoxviruses. Moreover, phylogenetic analysis of the PCR product clustered the sequences with those previously described as cetacean poxviruses. However, taking the close genetic distance of this gene fragment across the family of poxviridae into account, it is reasonable to postulate further, novel cetacean poxvirus species. The nucleotide similarity within each cluster (tentative species detected ranged from 98.6% to 100%, whilst the similarity between the clusters was no more than 95%. The detection of several species of poxvirus in different cetacean species confirms the likelihood of a heterogeneous cetacean poxvirus genus, comparable to the heterogeneity observed in other poxvirus genera.

Animal Telemetry Network (ATN)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — These data (updated daily) are from the Animal Telemetry Network (ATN) program. Begun as one of the field projects in the international Census of Marine Life, the...

Necropsy report of a fin whale (Balaenoptera physalus) stranded in Denmark in 2010

DEFF Research Database (Denmark)

Alstrup, Aage K. O.; Hedayat, Abdi; Jensen, Trine Hammer

2013-01-01

There is little detailed information on stranded fin whales (Balaenoptera physalus) in the scientific literature (Notarbartolo di Sciara et al., 2003). In Denmark, at least eight fin whales stranded between the years 1603 and 1958 (Kinze, 1995). On 16 June 2010, a live subadult or adult male fin...... whale stranded in the Bay of Vejle (55º 69' N, 9º 58' E), Denmark. Despite several attempts, it was not possible to rescue the fin whale, which was only partially exposed by the water. The fin whale succumbed after 5 d stranded in shallow water. The dead fin whale was transported to a nearby pier...

Hybrid Method Simulation of Slender Marine Structures

DEFF Research Database (Denmark)

Christiansen, Niels Hørbye

This present thesis consists of an extended summary and five appended papers concerning various aspects of the implementation of a hybrid method which combines classical simulation methods and artificial neural networks. The thesis covers three main topics. Common for all these topics...... only recognize patterns similar to those comprised in the data used to train the network. Fatigue life evaluation of marine structures often considers simulations of more than a hundred different sea states. Hence, in order for this method to be useful, the training data must be arranged so...... that a single neural network can cover all relevant sea states. The applicability and performance of the present hybrid method is demonstrated on a numerical model of a mooring line attached to a floating offshore platform. The second part of the thesis demonstrates how sequential neural networks can be used...

Protected DNA strand displacement for enhanced single nucleotide discrimination in double-stranded DNA

OpenAIRE

Khodakov, Dmitriy A.; Khodakova, Anastasia S.; Huang, David M.; Linacre, Adrian; Ellis, Amanda V.

2015-01-01

Single nucleotide polymorphisms (SNPs) are a prime source of genetic diversity. Discriminating between different SNPs provides an enormous leap towards the better understanding of the uniqueness of biological systems. Here we report on a new approach for SNP discrimination using toehold-mediated DNA strand displacement. The distinctiveness of the approach is based on the combination of both 3- and 4-way branch migration mechanisms, which allows for reliable discrimination of SNPs within doubl...

Enabling science and technology for marine renewable energy

International Nuclear Information System (INIS)

Mueller, Markus; Wallace, Robin

2008-01-01

This paper describes some of the key challenges to be met in the development of marine renewable energy technology, from its present prototype form to being a widely deployed contributor to future energy supply. Since 2000, a number of large-scale wave and tidal current prototypes have been demonstrated around the world, but marine renewable energy technology is still 10-15 years behind that of wind energy. UK-based developers are leading the way, with Pelamis from Pelamis Wave Power demonstrated in the open sea, generating electricity into the UK network and securing orders from Portugal. However, having started later, the developing technology can make use of more advanced science and engineering, and it is therefore reasonable to expect rapid progress. Although progress is underway through deployment and testing, there are still key scientific challenges to be addressed in areas including resource assessment and predictability, engineering design and manufacturability, installation, operation and maintenance, survivability, reliability and cost reduction. The research priorities required to meet these challenges are suggested in this paper and have been drawn from current roadmaps and vision documents, including more recent consultations within the community by the UK Energy Research Centre Marine Research Network. Many scientific advances are required to meet these challenges, and their likelihood is explored based on current and future capabilities

Structural features in the HIV-1 repeat region facilitate strand transfer during reverse transcription

NARCIS (Netherlands)

Berkhout, B.; Vastenhouw, N. L.; Klasens, B. I.; Huthoff, H.

2001-01-01

Two obligatory DNA strand transfers take place during reverse transcription of a retroviral RNA genome. The first strand transfer is facilitated by terminal repeat (R) elements in the viral genome. This strand-transfer reaction depends on base pairing between the cDNA of the 5'R and the 3'R. There

Strand Tension Control in Anchor Span for Suspension Bridge Using Dynamic Balance Theory

Directory of Open Access Journals (Sweden)

Da Wang

Full Text Available Abstract Strand tension control is essential in suspension bridge safety. However, few quantitative studies have examined the bending rigidity and boundary condition behavior of strands in the anchor span of suspension bridges because of their special structure and complex configuration. In this paper, a new calculation method for strand tension is explored by using dynamic balance theory to determine the effect of bending rigidity and boundary conditions. The accuracy and effectiveness of the proposed method are tested and confirmed with verification examples and application on Nanxi Yangtze Suspension Bridge in China. The results indicated that only low-order frequency calculation could be used to calculate the strand tension without considering the effect of bending rigidity to ensure control accuracy. The influence of bending rigidity on the control precision is related to the tension and the length of the strands, which is significantly determined by the specific value between the stress rigidity and the bending rigidity. The uncertain boundary conditions of the anchor span cable, which are fixed between consolidated and hinged, also have a major effect on the control accuracy. To improve the accuracy of strand tension control, the least squares method is proposed during the tension construction control of the anchor span. This approach can significantly improve the accuracy of the tension control of the main cable strand. Some recommendations for future bridge analysis are provided based on the results of this study.

Genetic analysis of RPA single-stranded DNA binding protein in Haloferax volcanii

OpenAIRE

Stroud, A. L.

2012-01-01

Replication protein A (RPA) is a single-stranded DNA-binding protein that is present in all three domains of life. The roles of RPA include stabilising and protecting single- stranded DNA from nuclease degradation during DNA replication and repair. To achieve this, RPA uses an oligosaccharide-binding fold (OB fold) to bind single- stranded DNA. Haloferax volcanii encodes three RPAs – RPA1, RPA2 and RPA3, of which rpa1 and rpa3 are in operons with genes encoding associated proteins (APs). ...

Genetic transformation of Neisseria gonorrhoeae shows a strand preference

OpenAIRE

Duffin, Paul M.; Seifert, H. Steven

2012-01-01

Natural transformation is the main means of horizontal genetic exchange in the obligate human pathogen Neisseria gonorrhoeae. Neisseria spp. have been shown to preferentially take up and transform their own DNA by recognizing a non-palindromic 10 or 12 nucleotide DNA uptake sequence (DUS10 or DUS12). We investigated the ability of the DUS12 to enhance single-stranded DNA (ssDNA) transformation. Given the non-palindromic nature of the DUS12, we tested whether both strands of the DUS equally en...

The Strategic Paradox of Social Networks

Science.gov (United States)

2011-03-18

United States claimed to have met online.9 And in 2010, Facebook claimed over 500 million users, which would make the social networking service the...service culture, or occupational specialty. One drawback with social networks concerns the protection of individual privacy. Facebook , for...St ra te gy R es ea rc h Pr oj ec t THE STRATEGIC PARADOX OF SOCIAL NETWORKS BY COLONEL ROBERT COTE United States Marine Corps

Using DNA origami nanostructures to determine absolute cross sections for UV photon-induced DNA strand breakage.

Science.gov (United States)

Vogel, Stefanie; Rackwitz, Jenny; Schürman, Robin; Prinz, Julia; Milosavljević, Aleksandar R; Réfrégiers, Matthieu; Giuliani, Alexandre; Bald, Ilko

2015-11-19

We have characterized ultraviolet (UV) photon-induced DNA strand break processes by determination of absolute cross sections for photoabsorption and for sequence-specific DNA single strand breakage induced by photons in an energy range from 6.50 to 8.94 eV. These represent the lowest-energy photons able to induce DNA strand breaks. Oligonucleotide targets are immobilized on a UV transparent substrate in controlled quantities through attachment to DNA origami templates. Photon-induced dissociation of single DNA strands is visualized and quantified using atomic force microscopy. The obtained quantum yields for strand breakage vary between 0.06 and 0.5, indicating highly efficient DNA strand breakage by UV photons, which is clearly dependent on the photon energy. Above the ionization threshold strand breakage becomes clearly the dominant form of DNA radiation damage, which is then also dependent on the nucleotide sequence.

Magnetization Losses of Roebel Cable Samples with 2G YBCO Coated Conductor Strands

CERN Document Server

Yang, Y.; Falorio, I.; Young, E.A.; Kario, A.; Goldacker, W.; Dhallé, M. M. J.; van Nugteren, J.; Kirby, G.; Bottura, L.; Ballarino, A.

2016-01-01

Roebel cable with 2G YBCO strands is one of the promising HTS solutions of fully transposed high current conductors for high field accelerator magnets. Following the considerable research effort on the manufacturing of Roebel cables in recent years, sample conductors are now available in useful lengths with reproducible performances to allow detailed characterizations beyond the standard critical current measurements. The ac loss and strands coupling are of significant interest for the field quality of the accelerator magnets. We report a set of systematic ac loss measurements on two different Roebel cable samples prepared for the EuCARD2 collaboration. The measurements were performed over a wide range of temperature between 5 K and 90 K and the results were analyzed in the context of strands architecture and coupling. The results show that the transposed bundles are partially decoupled and the strands in transposition sections behave as an isolated single tape if the strands are insulated.

Critical cooperation range to improve spatial network robustness.

Directory of Open Access Journals (Sweden)

Vitor H P Louzada

Full Text Available A robust worldwide air-transportation network (WAN is one that minimizes the number of stranded passengers under a sequence of airport closures. Building on top of this realistic example, here we address how spatial network robustness can profit from cooperation between local actors. We swap a series of links within a certain distance, a cooperation range, while following typical constraints of spatially embedded networks. We find that the network robustness is only improved above a critical cooperation range. Such improvement can be described in the framework of a continuum transition, where the critical exponents depend on the spatial correlation of connected nodes. For the WAN we show that, except for Australia, all continental networks fall into the same universality class. Practical implications of this result are also discussed.

Analytical model of the critical current of a bent Nb3Sn strand

International Nuclear Information System (INIS)

Koizumi, Norikiyo; Murakami, Haruyuki; Hemmi, Tsutomu; Nakajima, Hideo

2011-01-01

The critical current performance of a large Nb 3 Sn cable-in-conduit conductor (CICC) was degraded by periodic bending of strands due to a large transverse electromagnetic force. The degradation of each strand due to this bending should be evaluated in calculations of the critical current of a CICC, but a suitable model has not been developed yet. Therefore, the authors have developed a new analytical model which takes into account plastic deformation of copper and bronze and filament breakage. The calculated results were compared with test results for uniformly bent Nb 3 Sn bronze-route strands. The calculated results assuming a high transverse resistance model (HTRM) show good agreement with the test results, a finding which confirms the validity of the model. Because of a much shorter calculation time than for numerical simulation, the developed model seems much more practical for use in calculating the critical current performance of a Nb 3 Sn CICC. In addition, simulation results show that since the neutral axis of a bent strand shifts to the compressive side due to plastic deformation of the copper and bronze, and/or filament breakage, the strand is elongated by bending. This elongation may enhance the strand's critical current performance. Moreover, the calculated results indicate that the dependence of the critical current on the bending strain is affected by the bending history if the strand is excessively bent, especially when filaments are broken. In a real magnet, since a strand in a CICC is normally subject to the maximum electromagnetic force prior to an evaluation of its performance at a lower electromagnetic force, the effect of over-bending should be taken into account in calculations of its critical current performance, especially when filament breakage occurs.

Breaks in plasmid DNA strand induced by laser radiation at a wavelength of 193 nm

International Nuclear Information System (INIS)

Gurzadyan, G.G.; Shul'te Frolinde, D.

1996-01-01

DNA of plasmid pB322 irradiated with laser at a wavelength of 193 nm was treated with an extract containing proteins from E.coli K12 AB1157 (wild-type). The enzymes were found to produce single- and double-strand DNA breaks, which was interpreted as a transformation of a portion of cyclobutane pyrimidine dimers and (6-4) photoproducts into nonrepairable single-strand DNA breaks. The products resulted from ionization of DNA, in particular, single-strand breaks, transform to double-strand breaks. A comparison of these data with the data on survival of plasmid upon transformation of E.coli K12 AB1157 enables one to assess the biological significance of single- and double-strand breaks. The inactivation of the plasmid is mainly determined by the number of directly formed laser-induced single-strand breaks. 26 refs.; 2 figs

Paul Strand y las paradojas de la modernidad americana

Directory of Open Access Journals (Sweden)

Vicente Sánchez Biosca

2010-06-01

Full Text Available As contribuições de Strand para o cinema estão estreitamente relacionadas com seus trabalhos fotográficos da época e mesmo com um olhar que, apesar de suas múltiplas diferenças, possui muitos pontos em comum. Se em Manhatta (1920, Strand (em colaboração com Sheeler oferece uma síntese da natureza e da modernidade, em Redes (1934 o que predomina, em contrapartida, é a experiência da arte muralista mexicana e a influência de Eisenstein (em suas andanças por México são os fatores que determinam seus esforços na construção de uma épica dos operários. Mas sem dúvida, o projeto mais ambicioso de Strand (ao mando da produtora Frontier Films foi Native Land, o filme que atendeu às demandas do American Popular Front e as moldou nas palavras dos fundadores da pátria americana.

Radionuclides in marine mammals off the Portuguese coast

Energy Technology Data Exchange (ETDEWEB)

Malta, Margarida [Instituto Tecnologico e Nuclear, Departamento de Proteccao Radiologica e Seguranca Nuclear, E.N. 10, 2686-953 Sacavem (Portugal); Carvalho, Fernando P., E-mail: carvalho@itn.p [Instituto Tecnologico e Nuclear, Departamento de Proteccao Radiologica e Seguranca Nuclear, E.N. 10, 2686-953 Sacavem (Portugal)

2011-05-15

Radionuclide analyses were performed in tissue samples including muscle, gonad, liver, mammary gland, and bone of marine mammals stranded on the Portuguese west coast during January-July 2006. Tissues were collected from seven dolphins (Delphinus delphis and Stenella coeruleoalba) and one pilot whale (Globicephala sp.). Samples were analyzed for {sup 210}Po and {sup 210}Pb by alpha spectrometry and for {sup 137}Cs and {sup 40}K by gamma spectrometry. Po-210 concentrations in common dolphin's muscle (D. delphis) averaged 56 {+-} 32 Bq kg{sup -1} wet weight (w.w.), while {sup 210}Pb averaged 0.17 {+-} 0.07 Bq kg{sup -1} w.w., {sup 137}Cs averaged 0.29 {+-} 0.28 Bq kg{sup -1} w.w., and {sup 40}K 129 {+-} 48 Bq kg{sup -1} w.w. Absorbed radiation doses due to these radionuclides for the internal organs of common dolphins were computed and attained a 1.50 {mu}Gy h{sup -1} on a whole body basis. {sup 210}Po was the main contributor to the weighted absorbed dose, accounting for 97% of the dose from internally accumulated radionuclides. These computed radiation doses in dolphins are compared to radiation doses from {sup 210}Po and other radionuclides reported for human tissues. Due to the high {sup 210}Po activity concentration in dolphins, the internal radiation dose in these marine mammals is about three orders of magnitude higher than in man. - Highlights: {yields} In marine mammals the highest activity concentrations were those of {sup 40}K and {sup 210}Po. {yields} Absorbed radiation doses in dolphin tissues attained 1.50 mGy h{sup -1} on a whole body basis. {yields} Po-210 was the main contributor (97%) to the internal absorbed radiation dose. {yields} The high {sup 210}Po concentration in the marine mammal's tissues is due to food chain transfer. {yields} The absorbed radiation dose in dolphins is three orders of magnitude higher than in man.

Prevalence of Urogenital Carcinoma in Stranded California Sea Lions ( Zalophus Californianus) from 2005-2015.

Science.gov (United States)

Deming, Alissa C; Colegrove, Kathleen M; Duignan, Padraig J; Hall, Ailsa J; Wellehan, James F X; Gulland, Frances M D

2018-03-02

Urogenital carcinoma is common in wild California sea lions ( Zalophus californianus) along the west coast of the US. From 1979 to 1994, this cancer was observed in 18% (66/370) of necropsied subadult and adult sea lions at The Marine Mammal Center in Sausalito, California. A retrospective review of records from 1 January 2005 to 31 December 2015 was performed to characterize prevalence and characteristics of cancer over this decade. Fourteen percent (263/1917) of necropsied sea lions had cancer, of which 90% (237/263) were urogenital carcinoma. The prevalence of urogenital carcinoma was significantly higher in adults compared to juveniles and subadults. Advanced-stage disease with metastases was identified histologically in 78% (182/232) of cases and was the cause of death in 95% (172/182) of these cases. Metastases were most common in lung and lymph nodes, and hydronephrosis, secondary to ureter obstruction by metastases, was identified in 62% (114/185) of animals with advanced disease. No significant temporal change in prevalence was detected over the decade, and this highly aggressive, fatal cancer remains common in stranded California sea lions.

Environmental Monitoring Techniques and Equipment related to the installation and operation of Marine Energy Conversion Systems

International Nuclear Information System (INIS)

Scanu, Sergio; Carli, Filippo Maria; Piermattei, Viviana; Bonamano, Simone; Paladini de Mendoza, Francesco; Marcelli, Marco; Peviani, Maximo Aurelio; Dampney, Keith; Norris, Jennifer

2015-01-01

Results of activities under project Marine Renewables Infrastructure Network for Emerging Energy Technologies (MaRINET) are reported, which led to DEMTE, a database, created on the basis of standardized monitoring of the marine environment during installation, operation and decommissioning of Marine Energy Conversion Systems. Obtained with the consortium partners’ available techniques and equipment, the database shows that such instruments cover all identified marine environmental compartments, despite the lack of underwater vehicles and the reduced skills in using satellite technologies. These weaknesses could be overcome by an accurate planning of equipment, techniques and knowledge sharing. The approach here presented also leads to an effective analysis even in non-marine contexts

Navigating transformations in governance of Chilean marine coastal resources

Science.gov (United States)

Gelcich, Stefan; Hughes, Terry P.; Olsson, Per; Folke, Carl; Defeo, Omar; Fernández, Miriam; Foale, Simon; Gunderson, Lance H.; Rodríguez-Sickert, Carlos; Scheffer, Marten; Steneck, Robert S.; Castilla, Juan C.

2010-01-01

Marine ecosystems are in decline. New transformational changes in governance are urgently required to cope with overfishing, pollution, global changes, and other drivers of degradation. Here we explore social, political, and ecological aspects of a transformation in governance of Chile's coastal marine resources, from 1980 to today. Critical elements in the initial preparatory phase of the transformation were (i) recognition of the depletion of resource stocks, (ii) scientific knowledge on the ecology and resilience of targeted species and their role in ecosystem dynamics, and (iii) demonstration-scale experimental trials, building on smaller-scale scientific experiments, which identified new management pathways. The trials improved cooperation among scientists and fishers, integrating knowledge and establishing trust. Political turbulence and resource stock collapse provided a window of opportunity that triggered the transformation, supported by new enabling legislation. Essential elements to navigate this transformation were the ability to network knowledge from the local level to influence the decision-making processes at the national level, and a preexisting social network of fishers that provided political leverage through a national confederation of artisanal fishing collectives. The resultant governance scheme includes a revolutionary national system of marine tenure that allocates user rights and responsibilities to fisher collectives. Although fine tuning is necessary to build resilience of this new regime, this transformation has improved the sustainability of the interconnected social–ecological system. Our analysis of how this transformation unfolded provides insights into how the Chilean system could be further developed and identifies generalized pathways for improved governance of marine resources around the world. PMID:20837530

IHF-independent assembly of the Tn10 strand transfer transpososome: implications for inhibition of disintegration

OpenAIRE

Stewart, Barry J.; Wardle, Simon J.; Haniford, David B.

2002-01-01

The frequency of DNA transposition in transposition systems that employ a strand transfer step may be significantly affected by the occurrence of a disintegration reaction, a reaction that reverses the strand transfer event. We have asked whether disintegration occurs in the Tn10 transposition system. We show that disintegration substrates (substrates constituting one half of the strand transfer product) are assembled into a transpososome that mimics the strand transfer intermediate. This str...

Chirality induction and protonation-induced molecular motions in helical molecular strands.

Science.gov (United States)

Kolomiets, Elena; Berl, Volker; Lehn, Jean-Marie

2007-01-01

The long oligopyridinedicarboxamide strand 9, containing 15 heterocyclic rings has been synthesized and its helical structure determined by X-ray crystallography. It was shown that the shorter analogue 6 displays induced circular dichroism and amplification of induced chirality upon dissolution in an optically active solvent, diethyl-L-tartrate. A novel class of helical foldamers was prepared, strands 14-16, based on two oligopyridine carboxamide segments linked through a L-tartaric acid derived spacer. These tartro strands display internal chirality induction as well as chirality amplification. NMR spectroscopy (on 8 and 9) and circular dichroism (on 16) studies show that the oligopyridine carboxamide strands undergo reversible unfolding/folding upon protonation. The protonation-induced unfolding has been confirmed by X-ray crystallographic determination of the molecular structure of the extended protonated heptameric form 8(+). The molecular-scale mechano-chemical motions of the protonation-induced structural switching consist of a change of the length of the molecule, from 6 angstroms (6, coiled form) to 29 angstroms (8(+), uncoiled form) for the heptamer and from 12.5 angstroms (9, coiled form, X-ray structure) to 57 angstroms (9(+), uncoiled form, from modeling) for the pentadecamer. Similar unfolding/folding motional processes take place in the L-tartro strands 15 and 16 upon protonation/deprotonation, with loss of helicity-induced circular dichroism on unfolding as shown for the protonated form 16(+).

Evolutionary implications of inversions that have caused intra-strand parity in DNA

Directory of Open Access Journals (Sweden)

Wei John

2007-06-01

Full Text Available Abstract Background Chargaff's rule of DNA base composition, stating that DNA comprises equal amounts of adenine and thymine (%A = %T and of guanine and cytosine (%C = %G, is well known because it was fundamental to the conception of the Watson-Crick model of DNA structure. His second parity rule stating that the base proportions of double-stranded DNA are also reflected in single-stranded DNA (%A = %T, %C = %G is more obscure, likely because its biological basis and significance are still unresolved. Within each strand, the symmetry of single nucleotide composition extends even further, being demonstrated in the balance of di-, tri-, and multi-nucleotides with their respective complementary oligonucleotides. Results Here, we propose that inversions are sufficient to account for the symmetry within each single-stranded DNA. Human mitochondrial DNA does not demonstrate such intra-strand parity, and we consider how its different functional drivers may relate to our theory. This concept is supported by the recent observation that inversions occur frequently. Conclusion Along with chromosomal duplications, inversions must have been shaping the architecture of genomes since the origin of life.

Time-dependent evolution of strand transfer length in pretensioned prestressed concrete members

Science.gov (United States)

Caro, L. A.; Martí-Vargas, J. R.; Serna, P.

2013-11-01

For design purposes, it is generally considered that prestressing strand transfer length does not change with time. However, some experimental studies on the effect of time on transfer lengths show contradictory results. In this paper, an experimental research to study transfer length changes over time is presented. A test procedure based on the ECADA testing technique to measure prestressing strand force variation over time in pretensioned prestressed concrete specimens has been set up. With this test method, an experimental program that varies concrete strength, specimen cross section, age of release, prestress transfer method, and embedment length has been carried out. Both the initial and long-term transfer lengths of 13-mm prestressing steel strands have been measured. The test results show that transfer length variation exists for some prestressing load conditions, resulting in increased transfer length over time. The applied test method based on prestressing strand force measurements has shown more reliable results than procedures based on measuring free end slips and longitudinal strains of concrete. An additional factor for transfer length models is proposed in order to include the time-dependent evolution of strand transfer length in pretensioned prestressed concrete members.

Sequential strand displacement beacon for detection of DNA coverage on functionalized gold nanoparticles.

Science.gov (United States)

Paliwoda, Rebecca E; Li, Feng; Reid, Michael S; Lin, Yanwen; Le, X Chris

2014-06-17

Functionalizing nanomaterials for diverse analytical, biomedical, and therapeutic applications requires determination of surface coverage (or density) of DNA on nanomaterials. We describe a sequential strand displacement beacon assay that is able to quantify specific DNA sequences conjugated or coconjugated onto gold nanoparticles (AuNPs). Unlike the conventional fluorescence assay that requires the target DNA to be fluorescently labeled, the sequential strand displacement beacon method is able to quantify multiple unlabeled DNA oligonucleotides using a single (universal) strand displacement beacon. This unique feature is achieved by introducing two short unlabeled DNA probes for each specific DNA sequence and by performing sequential DNA strand displacement reactions. Varying the relative amounts of the specific DNA sequences and spacing DNA sequences during their coconjugation onto AuNPs results in different densities of the specific DNA on AuNP, ranging from 90 to 230 DNA molecules per AuNP. Results obtained from our sequential strand displacement beacon assay are consistent with those obtained from the conventional fluorescence assays. However, labeling of DNA with some fluorescent dyes, e.g., tetramethylrhodamine, alters DNA density on AuNP. The strand displacement strategy overcomes this problem by obviating direct labeling of the target DNA. This method has broad potential to facilitate more efficient design and characterization of novel multifunctional materials for diverse applications.

Research on export system of marine nuclear power device

International Nuclear Information System (INIS)

Fu Mingyu; Bian Xinqian; Shi Ji; Xin Chengdong; Wei Dong

2002-01-01

A marine nuclear power plant simulation system is founded, and a management expert system, which can administer and diagnose the typical faults, is constituted by the intelligent expert theory. This real-time expert system can analyze the reason of the typical fault caused by the nuclear power plant practically running and give the best solvent by the expert knowledge reasoning in the repository; a neural network fault inspection and diagnosis expert system which can inspect every equipment continually and give the faults diagnosis result based on the inspective dates is established. Based on the three hierarchical architecture, the operation performance is improved very much by using of the neural network fault inspection and diagnosis expert system to inspect and diagnose the nuclear power plant faults and the management expert system to supervise the nuclear power plant running. The expert system research can give guidance for the marine nuclear power plant safety operation

Comparison Between Nb3Al and Nb3Sn Strands and Cables for High Field Accelerator Magnets

Energy Technology Data Exchange (ETDEWEB)

Yamada, R.; Kikuchi, A.; Barzi, E.; Chlachidze, G.; Rusy, A.; Takeuchi, T.; Tartaglia, M.; Turrioni, D.; Velev, V.; Wake, M.; Zlobin, A.V.; /Fermilab

2010-01-01

The Nb{sub 3}Al small racetrack magnet, SR07, has been successfully built and tested to its short sample limit beyond 10 Tesla without any training. Thus the practical application of Nb{sub 3}Al strands for high field accelerator magnets is established. The characteristics of the representative F4 strand and cable, are compared with the typical Nb{sub 3}Sn strand and cable. It is represented by the OST high current RRP Nb{sub 3}Sn strand with 108/127 configuration. The effects of Rutherford cabling to both type strands are explained and the inherent problem of the Nb{sub 3}Sn strand is discussed. Also the test results of two representative small racetrack magnets are compared from the stand point of Ic values, and training. The maximum current density of the Nb{sub 3}Al strands is still smaller than that of the Nb{sub 3}Sn strands, but if we take into account of the stress-strain characteristics, Nb{sub 3}Al strands become somewhat favorable in some applications.

Systems pharmacology-based drug discovery for marine resources: an example using sea cucumber (Holothurians).

Science.gov (United States)

Guo, Yingying; Ding, Yan; Xu, Feifei; Liu, Baoyue; Kou, Zinong; Xiao, Wei; Zhu, Jingbo

2015-05-13

Sea cucumber, a kind of marine animal, have long been utilized as tonic and traditional remedies in the Middle East and Asia because of its effectiveness against hypertension, asthma, rheumatism, cuts and burns, impotence, and constipation. In this study, an overall study performed on sea cucumber was used as an example to show drug discovery from marine resource by using systems pharmacology model. The value of marine natural resources has been extensively considered because these resources can be potentially used to treat and prevent human diseases. However, the discovery of drugs from oceans is difficult, because of complex environments in terms of composition and active mechanisms. Thus, a comprehensive systems approach which could discover active constituents and their targets from marine resource, understand the biological basis for their pharmacological properties is necessary. In this study, a feasible pharmacological model based on systems pharmacology was established to investigate marine medicine by incorporating active compound screening, target identification, and network and pathway analysis. As a result, 106 candidate components of sea cucumber and 26 potential targets were identified. Furthermore, the functions of sea cucumber in health improvement and disease treatment were elucidated in a holistic way based on the established compound-target and target-disease networks, and incorporated pathways. This study established a novel strategy that could be used to explore specific active mechanisms and discover new drugs from marine sources. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Survey on the presence of non-dioxine-like PCBs (NDL-PCBs) in loggerhead turtles (Caretta caretta) stranded in south Mediterranean coasts (Sicily, Southern Italy).

Science.gov (United States)

Cammilleri, Gaetano; Calvaruso, Enza; Pantano, Licia; Cascio, Giovanni Lo; Randisi, Barbara; Macaluso, Andrea; Vazzana, Mirella; Caracappa, Giulia; Giangrosso, Giuseppe; Vella, Antonio; Ferrantelli, Vincenzo

2017-11-01

A total of 71 loggerhead turtles (Caretta caretta) stranded along the coasts of Sicily (Southern Italy) were examined for non-dioxine like polychlorinated biphenyl (NDL-PCB) levels in muscle and adipose tissue by a gas chromatography-mass spectrometry/mass spectrometry (GC-MS/MS) method. The results revealed 6 high-indicator congener (∑ 6 PCB IND ) levels in 45% of the loggerhead turtles examined, with mean values of 980.39 ± 2508.39 ng/g wet weight in adipose tissue and 102.53 ± 238.58 ng/g wet weight in muscle tissue. The hexachloro and heptachloro PCB congeners were the most abundant in both the sample types. The highest NDL-PCB levels were reached in an adipose tissue sample of a loggerhead turtle of 80 kg stranded along the coasts of Termini Imerese (14 183.85 ng/g wet wt). No significant correlation was found between modified Fulton's K values of the loggerhead turtles and PCB contents (S = 47 151, p > 0.05). Furthermore, no significant differences were found between sexes (W = 365, p >  0.05). The PCB levels found in the present study were much higher than those found in the literature. The present study is the first report on the existence of NDL-PCBs in loggerhead turtles stranded in Sicilian coasts confirming C. caretta as a valuable indicator of contaminant exposure in the marine environment because of their specific biological and ecological characteristics. Environ Toxicol Chem 2017;36:2997-3002. © 2017 SETAC. © 2017 SETAC.

Missing Strands? Dealing with Hair Loss

Science.gov (United States)

... 2017 Print this issue Missing Strands? Dealing with Hair Loss En español Send us your comments Hair loss is often associated with men and aging, but ... or their treatments, and many other things cause hair loss. The most common type of hair loss is ...

Bridging Organizations Drive Effective Governance Outcomes for Conservation of Indonesia’s Marine Systems

Science.gov (United States)

Berdej, Samantha M.; Armitage, Derek R.

2016-01-01

This study empirically investigates the influence of bridging organizations on governance outcomes for marine conservation in Indonesia. Conservation challenges require ways of governing that are collaborative and adaptive across boundaries, and where conservation actions are better coordinated, information flows improved, and knowledge better integrated and mobilized. We combine quantitative social network analysis and qualitative data to analyze bridging organizations and their networks, and to understand their contributions and constraints in two case studies in Bali, Indonesia. The analysis shows 1) bridging organizations help to navigate the ‘messiness’ inherent in conservation settings by compensating for sparse linkages, 2) the particular structure and function of bridging organizations influence governing processes (i.e., collaboration, knowledge sharing) and subsequent conservation outcomes, 3) ‘bridging’ is accomplished using different strategies and platforms for collaboration and social learning, and 4) bridging organizations enhance flexibility to adjust to changing marine conservation contexts and needs. Understanding the organizations that occupy bridging positions, and how they utilize their positionality in a governance network is emerging as an important determinant of successful conservation outcomes. Our findings contribute to a relatively new body of literature on bridging organizations in marine conservation contexts, and add needed empirical investigation into their value to governance and conservation in Coral Triangle nations and beyond. PMID:26794003

Influence of oxidized purine processing on strand directionality of mismatch repair.

Science.gov (United States)

Repmann, Simone; Olivera-Harris, Maite; Jiricny, Josef

2015-04-17

Replicative DNA polymerases are high fidelity enzymes that misincorporate nucleotides into nascent DNA with a frequency lower than [1/10(5)], and this precision is improved to about [1/10(7)] by their proofreading activity. Because this fidelity is insufficient to replicate most genomes without error, nature evolved postreplicative mismatch repair (MMR), which improves the fidelity of DNA replication by up to 3 orders of magnitude through correcting biosynthetic errors that escaped proofreading. MMR must be able to recognize non-Watson-Crick base pairs and excise the misincorporated nucleotides from the nascent DNA strand, which carries by definition the erroneous genetic information. In eukaryotes, MMR is believed to be directed to the nascent strand by preexisting discontinuities such as gaps between Okazaki fragments in the lagging strand or breaks in the leading strand generated by the mismatch-activated endonuclease of the MutL homologs PMS1 in yeast and PMS2 in vertebrates. We recently demonstrated that the eukaryotic MMR machinery can make use also of strand breaks arising during excision of uracils or ribonucleotides from DNA. We now show that intermediates of MutY homolog-dependent excision of adenines mispaired with 8-oxoguanine (G(O)) also act as MMR initiation sites in extracts of human cells or Xenopus laevis eggs. Unexpectedly, G(O)/C pairs were not processed in these extracts and failed to affect MMR directionality, but extracts supplemented with exogenous 8-oxoguanine DNA glycosylase (OGG1) did so. Because OGG1-mediated excision of G(O) might misdirect MMR to the template strand, our findings suggest that OGG1 activity might be inhibited during MMR. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Study in regularities in the formation of double stranded DNA breaks in irradiated rat thymocytes

International Nuclear Information System (INIS)

Ivannik, B.P.; ProskuryakoV, S.Ya.; Ryabchenko, N.I.

1979-01-01

Using low-gradient viscosimetry of neutral detergent nuclear lysates a study was made of postradiation changes in the molecular weight of double-stranded DNA of thymocytes. It was established that 375 eV are needed for one double-stranded break to appear, and a dose of 1 rad is required for 0.275 double-stranded break to occur at the site of DNA with m.w. 10 12 dalton. The repair of double-stranded breaks is only observed when rats are exposed to a dose of 500 R. It is assumed that the absence of repair of double-stranded DNA breaks and the presence of secondary postradiation degradation of DNA are responsible for thymocyte death

Velocity and processivity of helicase unwinding of double-stranded nucleic acids

International Nuclear Information System (INIS)

Betterton, M D; Juelicher, F

2005-01-01

Helicases are molecular motors which unwind double-stranded nucleic acids (dsNA) in cells. Many helicases move with directional bias on single-stranded (ss) nucleic acids, and couple their directional translocation to strand separation. A model of the coupling between translocation and unwinding uses an interaction potential to represent passive and active helicase mechanisms. A passive helicase must wait for thermal fluctuations to open dsNA base pairs before it can advance and inhibit NA closing. An active helicase directly destabilizes dsNA base pairs, accelerating the opening rate. Here we extend this model to include helicase unbinding from the nucleic-acid strand. The helicase processivity depends on the form of the interaction potential. A passive helicase has a mean attachment time which does not change between ss translocation and ds unwinding, while an active helicase in general shows a decrease in attachment time during unwinding relative to ss translocation. In addition, we describe how helicase unwinding velocity and processivity vary if the base-pair binding free energy is changed

Enzymatic induction of DNA double-strand breaks in γ-irradiated Escherichia coli K-12

International Nuclear Information System (INIS)

Bonura, T.; Smith, K.C.; Kaplan, H.S.

1975-01-01

The polA1 mutation increases the sensitivity of E. coli K-12 to killing by γ-irradiation in air by a factor of 2.9 and increases the yield of DNA double-strand breaks by a factor of 2.5. These additional DNA double-strand breaks appear to be due to the action of nucleases in the polA1 strain rather than to the rejoining of radiation-induced double-strand breaks in the pol + strain. This conclusion is based upon the observation that γ-irradiation at 3 0 did not affect the yield of DNA double-strand breaks in the pol + strain, but decreased the yield in the polA1 strain by a factor of 2.2. Irradiation of the polA1 strain at 3 0 followed by incubation at 3 0 for 20 min before plating resulted in approximately a 1.5-fold increase in the D 0 . The yield of DNA double-strand breaks was reduced by a factor of 1.5. The pol + strain, however, did not show the protective effect of the low temperature incubation upon either survival or DNA double-strand breakage. We suggest that the increased yield of DNA double-strand breaks in the polA 1 strain may be the result of the unsuccessful excision repair of ionizing radiation-induced dna base damage

Three methods to determine the yields of DNA double-strand breaks

International Nuclear Information System (INIS)

Erzgraeber, G.; Lapidus, I.L.

1985-01-01

A possibility of determining the yield of DNA double-strand breaks in cells of the Chinese hamster (V79-4) by finding the amount of DNA released as a result of breaks and by determining the relative sedimentation velocity of DNA-membrane complexes affected by ionizing radiations with different physical characteristics is discussed. Results of the analysis are compared with the data obtained by a traditional method of sedimentation in the neutral sucrose density gradient. Comparative characterization of the methods is discussed. The yields of DNA double-strand breaks determined by the suggested independent methods are in good agreement, which opens possibilities of studying induction and repair of double-strand breaks by means of simpler and more reliable methods

RNA STRAND: The RNA Secondary Structure and Statistical Analysis Database

Directory of Open Access Journals (Sweden)

Andronescu Mirela

2008-08-01

Full Text Available Abstract Background The ability to access, search and analyse secondary structures of a large set of known RNA molecules is very important for deriving improved RNA energy models, for evaluating computational predictions of RNA secondary structures and for a better understanding of RNA folding. Currently there is no database that can easily provide these capabilities for almost all RNA molecules with known secondary structures. Results In this paper we describe RNA STRAND – the RNA secondary STRucture and statistical ANalysis Database, a curated database containing known secondary structures of any type and organism. Our new database provides a wide collection of known RNA secondary structures drawn from public databases, searchable and downloadable in a common format. Comprehensive statistical information on the secondary structures in our database is provided using the RNA Secondary Structure Analyser, a new tool we have developed to analyse RNA secondary structures. The information thus obtained is valuable for understanding to which extent and with which probability certain structural motifs can appear. We outline several ways in which the data provided in RNA STRAND can facilitate research on RNA structure, including the improvement of RNA energy models and evaluation of secondary structure prediction programs. In order to keep up-to-date with new RNA secondary structure experiments, we offer the necessary tools to add solved RNA secondary structures to our database and invite researchers to contribute to RNA STRAND. Conclusion RNA STRAND is a carefully assembled database of trusted RNA secondary structures, with easy on-line tools for searching, analyzing and downloading user selected entries, and is publicly available at http://www.rnasoft.ca/strand.

Comparison of DNA strand-break simulated with different DNA models

International Nuclear Information System (INIS)

Xie, Wenzhang; Li, Junli; Qiu, Rui; Yan, Congchong; Zeng, Zhi; Li, Chunyan

2013-01-01

Full text of the publication follows. In Monte Carlo simulation of DNA damage, the geometric model of DNA is of great importance. To study the influence of DNA model on the simulation of DNA damage, three DNA models were created in this paper. They were a volume model and two atomic models with different parameters. Direct DNA strand-break induced by low-energy electrons were simulated respectively with the three models. The results show that most of the energy depositions in the DNA segments do not lead to strand-breaks. The simple single strand-break (SSB) tends to be the predominant damage type, and the contribution of complex double strand-break (DSB) to the total DSB cannot be neglected. Among the yields of all the three DNA target models applied here, the yields of the volume model are the highest, the yields of the atomic model with double van der Waals radii (r) take the second place, whereas the yields of the atomic model with single r come last. On average, the ratios of SSB yields are approximately equivalent to the corresponding ratios of the models' volume. However, there seems to be no clear relationship between the DSB yields and the models' volume. (authors)

Multiple pathways of DNA double-strand break processing in a mutant Indian muntjac cell line

International Nuclear Information System (INIS)

Bouffler, S.D.; Jha, B.; Johnson, R.T.

1990-01-01

DNA break processing is compared in the Indian muntjac cell lines, SVM and DM. The initial frequencies and resealing of X-ray generated single- and double-strand breaks are similar in the two cell lines. Inhibiting the repair of UV damage leads to greater double-strand breakage in SVM than in DM, and some of these breaks are not repaired; however, repair-associated single-strand breakage and resealing are normal. Dimethylsulfate also induces excess double-strand breakage in SVM, and these breaks are irreparable. Restricted plasmids are reconstituted correctly in SVM at approximately 30% of the frequency observed in DM. Thus SVM has a reduced capacity to repair certain types of double-strand break. This defect is not due to a DNA ligase deficiency. We conclude that DNA double-strand breaks are repaired by a variety of pathways within mammalian cells and that the structure of the break or its mode of formation determines its subsequent fate

Withdrawal Strength of Dowels in Plywood and Oriented Strand Board

OpenAIRE

ERDİL, Yusuf Z.; ECKELMAN, Carl A.

2001-01-01

Plywood and oriented strand board (OSB) are being used increasingly in the construction of upholstered furniture frames. Yet there is little information available concerning the holding strength of various fasteners, and, in particular, dowels in these materials. A study was conducted accordingly, to obtain basic information about the holding strength of dowels in both plywood and oriented strand board. Results of the tests were incorporated into predictive expressions that allow designers to...

Dynamics of DNA replication loops reveal temporal control of lagging-strand synthesis

NARCIS (Netherlands)

Hamdan, Samir M.; Loparo, Joseph J.; Takahashi, Masateru; Richardson, Charles C.; Oijen, Antoine M. van

2009-01-01

In all organisms, the protein machinery responsible for the replication of DNA, the replisome, is faced with a directionality problem. The antiparallel nature of duplex DNA permits the leading-strand polymerase to advance in a continuous fashion, but forces the lagging-strand polymerase to

Human Cell Assays for Synthesis-Dependent Strand Annealing and Crossing over During Double-Strand Break Repair.

Science.gov (United States)

Zapotoczny, Grzegorz; Sekelsky, Jeff

2017-04-03

DNA double-strand breaks (DSBs) are one of the most deleterious types of lesions to the genome. Synthesis-dependent strand annealing (SDSA) is thought to be a major pathway of DSB repair, but direct tests of this model have only been conducted in budding yeast and Drosophila To better understand this pathway, we developed an SDSA assay for use in human cells. Our results support the hypothesis that SDSA is an important DSB repair mechanism in human cells. We used siRNA knockdown to assess the roles of a number of helicases suggested to promote SDSA. None of the helicase knockdowns reduced SDSA, but knocking down BLM or RTEL1 increased SDSA. Molecular analysis of repair products suggests that these helicases may prevent long-tract repair synthesis. Since the major alternative to SDSA (repair involving a double-Holliday junction intermediate) can lead to crossovers, we also developed a fluorescent assay that detects crossovers generated during DSB repair. Together, these assays will be useful in investigating features and mechanisms of SDSA and crossover pathways in human cells. Copyright © 2017 Zapotoczny and Sekelsky.

Human Cell Assays for Synthesis-Dependent Strand Annealing and Crossing over During Double-Strand Break Repair

Directory of Open Access Journals (Sweden)

Grzegorz Zapotoczny

2017-04-01

Full Text Available DNA double-strand breaks (DSBs are one of the most deleterious types of lesions to the genome. Synthesis-dependent strand annealing (SDSA is thought to be a major pathway of DSB repair, but direct tests of this model have only been conducted in budding yeast and Drosophila. To better understand this pathway, we developed an SDSA assay for use in human cells. Our results support the hypothesis that SDSA is an important DSB repair mechanism in human cells. We used siRNA knockdown to assess the roles of a number of helicases suggested to promote SDSA. None of the helicase knockdowns reduced SDSA, but knocking down BLM or RTEL1 increased SDSA. Molecular analysis of repair products suggests that these helicases may prevent long-tract repair synthesis. Since the major alternative to SDSA (repair involving a double-Holliday junction intermediate can lead to crossovers, we also developed a fluorescent assay that detects crossovers generated during DSB repair. Together, these assays will be useful in investigating features and mechanisms of SDSA and crossover pathways in human cells.

Adaptive Sampling in Autonomous Marine Sensor Networks

National Research Council Canada - National Science Library

Eickstedt, Donald P

2006-01-01

... oceanographic network scenario. This architecture has three major components, an intelligent, logical sensor that provides high-level environmental state information to a behavior-based autonomous vehicle control system, a new...

Evolutionary dynamics of adult stem cells: comparison of random and immortal-strand segregation mechanisms.

Science.gov (United States)

Tannenbaum, Emmanuel; Sherley, James L; Shakhnovich, Eugene I

2005-04-01

This paper develops a point-mutation model describing the evolutionary dynamics of a population of adult stem cells. Such a model may prove useful for quantitative studies of tissue aging and the emergence of cancer. We consider two modes of chromosome segregation: (1) random segregation, where the daughter chromosomes of a given parent chromosome segregate randomly into the stem cell and its differentiating sister cell and (2) "immortal DNA strand" co-segregation, for which the stem cell retains the daughter chromosomes with the oldest parent strands. Immortal strand co-segregation is a mechanism, originally proposed by [Cairns Nature (London) 255, 197 (1975)], by which stem cells preserve the integrity of their genomes. For random segregation, we develop an ordered strand pair formulation of the dynamics, analogous to the ordered strand pair formalism developed for quasispecies dynamics involving semiconservative replication with imperfect lesion repair (in this context, lesion repair is taken to mean repair of postreplication base-pair mismatches). Interestingly, a similar formulation is possible with immortal strand co-segregation, despite the fact that this segregation mechanism is age dependent. From our model we are able to mathematically show that, when lesion repair is imperfect, then immortal strand co-segregation leads to better preservation of the stem cell lineage than random chromosome segregation. Furthermore, our model allows us to estimate the optimal lesion repair efficiency for preserving an adult stem cell population for a given period of time. For human stem cells, we obtain that mispaired bases still present after replication and cell division should be left untouched, to avoid potentially fixing a mutation in both DNA strands.

Nitrate concentrations in drainage water in marine clay areas : exploratory research of the causes of increased nitrate concentrations

NARCIS (Netherlands)

Boekel, van E.M.P.M.; Roelsma, J.; Massop, H.T.L.; Hendriks, R.F.A.; Goedhart, P.W.; Jansen, P.C.

2013-01-01

The nitrate concentrations measured in drainage water and groundwater at LMM farms (farms participating in the National Manure Policy Effects Measurement Network (LLM)) in marine clay areas have decreased with 50% since the mid-nineties. The nitrate concentrations in marine clay areas are on average

The percentage of bacterial genes on leading versus lagging strands is influenced by multiple balancing forces

Science.gov (United States)

Mao, Xizeng; Zhang, Han; Yin, Yanbin; Xu, Ying

2012-01-01

The majority of bacterial genes are located on the leading strand, and the percentage of such genes has a large variation across different bacteria. Although some explanations have been proposed, these are at most partial explanations as they cover only small percentages of the genes and do not even consider the ones biased toward the lagging strand. We have carried out a computational study on 725 bacterial genomes, aiming to elucidate other factors that may have influenced the strand location of genes in a bacterium. Our analyses suggest that (i) genes of some functional categories such as ribosome have higher preferences to be on the leading strands; (ii) genes of some functional categories such as transcription factor have higher preferences on the lagging strands; (iii) there is a balancing force that tends to keep genes from all moving to the leading and more efficient strand and (iv) the percentage of leading-strand genes in an bacterium can be accurately explained based on the numbers of genes in the functional categories outlined in (i) and (ii), genome size and gene density, indicating that these numbers implicitly contain the information about the percentage of genes on the leading versus lagging strand in a genome. PMID:22735706

Fine-grained visual marine vessel classification for coastal surveillance and defense applications

Science.gov (United States)

Solmaz, Berkan; Gundogdu, Erhan; Karaman, Kaan; Yücesoy, Veysel; Koç, Aykut

2017-10-01

The need for capabilities of automated visual content analysis has substantially increased due to presence of large number of images captured by surveillance cameras. With a focus on development of practical methods for extracting effective visual data representations, deep neural network based representations have received great attention due to their success in visual categorization of generic images. For fine-grained image categorization, a closely related yet a more challenging research problem compared to generic image categorization due to high visual similarities within subgroups, diverse applications were developed such as classifying images of vehicles, birds, food and plants. Here, we propose the use of deep neural network based representations for categorizing and identifying marine vessels for defense and security applications. First, we gather a large number of marine vessel images via online sources grouping them into four coarse categories; naval, civil, commercial and service vessels. Next, we subgroup naval vessels into fine categories such as corvettes, frigates and submarines. For distinguishing images, we extract state-of-the-art deep visual representations and train support-vector-machines. Furthermore, we fine tune deep representations for marine vessel images. Experiments address two scenarios, classification and verification of naval marine vessels. Classification experiment aims coarse categorization, as well as learning models of fine categories. Verification experiment embroils identification of specific naval vessels by revealing if a pair of images belongs to identical marine vessels by the help of learnt deep representations. Obtaining promising performance, we believe these presented capabilities would be essential components of future coastal and on-board surveillance systems.

Postreplicational formation and repair of DNA double-strand breaks in UV-irradiated Escherichia coli uvrB cells

International Nuclear Information System (INIS)

Wang, Tzuchien V.; Smith, K.C.

1986-01-01

The number of DNA double-strand breaks formed in UV-irradiated uvrB recF recB cells correlates with the number of unrepaired DNA daughter-strand gaps, and is dependent on DNA synthesis after UV-irradiation. These results are consistent with the model that the DNA double-strand breaks that are produced in UV-irradiated excision-deficient cells occur as the result of breaks in the parental DNA opposite unrepaired DNA daughter-strand gaps. By employing a temperature-sensitive recA200 mutation, we have devised an improved assay for studying the formation and repair of these DNA double-strand breaks. Possible mechanisms for the postreplication repair of DNA double-strand breaks are discussed. (Auth.)

Probing electronic coupling between adenine bases in RNA strands from synchrotron radiation circular dichroism experiments

DEFF Research Database (Denmark)

Nielsen, Lisbeth Munksgård; Hoffmann, Søren Vrønning; Nielsen, Steen Brøndsted

2012-01-01

Circular dichroism spectra (176–330 nm) of RNA adenine oligomers, (rA)n (n = 1–10, 12, 15, and 20), reveal electronic coupling between two bases in short strands. The number of interacting bases in long strands is more and larger than that reported previously for the corresponding DNA strands....

Transmission pricing and stranded costs in the electric power industry

International Nuclear Information System (INIS)

Baumol, W.J.; Sidak, J.G.

1995-09-01

Stranded costs are those costs that electric utilities are currently permitted to recover through their rates but whose recovery may be impeded or prevented by the advent of competition in the industry. Estimates of these costs run from the tens to the hundreds of billions of dollars. Should regulators permit utilities to recover stranded costs while they take steps to promote competition in the electric power industry. William Baumol and J. Gregory Sidak argue that answer to that question should be yes.The authors show that a transmission price, the price for sending electricity over the transmission grid, can be determined in a manner that is compatible with economic efficiency and clearly neutral in its effects upon all competitors in electricity generation. A correctly constructed regime of transmission pricing may in fact achieve the efficiency and equity goals that justify the recovery of stranded costs

Informal Science learning in PIBID: identifying and interpreting the strands

Directory of Open Access Journals (Sweden)

Thomas Barbosa Fejolo

2013-10-01

Full Text Available This paper presents a research on informal Science learning in the context of the Institutional Scholarship Program Initiation to Teaching (PIBID. We take as reference the strands of informal Science learning (FAC, representing six dimensions of learning, they are: 1 Development of interest in Science; 2 Understanding of scientific knowledge; 3 Engaging in scientific reasoning; 4 Reflection on Science; 5 Engagement in scientific practice; 6 Identification with Science. For the lifting data, it was used the filming record of the interactions and dialogues of undergraduate students while performing activities of Optical Spectroscopy in the laboratory. Based on the procedures of content analysis and interpretations through communication, we investigate which of the six strands were present during the action of the students in activities. As a result we have drawn a learning profile for each student by distributing communications in different strands of informal Science learning.

7 CFR 1755.370 - RUS specification for seven wire galvanized steel strand.

Science.gov (United States)

2010-01-01

... 7 Agriculture 11 2010-01-01 2010-01-01 false RUS specification for seven wire galvanized steel..., ACCEPTABLE MATERIALS, AND STANDARD CONTRACT FORMS § 1755.370 RUS specification for seven wire galvanized... Steel Wire Strand, issued May 1978. All seven wire galvanized steel strand purchased after April 1, 1990...

Norwegian Ocean Observatory Network (NOON)

Science.gov (United States)

Ferré, Bénédicte; Mienert, Jürgen; Winther, Svein; Hageberg, Anne; Rune Godoe, Olav; Partners, Noon

2010-05-01

The Norwegian Ocean Observatory Network (NOON) is led by the University of Tromsø and collaborates with the Universities of Oslo and Bergen, UniResearch, Institute of Marine Research, Christian Michelsen Research and SINTEF. It is supported by the Research Council of Norway and oil and gas (O&G) industries like Statoil to develop science, technology and new educational programs. Main topics relate to ocean climate and environment as well as marine resources offshore Norway from the northern North Atlantic to the Arctic Ocean. NOON's vision is to bring Norway to the international forefront in using cable based ocean observatory technology for marine science and management, by establishing an infrastructure that enables real-time and long term monitoring of processes and interactions between hydrosphere, geosphere and biosphere. This activity is in concert with the EU funded European Strategy Forum on Research Infrastructures (ESFRI) roadmap and European Multidisciplinary Seafloor Observation (EMSO) project to attract international leading research developments. NOON envisions developing towards a European Research Infrastructure Consortium (ERIC). Beside, the research community in Norway already possesses a considerable marine infrastructure that can expand towards an international focus for real-time multidisciplinary observations in times of rapid climate change. PIC The presently established cable-based fjord observatory, followed by the establishment of a cable-based ocean observatory network towards the Arctic from an O&G installation, will provide invaluable knowledge and experience necessary to make a successful larger cable-based observatory network at the Norwegian and Arctic margin (figure 1). Access to large quantities of real-time observation from the deep sea, including high definition video, could be used to provide the public and future recruits to science a fascinating insight into an almost unexplored part of the Earth beyond the Arctic Circle

Enhanced Strain Measurement Range of an FBG Sensor Embedded in Seven-Wire Steel Strands.

Science.gov (United States)

Kim, Jae-Min; Kim, Chul-Min; Choi, Song-Yi; Lee, Bang Yeon

2017-07-18

FBG sensors offer many advantages, such as a lack of sensitivity to electromagnetic waves, small size, high durability, and high sensitivity. However, their maximum strain measurement range is lower than the yield strain range (about 1.0%) of steel strands when embedded in steel strands. This study proposes a new FBG sensing technique in which an FBG sensor is recoated with polyimide and protected by a polyimide tube in an effort to enhance the maximum strain measurement range of FBG sensors embedded in strands. The validation test results showed that the proposed FBG sensing technique has a maximum strain measurement range of 1.73% on average, which is 1.73 times higher than the yield strain of the strands. It was confirmed that recoating the FBG sensor with polyimide and protecting the FBG sensor using a polyimide tube could effectively enhance the maximum strain measurement range of FBG sensors embedded in strands.

Reconstitution of a eukaryotic replisome reveals suppression mechanisms that define leading/lagging strand operation

Science.gov (United States)

Georgescu, Roxana E; Schauer, Grant D; Yao, Nina Y; Langston, Lance D; Yurieva, Olga; Zhang, Dan; Finkelstein, Jeff; O'Donnell, Mike E

2015-01-01

We have reconstituted a eukaryotic leading/lagging strand replisome comprising 31 distinct polypeptides. This study identifies a process unprecedented in bacterial replisomes. While bacteria and phage simply recruit polymerases to the fork, we find that suppression mechanisms are used to position the distinct eukaryotic polymerases on their respective strands. Hence, Pol ε is active with CMG on the leading strand, but it is unable to function on the lagging strand, even when Pol δ is not present. Conversely, Pol δ-PCNA is the only enzyme capable of extending Okazaki fragments in the presence of Pols ε and α. We have shown earlier that Pol δ-PCNA is suppressed on the leading strand with CMG (Georgescu et al., 2014). We propose that CMG, the 11-subunit helicase, is responsible for one or both of these suppression mechanisms that spatially control polymerase occupancy at the fork. DOI: http://dx.doi.org/10.7554/eLife.04988.001 PMID:25871847

Using Marine and Freshwater Fish Environmental Intelligence Networks Under Different Climate Change Scenarios to Evaluate the Effectiveness of the Minamata Convention on Mercury

Science.gov (United States)

Bank, M. S.

2017-12-01

The Minamata Convention on Mercury was recently ratified and will go into effect on August 16, 2017. As noted in the convention text, fish are an important source of nutrition to consumers worldwide and several marine and freshwater species represent important links in the global source-receptor dynamics of methylmercury. However, despite its importance, a coordinated global program for marine and freshwater fish species using accredited laboratories, reproducible data and reliable models is still lacking. In recent years fish mercury science has evolved significantly with its use of advanced technologies and computational models to address this complex and ubiquitous environmental and public health issue. These advances in the field have made it essential that transparency be enhanced to ensure that fish mercury studies used in support of the convention are truly reproducible and scientifically sound. One primary goal of this presentation is to evaluate fish bioinformatics and methods, results and inferential reproducibility as it relates to aggregated uncertainty in mercury fish research models, science, and biomonitoring. I use models, environmental intelligence networks and simulations of the effects of a changing climate on methylmercury in marine and freshwater fish to examine how climate change and the convention itself may create further uncertainties for policymakers to consider. Lastly, I will also present an environmental intelligence framework for fish mercury bioaccumulation models and biomonitoring in support of the evaluation of the effectiveness of the Minamata Convention on Mercury.

77 FR 2958 - Prestressed Concrete Steel Wire Strand From Thailand: Correction to Notice of Opportunity To...

Science.gov (United States)

2012-01-20

... DEPARTMENT OF COMMERCE International Trade Administration [A-549-820] Prestressed Concrete Steel Wire Strand From Thailand: Correction to Notice of Opportunity To Request Administrative Review AGENCY... prestressed concrete steel wire strand (``PC Strand'') from Thailand. See Antidumping or Countervailing Duty...

Rigidity of the polypeptide backbone in the triple-stranded collagen molecule.

Science.gov (United States)

Nemethy, G

1981-02-01

Conformational energy computations were carried out on collagen-like triple-stranded conformations of several polytripeptides with the structure CH3CO(GXY)3NHCH3, where X and Y can be Pro, Ala, or Gly. The computed minimum-energy conformations for various sequences are compared with that computed earlier for poly(Gly-Pro-Pro). Usually, substitution of Ala or Gly residues for Pro does not cause any strain or distortion of the conformation of the triple-stranded complex. Thus, the structure is a very stable and essentially rigid one. Unfavorable interactions were found only in the case of CH3CO(Gly-Ala-Pro)NHCH3. These interactions are a consequence of differences between the residue geometry of Ala and Pro. They result in small changes of some backbone dihedral angles and in an increase of intra- and interchain energies. The presence of a single Gly-Ala-Pro tripeptide within a sequence of Gly-Pro-Pro tripeptides is not sufficient, however, to cause even a small distoration of the triple strand. No deviation of the peptide groups from planarity is required to stabilize the triple-stranded structure.

Magnetization anomaly of Nb3Al strands and instability of Nb3Al Rutherford cables

International Nuclear Information System (INIS)

Yamada, Ryuji; Kikuchi, Akihiro; Wake, Masayoshi

2006-01-01

Using a Cu stabilized Nb 3 Al strand with Nb matrix, a 30 meter long Nb 3 Al Rutherford cable was made by a collaboration of Fermilab and NIMS. Recently the strand and cable were tested. In both cases instability was observed at around 1.5 Tesla. The magnetization of this Nb 3 Al strand was measured first using a balanced coil magnetometer at 4.2 K. Strands showed an anomalously large magnetization behavior around at 1.6 T, which is much higher than the usual B c2 ∼ 0.5 Tesla (4.2 K) of Nb matrix. This result is compared with the magnetization data of short strand samples using a SQUID magnetometer, in which a flux-jump signal was observed at 0.5 Tesla, but not at higher field. As a possible explanation for this magnetization anomaly, the interfilament coupling through the thin Nb films in the strands is suggested. The instability problem observed in low field tests of the Nb 3 Al Rutherford cables is attributed to this effect

Posible impacto en la salud pública del encallamiento de cetáceos en Costa Rica Potential public health impact of the stranding of cetaceans

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Olga Rivas-Solano

2013-06-01

Full Text Available El encallamiento de cetáceos se presenta cuando estos mamíferos llegan a la playa sin poder regresar al mar por sus propios medios. En Costa Rica, la mayoría de los casos se han registrado en las costas del Pacífico. Entre las posibles causas de este fenómeno, están las enfermedades infecciosas como la brucelosis marina. Dicha enfermedad es provocada por bacterias del género Brucella, y se puede transmitir a los humanos. El contacto entre humanos y cetáceos ha venido en aumento debido a actividades recreativas y ocupacionales. Además, el varamiento usualmente llama la atención de turistas y locales, quienes tienden mantener un acercamiento estrecho con el animal encallado para tratar de regresarlo al mar. Lo anterior potencia el riesgo de transmisión de cepas patogénicas desde los mamíferos marinos hacia los humanos y otros animales. En Costa Rica se desarrolló, durante los años 2009 y 2011, un proyecto de investigación en cual participaron expertos de universidades estatales, de instituciones gubernamentales y de la Fundación Keto. Como parte del mismo, se organizaron talleres de capacitación a profesionales en salud, líderes comunales y autoridades locales de la costa pacífica, con el fin de concientizarlos sobre los protocolos a seguir para la atención integral de la problemática de los encallamientos de cetáceos, con miras a prevenir posibles situaciones de riesgo a la salud pública.Cetacean stranding occurs when those animals arrive to the beach without having the possibility to come back to the sea. In Costa Rica, most of the cases have been registered along the pacific coast.  Between the possible causes of the stranding, there are infectious diseases like marine brucellosis. This disease is caused by bacteria from the genus Brucella and it can be transmitted to humans. Contact between humans and cetaceans, has been increased because of touristic and working activities. Besides, stranding phenomenon usually calls

Two-dimensional numerical simulation of flow around three-stranded rope

Science.gov (United States)

Wang, Xinxin; Wan, Rong; Huang, Liuyi; Zhao, Fenfang; Sun, Peng

2016-08-01

Three-stranded rope is widely used in fishing gear and mooring system. Results of numerical simulation are presented for flow around a three-stranded rope in uniform flow. The simulation was carried out to study the hydrodynamic characteristics of pressure and velocity fields of steady incompressible laminar and turbulent wakes behind a three-stranded rope. A three-cylinder configuration and single circular cylinder configuration are used to model the three-stranded rope in the two-dimensional simulation. The governing equations, Navier-Stokes equations, are solved by using two-dimensional finite volume method. The turbulence flow is simulated using Standard κ-ɛ model and Shear-Stress Transport κ-ω (SST) model. The drag of the three-cylinder model and single cylinder model is calculated for different Reynolds numbers by using control volume analysis method. The pressure coefficient is also calculated for the turbulent model and laminar model based on the control surface method. From the comparison of the drag coefficient and the pressure of the single cylinder and three-cylinder models, it is found that the drag coefficients of the three-cylinder model are generally 1.3-1.5 times those of the single circular cylinder for different Reynolds numbers. Comparing the numerical results with water tank test data, the results of the three-cylinder model are closer to the experiment results than the single cylinder model results.

Enzymatic quantification of strand breaks of DNA induced by vacuum-UV radiation

International Nuclear Information System (INIS)

Ito, Takashi

1986-01-01

Hind3 digested plasmid DNA dried on an aluminum plate was irradiated by vacuum-UV at 160 and 195 nm using a synchrotron irradiation system. A change induced in the DNA, presumably a single strand break, was quantified by the aid of the strand break-derived stimulation of poly(ADP-ribose) synthetase activity. The end group of strand breaks so induced was recognized by the enzyme as effectively as that by DNase 1 treatment, suggesting a nicking as the major lesion inflicted on the DNA. The fluence (UV) dependent stimulation of poly(ADP-ribose) synthetase activity was much higher upon 160 nm irradiation than upon 195 nm irradiation. (Auth.)

Causes of Stranding and Mortality, and Final Disposition of Loggerhead Sea Turtles (Caretta caretta) Admitted to a Wildlife Rehabilitation Center in Gran Canaria Island, Spain (1998-2014): A Long-Term Retrospective Study.

Science.gov (United States)

Orós, Jorge; Montesdeoca, Natalia; Camacho, María; Arencibia, Alberto; Calabuig, Pascual

2016-01-01

The aims of this study were to analyze the causes of stranding of 1,860 loggerhead turtles (Caretta caretta) admitted at the Tafira Wildlife Rehabilitation Center in Gran Canaria Island, Spain, from 1998 to 2014, and to analyze the outcomes of the rehabilitation process to allow meaningful auditing of its quality. Primary causes of morbidity were classified into seven categories: entanglement in fishing gear and/or plastics, ingestion of hooks and monofilament lines, trauma, infectious disease, crude oil, other causes, and unknown/undetermined. Final dispositions were calculated as euthanasia (Er), unassisted mortality (Mr), and release (Rr) rates. Time to death (Td) for euthanized and dead turtles, and length of stay for released (Tr) turtles were evaluated. The most frequent causes of morbidity were entanglement in fishing gear and/or plastics (50.81%), unknown/undetermined (20.37%), and ingestion of hooks (11.88%). The final disposition of the 1,634 loggerhead turtles admitted alive were: Er = 3.37%, Mr = 10.34%, and Rr = 86.29%. Er was significantly higher in the trauma category (18.67%) compared to the other causes of admission. The highest Mr was observed for turtles admitted due to trauma (30.67%). The highest Rr was observed in the crude oil (93.87%) and entanglement (92.38%) categories. The median Tr ranged from 12 days (unknown) to 70 days (trauma). This survey is the first large-scale epidemiological study on causes of stranding and mortality of Eastern Atlantic loggerheads and demonstrates that at least 71.72% of turtles stranded due to anthropogenic causes. The high Rr (86.29%) emphasizes the importance of marine rehabilitation centers for conservation purposes. The stratified analysis by causes of admission of the three final disposition rates, and the parameters Td and Tr should be included in the outcome research of the rehabilitation process of sea turtles in order to allow comparative studies between marine rehabilitation centers around the world.

Causes of Stranding and Mortality, and Final Disposition of Loggerhead Sea Turtles (Caretta caretta Admitted to a Wildlife Rehabilitation Center in Gran Canaria Island, Spain (1998-2014: A Long-Term Retrospective Study.

Directory of Open Access Journals (Sweden)

Jorge Orós

Full Text Available The aims of this study were to analyze the causes of stranding of 1,860 loggerhead turtles (Caretta caretta admitted at the Tafira Wildlife Rehabilitation Center in Gran Canaria Island, Spain, from 1998 to 2014, and to analyze the outcomes of the rehabilitation process to allow meaningful auditing of its quality.Primary causes of morbidity were classified into seven categories: entanglement in fishing gear and/or plastics, ingestion of hooks and monofilament lines, trauma, infectious disease, crude oil, other causes, and unknown/undetermined. Final dispositions were calculated as euthanasia (Er, unassisted mortality (Mr, and release (Rr rates. Time to death (Td for euthanized and dead turtles, and length of stay for released (Tr turtles were evaluated.The most frequent causes of morbidity were entanglement in fishing gear and/or plastics (50.81%, unknown/undetermined (20.37%, and ingestion of hooks (11.88%. The final disposition of the 1,634 loggerhead turtles admitted alive were: Er = 3.37%, Mr = 10.34%, and Rr = 86.29%. Er was significantly higher in the trauma category (18.67% compared to the other causes of admission. The highest Mr was observed for turtles admitted due to trauma (30.67%. The highest Rr was observed in the crude oil (93.87% and entanglement (92.38% categories. The median Tr ranged from 12 days (unknown to 70 days (trauma.This survey is the first large-scale epidemiological study on causes of stranding and mortality of Eastern Atlantic loggerheads and demonstrates that at least 71.72% of turtles stranded due to anthropogenic causes. The high Rr (86.29% emphasizes the importance of marine rehabilitation centers for conservation purposes. The stratified analysis by causes of admission of the three final disposition rates, and the parameters Td and Tr should be included in the outcome research of the rehabilitation process of sea turtles in order to allow comparative studies between marine rehabilitation centers around the world.

Prediction of guide strand of microRNAs from its sequence and secondary structure

Directory of Open Access Journals (Sweden)

Ahmed Firoz

2009-04-01

Full Text Available Abstract Background MicroRNAs (miRNAs are produced by the sequential processing of a long hairpin RNA transcript by Drosha and Dicer, an RNase III enzymes, and form transitory small RNA duplexes. One strand of the duplex, which incorporates into RNA-induced silencing complex (RISC and silences the gene expression is called guide strand, or miRNA; while the other strand of duplex is degraded and called the passenger strand, or miRNA*. Predicting the guide strand of miRNA is important for better understanding the RNA interference pathways. Results This paper describes support vector machine (SVM models developed for predicting the guide strands of miRNAs. All models were trained and tested on a dataset consisting of 329 miRNA and 329 miRNA* pairs using five fold cross validation technique. Firstly, models were developed using mono-, di-, and tri-nucleotide composition of miRNA strands and achieved the highest accuracies of 0.588, 0.638 and 0.596 respectively. Secondly, models were developed using split nucleotide composition and achieved maximum accuracies of 0.553, 0.641 and 0.602 for mono-, di-, and tri-nucleotide respectively. Thirdly, models were developed using binary pattern and achieved the highest accuracy of 0.708. Furthermore, when integrating the secondary structure features with binary pattern, an accuracy of 0.719 was seen. Finally, hybrid models were developed by combining various features and achieved maximum accuracy of 0.799 with sensitivity 0.781 and specificity 0.818. Moreover, the performance of this model was tested on an independent dataset that achieved an accuracy of 0.80. In addition, we also compared the performance of our method with various siRNA-designing methods on miRNA and siRNA datasets. Conclusion In this study, first time a method has been developed to predict guide miRNA strands, of miRNA duplex. This study demonstrates that guide and passenger strand of miRNA precursors can be distinguished using their

Conformal geometry and invariants of 3-strand Brownian braids

International Nuclear Information System (INIS)

Nechaev, Sergei; Voituriez, Raphael

2005-01-01

We propose a simple geometrical construction of topological invariants of 3-strand Brownian braids viewed as world lines of 3 particles performing independent Brownian motions in the complex plane z. Our construction is based on the properties of conformal maps of doubly-punctured plane z to the universal covering surface. The special attention is paid to the case of indistinguishable particles. Our method of conformal maps allows us to investigate the statistical properties of the topological complexity of a bunch of 3-strand Brownian braids and to compute the expectation value of the irreducible braid length in the non-Abelian case

Untangling the Strands of the Fourteenth Amendment.

Science.gov (United States)

Lupu, Ira C.

1979-01-01

Explores trends in the Court's interpretation of the libertarian and egalitarian dimensions of the Fourteenth Amendment and offers a theory of the two strands. Available from Michigan Law Review, Hutchins Hall, Ann Arbor, MI 48109; single issues $3.50. (Author/IRT)

Methods for the preparation of large quantities of complex single-stranded oligonucleotide libraries.

Science.gov (United States)

Murgha, Yusuf E; Rouillard, Jean-Marie; Gulari, Erdogan

2014-01-01

Custom-defined oligonucleotide collections have a broad range of applications in fields of synthetic biology, targeted sequencing, and cytogenetics. Also, they are used to encode information for technologies like RNA interference, protein engineering and DNA-encoded libraries. High-throughput parallel DNA synthesis technologies developed for the manufacture of DNA microarrays can produce libraries of large numbers of different oligonucleotides, but in very limited amounts. Here, we compare three approaches to prepare large quantities of single-stranded oligonucleotide libraries derived from microarray synthesized collections. The first approach, alkaline melting of double-stranded PCR amplified libraries with a biotinylated strand captured on streptavidin coated magnetic beads results in little or no non-biotinylated ssDNA. The second method wherein the phosphorylated strand of PCR amplified libraries is nucleolyticaly hydrolyzed is recommended when small amounts of libraries are needed. The third method combining in vitro transcription of PCR amplified libraries to reverse transcription of the RNA product into single-stranded cDNA is our recommended method to produce large amounts of oligonucleotide libraries. Finally, we propose a method to remove any primer binding sequences introduced during library amplification.

Transcription blockage by homopurine DNA sequences: role of sequence composition and single-strand breaks

Science.gov (United States)

Belotserkovskii, Boris P.; Neil, Alexander J.; Saleh, Syed Shayon; Shin, Jane Hae Soo; Mirkin, Sergei M.; Hanawalt, Philip C.

2013-01-01

The ability of DNA to adopt non-canonical structures can affect transcription and has broad implications for genome functioning. We have recently reported that guanine-rich (G-rich) homopurine-homopyrimidine sequences cause significant blockage of transcription in vitro in a strictly orientation-dependent manner: when the G-rich strand serves as the non-template strand [Belotserkovskii et al. (2010) Mechanisms and implications of transcription blockage by guanine-rich DNA sequences., Proc. Natl Acad. Sci. USA, 107, 12816–12821]. We have now systematically studied the effect of the sequence composition and single-stranded breaks on this blockage. Although substitution of guanine by any other base reduced the blockage, cytosine and thymine reduced the blockage more significantly than adenine substitutions, affirming the importance of both G-richness and the homopurine-homopyrimidine character of the sequence for this effect. A single-strand break in the non-template strand adjacent to the G-rich stretch dramatically increased the blockage. Breaks in the non-template strand result in much weaker blockage signals extending downstream from the break even in the absence of the G-rich stretch. Our combined data support the notion that transcription blockage at homopurine-homopyrimidine sequences is caused by R-loop formation. PMID:23275544

Trace elements in two odontocete species (Kogia breviceps and Globicephala macrorhynchus) stranded in New Caledonia (South Pacific)

International Nuclear Information System (INIS)

Bustamante, P.; Garrigue, C.; Breau, L.; Caurant, F.; Dabin, W.; Greaves, J.; Dodemont, R.

2003-01-01

Trace elements in whales on New Caledonia beaches are below levels for concern. - Liver, muscle and blubber tissues of two short-finned pilot whales (Globicephala macrorhynchus) and two pygmy sperm whales (Kogia breviceps) stranded on the coast of New Caledonia have been analysed for 12 trace elements (Al, Cd, Co, Cr, Cu, Fe, organic and total Hg, Mn, Ni, Se, V, and Zn). Liver was shown to be the most important accumulating organ for Cd, Cu, Fe, Hg, Se, and Zn in both species, G. macrorhynchus having the highest Cd, Hg, Se and Zn levels. In this species, concentrations of total Hg are particularly elevated, reaching up to 1452 μg g -1 dry wt. Only a very low percentage of the total Hg was organic. In both species, the levels of Hg are directly related to Se in liver. Thus, a molar ratio of Hg:Se close to 1.0 was found for all specimens, except for the youngest K. breviceps. Our results suggest that G. macrorhynchus have a physiology promoting the accumulation of high levels of naturally occurring toxic elements. Furthermore, concentrations of Ni, Cr and Co are close to or below the detection limit in the liver and muscles of all specimens. This suggests that mining activity in New Caledonia, which typically elevates the levels of these contaminants in the marine environment, does not seem to be a significant source of contamination for these pelagic marine mammals

Rapid assessment of risks to a mobile marine mammal in an ecosystem-scale marine protected area.

Science.gov (United States)

Grech, A; Marsh, H

2008-06-01

Ecosystem-scale networks of marine protected areas (MPAs) are important conservation tools, but their effectiveness is difficult to quantify in a time frame appropriate to species conservation because of uncertainties in the data available. The dugong (Dugong dugon) is a mobile marine species that occurs in shallow inshore waters of an ecosystem-scale network of MPAs (the Great Barrier Reef World Heritage Area [GBRWHA]). We developed a rapid approach to assess risk to dugongs in the region and evaluate options to ameliorate that risk. We used expert opinion and a Delphi technique to identify and rank 5 human factors with the potential to adversely affect dugongs and their sea grass habitats: netting, indigenous hunting, trawling, vessel traffic, and poor-quality terrestrial runoff. We then quantified and compared the distribution of these factors with a spatially explicit model of dugong distribution. We estimated that approximately 96% of habitat of high conservation value for dugongs in the GBRWHA is at low risk from human activities. Using a sensitivity analysis, we found that to decrease risk, commercial netting or indigenous hunting had to be reduced in remote areas and the effects of vessel traffic, terrestrial runoff, and commercial netting had to be reduced in urban areas. This approach enabled us to compare and rank risks so as to identify the most severe risks and locate specific sites that require further management attention.

Estimation of Prestress Force Distribution in Multi-Strand System of Prestressed Concrete Structures Using Field Data Measured by Electromagnetic Sensor.

Science.gov (United States)

Cho, Keunhee; Cho, Jeong-Rae; Kim, Sung Tae; Park, Sung Yong; Kim, Young-Jin; Park, Young-Hwan

2016-08-18

The recently developed smart strand can be used to measure the prestress force in the prestressed concrete (PSC) structure from the construction stage to the in-service stage. The higher cost of the smart strand compared to the conventional strand renders it unaffordable to replace all the strands by smart strands, and results in the application of only a limited number of smart strands in the PSC structure. However, the prestress forces developed in the strands of the multi-strand system frequently adopted in PSC structures differ from each other, which means that the prestress force in the multi-strand system cannot be obtained by simple proportional scaling using the measurement of the smart strand. Therefore, this study examines the prestress force distribution in the multi-strand system to find the correlation between the prestress force measured by the smart strand and the prestress force distribution in the multi-strand system. To that goal, the prestress force distribution was measured using electromagnetic sensors for various factors of the multi-strand system adopted on site in the fabrication of actual PSC girders. The results verified the possibility to assume normal distribution for the prestress force distribution per anchor head, and a method computing the mean and standard deviation defining the normal distribution is proposed. This paper presents a meaningful finding by proposing an estimation method of the prestress force based upon field-measured data of the prestress force distribution in the multi-strand system of actual PSC structures.

Ontario electricity industry restructuring : preliminary asset valuation and calculation of stranded debt

International Nuclear Information System (INIS)

1998-01-01

The rationale for restructuring Ontario's electricity industry was restated. Financial elements of the Government's White Paper on the electrical industry included the following: (1) establishing a level playing field on taxes and regulation, (2) restructuring Ontario Hydro into new companies with clear business mandates, and (3) taking action to put the new companies on solid financial ground. To achieve these objectives requires valuation of the new companies as a key part in the restructuring process. This Ministry of Finance document contains preliminary estimates of the total debt and liabilities of Ontario Hydro ($ 39.1 billion), the value of the new generation and service companies ($ 15.8 billion), and the stranded debt ($ 23.3 billion, less the value of dedicated revenue streams of $ 15.4 billion, equal to the residual stranded debt of $ 7.9 billion). The method by which the stranded debt was calculated is also described. It is stressed that the overriding principles governing the financial restructuring plan are to achieve restructuring without increasing electricity rates, to retain maximum value in the electricity sector until stranded debt is retired, and to recover stranded debt from the electricity sector and not from taxpayers. Ministry advisors indicate that these preliminary valuations would allow the new companies to operate as commercial companies in a competitive market and receive investment grade credit ratings. 44 figs

Ionizing-radiation induced DNA double-strand breaks: A direct and indirect lighting up

International Nuclear Information System (INIS)

Vignard, Julien; Mirey, Gladys; Salles, Bernard

2013-01-01

The occurrence of DNA double-strand breaks (DSBs) induced by ionizing radiation has been extensively studied by biochemical or cell imaging techniques. Cell imaging development relies on technical advances as well as our knowledge of the cell DNA damage response (DDR) process. The DDR involves a complex network of proteins that initiate and coordinate DNA damage signaling and repair activities. As some DDR proteins assemble at DSBs in an established spatio-temporal pattern, visible nuclear foci are produced. In addition, post-translational modifications are important for the signaling and the recruitment of specific partners at damaged chromatin foci. We briefly review here the most widely used methods to study DSBs. We also discuss the development of indirect methods, using reporter expression or intra-nuclear antibodies, to follow the production of DSBs in real time and in living cells

Viral diseases of marine invertebrates

Science.gov (United States)

Johnson, P. T.

1984-03-01

Approximately 40 viruses are known from marine sponges; turbellarian and monogenetic flatworms; cephalopod, bivalve, and gastropod mollusks; nereid polychaetes; and isopod and decapod crustaceans. Most of the viruses can be tentatively assigned to the Herpesviridae, Baculoviridae, Iridoviridae, Adenoviridae, Papovaviridae, Reoviridae, “Birnaviridae”, Bunyaviridae, Rhabdoviridae, and Picornaviridae. Viruslike particles found in oysters might be representatives of the Togaviridae and Retroviridae. Enveloped single-stranded RNA viruses from crustaceans have developmental and morphological characteristics intermediate between families, and some show evidence of relationships to the Paramyxoviridae as well as the Bunyaviridae or Rhabdoviridae. Certain small viruses of shrimp cannot be assigned, even tentatively, to a particular family. Some viruses cause disease in wild and captive hosts, others are associated with disease states but may not be primary instigators, and many occur in apparently normal animals. The frequency of viral disease in natural populations of marine invertebrates is unknown. Several viruses that cause disease in captive animals, with or without experimental intervention, have also been found in diseased wild hosts, including herpeslike viruses of crabs and oysters, iridovirus of octopus, and reolike and bunyalike viruses of crabs. Iridolike viruses have been implicated in massive mortalities of cultured oysters. Baculoviruses, and IHHN virus, which is of uncertain affinities, cause economically damaging diseases in cultured penaeid shrimp. Double or multiple viral infection is common in crabs. For example, a reolike virus and associated rhabdolike virus act synergistically to cause paralytic and fatal disease in Callinectes sapidus. Information on host range, most susceptible stage, and viral latency is available only for viruses of shrimp. One baculovirus attacks five species of New World penaeid shrimp. IHHN virus infects three species of

Double Strand Break Repair, one mechanism can hide another: Alternative non-homologous end joining

International Nuclear Information System (INIS)

Rass, E.; Grabarz, A.; Bertrand, P.; Lopez, B.S.

2012-01-01

DNA double strand breaks are major cytotoxic lesions encountered by the cells. They can be induced by ionizing radiation or endogenous stress and can lead to genetic instability. Two mechanisms compete for the repair of DNA double strand breaks: homologous recombination and non-homologous end joining (NHEJ). Homologous recombination requires DNA sequences homology and is initiated by single strand resection. Recently, advances have been made concerning the major steps and proteins involved in resection. NHEJ, in contrast, does not require sequence homology. The existence of a DNA double strand break repair mechanism, independent of KU and ligase IV, the key proteins of the canonical non homologous end joining pathway, has been revealed lately and named alternative non homologous end joining. The hallmarks of this highly mutagenic pathway are deletions at repair junctions and frequent use of distal micro-homologies. This mechanism is also initiated by a single strand resection of the break. The aim of this review is firstly to present recent data on single strand resection, and secondly the alternative NHEJ pathway, including a discussion on the fidelity of NHEJ. Based on current knowledge, canonical NHEJ does not appear as an intrinsically mutagenic mechanism, but in contrast, as a conservative one. The structure of broken DNA ends actually dictates the quality repair of the alternative NHEJ and seems the actual responsible for the mutagenesis attributed beforehand to the canonical NHEJ. The existence of this novel DNA double strand breaks repair mechanism needs to be taken into account in the development of radiosensitizing strategies in order to optimise the efficiency of radiotherapy. (authors)

Artificial neural networks for modeling time series of beach litter in the southern North Sea.

Science.gov (United States)

Schulz, Marcus; Matthies, Michael

2014-07-01

In European marine waters, existing monitoring programs of beach litter need to be improved concerning litter items used as indicators of pollution levels, efficiency, and effectiveness. In order to ease and focus future monitoring of beach litter on few important litter items, feed-forward neural networks consisting of three layers were developed to relate single litter items to general categories of marine litter. The neural networks developed were applied to seven beaches in the southern North Sea and modeled time series of five general categories of marine litter, such as litter from fishing, shipping, and tourism. Results of regression analyses show that general categories were predicted significantly moderately to well. Measured and modeled data were in the same order of magnitude, and minima and maxima overlapped well. Neural networks were found to be eligible tools to deliver reliable predictions of marine litter with low computational effort and little input of information. Copyright © 2014 Elsevier Ltd. All rights reserved.

Heavy metal residues in tissues of marine turtles

International Nuclear Information System (INIS)

Storelli, M.M.; Marcotrigiano, G.O.

2003-01-01

Heavy metal concentrations in the tissues of marine turtles are presented. The most frequently monitored elements are mercury, cadmium and lead; and the tissues mainly analysed in nearly all the stranded individuals are muscle, liver and kidney. The highest mercury and cadmium levels were found in liver and kidney respectively; the majority of the lead burden existed in bones and carapace, while arsenic was present mainly in muscle tissue. Mercury occurred quite completely as methylmercury in muscle, whereas in liver the main form was the inorganic one. Arsenic was exclusively present in the metallorganic form either in muscle tissue or in liver. Metals in the eggs were mainly present in the yolk. Significantly higher concentration of mercury, copper, zinc and iron were found in yolk than albumen, while shell contained highest levels of manganese and copper. The load of trace metals in these animals strictly correlated with the species seems to depend on their different food behaviour

Heavy metal residues in tissues of marine turtles

Energy Technology Data Exchange (ETDEWEB)

Storelli, M.M.; Marcotrigiano, G.O

2003-04-01

Heavy metal concentrations in the tissues of marine turtles are presented. The most frequently monitored elements are mercury, cadmium and lead; and the tissues mainly analysed in nearly all the stranded individuals are muscle, liver and kidney. The highest mercury and cadmium levels were found in liver and kidney respectively; the majority of the lead burden existed in bones and carapace, while arsenic was present mainly in muscle tissue. Mercury occurred quite completely as methylmercury in muscle, whereas in liver the main form was the inorganic one. Arsenic was exclusively present in the metallorganic form either in muscle tissue or in liver. Metals in the eggs were mainly present in the yolk. Significantly higher concentration of mercury, copper, zinc and iron were found in yolk than albumen, while shell contained highest levels of manganese and copper. The load of trace metals in these animals strictly correlated with the species seems to depend on their different food behaviour.

The general atomic strand winding machine

International Nuclear Information System (INIS)

Matt, P.

1976-01-01

In conjunction with the integrated development of their high temperature gas cooled reactors (HTGR), General Atomic of San Diego, USA, also developed a strand winding system for the horizontal prestressing of pressure vessels. The machine lay-out, its capabilities and the test program carried out in the laboratory and on a full scale pressure vessel model are described. (author)

The (not so immortal strand hypothesis

Directory of Open Access Journals (Sweden)

Cristian Tomasetti

2015-03-01

Significance: Utilizing an approach that is fundamentally different from previous efforts to confirm or refute the immortal strand hypothesis, we provide evidence against non-random segregation of DNA during stem cell replication. Our results strongly suggest that parental DNA is passed randomly to stem cell daughters and provides new insight into the mechanism of DNA replication in stem cells.

A new building block for DNA network formation by self-assembly and polymerase chain reaction.

Science.gov (United States)

Bußkamp, Holger; Keller, Sascha; Robotta, Marta; Drescher, Malte; Marx, Andreas

2014-01-01

The predictability of DNA self-assembly is exploited in many nanotechnological approaches. Inspired by naturally existing self-assembled DNA architectures, branched DNA has been developed that allows self-assembly to predesigned architectures with dimensions on the nanometer scale. DNA is an attractive material for generation of nanostructures due to a plethora of enzymes which modify DNA with high accuracy, providing a toolbox for many different manipulations to construct nanometer scaled objects. We present a straightforward synthesis of a rigid DNA branching building block successfully used for the generation of DNA networks by self-assembly and network formation by enzymatic DNA synthesis. The Y-shaped 3-armed DNA construct, bearing 3 primer strands is accepted by Taq DNA polymerase. The enzyme uses each arm as primer strand and incorporates the branched construct into large assemblies during PCR. The networks were investigated by agarose gel electrophoresis, atomic force microscopy, dynamic light scattering, and electron paramagnetic resonance spectroscopy. The findings indicate that rather rigid DNA networks were formed. This presents a new bottom-up approach for DNA material formation and might find applications like in the generation of functional hydrogels.

Mouse RAD54 affects DNA double-strand break repair and sister chromatid exchange

NARCIS (Netherlands)

H.B. Beverloo (Berna); R.D. Johnson (Roger); M. Jasin (Maria); R. Kanaar (Roland); J.H.J. Hoeijmakers (Jan); M.L.G. Dronkert (Mies)

2000-01-01

textabstractCells can achieve error-free repair of DNA double-strand breaks (DSBs) by homologous recombination through gene conversion with or without crossover. In contrast, an alternative homology-dependent DSB repair pathway, single-strand annealing (SSA), results in deletions. In this study, we

DNA template strand sequencing of single-cells maps genomic rearrangements at high resolution

NARCIS (Netherlands)

Falconer, Ester; Hills, Mark; Naumann, Ulrike; Poon, Steven S. S.; Chavez, Elizabeth A.; Sanders, Ashley D.; Zhao, Yongjun; Hirst, Martin; Lansdorp, Peter M.

DNA rearrangements such as sister chromatid exchanges (SCEs) are sensitive indicators of genomic stress and instability, but they are typically masked by single-cell sequencing techniques. We developed Strand-seq to independently sequence parental DNA template strands from single cells, making it

NbTi Strands Verification for ITER PF CICC Process Qualification of CNDA

Science.gov (United States)

Liu, F.; Liu, H.; Liu, S.; Liu, B.; Lei, L.; Wu, Y.

2014-05-01

China is in charge of most of Poloidal Field (PF) conductors production for the International Thermonuclear Experimental Reactor (ITER). The execution for PF conductors shall be in three main phases. According to ITER Procurement Arrangement (PA), the Domestic Agency (DA) shall be required to verify the room and low temperature acceptance tests carried out by the strand suppliers. As the reference laboratory of Chinese DA (CNDA), the superconducting strands test laboratory of Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP) was undertaking the task of strands verification for ITER conductors. The verification test includes: diameter, Nickel plating thickness, copper-to-non-copper volume ratio, twist pitch direction and length, standard critical current (IC) and resistive transition index (n), residual resistance ration (RRR), and hysteresis loss. 48 NbTi strands with 7 billets were supplied for the PF Cable-In-Conduit Conductor (CICC) process qualification. In total, 54 samples were measured. The verification level for PF CICC process qualification was 100%. The test method, facility and results of each item are described in detail in this publication.

Interstrand cross-links arising from strand breaks at true abasic sites in duplex DNA

OpenAIRE

Yang, Zhiyu; Price, Nathan E.; Johnson, Kevin M.; Wang, Yinsheng; Gates, Kent S.

2017-01-01

Abstract Interstrand cross-links are exceptionally bioactive DNA lesions. Endogenous generation of interstrand cross-links in genomic DNA may contribute to aging, neurodegeneration, and cancer. Abasic (Ap) sites are common lesions in genomic DNA that readily undergo spontaneous and amine-catalyzed strand cleavage reactions that generate a 2,3-didehydro-2,3-dideoxyribose sugar remnant (3?ddR5p) at the 3?-terminus of the strand break. Interestingly, this strand scission process leaves an electr...

Facing a Problem of Electrical Energy Quality in Ship Networks-measurements, Estimation, Control

Institute of Scientific and Technical Information of China (English)

Tomasz Tarasiuk; Janusz Mindykowski; Xiaoyan Xu

2003-01-01

In this paper, electrical energy quality and its indices in ship electric networks are introduced, especially the meaning of electrical energy quality terms in voltage and active and reactive power distribution indices. Then methods of measurement of marine electrical energy indices are introduced in details and a microprocessor measurement-diagnosis system with the function of measurement and control is designed. Afterwards, estimation and control of electrical power quality of marine electrical power networks are introduced. And finally, according to the existing method of measurement and control of electrical power quality in ship power networks, the improvement of relative method is proposed.

THE INSTABILITY AND NON-EXISTENCE OF MULTI-STRANDED LOOPS WHEN DRIVEN BY TRANSVERSE WAVES

Energy Technology Data Exchange (ETDEWEB)

Magyar, N.; Van Doorsselaere, T., E-mail: norbert.magyar@wis.kuleuven.be [Centre for Mathematical Plasma Astrophysics (CmPA), KU Leuven, Celestijnenlaan 200B bus 2400, 3001 Leuven (Belgium)

2016-06-01

In recent years, omni-present transverse waves have been observed in all layers of the solar atmosphere. Coronal loops are often modeled as a collection of individual strands in order to explain their thermal behavior and appearance. We perform three-dimensional (3D) ideal magnetohydrodynamics simulations to study the effect of a continuous small amplitude transverse footpoint driving on the internal structure of a coronal loop composed of strands. The output is also converted into synthetic images, corresponding to the AIA 171 and 193 Å passbands, using FoMo. We show that the multi-stranded loop ceases to exist in the traditional sense of the word, because the plasma is efficiently mixed perpendicularly to the magnetic field, with the Kelvin–Helmholtz instability acting as the main mechanism. The final product of our simulation is a mixed loop with density structures on a large range of scales, resembling a power-law. Thus, multi-stranded loops are unstable to driving by transverse waves, and this raises strong doubts on the usability and applicability of coronal loop models consisting of independent strands.

Pseudo-proxy evaluation of climate field reconstruction methods of North Atlantic climate based on an annually resolved marine proxy network

Directory of Open Access Journals (Sweden)

M. Pyrina

2017-10-01

Full Text Available Two statistical methods are tested to reconstruct the interannual variations in past sea surface temperatures (SSTs of the North Atlantic (NA Ocean over the past millennium based on annually resolved and absolutely dated marine proxy records of the bivalve mollusk Arctica islandica. The methods are tested in a pseudo-proxy experiment (PPE setup using state-of-the-art climate models (CMIP5 Earth system models and reanalysis data from the COBE2 SST data set. The methods were applied in the virtual reality provided by global climate simulations and reanalysis data to reconstruct the past NA SSTs using pseudo-proxy records that mimic the statistical characteristics and network of Arctica islandica. The multivariate linear regression methods evaluated here are principal component regression and canonical correlation analysis. Differences in the skill of the climate field reconstruction (CFR are assessed according to different calibration periods and different proxy locations within the NA basin. The choice of the climate model used as a surrogate reality in the PPE has a more profound effect on the CFR skill than the calibration period and the statistical reconstruction method. The differences between the two methods are clearer for the MPI-ESM model due to its higher spatial resolution in the NA basin. The pseudo-proxy results of the CCSM4 model are closer to the pseudo-proxy results based on the reanalysis data set COBE2. Conducting PPEs using noise-contaminated pseudo-proxies instead of noise-free pseudo-proxies is important for the evaluation of the methods, as more spatial differences in the reconstruction skill are revealed. Both methods are appropriate for the reconstruction of the temporal evolution of the NA SSTs, even though they lead to a great loss of variance away from the proxy sites. Under reasonable assumptions about the characteristics of the non-climate noise in the proxy records, our results show that the marine network of Arctica